Flowserve Valtek Mark 100 Control Valve - Manual (Page 7)

Flow Control Division
Mark 100
FCD FCAIM0100-02 Mark 100 Installation, Operation and Maintenance Instructions 7
6 Valve Disassembly
and Reassembly
6.1 Disassembling the Body
To disassemble the valve body, refer to Figure 1 and 2 then proceed
as follows:
c WARNING: Depressurize line to atmospheric pressure and
drain all fluids before working on the valve. Failure to do so
can cause serious injury.
1. Fully retract the plug until the stem clamp indicator points to the
open position.
2. Remove the bonnet flange bolting and lift the actuator, bonnet
and plug out of the valve body.
c WARNING: Danger exists in removing the actuator,
bonnet and plug, especially if PTFE plug seals are used.
The sleeve may stick to the plug and fall during disas-
sembly, causing possible serious injury and damage
to the valve or nearby equipment. If sleeve is observed
sticking to the plug, steps 3–5 should be consulted.
a CAUTION: Heavy actuators may require a hoist. Lift the
actuator with the yoke legs using a lifting strap and a
hoist. Great care should be taken to lift the actuator and
plug straight out of the body to avoid damage to the
plug and seat.
3. If the sleeve is observed sticking to the plug during removal,
fully extend the plug by applying air above the piston, allowing
the sleeve to remain in the body and the bonnet to rise above
the body.
4. In the gap between the top of the sleeve and the bottom of the
bonnet, place wooden blocking of equal thickness in at least
three places. The wooden blocks must not extend in far enough
that they interfere with plug movement. The plug must be al-
lowed to stroke up to the bonnet.
5. By applying air below the piston, retract the plug until the plug
head is freed from the sleeve. Once the plug is free from the
sleeve, remove the plug and bonnet assembly from the body.
6. Lift the sleeve out of the valve body using lifting points on the
top of the sleeve.
7. Remove cage, seat ring and gaskets from the valve body.
Figure 2: Cutaway Drawing
8. Remove the plug seals from the plug head.
9. Check to see the seating surfaces on both the seat ring and
plug are free of damage to ensure tight shutoff. Make sure the
gasket surfaces on the seat ring, bonnet and body are clean and
undamaged. Inspect the pressure balanced sleeve for scratches
or other damage.
10. Loosen the stem clamp and gland flange. Remove the yoke bolts.
a CAUTION: If a rubber bellows is attached to the gland
flange, the gland flange must be removed prior to
removing the actuator.
11. Turn the actuator off the plug and bonnet without allowing the
plug to rotate within the bonnet. Pull the plug carefully through
the packing box. Inspect the plug stem for damage or scoring.
NOTE: With air-to-close, fail-open valves, it may be necessary
to apply a small amount of air to the top of the actuator to move
the plug away from the bonnet. Otherwise, plug galling may
occur.
a CAUTION: To avoid scoring guides and plug stem, fol-
low the above procedure exactly.