Type A31A
11
CAUTION
Damage to the valve disk, piping or pipe
flanges can occur if the disk is not
closed when the valve is being removed
from the pipeline. If necessary, stroke
the actuator to place the disk in the
closed position while removing the
valve from the pipeline.
3. Loosen the flange bolting that holds the valve.
Make sure the valve cannot slip or twist while loosen-
ing and removing the bolting.
4. Make certain the valve disk is closed and remove
the valve from the pipeline. Support the valve properly
and move the valve to an appropriate work area.
Removing/Installing the Seal Ring
Unless otherwise indicated, key numbers and part
names are listed in figure 8.
Note
For larger valves, it is possible to re-
place the seal ring (key 5) while the ac-
tuator is mounted to the valve and can
be accomplished by cycling the valve to
90 degrees open.
1. After removing the valve from the pipeline, remove
the manual or power actuator. Manually rotate the
drive shaft (key 3) counterclockwise until the disk has
moved a full 180 degrees away from the closed posi-
tion.
2. Lay the valve flat on a work bench in a secure posi-
tion with the retaining ring (key 18) and retaining ring
screws (key 19) facing up. Properly secure the valve
on a suitable worktable so it can not slip, twist, or fall
during maintenance. Remove all retaining ring screws.
3. Remove the retaining ring by placing a socket head
retaining ring screw from the retaining ring in each of
the two retaining ring jacking screw holes. Slowly turn
the screws until the retaining ring has been lifted from
the valve body. Remove the retaining ring to expose
the seal ring in the T-slot area of the valve body.
Note
The Type A31A valve is available with
different seal designs and components.
See figure 3 to identify the specific seal
design.
4. Insert a regular screw driver or other similar tool
under the top edge of the seal ring (key 5), and gently
pry it out of the T-slot area in the valve body. Take
care not to damage the seal ring or T-slot area of the
valve body. After the seal ring has been removed,
clean the T-slot area, retaining ring, and, if required,
polish the disk thoroughly with fine steel wool or other
appropriate material.
PTFE 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.
Before installing the seal ring into the valve body,
place the backup ring (key 6) into the wide, outer
groove of the seal ring.
2. Install the seal ring and backup ring assembly in
the valve body. The wider outside diameter of the seal
ring, goes into the T-slot area of the valve body as
shown in figure 6. Start the edge with the wider diame-
ter into the T-slot of the valve body using a blunt-end
screwdriver. If a maintenance kit is available, use the
seal ring installation tools.
3. Carefully tuck the backup ring downward into the
valve body T-slot until the seal ring and backup ring
are completely entrapped in the valve body T-slot.
4. Completely seat the seal ring in the valve body T-
slot. Re-install the retaining ring (key 18) and retaining
ring screws (key 19). Tighten the screws just enough
to eliminate any movement of the retaining ring. Using
a blunt-end tool, carefully tuck the lip of the seal ring
under the retaining ring.
5. When the seal ring is under the lip of the retaining
ring, tighten the screws according to standard proce-
dures. Do not fully torque screws at this time. Final
tightening of the screws is accomplished in step 7.
6. Manually rotate the drive shaft (key 3) clockwise
180 degrees to return the disk (key 2) to its closed
position.
7. The final seating of the retaining ring cap screws
can now be done. For the screw torque values, refer
to table 6. The seal is now completely installed and the
valve may be placed in service.
