Filter element having two filter medium bodies arranged one inside the other

Abstract

The invention relates to a two-stage filter element having an inner and an outer filter medium body, which are able to be flowed through in series. The inner filter medium body is arranged in an interior space of the outer filter medium body. At least one of the filter medium bodies has a folded filter medium, preferably containing activated charcoal, the end side of which is covered by a side band. The side band is embedded continuously, at least in a radial subregion and in the circumferential direction, in an end plate which seals off the other filter medium body at its end side. The end plate may also seal off the folded filter medium body with the side band, wherein the side band may be embedded entirely in the end plate. The side band may have slots in the region embedded in the end plate.

Description

[0001] Filter element with two filter medium bodies arranged one inside the other

[0002] This patent application claims priority from German patent application 102023124179.6, filed with the German Patent and Trademark Office on September 7, 2023, the contents of which are hereby incorporated by reference.

[0003] Technical area

[0004] The invention relates to a filter element having a first and a second annular filter medium body, wherein one of the filter medium bodies is arranged within the other filter medium body and wherein the two filter medium bodies can be flowed through one after the other, wherein the filter element has an end plate on one end face, and wherein at least the second filter medium body has a folded filter medium.

[0005] State of the art

[0006] Such a filter element is known from WO 2015 / 092681 A1.

[0007] In various applications, it may be necessary to pass a fluid to be filtered, especially a gas, sequentially through two different filter media to remove all interfering components from the fluid. For a space-saving design, two annular filter media bodies can be used, with one of the filter media bodies located inside the other.

[0008] Adsorbent filter media are known for retaining harmful gases. For example, activated carbon can be contained in the filter medium. Such a filter medium can, in particular, contain activated carbon particles enclosed between two layers of filter paper. When processing such filter media, for example, there is a risk that activated carbon particles will escape from the open edges of the filter medium. Even when using such filter media, care must be taken to ensure that no activated carbon particles reach the clean side. Furthermore, such filter media have comparatively low inherent rigidity, which complicates handling during production and assembly.

[0009] For serial flow through two filter medium bodies, they must be sealed against each other or a filter housing in an appropriate manner.

[0010] The aforementioned WO 2015 / 092681 A1 describes a filter element with two layers of filter material made of folded paper, which has a cylindrical shape. The two layers of filter material are permanently held together by being embedded in plastic seals in certain areas. The seals can be arranged in the manner of end plates on both end faces of the filter element. It is an object of the invention to provide a filter element with two filter medium bodies sealed against each other and capable of flowing through serially, which can be efficiently manufactured and easily assembled, in particular while preventing the escape of adsorbing particles during the manufacture of the filter element and its operation.

[0011] Disclosure of the invention

[0012] This object is achieved by a filter element according to claim 1, a use of a filter element according to claim 18, and a fuel cell with a filter element according to claim 19. Preferred embodiments are specified in the respective subclaims and the description.

[0013] According to the invention, a filter element is provided with a first and a second annular filter medium body. The filter element is, in particular, a gas filter element. Typically, both filter medium bodies enclose an interior space in the circumferential direction. One of the filter medium bodies is arranged within the other filter medium body. The one (inner) filter medium body is thus accommodated in the interior space of the other (outer) filter medium body. Flow can pass through the two filter medium bodies one after the other.

[0014] The filter element can be round or oval in cross-section; this applies accordingly to the two filter medium bodies. In principle, the two filter medium bodies together surround a longitudinal axis of the filter element, which extends through the interior of the inner and thus also the interior of the outer filter medium body. The longitudinal axis can be an axis of symmetry of the filter element or lie in a plane of symmetry of the filter element. However, the filter element is not necessarily symmetrical with respect to an axis or plane. For the description of the present invention, directional terms such as radial or axial refer to the longitudinal axis, unless otherwise stated.

[0015] Typically, the second filter medium body is permeable to flow after the first filter medium body. The filter element is permeable to flow in a radial direction from the inside out or from the outside in.

