CVX-P Valve Instruction Manual

Instruction Manual Form 5472 January 1999

Design CVX-P Pressure Reducing Valve

Design CVX-P Pressure Reducing Valve Contents Introduction

.............................. 1 Scope of Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Principle of Operation

................... 2

Valve and Instrument Installation

...... 2 Piping Considerations . . . . . . . . . . . . . . . . . . . . . . . . 3 Location of Pressure Tap . . . . . . . . . . . . . . . . . . . . . . 3 Control Strategies . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Installation

................................ 3

Maintenance

.............................. 4 Servicing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Removal of Valve Bonnet and Trim . . . . . . . . . . . . . 5 Valve Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Parts Ordering . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8

Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9

Introduction W7354/IL

Scope of Manual

Only personnel qualified through training or experience should install, operate, and maintain a Design CVX-P valve. If you have any questions about these instructions, contact your Fisher Controls sales office or sales representative before proceeding.

Figure 1. Design CVX-PA Pressure Reducing Valve

Description The Design CVX-P pressure reducing valve (see figure 1) provides an efficient, and yet rugged, way to reduce steam pressure. Typical installations include utilities and process steam applications where pressure and temperature reductions need to be separated into separate stages, and, yet, where dependable and accurate control is required.

D102621X012

This instruction manual includes installation, maintenance, and operation information for the CON-TEKR Design CVX-P control valve. Refer to separate instruction manuals for instructions covering the actuator and accessories.

Design CVX-P Pressure Reducing Valve Table 1. Specifications (for Standard Designs)

End Connection Sizes Design CVX-P: R 1 through 20-inch steam inlet and R 2 through 42-inch steam outlet End Connection Types R ANSI Buttweld (all sizes) R ANSI Raised Faced Flanges (all sizes) R ANSI Socket Weld (1 through 3-inch)

Configurations R Angle Pattern (Standard) R ”Y” Pattern (Optional) R ”Z” Pattern (Optional)

ANSI Ratings R Class 150 through 4500

Bonnet Types Bolted: Class 150 through 4500 Shutoff Classifications per ANSI/FCI 70-2 R Class IV (standard) R Class V (optional)

Special materials such as F91 or stainless steel possible upon request Control Plug Sizes 36 through 350: 410 SS with Alloy 6 Guiding and Seating Surfaces Sizes 385 through 510: SA182 GR F22 with Alloy 6 Guiding and Seating Surfaces Stem Stem Sizes 1/2 through 1-1/4 Inch Diameter: SA 479 Type XM-I9 Stem Sizes 2 Inch Diameter and Larger: SA638 Grade 660 Cl A Control Sleeve Sizes 36 through 68: SA182 Grade F22 Ion Nitrided Sizes 82 through 510: SA217 Grade WC9 Ion Nitrided Seat Sizes 36 through 68: SA479 Type 410 with Alloy 6 Seating Surface Sizes 82 through 510: A743 Grade CA15 with Alloy 6 Seating Surface

Trim Characteristics R Linear (standard) R Equal Percentage R Special

Body/Bonnet R SA105 Carbon Steel R SA182 GR Fl l (1-1/4 CR- 1/2 MO) R SA182 GR F22 (2-1/4 CR- 1 MO)

Piston Rings Alloy 25 or Alloy 6 Gaskets Inconel/Graphite Packing Graphite/Grafoil

Principle of Operation

through the multiple orifice diffuser(s) to the outlet pipe.

The positioning of the valve plug within the control sleeve controls the steam flow (see figure 2). The control sleeve has an array of orifices to provide the control characteristic specified. As the plug is lifted from the seat, steam is permitted to pass into the center of the control sleeve, and out through the seat orifice. A signal from the pressure control loop to the valve actuator moves the valve plug within the control sleeve which increases or decreases the amount of free flow area. Retracting the plug increases steam flow.

Valve and Instrumentation Installation

The outlet section of the valve is usually comprised of one to three silencing diffuser sections. As the steam exits the seat orifice, it enters one or more concentric diffuser sections designed to further decrease steam pressure in stages. Flow is directed radially and axially

2

The Design CVX-P valve should be located in an easily accessible location with sufficient clearance for maintenance. Suggested minimum clearance for removal of the actuator and plug is shown on the dimensional drawings that are created specifically for each valve. Although the preferred position for easy maintenance is vertical, the Design CVX-P valve can be mounted in any position except with the stem pointing down. For additional information regarding installa-

Design CVX-P Pressure Reducing Valve tions, such as drains, please refer to bulletin 85.1:015 CON-TEKR Steam Conditioning Valves Installation Guidelines.

