Screw Compressors

Screw compressors are perforce twin-shaft rotating lobe machines. They work on the positive displacement principle with internal compression and are so-called compulsive conveyors. They are commonly used to replace piston compressors where large volumes of high-pressure air are needed.  Either for large industrial applications or to operate high-power air tools such as jackhammers and impact wrenches. For smaller rotor sizes the inherent leakage in the rotors becomes much more significant. Leading to this type of mechanism being unsuitable for small air compressors.

The gas compression process of a rotary screw is a continuous sweeping motion, so there is very little pulsation or surging of flow, as occurs with piston compressors. This also allows compressors to be significantly quieter and produce much less vibration than piston compressors, even at large sizes, and produces some benefits in efficiency.

Screw compressors can be either twin helical screws or a single screw design. They can be open drive, semi-hermetic, or hermetic in configuration. In addition, there are oil-flooded compressors and non-oil (dry) compressors. Screw compressors are designed to work in a wide variety of applications including, but not exclusively limited to, refrigeration, comfort cooling, open loop gas processes, and air compression.