Issuu

Valve & Actuator

Overview

PROCESS FLOW TECHNOLOGIES TECHNICAL TRAINING

Inroduction

Gate Valves

Globe Valves

4. Diaphragm Valves 5.

Pressure Control Valves

6. Check Valves 7.

Butterfly Valves

Ball Valves

9. Plug Valves 10. Valve Testing 11. Actuators 12a. Pneumatic Actuators 12b. Electric Actuators 13. Valve Sizing 14. Actuator Sizing

INDEX

1 Valve & Actuator Online Training Module

Introduction

INTRODUCTION

COURSE OVERVIEW Valve & Actuator Overview

Basic information on common valves and actuators Provides our employees with a better understanding of our products Helps employees provide the best solutions to our customers.

This course, will provide a basic overview of the most common valves and actuators we see in the industry, giving you a better understanding of our products and helping you come up with better solutions. Whether you are customer facing in the shop designing, or focused on one product line or product area, it’s good to know the types of products that we manufacture, as well as the industries and applications to which they apply.

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INTRODUCTION

TERMINAL OBJECTIVE Upon completion of this course, students will have basic knowledge of various types of valves and actuators, including:

Component parts Industry applications Advantages and disadvantages Problems and potential causes Crane brands and products

Upon completing the course, you will have a basic understanding of the various types of valves, including some of the component parts. We’ll also go through the various industry applications, advantages or disadvantages of valves for those applications, the problems and potential causes for those problems, and the Crane brands and products we manufacture.

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INTRODUCTION

LEARNING OBJECTIVES At the completion of this lesson, you will be able to: 1. Define, ”valve.” 2. List four categories of valves based on method of operation. 3. List the three main functions for valves. 4. Identify four types of end connections for valves. 5. Define, “trim.” 6. Define, “valve gasket.” 7. Identify the materials used in the manufacturing of: valve bodies valve linings valve gaskets valve seats 8. Identify Crane brands that manufacture valves.

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In this section, we will define what a valve is. We’ll also go through the four categories of valves based on the method of operation, the three main valve functions, and the four types of the most common end connections. By the end of the section, you’ll also know what trims, and gaskets are, and you’ll be able to identify some materials for valve bodies, linings, gaskets, and valve seats. Finally, we’ll review the typical materials that we would use in those valves for various applications and then identify the Crane brands that manufacture those particular valves.

VALVE & ACTUATOR OVERVIEW

INTRODUCTION

DEF INITION

VALVE A mechanical device that turns on and off, regulates, modulates or isolates the rate, volume, pressure or the direction of liquids, gasses, slurries or dry materials through a pipeline, chute or passageway.

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INTRODUCTION

CATEGORIES OF VALVES

LINEAR MOTION

ROTARY MOTION

In linear valves, the linear motion is pretty straightforward. It goes up or down, to open or close the valve. The member closure element is actually lifting out of the waterway or the closure element is moving into the waterway. So it is a linear motion movement. This happens to be a gate moving another gate out of the way.

Valve Types Gate Globe Diaphragm Pinch/Clamp Safety Relief Butterfly Ball Plug

In a rotary valve, the motion is typically 90°. So, if you think about a butterfly valve, ball valve, plug valve, it takes 90° to go from fully open to fully closed, either clockwise or counterclockwise.

Linear Motion        

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Rotary Motion        

VALVE & ACTUATOR OVERVIEW

INTRODUCTION

CHECK

PRESSURE CONTROL

Check valves are essentially flow reversal valves, and the most common are cast steel check valves and swing check valves. This type of valve is automated by the fluid flow itself. In other valves, some external force is needed to operate them, either manually or with of actuator.

Safety relief valves can be found on hot water heaters so that if something goes wrong and it overheats, instead of blowing up, it relieves the pressure. These valves have a manual override and can push that lever to relieve pressure.

HOT WATER HEATER PRESSURE RELIEF VALVE

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VALVE FUNCTIONS Valves have three main functions: on-off, backflow prevention (which occurs in check valves) and control where you’re controlling the pressure.

ON/OFF

BACKFLOW PREVENTION

CONTROL Control Valves include:

Specific examples of ONOFF valves include:

Linear and Rotary Types that provide finite control of fluid variables.

Linear/Multi-Turn and Rotary/

Quarter-Turn Low pressure drop Operation:

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TYPES OF CONNECTIONS FLANGED

THREADED

TYPES OF CONNECTIONS

SOCKET WELD

BUTT WELD

RO LE Connections are what ensures the valves seal. CRANE PROCESS FLOW TECHNOLOGIES

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FLANGED CONNECTIONS

RAISED FACE

RING TYPE JOINT RTJ

A flanged connection can either have a raised face, a flat face, or a ring type joint.

face flanges are frequently those in which the mating flange or flanged fitting is made from a casting.

On the far left, you can see the raised face flange connection which is characterized by a small raised face. This type of flange connection is very typical for ball valves, and cast steel gate, globe, and check valves. The Raised Face flange is the most common type used in process plant applications.

Ring-type joint flanges are reserved for higher pressure applications where there is an energizing seal clamped inside this annular groove. The Ring Type Joint flanges are typically used in high pressure and/ or high-temperature services.

In valves like ductile iron or cast iron, you’ll typically see a flat face flange connection. Applications using flat

FLAT FACE

Most flanged end connections adhere to an industry standard. These standards define specific criteria that must be met in order to facilitate the use of products from

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various manufacturers. ANSI is the American National Standards Institute. Together with the ASME (American Society of Mechanical Engineers), they have developed and published a standard for flange connections. That standard is ASME/ANSI B16.5. There is also a European standard that is similar, but NOT THE SAME. That standard is DIN, which is an acronym for the German translation of “German Institute for Standardization.”

VALVE & ACTUATOR OVERVIEW

INTRODUCTION

FLANGED CONNECTIONS

FLANGED RAISED FACE

Here you can see the a raised face gasket on a cast steel gate valve.

FLANGED FLAT FACE

Here is a flat face as cast which would be in a cast iron valve.

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FLANGED RING TYPE JOINT RTJ

And this is a ring-type joint. Here you can see the groove that the ring would fit into. Again this would typically appear on a higher pressure class valve.

VALVE & ACTUATOR OVERVIEW

INTRODUCTION

THREADED CONNECTIONS

Threaded connections are solid connections that

are used in non-critical applications. It’s probably the least engineered connection. Where there is a flanged connection, there will be

bolts and the bolts will have specific torque that the bolts are supposed to torque to, making it a very controlled joint. However, with a threaded connection, there is a tapered thread, so, the tightness of the connection depends on how much the pipe is turned into the thread. So, it's basically up to the operator to tighten it until it doesn't leak. Many times there will be a pipe compound that can be used or thread Teflon tape, but it's not as robust of a solution. Therefore, you’ll typically see this connection more in hot water, cold water, and Chilton application, although today, they’re becoming more obsolete.

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SOCKET CONNECTIONS

The socket weld connection is a socket where the pipe

fits into the socket and there is a seal weld on the outside. This type of connection would not be used in corrosive applications because the corrodent gets lodged in the connection crack, and as it corrodes, would ultimately break the weld. Once a weld is broken, it will no longer seal, which could be very serious if toxic liquids are present.

BUTT WELD CONNECTIONS

The Butt weld is a full penetration weld, which means

during the time of its weld, it is reinforced by multiple passes. It is typically used in steam applications, like those in power plants, as steam leaks could be hazardous, so the reinforced weld is needed. A butt joint connection like this is robust, but if a repair is required, you don’t have to take the valve out as inline because it is welded and part of the pipe.

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STANDARDS ORGANIZATIONS We have a class for standards and specifications which are a two-day class in itself, but we wanted to provide a list of the key standards here so that you can see that there are multiple standard organizations all over the world that helps guide designers through the valve design process and that help end-users apply the valve. By having these standards in place, valves are interchangeable from a position in the pipeline. Within Crane, we strive to offer features that make our valves less likely to be replaced in the field. Although valves like gate, globe, and check valves have to be replaced from time to time. We’ve worked to come up with a value proposition that makes Crane valves superior, but the standards drive it to a common denominator. SO we’re building the valves to meet the standard, which is the baseline, and all of the standards applicable for that specific application has to be met. So let’s walk through those listed here. API stands for the American Petroleum Institute and apply to most refineries globally, although there are a few that don’t use API standards for the pipeline or the valving. ASME, or the American Society of Mechanical Engineers, applies to the design standards for valves manufactured and used in America. So, most of the valves that we are producing in Satara would be

manufactured to ASME standards, as well.

Automation Society. These two apply primarily to control valves.

AWWA, or the American Water Works Association, are for valves that are used in waterworks facilities.

ISO is the international standards organization, which is a worldwide standard organization and is driving that standardization from a global standpoint, so there’s some crossover with ASME and CEN.

BSI stands for the British Standards Institute. We do make some valves for Crane fluid systems in Ipswich for the UK market, and we also sell other valves that have to be manufactured according to British standards. The specifications of these standard are very close to the ASME standards. Cenelec (CEN) represents the European standards of valve design and DIN represents specifically the German standards. FCI stands for the Fluid Control Institute and ISA are for the Instrumentation, Systems and

And finally, MSS is the manufacturers standardization society. It’s an organization based in the]/- United States that comes up with standard practices and recommendations for valves. So that’s a brief overview, so you’re at least familiar with each one, as we’ll be referencing some of the standards in this course. If you’re interested in learning more about each of these standards, the technical standards overview the course addresses them in detail.

API

American Petroleum Institute

ASME

American Society of Mechanical Engineers

AWWA

American Water Works Association

BSI

British Standards Institute

CEN

European Committee for Standardization (Cenelec)

DIN

Deutsches Institut fur Normung E. V.

FCI

Fluid Controls Institute

ISA

Instrumentation, Systems, and Automation Society

ISO

International Organization for Standards

MSS

Manufacturers Standardization Society

Technical Standards Overview course addresses in detail 16

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STANDARDS ORGANIZATIONS Another topic we will cover in this course Is a pressure class. As mentioned, ASME is the American society of Mechanical engineers and its B16.34 standard is the go-to resource for manufacturing valves, offering standard pressure, temperature and class ratings. This particular chart example refers to a cast steel designation, either forging A105 or casting A216 WCB, which is the standard cast steel designation for gate, globe and check valves.

the column, you’ll see the different pressure ratings inside the valve in psi will vary based on the temperature. As the temperature increases, and the pressure decreases. Based on empirical evidence, over time, as far as creep rates and the capability of the materials to be able to withstand the temperature and maintain their physical characteristics.

So let’s take a look at the chart, a class 150 valve at ambient temperature range (-20 to 100 If you look at the second column, degrees Fahrenheit) is 285 for you’ll see it refers to a valve with carbon steel valve. (AS: animate a pressure class of 150 at various the 285 within the chart – red temperatures. As you look down boxes) Temp. ºF 150 300 400 600 900 1500 2500

If this we a Monell valve, the mechanical properties of Monell are less than cast steel, so the capability withstanding pressure is less and these numbers would all be lower. So these numbers are based on the material, and when you look at the pressure class you can then determine whether the valve is suitable for the application. This is just a brief overview that provides the basics of understanding pressure class ratings, because I will be mentioning pressure classes in this course.

-20 to 100

285

700

900

1480

2220

3705

6170

200

260

675

900

1350

2025

3375

5625

300

230

655

875

1315

1970

3280

5470

400

200

635

845

1270

1900

3170

5280

500

170

600

800

1200

1795

2995

4990

600

140

550

730

1095

1640

3735

4560

650

125

535

715

1075

1610

2685

4475

700

110

535

710

1005

1600

2665

4440

750

505

670

1010

1510

2520

4200

800

410

550

825

1235

2060

3430

850

270

355

535

805

1340

2230

900

170

230

345

515

860

1430

Material Group No. 1.1

950

105

140

205

310

515

860

Forging A105

1000

105

155

260

430

Casting A216 WCB

ASME B16.34 - Standard Class, Pressure-Temperature Rating CRANE PROCESS FLOW TECHNOLOGIES

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D E FI NI TI ON

Flow Coefficient (Cv / Kv) The amount of water flow at 60 degrees F, in gallons per minute, at a pressure drop of one pound per square inch across a component. Cv / Kv numbers allow ready comparison of the flow capability of the valve; the higher capability. the number, the higher the flow capability

Flow Flow-through the vales is very important, especially for an end end-user that is sizing the line so that he or she knows what size pumps to use for the pipeline. T Today, we have higher efficiency standards and requirements that state the higher your Cv is for a particular valve, the less the pump needs to run. Variable frequency pumps are used to slow the pump, which takes less energy, so the size of the pipeline or the size of the valve or seats via the valve are all relevant. For example, if we o offer a check valve with flow capacity that’s 15% greater then the competitor, then the customer doesn’t need to have his pump running as hard to overcome the resistance of flow-through that particular check valve. Typically, there are thousands of check valves within a plant running 24/7, 365 days a 18

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year, and 15% efficiency represents a significant amount of savings. Our customers want to know-how they make their plant operate efficiently. Cv is the amount of water flow at 60°F in gallons per minute at a pressure drop 1 pound per square inch across the component. It is a normalized, dimensionless coefficient that allows you to compare apples to apples, or one component versus another component. The Cv isn’t just for valves, but it’s a measure of the capacity of that component to be able to flow fluid right. This is important as we compare different valve types, because part of the comparison is its capacity and capability of flowing fluids. In North America, the flow coefficient is defined as Cv and in Europe it’s Kv.

VALVE & ACTUATOR OVERVIEW

INTRODUCTION

D E FI N I T I ON

Valve Trim Valve trim is a collective name for the replaceable parts in a Valve. A typical valve design includes a seat, stem, and sleeves needed to guide the stem. Valve trim is a collective name for replaceable parts. A valve design includes a seat, stem, and sleeves, all components. So, in the case of a gate valve with a unique trim for chlorine service, there would typically be some Monell components that are resistant to corrosion in chlorine applications. Therefore, in this case, instead of having carbon steel or plated steel which would corrode very easily in chlorine, you’d have the Monell components.

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DE FINITION

Gasket & Packing Gaskets & packing are the seals used to prevent the leakage of a gas or fluids from valves. A gasket is a mechanical seal which fills the space between two or more mating surfaces, generally to prevent leakage from or into the joined objects while under compression. Gasket and packing prevent valve leakage. In the case of a flanged joint between a bonnet and body, a gasket would be present to keep the liquid inside from spilling outside. That’s what we call packing a gasket. Gasket and packing prevent valve leakage. In the case of a flanged joint between a bonnet and body, a gasket would be present to keep the liquid inside from spilling outside. That’s what we call packing a gasket.

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KN O W L E DGE CH E CK

Why does a valve need to be sealed? Whether it’s a linear stem on a gate valve or globe valve, or a rotary stem on a plug or butterfly valve, the packing prevents leakage and hazardous emissions, chemicals, radioactive material, and gas. Of course, preventing those materials from spilling is paramount, but even if they aren’t hazardous materials, keeping it inside the valve is the goal.  Hazardous emissions  Chemicals  Radioactive material  Gas  Negatively affect other system components  Steam leaks can cause burns

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VALVE SEALS

COMMON TYPES OF GASKETS

There are three common gaskets: flat baskets, spiral wound baskets and ring-type joints. In spiral wound gaskets, there are alternating layers of metal with a filler element that makes the seal. These are incredibly common today. And you may remember that ring-type joints are used for high pressure applications.

FLAT

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RING TYPE JOINT

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VALVE SEALS

TYPES OF VALVE STEM SEALS

ORING

STUFFING BOX

An O-ring seal is particularly resilient in a butterfly valve and is more commonly used in lower temperature requirements since they are only suitable for whatever the elastomer temperature is.

ORING / STUFFING BOX

The stuffing box is the second type of seal. With this one, Teflon can be added, and you can graph oil gasket in for very high temperatures. In a packing ring used in the process industry, you’ll see some stuffing box type of design. With a stuffing box, the packing is being stuffed in and there’s a gland follower that, when the nuts are tightened, is driven down, thereby tightening the packing.

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The O-ring has a backup stuffing ring. This type is used primarily in the oil gas pipeline applications with ambient temperatures requirements. The O-rings are resistant to the petroleum fluids and the stuffing ring is made of graphite for fire resistance. If the pipeline catches fire and the O-rings disintegrate, the graphite packing will keep the liquid inside the valve.

VALVE & ACTUATOR OVERVIEW

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VALVE SEALS PACKING

Common to all gate and globe valves

Graph oil packing in a globe valve.

PACKING MATERIALS

The packing materials could be braided graphite, Teflon with aramid fiber, solid Teflon, or laminated graphite. The application dictates which you would use. For example, the gate, globe, and check valves that we build by our joint venture partner Samar, Pacific Valves utilize a combination of laminated graphite with the top and bottom rings being braided graphite.

Usually, there are two or three rings of laminated graphite sandwiched between two rings of braided graphite. The braided graphite acts as a wiper and keeps the laminated graphite contained. Typically, there’s a small crevice between the OD and the ID that tends to migrate, the braided graphite prevents that from happening.

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Braided graphite Teflon with aramid fibers Solid Teflon Laminated graphite

VALVE & ACTUATOR OVERVIEW

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VALVE SEALS

PACKING DESIGNS

SOLID

DIE FORMED RINGS

ROPE

MANY OTHERS

The braided graphite on the top and bottom, and laminated graphite on the inside. Other types of packing designs include die-formed rings and rope, as well, as many others are not listed here.

Here is an up close view of braided graphite packed inside a stuffing box.

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VALVE MATERIALS

Valve bodies are commonly made from brass, bronze, cast iron, steel, stainless steel, alloy steel and thermoplastics. Brass and bronze are corrosion-resistant to water, so many of the valves used in cold and hot water systems, and HVAC systems are made of brass or bronze. Brass is a forged material whereas bronze is a cast material, so while they have similar properties, and they are made through two different methods.

VALVE BODIES ARE COMMONLY MADE FROM:

Brass

Stainless steel

Bronze

Alloy steel

Cast iron

Thermoplastics

Steel

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VALVE SEALS

OTHER VALVE COMPONENTS ARE COMMONLY MADE FROM:

Thermoplastics

Glass

Resilient Material

Aramid Fiber

Graphite

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Valve bodies are commonly made from brass, bronze, cast iron, steel, stainless steel, alloy steel and thermoplastics. Brass and bronze are corrosion-resistant to water, so many of the valves used in cold and hot water systems, and HVAC systems are made of brass or bronze. Brass is a forged material, whereas bronze is a cast material, so while they have similar properties, they are made through two different methods.

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K N O WLE DGE CH EC K

What are the four main categories of valves?  Linear  Rotary  Check  Pressure Control

K N O WLE DGE CH EC K

What are three main functions of valves?  On/Off  Control  Backflow prevention

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KNO W LE DGE CH E CK

What are four types of valve connections?  Flanged  Threaded  Socket Weld  Butt Weld

KNO W LE DGE CH E CK

What are some of the materials used to make… Valve bodies?  Brass

 Stainless steel

 Bronze

 Alloy steel

 Cast iron

 Thermoplastics

 Steel Other valve components?

 Thermoplastics  Resilient Material  Graphite  Glass

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CRANE BRANDS

These are the trusted brands that makeup Crane ChemPharma & Energy, and while you may be familiar with some, you may not be as familiar with all, so we’ll go through each one now.

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CRANE BRANDS The portfolio of CRANE® brand valves today is focused on delivering value. With a complete range of bronze, cast iron, cast steel Gate, Globe & Check valves, resilientseated butterfly valves and ball valves, Crane has a valve for your needs. The Crane brand is synonymous with the company name. Crane was founded in 1855 but we didn’t start making our first valves until 1857 which were gate, globe, and check valves. Our long-standing history in this area of PROCESS FLOW TECHNOLOGIES has built a strong reputation in the marketplace. SO, it’s a brand that we still make and sell today and we now offer a complete range of bronze cast-iron, cast steel, gate, globe and check valves, butterfly valves and ball valves.

Aloyco® has supplied stainless and alloy steel valves for more than 70 years. The product line includes gate, globe, swing check, and ball valves in sizes ½” -24”, with flanged, socket weld, and threaded ends and pressure classes 150 to 600. Aloyco is a brand known for its stainless and alloy steel gate, globe and check valves, as well as ball valves, class 150 to class 600. These valves would not satisfy a cast steel need. They are made of stainless steel, specifically 304,3 16 stainless steel, or the alloy 20 types of stainless steel for more corrosive applications.

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CRANE BRANDS Center Line® has been a market leader in resilient seated butterfly valves for more than 40 years, and we have earned a reputation as a supplier of superior valves at competitive prices. Center Line® Series RS provides repeatable tight shutoff in severe abrasive, and corrosive environments. Center Line® 200 single-piece stem design assures even torque distribution and resilient seat provides positive shut off. The original Center Line was a 200 single-piece shaft. Then in 2001, the addition of Crane process flow technologies brought with it the Alpha Lavelle RS series, which was a Saunders product that we rebranded the Center Line RS and is manufactured in Sentara today. This particular valve is more applicable for severe, abrasive and corrosive environments than the Center Line 200, which is more for utility service.

The Noz-Chek® high-performance, non-slam check valve minimizes the damaging effects of water hammer in fluid systems and eliminates valve chatter associated with conventional valves in reciprocating compressor service. The flow area is designed to provide minimal pressure drop across the valve. Noz-Chek valves provide a quick dynamic response, reducing reverse velocity. Noz-Chek valves are high-performance, reverse-flow, non-slam check valves that feature the Venturi flow pattern for high-pressure recovery. It has the ability to shut instantaneously, which reduces the opportunity for water hammer.

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CRANE BRANDS A shorter face-to-face design for the nozzle check valve offers an economical alternative to fullbody with minimal sacrifice to performance es harSiz ace t 12” ri- s60” tisc c ASME B16.34 & API 6D, pressure classes 150 - 4500 API 6A pressure classes 2000 - 15000 Flanged, butt-weld ends, hub ends, and specials

Compac-Noz features check valves with a shorter face-to-face design which prevents full pressure recovery, but is lighter in weight since it does not have a full-length Venturi. This reduces the initial install cost, but not necessarily the total lifetime cost due to the increase in flow resistance.

Duo-Chek® valves have long been the standard for lowpressure drop flow reversal protection. These valves are made from cast iron, cast steel, stainless steel, and various exotic materials. Duo-Chek offers retainer less designs to API 594 endto-end dimensions in steel bodied wafer and lug style with a wide variety of trim materials, including both metal and resilient seats. Valves come in sizes up to 88” and pressure ratings up to class 4500. Duo-Chek valves have been the standard for low-pressure drop flow reversal protection, considered the double door flow reversal check valve. Originally branded Mission Valve, it is the originator of the duo check product line. They are manufactured in the design headquarters in Belfast, Northern Ireland, Chihuahua, Mexico, and Australia.

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CRANE BRANDS Flowseal® Butterfly valves define high performance. Soft Seat, Fire Flow®, Metal Seat, and Mil-Spec valves up to 48” in pressure classes 150, 300, and 600, wafer or lugged style that includes double dead-end service t.i syeal is a brand of double offset high-performance butterfly capaFbloilw valves. Offered in a soft seat, Fire Flow®, Metal Seat, and MilSpec valves up to 48 inches in pressure classes 150, 300, and 600 and in wafer or lugged styles.

Jenkins® valves are the choice for mechanical contractors in North America. The complete range of products, including 600 CWP-rated threaded and soldered end ball valves, make Jenkins the preferred supplier to this market place. Jenkins is the preferred choice for mechanical contractors in North America. Many of these valves are made of brass or bronze and include 600 CWP-rated threaded and soldered end ball valves.

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CRANE BRANDS

Krombach manufactures large fabricated butterfly valves, triple offset valves, and check valves. These valves range in size from 3” to 136” and are typically used in applications such as steam/water isolations, condenser isolations, cooling tower isolations, and seawater isolations. Krombach also makes soft seated and metal seated ball valves manufactured with precision to address rugged service in corrosive, abrasive, and hightemperature processes. Krombach was acquired in 2008 and manufactures large fabricated butterfly valves, triple offset valves, and a series of metal seated ball valves for specific rugged service applications, soft seated ball valves, and check valves.

Pacific® Valves pressure seal bonnet and bolted bonnet valves are ideally suited for high-pressure steam applications associated with power generation and refining. Pacific Valve solutions for HF acid service have been approved for both of the major licensors’ specifications for many years. Pacific wedge plug valves are chosen for delayed coker isolation in high-temperature slurry service. Pacific Valves are a line of pressure seal bonnet and bolted bonnet valves that are well suited for high-pressure applications associated with power generation and refining. The line also includes wedge plug valves for delay coker applications in high-temperature slurry service.

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INTRODUCTION

CRANE BRANDS Resistoflex® is the world's largest plastic-lined piping products supplier, with manufacturing and sales locations in North America, Europe, and Asia. Resistoflex invented the PTFE lined hose technology in 1953 for the aerospace and chemical industries and in 1956 introduced the world’s first pipe and fittings lined with Teflon® PTFE. We also offer a full line of pipe and fittings lined with polypropylene, Teflon® PFA, and Kynar® PVDF. Resistoflex doesn’t make valves, but they are the world's largest plastic-lined piping products supplier. They are known as the inventor of the PTFE lined hose technology and the manufacturer of the world’s first pipe and fittings lined with Teflon® PTFE.

The REVO® brand is the standard for excellence and performance in actuator technology and is widely recognized in the process industries as a leader in quality and innovation. The REVO® range of rack & pinion actuators is ideal for operating quarter-turn valves, especially butterfly, ball, and plug valves. The REVO brand is the standard of excellence and performance in actuator technology used to automate valves. These products are manufactured in Satara.

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CRANE BRANDS Saunders® has provided solutions in industries where resistance to corrosion, abrasion, contamination, and trouble-free operation are imperative. Simplicity in design coupled with over 75 years of cutting-edge innovation has resulted in the Saunders® diaphragm valve’s ability to handle a broader range of fluids than any other valve type. In addition, our core rubber and polymer technology competencies uniquely position us to truly manage ‘The Science Inside’ the valve. The Saunders diaphragm valve was invented by P.K. Saunders over 75 years ago, and today, the brand is still viewed as the leader in industrial diaphragm valves, as well as aseptic diaphragm valves.

Customers in North America know the Stockham® brand for their dependable quality bronze, cast iron, cast steel, ball, and butterfly valves. In Europe and Australia, the Stockham legacy brand goes hand in hand with CRANE® and Duo-Chek® on our wafer check valves. In North America, the Stockham has built a reputation on its dependable quality bronze, cast iron, cast steel, ball, and butterfly valves. In Europe and Australia, the Stockham legacy goes hand-in-hand with Crane and Duo-Chek on our wafer check valves.

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CRANE BRANDS Uni-Check® manufactures swing check valves that are compact, light-weight, and economical. These wafer check valves are preferred because of their compactness, ease of installation, and lower initial costs than traditional flanged swing checks. Sizes are available from 2” (50mm) to 36” (900mm), and pressure classes to meet ASME, BS, DIN, AS, JIS, and ISO standards. Various materials are available, including cast iron, cast carbon steel, and many alloy steels. These wafer check valves are available in sizes ranging from 2 inches to 36 inches, and pressure classes meet ASME, BS, DIN, AS JIS, and ISO standards.

WTA® designs, develops and manufactures a full range of high-quality Bellows Sealed Globe Valves, Strainers, Check Valves, Relief Valves, Change-Over Valves, and Special Valves meeting stringent specifications required by the Chemical and Petrochemical Industries. WTA manufactures bellows sealed globe valves for the most critical applications that require a tight seal. Other products from this brand include strainers, check valves, relieve valves, change-over valves, and special valves for the chemical and petrochemical industries.

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CRANE BRANDS Westlock is a global market leader in innovative and emerging technologies in the valve position monitoring, digital control & monitoring, and intelligent positioning serving the global oil & gas, chemical, petrochemical, and general industry markets. Products can be used in various applications, including oil, gas, chemical, petrochemical, and general industrial markets.

