FLEXIBLE AIR FILTER ELEMENT

Abstract

The invention refers to a deformable filter element comprising a flexible side element to seal pleats of its filter medium. An end section of the side element is bent over fold edges. The end section and the fold edges are secured to one another. The end section and a main section of the side element, which main section is typically arranged perpendicular to the fold edges, are neither parallel nor perpendicular to each other.

Claims

1. Filter element comprising a pleated filter medium and at least a first flexible side element, in particular a first flexible sideband, which seals pleats of the filter medium at a first side face, wherein at least a first end section of the first side element protrudes above first fold edges of the filter medium, wherein the first end section is angled towards the filter medium with respect to a main section of the first side element by an angle of at least 5? and at most 85? and, wherein the first end section is affixed to the first fold edges.

2. Filter element according to claim 1, wherein the angle between the first end section and the main section is at least 22?, preferably at least 35?, and/or at most 67?, preferably at most 55?.

3. Filter element according to claim 1, wherein the first side element is made from a nonwoven fabric.

4. Filter element according to claim 1, wherein the first side element is glued to the filter medium and the first end section of the first side element is at least partly glued to the first fold edges, in particular wherein a glue layer provided between an end face of the first side element and the first fold edges has a thickness that is larger than the glue layer provided between a first edge of the first fold edges and an intersection of the main section and the first end section.

5. Filter element according to claim 1, wherein the filter medium comprises at least two layers of filter media and filling material, in particular particulate filling material, arranged between the layers.

6. Filter element according to claim 5, wherein the filling material comprises adsorbent material, in particular activated carbon, ion exchange resin and combinations thereof.

7. Filter element according to claim 1, wherein an end face of the first side element extends approximately perpendicular, preferably at an angle of 90?+/?30?, particularly preferably at an angle of 90?+/?15?, with respect to the first end section.

8. Filter element according to claim 1, further comprising a second flexible side element, in particular a second flexible sideband, which seals pleats of the filter medium at a second side face, wherein at least a first end section of the second side element protrudes above the first fold edges of the filter medium, wherein the first end section of the second side element is angled towards the filter medium with respect to a main section of the second side element by an angle of at least 5? and at most 85?, and wherein the first end section of the second side element is affixed to the first fold edges.

9. Filter element according to claim 1, wherein a second end section of the first side element, or of the second side element if present, protrudes above second fold edges of the filter medium, wherein the second end section is angled towards the filter medium with respect to a main section of the first side element by an angle of at least 5? and at most 85?, and wherein the second end section is affixed to the second fold edges.

10. Filter element according to claim 1, wherein, in an undeformed state, the filter element is plate-shaped.

11. Filter element according to claim 1, wherein the filter medium annularly surrounds a longitudinal axis.

12. Air filter comprising a housing and a filter element according to claim 1.

13. Air filter according to claim 12, wherein the filter element is installed in the housing in an undeformed state.

14. Air filter according to claim 12, wherein the filter element is installed in the housing in a deformed state, in particular wherein the filter element is bent around an axis parallel to its fold edges and/or twisted around an axis perpendicular to its fold edges.

15. Air filter according to one of claim 12, wherein an outer edge of the filter element, which is formed between the first end section and an end face of the first side element, sealingly abuts the housing.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0032] Other advantages and features of the invention will be appreciated from the following description of embodiments of the invention with reference to the figures of the drawing, which show significant details, and from the claims. The individual features, as described above or explained below, may each be implemented individually or implemented together in any useful combination in variants of the invention.

[0033] FIG. 1 shows a first embodiment of a filter element according to the invention, in a schematic perspective view;

[0034] FIG. 2 shows a schematic cross section of a pleated filter medium of the filter element of FIG. 1;

[0035] FIG. 3 shows a detail of the filter element of FIG. 1 in the area of a first sideband, in a schematic view;

[0036] FIG. 4 shows a second embodiment of a filter element according to the invention in a bent state, in a schematic perspective view;

[0037] FIG. 5 shows an air filter according to the invention comprising a housing and the filter element of FIG. 4, in a schematic perspective view;

[0038] FIG. 6 shows the air filter of FIG. 5 in a schematic sectional view;

[0039] FIG. 7 shows a detail of the air filter of FIG. 5 during installation, in a schematic sectional view;

[0040] FIG. 8 shows a detail of FIG. 6;

[0041] FIG. 9 shows a second air filter according to the invention, in a schematic perspective view;

[0042] FIG. 10 shows a detail of the air filter of FIG. 9 during installation of a filter element, in a schematic sectional view;

