FILTER ELEMENT AND FILTER SYSTEM

Abstract

A first filter element of a filter system is arranged in a housing, with a second filter element arranged coaxially and concentrically inside the first filter element. The first filter element has a first end disk at a first outlet-side end face and a second end disk at a second oppositely positioned end face. First and second end disks each have a central opening and extend annularly about the respective end face. The second filter element has a first outlet-side end face and a second oppositely positioned end face. The second end face of the second filter element is closed fluid-tightly by a cover. The cover closes the opening in the second end disk of the first filter element fluid-tightly. Between the second end faces of the first and second filter elements, a seal interface is arranged sealing directly the first and second filter elements against each other.

Claims

1. A filter system comprising: a housing comprising an inlet and an outlet for a fluid; a first filter element, comprising a filter medium and embodied as a hollow body, arranged in the housing; a second filter element arranged in an interior of the first filter element, wherein the first filter element and the second filter element are arranged coaxially and concentrically to each other about a longitudinal axis; the first filter element comprising a first end disk arranged at a first end face of the filter medium arranged at the outlet and further comprising a second end disk arranged at a second end face of the filter medium positioned opposite the first end face, wherein the first end disk comprise a first central opening and extends in an annular shape about the first end face, wherein the second end disk comprise a second central opening and extends in an annular shape about the second end face; wherein the second filter element comprises a first end face arranged at the outlet and a second end face positioned opposite the first end face of the second filter element, wherein the second end face of the second filter element is closed fluid-tightly by a cover; wherein the second opening in the second end disk of the first filter element is closed fluid-tightly by the cover; wherein, between the second end face of the first filter element and the second end face of the second filter element, a seal interface is arranged, wherein the seal interface seals directly the first filter element and the second filter element against each other.

2. The filter system according to claim 1, wherein the first filter element comprises a support pipe, wherein the seal interface comprises a seal surface arranged at the support pipe at an end of the support pipe positioned opposite the outlet, wherein the seal interface further comprises at least one seal element arranged at the second filter element, wherein the at least one seal element seals against the seal surface in an axial direction and/or a radial direction in relation to the longitudinal axis.

3. The filter system according to claim 1, further comprising a circumferentially extending projection arranged at the cover and projecting away from an outer end face of the cover in an axial direction in relation to the longitudinal axis away from the cover, wherein the first filter element comprises a support pipe, wherein the seal interface comprises a seal element arranged at the circumferentially extending projection, wherein the seal element seals against the support pipe of the first filter element in a radial direction in relation to the longitudinal axis.

4. The filter system according to claim 1, wherein the first filter element comprises a support pipe, wherein the seal interface comprises a seal element arranged at a circumferentially extending edge of the cover, wherein the seal element seals against the support pipe of the first filter element in a radial direction in relation to the longitudinal axis.

5. The filter system according to claim 1, wherein the first filter element comprises a support pipe comprising a rim projecting inwardly in a radial direction in relation to the longitudinal axis, wherein the seal interface comprises a seal element arranged at the second end face of the second filter element, wherein the seal element seals in an axial direction in relation to the longitudinal axis against the rim of the support pipe of the first filter element.

6. The filter system according to claim 5, wherein the seal element is arranged at the cover and is a seal ring or a seal projection.

7. The filter system according to claim 1, wherein the seal interface comprises a region of the second end disk of the first filter element and further comprises at least one seal surface arranged at the second filter element.

8. The filter system according to claim 7, wherein the second end disk of the first filter element projects inwardly past the filter medium in a radial direction in relation to the longitudinal axis.

9. The filter system according to claim 7, further comprising a circumferentially extending projection arranged at the cover and projecting away from the cover in an axial direction in relation to the longitudinal axis, wherein the circumferentially extending projection comprises a circumferential surface outwardly positioned in a radial direction in relation to the longitudinal axis, wherein the region of the second end disk of the first filter element is arranged at an inner rim of the second end disk of the first filter element, wherein the inner rim seals against the at least one seal surface provided at the circumferential surface of the circumferentially extending projection.