XOMOX® was established in 1956 as the Continental Manufacturing Company. The principal product was the Tufline® fluorocarbon-sleeved plug valve. The concept of the non-lubricated sleeved plug valve was developed owing to the advent of Teflon® by the E.I. du Pont de Nemours and Company. XOMOX, its original product was the Tufline fluorocarbon sleeved plug valve. The concept of the non-lubricated sleeved plug valve was developed owing to the advent of Teflon® by the E.I. du Pont de Nemours and Company.

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CRANE BRANDS Crane Fluid Systems is a leading brand of Crane Building Services & Utilities. A leading provider of valves, pipe fittings, and engineered products for CPFT applications in building services and general industrial markets. Crane Fluid Systems is leading brand of Crane building services and utilities operating in the UK and predominantly serving the British market. This brand has become the leading provider of valves, pipe fittings and engineered products for fluid handling applications in building services and general industrial markets.

NABIC has long been recognized as the industry standard for commercial and industrial hot water applications as one of the UK's leading suppliers of gunmetal safety values. Our valves are ideal for hot water supply, heating, pump relief, bypass relief, outside installation, and for use with complex gases and liquids. NABIC valves are manufactured under an ISO 9001 quality assurance system, designed and tested to the latest British Standards with the third party-certified discharge capacities, NABIC produces a pressure relief valve that has long been recognized as the UK industry standard for commercial and industrial hot water applications, specifically hot water supply, heating, pump relief, bypass relief, outside installation and for use with difficult gases and liquids.

Viking Johnson is a world leader in the manufacture and supply of couplings, flange adaptors, resilient seated valves, pipe repair, and jointing solutions for the international water, wastewater, gas, and industrial markets. Viking Johnson supplies couplings, flange adaptors, resilient seated valves, pipe repair and jointing solutions for the international water, wastewater, gas and industrial markets. 40

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CRANE BRANDS For over 100 years, the Hattersley brand has been synonymous with quality, reliability, and excellent service. Hattersley offers a vast range of ball, butterfly, check, gate, and globe valves. Where systems are designed for constant or variable flow, a range of commissioning valve solutions is available for flow or pressure balancing. The Hattersley brand caters to the building services and utilities, similar to Crane Fluid Systems, but targeting a different channel. It offers a vast range of ball, butterfly, check, gate, and globe valves.

Sperryn is a leading supplier of meter installation kits and emergency control valves for domestic, commercial, and industrial applications. Using the latest design facilities and technologies, Sperryn regulators offer increased capacity, accuracy, and lower pressure drops. Where applicable, fittings and control valves comply with the requirements of the relevant British Gas Engineering Standards. Sperryn gas controls is a leading supplier of meter installation kits and emergency control valves for domestic, commercial and industrial applications. Sperryn regulators offer increased capacity, accuracy and lower pressure drops.

The Triangle® brand of cast steel valves, originally from the UK, is now provided by our Sydney, Australia, site. Flanged and butt-weld cast steel multi-turn and swing check valves through 24” are available in pressure classes 150 to 600.

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SUMMARY VALVE A mechanical device that turns on and off regulates, modulates, or isolates the rate, volume, pressure, or direction of liquids, gasses, slurries, or dry materials through a pipeline, chute, or passageway.

FOUR CATEGORIES OF VALVES:  Linear  Rotary  Check  Pressure Control

THREE MAIN FUNCTIONS OF VALVES ARE:  On/Off  Control

 Backflow prevention

FOUR TYPES OF VALVE CONNECTIONS INCLUDE:  Flanged  Socket Weld 42

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 Threaded  Butt Weld |

VALVE & ACTUATOR OVERVIEW

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SUMMARY VALVE TRIM Collective name for the replaceable parts in a valve.

GASKETS Mechanical seals, or packing, used to prevent the leakage of a gas or fluids from valves.

VARIOUS VALVE MANUFACTURING MATERIALS:  Brass  Cast iron  Stainless steel  Thermoplastics  Graphite CRANE PROCESS FLOW TECHNOLOGIES

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 Bronze  Steel  Alloy steel  Resilient Material  Glass |

VALVE & ACTUATOR OVERVIEW

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SUMMARY

CRANE HAS A LARGE VARIETY OF BRANDS AND PRODUCTS.

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SUMMARY

DAY 1  Introduction  Linear Valves  Control Valves  Rotary Valves

DAY 2  Valve Testing  Actuators & Control Accessories  Valve & Actuator Sizing  Check Valves  Engineered Check Carlos Davila

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2 Valve & Actuator Online Training Module

Gate Valves

GATE VALVES

LEARNING OBJECTIVES At the completion of this lesson, you will be able to: 1. Given a picture of a gate valve, identify the major components. 2. Identify the following gate valve types: Wedge Parallel Slide Bolted Bonnet Pressure Seal Resilient Seated Knife Slab 3. Identify the three types of wedges.

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4. List advantages and disadvantages of gate valves. 5. Identify typical applications for gate valves. efine, “thermal binding.” 6. Define, 7. Define, “pressure locking.” 8. Identify three types of gate valve bonnets. 9. Identify at least one likely cause for each given problem associated with a gate valve. 10. Given a list of gate valves, identify the Crane brand or brands that manufacture each of them.

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MEET THE GATE VALVE INTRODUCING THE GATE VALVE

Simple construction On/Off operation Not recommended for throttling service High flow coefficient Easy to repair Heavy duty design

Featuring a heavy duty design, the gate valve is strictly used for on/off operation or isolation. Its construction is simple; gate valves are either open or closed. If ever left in the intermediate position, it would be destroyed, therefore, it is never used as a modulating valve, and it is not recommended for throttling service. Gate valves have a high flow coefficient, which refers to the flow capacity of the valve. When the gate within the valve is moved, a total opening is created which, allows the fluid to flow through quickly, however, there are gaps within the valve where the gate sits, and that reduces the flow coefficient (or Cv), thereby decreasing the flow. Therefore, gate valves do not have the highest Cv, like in ball valves, but they come close.

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GATE VALVES

MEET THE GATE VALVE

INTRODUCING THE GATE VALVE

Good for high temperature and high pressure service Bi-directional flow Easy & inexpensive to manufacture

Gate valves can withstand high temperatures and high-pressure service. They can manage flow that comes from either direction. And despite their heavy-duty design, they are easy and inexpensive to manufacture and can be used in many applications. Ultimately, the gate valve is a very robust product.

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GATE VALVES

MEET THE GATE VALVE VALVE MATERIALS AND TEMPERATURE LIMITS

1000ºF | 538ºC

500ºF | 260ºC

450ºF | 232ºC

CAST STEEL

BRONZE

IRON

Each of the materials used for gate valves can withstand different temperature limits. Cast steel has the highest threshold at 1000 degrees Fahrenheit. Bronze can withstand up to 500 degrees and Iron up to 450; as the temperature limits increase on each material, the pressure limits of that material decrease.

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GATE VALVES

VALVE COMPONENTS Handwheel Nut Gland Flange Packing Gland Packing Bonnet Bushing Stem T-Slot Disc Guide Body

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VALVE COMPONENTS Handwheel Gland Eye Bolts Bonnet Studs Bonnet Nuts Bonnet Gasket Bonnet Disc Seat Ring

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MEET THE GATE VALVE

KNOWLEDGE C HEC K

Take a few moments to match the name of each component to its location on the gate valve diagram.

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MEET THE GATE VALVE

STEM Bronze Stainless steel

DISC Bronze Stainless steel

SEATS

Inserted or machined into the body Bronze Stainless steel Stellite overlay

GATE VALVE TRIM Now we will explore the trim materials used in each part of a gate valve. The stem and disc of a gate valve could be trimmed with either bronze or stainless steel. As for the seats, they can either be inserted or machined onto the body. When a lower-cost bronze or brass is used, the seats would be machined as part of the body. When other bronze, stainless steel, or Stellite overlay is used, the seat will be replaceable as an insert.

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GATE VALVES

TYPES OF BONNETS

THREADED BONNET

The threaded bonnet is screwed into the

valve body with internal threads This is a “no maintenance” type of valve This the lowest cost valve

Now that you understand a gate value's makeup, let's the various bonnet connections, starting with the threaded bonnet. Threaded bonnets are the least expensive. They are considered a “no-maintenance” valve but are the least amenable to high-temperature swings.

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TYPES OF BONNETS

UNION BONNET

Connection provides external body

threads with a heavy duty nut Better for high temperature services Do not loosen up with temperature changes Stronger and more substantial product

The union bonnet connection provides an external body thread with a heavy-duty nut. Here, the bonnet remains stationary and does not turn. Instead, the union turns and holds the bonnet to the body. This is useful in screwed piping systems where a pipe is connected to a threaded pipe that can’t be turned. A union connection would come in handy, as it would be threaded into the pipe end on one side and the pipe itself on the other, allowing the user to pull the two pieces together. CRANE PROCESS FLOW TECHNOLOGIES

Unions are better equipped to handle high-temperature services and do not loosen with temperature changes; therefore they tend to be more costly than threaded bonnets. Typically, union bonnets can be found on smaller bronze and brass type valves in critical services, involving applications that could seriously endanger people or property should there be a piping or valve failure. The same applies to bolted bonnets and pressure seal bonnets.

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TYPES OF BONNETS

BOLTED BONNET

Bonnet is attached to the body

using bolts Joint has a gasket Strong and easy to assemble

and disassemble

The bolted bonnet is connected, or attached, to the body with a gasket and either studs and nuts or bolts and nuts, hence its name, making it a sturdier design than the threaded connection. However, it’s extremely important that the bolts must be tightened correctly, especially when disassembling and reassembling, to avoid leakage.

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GATE VALVES

TYPES OF BONNETS

PRESSURE SEAL BONNET

Incorporate “Bonnet take-up bolts” to pull

the Bonnet up and seal against the pressure seal gasket. Body-Bonnet joints seal improves as the

internal pressure in the valve increases.

The fourth type of bonnet is the Pressure Seal Bonnet. This type of connection incorporates “bonnet take-up bolts,” which are used to pull the bonnet up and out and seal against the pressure seal gasket. As a result, the pressure inside actually pushes the bonnet tighter into the seat, and the seal is at a bevel.

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GATE VALVES

TYPES OF GATE VALVES 1. 2. 3. 4. 5. 6. 7.

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Rising / Non-Rising Stem Wedge Parallel Slide Bolted Bonnet Resilient Seated Knife Slab

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RISING / NON-RISING STEM In a gate valve with a rising stem, the stem goes up and down with the disc and gate when moving from the closed position to the open position. So if the gate is up, it’s easy to tell it’s open because the threads are exposed. In a non-rising stem valve, the threads on the stem are actually threaded into the gate, so the valve stem opens, the gate is pulled up, but the stem doesn’t move, hence its name. The stem is literally threading into the gate itself rather than rising. Note some of the differences between the two designs: the rising stem valve requires more clearance to accommodate the stem in the open position, while in the non-rising stem design, the threads may suffer from corrosion and/or wear and tear as they are exposed to the medium.

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WEDGE

Yoke Gland

Stuffing box (packing)

Bonnet

Wedge

Seat Ring

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TYPES OF WEDGE

SOLID WEDGE A solid wedge valve is smaller at the bottom than the top; this is the most accessible type to manufacture.

FLEX WEDGE

SPLIT WEDGE

A flex wedge is connected as one piece, but it has an opening around the outside, so it provides some level of flexibility that allows it to match the body seat.

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A split wedge is two different wedges that somewhat float, so they can best to match the body seat.

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GATE VALVES

SPLIT WEDGE

Locking Pin

Ring - 2 x ½

Back Seat

Central part

Wedge plate lens

SPLIT WEDGE Literally two halves that are connected.

Bayonet Lock 64

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SPLIT WEDGE

Wedge Plate with Bayonet Lock

When the two plates lock into place, the two discs end up floating. A split wedge is self-adjusting and selfaligning to both seat's sides. Therefore, disk flexibility is inherent to the split wedge design. This flexibility allows the split wedge to seal more easily, and reduces stickiness between the sealing surfaces.

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PARALLEL SLIDE

Now we will move on to the next type of gate valve, the Parallel Slide. In this type of valve, the seats themselves are parallel, and the slide gate. There are also pressure-assisted springs that provide the initial sealing load and push the seat downstream into the disc and into the seat, so that the higher the pressure, the tighter the seal.

DESIGN PRINCIPLE

Inner-gate space becomes pressurized

This diagram gives you some indication of a parallel slide’s design principle and how it works. The initial seal is positive with springs, but then the pressure pushes this gate towards the seat, providing the stronger seal.

Forces disc against seat face

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WEDGE VS. PARALLEL SLIDE WEDGE GATE VALVE

PARALLEL SLIDE GATE VALVE

Seal by Applied Force* Two Sided Sealing Large Actuator Required to Open and Close Valve * EMO-utilize torque switch MSS SP61 Permits Leakage

TORQUE SEATED

Seal by Position * One Sided Seal 30% Smaller Actuator *EMO-utilize limit switch Capable of Zero Leakage

POSITION SEATED

FORCE

In a wedge gate valve, the wedge seal is applied by force, so if the thrust is lost, so is the seal. Whereas in a parallel slide gate valve, the seal is determined by the position of the gate. Also, the wedge gate valve has a two-sided seal, while the parallel slide gate valve is only sealed on the downstream gate.

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In a wedge valve, a larger actuator is needed to open and close the valve to maintain the seal's force. Still, a smaller actuator is needed in the parallel slide since the seal doesn’t require any thrusting or pushing. Lastly, the wedge gate valve is designed to MSS standards that permit a certain amount of leakage, but the parallel slide gate valve is capable of zero leakage.

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BOLTED BONNET

Leak path

This design requires a gasket to seal the joint between the body and the bonnet. In this valve, the bonnet acts against the forces trying to leak. Bolted bonnets are generally used to provide sealing in larger valves and higher pressure applications.

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PRESSURE SEAL BONNET

PRESSURE SEAL GASKETS

For pressure classes greater than 600, Crane recommends using the pressure seal bonnet. You can see that bolts provide the initial seal, and as pressure increases, the bonnet gets pushed out and wedges the seal tighter against the body.

Here you can better see how the arrangement would move up as pressure increases. The thrust ring and segment ring hold everything in place as the pressure provides the seal.

Draw Bolt Collar

Segment Ring Body Thrust Ring Gasket Bonnet

25o

Point formed in the bonnet of the PV Pressure Seal valve.

23.5o 15o

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RESILIENT SEATED GATE VALVE The resilient seated valve is suitable for water, neutral liquid and sewage applications. This is a valve that Viking Johnson would have manufactured for use with their pipe plant connectors for water and wastewater service. Seawater versions are also available with a special trim to combat the corrosive seawater.

Suitable for use with water, neutral liquids and sewage Clockwise or anti-clockwise closing Handwheel option Sea water version

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KNIFE GATE VALVE They typically work well in slurries because as the gate closes, the knife will cut the slurries. In a paper mill, the valve cuts the pulp. These valves are available in a broad range of sizes and can be bi-directional or uni-directional.* *Crane does not make this product.

Good for slurries Broad size range High Cv Bidirectional or unidirectional available Not a Crane product

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SLAB GATE VALVE Also known as the through conduit gate valve, these valves are typically used in oil and gas applications. When in the open position, a through port is created. But unlike a wedge gate or parallel slide gate, there’s no gap because the slab fills that gate. Instead, a port opening in the slab lines up with the seats so that when the valve is in the fully open position, it’s as though it’s an extended section of the pipeline. Slab gate valves, therefore, have the highest flow Cv rating possible. Also, since slab gate valves don’t have a gap, they are considered piggable, meaning they can allow for the line to be cleaned by small devices known as pigs. Today, more sophisticated pigs have electronic sensors that can determine whether there is corrosion in the pipeline, basically by detecting thin areas. Some valves are considered pig launchers, and some are pig receivers. Crane doesn’t actually make the pigs, but if there is a valve in the pipeline that has to be piggable, it needs to be a full port valve so that it does not get stuck in the gap.

Also called Through Conduit Used for oil and gas Good flow Piggable

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KNO W LE DGE CH E CK

What are four types of gate valve bonnets?  Bolted  Threaded  Union  Pressure Seal

KNO W LE DGE CH E CK

Can you name three types of gate valve wedges?  Solid  Flex  Split

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GATE VALVES

ADVANTAGES & DISADVANTAGES Gate valves can be used for a wide range of on-off applications where high Cv or Kv is needed. This is because they have very high flow coefficients, and specifically, with the parallel slide gate valves, they can be operated with a lower thrust. On the other hand, gate valves are unsuitable for throttling applications, except for specially designed knife gates. Another disadvantage is that they are challenging to automate and require an actuator with the same amount of stroke as the valve. However, this can add to the weight and size of the valve, requiring additional support and costs.

ADVANTAGES FOR GATE VALVES

DISADVANTAGES FOR GATE VALVES

Wide range of on/off applications where high Cv or Kv is needed Lower thrust required to operate (Parallel Slide)

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Not suitable for throttling applications except for specially designed knife gates Potential for thermal binding in high temperature applications (Solid Wedge) |

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GATE VALVES

APPLICATIONS SOLID WEDGE

Isolation in process applications, potable water, and other liquid systems

FLEX WEDGE AND SPLIT WEDGE

High temperature/pressure steam and water in power plants Where thermal binding is a concern PARALLEL SLIDE

High temperature/pressure steam and water in power plants where tighter sealing is needed

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APPLICATIONS SLAB GATE VALVE

Isolation in process applications, potable water, and other liquid systems The slab gate valve seals with springloaded seats or a split wedge design and is therefore used in oil and gas platforms and pipelines, especially those that utilize pigs.

KNIFE GATE VALVE

Low temperature and pressure Pulp and paper and Oil Sands Slurries, sludge, sewage Knife gate valves are best suited for lowtemperature and low pressure applications, like pulp and paper, oil sands, slurries, sludges, and sewage.

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KNOWLEDGE CHECK

Can you identify the following valves?

Bolted Bonnet

Wedge

Knife

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Parallel Slide |

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Slab |

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GATE VALVES

THERMAL BINDING D E FI NI TI ON

THERMAL BINDING Thermal binding takes place when a valve cools and the body shrinks more than the seated disc. The disc becomes, “bound” and may remain unserviceable until high temperature is re-obtained.

Thermal binding occurs when a valve cools, and the body shrinks more than the sealed disc. The disc becomes bound and may remain unserviceable until the high temperature is re-obtained. So, picture an escape valve that is running hot steam through it. As the valve is closed, the outside radiates away that heat, but the inside is still hot because the fluid in it is hot. The valve contracts around the seat, binding it up and allowing the valve body to cool faster than inside the gate. The body shrinks or cools around the valve. That's thermal binding.

EXAMPLE OF THE THERMAL BINDING PROCESS The body has shrunk more than the disc. When thermal binding has occurred, the valve can remain unserviceable until a high temperature is re-obtained (recommended ∆T ≤150°). One thing to note though is that parallel slide gate valves are not subject to thermal binding.

Thrust required to lift wedge

Thermal binding load

FLOW

Upstream

Downstream

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THERMAL BINDING

Preventing thermal binding

After closing the valve, back off the stem a ¼ of a turn to allow for stem expansion Install a bypass pipe and valve on the inlet and outlet sides of the body. This will allow warm up of both sides of the wedge So how can we prevent thermal binding? After the valve is closed, the stem can be backed off so that it can expand. A bypass pipe and valve are also installed on the inlet and outlet sides of the body. Then, when it needs to be opened, some hot fluid will start to circulate and warm the body, returning it to its normal state. That’s when the disc will open. So, this bypass line would go from the upstream side to the downstream side. That’s when the bypass loop can be opened to allow the steam to start flowing to heat up the entire valve. The valve is then equalized, and its temperature normalized, eliminating thermal binding.

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PRESSURE LOCKING

Higher bonnet pressure causes the body to expand, moving the seats apart. The stem pushes the disc further down and it “locks” into the seat.

Here you can see what that would look like. As pressure increases in the bonnet area, the body expands, moving the seats apart. That force then becomes more than what the actuator was sized for, so it can now be opened. The stem then pushes the disc further down, and locks into the seat.

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PRESSURE LOCKING Solutions:

Cycling the valve during start-up Installing a pressure release system on the body cavity Installing an automatic relief valve or a manual drain Drilling an internal hole in the wedge face

Here you can see what that would look like. As pressure increases in the bonnet area, the body expands, moving the seats apart. That force then becomes more than what the actuator was sized for so it can now be opened. The stem then pushes the disc further down and it locks into the seat.

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GATE VALVES

PROBLEMS AND CAUSES VALVE DOESN’T OPEN OR SHUT ON DEMAND Physical blockage, corrosion, broken actuator, broken stem, pressure locking, thermal binding The valve doesn’t open or shut on demand. This will occur if there is physical blockage, corrosion, a broken actuator, a broken stem, pressure locking, or thermal binding occurring.

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VALVE PARTIALLY STROKES BUT DOESN’T REACH DESIRED POSITION Excessive stem load due to packing or seat friction, high stem to stem-nut friction, actuator problems This could be a result of excessive stem load due to packing or seat friction. If the packing is set incorrectly, but the user continues to try packing it down the valve can easily lock up. The friction from the stem packing to the stem is so high that it would prevent the valve from moving, which is called excessive stem load due to packing. Other causes include seat friction if there are two materials that are similar in makeup, or there could be actuator problems.

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GATE VALVES

PROBLEMS AND CAUSES PACKING LEAKAGE

BODY TO BONNET LEAKAGE

Normal packing wear, incorrect packing set, inadequate packing consolidation.

Wrong bolt torqueing, scratched sealing surface, wrong seal used, seal not properly installed.

Packing leakage is often caused by inadequate packing consolidation where all of the packing rings are inserted and compressed simultaneously rather than a few at a time from the bottom up. When done all at once, the result is only a few of the rings are compressed, and when tightened, leakage will ensue over time. To avoid this, it’s important that the IOM is followed which provides detailed assembly instructions on how to repack the valve for the particular type of packing in use.

Body to bonnet leakage is often caused when the wrong bolt torque is used for the gasket type. This is why it’s so important that the proper assembly instructions and the installation and maintenance instructions are followed.

SEAT LEAKAGE Foreign material, seat/disc damaged, seat/disc repaired wrong, insufficient stem thrust. Seat leakage is the next problem which is frequently caused by foreign material. When plants are built, there is often leftover welding debris, welding rot, or other unexpected objects, like gloves that are left in the pipeline by mistake. When the piping system starts up, those objects, if not caught by the filter, could end up in the valve, damaging it or scratching the surface of the sealing material. CRANE PROCESS FLOW TECHNOLOGIES

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GATE VALVES

PROBLEMS AND CAUSES

PRESSURE LOCKING

THERMAL BINDING

Pressure between discs or in bonnet much higher than up or downstream

Differential expansion and contraction between disc and body

We defined pressure locking earlier, which occurs when the pressure between discs or in the bonnet is higher than it is up or downstream.

Thermal binding is caused by differential expansion and contraction between the disc and body, and to relieve it, and the temperature must be equalized.

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GATE VALVES

PROBLEMS AND CAUSES EXCESSIVE PACKING FRICTION

BENT OR BROKEN STEM OR DISC ATTACHMENT

Over tightened packing gland nuts, cocked packing gland follower.

Excessive closing force applied, weaklink design calculation wrong. The last problem we’ll discuss is a bent or a broken stem. Here, if the actuator is sized too large for the valve, the disc or stem could be bent or broken during an excessive thrust. Once that stem is bent, it won’t rise and fall through the packaging as effectively.

Excessive packing friction results from over-tightened packing gland nuts or a cocked packing gland follower.

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3 Valve & Actuator Online Training Module

Globe Valves

GLOBE VALVES

LEARNING OBJECTIVES At the completion of this lesson, you will be able to: 1. Given a picture of a globe valve, identify the major components. 2. Identify the following gate valve types: T-Pattern Y-Pattern Angle Bellows Sealed Change-Over 3. Identify three trim characteristics of a globe valve disc. 4. HiIdentify three types of guiding for valve discs.

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5. List advantages and disadvantages of globe valves. 6. Identify typical applications for globe valves. 7. Given a list of globe valves, identify the Crane brand or brands that manufacture each of them.

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GLOBE VALVES

MEET THE GLOBE VALVE INTRODUCING THE GLOBE VALVE

Called a globe due to round body shape Heavy duty design Easy to repair Good for high temperature and high pressure service Unidirectional flow Can be used for regulating or throttling

A globe valve is a linear motion valve that is primarily designed to stop, start and regulate flow, so it is considered a control valve. It gets its name from its shape which, is round like a globe. They are generally easy to repair and have a CRANE PROCESS FLOW TECHNOLOGIES

unidirectional flow featuring packing glands on the shaft. Similar to the gate valve, globe valves are metal-to-metal seated, making them appropriate for high temperature and high-pressure service.

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GLOBE VALVES

MEET THE GLOBE VALVE

INTRODUCING THE GLOBE VALVE

Used for on/off service Main type of control valve Poor flow path Generally not made in large sizes

The fundamental principle of the Globe Valve operation is the perpendicular motion of the disc away from the seat ensuring that the ring-shaped space between the disc and seat ring gradually close as the Valve is closed. This property gives a Globe Valve reasonably good throttling capability.

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The disc of a Globe Valve can be totally removed from the flow path, or it can completely close the flow path. However, globe valves feature a poor flow path characterized by multiple twists and turns that can present lots of turbulence and slow the flow, resulting in energy loss. Additionally, globe valves are offered in a smaller size range than others like the gate valve.

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GLOBE VALVES

VALVE COMPONENTS Handwheel Nut

Handwheel

Yoke Bushing

Gland Flange Gland Eye Bolts

Gland Packing

Bonnet Studs

Bonnet Bushing

Bonnet

Stem

Disc

Disc Stem Nut

Seat Ring Body A globe valve's components should look familiar, as the top works can also be found on a gate valve. The stem diameter might be different so that the sizing might be as well, but essentially the components are the same. The key difference here, though is that a globe valve has a disc and one seat ring, whereas gate valves have two seats and a wedge. CRANE PROCESS FLOW TECHNOLOGIES

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VALVE & ACTUATOR OVERVIEW

GLOBE VALVES

MEET THE GLOBE VALVE

KNOWLEDGE C HEC K

Take a few moments to match the name of each component to its location on the globe valve diagram.

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GLOBE VALVES

VALVE TYPES

T-Pattern Y-Pattern Angle Bellows Sealed Change-Over

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GLOBE VALVES

T-PATTERN

Most control valves are T-Pattern Tight shut-off Used for equipment isolation Many options available

In general, control valves are considered T-Pattern valves. We’ve discussed the complex flow path of globe valves which is a benefit when it comes to controlling valves, as the idea is to slow down, restrict and control the fluid. T-Pattern valves also allow for tight shut-off, which makes it ideal for equipment isolation which facilitates maintenance, allows for the removal of equipment, and enables a plant shutdown when needed.

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GLOBE VALVES

Y-PATTERN

More compact than T-Pattern Smoother flow pattern (better Cv/Kv)

The Y-Pattern valve is the next type we will discuss. These valves are more compact in design but also feature a smoother flow path, allowing for a higher flow coefficient (Cv). The benefit is that the valve doesn’t have to be very large to have a decent flow capacity, unlike if a T-pattern valve is used. The smaller the valve, the less material used to make it and the less it weighs, making it less expensive than a T-pattern valve.

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GLOBE VALVES

ANGLE

Ports are 90 degrees Offset Fewer Flow Stream Direction Changes Higher Capacity Cavitation & Flashing Service

This glove valve gets its name from its 90-degree offset ports. Unlike the T valve which, has a complex flow path, the flow in an angle valve can only make a right-angle turn and can therefore only change directions once, giving it a higher flow capacity. It also has a lower pressure drop making it the go-to valve for use with media that has a propensity for flashing or cavitation.