Piping Considerations Indiscriminate use of pipe reducers or expanders to match the valve outlet to field piping is not recommended. Mismatched valve outlet piping can result in increased system noise and vibration levels. If field piping requires the use of these devices, reducers on the valve inlet should have a maximum angle of 30 degrees while outlet expanders should be limited to a maximum of 20 degrees. These recommendations are made to keep noise and vibration levels to acceptable limits.

Location of Pressure Tap It is important that the pressure tap be located at a distance of not less than ten (10) feet from the outlet of the valve. The pressure sensor and transmitter should be mounted in accordance with the manufacturer’s instructions.

Control Strategies Pressure control is normally a closed loop feedback system. The process variable can be either the upstream or downstream pressure, depending on the application. See figure 3 for a typical feedback control strategy.

Installation WARNING Personal injury or equipment damage caused by sudden release of pressure may result if the Design CVX-P valve is installed where service conditions could exceed the limits of the pressure class noted on the nameplate. To avoid such injury or damage, provide a relief valve for over pressure protection as required by government or accepted industry codes and good engineering practices.

1. Before installation, all piping upstream of the valve must be blown clean so that no particles, such as welding slag, dirt or other foreign matter, are left in the

pipe. Use care to keep foreign matter out of the line openings while preparing the valve installation.

2. Verify that the valve is clean inside. If possible, before fitting in the line, connect the actuator to a temporary air supply and operate to verify positioning. Disconnect the instrument lines (if applicable).

WARNING Do not lift the valve by its actuator yoke.

Personal injury or damage to equipment could occur if the valve is improperly lifted into place.

3. Arrange a lifting sling around the main valve body to safely lift the valve to the pipe opening.

WARNING Do not expose the valve to undue stresses by installing it in bent pipes or flanges. Personal injury and equipment damage could result from flange sealing failure due to improper installation.

4. Flanged Connections—Grease the flange connection bolts with a high temperature thread lubricant.

Install flange gaskets and connection bolts per accepted practices and tighten securely.

5. Welded Connections—Welding procedures should be in accordance with the applicable codes and the base materials. For preheat, welding electrodes, and postweld heat treatment, refer to the applicable codes and practices. Materials are specified on the customer specification sheet. If the valve inlet and outlet connections are to be welded with the valve assembled, the valve plug should be maintained off the valve seat during all associated operations. If the valve is to be welded by SMAW process, the valve should be disassembled for welding to ensure that any weld slag is removed from the valve.

6. A typical control loop is illustrated in figure 4. A pressure transmitter senses the pressure downstream (or upstream in backpressure control applications).

The pressure controller sends a signal to the actuator positioner opening or closing the Design CVX-P as required to maintain pressure. A rising stem opens the Design CVX-P to allow additional steam flow.

CAUTION Pneumatic lines (where applicable) should be thoroughly blown clean with dry air before connection. Check electronic lines for correct connection.

3

Design CVX-P Pressure Reducing Valve

W7015-1 / IL

Figure 2. Design CVX-P Cross Sectional View

7. If foreign debris has been introduced into the valve or upstream piping during installation, it must be removed prior to using the valve for the first time. A Blowout or Blow-through tool can be purchased to match the Design CVX-P and allow piping blowdown without removal of the valve from the line.

8. After cleanliness of the piping system has been assured, connect instrumentation and power supply to the Design CVX-P valve actuator and associated equipment.

9. Monitor the Design CVX-P valve as the system is brought on line. Some visible vapors may be seen as the lubricants are heated. If you see any steam leaks after startup, disassemble the valve and replace the gaskets. If the stuffing box leaks, tighten gland nuts (key 68). If leakage continues, replace the packing.

4

Maintenance Servicing Due to the care Fisher Controls takes in meeting all manufacturing requirements (heat-treating, dimensional tolerances, etc.), use only replacement parts manufactured or furnished by Fisher Controls.

WARNING Avoid personal injury or property damage from sudden release of process pressure or bursting of parts. Before performing any maintenance operations: R Disconnect any operating lines providing air pressure, electric power, or a

Design CVX-P Pressure Reducing Valve STEAM

PC

PT

B2646 / IL

Figure 3. Typical Feedback Control Strategy

control signal to the actuator. Be sure the actuator cannot suddenly open or close the valve.

