7
b. Phoenix III Seal: This seal is bidirectional. For best performance, high pressure at the closed position should be
applied to the back (waterway side) of the disc.
c. NPS 2 Seal: The preferred direction of installation is with high pressure at the front (retaining ring side) of the
disc. Reverse shutoff is permissible at lower pressure (see specifications table).
Installing the Valve in the Pipeline
WARNING
The edges of a rotating disc have a shearing effect that may result in personal injury. To help prevent such injury, stay clear
of the disc edges when rotating the disc (figure 4).
CAUTION
Damage to the disc (key 3, figure 12) sealing surfaces may occur if the disc is not closed when the valve is being installed or
removed from the pipeline. If necessary, provide a loading pressure to the actuator temporarily to retain the disc in the
closed position while installing or removing the valve from the pipeline.
1. For Fail-Open Actuators: It will be necessary to provide a temporary loading pressure to the actuator diaphragm to
move the valve disc to the closed position. Observe the above Warning when closing the valve. If a loading pressure
is required, use caution when working with the valve. If the loading pressure is disconnected, the disc will open
rapidly.
2. With the disc in the closed position, install line flange gaskets, and insert the valve between the pipeline flanges.
WARNING
If spiral wound gaskets are to be used with an NPS 3 or 4 CL150 or 300 single flange valve, special spiral wound gaskets
conforming to the dimensions listed in table 5 MUST be used. Improperly sized gaskets may increase the likelihood of 1)
excessive seat leakage, 2) damage due to contact with valve internals, and 3) external leakage; which may result in
personal injury due to a sudden increase or decrease of pressure within -- or release of pressure from -- the pipeline. The
special dimension spiral wound gaskets can be obtained from your local spiral wound gasket vendor.
The remaining single flange valve sizes (NPS 6 through 12) and all wafer style valves (NPS 2 through 12) use the standard
size spiral wound gaskets. Only the single flange valves in the sizes and pressures listed in the table above require special
spiral wound gaskets.
Select the appropriate gaskets for the application. Flat sheet, spiral wound (NPS 6 through 12), or other gasket types
made to ASME 16.5 group or a user's standards can be used for A41 valves depending on the service conditions and
applications.
3. Install the flange studs:
Note
Lubricate line flange studs or bolts before inserting into flanges. If necessary, provide additional support for the control valve
assembly because of its combined weight.