Abstract: A rotary feeder includes a housing which accommodates a rotor extending between two lateral disk members. Bearing against the peripheral area of each disk member is a slide ring which is acted upon by a pressure fluid with a constant holding force by which the slide ring is pressed against the associated disk member. Thus, the axial sealing of the rotor within the housing is independent of the wear of the slide ring. In addition to the holding pressure, the slide rings may also be subjected to a momentary displacement force which exceeds the holding force and ensures that the slide rings overcome frictional forces in the area of their guides.