R Use bypass valves or completely shut off the process to isolate the valve from process pressure. Relieve process pressure from both sides of the valve.

Drain the process media from both sides of the valve.

R Vent the power actuator loading pressure and relieve any actuator spring precompression.

R Use lock-out procedures to be sure that the above measures stay in effect while you work on the equipment.

WARNING Residual system pressure may be released during the following steps if the system was improperly isolated or vented. Use extreme care to prevent personal injury while loosening any fasteners in the pressure boundary.

Removal of Valve Bonnet and Trim 1. Disconnect all field connections to the positioner and actuator and remove the actuator from the valve.

Consult actuator manufacturer’s documentation for assistance on actuator removal.

2. Loosen the gland stud nuts (key 68) and remove along with the gland follower (key 65). If possible, remove packing rings (key 64) from the stuffing box.

3. Loosen bonnet bolts/nuts (key 55) using an even pattern to avoid uneven expansion of the gaskets. Remove the entire bonnet assembly, pulling evenly in line with the valve stem (key 23) centerline. Uneven bonnet removal can result in galling or bending of the valve stem. If difficulty is encountered removing the bonnet, check the bonnet for alignment and straighten the bonnet before making further attempts to remove it from the valve body.

Note The bonnet must be handled with care while removed from the body. Damage to the bonnet can result in gasket leakage while the valve is in service. Protect the bonnet by placing it on clean cloth or wood while the valve is disassembled.

4. Dislodge any remaining packing rings (key 64) from the stuffing box. Remove the gland ring (key 63) from the bottom of the stuffing box.

Inspect all parts; gland ring (key 63), gland follower (key 65), valve stem (key 23), and gland studs/nuts (key 68/69) for signs of wear. Replace all parts that are damaged or show excessive wear.

5. Inspect the bonnet guiding surfaces and gasket mating surfaces. Light damage on the guiding surface may be repaired with emery cloth or other suitable material. Damage to the gasket mating surface may require bonnet replacement to avoid leakage.

5

Design CVX-P Pressure Reducing Valve

FISHER CVX-PA-FSB

STEAM

STEAMFLOW

B2647 / IL

Figure 4. Typical Design CVX-PA Installation

6. Remove the seat (key 24), control sleeve (key 21), and plug assembly (key 22, 23, and 53) as a single unit by grasping the valve stem (key 23) and pulling the assembly from the body cavity.

7. Separate the control sleeve (key 21) from the seat (key 24) and remove the plug assembly (key 22, 23, and 53) from the control sleeve by pushing the plug assembly down through the lower end of the control sleeve. Reference figures 6 and 7 for guidance in performing this disassembly.

8. Inspect hardfaced guiding and seating surfaces of the plug assembly and seat, as well as (if applicable) the piston rings (key 45 and 46), for wear or damage and replace if necessary.

6

9. Polish the control sleeve guiding surface. If the guiding surface is damaged, replace the control sleeve.

10. Clean the valve seat. Light damage to the seating surface may be factory repaired by re-machining the 45 degree seating angle.

11. Remove all used gaskets and foreign matter from the interior of the valve and from the inlet and outlet openings. If the valve is equipped with one or more diffusers, remove any foreign matter that may be trapped in the diffusers or that may be plugging the radial ports. Inspect all valve body guiding and sealing surfaces for any signs of wear.

Design CVX-P Pressure Reducing Valve Valve Assembly

Table 2. Recommended Bonnet Bolt Torque RECOMMENDED BOLT TORQUE(1)

1. Cleaning—Make certain that all interior surfaces of the valve body and bonnet (including the stuffing box)

BOLT SIZE

are clean and free of dirt, including the inlet and outlet openings. All surfaces of the valve interior that receive mating parts should be given special attention when cleaning. All sliding, fit, and gasket sealing surfaces should be coated with Felpro C5A or other similar high temperature lubricant prior to reassembly. Refer to figure 5 for reference.

1/2

13

9/16

12

95

5/8

11

125

3/4

10

200

7/8

9

290

1

8

405

1-1/8

8

550

2. Install the spiral wound seat seal gasket (key 41). If valve is installed horizontally, the gasket can be held in place by sticking it to the valve body with a liberal coating of high temperature grease. Check to make sure cage is located below the minimum cage depth mark on the inside of the body, near the top of valve.