[0016] The filter element has a (first) end plate on a (first, axial) end face. The end plate helps seal the two filter elements against each other. In addition, the end plate can seal the first filter medium body at the end face. The first filter medium body can be embedded in the end plate. The end plate can consist of or comprise a sprayable or pourable material. In particular, the end plate can consist of or comprise polyurethane foam. The end plate can be closed. Alternatively, the end plate can have a central opening through which fluid to be filtered can flow into the interior of the filter element or filtered fluid can flow out of the interior. In embodiments, the side band can be at least partially embedded in a sprayable or pourable material of the end plate. The first filter medium body can comprise a folded filter medium.The first filter medium body is preferably made of a filter medium for particle filtration. The first filter medium body can be made of cellulose-containing or synthetic filter paper.

[0017] The second filter medium body comprises a pleated filter medium. The second filter medium body may contain an adsorption medium. The pleated filter medium of the second filter medium body may contain, for example, activated carbon. In particular, activated carbon particles may be enclosed between two layers of filter paper. Such filter media are particularly effective at retaining harmful gases.

[0018] According to the invention, the front edges of the pleated filter medium of the second filter medium body are sealed at the (first) front side by a (first) side band. The side band is typically permanently bonded to the filter medium, so it cannot be removed from the filter medium of the second filter medium body without causing damage. In particular, the side band can be glued to the second filter medium body at the front edges. The side band is generally made of a material whose gas permeability is lower than that of the filter medium of the pleated filter medium body. Depending on the installation situation, however, a higher gas permeability of the side band is also possible.

[0019] In some embodiments, the sideband may extend in a plane extending perpendicular to the longitudinal axis. In some embodiments, the sideband may have a thickness that is several times smaller, in particular at least five times smaller, than the radial extension of the sideband.

[0020] The sideband serves, on the one hand, to guide the flow through the second filter medium body by preventing a gas flow from bypassing the second filter medium body unfiltered. On the other hand, the sideband simplifies handling of the second filter medium body after it has been connected to it. For this purpose, the sideband can stiffen the second filter medium body. This particularly simplifies attaching the two filter medium bodies to each other. Furthermore, the sideband prevents activated carbon particles from escaping from a filter medium containing activated carbon.

[0021] The sideband can have greater flexural rigidity than the filter medium of the second filter medium body. This stabilizes the second filter medium body particularly effectively.

[0022] The sideband may comprise a nonwoven material, in particular a filter nonwoven, a woven fabric, in particular a filter fabric, or a mesh, in particular a filter grid. These materials are available inexpensively and have suitable properties.

[0023] In some embodiments, the side band can comprise an air-permeable material, in particular a nonwoven material. The air permeability of the nonwoven material of the side band can in particular be lower than the air permeability of the filter medium of the filter medium body. Furthermore, according to the invention, the side band is at least partially embedded in the end plate. This, on the one hand, holds the two filter medium bodies together. This creates an easy-to-handle filter element that combines the two filter medium bodies. On the other hand, the two filter medium bodies are sealed against each other by the embedding of the side band in the end plate. For this purpose, the side band is generally embedded in the end plate in a ring-shaped manner. Sealing the two filter medium bodies against each other at the end face can also simplify the sealing of the filter element against a housing, particularly if the end plate is an open end plate.Preferably, the end plate and the side band are arranged at essentially the same axial height. This reduces the material required for embedding.

[0024] The side band can protrude radially beyond the pleated filter medium of the second filter medium body. In particular, the side band can protrude inward and / or outward. The protrusion of the side band can simplify its embedding in the end plate and contribute to further reducing the material required for the end plate.

[0025] In an advantageous embodiment, only a (first) radial portion of the side band is embedded in the end plate. In particular, the side band can be embedded in the end plate only in the radially protruding portion. In the remaining (second) radial portion, the surface of the side band—facing away from the pleated filter medium body—is exposed. This design requires particularly little material to manufacture the end plate. The term "radial portion" refers, in particular, to a circumferential edge on an inner and / or outer circumference of the side band.

