Instruction manual

A31A Valve
Instruction Manual
Form 5291
March 2008
17
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.
Note
Replacement disc and shafts are
provided 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
process control may result if bearings
are improperly installed or are
damaged during installation.
3. When installing the lower bearings (key 4), insert
one or more bearings into the lower shaft bearing
bore so it is flush with the body bore.
The number of bearings required changes with valve
size and construction. Two bearings are required in
the upper shaft and two bearings in the lower shaft.
If using an NPS 14 CL150 valve with metal bearings,
four bearings in the upper and four in the lower shaft
will be required.
4. Hold the lower shaft thrust bearing (key 24) in the
valve body bore against the counterbore of the lower
shaft bearing bore. Push the lower shaft into the
bearing bore just enough to hold the thrust bearing.
5. When installing the upper bearing (key 7), insert
one or more bearings into the upper shaft from the
body bore into the bearing bore below the packing
box. Use caution to prevent damage to the bearing.
CAUTION
Use caution to prevent damage to the
bearing when installing the upper
bearing in the previous step.
6. Hold the upper shaft thrust bearing (key 24) in the
valve body bore against the counterbore of the
upper shaft bearing bore. Push the upper shaft
through the packing box side into the bearing bore
just enough to hold the thrust bearing.
7. When installing the lower bearing (key 4), insert
one or more bearings into the lower shaft bearing
bore so it is flush with the body bore.
8. Insert the lower shaft through the bore in the
valve body uncovered by removal of the gasket
retainer. Hold the lower shaft thrust bearing (key 24)
in the valve body bore against the counterbore of the
lower shaft bearing bore. Push the lower shaft into
the bearing bore just enough to hold the thrust
bearing.
CAUTION
To avoid damage to the disc, seal, and
T-slot area, do not force the disc past
the seal or T-slot area. Install the disc
from the opposite side of the valve
body.
9. Place the flat side of the disc on a flat surface
and insert wooden blocks to raise the disc
approximately 50.8 mm (2 inches) from the
worktable surface. Then, suspend the valve body
over the disc so the seal/T-slot area is facing up.
Align the shaft bores through the disc with the upper
shaft and lower shaft bores. Lower the valve body
over the disc using caution not to dislodge or
damage the thrust bearings placed on the ends of
the shafts.
10. With the disc (key 2) properly positioned in the
valve body (key 1), push the upper shaft and lower
shaft the rest of the way through the thrust bearings
and into the shaft bores in the valve disc.
11. Align the holes in the shafts with the holes in the
disc.
CAUTION
To avoid damage to the tangential
pins, disc pins, valve disc, or shaft(s)
resulting from the application of