FILTER ELEMENT AND FILTER DEVICE

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.

Claims

1. A filter element comprising: a filter medium comprising 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; wherein a fold height of the successive folds continuously decreases in the longitudinal direction; and wherein a fold width of the successive folds continuously decreases in the longitudinal direction.

2. The filter element according to claim 1, wherein the fold width of the successive folds decreases segmentally in the longitudinal direction.

3. The filter element according to claim 2, wherein the fold height of the successive folds decreases segmentally in the longitudinal direction.

4. The filter element according to claim 1, wherein the fold height of the successive folds decreases segmentally in the longitudinal direction.

5. The filter element according to claim 1, wherein the fold height of the successive folds decreases steadily in the longitudinal direction at least in regions of the filter medium.

6. The filter element according to claim 5, wherein the fold height of the successive folds decreases steadily continuously from the first transverse side to the second transverse side.

7. The filter element according to claim 1, wherein first fold edges of the successive folds extend in a first plane.

8. The filter element according to claim 7, wherein second fold edges of the successive folds extend in a second plane.

9. The filter element according to claim 8, wherein the first fold edges and the second fold edges extend parallel to each other.

10. The filter element according to claim 8, wherein the second fold edges extend parallel to each other.

11. The filter element according to claim 7, wherein the first fold edges extend parallel to each other.

12. The filter element according to claim 1, wherein a fold division of the successive folds amounts to 3.7 mm to 6 mm when the fold height amounts to 400 mm to 500 mm.

13. The filter element according to claim 1, wherein a fold division of the successive folds amounts to 3.3 mm to 4.5 mm when the fold height amounts to 275 mm to 400 mm.

14. The filter element according to claim 1, wherein a fold division of the successive folds amounts to 3.0 mm to 3.7 mm when the fold height amounts to 175 mm to 275 mm.

15. The filter element according to claim 1, wherein a fold division of the successive folds amounts to 2.5 mm to 3.3 mm when the fold height amounts to 75 mm to 175 mm.

16. The filter element according to claim 1, wherein a fold division of the successive folds amounts to 5.0 mm to 10.0 mm when the fold height amounts to 400 mm to 500 mm.

17. The filter element according to claim 1, wherein a fold division of the successive folds amounts to 4.0 mm to 8.0 mm when the fold height amounts to 275 mm to 400 mm.

18. The filter element according to claim 1, wherein a fold division of the successive folds amounts to 4.0 mm to 6.1 mm when the fold height amounts to 175 mm to 275 mm.

19. The filter element according to claim 1, wherein a fold division of the successive folds amounts to 3.5 mm to 5.0 mm when the fold height amounts to 75 mm to 175 mm.

20. A filter device comprising a filter housing and a filter element according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Further features and advantages of the invention result from the following detailed description of embodiments of the invention, from the claims as well as with the aid of the Figures of the drawing showing details according to the invention. The aforementioned and still further explained features can be realized individually by themselves or several in arbitrary expedient combinations in variants of the invention. The features shown in the drawing are illustrated in such a way that the particularities according to the invention can be made clearly visible.

[0036] FIG. 1 shows a filter element according to the invention in which in a longitudinal direction a height of folds of a filter medium decreases steadily and a width of the folds decreases segmentally, in a schematic cross section view.

[0037] FIG. 2 shows a filter element according to the invention in which in a longitudinal direction a height and a width of folds of a filter medium decrease steadily, in a schematic cross section view.

[0038] FIG. 3 shows a filter device according to the invention with a filter element according to the invention arranged in a filter housing, in a schematic cross section view.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0039] FIG. 1 shows a filter element 10. The filter element 10 comprises a folded filter medium 12. The filter medium 12 can be held in a frame of the filter element 10, not illustrated in detail, wherein the frame can carry a circumferentially extending seal or can be itself embodied as such. The filter element 10 is configured as a so-called flat filter element, i.e., it extends between a raw side and an oppositely positioned clean side without enclosing an intermediately positioned hollow space that can be flowed through. The filter element 10 is substantially rectangular but in principle can have any other cross section shape.

[0040] The filter medium 12 comprises a plurality of folds 14. The folds 14 are arranged successively in a longitudinal direction 16. The folds 14 are delimited, on the one hand (in FIG. 1 at the bottom), by first fold edges 18. On the other hand (in FIG. 1 at the top), the folds 14 are delimited by second fold edges 20. Neighboring folds 14 adjoin each other at the second fold edges 20. Here, the first fold edges 18 extend all in a first plane 22. The second fold edges 20 can also extend all in a second plane 24. The first and the second fold edges 18, 20 can extend respectively parallel to each other and in particular perpendicularly to the longitudinal direction 16. In FIG. 1, the fold edges 18, 20 extend perpendicularly to the drawing plane. The filter medium 12 extends in the longitudinal direction 16 from a first transverse side 26 to a second transverse side 28.

[0041] The folds 14 of the filter medium 12 each have a different height 30. The height 30 can be measured as the (average) distance of the first fold edges 18 from the second fold edges 20 of a respective fold 14 perpendicularly to the longitudinal direction and perpendicularly to the fold edges 18, 20. The height 30 of every fold 14 arranged closer to the second transverse side 28 is here smaller than a height 30 of every fold 14 arranged closer to the first transverse side 26. Folds 14 arranged closer to the first transverse side 26 have thus a larger height 30 than folds 14 arranged closer to the second transverse side 28. In other words, the height 30 of the folds 14 continuously decreases steadily in the longitudinal direction 16 from the first transverse side 26 to the second transverse side 28.

