VALVTECHNOLOGIES, INC. INSTALLATION, OPERATIONS & MAINTENANCE MANUAL STEAM CHOKE VALVES

Transcription

1 VALVTECHNOLOGIES, INC. INSTALLATION, OPERATIONS & MAINTENANCE MANUAL STEAM CHOKE VALVES Page

2 STEAM CHOKE VALVES The Valvtechnologies steam choke is designed for the harsh conditions associated with steam injection. The rugged, maintenance-free steam choke features a self-adjusting, double liveloaded design. A The stem/fork packing is isolated from the bonnet seal arrangement and is live-loaded. Belleville springs on the packing glad bolts self-adjust to maintain constant packing load regardless of thermal cycling. This design reduces the potential for packing leaks. Valvtechnologies offers a 4-year zero emissions guarantee for steam chokes.* Belleville springs accommodate for thermal expansion of the choke s internal components. B During thermal cycling in startup or normal operation, the Belleville springs self-adjust to maintain an ideal contact load between the control discs. This self-adjustment eliminates the possibility of lock-up, regardless of process temperature or pressure (within the material limits). The internal springs also provide a constant load to prevent external leakage through the bonnet packing. C The control discs are designed to provide precise control so that production rates are controlled with a high degree of accuracy. The discs also provide long-term erosion resistance in high-velocity, saturated steam service. Various orfice shapes, sizes and configurations are available for a wide range of production rates and control requirements. The steam choke can easily be retrofitted with new discs if well conditions or production rates change over time. *Guarantee valid only if Valvtechnologies installation and operations manual procedures are followed. A A B C Page 2

3 BILL OF MATERIAL Pressure Rating to ANSI 1500 Max. Cold Working Pressure is 3,650 psi Max. Operating Temperature 800 F ITEM DESCRIPTION MATERIAL 1 2 CHOKE BODY SW WCB 2 DISC 2-1/ H1150/ QPQ 17-4 H DOWEL PIN.188 X 5 ALLOY STEEL 4 FORK 28 F/T 28, Y PH/QPQ CB7 Cu 5 BOTTOM BEARING 410 S.S. 6 TOP BEARING 316 S.S / # BELL- VILLE SPRING INC. 718/HT 8 BONNET 28F/T28, Y S.S. 9 GLAND 1-1/2 2500# 316S.S./QPQ 316 S.S 10 ADAPTER 4130 H.T. 11 STUD, BONNET B8M 12 NUT, BONNET GR8M 13 LOCKWASHER, BONNET CS 14 STUD, GLAND B8M 15 SPRING, GLAND 302 S.S. 16 NUT, GLAND GR8M # MOUTING BRACKET WCB 18 SOCKET HEAD CAP- SCREW, MOUNTING GRAFOIL 19 LCOKWASHER, MOUNTING CS 20 RETAIN RING, INTERNAL 302 S.S. 21 BOTTOM SEAL GRAFOIL 22 GASKET, BODY GRAFOIL/ INCONEL 23 PACKING, BONNET INCONEL/ GRAFOIL 24 PACKING GLAND INCONEL/ GRAFOIL 25 SETSCREW A574 Page 3

4 This manual describes the procedures to be followed to ensure safe and successful installation, operation and maintenance of the Valvtechnologies Steam Choke Valve, assuring a trouble free service life. Failure to follow the guidance contained within this manual will void the Valvtechnologies warranty.. Difficulties encountered in the operation or maintenance of Valvtechnologies Steam Choke Valve should be directed to a Valvtechnologies, Inc. authorized repair center or to the Valvtechnologies, Inc. Houston manufacturing headquarters. INSTALLATION RECEIVING AND PREPARATION PROCEDURE 1) Remove shipping protection. 2) Inspect Steam Choke valve for transportation damage. 3) Inspect Steam Choke valve bore and remove any debris. 4) Cycle the Steam Choke valve inspecting the disc for damage. WARNING! STEAM CHOKE VALVES SHOULD NEVER BE USED AS A STRUCTURAL MEMBER. IMPORTANT! Steam choke valves mounted with electric actuators should be cycled to the mid-stroke position before cycling under power. Actuators are not to be mounted, removed, adjusted or re-installed to or from Valvtechnologies steam choke valves except by trained Valvtechnologies personnel. ORIENTATION Steam choke valves must be installed with the FLOW ARROW pointing from high to low pressure with the valve in the closed isolating position. Alternatively the high-pressure end will be labeled. The high-pressure end is defined as the end with the highest pressure, with the steam choke valve in the closed isolating position. Page 4