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GLOBE VALVES

BELLOWS SEALED

For different types of media with inflammable, explosive, volatile, toxic, or aggressive characteristics, whose delivery must be prevented into the atmosphere Designed in accordance with the Federal Emission Protection law

The bellows sealed globe valve is ideal for explosive, volatile, and or toxic media that absolutely must be contained. Therefore, it was designed in accordance with the Federal Emission Protection Law. Unique designs of this valve are also offered for critical applications like chlorine service and phosgene service and for use with hot thermal oil that runs the risk of flashing and burning if exposed to the atmosphere at high temperatures. Crane‘s WTA brand manufactures this valve, and its name in German means "valve for hot oils.“

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GLOBE VALVES

BELLOWS SEALED

Two-part rising stem Stem coupling with bellows Anti-torque device and position indicator Full-size safety gland packing

Bellows sealed globe valves have a twopart rising stem coupled with the bellows an anti-torque device and a position indicator. Therefore users should be careful to pull and push the bellows rather than twist them to prevent stem rotation. 98

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GLOBE VALVES

BELLOWS SEALED

Metal back seat with stroke limiter in open position Bellows anti-vibration device

Multiple wall Fully flushed stainless steel bellows Designed for 10,000 cycles Fully welded

Bellows sealed globe valves also feature a metal backseat, which is another type of seal, and a stroke limiter. In addition, they have multiple walls that are designed for 10,000 cycles and typically come with a backup packing seat. CRANE PROCESS FLOW TECHNOLOGIES

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GLOBE VALVES

CHANGE-OVER

Extremely low resistance coefficients Compact weight-saving construction method Offered in carbon steel, stainless steel, Low temperature carbon steel, and special materials

The next type of valve we will review is the change-over globe valve which is used in conjunction with the pressure safety relief valve. They are typically used in continuously operating systems, as they allow the pressure relief valve to be changed and calibrated without shutting down the system. This valve has full flow access as its shifting over a safety relief valve. Then when it’s fully shifted over, the valve can be shut off and removed, but the system is still completely protected.

Change-over valves are compact, lightweight, and offered in various materials.

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GLOBE VALVES

CHANGE-OVER

Plants are protected against undue excess pressure by switching over to the relevant standby safety valves Full blow off capacity is maintained during switching Hand wheels linked for tandem use by chain

Manufacturing plants are protected against undue excess pressure by switching over to the relevant standby safety valves. Full blow-off capacity is maintained when the change-over valve switches from one side to the other. When using changeover valves in tandem, both hand wheels are linked via a chain wheel to assure simultaneous operation

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GLOBE VALVES

DISC TRIM CHARACTERISTICS Three common trim characteristics:

QUICK OPENING

LINEAR

EQUAL PERCENTAGE

Now that you understand the types of globe valves, we’ll move on to their three common trim characteristics: quick opening, linear and equal percentage. These affect the flow characteristic of the valve over the range of the disc’s movement. The flow characteristic is the relationship between the stem travel, expressed in percent of travel, and the flow of the fluid through the valve expressed in percent of full flow.

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GLOBE VALVES

DISC TRIM CHARACTERISTICS QUICK OPENING

Maximum flow as soon as stem starts to open

The quick opening trim characteristic allows for the maximum possible flow as soon as the stem starts to move from a closed position. This characteristic is usually selected for two-position rather than modulating valves.

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GLOBE VALVES

DISC TRIM CHARACTERISTICS LINEAR

Equal volume and lift changes

The linear trim characteristic offers equal volume and lift changes. If plotted on rectilinear coordinates, this flow-lift relationship approximates a straight line, giving equal volume changes for equal lift changes, regardless of percent of valve opening. In short, the flow is going to change linearly to the movement.

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GLOBE VALVES

DISC TRIM CHARACTERISTICS EQUAL PERCENTAGE

A valve with an equal percentage characteristic, like movements of the valve stem at any point of the flow range, changes the current flow by an equal percentage regardless of the existing flow. In short, each movement of the stem will result in an equal percentage change in output. Equal percentage discs are especially useful for control jobs where occasional wide variations in loads occur. CRANE PROCESS FLOW TECHNOLOGIES

Like movements of the stem at any point of flow changes the flow an equal percentage

Example: Suppose a valve stem has been lifted 30% of its total lift, and the flow at this time is 3.9 gal/min. Now assume that the valve opens an additional 10% of its total travel and that the flow increases to 6.2 gal/min or a 60% increase. Next, suppose that the valve stem moves an additional 10% so that it is now 50% open. The flow now will be 10 gal/ min, or another 60% increase in flow.

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105

GLOBE VALVES

DISC TRIM CHARACTERISTICS 100

Pe Eq rc ua en l ta ge

Q Op uic en k in g

% FLOW

ea n Li

% VALVE TRAVEL Here you can see all three globe valve flow characteristics and valve travel from 0 to 100%. As the names of each imply, the quick opening opens quickly. The travel in the linear is indeed linear, and an equal percentage, there is an equal change in the opening as the fluid moves through it. So based on the amount of control needed and the media involved, the valve trim can be selected based on one of these different flow characteristics.

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100

GLOBE VALVES

GUIDING

CAGE

POST

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STEM

VALVE & ACTUATOR OVERVIEW

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GLOBE VALVES

CAGE GUIDING

Most common Best plug support Potential for galling More friction Not recommended for dirty fluids

Cage guiding is the most common and is used in severe service control. As the flow goes through the cage, there are multiple steps the flow must go through. Each of those steps takes a pressure drop which moves it from high pressure from the inlet side to low pressure on the outlet side. This occurs gradually and prevents cavitation.

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GLOBE VALVES

POST GUIDING

Guiding is near disc Smaller bearing surface More deflection Better in dirty fluid

The post guiding is guiding on the post near the disc. It generally has a smaller bearing surface. This guiding type has more deflection, and is typically better suited for dirtier services than cage guiding because it doesn’t have as tight of tolerance and the bushing somewhat wipes the media away.

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GLOBE VALVES

STEM GUIDING

Two stem bearings Cantilevered plug Low friction No galling Recommended for dirty fluids Can have plug vibration

Stem guiding is the third type. Here you can see the stem with the cage. This feature offers limited opportunity for galling but from a control standpoint, it dangles in the media, causing potential vibration. This depends on the flow and other media characteristics.

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GLOBE VALVES

ADVANTAGES & DISADVANTAGES

Short stroke enhances process control capability Selectable trims to optimize control T-Pattern Lowest Cv Traditional design Angle Pattern Higher Cv Used where change of direction is desired Y-Pattern Highest Cv The T pattern has a low Cv and is the traditional design for control valves.

Short stroke enhances process control capability. So, the valve can make small movements which change the flow characteristics making it a good control valve.

The Angle pattern has a higher Cv and is used when a change in direction is desired.

Selectable trims optimize how that output looks to the input.

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The Y pattern has the highest Cv and is used for on-off applications. |

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GLOBE VALVES

APPLICATIONS

Throttling and flow regulation in a variety of fluid systems Wide range of temperatures and pressures Generally used for clean fluids Angle Pattern used where change of direction is desired

Globe valves are used in many of applications, including throttling and flow regulation of various fluid systems and applications with wide temperature ranges. In addition, angle patterns are used for clean fluids where a change in direction is required. Also, Globe valves are generally easier to automate for on-off functionality.

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GLOBE VALVES

KNOWLEDGE CHECK WHAT ARE THREE TRIM CHARACTERISTICS?

Quick Opening Linear Equal Percentage

CAN YOU NAME THREE TYPES OF GUIDING?

Cage Post Stem

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GLOBE VALVES

KNOWLEDGE CHECK Can you name five types of globe valves?

T-Pattern

Y-Pattern

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VALVE & ACTUATOR OVERVIEW

GLOBE VALVES

KNOWLEDGE CHECK

Angle

Bellows Sealed 5

Change-Over

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VALVE & ACTUATOR OVERVIEW

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4 Valve & Actuator Online Training Module

Diaphragm Valves

DIAPHRAGM VALVES

LEARNING OBJECTIVES At the completion of this lesson, you will be able to: 1. Given a picture of a diaphragm valve, identify the major components. 2. Identify two types of diaphragm valves. 3. List the materials available for diaphragm construction. 4. Identify the available linings for Crane diaphragm valves. 7. Identify at least one likely 5. List advantages and cause for each given disadvantages of diaphragm problem associated with a valves. diaphragm valve. 6. Identify typical applications 8. Given a list of diaphragm for diaphragm valves. valves, identify the Crane brand or brands that manufacture each of them.

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DIAPHRAGM VALVES

HISTORY

Invention of the diaphragm valve: We’ll first start by reviewing the history of the diaphragm valve. In 1928, a man named P.K. Saunders was working in a South African mine. He conceptualized the design of the valve after watching someone step on a process hose and noticing how the flow stopped. He realized he could develop a valve version of that action that would close off a line, and the diaphragm valve was born.

Invented in 1928 by P.K. Saunders Main facility opened in 1939 in Cwmbran, South Wales

In 1939, he opened a facility in Cwmbran, South Wales that, would serve as the primary manufacturing facility for the Saunders Industrial Diaphragm Valve, and that building still stands today. CRANE PROCESS FLOW TECHNOLOGIES

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DIAPHRAGM VALVES

MEET THE DIAPHRAGM VALVE

Diaphragm Valve

Diaphragm

Named for its crucial component The diaphragm valve gets its name from its most crucial component, the diaphragm, which serves as a closure element.

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DIAPHRAGM VALVES

MEET THE VALVE

100% leak tight Working parts are isolated Wide choice of: body materials diaphragms lining options end connections Yellow indicator with lip seal Lubricated for life

The diaphragm valve is 100% leak-tight, and the working parts are isolated from the media. Within the valve, Acme threads drive the compensator which pushes on the diaphragm. The diaphragm seals at the bonnet so that the media is sealed off from the working elements of the valve, unlike with the gate valve where the stem is in the media. There are a wide variety of body materials, diaphragms, lining options, and end connections for the diaphragm valve. In terms of lining options, rubber is used and can cover all the parts of the body that come into contact with the media. However, various liner materials can be used according to the media involved, and the body becomes the armor, or strength, to provide pressure resistance. Without that armor, the lining would expand and burst like a balloon. The lining can provide corrosion resistance, as well. Rubber is one material that is often used, as it works well in slurry applications due to the solid particles in the media. Teflon, a registered trademark of Dupont, is another liner for other applications, as the PTFE or PFA offers corrosion resistance. CRANE PROCESS FLOW TECHNOLOGIES

Let’s take a moment to review PTFE and PFA in detail. PTFE is the descriptor for regular Teflon, whereas PFA is the moniker for the generic term for a mount processable Teflon. This means it can be heated and become extrudable without burning or vaporizing. It becomes a liquid and then can be extruded into a mold. PTFE, however, is not melt-processable, so it is used to form a shape which is then put into an oven to become the final element. Once heated and formed, PTFE cannot melt again in the presence of heat. It will continue to heat up and become softer but will not return to a liquid state. Returning to the diaphragm valve components, the final two features I want to point out are (1) this valve is lubricated for life. And (2) it has a yellow indicator with a lip seal. This image shows that it’s open because you see yellow. However, if the yellow cannot be seen, that means the valve is closed.

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DIAPHRAGM VALVES

MEET THE GLOBE VALVE

Position Indicator Bonnet Diaphragm Compressor This valve has only five main components: the position indicator, the bonnet, the diaphragm, which is the major component of the valve, the body, and its liner, and the compressor. The compressor looks like a disc or gate and pushes on the diaphragm, compressing it into the body.

Liner

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DIAPHRAGM VALVES

KNOWLEDGE CHECK

KNOWLEDGE C HEC K

Take a few moments to match the name of each component to its location on the diaphragm valve diagram.

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DIAPHRAGM VALVES

VALVE TYPES

Weir

Versatile & extensively used in Industrial applications Can handle up to 15% solids Perfect for on/off control involving corrosives

We’ll now review the different types of diaphragm valves. The first is the weir type. The best way to remember how this type of valve works is to think of a weir on the side of a dam. If the water rises, it doesn’t breach the dam because it goes over the weir and around it. This valve type has a similar concept and shape. As the flow of media rises, it goes up and around the weir. Weirs are versatile re-duced-floe valuves and extensively used in industrial applications, especially on/off control applications involving corrosives.

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DIAPHRAGM VALVES

VALVE TYPES

Fire Hydrant

Bubble tight shut off Fire tested and approved with the world’s leading safety agencies For use on cruise liners, oil tankers, naval vessels and firefighting equipment in oil refineries

The second type of Diaphragm valve is the Fire Hydrant which features a bubble type shut-off. Unlike with other valves where the torque builds up if it sits for a some time, in fire hydrant valves, the torque remains the same at all times. So even if the valve sits without use for a year or so, it will operate upon start up with no issue or corrosion. It is a robust valve that has received the approval of agencies like Lloyd’s of London for shipping and other certifications for shipboard use on cruise liners and oil tankers for their fire systems. CRANE PROCESS FLOW TECHNOLOGIES

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DIAPHRAGM VALVES

VALVE TYPES

Straight Through

Low pressure drop Smooth flow ideal for slurries

The following valve we will discuss is the straight-through valve. These valves have a small weir, and the compressor is very long because it has to push that diaphragm through the full stroke or the full port opening of the valve. This valve works well in slurry applications with up to 15% solids.

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DIAPHRAGM VALVES

VALVE TYPES

HC4 - Aseptic

Class leading platform of Forged 2 Way , Standard Machined Block and Custom Designs to meet increasing demands for hygienic performance and regulatory compliance in Life Science process and utilities

HC4 Aseptic Valves are the next diaphragm valve type. We offer a class-leading platform for these valves that are manufactured in the new plant in Satara. These valves are typically used in aseptic and pharmaceutical applications which, require tight control of any contaminants that could interfere with the new media that is being developed or grown as part of the biopharmaceutical process.

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DIAPHRAGM VALVES

DOUBLE ACTING STEM

On the full flow version of a throughport diaphragm valve, the stem itself is double-acting As the stem turns, it moves up, but it’s also threading into the compensator, similar to a non-rising stem, but with both actions occurring. So, each turn produces twice the action, requiring fewer turns to create a full movement when operating the valve.

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DIAPHRAGM VALVES

DIAPHRAGM MATERIALS Desired properties of a diaphragm

High flex performance Good compression set properties Chemical resistance Abrasion resistance Anti-aging

There are specific properties of a diaphragm that are important for proper performance. High-flex performance, for example, is critical. Also, good compression set properties, chemical resistance, abrasion resistance, and anti-aging are desired properties of a diaphragm.

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DIAPHRAGM VALVES

DIAPHRAGM MATERIALS

Traceable multi layers of rubber and nylon reinforcement

Studs attached with bonding adhesive and mechanical anchorage

Rib around port area and across weir for leak tight sealing and lower closure torque Here you can see a typical diaphragm with rubber and nylon reinforcement layers that provide the rigidity to withstand pressure and maintain the flexure needed to be able to seat. There are also studs attached with bonding adhesive and mechanical anchorage. The threaded stud is used on the resilient elastomer type of diaphragm. Ribs around the port areas and across the weir provide leak-tight sealing and low closure torque.

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DIAPHRAGM MATERIALS Diaphragm materials & life expectancy

10 Years E3, 425 (EPM) 226 Fluoroelastomer (Non FDA) 214S & 214 with EPM Backing

7 Years Butyl, Nitrile & Neoprene 5 Years Natural Rubber type of diaphragm material, our sellers and customers can be better informed when selecting the best material for their application based on how long they need it to work without a replacement part.

Let’s now review the various diaphragm materials. Elastomers, generally, have a defined life expectancy that ranges from 5 to 10 years depending on the material. Those that fall in the 10-year category include EPM, fluoroelastomer which, is a type of Teflon, and EPM backing. The 7-year category includes nitrile, butyl, and neoprene, while natural rubbers fall into the 5-year category. By understanding the life expectancy of each

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When customers receive a replacement diaphragm, the product arrives in a sealed container with a UV protective covering to prevent light and oxygen exposure extending its shelf life.

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DIAPHRAGM VALVES

DIAPHRAGM MATERIALS

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75 years of history and experience Began rubber processing in 1932 In-house rubber and polymer technologists Developed first PTFE diaphragm in 1954 All Diaphragms are developed, compounded, and made in-house

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CRANE ELASTOMER AND POLYMER EXPERIENCE

We have over 75 years of experience in creating elastomers and polymers. We began rubber processing in 1932 and have in-house rubber and polymer technologist experts that develop compounding for these diaphragms. We were the first to develop a PTFE diaphragm in 1954, and in1956, Xomox began using PTFE for the sleeve plug valve.

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DIAPHRAGM VALVES

DIAPHRAGM MATERIALS

This chart can help in diaphragm material selection as it shows application environments and with what media they would be most applicable. For example, Nitrile works well with oils and fuels but no solids.

DIAPHRAGM MATERIAL SELECTION BEST

CORROSION & CHEMICAL RESISTANCE

Here you can see a chart that categorizes the best and worst diaphragm materials by abrasion resistance, and corrosion and chemical resistance, showing the tradeoffs of each. So, in terms of abrasion resistance, the best is the AA soft natural rubber, and the best for corrosion resistance is PTFE or TFM, however, this material also has the worst abrasion resistance. So to achieve better abrasion resistance, you would have to go down the corrosion scale to find something in the middle.

PTFE/TFM FKM HYPALON

NEOPRENE BUTYL/EP NITRILE Q NATURAL AA SOFT

ABRASION RESISTANCE

WORST

BEST

Natural Q

Water, effluent, abrasives

Natural AA

Abrasives, slurries, and dry powders

Butyl 300

Dilute acids and abrasives

EPM 425

Salts (acids water, etc.)

Nitrile C

Oils, fuels, no solids

Neoprene HT

Water, no oil

Hypalon 237

Strong acids, chlorine gas, sodium hypochlorite

Fluoroelastomer 226 Solvents, petrol unleaded, hydrocarbons Silicone 500

Pharma, milk, toothpaste

PTFE 214/xxx

Strong acids and virtually all chemicals

PTFE 214S/xxx

As 214 and steam

PTFE 214K/xxx

Chlorine and chlorinated brine (PVDF backing)

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LINING MATERIALS AVAILABLE LININGS

Glass Plastics Elastomers

These are the different linings that are available on a diaphragm valve. Glass, plastic, and elastomer, and you can see that the product shown here utilizes elastomer. We’ll now briefly go through each one in detail.

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LINING MATERIALS GLASS

More expensive than alternatives Must be careful during installation and maintenance to avoid breaking

Glass is more expensive than many alternatives and requires caution when installing and performing maintenance because of the risk of cracking. However, it is borosilicate glass, so it’s a very robust industrial class. We perform glass lining in the Satara site.

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DIAPHRAGM VALVES

LINING MATERIALS PLASTICS

Perfluoroalkoxy (PFA) Ethylene Tetrafluoroethylene (ETFE) Polyvinyldiene Fluoride (PVDF) Polypropylene (PP)

There are several different kinds of plastic liners. Perfluoroalkoxy is PFA which, as was mentioned earlier, is a type of melt-processable Teflon. It is a natural plastic with a very high chemical resistance and is ideal for high purity applications with a temperature range of -20 to +175 degrees Celsius. (-5 to +345 F) Ethylene tetrachloroethylene, or ETFE, is a tough polymer with good chemical and abrasion resistance. It is red and has low permeability. It is used in the chlor alkali industry because of its good acid and caustic resistance, and its temperature range is -20 to +150 degrees Celsius. (-5 to +300 F).

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Polyvinylidiene Fluoride (PVDF) is the third type of plastic lining. It is black and has a very low permeability. It applies to services such as sodium hypochlorite, bromine, and wet and dry chlorine. It is a nonstandard product offering, and its temperature range is -25 to 130 degrees Celsius (-5 to +266 F) Polypropylene (PP) is primarily used for water treatment, effluent lines, and chemical processing. This is the least expensive of the plastic liners, but it is highly corrosionresistant. It is off-white in color and has a temperature range of -20 to +85 degrees Celcisu. (-5 to +185 F).

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DIAPHRAGM VALVES

LINING MATERIALS

HRL • Hard Rubber Lined • Ebonite • WRc approval for potable water • Good resistance to acids, chlorine water, caustics • Poor abrasion resistance • 75 - 85 Shore D • -30 to +85 deg.C (-22 to +185 F)

ELASTOMERS

Hard Rubber Lined (HRL) • Ebonite Butyl Lined (BL) • IIR- Isobutylene Isoprene Soft Neoprene (NL) • Polychloroprene Soft Natural Rubber (AA) • Polyisoprene

BL • Butyl Lined • IIR- Isobutylene Isoprene • WRc approval for potable water • Good on combined corrosive and abrasive slurries, mineral acids • 66 - 66 IRHD •-40 to +110 deg.C (-40 to +230 F)

Elastomers are the final lining type and depending on the application, there are four kinds of elastomers: • Hard rubber lining which includes ebonite • Butyl-lined which includes IIRIsobutylene Isoprene

AA • Soft Natural Rubber • Polyisoprene • Designed for maximum abrasion resistance • Used for powders and slurries such as clays, cement, coal & gypsum • 40 - 46 IRHD • -30 to 85 deg.C (-22 to +185 F)

• Soft neoprene which includes Polychloroprene • And Soft natural rubber which includes Polyisoprene

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NL • Soft Neoprene • Polychloroprene • Resistance to hydrocarbons & good resistance to abrasives and corrosives • Used in waste and eﬄuent treatment applications 72 - 78 IRHD •-30 to +105 deg.C (-22 to +220 F)

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CAGE GUIDING DIAPHRAGM MATERIAL SELECTION BEST

CORROSION & CHEMICAL RESISTANCE

You can see the lining materials categorized on the chart we discussed earlier. The glass lining, for example, satisfies both abrasion and corrosion and chemical resistance Still, it may not offer the flexure needed in the customer’s application, in which case they’d have to select another based on their application requirements.

PFA

GLASS ETFE

NEOPRENE PP HRL

AA NATURAL

ABRASION RESISTANCE

WORST

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Natural AA lining

Abrasive media, dry solids

Ebonite HRL lining

Salt water, Dilute Acids, Demineralised water

Butyl lining

Dilute Acids, Low permeation. Lime

Neoprene lining

Oils, Sea water, Sludge

Glass lining

Abrasives, strong acids, high temperature, HCL

Polypropylene lining

Water, Alkali solutions

ETFE lining

Medium abrasives, Strong Acids

PFA lining

Strong acids, Chlorinated solutions, Aromatics

Halar

Low cost for Dilute acids, Water treatment

PVDF

Chlorine

PTFE 214S/xxx

As 214 and steam

PTFE 214K/xxx

Chlorine and chlorinated brine (PVDF backing) CRANE PROCESS FLOW TECHNOLOGIES

BUTYL

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BEST

DIAPHRAGM VALVES

ADVANTAGES DIAPHRAGM VALVE ADVANTAGES

Operating mechanism not in contact with line media Valve operates first time even after long idle periods 100% leak tight Lined for excellent corrosion resistance Suitable for control In-line maintenance No seat wear

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1. Because the operating mechanism does not come into contact with the line media, there is no contamination of the top works. So, if the valve is being used on slurry duty, the operating mechanism cannot seize. 2. Because of the relatively low torque of a diaphragm valve and the grease reservoir in the bonnet, the valve will open or close after long idle periods. 3. The diaphragm valve is 100% leaktight as standard, so there is no need to fit special glands to make it 100% leaktight. 4. Because of the vast range of linings available Saunders can offer a diaphragm valve to suit most applications. More importantly having a wide choice of body lining materials available allows us to keep prices low by offering alternative materials. 5. Because of the diaphragm valves linear flow characteristics the ‘A’ Type valve gives a good flow control range between 5% and 80% travel. 6. Maintenance on the diaphragm valve can be done in-line and the diaphragm can be easily replaced. 7. And finally, there is no seat wear because the seat is compressed.

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DIAPHRAGM VALVES

APPLICATIONS: ASEPTIC

Fine Chemicals Chromatography Cosmetics Filtration Demineralization Fermentation CIP Yeast Food & Beverage Pills & Soap We’ve reviewed some applications throughout the course, but we’ll provide comprehensive lists here. We are starting with Aseptic applications. Many applications listed here are inside pharmaceutical plants, like chromatography, filtration demineralization, and fermentation. They are all clean in-place processes within the pharmaceutical industry). Although the valve can be used in food and beverage service, our diaphragm valve is not designed as economically as what’s required for food service. So, food service requirements are typically a step below what a pharmaceutical market needs. That goes for pills and soap applications, as well.

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DIAPHRAGM VALVES

APPLICATIONS: CORROSIVE

Sulphuric Effluent Treatment Potable Water Fire Fighting Pulp & Paper Basic Chemicals HCL Fuels Acids & Alkalis Organics Toxic Fluids Here is the list of corrosive applications. We offer a Teflon-lined valve for literally any of these corrodents.

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DIAPHRAGM VALVES

APPLICATIONS: ABRASIVE

Gold Mining Cement Copper Mining Ceramics Sugar Coal Slurry Phosphoric Sand Fertilizers Titanium Sewage

Abrasive applications include those listed here. The valve’s full flow opening makes it great for abrasives, even the weir type, which can take up to 15% slurry. So wherever you see abrasives, the rubberlined diaphragm valve is a good option. 142

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DIAPHRAGM VALVES

APPLICATIONS: INDUSTRY

Marine Iron & Steel Vegetable Oil Paints Manufacture Tanning Oil Production Automobile Air and Gas Effluent Dye Liquors In terms of industrial applications, the diaphragm valve can be used in every industry, from process control to vegetable oil which is food processing.

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DIAPHRAGM VALVES

PROBLEMS AND CAUSES

SEAT LEAKAGE

Foreign material, damaged diaphragm, corrosion or abrasion of weir.

DIAPHRAGM DAMAGE OR LEAKAGE

Normal aging, defective material, damage during maintenance, improper assembly, incorrect material for service application.

BROKEN DIAPHRAGM ATTACHMENT TO COMPRESSOR

FLOW OBSTRUCTION

High cycling of valve, improper initial fit up

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The fluid system contains solids (slurries, rivers, lakes, seawater), tools or other debris left in the system, and parts from upstream components; low slurry velocity has allowed solids to settle out.

TECHNICAL TRAINING

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DIAPHRAGM VALVES

KNOWLEDGE CHECK

What are three available linings for Crane diaphragm valves?

Glass Plastics Elastomers

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5 Valve & Actuator Online Training Module

Pressure Control Valves

PRESSURE CONTROL VALVES

LEARNING OBJECTIVES At the completion of this lesson, you will be able to: 1. Given a picture of a pressure control valve, identify the major components. 2. Identify the following pressure control valve types: Safety Relief Vacuum Relief Pressure Reducing Fixed Orifice Regulation Differential Pressure Pressure Independent 3. Identify typical applications for pressure control valves. 4. Identify the Crane brands that manufacture pressure control valves.

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PRESSURE CONTROL VALVES

VALVE TYPES

LET’S TAKE A LOOK AT THE FOLLOWING TYPES OF PRESSURE CONTROL VALVES:

Safety Relief Vacuum Relief Pressure Reducing Fixed Orifice Regulation Differential Pressure Pressure Independent

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PRESSURE CONTROL VALVES

VALVE TYPES

Safety Relief

Protects system from Over pressure Combined pressure and temperature Safety valves incorporate Safety Relief Valves Pressure Relief Valves Relief Valves High discharge capacity option Adjustable pressure setting

First is the safety relief valve. This device is designed to protect the system from either overpressure or a combination of pressure and temperature. For example, safety relief valves are commonly found on residential hot water heaters. Suppose the heating element of the hot water heater shorts and causes continuous heating. In that case, the hot water will suddenly become steam, which, when under containment, will cause the pressure to increase, potentially leading to a negative outcome. The safety relief valve, however, protects the system and prevents pressure from building up in the system. Safety relief valves are referred to by several names, including pressure relief valves and, more plainly, relief valves, but they all have the same function. 150

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Safety relief valves offer high discharge capacity options which means that the outlet is larger than the inlet, allowing the discharge to occur at a lower pressure so the Delta P can be reduced. Additionally, these valves have an adjustable pressure setting so that the user can adjust the spring to the point where it will open; this opening point is known as cracking (or the cracking pressure). The more the pressure setting is adjusted down, the higher the spring force will be, causing the pressure to crack. The air pressure over the area of the disc is what produces the force which has overcome the force of the spring. Once it has done that, it opens up. The valve on the screen is one of Crane’s Nabic-branded valves.

