What we call the screw compressor is often referred to as double screw compressor.

In compressor host configuration in parallel with a pair of corresponding to the meshing of spiral rotor, usually with convex teeth on outside the pitch circle of the rotor (from cross section), known as the male rotor or Yang screw; The pitch has a concave tooth rotor (from cross section), called Yin or vaginal screw rotor.

A BanYang rotor as the active rotor, driven by Yang rotor Yin rotor rotation. The ball bearing rotor on the rotor to realize axial positioning, and axial force of the compressor. Tapered roller thrust bearing at the ends of the rotor make rotor radial orientation, and bear the radial and axial force of a compressor, the compressor host both ends with a certain shape and size of orifice, a call for inhaling inspiratory mouth, another call for exhaust vent.