Filter Assembly

Abstract

A filter assembly has a main filter element disposed in a filter housing and provided with an end disk with a first sealing element that seals the main filter element relative to the filter housing. A secondary filter element is disposed in the filter housing and is provided with an end disk with a second sealing element that seals the secondary filter element relative to the filter housing. The end disk of the secondary filter element is arranged relative to an axial direction of the filter assembly between the end disk of the main filter element and the filter housing. The end disk of the secondary filter element is arranged inside a flow cross section of a fluid outlet of the filter housing. The end disks of the main filter element and of the secondary filter element are axially supported on each other at least over sections thereof.

Claims

1. A filter assembly comprising: a filter housing; a main filter element disposed in the filter housing and comprising an end disk with a first sealing element that seals the main filter element relative to the filter housing; a secondary filter element disposed in the filter housing and comprising an end disk with a second sealing element that seals the secondary filter element relative to the filter housing; wherein the end disk of the secondary filter element is arranged relative to an axial direction of the filter assembly between the end disk of the main filter element and a support structure of the filter housing; wherein the end disk of the secondary filter element is arranged inside a flow cross section of a fluid outlet of the filter housing; wherein the end disk of the main filter element and the end disk of the secondary filter element are supported on each other at least over sections thereof in the axial direction.

2. The filter assembly according to claim 1, wherein the first sealing element seals the main filter element radially relative to the filter housing in a first sealing direction and wherein the second sealing element seals the secondary filter element radially relative to the filter housing in a second sealing direction.

3. The filter assembly according to claim 2, wherein the first sealing direction of the first sealing element is oriented opposite to the second sealing direction of the second sealing element.

4. The filter assembly according to claim 1, wherein the support structure of the filter housing comprises a plurality of support ribs and wherein the end disk of the secondary filter element is arranged between the end disk of the main filter element and the support ribs.

5. The filter assembly according to claim 4, wherein the support ribs project radially into the flow cross section of the fluid outlet of the filter housing.

6. The filter assembly according to claim 1, wherein the end disk of the main filter element comprises a first circumferentially extending rib that is supported on the end disk of the secondary filter element.

7. The filter assembly according to claim 6, wherein the first circumferentially extending rib has breaks.

8. The filter assembly according to claim 1, wherein the end disk of the secondary filter element comprises a second circumferentially extending rib that is supported on the end disk of the main filter element.

9. The filter assembly according to claim 8, wherein the second circumferentially extending rib has breaks.

10. The filter assembly according to claim 1, wherein the end disk of the main filter element comprises a first circumferentially extending rib and the end disk of the secondary filter element comprises a second circumferentially extending rib, wherein the first circumferentially extending rib is supported directly on the second circumferentially extending rib.

11. The filter assembly according to claim 10, wherein the first circumferentially extending rib or the second circumferentially extending rib has breaks.

12. The filter assembly according to claim 10, wherein the first circumferentially extending rib and the second circumferentially extending rib have breaks.

13. The filter assembly according to claim 1, wherein the secondary filter element is arranged outside of an interior of the main filter element.

14. The filter assembly according to claim 1, wherein the second sealing element is arranged inside the first sealing element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG. 1 shows a schematic perspective exploded view of an embodiment of a filter assembly.

[0026] FIG. 2 shows a schematic section view of the filter assembly according to FIG. 1.

[0027] FIG. 3 shows a further schematic section view of the filter assembly according to FIG. 1.

[0028] FIG. 4 shows a schematic perspective partial section view of the filter assembly according to FIG. 1.

[0029] FIG. 5 shows a schematic section view of a further embodiment of a filter assembly.

[0030] FIG. 6 shows a further schematic section view of the filter assembly according to FIG. 5.

[0031] FIG. 7 shows a schematic section view of a further embodiment of a filter assembly.

[0032] In the Figures, same or functionally the same elements, unless otherwise specified, are provided with the same reference characters.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0033] FIG. 1 shows a schematic perspective exploded view of an embodiment of a filter assembly 1. FIG. 2 shows a schematic section view of the filter assembly 1. FIG. 3 shows a further schematic section view of the filter assembly 1 and FIG. 4 shows a schematic perspective partial section view of the filter assembly 1. In the following, reference is being had simultaneously to FIGS. 1 through 4.

[0034] The filter assembly 1 comprises a filter housing 2. The filter housing 2 comprises a first cover 3 with an inflow socket 4, a second cover 5 with an outflow socket 6, a filter receptacle 7 arranged between the first cover 3 and the second cover 5, and an intermediate element 8 that is arranged between the filter receptacle 7 and the second cover 5. The filter receptacle 7 comprises an oval geometry in cross section. The first cover 3, the filter receptacle 7, the intermediate element 8, and the second cover 5 are detachably connected to each other by means of quick release clamps 9 of which a plurality are provided. In particular, on the first cover 4 as well as on the filter receptacle 7, a plurality of quick release clamps 9 are provided, respectively. Filter receptacle 7 and intermediate element 8 can also be embodied together as one piece. Moreover, the second cover 5 and the filter receptacle 7 and/or the intermediate element 8 can be embodied together as one piece.

