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Instruction Manual
CVS 128PQC
Series Control
Valve
Introduction
Contents
Contained in this manual are installation
instructions, maintenance procedures and parts
information for the CVS 128PQC Control Valve.
Refer to the appropriate manuals for instructions
for the accompanying instrumentation and other
equipment.
Trained or experienced personnel should carry
out operation and installation of all pressure
equipment. If you have any questions regarding
the equipment, contact your CVS Controls
representative.
Description
The CVS Series 128PQC Control Valve body
assembly is suitable for on-off dump valve
service in oil and gas production applications, in
either sweet or sour gas conditions. This valve
is also useful for on-off high-pressure control of
numerous gasses and liquids, and can be used
with materials that are viscous or erosive.
This is a single port valve with unbalanced
stem-guided valve plug, and push- down-to-
close valve plug action. Operated by a Type
128 spring-and-diaphragm actuator, the
assembly can be operated in a normally open or
normally closed application. This setting can be
reversed in the field with minimum disruption
and no additional parts.
Head Office
3900 – 101 Street
Edmonton, Alberta, Canada T6E 0A5
Office: (780) 437-3055
Fax: (780) 436-5461
Website: www.cvs-controls.com
Figure 1: CVS Type 128PQC Control Valve
CVS Type 128PQC is a 1-inch Control Valve,
standard configuration is with a solid pipe plug
threaded into the bottom connection for straight-
through flow. To convert the control valve to
angle flow, the pipe plug can be installed in the
left port as shown in Figure 2. Note: This
configuration from straight-through flow to angle
flow can be achieved in the field.
Flow Charcteristic: Quick Opening with a 45
taper plug.
The CVS Series 128PQC valve is available with
soft-seat, cageless soft seat, or all metal seat
construction. All configurations have push-
down-to-close valve plug action (Figure 2).
The valve plug shuts off against the integral
seat ring in the cage, except in cageless soft-
seat construction, where the shut-off is against
the seat which is cut into the web of the valve
body. Rotation of the valve plug is limited with
the use of a nylon insert in the valve plug
thread.
E-Mail: info@cvs-controls.com
o
Calgary Sales Office
3516 114 Avenue SE
Calgary, Alberta, Canada T2Z 3V6
Office: (403) 250-1416
Fax: (403) 291-9487

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Summary of Contents for CVS Controls 128PQC Series

  • Page 1 If you have any questions regarding through flow. To convert the control valve to the equipment, contact your CVS Controls angle flow, the pipe plug can be installed in the representative. left port as shown in Figure 2. Note: This...
  • Page 2 Warning: Description continued, The leakoff vent must be kept open at all Any process leakage passing through the times. Flammable or other hazardous fluids packing is permitted to escape through a leakoff should be vented into an open, well-ventilated vent which passes through the packing box and area to prevent fire or explosion.
  • Page 3: Installation

    Installation The versatility of this valve allows for installation in any orientation, with the standard method Warning: being with the actuator above the body. Service conditions must not exceed the limits Standard orientation is best when an angle body shown on the valve nameplate, or those or angle configuration has been specified.
  • Page 4: Maintenance

    1000 1000 1000 Open 1000 1000 1000 Valve Fail 12.7 1000 Close 1000 1000 1000 Close Soft 1000 1000 1000 1000 Valve 12.7 1000 1000 1000 1000 Fail Close Open Valve 12.7 1000 * Contact CVS Controls for pressure drop...
  • Page 5 Replacing Packing and Trim continued, 9. Fix the valve plug onto the stem, rotating the plug until the shoulder makes snug contact 3. Accessible areas should be cleaned at this with the stem. No further tightening is stage, and all necessary maintenance necessary.
  • Page 6 Changing Main Spring Range Reversing Action or Replacing Actuator Parts Unless otherwise indicated, refer to Table 3 for parts listings for replacement packing and trim Unless otherwise indicated, refer to Table 3 for assembly, Figure 3 for packing and trim parts listings for replacement packing and trim assembly key numbers and Figure 5 for control assembly, Figure 3 for packing and trim...
  • Page 7: Parts Ordering

    Please valve action: refer to that number when ordering parts or 8.1. Fail–close action: install the following contacting your CVS Controls Sales parts: flat washer (Key 33), diaphragm Representative. Individual parts numbers are (Key 35), diaphragm plate (Key 34), listed as follows.
  • Page 8 Table 3: Replacement Packing and Trim Assembly Part Numbers TFE V-Ring Packing, Nitronic 50 SST Valve TFE V-Ring Packing and Heat-Treated 440C SST Port Diameter Plug and Cage, and Inconel X750 Packing Valve Plug and Cage Spring CVS Type 128PQC CVS Type 128 PQC 17-7PH SST Packing Spring CVS15A2611X012...
  • Page 9 CVS Type 128PQC Control Valve: Fail-Closed with Cage-Style Metal Seat and Single TFE-V-Ring Packing CVS Design 128PQC Cageless Soft-Seat Detail Fail-Open Actuator Detail Figure 5: Typical CVS Series 128PQC Control Valve Assembly...
  • Page 10: Parts List

    Parts List Description Part Number Upper Diaphragm Casing, Steel CVS24A8816X012 Spring Plate, Zinc Plated Steel CVS14A8819X012 Vent Assembly CVS1C8937000A2 Washer, Steel CVS1A742328992 Indicator Bushing, 316 SST CVS13A2323X012 Indicator Cover, Plastic CVS15A1580X012 Travel Indicator Disc Nut, Plastic CVS1F730506992 Machine Screw, SST CVS14A8818X012 Indicator Fitting SST CVS15A0726X012...
  • Page 11: Flow Coefficients

    PRODUCT BULLETIN – CVS 128PQC Flow Coefficients QUICK OPENING PORT MAXIMUM DIAMETER TRAVEL Valve Opening— Percent of Total Travel VALVE SIZE mm Inches mm Inches Globe Valve—Flow Up 6.35 .566 1.14 1.38 1.38 .654 1.32 1.60 1.60 .539 .694 .539 .539 9.53 .828...
  • Page 12 E-Mail: info@cvs-controls.com CVS Controls Ltd. strives for the highest levels of quality and accuracy. The information included in this publication is presented for informational purposes only. CVS Controls Ltd. reserves the right to modify or change, and improve design, process, and specifications without written notice.

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