Fluid Handling International May/June 2016

HELPING TO KEEP YOUR BUSINESS FLOWING

Issue 3 Volume 4

MAY/JUNE 2016

The venerable veteran Modernising a historical water pump station

A combined effort

Companies banded together to save a city’s wastewater system

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COMMENT & CONTENTS

Contents 2

Latest news

8

Product showcase

9

29

The venerable veteran A UK pump station has been modernised without sacrificing its traditional charm

Fast action for safety With double block and bleed installations, the safety of the valve system can be dependent on the valves’ closing speed

31

The good ol’ boy A Finnish paper mill needed its vacuum pump repaired after 45 years, but the old workhorse’s good overall condition came as a surprise

Woodcote Media Ltd Marshall House 124 Middleton Road, Morden, Surrey SM4 6RW, UK www.fluidhandlingmag.com

10 Disasters waiting to happen

The latest silo protection technology provides much more than a safety system to prevent over-filling and over-pressurisation

32

Ultrasonic on the rise Custody transfer applications drive the growth in the ultrasonic flowmeter market

12

The many colours of the butterfly Butterfly valves are increasing their popularity in modern piping solutions, and for a good reason

34

A novel approach A new kind of ultrasonic flowmeter enables accurate measurement in low flow applications

MANAGING DIRECTOR Peter Patterson Tel: +44(0)20 8648 7082 peter@woodcotemedia.com

14

Dampening the blow High-performance damper drives are necessary for ensuring operational safety in several fields

37

Event preview: ILTA 2016

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19

Researching safety

22

The saint of sewage A new chopper pump has proven a godsend at a Californian rescue mission struggling with a broken-down sewage disposal system

24

The Yin and Yang With the right choice of vacuum pump, significant savings in cost of ownership and maintenance can be realised across industries

May/June 2016 ISSUE 3 • VOLUME 4

EDITOR Ilari Kauppila Tel: +44 (0)20 8687 4146 ilari@woodcotemedia.com DEPUTY EDITOR Liz Gyekye Tel: +44 (0)20 8687 4183 liz@woodcotemedia.com ADVERTISING SALES MANAGER Georgina Barry Tel: +44 (0)208 6487 092 georgina@fluidhandlingmag.com PRODUCTION Alison Balmer Tel: +44 (0)1673 876143 alisonbalmer@btconnect.com SUBSCRIPTION RATES A one-year, 6-issue subscription costs £150 (approximately $240/€185 depending on daily exchange rates). Individual back issues can be purchased at a cost of £30 each Contact: Lisa Lee Tel: +44 (0)20 8687 4160 Fax: +44 (0)20 8687 4130 marketing@woodcotemedia.com

Join Fluid Handling International on Linkedin to discuss important issues Follow us on Twitter: @FluidHandIntl No part of this publication may be reproduced or stored in any form by any mechanical, electronic, photocopying, recording or other means without the prior written consent of the publisher. Whilst the information and articles in Fluid Handling are published in good faith and every effort is made to check accuracy, readers should verify facts and statements direct with official sources before acting on them as the publisher can accept no responsibility in this respect. Any opinions expressed in this magazine should not be construed as those of the publisher.

26

Resolving water hammer through transient monitoring equipment

A combined effort A group of companies rose to the challenge of designing and supplying a new wastewater station in just three weeks

40 Keep it in the tank

Appropriate leak protection in chemical applications is essential for preventing catastrophic spills 43

The high-pitched snitch

45

Steam vs thermal fluid Thermal fluids are challenging good old steam’s supreme position in heat transfer applications

47

HELPING TO KEEP YOUR BUSINESS FLOWING

Issue 3 Volume 4

MAY/JUNE 2016

From the vacuum they came An overview of vacuumtreated valves and their significance

The venerable veteran Modernising a historical water pump station

A combined effort

Companies banded together to save a city’s wastewater system FH Front cover May June.indd 1

48 Events

A view from a modern wastewater plant. ©roibu. Picture from bigstockphoto.com

06/05/2016 16:02

Comment Dear reader, Water is important. Without it none of us would be here, and clean water is the foundation stone of any civilisation. But you don’t need me to tell you this, you already know it. The only reason I’m stating it is to introduce this May/June issue of Fluid Handling International and its focus on water and wastewater.

The current worldwide situation seems to open at least some doors for water operators. Long-term droughts in certain parts of the world, such as California, will increase the demand for new and innovative solutions to make the most out of the water available. But there is one certain region what could be more promising than others.

The Middle East is, despite the area’s unfortunate political and social upheaval, growing at a fantastic rate. This growth is increasing the pressure on the area’s governments to secure and safeguard the basic utilities of life necessary for their increasing populations. And this, naturally, includes water. Already scarce in the arid area, water recycling could be the answer to many a problem.

To this end, several projects are underway all over the Middle East to provide the invaluable wastewater services. And these projects are massive. To name just a couple, Ashgal is constructing the $2.2 billion (€1.9bn) Doha North Sewage Treatment Works in Qatar, while Haya Water is building the Muscat Sewerage Redevelopment project in the Sultanate of Oman’s capital of Muscat.

Investment in this project has so far reached £3.23 billion, but with its completion estimated for 2020 earliest, there’s still sure to be possibilities for water treatment equipment manufacturers.

But it’s not just about the dry regions of the world that need water, and the articles we have for you in this issue reflect that fact. On page 22 you can read how a chopper pump helped a struggling rescue mission’s wastewater problems, and on page 29 we bring you a story of refurbishing a UK pump station while still maintaining its old-timey charm.

But water’s not all we have, and between these covers you’ll also find stories on butterfly valves, ultrasonic flowmeters, and leak detection solutions. Without further ado, I wish you an enjoyable read!

Best wishes,

Ilari ISSN 2057-2808 1

VALVE NEWS

Emerson enhances digital valve controller software to include Profibus protocol

Rotork acquires gearbox manufacturer Mastergear

Emerson has enhanced the software for its Fisher Fieldvue DVC6200 series of digital valve controllers, which are now available with PLCs and Profibus communications as the dominant protocol.

The Fieldvue DVC6200p digital valve controller with device type manager (DTM) software supports control valve start-up, commissioning, and diagnostic activities.

It has also been tested and integrated for use with multiple field device tool (FDT) host systems.

Industries including food and beverage, water and wastewater, pharmaceutical, pulp and paper, and metals and mining will find value in the Fieldvue DVC6200p DTM instrument’s intuitive interface, says Emerson.

Available in a variety of materials, including stainless steel, the device comes with mounting kits to accommodate different actuators and the kits can also be reused in upgrades to existing Fieldvue instruments.

For control valves located in critical or hazardous areas, the Fieldvue DVC6200p may be remotely mounted to enhance its performance in harsh process conditions such as high-heat or vibration.

Utilising human-centred design concepts, the Fieldvue DVC6200p DTM has several features that simplify control valve set-up and monitoring.

Its intuitive set-up, auto-calibration, and simple tuning features save time during commissioning, and with the failsafe option, users can set the instrument to hold its last value or position Fieldvue DVC6200p to actuator fail, based on control valve process needs. digital By incorporating control logic, module assignment, valve controller and linkage-less, non-contact sensor technology, the Fieldvue DVC6200p digital valve controllers and DTM are easy to install, provide “plug and play” capabilities, and perform reliably even in harsh environments. z

Rotork, the Bath, UK-based valve maker has acquired gearbox manufacturer Mastergear at a price of $25 million (€21.9m).

Mastergear, a producer of manual and motorised valve gearboxes for the oil and gas, water, chemicals, and general industrial markets, was previously owned by Regal Beloit Corp.

The company, with an annual turnover of $22 million and its operational centre in the US and Italy, will become part of Rotork’s gears division.

“Mastergear has a well-regarded product portfolio that will enable Rotork to offer its customers a more comprehensive range of products and services,” said Peter France, CEO at Rotork.

“The acquisition is in line with our strategy and strengthens our presence in the flow control sector, including the water distribution and treatment market.”

In a trading update, Rotork has revealed that order intake and revenue increased 2.5% and 0.7% respectively in the first quarter, boosted by favourable exchange rates and contributions from recent acquisitions. z

Expert: Pipeline collapse proves urgent need for air valves The catastrophic collapse of a pipeline at a $10 million (€8.8m) project in Central America is clear proof that current procurement of air valves needs to be urgently reviewed, according to IVL Flow Control.

Craig Stanners, director of IVL Flow Control, part of Ham Baker Group, said: “This latest incident was actually caused by not having any air valves at all, which was a disastrous oversight by the consultant.

“In an increasing number of cases it is not the end-user or the contractor at fault. It’s a lack of understanding from consultants who don’t seem to understand that when you are putting water into a pipeline or draining out due to a burst, air must be let in – and let out,” Stanners said.

According to Stanners, the vacuum created by negative pressure in a system, caused by no air valves or the wrong type of air valves, is enough not just to destroy plastic pipelines, but tough metallic materials too.

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He said that the “ludicrous recommendation” by the consultants for the unfortunate Central American project to make do without air valves probably initially “saved” around £7,000 (€8,906), to which he commented: “What an oversight.”

Unfit products “In the UK, there is a plague of cheap plastic air valves in the ground. These valves are a single, air-out only function, costing around £70. Instead, two-way valves (for air-in and air-out) should be installed, but because they’re closer to £170, procurement departments or consultants think they’re doing a great job with savings,” Stanners lamented.

“Perhaps they could explain then why in the US alone there is now $346 billion worth of failing assets in the ground. I don’t call that much of a saving.”

Stanners said he was horrified to be

quoting on one recent project when the asset manager had to admit that although the municipal company knew they had air valves, they did not know exactly where – only that the contractor had used “a load” left over from a previous job.

Subsequent failures with poor tap pressures was already producing numerous complaints from consumers, dragging down the concerned water company’s reputation.

“In an age where anyone could use Google to get an idea of topography, it seems unforgiveable that some consultants aren’t even specifying air valves to be installed every 500m on just a straight length of pipe,” Stanners concluded.

“And it’s madness too for those who do specify to then cut corners with cheap or unsuitable air valves. It is time to install the right, long-lasting product and stop adding to the stockpile of failed assets buried in the ground.” z

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016

VALVE NEWS

AVK releases knife gate valves with new linear electrical actuator

New ball valves for tough operating conditions

Valve manufacturer AVK, which services the North and South American markets, has recently released its knife gate valve series 702/73 with a new linear electrical actuator.

The valves are available in DN 50-300 with the same actuator type for the complete range.

The linear electrical actuator is a robust product used in many different industrial applications, which makes it appropriate for use in the wastewater segment for valve actuation.

It is self-locking when not in operation, features accurate positioning, and is an eco-friendly solution due to its 24V motor.

The knife gate valves are available with WCU Basic for analogue control of 4-20mA feed-back signals, WCU Bus for integrated BUS-communication module (Profibus), WCU UPS external battery back-up unit, and a programming unit for programming and copying of parameters.

The WCU Basic or the WCU Bus are needed in order for the knife gate valve to work, while the WCU UPS is optional if power failures are frequent.

The control unit is easy to install and programme, and power and control cables are connected to the actuator by means of plugs and are easy to replace.

The unit can be integrated into existing monitoring and control systems.

If a power failure should occur, and a WCU UPS battery back-up is not connected, it is possible to open and close the valve manually. z

Industrial valves specialist AS-Schneider has expanded its product range to the KB and KC Ball Valve Series with a bore size of 14 and 20mm.

The ball valves are especially suitable for the most demanding applications in the oil and gas industry and process industry, the company says.

The series already meets all current tightness and safety requirements in the standard version.

The two new ball valve series feature robust and well-thought-out construction, with a floating ball that allows a low operation torque even under difficult operating conditions.

To eliminate leakage in the event of temperature fluctuations or stress losses, the valves are equipped with a metallic body to end connector sealing.

They withstand a pressure of up to 420 bar and temperatures from -30 to 232°C, and the available body materials include carbon steel and 316 stainless steel.

Upon request, AS-Schneider

also provides special alloys like Alloy 400 and Alloy C-276.

High quality PEEK or Reinforced PTFE are used for the ball seat.

The anti-blowout stem is discharged anti-statically against the body and thus ensures high explosion and fire protection.

The stem seal, made of PTFE, is designed for low wear and long-term safe operation even in fugitive emission applications.

The valves are tested and certified according to ISO 15848 and are also Fire Safe tested and certified according to ISO 10497 / API 607.

The ball valve series with bore sizes of 14mm and 20mm are available with a variety of types and options, the choices including those for use with demanding process media such as oxygen or for low-temperature service.

An extended body, threaded for panel mounting, or a lockable handle which prevents unauthorised operation of the valve are further options. z

The new KB and KC ball valve series by AS-Schneider withstand high pressures and a great temperature range

Weir Oil & Gas unveils next-generation valve and seat technology Fort Worth, Texas-based Weir Oil & Gas has unveiled the new SPM 2.0 valve and seat for well stimulation pumps used in shale plays globally.

The reveal comes following two years of research and more than $1 million (€874,000) invested in advanced engineering and comprehensive testing.

Designed and manufactured from premium-grade materials and processes, the SPM 2.0 encompasses a one-piece, patents-pending design, proprietary polymers, and innovative geometry.

“The real goal of creating new valve and seat technologies that perform better and longer is to minimise total cost

of ownership,” said Chris Buckley, VP of pressure pumping at Weir Oil & Gas. “The new SPM 2.0 is not just another valve and seat. It is a vital component in helping our customers decrease costs in an economically challenging and continuously evolving industry.”

Validated through extensive testing to perform two times longer, the SPM 2.0 valve and seat can help oil and gas companies maximise their return on investment by delivering longer operational service life and increasing pumping hours.

It features bonded valves and improved performance, increased resistance to abrasion, extrusion and flow erosion,

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016

and it eliminates moulding movement, leakage and separation from valve.

The SPM 2.0 valve & seat is designed and manufactured in-house to sustain rigid quality control standards. z

Weir’s new SPM 2.0 valve and seat can help lower total cost of ownership at oil sites

3

PUMP NEWS

Graco releases new ToughTek portable stucco pump Graco, a manufacturer of fluid handling equipment, has released the ToughTek portable stucco pump for stucco and exterior insulation and finish system (EIFS) materials.

The pump is the newest addition to Graco’s ToughTek product line of compact and portable pumps that use piston pump technology to deliver abrasive materials with a smooth, steady flow.

“These new ToughTek stucco pumps can handle the stucco and EIFS materials required for the job, allowing contractors to use one pump from start to finish,” said John Lihwa, Graco product manager.

For EIFS applications, the ToughTek S340e Stucco Pump handles air/ water-resistive barrier materials, EIFS

basecoats and finish coats.

For stucco applications, the unit handles scratch coats, brown coats, and finish coats.

The ToughTek stucco pump’s compact design and small footprint make it easy to spray in tight areas, and it is easy to set up, easy to use, and requires minimal maintenance, according to Graco.

The pump features variable speed controls to allow contractors to dial in the exact flow rate needed, from low to high-volume output.

Utilising proprietary Graco technologies, the piston pumps stand up to abrasive stucco and EIFS materials to minimise maintenance downtime and reduce wear part expenses.

The ToughTek stucco pump handles stucco and EIFS materials from start to finish

The pump plugs into a standard 120V wall outlet or may be used with a 5.5kW generator.

It is easily lifted by two people and comes with a 20-gallon hopper. z

Sulzer releases new design of submersible recirculation pump Sulzer has introduced a new efficient submersible recirculation pump type ABS XRCP 800 PA with a completely new design.

The new pump series is developed for the pumping and recirculation of activated sludge in wastewater treatment plants during the nitrification and denitrification process, as well as for the pumping of storm, surface, and river water.

It complements the submersible recirculation pump series ABS RCP. The new XRCP 800 PA pump series offers an economical and reliable option for wastewater treatment applications.

The low energy consumption of the pump brings savings in total life-cycle costs and reduces the environmental footprint, and it is designed as a compact, water-pressure-

tight unit, including the propeller and bracket.

The well-proven automatic coupling system uses a single guide rail and guarantees a quick and economical installation.

The XRCP is available in two standard material versions, cast iron and stainless steel, and its maximum medium temperature for continuous operation is 40°C. The XRCP 800 PA series pumps are equipped with a submersible premium efficiency IE3 squirrel cage and three-phase, four-pole, 50Hz (60Hz) motors with a power range up to 22kW in the insulation class of F (155°C).

Sulzer’s present submersible recirculation pump series ABS RCP will be maintained in parallel with the new XRCP series for the time being. z

PSG adds redesigned models to its peristaltic hose pump line for mining industry PSG, a Dover company and a pumps and flow control solutions manufacturer, has designed new models of its Abaque Series peristaltic hose pumps specifically for the mining industry.

The new models include a stronger and more durable rotor design and patented hose holding system to manage the challenging requirements of mining applications.

Featuring a seal-less design that eliminates leaks and product contamination, Abaque pumps are well-suited for a variety of mining applications, including wastewater, slurry transfer, thickener underflow, recirculation, reagent dosing, froth flotation, cyanide processing, and filter press.

The pumps contain no moving 4

parts that come into contact with the product, making them able to handle slurries that contain up to 80% solids.

The self-priming pumps can run in forward or reverse and offer suction-lift capabilities to 9m, as well as the ability to run dry without adversely affecting performance, pressure, and accuracy (no slip).

Abaque pumps are constructed of ductile iron and stainless steel, allowing higher discharge pressure to 15 bar.

The Abaque Series’ pumping action is achieved by compression of a circular loop of elastomeric hose with two diametrically opposed rotating shoes that force the fluid in the hose to move ahead of each shoe.

When each shoe reaches the end of the loop, the reinforced hose immediately returns to its original shape, ensuring

suction and priming, creating a strong vacuum pulling more fluid inside.

The working principle allows the pumps to feature high performance, low water consumption, reduced downtime, low maintenance costs, increased reliability and the ability to handle extremely abrasive and aggressive fluids.

The hoses are available in natural rubber (highly resilient with good abrasion resistance and strength), Buna-N (highly wear resistant to oily products), EPDM (high chemical resistance when handling concentrated acids, alcohols, and ketones) and Hypalon (resistant to chemicals, temperature extremes and ultraviolet light).

Abaque pumps are available in 13 different sizes, with flow rates ranging from 15 to 77,000l/hr. z

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016

PUMP NEWS

Latest Wangen progressing cavity pump offers simple maintenance and operational safety German pump manufacturer Wangen Pumpen has added the Wangen Xpress series to its portfolio of progressing cavity pumps specifically designed for easy maintenance and operational safety.

The new series of pumps targets companies specialising in wastewater treatment, biogas production, and industrial plants that convey highly viscous fluids and abrasive sludge and require a speedy maintenance of its pumps.

The Wangen Xpress progressing cavity pumps are available in two sizes, with the Wangen Xpress 48 offering pumping volumes up to 18m³/h and the Xpress 64 volumes up to 56m³/h with a maximum differential pressure up to 6 bar.

Both pumps are suitable for conveying abrasive and fibrous sludge, such as dewatered sewage sludge, as well as liquid manure or fermenter recirculate during the production of biogas.

The Xpress pumps also offer complete in-place maintenance capability and operation safety.

Complete in-place maintenance means that the plant operator is able to replace all of the

pump’s wear parts without the usual dismantling of pipe connections.

To achieve this, the Xpress is equipped with a tiltable pump set, which enables replacing the rotor and stator by simply tilting upwards or sideways.

This saves the operator considerable space and time during servicing as only a few simple steps and four standard tools are required for maintenance.

The shaft seal can also be replaced quickly and easily via the drive side, and due to the compact dimensions of the pump series, all work can be performed by a single person.

The in-place solutions previously available in the market have featured an additional pressurised joint in the pump’s interior, which enables rotor and stator replacement in installed condition, but also increases the risk of leakage.

By contrast, the discharge flange in the design of Wangen Xpress removes the need for an additional interior sealing joint, meaning that pump failures cannot be caused due to product leakage.

Both Xpress models are supplied with a standard wear-resistant cardan joint for maximum operational safety. z

Flux horizontal container pump certified explosion-proof The horizontally installed compact Miniflux container pump

by German manufacturer Flux has been approved for use in explosion hazard areas (Zone 1).

