Val-Matic Cam-Centric Plug Valve - Manual (Page 7)

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GEAR ACTUATOR ADJUSTMENT: The standard
gear actuator is provided with factory-set open and
closed position stops. If the valve does not shut off
tight, the stop bolt can be adjusted allowing the plug to
rotate further into the seat. Loosen the locknut, and
turn the closed stop bolt CCW 1 turn at a time (Figure
11). If the valve continues to leak after all of the
adjustment is taken verify the orientation of the valve
during installation. If a tight shut-off can not be
achieved, a larger gear actuator may be required for
the system operating pressure; consult the factory.
FIGURE 11: GEAR ACTUATOR ADJUSTMENT
MAINTENANCE
The Cam Centric ® Plug Valve requires no scheduled
lubrication or maintenance other than regular
exercising and occasional inspection of the plug. The
exercising is achieved by fully opening and closing the
valve to verify smooth operation. If operation is
difficult, it may be necessary to flush sediment from the
valve by opening and closing the valve several times
under flowing conditions.
The recommended interval for exercising is every six
months or annually if the valve is regularly operated.
Over the life of the valve, inspection and some regular
adjustments may be needed as given below.
CLOSED POSITION ADJUSTMENT: The standard
valve is factory-set to seal at the “Actuator Pressure
Ratings” shown on the nameplate for direct and
reverse pressure directions (see Figure 2). Higher
pressure applications may require adjustment of the
closed position stop or a larger actuator; consult the
factory.
If the valve is found to leak in the closed position due
to wear, the plug can be adjusted by loosening the
closed position stop on the actuator and rotating the
plug further into the seat. Because of the eccentric
action of the valve, further rotation will provide
additional interference between the rubber plug surface
and the body seat. Valves that have been in service
for several years may require inspection of the plug for
damage or wear. See the Disassembly Instructions of
this manual.
PACKING ADJUSTMENT: V-type packing is pressure
sensitive and therefore self-adjusting in nature. Over
tightening will destroy both the pressure sensitive
nature of the packing as well as its sealing capabilities.
The packing configuration used in Cam-Centric Plug
Valves follows the guidelines and recommendations of
V-packing manufacturers.
Additional adjustment can be achieved by removing
one or more shims found under the packing follower
(18). If a leak develops, remove one shim (29) from
the underside of the follower (18). An equal number of
shims must be removed from both the left and right
hand sides. Re-tighten the follower bolts (19) and
check for leakage. If the leakage continues, remove
additional shims or replace the packing.
FIGURE 12. PACKING ASSEMBLY
CAUTION: Adjust closed stop bolt for tight
shut-off only. Over adjustment
may cause high operating torques
and damage to the plug.
CAUTION: Open and close the valve slowly to
prevent water hammer.