Fisher GX 3-Way, Инструкция по эксплуатации, Страница: 16 / 28

Instruction Manual
D103312X012
GX 3-Way Valve and Actuator
July 2017
16
CAUTION
Use care to avoid damaging the gasket sealing surfaces.
The surface finish of the valve stem (key 3) is critical for making a good packing seal. The seating surfaces of the seat ring or
cage (key 2) and the valve plug (key 3) are critical for tight shutoff and should therefore also be treated with care and
properly protected.
1. Packing parts can be removed from the bonnet if desired. Replace these parts as described in the section on Packing
Maintenance .
2. Use a seat ring or cage tool made according to the dimensions in figure 6 and table 6 to remove the seat ring or
cage (key 2) as follows:
a. Insert the tool into the valve body. Be certain the tool lugs are engaged in the corresponding recesses in the seat
ring or cage.
b. Use care to avoid damaging or scratching the bonnet and cage guide surfaces (see figures 9 and 10).
c. Use a torque gun or driver having sufficient torque capabilities according to table 7. Connect the gun to a socket
that snugly fits the hex head on the seat ring or cage tool.
d. Insert the socket onto the hex head of the seat ring or cage tool.
WARNING
Be careful to hold the torque gun, attached socket, and tool at right angles to the seat ring or cage when applying torque.
Tilting the gun and socket while applying torque may cause the lugs on the seat ring or cage tool to suddenly disengage
from the lugs on the seat ring or cage thus causing possible damage to the seat ring or cage and possible personal injury.
3. Remove the seat ring or cage (key 2) from the valve body.
4. Inspect parts for wear or damage that would prevent proper operation of the valve.
Side‐Port Common Trim Assembly
Refer to figure 9.
1. Before installing the new seat ring, thoroughly clean the threads in the valve body. Apply suitable lubricant to the
threads and to the radius surface of the seat ring (key 2). Screw the seat ring into the valve body. Using the seat ring
tool, tighten the seat ring and torque according to the values in table 7. Remove all excess lubricant after
tightening.
2. Clean the body/yoke gasket surfaces and install a new body/yoke gasket (key 5).
3. Remove any protective tape or covering from the valve plug/stem assembly.
4. Insert the plug/stem assembly into the seat ring.
5. Install a new bonnet O‐ring (key 81) in the groove on the bonnet (see figure 9). Apply a general purpose
silicone‐based lubricant.
D
For HT constructions, see figure 12. Install a new graphite seal ring (key 107) in the groove on the bonnet. Apply
a general purpose silicone lubricant.
CAUTION
If the packing is to be reused and was not removed from the bonnet, perform the following step carefully to avoid
damaging the packing with the stem threads.