An apparatus for separating materials with different flowability has a rotationally driven hollow drum with a perforated peripheral surface, stripping means for stripping away material, and a continuous compression belt pressed from outside onto the drum by wrapping around part of the circumference of the drum, an intake wedge for the material. The belt is mounted by a drive roller and bearing roller. The drive roller controllably variably presses into a pressing position against the drum, separated by the belt. The drive roller position is adjustably set by a first positioning device via a control device, with a first end abutment element for mechanical position limitation. Part of the first positioning device comes into blocking contact with a first counter-surface of the first end abutment element in the pressing position of the drive roller and the first counter-surface of the first end abutment element is adjustable by the control device.