Type A31A
13
12. Use an appropriate tool (such as a feeler gauge)
and position the disk from 0.001 to 0.030 inch (0.03 to
0.76 mm) away from the internal stop in the valve
body.
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 actua-
tor torque.
Cryogenic Seal Installation
Unless otherwise indicated, key numbers and part
names are listed in figure 8.
A maintenance kit with installation tools is available
through your Fisher Controls representative or sales
office.
1. Locate the replacement seal ring (key 5) and note
the shape of the ring. The ring is wider across one
edge diameter and narrower across the other edge
diameter. Also, note the wide groove around the out-
side circumference. If an aluminum backup ring is pro-
vided, fit this over the back of the seal ring (matching
seal and backup ring angles) prior to installation in the
valve.
2. Install the seal ring (key 5) in the valve body by first
placing the wider outside diameter of the seal ring into
the T-slot area of the valve body as shown in figure 6.
3. Once the seal ring has been fully installed into the
body T-slot, the retaining ring gasket can be installed.
This gasket is a thin graphite material. Use extreme
care to avoid damaging the gasket while punching one
initial screw hole through the gasket for alignment.
4. Install the retaining ring, and align the screw holes
in the retaining ring with the holes in the valve body.
Install the first retaining ring screw through the
punched hole in the retaining ring gasket. Install the
other retaining ring screws by pushing them through
the graphite gasket and threading them into the valve
body.
5. Tighten the retaining ring screws just enough to
eliminate any movement of the retaining ring. Do not
over-tighten the retaining ring screws.
WARNING
Avoid personal injury or property dam-
age caused by the impact of a falling or
tipping valve. Support large valves dur-
ing maintenance.
6. To complete this step, stand the valve up. Support
the valve securely using methods appropriate for the
valve size. If a vise or other clamps are being used,
make certain the flange gasket sealing area of the
valve body is not damaged.
7. Manually rotate the drive shaft (key 3) to turn the
disk clockwise to meet the seal ring.
8. Place a piece of rubber, or other soft material, be-
tween the disk and internal travel stop to protect the
disk. With a rubber mallet, tap the disk until it contacts
the internal travel stop. When the disk makes contact
with the stop, manually rotate the disk counterclock-
wise back out of the seal ring to a 90-degree open
position.
9. The final seating of the retaining ring screws can
now be done. For the screw torque values, refer to
table 6.
10. Repeat steps 7 and 8 two more times.
Note
When attaching the actuator to the
valve, make sure the valve disk is not in
contact with the internal travel stop. The
valve disk should be positioned from
0.001 to 0.030 inch (0.03 to 0.76 mm)
away from the internal stop in the valve
body.
11. Use an appropriate tool (such as a feeler gauge)
and position the disk from 0.001 to 0.030 inch (0.03 to
0.76 mm) away from the internal stop in the valve
body.
This adjustment is necessary to be certain that the
actuator output torque is fully absorbed by the ac-
tuator travel stop or by the actuator. The internal
travel stop in the valve body should not absorb any of
the actuator torque.
