Most field compressors use hydrodynamic type or “journal” bearings. As shown in Figure 11-12, oil enters into the bearing from supply holes strategically placed along the bearing circumference and builds up an oil film between the stationary and rotating parts of the bearing. The oil flows axially and circumferentially along the bearing, then out the ends, As the oil flows through the bearing, the load compresses the oil film, generating the high pressure within the bearing that supports the load while allowing for rotation.
In a reciprocating compressor the bearing locations are:
* Main bearings—between crankshaft and frame
* Crank pin bearing—between crankshaft and connecting rod
* Wrist pin bearing—between connecting rod and crosshead
* Crosshead bearing (shoe)—underneath the crosshead