Replacement Of Installed C-Seal Trim; Trim Removal (C-Seal Constructions) - Fisher Design ED series Instruction Manual

Design ED & EAD Class 125-600
INSTALLATION
TOOL
C SEAL
METAL
PLUG
SEAL
FLOW DOWN
NOTE:
PRESS INSTALLATION TOOL OVER VALVE PLUG
UNTIL THE TOOL CONTACTS THE HORIZONTAL REFERENCE SUR-
FACE OF THE VALVE PLUG.
A6778 / IL
Figure 8. Installing the C-seal Plug Seal Using the
Installation Tool

Replacement of Installed C-seal Trim

Trim Removal (C-seal Constructions)

1. Remove the valve actuator and bonnet following
the appropriate instructions in the Replacing Packing
section of this manual.
CAUTION
To avoid leakage when the valve is
returned to service, use appropriate
methods and materials to protect all
sealing surfaces of the trim parts during
maintenance.
Use caution when removing piston
ring(s) and C-seal plug seal to avoid
scratching any sealing surface.
CAUTION
Do not remove the valve stem from the
plug/retainer assembly unless you are
planning to replace the valve stem.
Never reuse an old valve stem with a
new plug or reinstall a valve stem after it
has been removed. Replacing a valve
14
VALVE
PLUG
HORIZONTAL
REFERENCE
SURFACE
DEFORM THREAD TO
STAKE C SEAL RETAINER
PISTON
RING
RETAINER
C SEAL
METAL
PLUG
SEAL
FLOW DOWN
A6779 / IL
Figure 9. Stake the Threads of the C-seal Retainer
stem requires drilling a new pin hole in
the stem. This drilling weakens the stem
and may cause failure in service.
However, a used valve plug may be
reused with a new valve stem.
2. Remove the plug/retainer assembly (with C-seal
plug seal), cage, and seat ring from the valve body
following the appropriate instructions in the Trim
Removal section of this manual.
3. Locate the staked thread on top of the valve plug
(figure 9). The staked thread secures the retainer. Use
a drill with a 1/8-inch bit to drill out the staked area of
the thread. Drill approximately 1/8-inch into the metal
to remove the staking.
4. Locate the break between sections of the piston
ring(s). Using an appropriate tool such as a flat-blade
screwdriver, carefully pry out the piston ring(s) from
the groove(s) in the C-seal retainer.
5. After removing the piston ring(s), locate the
0.25-inch diameter hole in the groove. In a retainer
with two piston ring grooves, the hole will be found in
the upper groove.
6. Select an appropriate tool such as a punch and
place the tip of the tool into the hole with the body of
the tool held tangent to the outside diameter of the
retainer. Strike the tool with a hammer to rotate the
retainer and free it from the valve plug. Remove the
retainer from the plug.
VALVE
PLUG