[0026] In an alternative embodiment, the side band is completely embedded in the end plate. This can be advantageous with regard to sealing the filter element against a housing. Even if the side band has slots to facilitate the production of the ring shape, complete embedding can be advantageous for flow guidance reasons.

[0027] The second filter medium body with the side band can be arranged radially inside the first filter medium body. In other words, the first filter medium body can surround the second filter medium body with the side band on the outside. In this arrangement, the flow through the filter element typically occurs from the radial outside to the radial inside.

[0028] Alternatively, the second filter medium body with the side band can surround the first filter medium body on the outside. In other words, the first filter medium body can be arranged inside the second filter medium body with the side band. In this arrangement, the flow through the filter element typically occurs from the radial inside to the radial outside.

[0029] The second filter medium body can have at least one folded filter bellows whose head sides are sealed by headbands, the ring shape of the second filter medium body being obtained by gluing two headbands together. This simplifies the manufacture of the second filter medium body. First, the (second) filter medium is folded in a zigzag shape to form a substantially rectangular filter bellows. Its head sides (parallel to the folding direction and in the depth direction of the folds) are provided with the headbands, for example by gluing them on. The filter bellows is then bent and fixed in the ring shape by gluing adjacent headbands together. The sideband is also typically attached before the filter bellows is bent into the ring shape.

[0030] In particular, the second filter medium body can be composed of at least two filter bellows, wherein circumferentially adjacent filter bellows are glued together at their respective headbands. The second filter medium body is thus composed of several filter bellows, wherein the ring-shaped adjacent filter bellows are each fixed to one another and sealed by gluing their headbands. This allows for efficient production of large filter elements.

[0031] The filter element can taper in the axial direction. This can simplify the attachment of a support body to the filter element. In particular, the filter element can be conical.

[0032] The sideband can have slits that extend into folds of the second filter medium body. The slits facilitate the formation of the second filter medium body into the ring shape. The slits can originate from an outer edge or an inner edge of the sideband. The slits generally do not completely penetrate the sideband between the inner and outer edges, but typically extend no more than four-fifths, preferably no more than three-quarters, of the width of the sideband.

[0033] It can be provided that, at least in a partial region comprising at least five, preferably at least ten, consecutive folds open on a common circumferential side, particularly preferably over the entire circumference, of the second filter medium body, a slit, in particular exactly one slit, extends into each fold of the partial region open on the common circumferential side. In this way, the flexibility of the side band can be particularly effectively increased, particularly locally.

[0034] The filter element can have a second end plate on a second (axial) end face, wherein end edges of the second filter medium body are sealed at the second end face by a second side band, and wherein the second side band is at least partially embedded in the second end plate. In this way, the two filter medium bodies can be sealed against one another and fixed to one another at the second end face in addition to the first end face. The second side band can be embedded in the second end plate as described above for the first side band and the first end plate. In particular, the second side band and the second end plate can have further features described above in connection with the first side band and the second side band. One of the end plates can be an open end plate and the other end plate a closed end plate.

[0035] In addition to the first sideband, the second sideband can also have slits that extend into the folds of the second filter medium body. Preferably, the slits on one of the sidebands extend from its inner edge, and the slits on the other sideband extend from its outer edge. By expanding the sideband with outer slits and compressing the sideband with inner slits, a tapered filter element can be obtained without stresses or strains in the sidebands remaining small.

[0036] Preferably, a lining fleece is arranged on a peripheral surface of the second filter medium body facing away from the first filter medium body. The lining fleece prevents any activated carbon particles adhering to the second filter medium body, originating from the production process before the sideband was applied, from reaching the clean side.

