Rotary drum sieves are widely used for the classification of materials such as sand, soil, stone, organic compost, chips, and biomass in general, separating fines and impurities. These sieves consist of a long cylinder, inclined between 5° and 10° in relation 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 a screen, with progressively larger openings in the direction of the outlet or with single openings.

The residues are deposited on the side of the sieve, and as 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.

In processes of automatic feeding of biomass boilers or furnaces, the separation of residues of different sizes is essential for greater productivity and durability of the equipment. The sieves perform this separation through their trapezoidal discs that vibrate the residues deposited on the splitter, allowing the separation of residues by size.

With disc sieves, it is possible to separate very small particles of residues, keeping only the particles with the necessary size for burning. These sieves separate residues such as chips, sawdust, wood residues, shells, sugarcane bagasse, among others, ensuring that only the appropriate material is used in combustion processes.