Abstract: A disintegrator includes a grinding chamber (1) accommodating grinding rotors. The housing of the chamber (1) includes a cylindrical portion (7) having an outlet pipe (19) for evacuating the material and two side walls (9 and 10) one of which, particularly wall (9) has a feeding pipe (12). The cylindrical portion (7) can be turned relative to the side walls (9 and 10) the desired position being fixed by locking assemblies (11) arranged about the periphery of the cylindrical portion (7). Each locking assembly (11) includes a pressure plate (13). One end of the pressure plate (13) bears on a projection (15) provided on one of the side walls (10), whereas the other end is received by an annular groove (16) made on the outer surface of the cylindrical portion (7) of the housing. In addition, the plate (13) is secured to the side wall (10)having the projection (15) by a bolt ( 14).