5 WELDING, STRESS RELIEVING AND INSULATION The use of radiation shields is advised if heat damage to the actuator is a concern. Care is to be taken to minimize weld slag and splatter within the steam choke valve. Do not strike arcs on the steam choke valve. Valve must be OPEN during welding. Excessive temperature and incorrect insulating or stress relieving technique may damage the steam choke valve and void the warranty. IMPORTANT! Localized Stress Relief is acceptable, do not furnace stress relieve without consulting Valvtechnologies Engineering. Steam Choke Valve insulation is prohibited during stress relieving. DO NOT STRESS RELIEVE 800ºF 1100ºF MAX. No insulation is to be applied to the Steam Choke Valve POST WELDING AND STRESS RELIEVING PROCEDURES Piping system shall be cleaned and flushed. Limit switch and position indicator operation should be observed as the steam choke valve is cycled several times. Steam choke valves and valve assemblies should never be used as load bearing members or be used as part of a load bearing structure. Page 5

6 ASSEMBLY Only approved Valvtechnologies components should be used in the assembled valve. STEP 1 Check parts against the bill of material to ensure all parts are on hand. STEP 2 When installing bottom dowel pins the measure over pin (MOP) should not exceed STEP 3 Place the bottom seal (Grafoil) into the body. STEP 4 Install bottom disc The bottom seal should be pressed over the dowel pins. Damage will occur if the gasket is not carefully installed. Surface of disc should be free of dirt and debris. Needle nose pliers should have rubber tips (or coated with plastic) to protect disc from chipping. Page 6

7 ASSEMBLY (CONTINUED) Cut two 6 Grafiol/Inconel Ropes. The cut should be at a forty-five degree angle STEP 6 Install Gasket Surface of disc should be free of dirt and debris. STEP 7 Install the fork dowel pins with a MOP of maximum and place the top disc on the bottom of the fork. STEP 8 Place the fork into the choke body with the scribe mark in the open position STEP 9 Install the snap retaining ring into the ring groove using snap ring STEP 10 Install the bearing assembly STEP 11 Place two Bellville springs on top of the installed bearing assembly Page 7

8 ASSEMBLY (CONTINUED) Installing Chesterton Bonnet Packing STEP 12 The Chesterton bonnet packing is composed of a five ring set. The bottom and top rings are a square braid of graphite and the three middle rings are solid. Great care should be taken when installing the bonnet packing. Individual rings should be installed one at time. STEP 13 Attach the scale ring (if required to the top of body). The scale ring should only be installed on choke valve body s which are manually operated. STEP 14 After the packing and scale ring is installed, place the bonnet into the body. STEP 15 Torque the bonnet nuts to 12 ft.-lbs. Page 8 Measure the gap between the bonnet and body after the bonnet nuts have been tightened.

9 ASSEMBLY (CONTINUED) Installing the Chesterton Gland STEP 17 The Chesterton gland packing is placed around the fork in the bonnet stuffing box. STEP 18 Install the gland and torque the gland nuts to 48 in-lbs. : Always coat both ends of gland nuts with a copperbased anti-seize lubricant to achieve correct stud tension and corrosion protection. To live load the fork packing, first tighten the gland nuts down without the gland springs to 48 in-lbs. Next remove any opposing gland nuts, place the gland springs (a total of six) in apposing directions on the gland stud. Tighten the gland nuts with springs to 48 in-lbs. Repeat this same procedure with the remaining two gland nuts. STEP 19 Install lever (or mounting hardware) For chokes which will be exposed to over 200 deg. F service, the high temperature paint (Rustoleum V ) shall be applied after testing. The paint must cure a minimum of two hours prior to shipping. Page 9

10 TESTING 1) Steam Choke Valves may be tested in accordance with Valvtechnologies Quality Procedure, VQP ) When performing the seat test, the pressure must be applied on the upstream side. The arrow on the Steam Choke valve (or the label indicating the high pressure end) will indicate the direction pressure should be applied. TROUBLE SHOOTING MALFUNCTION POSSIBLE CAUSE REMEDIAL ACTION Steam Choke Valve Will Not Rotate or Operate Fork Packing Leaking Bonnet Gasket Leaking Steam Choke Valve Disc Leaking 1) Actuator has failed 2) Steam Choke Valve packed with debris 3) Bonnet gap incorrect 1) Gland bolts loose 2) Packing damaged or missing 3) Seal misaligned 1) Bonnet Bolts loose 2) Bonnet gasket damaged 1) Steam Choke Valve not fully closed 2) Debris trapped in Steam Choke valve 3) Disc damaged 1) Replace or repair actuator 2) Cycle & flush Steam Choke valve to remove debris 3) Call Factory 1) Tighten gland bolts 2) Shut down system & replace packing 3) Replace & properly align 1) Tighten bonnet bolts 2) Remove Steam Choke valve from service & replace bonnet gasket 1) Close the valve 2) Cycle & flush to remove debris. Page 10

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