The pump was designed for draining IBCs via their floorlevel outlet and is an alternative to vertical immersion pumps.

When accessing IBCs from above is impossible or very difficult, such as when containers are stacked or ceilings are low, the Miniflux enables pumping directly at the floor-level outlet.

It is suitable for media with a viscosity of up to 1,000mPas. In comparison to gravity draining via the IBC outlet tap the Miniflux enables a considerably higher delivery rate and delivery head.

Depending on the media and motor, either up to 240l/min can be transferred or a delivery head of up to 13mwc can be achieved.

This means that the media can be rapidly filled into the container or transported to an elevated container.

The mechanical seal design separates the media area from the pump drive, meaning the shaft only comes into contact with the product in the rotor area.

The pump is only 136mm long and weighs just 1.2kg, making it easy to handle and it requires minimal space.

It can be easily connected to the IBC with a union nut.

Ideally the drive of the Miniflux is provided by a commutator motor or compressed-air motor. z

Flow Pulse Flow Monitor Designed to reliably monitor flowrates of liquids and slurries in pipes to 1250mm dia and 20mm wall thickness. Non invasive.

Clamps onto the outside of the pipe. DSP technology ensures reliability. ● Fixed or portable versions ● Simple pipe strap fixing ● 4-20mA output/ Modbus and relay alarm Contact us today for information

Malvern, Worcs WR14 1JJ, UK Tel: +44 (0) 1684 891 371 info@pulsar-pm.com

Wangen Xpress pumps handle thick and viscous liquids

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016

www.pulsar-pm.com

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FLOWMETER NEWS

Emerson adds native Ethernet connectivity to Coriolis transmitter Emerson Process Management has upgraded the Micro Motion Model 5700 transmitter with a native Ethernet connection to improve connectivity and functionality.

The native Ethernet upgrade includes dual redundant Ethernet ports, directly integrated in the device with no need for extra converters or adapters.

The dual port architecture means multiple devices can be installed in a variety of configurations, minimising wiring and switch needs for space and cost savings.

Additionally, the transmitter incorporates a configurable I/O channel that can be used as a discrete input or set to a mA, frequency, or discrete output, which enables powerful application options with minimal equipment.

the frequency output enables a quick connection for proving applications, or the mA output can be used to tie into existing or legacy control systems.

The Ethernet upgrade is available with multiple protocol choices including EtherNet/IP, Modbus TCP, and Profinet.

To speed up integration and connection with Ethernet/IP systems, the transmitter contains an electronic data sheet (EDS) file for fast access to instrument information with little to no manual set-up.

This also enables automatic addon profile (AOP) generation for quick and powerful system integration.

Pre-configured input assemblies allow users to select exactly what is needed from a wealth of information in a Coriolis meter, without burdening

to users. The rugged housing is certified for tough field environments, including extensive hazardous area certifications and approvals,” said Jason Leapley, product manager at Emerson Process Management.

“The housing was engineered to provide easy access for installation,

For example, the discrete input can be used as a totaliser reset, the discrete output can control a valve in conjunction with the integrated batch control software,

the network with unwanted traffic.

“The Micro Motion Model 5700 Coriolis transmitter has delivered proven value and unique differentiation

mounting, and maintenance. Now, with the option for native Ethernet, users can easily access process information without going out to the instrument.” z

Emerson’s upgraded Micro Motion 5700 transmitter increases the ease of installation

CORRECTION: Liquid Controls acquires flowmeter maker Avery-Hardoll In our March/April issue, Fluid Handling International reported that the fluid metering product line of Avery-Hardoll had been acquired by Avanti.

In correction to this story, the Avery-Hardoll flowmeter business

has in fact been acquired by Liquid Controls, and not Avanti.

Liquid Controls, an Idex Energy & Fuels business, purchased the Avery-Hardoll fluid metering product line from Meggitt Controls in December 2015. z

Badger Meter releases hazardous location option for Coriolis flowmeter Badger Meter has released a new explosion-proof transmitter with intrinsically safe sensors for its RCT1000 Coriolis mass flowmeters.

The hazardous location certification opens up an array of new applications for RCT1000 flow meters, including chemical and petrochemical processing, oil exploration and refining, and a wide variety of industrial processing applications in potentially hazardous environments.

The hazardous location certification applies to the RCT1000 dual tube Coriolis flowmeters with ½-3” connectors and includes low flow options.

The Coriolis flowmeters are certified for Class I, Division 1 area and include a newly designed, integrally mounted, explosion-proof transmitter.

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The new transmitter offers an unlock feature to prevent accidental activation, as well as a local LCD display with optical buttons, which allow the operator to navigate the display through the glass without opening the enclosure.

In addition to meter configuration, RCT Console software provides data logging, trend analysis, and the HealthTrack feature allowing for advanced diagnostics of a flow process.

“With hazardous location certifications and a more compact integral transmitter, we have significantly expanded the functional capacity of RCT1000 Coriolis flow meters,” said Cheryl Ades Anspach, marketing manager at Badger Meter.

She added, “The RCT1000 line is now able to help businesses in industries

such as oil and gas, petrochemical and processing, optimize their operations by controlling process flow with a highly accurate and intelligent flow measurement system.”

The Badger Meter RCT1000 Coriolis mass flowmeter identifies flow rates by directly measuring fluid mass and density over a wide range of fluid temperatures and viscosities with a high degree of accuracy.

Furthermore, the unobstructed, open flow design and measurement technique makes the RCT1000 suitable for a variety of fluids such as vegetable oils and fats, slurries, adhesives, coatings and hardeners, chemicals, petrochemicals, and other viscous, nonconductive fluids that are difficult to measure with other technologies. z

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016

OTHER NEWS

New analyser management solution provides cost savings for oil industry The Dutch plant IT and engineering specialist Hint has introduced the AML automation solution for industrial production locations to provide infrastructure to manage and maintain online analysers, flowmeters, and transmitters.

The analyser management, metering, and loading (AML) solution increases the reliability of measurements and contributes to an efficient operation, Hint says.

Online analysers measure and analyse product flows at plants, drilling platforms, or drilling wells.

This yields data about produced quantities and quality, which is used to determine revenues of measurement stations, wells, concessions, and reservoirs (allocation).

Analysers are also required for measuring emissions and monitoring process safety, both of which are required by law.

With AML, operators and managers can monitor the performance of analysers, and perform maintenance, and the software package provides an easy way to understand plant processes.

As the performance of analysers and flow equipment improves, the equipment becomes more reliable for the operation and it functions on spec.

Maintenance costs are reduced and the entire plant will be able to run more efficiently.

“Companies in energy production want to do more with fewer people and deliver higher quality at lower costs. Loss of product must be kept to a minimum,” said Wout Last, president at Hint.

“Until recently, there was little investment in digital technology to optimise the operation, but I see that changing now,” he concluded. z

Yokogawa begins production of differential pressure/pressure transmitters in India

Yokogawa India, a wholly owned subsidiary of Yokogawa Electric Corp., has launched production of Yokogawa’ DPharp EJA-E series differential pressure/ pressure transmitters in India.

The decision to launch production in India comes in response to a rising demand for control devices in the country’s market, which has been driven in part by Indian government policies that seek to foster stable growth in the mid-to-long term through the promotion of projects for the construction of oil, petrochemical, and power plants and other types of industrial infrastructure.

The launch of production in India will allow Yokogawa to better meet the needs of its Indian customers by, for example, speeding up product delivery and providing customized solutions, the company says.

To start, three DPharp EJA-E series products that are in particularly strong demand will be produced in India, and other products may be added at a later date.

Already one of the largest suppliers of

differential pressure/pressure transmitters in India, Yokogawa aims to capitalise on the high growth in this market to expand the scale of its business.

In India, the company is targeting the annual production of 100,000 units by fiscal year 2020.

Differential pressure/pressure transmitters measure pressure, flow rate, and liquid level, and play an important role in the oil, petrochemical, chemical, iron and steel, power, and other industries in processes that involve the handling of liquids, vapours, and gases.

Globally, some 300 billion yen (appr. €2.4bn) worth of these transmitters are sold each year, making this the largest segment in the field instrument market, according to Yokogawa’s 2016 market survey.

In addition to the new Indian facilities, Yokogawa has production in Japan, China, the US, Bahrain, Singapore, and Brazil, and the company is also planning to begin producing the differential pressure/pressure transmitters in Russia, Germany, and Saudi Arabia. z

Griffco Valve introduces new pulsation dampeners for chemical feed systems Griffco Valve, based in Amherst, New York, has introduced its new line of pulsation dampeners to enhance the performance of chemical feed systems.

The addition of a Griffco pulsation dampener to a pumping system will reduce harmful shock waves and deliver continuous chemical dosage at the injection point, according to the company.

In an initial release, nine volumetric sizes are offered ranging from 6.0 to 125.0 cubic inches with a dampening effect of ±2.5%, with larger sizes to be released at a later date.

An interactive pulsation dampener sizing calculator on Griffco’s website enables operators to select the correct size unit based on their volume per stroke, mean system pressure, type of pump, type of gas, and desired dampening effect.

Griffco’s new pulsation dampeners The new Griffco pulsation dampeners have maximum are available in a variety of body and pressure ratings of 17 bar for metallic models and 10 component materials bar for plastic models operating at up to 21°C. Connection sizes include 1/2”, 3/4”, and 1” (DN 15, DN 20, and DN 25) in NPT, BSPT, Socket, Union, or Flange connections.

Gauge port sizes are offered in 1/8”, 1/4”, and 1/2” (DN 6, DN 10, and DN 15).

Manufactured in the US, the dampeners feature a choice of moulded Noryl, PP, PVDF, or 316 stainless steel construction.

The diaphragm is supplied in EPDM standard, Viton, or Hypalon optional, and the gauge and charging valve materials are brass (standard) and 316 stainless steel (optional). z

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016

7

PRODUCT SHOWCASE

SEISMIC SAFETY SWITCH PROVIDES HIGH-INTEGRITY PROTECTION n The SA safety seismic switch from Sensonics is an innovative seismic monitoring and protection system trusted by the UK nuclear industry. The SA-3 seismic safety switch provides triaxial vibration detection and is wellsuited for protecting vulnerable structures from groundborne vibration events and incorporates a range of safe shutdown options, depending on the application.

The SA-3 model features three high-integrity low-noise piezoelectric seismometers positioned at 90° to each other along with the associated alarm circuitry housed within a robust weatherproof painted steel enclosure. The sensors consist of a unique system of matched piezoelectric elements arranged in a “reciprocal” configuration providing a functional test capability.

Other possible applications include oil and gas and pharmaceutical installations where accurate detection is of importance.

PRESSURE TRANSDUCER FOR HIGHLY CORROSIVE MEDIA n The Afriso HydroFox DMU 09 pressure transducer is a screw-in probe for electronic, continuous level measurement in highly corrosive media, such as chemicals or landfill wastewater. The probe is inserted into the medium from the top via a cable gland (PG 11). It is supplied via a 5m FEP cable with integrated breather tube for reference to the ambient atmospheric pressure.

A capacitance measuring cell integrated into a chemicalresistant polypropylene housing serves as the basis of the pressure sensor. The sensor element does not require transmission liquid in the measuring cell.

Therefore, the medium cannot be polluted in the case of damage. The probe DMU 09 converts relative pressure in the pressure ranges 0/40 mbar to 0/10 bar into a proportional 4-20mA signal at high accuracy (< ± 0.35 % FSO).

CONTINUOUS MONITORING OF WATER PARAMETERS n The Type 8905 online analysis system from Bürkert is a modular system for monitoring all important water parameters with one platform. The basic version provides standalone sensor cubes for five measurement parameters: pH value, redox potential (ORP), conductivity, free chlorine and turbidity. The turbidity measurement can now be conducted in accordance with the US Environmental Protection Agency standards.

Bürkert designed the MS05 sensor cube for the turbidity measurement for operation on the fluidics backplane in the Type 8905 system. Continuous analysis of water’s turbidity allows detection of undesired non-dissolved substances in the water. The measurement can indicate the filter efficiency, for example, and therefore is the basis for optimisation of the filter stage, including integrity tests. In the best case, this saves water and energy.

HIGHLY EFFICIENT SUBMERSIBLE MOTOR PUMP FOR A BROAD RANGE OF APPLICATIONS n KSB Aktiengesellschaft’s Amarex KRT submersible motor pumps are used for handling all kinds of municipal and industrial wastewater. Their maximum flow rate is 10,080m3/h and the highest head 120m. With 850kW, the pumps offer the high motor power as standard.

The impellers’ free passages comply with applicable standards. To offer as broad a range of applications as possible, the pumps are available with four different improved impeller types.

Depending on the intended system’s load profile, operators can choose a highly efficient motor variant which corresponds to the IE3 efficiency level for standardised motors in accordance with the IEC-60034-30 standard. Such motors are particularly interesting for powerful pumps with a high start-up frequency. Two bi-directional mechanical seals reliably protect the motor space against ingress of water. A chamber filled with environmentally friendly oil ensures cooling and lubrication of the mechanical seals even when gas-laden fluids have to be pumped.

Want your product here? Email georgina@fluidhandlingmag.com 8

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016

VALVES

Fast action for safety With double block and bleed installations, the safety of the valve system can be dependent on the valves’ closing speed In a small yet significant amount of applications where Class VI sealing and double block and bleed is required, there exists a limited amount of possible valve choices for the customer. Usually this type of tight shut-off requires a valve with resilient seating. But first, a misnomer that has existed for years has to be clarified.

There is a difference between double block and bleed and double isolation and bleed. In a majority of cases where the specifications call out for double block and bleed (DBB), the valve required and expected is actually a double isolation and bleed (DIB) valve. The American Petroleum Institute (API) did finally revise the nomenclature in the 23rd edition of its purchasing guidelines handbook and now differentiates between DBB and DIB, which is a very important distinction.

Fast closure In the case of DIB valves that provide a true DBB, each independent of the other and each in series to the other with a bleed between both blocks, sometimes a fast closure is required. Typically, the DIB valves are designed as expanding plug valves. These go under various different names, some of which include Truseal, Twin Seal, Omniseal, Control Seal, and so on.

This design is one where sealing slips with an embedded elastomer are retracted from the seat areas before rotation of any type. Elastomers are excellent sealing materials under compression, but their resistance to damage under shear is poor. Thus, the inherent design of the expanding plug valves ensures shear forces are eliminated and compression forces only act to seal the valve.

The compression force is a result of the tapered plug – on which the slips ride – being vertically raised or lowered, thus increasing or decreasing the relative

width of the slips. When the relative width is increased, it pushes the slip against the body seat. When the plug is raised and thus the relative width is decreased, the slips are pulled away from the body seat. Only then does the plug turn to the open position. The reverse occurs to close the valve.

This mechanism on a large valve using an operator can require 20, 25, 30 or even more turns to fully cycle the valve. Many times actuation, usually electric, is required. The dilemma here typically is the fact that the valve takes 20 to 60 seconds to fully cycle. This is due to the fact that when the valve goes from open to closed position: • The plug needs to turn 90˚.

• The plug needs to move vertically down, thus forcing slips against both sides of body seats (upstream seat and downstream seat) upon closure.

When going from closed to open: • The plug needs to move vertically up, thus retracting slips from both sides of body seats (upstream and downstream seats) upon opening.

• When fully risen, the plug again needs to rotate 90˚ to open position.

If a faster electric actuator that has a RPM of 100-150 is used, operators are forced to move to large actuators as RPM and torque are inversely proportional. There are also overruns that cause setting limit switches to be inaccurate. If an operational time of six seconds (typical on some applications) is needed for a 20” valve that has 46 turns to open, it would require an RPM of 460, which is not feasible for any electric actuator.

A hydraulic solution

in a linear motion. The design achieves the required turn and drop to close and lift and turn to open functions required for this valve type. The actuator operates under typical plant hydraulics pressures of around 70 to 90 bar. Special burst disks are installed to ensure any possible overpressure does not damage the valve, as the forces operated by the actuator are quite large. The “thrust” (as opposed to torque) keeps the valve elastomers compressed during closure.

The typical application for the actuator is one where cross contamination needs to be limited during product change. A valve that takes 30 or more seconds to close allows flow until the valve is fully closed. A valve that closes in six seconds results only in one fifth the product mixture. With these hydraulic actuators, a 20” or 24” expanding plug valve can achieve full cycle in six seconds, for example, instead of the 30 seconds an electric actuator with an RPM of 92.

Bigger valves require an even higher RPM, yet a hydraulic actuator can cycle in the six second range if required.

A note of caution, typically a safety factor of 25% to 50% in torque output over valve torques is specified for electric actuators. This should not be accounted for with hydraulic actuators, as they create thrust, not torque. With a hydraulic actuator, a 50% safety factor will result in several tens of thousands of additional foot/lbs of thrust, which can and will damage the valves.

Hydraulic actuators sized for the valve size, class, and maximum Delta P do not require a safety factor. The thrust generated by the correctly size actuator is sufficient to achieve proper sealing. z

The HXP line of Omni hydraulic actuators can operate the expanding plug valve in six seconds as the actuator operates

This article was written by Fred Turco, VP of marketing at Omni Valve.

Visit: www.omnivalve.com

For more information:

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016 9

Disasters waiting to happen

VALVES

The latest silo protection technology provides much more than a safety system to prevent over-filling and over-pressurisation

With the lid removed, this pressure relief valve has become completely blocked with product blown out during filling

A PRV that is completely blocked cannot open to relieve pressure inside the silo

Many lime storage silos at water treatment plants are disasters waiting to happen, putting lives at risk and posing serious threats to the environment. Water companies are already under pressure to minimise the impact of treatment works on the local environment, especially in terms of odour and pollution. The potential for dust pollution from storage silos with ill-equipped protection systems adds another dimension to this. However, this threat is totally avoidable.

Powdered lime is used during the treatment of wastewater to reduce odour in raw, primary sludge as a cost-effective alternative to using digesters. It is also used in other water treatment processes to help balance pH levels and as part of composting processes for sludge removed from the bottom of primary tanks after it has been de-watered and compressed. The lime and remaining water in the sludge together creates a heated chemical reaction, accelerating the process.

Level measurement specialist Hycontrol has been designing specialist silo protection systems for over 20 years and has extensive experience of the potential problems that exist on sites, especially in the wastewater industry sector.

“Our findings are worrying to say the least and the photos taken by our installation engineers speak for themselves,” says Hycontrol’s managing director Nigel Allen. “Companies just don’t seem to understand the consequences of poorly maintained protection systems. It’s quite frightening that operators accept pressure blowouts via the pressure relief valve (PRV), erroneously citing that ‘It’s OK – the PRV is doing its job’.

“This couldn’t be further from the truth – PRVs are there as a last resort. If the silo protection system is working correctly and is fitted with an automatic shut-off feature to prevent over-filling, the PRV should never be used. If a PRV blows then there’s an inherent problem with the system or the filling protocol and corrective action must be taken.

“Material in and around a PRV is a tell-tale sign that there’s something wrong and a catastrophic blowout is waiting to happen,” continues Allen. “The material blown out from the silos will almost certainly solidify over time and this will, at best, prevent the PRV from working correctly and, at worst, completely clog it up. Unfortunately many maintenance engineers just don’t realise the potential dangers that lurk beneath. They often think that simply cleaning off the material on and around the PRV is good enough. They don’t realise that if the PRV doesn’t lift next time an ‘event’ occurs, the over-pressure could easily rupture the silo or eject the filter housing from the top. On an ATEX-rated silo, the over-pressure could be sufficient to simulate an explosion and open the protective blast panels, resulting in costly loss of product and silo contents being left open to the elements.”

With regard to filter housings, Hycontrol engineers have witnessed another worrying practice at a number of sites where companies fit chains to prevent the housing being blown off the top of the silo, almost accepting the inevitable is going to happen.

What causes over-pressurisation problems?

It is hard to believe there is a PRV buried under all this product!

