The residence time of each product can be adjusted by the radial direction and the tangential angle of the swinging screen. Then, established the level and throwing three-dimensional tumbling motion. From the center to the outer edge in the sieve surface is uniformly dispersed, to in a spiral motion to the axial propagation. Thus fine particles complete the whole screening process. Horizontal and vertical acceleration with the movement of the material increased, and close to the aperture size of particles subsequently successfully separated, larger particles were transported to the exit, the outlet is controlled by an adjustable guide device, which is another factor that controls the retention time of the material. The process is repeated among each layer of screen.