10. The filter system according to claim 9, wherein the housing comprises a housing part comprising a web projecting inwardly in the axial direction, wherein the second end disk of the first filter element comprises a groove, and wherein the web of the housing part engages the groove of the second end disk of the first filter element.

11. The filter system according to claim 7, further comprising a circumferentially extending projection arranged at the cover and projecting away from the cover in an axial direction in relation to the longitudinal axis, wherein the circumferentially extending projection comprises the at least one seal surface, wherein the at least one seal surface is inwardly positioned in a radial direction in relation to the longitudinal axis, wherein the region of the second end disk of the first filter element seals in the radial direction against the at least one seal surface of the circumferentially extending projection, wherein the circumferentially extending projection engages a groove in the second end disk of the first filter element.

12. The filter system according to claim 7, wherein the second end disk of the first filter element comprises a radial protrusion, circumferentially extending within a cross section of the filter medium of the first filter element, wherein the region is arranged at an end face of the radial protrusion, which end face of the radial protrusion faces inwardly in an axial direction in relation to the longitudinal axis, wherein the radial protrusion seals against the at least one seal surface arranged at an end face of the cover.

13. The filter system according to claim 12, wherein the first filter element comprises a support pipe comprising a circumferentially extending rim projecting inwardly in a radial direction in relation to the longitudinal axis and embedded in the radial protrusion.

14. The filter system according to claim 1, wherein the housing comprises a housing part comprising an inwardly curved end face arranged at the second end face of the first filter element.

15. The filter system according to claim 1, wherein the housing comprises a housing part comprising an end face arranged at the second end face of the second filter element, wherein the end face of the housing part comprises an opening which extends at least partially across the second end face of the second filter element.

16. A filter element for a filter system, the filter element comprising: a filter medium formed to a hollow body about a longitudinal axis; a first end disk arranged at a first end face of the filter medium and a second end disk arranged at an oppositely positioned second end face of the filter medium; the first end disk comprising a first central opening and extending in an annular shape about the first end face; the second end disk comprising a second central opening and extending in an annular shape about the second end face; wherein a seal surface of a seal interface or a region of a seal interface is arranged at the second end face configured to be positioned as intended opposite an outlet of the filter system in an installed state of the filter element in the filter system.

17. The filter element according to claim 16, further comprising a support pipe, wherein the filter medium is arranged about the support pipe, and wherein the support pipe comprises the seal surface of the seal interface.

18. The filter element according to claim 17, wherein the support pipe comprises a radially inwardly projecting rim and wherein the seal surface of the seal interface is arranged at the radially inwardly projecting rim.

19. A filter element for a filter system, the filter element comprising: a support pipe; a filter medium arranged as a single layer or many layers on the support pipe; a circumferentially extending socket arranged at a first end face of the filter medium and projecting in an axial direction; a cover arranged at the oppositely positioned second end face of the filter medium; wherein the cover comprises a seal surface or a seal element, which seal surface or seal element, in an installed state of the filter element in the filter system, is configured to form as intended a seal interface together with another filter element.

20. The filter element according to claim 19, wherein the cover comprises a circumferentially extending projection projecting in the axial direction away from the cover, wherein the circumferentially extending projection carries the seal element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] 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 expedient further combinations.

[0043] FIG. 1 shows a filter system according to an embodiment of the invention in a section illustration.

[0044] FIG. 2 shows a detail of a filter system according to an embodiment of the invention in a section illustration with a radial sealing action between first and second filter elements.

[0045] FIG. 3 shows a detail of a filter system according to a further embodiment of the invention in a section illustration with a radial sealing action between first and second filter elements.

[0046] FIG. 4 shows a detail of the filter system in FIG. 1 in a section illustration with an axial sealing action between first and second filter elements.

