General Twin Seal O&M Manual 2008

PROCESS VALVES

Installation, Operation and Maintenance Manual

GENERAL TWIN SEAL

GENERAL VALVE
Installation, Operation and Maintenance Manual

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GENERAL TWIN SEAL / IOM-GEN-TWINSEAL

PROCESS VALVES

TABLE OF CONTENTS TWIN SEAL VALVES Installation ............................................................... 1 Operation................................................................. 2 Series 400, 800 & 900 Integral Bushing/Retained Ring Gland ...................... 3 Integral Bushing/Bolted Gland ................................... 3 Bushings/One Gland ................................................. 4 Bushings/Two Glands ............................................... 4 Bearings/Dual Retention ........................................... 5 Bearings/Internally &Externally Retained ................. 6 Bearings/Internally Retained w/Two Glands .............. 6 Series 8800 ............................................................... 7 OPERATORS Model 375H ............................................................... 8 Model 500H & 625H .................................................. 9 Model 376G & 501G ................................................ 10Model 625G & 751G & 755G .................................. 12 Model 1261G & 1261-7G ........................................ 14 Model 1276G ........................................................... 16 Model 1500G ........................................................... 18 BLEEDS The DTR System Explained .................................... 20 MISCELLANEOUS Operation & Maintenance....................................... 22 Parts ........................................................................ 22

© Cameron’s Valves & Measurement Group Revised 11/07-NP-3M IOM-GEN-TWINSEAL

Installation, Operation and Maintenance Manual

GENERAL TWIN SEAL / IOM-GEN-TWINSEAL

PROCESS VALVES

INSTALLATION ORIENTATION
GENERAL TWIN SEAL valves may be installed in any position.

FLANGEFASTENERS
Certain GENERAL TWIN SEAL flange holes are drilled and tapped, when there is no possibility of fitting a hexagonal nut behind the flange. The quantity and size of these tapped holes is shown in Table 2. Capscrews or stud bolts may be used in these holes.

FLOW DIRECTION
The GENERAL TWIN SEAL design is symmetrical. Flow shut-off is achieved equally on both sides of the plugindependent of flow direction. Note: The use of a Differential Thermal Relief (DTR) as described on pages 20/21 does result in a preferred flow direction.

TABLE 2
Valve ASME Number of Size Class Tapped Holes inch 150 per Flange 6 150 4 8 150 4 8 300 4 10 150 4 10 300 4 12 150 4 12 300 4 14 150 8 14 600 4 16 150 8 18 150 8 24 150 4 24 600 8 28 150 6 28 300 6 30 150 6 Thread UNC 3/4" - 10 3/4" - 10 7/8"- 9 7/8" - 9 1" - 8 7/8" - 9 1 1/8" - 8 1" - 8 1 3/8" - 8 1" - 8 1 1/8" - 8 1 1/4" - 8 1 7/8" - 8 1 1/4" - 8 1 1/4" - 8 1 1/4" - 8 Length Required (inch) Cap Stud Screws or Bolts 2 1/4 3 1/4 2 1/4 3 1/4 3 4 1/4 2 1/4 3 1/4 3 4 1/4 2 1/4 3 1/2 3 1/2 5 2 1/2 4 3 3/4 4 3/4 2 1/2 3 3/4 3 4 1/4 3 1/4 4 3/4 5 1/4 6 3/4 3 1/4 4 1/2 3 1/4 4 1/2 3 1/4 4 1/2

CLEARANCE FOR REPAIR
For easy repair, spaceshould be allowed below the valve for removal of the lower plate and withdrawal of the seating slips. See Table 1 for dimensions. Sufficient clear space is required above the GENERAL TWIN SEAL valve, to allow free movement of the position indicator flag and for removal of the operator mechanism.

TABLE 1
Clearance required below standard ported valves for Slip Removal.
Minimum Clearance ValveSize inch 6" 8" 10" 12" 14" 16" 18" 20" 24" 28" 30" ASME Class 150 9" 13" 15" 17" 19" 22" 23" 26" 28" 30" 30" ASME Class 300 9" 11" 13" 16" 15" 19" 13" 14" 17" 12" 28" ASME Class 600 10" 12" 8" 10" 10" 14' XXXX 14" 12" XXXX XXXX ASME Class 900 8" 10" 10" 10" XXXX XXXX XXXX XXXX XXXX XXXX XXXX

GEAR HOUSING ORIENTATION
On gear-operated models the gear housing and associated hand wheel may be...