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PRESSURE CONTROL VALVES

VALVE TYPES

Safety Relief

Enclosed chamber for hazardous services Easing lever to check operation for non-hazardous services

Continuing with the safety relief valve, an additional feature to highlight is the enclosed chamber for hazardous service, preventing those materials from leaking into the atmosphere. An easing lever allows the user to check the operation for nonhazardous services. In the example of the hot water heater, there is a lever on that valve, and the user can trip that lever, which would spill the previously contained hot water out of the valve and onto the floor. CRANE PROCESS FLOW TECHNOLOGIES

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151

PRESSURE CONTROL VALVES

VALVE COMPONENTS

Cap

Safety Relief Valve Adjusting Bolt

Bonnet

Spring

Spindle

Disc Insert

Set Screw

Nozzle Here you can see and become familiar with the various components of a safety relief valve. The adjusting bolt at the top can be loosened or tightened to compress or decompress the spring. The spring is a resultant force that operates against the disc that's under pressure. As the pressure 152

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increases, typically, there'll be a seal towards the inside diameter of that disc. So as soon as it opens, that pressure will have access to a greater area, and it will move up faster, and as soon as it cracks, it will be able to access even larger areas which are when the discharge will occur.

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PRESSURE CONTROL VALVES

VALVE COMPONENTS Safety Relief Valve

Some valves have outlet ports larger than inlet ports to give high discharge capacity

PressureAdjuster Manual Lever

Disc

Outlet

Seat

Inlet

Some valves have outlet ports larger than inlet ports which allow for a high discharge capacity. Here you can see a threaded outlet port and a flange inlet port, but again the outlet port is a larger diameter than the inlet.

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PRESSURE CONTROL VALVES

VALVE TYPES

Vacuum Relief

Spring-to-close device Used when increase invacuum must be limited Opens to restore vacuum to original pressure setting

The vacuum relief valve is the next type of pressure control valve we will discuss. This valve is a spring-to-close device used when an increase in vacuum must be limited. So, it opens to restore the vacuum to an original pressure setting. These valves are widely used in process plants, and Krombach and Nabic are the Crane brands that make them.

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PRESSURE CONTROL VALVES

VALVE TYPES

Anti-Vacuum

Used on steam systems Protects drying cylinders,tanks, etc. from collapse

Threaded

Here you can see an anti-vacuum steam system that protects drying cylinders and tanks from collapse.

Flanged

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PRESSURE CONTROL VALVES

VALVE TYPES

Anti-Vacuum

An Anti Vacuum Valve is a compact safety valve that minimizes the risk of an implosion of tanks when a vacuum condition arises. These conditions occur while filling or emptying the vessel of liquid, cool rinsing after hot-cleaning, or caustic cleaning in a CO2 atmosphere. When a vacuum in the tank or vessel is lower than the preset opening value, the valve opens and lets in atmospheric air.

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PRESSURE CONTROL VALVES

VALVE TYPES

Pressure Reducing

Reduces distribution pressures to usable pressures at outlet Maintains a constant outlet pressure regardless of fluctuating inlet pressures Automatic operation

The next valve type we will discuss is the Pressure Reducing Valve. This type of control valve reduces the distribution pressure to usable pressures at the outlet. It maintains a constant outlet pressure regardless of fluctuating inlet pressures, and its operation is automatic.

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PRESSURE CONTROL VALVES

VALVE COMPONENTS

Pressure Seal Pressure Reduction Chamber

Inlet Chamber Seat

Outlet Chamber Disc

When the pressure inside equipment such as boilers or pressure vessels increase beyond a specified value. The excess pressure may result in a catastrophic failure. Pressure relief devices are used to protect the equipment by relieving the excess pressure at preset levels. Expected relief pressure is important in determining which product is best suited to the application. The working principle of a conventional spring-loaded pressure relief valve is based on the balance of force. The spring load is preset to equal the force the inlet fluid exerts on the closed disk when the system pressure is at the valve's set pressure.

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During regular operation, when the valve is closed, the vessel pressure acts against the disk surface, which resists the spring force. When vessel pressure slightly exceeds the set pressure, fluid will move past the seating surface into the huddling chamber. The controlled pressure built in the chamber will overcome the spring force, causing the disk to lift and the valve to pop open. Once the valve has opened, an additional pressure buildup occurs. This additional force causes the disk to lift substantially at a pop. The valve closes when the inlet pressure has dropped sufficiently below the set pressure. The discharge capacity of this type of valve must be equal to or greater than the output of the boiler or system it protects.

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PRESSURE CONTROL VALVES

VALVE COMPONENTS

Stem moves disc between seat to maintain pressure

Pressure Adjuster

Distribution Pressure

Outlet Inlet

Reduced Pressure

Here you can see that the stem moved and reduced pressure is released.

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PRESSURE CONTROL VALVES

VALVE TYPES

Fixed Orifice Regulation (FODRV)

Allows commissioning engineer to measure & regulate flow rate: Differential pressure read across orifice Hand wheel position ignored for flow measurement Recordable set position Double regulating feature allows commissioned position to be set Accuracy ± 5% Used for isolation

The fixed orifice double regulation valve is the next type of pressure control valve. These can be found in heating, ventilation, and air circuits and are typically used for isolation and can be made available as either a butterfly or globe valve. The term ‘Orifice’ refers to the valve opening through which the water flows. With a fixed orifice double regulation valve the, ‘orifice’ that creates the measured pressure drop is an actual opening of a fixed size, hence the term ‘Fixed orifice’. Fixed Orifice 160

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Valves have a single value for the flow coefficient Kv. This valve type allows the commissioning engineer to measure and regulate the flow rate. It has a recordable set position and a double regulating feature that helps the commissioned position to be set. Hattersley is the Crane brand that produces this type of valve, which can often be found in hotels or hospitals to pump water to heat individual heating units in rooms.

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PRESSURE CONTROL VALVES

VALVE TYPES

Fixed Orifice Regulation (FODRV) Test Points

FLOW

Orifice Insert

This is what it looks like when the valve is commissioned. You can see where the diameter machining intersects with the test port’s drill hole. The orifice causes a pressure drop, and the test points allow for measuring it. The pressure drop is converted to flow so the commissioning engineer can set it to the design

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flow usually installed in the return pipework. You see a Y-angle globe valve with a fixed orifice that allows for the commissioning to take place on the spot. And with one valve, the instrument can be attached, adjusted, and set to the desired flow.

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PRESSURE CONTROL VALVES

VALVE TYPES

Fixed Orifice Regulation (FODRV) Installation of these vale types is manually done using instrumentation.

Typical Installed Position

Return Pipework to Terminal Unit

Branch Return Pipework Here you can see the installation of another type of fixed orifice regulation valve, but with a different kind of connection, the Pegler type of clamp fitting. The engineer here is inserting the copper tubing into the spitting and then crimping it over it. This line he is installing will feed into the next floor up in the building.

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PRESSURE CONTROL VALVES

VALVE TYPES

Differential Pressure (DPCV)

Controls differential pressure within installed circuit Simplifies the commissioning process Control range can be set and is adjustable Protects control valve authority

The differential pressure control valve is the next type of pressure control valve. As its name implies, this valve controls the differential pressure within an installed circuit. Regardless of the pressure in the valve, it controls how much Delta P is across that valve, and therefore the flow so that it stays the same. It is developed to handle the problems caused by system control valves and variable speed pumps. The self-acting differential pressure control valve is designed to absorb unwanted head pressure and limit the differential pressure across the circuit. Crane’s Hattersley produces this type of valve.

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VALVE TYPES

Differential Pressure (DPCV) Diaphragm Differential Pressure Adjuster

Lower Chamber

Upper Chamber

FLOW

Here you can see the makeup of a differential pressure Y globe valve. Unlike a regulating valve where the force balance occurs from the input to the spring, in a differential pressure valve, the force balance occurs around Delta P. DPCV utilizes a diaphragm that segregates the top and lower chambers of the valve. The Delta P on the downstream side, or the low-pressure side, is being ported above into the upper chamber. That Delta P is set by the pressure adjuster, which could be a mechanical setting, or there could be an electric actuator here, and the flow can be changed based on computer algorithms and the control system.

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PRESSURE CONTROL VALVES

VALVE TYPES

Differential Pressure (DPCV)

Typical Installed Position

Typically, this is the install position you see with a differential pressure valve in the supply line. The valve maintains the flow that is going into this system of rooms and the flow rate that’s required by these rooms is also maintained. The units you see on each are the various fan coil units or heat exchangers for each room.

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PRESSURE CONTROL VALVES

VALVE TYPES

Pressure Independent

Flow regulation with a setting dial Recordable set position Differential pressure control Two port control valve when actuator fitted Constant flow regulator when actuator not fitted Threaded or flanged

The pressure-independent control valve is the final type we will discuss in this course. This multifunctional valve that combines the operations of 3 different valve types into one: a differential pressure control valve, a regulating valve, and a two-port control valve. The Crane brand that makes it is Crane Fluid Systems, Hattersley. It features a flow regulation, a setting dial and a recordable set position. It can be threaded or flanged.

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PRESSURE CONTROL VALVES

VALVE TYPES

Pressure Independent Test Points

FLOW

Stem Differential Pressure Control

Actuator Fixing

In this valve type, you can adjust the valve's flow rate since it is a control valve. And as you can see, a differential pressure control unit and test points are present, and all three can be combined into one valve. So, regardless of pressure, differential pressure control can be maintained. It is internally ported so that the outlet pressure is ported to the upstream pressure. Then, it can be adjusted with an actuator, and all of this can be done in one valve.

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This type of product is needed in a control loop, as it can be adjusted and can adapt to the variable demands readily and automatically. Once the system is set up, the right flow is maintained because the differential pressure valve, can be controlled. For example, if a room needs to be warmed, you will increase the temperature on the thermostat, and as a result, the control valve would adjust to open up the flow of the hot water into the regulator.

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PRESSURE CONTROL VALVES

VALVE TYPES

Pressure Independent

Return pipework to terminal unit

Typical Installed Position

As stated, one of these valve types would be placed on each control unit. There could also be a larger one that would be installed on the main supply line for each of the branch circuits. These last two valves are critically important. For example: When there is a variable frequency drive preheating an HVAC system in a LEED certified or energy-efficient building, will have frequency pumps operating the chilled water and hot water systems because they’re more efficient in operation.

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As stated, within Crane, the brands that manufacture these regulators and pressure control valves for HVAC systems are our building service utility group Crane Fluid Systems, and Hattersley. In addition, the pressure relief valve rathe manufactured by Nabic and the vacuum relief valve is produced by Krombach.

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PRESSURE CONTROL VALVES

APPLICATIONS Pressure control valves are used:

In process control plants Mainly for steam and water applications In situations were pressure needs to be regulated To protect tanks, cylinders, etc. from collapse

Pressure control values are used in process control plants and mainly for steam or water applications. They work well in situations where ere pressure needs to be regulated, like in protecting tanks, cylinders, etc., from collapse. These pressure control systems are used in lots of different applications.

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PRESSURE CONTROL VALVES

CRANE BRANDS

As a review, you can see the different Crane brands and valve types they produce here. Krombach manufactures the vacuum relief valve, and Crane Fluid Systems manufactures both the differential pressure control valve and pressure independent control valve. And Nabic produces the pressure relief valve.

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TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

PRESSURE CONTROL VALVES

SUMMARY Let’s take a look at what we have discussed so far: 1. The major components of a pressure control valve. 2. We looked at examples of the following pressure control valves: Safety Relief Vacuum Relief Pressure Reducing Fixed Orifice Regulation Differential Pressure Pressure Independent 3. We reviewed some applications for pressure control valves. 4. We explored Crane brands that manufacture pressure control valves.

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6 Valve & Actuator Online Training Module

Check Valves

CHECK VALVES

LEARNING OBJECTIVES At the completion of this lesson, you will be able to: 1. Describe the purpose of a check valve. 2. Given a picture of a check valve, identify the major components. 3. Identify the following check valve types: Swing Tilting Disc Lift Stop 5. Identify typical applications Dual Plate for check valves. Nozzle 6. identify at least one likely cause for each given Flex problem associated with Floating Ball a check valve. 4. List advantages and 7. Given a list of check valves, disadvantages of identify the Crane brand or check valves. brands that manufacture each of them. 174

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CHECK VALVES

CHECK VALVE FUNCTIONS WHAT IS THE PURPOSE OF A CHECK VALVE?

Check valves prevent fluid flow reversal. Two typical reverse flow prevention applications exist: At the outlet of a pump or compressor At points where different portions of a piping system join a common header Check Valves: protect equipment prevent contamination protect low pressure systems from high pressure surges

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CHECK VALVES

VALVE TYPES

176

Swing Tilting Disc Lift Stop Dual Plate Nozzle Flex Floating Ball

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CHECK VALVES

SWING CHECK VALVE Cover Studs

Bonnet

Cover Nuts

Bonnet Gasket

Hinge Pin Hinge Arm

Body

Disc Disc Stud Nut

Seat Ring

We’ll first start with the swing check valve. Swing checks represent the “C” in GGC. You may remember that GGC is short for Gate, Globe, and Check valves, but specifically for Swing Check valves.

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You’ll notice on this diagram that the swing check valve has many of the same components as other valve types, like the body, bonnet, and gasket. Specifically, in this design though, there is a hinge pin, hinge arm, and disc, and seat, making it very similar to a globe valve, but the difference is that this disc swings up out of the way? So as flow comes through, it pushes the disc up, and the flow can pass through the line.

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CHECK VALVES

KNOWLEDGE CHECK

KNOWLEDGE C HEC K

Can you identify the parts of a swing check valve?

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CHECK VALVES

SWING CHECK In this graphic, as fluid passes through the valve, the disc will seat up to the stop as far as it can go to allow for more fluid flow.

1. Casting and machining tolerances designed for HF service 2. Disc stop for open position provides more Cv’s than most swing check designs. CRANE PROCESS FLOW TECHNOLOGIES

3. Anti-Rotation lugs allows disc to seat concentrically and prevent rotation 4. Full ported, high Cv seat ring design seal welded to body TECHNICAL TRAINING

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CHECK VALVES

SWING CHECK Wafer Style

Wafer Pattern PFA Lined Only Sizes 3” thru 12”

So we’ve just reviewed a standard swing check valve included in the GGC classification, or gate, globe, and check. Here you can see a different type of swing check valve with is the wafer style. This is a Xomox PFA-Lined check valve. In this valve type, the flange holds the pin piece, which is an integral part of the disc, in place and then pivot into the pipeline itself.

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SWING CHECK Bronze

Low velocity services, especially liquids and infrequent change of direction in backflow prevention Generally used with gate valves because of similar flow characteristics

This is a bronze swing check valve. This valve type is typically used in low-velocity services characterized by infrequent changes of direction. They are generally used with gate valves because of their similar flow characteristics. This valve is primarily for water applications like HVAC and hot/cold water.

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CHECK VALVES

SWING CHECK Y Pattern

Good flow characteristics Can be installed in both horizontal and vertical lines with upward flow The 45o seat aids in back seating under low pressures Screwed cap design allows for quick and easy removal

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SWING CHECK Tilting Disc

Now that we’ve gone through the various swing check valves, we’ll move on to the next type of check valve, the tilting disc. The Tilting disc looks a lot like a swing check valve but is not the same. In a tilting disc valve, the disc itself has a pivot on the disc, and as it swings up out of the way, it’s still in the path of the fluid. So, when the flow reverses, it’s very fast-acting in stopping that flow. Therefore the effect of the water hammer is better here than in a swing check valve because it doesn’t take as long to travel. The

disadvantage, though is the pressure drop or flow rate. There is a higher pressure drop and lower flow rate, so it doesn’t have as much flow capacity.

2 piece valve Cannot be maintained while in the line, must be taken out Does not have a big arm hanging down so it does not slam as much

The tilting disk check valve is selfactuated, one-way or non-return valve similar to the swing check valve. Like the swing check, the tilting disk type keeps fluid resistance and turbulence low because of its straight-through design. The straight through design of the tilting disk offers many advantages compared to other designs.

• Reverse ﬂow prevention • Non-Slam design • Single direction only • Can require sizing and speciﬁc placement • Easy to repair • Heavy duty design/ structure • Good for high temperature/ high pressure service

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CHECK VALVES

SWING CHECK Tilting Disc Pressure Seal Internal Disc Hanger

Bonnet Stop

Seat Ring

Disc

Body

Here you can see the inside of the valve better. The tilting disc uses the pressure seal bonnet, and the internal disc hanger is a fixed arm that puts the pivot point in the flow path.

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SWING CHECK Lift

The lift check valve is the next type of valve we will discuss. You’ll notice that it looks like the body of a globe valve because inside, it is the body of a globe valve. However, the addition of a lift disc and special cover makes it a check value. The flow direction in this type of valve is in from the side, up, and then out.

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CHECK VALVES

STOP CHECK Yoke Sleeves

Handwheel

Eye Bolts

Stem

Bonnet Joint

Backseat

Seat Ring

Disc

Body

A stop check is a combination of globe valve and check valve combined. The disc has a sliding capability on the stem in this valve type. So, if it’s in the open position and there is no flow or flow reversal, the disc seats into the body, and as flow come through, it can push the disc up and then flows out. Then as the disc closes, the flow can be adjusted, or if it’s closed all the way, it stops the flow. The sliding mechanism of the disc on the stem is what gives this valve the functionality of a lift check, but it is also an isolation glove valve in one, making it a stop valve. 186

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STOP CHECK HOW IS THE STOP CHECK VALVE DIFFERENT FROM A GLOBE VALVE? The valve stem is not connected to the disc In the open position the disc is free to respond to the flow

This diagram of a Pacific Stop Valve illustrates that functionality. The disc can move on the shaft in such a way that the pressure coming in can lift it up. But if the flow reverses, the disc stops it, or if the disc is closed all the way, it also stops the flow. CRANE PROCESS FLOW TECHNOLOGIES

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CHECK VALVES

STOP CHECK Y Pattern

The previous diagram illustrated a T-pattern stop check valve, but Y-pattern stop check valves are also available, which are designed according to the same concept except that the mechanism is used in a Y configuration of the body.

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CHECK VALVES

DUAL PLATE

The dual plate check valve is next. This shows a lug-type body that is for studs and nuts or bolts and nuts. And this is a wafer that gets sandwiched between two pipeline flanges.

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CHECK VALVES

DUAL PLATE LIGHTWEIGHT PLATE DESIGN

INDEPENDENT SPRINGS

LONG-LEG SPRING ACTION

HINGE SUPPORT SLEEVE

Increased seating & operation efficiency

No seat scrubbing

Plates close independently

Reduces friction Independent plate suspension Some of the mechanical components are illustrated here, including lightweight plates for efficient opening and closing, independent springs, hinge support that reduces friction, and long-leg spring action so there’s no seat scrubbing.

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DUAL PLATE Opening

The flow takes the two plates and pushes them tightly against one another, back to back, so that they are in a full open position.

These advantages have been built into the valve so that when the pressure occurs, it compresses the springs and lets the flow through.

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CHECK VALVES

DUAL PLATE Closing

As the rate decreases, the springs take over and start moving back, and then the flow completes it into a hard stop. The benefit to a spring-assisted piece is that the valve doesn’t have to rely on gravity. These springs can also be made stronger or weaker based on the flow velocity and type of media to optimize the reduction or elimination of the effects of the water hammer. That is the engineered aspect of this valve. It can be tuned to meet the customer’s demand and optimize performance.

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NOZZLE Body + Integral Cone

(Single piece casting design)

Compac-Noz Seat

Guidance Housing Disc

We referenced a Noz-Chek valve earlier, but here you can see a Compac-Noz valve. Engineers today know the valve characteristics they need for their particular system installations. They require valves to close quickly and prevent flow reversal that can damage mechanical equipment and cause destructive events such as water hammer. Space and weight restrictions are very often a significant concern. Compac-Noz® offers an economic alternative to a full-body design.

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It features a short face-to-face, light weight, quick closing non-slam nozzle check valve functionality. Compac-Noz valves deliver an effective dynamic response under various flow deceleration conditions. The dynamic performance characteristics of the Compac-Noz valves are compared to swing check and dual plate spring-assisted check valves in Figure 1.

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CHECK VALVES

FLEX

Now let’s move on to the Flex Check Valve, which is produced by our Viking Johnson brand.

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FLEX

WHY USE A FLEX CHECK? Quiet operation Only one moving part No pivot pins No bearings No mechanical hinges No linkage mechanisms No packing

Flex check valves are a swing check valves with a flapper made of rubber that easily moves out of the way as fluid flows. It is a simple configuration that operates quietly and features only one moving part. Flex check valves have no pivot pins, no bearings, no mechanical hinges or linkage mechanisms, and no packing. It is a very straightforward valve. CRANE PROCESS FLOW TECHNOLOGIES

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CHECK VALVES

FLOATING BALL

The floating ball check valve is next and is produced by Krombach and Xomox. In this valve, the ball acts as the check mechanism. So as the fluid flows through the valve, it pushes the ball off the seat and there are typically 3 legs that support the ball and allow the fluid to flow around the ball and downstream. The flow reversal then pushes the ball back into the seat. In most cases, a ball check must be in a horizontal line with the flow going up. And then the back falls back down to close it.

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FLOATING BALL

Antique Snorkel

This is very similar to a floating ball on a snorkel. As the water comes up, it pushes the ball against the seat, and it opens it up as the water comes down. And this is the final type of check valve we will discuss.

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CHECK VALVES

ADVANTAGES/ DISADVANTAGES

Advantages

Disadvantages

Prevents backflow Maintains pressure Most can be installed horizontally or vertically

So what are the advantages and disadvantages of check valves? Well, in general, check valves prevent backflow, and maintain pressure, and most can be installed horizontally or vertically (with the exception of the floating ball check valve, of course).

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Can’t be used with pulsating systems Closing element may slam close causing damage and excessive wear

Regarding disadvantages, they cannot be used with pulsating service systems ( except for of the Noz-Chek valve that can be used in reciprocating services). Another disadvantage is that the closing element may slam close causing, damage and excessive wear, significantly if it’s not sized correctly.

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TYPICAL APPLICATIONS

There are several applications that are suitable for check valve usage. Metal designs can be used in all temperatures and pressures. Lined valves can be used in low to medium temperatures and pressures, and in harsh or corrosive gases liquids and slurries. Swing, tilting disc, dual-plate, and nozzle check valves can be used when there is a high Cv need. In addition, stop check valves can be used in boiler operations or other places that require a shut-off valve. Dual-plate and nozzle check valves can be used when there is a concern of waterhammer in a system. Again, the springs of a Duo-Chek can be tuned to lower the water hammer effect, but if that isn’t good enough, the Noz-Chek will work. And Flex check valves can be used for sludge and sewage applications.

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CHECK VALVES CAN BE USED FOR: All temperatures and pressures (metal designs) Low to medium temperatures and pressures (lined valves) Harsh or corrosive gasses, liquids, or slurries (lined valves) High Cv needs (swing, tilting disc, dual-plate, or nozzle) Boiler operations or other places for shut-off (stop) Water-hammer concerns (dual-plate, nozzle) Sludge or sewage (flex) TECHNICAL TRAINING

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TYPICAL APPLICATIONS CHECK VALVES CAN BE SEEN IN INDUSTRIES SUCH AS: Refining Petrochemical and Chemical Oilfield production Water Steam Refining petro Waste-water management systems ManufacturingSludge or sewage (flex)

Check valves can be seen in these industries listed here, including refining, petrochemical, water, steam, and manufacturing. But really, they can be used anywhere protection from backflow is needed.

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CHECK VALVES

PROBLEMS & CAUSES Valve doesn’t shut Physical blockage, corrosion, excessive wear, disc stuck in bonnet, missing disc, broken spring

Valve doesn’t open Physical blockage, corrosion seat leakage, foreign material, seat/disc damaged, seat/disc repaired wrong, excessive hinge pin/bearing wear

Flange leakage Wrong bolt torqueing, scratched sealing surface, wrong seal used, seal not properly installed This is a lit of various problems that could occur with a check valve and the potential causes. So if the valve doesn’t shut, there’s likely some physical blockage, but other reasons could be corrosion, excessive wear, a broken spring, etc. If the valve doesn’t open, again, that could be caused by physical blockage, but also,

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the seat or disc could be damaged, or it could be the result of excessive hinge pin or bearing wear. If the flange is leaking, that could be the result of the wrong bolt torqueing, could have used a scratched sealing surface or the wrong seal.

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CHECK VALVES

PROBLEMS & CAUSES Worn or broken springs Valve not fully open due to overdesign or reduced flow, corrosion, embrittlement

Flow obstruction Fluid system contains solids (rivers, lakes, seawater), tools or other debris left in system, parts from upstream components

Water-hammer Rapid interruption of flow (check valve slam) results in pressure wave, misapplication

Worn or broken swings can result if the valve isn’t sized correctly, resulting in spring failure (particularly in a Duo-Chek valve). Flow obstruction can often occur because of where the valve is being used, like in streams or rivers, as there could be debris in the fluid.

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Water hammer occurs when there is rapid interruption of flow, resulting in a pressure wave. Excessive hinge pin, stem, bearing, or sleeve wear can occur if the valve is not fully open due to overdesign or reduced flow.

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PROBLEMS & CAUSES Excessive hinge pin, stem, bearing or sleeve wear Valve not fully open due to overdesign or reduced flow, backstop not long enough, upstream flow disturbances

Disc nut broken/missing Valve not fully open due to overdesign or reduced flow, disc rotating, nut not pinned to disc stud

Flow obstruction Fluid system contains solids (rivers, lakes, seawater), tools or other debris left in system, parts from upstream components If the disc nut is broken or missing, the value is often not fully open, again due to overdesign or reduced flow. It could also be caused by disc rotation or the nut not being pinned to the disc stud at manufacture, which is highly unlikely in a Crane valve.

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7 Valve & Actuator Online Training Module

Butterfly Valves

BUTTERFLY VALVES

LEARNING OBJECTIVES At the completion of this lesson, you will be able to: 1. Given a picture of a butterfly 5. Given a list of butterfly valve types, identify at least one valve, identify the major typical application for components. each of them. 2. Identify the following 6. Identify at least one likely butterfly valve types: cause for each given Concentric problem associated Double Offset with a butterfly valve. Triple Offset 7. Given a list of butterfly 3. List three butterfly valve valves, identify the body designs. Crane brand or brands 4. List advantages and that manufacture disadvantages of each of them. butterfly valves.

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MEET THE VALVE

A circular disc that rotates 90 degrees to open or shut Disc and shaft are always in the flow stream Used for on/off applications as well as throttling Very Compact Wide range of applications

So, let’s meet the valve. The butterfly valve features a circular disc that rotates 90 degrees to open or shut. Therefore, the disc and shaft are always in the flow stream. Unlike a gate valve, butterfly valves have less flow capacity because the fluid flow will be impinged by the disc and shaft that are always in the waterway. Butterfly valves are used for on/off applications and throttling. It is a very narrow valve and therefore very compact, so it can be used in many applications.

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BUTTERFLY VALVES

VALVE COMPONENTS

Stem

Gland Flange Packing Gland

Packing

Bearing

Valve Body Soft-Seat

Disc

Seal Retainer Here you can see a diagram of a butterfly valve and its key components. One thing to point out is that here you can see one set of bearings, but there would be another set at the bottom, as well, to keep the shaft centered. Also, there is a retainer and seat in this particular case. The seal retainer keeps the seat in place until the flanges are added. 208

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KNOWLEDGE CHECK

KNOWLEDGE C HEC K

Can you identify the parts of a swing check valve?