10

Silo protection systems are designed to prevent the damaging and potentially dangerous consequences of silo over-filling or over-pressurisation when powdered material is being transferred pneumatically from road tankers to silos.

Unfortunately, perched out on the top of silos, such protection systems are all too often “out of sight – out of mind”, that is, until a major problem occurs.

Problems during the filling process usually arise through an inherent problem with FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016

VALVES the silo protection system or with the air filtration system on top of the silo. Problems can also occur through tanker driver/operator error.

Delivery tankers are pressure-tested vessels typically capable of withstanding up to 2 bar (29psi) pressure. Storage silos are designed to withstand the weight of material stored in them and can rupture at pressures as low as 1-2psi above atmospheric pressure.

The consequences of over-filling or over-pressurisation include: • Serious or fatal injury to workers and the public • Catastrophic silo damage • Loss of material and production • Harmful environmental pollution • Damage to company reputation A key issue with many silo protection systems is that without adequate ground level testing capabilities, operators do not know if they will work when needed. Working at height restrictions limits silo top inspections and maintenance, especially in adverse weather conditions. However, the main question is what can engineers actually do when they are on the top of the silo? And furthermore, how does one physically test a relief valve or pressure transmitter without removing them?

Even if the protection system does do its intended job and prevents a major incident, companies rarely investigate the root cause of the problem so that remedial work can be carried out to prevent the situation re-occurring. Important “near miss” events such as PRV lifts, high level events, and high pressure events are routinely not recorded and often conveniently dismissed. Hycontrol has clear evidence that in practice there are more “near misses” than realised and that the situation is a ticking time bomb.

Filter housings at the top of the silos are designed to vent the silo during filling, whilst preventing dust escaping into the atmosphere.

Normally these are fitted with some form of self-cleaning system to keep filters clear. These are typically mechanical shakers or reverse jet systems. Although filter manufacturers give recommended check routines and filter replacement schedules, in practice it would appear these guidelines are regularly ignored. Faulty operation can be caused by a range of issues, including blockages and the fitting of unsuitable or wrongly-sized filters. Most powders form hard compounds when mixed with water from the atmosphere, further exacerbating the problems at the top of the silo.

Effective silo protection The Mineral Products Association (MPA) publishes comprehensive guidelines for silo protection systems in quarries and cement works, but there are little or no such recommendations for powder silos used in a broader range of industries, including wastewater treatment, food and beverage, chemical, and plastics. However, the primary principles are the same for protecting any pneumatically filled silos.

Even with guidelines in place, the benchmark for the effectiveness of any silo safety protection system can only relate to the last time all the components were fully tested.

Optimum solution The only effective solution is to take an integrated approach to silo protection design whereby the PRV, pressure sensor, and high level alarm can be tested at ground level, prior to each fill. Only when all these safety devices have passed the checks should the safety interlock allow the silo inlet valve to open and the delivery to commence. The use of a groundlevel test (GLT) system, as utilised in Hycontrol’s Silo Protection

A newly-installed silo protection system with a pressure sensor, a level sensor, and a testable PRV

System, will also eliminate the risks of working at height.

As an added benefit, an effective protection system can serve as a powerful predictive maintenance diagnostic tool by recording critical near miss events that occur during the filling process. This information allows managers to carry out effective predictive maintenance by means of a logical step-by-step root cause analysis (RCA) process to understand why the problems are arising. For example, high pressure and PRV lift events may be due to filter problems, prompting questions such as: • Are the filters the correct size?

• Is the filter cleaning regime fully operational?

• Have the filter bags/cartridges been changed as per manufacturers’ recommendations?

In parallel the logs will also indicate if the tanker drivers are routinely overpressurising during the fill process. In summary, the optimised silo protection system should incorporate: • Pressure sensor, high-alarm level sensor, and PRV testing (essential) • Simple one button press to test all components • Silo filling auto shut-off control • Pneumatic cleaning of pressure sensor • Recording of the number of events on incidents of over-pressure (time/date stamp) • Recording of the number of events of PRV lift and opening (time/date stamp) • Recording of the number of events of high level probe activation (time/date stamp) • Filter ON/OFF output option to check filter status • Filter air supply monitoring alarm option Conclusion There is strong empirical evidence that many silos are disasters waiting to happen. The practical reality is that powder storage silos can split or rupture at pressures as low as 1 or 2psi above atmospheric pressure. Malfunctioning filter housings can be ejected at similar pressures.

Cursory visual inspections of silo protection equipment are woefully inadequate. Therefore, it is imperative that any installed safety system must be capable of providing reliable protection that can be easily verified by testing critical components before each and every delivery – without having to climb to the top of the silo. This approach will provide total silo safety, protecting the surrounding environment, assets and – most importantly – site personnel and the public. z For more information:

This article was written by Nigel Allen, managing director at Hycontrol.

Visit: www.hycontrol.com

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016 11

VALVES

The many colours of the butterfly Butterfly valves are increasing their popularity in modern piping solutions, and for a good reason

A hygienic actuated butterfly valve

12

Butterfly valves are being used more and more in modern piping and distribution systems. They offer the user a cost-effective alternative to more traditionally used valves such as ball, diaphragm, gate, and globe valves. Butterfly valves, depending on specification are designed to handle a wide range of conditions and media including corrosive chemicals, water, seawater, gases, alkalis, acids, hydrocarbons, plus many others. When applications demand special requirements, suitable materials can be chosen to meet these needs.

These include: carbon steel, stainless steel, aluminium bronze, Monel, Hastelloy, titanium, Duplex, and Super Duplex.

The benefits of specifying butterfly valves are: i) Cost savings on installation and maintenance are substantial, delivering maximum ROI ii) Lower cost per unit on larger or comparable size valves iii) Efficiency savings over traditional valves with reduced downtime iv) Proven performance in demanding high pressure applications Valves can also be supplied with manual operators or fully actuated though pneumatic, electric, hydraulic (counterweight), or electro-hydraulic technology, offering a truly flexible solution to meet operators’ needs.

The launch of actuated butterfly valves, following the introduction of actuated ball, diaphragm, gate, globe, and knife gate valves, delivered users and installers with an economical alternative in sizes 4” and above.

Actuated butterfly valves help to create an extensive range of process solutions in larger sizes. They are generally a better choice for isolation above 4” due to their lighter weight (in larger sizes) when compared to alternative types of valve. This in turn makes them easier to handle and install.

It is therefore fair to say that the actuation of manual butterfly valves is an integral

A double offset valve

part of modern process automation, as the following three examples demonstrate.

HVAC – hospital The problem Ten years ago Viton liners were the only sensible option available for industrial hot water systems. They were only reliable for a limited amount of time when in constant use. A local hospital had an existing heating system in place with long runs of solid pipe work which needed to remain due to cost. The valves within the system, however, were beginning to fail.

Over time the Viton liner had degraded and had started to leak when closed, causing unnecessary and costly heat loss.

With more than 100 valves in the system that needed to be replaced, a like for like valve seemed to be the only viable solution as far as the client could see.

The solution A double offset butterfly valve was offered as a direct replacement, fitting onto the existing flanges and in the available space without the need to replace any pipework.

Double offset butterfly valves work well FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016

VALVES of cooking sauces. Operators require a valve that can handle cooking sauces: 1. With or without solid ingredients 2. At differing operating temperatures 3. That can be both manually operated or actuated, fitted with feedback

A resilient seated butterfly valve

in medium temperature hot water between 120°C and 130°C and at 4-6 bar. The new valves will remain a reliable cost-effective solution for many years to come, delivering superior life capability with zero leakage shut-off.

Food processing – cooking sauces The problem A typical processing problem that commonly occurs is in the production

The solution Sanitary (hygienic) butterfly valves tick all the boxes for this application. Hygienic butterfly valves can be supplied as both manual or pneumatically actuated.

These types of valves are suitable for CIP and come with FDA approved seats.

Feedback on these types of actuated valves can be computer controlled, delivering information on multi-stage processes applications, perfect where adding ingredients is concerned.

Marine environment – saltwater The problem An operator was using butterfly valves in a marine environment and suffering corrosion to the discs, in this case from salt water. Applications in question were desalination and shipboard systems.

Although aluminium bronze alloys were available that would prevent corrosion, the cost to install was not a viable option.

The solution Bray Controls pioneered a new type of resilient seated butterfly valve with a nylon coating on a ductile iron disc. This design delivers the benefits of a plastic valve, namely resistance to marine corrosion but with the availability, functionality, and rating of traditional resilient seated valves. The cost is also lower than using an aluminium bronze alloy disc or a comparative plastic butterfly valve.

Conclusion Butterfly valves are a good choice for improving the efficiency of systems and/ or applications. When compared with similarly rated ball, diaphragm, gate and globe valves, the weight reduction, space-saving design, and benefits that butterfly valves offer is clear to see. z For more information:

This article was written by the technical team at Valves Online Limited. For more information visit www.valves-online.co.uk

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Then we would recommend a dedicated email blast to our 10,000+ subscribers.

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FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016

13

VALVES

Dampening the blow High-performance damper drives are necessary for ensuring operational safety in several fields Actuated dampers are key to the provision of efficiency and safety in numerous environments affecting industry and the public at large. Critical applications are found in areas as diverse as road and rail tunnels, mines, offshore platforms, commercial shipping, cruise liners, power stations, and process industries. In each environment, the correct choice of available actuation technologies ensures that efficient and often vitally important operating demands can be met. For example, in road and rail tunnels, dampers installed for the provision of essential ventilation must also be able to swiftly react to potentially dangerous and life-threatening events.

The Istanbul Metro is a case in point. The subway system is undergoing a significant expansion programme involving 900km of new routes that are due for completion by 2023. Tunnels on the new routes are fitted with ventilation dampers in sizes up to 2m2 and to meet stringent safety standards, the actuators operating these dampers must be able to rapidly close them and shut off the airflow in the event of a fire.

Rotork RC200 high temperature specification pneumatic actuators were selected for this application due to their compact design, the fast operating capability inherent in pneumatic operation, long-term reliability, and minimum maintenance requirement. The scotch-yoke actuators had to pass the stringent temperature and cycling tests required to meet the high level of safety demanded by the application. These included heating the actuator from -5째 to 250째C in only 20 seconds and then confirming reliable operation with no air leakage for a minimum period of one hour at the maximum temperature.

Marine and offshore Damper applications in the offshore and marine industries are widespread, 14

the dampers to their safe position when a pre-set temperature is reached. This innovative and reliable solution is widely specified for fire damper applications.

Wide range of applications ExMax and InMax actuators are part of the range of electrical products designed

Rotork Schischek actuators (blue enclosures)

encompassing HVAC and air flow control applications. Recent examples have included the selection of Rotork Schischek electric actuators for the motorisation of air control dampers manufactured by Nailor Industries at their Houston, Texas, facility for an offshore drilling platform owned by the Mexican state-owned petroleum company Pemex. The stainless steel dampers are fitted to sea containers housing power generation equipment.

Explosion-proof Schischek ExMax quarterturn failsafe actuators are being supplied

by Saturn Enterprise of Dallas as part of an order which represents the first application in the offshore hazardous area air damper OEM market for Nailor.

Schischek HVAC electric actuators have also been specified for critical fire damper operating duties on a fleet of cruise liners based in the USA. The specialised fire and gas dampers manufactured by Wozair protect redundant emergency power generation plants installed on the liners to ensure that vital facilities including catering, air conditioning, and sanitation can be maintained in the event of a failure to the main power generators.

In this case, Schischek InMax actuators have been selected for the application, equipped with temperature activated safety triggers which automatically move

by Schischek for explosion-proof and safe area HVAC applications in the worldwide industrial, offshore, and marine industries. Compact actuator dimensions are generally advantageous for damper actuation applications and particularly relevant for offshore and marine damper applications. A major benefit of the Max actuator range is its compact size and footprint, which is unique for an explosion-proof actuator. It enables direct mounting on the damper and facilitates installation within the airstream, removing the concerns about space restraints around the damper casings, which are often encountered. Further Schischek benefits include a universal 24 to 240V AC or DC power supply, an integral failsafe option with one second travel time, and compliance with all major international explosion-proof certificates.

Designed and manufactured to the highest possible standards and in accordance with ATEX94/9/EC, Schischek actuators are suitable for operation in Ex zones 1, 2, 21, and 22 where gases, vapours, mists, and dust may be present in the environment. Widespread applications include many industrial processes that use potentially explosive media, extraction units in tunnel systems, or air flow control units in chemical laboratories, dust extraction systems in paint lines, wastewater plants, container ships and tankers, oil and gas platforms, and gas pipeline compressor stations.

The complete Schischek product range encompass rotary and linear electric actuators and control systems providing

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016

VALVES on-off and positional control for two- and three-way valves and dampers, including spring-return options. Actuator ranges are complemented by transmitting and switching sensors for differential pressure, temperature, and humidity and other accessories including door holder magnets. The products are used throughout the world and are approved and certificated by Ex, UL, CSA (both US and Canada), ExGostR, and IECEx. The products are also IP66 and SIL2 rated.

All Schischek products are manufactured with colour coding to indicate at a glance the appropriate hazardous or non-hazardous area of application. Yellow denotes hazardous Zones 1, 2, 21, and 22, red denotes

defined temperature to produce the biogas. For optimum performance, the inner tank temperature must be maintained at 38°C. ExMax actuators are installed in an area known as the lamp at the top of each tower for the operation of air dampers to balance the inside temperature with fluctuating ambient temperatures on the outside.

Power generation The power generation industry is subject to ever stricter demands from environmental legislation for increased efficiency and control of emissions from industrial boilers, furnaces, and other power plant processes. For example, in the US the

Actuator installation on an air damper at the Munich wastewater plant

hazardous Zones 2 and 22, and green denotes non-hazardous areas only.

In an example of a process industry application, Schischek ExMax explosion-proof actuators are assisting the production of biogas for district heating systems in the German city of Munich. Biogas is produced during the effluent treatment process at the city’s largest wastewater plant, Klaerwerk Gut Grosslappen, situated close to the world famous Munich Allianz Arena, home to Bayern Munich football club.

The ExMax actuators have been installed in the digester and fermentation tanks, where all electrical equipment must be approved for use in hazardous areas. Built inside four large towers, the fermentation tanks mix the waste at a

Rotork Type K damper drive unit

Environmental Protection Agency (EPA) has introduced the MACT (Boiler Maximum Achievable Control Technology) Rule requiring operators to carry out tuneup procedures either annually or biannually, affecting an estimated 14,316 boilers and process heaters, whilst other nations’ legislation is equally onerous.

The precise and swift operation of dampers for the accurate control of combustion air and flue gas is essential for the achievement of reduced emissions, improved boiler draft control, and lower fuel consumption, which can also result in dramatic cost savings.

However, many boilers still employ old technologies that are not accurate or powerful enough to position the dampers with the necessary speed to meet contemporary requirements.

Replacing obsolete equipment with fast acting vane type pneumatic damper drives, such as the Rotork Type K, offers advantages including improved burner management and cleaner performance. In addition, the Type K offers a swift “drop-in-place” retrofit solution that precisely fits the application without any field engineering or fabrication. Existing connection rods and linkages can be used without modification, and commissioning is quickly and simply completed.

Type K damper drives provide a 100% duty cycle, with a continuous modulating service rating of 3,600 starts per hour. An output torque of up to 28,200Nm is available with high speed stroke times as low as three seconds full scale. The rugged, open frame construction is designed for virtually maintenance-free operation in harsh, high temperature environments up to 150°C. The vane type pneumatic actuator delivers fast and accurate positioning and reduces overall operating air consumption. The units also offer a smoother performance. A wide range of control system interfaces encompasses pneumatic, analogue, and bus network communication systems, including Profibus, Foundation Fieldbus, HART, and Modbus open protocols.

The Type K is proven to deliver high speed continuous modulation of ID (Induced draft) and FD (Forced Draft) fans, inlet guide vanes and secondary air dampers, enabling improved burner management, a swift response to plant demand and low running costs. The wide choice of control and automation options introduces predictive maintenance

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016 15

VALVES and diagnostic capabilities to further improve long term plant utilisation.

Case study – power station The swift performance capability of the Type K damper drive has provided the successful retrofit solution to a critical application involving the safe and efficient operation of balanceddraft power generation boilers.

Inlet draft (ID) fan inlet dampers at power stations regulate the fan-induced pressure and airflow supply to balanceddraft power generation boilers. These boilers require a consistent internal operating pressure for efficient and safe combustion. Boiler pressure fluctuations create combustion problems that can, in extreme conditions, lead to catastrophic failure and structural damage. The maintenance of consistent operating pressure relies entirely on the swift operation of the ID fan inlet dampers.

At the three-unit 2735MW Florida Power & Light Manatee Power Station at Parrish, Florida, the ID fan inlet dampers demand full 90° damper movement at full torque load in three seconds or less in order to safeguard the operation of the boilers.

In a recent outage at the station it was necessary to replace the ID fan inlet damper drives on Units 1 and 2, which were over 30 years old and incompatible with the HART protocol of the station’s new distributed control system. In addition the manual overrides on the drives had proved to be unreliable.

The equipment selected to replace

The Rotork Type K damper drive drop-inplace replacement, matching the footprint of the old equipment

16

the obsolete equipment was Type K ‘PM Series’ pedestal mounted TK-6 damper drives, delivering a torque of 5000lbs-ft at a tested time of less than three seconds for a full 90° stroke. Type K provided a drop-in-place retrofit installation, matching the dimensions of the existing damper drive footprint on all eight of the replacement installations in Units 1 and 2. Integrated air volume boosters were fitted to obtain the required rotation speed and the control interface was provided by smart positioners.

Prior to delivery, Type K completed factory acceptance testing on the drives and obtained the test cycle times as recorded by the smart positioners. Test results One of the Rotork Type K damper drive installations on the SS Cape Isabel were video recorded and documented for Florida Power Replacing the actuators was necessary to & Light to review. Installation was increase efficiency, reduce maintenance followed by witnessed acceptance and the associated costs that could testing during which the drives performed result from unplanned shutdowns. as quickly and smoothly at full load The selection of Type K damper drives as the factory testing had indicated, for the upgrade provided a direct drop-incontributing to a punctual return to boiler place replacement that exactly matched readiness for electricity generation. the existing damper drive footprint and output shaft location, enabling the Case study – cargo ship upgrade to be swiftly completed in a matter of hours. Once the two Type Returning to the marine K pedestal mounted damper drive environment, the choice of Type units had been delivered to the ship, K actuators to replace existing installation of both units was performed equipment has enabled the by engineers from Rotork Site Services control upgrade of a cargo ship’s within three days. All the work was main propulsion intake dampers co-ordinated prior to commencement to be completed in three days. by the ship’s Chief and First Engineers.

SS Cape Isabel is a 655ft, Days one and two were taken up with 15,000 tonne roll on/roll off cargo the removal of the old equipment ship based at Long Beach and and the installation of new, enabling operated by the US Military commissioning, testing and hand-over Sealift Command. Launched to be completed during day three. in 1976, the ship is powered by As illustrated by these examples, two steam turbines. The ship’s a wide range of damper actuation two turbine intake radial vane technologies are available. Identification dampers were equipped with of the correct equipment for the pneumatic controllers which operating environment and duty will had become obsolete. The old assist the achievement of improved actuators did not respond quickly efficiency, reliability, and safety. z and accurately to signals from the control system, resulting in For more information: potentially inefficient combustion This article has been written by Mark Clark of FTPublicity for Rotork. Visit: www.rotork.com and undesirable emissions.

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016

Researching safety

VALVES

The fluid handling industry is collaborating with university researchers to address the causes of dynamic behaviour of direct spring-loaded pressure relief valves with inlet piping In the early 1990s, representatives of many of the major oil and gas producers surfaced concerns related to the causes Kenneth Paul, senior of chatter, technology manager flutter, and cycling at Pentair (as defined in the API 520 Standard) specifically in the operation of direct spring-loaded pressure relief valves. They were seeking a tool to determine the conditions that led these valves to becoming unstable.

When a spring loaded relief valve goes into an unstable status in a flutter case, the valve is found to exhibit a sinusoidal lift versus time oscillation that can reduce relieving capacity from 50% to 100%. In a chatter case, the valve disk starts hammering against the nozzle, causing a serious jackhammering effect that can damage the valve.

