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Baker Hughes
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4. Adjustment
The air valve is normally factory set and does not require adjustment.
If it becomes necessary to
adjust set pressure:
A)
Turn adjusting screw (19) to relieve range spring (23) of air valve from compression.
B)
Connect air supply
to “IN” of body to check for closing and opening of body, then connect
pressure gauge and pressure regulator to the signal pressure connection "SIG IN".
C)
Turn on air supply pressure and adjust the pressure regulator to set the pressure at a desired
value,
observing the air supply pressure to “SIG IN” on the pressure gauge. Then turn the
adjusting screw clockwise until there is no air leak from "OUT" of body. At this point, the air
valve has its "IN" closed and "OUT" and "EHX" communicated.
D)
Finally, tighten adjusting screw locknut (20) and connect the air valve outlet and "OUT" to the
actuator and the signal pressure line to the supply pressure.
5. Maintenance
If the air valve does not operate properly, inspect it as follows.
A) Shut off the supply pressure
B) Return the adjusting screw to its former position and loosen the spring.
Disassembling Procedure
Remove four screws (25) and remove O-Ring (15), housing S/A, range spring (23), spring button
(17) and spring case (18) from body (1).
For housing (2), diaphragm S/A (16) and pilot valve (6) can be removed by loosening nut (21) and
pilot retainer (7) respectively.
To disassemble body S/A, first remove bottom cap (26), take out spring (9), remove nut (24) on the
underside of plug S/A and pull out spring washer (22), insert retainer (5) and rubber insert (8).
After that, push up the bottom or plug (3) to remove piston (4) and rubber insert (8) together with
plug.
Inspection should be made in the following way:
First examine diaphragm (16) for rupture and damaged edge. Inspect the seat of pilot valve (6) for
dust and damage. Also inspect O-rings (13) and (14). Replace all of these parts by new ones if
necessary. For the valve body, inspect O-rings (10), (11), (12) and (15) and rubber insert (8).
Replace them with new ones if necessary.
Check the valve seat for dust and clean it.
6. Reassembly
Reverse the disassembly procedure. Before setting to reassembly, apply silicon grease to O-rings.
Do not fail to use a new shim (27).
