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Instruction Manual
D103553X012
For ET valves with HTS1 option (figure 7), the valve has a seat ring seal ring (figure 5, 6, or 7, key 6). Inspect this seal
ring, and remove it if replacement is necessary. To remove the seal ring, the retaining ring (key 227) must be removed
first. After the retaining ring is removed, the seal ring (key 6), backup ring (key 226), and anti-extrusion rings (key 225)
can be removed. The seat ring is screwed into the cage and secured with two tack welds, one on each side of the cage.
Remove the tack welds by grinding or filing them off.
D There are two 3/8-inch UNC tapped holes in the bottom of the seat ring. Screw cap screws into these holes. Use a
bar to pry against the cap screws and turn the seat ring out of the cage.
For ED valves (figure 6), unscrew the seat ring cap screws (key 49). Install screws or bolts into the tapped holes in the
top of the seat ring (key 9) and carefully lift it out of the valve body. Remove the gasket (key 13).
7. Inspect parts for wear or damage that would prevent proper operation of the valve. Replace or repair trim parts
according to the following Lapping Seating Surfaces or Valve Plug Maintenance procedures as appropriate.
Lapping Seating Surfaces
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 or cage assembly 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 the valve as described in the Trim Replacement 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 shown in figure 6 for ET valves and in figure 5 for ED valves.
CAUTION
For valves with a PTFE seal ring (figure 5, 6, or 7), if replacing the valve plug 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. Remove the valve plug (key 2) according to the Disassembly section.
2. For ET constructions, carefully pry or cut the seal ring (key 28, figure 5, 6, or 7) from its groove in the plug.
Install the replacement spring-loaded seal ring with the open side facing the top or bottom of the valve plug,
depending on flow direction. The open side of the seal ring should face up (toward the actuator) in flow-up
installations and down in flow-down installations.
To install the seal ring, first lubricate it with general-purpose, lithium-base lubricant. Then gently stretch the seal ring
and work it over the top edge of the valve plug. Give the PTFE material in the seal ring time to cold flow during the
stretching procedure. Avoid jerking sharply on the ring. Stretching the seal ring over the valve plug might make it
seem loose when it is in the groove, but it will shrink to its original size after you have installed the plug into the cage.
3. For ET valves with HTS1 option (figure 5, 6, or 7), carefully pry the retaining ring from the groove in the plug. Then
remove the seal ring (key 28), backup ring (key 29), and anti-extrusion ring (key 219). Install the seal ring and other
parts according to figure 5, 6, or 7. The open side faces the valve stem for Whisper Trim III, WhisperFlo, and flow-up
standard cages. Reverse the seal ring for flow-down cages.
Large ET and ED Valves
July 2014
13
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