Flowserve Valtek Installation, Operation & Maintenance Instructions Manual page 11

Table II:
Extended Plug to Bonnet Dimensions
(refer to Figure 5)
Valve Size Stroke
(inches) (inches)
1 / , 3 / , 1 1.00
2 4
1
1 / , 2 1.50
2
3, 4, 6 2.50
(class 150)
16. For correct stem engagement on air-to-close valves,
a check valve must be used to lock air into the top
of the actuator. This puts the actuator stem in the
extended position. Turn the actuator stem onto the
bellows seal stem until about
left between the bottom of the yoke and the shoul-
der of the bellows seal bonnet. Carefully exhaust
the check valve and the yoke will come into contact
with the bonnet. This will provide the proper clear-
ance between the piston and the top of the yoke.
17. Attach the yoke clamps.
18. Using new seat and bonnet gaskets, replace the
seat ring and seat retainer in the body.
Failure
Leakage through 1. Insufficient compression of housing
lower housing
clamps or flanges 2. Worn or defective lower housing
Leakage through 1. Insufficient compression of seal ring
upper housing
clamps or flanges 2. Worn or defective upper seal ring
Leakage through 1. Insufficient compression of bonnet
bonnet gasket
2. Worn or defective bonnet gasket
Leakage through 1. Failure of metal bellows seal
packing box or
"tell-tale" tap
Valve does not
seat or seats 2. Improper actuator stem
too early
Distance Between
Extended Plug
and Bonnet
1.03
1.56
2.56
1
/ -inch of space is
16
Troubleshooting Formed Metal Bellows Seals
Probable Cause
gasket
gasket
gaskets
gaskets
gasket
assembly
1. Loose stem locknut on plug stem
engagement
19. Install the entire actuator/bellows seal subassem-
bly into the valve body. Tighten the bonnet flange
bolting finger-tight.
20. Apply air pressure over the piston while exhausting
the other side to seat the valve.
opposing bonnet flange bolts or nuts
flat). Tighten each bonnet bolt in this manner until
the bonnet bottoms metal-to-metal in the body.
This can easily be felt through the wrench.
21. Release the air in the cylinder. Firmly tighten the
upper and lower housing clamps or flanges by
tightening two opposing bolts, so that even pres-
sure on the gasket and proper alignment of the
housing and body bonnet are maintained.
22. Adjust the stem clamp to the correct position ac-
cording to the air action (air-to-open valves should
be adjusted so that the stem clamp points to
"closed" on the stroke indicator plate; air-to-close
valves should point to "open").
23. Attach the packing box bolting and tighten the
packing box nuts to slightly over finger-tight.
CAUTION: Do not overtighten packing. This
can cause excessive packing wear and stem
friction which may impede stem movement.
24. Stroke the valve and check for smooth operation.
Corrective Action
1. Tighten flanges or clamps until leakage
stops
2. Disassemble and replace lower housing
gasket
1. Tighten flanges or clamps until leakage
stops
2. Disassemble and replace upper seal
ring gaskets
1. Tighten bonnet flange bolting until
leakage stops
2. Disassemble and replace bonnet gasket
1. Disassemble and replace metal bellows
seal assembly and all gaskets
1. Disassemble, tighten stem locknut
2. Correct stem engagement (refer to steps
15 and 16 in the "Reassembly" section)
Tighten two
1 / - turn (one
6
12-11