Replacing Retainer, Seat Ring, And Face Seals; Disassembly - Fisher CV500 Instruction Manual

CV500 Valve
June 2017
4. Remove the old packing rings (key 13), packing box ring (key 17), and, if used, the lantern ring (key 18). Do not
scratch the valve shaft or packing box wall; scratching these surfaces could cause leakage. Clean all accessible metal
parts and surfaces to remove particles that would prevent the packing from sealing.
5. Whenever you are installing new packing, be sure the ball (key 2) is closed while you install and tighten the new
packing. Install the new packing rings and packing box ring by stacking the parts as shown in figure 4. Make sure
split rings are arranged so that the splits do not line up to form a leak path. Then slide the stack into the packing box
as far as they will go while being careful to avoid trapping air among the rings.
6. Install the packing follower (key 14), and, for NPS 10 and 12, also install the packing flange (key 45). Install the nuts
(key 16), and tighten them far enough to stop leakage under normal conditions.
7. Mount the actuator while referring to the actuator mounting procedures in the actuator instruction manual.
Complete the Adjusting Actuator Travel procedure in this manual before installing the valve in the pipeline. This is
necessary due to the measurements that must be made during the actuator adjustment process.
8. When the control valve is being put back into operation, check the packing follower for leakage, and retighten the
packing nuts as necessary.

Replacing Retainer, Seat Ring, and Face Seals

This procedure is to be performed if the control valve is not shutting off properly, if installing a different seat ring, or if
seat ring inspection is necessary. The actuator and valve must be removed from the pipeline; however, the actuator
may remain mounted during this procedure. Key numbers refer to figure 9 for NPS 3 through 8 and to figure 10 for
NPS 10 and 12 unless otherwise indicated.
A retainer tool is required to remove the retainer (key 5). If specifically ordered, a tool is supplied with the valve; a tool
can also be ordered individually by referencing key 33 of the Parts List. If desired, a tool can be machined using the
dimensions shown in figure 5.
CAUTION
During assembly, handle the retainer, seat ring, and face seals carefully. Critical areas that must be protected are the
threads and inner surface of the retainer (key 5), the sealing surfaces of the face seals (key 8), the face seal grooves in the
seat ring (key 4), the shutoff surface of the seat ring, and the face seal surface in the valve body.
A new retainer gasket (key 11) is required whenever the retainer (key 5) is removed. Other parts that are in good
condition can be reused.

Disassembly

WARNING
Refer to the WARNING at the beginning of the Maintenance section in this instruction manual.
Table 4. Assembly Clearance
PROCESS
TEMPERATURE
To 260_C
(1)
(500_F)
Over 260_C
(2)
(500_F)
1. Standard Trim
2. Special High Temperature Trim
10
mm
Minimum
0.08
0.20
SEAT RING AND RETAINER CLEARANCE
Maximum
0.30
0.43
Instruction Manual
Inches
Minimum
0.003
0.008
D101640X012
Maximum
0.012
0.017