Rotary screw compressors are a type of gas compressor, which employs a rotary type positive displacement mechanism. In rotary screw compressors, this mechanism utilizes either one or two counter rotating helical screw elements, housed in a specially designed chamber. As the mechanism within the rotary screw compressors rotate, the meshing and rotation produces a volume of reducing cavities. Gas is drawn into the casing, captured in the cavity, and is compressed as the cavity reduces in volume, this is then discharged from another port in the rotary screw compressors casing. Rotary screw compressors are used for a wide range of applications, such as to supply compressed air for general industry, air powered machinery, and units can be trailer mounted for use in the construction industry.