A device for comminuting feed material is provided that has a housing including longitudinal walls and transverse walls for accommodating a rotor that rotates about a longitudinal axis. The rotor is equipped about its circumference with processing tools, and has, on its faces, an annular disk, each of which is concentric to the longitudinal axis. Within the housing, at least one screen path extends over a part of the circumference of the rotor, each screen path running at a slight radial distance from the annular disks while forming a seal gap. The feed material is supplied to the rotor through a feed shaft and is directed out of the device via a material discharge extending downstream of the screen path. In order to return material that emerges through the seal gap to the remaining material flow annular disks are each arranged with an axial clearance A from the transverse walls.