Replacement Of An Installed Enviro-Seal Bellows Seal Bonnet (Stem/Bellows Assembly) - Fisher ET Instruction Manual

Instruction Manual
Form 5081
June 2002
torque shown in table 6. Then, tighten the remaining
flange nut until the packing flange is level and at a
90-degree angle to the valve stem.
15. Install travel indicator parts and stem locknuts;
mount the actuator on the valve body according to
the procedure in the appropriate actuator instruction
manual.
Replacement of an Installed
ENVIRO-SEAL Bellows Seal Bonnet
(Stem/Bellows Assembly)
1. Remove the actuator and bonnet according to
steps 1 through 5 of the Replacing Packing
procedure in the Maintenance section.
2. Carefully remove the ENVIRO-SEAL
stem/bellows assembly. If necessary, also lift out the
cage. Remove and discard the existing bonnet
gasket and bellows gasket. Cover the valve body
opening to protect sealing surfaces and to prevent
foreign material from entering the valve body cavity.
The ENVIRO-SEAL stem/bellows
assembly for Design E valves is
available only with a threaded and
drilled plug/adaptor/stem connection.
The existing valve plug can be reused
with the new stem/bellows assembly
or a new plug can be installed. If the
existing valve plug is reused, and the
adaptor is in good condition, it may be
also reused. However, never reuse an
old adaptor with a new valve plug.
Using an old adaptor with a new valve
plug requires drilling a new pin hole in
the adaptor. This drilling weakens the
adaptor and may cause failure in
service. However, a used valve plug
may be reused with a new adaptor.
3. Inspect the existing valve plug and adaptor. If
they are in good condition, they can be reused with
the new stem/bellows assembly and they do not
need to be separated.
Note
CAUTION
When removing/installing a valve plug
on the ENVIRO-SEAL stem/bellows
assembly, the valve stem must not be
rotated. Damage to the bellows may
result.
Do not grip the bellows shroud or
other parts of the stem/bellows
assembly. Grip only the flat areas on
the stem where it extends out of the
top of the bellows shroud.
The ENVIRO-SEAL stem/bellows
assembly has a one-piece stem.
4. If the valve plug and adaptor are not in good
condition and must be replaced, first remove the
valve plug/adaptor assembly from the stem/bellows
assembly; then remove the valve plug from the
adaptor. First, place the stem/bellows assembly and
valve plug in a soft-jaw chuck or other type of vise so
that the jaws grip a portion of the valve plug that is
not a seating surface. Drive out or drill out the pin
(key 8, figure 16, 17, or 20). Drive out the pin (key 36,
figure 14).
5. Reverse the stem/bellows and plug/adaptor
assembly in the soft-jaw chuck or vise. Grip the flat
areas on the valve stem just below the threads for
the actuator/stem connection. Unscrew the
plug/adaptor assembly from the stem/bellows
assembly. Unscrew the valve plug from the adaptor.
6. To attach either the existing valve plug or a new
one to the stem of the new ENVIRO-SEAL
stem/bellows assembly, first attach the plug to the
adaptor (if the valve plug was removed from the
adaptor) as follows:
D Locate the adaptor. Notice that a hole has not
been drilled in the threads where the plug screws
onto the adaptor.
D Secure the valve plug in a soft-jaw chuck or
other type of vise. Do not grip the plug on any
seating surface. Position the plug in the chuck or
vise for easy threading of the adaptor.
D Thread the adaptor into the valve plug and
tighten to the appropriate torque value.
ET Valve
Note
15