The compressor cylinders, also known as stages, of which a particular design may have from one to six or more, provide confinement for the process gas during compression.
Cylinders for larger applications (typical cutoff is 300 hp) are equipped with coolant passages for thermosyphon or circulating liquid coolant-type systems, whereas some smaller home and shop compressors are typically air-cooled. Large application cylinders are generally fitted with replaceable liners that are press-fitted into the bore, and may include an antirotation pin.
Process gas is drawn into the cylinder, squeezed, contained and then released by mechanical valves that typically operate automatically by differential pressures. Depending on system design, cylinders may have one or multiple suction and discharge valves.
