1,061,522. Centrifugal separators. T. B. LOFTHEIM. Feb. 28, 1964, No. 8566/64. Heading B2P. In a dust, &c. separator of the centrifugal type comprising a rotor 1 having whirl-forming separation blades 3 distributed around the axis of rotation and inclined outwardly relative to that axis from the inlet end towards the outlet end of the rotor, the spaces between the blades forming primary passages 4 communicating at the periphery of the blades with primary outlets 5 through which cleaned gas is emitted into a primary housing 10, the spaces 4 between the blades have extensions 6 bounded by plate portions 7 which extend from the inner side edges 3' of respective blades in a direction opposite to that of the rotor, and at least partly overlap each other. The plates preferably extend beyond the rear edges of the blades 3 and form outlets 9 for dustcontaining gas which project into a secondary housing 13 having an outlet (not shown) to a dust collector or secondary housing. Each plate portion 7 along its free edge may have an outwardly bent edge portion 8 which engages an adjacent plate portion on a subsequent blade thereby providing the extensions 6 with a trough-shaped configuration. The dust-laden gas is supplied through an inlet 3. Separation takes place in the spaces 4 between the blades due to rotation of the rotor and to the whirling effect induced by the blades. The clean gas discharges at 5 while the remainder of the gas and the dust are received in the extension 6 and are conveyed along same to the outlets 9.