Flowserve Valtek Mark One K-Bellows Sealed Globe Valves - Manual (Page 5)

Valtek Mark One K-bellows
5
bolting. Once the yoke clamps are off remove
the air from the actuator. This will cause the
yoke and bonnet to separate. Hold the plug
stem with a wrench and turn the actuator
counter clockwise until it is free. Take care not
to turn the plug stem as this will damage the
bellows.
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: Heavy assemblies may require a
hoist. A lifting ring is provided on most
actuators for this purpose; otherwise,
lift by the yoke legs using lifting straps
and a hoist.
2.2
Loosen and remove the bonnet flange
bolting. Remove the bonnet, and anti-rotation
pin. The anti-rotation pin is small and often
becomes lost at this point. Find a place for
the pin where it will not be lost before
reassembly.
WARNING: If there has been a bellows
failure, process fluids may be trapped in
the packing box; therefore, be extremely
cautious when removing the packing box
bolting and packing.
2.3
Remove the upper stem guide, packing
and packing spacer from the bonnet.
2.4
Loosen and remove body bolting nuts.
Leave the body studs in the body unless they
need to be removed.
2.5
Remove the entire bellows seal
assembly and bellows housing by lifting them
straight out of the body.
NOTE: Heavy bellows assemblies may
require a hoist. Use lifting straps or
lifting rings as needed.
2.6 Place the bellows assembly of the valve
in a safe working location or on the bench,
taking care to protect the seating surfaces on
the plug.
2.7 Remove the seat retainer, seat ring, and
seat gasket from the body.
2.8
Carefully grind off the tack weld
between the plug head and the plug stem.
Using the flats on the plug head and the stem,
remove the plug head from the stem, taking
care not to damage the seating surfaces of the
plug head.
2.6
Remove the guide housing, bellows
housing and gaskets from the bellows
assembly.
2.7
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. 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.
WARNING: The lower guides are
exposed to process fluid and fluid may
still be trapped into the voids in this
area. Be extremely cautious while
removing the lower guides.
NOTE: The bellows assembly should not
be taken apart. If the bellows has
failed, the entire cartridge should be
replaced.
3. REASSEMBLY OF K-
BELLOWS VALVES
To reassemble the K-Bellows valve, refer to
Figure 1 and proceed as follows:
3.1
Check metal bellows for signs of wear
or damage. If the bellows shows signs of
fatigue or cracking, obtain a replacement before
reassembling and operating the valve. Make
sure all gasket surfaces are clean and free of
damage.
3.2
Replace the lower upper flange gasket
and insert the bellows assembly into the
bellows housing.
3.3
Place the top upper flange gasket onto
the upper bellows flange. Replace the anti-
rotation pin, bonnet, bonnet flange and bonnet
flange bolting. Take care not to scratch the
plug stem during assembly. Keep the bonnet
flange bolting loose at this point. Align the
bonnet so that the tell-tale port faces the back
of the valve, opposite the positioner.