Flowserve Valtek Mark 10 Survivor Control Valves - Manual (Page 15)

15
Valtek Mark 10 Survivor Control Valves FCD VLENIM0036-05 – 07/09
flowserve.com
5.1.5. To inspect the plug, remove it by loosening stem clamp and gland flange and screw it out
of actuator stem. Pull the plug carefully through the packing box.
CAUTION:
a
To avoid scoring the guides and plug stem, follow the above procedure exactly.
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 some galling on the plug may
occur.
5.1.6. If seat surfaces are metal and need re-machining, both surfaces on the plug and seat
ring must be reworked. The seat angle on the plug is 30 degrees; seat ring, 33 degrees.
Lapping will not be necessary if proper assembly procedures are followed.
CAUTION: a If re-machining metal surfaces, protect stem during turning. Insure concentricity of
the seat surface with the plug stem (or outside diameter of seat ring, if machining seat).
5.1.7. Remove the actuator from the bonnet subassembly, by first removing the gland flange and
then removing the yoke bolting/clamp. Finally disconnect the bonnet from the actuator.
5.1.8. Remove the wiper set assembly, if supplied. The packing can also now be removed from
the packing box using an appropriate sized dowel to push it out.
CAUTION:
a
Do not score or gall the packing box bore or stem guides.
WARNING:
c
For valves equipped with separable end flanges, use extreme care to not over
machine body gasket surfaces. Removing excessive body material could cause failure of the
separable flange lip, causing end gasket leakage and failure of the valve.
CAUTION:
a
When using separable end flanges and spiral wound gaskets, use gaskets with outer
backup rings. Failure to do so could result in excess stress in some applications.
NOTE: To prevent flanges from dropping off during shipping, a tack weld or stainless steel rivet has
been installed behind the end flanges.
5.2. Reassembling the Valve Body
Survivor valves are specifically engineered for each application. Before reassembling, consult the
factory for packing and wiper set configuration.
5.2.1. Reinstall the packing, guides and packing spacers per factory instructions. If wiper rings
are provided, install per the factory drawings. Lubrication of the packing is recommended.
See Table I for suggested lubricants. Applying lubrication to the packing at this stage will
ease reassembly.
5.2.2. Insert the plug into the bonnet, being careful to not score or gall either. Be careful to
not pinch or score the wiper set. Clamp the bonnet vertically into a vise with the plug
supported on a soft surface.
CAUTION:
a
Be careful to not strike the plug head against any object.
5.2.3. Insert the packing assembly according to configuration specified by the factory. Make
sure at least
1 /
8
-inch is left at the top of the packing box for the top stem guide to enter.
Different spacer lengths permit a wide variety of packing configurations, such as twin seal
and vacuum-pressure packing. Where Grafoil guides are used, the Grafoil liners should be
replaced each time the valve packing is replaced. Under no circumstances should the valve
be rebuilt without Grafoil liners in the guides.