Model A31A
15
11. Inspect the valve body bore, bearings, bearing
bores, and packing box for damage.
Note
In these instructions, the drive shaft
(with splined end) is called the upper
shaft (key 3). The shaft opposite the up-
per shaft is called the lower (follower)
shaft (key 4).
Installing the Two-Piece Shaft
Key numbers in this procedure are shown in figure 9
unless otherwise indicated.
1. Properly secure the valve on a suitable worktable
so it can not slip, twist, or fall during maintenance. Be
prepared to support the valve disk. Allow for easy ac-
cess to the valve body bore, drive shaft bearing bore
and follower shaft bearing bore.
Note
Replacement disk and shafts are pro-
vided as a matched set and both should
be replaced at the same time.
2. Inspect all parts removed from the valve for wear
or damage. Replace any worn or damaged parts.
Clean the valve body and all parts to be installed with
an appropriate solvent or degreaser. Note: When
installing the bearings, apply lubricant to the outside
diameter of the bearing for ease of installation.
CAUTION
Premature valve failure and loss of pro-
cess control may result if bearings are
improperly installed or are damaged
during installation.
3. When installing the lower bearings (key 4), insert
bearings into the drive shaft bearing bore so one end
is flush with the body bore and the other end is flush
with the interior end of the packing box.
Two bearings are required in the upper shaft and two
bearings in the lower shaft. If using a 14-inch Class
150 valve with metal bearings, four bearings in the
upper and four in the lower shaft will be required.
4. Insert one bearing from the valve body bore into
the follower shaft bearing bore so it is flush with the
valve body bore.
5. Insert the drive shaft into the valve body through
the packing box. Push the drive shaft throught the
bearing. Hold the drive shaft drive bearing (key 24) in
the valve body bore against the opening of the drive
shaft bearing bore. Push the drive shaft through the
bearing bore just enough to hold the thrust bearing.
6. Insert the follower shaft through the bore in the
valve body uncovered by removal of the gasket retain-
er. Hold the follower shaft thrust bearing (key 24) in
the valve body bore against the opening of the follower
shaft bearing bore. Push the follower shaft through the
bearing bore just enough to hold the thrust bearing.
7. Install the valve disk. Place the flat side of the disk
on a flat surface, then move the valve body from its
upright position and suspend the valve body over the
disk so the seal ring/T slot area is facing up. Align the
shaft bores through the disk with the drive shaft and
follower shaft bores. Lower the valve body over the
disk using caution not to dislodge or damage the thrust
bearing s placed on the ends of the shafts.
8. With the valve disk properly positioned in the valve,
push the drive shaft and follower shaft the rest of the
way through the thrust bearings and into the shaft
bores in the valve disk.
CAUTION
To avoid damage to the disk, seal, and
T-slot area, do not force the disk past
the seal or T-slot area. Install the disk
from the opposite side of the valve
body.
9. Align the holes in the shafts with the holes in the
disk.
CAUTION
To avoid damage to the tangential pins,
disk pins, valve disk, or shaft(s) result-
ing from the application of excessive
force, use appropriate care when driving
the pins into the disk hub and shaft(s).
Use the right tool. Do not use excessive
force.
10. Install the appropriate tangential pins, and disk
pins. Use 3 tangential pins that will go through the up-
per shaft and 1 disk pin that will go through the lower
shaft.
11. Refer to
Packing Maintenance and the Anti-Blow-
out Design procedures in this manual to re-install the
packing and anti-blowout design.
