Instruction Manual
D100399X012
EW Valve
July 2017
16
Figure 7. TSO (Tight Shutoff Trim), Detail of Protected Soft Seat
INNER PLUG
OUTER PLUG
CAGE
SEAT RING
PROTECTED SOFT SEAT
A7088
7.
For constructions other than TSO (tight shutoff trim)
, remove the seat ring (key 9) or disk seat (key 22), seat ring
gasket (key 13), and the seat ring adaptor (key 5) and adaptor gasket (key 14) where used in a restricted‐capacity
construction. EWS and EWT PTFE‐seat constructions use a disk (key 23) sandwiched between the disk seat and disk
retainer (key 21). A CL900 NPS 8x6 EWT construction with Cavitrol III cage has its spiral wound gasket (key 12) on
the side of the seat ring opposite the seat ring gasket.
8.
For TSO (tight shutoff trim) constructions
, perform the following steps (refer to figures 7 and 8):
D
Remove the piston ring, anti‐extrusion rings, backup ring, and retainer.
D
Remove the set screws that lock the outer plug to the inner plug.
D
Using a strap wrench or similar tool, unscrew the outer plug from the inner plug. Do not damage the outer plug
guide surfaces.
D
Remove the protected soft seat seal.
D
Inspect the parts for damage and replace if needed.
9.
For all constructions
, inspect parts for wear or damage that would prevent proper operation of the valve. Replace or
repair trim parts according to the following procedures for lapping metal seats or other valve plug maintenance
procedures, as appropriate.
Lapping Metal Seats
CAUTION
To avoid damaging the ENVIRO‐SEAL bellows seal bonnet assembly, do not attempt to lap the metal seating surfaces. The
design of the assembly prevents rotation of the stem and any forced rotation will damage internal components of the
ENVIRO‐SEAL bellows seal bonnet.