Filter element
A filter element ( 1 ) has an inner body ( 12 ) and an outer body ( 11 ). One casing body ( 12 ) has a cross section deviating from circularity. Body contact surfaces ( 20, 21 ) face one another for the contact of essentially all filter folds ( 18 a - 18 f, 18 I - 18 III ) of a pleated filter web ( 10 ). The filter folds ( 18 a - 18 f, 18 I - 18 III ), in terms of fold height (h), are divided into individual groups (I, II) each having several filter folds ( 18 I - 18 II ) of a common fold height (h max , h min ) alongside one another in sections. Between two adjacent filter folds ( 18 a - 18 f, 18 I - 18 III ) of different groups (I, II) filter folds are arranged ( 18 b - 18 e; 18 m ) of at least one third group (III). The filter folds ( 18 b - 18 e, 18 m ) of the third group (III), in the manner of step formation, have a common fold height (h D ) different from the respective fold height (h max , h min ) of the filter folds ( 18 I - 18 II ) of the two adjacent neighboring groups (I, II), and/or, in the manner of curve formation, have different fold heights, establishing a transition between the fold heights (h max , h min ) of the two adjacent groups (I, II).
1. A filter element, comprising:
at least one inner jacket body and at least one outer jacket body with inner and outer contact faces, respectively, at least one of said jacket bodies deviating from a circular shape and the other of said jacket bodies substantially conforming to a circular shape; and
a pleated filter web consisting essentially of filter folds divided at least first, second and third individual groups of a plurality of said filter folds arranged alongside each other in sections, said filter folds contacting the respective contact faces, each of said filter folds having a fold height, each of said filter folds in each of said first and second groups having a common or equal fold height in the respective individual group, said filter folds of said third individual group being arranged between two adjacent filter folds of said first and second individual groups, each of said filter folds of said third individual group in a step formation having a common or equal fold height different from the respective fold heights of the filter folds of adjacent adjoining first and second individual groups.
2. A filter element according to claim 1 wherein
the fold height of each of said filter folds of said third individual group produces a transition between the fold heights of the adjacent adjoining first and second individual groups.
3. A filter element according to claim 2 wherein
said transition has a wave or sine shape.
4. A filter element according to claim 1 wherein
adjacently juxtaposed filter folds of said first individual group each have a first fold height;
adjacently juxtaposed filter folds of said second individual group each have a second fold height and are arranged in an alternating sequence with said first individual group along said filter web, said first and second fold heights being different; and
between the adjacently juxtaposed filter folds of said first and second individual groups, adjacently juxtaposed filter folds of said third individual groups are arranged.
5. A filter element according to claim 4 wherein
said third fold height is an average of said first and second fold heights.
6. A filter element according to claim 1 wherein
numbers of the filter folds of each of said first and third individual groups are equal.
7. A filter element according to claim 1 wherein
the filter folds follow a periodic course of first, second and third individual groups along said filter web, with each period having 15 to 20 filter folds.
8. A filter element according to claim 1 wherein
said inner jacket body has a cross-sectional shape of a convex polygon.
9. A filter element according to claim 8 wherein
said convex polygon is a Reuleaux polygon.
10. A filter element according to claim 1 wherein
said outer jacket body has a cross-sectional shape of a convex polygon.
11. A filter element according to claim 10 wherein
said convex polygon is a Reuleaux polygon.
12. A filter element according to claim 1 wherein
each filter fold has a cross-sectional configuration of at least one of a zigzag, a wave and a sickle.
13. A filter element according to claim 1 wherein
said filter web is closed and has filter web ends connected in a connecting region.
14. A filter element according to claim 1 wherein
said outer jacket body has a circular shape in cross section; and
said inner jacket body has a non-circular shape in cross section.
15. A filter element according to claim 1 wherein
said filter folds have inner and outer peaks substantially evenly spaced on said inner and outer contact faces, respectively.