Filter Element with Filter Bellows

Abstract

A filter element for filtering a fluid is provided with a filter bellows made of a filter medium folded along fold edges in a zigzag shape to form folds, wherein the folds extend between oppositely positioned end face edges of the filter bellows. The filter bellows defines a raw side and a clean side of the filter element, wherein a fluid to be filtered flows from the raw side to the clean side. The filter medium has faces that are flowed through by the fluid to be filtered. The filter medium is provided at least on one of the faces that are flowed through with beads extending transversely to the fold edges. In a proper operating state of the filter bellows, the beads effect a flow of at least a portion of the fluid to be filtered in a direction perpendicular to the fold edges.

Claims

1. A filter element for filtering a fluid, the filter element comprising: a filter bellows comprising a filter medium folded along fold edges in a zigzag shape to form folds, wherein the folds extend between oppositely positioned end face edges of the filter bellows; wherein the filter bellows defines a raw side and a clean side of the filter element, wherein a fluid to be filtered flows from the raw side to the clean side; wherein the filter medium comprises faces that are flowed through by the fluid to be filtered and wherein the filter medium further comprises on at least one of the faces that are flowed through one or more beads extending transversely to the fold edges of the filter medium; wherein, in a proper operating state of the filter bellows, the beads effect a flow of at least a portion of the fluid to be filtered in a direction perpendicular to the fold edges.

2. The filter element according to claim 1, wherein, in the folded state of the filter medium, the folds each comprise oppositely positioned fold edge surfaces and the beads cause the oppositely positioned fold edge surfaces of the folds to be spaced apart, respectively, at least in the operating state of the filter element.

3. The filter element according to claim 1, wherein the beads cross the fold edges at crossing points, wherein at least at some of the crossing points the beads have a tapered portion.

4. The filter element according to claim 3, wherein the tapered portion is a portion of reduced height.

5. The filter element according to claim 3, wherein the tapered portion is an embossed portion.

6. The filter element according to claim 3, wherein the beads are interrupted at least at some of the crossing points.

7. The filter element according to claim 1, wherein the beads are arranged on a designated clean side of the filter medium forming the clean side of the filter element.

8. The filter element according to claim 1, wherein the beads are hot melt beads applied onto the filter medium.

9. The filter element according to claim 1, wherein the filter bellows is of a hollow cylindrical form and the filter medium is folded in a star shape.

10. The filter element according to claim 1 in the form of a round filter element for filtering a fluid.

11. The filter element according to claim 1 in the form of a round filter element of an internal combustion engine.

12. A method for producing a filter element according to claim 1, comprising: unwinding the filter medium from a roll; applying beads onto the filter medium; embossing fold edges into the filter medium; erecting the fold edges to form a zigzag-shaped folded filter bellows.

13. The method according to claim 12, further comprising pressing on the beads.

14. The method according to claim 12, further comprising heating the filter medium prior to embossing the fold edges in the filter medium and embossing the heated filter medium.

15. The method according to claim 12, wherein the step of applying beads is carried out prior to embossing.

16. The method according to claim 12, wherein the step of applying beads is carried out after embossing.

17. An apparatus for manufacturing a filter element according to claim 1, comprising at least the following devices for manufacturing a filter bellows: an unwinding device; a polymer application device; a feed heating device; an embossing device; a fold erecting device.

18. The apparatus according to claim 16, further comprising a pressing roller.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Further advantages result from the following drawing description. In the drawings embodiments of the invention are illustrated. The drawings, the description, and the claims contain numerous features in combination. A person of skill in the art will consider the features expediently also individually and combine them to other meaningful combinations.

[0037] FIG. 1 shows an isometric illustration of a filter element according to an embodiment of the invention.

[0038] FIG. 2 shows a partial cross-section of a filter element according to an embodiment of the invention.

[0039] FIG. 3 is a plan view of a filter medium according to an embodiment of the invention.

[0040] FIG. 4 is a schematic illustration of an apparatus for manufacturing a filter element according to an embodiment of the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0041] In the Figures, same or similar components are identified with same reference characters. The Figures show only examples and are not to be understood as limiting.

[0042] FIG. 1 shows an isometric illustration of a filter element 10 according to an embodiment of the invention. The filter element 10 for filtering a fluid comprises a filter bellows 12 of a filter medium 14 which is folded along fold edges 26 in a zigzag shape to folds 34 which extend between opposite end face edges 22a, 22b of the filter bellows 12, respectively. The filter medium 14 is designed for flow of the fluid from a raw side 50 of the filter element to a clean side 52 and particularly in a flow direction 54 from an exterior surface to an inner area of the filter element 10. On several of its flow-through faces, the filter medium 14 comprises several beads 42 on the clean side 52 (shown in FIGS. 2 and 3) which extend transverse to the fold edges 26 of the filter medium 14 and which, in the proper operating state of the filter bellows 12, effect flow of at least a portion of the fluid in a direction perpendicular to the fold edges 26 of the folds 34 of the filter bellows 12. Alternatively, the beads 42, or at least some of the beads 42, can also be extending in a wavy configuration and/or zigzag shape (indicated in FIG. 3). The filter element 10 in FIG. 1 is formed as a hollow cylindrical round filter element with a star-shaped folded filter medium 14. Such round filter elements are used in the automotive field preferably as air, oil, or fuel filters or the like and are employed on the internal combustion engines as exchangeable filter elements 10 with regular exchange intervals. The filter bellows 12 is closed at both end faces with terminal discs 16, 18 which comprise a central tube 38 through which the filtered fluid can flow out in flow direction 54.