[0047] FIG. 5 shows a detail of a filter system according to a further embodiment of the invention in a section illustration with a radial sealing action between a second filter element and an end disk of a first filter element.

[0048] FIG. 6 shows a detail of a filter system according to a further embodiment of the invention in a section illustration with a radial sealing action between a first and a second filter element.

[0049] FIG. 7 shows a detail of a filter system according to a further embodiment of the invention in a section illustration with a radial sealing action between a first and a second filter element.

[0050] FIG. 8 shows a detail of a filter system according to a further embodiment of the invention in a section illustration with an axial sealing action between a first and a second filter element.

[0051] FIG. 9 shows a filter system according to a further embodiment in a section illustration.

[0052] FIG. 10 shows a detail of the embodiment according to FIG. 9 in a section illustration.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0053] In the Figures, same or same-type components are identified with same reference characters. The Figures show only examples and are not to be understood as limiting.

[0054] In the embodiments in FIGS. 1 to 4, a seal interface 80 comprises a seal element 60, 62, 64 at the cover 50 of the second filter element 40 and a seal surface 25 at a support pipe 24 of the first filter element 10.

[0055] FIGS. 1 and 4 show a filter system 100 according to a first embodiment of the invention, wherein FIG. 1 is a view of a longitudinal section through the filter system 100 and FIG. 4 a detail of the filter system 100 in FIG. 1. For example, the filter system 100 is an air filter system, in particular an air filter system for an internal combustion engine, preferably an air filter system for an internal combustion engine of a motor vehicle or a cathode air filter of a fuel cell of a motor vehicle.

[0056] The filter system 100 comprises a housing 102 with an inlet 108, which can be arranged, for example, tangentially at the housing 102 and is hidden in the Figure by the housing 102, and a socket-shaped outlet 110 for a fluid which is arranged coaxially to a longitudinal axis 70. Inlet 108 and outlet 110 are arranged, for example, at oppositely positioned axial ends of the housing 102. The housing 102 comprises a first housing part 104, for example, a housing pot, and a second housing part 106, for example, a housing cover. The housing pot can be fixedly mounted and the housing cover can be pulled off from it in order to have access to the housing interior.

[0057] In the housing 102, a first filter element 10 of a hollow cylindrical configuration is arranged coaxially to the longitudinal axis 70. In an interior 30 of the first filter element 10, a second filter element 40 is arranged coaxially to the longitudinal axis 70 and concentrically to the first filter element 10.

[0058] The longitudinal axis of the housing 102 coincides in the illustrated embodiment with the longitudinal axis of the first filter element 10 and of the second filter element 40 so that here only a single common longitudinal axis 70 is referenced. However, embodiments are also conceivable in which the first filter element 10 and the second filter element 40 are arranged concentrically relative to each other about a longitudinal axis which is different from a longitudinal axis of the filter housing. In these cases, the filter elements would be eccentrically arranged in the filter housing.

[0059] The first filter element 10, also referred to as main element 10, comprises a filter medium 11 arranged on a support pipe 24. The first filter element 10 comprises a first end disk 14 arranged at an outlet-side end face 12 and a second end disk 18 arranged at the oppositely positioned end face 16. Both end disks 14, 18 each comprise an opening 21, 22 and extend substantially in an annular shape about the respective end face 12, 16 of the filter medium 11. The filter medium 11 is folded in a zigzag shape, for example. The openings 21, 22 in the illustrated embodiment are arranged coaxially to the longitudinal axis 70.

[0060] The second filter element 40, also referred to as secondary element 40, comprises a filter medium 47 arranged on a support pipe 48. For example, the filter medium 47 is applied as a single layer or many layers on the support pipe 48. The second filter element 40 comprises an outlet-side first end face 42 and a second end face 46 positioned opposite the outlet-side end face 42. The first end face 42 is open and comprises a socket 44 which is connected to the first housing part 104 at the socket-shaped outlet 110, for example, is screwed thereto by means of an outer thread, not identified in detail, at the socket 44 of the second filter element 40.