[0043] FIG. 11 shows a detail of FIG. 9, in a sectional view;

[0044] FIG. 12 shows a third air filter according to the invention, during installation of a filter element into a housing, in a schematic perspective view;

[0045] FIG. 13 shows a detail of sealing between a filter element and a housing of the air filter of FIG. 12, in a schematic sectional view;

[0046] FIG. 14 shows a fourth air filter according to the invention, during installation of a filter element into a housing, in a schematic perspective view;

DETAILED DESCRIPTION

[0047] FIG. 1 shows a filter element 10. The filter element comprises a pleated filter medium 12. First and second fold edges (or pleat tips) 14, 16 define an upstream and downstream face 18, 20, respectively, see also FIG. 2. The fold edges 14, 16 run parallel to each other. In an undeformed state, which is depicted in FIG. 1, the filter element is plate-shaped; the upstream and downstream face 18, 20 are flat.

[0048] As can be seen from FIG. 2, the filter medium 12 comprises two layers of filter paper 22. A filling material 24, in this embodiment activated carbon particles, is enclosed between the layers of filter paper 22.

[0049] The filter element 10 comprises a first and a second side element 26, 28, here first and second sidebands, which seal the pleats of the filter medium 12 at a first and second side face 30, 32, respectively, see FIG. 1. A first edge 17 of the fold edges 14, 16 is at the first side face 30. The first edge 17 contacts the intersection of a main section 34 and a first end section 36 of the first side element 26. The first edge 17 also contacts the intersection of the main section 34 and a second end section 68 of the first side element 26 if present. A second edge 19 of the fold edges 14, 16 is at the second side face 32. The second edge 19 contacts the intersection of a main section 34 and a first end section 36 of the second side element 28. The second edge 19 also contacts the intersection of the main section 34 and a second end section 68 of the second side element 28 if present.

[0050] The side elements 26, 28 are made from flexible material, such as a nonwoven fabric. The side elements 26, 28 are adhered to the filter medium 12 by a hotmelt adhesive. Alternatively, the side elements 26, 28 may be made from a flexible thermoplastic material, such as rubber or hotmelt material, which may melt during production and adhere to the filter medium 12 when hardened.

[0051] A main section 34 of the side elements 26, 28 extends in a plane, which is perpendicular to the fold edges 14, 16, at least in the undeformed or flat state of the filter element 10. As is apparent in particular from FIG. 3, the side elements 26, 28 protrude beyond the first fold edges 14. In particular, the first side element 26 bends along the first edge 17, while the second side element 28 bends along the second edge 19. A first end section 36 of the first and second side elements 26, 28 is bent towards the filter medium 12. An angle 37 between outer surfaces of the main section 34 and the first end section 36 is preferably about 45?, for instance 45?+/?5?. In particular, the first end sections 36 cover the first fold edges 14 adjacent to the first or second side face 30, 32, respectively. The first end sections 36 are secured to the first fold edges 14, here by means of the hotmelt adhesive. It may be provided that the first fold edges 14 are impressed into the side elements 26, 28. Due to the inclined angle of the first end sections 36, the thickness of adhesive between the edges 17, 19 and the intersection of the main section 34 and first end section 36 is smaller than the thickness of adhesive between the fold edges 14, 16 and an end face 38 of the side element 26, 28.

[0052] At the first end section 36, the first and second side element 26, 28 each terminate in an end face 38. The end face 38 is oriented approximately perpendicular (for instance 90?+/?10?) to the outer surface of the first end section 36 (angle 35).

[0053] FIG. 4 shows a filter element 10 in a bent state. In particular, the filter element 10 is bent around an axis 39, which runs parallel to fold edges 14, 16.

[0054] The filter element 10 depicted in FIG. 4 differs from the filter element 10 shown in FIG. 1 in that only the first side element 26 has an angled end section 36; here, the second side element 28 is flat overall. In the bent configuration, the first end section 36 is on the radially outer side of filter element 10 with respect to bending axis 39.

[0055] In the bent shape, the filter element 10 may be inserted into a filter housing 42 to form an air filter 40, see FIGS. 5 and 6. A cover of housing 42 is not depicted. The first and second side elements 26, 28 sealingly abut the housing 42. An inlet and an outlet of the housing 42 for raw air and filtered air, respectively, are not depicted in FIGS. 5 and 6.

[0056] As can be appreciated in particular from FIG. 5 and FIG. 7, the housing 42 comprises two housing parts 44, 46. At a joint between the housing parts 44, 46 a protrusion 48 into the interior of the housing is formed. During installation of the filter element 10, the inclination of the first end section 36 facilitates pushing the first side element 26 past the protrusion 48. During removal of the filter element 10, the inclination of the end face 38 facilitates pulling the first side element 26 over the protrusion 48.

