Refer to Figure 300-1 for a single-cylinder compressor. However, most reciprocating compressors are multi-stage (refer to Figure 300-39). Even single-stage machines are often multi-cylinder for better balance. There are numerous arrangements of the cylinders. Figure 300-38 covers most of the possible arrangements. The horizontally opposed machine shown in the lower right-hand corner of this Figure is the most widely used configuration. Figures 300-39 and Figure 300-40 show other views of typical horizontally opposed machines.
The integral gas engine shown in Figure 300-38 is still popular for many oil field duties. A cutaway view is shown in Figure 300-41. Figure 300-42 illustrates an integral-engine compressor.