Rotor, grinding machine, air extraction casing, and grinding element for a grinding machine

A rotor (1) for a grinding machine (2) for the foodstuffs and feedstock industry, having an external diameter of between 0.5 and 0.6 m, comprising a plurality of substantially cylindrical, in particular hollow cylindrical, grinding elements (3). One such grinding element (3) has an outer grinding surface (4) substantially in the form of a circular cylinder jacket, and the grinding elements (3) are arranged coaxially above one another and in such a way that a substantially annular air gap (5) is produced between the grinding surfaces (4) of two adjacent grinding elements (3). A ratio between an enveloping surface (H) of the rotor (1) and a total grinding surface of the rotor (1) is greater than 1.05 and less than 1.25.