The rotary drum sieves are widely used for the classification of sand, soil, stone, organic compound, wood chips, and biomass in general, separating the fines and impurities. Composed of a long cylinder, inclined at 5° to 10° relative to the horizontal, which rotates at a low speed, usually between 10 and 25 RPM. The lateral surface of the cylinder can be a perforated metal plate or screen, with progressively larger openings towards the outlet, or with a unique opening. The residues that are deposited on the sieve from its side, while the sieve rotates, the residues that do not have the appropriate size end up passing through the sieve screen and falling out of the classifier, while the quality residues are discharged onto a conveyor belt.