The twin-screw compressor is a two-shaft positive displacement rotary compressor. The main rotor of the main (male) pair (female) is matched to form a meshing pair. The main and auxiliary rotor teeth are externally formed with the inner wall of the casing to form a closed base. The volume of the volume, the shortage of the twin screw is that the 40 cubic meters and above models need to add speed increasing gears, increase power consumption and are prone to head lock; and the worm compressor is a single-shaft volumetric rotary compressor, which meshes The secondary is composed of a worm and two star planes arranged symmetrically. The worm groove and the star tooth surface and the inner wall of the casing form a closed element volume, but the shortage of the star wheel material needs to be improved.