These effects can adversely affect the performance of the valve resulting in valve seat damage and the guides galling that could ultimately prevent the valve from closing and sealing.

Pentair committed to finding a solution by allocating staff and financial resources to address these issues, and in 2012 senior technology manager for research and development Kenneth Paul identified and contacted teams led by Csaba Hos from Budapest University of Technology and Economics in Hungary and Alan Champneys from the University of Bristol in the UK. These university researchers had already begun to address the causes of dynamic behaviour of direct springloaded pressure relief valves with straight inlet piping. Pentair’s collaboration with these professors and their students from Budapest University of Technology and Economics and the University of Bristol has led to additional extensive research and testing, which has thus been documented

and shared in the form of technical papers in The Journal of Loss Prevention and presentations at American Petroleum Institute (API) meetings, Design Institute for Emergency Relief Systems (DIERS) meetings, and the American Institute of Chemical Engineers (AIChE) conferences.

Research to date indicates that the cause of the oscillations observed during a pressure relieving event is the result of the coupling of the acoustic energy (organ pipe or quarter wave frequency – QWF) with the negatively damped pressure relief valve. Further, research and testing showed that the coupling does not occur at the natural frequency of the valve but at the quarter wave acoustic energy frequency. It has been proven that during these oscillations, the relieving capacity can be reduced to half of the normal flowing capacity of the relief valve. Full parametric modelling of these effects has shown to have good correlation with experimental results, leading the research teams to develop a limit for inlet pipe lengths beyond which unstable operations are predicted. Subsequently, a reduced order modelling has been presented that provides a simplified method to predict the valve instability.

Previous research of direct-spring pressure relief valves connected to a tank via a straight pipe was adapted to take the handling of liquid media and gas into account. Close agreement has been found between experimental data and simulations of a fluid coupled mathematical model for both media, which takes into account the effects of the change in sonic velocity in the pipe. Further simplification of the model has been presented as a simple analytical formula derived from the reduced-order model.

The research and testing conducted

by Pentair Valves & Controls, Budapest University of Technology and Economics, and the University of Bristol also showed that liquid service valves are found to be stable for longer inlet pipes than for the gas case. However, in the liquid case, the

instabilities – when they do occur – are more violent and the valve is found to jump straight into chatter, in which impacts were observed. Flutter-type oscillations were never observed in liquids. Water hammer effects, which result in extremely high overpressure values during chatter, have also been observed in the liquid case. Additionally, a new Helmholtz-like instability that was not encountered in gas analysis was presented for short pipes with small reservoir volumes.

Conclusions The following is a summary of significant conclusions from years of research and testing: • Researchers have been able to capture fundamental instability mechanism of pressure relief valves in both gas and liquid service

2J3 valve for gas close to instability border

3L4 valve increasing pipe lengths for 50% capacity flow rates

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016 17

VALVES • The fundamental cause of the pressure relief valve instability is due to coupled valve motion and acoustic pipe quarter-wave mode • For similar valves and set pressures, the critical pipe length for liquid instability is approximately four times that of gas • Liquid case instability is more violent and the valve jumps straight to chatter with water hammer effects • Other instabilities are cycling, Helmholtz, and static jumps

Ongoing work

• Studying blowdown effects • Testing analytic predictor of the quarter-wave instability • Understanding the effects of backpressure • Understanding more complex inlet pipe geometries

Addressing a wide range of conditions that can cause these pressure relief valves to become unstable is an ongoing effort – one that is important to all industry sectors and specifically to valve manufacturers and owners and operators of plants of all types and sizes all over the world. Some of the most critical work that is being undertaken as a next phase of research and testing involves:

Inquiries and comments welcome The nature of the research and testing of the conditions that cause direct spring-loaded pressure relief valve oscillations

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This article was written by Kenneth Paul, senior technology manager for research and development at Pentair Valves & Controls.

Visit: www.pentair.com Accompanying figures are supplied by Pentair Valves and Controls, Budapest University of Technology and Economics, and the University of Bristol

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and associated consequences in plant facilities of all types is extremely technical and complex, yet infinitely valuable. Pentair invites inquiries, comments, and feedback relative to research and testing that have been conducted to date as well as additional research and testing that can be undertaken in the future to assess valve performance under a variety of conditions and piping configurations. Please also explore the reference materials listed at the end of the article for detailed information, mathematical formulas, and diagrams. z

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Technical references Hos, C., Bazsó, C., Champneys, A., 2014a. Model reduction of a direct spring-loaded pressure relief valve with upstream pipe.

IMA Journal of Applied Mathematics 80, 1009{1024.

URL: http://imamat. oxfordjournals.org/lookup/ doi/10.1093/imamat/hxu034,

Speakers Include:

doi:10.1093/imamat/hxu034 Spyros J. Kiartzis, Director Alternative Energy Sources and New Technologies, HELLENIC PETROLEUM S.A

Raffaella Serra, Business Development Manager, Beta Renewables

Hos, C., Champneys, A., 2012.

Grazing bifurcations and chatter in a pressure relief valve model.

Physica D: Nonlinear Phenomena 241, 2068{2076. doi:10.1016/j.physd.2011.05.013.

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Hos, C., Champneys, A., Paul, K., McNeely, M., 2014b.

Dynamic behavior of direct spring loaded pressure relief valves in gas service: model development, measurements and instability mechanisms.

Journal of Loss Prevention in the Process Industries 31, 70-81.

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doi:10.1016/j.jlp.2015.04.011.

Hos, C., Champneys, A., Paul, K., McNeely, M., . Dynamic behavior of direct spring loaded pressure relief valves: III valves in liquid service.

Research article submitted to Journal of Loss Prevention in the Process Industries.

www.biofuels-news.com/conference 18

Hos, C., Champneys, A., Paul, K., McNeely, M., 2015. Dynamic behavior of direct spring loaded pressure relief valves in gas service: II reduced order modelling.

Journal of Loss Prevention in the Process Industries 36, 1-12. URL: http://linkinghub.elsevier.com/ retrieve/pii/S0950423015001151,

06/05/2016 15:39

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016

PUMPS

Resolving water hammer through transient monitoring equipment

Water hammer and pressure fluctuations can prove a constant headache to municipal water operators, but solutions to their woes may be at hand “Water hammer” is a serious concern for municipalities today in order to ensure water quality and keep fluid distribution pipelines operating efficiently and consistently without expensive downtime. Whether the application is pump station control, pressure/flow balancing, or age of water, a systematic approach is needed to prevent potentially catastrophic events from occurring. By utilising computer surge modelling software and transient monitoring equipment, the causes and effects of water hammer can be identified, analysed, and resolved through a system design solution that may involve pump control valves, surge vessels, air/vacuum valves, surge anticipatory valves, control valves, and check valves.

Site operators and managers have not traditionally had the tools necessary to assess what specifically happens when the pump(s) start/stop or when a valve is suddenly closed with the pump(s) running. The mathematical calculations for pressure surge effects are quite extensive and only through computer surge modelling can this process be conducted quickly and accurately. In conjunction with transient pressure monitoring equipment that can record data at over 100 times per second, municipal personnel will now know exactly what is happening with their pumping system and how to resolve it safely and comprehensively.

By incorporating both computer surge modelling and transient pressure monitoring at the time of identifying that a problem exists and finally, at the startup/commissioning of mitigation equipment, the selected solution can be confirmed as performing to expectations via this “proof of design” methodology. The mitigation equipment chosen (vessels, valves, etc.) can be tested and quantifiably measured with reporting results available the same day via email in either text or graphical format.

A detailed computer surge analysis study of pump stations and distribution systems, followed by proof of design of equipment during startup and commissioning, will avert hazardous and costly problems. Each step in this process will provide clarity on what can and likely will happen when surge events are not properly identified and inaccurate data leads to incorrect equipment being selected and installed.

This study provides a cautionary example of the dangers, cost, and bad publicity that can follow when pressure surge

events are not treated seriously enough with the modelling and monitoring solutions that are available today.

Health risks Naegleria fowleri, commonly referred to as the “brain-eating amoeba,” made headlines recently when it was detected in water supply systems near New Orleans, Louisiana, US. The fact that this and other dangerous microscopic organisms can enter into a potable water system through damaged piping caused by a pump trip is a possibility that operators need to evaluate and prevent. The pump trip can cause a negative transient vacuum wave below atmospheric pressure affecting the entire potable water system.

The Blacoh SurgeWave transient monitoring system will alert

Figure 1: Vertical turbine pump trip

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016 19

PUMPS

Figure 2: Water well startup

Figure 3: Check valve closing time

the operator of any transient pressure wave which drops below the minimum operating pressure of the municipality. SurgeWave employs a patented system of dynamic pressure transducers and digital technology to monitor pipelines for indefinite periods of time. When a transient such as a pressure surge, pressure spike, or water hammer event is detected, the system records the high speed data at 100 times per second. When the pressure drops back to a steady state, the system records the running average, which is defined upon startup. SurgeWave can record multiple devices to keep track of transient pressure, flow, pressure, level, air/vacuum breaker movement, and pump speed.

Figure 1 is an example of a vertical turbine pump trip. The liquid-filled pressure gauge showed the steady state pressure at 70psi and the low pressure wave pressure dropping to 50psi. The SurgeWave system recorded the steady state pressure at 60.9psi and the low pressure wave pressure dropping to 6.1psi, which is below the minimum allowable pressure for a potable water system. The differential pressure across the check valve was 0.2psi.

When the pump tripped, the upstream pressure of the check

valve dropped to -0.6psi. A properly sized pump control valve can be modelled to keep the change in velocity from dropping below the minimum operation pressure. A Blacoh Surge Vessel would have to be added to give energy to maintain minimum operating pressures during a power failure. Once the computer surge model confirmed the surge control devices, the SurgeWave system would be used to calibrate and verify the system design.

When the pump starts and the pump column pipe shaft is filled with air, there is no load on the impeller. The pump starts and runs off the right hand side of the pump curve. When the air is released through the air/vacuum valve and the air release valve closes, the pump is loaded and the pressure spikes to the left hand side of the pump curve. The upsurge pressure spike depends on the motor speed with no load, then to no flow, and the maximum pressure at zero flow. The data in figure 2 shows a water well designed to discharge 1,000gpm at 86psi.

The startup surge reaches 463psi in 0.2 seconds when the air valve is closed. The solution is to install a hybrid fluid velocity control system that controls the air velocity while receiving energy during startup and giving energy during shutdown.

The SurgeWave system can be used to evaluate check valve closing time (figure 3), actuated control valves (figure 4),

Figure 4. Actuated control valves

Figure 5. Water plant pump station

Vertical turbine pump startup surge

20

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016

Protecting your equipment makes sense Figure 6

Figure 7

and calibrate computer surge modelling input data. When the pump was de-energised, a negative wave oscillated out, the check valve closed, and created an upsurge wave.

Case study A water plant has a pressure gauge and differential pressure switch on the downstream side of the pump (figure 5). The gauge kept bouncing around and the operator could not read the gauge. They changed the gauge to a liquid-filled design, with a pressure snubber and a short piece of pipe.

The differential pressure switch is designed to turn on the pump at low set pressure and turn off the pump on high pressure. When the pump turned off at the high pressure set point, a negative wave travelled down the piping system.

The low pressure wave dropped the pressure below the low pressure set point and would trip the switch and turn the pump on again. When the high pressure wave oscillated back, the pump would switch off due to high pressure.

To solve the problem, the operator installed a timer relay to the differential pressure switch to keep the pump from energising due to pressure fluctuations caused by the initial pump trip. With the liquid-filled pressure gauge with snubber, the operator had no sign that the water pressure was dropping below the system’s minimum operating pressure. Even if the system was designed with a pressure transducer recording the pressure, it is unlikely that the system would record the negative transient wave traveling at 3,000ft/s. Figures 6 and 7 show how important it is to create a computer surge analysis and proof of design documenting transient pressures at 100 times per second. Controlling system pressure with VFD drives maintains pressure demands but does not protect distribution systems during a pump trip. z For more information:

This article was written by Frank Knowles Smith, III, executive VP at Blacoh Surge Control. Visit: www.BlacohSurge.com

Rely on Rotork Choose the Client Support Programme that suits your needs

• Protect your investment

• Increase plant availability

• Maximise productivity

• Reduce your cost of ownership Get the facts, find your nearest Rotork office or more information about the Client Support Programme at www.rotork.com T +44 (0) 1225 733200 E information@rotork.com W www.rotork.com

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016 21

PUMPS

The saint of sewage A new chopper pump has proven a godsend at a Californian rescue mission struggling with a broken-down sewage disposal system The Twin Cities Rescue Mission in Marysville, California, has been plagued by a sewage pump that constantly plugged up and broke down. Twin Cities Rescue Mission aims to provide a clean and sober community, assisting in housing and also providing food, clothing, and showers for anyone in need. It also provides a religious atmosphere and works to promote a loving and compassionate community.

But the Mission, established in 1956, finally had to bring in porta potties when its sewage pump burned out completely.

Relying on financial or food donations only, with no government funding to support its work, the Mission called upon MuniQuip of Roseville, California, for help – a specialist in fluid handling and dewatering solutions for municipal and industrial processes. To address the very unreliable sewage lift station, MuniQuip sought the most reliable, cost-effective, and long-term solution. A Landia chopper pump was considered the best option to allow Twin Cities Rescue Mission to concentrate on assisting its community’s current needs (as well as helping residents move forward in life), rather than spend valuable time on wastewater matters.

Roger Vaca, executive director of Twin Cities Rescue Mission, says: “After so many problems with the old pump, I was pretty much doing a jig to celebrate us at long last having a decent piece of equipment.

MuniQuip and Landia have been great”.

“When my wife Linda and I began here 25 years ago, the Mission served around 15-20 people. Now, we look after well over 100 guests per day, with around 50 residents staying with us every night. The old pump couldn’t cope with the increase, but it wasn’t the best anyway,” he added.

The saviour appears Vaca says that the old pump continually struggled and then began to pack up completely in the spring of 2015. The Mission tried hard to resolve everything before the rise in temperatures, but had no choice in the end but to bring

22

in four porta potties, which had to be emptied twice per week. With temperatures in California routinely exceeding 38°C, the Mission was facing a very long, hot, and odorous summer.

“Now, since its installation, the Landia chopper pump, which has to pump the sludge 1,100ft to the city sewer line, has been running fabulously. Also, because we only had single-phase 230V power available, Landia supplied us with a custom-built control panel, including a Danfoss variable frequency drive for phase-conversion in order to run the three-phase explosion-proof motor on the chopper pump,” Vaca says.

Soren Rasmussen, director at Landia, says: “We are very pleased to have been able to help Twin Cities Rescue Mission get back on track with a reliable, longterm pump solution. The Mission does tremendous work for the community and deserves every bit of support it gets”.

Landia is no stranger to resolving plugging issues with pumps, as Rasmussen explains: “Conventional sewage pumps are fine when they deal mainly with wastewater, but as is so often the case, solids and debris have a way of finding their way in, which is when problems start to arise. The situation at Twin Cities Rescue Mission came about due to the increasing demands on the system and also because the original pump wasn’t of the best quality. Modern wastewater treatment facilities are designed to account for the inevitable increases in population, but at places such as convention centres, universities, hospitals and sports arenas, where the amount of people on-site can vary tremendously, it is very important to have the right pump in place to cope”.

Rasmussen says that

the Mission’s porta potties in California were something of an exception, but nonetheless, the downtime and cost of maintenance, cleaning, and unblocking should always be brought in to the equation when selecting the right pump for one’s application.

“Landia’s chopper pumps are equipped with a hardened steel knife system that chops up solids and any stringy material prior to them entering the impeller. Our customers don’t have to build in time for unblocking. Standard so-called non-clog pumps simply cannot handle the inevitable unknown waste that always seems to find its way into a drain.

It’s not worth the risk, the aggravation, and the cost to take chances for the wellbeing of a plant’s operation,” he says.

The overflowing university Another recent example of a Landia chopper pump solving a major problem came at a major university in Washington State, which was close to sewage A Landia chopper pump proved a godsend saviour to the Rescue Mission

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016

PUMPS

The Twin Cities Rescue Mission was suffering from effluent transfer issues

overflows. The near-miss overflows at the university were being caused by the continuous plugging of an existing sewage pump, also resulting in downtime and constant, costly maintenance.

Leading equipment suppliers and advisors Mitchell, Lewis & Staver (MLS) reviewed application data and changes in the waste stream with the campus facilities manager, opting for a Landia submersible chopper pump that would be capable of actually cutting up the fibrous and stringy materials to the point that they would be pumpable.

Ty Collins from MLS comments: “More and more we see the problem of socalled flushable products that clog up so-called non-clog sewage pumps.

Standard pumps can deal with standard sewage, but they are no match for the stringy, tear-resistant synthetic fibres

of products such as wet wipes.”

“We specified a Landia chopper pump because of its proven, dual-action cutting mechanism and stationary hardened knife system. These knives chop and cut the materials prior to them entering the impeller. We’ve seen that other chopper pumps use the impeller itself as part of the cutting mechanism, but the Landia design allows for a far more effective chopping system, whilst using the impeller for pumping whatever nominal solids remain. Since the installation of the Landia chopper pump, the results at the university speak for themselves. Zero clogging.

Zero maintenance,” Collins explains.

In addition to places such as universities, hospitals, and convention centers, tough durable pumps are also essential in prisons and other correctional facilities.

A sewage holding tank, which receives

raw sewage from the Morgan County Correctional Complex (MCCX) in Tennessee, needed a reliable solution to handle the various debris in the prison’s effluent. A rugged and highly effective ejector system designed and manufactured by Landia was selected to effectively mix and aerate the holding tank. Landia’s chopper pumps, equipped with a Venturi nozzle, which form part of the propeller-free AirJet aeration system, have to deal with debris from a population equivalent of around 3,200, comprising around 2,500 inmates and over 700 employees at the complex, which completed a major expansion in 2009.

Danny Phillips, maintenance and pre-treatment coordinator for the City of Wartburg’s Municipal Wastewater says: “Landia’s AirJet and chopper pumps are good dependable equipment, which we have no problems with.

And importantly, from day one, we’ve also had great customer service from Landia who are always ready to help us achieve the best results. This definitely isn’t a company that just walks away after they’ve made a sale.”

Any trash that manages to bypass the screens at MCCX is swiftly dealt with in the holding tank by Landia’s innovative knife system, which prevents any large solids from entering the chopper pump, whilst a specially designed pump volute and impeller protects the mechanical seal from rags. z For more information:

This article was written by Chris French, an independent writer for Landia.

Visit: www.landiainc.com

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23

The Yin and Yang

PUMPS

With the right choice of vacuum pump, significant savings in cost of ownership and maintenance can be realised across industries It is estimated that on average there may be one rough vacuum pump for every three compressors installed on a production site. However, in many cases they can be found operating at minimum performance levels in remote areas, which represents an uneconomic burden in terms of energy consumption.

This is ironic considering that state-ofthe-art air compressors are often found in the very same working environments, operating far more efficiently and located at the actual point of use.

Realising such findings, enlightened plant operators are now warming to the idea that having both compressors and vacuum pumps supplied and serviced by a single air movement specialist makes practical sense. In addition, the technical similarities between rotary screw compressors and oil-sealed rough vacuum pumps is leading more companies to view these two air movement solutions together as a “Yin and Yang” synergy.

In practice, this approach confers the benefits of improved operational

efficiency, increased uptime and system integrity, plus the reward of long-term energy savings.

For this reason, the air movement industry has focussed its efforts in recent years on developing innovative vacuum pump systems to the same levels of quality and reliability as those of the compressors. The success of this endeavour is clearly demonstrated in the latest generation of oil-sealed rough vacuum pumps, which have evolved to share an air movement synergy with compressors – a breakthrough that is not far short of a technical revolution in comparison to traditional equipment principles and practices.

These vacuum pumps are designed from the outset to consistently help production plants become more efficient by lowering the cost of ownership, increasing sustainable productivity, and enhancing final product quality.

