Baker Hughes Masoneilan 4700P, Инструкция по эксплуатации

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Masoneilan 4700P/E & 4800P/E Positioners Manual | 47 © 2021 Baker Hughes Company. All rights reserved.
Maintenance
WARNING
Before commencing any calibration or maintenance
procedure on these positioners, ensure that the valves
under control are isolated from the controlled process
and that the area is verified as nonhazardous.
Pilot
See Figure 17 .
To clean or replace deteriorated parts, the valve must be isolated from process. Shut off air
supply. To minimize maintenance time, it is recommended that the entire pilot subassembly (11)
be replaced by a new subassembly, so that the old unit can be worked on when time permits.
Disassembly
1. Unscrew the pilot subassembly (11) and disengage it from the body (1). Note: Turn the
pilot subassembly while removing it to prevent damage to the O-rings.
2. Remove end plug and withdraw the spring, plug and extension pin. If necessary, use a
penetrating oil to free parts.
CAUTION
Do not disassemble or adjust extension pin.
3. Wipe the parts with a clean soft lint free cloth and blow compressed air through the
orifices. Use isopropyl alcohol to clean. Do not use chloride based solvents.
Reassembly
1. Install three new O-rings on the pilot spool. Put a light coating of silicone grease on each
O-ring.
2. Replace the extension pin and the plug, countersunk end first into the pilot spool. The plug
should slide into the pilot spool by its own weight.
3. Install the spring in the pilot spool. The end having the smallest diameter must be in
contact with the plug. Screw the pilot end plug into the pilot spool.
4. Install the pilot subassembly (11) into the body (1).