This will ensure that the gasket is properly seated.

1-1/4

8

730

1-3/8

8

980

1-1/2

8

1290

1-5/8

8

1650

1-3/4

8

2070

1-7/8

8

2560

2

8

3130

3. Before insertion of the plug assembly (key 22,23,53) with new piston rings (key 45, 46) in the control sleeve, all surfaces should be cleaned and generously lubricated with high temperature grease.

Insert the plug into the control sleeve (key 21), taking care not to misalign the two. The piston rings will need to be slightly compressed to pass into the sleeve. Any binding between the plug and sleeve must be thoroughly investigated and corrected prior to proceeding.

2-1/4

8

4490

2-1/2

8

6200

3

8

10800

4. Reattach the seat (key 24) to the control sleeve (key 21). Refer to figures 6 and 7 for guidance. Insert the control sleeve (key 21), plug assembly (key 22, 23, 53), and seat (key 24) as an assembly. The parts should slide easily into the valve body until the seat rests on the seat gasket (key 41). If resistance to insertion is felt, remove the seat and control sleeve and determine the cause of the problem before attempting reinstallation.

5. Lubricate bonnet studs and fully screw them into the valve body.

6. Install the sleeve gasket (key 43).

7. Attach the bonnet gasket (key 44) in the bonnet gasket retaining groove with high temperature grease.

8. Lubricate the bonnet locating surfaces and carefully install the bonnet (key 6). Use care to avoid bending the stem. There will be a separation of about 1/8-inch between the bonnet and the valve body after the bonnet is fully inserted. Inspect the bonnet gasket to ensure it is properly located.

Inch

THREADS PER INCH

LbfRft 71

1. Torques for lubricated studs with heavy hex nuts.

9. Install bonnet stud washers and nuts (key 52 and 55) and hand tighten.

10. Tighten the bonnet nuts (key 55) in a uniform, multistage cross pattern. Monitor the distance between the bonnet and body and keep it even to ensure that the bonnet is being torqued evenly. It is recommended that torquing be performed in a minimum of four torque levels until the final torque level is achieved. You may need to torque multiple times at each torque level to ensure that the bonnet is torqued evenly. Required torque levels can be found in table 2.

11. After the bonnet has been torqued to the required level, check the plug movement to ensure that the plug moves still moves freely.

12. Recheck the cleanliness of the stuffing box. Insert the gland ring (63) over the stem and into stuffing box.

Measure the depth of stuffing box before and after ring insertion to be certain that it has traveled to the bottom of the stuffing box. Insert packing rings (64), after lubricating with high temperature grease, into the stuffing box and staggering the gaps on adjacent rings.

The gland follower (key 65) can be used to ensure that each packing ring is pushed down before installing the next packing ring.

7

Design CVX-P Pressure Reducing Valve Table 3. Recommended Packing Nut Torque STEM DIAMETER

MAXIMUM TORQUE

MINIMUM TORQUE

LbfRft

LbfRft

150 300 600 900 1500 2500 150 300 600 900 1500 2500 300 600 900 1500 2500

6 7 10 13 16 18 12 15 22 30 37 45 27 37 46 57 67

4 5 7 9 11 13 8 10 15 20 25 30 18 25 31 38 45

1-1/4

300 600 900 1500 2500

36 49 61 75 90

24 33 41 50 60

2

300 600 900 1500 2500

48 67 88 108 125

43 61 80 98 115

ANSI PRESSURE CLASS

Inch

1/2

3/4

1

Table 4. Troubleshooting Guide Problem

Possible Solution

Stem packing is leaking

Tighten stem packing nuts

Stem packing is leaking after tightening stem packing nuts

Repack and replace worn parts as needed

Actuator cannot open valve

Check actuator calibration Check for overtightening of the packing nuts Check for alignment between actuator and valve

Actuator action is “sticky� sticky

Check positioner calibration Replace plug, cage, stem guide and/or packing follower

Water in steam line Noise and vibration seem high Bonnet gasket is leaking

13. After all packing rings are installed, thoroughly lubricate the gland studs (key 69) and insert the gland follower (key 65) and the gland flange (key 66). Tighten the gland stud nuts (key 68) tight enough to block leakage but not so tight that stem travel is hindered.