[0057] In the installed state, an outer edge 50, which delimits the outer surface of the first end section 36 from the end face 38, sealingly abuts an inner surface 51 of the housing 42, see in particular FIG. 8. In FIGS. 7 and 8, the outer edge 50 is shown in an undeformed configuration to overlap with the housing 40. Actually, the first side element 26 is compressed at the outer edge 50; the resulting contact pressure creates the desired sealing effect.

[0058] FIG. 9 shows an air filter 52 comprising a housing 54 and a filter element 10, as depicted in FIG. 1 and described above. The housing 54 comprises two housing parts 56, 58. At a joint between the housing parts 56, 58 a protrusion 48 into the interior of the housing is formed, see FIG. 10.

[0059] With the air filter 52, the filter element 10 is arranged inside the housing 54 in the undeformed, flat state.

[0060] For insertion into the housing 54, the filter element 10 may be bent and/or twisted. If enough space above housing 54 is available, the filter element 10 may be pushed into housing 54 in its undeformed, plate-like configuration. Then, the insertion direction is basically perpendicular to the upstream or downstream face 18, 20.

[0061] During installation of the filter element 10, the inclination of the first end section 36 facilitates pushing the first side element 26 past the protrusion 48. Since the filter element 10 is installed in its flat configuration, outer edge 50 sealingly abuts a flat sealing surface 60 of housing 54, see FIG. 11.

[0062] FIG. 12 shows an air filter 62 comprising a cuboid housing 64, a cover of which is not depicted. Likewise an inlet and an outlet are not depicted in detail. The housing 64 is designed for insertion of a flat filter element 10 in a direction 66 perpendicular to its upstream and downstream face 18, 20.

[0063] In the embodiment of FIG. 12, the filter element 10 does not only comprise first end sections 36, which are angled towards the filter medium 12, as described above for the filter element 10 depicted in FIG. 1. Here, the side elements 26, 28 do also protrude beyond the second fold edges 16 at the downstream face 20, see also FIG. 13. Second end sections 68 of the side elements 26, 28 are bent inwards to cover the second fold edges 16 adjacent to the first or second side face 30, 32, respectively. The second end sections 68 are designed in the same way as the first end sections 36. In particular, the second end sections 68 are adhered to the second fold edges 16.

[0064] Both, the first and second end sections 36, 68 of the first and second side elements 26, 28 sealingly abut housing 64, see FIG. 13. During installation, contact of adhesive, which is applied between filter medium 12 and side elements 26, 28, and the housing 64 is avoided, since the end sections 36, 68 cover the outer portions of fold edges 14, 16.

[0065] FIG. 14 shows an air filter 70 similar to the air filter 62 of FIG. 12; in particular the same filter element 10 is used in FIGS. 12 and 14. Air filter 70 differs from air filter 62 in that its housing 72 is curved along insertion direction 66. Consequently, the filter element 10 is bent during installation and remains bent or flat, depending on the remaining configuration of housing 72 n the completely installed state (not depicted in detail). Here, a bending axis 39 is parallel to the fold edges 14, 16 of filter medium 12. Sealing contact between filter element 10 and housing 72 is established as depicted in FIG. 13 and described above.

[0066] In summary, the invention refers to a deformable filter element comprising a flexible side element to seal pleats of its filter medium. An end section of the side element is bent over fold edges. The end section and the fold edges are secured to one another. The end section and a main section of the side element, which main section is typically arranged perpendicular to the fold edges, are neither parallel nor perpendicular to each other.

LIST OF REFERENCE SIGNS

[0067] Filter element 10 [0068] Filter medium 12 [0069] First fold edges 14 [0070] Second fold edges 16 [0071] First edge 17 [0072] Upstream face 18 [0073] Second edge 19 [0074] Downstream face 20 [0075] Filter paper 22 [0076] Filling material 24 [0077] First side element 26 [0078] Second side element 28 [0079] First side face 30 [0080] Second side face 32 [0081] Main section 34 [0082] Angle 35 [0083] First end section 36 [0084] Angle 37 [0085] End face 38 [0086] Axis 39 [0087] Air filter 40; 52; 62; 70 [0088] Housing 42; 54; 64; 72 [0089] Housing parts 44, 46; 56, 58 [0090] Protrusion 48 [0091] Outer edge 50 [0092] Inner surface 51 [0093] Sealing surface 60 [0094] Insertion direction 66 [0095] Second end section 68