Instruction manual

A31A Valve
Instruction Manual
Form 5291
March 2008
16
follower (key 102), jam nuts (key 17),
anti-blowout flange (key 10), and the spring pack
assembly (key 103). See figure 10.
4. Remove the packing from around the upper shaft.
5. Remove the tangential pins or disc pins. Locate
the pins (key 25) in the upper shaft (key 3) and the
pin in the lower shaft (key 4), if the valve has a
two-piece shaft.
a. If a maintenance kit is available, use the pin
extractor to remove the disc pins. Select the
correct size pin extractor tip with screws of proper
thread size to match the thread size in the disc
pins. If you do not have a kit, see steps c and d
below.
b. Screw the pin extractor tip into the pin as far
as possible. With an upward, straight sliding
motion, pull out the pin. Repeat the same
procedure for the other pins.
c. You can use a threaded rod with an
appropriate spacer (tube) and nut as an extractor
tool. If you use a threaded rod, choose a rod with
threads that fit the inside thread of the pins. The
rod should extend several inches above the disc
when it is screwed into a pin.
d. After screwing the rod into the pin, slide the
spacer over the rod and pin. Thread a nut onto
the rod and tighten it. As you tighten the nut, the
nut will drive the spacer against the disc. The
increasing force will draw the pin from the disc.
6. The gasket retainer (key 20) on the side of the
valve opposite the upper shaft must be removed
before removing the lower shaft.
Remove the hex head bolts (key 23) and
lockwashers (key 22) from the gasket retainer and
remove the gasket retainer and gasket (key 21) to
expose the end of the lower shaft.
7. Before removing the lower shaft (key 4), be sure
the valve disc is properly supported. Pull the lower
shaft from the valve body. Use a shaft extractor
screwed into the puller hole in the end of the lower
shaft.
8. Before removing the upper shaft (key 3), be sure
the valve disc is properly supported. Pull out the
upper shaft (key 3) by hand-pulling or by using a
shaft extractor screwed into the end of the shaft.
CAUTION
To avoid damage to the disc, seal, and
T-slot area, do not force the disc past
the seal or T-slot area. Remove the
disc from the opposite side of the
valve body.
Note
Both the upper shaft and the lower
shaft have a thrust bearing (key 24)
between the disc and the bearings (key
7). The thrust bearing is located
outside of the bearing bore which
holds the bearings. Use care when
removing the valve disc to avoid loss
of or damage to the thrust bearings.
9. After removing the shaft(s), remove the disc. Do
not force the disc past the seal or T-slot area. Collect
the thrust bearings.
10. Remove the bearings (key 7). Using a suitable
punch or puller, drive or pull the bearings into the
valve body bore from the upper shaft bearing bore.
Remove the bearing from the lower shaft bearing
bore.
11. Inspect the valve body bore, bearings, bearing
bores, and packing box for damage.
Installing the Two-Piece Shaft
Note
In these instructions, 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).
Key numbers in this procedure are shown in figure 9
unless otherwise indicated.
1. Properly secure the valve on a suitable worktable
so it cannot slip, twist, or fall during maintenance. Be
prepared to support the valve disc. Allow for easy
access to the valve body bore, drive shaft bearing
bore and follower shaft bearing bore.