Abstract: A three-dimensional object folded from a flat work piece, particularly a filter element folded from a nonwoven fabric, characterized in that the three-dimensional object (20) is made up of several rows (5, 6, 7) of hollow pyramid elements (30) that are joined in rows and nested into one another.

Abstract: A three-dimensional object folded from a flat work piece, particularly a filter element folded from a nonwoven fabric, characterized in that the three-dimensional object (20) is made up of several rows (5, 6, 7) of hollow pyramid elements (30) that are joined in rows and nested into one another.

Abstract: A dust filter bag made of a fiber layer laminated together with a paper layer. The fiber layer is made of synthetic polymer fibers and is arranged on the downstream side of the paper layer. To increase the strength of the dust filter bag, the fiber layer contains melted polymer regions and by way of the polymer regions the fiber layer is additionally consolidated within itself and joined to the paper layer. The polymer regions have a welded area of 0.5 to 10% of the surface area, preferably 1 to 3%, thus resulting in sufficient laminate strength with a low pressure drop.

Abstract: A filter cartridge having a flexurally rigid frame with a filter element inserted therein is formed of a frame composed of a blank in a single piece, and is folded inward forming a double-walled box profile.

Abstract: A filter insert. The filter insert includes an accordion fold pack that is made of a filter material and is joined to a filter frame. The material of the filter frame is injected in a flowable state into the folds of the accordion fold pack which are open in the on-coming flow direction of the medium to be filtered. The material is subsequently hardened during automatic claw fixation with the fold walls. The entire peripheral edge of the accordion fold pack sealingly overlaps the outer boundary surfaces of the filter frame, and is designed as a sealing device.

Abstract: A method for manufacturing a filter insert, and the filter insert so manufactured. The filter insert includes an accordion fold pack that is made of a filter material and is joined to a filter frame. The material of the filter frame is injected in a flowable state into the folds of the accordion fold pack which are open in the on-coming flow direction of the medium to be filtered. The material is subsequently hardened during automatic claw fixation with the fold walls. The entire peripheral edge of the accordion fold pack sealingly overlaps the outer boundary surfaces of the filter frame, and is designed as a sealing device.

Abstract: A flexible folded filter insert which is not noticeably deformed by the air which it cleans. The insert has a fold pattern which is closed off at the ends by flexible strips which can be compressed in the longitudinal direction.

Abstract: A filter insert of nonwoven material in the form of a pleated pack is self-supporting and consists of thermally weldable nonwoven (1). Each of the two outside ends (3) of the pleated pack (2) is hemmed by the nonwoven material (1) forming the pleats, which is folded over in the same direction and at the same time is fixed in tight contact to the corresponding folded of the adjacent pleat end. At the same time the nonwoven material projects beyond the near crease of the adjacent pleat end by 0.5 to 1.5 times the pleat spacing. For manufacture, the flat filter material (1) is first pleated and then a defined pleat spacing (7) is produced by drawing it apart to a limited extent. Then the two outside edges (8) of the pleated pack are gripped between comb-like tools (9) entering pincer-wise into the pleating at top and bottom, leaving the filter material projecting beyond the tools on each side by 1.5 to 2.5 times the pleat spacing (7).

Abstract: A filter pack for gas and/or liquid filtration employing filter medium surfaces disposed between pairs of spacers, with the spacers having a corrugated configuration and the edges of the corrugations of each spacer preferably being mutually parallel to one another, the improvement wherein the edges of the corrugations of the spacers placed adjacent to the two sides of one filter medium surface are locally oriented at an angle toward one another.