Lapping Metal Seats; Valve Plug Maintenance; Assembly - Fisher EAS easy-e Instruction Manual

Instruction Manual
D100397X012

Lapping Metal Seats

A certain amount of leakage should be expected with metal‐to‐metal seating in any valve body. If the leakage
becomes excessive, however, the condition of the seating surfaces of the valve plug and seat ring can be improved by
lapping. (Deep nicks should be machined out rather than ground out.) Use a good quality lapping compound of a
mixture of 280 to 600‐grit. Apply the compound to the bottom of the valve plug.
Assemble the valve to the extent that the cage and the cage retainer and bonnet spacer (if used) are in place and the
bonnet is bolted to the valve body. A simple handle can be made from a piece of strap iron locked to the valve plug
stem with nuts. Rotate the handle alternately in each direction to lap the seats. After lapping, remove the bonnet and
clean the seat surfaces. Completely assemble as described in the assembly portion of the trim maintenance procedure
and test the valve for shutoff. Repeat the lapping procedure if leakage is still excessive.
CAUTION
To avoid weakening the stem or adaptor that may cause failure in service, never reuse an old stem or adaptor with a new
valve plug. Using an old stem or adaptor with a new plug requires drilling a new pin hole in the stem (or adaptor in case an
ENVIRO‐SEAL bellows seal bonnet is being used), which will weaken the stem. However, a used valve plug may be reused
with a new stem or adaptor.

Valve Plug Maintenance

Except where indicated, key numbers are referenced in figure 13 for NPS 1/2 through 6 constructions, figure 14 for
NPS 8 ES valves, figure 15 for Whisper Trim III cage detail, and figure 16 for WhisperFlo trim.
1. Remove the valve plug (key 2) according to the disassembly portion of the trim maintenance procedure.
2. To replace the valve stem (key 7), drive out the pin (key 8). Unscrew the valve plug from the stem or adaptor.
3. To replace the adaptor (key 24, figure 8) on ENVIRO‐SEAL bellows seal bonnets, place the plug stem 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 36, figure 8). Reverse the plug stem 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 valve plug/adaptor assembly (key 24, figure 8) from the valve stem assembly (key 20, figure 8).
4. Screw the stem or adaptor into the valve plug. Tighten to the torque value given in table 5. Refer to table 5 to select
the proper hole size. Drill through the stem or adaptor, using the hole in the valve plug as a guide. Remove any
chips or burrs and drive in a new pin to lock the assembly.
5. For ENVIRO‐SEAL bellows seal bonnets, grip the flats of the stem extending out of the top of the bellows shroud
with a soft‐jaw chuck or other type of vise. Screw the valve plug/adaptor assembly onto the valve stem. Tighten as
necessary to align the pin hole in the stem with one of the holes in the adaptor. Secure the adaptor to the stem with
a new pin.

Assembly

Except where indicated, key numbers are referenced in figure 13 for standard NPS 1/2 through 6 constructions, figure
14 for NPS 8 ES valves, figure 15 for Whisper Trim III cage detail, and figure 16 for WhisperFlo trim.
1. With a restricted trim seat ring construction, install the adaptor gasket (key 14) and seat ring adaptor (key 5).
2. Install the seat ring gasket (key 13), seat ring or liner (key 9), or disk seat (key 22). With a PTFE seat construction,
install the disk and disk retainer (keys 21 and 23).
3. Install the cage or cage/baffle assembly (key 3). Any rotational orientation of the cage or assembly with respect to
the valve is acceptable. A Whisper Trim III cage designated by level A3, B3, or C3 may be installed with either end
ES Valve
July 2017
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