Abstract: A filter bag for pocket air filters has two abutting side parts which are made of an air-permeable filter material that is weldable by ultrasound. The side parts are continuously welded to one another in side edge portions on three sides of the side parts so that a pocket having two opposite side edges, a bottom edge and an opening opposite said bottom edge is formed. Several webs made from a flexible material web are formed in the pocket. The webs connect the side parts to one another and are orientated from an opening side of the filter bag in the direction of the bottom edge. The flexible material web is alternately connected—at least in portions—to one of the side parts in each case in weld portions. The weld portions are delimited by at least one weld across the direction of flow.

Abstract: The invention relates to a filter bag (1) for pocket air filters having two abutting side parts (2, 3) which are made of an air-permeable filter material that is weldable by ultrasound. The side parts (2, 3) are continuously welded to one another in side edge portions (4) on three sides (5, 6, 7) of the side parts (2, 3), so that, by way of the two side parts (2, 3) welded together, a pocket (8) having two opposite side edges (9, 10), a bottom edge (11) and an opening (12) opposite said bottom edge (11) is formed. Several webs (13) made from a flexible material web (14) are formed in the pocket (8). The webs (13) connect the side parts (2, 3) to one another and are orientated from an opening side (15) of the filter bag (1) in the direction of the bottom edge (11). The flexible material web (14) is alternately connected—at least in portions—to one of the side parts (2, 3) in each case in weld portions (16).