Abstract: A filter element includes a pleated filter medium including pleat valleys and pleat walls. The filter medium has a base body including a first flank and a first plastic reinforcement joined to the first flank of the pleated filter medium and accommodating the pleat valleys and pleat walls of the filter medium.

Abstract: A method is provided for connecting a filter medium to a connection element, wherein the filter medium and the connection element are brought into contact with each other and connected to each other by exposure to laser radiation. The connection element may be welded to the end faces of filter folds in strips having a width of 1 mm. The connection element may include a laser light-absorbing layer and a laser light-transparent layer. The filter medium and connection elements may comprise nonwoven fabrics.

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.