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

5. Then, reverse the plug stem assembly in the
soft-jaw chuck or vise. Grip the valve stem in an
appropriate place and unscrew the existing plug from
the valve stem.
CAUTION
When 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.
6. To attach the valve plug to the stem of the new
ENVIRO-SEAL stem/bellows assembly, it is necessary
to first attach the plug to the adaptor (key 24). Locate
the adaptor. Notice that a hole has not been drilled in
the threads where the plug screws onto the adaptor.
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. Thread the adaptor into the
valve plug and tighten to the appropriate torque value.
7. Select the proper size of drill bit and drill through
the adaptor using the hole in the valve plug as a guide.
Remove any metal chips or burrs and drive in a new
pin (key 8, figures 19, 20, and 21) to lock the
plug/adaptor assembly together.
8. Attach the plug/adaptor assembly to the
ENVIRO-SEAL stem/bellows assembly by first
securing the stem/bellows assembly in a soft-jaw
chuck or other type of vise so that the jaws of the
chuck or vise grip the flats of the stem extending out of
the top of the bellows shroud. Screw the valve
plug/adaptor assembly onto the valve stem. Tighten
the plug/adaptor assembly until it is snug. Then turn
the plug/adaptor assembly to the next pin hole in the
valve stem. Drive in new pin (key 36, figure 18) to lock
the assembly.
9. Inspect the seat ring (key 9). Replace, if necessary.
10. Place a new gasket (key 10) into the valve body in
place of the bonnet gasket. Install the new
stem/bellows assembly with valve plug/adaptor by
placing it into the valve body on top of the new bellows
gasket.
Design ED & EAD Class 125-600
Note
Table 6. Recommended Torque for ENVIRO-SEAL
Bellows Seal Bonnet Packing Flange Nuts
VALVE
MINIMUM TORQUE
VALVE STEM
SIZE, SIZE,
DIAMETER DIAMETER
INCHES THROUGH
NSm
PACKING
1/2 - 2 1/2 2
3 - 8 1 5
11. Place a new gasket (key 22) over the
stem/bellows assembly. Place the new ENVIRO-SEAL
bonnet over the stem/bellows assembly.
12. Properly lubricate the bonnet stud bolts. Install
and tighten the bonnet hex nuts to the proper torque.
13. Install the new packing and the metal packing box
parts according to the appropriate arrangement in
figure 12 or 13.
14. Install the packing flange. Properly lubricate the
packing flange stud bolts and the faces of the packing
flange nuts.
For graphite packing, tighten the packing flange
nuts to the maximum recommended torque shown in
table 6. Then, loosen the packing flange nuts, and
retighten them to the recommended minimum torque
shown in table 6.
For other packing types, tighten the packing flange
nuts alternately in small equal increments until one of
the nuts reaches the minimum recommended 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 the 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
of the Maintenance section.
2. 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.
MAXIMUM
TORQUE
LbfSin NSm LbfSin
22 4 33
44 8 67
17