Lapping Metal Seats On Valves With Plain And Extension Bonnets; Assembly - Fisher EZ easy-e Instruction Manual

Instruction Manual
D100401X012
5. Remove the stem/bellows assembly from the soft‐jaw chuck or vise. Place a wrench on the flat areas on the valve
stem just below the threads for the actuator/stem connection to keep the stem from turning. Then, unscrew the
adaptor (key 24, figure 11), which also includes the valve plug (key 2) or valve plug guide (key 27, figure 13), from
the stem/bellows assembly (key 20, figure 11).
6. Remove the seat ring retainer and bushing assembly (keys 3 and 26) by sliding it over the adaptor. If the valve plug
is to be reused, protect the valve plug seating surface to prevent scratches.
7. For valves with metal seats, drive out the pin (key 8) and unscrew the adaptor (key 24, figure 11) from the valve
plug (key 2).
8. For valves with 0.25 and 0.375‐inch ports and composition seats, refer to figure 13. Drive out the pin (key 8) and
unscrew the adaptor (key 24, figure 11) from the valve plug guide (key 27). Unscrew the disk retainer (key 28) from
the valve plug guide. Remove the disk (key 29) from the valve plug tip (key 30).
For valves with 0.5 through 2‐inch ports and composition seats, refer to figure 13. Drive out the pin (key 8) and
unscrew the adaptor (key 24, figure 11) from the valve plug guide (key 27). Drive out the pin (key 31) and unscrew the
tip (key 30) from the valve plug guide. Remove the disk (key 29) from the valve plug guide.
For valves with 3 and 4‐inch ports and composition seats, refer to figure 13. Drive out the pin (key 8) and unscrew the
adaptor (key 24, figure 11) from the valve plug guide (key 27). Remove the cap screw (key 32) to remove the tip (key
30) from the valve plug guide. Remove the disk (key 29).
9. Remove the seat ring and seat ring gasket (keys 9 and 13).
10. Inspect parts for wear or damage that would prevent proper operation of the valve. Replace or repair trim parts
according to the following Assembly procedure as appropriate.

Lapping Metal Seats on Valves with Plain and Extension Bonnets

CAUTION
To avoid damaging the ENVIRO‐SEAL Bellows Seal Bonnet assembly, do not attempt to lap the metal seating surfaces on
valves with ENVIRO‐SEAL bellows seal bonnets. The design of the bonnet assembly prevents rotation of the stem and any
forced lapping rotation will damage internal components of the ENVIRO‐SEAL Bellows Seal bonnet.
With metal‐seat constructions, seating surfaces of the valve plug and seat ring (key 2, figure 12) can be lapped for
improved shutoff. (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 seat ring retainer is 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.
Note
EZ valves with Overtravel (EZ-OVT) trim should not be lapped.

Assembly

This procedure assumes that all the trim and associated gaskets were removed from the valve body. If these parts were
not all removed, start the assembly procedure at the appropriate step. Except where indicated, key numbers
referenced in the following steps are found in figure 12.
EZ Valve
November 2017
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