Instruction manual

A31A Valve
Instruction Manual
Form 5291
March 2008
11
Usually, packing leakage can be eliminated by
merely tightening the hex nuts (key 15) located
above the packing follower (key 12) while the valve
is in the pipeline. However, if leakage continues, the
packing must be replaced.
For PTFE ENVIRO-SEAL packing system, refer to
instruction manual, ENVIRO-SEAL Packing Systems
for Rotary Valves  Form 5305 (see figure 10).
CAUTION
Never use a wrench or pliers on the
keyed (upper) shaft (key 3). A damaged
shaft could cut the packing and allow
leakage.
1. Before loosening any parts on the valve, release
the pressure from the pipeline. Then, remove the
hex nuts (key 15) and lift off the packing follower
(key 12).
2. Remove the hex jam nuts (key 17) and the
anti-blowout flange (key 10). Remove the packing
follower (key 12). Refer to figure 7 for details of the
anti-blowout protection parts.
The packing is now accessible.
3. Use a packing extractor to remove packing. Insert
the corkscrew-like end of the tool into the first piece
of packing and pull firmly to remove the packing.
Repeat this process until all packing parts have been
removed.
CAUTION
Be careful when cleaning the packing
box. Scratches to the upper shaft
(key 3) or inside diameter of the
packing bore might cause leakage.
4. Before installing new packing, clean the packing
box.
5. Install new packing one ring at a time, using the
packing follower as a driver. If using split-ring
packing, stagger the splits in the rings to avoid
creating a leak path.
6. Reinstall the packing parts. Refer to figure 10 for
the sequence of packing parts.
Removing the Valve
1. Disconnect any operating lines providing air
pressure, electric power, or a control signal to the
actuator. Be sure the actuator cannot suddenly open
the valve. Vent the power actuator loading pressure.
2. Use bypass valves or completely shut off the
process to isolate the valve from process pressure.
Relieve process pressure on both sides of the valve.
Drain the process media from either side of the
valve.
CAUTION
Damage to the valve disc can occur if
the disc is not closed when the valve
is being removed from the pipeline. If
necessary, stroke the actuator to place
the disc in the closed position while
removing the valve from the pipeline.
3. Loosen the flange bolting that holds the valve.
Make sure the valve cannot slip or twist while
loosening and removing the bolting.
4. Before removing the valve from the pipeline,
make sure the valve disc is closed. Removing the
valve with the disc open could cause damage to the
disc, piping, or pipe flanges.
5. After removing the valve from the pipeline, move
the valve to an appropriate work area. Always
support the valve properly.
6. When valve maintenance is complete, refer to the
Installation procedures in this manual.
Seal Maintenance
Note
For larger valves, it is possible to
replace the seal (key 5) while the
actuator is mounted to the valve and
can be accomplished by cycling the
valve to 90 degrees open.
Key numbers in this procedure are shown in figure 9
unless otherwise indicated.
1. After removing the valve from the pipeline,
remove the manual or power actuator. Manually
rotate the upper shaft (key 3) counterclockwise until
the disc has moved a full 180 degrees away from the
closed position.