Val-Matic 30 and Larger Butterfly Valve - Manual (Page 12)

11
REASSEMBLY (Cont’d)
3. Install new seat (6), retaining ring (7) and seat
bolts (8) into disc. Apply thin film of FDA silicone
grease such as Dow Corning #7 to rubber surface.
Lightly tighten seat bolts until bolt heads touch
ring.
4. Install thrust cap (15) and, thrust plate (18) with
the appropriate gaskets and bolts. Turn the thrust
bearing stud (17) until the disc is centered in the
valve body seat. Install lock cap (21).
5. Lubricate ID and OD of packing set with FDA
grease and install in packing bore one ring at a
time taking care to keep lips pointing down toward
valve.
6. Torque seat bolts to torque given in Table 3.
7. Insert key (24) into shaft and place actuator over
valve. Reinstall actuator mounting bolts and
torque per Table 5. Install cover on actuator.
Cycle valve. Apply pressure to valve and check
for seat leakage. Tighten seat bolts ½ turn at a
time as necessary.
8. If valve does not shut off tight, adjust the closed
position stops.
SEAT REPLACEMENT
If the seat is badly worn or damaged, gain access to
valve interior and remove existing cap screws, seat
retaining ring, and seat.
1. Clean mating surfaces of body seat, disc and
retaining ring with stiff wire brush in the direction of
the machine grooves.
2. Install new seat (6) onto disc so that the o-ring
bead side is against the disc with the holes
aligned.
3. Start at the top of the disc and install a section of
retaining ring (7) with three new seat bolts (8) and
lightly tighten seat bolts until the bolt heads touch
the retaining ring.
4. Apply a think film of FDA silicone grease such as
Dow Corning #7 to the exposed rubber surface
and close the valve so that the disc is level with
the flange face with in +/- ¼ in.
5. Tighten the seat bolts in a crossover pattern in two
steps to the torque given in Table 3 using a socket
wrench.
6. Cycle valve open and closed and verify that disc
closes within +/- ¼ in of center. Conduct a
pressure test, If necessary, tighten seat bolts ½
turn to stop any leakage.