Reciprocating compressors work by drawing gas into a cylinder through a suction valve when a piston moves downward. When the piston moves upward, it compresses the gas and forces it out of a discharge valve. George Medhurst designed the first motorized reciprocating air compressor in 1799. There are two main types: reciprocating compressors and centrifugal compressors. Reciprocating compressors can be single-acting or double-acting, and single-stage or double-stage. They are commonly used when high compression ratios are required without high flow rates, such as in bottling plants and gas stations.