Filter element having a filter bellows

1. A filter element for fluids, comprising:

a filter bellows made of a sheet of filter medium, the filter medium sheet folded in into zig-zag pleats, each pleat having:

a first pleat fold edge arranged on a prefiltration surface of the filter bellows; and

an opposite second pleat fold edge arranged on an opposite post filtration surface of the filter bellows;

each pleat having:

a first pleat end edge extending from the first pleat fold edge on the prefiltration surface, to the opposite second pleat fold edge arranged on the post filtration surface;

a second pleat end edge extending from the first pleat fold edge on the prefiltration surface, to the opposite second pleat fold edge arranged on the post filtration surface, the first and second pleat end edges arranged at opposites ends of the pleat fold edges of the pleat;

wherein the first pleat end edges of the pleats form a first end surface extending from the prefiltration surface to the opposite post filtration surface of the filter bellows on the first pleat end edges;

wherein the second pleat end edges of the pleats form an opposing second end surface of the filter bellows, extending from the prefiltration surface to the opposite post filtration surface of the filter bellows on the second pleat end edges;

wherein a first group of side-by-side pleats have the first pleat end edges extending obliquely to the first fold edge or to the second fold edge such that, the first group of side-by-side pleats have the first pleat end edge on the first end surface of the filter bellows that has a different length relative to a length of the second pleat end edge on the second end surface of the filter bellows;

wherein the pleat end edges of adjacent pleats are directly sealed onto each other by at least one trace of a sealant in the form of a support glue bead between the pleat end edges of adjacent pleats;

wherein the first group of side-by-side pleats at the first end surface of the filter bellows has first pleat end edges running oblique to the second pleat end edges of the first group of side-by-side pleats such that the first end surface twists or deflects along it length from end to end, such that the prefiltation surface at the second portion of pleats has a different pleat fold edge length than a pleat fold edge length of same respective pleats at the post filtration surface of the filter bellows.

2. The filter element according to claim 1 , wherein

at least one segment of one of the end edges of the pleats runs obliquely to a direction in which the pleat fold edges follow one another.

3. The filter element according to claim 1 , wherein

a circumferential seal made of polyurethane foam, that has been foamed onto the filter bellows is provided circumferentially on the pleated bellows.

4. The filter element according to claim 1 , wherein

there are provided at least one first element segment; and

at least one second element segment;

wherein the at least one first element segment and the at least one second element segment each have end edge segments running parallel to one another on opposite end faces;

wherein the at least one first element segment has end edges running perpendicular to the pleated edges; and

wherein the at least one second other element segment has at least one beveled end edge.

5. The filter element according to claim 4 , wherein

the second element segment having the beveled end edge has shorter pleated edges than the at least one first element segment.

6. The filter element according to claim 1 , wherein

one or more segments of the at least one segment of one of the end edges that run obliquely to at least one of the pleated edges have an outer shape having at least one change of direction.

7. The filter element according to claim 6 , wherein the first end surface of the filter bellows has a wave-shaped margin.

8. The filter element according to claim 1 , wherein

a housing component of a filter housing protrudes out into an empty space created by the obliquely extending at least one segment of one of the end edges in an installed state of the filter element into the filter housing, so as to produce a clearly defined installation space with a flat filter element.

9. The filter element according to claim 1 , wherein

the filter bellows is assembled into a circular element.

10. The filter element according to claim 9 , wherein

the circular element is cylindrical in shape at one axial end, and has an end plate that extends substantially perpendicular to a longitudinal axis of the circular element, and

wherein the circular element is beveled at an opposite axial end.

11. The filter element according to claim 10 , wherein

at the beveled axial end of the circular element, a circumferential seal is provided;

wherein the seal is comprised of polyurethane foam, that has been foamed onto the filter bellows;

wherein the seal has an opening through which the interior of the circular element is accessible.

12. A filter system comprising

a filter element according to claim 1 ;

a filter housing in which the filter element is replaceably arranged.