Model PTD centrifuges are three-column top discharge, intermittent operation filtrating equipment. The material is fed into the drum at the top; under the action of the centrifugal force field., the liquid-phase passes through the filter medium and the discharged out of the machine, while the solid-phase material is retained inside the drum and, after the machine is stopped, the material is discharged from the top. The centrifuge has such features as simple structure,  easy operation, no easy breakage of material as well as good versatility.