Instruction manual

Instruction Manual

D500248X012

A31D Valve

April 2014

Packing Maintenance

TheA31Dvalveisdesignedsothepackingcanbereplacedwithoutremovingthevalvefromtheprocesspipeline.

CAUTION

For non-ENVIRO-SEAL packing: Tighten the packing follower nuts only e nough to prevent shaft leakage. Excessive

tightening will accelerate wear of the packing and could produce higher friction loads on the valve stem.

Usually, packing leakage can be eliminated by m erely tightening the hex n uts (key 15) located above the packing

follower (key 12) while the valve is in the pipeline. However, if leakage continues, the packing must be replaced.

For PTFE ENVIRO-SEAL packing system, refer to instruction manual, Fisher ENVIRO-SEAL Packing System for Rotary

Valves (D101643X012) (see figure 8).

CAUTION

Never use a wrench or pliers on the drive shaft (key 3). A damaged shaft could c ut the packing and a llow leakage.

1. Before loosening any parts on the valve, release the pressure from the pipeline. Then, remove the hex nuts (key 15)

and lift off the packing follower (key 12).

2. Remove the hex jam nuts (key 17) and the anti-blowout flange (key 10). Remove the packing follower (key 12).

Refer to figure 6 for details of the anti-blowout protection parts.

The packing is now accessible.

3. Use a packing extractor to remove packing. Insert the corkscrew-like end of the tool into the first piece of packing

and pull firmly to remove the packing. Repeat this process until all packing parts have been removed.

CAUTION

Be careful when cleaning the packing box. Scratches to the drive shaft (key 3) or inside diameter of the packing bore might

cause leakage.

4. Before installing new packing, clean the packing box.

5. Install new packing one ring at a time, using the packing follower as a driver. If using split-ring packing, stagger the

splitsintheringstoavoidcreatingaleakpath.

6. Reinstall the packing parts. Refer to figure8forthesequenceofpackingparts.

Removing the Valve

1. Disconnect any operating lines providing air pressure, electric power, or a control signal to the actuator. Be sure the

actuator cannot suddenly open the valve. Vent the power actuator loading pressure.

2. Use bypass valves or completely shut off the process to isolate the valve from process pressure. Relieve process

pressure on both sides of the valve. Drain the process media from either side of the valve.