[0035] The filter assembly 1 comprises moreover a main filter element or first filter element 10 and a secondary filter element or second filter element 11 that are both received together in the filter housing 2. The first filter element 10 can also be referred to as primary filter element, primary element or main element. The second filter element 11 can be referred to also as safety filter element, safety element, secondary element, auxiliary element, or auxiliary filter element.

[0036] The filter assembly 1 can be used preferably in motor vehicles, trucks, construction vehicles, watercraft, rail vehicles, agricultural machines or vehicles, or aircraft. The second cover 5 is then connected with a fluid line. The filter assembly 1 or the first filter element 10 is in particular suited to filter combustion air of an internal combustion engine. Preferably, the first filter element 10 is an air filter. The second filter element 11 can also be suitable for filtering combustion air of an internal combustion engine. Preferably, the second filter element 11 is also an air filter. The second filter element 11 is optional. This means that the filter assembly 1 can function even without the second filter element 11. The second cover 5 is preferably connected with a supply line for purified combustion air of the internal combustion engine or partially forms it.

[0037] The first filter element 10 comprises a filter medium 12 that surrounds a support tube or center tube 13. For example, the filter medium 12 can be wound onto the center tube 13. The center tube 13 is preferably of a grid structure and thus fluid-permeable. In particular, the center tube 13 can be made from plastic material. The filter medium 12 is preferably folded. The filter medium 12 is, for example, a filter fabric, a laid filter material, or a filter nonwoven. In particular, the filter medium 12 can be produced by spun-bonding or melt-blowing methods. Moreover, the filter element 12 can be felted or needled. The filter medium 12 can comprise natural fibers, such as cellulose or cotton, or synthetic fibers, for example, of polyester, polyvinylsulfite or polytetrafluoroethylene. The fibers can be oriented during processing in the machine direction, at a slant thereto and/or transverse thereto.

[0038] The first filter element 10 comprises a first end disk 14 and a second end disk 15 between which the filter medium 12 is arranged. The end disks 14, 15 are preferably manufactured from plastic material. The end disks 14, 15 can be made, for example, from PUR, in particular from a foamed PUR. The end disks 14, 15 can be cast onto the filter medium 12 and onto the center tube 13 so that the filter medium 12 and the center tube 13 at least partially extend into the end disks 14, 15. The end disks 14, 15 are at least over sections thereof resiliently deformable and/or compressible. The end disks 14, 15 and also the entire filter elements 10, 11 are formed mirror-symmetrical to a symmetry plane E.

[0039] The second end disk 15 comprises in this embodiment a centrally arranged receiving section 16 into which an engagement section 17 of the first cover 3 engages with form fit. The engagement section 17 can be a tubular plug with a central passage 18. The receiving section 16 of the second end disk 15 seals relative to the engagement section 17 in axial direction, i.e., in a longitudinal direction LR of the filter assembly 1, as well as radially, i.e., perpendicular to the longitudinal direction LR so that no fluid can exit from the filter housing 2 through the central passage 18. The engagement section 17 is part of a receiving collar 19 of the first cover 3.

[0040] The second end disk 15 comprises moreover a plurality of regularly spaced apart spacers 20 that are designed to be supported on corresponding support sections 21 of the first cover 3. By means of the receiving collar 19, of the spacers 20, and of the support sections 21, the first filter element 10 is positioned in such a way in the filter housing 2 that it cannot move relative to the filter housing 2 even in case of strong vibrations.

[0041] It is self-evident that the axial support of the first filter element 10 in the housing 2 is also possible in ways different from the illustrated way.

[0042] The first filter element 10 comprises a resiliently deformable first sealing element 22 that is provided on a front face 23 of the first end disk 14 which is facing away from the filter medium 12. The first sealing element 22 is in particular monolithically formed together with the first end disk 14 and extends in an annular shape about the first end disk 14. The first sealing element 22 comprises an oval geometry or contour. The first sealing element 22 is configured to seal the first filter element 10 radially relative to the filter housing 2. For this purpose, the filter housing 2 in the area of the intermediate element 8 has a circumferentially extending receiving section 24 in which the first sealing element 22 is received. In axial direction or in longitudinal direction LR, a stop 25 projects into the receiving section 24 by means of which the first filter element 10 can be positioned axially in the filter housing 2.