[0037] A support body can be arranged on a peripheral surface of the second filter medium body facing away from the first filter medium body. The support body stabilizes the filter element, through which the flow typically flows toward the support body. For this purpose, the second filter medium body can be supported directly or indirectly on the support body. If a nonwoven lining is provided, this can be arranged between the second filter medium body and the support body. The support body can be a central support tube or an outer cage.

[0038] The scope of the present invention also includes a filter device, in particular a gas filter device, comprising a housing and a filter element according to the invention as described above, which can be arranged in the housing so that it separates a raw side from a clean side.

[0039] Also within the scope of the present invention is the use of a filter element according to the invention described above, in particular a filter device according to the invention described above, as a cathode air filter of a fuel cell.

[0040] Finally, the scope of the present invention includes a fuel cell having an anode and a cathode, between which an electrolyte is arranged, and having a filter element according to the invention described above, through which air can be conducted to the cathode.

[0041] Fuel cells often require a two-stage filtration of the air supplied to the cathode, particularly where harmful gases as well as particles need to be removed. The filter element according to the invention enables this through its advantageous design described above.

[0042] Short description of the drawings

[0043] Further features and advantages of the invention will become apparent from the following detailed description of exemplary embodiments of the invention, from the patent claims and from the figures of the drawing, which show details according to the invention. The features mentioned above and those explained in more detail can each be implemented individually or in groups in any expedient combination in variants of the invention. The features shown in the drawing are illustrated in such a way that the special features of the invention can be clearly seen. The drawing shows: Fig. 1 a first embodiment of a filter element according to the invention with a first and a second filter medium body in a schematic sectional view;

[0044] Fig. 2 shows an enlarged section of Figure 1 in the region of a first end face;

[0045] Fig. 3 shows an enlarged section of Figure 1 in the region of a second end face;

[0046] Fig. 4 shows a second embodiment of a filter element according to the invention with a first and a second filter medium body in a schematic sectional view;

[0047] Fig. 5 shows an enlarged section of Figure 4 in the region of a first end face;

[0048] Fig. 6 shows an enlarged section of Figure 4 in the region of a second end face;

[0049] Fig. 7 shows a filter device with the filter element of Fig. 4 in a schematic sectional view;

[0050] Fig. 8 shows a third embodiment of a filter element according to the invention with a first and a second filter medium body in a schematic sectional view;

[0051] Fig. 9 shows the filter element of Figure 8 in a further schematic sectional view, perpendicular to the sectional plane of Figure 8;

[0052] Fig. 10 shows the second filter medium body of the filter element of Figure 8 in a schematic perspective view obliquely from above;

[0053] Fig. 1 1 is a schematic bottom view of the second filter medium body of Figure 10;

[0054] Fig. 12 a schematic diagram of the covering of front edges of the second filter medium body with a slotted side band;

[0055] Fig. 13 shows a filter device with the filter element of Fig. 8 in a schematic sectional view;

[0056] Fig. 14 is a schematic sectional view of a pleated filter medium containing activated carbon;

[0057] Fig. 15 is a schematic diagram of a fuel cell according to the invention with a filter element according to the invention as a cathode air filter.

[0058] Embodiments of the invention

[0059] Figure 1 shows a filter element 10 designed as an air filter element. The filter element 10 has two annular, here hollow-cylindrical, filter medium bodies 12, 14. The first filter medium body 12 is arranged within the second filter medium body 14. The two filter medium bodies 12, 14 encompass a common longitudinal axis 16. The filter element 10 or the two filter medium bodies 12, 14 are fluidically connected in series. The second filter medium body 14 is arranged downstream of the first filter medium body 12. In this embodiment, the filter element 10 can be flowed through from the radial inside to the radial outside.

[0060] The first filter medium body 12 comprises a filter medium for particle filtration. The particle filtration medium here is a star-folded filter paper. Alternatively, the particle filtration medium could be a depth filtration medium.

