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7
INSTALLATION OF NEW SEAT
1. Confirm seat is correct size and elastomer
for application.
2. Examine seat for cuts, tears and other
imperfections, do not use if seat is visibly
damaged. Apply a thin coating of Dow
Corning 111 or other similar, silicone-based
lubricant (do not use carbon-based grease)
to outside and inside edges of seat. This will
facilitate seat entry into valve body and gate
entry into seat. Soapy water may be used if
silicone-based lube is unavailable.
3. Insert seat through the valve packing box,
radiused end first, pushing it straight down
into valve throat (Figure 11).
4. Using a flat faced, round bar (no sharp
edges) and a hammer, tap packing support
bar all around the perimetre, driving the
seat until it bottoms-out in the packing box.
Take care to avoid cutting elastomer surface
of packing support bar. Seat should be
firmly seated inseat channel at this time.
5. Insert gate into packing box, radiused end
first, pushing it straight down through the
packing support bar and into valve throat as
far as possible by hand (Figure 12).
6. Repack valve, see Page 5 for instructions,
do not fully tighten.
7. Reassemble actuator assembly, aligning top
plate with four-post yoke and aligning gate
bolt holes with valve lifter, lower assembly
until top plate is in position, assemble with
hex nuts.
8. Reassemble gate to actuator assembly
using hex nuts.
9. Open valve to full open position.
10. Close valve to fully closed position.
11. Apply pressure to pipeline,
Description
Sizes DN (NPS)
Material
Seat puller
assembly
50 - 200
(2 - 8)
Carbon steel
Seat puller
assembly
50 - 200
(2 - 8)
304 S/S
Seat puller
assembly
250 - 750
(10 - 30)
Carbon steel
Seat puller
assembly
250 - 750
(10 - 30)
304 S/S
CAUTION
Packing may leak, adjust as necessary to obtain
seal.
FIGURE 11
FIGURE 12
KEYSTONE
FIGURE PCS17 KNIFE GATE VALVES
INSTRUCTION, OPERATION AND MAINTENANCE MANUAL