[0042] The folds 14 of the filter medium 12 have different widths 32a, 32b, 32c. The filter medium 12 comprises here a plurality of segments 34a, 34b, 34c in which the widths 32a, 32b, 32c of the folds 14 are of the same size, respectively. In other words, all folds 14 of one of the segments 34a, 34b, 34c each have the same width 32a, 32b or 32c. The folds 14 of a segment 34a, 34b arranged closer to the first transverse side 26 comprise a larger width 32a, 32b than the folds 14 of the segments 34b, 34c arranged closer to the second transverse side 28. In other words, the width 32a, 32b, 32c of the folds 14 decreases segmentally in the longitudinal direction 16. In this way, the width 32a, 32b, 32c of the folds 14 decreases from the first transverse side 26 continuously to the second transverse side 28.

[0043] Example 1: For an air filter element for filtration of intake air for an internal combustion engine with a media permeability of 80 l/m2/s to 250 l/m2/s and a filtration speed of 2 cm/s-8 cm/s, the following values have been found to be particularly advantageous:

[0044] Advantageously, the fold height in the first segment 34a decreases from approximately 500 mm to approximately 400 mm and the fold division amounts to a constant value between 3.7 mm and 6.0 mm, for example, 4.5 mm. In the second segment 34b, the fold height decreases from 400 mm to 275 mm and the fold division amounts to 3.3 mm to 4.5 mm, for example, 3.7 mm. In the third segment 34c, the fold height lies between 275 mm and 175 mm for a fold division between 3.0 mm and 3.7 mm, for example, 3.3 mm.

[0045] The third segment 34c can be adjoined by a fourth segment—not illustrated—in which the fold heights from approximately 175 mm on decrease, preferably to a height of approximately 75 mm, and which has a fold division between 2.5 mm and 3.3 mm.

[0046] Example 2: For an air filter element for HVAC applications with a media permeability of 25 l/m2/s and a filtration speed of 1 cm/s-3 cm/s, the fold division in the first segment 34a lies between 5.0 mm and 10.0 mm, for example, at 6 mm, in the second segment 34b between 4.0 mm and 8.0 mm, and in the third segment 34c between 4.0 mm and 6.0 mm, while the fold height, as in the first embodiment, in the first segment 34a lies between 400 mm and 500 mm, in the second segment 34b between 275 mm and 400 mm, and in the third segment 34c between 275 mm and 175 mm. In a fourth segment, not illustrated, with a fold height between 75 mm and 175 mm, the fold division amounts to 3.5 mm to 5.0 mm.

[0047] FIG. 2 shows a further filter element 40. The filter element 40 is constructed similarly to the filter element 10 of FIG. 1. In the following, primarily the differences are described. In other respects, reference is being had to the prior description.

[0048] In the filter element 40—as in the filter element 10 of FIG. 1—a height 30 of folds 14 of a filter medium 12 continuously decreases steadily in a longitudinal direction 16. From a first transverse side 26 to a second transverse side 28, the height 30 of the folds 14 decreases continuously.

[0049] In contrast to the filter element 10 of FIG. 1, it is provided in the filter element 40 illustrated in FIG. 2 that a width 32 of the folds 14 along the longitudinal direction 16 decreases steadily. The width 32 of each fold 14 arranged closer to the second transverse side 28 is in this context smaller than a width 32 of each fold 14 arranged closer to the first transverse side 26. Folds 14 arranged closer to the first transverse side 26 have thus a greater width 32 than folds 14 arranged closer to the second transverse side 28. In this way, the width 32 of the folds 14 decreases continuously from the first transverse side 26 to the second transverse side 28. In this context, a ratio of the respective height 30 and of the respective width 32 can have the same value for each one of the folds 14.

[0050] FIG. 3 shows a filter device 50. The filter device 50 is embodied here as an air filter. The filter device 50 can be used for filtering combustion air for an internal combustion engine, for filtering cathode air for a fuel cell or as an interior air filter in a motor vehicle.

[0051] The filter device 50 comprises a filter housing 52. In the filter housing 52, a filter element is arranged, for example, the filter element 10 of FIG. 1 or the filter element 40 of FIG. 2. The filter element 10/40 separates in the filter housing 52 a raw side 54 from a clean side 56. A circumferentially extending frame 57 of the filter element 10/40 can seal the filter medium 12 in relation to the filter housing 52. The raw side 54 communicates with an inflow opening 58. The clean side 56 communicates with an outflow opening 60. In operation of the filter device 50, air to be filtered flows through the inflow opening 58 into the raw side 54. The air passes then through the filter element 10/40, wherein dirt particles are retained in the filter medium 12, so that filtered air reaches the clean side 56. From the clean side 56, the filtered air flows through the outflow opening 60 out of the filter housing 52.

[0052] In summarizing, the invention concerns a filter element with a folded filter medium. The filter element can be a flat filter element. A height and a width (division) of folds of the filter medium is variable. In a length direction, the height as well as the width of the folds can decrease continuously. Folds with a larger width have a greater height than folds with a smaller width.

LIST OF REFERENCE CHARACTERS

[0053] filter element 10, 40 [0054] filter medium 12 [0055] folds 14 [0056] longitudinal direction 16 [0057] first fold edges 18 [0058] second fold edges 20 [0059] first plane 22 [0060] second plane 24 [0061] first transverse side 26 [0062] second transverse side 28 [0063] height 30 of the folds 14 [0064] width 32, 32a, 32b, 32c of the folds 14 [0065] segments 34a, 34b, 34c [0066] filter device 50 [0067] filter housing 52 [0068] raw side 54 [0069] clean side 56 [0070] frame 57 [0071] inflow opening 58 [0072] outflow opening 60