Abstract: The invention relates to an air filter system comprising at least one drum filter, the surface area of this filter being provided with a filter medium, and a suction device for cleaning the inside of the surface area, wherein a driving device displaces at least one suction element for the cleaning process in circular motions along the inside of the surface area as well as axially in the direction of the longitudinal axis of the drum filter. It is provided that the drum filter (4) is disposed with the longitudinal axis (6) extending vertically.

Abstract: A fan having a rotor with a plurality of fan blades, the fan having an intake and a pressure side. A blocking device between the intake and pressure sides of the fan. The blocking device comprising a strip-like brush element with a plurality of brush sections that extend radially upwardly toward the edge of the rotor. The brush sections are spaced apart from one another along the direction from the intake to the pressure side of the fan. A cross-flow fan has spaced apart brush sections which are spaced apart in the running direction of the fan. An axial flow fan has brush sections which are spaced apart from one another transversely with respect to the running direction. The brush sections in each of the fans may also be as in the other type of fan. The brush sections may define a v-shape extending from a common block or may be in spaced apart rows or may be individual tufts and the tufts may be staggered along the length of the brush.