[0043] The filter housing 2 or the intermediate element 8 comprises moreover a tubular sealing section 26, oval in cross section, against which the first sealing element 22 radially seals in a first sealing direction R.sub.1. The first sealing direction R.sub.1 is perpendicular to the longitudinal direction LR and is oriented away from the first sealing element 22 in the direction toward the second filter element 11. The first sealing element 22 is resiliently deformed or compressed upon sealing relative to the sealing section 26. This deformation of the first sealing element 22 is indicated in FIGS. 2 through 4 by overlap of the first sealing element 22 and the sealing section 26.

[0044] Moreover, a first circumferentially extending rib 27 is provided on the front face 23 of the first end disk 14. The first circumferentially extending rib 27 extends inside the first sealing element 22 and is spaced at a constant spacing circumferentially relative to the first sealing element 22. The first circumferentially extending rib 27 has no sealing action and can be provided with breaks, perforations, or cutouts so that the first circumferentially extending rib 27 is not fluid-tight.

[0045] The filter housing 2 or the intermediate element 8 comprises moreover a fluid outlet 28 with a flow cross section A.sub.28. The flow cross section A.sub.28 can have an oval geometry. The flow cross section A.sub.28 is partially visible in perspective in FIG. 4 and is provided with cross hatching for clarification purposes. A plurality of support ribs 29 are projecting radially into the flow cross section A.sub.28. Beginning at the sealing section 26, the support ribs 29 extend radially into the flow cross section A.sub.28. The number of support ribs 29 is random. Preferably, the support ribs 29 are arranged to be uniformly spaced from each other.

[0046] The first filter element 10 comprises in longitudinal direction LR an oval or elliptical cross section. The cross section can decrease beginning at the first end disk 14 in the direction of the second end disk 15 so that the first filter element 10 tapers conically. Alternatively, the first filter element 10 can be cylindrical and can have an oval or elliptical base surface. In the present case, “oval” can be understood as a rectangular cross section with rounded corners, an elliptical cross section, or a cross section formed of a plurality of circular arcs. The cross section is symmetrically configured.

[0047] The second filter element 11 is at least partially received in an interior 30 of the first filter element 10. The interior 30 is delimited in this context by the center tube 13. The second filter element 11 comprises a filter medium 31 which is preferably not folded and is thus flat. The filter medium 31 is, for example, a filter fabric, a laid filter material, or a filter nonwoven. In particular, the filter medium 31 can be produced by a spun-bonding method or melt-blowing method. Moreover, the filter medium 31 can be felted or needled. The filter medium 31 may comprise natural fibers, such as cellulose or cotton, or synthetic fibers, for example, of polyester, polyvinylsulfite, or polytetrafluoroethylene. The fibers can be oriented during processing in the machine direction, at a slant thereto and/or transverse thereto.

[0048] The second filter element 11, as can be seen clearly in FIG. 1, is of a bag-shaped configuration. The filter medium 31 is attached to a support tube or center tube 32. The center tube 32 delimits an interior 33 of the second filter element 11. The center tube 32 is grid-shaped and fluid-permeable. For example, the center tube 32 is an injection-molded plastic part. The second filter element 11 comprises only one end disk 34 which is preferably made from plastic material. The end disk 34 can be made from PUR, in particular from foamed PUR. The end disk 34 is resiliently deformable and compressible.

[0049] The end disk 34 can be cast onto the center tube 32 and onto the filter medium 31 so that they are fixedly connected with the end disk 34. The end disk 34 comprises a front face 35 facing the support ribs 29 and a back face 36 facing away from the support ribs 29. The support ribs 29 are contacting the front face 35. The end disk 34 is thus arranged between the support ribs 29 as a support structure of the filter housing 2 and the first end disk 14 of the first filter element 10. In this way, clamping of the end disk 34 between the filter housing 2 and the first end disk 14 of the first filter element 10 can be achieved.

[0050] The end disk 34 comprises a circumferentially extending second sealing element 37 for radial sealing of the second filter element 11 relative to the filter housing 2. In particular, the second sealing element 37 is monolithically formed together with the end disk 34. The second sealing element 37 seals in a second sealing direction R.sub.2, oriented opposite to the first sealing direction R.sub.1, relative to the sealing section 26 of the intermediate element 8 or the filter housing 2. In this context, the second sealing element 37 is compressed. This elastic deformation of the second sealing element 37 is shown in FIGS. 2 to 4 by an overlap of the second sealing element 37 and of the sealing section 26. Like the first sealing element 22, the second sealing element 37 comprises an oval geometry or contour in the viewing direction in the longitudinal direction LR. The second sealing element 37 is arranged inside the first sealing element 22 and preferably is spaced apart therefrom at a constant spacing in the circumferential direction.

