Instruction manual

A31A Valve
Instruction Manual
Form 5291
March 2008
15
This adjustment is necessary to be certain that the
actuator output torque is fully absorbed by the
actuator travel stop or by the actuator. The
internal travel stop in the valve body should not
absorb any of the actuator torque.
CAUTION
When using an actuator, the actuator
travel stop (or actuator travel, for
actuators without adjustable stops)
must be adjusted so the disc stop in
the valve does not absorb the output
of the actuator. Failure to limit the
actuator travel as described in the
Adjusting the Actuator Travel Stops or
Travel steps can result in damage to
the valve, shaft(s), or other valve
components.
10. The final seating of the retaining ring screws can
now be done. For the screw torque values, refer to
table 6.
Anti-Blowout Design, Packing, Valve
Shaft(s), Disc, and Bearing
Maintenance
Note
The A31A valve has a two-piece shaft.
In these procedures, the drive shaft
(with keyed end) is called the upper
shaft (key 3). The shaft opposite the
upper shaft is called the lower
(follower) shaft (key 4).
CAUTION
When using an actuator, the actuator
travel stop (or actuator travel
adjustment, for actuators without
adjustable stops) must be adjusted so
the disc stop in the valve does not
absorb the output of the actuator.
Failure to limit the actuator travel as
described in the next step can result in
damage to the valve, shaft(s), or other
valve components.
CAUTION
When removing the actuator from the
valve, do not use a hammer or similar
tool to drive the lever off the valve
shaft. Driving the lever or actuator off
the valve shaft could damage the valve
internal parts.
If necessary, use a wheel puller to
remove the lever or actuator from the
valve shaft. It is okay to tap the wheel
puller screw lightly to loosen the lever
or actuator, but hitting the screw with
excessive force could also damage
internal valve parts.
Key numbers in this procedure are shown in figure 9
unless otherwise indicated.
1. Remove the valve from the pipeline. Remove the
actuator from the valve.
WARNING
Avoid personal injury or property
damage caused by the impact of a
falling or tipping of a large valve.
Support large valves during
maintenance.
CAUTION
Never use a wrench, pliers, or similar
tool to turn the upper shaft. A
damaged shaft can cut the packing
and allow leakage.
Note
It is not necessary to remove the
retaining ring and valve seal when
removing the shaft(s) and disc.
2. Properly secure the valve on a suitable worktable
so it cannot slip, twist, or fall during maintenance.
3. Removing the Anti-Blowout Design:
a. For PTFE or Graphite Packing: Remove the
hex nuts (key 15) and pull off the packing follower
(key 12). Remove the hex jam nuts (key 17) and
the anti-blowout follower (key 10). Remove the
anti-blowout gland (key 12). Also, see figure 7.
b. For ENVIRO-SEAL Packing System:
Remove the hex nuts (key 101), the packing