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BUTTERFLY VALVES

VALVE TYPES

Concentric

Double Offset

Triple Offset 1

3 2

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VALVE TYPES

Concentric

A metal disc is centered in the waterway with the shaft on the centerline of the disc The disc is either iron, stainless steel or aluminum bronze The design is economical and seals bubble tight Most common offering as Resilient Seated but available Teflon lined CRANE PROCESS FLOW TECHNOLOGIES

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In a concentric valve, the disc is centered in the waterway with the shaft on the center line of the disc. The disc could be iron, stainless steel, aluminum bronze or even coated. A concentric butterfly valve design is economical and bubble tight. It is most commonly offered as Resilient Seated, but it’s also available Teflon lined. So the term Resilient-Seated Butterfly Valve most likely refers to a concentric design. |

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BUTTERFLY VALVES

VALVE TYPES

Concentric

Single-piece stem design with pinned shaft to disc connection Two-piece shaft with drive shaft and pilot shaft offers capability for special alloy or coated discs

There are two different types of concentric valves available. The first is a single-piece stem design where there is a shaft going all the way through the disc. Some pins go through the disc into the shaft that transmit the shaft's torque to the disc. The Crane valve that falls into this category is the Center Line 200. The second type is a two-piece design with a pilot in the top with a drive shaft, and the bottom is pivot pin. The Crane valve that falls into this category is the Center Line RS. 212

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The advantage of the two-piece design is that you can coat the disc without interruption, whereas with the one-piece shaft, there are pins going through it. So if the disc is coated and then a pin is driven through it, the coating on the disc is rendered useless. The two-piece valve type is more conducive for corrosive applications like low-end chemical process plants and oil and gas applications with more corrosive atmospheres and environments. At the same time, the single-piece valve is used more in utility services like water systems and fairly generic applications.

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BUTTERFLY VALVES

VALVE TYPES

Double Offset

Low weight Low torque Competitive initial cost Tight shut-off Long life Less maintenance Easy to install Easy actuation

Double - Centerline also offset from pipe centerline The double offset valve is lower in weight, has low torque, is competitively priced, features a tight shut-off, and is characterized by long life, less maintenance, and easy actuation. Unlike the concentric valve, the double offset valve is not on the center line but has two offsets: the seat and the shaft. So, the shaft is offset from the center of the body, and the disc seat is offset from CRANE PROCESS FLOW TECHNOLOGIES

the center line. That means that as the valve turns, it came off the seat, whereas in a concentric valve, the top and bottom are always in contact. Therefore, the seat on a double offset valve doesn’t wear out as fast and has a significantly longer life than the concentric. Because of this “higher performance”, was dubbed a high-performance butterfly valve, which now most often refers to a double offset butterfly valve.

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BUTTERFLY VALVES

VALVE TYPES

Double Offset

Krombach AK125 Double Eccentric 100 percent fabricated. This is a fabricated double offset valve. Krombach manufactures substantial diameter fabricated double offset butterfly valves, both bare steel and fully rubber-lined. You can see that these valves are quite large, as the person standing there is 6 feet tall.

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Double offset valves of this size tend to be used on water inlets for power plants. When fully lined, they can use them in corrosive seawater applications. Though these valves may operate at a higher performance than other valves, they are not considered High-Performance Butterfly Valves because that term is reserved for the style we discussed that is more in line with a wafer style valve, not fabricated valves such as this.

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BUTTERFLY VALVES

VALVE TYPES

Triple Offset

Developed by Adams Valves in 1960. Began marketing in the USA in the 1980’s. Successful in fire safe design, tighter shut-off, and ¼ turn design.

The triple offset is the third type of valve. Adams developed it in 1960 and marketed in the United States in the 1980s. These valves are inherently fire safe, unlike the resilient seated butterfly valve that is rubber lined or the double offset with a resilient seat. However, most manufacturers do offer a fire-safe backup design. With the triple offset valve, that’s not needed as it is inherently fire safe. This valve type has a metal-to-metal seat and features a tight shutoff, quarter-turn design, so it’s easy to automate. Triple offset valves, or TOVs as their known, have been widely used in high-temperature applications, including steam, due to the metal-to-metal tight shutoff. They also do not cause any sticking or galling and have more minor seat wear and longer service life. TOVs are very similar to gate valves, becoming known as rotary gate valves. This is because the triple offset butterfly valve is torque seated which is comparable to the gate valve, which is rotary thrust seated. CRANE PROCESS FLOW TECHNOLOGIES

TOVs gained widespread use in high temperature applications, including steam, due to metal to metal tight shut off. Self releasing taper design No sticking, galling, or rubbing Less seat wear and longer service life

So the more it is pushed into the seat, the tighter it gets, the same as a wedge plug valve where the more the gate is pushed, the tighter it seals. According to Machinery’s Handbook, a sealing angle above 16 degrees is referred to as a “self-releasing” taper design. Therefore the Flowseal MS and Xomox TOV, which incorporates a 25-degree seat angle, would be considered a “self-releasing” design, resulting in no sticking, galling, or rubbing. This allows for much more minor seat wear and longer service life.

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BUTTERFLY VALVES

VALVE TYPES

Triple Offset

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Saunders, div. of Alfa Laval, was purchased by Crane in 2001. The Saunders TOV eventually became the Flowseal MS (also marketed as the Xomox 9000 TOV) Krombach was acquired by Crane in 2008 and included the Tri-EX AK110 product offering through 112” diameter Crane FKX9000 single piece cast body design is Crane’s newest offering insizes 3” up to 48“ (DN 80 up to DN 1200); pressure classes 150, 300 & 600 (PN 10, 16, 25, 40); and in Lug and Double Flanged Short & Long Patterns CRANE PROCESS FLOW TECHNOLOGIES

Crane’s history with triple offset valves started in 2001 through the acquisition of Saunders Alfa Laval. That TOV eventually became the Flowseal MS. In 2008, the acquisition of Krombach brought the TriEx AK110. Several years ago, Crane’s product development team designed a new product that combined the best features of those three valves and increased the packing so that it would be suitable for the chemical processing industry, resulting in the Crane FKX 9000. This triple offset valve features a single cast piece design throughout the entire range and has become the standard Crane offering for triple offset butterfly valves.

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BUTTERFLY VALVES

VALVE TYPES

Triple Offset

Seat Angle 25º

center line, which makes up the third offset. So, the angle is actually offset. So as it closes, the angle is forced further in, and the seat is moved tighter. So, it’s a torque seated valve and if the torque is lost, so is the sealing capability. Whereas the single offset and double offset valves are position seated, they seal as long as they get to the closes position.

Here you can see the functionality of the triple offset valve. As the name implies, there are three offsets. Like the double offset valve, there is an offset of the shaft from the center line of the body and an offset of the seat from the center line of the shaft. However, the difference is the angle. The angle of the double offset comes to the center line. But here, the seat angle meets off-center to the CRANE PROCESS FLOW TECHNOLOGIES

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BUTTERFLY VALVES

VALVE TYPES

Graphite

Triple Offset FLEXIBLE SEAL RING: 3 tightening laminations of stainless steel 2 laminations of graphite Triple safety against leakage Graphite laminations give elasticity Graphite provides lubrication andreduces wear and friction

Stainless Steel In this valve, there are typically three tightening laminations made of stainless steel and two made of graphite. There could be a combination of more or less than that, but the standard is this configuration with three metal seats making contact with the seat. The graphite laminations are what give it some elasticity, as well as lubrication in reducing friction and wear.

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BUTTERFLY VALVES

VALVE BODY TYPES Wafer In a wafer configuration, the wafer sandwiches between two flanges that are held together by a bolt.

Lug

Double Flange

Valve

In a lug configuration, holes are drilled and tapped into the body, and the flanges are held in place by bolts typically stud and nut. With a lug body, one flange can be taken off, and the valve can become the dead-end of the pipe, making it suitable for “dead-end service.” However, for that to apply, the valve’s retainer must be designed to accept the full rated pressure of the valve in the pipeline. But if it’s not, then the flange of that valve cannot be removed for it to be used as the dead end. This particular valve shows a snap-in retainer which snaps in, and the flange holds it in place, so it would not be used as a dead end. CRANE PROCESS FLOW TECHNOLOGIES

The last body configuration is the double flange. It is made up of two flanges. In a double flange valve, many of the holes are through holes, and some are drilled and tapped. Typically the two holes at the top and the two at the bottom are the ones that are drilled and tapped because holes can’t be drilled through the shaft, bearings, and packing glands which run top to bottom and still have room in the back for the washer and the nut.

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BUTTERFLY VALVES

ADVANTAGES/ DISADVANTAGES Advantages

There are several advantages to utilizing butterfly valves versus others. Butterfly valves are typically 3 inches or larger because most of the valve is consumed by the shaft and the disc, not leaving much for the opening if the valve is smaller than 3 inches. Since the triple offset valve is thinner with a wafer style design, they are lighter in weight and more economical than a metal seated ball valve, for instance. However, it’s probably more expensive than a gate valve. 220

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Typically 3” and larger (2” sizes available) Lighter weight and lower cost Easy installation Simple quarter turn actuation Simple lever operation up to 8”

These valves are easy to install and feature a simple quarter-turn actuation. As opposed to a gate valve, these valves are automated, and in an application like an oil refinery, that is a benefit that makes the operator’s job much mire manageable. Concentric and double offset butterfly valves have a simple lever operation up to 8”. However, a lever can’t be used on a triple offset valve because it is torque seated. It can only be used on a position-seated valve. Torque seated valves have gear operators.

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BUTTERFLY VALVES

ADVANTAGES/ DISADVANTAGES Advantages

Low torque Bubble tight sealing with soft seats Fire-tested models available High temperature metal seats available

Butterfly valves, in general have low torque. They have bubble-tight sealing. They are available in fire-test models, especially the triple offset valve, which is inherently fire safe. And high-temperature metal seats are available. CRANE PROCESS FLOW TECHNOLOGIES

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BUTTERFLY VALVES

ADVANTAGES/ DISADVANTAGES Disadvantages

Not piggable Disc disrupts flow

In terms of disadvantages, butterfly valves are not piggable, and since the disc and the shaft are always in the flow, they will have less flow capacity than other fulltorque opening valves, like gate and ball valves.

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BUTTERFLY VALVES

APPLICATIONS

Concentric

Low temperature and pressure Building utilities, HVAC (One-piece shaft) Chemical, Flue gas desulphurization (Two-piece shaft) Lined pipe applications

As for applications, the concentric valve is typically used in low temperature, low-pressure pressure environments. You ou would see the one-piece shaft design in building utilities and HVAC applications. In contrast, the twopiece shaft design would be found in chemical and flue gas desulfurization applications, mainly because of the flexibility to use different discs, like alloy, Rosannecoated discs, and other special coatings that work well in these environments. These valves can also be used in lined pipe applications. Xomox has concentric a offering which is fully Teflon lined, which makes it suitable for very corrosive applications. CRANE PROCESS FLOW TECHNOLOGIES

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BUTTERFLY VALVES

APPLICATIONS

Double Offset

Medium temperature and pressure Chemical, pulp and paper, oil refinery Cryogenic applications Power generation (metal seated)

The double offset valve is suitable for medium temperature and pressure applications, and some cryogenic applications. It works well in chemical, pulp, paper and oil refinery environments, and if metalseated, it can be suitable for power generation applications. 224

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BUTTERFLY VALVES

APPLICATIONS

Triple Offset

High temperature and pressure Applications needing Class 6 with metal seat Power/steam generation Cryogenic applications

And then triple offset. Higher temperatures and pressures. Application needing class six with middle seat. Power and steam applications, cryogenic applications. This is an excellent valve for cryogenic applications because it’s all metal. Metal to metal seat, graphite packing, and graphite in the seating itself. So, you don’t have the vast differences and thermal expansion that you would have with any soft seat, so it’s a great valve for cryogenic applications. CRANE PROCESS FLOW TECHNOLOGIES

The triple offset valve is suitable for higher temperatures and pressures, as well as any application that meets class 6 with a metal seat or requires zero leakage. It can be found in power and steam applications. Also, because of its metalto-metal seat, graphite packing, and graphite in the seating itself, this valve is well suited for cryogenic applications.

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BUTTERFLY VALVES

PROBLEMS & CAUSES Valve does not open/shut on demand Physical blockage, corrosion, broken actuator, broken stem, missing or broken key

Valve partially strokes but does not reach desired position Excessive stem load due to packing or seat friction, actuator problems

Packing leakage Normal packing wear, incorrect packing set, inadequate packing consolidation, worn stem

We’ll now review some problems associated with butterfly valves and their causes. 1. If the valve does not open or shut on demand, there could be a physical blockage or corrosion in the valve. The actuator or stem could also be broken, or if the key that drives the mechanism could be sheared. 2. If the valve partially strokes but does not reach the desired position, it could be caused by an excessive stem load, particularly on a double or triple offset valve.

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So, if excessive torque is added to the packing gland, the valve can lock up. 3. Packing leakage can be caused by inadequate packing consolidation. When the packing sets are added, they can’t be compressed simultaneously. The packing has to be loaded from the bottom up, according to the manufacturer’s specifications, and compressed after each packing set has been added, one by one.

TECHNICAL TRAINING

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BUTTERFLY VALVES

PROBLEMS & CAUSES Seat leakage Foreign material, seat or disc damaged, seat or disc installed wrong, insufficient stem torque

Valve to pipe joint leakage Wrong bolt torqueing, scratched sealing surface, wrong seal used, seal not properly installed

Valve cavitation or vibration Operating too near the valve seats

4. Seat leakage can be caused by foreign material or if the seat or disc is incorrectly installed. Also, insufficient stem torque in a triple offset valve can result in seat leakage. This is particularly important for the actuator packages, as the actuator has to create the recommended amount of torque to seat the valve. 5. Valve to pipe joint leak can result if the cross tightening of the bolts is not done correctly where the flange is evenly tightened. This can also result if the seal is not properly installed. CRANE PROCESS FLOW TECHNOLOGIES

6. Valve cavitation or vibration occurs, when the valve is being operated too close to the seat. IF so, the Delta P will be too high, which causes bubbles in operation. Therefore, the valve should not be operated or left close to the closed position or cavitation will occur, which can quickly ruin the valve.

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BUTTERFLY VALVES

CRANE BRANDS

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8 Valve & Actuator Online Training Module

Ball Valves

BALL VALVES

LEARNING OBJECTIVES At the completion of this lesson, you will be able to: 1. Given a picture of a ball valve, identify the major components. 2. Identify the following ball valve types: Metal-seated Soft-seated Lined 7. List typical applications for 3. List two primary ball valves. ball designs. 8. Identify likely causes for 4. Identify six ball valve problems associated with body configurations. ball valves. 5. Identify three typical types 9. Given a list of ball valves, of stem seals for ball valves. identify the Crane brand or brands that manufacture 6. List advantages and each of them. disadvantages of ball valves.

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TECHNICAL TRAINING

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BALL VALVES

MEET THE VALVE

A ball with a hole that lines up with the inlet and outlet ports Ball captured between two seats in the valve body Rotates 90 degrees to open or shut Normally used for on/off functions Full Port design Wide range of applications

A ball valve is characterized by a ball with a hole that lines up with the inlet and outlet. The ball is captured by two seats and it rotates 90 degrees to open and shut. As with the butterfly valve, and all quarter-turn valves, it turns clockwise to close. So, if the handle is perpendicular to the waterway, then you can rest assured that the valve is closed.

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Alternatively, if the handle is parallel to the waterway, the valve is open. Ball valves are typically used for on/ off functions, but with modifications, a ball valve can be used in modulating or regulating service. Ball valves can be made available in a full port design, and reduced port, and they can be used in a wide range of applications.

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BALL VALVES

COMPONENTS Belleville Washers Secondary Seal Primary Seal Ball Soft Seat

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BALL VALVES

COMPONENTS Mounting Flange Body Joint Seals Tail Piece

Here you can see the Xomox 2-piece ball valve, which is comparable to most ball valves. It has a live-loaded stem with Belleville washers. There is also a primary seal that matches the contour so that it maintains a seal, even if the secondary seal or packing set is removed. The primary seal also has a bevel so that the stem can be moved without breaking the seal, which is a patented design of Crane. The ball valve also has two body joint seals, one made of graphite and one of Teflon. This provides fire safe protection and prevents corrosion leakage. The two-piece body of this valve is made up of the body and tail, and there is also a soft seat and then, of course the ball. CRANE PROCESS FLOW TECHNOLOGIES

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BALL VALVES

KNOWLEDGE CHECK

KNOWLEDGE C HEC K

Can you identify the parts of a ball valve?

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TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

BALL VALVES

VALVE TYPES

Metal Seated

Soft Seated

Lined

During this course, we will discuss the three major types of ball valves: the metal seated ball valve, the soft seated ball valve, and the Teflon lined ball valve.

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BALL VALVES

VALVE TYPES Metal Seated

Here you can see the Krombach metal seated ball valve. In this design, a floating ball is captured between two seats. The Krombach design is pretty unique. Other manufacturers match lap the seat to the ball so that, they fit perfectly together when in the closed position. However, when the valve is opened, they no longer match perfectly, and a fine media could get entrained between the ball and seat when it does close, and the valve won’t last as long.

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Krombach and its supplier, devised a method to make the ball and seats separately to such precise lapping that any seat would perfectly match any ball, not only in the closes position but in the open position, as well. This increased the life of the product, especially in critical applications. This process was most costly, so to make it more competitive, Krombach designed a unidirectional version where the seat is only on one side.

TECHNICAL TRAINING

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BALL VALVES

VALVE TYPES Soft Seated

A soft seated ball valve has a seat that is typically made of some iteration of PTFE. It could be reinforced PTFE or modified PTFE which is TFM.

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BALL VALVES

VALVE TYPES Lined

Finally, there is the lined valve. The armor of a lined valve is typically ductile iron, but all the wetted surfaces, in this case, are lined with PFA which, is a meltprocessable Teflon. The design of the valve you see here is a patented top seal that has a one-piece ball and shaft. The ball in a lined valve is located at the pivot

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point and a proprietary seal fits around the ball so that when the ball move downstream, the seal follows it and holds the seal regardless of the movement. This design prevented external leakage, unlike those produced by other manufacturers.

TECHNICAL TRAINING

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BALL VALVES

VALVE DESIGNS TWO TYPES OF BALL VALVE DESIGNS Floating

There are two types of ball valve designs. The floating ball valve and the trunnion ball valve are easily distinguished. If the valve body has a fixed shaft on the bottom, it must be the trunnion ball valve. The floating ball valve has an upper stem only and the ball can have a slight displacement, so it is called a floating ball valve. The trunnion ball valve ball has another stem at the bottom to fix the ball's position, so the ball can’t move. The pressure of the medium realizes the sealing of the floating ball valve. The floating ball is pressed against the sealing surface under the action of pressure to realize sealing. That pressure is relieved going back the other way, preventing excessive pressure from building up inside. This design has a self-relieving seat and seals downstream.

Trunnion Mounted

The trunnion-mounted ball valve design is different in that it does not rely on the pressure to seal because there is a trunnion at the bottom. The ball is, therefore, supported between the bottom trunnion and the top drive trunnion, so the ball is held in place. The seats have enough spring load that the seats themselves seal. The pressure, in this design, helps push the seat on the seal, and that pressure is relieved downstream. The floating ball valve is suitable for medium and low pressure and usually has a small diameter. The trunnion ball valve can be used in high-pressure conditions and is offered in larger sizes. CRANE PROCESS FLOW TECHNOLOGIES

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BALL VALVES

VALVE DESIGNS Floating

Cavity Relief Upstream Side

Seats Tighten

PRESSURE

Upstream Side

Downstream Side This diagram shows the process just described, where the pressure pushes the ball against the seats, and the ball moves to seal. The pressure is relieved upstream, and the seats downstream tighten up.

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BALL VALVES

VALVE DESIGNS Floating

Lower pressure classes Limited to 12” bore size maximum Pressure assisted sealing

Typically floating ball valves are lower pressure because the ball has to withstand the pressure load. Therefore it falls into class or below, and most are class 150 or 300. The bore size of a floating ball valve is technically limited to a maximum of 12 inches, but in actuality is usually is around 6 or 8 inches, especially in soft seated floating valves. Anything above 8 inches becomes so heavy that it

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would be hard to support the ball with soft seats. That would have to be supported with a trunnion. So typically, a floating ball has a bore size of 8 inches, but it can be more significant if there is a unique hollow ball design, although those are unusual. Finally, floating ball valves feature pressure-assisted sealing where the pressure forces the ball downstream.

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BALL VALVES

VALVE DESIGNS Trunnion Mounted

Seats Tighten

Cavity Relief Downstream Side

PRESSURE

Upstream Side

Downstream Side

As for the design of the trunnion ball valve, the ball is held in place, and the seals are pre-loaded. The pressure, you can see on the left causes the seal to tighten.

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TECHNICAL TRAINING

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BALL VALVES

VALVE DESIGNS Trunnion Mounted

Higher pressure classes Largest bore size about 64” Seat is loaded against the ball Lower valve torque Double block and bleed capable

Trunnion ball valves are higher pressure classes and more significant in diameter. These would include pipeline ball valves with up to 64-inch diameters. The valves would be trunnion mounted because the balls are so large that they would need the support of the trunnion. The torque is, therefore, fairly consistent, as opposed to floating ball valves that tend to have a higher torque. Trunnion ball valves can also have a double block and bleed, which means

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depending on the seat loading, there could be sealing on both sides, and venting in the middle. These are used in cases when there can be no leakage of media, for example if there will be a person operating in the vessel. In that case, a double block and bleed will be used to block the media in two places and vent up the middle. That way, even if one seal leaks, it’s not going to get past the other seal.

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BALL VALVES

BODY CONFIGURATIONS

1pc Body-Flanged

2pc Body-Flanged

1pc Body-Top Entry

1pc Uni-Body

2pc BodyThreaded

3pc Body

Ball valves are available in several different body configurations which, you can see here.

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BALL VALVES

BODY CONFIGURATIONS 1pc Body-Flanged

The one-piece body is a reduced port valve where the ball, stem, and packing are one size smaller than the flange.

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BALL VALVES

BODY CONFIGURATIONS 2pc Body-Flanged

A two-piece body flange features a body and tailpiece. 248

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BALL VALVES

BODY CONFIGURATIONS 1pc Body-Top Entry

In a one-piece top entry, the cover and body opening has to be large enough for the ball and seats to fit into it. Therefore, it tends to be a heavy and more expensive valve. When a valve is needed that can be repaired in line. A one-piece top entry valve is used. CRANE PROCESS FLOW TECHNOLOGIES

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BALL VALVES

BODY CONFIGURATIONS 1pc Uni-Body

On the smaller side, there is a one-piece uni-body valve. 250

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BALL VALVES

BODY CONFIGURATIONS 2pc Body-Threaded

And here you can see the two-piece body which is threaded with a screw joint between the 2 halves. CRANE PROCESS FLOW TECHNOLOGIES

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BALL VALVES

BODY CONFIGURATIONS 3pc Body

And finally, there is the three-piece body valve. In this last valve, the center section contains the ball, stem, and packing. The two end pieces can be in various configurations, including threaded, butt weld, socket weld, or socket weld, but whatever the configuration, the center section stays the same. 252

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BALL VALVES

STEM SEALS

O-Ring

Stuffing Box

Dual O-Ring Stuffing Box

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BALL VALVES

STEM SEALS O-Ring

The O-ring is a general-purpose seal that would be used for hot and cold water and HVAC systems. It is very utility-oriented and is typically used on the smaller one-piece or two-piece valves. 254

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BALL VALVES

STEM SEALS Stuffing Box

Gland Follower Design

Threaded Stem Design

PTFE chevron (corrosion) or graphite (fire-safe) Live loaded capability Adjustable if leaking Typical for process industries

The stuffing box is one of the requirements for the chemical process industry and is most widely used there. Most of the valves are fire safe, and even the soft seated valves are fire tested. So, if PTFE is present and the fire burns it out, the pressure pushes the stem up, and seals metal-tometal with the body of the stem against the body. Chevron packing is most typically used in these designs, and most designs are adjustable, so if there is leakage, the gland follower or the threaded nut can be adjusted, and can tighten the packing more. This allows for inline repair.

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BALL VALVES

STEM SEALS Dual O-Ring Stuffing Box

Fugitive emission Graphite (fire-safe) Typical for API-6D

We showed this design in the intro. We talked about how this is very familiar in typical for that API 6B/6D is the pipeline ball valves. The dual o-ring stuffing box design is more suitable for ambient temperatures and applications involving many petrochemicals going through the pipelines. At the top, there is a stuffing box that would have a graphite ring that provides the fire testing capability. This stem seal also has an anti-static capability. 256

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In this one, there is a ball loaded on a spring that provides continuity from the stem to the body. Another connection between the stem and the ball would typically have that same type of design or something similar to ensure continuity between the ball, the shaft, and the body. This prevents the buildup of static electricity between the body and the ball, which could cause a static discharge and spark. So this antistatic device ensures that the electrical continuity is maintained between the ball, to the stem to the body.

TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

BALL VALVES

STEM SEALS Crane patented stem seal

Triple Stem Seal

Here you can see the Crane patented stem seal on the metal version. When designing this stem seal, we understood that the ball could flow downstream but also that the stem could be sideloaded, which occurs with valve automation. However, here that stem is moved a little bit the ball follows that movement maintaining is the seal. CRANE PROCESS FLOW TECHNOLOGIES

When this valve was designed, it was with the intent of trying to improve our fugitive emissions characteristics. The lined ball valve came after this and used that same principle differently. In that valve, the ball is moving instead of the top stem, but the same ball-sealing concept applies, a great example of innovation driving results for our customers. TECHNICAL TRAINING

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BALL VALVES

ADVANTAGES/ DISADVANTAGES Advantages

Disadvantages

High flow coefficient (Cv or Kv) Quarter-turn High pressure and temperature Cost-effective Long service life Piggable

Ball valves present several different advantages. A high flow coefficient is one. In a dull port ball valve, the porch opening through the ball valve looks just like the pipe, and you can’t get a higher Cv from a valve than that. Quarter turn capacity is another advantage, allowing for a 90° simple operation. Ball valves also have high pressure and temperature thresholds, are cost-effective, have long service lives, and are piggable.

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Not good for throttling Significant torque to operate (floating) Cavity between the ball and the body

Ball valves have three notable disadvantages. First, they are not typically good for throttling, although they can be used for crude control, but if precise control is needed, then so is a special trim. They also have significant torque to operate, especially in the floating ball valve, because as the pressures increase, so does the torque. And finally, there is a cavity between the ball and the body. What do I mean by that? If you remember, the ball is floating between two seats or the ball is captured in a trunnion with the seats. But when it’s in the open position, and there is a slurry, when it closes, that slurry is cashed in the ball and is now in the body cavity. When the slurry stops moving, it settles and starts collecting below and around the ball, and then when the valve opens, it doesn’t have an opportunity to flush all the slurry out. So then, each time it closes, more slurry or sediment collects and settles, and over time, it can actually lock up and increase the torque so that the valve is inoperable. To address this issue, valve manufacturers have developed cavity fillers that sit around the ball in an attempt to fill that cavity so that not as much of the slurry or sediment can settler. These fillers help but don’t really solve the problem because unless the ball has a tight fit, which would increase your torque tremendously. There are still areas there for the sediment to settle into.

TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

BALL VALVES

APPLICATIONS Metal Seated

High temperature and pressure Autoclaves, delayed coker systems Solids and slurries Cryogenic applications Ball valves can be used in various applications. Metal-seated ball valves are typically used in high temperature and pressure applications, which include autoclaves and delayed Coker systems. They are used in the presence of solids and slurries, but, as discussed, settlement buildup is a concern. And finally, they can use them in Cryogenic applications since expansion is not a concern with the metal seat.

