McCANNALOK CRYOGENIC VALVE
Installation, Operation and Maintenance Manual
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contained herein shall not be copied, transferred, conveyed, or displayed in any manner that would
violate its proprietary nature without the express written permission of Bray International, Inc.
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11.0
FIELD ADJUSTMENTS
11.1
Stem Seal Leakage
11.1.1
Should leakage occur at the stem seals, it may be stopped by
retightening the gland retainer nuts to the values specified in Table 4.
NOTICE
Do not overtighten gland nuts, as this may cause increased operating torque and
improper valve operation or closure.
11.1.2
If the leakage cannot be stopped by this action, the stem seals require
replacement.
11.2
Adjusting Valve Closure
11.2.1
Valves with gear actuators or electric/pneumatic actuators may require
adjustment of the travel stops in the actuator to properly close the
valve for tight shut off. The following procedure should be followed
to set travel or limit stops. (It is recommended that the valve must be
removed from line for this procedure.)
NOTICE
The valve has a positive travel stop to ensure valve disc (2) cannot be over
closed.
11.2.2
Loosen the “close actuator” stop screw completely to permit proper disc
(2) positioning. Close the valve until the disc (2) touches the valve body
(1) positive travel stop. Adjust and lock down the close actuator stop
screw while the disc (2) is in this position. Open and close the valve to
visually check that the valve opens and closes to the correct position.
11.2.3
The valve disc (2) is at the full open position when the disc (2) is
perpendicular to the body (1). Set the “open” actuator stop for this
position.
CAUTION
Do not allow the valve to over-open as this may damage the disc seating surfaces
by hitting body (1) or attached piping.
11.2.4
For other power actuators, consult the manufacturer’s instructions for
setting travel stops, as these vary with actuator model and type.