Consult table 3, for recommended torque levels. Evenly tighten the nuts to the maximum level, then loosen and retighten to the minimum torque level. After operating, further tightening may be required to prevent leakage.

14. Install the actuator on the valve in accordance with the manufacturers standard procedure. After calibration of the actuator, the valve should be ready to return to service.

8

Check that steam traps are functioning properly Review piping configuration and insulation Inspect valve diffuser Inspect body/bonnet mating surfaces, replace bonnet gasket. Ensure bonnet bolts are properly torqued

Troubleshooting Table 4 is intended as a basic first line troubleshooting guide. Contact your Fisher Controls sales office or sales representative for assistance if you are unable to resolve your field operation problem.

Parts Ordering Each Design CVX-P is assigned a serial number that can be found on the bonnet flange. Refer to the serial number when contacting your Fisher Controls representative for technical assistance. When ordering replacement parts, refer to the serial number and key numbers for each part required. The key numbers in figure 5 and the Parts List can be used to help in part identification.

Design CVX-P Pressure Reducing Valve 23 69

66

68

65

64

63 6

53

54

44

55

43

52 46 45 22 21 1 24 41

B2639 / IL

Figure 5. Design CVX-PA Assembly

Parts List

Key

Description

24* Key

Description

01

Body SA 105 SA 182 Grade F11 SA 182 Grade F22 Bonnet SA 105 SA 182 Grade F11 SA 182 Grade F22 Control Sleeve SA 182 Grade F22 Ion Nitrided (SOD Sizes 36-68) SA 217 Grade WC9 Ion Nitrided (SOD Sizes 82-510) Plug SA 479 Type 410/Alloy 6 (SOD Sizes 36-350) SA 182 GRF22/Alloy 6 (SOD Sizes 385-510) Stem SA 479 Type XM-19, less than 2” diameter SA 638 Grade 660 Cl A, 2” diameter and larger

06

21*

22*

23*

*Recommended spare parts

Seat SA 479 Type 410/Alloy 6 (SOD Sizes 36-68) A 743 Grade CA 15/Alloy 6 (SOD Sizes 82-510) 41* Seat Gasket, Inconel 600/Graphite 43* Sleeve Gasket, Inconel 600/Graphite 44* Bonnet Gasket, Inconel 600/Graphite 45/46* Piston Rings, Alloy 25 or Alloy 6 52 Bonnet Stud Washer, Plated Steel 53* Stem Pin, 316 SST 54 Bonnet Stud SA 193 Grade B7, SA105 Valves SA 193 Grade B16, SA182 GR F11 and F22 Valves 55 Bonnet Stud Nut SA 194 Grade 2H, SA105 Valves SA 194 Grade 7, SA182 GR F11 and F22 Valves 63* Gland Ring, SA 479 Type 316 64* Packing Set, Graphite/Grafoil 65* Gland Follower, SA 479 Type 316 66* Gland Flange, SA 479 Type 316 68* Gland Stud Nut, SA 194 Grade 2H 69* Gland Stud, SA 194 Grade B7

9

Design CVX-P Pressure Reducing Valve

INTERNAL THREADS

2

NOTES: 1. UNSCREW SEAT FROM CAGE. 2. REMOVE PLUG FROM LOWER END OF CAGE.

EXTERNAL THREADS

B2640 / IL

1

Figure 6. Design CVX-P Trim Assembly (Sizes 160 and Smaller)

INTEGRAL CAGE PIN (TWO, 180_ APART)

2

PIN SLOT (TWO, 180_ APART) NOTES: 1. ROTATE SEAT UNTIL CAGE PIN ALIGNS WITH SEAT SLOT. SEPARATE SEAT FROM CAGE. 2. REMOVE PLUG FROM LOWER END OF CAGE.

1

B2641 / IL

Figure 7. Design CVX-P Trim Assembly (Sizes 175 and Larger)

CON-TEK, Fisher, Fisher-Rosemount, and Managing The Process Better are marks owned by Fisher Controls International, Inc. or Fisher-Rosemount Systems, Inc. All other marks are the property of their respective owners.

EFisher Controls International, Inc. 1999; All Rights Reserved

For information, contact Fisher Controls: Marshalltown, Iowa 50158 USA Cernay 68700 France Sao Paulo 05424 Brazil Singapore 128461 10 Printed in U.S.A.