EU and EW Series Valves
Instruction Manual
August 2010
11
18.
For spring-loaded PTFE V-ring packing
,
tighten the packing flange nuts until the shoulder on
the packing follower (key 13, figure 5) contacts the
bonnet.
For graphite packing
, tighten the packing flange
nuts to the maximum recommended torque shown in
table 3. Then, loosen the packing flange nuts and
retighten them to the recommended minimum torque
shown in table 3.
For other packing types
, tighten the packing flange
nuts alternately in small, equal increments until one
of the nuts reaches the minimum recommended
torque shown in table 3. Then, tighten the remaining
flange nut until the packing flange (key 3, figure 5) is
at a 90-degree angle to the valve stem.
19. Mount the actuator on the valve assembly, and
reconnect the actuator and valve stem according to
the procedure in the appropriate actuator instruction
manual. Check for leakage around the packing
follower when the valve is being put into service.
Retighten the packing flange nuts as required.
Trim Maintenance
Trim Removal
Except where indicated, key numbers in this section
are shown in figure 8 for EUT-2 and EWT-2 valves
and in figure 7 for EUD and EWD valves.
1. Isolate the control valve from the line pressure,
release pressure from both sides of the valve body,
and drain the process media from both sides of the
valve. If using a power actuator, also shut off all
pressure lines to the power actuator, release all
pressure from the actuator, and use lock-out
procedures to prevent injury while you work on the
equipment.
2. Remove the actuator and the bonnet according to
steps 2 through 5 of the Replacing Packing Section.
CAUTION
Use care to avoid damaging gasket
surfaces.
The surface finish of the valve stem
(key 7) is critical for making a good
packing seal. The inside surface of the
cage or cage assembly (key 3) is
critical for smooth operation of the
valve plug and for making a seal with
the seal ring (key 28). The seating
surfaces of the valve plug (key 2) and
seat ring (key 9) are critical for proper
shutoff. Assume all these parts are in
good condition, and protect them
accordingly unless inspection reveals
otherwise.
3. Packing parts can be removed if desired.
Replace these parts as described in the Packing
Replacement section.
4. Lift the valve plug and stem assembly out of the
valve body and set it on a protective surface. If the
valve plug is to be reused, protect the valve plug
seating surface to prevent scratches.
5. Install screws or bolts into the tapped holes in the
top of the cage assembly (key 3), and carefully lift it
out of the valve body. Remove the gaskets (keys 10
and 11).
6. Proceed as appropriate:
For EUT-2 or EWT-2 valves (figure 7)
, the valve
has a seat ring seal ring (key 6). Inspect this seal
ring, and remove it if replacement is necessary. 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
For all sizes except the NPS 12 and 16 x 12
,
there are slots cut in the seat ring. Insert a bar
through the slots and turn the seat ring out of the
cage.
D
For the NPS 12 and 16 x 12
, 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 EUD, EWD, EUT, and EWT valves (figure 8)
,
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