For a start, efficient, on-site vacuum in a nominal displacement range of up to 900m3/h can now be produced by oil-sealed rotary screw systems that

incorporate two screw elements rotating at slow speeds, enabling the pump to run at sound levels as low as 51dB(A). Such silent operation allows installation close to the point of use with the added benefit of minimum pipework connections and a corresponding reduction in pressure drop energy losses. As an added energy-saving bonus, there are facilities for process heat recovery from individual pump units.

With the latest types of oil-sealed rough vacuum pumps incorporating variable speed drive (VSD) technology, it is also now possible for users to precisely adapt their vacuum generation requirements to match the demands of their process, leading to a dramatic reduction in total cost of ownership.

In general terms, there is also close parallel between the size and rating of vacuum pump drive motors and those of screw compressors. A distinct advantage of this is that such units fall within the boundaries of the British Compressed Air Society’s (BCAS) uniformity of energy reporting initiative – a yardstick which does not apply to other types of vacuum drive systems. The commonality of motors, drive trains, and components argues strongly in favour of maintenance programmes designed to cope equally effectively with compressors and vacuum pumps from the same manufacturer and service provider.

Rough vacuum pumps are also used in a number of applications relating to the handling of fluids, such as de-gassing and de-aeration of oil for transformers and saltwater in oil drilling applications. They are further used for distilling, drying, and cooling in applications including pipeline drying.

Working principle of screw technology vacuum pumps

The GHS VSD+ vacuum pump from Atlas Copco

24

As the screw element rotors turn in a vacuum pump, air is drawn into the rotor housing through the inlet port.

Air is then trapped as the inlet port is closed off and, as rotation continues, FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016

PUMPS the air is conveyed to the discharge side and forced out of the discharge port. Oil is present within the twin screw stage to lubricate, seal, and cool the wetted parts. This oil is separated from the air within an oil mist separator before being discharged to the atmosphere.

The compression cycle of a rotary vacuum pump is a continuous process and is therefore relatively pulsation free.

When the vacuum pump is delivering performance greater than that required by the process application, significant energy savings can be achieved. With other rough vacuum pump technologies, this excess capacity is normally wasted by “bleeding off” or running at a slightly higher vacuum level than is needed.

A screw type vacuum pump saves energy in falling demand conditions by progressively lowering the pressure level at the pump inlet to below that experienced at the process. This procedure continues automatically without the need to adjust machine settings. It also suppresses unnecessary stops/starts whilst catering for continuous fluctuations in demand, thereby minimising wear. The overall result is longer equipment life and reduced maintenance requirements.

Case study The principle is best illustrated by a case study involving Polestar, one of Europe’s largest and independent printing companies, which produces 2.5 million high quality catalogues, magazines, brochures, and supplements every 24 hours from its £100 million (€125.5m), purpose-built production plant.

Ensuring reliability of performance and harnessing advanced technology has always been key to the company’s success. A vacuum system plays an essential role within the transfer of work from the presses to the print finishing and bindery operations. Thus, when confronted with the need for major repairs to three existing conventional vacuum pumps, it made sense to reassess the units’ combined operation to establish the potential savings that could be achieved by installing the most advanced, energy efficient replacement.

Already a long-term user of Atlas Copco’s fixed-speed and VSD rotary screw compressor solutions, pipework, and maintenance services, the company recognised the clear synergies between its compressed air installation and its vacuum generation needs. It was

Europe’s largest independent printing company, Sheffield-based Polestar, expects to reduce its annual energy bill with vacuum pumps

a logical step to trial and install one of Atlas Copco’s new generation of intelligent, oil-sealed, plug-and-play, rotary screw vacuum pumps. These are designed from the outset to deliver peak performance at the required pressure while achieving energy savings of up to 50% compared with conventional oil-sealed and dry vane types of unit. The

When the vacuum pump is delivering performance greater than that required by the process application, significant energy savings can be achieved company’s three original pumps ran at approximately 20kW an hour. The single GHS VSD+ pump that replaced them was a 15kW unit that operates close to 20% load – just 4kW. On an annual 8,000 hours operation, the estimated energy savings are in the region of £10,000.

trends, establishing how well a system is performing, and installing energyefficient solutions where needed.

This cost-saving approach applies equally well to the new generation of rotary screw vacuum pumps.

Applying simple non-intrusive air audit data logging techniques to vacuum pump systems can help establish a true indication of a system’s air use and, ultimately, help to identify any wastage factors such as leakage and pressure drops. These monitoring techniques have been applied to a number of diverse applications throughout industry and as a result of implementing these energy-efficient measures, it is not uncommon to realise operating cost savings of as much as 40%.

It is clear that by looking at all air movement demands collectively, whether for compressed air or vacuum applications, plant operators can achieve considerable improvement in terms of cost and energy-efficiency, plant uptime, and system integrity. What is more, the rapid advance in energy-saving technologies promises even greater productivity benefits for the future. z

Monitoring, measuring, and management Most compressed air users would agree that to get the best return from their capital investment, the monitoring, measuring, and management of compressor installations is essential if optimum control, improved productivity, and energy efficiency is to be achieved.

Conducting energy audits is seen as the definitive approach to identifying

For more information:

This article was written by Mark Handler, vacuum sales manager for South UK at Atlas Copco. Visit: www.atlascopco.com/vacuum

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016 25

A combined effort

PUMPS

When a Texan city lost an essential wastewater pump station, a group of companies rose to the challenge of designing and supplying a new station in just three weeks

The 90ft wide and 30ft deep hole was just a short distance from Brookshire’s store

26

As storms and torrential rain hit Granbury, Texas, back on Sunday 10 May, 2015, what the city’s residents were not expecting to find as the rain subsided the following morning was a large sinkhole in the lakeside parking lot outside Brookshire’s supermarket. Measuring over 90ft wide and 30ft deep, what was initially thought to be a sinkhole turned out to be collapsed earth under a section the parking lot, resulting from the ground becoming saturated. This was caused after an old 7ft diameter storm drain had collapsed following several inches of rain falling in a very short space of time. This was accompanied by a landslip as the ground was washed away down the adjacent hillside.

The collapse of the buried storm culvert was due to water building up and then leaking, literally washing away the earth supporting the city’s No.4 wastewater/

effluent lift station and creating the large crater. Early estimates put the potential repair cost to the city in the region of $500,000 (€440,257). Such was the damage to the underground wastewater pipelines and effluent lift station, coupled with the potential danger to the public, Granbury City Council declared it a local disaster. Their immediate action was to seal off the area and bring in specialist engineering crews to stop water flowing from the broken pipes into the nearby Lake Granbury. The swift action in rerouting the water flow away from the area, using temporary pumps and pipelines, enabled engineers to start shoring up and stabilising the damage on the following Monday.

Starting anew Having successfully eliminated the possibility of wastewater and effluent flowing into Lake Granbury, the pressing concern was to assess the damage and formulate a programme to replace the damaged lift station. Clearly a new one would not only have to stand up to future floods and storms, but employ pumping technology that would provide the best solution for handling wastewater and effluent in a safe and environmentally acceptable manner.

With this being a highly specialised area of environmental engineering, Granbury City Council called on the resources of Abilene-based Enprotec/Hibbs & Todd (eHT), with whom it had worked on several projects over a number of years, and Pump Solutions, Dallas/Fort Worth. Scott D. Hay, VP at eHT, takes up the story.

“This particular area within the City of Granbury is not prone to flooding and this disaster only came about because the old, deep underground drain failed,” relates Hay. “When our local office was called in and visited the site, it became clear to us that this was not really a sinkhole.”

Hay continues: “Looking at the deed records for the area when it was developed in the 1960’s, the natural surface water flow was into the nearby Lake Granbury. The drainage system constructed at the time comprised an 84” corrugated metal drainpipe buried

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PUMPS place in time frames that I had never experienced before,” continues Hay. “A major part of this was Pumps Solutions’ ability to deliver two KSB KRT-F submersible pumps, along with the wet well made by US Composite Pipe, in a very short space of time.

Having previous experience with both companies, it was an excellent choice to work with them on this project. US Composite Pipe offers a steel reinforced, polymer aggregate mix wet well that gives the robustness of concrete without it having to be coated for additional corrosion resistance. Whilst fibreglass wet wells are popular because of price, they are not as robust as concrete wet wells. Pump Solutions delivered the wet well structure and pumps in a remarkably short space of time.”

Pump Solutions worked closely with KSB USA to identify the right pumps and types of impellers for the job. The

The replacement lift station is full working order

around 50ft deep, and over the years this had been added to and modified.

It served its purpose very well, but when we undertook a close inspection this revealed that there was corrosion in certain areas and many joints had opened up. Thus, when the storm surge hit and water built up, the water escaped through these weak spots. The disaster was compounded by the collapse of the No.4 wastewater/effluent lift station.

This had been built, unknowingly, over the top of the drain some 20ft or more below, so when the water leaked out it turned the ground-fill in to quicksand, resulting in the lift station collapsing.”

The original lift station was a duplex unit containing pumps sized to handle flows prevailing at the time of its construction in the 1970’s. “The city took the lead in stopping up all the water and sewage lines and bringing in a by-pass pump at the start of the emergency. It was a rapid and successful response on behalf of the city. Our Granbury City office was then called to the site to get a handle on the environmental issues and stabilise the situation for the long term,” says Hay. Rebuilding the pump station It was only when eHT commenced working on the site that more information about the original lift station was forthcoming. A major issue was that the installation was pumping into a 12” force main and that the pumps did not come even close to providing adequate

preferred design of impeller was a vortex impeller specified by Hay. In his opinion, the vortex was the best type for the application, even though there had never been a problem with grit, solids, or ragging. Being such a high profile project, Pumps Solutions and eHT wanted to put in the best possible option for current and future demands on the system. In fact, such was the speed of the project no actual specification was developed. The sole objective was to get the pump station up and running within the city’s exacting time frame.

KSB Amarex KRT-F submersible pump employs a vortex impeller

velocity to maintain a flow that would scour and clean the main to prevent it from being plugged by waste and solids.

The prime concern related to the integrity of the force main, particularly in respect as to whether it would it be compromised in its ability to perform a full 12” flow.

As a result, a decision was made to address this issue by installing new pumps capable of delivering an increased flow rate at new head conditions.

Although the temporary pumping system was operating effectively, Granbury City Council recognised the urgency in getting a permanent lift pump station up and running. Having settled on a course of action, eHT was given a brief that would require the company deliver a fully operational lift station within a three-week time frame.

“I saw things happening that took

And then, a problem Pump Solutions was the company that Scott Hay turned to as both companies had a well-established working relationship on wastewater and water supply projects. “When we got the call from eHT, we visited the site to see what was required and asked to come up with a plan,” explains Charles Norman, Pumps Solutions. “Because of the time frame, we had a lot of hoops to jump through.

Our solution was based on the existing conditions and the technical brief given in respect to flow, hydraulic duty points, and head, and it was our job to deliver a lift station complete with pumps, precast wet well with access cover, and the necessary control panels for the station.”

The pumps that were finally selected were two 24hp KSB KRT-F models running at 1160rpm, with a design point of 975 US gpm at 30ft TDH for a velocity of 3ft/sec and fitted with 105/8” (270mm) diameter

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016 27

PUMPS Charles Norman of pump Solutions discusses the controls for the lift station with a representative from the City of Granbury

vortex impellers. As a major distributor of KSB’s pumps, Pump Solutions has ready access to the pump manufacturer’s stocks of pumps and components in the US. Also, Pump Solutions has the capability to meet most requirements from its own stock-holding resources in Texas. However, the job required two pumpsets, which were non-standard stock items. Coupled with the hydraulic requirements and the specification of vortex impellers, Pump Solutions approached KSB USA, but the best lead time that they could offer for new pumps to meet these specifications was 12 weeks.

“The city needed the entire pump station solution delivered in just three weeks,” explains Norman. “Having to source the vortex impeller pumps, wet well, piping, wet well access hatch, and lift station control panels was a very tall order. Normally a lift station of this size and specification would take up to 12-14 weeks to complete. The advantage of working with KSB is that they have wet well pumps where the impellers can be swapped out. Their inventory revealed two K-type multi-vane impeller pumps in their warehouse, which we could swap to F-type vortex impellers. What’s more, the hydraulics and motors were a good fit for the job, so we had a potential solution.”

There was, however, another challenge.

The vortex impellers in stock were of the wrong dimensions, so Norman had to start calling other KSB distributors around the US to see if any of them had impellers in stock. Unfortunately, he drew a blank, but another solution was proposed by KSB’s application engineers. This was to use one of their European castings suppliers to manufacture two new impellers and have them air-freighted to KSB’s plant in Henrico, Virginia, for pump assembling and testing. The castings were made and air-freighted 28

from Europe in two weeks, giving KSB one week to do the assembly and testing.

Securing the rest Having solved this challenge, there was also the matter of sourcing the wet well access hatch and the control panels.

Access hatches must be dimensioned for the actual wet well, so they have to be purpose-made, a process that can take up to at least four weeks.

Luckily for Pump Solutions, its regular hatch supplier, US Fabrications in Florida, had one unit of the right dimensions left over from another project. This was shipped to the pre-casting plant making the wet well and cast in place.

The final element was getting the control panels manufactured by Quality Controls & Integration in New Prague, Minnesota, and supplied to site, a process that normally takes 6-8 weeks. “We wanted to give Granbury true state-ofthe-art controls for the lift station,” says Norman. “Our supplier knew exactly what we wanted, designing a touch screen panel that enables easy and rapid data acquisition. Linked to a submersible transducer in the wet well, this monitors the water level in the wet well, raises

alarms to indicate any changes taking place, monitors pump performance, and delivers flow trend flow charts so that city engineers can see what is going on in real time and historically.”

So how was all this achieved by Pumps Solutions? “Through our branches in Dallas, Austin, and Houston, we have established a supplier base that sees great benefits in collaboration,” says Norman.

“A collective effort by all parties is the only way we achieved success. As a distributor we can only satisfy customers’ needs with the help of others around us.

It starts with the system being designed by quality and experienced engineers.

And then it’s up to our manufacturer to produce a product within the required time frame. Without all parties coming together as a team, we fail.”

Summary The stability of the new lift station had to be given major consideration, and for this reason it was not built on the original site. A decision was made to move the lift station further away from the area were the land collapsed and also away from the underground drain. New ground works had to be put in place, with some rerouting of the pipes and associated infrastructure.

This disaster has had a positive outcome for the City of Granbury, in that it now has a robust and efficient lift station that has increased pumping capacity to accommodate future growth, and ensures the safe transfer of wastewater and effluent away from the Brookshire’s parking lot and Lake Granbury. z

For more information:

This article was written by Bryan Orchard, an independent international journalist working in the areas of pump and valve technologies, for KSB USA. Visit: www.ksb.com

The new pump station occupies a new site on the edge of the parking lot

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PUMPS

The venerable veteran A UK water pump station has been modernised without sacrificing its traditional charm

Thames Water is the UK’s largest water and wastewater services company, supplying around 2.6 billion litres of tap water to more than nine million people across London and the Thames Valley area. One of Thames Water’s biggest abstraction facilities is the Littleton Raw Water Pump Station (RWPS) in Surrey, UK. Built between 1923 and 1925, the station preserves much of its original character.

In an initiative to make Littleton the most cost-effective and reliable river abstraction system along the Thames, while retaining the site’s authentic personality, Thames Water collaborated with its longstanding partner, the pump management team of Boulting Group (Boulting).

The Littleton pumping station was originally fitted with four 900mm discharge horizontal double suction axially split case pumps. Each individual pump had a capacity of 340 million litres per day.

In the 1950s, three pumps were modified to electric motor drives and have been operating using this arrangement since.

The pump station is responsible for maintaining the water supply to one of the largest raw water reservoirs in the UK, providing fresh water to London and some neighbouring counties. It covers 707 acres and lies 13m above the surrounding area.

Despite its successful history and charming character, the Littleton RWPS wasn’t operating at optimum efficiency.

Improvements could be made to reduce loss of pump priming, minimise cavitation, simplify start-up, maintenance, and control procedures, reduce energy usage, and therefore, operational costs.

Requirements After four years of successful projects with Boulting, Thames Water invited the company to propose an upgrade to the Littleton RWPS, which would increase the performance of the site while also making it more flexible, reliable, and

Littleton Pump Station – pump room (1925)

energy efficient. Thames Water was also keen to increase the average capacity from 400 to 750 million litres per day.

In addition, Thames Water wanted to implement an automated system with remote control function, which would allow a faster and more efficient pump start-up procedure, while also making monitoring easier. In the existing system, operators had to go to the site and work for three to four hours to start up a pump, making the operation time-consuming and costly.

The final requirement was providing dual electrical power supply from the National Grid and up to 1.5MW of power supply from a photovoltaic (PV) solar power system located in an adjacent field.

Solution To address these requirements, Boulting completed a holistic, objective site testing and evaluation process of the entire system, including Front End Engineering and Design (FEED). This resulted in a set of recommendations, including the upgrade of assets like switchgear, motors, drives, and control systems.

Although the Boulting report had no further contractual obligations attached and Thames Water was free to commission a different contractor to implement any improvements, the deep-rooted collaboration with pump management and previous successful projects prompted the company to assign the engineering, design, procurement, and implementation

contracts to the Boulting Group.

In addition to fulfilling the client requirements, an unexpected benefit of working with Boulting was the pump management teams’ enthusiasm for keeping the pump station’s original aesthetics and character. After a close collaboration with Thames Water, Boulting slightly altered the initial scope of the project to minimise the loss of original aesthetics and to preserve the pump room character.

Technical overhaul The original impellers were limited in efficiency to around 80%. To improve the hydraulic performance and the priming process, Boulting suggested a pump upgrade, including a complete redesign and manufacture of the pump impellers to help improve the net positive suction head (NPSH) characteristic and pump efficiency. The specific design Boulting created for this project allows an improvement to 87% pump efficiency and increased reliability during start up and operation. Another benefit of the new design was the minimisation of cavitation and its damaging effects on the pump components.

Poor priming also made the old system difficult to manage, time-consuming and expensive. To resolve the issue, Boulting suggested the installation of a new and automated priming system that uses motive air vacuum ejectors and continuous

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PUMPS

Commencement of pump refurbishment

water level monitoring. To further increase priming reliability, the old packed glands were replaced with mechanical seals. This reduced leakage to virtually zero, making the system more reliable and adding an extra 2% to overall system efficiency.

The pump upgrade and refurbishing also meant an improvement in overall energy efficiency. In the new installation, the pumps, motors, drives, and channel level will be automatically controlled to optimise the specific energy consumption (SEC) of the system. Each component will be controlled individually and automated using Boulting’s pump system optimisation (PSOp), installed within SCADA managed programmable logic controllers (PLCs).

The PSOp software was developed by Boulting. It is able to continuously monitor and analyse the pump system, taking into account the known characteristics of each component in terms of performance. The system automatically identifies the speed the pump needs to operate at to achieve optimum efficiency. It also automatically

Bottom half of pump casing prior to refurbishment

detects how many pumps need to be running at any given time to ensure the lowest specific energy consumption.

In addition, the remote control feature of the PSOp software meant even further cost savings for the Littleton system.

Whereas in the past operators had to go on-site and manually start the pumps – a time-consuming and often unreliable operation – the new system reduces pump-start up time by up to 96%.

Another interesting feature of this project was the need to integrate dual power supply from the National Grid as well as a separate solar power photovoltaic system. A high voltage switchboard that enables the pump station to use PV power when available and supplement it with grid power when necessary was installed at the site.

designed pump room, created in the mid 1920s. To preserve the personality and historical character of the space, Boulting suggested changing the layout of the system. This meant removing some equipment installed in the 1950s and several add-on pieces such as air ducts, as well as installing modern inverters, panels, transformers, and a control system in an adjacent room.

The original pumps are connected to new high-performance motors and gearboxes, close to the oldest static steam-driven pump, which will be kept as a museum piece. After the most recent upgrade, the pump room will actually look more like the 1920s original, although the system will see a boost in reliability, flexibility, and energy efficiency.

