Abstract: A filter element has a filter medium with a plurality of successive folds arranged in a longitudinal direction from a first transverse side of the filter medium to a second transverse side of the filter medium. A fold height of the successive folds continuously decreases in the longitudinal direction. A fold width of the successive folds continuously decreases in the longitudinal direction. A filter device such as an air filter is provided with such a filter element.

Abstract: A device for producing a bellows from a filter medium, including: an embossing device embossing fold lines into a filter medium that runs through the embossing device, producing an embossed filter medium for folding into a folded filter medium; the folded section of the filter medium being delimited by two adjacent fold lines; an adhesive application device applying adhesive onto the embossed filter medium; and a folding device folding, in a zig-zag manner, the embossed filter medium onto which the adhesive was applied into the folded filter medium; wherein the folding device includes a plurality of adjacent supporting elements that can be moved into or out of a folding space of the folding device; wherein the supporting elements are movable into the folding space such, that at least one folded section of the folded filter medium is contacted and supported by a respective one of the plurality of supporting element.

Abstract: A device for producing a bellows from a filter medium, including: an embossing device embossing fold lines into a filter medium that runs through the embossing device, producing an embossed filter medium for folding into a folded filter medium; the folded section of the filter medium being delimited by two adjacent fold lines; an adhesive application device applying adhesive onto the embossed filter medium; and a folding device folding, in a zig-zag manner, the embossed filter medium onto which the adhesive was applied into the folded filter medium; wherein the folding device includes a plurality of adjacent supporting elements that can be moved into or out of a folding space of the folding device; wherein the supporting elements are movable into the folding space such, that at least one folded section of the folded filter medium is contacted and supported by a respective one of the plurality of supporting element.