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BALL VALVES

APPLICATIONS Soft Seated

Standard utilities including gas and water General chemical industry Fugitive emissions Low temperature steam

Soft seated ball valves are used in standard utilities, including gas, water, general chemical industry, fugitive emissions, etc. So soft seated ball valves are used pretty much everywhere.

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TECHNICAL TRAINING

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BALL VALVES

APPLICATIONS Lined

Water treatment Acids and corrosives Chlorine Lined valves are used in water treatment applications, as well as with acids, corrosives, and chlorine. As with all lined valves, there is the advantage of corrosion resistance. To get the same level of resistance with an allmetal valve, Monel, Inconel, or some exotic alloy that is very expensive would have to be used. However, with Teflon-lined valves, even though the Teflon is very expensive, it’s being used as a liner, and the valve is being armored with a ductile iron material which is low cost, so it is very economical.

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BALL VALVES

PROBLEMS & CAUSES Valve does not open/shut on demand Physical blockage, corrosion, broken actuator, broken stem

Valve partially strokes but does not reach desired position Excessive stem load due to packing or seat friction, actuator problems

Stem packing/seal leakage Normal wear, inadequate packing/seal loading, incorrect installation, incorrect packing set, inadequate packing consolidation, side loading

Seat leakage Foreign material, seat/ball damaged, seat/ball repaired/installed wrong

Valve cavitation/vibration Operating too near the valve seats 262

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BALL VALVES

PROBLEMS & CAUSES Seat leakage Foreign material, seat/ball damaged, seat/ball repaired/installed wrong

Body joint/Valve to pipe joint leakage Wrong bolt torqueing, scratched sealing surface, wrong seal used, seal not properly installed

Excessive packing/seal friction Over tightened adjustment nuts, incorrect installation

Damaged stem/stem to disc attachment Excessive loading, weak-link design calculation wrong

Flow obstruction Fluid system contains solids (rivers, lakes, seawater), tools or other debris left in system, parts from upstream components CRANE PROCESS FLOW TECHNOLOGIES

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BALL VALVES

CRANE BRANDS

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9 Valve & Actuator Online Training Module

Plug Valves

PLUG VALVES

LEARNING OBJECTIVES At the completion of this lesson, you will be able to: 1. Given a picture of a plug valve, identify the major components. 2. Identify the following plug valve types: Sleeved Severe Service Lined Eccentric Wedge Lubricated 3. List advantages and disadvantages of plug valves. 4. Identify typical applications for plug valves.

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5. Identify likely causes for problems associated with plug valves. 6. Define, “Cold Flow.” 7. Define, “Delayed Coking.” 8. Given a list of plug valves, identify the Crane brand or brands that manufacture each of them.

TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

PLUG VALVES

MEET THE VALVE

Tapered plug that rotates 90° to open or shut off flow High flow coefficient Cavity free Maintenance free Typically used for on/off applications Top entry provides for in-line maintenance

We’ll start by reviewing the critical characteristics of this valve type. Plug valves are characterized by a tapered plug that rotates 90 degrees to open or shut off flow. The standard functionality is clockwise to close and counterclockwise to open. Plug valves are also cavity-free. In a sleeve plug valve, the sleeve is fully encapsulated, so when it closes, the media is trapped inside the ball plug and can’t settle down below.

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Plug valves are typically used for onoff applications, though we will discuss a certain option that makes sleeve plugs applicable for modulating applications. And finally, plug valves have a top entry that allows for inline maintenance.

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PLUG VALVES

MEET THE VALVE

Dates back to ancient times Design is of unknown origin Early plug’s made of wood or animal materials Later designs were metal seated with lubricants to seal

Here, you can see a an ancient plug design that was used to tap a beer keg, but evidence shows that plug valves date back to ancient times. There were Greek records that show the use of plug valves, although the location and timing of their origin are unknown. However, we know that early plug valves were made of wood or animal material, and later they became metal seated with lubricants to provide the seal. 270

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TECHNICAL TRAINING

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PLUG VALVES

VALVE TYPES Sleeved Plug

After the advent of PTFE, the sleeved plug valve was introduced. However, this didn’t occur until after World War II when DuPont made this top-secret material became available for purchase to the public, but up to that point this design did not exist. C.L. Reed invented the sleeved plug valve concept. CRANE PROCESS FLOW TECHNOLOGIES

He worked for Lunkenheimer, a valve manufacturer in Cincinnati, manufacturing gate globe and check valves. When the company was not interested in pursuing and developing his idea, he turned to his father for financing and started his own company which was the start of Xomox in 1956.

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PLUG VALVES

VALVE COMPONENTS Seal Adjustment Bolts Secondary Seal

Top Cover Primary Seal

Sleeve

Plug In a sleeved plug valve, the plug fits into a Teflon sleeve which fully encapsulates the plug. This valve has a primary seal around the port, another at the top, and a third around the bottom. So the plug is captured both in the external seal and through the port. Plug valves have adjustment bolts to adjust the plug. It is one of the few valves

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that allow for the adjustment of the inline seal without having to take apart the valve. So, the valve can be adjusted in the field to stop leakage by adjusting and turning those adjustment screws, then driving the plug further into the taper and adjusting the seal in line, which is an advantage in many applications.

TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

PLUG VALVES

KNOWLEDGE TEST

KNOWLEDGE C HEC K

Can you identify the parts of a plug valve?

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PLUG VALVES

DEFINITION COLD FLOW Cold flow occurs when PTFE “flows” into areas of a valve where it is not desired I mentioned cold flow at the start of this course. Cold flow occurs when PTFE flows into an area of the valve that is not desired. A lot of materials can have this effect. In old buildings, for example, you may see the glass start to look wavy, because over time, the glass cold flows and moves. Materials, mainly plastic materials, tend to cold flow more in higher temperatures. Modified PTFE has a lower propensity to move, or cold flow, than standard PTFE, but PTFE will move under load. The image you see here is a competitor valve without 360-degree port lips. Unfortunately, it does not have any containment for that Teflon, so it actually moves into the port opening and when the plug turns it grabs that Teflon, rendering the valve unfunctional. Competitor’s Valve Without 360° Port Lips 274

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PLUG VALVES

VALVE TYPES Sleeved Plug Cast Top and Bottom Stops

Integral Cast 360° Port Lips

• Prevents sleeve extrusion

• Prevents sleeve turning • Prevents cold flow • Acts as a “scraper”

With the Xomox sleeve plug valve valve, there are lips around the port opening and the top and bottom that help contain the Teflon and help to prevent cold flowing. So as the Teflon tries to flow, it is stopped by the lips, thus reducing the propensity for cold flow.

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PLUG VALVES

VALVE TYPES FORCE

Sleeved Plug Sealing Primary Seal

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Sleeve is compressed between body and plug taper

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The sleeve of a sleeved plug valve is compressed between the body and the plug taper, which you can see diagrammed here. So, without the secondary seal or the cover, as long as the plug is pressed down, the plug is pressurized and the primary seal keeps the media inside. So the primary seal holds the pressure. |

TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

PLUG VALVES

VALVE TYPES Sleeved Plug Sealing

Standard top seal acts as a stem seal as well as a cover bonnet seal Standard top seal is a true secondary seal to atmosphere Standard Top Seal

A secondary top seal is a diaphragm that seals at the outside edges, between the cover in the body, and between the stem.

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VALVE TYPES Cage designs

Cage protects sleeve during plug rotation Ideal for high velocity and severe throttling applications

An available option for plug valves is a cage design. The cage protects the sleeve during plug rotation. It’s ideal for high velocity and severe throttling applications, as well as with slurries.

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VALVE TYPES Throttling flow with a cage

Open

Throttle

A cage fits inside the plug to prevent the intrusion of media. The first diagram shows the valve in the fully open position. As the plug turns, the media flows through sideways, but with the cage present, instead of hitting the sleeve, it hits the cage and then continues to flow through. So, you can see that as the plug throttles the flow, the media does not influence, as the cage prevents it from directly hitting the sleeve. The third diagram shows the closed position where the cage is fixed in position and the valve is closed. So, in terms of throttling, plug valves are used in many slurry applications because of the lack of cavity, preventing any slurry settling when the valve is fully CRANE PROCESS FLOW TECHNOLOGIES

Closed

closed. And with the cage and the intermediate positions it creates, the media will not hit the sleeve. This is particularly important, as Teflon does not handle erosion well. Repeated or continuous contact with a slurry and Teflon will eventually erode away. But the cage prevents that and directs the slurry downstream. The applications for cages are relatively small, but it is beneficial in those applications that have very corrosive materials and don’t require precise control. However, though the applications are limited, cage valves do well in the practical niche applications.

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VALVE TYPES Plug Trim designs

100%

50%

12.5%

Another plug valve design option is the plug trim. These can be used to characterize the trim output, similar to how a ball valve operates. Though plug valves are not generally used for control because of the high brake torque.

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Modified V-Port

PLUG VALVES

VALVE TYPES Multi-port Plug

3-Way

4-Way

Plug valves are also available as a multi-port option. Here you can see a three-way plug valve that can be used for mixing. With this valve, two different medias can flow through or be diverted. And then there is also a four-way version. So this valve comes in various configurations.

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VALVE TYPES Severe Service Sleeved Plug

Separate Plug/Stem Live Loaded, Double Packed Stem Optional Bleed Off Port Shrink Seal in Both Packing and Cover O-Rings at Cover Additional testing and documentation

One of those variations is a severe service valve. These were developed in the early 1980s to solve a customer's problem with liquid chlorine loading stations. The problem was that as the liquid chlorine was loaded into a tanker, the ambient temperature would be very high, and everything would seal. Still, when the cryogenic hit it, the soft seals contracted faster than the metal, which led to chlorine leakage. So Xomox developed this severe service valve design that separated the plug

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from the stem. Features include Belleville washers live loading the packing, an optional bleed-off port so that the valve could be monitored and any leakage through the primary seal could be detected, a shrink seal in both the packing and cove, and additional O-rings at the cover. Additional testing and documentation is done above and beyond what is normally conducted as part of the benefit of using this valve.

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VALVE TYPES Severe Service Sleeved Plug

Separate plug and stem Compensates for plug movement due to high pressure differentials while closed Stem remains concentricwith packing Eliminates side loading ofstem packing Maintains stem seal to atmosphereduring pressure differentials

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VALVE TYPES XP Design Sleeved Plug

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Extending packing cover Patented “shrink seal” Independent plug adjustment Live loaded packing Optional bleed-off port

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Another version is the XP Design, a precursor to the severe service valve. If the higher-pressure differentials were not an issue, this valve could be used. It features an extended packing cover, the same patented shrink seal we just discussed, an independent plug adjustment, live-loaded packing, and an optional bleed-off port.

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VALVE TYPES XP3 & XP4D Fugitive Emission Focused

XP3 – First sleeved plug valve capable of passing ISO 15848’s four (4) thermal cycles w/o packing adjustment XP 4D – Additional set of packing/bolting allows for a manual override of the seal to atmosphere

Today, the XP3 and the XP 4D valves are fugitive emission focused. These were the first sleeved plug valves capable of passing ISOs 15848’s four thermal cycles without a packing adjustment. And the 4D was capable of that with a set of additional packing and bolting, which allows for a manual override of the stem seal and venting to the atmosphere. These valves were part of a Crane initiative to focus on new product development with fugitive emission requirements to meet or exceed the demands of our customers.

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3PX

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VALVE TYPES Lined Plug

Large seal area Tight shut-off Long life

The next valve we will discuss is a lined plug valve, a ductile iron armored valve. This valve, including all the wetted parts, is fully PFA-lined. It is known for its tight shutoff and long life. This valve is similar in concept to the sleeve plug valve, but the lining, in essence, becomes the sleeve, and the plug is lined as well.

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PLUG VALVES

VALVE TYPES Eccentric Plug Manual Operation Bare shaft 2” drive t-key Lever Chain wheel Gearbox Automated Operation Electric Pneumatic Hydraulic Cylinder Multi-Functional Isolation Regulation Bi-directional

The eccentric plug valve is a Viking Johnson design that is typically used for sewage, water, wastewater, and the like. It has a rubber-lined eccentric disc or plug and is available in manual and automatic operation configurations. This valve is multi-functional, so it can be used to isolate or regulate, and it’s bi-directional, so it’s very versatile.

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PLUG VALVES

VALVE TYPES Wedge Plug

Wedge torque operator lifts, rotates 90 degrees, and re-seats plug on its protected seating surfaces Open-close position indicator Limit switches Large stuffing box

The wedge plug valve is next, and the one shown here is the Pacific Wedge Plug Valve. It has a particular wedge torque operator that lifts the plug, rotates it, and then pushes it into the seat. This valve also has an open-close position indicator, limit switches, and a large stuffing box.

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PLUG VALVES

VALVE TYPES Wedge Plug

Non-lubricated and tapered plug Robust body with raised seating surfaces Integrally cast body ribs Seven body bosses

The wedge plug has a non-lubricated and tapered plug, as well as a robust body to maintain integrity. This valve is preferred over other valves like the ball valve in steam applications, significantly delayed coking. Steam energizes the connections around the packing area and

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around the body so that as the plug lifts, the steam pressure enters and keeps the Coke from entering the seal area. It then turns and pushes the plug back down so that the steam is only consumed while the plug is turning.

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PLUG VALVES

DELAYED COKING

DEF INITION

DELAYED COKING Delayed coking is one of the unit processes used in many oil refineries. A delayed coker heats a residual oil feed to its thermal cracking temperature in a furnace with multiple parallel passes. This cracks the heavy, long chain hydrocarbon molecules of the residual oil into coker gas oil and petroleum coke.

Delayed coking is a batch process that you can see here. All the valve symbols you see here are where the wedge plugs would be placed along the process, and the drums would be energizing and breaking down the material. The material would then switch to the other, a continuous alternation between the two drums. That is the delayed coking process, and as stated, the wedge plug valve is the go-to valve for this application. 290

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VALVE TYPES Lubricated Plug

Used primarily in oil and gas or other applications where grease contamination is not a problem Lower torque required than sleeve plug valves Sizes ½” to 24” Pressure Class 125 and 250

The following valve type we will discuss is the lubricated plug valve. Again, Crane does not make this valve, but it has always been primarily used in oil and gas applications, as well as those where grease contamination is not a problem.

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This valve features a grease injection port that goes through a series of, labyrinths and keeps the plug lubricated so that it’s able to turn. These valves are available in sizes ranging from half an inch to 24 inches and in pressure classes 125 and 250. TECHNICAL TRAINING

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ADVANTAGES Plug Valves (all)

Simple design with few parts They open and close easily (except large dimensions) Maintenance and repair can be done at the place of operation

They have low flow resistance They provide reliable leak-proofness

There are several advantages that plug valves present. First, they have a simple design with only a few parts. They open and close easily, though the large brake torque we discussed can be an impediment, which would require the use of a manual gear at a smaller size. Maintenance and repair can be done in the field, which is always an advantage. They also have lowflow resistance, and the operator can adjust the leak tightness of the in-line seal externally, which can only be done on a few valves.

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PLUG VALVES

ADVANTAGES Sleeved Plug

No cavity between plug & body Adjustable Seals In-line and external seal Can adjust while installed ¼ Turn of adjustment screws

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TECHNICAL TRAINING

Specifically speaking of the sleeved plug, there are many advantages, including the absence of a cavity between the plug and the body, making it suitable for slurry applications. This valve also has adjustable seals and inline and external seals. Sleeved plug valves can be adjusted while installed, reducing process downtime and saving on valve repair or replacement costs.

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ADVANTAGES Sleeved Plug

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Quarter Turn Operation Easy to actuate Better at controlling emissionsthan a rising stem valve such asa gate or globe Does not “drag” media thrustem packing

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TECHNICAL TRAINING

This valve features a quarter-turn operation and is relatively easy to automate. The sleeved plug valve is better at controlling emissions because it’s a quarterturn valve rather than a rising stem. Therefore, it doesn’t drag the media through the stem packing as a rising stem would.

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PLUG VALVES

ADVANTAGES Full ported option available

Full unobstructed flow High Cv/Kv value Piggable

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There are fully ported versions of plug valves available, offering full, unrestricted flow. Plug valves also have a high Cv and are piggable.

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ADVANTAGES Plug Valves (all)

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Because of high friction, first movement (openingclosing) requires a large amount of force Large valves require a gearbox or an actuator Valve transitions are narrowing flows due to conic plug 4. Generally, their costs are much larger than ball valves CRANE PROCESS FLOW TECHNOLOGIES

Though they have many advantages, plug valves have a number of disadvantages. Because of the high friction involved, the first opening requires a large amount of force. We also discussed these valves' initially high brake torque, which requires a gearbox or an actuator. The standard plug on this valve narrows restricting the flow as it comes in from side to side, so it has a lower flow capacity than a full port valve. And finally, plug valves are generally more costly than ball valves.

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PLUG VALVES

APPLICATIONS

Typically used for on-off but can be used for throttling (with cage) Sleeved plugs Limited pressure/ temperature applications Gas, crude oil, flare stacks HF acid, acetic acid, desulfurization Autoclaves Pulp and paper Severe service – chlorine, phosgene, MDI/TDI

As mentioned, plug valves are typically used for on/ off applications, but with a cage, they can be used for throttling, though there is a niche market for that. Sleeved plug valves can be used in limited pressure and temperature applications due to Teflon or some other polymer sleeve. These applications include gas, crude oil, flare stacks, pulp and paper, HF acid and most industry applications that involve acids, and corrosives. CRANE PROCESS FLOW TECHNOLOGIES

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PLUG VALVES

APPLICATIONS

Wedge plugs On-off only High pressure and temperature Delayed coking Lined plugs Chemicals, corrosives Water treatment Eccentric Plugs On-off and control Sewage, sludge, slurries

Wedge plugs can only be used in on-off applications and are suitable for high pressure and temperature environments. As mentioned, delayed coking is the primary application for wedge plugs valves. Lined plug valves are suitable for applications involving corrosive chemicals and water treatment. Eccentric plug valves are suitable for on-off and control applications, specifically sewage, sludge, and slurries. But, again, that is a Viking Johnson product.

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CRANE BRANDS

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10 Valve & Actuator Online Training Module

Valve Testing

VALVE TESTING

LEARNING OBJECTIVES At the completion of this lesson, you will be able to: 1. Define, “Flow Coefficient.” 2. State the purpose for a Flow Coefficient (Cv / Kv) test. 3. Identify the steps needed to perform a Flow Coefficient (Cv / Kv) test. 4. Given a scenario, identify the data required to calculate Flow Coefficient (Cv / Kv). 5. Using provided data, calculate Flow Coefficient (Cv / Kv). 6. State the purpose of shell and seat leakage testing.

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DEFINITION

DEF INITION

Flow Coefficient (Cv / Kv) The amount of water flow at 60 degrees F, in gallons per minute, at a pressure drop of one pound per square inch across a component.

The flow coefficient is defined as the amount of water flow at 60 degrees Fahrenheit, in gallons per minute, at a pressure drop of one pound per square inch across a component. The result is a dimensionless coefficient that can be used to compare one valve type against another valve type or even one manufacturer’s valve against another.

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VALVE TESTING

FLOW COEFFICIENT (CV / KV)

Flow Coefficient (Cv) is used in the United States Flow Factor (Kv) is used in Europe Kv = (.865)(Cv) Both are used to measure the efficiency of a valve at allowing fluid flow A valve with a high Flow Coefficient has less pressure drop than a valve with a low Flow Coefficient.

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Cv / Kv is one of the parameters used to size a valve The values are determined by testing in a flow loop during the development of the valve and published for use by system designers ANSI/ISA-S75-02 describes basic testing for Cv EN 1267 describes the method for Kv

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VALVE TESTING

FLOW COEFFICIENT (CV / KV) Basic flow test setup

And you can see the flow setup for that test here. It starts with a water source, and contains an upstream throttling valve, a temperature sensor, a flow sensor, pressure taps on both sides of the test specimen, and a downstream throttling valve.

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VALVE TESTING

FLOW COEFFICIENT (CV / KV) ANSI/ISA-S75-02

ANSI/ISA S75 describes the primary test for Cv, and the critical aspect is the ability of the tap to register the correct amount of pressure and the presence of laminar flow or even flow. The specification is that there must be at least 18 nominal pipe diameters of the straight pipe before the pressure tap. So, if you have a 1-inch test specimen and a 1-inch pipe, then there must be 18 inches of 1-inch pipe before the pressure tap. The same goes for a 12-inch valve. There would have to be 18 feet of 12-inch diameter or equivalent diameter pipe prior to the pressure tap. Therefore, the larger the valve being tested, the larger this test loop is. So, to summarize the parameters, there is 18 x [times] the nominal pipe diameter before the pressure tap

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upstream of the test specimen. And then two nominal pipe diameters of straight pipe between the test specimen and the tap. Another six diameters of pipe after the test specimen to the pressure tap downstream, and then at least one nominal pipe diameter of straight pipe before any bend or turn after the pressure tap. The purpose of these strict guidelines is so that regardless of who runs the test or in which lab it is conducted, there is some consistency in the type of results generated. And that applies within Crane, as we have several facilities with flow testing capability. This is the basis for that calculation that’s used universally to develop the Cv in the U.S. and the Kv in Europe.

TECHNICAL TRAINING

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VALVE TESTING

FLOW COEFFICIENT (CV / KV) Basic flow test setup Valve to be tested set to desired position.

Temperature confirmed to desired reading.

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VALVE TESTING

FLOW COEFFICIENT (CV / KV) Basic flow test setup Valves adjusted to desired gallons per minute (GPM).

GPMs

Readings taken to determine difference between upstream and downstream pressure.

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VALVE TESTING

FLOW COEFFICIENT (CV / KV) Calculating flow differential (Cv) Then, this formula is used to calculate the flow differential. Here, the Cv is equal to the flow rate times the specific gravity divided by the pressure drop across the valve.

Specific Gravity (for fluid used)

Flow Rate (Gallons Per Minute – GPM)

GPMs

Q equals the flow rate in Gallons Per Minute obtained from this flow sensor. CRANE PROCESS FLOW TECHNOLOGIES

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VALVE TESTING

FLOW COEFFICIENT (CV / KV) Calculating flow differential (Cv)

Specific Gravity (obtained from known data)

The specific gravity is obtained from a data chart based on the fluid and the temperature.

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VALVE TESTING

FLOW COEFFICIENT (CV / KV) Calculating flow differential (Cv)

In this case, the specific gravity of water at 60 degrees Fahrenheit is 1

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VALVE TESTING

FLOW COEFFICIENT (CV / KV) Calculating flow differential (Cv)

The Delta P is the difference between the upstream and downstream pressure.

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FLOW COEFFICIENT (CV / KV) Calculating flow differential (Cv)

Water

80 PSI

60 PSI

60 Degrees F

So, in this example, the water at 60 degrees Fahrenheit is flowing at 225 gallons per minute with 80 psi Upstream and 60 PSI Downstream.

50.3 To calculate the flow differential with all of this data, you start with 225 as the flow rate. One is the specific gravity. The Delta P is calculated by subtracting 80 - 60 which equals 20. So the Cv is calculated as 50.3. CRANE PROCESS FLOW TECHNOLOGIES

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FLOW COEFFICIENT (CV / KV) AC T I V I T Y

It is time for you to calculate the Cv value for a valve.

Water

120 PSI

95 PSI

60 Degrees F 320 GPM

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FLOW COEFFICIENT (CV / KV) Use the information from the previous slide to solve the equation.

LET’S CHECK YOUR WORK:

64 For this example, the flow rate is 320. The specific gravity is one, and the Delta P is calculated at 120 minus 95, totaling 25. The square root of .04 is .2, so the Cv here is 64.

WHAT IS THE SAME VALUE FOR Kv?

Kv = .865Cv

Kv = 55.36

To then calculate the Kv, you would multiply the Cv by .865 which totals 55.36.

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VALVE TESTING

KNOWLEDGE TEST Why find the Cv or Kv values for a valve? It is one of the determining factors for sizing a valve.

What values are needed to calculate Cv?

Flow rate Specific gravity of the fluid Pressure difference

In summary, the reason that we find the values of Cv or Kv is because it is one of the determining factors for sizing a valve, and allows for comparing one valve against another or one manufacturer against another. And the values needed to calculate the Cv is flow rate, fluid's specific gravity, and pressure differential. Cv is an essential criterion for sizing a valve.

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VALVE TESTING

SHELL & SEAT LEAKAGE Basic steps for testing

Install the valve in the test fixture with sufficient clamping force to prevent leakage

We’ll now shift away from Cv testing that happens in a laboratory and witch to basic shell and seat leakage testing. Several steps that must be followed on this type of test. First, the valve must be installed into the test fixture with sufficient clamping force to prevent leakage.

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VALVE TESTING

SHELL & SEAT LEAKAGE Basic steps for testing

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Vent the valve while filling to remove air pocket Pressurize the valve to the required pressure and hold for the required time Verify that the leakage criteria is met

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For the shell test, the valve is vented through a vent at the highest location of the valve to exhaust all the air while it’s being filled with liquid, thus removing air pockets that could be present. This is one of the critical criteria of the shell test because the air needs to be completely evacuated to ensure there is no compressible fluid in there that could potentially explode should something go wrong with the valve. So, once all the air is evacuated, the valve is pressurized and held to verify the leakage criteria are met.

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VALVE TESTING

SHELL & SEAT LEAKAGE ASME B16.34 Testing requirements

High Pressure Shell Test (1.5 times the rated valve pressure @ 100OF) High Pressure Seat Closure Test (1.1 times the rated valve pressure @ 100OF) Low-Pressure Seat Closure Test not less than 5.5 bar (80 psi)

The ASME B16 34 is the design and test standard for valve designs and consists of several tests.

drain the equipment, close the valve, add the pressure, and conduct the low-pressure seat closure test at 80 psi. The shell and low-pressure seat closure tests must be performed on every manufactured valve.

The high-pressure shell test is one and a half times the rated pressure at 100 degrees Fahrenheit.

And during the design process, the high-pressure seat closure test is an essential requirement that must be done during the development phase of every valve.

The high-pressure seat closure test is 1.1 times the rated valve pressure. The testing requirement calls for a 1.1 seat closure test during the valve design and initial testing process. This is to ensure there is no permanent deformation of any parts and that it works at that 1.1. point one. That is a validation test required during the design process. Beyond that, there is also a low-pressure seat closure test of not less than 5.5 bar or 80 psi. So, within Crane across all of our valves, we conduct a high-pressure shell test with water at one and a half times the pressure. We then CRANE PROCESS FLOW TECHNOLOGIES

Shell and seat closure tests to be performed for the times designated A backseat test is required for gate & globe valves, except for bellows seal, that have the backseat feature

The shell and seat closure tests are performed a designated number of times. A backseat test is also required for gate and globe valves, excluding bellows valves. This applies to these valves because they have a backseat feature, or a bevel on the stem that goes up and meets the body or the backseat bushing in the bonnet and seals.

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VALVE TESTING

SHELL & SEAT LEAKAGE ASME B16.34 Testing requirements

Valves: Flanged, Threaded, and Welding-End

Shell Test Duration

Closure Test Duration

As part of this test, shell test duration and closure test duration standards are based on the valve size.

larger-sized valves have thicker wall sections, and it would take longer before the liquid might fight its way through the shell, so that it can sit at that pressure for a longer time.

The NPS refers to the nominal pipe size. For the shell test, when the NPS is less than 2 inches, the test time is 15 seconds. For an NPS greater than 2.5 inches and less than 8 inches, the test time is 60 seconds, and when the NPS is greater than 10 inches, the test time is 180 seconds. The idea here is that the

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The closure seat test is the same but with slightly different parameters as far as four ratings or four various differentiation of size, but the concept is the same. Therefore, the test pressure can remain at these durations listed here based on the size.

