Replacement Of Installed Bore Seal Trim; Trim Removal (Bore Seal Constructions) - Fisher EUT-2 Instruction Manual

Instruction Manual
August 2010
10. Remove the existing valve actuator and bonnet
following the appropriate instructions in the
Replacing Packing section of this manual.
CAUTION
Do not remove the existing valve stem
from the valve plug 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
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.
11. Remove the existing valve stem and plug, cage,
and seat ring from the valve body following the
appropriate instructions in the Trim Removal section
of this manual.
12. Replace all gaskets according to appropriate
instructions in the Trim Replacement section of this
manual.
13. Install the new seat ring, cage, valve
plug/retainer assembly, and stem into the valve body
and completely reassemble the valve package
following the appropriate instructions in the Trim
Replacement section of this manual.
CAUTION
To avoid excessive leakage and seat
erosion, the valve plug must be
initially seated with sufficient force to
overcome the resistance of the Bore
Seal and contact the seat ring. You can
correctly seat the valve plug by using
the same force calculated for full load
when sizing your actuator. With no
pressure drop across the valve, this
force will adequately drive the valve
plug to the seat ring, thus giving the
Bore Seal a predetermined permanent
set.
With full actuator force applied and the
valve plug fully seated, align the
actuator travel indicator scale with the
lower end of valve travel. Refer to the
appropriate actuator instruction
EU and EW Series Valves
manual for information on this
procedure.
Replacement of Installed Bore Seal
Trim

Trim Removal (Bore 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 the Bore 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
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 Bore
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 12). 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 from the groove in the Bore Seal retainer.
5. After removing the piston ring, locate
the 1/4-inch diameter hole in the groove.
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