Page 333 - Reciprocating Compressors Operation Maintenance

318 Reciprocating Compressors: Operation and Maintenance

Force-Feed Lubricator

Incorrect Delivery of Lubricator

1. Feeds not vented of air
2. Low oil level
3. Plugged vent in lubricator reservoir
4. Oil check valve on cylinder faulty
5. Line leaking or kinked
6. Incorrect adjustment of pump stroke
7. Leak in line or fitting

Troubleshooting charts similar to Table 5-1 are useful aids in pinpoint-
ing problems. Two charts, Tables 5-2 and Table 5-3 have different but
complementary approaches; one helps to locate the problem, and the
other helps identify what caused it.

Regularly observing the intercooler pressure is important in the deter-
mination of proper compressor performance and operation.

SUCTION VALVE FAILURES

As has been pointed out, capacity loss can most often be attributed to
problems with valves. If a suction valve does not close and seal com-
pletely, the following occurs:

1. During the compression (discharge) stroke, some of the normally
displaced gas will leak or blow by the suction valve to the suction
side of the valve.
2. The volume of gas actually displaced will decrease.
3. As the compressed hot gas passes over the valve in the wrong direc-
tion, the valve heats up.
4. The inlet temperature of the gas on the suction side of the valve
goes up, thus reducing the volumetric efficiency of the machine,
that is, hotter than normal design suction temperatures will result.

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