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SHELL & SEAT LEAKAGE BS EN 12266-1 Testing requirements

High Pressure Shell Test(1.5 times the rated valve pressure @ 20OC) High Pressure Seat Closure Test(1.1 times the rated valve pressure @ 20OC) Low-Pressure Seat Closure Test (5 – 7 bar air) Shell and seat closure tests to be performed for the times designated Seat closure tightness shall be agreed upon by the manufacturer and purchaser From the European standpoint, the BS EN 12 2 66 has those exact testing requirements but at the metric equivalent of the imperial Pressure and temperature. As you can see, this standard pretty much mirrors the standard of ASME B1634.

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VALVE TESTING

SHELL & SEAT LEAKAGE BS EN 12266-1 Testing requirements

The same applies to the shell and seat tightness tests. Again, the timing across the sizes pretty much mirrors exactly the ASME B16 34 standard.

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SHELL & SEAT LEAKAGE BS EN 12266-1 Testing requirements

One difference between the ASMEE standard and BS EN 12 2 66 is that the latter has a different leakage criteria based on the design. Here, an A rating means there iis no visually detectable leakage, which is the he standard leak rate for any soft seated valve valve because the allowable leak rate is essentially zero.

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VALVE TESTING

KNOWLEDGE TEST

Why test a valve at 1.5 × its pressure rating? This ensures a safety margin.

Knowledge Check. Why test a valve at 1.5 times its pressure rating? Because it’s a factor of safety that ensures a safety margin. So, if the valve is functional at 285 PSI, for example, and the test is done at oneand-a-half times that, and it still works without deformation or leakage, then it can be said the valve is safe to use.

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11 Valve & Actuator Online Training Module

Actuators

ACTUATORS

LEARNING OBJECTIVES At the completion of this lesson, you will be able to: 1. Describe the purpose of an actuator. 2. List two categories of actuators used by Crane. 3. Define, “Thrust.” 4. Define, “Torque.”

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ACTUATORS

ABOUT ACTUATORS

Actuators are used to automate of industrial valves to open or close or move to a desired position.

Actuators are used to automate industrial valves to open or close them or move them to athe desired position. The first valve you see on the screen is a FlowSeal High-Performance Butterfly Valve with a manual gear override and an alematic, or rack and pinion, an actuator with a switch box on top, which is a typical on-off automated package. The second is a Centerline 200 valve with a Vane actuator, which is a type of pneumatic actuator.

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ACTUATORS

TYPES OF ACTUATORS Crane uses two main types of actuators:

Electric

Pneumatic (air)

Crane primarily utilizes two main types of actuators: electric and pneumatic. Here, the electric actuator is on top of a resilient seated butterfly valve, and the pneumatic actuator shown here, which is a Saunders product, is sitting on top of a Saunders industrial diaphragm valve.

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TYPES OF ACTUATORS

An electric actuator and a valve are called a motor-operated valve or “MOV.”

In the power industry, when a valve is connected to an electric actuator, it is called a Motor Operated Valve or MOV.

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ACTUATORS

TYPES OF ACTUATORS

A pneumatic actuator and a valve together is called an air-operated valve or “AOV.”

And when a pneumatic actuator is connected to a valve, it is called an air-operated valve or AOV.

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DEFINITION FORCE

DEF INITION

Thrust The linear force needed to move the valve’s working element.

A term you will need to know when discussing actuators is “thrust”, which can be defined as the linear force required to move the valve’s working element. For example, on the valve that is pictured here which is a slab gate valve, thrust is the force required to move the slab up and down.

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DEFINITION FORCE

D E FI NI TI ON

Torque The rotary force is needed to move the valve’s working element.

Another term you should be familiar with is “torque”, which is the rotary force needed to move the valve’s working element. Therefore, all rotary valves will have a torque requirement to automate them.

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ABOUT ACTUATORS Why use an actuator on a valve?

Large amount of thrust or torque required Difficult access to the valve Unique throttling or positional requirements Integration into advanced operating systems Emergency operation response

You may be wondering why an actuator would be used on a valve. Actuators are essential in several different circumstances. When a large amount of thrust or torque is required, an actuator is what helps to move the valve. For example, in the case of a large 48-inch gate valve, turning the hand wheel would require a lot of effort, but with an electric actuator, the wheel is turned automatically via the actuator. The same would apply to a rotary valve with a pneumatic actuator. Actuators are also helpful if it is difficult for the operator to access the valve manually, whether because of its location or if the environment is toxic or hot. Another reason to utilize actuators is unique throttling or positional requirements. The majority of throttling valves, or control valves, are automated. CRANE PROCESS FLOW TECHNOLOGIES

Today, many plants are highly automated and have advanced operating systems that control the valves in service, especially on/off and control valves. In these cases, automated valves are used a central control algorithm can control that. Also, more and more plants are integrating advanced safety systems with dedicated valves that have the ability to safely shut down the plant rather than relying on the fail close or fail open features of the in-line valves. This emergency operation response would require the use of actuators.

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Pneumatic Actuators

PNEUMATIC ACTUATORS

LEARNING OBJECTIVES At the completion of this lesson, you will be able to: 1. Identify the following pneumatic actuator types: Diaphragm Piston Rack-and-Pinion Vane Scotch Yoke 2. Identify typical applications for pneumatic actuators. 3. Identify the Crane brands that manufacture pneumatic actuators.

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ACTUATOR TYPES

Diaphragm

Diaphragm Plate

Actuator Stem Actuator Spring Spring Adjustor

Spring Seat

Travel Indicator Disk

Indicator Scale

This is what the inside of a diaphragm actuator looks like, in this case, a springto-close actuator. So, as the spring pushes down, the air pushes the diaphragm up, the air is exhausted, and then the diaphragm pushes down. Most diaphragm actuators have two stems, and various arrangements for the spring.

The first type of pneumatic actuator we will discuss is the Diaphragm Actuator. Here you can see one placed on top of a globe valve. Diaphragm actuators are utilized on globe valves as well as diaphragm valves, but typically not on gate valves due to their longer stroke.

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ACTUATOR TYPES Piston

Used to automate rising stem linear valves Capable of automating valves with long strokes Simple and easy to maintain Can handle higher supply pressures than linear diaphragm actuators

The next type of pneumatic actuator we will discuss is the Piston. A piston is used to automate rising stem linear valves and can automate valves with long strokes. Therefore it is typically used on gate valves. The piston actuator has a simple design that is easy to maintain and can handle higher supply pressures than linear diaphragm actuators.

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ACTUATOR TYPES Piston

Large volume results in actuators requiring more supply media volume to operate as compared to linear diaphragm or rotary actuators Commonly used where moderateto-high supply pressures are available and long valve strokes are required

Compared to a linear diaphragm or rotary actuators, piston actuators typically require more supply media volume to operate. They are also commonly used where moderate-to-high supply pressures are available, like a PSI, for example, and long strokes are required.

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ACTUATOR TYPES Piston

Top Cylinder Pressure

Bottom Cylinder Pressure

Fail Closed

Fail Open

Here you can see the inner workings of a fail closed and fail-open design. The diagram on the left shows the fail close, so the spring inside the cylinder would push down to close the valve. When air is added to the side, the piston is pushed up, lifting the valve and opening it. The air would then be exhausted and flow back down. When the spring is on the bottom side, that function reverses, and the air is added to the top, which closes the valve, and when the air exhausts, the valve opens. In many cases, on larger pistons, there is a separate cylinder with a spring cartridge mounted on top.

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ACTUATOR TYPES Rack-and-Pinion

Compact design Double acting Spring return / fail safe Constant travel torque Limited torque range Variable torque output for single acting actuators

The next type of actuator is a rack and pinion. You may be familiar with this term, as it is also used in automobiles. For example, when you turn the steering wheel, there is a pinion on the end of a turning rack. That rack is connected to your wheels which is how the wheels turn. Here, in the case of a quarter-turn actuator, the concept and functionality of the rack and pinion are the same. Rack and pinion actuators are compact and are either double-acting or CRANE PROCESS FLOW TECHNOLOGIES

single-acting, also known as spring return. Though the double-acting have a constant travel torque, rack-and-pinion actuators have a limited torque range. For spring return, there is variable output. Rack and pinions probably represent 90% of valve automation for most ball valves, plug valves, and smaller highperformance butterfly valves. They are relatively economical to manufacture and are simple in makeup.

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ACTUATOR TYPES Rack-and-Pinion

Open: Air at “A” causes counter-clockwise rotation. Close: Air at “B” causes clockwise rotation.

This is a double-acting rack and pinion actuator, and within this type, when pressure is added to the “A” location (or the inside), the pistons are pushed out, which turns the rack counterclockwise. When pressure is added to location “B” (or the outside), the pistons are pushed in, turning the rack clockwise. So as you can see, it’s a fairly simple design made up of only three moving parts: two pistons and a pinion. 344

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ACTUATOR TYPES Rack-and-Pinion

Open: Air at “A” causes counter-clockwise rotation. Close: Springs cause clockwise rotation and force air out

A For a single-acting rack and pinion actuator, most designs use the same end caps, the same pistons, and the same pinion, but springs are added. In this configuration, the air is added to the inside, pushing the pistons out, turning the rack counterclockwise, and compressing the springs. When air is exhausted out of the “A” location, the springs push the racks in and turn the pinion clockwise. So, this would be a fail clockwise/close rack and pinion. CRANE PROCESS FLOW TECHNOLOGIES

So, if a fail counter-clockwise or fail open rack and pinion is needed, then the actuator would be disassembled, and the pistons would be flipped so that when it is pushed in, the pinion turns counterclockwise. Instead of having a fail close design, you would have a fail counterclockwise/open rack and pinion, made with the same actuator components, just assembled differently.

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ACTUATOR TYPES Rack-and-Pinion

Racks (cylinders)

This is what the racks and pinions look like on this actuator type.

Pinions 346

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ACTUATOR TYPES Torque Output

The torque output remains constant throughout the valve stroke Both the forces generated by the pistons remain constant The distance between the pistons forces and the pinion remains constant

As mentioned, the torque output is constant, which means that along the entire stroke from full closed to fully open, and back to closed, the torque remains constant. As you may remember, torque is force times distance, and in this case, it stays flat and does not vary throughout the entire stroke.

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ACTUATOR TYPES Rack-and-Pinion This is the Revo actuator which is made by Crane. The Xomox brand also offers this same actuator, called the Xomox XRP, but with a blue end cap.

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ACTUATOR TYPES Torque Output

On the air stroke, the torque starts high but linearly decreases as more of the force generated by the piston is used to compress the springs

On the spring stroke the torque starts high but linearly decreases as the springs extend (re: Hooks Law) from their fully compressed position

On the single-acting version of this actuator, some of the pneumatic energy is used to compress the springs so energy is no longer available to turn the valve. Therefore, the torque output starts high during the stroke, and as the spring is compressed, it goes down. So the torque output is linear, but it decreases. But as the spring stroke returns, the springs start fully compressed, and decrease as they relax and turn the pinion. So, there is a pneumatic start, a pneumatic end, a spring start, and a spring end. This is important to remember when sizing the rack and pinion actuator spring return to a valve, as the torque at these four positions must be greater than the torque requirements of the valve plus the safety factor. CRANE PROCESS FLOW TECHNOLOGIES

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ACTUATOR TYPES Vane

Lightweight and Compact One Moving Part Dual Travel Stops Fail Safe System Economic

Next is the vane actuator. This type is lightweight, compact, and has only one moving part. It has dual travel stops, closed and open, and faile-safe systems are available for these actuators.

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ACTUATOR TYPES Vane

Paddle O-Ring

Bronze Bushing

Paddle

Nylon Bearings

Stroke Adjustment The components of a vane actuator are pretty straightforward. As previously mentioned, the vane actuator is made up of two clamshell halves of the cylinder, and there is a paddle seal with the vane. It has the bronze bushing inserted into the diecast mold and the aluminum bolted around it. The shaft is molded integrally with the vane. CRANE PROCESS FLOW TECHNOLOGIES

Xomox makes a vane actuator that is branded as the Matryx. It is used primarily for double-acting applications, those that don’t have a spring return requirement, but where there is a large volume, and a low-cost automation product is desired.

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ACTUATOR TYPES Vane

Most cost efficent design of double acting actuator Few parts and easy to handle

Constant travel torque

Torque

Closed

Travel

With the vane actuator, there is a constant area and a constant moving arm (or vane) that operates in a sweeping motion, creating constant torque throughout its stroke. That clamshell vane is a single piece that is bolted together at the top and bottom and has travel stops at both ends and then.

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Open

PNEUMATIC ACTUATORS

ACTUATOR TYPES Vane

High ratio of torque output per pound of actuator weight Durable die cast aluminum housing

The vane actuators have a high ratio of torque output per pound of actuator weight, and it features a durable die-cast aluminum housing.

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ACTUATOR TYPES Scotch Yoke

Wide torque range Can be used in conjunction with a linear cylinder or a linear diaphragm

The Scotch Yoke actuator is the next type we will discuss. Crane does not manufacture this actuator type, but we purchase them for our valves. “Scotch yoke” refers to the mechanism that converts the linear motion into a rotary motion.

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Often used with ball and butterfly valves

Scotch yoke is the next type. Scotch yoke actuators are talking about the mechanism for converting the linear motion from the piston into a rotary motion. It has an extensive torque range and is often used with the ball and butterfly valves.

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ACTUATOR TYPES Scotch Yoke

Closed

TORQUE

Double Acting

TORQUE

Single Acting

TRAVEL

Open

From a double-acting standpoint, it does not offer a constant torque output. Scotch yoke actuators have higher torques at both ends with lower torque in the middle. With the high brake torque, low run torque, and seating torque, this actuator closely mimics the torque curve and the requirements for ball and butterfly valves.

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Closed

TRAVEL

Open

For sleeve plug valves, it’s a little bit different because the run torque, although lower, is still a higher percentage of the brake torque than it is for ball or butterfly. Therefore, in a plug valve, the spring return cycle, however, looks a little different. It has the same curve, but the lowest point is not in the center. It’s on the end.

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ACTUATOR TYPES Scotch Yoke

Not normally economical for low pressure applications Large and heavy No constant travel torque Limited to valves which do not require morethan 110 degrees rotation

Scotch yoke actuators are not usually economical for low pressure or low torque applications, though some manufacturers have designs that can be. These actuators are typically large and heavy, as they are made of ductile iron or cast iron in the center body section. In addition, scotch yokes are limited to valves that do not require more than 110 degrees rotation. 356

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ACTUATOR TYPES Scotch Yoke Rotation

TRAVEL

Air Inlet

Spring

Air input compresses the spring and drives the scotch yoke mechanism in a scotch yoke actuator. Remembering that torque equals force times distance, the force is the force vector perpendicular to the yoke mechanism. The arm on that force vector is the length you see here. Because it’s 45 degrees at that point, the force

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vector is half the force that this piston is putting out. But the length of the arm here is more than twice the distance from the shaft to the center, so even though the force is halved, the arm is more than twice the distance to the center line of the shaft, which is why there is more torque at each end than there is in the middle.

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APPLICATIONS Pneumatic Actuators

Process control for maintaining flow, temperature, pressure, level, pH, etc. in any type of fluid system

On/off applications requiring low to mid torque or thrust Applications where electrical power is not readily available

Now that you understand the various types of pneumatic actuators let’s review their typical applications. These actuators are typically used in process control for maintaining flow, temperature, pressure level, and pH. They are also used in on/off applications that require low-to-mid thrust or torque, and in applications where electric power is not readily available. 358

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APPLICATIONS Diaphragm

Linear control applications On/off when stem thrust requirement is low

Diaphragm actuators are preferred for linear control applications. This is because of the short stroke, and because they operate very quickly and easily without a lot of friction.

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APPLICATIONS Piston

Linear control applications On/off when stem thrust requirement is high

Pistons are also used for linear control applications, though the diaphragm actuator is typically the preferred alternative. Pistons can also be used in on/off applications when the stem thrust requirement is high, or the stroke is long.

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APPLICATIONS Saunder S360

Smooth corrosion resistant profile optimizes cleanability in hygienic/pharma applications High cycle life, lower air consumption and more compact design versus diaphragm type 316L Stainless Steel Full 360° rotation of actuator head allows flexible installation and air port alignment

Diaphragm actuators are preferred for linear control applications. This is because of the short stroke, and because they operate very quickly and easily without a lot of friction.

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APPLICATIONS Rack-and-Pinion

Compact for restricted space applications Lower torque applications such as butterfly and ball valves

Because of the compact design of the rack and pinion actuator, it is often used in applications that have space limitations. It is also used in lower torque applications such as butterfly and ball valves.

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APPLICATIONS Vane

Applications where torque to weight ratio is important Medium torque applications such as plug valves Applications where failure position is not critical

Vane actuators are used in applications where the torque to weight ratio is important, and those with medium torque levels, such as those where plug valves are used. However, these actuators are also not typically used in applications where the failure position is critical.

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APPLICATIONS Scotch Yoke

Applications where higher torques are required

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Electric Actuators

ELECTRIC ACTUATORS

LEARNING OBJECTIVES At the completion of this lesson, you will be able to: 1. Given a picture of an electric actuator, identify the major components. 2. Identify the following electric actuator types: Multi-turn Quarter-turn 3. Identify typical applications for electric actuators. 4. identify likely causes for problems associated with electric actuators. 5. Identify the Crane brands that manufacture electric actuators.

During this lesson, we will review the major components of an electric actuator, identify the various types, discuss the typical applications and review the likely causes and problems associated with electric actuators. 368

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ACTUATOR TYPES Two types of electric actuators:

Quarter-Turn (worm or spur gear) Multi-Turn (worm gear)

Quarter-Turn

Multi-Turn

There are two types of electric actuators: quarter turn and multi-turn. Quarter turn actuators can be worm-gear driven or spurgear driven, which we will explain briefly. This actuator type is usually used on valves such as ball, butterfly, or plug valves, as

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it helps when a valve needs to turn 90 degrees to open fully.. The Multi-Turn actuators are always wormgear driven. IT is typically used on linear valves where many rotations are needed to open the valve.

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LEARNING OBJECTIVES Spur Gear

Quarter-Turn actuators only

Spur Gears

As mentioned, a spur gear is only used on quarter-turn actuators. This is because it provides the torqueing leverage of a small motor. Ultimately, when used where the horsepower energy of a motor is deficient, the spur gears can produce a torque output that could be significant but turn very slow So, it takes the high-speed, low torque motor into a low torque, high-speed output. Spur Gears can be easily driven or turned in either direction, which is particularly 370

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useful on a ball valve or plug valve. This is because nothing on a ball valve will try to drive the actuator, and once the actuator on a plug valve stops, the plug will not continue to move. This type of actuator, however, would not typically used on a butterfly valve because the hydrodynamic torque would continue to drive it, as there is nothing in the valve that would stop the spur gear from operating in either direction.

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ACTUATOR TYPES Worm Gear Stem

Worm Gear Motor

Spring Pack Worm Torque Switch Limit Switch Here you can see the worm-gear actuator. The worm gear is located in the worm, so when the worm turns, so does the worm gear. When it turns 360°, it’s used for multiturn actuators, and when the worm has only turned a segment, it’s for quarter-turn actuators. Standard worm gears can be configured to fit almost any partial-turn CRANE PROCESS FLOW TECHNOLOGIES

or multi-turn valves, such as ball valves or butterfly valves. Worm gear operators create a mechanical advantage in torque, which reduces the amount of work or number of turns required to cycle a valve. Multi-turn actuators can be stopped either with torque switches or limit switches. TECHNICAL TRAINING

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COMPONENTS

Worm Shaft Gear

Valve Stem

Worm Gear

Motor

Worm

This is another view of the motor operation. The electric motor turns the worm shaft gear which rotates the worm. The worm then turns the worm gear and the worm gear rotates the valve stem. The limit switch shown is used to stop the motor based on the valve position, and it can also operate interlocks and position the indication lights. 372

Limit Switch Assembly

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Torque Switches

A worm gear-driven multi-turn actuator allows you to set the thrust on a gate or globe valve. That way, you can calibrate and select the amount of torque and thus the thrust the actuator will deliver to the valve. This is why multi-turn actuators are always the worm gear driven units, and a quarter-turn actuators are either worm gear or spur gear driven.

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COMPONENTS Drive Sleeve

Drive Sleeve Bearings Worm Gear

There are other components in the drive of an electric actuator. The drive sleeve has the Acme threads that the shaft will drive into. Then when it turns, so do the Acme threads of the stem, which pull it up or down or turn it if it’s a non-rising stem. The upper and lower bearings handle thrust from the stem as it is loaded in either direction. CRANE PROCESS FLOW TECHNOLOGIES

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COMPONENTS Limit Switch

This is an eye chart of the limit switch, which looks more complicated than it is. You do not need to know and memorize all of these locations, but one thing to note is the counting gears allows for a large number of rotations so that the switch can be set to trip at any valve stem location. Once the setpoint is reached, the rotor rotates 90 degrees to open some contacts and close others

be set at intermediate positions if something downstream or upstream needs to be controlled based on a middle position. There is a division within Crane Nuclear that refurbishes these and their mechanical components for nuclear power plants because they tend to wear over time and must be replaced. But there are a lot of moving parts involved.

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COMPONENTS Limit Switch Close Terminals

Open Terminals

Torque Switch Pinion

Open Adjusting Screw

Open Contact Limiter Plate Close Adjusting Screw Here you can see a torque switch arrangement, and the mechanism that drives it is rotary. The worm here has a rack that moves the pinion and then turns it radially. The torque switch is set to measure a specific amount of spring pack compression can be roughly converted CRANE PROCESS FLOW TECHNOLOGIES

to torque and thrust on the valve stem. Diagnostic testing is required to accurately set the amount of valve stem thrust or torque at a torque switch trip. If a motor keeps running against resistance and can’t operate, it could burn up, and this torque switch prevents that from happening.

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COMPONENTS Worm Gear

Valve Stem

Worm Gear Worm

Worm gears are constructed of a worm and a gear (sometimes called a worm wheel), with non-parallel, non-intersecting shafts oriented 90 degrees to each other. The worm is typically the driving component, with the worm’s thread advancing the teeth of the gear. This diagram shows a quarter segment of a worm for 90-degree operations. As we discussed, worm gears cannot be back driven. The worm can turn and drive 376

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the worm gear, but it stays at the same location, unlike spur gears which can drive freely both ways. When this is added to a triple offset butterfly valve, for example, and it is moved into the seat, torque is being applied to the seat. Therefore, when the handwheel is stopped, so too does the actuator, and it doesn’t back off. So, the triple offset seat torque is maintained and thus seats the seal.

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APPLICATIONS Electric Actuators are ideal when:

Air supply is not available Low ambient temperatures limit use of pneumatic actuators Valves are in a remote location or difficult to access

Electric actuators are ideal in several different applications. One would be when air supplies are not available. Another would be in low ambient temperatures that would limit the use of pneumatic actuators. A third application would be in instances where valves are in a remote location or are difficult to access. For example, most chemical process plants have pneumatic lines throughout the plant. So, it’s straightforward to run a Pneumatic actuator. CRANE PROCESS FLOW TECHNOLOGIES

Most of the actuators in a power plant are electric actuators. In refineries, electric actuators are commonly in place due to the use of gate and globe valves which are easier to automate with an electric actuator than pneumatically. Although pneumatic actuators are used in these applications on triple offset butterfly valves and metal seated ball valves since there are fewer moving parts in a Pneumatic actuation package, than there are with an electric actuation package.

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PROBLEMS & CAUSES Valve does not open or shut on demand Motor burn-up, broken gears, sheared key, motor overload tripped, broken stem or stem to disc connection.

Degraded stem or wrong stem thread lubrication.

Valve partially strokes but does not reach desired position Limit or torque switch set incorrectly, high stem to stem-nut friction, motor overload trips. There are several problems associated with electric actuators that can have various causes. If a valve does not open or shut on demand, it could be caused by motor burn-up. This can be caused when an actuator runs past its duty cycle, which could result in the motor overheating. Over time, the coating of the wires can start to break down, and if they break down enough, the electricity will jump from one wire to the next rather than going through the wires. This would cause the motor to burn up literally..

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Excessive stem to stem-nut friction

Bent stem Limit or torque switch set wrong resulting in excessive closing force applied.

Another potential problem is that the valve partially strokes but does not reach the desired position. This can happen if the limit or torque switch is set incorrectly, or the stem to stem-but friction could be too high. The stem to stem-nut friction is another problem caused by a degraded stem or the wrong thread lubrication. The Bent stem can occur if the actuator is sized incorrectly or if the limit or torque switch is set wrong resulting in an excessive closing force that can bend the shaft.

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PROBLEMS & CAUSES Broken stem/stemto-disc attachment

Motor overload tripping

Limit switches set wrong resulting Low actuator efficiency, torque in excessive loading into valve switch set to high, limit switch set backseat. wrong, broken/corroded rotor bars.

Sheared keys

Motor burn-up

Wrong key material, set screw loose, bad installation.

Torque switch set too high, excessive cycling, thermal overload failure, low supply voltage preventing motor from tripping torque switch.

A broken stem or stem-to-disc attachment can occur when the limit switch is set incorrectly, resulting in too much load in the back seat, which can lead to damage. Sheared keys are another problem that can occur if the key material is overloaded or the wrong key material is used. Motor overload tripping happens when there is low

actuator efficiency or if the torque switch is set too high. It can also occur if there are broken or corroded rotor bars. And finally, motorburn up, which we addressed earlier, is a problem that can occur when the torque switch is set too high or in cases of excessive cycling or thermal overload failure.

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TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

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13 Valve & Actuator Online Training Module

Valve Sizing

VALVE SIZING

LEARNING OBJECTIVES At the completion of this lesson, you will be able to: 1. Identify key parameters needed to properly select and size a valve. 2. Identify problems associated with incorrectly sizing valve. 3. Recognize the importance of Flow Coefficient for sizing. 4. Identify the formula for determining pressure drop. 5. Identify the formula for determining flow rate. 6. Define, “Choked Flow.”

Upon completing this course, you will be able to identify the key parameters needed to properly select and size a valve and recognize the importance of flow coefficient for sizing. We will also review the problems associated with incorrectly sizing a valve, outline the formulas for determining pressure drop and flow rate, and define “choked flow.” 382

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TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

VALVE SIZING

PARAMETERS Considerations when sizing a valve:

Pipe size Pipe material being used Valve shut-off pressure Service Media Temperature % of solids

Other valve considerations include the valve shut-off pressure and service media. If the media is very corrosive, the valve material must be aligned to that media. When it comes to selecting a valve, there are various parameters must be considered – certainly pipe size, but pipe material, as well. For example, if the pipe is made of carbon steel, then a carbon steel valve body can be used, though the body could be made up of a lesser material than the plug. So, in this case, the plug could be made of stainless steel to prevent the plug from corroding the body. CRANE PROCESS FLOW TECHNOLOGIES

Temperature is also critical. Higher temperatures would call for metal seated valves as opposed to soft seated, which have different temperature ranges that must be considered. The percent of solids present is another factor. The industrial diaphragm, for example, can only handle 20% of solids, so it would not be ideal for an application with a higher level of solids.

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VALVE SIZING

PARAMETERS Considered when sizing a valve:

Flow Rate at Maximum / Normal / Minimum Inlet Pressure at Maximum / Normal / Minimum Pressure drop at Maximum / Normal / Minimum Fluid Specific gravity Fluid Viscosity (if dissimilar to water)

Other considerations include the flow rate, inlet pressure, the pressure drop, fluid-specific gravity, and fluid viscosity.

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TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

VALVE SIZING

PARAMETERS Simplified Sizing for Liquids: Limitation: The pressure drop across the valve is less than 1/3 of the inlet pressure. If the pressure drop is greater then the “Complex Sizing” method must be used.

Two wo methods that can be used for sizing valves for liquids a simplified method and a complex one. When using the Simplified method, a limitation must be considered the pressure drop across the valve is less than 1/3 of the inlet pressure. So, if you have 300 lbs of inlet pressure, you would not want more than 100 lbs across the valve. If the pressure drop is more significant, then the complex sizing method must be used.

