Abstract: The height positioning of the rotor (4) and thus the play between the wings (3) of the rotor and the sieve (5) of the machine are adjustable by means of an adjusting system (20-26), even during operation of the machine. The drive of the rotor (4) by a belt (19) allows to omit gears as well as an oil bath for the drive. The risk of a contamination of the granulated material by residues is thus obviated. The sieve (5) is supported on a retaining ring (6) which allows to adjust the height of the sieve in such a manner that the internal surface of the sieve is always at the same position independently of the thickness of the sieve. It is thus possible to adjust the play between the sieve and the rotor with precision.