The drum of this machine is driven by the main motor. The variable - frequency auxiliary motor and the gearbox (or hydraulic motor) form the differential speed system between the drum and the screw. The drum and the screw rotate in the same direction at different speeds on the same axis. The suspension enters the drum through the fixed feed pipe and the screw discharge port. Under the action of the centrifugal force generated by high - speed rotation, the solid particles with a larger specific gravity settle on the inner wall of the drum. Under the action of the screw differential speed, the solid particles settled on the inner wall of the drum are continuously scraped off and pushed towards the small end of the drum, and then discharged from the slag discharge port. The liquid phase with a smaller specific gravity forms an inner liquid ring inside the drum, and is continuously clarified along the spiral groove and flows towards the large end of the drum, overflowing from the overflow weir plate with an adjustable diameter. Thus, the two - phase or three - phase separation of solid and liquid is achieved. The rotational speed of the drum and the differential speed between the drum and the screw can be steplessly adjusted according to the characteristics of the separated materials.