Filter cartridge made of an accordion fold pack folded in a zigzag-shaped manner and method for its manufacture

The present invention relates to the improvement of filter cartridges made of an accordion fold pack folded in a zigzag-shaped manner that are made of a thermoplastically moldable and heat-sealable material. In filter cartridges of this type, the folds are held at an adjusted, defined distance relative to each other, and are made of a nonwoven fabric. Filter cartridges of this kind are used, for example, in vehicles to filter the passenger compartment air or also as an engine supply air filter. A recurring problem in these filters is the difficulty of providing regular fold spacing and consequently an unvarying, uniformly good filtering action across the entire filter surface. During the installation of the filter or during use, the fold spacings can be changed unintentionally, resulting in a reduced filter action. A filter cartridge made of an accordion fold pack folded in a zigzag-shaped manner and made of a thermoplastically moldable and heat-sealable material, whose folds are held at an adjusted, defined distance relative to each other, in particular made of a nonwoven fabric. The longitudinal direction of the accordion fold pack, transversely to the folds, the individual fold peaks are folded over in the same direction in at least one strip on one or both sides of the accordion fold pack and in each case fixedly joined to the next following, likewise turned-down fold at least in the overlapping region, by heat-sealing.