Filter plate immersed in the pulp while in operation produces a surface absorption of filter cake, with the action of capillarity and integrated with vacuum pressure. Filtrate enters distributing valve and drainage tank through filter plate. Filter cake comes out from slime hopper receiving spray washing. Filter cake falls into the tank by the pressure from the wind and scraper. It can be used for floating and dewatering in clean coal and fine materials like tailings, and it can be also used in metallurgy, chemical, petroleum, sewage treatment, and other aspects of the solid-liquid separation.