Different solid granularities have different gravity and thus have different dropping speed. The fine ore granularities floating in the water will overflow and the big ones will sink to the bottom and discharge from the upper part by spiral pushing. It can filter the granularities from the machine and then spin the rough particles to charging part by spiral vane and discharge the fine granularities from the overflow pipe. The base of the machine adopts a channel steel and the body adopts welded steel plate. The water inlet of spiral axle and axle head adopt pig iron cover for wear proofing and long life operation. The lifting equipment has two types, manual control and electric control.