A filter system comprising: a housing comprising a tubesheet separating the housing into a dirty air chamber and a clean air chamber; a plurality of spacer elements attached to the tubesheet, wherein each spacer element of the plurality of spacer elements comprises a clean air inlet and a clean air outlet, and wherein the clean air inlet of each spacer element of the plurality of spacer elements is located in the dirty air chamber; a plurality of apertures in the tubesheet, wherein each spacer element of the plurality of spacer elements is positioned over an aperture of the plurality of apertures in the tubesheet such that air passing from the dirty air chamber into the clean air chamber through each spacer element of the plurality of spacer elements passes through the aperture; a plurality of filter elements, wherein each filter element of the plurality of filter elements is attached to the clean air inlet of one spacer element of the plurality of spacer elements; and a dirty air inlet (11; 111) attached to the housing, wherein the dirty air inlet (11; 111) is configured to deliver a dirty air stream into the dirty air chamber, wherein the dirty air inlet (11; 111) is configured to deliver the dirty air stream into the dirty air chamber along a dirty air flow axis, and wherein the dirty air flow axis extends through or passes at least one spacer element of the plurality of spacer elements at a location between the clean air inlet and the clean air outlet of the at least one spacer element such that dirty air entering the dirty air chamber along the dirty air flow axis contacts or passes at least one spacer element of the plurality of spacer elements at a location between the clean air inlet and the clean air outlet of the at least one spacer element before contacting the plurality of filter elements, and a hopper, below the dirty air chamber, configured to collect particulate matter separating from the dirty air stream, characterized in that the housing comprises: an end wall panel located across the dirty air chamber from the tubesheet, wherein each spacer element of the plurality of spacer elements and the filter element attached to each spacer element extend across the dirty air chamber from the tubesheet to the end wall panel, and an upper wall panel to which the dirty air inlet (11; 111) is attached, such that - in use - some of the particulate matter in the dirty air stream is deposited directly in the hopper without ever reaching the filter elements. a housing comprising a tubesheet separating the housing into a dirty air chamber and a clean air chamber; a plurality of spacer elements attached to the tubesheet, wherein each spacer element of the plurality of spacer elements comprises a clean air inlet and a clean air outlet, and wherein the clean air inlet of each spacer element of the plurality of spacer elements is located in the dirty air chamber; a plurality of apertures in the tubesheet, wherein each spacer element of the plurality of spacer elements is positioned over an aperture of the plurality of apertures in the tubesheet such that air passing from the dirty air chamber into the clean air chamber through each spacer element of the plurality of spacer elements passes through the aperture; a plurality of filter elements, wherein each filter element of the plurality of filter elements is attached to the clean air inlet of one spacer element of the plurality of spacer elements; and a dirty air inlet (11; 111) attached to the housing, wherein the dirty air inlet (11; 111) is configured to deliver a dirty air stream into the dirty air chamber, wherein the dirty air inlet (11; 111) is configured to deliver the dirty air stream into the dirty air chamber along a dirty air flow axis, and wherein the dirty air flow axis extends through or passes at least one spacer element of the plurality of spacer elements at a location between the clean air inlet and the clean air outlet of the at least one spacer element such that dirty air entering the dirty air chamber along the dirty air flow axis contacts or passes at least one spacer element of the plurality of spacer elements at a location between the clean air inlet and the clean air outlet of the at least one spacer element before contacting the plurality of filter elements, and a hopper, below the dirty air chamber, configured to collect particulate matter separating from the dirty air stream, characterized in that the housing comprises: an end wall panel located across the dirty air chamber from the tubesheet, wherein each spacer element of the plurality of spacer elements and the filter element attached to each spacer element extend across the dirty air chamber from the tubesheet to the end wall panel, and an upper wall panel to which the dirty air inlet (11; 111) is attached, an end wall panel located across the dirty air chamber from the tubesheet, wherein each spacer element of the plurality of spacer elements and the filter element attached to each spacer element extend across the dirty air chamber from the tubesheet to the end wall panel, and an upper wall panel to which the dirty air inlet (11; 111) is attached, such that - in use - some of the particulate matter in the dirty air stream is deposited directly in the hopper without ever reaching the filter elements.