The fine wedge (curved screen) is the purpose of an external high-speed pumping fluid material flowing into the arc mesh, relying on centrifugal force and gravity of the water in the sieve gate relative shear movement, separating the solids and liquids to sieve. The same time, the online gathering solids, with the flow rolling down liquid continuously hydraulic erosion sieve gate, making it play a role in self-purification, thus completing the whole process of sieve continuous self-purification and solids collected.