Page 123 - Reciprocating Compressors Operation Maintenance

1 1 O Reciprocating Compressors: Operation and Maintenance

Full Pressure Circulation Lubrication

In this system, as shown in Figure 3-2, a positive displacement pump
draws oil from the reservoir and delivers it under pressure to the main
bearings and to the crankpin bearings, and hence to the crosshead pin
bearings and crossheads.
Oil is drawn up from the crankcase sump through a strainer to the oil
pump, and forced through the oil filter. From the oil filter, the oil is led
under pressure to the crankshaft. The main bearings are lubricated by
drilled passages in the main bearing saddles. The oil is forced through
drilled passages in the crankshaft and the connecting rod to lubricate the
crankpin bearings, crosshead pin bushing, and the crosshead slide.
Pressure circulation systems are equipped with suction strainers and
pressure relief or control valves. Oil filters, usually of the full-flow type,
and pressure gauges are also provided. On larger machines where large
quantities of oil are being circulated, oil coolers are provided. Oil pres-
sure safety devices are incorporated in the system to shut the compressor
down in the event of oil pressure failure.
Compressor crankcases are designed to exclude dust and other
contaminants and to prevent oil leakage. All access openings have tight

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FIGURE 3-2. Full pressure circulating lubrication system (Source: Dresser-
Rand, Painted Post, New York).