A filter cassette for removing particles from an air stream is provided, The filter cassette has an upstream end, a downstream end, and includes a mounting frame to which a filter media is fitted. The filter has a mounting face positioned between the filter cassette's upstream and downstream ends at a first distance (Dup) from the upstream end and a second distance (Ddown) from the downstream end. The first and second distances each amount to more than 10% of an overall length of the filter cassette. The mounting face may be positioned centrally between the upstream and downstream ends, approximately in a barycenter line of the filter cassette. The filter cassette thus extends to both sides of the partition opening. Filter surface area is increased and torque induced by the filter cassette into the partition is reduced.