Instruction manual

Instruction Manual

D500240X012

A31A Valve

October 2012

1. Before loosening any parts, isolate the valve from the line pressure, release pressure from both sides of the valve

body, and drain the process media from both sides of the valve. Then, remove the hex nuts (key 15) and lift off the

packing flange (key 11).

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

anti-blowout ring (key 16) using a needle-nose pliers. The packing (key 13) is now accessible. Refer to figure 6 for

details of t he blowout protection.

3. Use a packing extractor to remove packing. Insert the corkscrew-likeendofthetoolintothefirstpieceofpacking

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

CAUTION

Be careful when cleaning the packing box. Scratches to the shaft or inside diameter of packing bore might cause leakage.

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

5. Install new packing (key 13) one ring at a time, using the packing follower (key 12) as a driver. If u sing split-ring

packing, stagger the splits in the rings to avoid creating a leak path.

6. Reinstall all parts. Tighten the packing flange nuts (key 15) as needed to stop leakage under operating conditions.

For valves using the ENVIRO-SEAL packing system:

Normally, the packing nuts should not require re-tightening. However, when servicing an ENVIRO-SEAL packing

system, i f the springs do not remain nearly flat, retighten the packing box nuts until the springs are almost completely

compressed. If leakage continues, replace the packing components as described in the following procedures. Keys

numbers in this section may be found in figure 7.

CAUTION

Be careful when cleaning the packing box. Scratches to the shaft or inside diameter of the packing bore may cause leakage.

1. Before loosening any parts on the valve, isolate the control valve from the line pressure and release pressure from

both sides of the valve body.

2. Loosen the two packing hex nuts evenly to remove spring tension, then remove the nuts.

3. Remove the packing flange and spring stack. The spring stack is held in place by an O-ring on the packing flange.

Remove the two hex jam nuts and remove the anti-blowout flange, packing flange, anti-blowout ring, packing box

ring, anti-extrusion washer, packing set, and packing box ring.

CAUTION

The valve shaft surface condition is critical in making and maintaining a good seal. If the valve shaft surface is scratched,

nicked, dented, or worn, replace the valve shaft before replacing the packing system components.

4. Inspect the existing valve shaft. If necessary, replace the valve shaft as described in the procedures in this section.

5. Install the new packing system components as described in the ENVIRO-SEAL Rotary Packing Instruction Manual

(D101643X012).

Removing the Valve from the Pipeline

1. Disconnect any operating lines providing air pressure, electricpower,oracontrolsignaltotheactuator.Besurethe

actuator cannot suddenly open the valve. Ventthepoweractuatorloadingpressure.