ABSTRACT
A compressor is a power-driven mechanism for raising the pressure of a gas by doing work on it. Air is the most plentiful gas, and it is compressed more extensively than any other. Most of this discussion will therefore deal with the compression of air, though many of the principles involved apply also to the compression of other gases. The lubrication requirements of reciprocating compressors can be divided into two parts, the requirements of the cylinders and those of the bearings. Generally, in the small single-acting compressors the crankcase forms a reservoir for the lubricating oil which lubricates both bearings and cylinders. Lubrication of the cylinders is usually carried out by oil splash, excess oil draining by gravity to the crankcase. Lubricating oil is fed direct to the cylinder walls at one or more points by some form of mechanical force-feed lubricator. By this means precisely metered quantities of once-through lubricant are continually replenished on the cylinder walls.
