Instruction manual

Instruction Manual
D500240X012
A31A Valve
October 2012
12
D Use bypass valves or completely shut off the process to isolate the valve from process pressure. R elieve process pressure
on both sides of the valve. Drain the process media from either side of the valve.
D Vent the power actuator loading pressure and relieve any actuator spring precompression.
D Use lock-out procedures to be sure that the above measures stay in effect while you work on the equipment.
Replacing Packing
The A31A valve is designed so the packing can be replaced without removing the valve from the process pipeline.
Packing may be PTFE V-rings or graphite.
If you are installing an ENVIRO-SEAL™ Packing System in an existing valve, follow the instructions in the ENVIRO-SEAL
Rotary Packing Instruction Manual (D101643X012). To remo ve packing parts in a valve with the ENVIRO-SEAL packing
system, follow the procedures for valves using ENVIRO-SEAL packing system in this section.
Figure 5. Properly Installed Wafer Style Valve
A5557
For valves with PTFE or graphite packing:
Key numbers for the parts in this section may be found in figure 7.
CAUTION
Tighten the packing flange only enough to prevent shaft leakage. Excessive tightening will only accelerate wear of the
packing and could produce higher torques on the valve.
Usually, packing leakage can be eliminated by merely tightening the hex nuts (key 15) located above the packing
flange while the valve is in t he pipeline. However, if leakage continues, replace the packing.
CAUTION
Never use a wrench or pliers on the valve shaft. A damaged shaft could cut the packing and allow leakage.