Conclusion

Aesthetic considerations The unique character of the Littleton pump station comes from the beautifully

Thames Water originally estimated the upgrade would take at least two years, but by working closely with Boulting, the project is expected to take only half that time, including the design, delivery, and installation of the new system.

By improving efficiency, reliability, and performance, and by integrating a renewable energy source, the new system will be highly energy-efficient.

The upgrade aims to make the Littleton abstraction station one of the most modern and innovative in the UK. The project will provide significant and sustainable benefits to Thames Water.

The annual energy savings resulting from this project are predicted to exceed 4.9 million kWh with an energy cost reduction close to £500,000 (€708,500). z For more information:

3D modelling of the new impeller

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This article was written by Brian Conway, the pump management director at Boulting Technology. Visit: www.boultingtechnology.co.uk

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The good ol’ boy

PUMPS

A Finnish paper mill needed its vacuum pump repaired after 45 years, but the old workhorse’s good overall condition came as a surprise Within the papermaking industry, removing water at the earliest stage in the process speeds up the formation of a hard, strong, consistent sheet whilst also reducing web breaks and water removal costs. This is typically performed by low vacuum fans. However, further along the production line there are stages where higher vacuum levels are required to remove water and assist in the drying process. These duties are typically performed by Nash liquid ring pumps as they are suited to adjusting the vacuum levels to optimise water removal and deliver maximum efficiency.

The papermaking process places considerable demands on the liquid ring pumps as they are continuously operating, which is why they have to be reliable, efficient, and hardworking. Of all the Nash liquid ring pumps operating in paper mills, it is the CL series that is most widely-used. So when AxFlow Finland took delivery at its Kotka workshop in October 2015 of a Nash CL pump from a paper mill in northern Finland, it came as no surprise to learn that the pump had been operating for over 45 years.

“The pump was delivered to our workshop as a complete unit, and due to its size, a crane was used to transfer the pump from its transporter into our workshop,” says Sami Salonen, sales engineer at Axflow Finland. “The first task was to strip the pump down in order to determine the cause of failure. This was not a straightforward task, taking around five days to complete the job and record details of the state of all the components.

Because of its age and long operating life, many of the parts had fused together so patience had to be exercised.”

The repair process Once the pump had been opened up, it became clear that the bearing rollers at one end of the shaft had failed due to overheating, most probably down to a lack of lubrication. The bearings at the other end were in a reasonable condition as there was sufficient lubricant in the gear box. In order to remove the

Stripping down the Nash pump at the Kotka plant

The roller bearings were badly worn as a result of overheating

damaged bearing rollers, the complete bearing housing had to be cut free from the end plate and a replacement bearing housing installed. The condition of the original end plate was a cause for concern and beyond repair, so the customer supplied a replacement along with the pump, and to bring this up to specification it was cleaned and given a wear resistant coating.

Whilst there was little sign of wear to many of the components, due to the non-aggressive nature of the media being pumped, a programme of refurbishing and cleaning the pump was undertaken prior to the installation of the new bearing rollers and end plate.

“The exacting process of recoding the condition of components during strip down enabled AxFlow’s engineers to identify where refurbishment work would be required and also highlight to the customer the remaining lifespan of components for maintenance purposes,” comments Salonen. “It is a procedure that we undertake on all repair jobs. In the case of this pump, failure was down to the absence of oil in the roller bearings, so the pump had performed extremely well over the many years that it had been in service.”

Being able to take on such a challenging project is attributable to AxFlow Finland’s knowledge of Nash liquid ring vacuum pumps and its engineering skill sets. “Nash places considerable emphasis on the quality of its pumps and demands that its suppliers are suitably qualified to undertake repair and maintenance of

its products,” says Salonen. “AxFlow has extensive engineering facilities together with the necessary qualifications and approvals from Nash to undertake this type of work. For this particular job we had to develop specialist tools.”

A key service that AxFlow Finland offers to Nash pump users is condition monitoring. The company’s employees go to the plant and attach a purposedesigned flange to the pump inlet ports.

Once the pump is rotating, they can measure how much air is coming through the holes in order to measure vacuum levels. Knowing the area of the holes enables the engineer to determine how much air can be sucked. With these results, a pump curve can be created so the actual performance level can be compared against the designed performance level. Alongside this service is the provision of hydroscopic inspection, which reveals the condition of components. Whilst this has many benefits, a capacity test will illustrate the true operating condition of the pump.

Having invested in an expanded service and repair centre in Kotka in late 2015, AxFlow now has the heavy lifting, machining, and cutting edge engineering resources that enable the company to provide services not just for the ranges of pumps within its own portfolio, but for many other types and brands. z

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For more information:

This article was written by Bryan Orchard, an independent international journalist working in the areas of pump and valve technologies, for Axflow Finland. Visit: www.axflow.fi

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FLOWMETERS

Ultrasonic on the rise

Custody transfer applications drive the growth in the ultrasonic flowmeter market The history of ultrasonic flowmeters goes back to the early 1960s. Ultrasonic flowmeters were first introduced for industrial use in 1963 by Tokyo Keiki in Japan. In 1972, Controlotron (now part of Siemens) became the first US manufacturer to market ultrasonic flowmeters in the US. In the late 1970s and early 1980s, both Panametrics (now part of GE Measurement) and Ultraflux experimented with the use of ultrasonic flowmeters to measure gas flow. In those early days, ultrasonic flowmeters were not well understood, and were sometimes misapplied. They began to achieve wider acceptance in the 1990s, as end-users learned more about how they work. Since the 1990s, there has been strong growth in the ultrasonic flowmeter market.

Transit time and Doppler There are two main types of ultrasonic flowmeters, namely transit time and Doppler. A transit time ultrasonic flowmeter has both a sender and a receiver. Using transducers, the flowmeter sends two ultrasonic signals across a pipe at an angle, one with the flow and one against the flow. The meter then measures the “transit time” of each signal. When the ultrasonic signal travels with the flow, it travels faster than when it travels against the flow. The difference between the two transit times is proportional to flowrate.

Doppler flowmeters also send an

ultrasonic signal across a pipe, but the difference is that they are used in fluids containing particles. They rely on having the signal deflected by particles in the flowstream, which are traveling at the same speed as the flow. As the signal passes through the flowstream, its frequency shifts in proportion to the mean velocity of the fluid. A receiver detects the reflected signal and determines its frequency. The meter calculates flow by comparing the generated frequencies and the detected frequencies. Doppler ultrasonic flowmeters are used with dirty liquids or slurries, and they are not used to measure gas flow.

Mounting types There are three different mounting types available for ultrasonic flowmeters: • Clamp-on • Spoolpiece • Insertion Many people associate ultrasonic meters with the clamp-on style. Clamp-on ultrasonic flowmeters have transducers that are clamped onto the outside of the pipe. Some clamp-on meters are portable and others are fixed, with the fixed ones also called dedicated meters. Clamp-on ultrasonic meters have the advantage that they can easily be moved from one location to another. They can also be mounted without cutting into the pipe.

One disadvantage is that the pipe wall In 1999, Colorado Engineering Experimental Station opened its calibration facility in Iowa

32

can attenuate the signal, depending on its material and thickness. As a result, clamp-on meters are generally not as accurate as spoolpiece meters.

Spoolpiece ultrasonic flowmeters consist of a section of pipe with the transducers mounted in the pipe section.

When spoolpiece meters are mounted, they replace a section of pipe, and they come in either wafer or flanged models. If the transducers are in contact with the fluid, they are referred to as “wetted”. Spoolpiece meters are used where high accuracy is required, such as in custody transfer applications.

Insertion ultrasonic flowmeters are used to measure large pipes. Insertion meters are also referred to as “hot tap” or “cold tap” meters. Their general applications include measuring flare gas and flue gas, and also for measuring the flow of liquids in large pipes. An increasing need to measure the amount of greenhouse gases being emitted into the air has led to growth in the insertion flowmeter market. For this application, they compete with thermal flowmeters and differential pressure flowmeters using averaging Pitot tubes.

Multipath flowmeters Suppliers have developed multipath spoolpiece meters that use three or more pairs of transducers and measure flow in more than one location. Measuring flow in multiple locations within the flowstream results in higher accuracy. While four-, five-, and six-path ultrasonic meters are the most common among the multipath types, some suppliers have developed eight-path and even 18-path ultrasonic meters. Multipath meters have been particularly important in the use of transit time meters to measure gas flow.

Probably the single most important factor in the recent growth of ultrasonic flowmeters has been the rapid growth in the market for multipath ultrasonic meters for custody transfer of natural gas.

The initial surge in growth began in 1995, when Groupe Europeen de Recherches GaziSres (GERG) published Technical

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FLOWMETERS Monograph 8 on multipath ultrasonic flowmeters. This technical document laid out criteria for using multipath ultrasonic meters for custody transfer of natural gas. Its publication boosted the sales of multipath ultrasonic flowmeters for natural gas, especially in Europe.

After the GERG document was published in Europe, ultrasonic suppliers worked with the American Gas Association (AGA) to obtain approval of a similar document in the US. As a result, AGA-9 was published in June 1998. AGA-9 lays out criteria for buyers and sellers of natural gas to follow when using ultrasonic flowmeters for custody transfer of natural gas applications.

The publication of AGA-9 also boosted sales of multipath ultrasonic flowmeters for natural gas, especially in the US. Natural gas is not the only area where multipath ultrasonic meters are being used. In 1997, Krohne introduced a five-path transit time meter for liquid applications. Just as is the case for multipath meters for measuring the flow of natural gas, the five-path meter provides greater accuracy than single path meters.

This meter is being used for custody transfer of liquids. In 2003, Krohne followed up with its Altosonic III. The American Petroleum Institute (API) has approved a draft standard for the use of ultrasonic flowmeters for custody transfer of liquids.

Calibration facilities One of the barriers to the use of ultrasonic flowmeters to measure natural gas flow has been the issue of meter calibration.

Until 1999, there was no easily available calibration facility in the US. Users wishing to have their meters calibrated had to in many cases send them to Europe. In 1999, Colorado Engineering Experimental Station (CEES) opened its calibration facility in Iowa. This facility can calibrate large meters in the 30” to 36” range, as well as smaller meters.

Users in the US and Canada can now have their meters calibrated at CEES in Iowa, avoiding the cost and delay of sending their meters to Europe.

Another high pressure natural gas calibration facility called TransCanada Calibrations opened in spring 2000 in Winnipeg, Manitoba, Canada. This facility services the Canadian market, although it is also convenient to many users in the northern US. Southwest Research Institute (SWRI) in Austin, Texas, is another facility that is capable of performing

Van Swinden Laboratory tests ultrasonic flowmeters for traceability

calibrations, although they cannot easily calibrate ultrasonic flowmeters larger than those in the 16” to 20” range.

In 2010, a flow calibration facility called Euroloop opened in Rotterdam, Netherlands. The funding for Euroloop came from a number of flowmeter suppliers, including Krohne. The facility issued its first flowmeter certificate in March 2011 to Elster-Instromet. Euroloop is operated by NMi, the Netherlands Metrological Institute, while Van Swinden Laboratory (VSL) handles traceability. Euroloop is designed for the testing and calibration of industrial oil and gas flowmeters.

Improvements in transit time technology Many technological improvements have been made in ultrasonic flowmeters in the past 20 years. Because of improvements in electronic processing technology, transit time meters are better able to handle liquids with some impurities. This has enabled transit time flowmeters to be used for applications that previously required Doppler flowmeters. These improvements have also increased the accuracy of ultrasonic meters, which has led to broader use of these meters in a wider variety of conditions.

The use of Doppler meters has declined with the improvements in transit time technology. Doppler appears to be almost exclusively a clamp-on technology, although some are used as insertion meters. The difficulties with clamp-on technology are well known.

In addition to uncertainties due to the signal passing through a pipe wall,

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clamp-on meters have to be installed at the proper location to work correctly.

Build-up in the pipe wall can affect the internal pipe diameter, which can also lead to measurement uncertainty.

Doppler technology is inherently less accurate than transit time technology.

Given all these considerations, it is not surprising that transit time meters have impinged on Doppler meters.

The future of ultrasonic meters Ultrasonic flowmeters have a bright future, especially for gas flow measurement. They compete with turbine and differential pressure meters in the fast-growing market for measuring custody transfer of natural gas in pipelines. Many of these pipelines exceed 20” in diameter, and multipath ultrasonic meters meet the high accuracy specifications required for these applications. Unlike differential pressure and turbine meters, they are non-intrusive and they can measure a wide range of flowrates. Natural gas is increasingly seen as a cleaner alternative to coal and to petroleum liquids, and applications for natural gas flow measurement are continuing to grow. Ultrasonic meters will continue to benefit from this long-term trend towards the use of natural gas. z

For more information:

This article was written by Jesse Yoder, Ph.D., president of Flow Research and a leading expert on flowmeters. Visit: www.flowresearch.com and www.flowPD.com

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A novel approach

FLOWMETERS

A new kind of ultrasonic flowmeter enables accurate measurement in low flow applications Across the industrialised world there is an increase in demand for liquid flow measurement systems operating at low flow rates. The range of applications that might benefit from such systems is wide, including offshore, industrial, medical, food, beverage, pharmaceutical, and laboratories. The requirements on flowmeters to fulfil these applications are also becoming more demanding. An ideal flowmeter might have through flow design with minimum pressure drop and improved accuracy, as well as offering operation at higher pressures/temperatures and across wide flow ranges with greater accuracy.

A meter that can be easily cleaned either chemically or with a “pig” and be able to operate over a wide range of Reynolds numbers would be a great advantage.

Typically, the three most popular current technologies for such flowmeters are electromagnetic, Coriolis, and ultrasonic.

Electromagnetic meters are restricted to conductive fluids and Coriolis meters are expensive, which leaves ultrasonic as being the most widely viable meter type for these applications. Of the two ultrasonic technologies, Doppler shift and time-of-flight (TOF), the latter offers the best performance over the widest range of operating conditions.

TOF ultrasonic flowmeters are generally suitable for larger pipe sizes but they can also be used in smaller tubes.

Recently, a novel, small bore ultrasonic flowmeter which operates in pipe diameters where traditional meters of this type stop working was introduced.

Initially, the meter was developed as a replacement for small turbine meters in laboratory, industrial, and beverage applications. The achieved performance has far exceeded expectations, making the meter suitable for a far wider range of applications. The patented technological approach has enabled a wide variety of different flow measurement, dosing, and control applications to be addressed.

Using the same electronics with an appropriately sized flow tube, it is possible for the meter to monitor a range of flows from 3m3/h to 0.12l/h with an accuracy 34

of better than ±1% over a flow range of exceeding 200 to 1 when used with pipe sizes as small as 1mm in diameter.

The described ultrasonic flowmeter is capable of providing an update rate of 0.05s and is therefore suitable also for batching type applications.

Figure 1: Operating principle of a diametrical beam ultrasonic flowmeter

Small bore transit time ultrasonic flow meters Ultrasonic flowmeters make use of the fact that sound travels at different speeds with and against the fluid movement. This difference in the TOF equates directly to fluid velocity. Traditional TOF ultrasonic flowmeters use one or more diagonal beams across the tube. One beam is used for small pipes and multiple beams in larger conduits to better integrate the velocity profile and give more accurate results. The formula to calculate the upstream and downstream transit times for a single diametric beam has a constant of proportionality, which includes the diameter of the tube. Therefore, as the tubes become smaller, the transit time difference (which equates to fluid velocity) becomes proportionally smaller.

To increase the ultrasonic beam length, multiple reflections are sometimes used, but each reflection attenuates the flow and thus reduces signal integrity. Axial beams that have a fixed geometry and therefore a fixed flight length are also used, but this is independent of tube diameter. This fixed length is the primary distance and the diameter of the conduit becomes part of the meter constant.

Diametrical meters Figure 1 shows the operation of a diametrical beam ultrasonic flowmeter in which the cross-section of the channel is circular. An ultrasonic wave is transmitted from transducer 1 and received by transducer 2 to measure the transit time upstream. A second ultrasonic wave is transmitted from transducer 2 and received by transducer 1 to measure the transit time downstream.

The transit time difference between the downstream and upstream waves is given by:

T = T12 - T21 =

2.v.cos .l c2

In this equation ΔT is the difference in the transit times, T12 is the propagation from transducer 1 to transducer 2, T21 is the propagation from transducer 2 c2. T to transducer 1, v = v is the average axial velocity measured θ 2.v.cos .l 2.cosalong .l the beam, T =angle T12 -between T21 = the 2direction of is the c propagation and the pipe axis, and l is the length of the path over which the integration is made and c is the speed of sound in the fluid. Thus:

v=

c2. T 2.cos .l

The average velocity measured along the beam is then used to compute the average velocity across the cross section of the channel and hence the flow rate of the fluid through the channel.

Diametrical ultrasonic flowmeters employing a single beam are known to be sensitive to velocity profile changes, which occur as a consequence of the change in Reynolds number in fully developed flow or by upstream flow disturbances caused by pipework, such as bends or reducers and valves. Multichordal or multi-path flowmeters use the transit time measurements over one or more paths in the cross section of the flowmeter to improve the velocity profile averaging across the whole of the of the cross section of the flow and thus reduce the effects of varying velocity profiles. These are however not appropriate for small diameter pipes.

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016

FLOWMETERS At low flow rates, particularly in small diameter tubes, the transit time differences become difficult to measure.

For such applications, multiple reflections or axial designs are commonly used. In the reflecting methods as shown in figure 2, the ultrasonic beam transits the flow tube several times (typically two or four times) by reflecting the beam off the walls of the flow tube and thus increasing the transit times and the transit time differences. The number of reflections is usually limited to either one or three, since the width of the beam may lead to interference between reflections and reduction in signal strength on each pass.

Figure 2: Multiple reflections in a flow tube

Axial designs as shown in figure 3 are used to decouple the length over which the transit time difference is measured from the diameter of the pipe. The effective length of the flowmeter changes from being the geometric distance between the transducers at high flows to be somewhat shorter at low flow, because of flow creeping round the bend at the exit of the flowmeter. Such a flowmeter cannot be cleaned using a ball-shaped pig and is subject to serious turbulence around the faces of the crystals as the liquid turns the corner.

provides averaging of the velocity profile irrespective of the flow profile. Thus it shows no change in sensitivity as the flow profile changes from laminar to turbulent and is relatively immune to changes in viscosity.

Figure 3a: An alternative ultrasonic arrangement for water metering

Modelling of the flowmeter

into the bore so cleaning with a ball shaped sponge is out of the question.

The novel design

To ensure a robust design, extensive modelling of the flowmeter was undertaken. Such simulations enable the design of the flow tube assembly to be optimised from an ultrasonic point of view and the effects of the drive and receive electronics to be fully analysed.

Figure 5 shows a typical flowmeter configuration. The model is for half the meter length of the flowmeter and it is modelled with radial and axial symmetry.

Figure 6 shows the waves passing down the flow tube and figure 7 shows typical predicted signal on the downstream transducer when the upstream transducer is excited with three cycles of a suitable wave. It can be seen that the actual received signals differ from the predicted waveform but with sufficient similarity to make the simulations relevant and very useful in optimising the design.

Flow measurement specialist Titan Enterprises selected an alternative configuration for its small bore Atrato ultrasonic flowmeter. Figure 4 is a schematic taken from the first conceptual drawings. The transducers are acoustically coupled to the meter and excited in such a way that they oscillate radially, injecting a strong ultrasonic signal at 90° to the fluid motion. The operating frequency is such that the wavelength of the sound in the fluid is substantially less than the pipe diameter, ensuring no reflections around the pipe occur.

