Flowserve Valtek Mark One K-Bellows Sealed Globe Valves - Manual (Page 6)

Valtek Mark One K-bellows
6
3.4 If the packing has been removed,
replace packing spacer, packing and upper
stem guide (refer to Figure 1).
3.5
Inspect the lower guides for wear or
damage. The lower guides are held in place
by with a press fit. If the guide liner is
damaged or worn, machine out the retainer and
replace the guide liner and retainer.
3.5.1
When the valve is equipped with PTFE
guide liners, the liner can be removed by
deforming the PTFE without removing the
retainer from the housing. Once the liner is
removed, cut the new liner straight up the side.
This will allow the liner to be rolled onto itself
and installed into the guide retainer while the
retainer is still in the housing. Once the liner is
in place it will spring back into place.
3.6
Place the upper guide housing gasket
and then the guide housing onto the plug stem.
3.7
Reattach the plug head by screwing it
onto the plug stem. Do not use anti-seize on
the plug head to plug stem threads. Use a
small tack weld to keep the plug head from
turning off the plug stem.
CAUTION: Although the valve
incorporates an anti- rotation pin, care
should be taken not to put excessive
torque on the plug stem/bellows
assembly. Excessive torque can damage
bellows and/or shear the anti- rotation
pin.
NOTE: Many K- bellows valves use alloy
materials for the materials of
construction. Be careful to match the
correct weld rod with the plug head and
stem material before tack welding them
together.
3.8
Replace the seat gasket, seat ring, seat
retainer, lower guide housing gasket into the
body. Make sure the seat ring spins freely to
assure proper installation.
3.9
Lower the bellows assembly straight
down into the body taking care not to damage
the seating surfaces on the plug and seat ring.
WARNING: Care should be taken not to
damage the bellows or plug and seat
ring seating surfaces when installing the
bellows. Damage to the bellows may
cause faulty operation and/or injury to
personnel.
3.10 Assemble and tighten the body bolting
to finger tight.
3.11
Place the gland flange over the plug
stem and the stem clamp on the actuator stem
and reinstall the actuator assembly by screwing
it onto the plug stem. Hold the plug stem from
turning using the flats on the stem and a
wrench.
3.11.1
On air-to-open valves, screw the
actuator down until there is a 1/32 to 1/16” gap
between the yoke and the bonnet. This should
leave three or four plug stem threads exposed
below the actuator stem to ensure proper
seating.
3.11.2
For correct plug engagement on air-to
open valves, make certain the plug does not
rotate in the body/bonnet assembly and screw
the actuator assembly onto the plug as far as
possible.
CAUTION: Although the valve
incorporates an anti- rotation pin, care
should be taken not to put excessive
torque on the plug stem/bellows
assembly. Excessive torque can damage
bellows and/or shear the anti- rotation
pin.
WARNING: Rotation of the plug while
clamped in the body/bonnet assembly
will damage the bellows seal, which
could cause personal injury.
3.12
Apply air pressure above the piston to
drive it to the bottom of the actuator cylinder.
Without rotating the plug, back the actuator
assembly off of the plug stem until there is
1/32-inch gap between the bottom of the yoke
and bonnet. Then back the actuator assembly
off of the plug stem exactly one complete turn.
This provides the correct seating force.
3.13
Apply air below the actuator piston,
retracting the plug. Install the yoke clamp.
Replace the gland flange bolting and tighten
the stem clamp nut.
3.14
To properly align the seat ring and plug,
first bring the bonnet bolting to finger tightness.
Apply air above the piston to seat the plug in
the seat ring.
NOTE: Step 3.14 applies only to valves
with pneumatic actuators. If a hydraulic
or mechanical actuator is used, return