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385

VALVE SIZING

SIZING FORMULAS Simplified Valve Sizing Formulas for Liquid 𝑮𝑮 = 𝑸𝑸 ∆𝑷𝑷

𝑪𝑪𝑽𝑽 𝒐𝒐𝒐𝒐 𝑲𝑲𝑽𝑽

∆𝑷𝑷 = 𝑮𝑮(

𝑪𝑪𝑽𝑽

Flow Coefficient (Cv)

𝑸𝑸 )𝟐𝟐 𝒐𝒐𝒐𝒐 𝑲𝑲𝑽𝑽

𝑸𝑸 = 𝑪𝑪𝑽𝑽 𝒐𝒐𝒐𝒐 𝑲𝑲𝑽𝑽

Pressure Drop

∆𝑷𝑷 𝑮𝑮

Flow Rate

Here you can see the formulas used for the Simplified method. You can use these to calculate the flow coefficient, the pressure drop, and the flow rate to ensure the valve is fully energized. 386

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𝑪𝑽 = Valve Capacity Coefficient - ANSI

𝑲𝑽 = Valve Capacity Coefficient - EN 𝑸 = Flow in US Gallons/Minute or m3/hour ∆𝑷 = Differential Pressure in psi or Bar 𝑮 = Specific Gravity (Water = 1)

TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

VALVE SIZING

SIZING FORMULAS Solve for Flow Coefficient (Cv)

Flow rate = 248 gpm (56 m3/hr) Upstream Pressure = 96 psig (6.62 Bar) Downstream Pressure = 74 psig (5.1 Bar) Specific Gravity = .91 Cv = 1.16*Kv

𝑪𝑪𝑽𝑽 𝒐𝒐𝒐𝒐 𝑲𝑲𝑽𝑽

𝑮𝑮 = 𝑸𝑸 ∆𝑷𝑷

Cv = 50.4 Kv = 43.33

If you only have some of these values or parameters, then these formulas or iterations of them can be used to find the parameters you need. For example, here you can see how certain values can be plugged into the flow coefficient formula to find the outstanding values. CRANE PROCESS FLOW TECHNOLOGIES

𝑪𝑽 = Valve Capacity Coefficient - ANSI

𝑲𝑽 = Valve Capacity Coefficient - EN 𝑸 = Flow in US Gallons/Minute or m3/hour ∆𝑷 = Differential Pressure in psi or Bar

𝑮 = Specific Gravity (Water = 1)

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VALVE SIZING

SIZING FORMULAS Solve for Pressure Drop

Flow rate = 6650 gpm (1510 m3/hr) Cv = 1200 Kv = 1034.5 Specific Gravity = .88

∆𝑷𝑷 = 𝑮𝑮(

𝑪𝑪𝑽𝑽

𝑸𝑸 )𝟐𝟐 𝒐𝒐𝒐𝒐 𝑲𝑲𝑽𝑽

27 psi (1.87 Bar) The same applies to the Delta P formula. Algebraically, this formula is the same as the previous one, but just solving for Delta P instead of coefficient. So you’re able to use the values you have and plug them in where it makes sense to find the value you need, in this case, the Delta P. 388

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𝑪𝑽 = Valve Capacity Coefficient - ANSI

𝑲𝑽 = Valve Capacity Coefficient - EN 𝑸 = Flow in US Gallons/Minute or m3/hour ∆𝑷 = Differential Pressure in psi or Bar 𝑮 = Specific Gravity (Water = 1)

TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

VALVE SIZING

SIZING FORMULAS Solve for Flow Coefficient (Cv)

Flow rate = 248 gpm (56 m3/hr) Upstream Pressure = 96 psig (6.62 Bar) Downstream Pressure = 74 psig (5.1 Bar) Specific Gravity = .91 Cv = 1.16*Kv

∆𝑷𝑷 𝑮𝑮

𝑸𝑸 = 𝑪𝑪𝑽𝑽 𝒐𝒐𝒐𝒐 𝑲𝑲𝑽𝑽

5265 gpm (1192 m3/hr)

𝑪𝑽 = Valve Capacity Coefficient - ANSI

𝑲𝑽 = Valve Capacity Coefficient - EN 𝑸 = Flow in US Gallons/Minute or m3/hour

And again, for flow rate, you can plug in the parameters you have to find, in this case, the flow rate. CRANE PROCESS FLOW TECHNOLOGIES

∆𝑷 = Differential Pressure in psi or Bar

𝑮 = Specific Gravity (Water = 1)

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VALVE SIZING

DEFINITION D E FI NI TI ON

Choked Flow A pressure drop condition where maximum flow rate through a valve has been achieved for a given inlet pressure.

The definition of Choked Flow is a pressure drop condition where the maximum flow rate through a valve has been achieved for a given Inlet pressure. In other words, at some point, regardless of how much the Delta P is increased, there will not be any more flow. The formula would not work in that case because it is based on flow and the Delta P providing the flow coefficient. However, at some point, it won’t matter if the Delta P is increased because there will be a choked flow. Therefore, even if the maximum Delta p was reached, there won’t be any more flow through the valve. 390

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TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

VALVE SIZING

SIZING FORMULAS Simplified Valve Sizing Formulas for Gas Limitation: The pressure drop across the valve is less than 1/3 of the absolute inlet pressure. Choked flow is unlikely to exist at this pressure drop range. If the pressure drop is greater, then the “Complex Sizing” method must be used.

Return to this limitation we previously discussed, provided the pressure drop is less than a third of the absolute inlet pressure, choked flow is unlikely to exist, in which case the formulas we discussed can be used. So, if there is 100 PSI inlet pressure, less than a one-third drop would be 66.666 repeating or 67 PSI. As long as the Delta P is less than 33 or 34 PSI, the formulas can be used. CRANE PROCESS FLOW TECHNOLOGIES

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VALVE SIZING

SIZING FORMULAS Simplified Valve Sizing Formulas for Gases 𝑪𝑪𝑽𝑽 = 𝑲𝑲𝑽𝑽 = ∆𝑷𝑷 = ∆𝑷𝑷 =

𝑺𝑺𝒈𝒈 𝒒𝒒𝒒𝒉𝒉 𝑷𝑷𝟏𝟏 𝟓𝟓𝟓𝟓. 𝟔𝟔 ∆𝑷𝑷

Flow Coefficient (Cv)

𝑺𝑺𝒈𝒈 𝒒𝒒𝒒𝒉𝒉 𝑷𝑷𝟏𝟏 𝟐𝟐𝟐𝟐. 𝟒𝟒 ∆𝑷𝑷

𝑺𝑺𝒈𝒈 𝒒𝒒𝒒𝒉𝒉 ( )𝟐𝟐 𝑷𝑷𝟏𝟏 𝟓𝟓𝟓𝟓. 𝟔𝟔𝑪𝑪𝑽𝑽

𝑺𝑺𝒈𝒈 𝒒𝒒𝒒𝒉𝒉 ( )𝟐𝟐 𝑷𝑷𝟏𝟏 𝟐𝟐𝟐𝟐. 𝟒𝟒 𝑲𝑲𝑽𝑽

𝒒𝒒𝒒𝒉𝒉 = 𝟓𝟓𝟓𝟓. 𝟔𝟔 𝑪𝑪𝑽𝑽 𝑷𝑷𝟏𝟏

∆𝑷𝑷 𝑺𝑺𝒈𝒈

𝒒𝒒𝒒𝒉𝒉 = 𝟐𝟐𝟐𝟐. 𝟒𝟒 𝑲𝑲𝑽𝑽 𝑷𝑷𝟏𝟏

392

Pressure Drop

Flow Rate

∆𝑷𝑷 𝑺𝑺𝒈𝒈

The formulas we just reviewed were for liquids, but a different set of formulas are used when sizing valves for gases. This is because gas is an other matter with other properties, so different formulas must apply. We won’t go into detail on these, but one thing to note is that within these formulas, the Q’h - SCFH stands for a volumetric flow rate of standard cubic feet per hour.

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TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

VALVE SIZING

CHECK VALVES Swing Check

Opened and sustained in the open position by the force of velocity pressure, and closed by the force of gravity. Seating load and resultant tightness is dependent upon back pressure. Potential for water hammer Minimum flow or velocity is required to fully open the disc Now that you better understand the formulas, we’ll review sizing guidelines for various valve types, starting with Swing Check Valves. The seating load and resultant tightness are depended on back pressure. With this valve, there is a minimum flow or velocity required to fully open the disc and there is a formula for calculating that velocity.

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393

VALVE SIZING

CHECK VALVES Swing Check

The minimum velocity required to hold a swing check valve in the wide open and stable position is expressed by the formula:

Sizing swing check valves on this basis may often result in the use of valves that are smaller than the pipe in which they are used, necessitating the use of reducers for installation.

The minimum velocity required to hold a swing check valve in the wide open and stable position is the flow in feet per second which equals 60 times the specific cubic feet per pound volume. As long as that formula works, the swing check valve will be in the fully open position. However, swing checks sized on this basis often result in valves that are smaller than the pipeline. So even though the pipeline maybe 6 inches, to get the flow to the point that fully opens the valve, the valve may need to b sized at 4 inches. 394

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TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

VALVE SIZING

CHECK VALVES Tilt Disc Check

The minimum velocity required to hold a tilt disc check valve in the wide open and stable position is expressed by the formula:

Next, we’ll discuss check valves. To calculate the minimum velocity required to hold a tilt disc check valve, the same basic formula is used, but the factor is 80 instead of 60, making the minimum required velocity higher. CRANE PROCESS FLOW TECHNOLOGIES

TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

395

VALVE SIZING

CHECK VALVES Stop Check

Stop Check Valves are as essential to safe operation of a boiler plant as safety valves or other safety devices attached to the boiler. When more than one boiler is connected to the main steam header, a stop check valve should be installed in the pipeline between each boiler and the header.

The stop check valve combines two: the globe valve and the lift check valve. Stop checks are essential to the safe operation of a boiler plant and operate as safety valves in that application. When more than one boiler is connected to the main steam header, a stop check valve should be installed in the pipeline between each boiler and the header. The stop check 396

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Valve designed for steam application that operate between 100 psi (9 bar) and 375 psi (26 bar). The Stop Check feature of this valve requires a minimum of 50 psi (3.5 bar) pressure differential between the piping system and the boiler to operate correctly.

valve can control how much flow goes out of the header and stops the flow from feeding back into the boilers. It is designed for steam applications that operate between 100 PSI and 375 PSI, and the stop check feature requires a minimum PSI pressure differential between the piping system and the boiler to operate correctly.

TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

VALVE SIZING

CHECK VALVES Stop / Lift Check Technical Data Bolted Bonnet Stop Check Valve Graphic representation of flow data determined by test

For details please see “TECHNICAL DATASHEET CRANE® - Cast Steel Valves

When it comes to sizing a stop check valve, you must use this technical data sheet for Crane cast steel valves to determine the right size. Just because you may have a 6-inch pipeline does not mean that a 6-inch stop check will work with it. Instead, this technical data sheet will walk you through the required sizing steps. CRANE PROCESS FLOW TECHNOLOGIES

TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

397

VALVE SIZING

ENGINEERED CHECK VALVES Engineered Check uses a sizing program to optimize the spring assist to the customer’s applications. The opportunity to use the sizing program as a selling tool should not missed or under-estimated. By correctly sizing the valve we can benefit the customer by:

Reduce wear / Improved valve life Minimise reverse velocity (less water hammer) Protect the pumping equipment

Engineered check valves use a sizing program to optimize the spring assist based on the customer’s specific application parameters. The opportunity to use this program as a selling tool should not be overlooked, as there are several benefits to the customer, including reduced wear, minimized reverse velocity, equipment protection, reduced pressure loss, and the opportunity to educate the customer on our check valves.

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Reduce pressure loss / Savings on running costs Educate the customer about our Check Valves.

Sizing the engineered check valve correctly will save the customer a lot of headaches and money, especially compared to competing manufacturers’ valves. Ultimately, our Noz-Chek and Duo-Chek engineered check valves are not considered “engineered” simply because we engineer them up front, which is also true, but rather because we’re able to fine-tune them to the customer’s requirements.

TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

VALVE SIZING

ENGINEERED CHECK VALVES Customer should supply the details as above or on similar style data sheet.

Using this program, the customer can supply us with all the details about their application, such as pressure drop, line size, whether it’s a straight pipe or has a bend, what the conditions are, etc. Using that information, the program completes the calculations and specifies what the valve size should be, as well as the spring load that optimizes it for the customer’s application.

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399

VALVE SIZING

CHECK VALVES Swing Check Valves

Relatively long response times under dynamic conditions

Swing check valves have relatively long response times under dynamic loads and high reverse velocities resulting in slamming. Therefore, on this chart, the flatter the curve is, the less potential there is for a water hammer. So between Noz-Chek and Duo-Chek, 400

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High reverse velocities resulting in slam effect and unwanted pressure surges

we have the suitable valve types available to us to supply the customer with the correct check valve for the intended application; it’s all just a matter of understanding the customer’s requirements.

TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

VALVE SIZING

CHECK VALVES Spring assisted Dual Plate check valves (Duo-Chek®)

Design offering slimmer plates with less inertia than a single thicker disc (as in the Swing check type)

The Duo-Chek, has slimmer plates and less inertia than a single thicker disc, as compared to the swing check valve type. In addition, the spring per-loading provides additional closing force at all angles, and the springs CRANE PROCESS FLOW TECHNOLOGIES

Spring pre-loading provides additional closing force at all angles Enhanced response time as well as more reactive to changes in flow conditions.

can be fine-tuned based on the customer’s needs. The enhanced response time and reaction to changes in flow conditions provide better performance than a swing check valve.

TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

401

VALVE SIZING

CHECK VALVES Nozzle check valves (Noz-Chek® & Compac-Noz®)

As flow decelerates, the spring overcomes decaying fluid force on the disc and triggers the valve to close Low disc mass combined with spring loading and

The Noz-Chek and Compac-Noz valves are at the premium end of the spectrum. As the flow decelerates, the spring overcomes decaying fluid force on the disc, and the venturi pulls the disc out 402

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short displacement ensures rapid self-dampening response. Fastest response time, slam free and with minimal reverse velocity.

and triggers the valve to close. The spring assist, and the force happens almost instantaneously, so there’s minimal potential for deceleration and water hammer.

TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

VALVE SIZING

CHECK VALVES Check valve selection

NOZ-CHEK with strong spring NOZ-CHEK with standard springs COMPAC-NOZ Check

DUO-CHEK II with strong springs DUO-CHEK II with standard springs Tilting disc check Conventional Swing Check

Identify key parameters needed to properly select and size an actuator.

From this chart, you can see that Crane offers a full range of check valves. From the tilting disc with its enhanced non-slam performance to the Duo-Chek with tuned springs, the Compac-Noz and Noz-Chek as CRANE PROCESS FLOW TECHNOLOGIES

standard, and the Noz-Chek with unique springs, there’s something to satisfy the full range of applications, no matter the criticality of service or the nature of the operation. TECHNICAL TRAINING

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14 Valve & Actuator Online Training Module

Actuator Sizing

ACTUATOR SIZING

LEARNING OBJECTIVES At the completion of this lesson, you will be able to: 1. Identify key parameters needed to properly select and size an actuator. 2. Identify problems associated with incorrectly sizing an actuator.

Upon completing this course, you will understand the key parameters needed to select and size an actuator properly, and you will be able to identify problems associated with incorrectly sizing an actuator. 406

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TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

ACTUATOR SIZING

CONSIDERATIONS Considerations when sizing an actuator:

Load requirements for the valve (torque and thrust) Available power supply Speed of operation needed Frequency of operation How valve is being used

When sizing an actuator, there are several factors that must be considered. The load requirements of the valve, as well as the torque and thrust, are listed here first. Also, the available power supply and whether pneumatic pressure is available or electric must be considered. These are the two types of power that Crane primarily uses, but there is a third type called hydraulic power that other manufacturers rarely use in specific cases. Speed of operation is the next consideration. If the actuator needs to go very fast, then a pneumatic actuator would be best, as the speed of electric actuators can’t really be increased, so they typically have a longer cycle time. Finally, frequency of operation, or how often it will be cycled, is another factor that must be considered. This is where the duty cycle comes into play. For example, with an electric actuator that will often be modulating, a motor with a duty cycle of 25% or 50% wouldn’t be used. Instead, one with a 100% duty cycle would be selected, meaning the motor can be continuously operated. Whereas if it’s going to only be used periodically, a motor with a 100% duty cycle would be unnecessary. Operators must also take into account how the valve is being used. For instance, whether as an on-off valve or for modulating and what media is being processed. CRANE PROCESS FLOW TECHNOLOGIES

Double acting or fail-safe requirement Operating environment Manual override requirement Weight or size considerations

Double acting or Fail-Safe requirements are another essential aspects. In other words, is a spring return actuator needed or a double-acting actuator? A critically important consideration is the operating environment. Suppose the actuator package is going to be next to a furnace that’s not insulated. In that case, it’s important to ensure that the seals in the selected actuator can handle that higher temperature. Or, if the actuator is going to be in an extremely cold location, then a seal that stays flexible at low temperatures would be needed. Manual override requirements must also be considered. Some electric actuators have a hand wheel as a standard inclusion that acts as the manual override, while it has to be specified on others. Pneumatic actuators, on the other hand, typically have more of a gear override that fits on top of the actuator that must be engaged or a sandwich worm gear operator. Typically, the sandwich gear overrides are limited in torque carrying capabilities, which must be considered ahead of time. And finally, weight or size considerations have also to be factored in. Some valves would require a very large and heavy actuator, so the end-user would have to ensure that they have the accommodations to support that valve.

TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

407

ACTUATOR SIZING

CONSIDERATIONS Basic Actuator Sizing

Pneumatic Double Acting (DA) Pneumatic Spring Return (SR) Fail-Open Fail-Closed

These are the primary actuator sizing considerations: Pneumatic double-acting, Pneumatic spring return, fail open and closed. 408

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TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

ACTUATOR SIZING

CONSIDERATIONS Valve Torque Characteristics

Ball Valve

Butterfly Valve

Various torque characteristics also must be considered when selecting the size of an actuator. Here you can see the primary torque curves for some of the more popular rotary valves. As you can see, the ball valve starts with a high brake torque and low run, with a seating torque of about 70%. With the butterfly valve, the closing and opening torque when in the seat is high but there is no seat in the open position, unlike a ball valve. So, the torque drops off and stays off. CRANE PROCESS FLOW TECHNOLOGIES

Plug Valve

With the sleeved plug valve, the torque is high and drops down but not near as far as the ball or butterfly valve. It then rises a little for the close. When sizing the actuator, it’s essential to ensure that the specific pneumatic start and pneumatic end and the spring start and spring ends are all greater than these numbers as the valve opens and closes.

TECHNICAL TRAINING

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409

ACTUATOR SIZING

CONSIDERATIONS Double Acting Actuator Torque Profile

The rack and pinion actuator has a constant torque curve. 410

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TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

ACTUATOR SIZING

CONSIDERATIONS Double Acting Actuator Torque Profile Scotch Yoke

Torque

Double Acting

Closed

Open

Travel

In a scotch yoke actuator, the maximum torque is at the ends of the stroke. CRANE PROCESS FLOW TECHNOLOGIES

TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

411

ACTUATOR SIZING

DOUBLE ACTING SIZING Double Acting Sizing 1. Determine max valve torque based on seat material, pressure drop, etc. Hydrodynamic torque must be included for butterfly valves. 2. Apply the application safety factor. 3. Apply the actuator manufacturer safety factor. 4. Select an actuator (at the appropriate supply pressure) whose torque exceeds the max valve torque times the safety factors. When sizing a double-acting actuator, you must first determine the maximum valve torque with the seat material and pressure drop. Then, specifically for butterfly valves, the hydrodynamic torque must be included. Also, the application safety factor provided by the manufacturer must be applied, and so does the actuator safety 412

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factor that the manufacturer of the actuator provides. Once complete, an actuator can be selected at the appropriate supply pressure, considering where the torque exceeds the maximum valve torque times the safety factors.

TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

ACTUATOR SIZING

DOUBLE ACTING SIZING Typical Application Safety Factors (Sleeve Plug) Normal Service Chlorine Service Dry Service Vacuum Service Slurry / Abrasion Idle Time

F = 1.0 F = 1.5 F = 1.5 F = 1.5 F = 2.0 F=*

* Variable from 1.0 to 1.5 depending on time between cycles.

Using a sleeved plug valve as an example, let’s review what the application safety factors would look like.

to dry service and vacuum service, as well. At the same time, slurry or abrasion service has a safety factor of 2.

In standard service, the safety factor would be 1, but in Chlorine Service, the safety factor is 1.5. This is because the torque standard of chlorine service is one and a half times that torque. This applies

Idle time refers to the time the valve will be idle between cycles. That safety factor would vary from 1 to 1.5 depending on the time between cycles.

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TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

413

ACTUATOR SIZING

DOUBLE ACTING SIZING Actuator

Here you can see the torque curves of the ball valve, butterfly valve, and plug valve, and as you can see, the safety factor would need to be above them. 414

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TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

ACTUATOR SIZING

SPRING RETURN SIZING

Fail-Closed: Air to open, spring to close Fail-Open: Air to close, spring to open

As for Spring Return sizing, because some of the pneumatic pressure is being used and the full torque is not available, the air start/air end and spring start/ spring end is going to be variable. So when sizing, it’s essential to review the chart to ensure that all four points are above the opening/closing torque and the run torque of the particular valve. CRANE PROCESS FLOW TECHNOLOGIES

TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

415

ACTUATOR SIZING

SPRING RETURN SIZING Scotch-Yoke Type

Torque

Single Acting

Closed

Travel

The scotch yoke again has a characteristic curve. It’s slightly different here than in the Double Acting Actuator torque profile, but the same principle applies. 416

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TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

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ACTUATOR SIZING

SPRING RETURN SIZING 1. Identify valve start & ending torques 2. Torque is not constant through out the stroke 3. Consider four primary torque positions a. Air Start b. Air End c. Spring Start d. Spring End 4. Actuator ctuator selected must be able to overcome both valve starting and ending torques on both air and spring ranges and torque in any intermediate position

You’ll Y also need to consider the four primary torque positions: air start, air end, spring start, and spring end.

When sizing a spring return actuator, you must first identify the valve start and end torques. Because of the high seating torque at the end of the closing stroke, there is an advantage to using a reduced spring set, which results in a higher end of the stroke for the actuators’ air torque stroke. CRANE PROCESS FLOW TECHNOLOGIES

The selected actuator must be able to overcome both the valve starting and ending torques on both air and spring ranges and torque in any intermediate position. |

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ACTUATOR SIZING

SPRING RETURN SIZING Single Acting Torque

As stated, it will have an air start and air end. And a spring start and spring end.

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TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

ACTUATOR SIZING

SPRING RETURN SIZING (in-lb)

This is an example of what the spring return sizing charts would look like for the Xomox XRP, which is identical to the REVO. This page and the following show the sizing in inch-pounds, and if you look to the left, you can see that the sizing provided is for the XS2, 6, 12, 25. CRANE PROCESS FLOW TECHNOLOGIES

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ACTUATOR SIZING

SPRING RETURN SIZING (Nm)

Depending on the air pressure available, you can also see what the pneumatic start and pneumatic end would be based on two springs.

Each chart shows the number of springs in the end cap per side, so two on one side and two on the other. So, in this first row, can to see what the spring start and spring end would be with two springs in an XS50. 420

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TECHNICAL TRAINING

VALVE & ACTUATOR OVERVIEW

ACTUATOR SIZING

KROMBACH MS BALL SIZING Calculating valve torque Base Valve Torque Media (Service) Factors Cycle Frequency Factors (Default to 1.3) Valve Operating Torque Factors Break = 100% Run

= 65%

Seat

= 92%

Valve Torque 2.6 Media Service Factor 1.3 Cycle frequency Factor 203 ft/lbs 203

100% Break

132

65% Run

187

92% Seat

(275 Nm) (179 Nm) (253 Nm)

This is an example of calculating the valve torque on a Krombach metal seated ball valve. You can see that the media service factor is 2.6, and the cycle frequency is 1.3. Based on that, the torque at the Delta P in foot-pounds is 20 bar or 290 PSI. Therefore the brake torque is 203-foot-pounds. The trick is that the numbers used in this calculation are foot-pounds and the CRANE PROCESS FLOW TECHNOLOGIES

numbers on the first set of charts we just reviewed are in inch-pounds, so the factors would need to be converted. To do so, you would need to multiply the footpound value by 12. Using the newton meters values, you can see those to the right of the foot-pound values. TECHNICAL TRAINING

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ACTUATOR SIZING

GATE & GLOBE SIZING Thrust (lbs) = [StA]*[LP] + [PL] + [SA]*[VF]*[DP] StA = Stem cross sectional Area LP = Line Pressure PL = Packing Load (estimated at 2000 lbs per inch of stem diameter for graphite packing) SA = Seat Area DP = Differential Pressure the valve is opening/closing against VF = VALVE FACTOR. 0.25 - Parallel seat 0.30 - Gate valve 1.10 - Globe valve These formulas get you a baseline thrust value with no safety factor. You’ll need to add an appropriate safety factor for your service.

When it comes to determining the thrust, there is a formula that can be used. That formula is STA, which is the stem crosssectional area, times the line pressure, plus the packing load, which is estimated at 2,000 pounds per square inch of stem diameter for graphite packing, plus the 422

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seat area times the valve factor times the differential pressure. This formula gives you the baseline thrust value with no safety factor, so the actuator safety factor must be applied is typically around 25%.

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VALVE & ACTUATOR OVERVIEW

ACTUATOR SIZING

GATE & GLOBE SIZING Electric Actuator Sizing 1. Electric actuator output capability is constant with position 2. Determine max valve torque/thrust based on seat material, pressure drop, etc. 3. Apply the application safety factor 4. Apply the actuator manufacturer safety factor 5. Select an actuator whose rated torque/thrust capability exceeds the max valve torque times the safety factors

the actuator can provide the required amount, taking into account the safety factor for the application and the actuator manufacturer. The actuator selected needed a rated torque or thrust capability that exceeds the maximum valve torque times the safety factors.

Electric actuator sizing is pretty straightforward. First, you determine the torque or thrust needed based on the factors we just went over. To determine an electric actuator sizing, would use that formula to calculate the torque or thrust needed to confirm that

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ACTUATOR SIZING

PROBLEMS & CAUSES Valve partially strokes but doesn’t reach desired position Actuator not sized to handle all operational loads.

Bent or broken stem or stem to disc attachment Actuator oversized.

Seat leakage Actuator undersized not producing sufficient torque or thrust to fully seat the valve.

Motor overload tripping Actuator not sized to handle all operational loads.

Motor burn-up Actuator not sized to handle all operational loads.

Several problems can result if an actuator is not sized correctly. First, if the valve partially strokes, but does not reach the desired position, then the actuator is not sized to handle all the operational loads. Seat leakage is another problem that is caused by an undersized actuator that doesn’t produce enough torque or thrust to fully seat the valve. Oversized actuators cause broken or ben stems. To avoid this, especially on electric actuators. The torque switch needs to be set so that it doesn’t exceed the trust capability of the stem. Another problem that can occur is motor overload

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Control valve instability/ lack of control Actuator design not adequate for specific valve and control application. tripping, where it’s not operating, and the duty cycle factor is not correct. And finally, control valve instability, or lack of control. When you are controlling a valve, you must be able to stop it anywhere in the curve, and there must be enough torque for the valve to brake. So, for example, if you are sizing a control valve that has torque in the middle, you must ensure that the actuator torque is more significant than that valve torque, otherwise, you won’t be able to control it. That’s why the actuator design must be indeed adequate for the specific valve and control application.

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ACTUATOR SIZING

CONSIDERATIONS Actuator Selection and Sizing Considerations

What are the load requirements for the valve regarding torque and thrust? What power supply do you have available? Is the speed of operation a consideration? What is the frequency of operation? How is the valve being used? Does the valve require doubleacting action or is it required to fail in a specific position? What is the operating environment? Is a manual override required? Are there dimensional/weight considerations?

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