Signal processing

Figure 4: Titan Enterprises ultrasonic meter configuration

This configuration ensures that the sound propagates in a â&#x20AC;&#x153;plainâ&#x20AC;? wave axially down the pipe with a central section manufactured in stainless steel or some other suitable material. There is also an attenuating non-plane wave, which is symmetric about the central plane of the transducer assembly. When this wave interacts with an axi-symmetric velocity profile, it provides no contribution to the transit time difference. The plane wave propagating down the flow tube

A low cost signal processing scheme has been developed. The method

Figure7: Predicted received signal

Figure 3: Axial design of an ultrasonic flowmeter

Figure 3a shows a third type of arrangement typically used in ultrasonic water metering, where the ultrasound is transmitted at degrees to the flow and reflected to form a beam axially with the fluid transit. It is then reflected again to a second transducer, which then repeats the process. This type of meter forms turbulence around the flow path, which effectively alters the flight length. It also has protrusions

Figure 5: Model of the flowmeter

Figure 6: Waves travelling down the flow tube

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35

FLOWMETERS

Figure 8: Actual signal received

of driving and receiving used in the flowmeter employs reciprocal action.

This is essentially driving the transducers from and receiving the signal into the same impedance, in this case a low impedance. This approach ensures that the transducers at zero flow have identical receive signals independent of matching of the transducers, coupling, and liquid temperature.

The only requirement for this to work is that the transducers and associated circuitry should be linear and that during reception the transducers do not see any signal generated by themselves since this signal is not reciprocal.

The transducers are thus driven from the output of a low impedance linear amplifier and the signal received from the transducers is received into a low impedance transimpedance amplifier.

The signal is then passed through a band pass filter centred at 200kHz before being input to the microprocessor. Electronic switches in the system change the roles of the transducers from transmitter to receiver and the upstream and downstream transducer are excited sequentially. The data from the signals in both directions is averaged over a number of transmissions and stored.

A novel time measurement algorithm then processes the signals to extract the time difference between them. This signal is then processed to compensate the measurement for the speed of sound in the fluid, which enables the flowmeter to be used with a range of fluids and also to be independent of the speed of sound in the fluid. The electronics are capable of providing the user with a visual indication of flow, a pulse output giving a pulse per 36

unit volume of flow, or a 4-20mA output.

Figure 8 shows a typical performance of a 6mm flowmeter. The calibration shows that the flowmeter is capable of measuring from 0.006l/h to 1.2m3/h, a range of 200:1 well within ±1% of reading.

By changing the bore of the meter to 1mm, flows as low as 0.12l/h have been measured and prototype meters have measured flows as low as 0.015l/hr.

Figure 9 shows the Atrato flow meter assembled with its integral display.

Using this technology Titan Enterprises has provided several bespoke flow metering solutions where other technologies were not practical.

Future developments

it only takes a small amount of flow to result in a significant phase shift at these distances. In this development Titan has identified flows as low as 150μl/min and recorded accuracies of ±1% at 500μl/min. Lower flows will be possible in future with improved algorithms and signal processing.

High pressure units: Titan has also prototyped a high pressure Atrato ultrasonic flowmeter rated at 1.5-90l/h and 1000 bar. The meter performed without complaint and was better than 1% accurate over the whole flow range. This novel design is subject to a patent application.

Medical flowmeters: In 2015, Titan Enterprises licensed its Atrato technology to a leading global medical device company for intravenous injection bolus measurement with a disposable flow element for use in the operating theatre.

Conclusion The new low flow ultrasonic flow metering technology has far exceeded expectations. The original specification was for a simple laboratory meter giving a ±2% device operating over a 20:1 flow range with a 6mm bore. In reality, the technology has enabled development of a whole range of products, which offer significant benefits to applications in offshore, industrial, medical, food, beverage, pharmaceutical, and laboratory markets with lower flow rates, higher temperatures, pressures, and improved performance. z

To provide an indication of the wide scope of this ultrasonic flowmeter technology, below are some future For more information: This article was written by Trevor Forster, developments that Titan Enterprises managing director at Titan Enterprises. is currently investigating.

Visit: www.flowmeters.co.uk Very low flows: Because Atrato technology transmits the ultrasound in a plain wave down the conduit with no reflections, the signal integrity is very strong.

Titan has successfully transmitted signals down one metre of one millimetre bore tubing.

At this length, the thin tube is very difficult to handle, but because the signal is a plain wave it can simply be formed into a 30mm diameter coil, which is then simpler to deal with. It should be noted that Figure 9: Atrato production meter FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016

EVENT PREVIEW

Houston, we have a show ILTA’s annual international operating conference and trade show in Houston, Texas, on 23-25 May brings together thousands of terminal industry professionals to exchange information, identify best practices and find the latest in equipment and technology. But what can you expect to find amongst the dozens of exhibitors? We have gathered here just a few highlights Arflu Arflu is one of the leading manufacturers of industrial valves for the petrochemical, gas, water and desalination, solar, and marine divisions. Arflu offers properly tested, high quality and durability industry valves and seeks to develop technologically efficient products. Arflu’s Technology and Innovation department is responsible for developing new products and revising the current offerings depending on market requirements. Their latest tools for valve design include threedimensional design, 2D machining form drawings, and finite element calculation.

At Tank World 2016, Arflu will be exhibiting its dual expanding plug valve, which has been developed in response to operator concerns and designed to eliminate common problems that occur

during operation. For example, the valve uses a full-size stem packing, and it can also be installed with a special stem packing and an inverted stainless steel trunnion, which completely eliminates body cavities. Arflu valves feature a backseat and the stem packing is accessible from the outside and can easily be changed even under pressure.

Visit Arflu at booth 1123

Arflu’s dual expanding plug valve eliminates common valve issues

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016

Blackmer At this year’s ILTA show, Blackmer, part of PSG, a Dover company, will be featuring its S Series screw pumps. Available with or without external timing gears and bearings, Blackmer ATEX-certified S Series pumps are self-priming doubleended positive displacement pumps that offer high performance in the most 37

EVENT PREVIEW demanding liquid storage terminal applications. Blackmer’s twin and triple screw designs provide complete axial balancing of the rotating screws and their timing technologies eliminate metal-to-metal contact with the pump.

Blackmer will also showcase its ML Series sliding vane pumps, which are wellsuited for liquid terminal operations that require high-capacity product transfer, top or bottom loading/unloading, and blending at the rack. ML Series pumps offer self-priming and high-suction capabilities that enable them to clear tanks of product more effectively and efficiently. ML pumps can handle fluid viscosities from 1 to 108,000cS with flow rates up to 136m3/h and at operating temperatures as high as 206°C. STX Series sliding vane pumps from Blackmer will also be on display in the booth. STX Series transport pumps are a good fit for loading and unloading corrosive and non-corrosive liquids that are not compatible for use with cast iron pumps. These pumps offer the combined characteristics of sustained high-level performance, energy efficiency, trouble-free operation, and low maintenance costs.

Blackmer HD Series reciprocating gas compressors will also be featured at ILTA. HD Series compressors provide quiet, efficient transfer of a wide range of liquefied gases. HD Series compressors have been designed to handle the vapour recovery of gases common in terminal applications.

The vapour recovery aspect of this application captures vapours before they are released in the environment,

allowing terminals to be more environmentally responsible and compliant while ensuring the most complete product transfer possible.

Visit Blackmer at booth 733

FMC Technologies Named by Forbes Magazine as one of the world’s most innovative companies in 2013, FMC Technologies has approximately 17,400 employees and operates 29 production facilities and FMC Technologies’ AccuLoad IV can be used in most service bases in 18 countries. petroleum loading and unloading applications The company produces global measurement solutions by designing, The Smith Meter brand is known worldwide manufacturing, and servicing the precision for its ability to produce reliable, accurate, products and systems used to measure and consistent measurement results. and control the transfer of liquid and gas Similarly, FMC’s Sening brand tank truck hydrocarbons in industrial applications. components and systems are trusted Continuing the company’s long to provide safety and environmental legacy of ensuring customer success with protection, while ensuring accurate over 35 years of experience designing measurement during the transport and electronic preset control systems, FMC transfer of petroleum products. FMC Technologies introduces AccuLoad IV. Technologies also delivers automation, This fourth-generation system features control, and information technology a colour touch screen and advanced throughout the energy supply chain communications for automated control, based on its Fuel-FACS+ family of terminal along with intelligent diagnostics and automation and business systems. a seamless upgrade path. Providing a Visit FMC Technologies at booth 437 robust system used in the majority of petroleum loading and unloading custody Fort Vale transfer applications, the AccuLoad Fort Vale is launching its brand new is one of the market’s leading preset Safeload Loading Arm, the latest addition controllers. With its enhanced features, to its range of products for the petroleum AccuLoad IV provides high accuracy, transfer industry. Unique safety and design reliability, and flexibility by incorporating features include an integral earth system the latest available technologies, making that ensures electrical continuity without it more powerful and responsive. separate wiring, a device to prevent overrotation, and a three-seal dual needle/ dual ball race bearing combination for maximum axial and radial strength and performance. The stainless steel and aluminium construction fitted with specialist high-pressure low-friction seals ensures high corrosion resistance, rugged durability, and enhanced performance.

Offering great installation flexibility, the Safeload Arm can be configured to suit a top or bottom fuel supply and left or right orientation. Separate components or a complete assembly may be supplied and all swivel and pipework flanges have industry-standard drilling patterns for compatibility with existing installations.

Fort Vale will also be exhibiting its complementary range of bottom loading couplers. The Safeload API coupler has become first choice for terminals and remains the only API in the industry At its booth, Blackmer will be showcasing its versatile range of pumps

38

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016

EVENT PREVIEW and optimised to deliver the highest performance. From the advanced safety features to the quick and easy disassembly for fast maintenance, the Lynx coupler is the only one of its kind.

“Lynx will become one of our flagship products,” says Morrow. “Liquip and OPW engineers have really outdone themselves.

This is the only coupler that can be disassembled in less than 30 seconds, handle surge pressures up to 500 psi, and comes with five-year warranty. We can’t wait for customers to experience LYNX.” Visit OPW Engineered Systems at booth 733 Protego Protego offers a comprehensive line of flame arresters, tank vents, and tank accessories that are tailored to meet market demands. The products are installed by industrial users for a wide range of applications, including but not limited to tank farms, industrial and

The new Fort Vale Safeload Loading Arm system will be exhibited at ILTA 2016

with a three-year warranty. Its unique extended latches follow the profile of the truck adaptor, covering over 50% of its circumference. This ensures maximum safety and security of connection and minimises wear to both the latches and the adaptor, which increases the service life of both components.

Visit Fort Vale at booth 740 OPW Engineered Systems OPW Engineered Systems, part of OPW’s Fluid segment within Dover Corp., will announce a new complete terminal equipment offering and its next-generation API coupler technology at this year’s ILTA. OPW’s terminalequipment offering will feature the most complete line of loading arms, API couplers, electronic rack equipment, safety breakaways, railroad and tankcar unloading fittings, and accessories.

“Having all of this as one complete terminal package streamlines the whole spec’ing and ordering process for customers,” says Dave Morrow, director of products for OPW Engineered Systems.

At the show, OPW Engineered Systems will also announce its next-generation API coupler, Lynx, as part of its new terminal package. Every component in the Lynx has been completely redesigned

military applications, chemical and pharmaceutical processing facilities, wastewater plants, and oil platforms.

The company not only specialises in its already developed products, but is also able to develop tailored solutions for special applications.

At ILTA 2016 Protego will be showcasing a variety of products. One example is its DA-CG model, an in-line detonation flame arrester approved according to the American Standard 22 CFR part 154 and is accepted by the US Coast Guard. The device is symmetrical and offers bi-directional flame arresting for deflagrations, stable, and unstable detonations. The speed of incoming

Protego will be showcasing its DA-CG flame arrester

detonations is reduced by the effective shock absorber, which improves the flame quenching in the narrow gaps of the Flamefilter. The DA-CG arresters are available for NEC group D to C MESG≥0.65mm. The design has minimum pressure loss, low operating costs and lifecycle costs. The Flamefilter set is comprised of individual discs that are removeable to allow for thorough cleaning.

Visit Protego at booth 226 z

OPW Engineered Systems will present its wide product range at ILTA

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016

39

Keep it in the tank

LEAK DETECTION

Appropriate leak protection in chemical applications is essential for preventing catastrophic spills

Tanks and drums containing hazardous and flammable liquids require secondary and tertiary protection to prevent potential accidents, such as the Buncefield fire in Hertfordshire, England, in 2006, which left 45 people injured.

Lessons learned from that accident were translated into effective and practical guidance that industry would implement as rapidly as possible. This guidance, titled “Safety and environmental standards for fuel storage sites” (Part 42, p16), suggests that insufficient secondary containment contributed to the accident progression and states: “Bund wall and floor construction and penetration joints should be leak-tight. Surfaces should be free from any cracks, discontinuities, and joint failures that may allow relatively unhindered liquid trans-boundary migration. As a priority, existing bunds should be checked and any damage or disrepair, which may render the structure less than leak-tight, should be remedied.”

The EU Seveso II Directive holds a database of reported chemical related accidents and near misses of its member organisations. In July 1999, 16,561 tonnes of 30% solution of sodium cyanide at a top-tier COMAH

Buncefield fire

40

site was released through a leak in the tank to its bund. Of that quantity, only 4.260 tonnes were recovered with the remaining material lost to the ground and water. Recommendation again called for improvements to the secondary containment area. The entry does not state what level of protection this bund had, if any, but it can be assumed that since three quarters of the leaked material escaped the bund, the protection was either not there, its chemical resistance was insufficient, or this protection developed cracks allowing for the chemicals to seep through the bund.

National codes of practice Following dangerous occurrences varying in scale from minor near misses to those with catastrophic consequences, many countries have adopted codes of practice directed at installing and maintaining suitable secondary containment. US Environmental Protection Agency (EPA), for instance, refers to stationary tank bunds in the Resource Conservation and Recovery Act (RCRA) Subpart J, Tank Systems (40 CFR 264.

193). “Secondary containment systems must be: (b, 1) Designed, installed, and operated to prevent any migration of wastes or accumulated liquid out of the system to the soil, ground water, or surface water at any time during the use of the tank system; and (b, 2) Capable of detecting and collecting releases and accumulated liquids until the collected material is removed.”

To meet these requirements, the secondary containment area must be: (C, 1) “Constructed of or lined with materials that are compatible with the waste(s) to be placed in the tank system[…]” and (e, 1, iii) “free of cracks or gaps”. In the UK, Control of Pollutions Regulations 2001 also states that “the container must be situated within a secondary containment system which satisfies the following requirements[…] (c) its base and walls must be impermeable[…]”.

Secondary containment areas are typically constructed using concrete, because it is cost-effective and provides good structural strength. However, due

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016

LEAK DETECTION to its porosity, concrete can be easily permeated and has poor chemical resistance, making it susceptible to deterioration through chemical attack. In addition, concrete is highly prone to cracking due to substrate movement and freeze-thaw cycles.

Barrier coatings for secondary containment areas As concrete does not address the requirement for chemical resistance, an additional barrier atop is needed to prevent potential spillages from permeating the secondary containment area. Over the years, a variety of solutions have been trialled, from bitumen-based paints to epoxy resin-based systems. The right solution would depend on the type of media stored within the tank, size of the containment area, expected traffic, and weather conditions, among others.

Crack in concrete

Where the highest chemical resistance is required in case of extremely aggressive chemicals – such as concentrated mineral acids, alkali, amines, and alcohols – solvent-free epoxy novolac resinbased coatings are typically specified.

The drawback of these coatings, however, has long been associated with the very feature that made them chemically resistant – their rigidity.

The chemical reaction between the base and solidifier creates an almost impenetrable “physical barrier”.

Subsequently, once hardened and cured, these epoxy systems become completely liquid-impermeable and will have excellent resistance to immersion and exposure to a wide range of oil and chemical spillages. Rigidity of these coatings, however, also makes them inflexible and not best suited for heavy

trafficked areas or in cases where the underlying concrete develops cracks.

Concrete can develop cracks for many reasons, from excessive loading to thermal expansion/ contraction or during freeze/thaw cycles, which lead to the concrete’s movement and settlement.

A rigid coating would crack with the concrete, thus terminating chemical ASTM D412 testing protection in case of a spill. Recent advancements in polymer technology have resulted in order to protect ground water in the development of a hybrid epoxy against chemical pollutants. coating, which combines high crossThe testing takes two years to complete linking with rubbery domains in the and consists of a combination of crackpolymer chain, giving the coating bridging, chemical resistance, and a desired degree of flexibility. aging tests. Crack-bridging tests are first performed by creating a crack New material development within the concrete and ensuring the coating remains intact. This is followed One of the recently introduced coatings by chemical resistance testing, where to successfully incorporate these features the chemical is positioned onto the test comes from Belzona Polymerics and is coating so that the crack in the concrete known as Belzona 4361. To determine the is directly underneath. Signs of chemical coating’s crack-bridging abilities, Belzona attack are visually observed, in particular 4361 was first tested for elongation, to see if the chemical reagent attacks measured in accordance with ASTM the test coating severely enough to D412. When cured at 20°C, Belzona 4361’s penetrate through the crack due to the residual elongation was recorded at reduction in film thickness over the crack.

20%, which would be sufficient to bridge To replicate real life exposure or aging, a typical crack. To ensure the coating the coated test blocks are stored in maintains its flexibility at low temperatures, damp sand and placed outdoors. After a mandrel bend test in accordance with six months and two years respectively ASTM D552 was also performed, resulting of aging exposure, crack-bridging and in a pass at temperatures down to 0°C. chemical resistance tests are repeated.

To further test the coating’s crackBelzona 4361 passed the crack-bridging bridging abilities, Belzona 4361 was and chemical resistance tests after six submitted for a long-term testing at the months of aging exposure, which will be University of Stuttgart, Germany. The repeated again to complete the two university carries out testing to Chemical Belzona 4361 length of resistance award a German 93% Sulphuric Acid 52 weeks and beyond Federal Water Act (WHG) Approval, 37% Hydrochloric Acid 52 weeks and beyond which is part of 43% Phosphoric Acid 4 weeks a German water 25% Phosphoric Acid 39 weeks law for protecting 10% Acetic Acid 1 week surface water 2% Acetic Acid 52 weeks and beyond and groundwater.

25% Ammonia 4 weeks Only chemical containment Ethyl Acetate 52 weeks and beyond coatings with Ethanolamine 1 week WHG Approval Oil, Petrol and Diesel 52 weeks and beyond can be used Ethanol 52 weeks and beyond in areas where Methanol 17 weeks strict regulations Chemical resistance of Belzona 4361 are in place,

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016 41

LEAK DETECTION

Containment area

year’s testing. WHG presents rigorous independent testing and the results will be equally relevant in Europe and globally.

Chemical resistance was tested by coating rods and immersing them in specified chemicals for a period of up to 12 months. The accompanying table illustrates obtained results for some of the tested chemicals.

The coating is perfectly suitable to resist aggressive chemicals, as protection is only required to last until the leaked chemical can be recovered from the bund. Best practice reports in some countries do not specify a universal length of time the coating needs to resist the spilled chemical and some documents state 72 hours as an acceptable length of protection, such as the US EPA proposal 40 CFR 112.7(c).

Chemical protection in action Following its introduction in 2015, Belzona 4361 has been applied to protect the most critical assets. A secondary containment area in a Missouri, US, power plant was coated with Belzona 4361 after the existing chemical protection had failed. The bund in place to contain spillages from a 93% sulphuric acid tank experienced splashes, spills, and poor clean-up procedures, in addition to movement, which resulted in small gaps forming between the floor and bottom of the wall inside the containment area.

The power station has already been using a variety of Belzona materials ever since six years ago Belzona Gateway, the local distributor, solved a major leak problem, bringing its water treatment plant back in service. The station then turned again to its local Belzona 42

Bund protected with Belzona 4361

representative for a solution. After assessing the problem, Belzona Gateway proposed to use Belzona 4361 due to its high chemical resistance, flexibility, and good adhesion facilitating long-term sealing between the bund’s wall and floor.

The application was carried out in March 2015 and inspected recently, revealing that the protection was fully intact.

100% solids epoxy materials adhere well not only to concrete, but can be successfully used to protect a metal substrate from the chemicals. Added flexibility of the coating expands and contracts in sympathy with the underlying metal substrate. This second case study comes from China, where Belzona 4361’s chemical resistance and flexibility were put to the test when it was used to line two acid tanks at an oil field’s power plant.