[0061] The second filter element 40 can serve as a safety element when exchanging the main filter element 10 but can be configured also as harmful gas filter element and adsorb harmful gases. For this purpose, the filter medium 47 can comprise active carbon.

[0062] The flow direction of the fluid between inlet 108 and outlet 110 through both filter elements 10, 40 is indicated by broad arrows. The filter elements 10, 40 are flowed through in radial direction 74 from the exterior to the interior. The first filter element 10 can be pulled out of the housing 102 while the second filter element 40 remains still connected to the second housing part 104 and protects the clean-side outlet 110 from unfiltered fluid.

[0063] The second filter element 40 is fluid-tightly closed by a cover 50 at its second end face 46 which is positioned opposite the clean-side outlet 110. The second filter element 40 closes the opening 22 in the second end disk 18 fluid-tightly by means of the cover 50. For fluid-tight closure of the opening 22, a seal interface 80 is arranged between the second end face 16 of the first filter element 10 and the second end face 46 of the second filter element 40. The cover 50 and the support pipe 48 of the second filter element 40 are preferably embodied together as a single piece.

[0064] At the end face regions of the filter elements 10, 40 positioned opposite the clean-side outlet 110, the seal interface 80 comprises generally at least one seal surface at one of the filter elements 10, 40 and at least one seal element at the other one of the filter elements 10, 40. The second filter element 40 closes the opening 22 in the end disk 18 of the first filter element 10 fluid-tightly without requiring additional components. Depending on the embodiment, the seal element can seal in axial direction 72 or in radial direction 74.

[0065] In the embodiment illustrated in FIG. 1, which is shown enlarged in FIG. 4, the seal interface 80 is provided with an annular seal element 64 at the cover 50 as well as a seal surface 25 at the support pipe 24 of the first filter element 10. The cover 50 and the support pipe 48 of the second filter element 40 are preferably embodied together as one piece. The seal element 64 is arranged at the end face 46 of the second filter element 40 at a circumferentially extending projection 54 of the cover 50 which is projecting outwardly in axial direction 72. The projection 54 is embedded in the seal element 64. The seal element 64 forms a circumferentially extending ring on the cover 50 and seals at the seal surface 25 axially against a rim 26 of the support pipe 24 projecting inwardly in radial direction 74. The rim 26 of the support pipe 24 is resting on the end disk 18.

[0066] In the second housing part 106, a receptacle for the first filter element 10 is provided so that the first filter element 10, in the region of its second end disk 18, contacts with its outer side a ring 116 surrounding the filter element 10. The first filter element 10 is supported by support knobs, not identified in detail, at the bottom of the second housing part 106.

[0067] In the illustrated embodiment, the second housing part 106 is inwardly curved with a depression in the end face 112 in the region of the opening 22 of the end disk 18. The depression projects into the opening 22.

[0068] Since the basic configuration of the filter elements 10, 40 and of the housing 102 is substantially identical in the various embodiments, only significant differences at the seal interface 80 will be explained in the further embodiments in order to avoid unnecessary repetitions.

[0069] FIG. 2 shows a detail of a filter system 100 according to a further embodiment of the invention in a section illustration with a seal interface 80 with a radial sealing action between first and second filter element 10, 40.

[0070] The seal interface 80 comprises a seal element 60 embodied as a seal ring and arranged at a circumferentially extending projection 52 which projects at an outer end face of the cover 50 outwardly in axial direction 72 away from the cover 50 and is embedded in the seal element 60. The seal element 60 seals in radial direction 74 against the seal surface 25 at the support pipe 24 of the first filter element 10. The support pipe 24 comprises a cross-sectional constriction in the region of the seal surface 25 of the first filter element 10.

