Three-phase centrifugal separator utilizes the centrifugal sedimentation principle for oilAn effective separation device for continuous separation of water and sludge. The centrifuge starts rotating at full speed, and the slurry is added into the spiral inner drum through the feed pipe, then flows into the drum. Under the action of centrifugal force, the heavier solid sludge settles to the wall of the drum, and is pushed towards the small end of the drum by the spiral conveyor, and discharged through the slag outlet; oil and water form concentric rings, the lighter liquid phase (oil) overflows from the light phase liquid outlet, while the heavier liquid phase (water) flows into the pump chamber at the large end of the drum and is discharged by the centrifugal pump. The thickness of different liquid rings is adjusted by the variable centrifugal pump wheel.