Flowserve Valtek Mark One K-Bellows Sealed Globe Valves - Manual (Page 7)

Valtek Mark One K-bellows
7
the plug to the mid- stroke position and
proceed to tighten.
WARNING: Failure to return the plug to
the mid- stroke position (mechanical or
hydraulic actuators only) will cause
damage to the actuator and/or the valve
during the bonnet tightening sequence.
This is due to the inability of most
mechanical/hydraulic actuators to
accommodate the 1/16- inch back driving
during the tightening sequence.
3.15
With the plug in the extended (or
closed) position, tighten two opposing bonnet
flange nuts 1/6- turn (one flat). Tighten each
bonnet bolt in this manner until the upper
flange gaskets are compressed and the bonnet
and bellows housing are seated metal-to-metal.
3.16
With the plug in the extended (or
closed) position, tighten two opposing body
nuts 1/6- turn (one flat). Tighten each bonnet
bolt in this manner until the guide housing
gaskets are compressed and the bellows
housing and body are seated metal-to-metal.
CAUTION: Under- tightening may not fully
compress the gaskets, which may cause
leakage. Over- tightening may damage
interior parts. Tighten only to the point
that metal- to- metal seating occurs.
3.17
Remove air from the actuator. Adjust
the positioner cam and stem clamp according
to instructions contained in the appropriate
positioner maintenance bulletin. Then adjust the
stroke plate to indicate proper air-action (air-to-
open valves should be adjusted so the stem
clamp points to “closed” on the stroke plate;
air-to-close valves should point to “open”).
3.18
Install the packing box bolting. Packing
box bolting should be slightly more than finger
tight when Teflon packing is used. Replace the
tell-tale plug. Replace the anti-rotation warning
tag.
CAUTION: Do not over- tighten packing.
Over- tightened packing can cause high
stem friction and excessive packing
wear, which may impede stem
movement.
3.19 Stroke the valve and check for smooth,
trouble-free operation.