Trim Replacement (Bore Seal Constructions) - Fisher NPS 12 Instruction Manual

Instruction Manual
D103553X012
Figure 11. Lower (Valve Plug to Seat Ring) and Upper (Bore Seal to Cage) Seating Surfaces
RETAINER
PLUG
UPPER SEATING SURFACE
PLUG
LOWER SEATING SURFACE
NOTE:
1
UPPER SEATING SURFACE IS THE AREA OF CONTACT BETWEEN
THE BORE SEAL METAL PLUG SEAL AND THE CAGE.
A6780

Trim Replacement (Bore Seal Constructions)

1. Apply a suitable high-temperature lubricant to the inside diameter of the Bore Seal plug seal. Also, lubricate the
outside diameter of the valve plug where the Bore Seal plug seal must be pressed into the proper sealing position
(figure 8).
2. Orient the Bore Seal plug seal for correct sealing action based on the process fluid flow direction through the valve.
D The open interior of the Bore Seal plug seal must face up in a valve with flow-up construction (figure 8).
D The open interior of the Bore Seal plug seal must face down in a valve with flow-down construction (figure 8).
3. Place the Bore Seal plug seal over the top of the valve plug. The retainer will help guide the Bore Seal down onto the
plug. Do not force the Bore Seal over the plug. For flow down constructions, skip to step 5.
4. An installation tool (see table 5) must be inserted into the Bore Seal prior to using the retainer to guide it down the
plug.
5. Apply a suitable high-temperature lubricant to the threads on the plug. Then, place the Bore Seal retainer onto the
plug and tighten the retainer using an appropriate tool such as a strap wrench. For flow down constructions, skip to
step 7.
6. Remove the retainer and then the installation tool. Place the Bore Seal retainer back onto the plug and tighten the
retainer using an appropriate tool such as a strap wrench.
PISTON
RING
CAGE
SEATING AREA
BORE SEAL
CAGE
SEAT
RING
1
Large ET and ED Valves
July 2014
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