The rotary screen is an additional system to separate a pre-defined grain size. Horizontally mounted inside a solid steel structure and supported by wheels inside turned tracks, it generates a rotary motion that shakes the material inside it. Interchangeable perforated sheets are usually mounted around the edges of the rotating drum and the inlet section material can be of different diameters with respect to the outlet portion. The drum is rotated by an electric motor or hydraulic unit and can be tilted to optimize and lengthen the time the material spends inside it. The conveyor below it receives the material exiting the screening plates and conveys it to a single point for subsequent processing.