Fisher Design ED series Instruction Manual page 12

Design ED & EAD Class 125-600
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37B1045-A / DOC
An installation tool must be used to
properly position the C-seal plug seal on
the valve plug. A tool is available as a
spare part from Fisher or a tool could be
manufactured following the dimensions
given in Figure 7.
3. Place the C-seal plug seal over the top of the valve
plug and press the C-seal plug seal onto the plug
using the C-seal installation tool. Carefully press the
C-seal plug seal onto the plug until the installation tool
contacts the horizontal reference surface of the valve
plug (figure 8).
4. Apply a suitable high-temperature lubricant to the
threads on the plug. Then, place the C-seal retainer
onto the plug and tighten the retainer using an
appropriate tool such as a strap wrench.
5. Using an appropriate tool such as a center punch,
stake the threads on top of the plug in one place
(figure 9) to secure the C-seal retainer.
6. Install the new plug/retainer assembly with C-seal
plug seal on the new stem following the appropriate
instructions in the Trim Replacement section of this
manual.
7. Install piston rings by following instructions in the
Trim Replacement section of this manual.
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VIEW A
Figure 6. Design ED with C-seal Trim
Note
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37B1397-A / DOC
CAVITROL III 2 STAGE
8. 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.
9. 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.
10. Replace all gaskets according to appropriate
instructions in the Trim Replacement section of this
manual.