Instruction Manual
D100399X012
EW Valve
July 2017
17
Figure 8. Typical Balanced TSO Trim
VALVE PLUG
SEAL
PROTECTED
SOFT SEAT
A7096
Except with respect to the ENVIRO‐SEAL Bellows Seal Bonnet assembly, with metal seat constructions, seating surfaces
of the valve plug and seat ring (keys 2 and 9, figures 24 through 26) 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 cage (and cage retainer and bonnet spacer, if used) is in place and the
bonnet is bolted to the valve. 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 the valve as described in the Trim Replacement portion of the Trim
Maintenance section, and test the valve for shutoff. Repeat the lapping procedure if leakage is still excessive.
Valve Plug Maintenance
Except where indicated, key numbers in this section are referenced in figure 22 for EWD valve plugs, figure 23 for EWS
valve plugs, and figure 24 for EWT valve plugs.
CAUTION
If replacing the piston ring (key 6) or seal ring (key 28), be careful not to scratch the surfaces of the ring groove in the valve
plug or any of the surfaces of the replacement ring, or the replacement ring may not seal properly.
1. With the valve plug (key 2) removed, according to the Trim Removal section, proceed as appropriate:
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