Reciprocating compressors use pistons driven by a crankshaft to squeeze gas into smaller volumes, thus increasing the pressure of the gas. The prime mover drives a shaft that is connected to the compressor crankshaft.
Reciprocating compressors can achieve higher pressure differentials than a single centrifugal unit, and they work well over a wide range of flow rates. But they require more maintenance and thus are more expensive over the long term. Reciprocating compressors are commonly coupled with a reciprocating engine as the prime mover but can also be used with an electric motor.