[0043] In FIG. 2 a partial section view of a filter element 10 according to an embodiment of the invention, as shown in FIG. 1, is illustrated. The cross-section shows several folds 34 of the filter bellows 12 which are folded to a round shape at fold edges 26. The fluid to be filtered passes from the raw side 50 outside of the round filter 10 into an inner area of the filter element 10 with the clean side 52. The filter bellows 12 is reinforced in the inner area with a central tube 38 that is partially illustrated in section. The filter medium 14 has beads 42 at the clean side 52. In addition to the drainage action for discharging the filtered fluid, the beads 42 cause the oppositely positioned fold edge surfaces 20a, 20b of a fold 34 of the filter bellows 12 in the folded state of the filter medium 14 to be spaced apart at least in the operating state. The beads 42 are arranged in particular on the fold edge surfaces 20a, 20b and not in the curvature area of the folds 34.

[0044] FIG. 3 shows a plan view of a filter medium 14 according to an embodiment of the invention. The flat filter medium 14 has regularly spaced fold edges 26 which can be formed by embossing the filter medium 14. Beads 42 are extending transverse thereto. The beads 42 can be formed, for example, by application of a hot melt. At crossing points with the fold edges 26, the beads 42 have tapered portions 44, in particular a reduced height. The tapered portions 44 can also be embodied as embossments of the fold edges 26 inasmuch as the beads 42 are applied prior to embossment of the filter medium 14. Alternatively, the beads 42 can be interrupted at crossing points with the fold edges 26. This can be affected in that the hot melt application is interrupted when being applied at the crossing points, respectively.

[0045] In an alternative variant, the beads 42 can also be extending in a wavy shape and/or zigzag shape. In FIG. 3 a bead 50 with such a course is indicated as an example. Such a course of the beads 42 is advantageous in that the bead sections will contact each other reliably at oppositely positioned fold edge surface sections 20a, 20b in the folded filter medium 14.

[0046] In FIG. 4, a schematic illustration of an apparatus 100 for manufacturing a filter element 10 according to an embodiment of the invention is shown. The method for manufacturing a filter element 10 according to the invention comprises the following manufacturing steps of the filter bellows 12: unwinding the filter medium 14 from a roll, storing the filter medium 14 in a material store 104, applying beads 42 onto the filter medium 14 prior to or after embossment for forming fold edges 34, pressing on the beads 42, erecting the fold edges 34 to a zigzag-shaped folded filter bellows 12. Such a process can be integrated conveniently into the usual manufacturing sequence for manufacturing a filter bellows 12 in which the filter medium 14 is usually passing through an embossing device 110 in the form of long webs. Accordingly, additional adhesive application stations 106 can be provided that additionally apply the hot melt at the same speed so that the normal manufacturing process is not impaired. Interruptions of the applied beads 42 can thus be provided also conveniently in that the adhesive application stations 106 are appropriately controlled and provided with valves.

[0047] The application of the beads 42 can be provided prior to or after an embossment process. When the beads 42 are applied prior to embossment, they can be provided during the embossment process with desired tapered portions 44 at the crossing points with the fold edges 26 in order to promote erection of the fold edges 26 to folds 34, in particular to pointedly extending folds. Alternatively, the beads 42 can however also be applied after the embossment process. In this context, the tapered portions 44 can be realized by interruptions of the beads 42, for example, by application of hot melt beads with interruption at the fold edges 26.

[0048] The beads 42, after having been applied onto the filter medium 14, can advantageously be pressed onto the filter medium 14 in order to achieve a good and permanent adhesion. This can be conveniently effected by a rolling process, for example.

[0049] Expediently, the method for manufacturing a filter element 10 can comprises additional manufacturing steps of a filter bellows 12 such as heating the filter medium as a preparation for embossment, embossing fold edges 26 into the filter medium 14. Embossing fold edges 26 into the filter medium 14 can be beneficially realized by prior heating of the filter medium 14 because the embossed fold edges 26 are thus maintained permanently.

[0050] The apparatus 100 for manufacturing a filter medium 10 in FIG. 4 comprises the following devices for manufacturing a filter bellows 12: an unwinding device 102, a material store 104, a polymer application station 106 for applying the beads 42, a pressing roller 107 for pressing on the beads 42 onto the filter medium 14, a feed heating device 108, an embossing device 110, as well as a fold erecting device 112. Instead of the polymer application station 106, a hot melt application station can be provided also when a hot melt bead is to be employed as a bead 42.

[0051] While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.