Compressor

For other uses, see Compressor (disambiguation).
A small stationary high pressure breathing air compressor for filling scuba cylinders
A powerful compressor for street work. Model XASS from Atlas Copco circa 1985.
Natural gas compressor at a gas well
High pressure reciprocating compressor from Belliss and Morcom, used in the bottling industry

A compressor is a mechanical device that increases the pressure of a gas by reducing its volume. An air compressor is a specific type of gas compressor.

Many compressors can be staged, that is, the gas is compressed several times in steps or stages, to increase discharge pressure. Often, the second stage is physically smaller than the primary stage, to accommodate the already compressed gas without reducing its pressure. Each stage further compresses the gas and increases its pressure and also temperature (if inter cooling between stages is not used).