[0061] The second filter medium body 14 has a filter medium 18 in the form of an adsorption medium, which in this case contains activated carbon. The second filter medium body 14 serves to remove harmful gases from the air stream to be filtered. The adsorption filter medium 18 is folded in a star shape (see Figure 14). Figure 14 also shows that, in the adsorption filter medium 18, a layer 20 containing activated carbon particles is enclosed between two layers of filter paper 22.

[0062] At a first end face 24 and a second end face 26, the two filter medium bodies 12, 14 are connected to each other and sealed against each other, see Figure 1.

[0063] At the first end face 24, the first filter medium body 12 is enclosed by a first end plate 28 (see also Figure 2). The first end plate 28 is an open end plate with a central opening 30 for the entry of air to be filtered. The first end plate 28 can be made of polyurethane foam.

[0064] The second filter medium body 14 is enclosed at the first end face 24 by a first side band 32. The first side band 32 is glued to the first end edges 34 of the filter medium 18. The second filter medium body 14 is thus sealed at the first end face 24. Furthermore, the first side band 32 prevents the escape of activated carbon particles.

[0065] The first side band 32 protrudes radially inward beyond the second filter medium body 14. Only in the area of ​​the projection is the first side band 32 embedded in the first end plate 28. A radially outward portion of the first side band 32 is exposed (on the side facing away from the second filter medium body 14). The first end plate 28 can be molded onto the first filter medium body 12 and the projecting portion of the first side band 32.

[0066] At the second end face 26, the first filter medium body 12 is enclosed by a second end plate 36 (see Figures 1 and 3). The second end plate 36 is a closed end plate. The second end plate 36 can be made of polyurethane foam.

[0067] The second filter medium body 14 is enclosed at the second end face 26 by a second side band 38. The second side band 38 is glued to the second end edges 40 of the filter medium 18. The second filter medium body 14 is thus sealed at the second end face 26. Furthermore, the second side band 38 prevents the escape of activated carbon particles.

[0068] The second side band 38 protrudes radially inward beyond the second filter medium body 14. Only in the area of ​​the projection is the second side band 38 embedded in the second end plate 36. A radially outward portion of the second side band 38 is exposed (on the side facing away from the second filter medium body 14). The second end plate 36 can be molded onto the first filter medium body 12 and the projecting portion of the second side band 38.

[0069] The first and second side bands 32, 38 may be made of a nonwoven material.

[0070] Figure 4 shows a filter element 42 with two filter medium bodies 12, 14 through which flow can occur in series from the radial outside to the radial inside. In filter element 42, the second filter medium body 14 is arranged within the first filter medium body 12. The two filter medium bodies 12, 14 are essentially designed as described above for filter element 10; in this respect, reference is made to the above description. The differences between filter elements 10 and 42 are primarily described below.

[0071] The second filter medium body 14 is provided with a first and second side band 32, 38 on the first and second end faces 24, 26, respectively (see also Figures 5 and 6). A first and second end plate 28, 36 is also provided on the first and second end faces 24, 26, respectively. The end plates 28, 36 can be made of polyurethane foam. The side bands 32, 38 are each completely embedded in the material of the first and second end plates 28, 36, respectively (see also Figures 5 and 6). In other words, the end plates 28, 26 enclose the side bands 32 and 38 on all sides.

[0072] A laminating fleece 46 is arranged on the second filter medium body 14 on a circumferential surface 44 facing away from the first filter medium body 12, i.e. radially inward here.

[0073] A support body 48, here in the form of a grid-like support tube, is also arranged on the radially inner circumferential surface 44. The lining fleece 46 is accommodated between the support body 48 and the second filter medium body 14. It is understood that the support body 48 could also be present if the lining fleece 46 were not provided.

[0074] Figure 7 shows a filter device 50 with the filter element 42, which is accommodated in a housing 52. An inlet 54 allows the entry of air to be filtered to the outside of the filter element 42. Filtered air can be discharged from the interior of the filter element 42 through an outlet 56.

