Instruction manual

Instruction Manual
D500240X012
A31A Valve
October 2012
14
2. Use bypass valves or completely shut off the process to isolatethevalvefromprocesspressure. Relieve process
pressure on both sides of the valve. Drain the process media from either side of the valve.
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 loosening 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 replace the seal ring (key 5) while the actuator is mounted to the valve and can be accomplished
by cycling the valve to 90 degrees open.
1. Afterremovingthevalvefromthepipeline,removethemanualorpoweractuator.Manuallyrotatethedriveshaft
(key 3) counterclockwise until the disk has moved a full 180 degrees away from the closed position.
2. Lay the valve flat on a work bench in a secure position 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.RemovetheretainingringtoexposethesealringintheT-slotareaofthevalvebody.
Note
The 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 t he 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 Emerson Process Management sales office.