Abstract: A multi-stage centrifugal chamber filter for separating solids from a gas stream. The filter has a plurality of separate multistage filter elements, each having at least one flow channel to which a plurality of centrifugal chambers is connected. The cross-section of the flow channel decreases in the direction of flow from chamber to chamber in order to provide a constant velocity of flow. The inlet and the outlet of the or each flow channel are designed to be in opposite end walls of the filter elements. A plurality of filter elements are located in a filter housing between two parallel walls spaced apart in the housing. Passages are provided in the walls for opposing inlets and outlets of the filter elements. The filter housing has at least one purified-gas outlet between the walls. The inlets and outlets of the filter elements are connected outside the walls to a crude-gas inlet and a residual-gas outlet respectively.