[0075] The first end plate 28 is an open end plate with a central opening 30. The first end plate 28 has a sealing bead 58 (see also Figures 4 and 5) for sealing against the housing 50. Here, the sealing bead 58 surrounds the outlet 56.

[0076] The filter element 42 is closed at the second end face 26, with the support body 48 radially closing the second end plate 36. Thus, an air flow from the inlet 54 is first directed through the first filter medium body 12 and then through the second filter medium body 14 before the air flow leaves the housing 50 at the outlet 56.

[0077] Figures 8 and 9 show a filter element 60 having an oval cross-section. Flow passes through the filter element 60 from the radial inside to the radial outside. A first filter medium body 12 is arranged within a second filter medium body 14. The first filter medium body 12 comprises a filter medium for particle filtration. The second filter medium body 14 comprises a folded filter medium 18 in the form of an adsorption medium, which in this case contains activated carbon. The filter element 60, and in particular the two filter medium bodies, taper along their common longitudinal axis 16 from a first end face 24 to a second end face 26. An open first end plate 28 is arranged on the first end face 24 and encloses both the first filter medium body 12 and the second filter medium body 14. A first side band 32, which covers first end edges 34 of the second filter medium body 14, is completely embedded in the first end plate 28.

[0078] A closed second end plate 36 is arranged on the second end face 26, which encloses both the first filter medium body 12 and the second filter medium body 14. A second side band 38, which covers second end edges 40 of the second filter medium body 14, is completely embedded in the second end plate 36.

[0079] A support body 48 in the form of a grid-like outer cage surrounds the second filter medium body 14 on an outer peripheral surface 62. A laminating fleece 46 can be arranged between the support body 48 and the second filter medium body 14.

[0080] Figures 10 and 11 show the second filter medium body 14 of the filter element 60. The second filter medium body 14 is composed of two filter bellows 64, 66, each obtained by zigzag folding the filter medium 18 containing activated carbon and adsorbing harmful gases (see also Figure 14). The filter bellows 64, 66 are each sealed at their head ends 68 by headbands 70, which are adhesively bonded to the respective filter bellows 64, 66. The headbands 70 can be made of a nonwoven material and be angled in an L-shape, with a short leg extending circumferentially, here the inner circumferential side, on the second filter medium body 14. In order to obtain the annularly closed second filter medium body 14, the filter bellows 64, 66 are bent and a headband 70 of the filter bellows 64 is glued to a headband 70 of the filter bellows 66.In this way, the two filter bellows 64, 66 are each connected airtight at their two head sides 68 to one head side of the other filter bellows 64, 66.

[0081] In a corresponding manner, the second filter medium bodies 14 of the filter elements 10 or 42 can also be composed of multiple filter bellows. It is understood that the second filter medium bodies 14 of the filter elements 10, 42, or 60 can each also be composed of a single filter bellows, the two headbands of which are glued together to close the filter medium body 14 in the circumferential direction. Likewise, the second filter medium bodies 14 of the filter elements 10, 42, or 60 could be composed of more than two filter bellows.

[0082] The side bands 32, 38 are formed in two parts, wherein a section 32a, 32b or 38a, 38b of the first or second side band 32, 38 is connected to one of the filter bellows 64, 66.

[0083] The two side bands 32, 38 are each provided with slots 72, 74. On the first side band 32, the slots 72 extend radially inward from an outer edge 76, see Figure 10. On the second side band 38, the slots 74 extend radially outward from an inner edge 78, see Figure 11. The slots 72, 74 do not completely penetrate the side bands 32, 38 in the width direction (radial direction of the filter element 60). Figure 12 shows, by way of example for the first side band 32, that the slots 72 each extend into an outwardly open fold 79. Exactly one slot 72 engages in each fold 79.

