The SM21 type hammer mill is used for grinding cereals, dried legumes, bran and cleaning waste.

A feeding box, with a safety device against foreign bodies, allows the product to enter the hammers chamber, where it is ground and centrifuged by freely oscillating beaters, made of very high resistance steel. The ground product, pushed by the centrifugal motion of the hammer rotor, passes through the perforated perimeter sheet and, thanks to a delivery star integral with the rotor, is launched tangentially towards the exit with a pressure of approximately 300 mm of water column.