A rotary feeder includes a housing which accommodates a rotor including a plurality of vanes supported on a shaft. The rotary feeder is sealed in axial direction by slide rings which are acted upon by a pressure fluid and in radial direction by displaceable sealing strips which are contained in the peripheral end face of the vanes. The required contact pressure in axial direction as well as in radial direction is provided by a pressure fluid source which acts upon the annular piston-type slide rings. Each slide ring is pressed against a slide disk which is part of a lateral disk member of the rotor and is rotatable in circumferential direction to the slide disk. Each slide disk is provided in circumferential direction with slant grooves which are engaged by retaining bolts of a sealing strip unit contained in the peripheral end face of each vane and providing the radial sealing of the rotor vanes. The frictional force between the slide ring and the slide disk causes a rotation of the slide disk in opposition to the rotation of the rotor to thereby press the sealing strip unit in radial direction for generating a sufficient contact pressure for the radial sealing action.
