Abstract: A method for producing a tight joint between a multi-layer synthetic resin material and a filter medium by selectively melting a layer of the synthetic resin material which has a different thermal absorption capacity in comparison with the other layers by heating the synthetic resin material with infrared radiation, and then fusing the melted synthetic resin layer to the filter medium. A filter element produced by the method of the invention is also disclosed.

Abstract: An air filter for internal combustion engines and interiors of motor vehicles has a filter insert in the form of a bellows of filter material folded in a zigzag shape by a first folding, wherein the bellows has a plurality of neighboring pockets extending in a longitudinal direction of the bellows, wherein between the pockets first folds are formed at ridges between the pockets. A seal is connected to the bellows. The folded filter material has a second folding in a direction transverse to the longitudinal direction and second folds are formed by the second folding that extend substantially transversely to the longitudinal direction. End faces extending transversely to the longitudinal direction are formed by cutting the bellows to a desired length. The seal extends across the end faces and longitudinal sides of the bellows.

Abstract: A filter element (1) with a tubular folded bag (2) of folded filter material, which has a plurality of fold blades (3) adjacent each other in the longitudinal direction (10) of the folded bag (2) a closure cover (4) is attached at at least one axial end (7) of the folded bag (2). In order to provide a filter element which can be bent to any desired curved form while maintaining a high degree of filtration performance, and can be produced in a cost effective manner, the fold blades (3) of a folded bag (2) are provided with a combination of diagonal folds extending at an angle relative to each other such that the fold blades (3) in the longitudinal direction (10) of the folded bag extend back and forth and thereby form a three-dimensional crown structure (18). At least the outer margin of the closure cover (4) has a form corresponding to the crown structure (18) of the fold blades (3).

Abstract: A filter element (1) with a tubular folded bag (2) of folded filter material, which has a plurality of fold blades (3) adjacent each other in the longitudinal direction (10) of the folded bag (2) a closure cover (4) is attached at at least one axial end (7) of the folded bag (2). In order to provide a filter element which can be bent to any desired curved form while maintaining a high degree of filtration performance, and can be produced in a cost effective manner, the fold blades (3) of a folded bag (2) are provided with a combination of diagonal folds extending at an angle relative to each other such that the fold blades (3) in the longitudinal direction (10) of the folded bag extend back and forth and thereby form a three-dimensional crown structure (18). At least the outer margin of the closure cover (4) has a form corresponding to the crown structure (18) of the fold blades (3).

Abstract: A cylindrical filter element which comprises a folded filter medium, in particular having a pleated configuration, which is annularly secured to a hollow cylinder, two expanded film axial end plates, and a support tube which is integrated into the cylindrical filter element and upon which the folded filter medium may be affixed. The support tube has an annular components adjacent respective axial end plates which has an interlocking fit with the film end plates and which may be connected to a sealing element.

Abstract: A method for producing a tight joint between a multi-layer synthetic resin material and a filter medium by selectively melting a layer of the synthetic resin material which has a different thermal absorption capacity in comparison with the other layers by heating the synthetic resin material with infrared radiation, and then fusing the melted synthetic resin layer to the filter medium. A filter element produced by the method of the invention is also disclosed.

Abstract: A filter cartridge which has an insertable center tube including an upper part (13) and a lower part (14) which can be coupled together in the cartridge by a snap fastener (21). The snap fastener (21) is configured such that it can be made without undercuts by simple injection molding dies. Therefore the filter cartridge with the center tube according to the invention is very economical.

Abstract: A filter element including an annular support body, a filter medium, which is preferably a filter paper folded in a zigzag shape, positioned on the annular support body, and end disks, which are positioned on the axial end faces of the filter medium and glued or welded to the filter medium. The filter element is characterized in that a seal carrier is provided on the support body in the vicinity of one or both end disks, and a seal, particularly an elastomer seal, is affixed to the seal carrier in an interlocking manner. The seal carrier is designed to be radially elastic. The filter of the invention is particularly suitable for filtering liquids.

Abstract: A cylindrical filter element which comprises a folded filter medium, in particular having a pleated configuration, which is annularly secured to a hollow cylinder, two expanded film axial end plates, and a support tube which is integrated into the cylindrical filter element and upon which the folded filter medium may be affixed. The support tube has an annular components adjacent respective axial end plates which has an interlocking fit with the film end plates and which may be connected to a sealing element.