This type is mainly used for solid-liquid-liquid separation, which means to separate a solid phase (with its density being the maximum) with two liquid phases of different densities. Based on a certain differential, the bowl and spiral revolve in the same direction at high speeds, and the materials enter the equipment through the feeding pipe. Under the action of centrifugal force, the solid matters will deposit to form a sediment layer on the bowl wall, and the two liquid phases will form a light liquid ring and a heavy liquid ring respectively, successively forming a solid layer, light liquid layer and heavy liquid layer inward from the bowl wall. The spiral works continuously to push the solid matters on the bowl wall to the conical end of the bowl and then discharge them out of the equipment through the slag discharging port. The light liquid phase continuously flows out of the overflow port at the big end of the bowl, while the heavy liquid phase is discharged out through the centripetal pump also at the big end. Thus, continuous separation of three phases is realized.