Trim Removal - Fisher EWS Series Instruction Manual

EW Valve
figure 24 for Design EWT constructions. Refer to
figures 26 and 27 for Cavitrol III, figure 27 for
Whisper Trim III, and figure 29 for WhisperFlo
construction.

Trim Removal

1. Remove the actuator and the bonnet according to
steps 1 through 5 of the Replacing Packing
procedure.
WARNING
Avoid personal injury or property
damage from valve or packing leakage.
When lifting the valve plug stem (key
7) and attached valve plug (key 2) out
of the valve, be certain that the cage
(key 3) remains in the valve (key 1).
This will prevent cage damage that
might be caused by the cage dropping
back into the valve after being lifted
part way out.
Use care to avoid damaging gasket
sealing surfaces.
Each graphite piston ring (key 6) in a
Design EWD valve is brittle and in two
pieces. Use care to avoid damage to
the piston ring(s) caused by dropping
or rough handling.
Any damage to the gasket sealing
surfaces could cause the valve to leak.
12
INNER PLUG
PROTECTED SOFT SEAT
SEAT RING
A7088 / IL
Figure 7. TSO (Tight Shutoff Trim), Detail of Protected Soft Seat
OUTER PLUG
The surface finish of the valve stem
(key 7) is critical for making a good
packing seal. The inside surface of the
cage or cage/baffle assembly (key 3) or
cage retainer (key 31) is critical for
smooth operation of the valve plug
and for making a seal with the piston
ring (key 6) or seal ring (key 28). The
seating surfaces of the valve plug (key
2) and the seat ring (key 9) on a
metal-seat construction are critical for
tight shutoff. Protect these parts
accordingly while disassembling the
trim.
2. Remove the packing flange nuts, packing flange,
upper wiper, and packing follower (keys 5, 3, 24,
and 25, figure 21). Carefully push out all the
remaining packing parts from the valve side of the
bonnet using a rounded rod or other tool that will not
scratch the packing box wall. Clean the packing box
and the metal packing parts.
3. Inspect the valve stem threads and packing box
surfaces for any sharp edges which might cut the
packing. Scratches or burrs could cause packing box
leakage or damage to the new packing. If the
surface condition cannot be improved by light
sanding, replace the damaged parts.
4. Remove the load ring (key 26) from an NPS 10x8
or 12x8 valve or the cage adaptor (key 4) from any
restricted-trim valve through NPS 8x4, and wrap it
for protection.
5. On a 102 mm (4-inch) travel valve with Whisper
Trim I cage or on any NPS 8x6 or 12x6 valve with
Instruction Manual
Form 2376
March 2007
CAGE