Paper brings a description of free motion of particles suspended in the atmospheric air and being under action of the gravitational field together with additional accelerations caused by their relative motion. Theoretical part of the paper presents physical background of the particles motion within rotating channels together with the simplified method allowing to determine efficiency of the dust separator. Experimental part of the paper describes the test stand layout together with details of the dust separator design and its principles of action. In the closing part final conclusions and suggested practical applications of the devices under investigation are presented.