[0084] In a corresponding manner, the slits 74 of the second side band 38 each extend into an inwardly open fold 81 (not shown in detail). On the second side band 38, too, exactly one slit 74 can engage in each fold 81.

[0085] Figure 13 shows a filter device 82 with the filter element 60, which is accommodated in a housing 52. An inlet 54 allows the air to be filtered to enter the interior of the filter element 60. Filtered air can be discharged from the outside of the filter element 60 through an outlet 56. In this embodiment, the filter element 60, with a seal 84 provided on the support body 48, lies sealingly against the housing 52 in order to separate the inlet 54 from the outlet 56. The support body 48 is closed between the seal 84 and the first end plate 28 in order to force flow first through the first filter medium body 12 and then through the second filter medium body 14.

[0086] Figure 15 shows a fuel cell 86. The fuel cell 86 has an anode 88, a cathode 90, and an electrolyte 92 arranged therebetween. The anode 88 and the cathode 90 can each be adjacent to a gas diffusion layer 93 on the outside. The anode 88 and the cathode 90 can be accommodated between side parts 94, 96 of a bipolar plate 98. Hydrogen can be conducted from a hydrogen inlet 100 to the anode 88 through the side part 94 of the bipolar plate 98. Oxygen or oxygen-containing air can be conducted from an air inlet 102 to the cathode 90 through the side part 96 of the bipolar plate 98. A filter device with a filter element arranged in a housing 52 is provided between the air inlet 102 and the cathode 88. The filter element may be one of the filter elements 10, 42 or 60 described above; the filter device may accordingly be a filter device 50 or 82 described above.The filter element 10, 42, 60 thus functions as a cathode air filter. Water generated in the fuel cell 86 can be drained through a water outlet 104. Electrical connections of the fuel cell 86 are not shown in detail.

[0087] In summary, the invention relates to a two-stage filter element with an inner and an outer filter media body through which flow can pass in series. The inner filter media body is arranged in an interior space of the outer filter media body. At least one of the filter media bodies has a folded filter medium, preferably containing activated carbon, which is covered at the end face by a side band. The side band is embedded in the circumferential direction continuously, at least in a radial partial region, in an end plate, which seals the other filter media body at the end face. The end plate can also seal the folded filter media body with the side band, wherein the side band can be completely embedded in the end plate. The side band can have slots in the region embedded in the end plate. List of reference symbols

[0088] Filter element 10 first filter medium body 12 second filter medium body 14

[0089] Longitudinal axis 16

[0090] Filter medium 18

[0091] Layer 20 containing activated carbon particles

[0092] Filter paper layer 22 first end face 24 second end face 26 first end plate 28 central opening 30 first side band 32

[0093] Sections 32a, 32b of the first side band 32 first end edges 34 second end plate 36 second side band 38

[0094] Sections 38a, 38b of the first side band 38 second front edges 40

[0095] Filter element 42

[0096] Circumferential area 44

[0097] Laminating fleece 46

[0098] Support body 48

[0099] Filter device 50

[0100] Housing 52

[0101] Entrance 54

[0102] Outlet 56

[0103] Sealing bead 58

[0104] Filter element 60

[0105] Circumferential area 62

[0106] Filter bellows 64, 66

[0107] Header pages 68

[0108] Headbands 70

[0109] Slots 72, 74

[0110] Outer edge 76

[0111] Inner edge 78

[0112] Folds 79, 81

[0113] Filter device 82

[0114] Seal 84

[0115] Fuel cell 86

[0116] Anode 88

[0117] Cathode 90

[0118] Electrolyte 92

[0119] Gas diffusion layer 93

[0120] Side panels 94, 96

[0121] Bipolar plate 98

[0122] Hydrogen inlet 100

[0123] Air intake 102

[0124] Water outlet 104

Claims

Claims 1. Filter element (10; 42; 60), in particular a gas filter element, with a first and a second annular filter medium body (12, 14), wherein one of the filter medium bodies (12, 14) is arranged within the other filter medium body (12, 14) is arranged and wherein the two filter medium bodies (12, 14) can be flowed through one after the other, wherein the filter element (10; 42; 60) has an end plate (28) on one end face (24), wherein at least the second filter medium body (14) has a folded filter medium (18), wherein end edges (34) of the folded filter medium (18) of the second filter medium body (14) are sealed on the end face (24) by a side band (32), and wherein the side band (32) is at least partially embedded in the end plate (28).