The acid tanks contain 37% hydrochloric acid and were previously protected with an elastomer lining. In winter, when the plant transferred the hydrochloric acid from cold environment (<0°C) to room temperature (>20°C), the dramatic temperature change caused the existing elastomer lining to crack and, as a result, the tanks started leaking. Belzona 4361 was used to line two tanks in October 2015 and the client requested another two tanks to be coated in 2016.

Utilising coatings which provide chemical resistance as well as crackbridging ability is crucial to both comply with relevant standards and to guarantee lasting protection from spills. As the industry keeps improving the safety of its operations, material manufacturers need to keep up and continue to innovate by utilising novel raw materials. Of course, provision of an adequate secondary containment area is only one of the

many improvements that can be done to manage hazards and minimise risks.

Some of the other areas to consider include system automation and software, with leak detection technologies and alarm sounding. Such systems can dramatically reduce human error, which was found to be a major contributing factor in the progression of several accidents described in the Seveso Directive. Enhancing safety protocols will ultimately ensure that accidents such as Buncefield do not happen again. z

For more information:

This article was written by Marina Silva, marketing supervisor at Belzona Polymerics. Visit: www.belzona.com

References: 1. Broder, M.F., Technical Report: Building a Secondary Containment System, United States, Tennessee Valley Autority, 1994 2. Rivers, K., Buncefield Standards Task Group Final Report: Safety and Environmental Standards for Fuel Storage Sites, http://www. hse.gov.uk/comah/buncefield/bstgfinalreport. pdf, 2007 (Accessed on 1 January 2016) 3. European Commission, The Seveso Directive, http://ec.europa.eu/environment/seveso/, 2015 (Accessed on 10 December 2016) 4. 40 CFR 264.193 – Containment and Detection of Releases, https://www.law. cornell.edu/cfr/text/40/264.193, 2015 (Accessed on 20 December 2016) 5. Grainger, W. W., Secondary Containment Requirements: Quick Tips, https:// www.grainger.com/content/qtsecondarycontainment-requirements-182, 2015, (Accessed on 20 December 2016) 6. Water Resources, England, The Control of Pollution (Oil Storage) (England) Regulations 2001, http://www.legislation.gov.uk/ uksi/2001/2954/pdfs/uksi_20012954_en.pdf, 2001, (Accessed on 20 December 2016) 7. NCC Bund Lining, Bund Lining Materials, http:// www.bundlining.co.uk/BundLiningMaterials. html, 2014 (Accessed on 10 January 2016)

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LEAK DETECTION

The high-pitched snitch Using helium mass spectrometer leak detection provides operators with easy and precise knowledge of exactly where their product lines might be dripping

It is axiomatic in many industrial, process, and scientific environments that “everything leaks”. What is critical is to know how much is the leak rate, and sometimes where the leaks are.

Manufacturers and process systems operators who are under great pressure to improve yields, extend maintenance cycles, meet regulatory requirements, reduce costs, and increase profits can often benefit from the application of helium mass spectrometer leak detection (HMSLD) to measure and maintain the required leak integrity or specification.

HMSLD entails the use of helium as a “tracer” gas, which is introduced to a component or system to be tested and then quantified as it returns to the leak detection instrument via any leak path(s).

The rate of flow of helium is readily and precisely measured in the instrument using mass spectrometry principles, which allows accurate calculation of the actual leak rate. Using certain techniques, it is quite easy to determine the total leak rate of a component or system in order to compare to a standard, or to project the useful life of the item. It is also possible, using other techniques, to locate specific leaks in order to repair them. Both goals are easily accomplished with HMSLD. Why helium?

Using helium as the tracer gas has several well-documented benefits. Helium is an inert, nontoxic gas that is intrinsically safe.

The small helium molecule penetrates rapidly through extremely small channels.

The concentration of helium in air is only five parts per million, allowing for the smallest leaks to be detected without background interference. Helium leak detection makes it possible not only

Figure 1: Leak detection ranges using various technologies

to identify a leak, but to pinpoint leak location(s). This can help eliminate subjective interpretation encountered using other leak test methods.

Figure 1 indicates the range of leak rates which can reasonably be measured by various technologies. Mass spectrometerbased leak detection instruments can readily identify leaks as small as 1 x 10-11 atmospheric∙cc/second, and even smaller under controlled conditions. Testing with tracer gas eliminates the influence of temperature, as this limits the use of pressure decay technology. For example, it is quite important to realise that a minimal temperature increase of 0.05°C in a part pressurised with 2 bar (abs) and having an initial temperature of 21°C results in a pressure change of 0.34 mbar or 34 Pascal!

Additionally, pressure or vacuum decay indicates only that the part is leaking, while the use of tracer gas technology makes it possible to also pinpoint the exact location of any possible leak(s) by using sniffing technology. Tracer gas testing also eliminates the need for a drying cycle, as might be required after a “bubble test”, where the tested component is wetted.

In general, the advantages for the use of helium as a tracer gas can be defined as follows: • High sensitivity, several orders of magnitude greater than pressure decay or acoustic methods • Quantitative measurements • Non-destructive • Dynamic testing

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016

• Wide range of applications • Reliable Elements of an HMSLD instrument A mass spectrometer leak detector (MSLD) is a complete system for locating and/ or measuring the size of leaks in or out of a device or a container. This method of leak detection is initiated when a tracer gas, helium, is introduced to a test part that is connected to the MSLD system. The helium leaking from the test part diffuses through the system, its partial pressure is measured, and results are displayed.

The MSLD operating principle consists of ionisation of the gases in a vacuum and then accelerating the gas molecules across a drop in voltage and a magnetic field (figure 2). Within the spectrometer, which is “tuned” geometrically for the mass of helium, the helium ions are separated and collected, and the resulting ion current is amplified and indicated on the display.

A mass spectrometer leak detector consists of the following components: • A spectrometer tuned to detect helium • A vacuum system to maintain adequately low pressure in the spectrometer • Primary vacuum pumps to evacuate the part to be tested • Valves that enable the various stages of the leak detection cycle, from evacuation, to test, to venting • Amplifier and readout instrumentation that monitors spectrometer output signal 43

LEAK DETECTION

Figure 2: The operating principle of a mass spectrometer leak detector

• Electrical power supplies and controls that sequence valve operation, protective circuits, etc.

• Fixtures that attach the part to be leaktested to the leak testing equipment Applications for HMSLD in fluid handling include: • Hydraulics • Fuel and brake systems and components • Power steering • Transmissions and components • Pharmaceutical production systems • Refrigeration systems • Tanks and transport vessels A large number of automotive components, from air bags to transmission lines to brake lines, are manufactured to a precise leak rate specification, in order to guarantee their effective operation and minimum life. In process systems, maintaining leak integrity can greatly improve profitability by assuring efficiency of the process. Loss of pressure or vacuum, or leakage in or out of process gases or liquids can be readily found, predicted, and/or limited. In addition, it is easily possible to lengthen the planned maintenance interval.

There are also two general concerns when leak testing. One is the location of leaks and the other is the measurement of the total leakage rate of the part, as some leakage may be acceptable. In many cases, parts may be first tested to determine if they pass an acceptable level, and if not, the part may be taken offline and subjected to a second test with the intent of locating the leak.

Additionally, many parts may be tested in batches. If a batch fails, the individual parts in that batch may then be tested separately to identify the leaking part(s).

Remote control As many fluid handling systems are quite large, test operators may be spraying helium a considerable distance from the leak detector and are therefore unable to see or hear the instrument respond to helium. Wired remote controls

are limited by cable length. A wireless hand-held remote allows leak testing up to 100m from the base unit. All the major functions of the leak detector are available, the display has a bar graph of the leak rate, and a speaker provides a variable tone indicating the trend and relative size of the leak. Large systems, for which two test technicians were previously required, can now be tested by one technician, resulting in a faster, more reliable leak checking process and more efficient application of labour.

PC-based data management software can make the jobs of data collection, reporting, and documentation easier. Such programs give the user the ability to set up test parameters and collect data such as: • Pump-down profiles • Rate of rise plots • Archive test results and maintain product traceability • Perform statistical analysis • Export data to Excel for further analysis Summary Mass spectrometer leak detection using helium as a tracer gas is very precise, accurate, and easy to use. With a small amount of set-up and use of the correct test techniques, it can be much faster and neater than alternative leak testing techniques while assuring more stringent and accurate standards of leak integrity. z

For more information:

This article was written by Joh McLaren, marketing manger – leak detection at Agilent Technologies. Visit: www.agilent.com

Testing methods There are many different ways to leak test parts using helium as a tracer gas.

In general, the leak detection method is selected based on the actual working conditions of the part being tested. It is recommended that during leak testing, the same pressure differential be maintained and in the same “direction” as exists during the actual use of the part. For example, a vacuum system is tested with a vacuum inside the chamber, while a compressed air cylinder should be tested with a high pressure inside the cylinder.

44

A hand-held remote control unit for MSLD

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016

HEAT TRANSFER Although thermal fluids do not require constant assessment, maintenance should be frequent and comprehensive

Thermal fluids are challenging good old steam’s supreme position in heat transfer applications

Steam vs thermal fluid Steam has been a valuable servant to the human race, from a means of powering engines to a method of cooking food.

However, there is one area where steam has been outdone in recent years – heat transfer using thermal fluid. Historically, if heat transfer was needed in a chemical process and heating via naked flame was not feasible, steam was the preferred method. This was mainly due to the ease of sourcing water, the minimal cost of the resource, and the perceived absence of environmental issues. However, using steam in a heat transfer system comes with numerous drawbacks.

Pressure Steam requires a high operating pressure to achieve temperatures necessary for operating heat transfer systems.

For example, to reach 300°C, steam would require a pressure of 85 bars.

This is roughly 14 times the pressure inside an average bottle of bubbly.

One can picture what happens to Champagne when pressure in the bottle builds up and is given a means of release through the weakest point – the cork. The same effect can happen in an industrial environment, only 14 times stronger. Needless to say, the presence of high pressure brings with it the potential for serious health and safety risks.

When steam reaches critical pressure and has no way of venting, the system can burst a pipe, seam, or valve. This can result in an explosion of extremely hot steam and shrapnel from pipes. In contrast, most thermal fluid systems are vented and operate at atmospheric pressure, which means the risk to life and infrastructure from pressure is minimal.

Efficiency

Steam heat transfer systems rely on the generation of steam to drive pressure and ultimately, temperature. Due to this dependence on a delicate pressure balance, accuracy is generally limited to swings of ±6°C. This value is likely to increase as the system ages and corrosion takes its toll. In addition, condensate removal in steam heat transfer systems also affects the uniformity of heating.

In comparison, thermal fluid systems can have an average temperature control of ±0.8°C. This is a whopping precision of 99.8% at a temperature of 550°C. This precision is accomplished by efficient metering and mixing of cooler return fluid with warmer fluid from the supply line.

Maintenance Steam heat transfer systems require constant maintenance. In fact, in some

countries – such as the US – it is a legal requirement that a qualified person must continuously monitor and maintain operations. This creates an additional maintenance and cost burden that is not present with thermal fluid systems.

Furthermore, steam system infrastructure is far more intricate compared to thermal fluid applications. Safety valves, condensate return pumps, expansion joints, blow downs, chemical additions, and drains all need to be correctly managed for the steam systems to run efficiently.

Thermal fluid systems, on the other hand, only require a pump, an expansion and storage tank, and heat exchangers.

The maintenance problems do not stop there. Common issues with water and steam systems include corrosion and freezing. Despite steam systems depending on the use of demineralised water, the combination of water vapour and hot air alone is enough for corrosion and scaling to take place inside the pipes.

To combat this, stainless steel piping can be used, but this brings with it an added cost. Water in steam heat transfer systems is also prone to freezing if left unused in cold conditions – for example, if a facility closes for winter or the Christmas period.

If the water in the system freezes, there is a significant potential for pipes to burst, causing harm to the system and water damage to surrounding infrastructure.

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016 45

HEAT TRANSFER In comparison, thermal fluids are extensively used in systems designed to work at low temperatures. Specific types of fluid such as Globaltherm EDT or Globaltherm ECO containing antifreeze are specially formulated to pump at sub-zero temperatures and must be used in these cases. Although thermal fluids do not require constant assessment, maintenance should be frequent and comprehensive. Annual sampling of heat transfer fluids is a minimal requirement to demonstrate compliance with the Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR).

However, quarterly sampling is necessary to detect any short-term changes in the status of the fluid. This acts as a means of predicting future degradation and allows companies time to take appropriate action to avoid unnecessary downtime and high costs. A strategic maintenance plan is imperative for healthy and efficient heat transfer systems.

Increased safety and flexibility, combined with better efficiency and more

Steam requires a high operating pressure to achieve temperatures necessary for operating heat transfer systems

manageable maintenance, has meant thermal fluid systems have definitely come out on top in recent years. Steam may have once reigned supreme in heat transfer, but thanks to increasingly sophisticated products and maintenance practices, thermal fluids now dominate

industries from pharmaceutical to food and beverage manufacturing. z

For more information:

This article was written by Clive Jones, CEO of Global Heat Transfer. Visit: www.globalheattransfer.com

Donâ&#x20AC;&#x2122;t miss your chance to appear in the July/ August 2016 issue of Fluid Handling International For editorial suggestions contact: Ilari Kauppila, ilari@woodcotemedia.com, +44 (0) 208 687 4146 For advertising information and prices contact: Georgina Barry, georgina@fluidhandlingmag.com, +44 (0) 208 648 7092 Next issue features include: Industry spotlight: Oil Fluid focus: Mixers, maintenance solutions Regular features: Pumps, valves, meters

Advertising deadline: 1 July 2016 46

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016

From the vacuum they came

VALVE MANUFACTURE

An overview of vacuum-treated valves and their significance Manufacture of valve castings is a methodical process, which starts from making wooden patterns, proper methoding (creating a plan for a mould), making the mould, adding the steel scrap metal into the furnace, and pouring the molten liquid into the pits, which gives the valve the shape that is required. Selection of proper methoding is crucial for the durability of valve castings manufactured in a foundry. Methoding requires the hand of a skilled person, who studies the casting and manufacturing processes in detail and has an idea about where the runners and raisers are to be placed and the point of pouring the liquid metal into the moulding pits in order for the end product meets the full requirements of the user. The finished casting should be free of pores with minimum or no repairs, such as weld repairs. However, one may find porosity in the valve castings to be where a sand moulding process is needed. Sand moulding is very common across the industry.

In the light of these issues which may result in porosity in valve castings, foundries have taken to making investment castings. Here the finish of the casting is very smooth and does not

S. Sekar, valve specialist

require any further sanding or machining process. This process involves using wax moulds. After moulding, the wax becomes waste and has to be discarded. This is also known as the lost wax process. However, here too there are shortcomings. Valves produced by this method become expensive beyond 3” size and are mostly good for when valves are produced in large volumes. There are still other foundries that follow the shell-moulding process.

Introduction to VOAD There are many technologies used by different foundries towards fulfilling the needs of demanding customers. One such advancement in the field of valve castings is called vacuum technology, which uses the state-of-the-art Vacuum Oxygen Argon Decarburisation (VOAD) furnace. The benefits of using VOAD technology in relation to the conventional castings has recently been understood by operators and the demand for castings made by vacuum technology has increased amongst discerning customers.This cutting-edge technology is preferred over others for the manufacture of Duplex, Super Duplex, Speciality Alloys, Monel and Inconel valves.

In order to meet stringent project deadlines, valve manufacturers use a fully integrated enterprise resource planning (ERP) system to ensure that all the facilities and resources that are required for producing valve castings are available in the plant. This includes cobalt and iridium as radiography sources, as well as ultrasonic, diepenetrant, and magnetic particle testing.

Reaching out to customers and educating them is important work, which follows any developmental activity. It is the customer who decides whether to go for a particular product based on product quality, the unique characteristics that the product possesses, and the awareness

created by the manufacturer by instilling in the customer’s mind the features of the product. In management and marketing terms, this would be called branding and it has its value. In India, companies like Emerson Process Management’s Fisher Controls India Chennai is using castings made using the VOAD process at the HPCL – Mittal Energy expansion project at the energy producer’s Gurugobind Singh refinery in the Bhatinda district of Punjab. Emerson Process Management Fisher Controls India is the manufacturer of Fisher control valves in India.

Benefits of vacuum treatment In the past few years, foundries have deployed the following high technology options: • Automated mould lines installed

by IMF (Italy), based on continuous flow manufacturing concepts.

Mould setting, closing, and core setting is performed automatically to the farthest extent feasible.

• VOAD furnace to produce high quality castings, thus enabling decarburising, desulphurisation, argon purging, and degassing hydrogen, nitrogen, and oxygen from the metal. The result is a casting that is by far the best the industry can receive. Thanks to vacuum technology, foundries with such facilities are able to supply their customers with materials like Duplex, Super Duplex, Inconel, Monel, and Haste alloy, which are mainly used in the oil and gas sector and C12A used in the power industry.

• Foundries use Magma software for methoding development. The engineering department uses 3D solid modelling for method design and 3D solidification simulation programs to ensure high design quality.

Patterns are also manufactured using CNC machines and CAD/CAM technology within the premises.

FLUID HANDLING INTERNATIONAL l MAY/JUNE 2016 47

VALVE MANUFACTURE • Foundries have bunkers for nondestructive examination of cast metal, including using cobalt 60, 100 curies, and iridium sources as well.

Foundries with VOAD furnaces can manufacture about 50,000 tonnes of valve castings per annum. VOAD is used as a secondary treatment system to produce exotic alloys, including the afore-mentioned Super Duplex, Monel, Inconel, and other high nickel alloys that are used in critical application valves.

Chromium has a high affinity for carbon, so preferential oxidation of carbon is achieved in case of very low carbon steels by raising the reaction temperatures and reducing the partial pressure of carbon monoxide by vacuum, supported by vigorous argon purging. Lower partial pressure in the vacuum chamber removes both hydrogen and nitrogen gases.

Better control of steel cleanliness is also a prime benefit of VOAD process. The presence of alumina in all steel-making processes is a major contributor to poor steel cleanliness. The VOAD process enables manufacturers to create slags, which have a high affinity for alumina.

In addition, the dynamic mixing of

molten steels with argon during the degassing cycle enables the production of very clean steel products to meet the various customer requirements and also customised specification, which exceeds given standards.

Thus, the benefits of the VOAD process are becoming clear: • Considerably lower material costs due to the ability to use less expensive high-carbon ferro-alloys, sulfur-bearing scrap and alloys, low-quality scrap, and returns as raw materials.

• Pinpoint process control accuracy in achieving the desired chemistries, with precise control of carbon to 0.01% and lower.

• Rapid de-sulfurisation to less than 0.001%.

• The ability to obtain cleaner metal, with residual oxygen, nitrogen, and hydrogen comparable to those achieved in vacuum degassing.

The process AOD is part of a duplex process in which scrap or virgin raw materials are melted in an electric arc furnace or induction furnace and subsequently decarburised

and refined in aspecial AOD vessel.

Controlled injection of oxygen mixed with argon or nitrogen decarburises the molten metal with a minimum of unwanted metallic oxidation.

Deoxidation, desulphurization (and in the case of low-alloy steels, dephosphorisation) and recovery of desirable metals from the slag are carried out in the AOD vessel.

Degassing, homogenisation, and inclusion flotation proceed during various stages of the process to produce a clear and uniform product. Awareness of VOAD processes in the manufacture of valve castings has made discerning customers, like HPCL – Mittal Energy for its Gurugobind Singh refinery project in Batinda, India to specifically request for valve castings made using the VOAD method. z

For more information:

This article was written by S. Sekar, a B.Tech in Chemical Engineering, and valve specialist in oil and gas, refinery, and Chemical Process industries. He is the organising secretary of CHEMCON 2016 (Chemical Engineering Congress), which is the 69th Annual Event of the Indian Institute of Chemical Engineers to be held at A.C.College of Technology, Anna University from 27th Dec to 30th Dec 2016. Email: sekrajc@yahoo.com and mobile: +919566024721

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Sealing, Connecting and Protecting the World’s Pipelines

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