[0071] The first filter element 10 is received in a receptacle in the second housing part 106 and is surrounded radially outwardly by a ring 116. As before, the bottom of the second housing part 106 comprises a depression in the end face 112 in the region of the opening 22 of the end disk 18 of the first filter element 10.

[0072] FIG. 3 shows a detail of a filter system 100 according to a further embodiment of the invention in a section illustration with a seal interface 80 with a radial sealing action between first and second filter elements 10, 40.

[0073] The seal interface 80 comprises a seal element 62 arranged at an edge 51 of the cover 50 and sealing in radial direction 74 against a support pipe 24 of the first filter element 10. The seal element 62 comprises an L-shaped cross section with a leg projecting in axial direction 72 and a leg projecting inwardly in radial direction 74. The seal element 62 can be molded on or the edge 51 can be framed with a foamed polymer.

[0074] The support pipe 24 comprises a cross-sectional constriction in the region of the seal surface 25 of the first filter element 10.

[0075] The first filter element 10 is received in a receptacle in the second housing part 106 and is surrounded radially outwardly by a ring 116. As before, the bottom of the second housing part 106 comprises a depression in the end face 112 in the region of the opening 22 of the end disk 18 of the first filter element 10.

[0076] In the embodiments in FIGS. 5 to 8, the seal interface 80 comprises a region 15 of the second end disk 18 of the first filter element 10 as seal element and a seal surface 45 at the second filter element 40.

[0077] FIG. 5 shows a detail of a filter system 100 according to a further embodiment of the invention in a section illustration with a radial sealing action between first and second filter elements 10, 40.

[0078] The region 15 is arranged at an inner rim of the second end disk 18 of the first filter element 10 and seals against a seal surface 45 at a circumferential surface, outwardly positioned in radial direction 74, of a circumferentially extending projection 52 arranged at the cover 50 and projecting in axial direction 72 away from the cover 50. A web 114 at the second housing part 106 projecting in axial direction 72 engages a groove 17 of the second end disk 18. In this way, the end disk 18 is supported by the second housing part 106 of the housing 102. In this way, an outer ring 116 (FIGS. 2, 3, 4) arranged radially in relation to the first filter element 10 for receiving the first filter element 10 in the second housing part 106 can be dispensed with.

[0079] In this embodiment, the second housing part 106 in the region of the opening 22 in the second end disk 18 of the first filter element 10 is not curved but is designed open so that the cover 50 can be seen from the exterior.

[0080] FIG. 6 shows a detail of the filter system 100 according to a further embodiment of the invention in a section illustration with a radial sealing action between first and second filter elements 10, 40.

[0081] The region 15 of the second end disk 18 of the first filter element 10 seals in radial direction 74 against a seal surface 45 at an inner side of a circumferentially extending projection 56 arranged at the cover 50. The projection 56 projects in axial direction 72 away from the cover 50 and is arranged at the outer rim of the cover 50. The end disk 18 extends with a radial protrusion 20 past the rim region of the cover 50. The projection 56 engages a groove 19 in the radial protrusion 20 of the end disk 18. The inner circumference of the second end disk 18 of the first filter element 10 is supported in radial direction 74 by a web 118 at the second housing part 106, which web is projecting inwardly in axial direction 72, and is secured in radial direction 74 between the web 118 and the ring 116 in the second housing part 106.

[0082] In this embodiment, the second housing part 106 is also not curved in the region of the opening 22 in the second end disk 18 of the first in filter element 10 but is of an open configuration so that the cover 50 can be seen from the exterior.

[0083] FIG. 7 shows a detail of a filter system 100 according to a further embodiment of the invention in a section illustration with a radial sealing action between first and second filter elements 10, 40. The seal interface 80 comprises a region 15 at the second end disk 18 of the first filter element 10, positioned opposite a clean-side outlet 110 (FIG. 1), and comprises at least one seal surface 45 at the second filter element 40, against which the region 15 of the second end disk 18 of the first filter element 10 is resting seal-tightly.