[0051] On the back face 36 of the end disk 34, a second circumferentially extending rib 38, corresponding to the first circumferentially extending rib 27, is provided. As is shown in FIGS. 2 to 4, the circumferentially extending ribs 27, 38 can be resting against each other so that the end disk 34 of the second filter element 11 is supported on the first end disk 14 of the first filter element 10. The second circumferentially extending rib 38 can also be interrupted. This means it can have breaks, perforations, or cutouts. In particular, the second circumferentially extending rib 38 can be fluid-permeable. First circumferentially extending rib 27 and second circumferentially extending rib 38 are optional, respectively; a direct support of the end disks 14, 34 is also possible. In contrast to the first end disk 14 of the first filter element 10, the end disk 34 of the second filter element 11 is arranged completely inside the flow cross section A.sub.28.

[0052] In operation of the filter assembly 1, the fluid L to be purified, for example, air, flows into the inflow socket 4 of the filter housing 2, is freed from the contaminants by means of the filter elements 10, 11 in the filter housing 2, and flows subsequently out again through the outflow socket 6 of the filter housing 2 as a purified fluid L. In particular, the fluid L to be purified flows from a raw side RO of the first filter element 10 through the filter medium 12 into the interior 30 surrounded by the center tube 13 to a clean side RL of the first filter element 10 as filtered fluid L. The fluid L which has been purified by the first filter element 10 flows then from the interior 30 of the first filter element 10 through the filter element 31 of the second filter element 11 into the interior 33 of the second filter element 11 and from there through the fluid outlet 28 toward the outflow socket 6.

[0053] The functionality of the filter assembly 1 is ensured even without the second filter element 11. The second filter element 11 prevents however upon exchange of the first filter element 10 that fluid L to be filtered can reach unfiltered the fluid outlet 28. Since the end disk 34 of the second filter element 11 is completely arranged inside the flow cross section A.sub.28 of the fluid outlet 28, it is avoided that the flow cross section A.sub.28 is constricted when the second filter element 11 is eliminated. In this way, an increased filter performance can be achieved. In order to avoid a constriction of the flow cross section A.sub.28, the end disk 34 of the second filter element 11 is not arranged between a circumferentially extending step of the filter housing 2 constricting the flow cross section A.sub.28 and the first end disk 14 of the first filter element 10 but between the support ribs 29 that are projecting into the flow cross section A.sub.28 and the first end disk 14 of the first filter element 10.

[0054] FIGS. 5 and 6 show in schematic section views a further embodiment of a filter assembly 1. The filter assembly 1 according to FIGS. 5 and 6 differs from the filter assembly 1 according to FIGS. 1 through 4 only by a different configuration of the second filter element 11. The second filter element 11 is plate-shaped and comprises a folded filter medium 31 with an end disk 34. The second filter element 11 is arranged completely outside of the interior 30 of the first filter element 10 and in particular arranged in the flow cross section A.sub.28 of the fluid outlet 28. The end disk 34 can be cast directly onto the filter medium 31.

[0055] The second filter element 11 may comprise a support frame 39 which is preferably made from a plastic material. The end disk 34 is cast onto the support frame 39 and onto the filter medium 31. The support frame 39 can also be adhesively connected to the filter medium 31. The functionality of the filter assembly 1 according to FIGS. 5 and 6 corresponds to the functionality of the filter assembly 1 according to FIGS. 1 through 4.

[0056] FIG. 7 shows a schematic section illustration of a further embodiment of the filter assembly 1. The filter assembly 1 according to FIG. 7 differs from the filter assembly 1 according to FIGS. 5 and 6 only in that the second filter element 11 comprises no support frame 39. This means that the end disk 34 is directly cast onto the folded filter medium 31.

[0057] 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.

Employed Reference Characters

[0058] 1 filter assembly [0059] 2 filter housing [0060] 3 cover [0061] 4 inflow socket [0062] 5 cover [0063] 6 outflow socket [0064] 7 filter receptacle [0065] 8 intermediate element [0066] 9 quick release clamp [0067] 10 filter element [0068] 11 filter element [0069] 12 filter medium [0070] 13 center tube [0071] 14 end disk [0072] 15 end disk [0073] 16 receiving section [0074] 17 engagement section [0075] 18 passage [0076] 19 receiving collar [0077] 20 spacer [0078] 21 support section [0079] 22 sealing element [0080] 23 front face [0081] 24 receiving section [0082] 25 stop [0083] 26 sealing section [0084] 27 rib [0085] 28 fluid outlet [0086] 29 support rib [0087] 30 interior [0088] 31 filter medium [0089] 32 center tube [0090] 33 interior [0091] 34 end disk [0092] 35 front face [0093] 36 back face [0094] 37 sealing element [0095] 38 rib [0096] 39 support frame [0097] A.sub.28 flow cross section [0098] E symmetry plane [0099] L fluid [0100] LR longitudinal direction [0101] RL clean side [0102] RO raw side [0103] R.sub.1 sealing direction [0104] R.sub.2 sealing direction