2. Filter element (10) according to claim 1, wherein the side band (32) projects in the radial direction beyond the folded filter medium (18) of the second filter medium body (14).

3. Filter element (10) according to claim 1 or 2, wherein only a radial portion of the side band (32) is embedded in the end plate (28).

4. Filter element (42; 60) according to claim 1 or 2, wherein the side band (32) is completely embedded in the end plate (28).

5. Filter element (42) according to one of the preceding claims, wherein the second filter medium body (14) with the side band (32) is arranged radially inside the first filter medium body (12).

6. Filter element (10; 60) according to one of the preceding claims, wherein the second filter medium body (14) with the side band (32) surrounds the first filter medium body (12) on the outside.

7. Filter element (10; 42; 60) according to one of the preceding claims, wherein the side band (32) contains a nonwoven material, in particular a filter fleece, a woven fabric, in particular a filter fabric, or a grid material, in particular a filter grid.

8. Filter element (10; 42; 60) according to one of the preceding claims, wherein the second filter medium body (14) has at least one folded filter bellows (64, 66) whose head sides (68) are sealed by headbands (70), wherein the ring shape of the second filter medium body (14) is obtained by gluing two headbands (70) together.

9. Filter element (10; 42; 60) according to claim 8, wherein the second filter medium body (14) is obtained from at least two filter bellows (64, 66), wherein circumferentially adjacent filter bellows (64, 66) are glued together at their respective headbands (70).

10. Filter element (60) according to one of the preceding claims, wherein the filter element (60) tapers in the axial direction.

11. Filter element (60) according to one of the preceding claims, wherein the side band (32) has slots (72) extending into folds (79) of the second filter medium body (14).

12. Filter element (60) according to claim 11, wherein at least in a partial area comprising at least five consecutive folds (79) open on a common circumferential side, preferably over the entire circumference, of the second filter medium body (14), a slot (72) extends into each fold (79) open on the common circumferential side of the partial area.

13. Filter element (10; 42; 60) according to one of the preceding claims, wherein the filter element (10; 42; 60) has a second end plate (36) on a second end face (26), wherein end edges (40) of the second filter medium body (14) on the second end face (26) are sealed by a second side band (38), and wherein the second side band (38) is at least partially embedded in the second end plate (36).

14. Filter element (60) according to claim 13 and according to claim 11 or 12, wherein the second side band (38) has slits (74) extending into the folds (81) of the second filter medium body (14), the slits (74) on one of the side bands (38) extending from its inner edge (78) and the slits (72) on the other side band (32) extending from its outer edge (76).

15. Filter element (10; 42; 60) according to one of the preceding claims, wherein the folded filter medium (18) of the second filter medium body (14) contains activated carbon.

16. Filter element (10; 42; 60) according to one of the preceding claims, wherein a laminating fleece (46) is arranged on a peripheral surface (44; 62) of the second filter medium body (14) facing away from the first filter medium body (12).

17. Filter element (42; 60) according to one of the preceding claims, wherein a support body (48) is arranged on a peripheral surface (44; 62) of the second filter medium body (14) facing away from the first filter medium body (12).

18. Use of a filter element (10; 42; 60) according to one of claims 1 to 17 as a cathode air filter of a fuel cell (86).

19. Fuel cell (86) with an anode (88) and a cathode (90), between which an electrolyte (92) is arranged, and with a filter element (10; 42; 60) according to one of claims 1 to 17, through which air can be conducted to the cathode (90).

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