[0084] The second end disk 18 of the first filter element 10 projects with a radial protrusion 20 in radial direction 74 inwardly past the filter medium 11.

[0085] The region 15 is arranged at an inner rim of the second end disk 18 of the first filter element 10 which seals against a seal surface 45 at a circumferential surface, outwardly positioned in radial direction 74, of a circumferentially extending projection 52 arranged at the cover 50, which projection projects in axial direction 72 outwardly away from the cover 50.

[0086] In this embodiment, the bottom of the second housing part 106 is curved wherein a depression in the end face 112 projects into the opening 22. The filter element 10 is received in a receptacle at the second housing part 106 and is surrounded by a supporting ring 116 in the region of its second end disk 18.

[0087] FIG. 8 shows a detail of a filter system 100 according to a further embodiment of the invention in a section illustration with an axial sealing action between first and second filter elements 10, 40.

[0088] The region 15 is arranged at an end face 58, facing inwardly in axial direction 72, of a radial protrusion 20, circumferentially extending within the cross section of the filter medium 11, of the second end disk 18 of the first filter element 10, which protrusion seals against a seal surface 45 at an end face of the cover 50. The support pipe 24 comprises a rim 23 which projects in radial direction 74 inwardly and which is embedded in the radial protrusion 20 of the second end disk 18 and thereby reinforces it. The second end disk 18 can axially support the seal interface 80 in this region.

[0089] In FIG. 9, a further embodiment of a filter system 100 is illustrated, wherein the inner filter element 40 comprises a filter medium 47 in the form of a folded bellows which is arranged about a support pipe 48. At the end faces, the open folds are fluid-tightly closed by means of an end disk 41, 49, respectively. The end disks 41, 49 are formed preferably of an elastic material, in particular PUR foam. The upper end disk 49 is an open annular end disk and comprises a circumferentially extending seal bead which seals against the socket 110. The bottom end disk 41 is also of an annular configuration and surrounds the cover 50 of the support pipe 48. The support pipe 48 or the cover 50 is embedded in sections in the material of the end disk 41. As an alternative, the end disk 41 can be of a disk-shaped configuration and cover the cavity which is enclosed by the filter element 40 at the end face so that the cover 50 as part of the support pipe 48 can be dispensed with.

[0090] In FIG. 10, a detail of the filter system illustrated in FIG. 9 is illustrated in the region of the seal interface 80 of the bottom-side end disks 18, 41. The two filter elements 10, 40 are sealed axially relative to each other. The support pipe 24 comprises an annular rim 27 which projects inwardly in radial direction 74 and which is embedded in sections in the material of the end disk 18. Radially inwardly, the annular rim 27 comprises a groove 29 which in the radially outward direction is delimited by an annular projection 59. This groove 29 serves for receiving an axially oriented annular seal projection 43 at the bottom end disk 41 of the inner filter element 40. The annular projection 59 of the rim 27 rests axially against the flat axial end face of the end disk 41 of the inner filter element 40. Due to this configuration, a reliable axial sealing action between the two filter elements 10, 40 is ensured. The bottom end disk 41 of the inner filter element 40 forms at the same time the sealing action of the folds and the interface to the outwardly positioned filter element 10; additional sealing elements are not required.

[0091] Advantageously, the inner filter element 40 can be a filter element for harmful gas adsorption. For this purpose, the filter element is correspondingly embodied suitably for adsorption of harmful gases. Preferably, the filter medium contains active carbon.

[0092] Of course, also further seal configurations for sealing two filter elements 10, 40 embodied as folded bellows are possible. For example, a radially outer section of the bottom end disk 41 of the inner filter element 40 can seal against a rim of the support pipe 24 of the outer filter element 10, which rim projects in axial direction, for embodying a radial sealing action, similar to the embodiment of FIG. 2 or FIG. 3.