Filtration system

Abstract

The invention relates to a filtration system (100) having a housing (102) in which a first filtration element (10) designed as a hollow body and a second filtration element (40) arranged coaxially and concentrically in the interior (30) of the first filtration element (10) are arranged. A central opening (22) of an end disk (18) of the first filtration element (10) at its end face is closed in a fluid-tight manner by a cover (50) closing the corresponding end face (46) of the second filtration element (40). A sealing interface (80) is arranged between the two end faces (16, 46) of the filtration elements (10, 40). The invention also relates to a filtration element (10, 40) for this type of filtration system (100).

Description

Technical Field

[0001] The present invention relates to a filter element and a filter system, particularly for air, especially for the intake of internal combustion engines in motor vehicles. The filter element and the filter system can be used for air filtration of fuel cells, particularly as a cathode air filter. Furthermore, the filter element or the filter system can be additionally configured to adsorb harmful gases.

Background Art

[0002] European Patent Application Publication No. 3003533 discloses a filter system in which a conical secondary filter element is inserted inside the clean side of a cylindrical primary filter element. Annular end discs are arranged on both end faces of the filter element so that both sides of the filter element are open. The primary filter element is axially sealed against the housing cover. The end face of the secondary filter element facing the housing cover is closed and supported by the housing cover.

Summary of the Invention

[0003] An object of the present invention is to provide a filter system that can reduce the material and weight of the housing.

[0004] A further object of the present invention is to provide a filter element for such a filter system.

[0005] The above-mentioned objective is solved by the filtration system described in claim 1, according to one aspect of the present invention. The filtration system comprises a housing having a fluid inlet and outlet, wherein a first filtration element, designed as a hollow body having a filter medium, particularly a hollow cylindrical body, is disposed within the housing, and a second filtration element is disposed inside the first filtration element, wherein the first and second filtration elements are arranged coaxially and concentrically with respect to a longitudinal axis, the first filtration element includes a first end disc disposed on the outlet end face and a second end disc disposed on the opposite end face, each end disc having a central opening and extending substantially annularly over each end face of the filter medium, the second filtration element includes a first end face on the outlet side and a second end face located on the opposite side of the outlet end face and fluid-tightly closed by a cover, the opening of the second end disc of the first filtration element being fluid-tightly closed by the cover, and a seal interface is disposed between the second end face of the first filtration element and the second end face of the second filtration element. Through this sealing interface, the two filtration elements are directly sealed to each other.

[0006] According to a further aspect of the present invention, the object is a filtration element for a filtration system, comprising a filter medium that is folded in a zigzag manner and formed into a hollow body, a first end disc positioned on one end face, and a second end disc positioned on the opposite end face, each of the two end discs having a central opening and extending substantially annularly over the end face of the filtration element, the sealing surface or region of the seal interface being resolved by the filtration element positioned on the end face intended to be on the opposite side of the outlet to the clean air side in the installed state.

[0007] According to a further aspect of the present invention, the object is a filtration element for a filtration system comprising a single-layer or multi-layer filter media disposed on a support tube, a first socket disposed on one end face, and a second cover disposed on the opposite end face, wherein the cover is resolved by a filtration element including at least one sealing surface or at least one sealing element intended to form a sealing interface with other filtration elements in the installed state.

[0008] Preferred embodiments and advantages of the present invention are derived from the appended claims, specification, and drawings.

[0009] A filtration system is proposed comprising a housing having a fluid inlet and outlet, wherein a first filtration element, designed as a hollow body having a filter medium, is positioned within the housing around its longitudinal axis, and a second filtration element is positioned inside the first filtration element. The two filtration elements are positioned coaxially and concentrically around the longitudinal axis of the first filtration element. The longitudinal axis of the filtration elements may coincide with the longitudinal axis of the filter housing. However, the filtration elements may also be positioned eccentrically with respect to the housing axis of the filter housing. The first filtration element includes a first end disc positioned on the outlet end face and a second end disc positioned on the opposite end face. Each end disc has a central opening and extends substantially annularly over the respective end faces of the filter medium. The second filtration element includes a first end face on the outlet side and a second end face located opposite the outlet end face and fluid-tightly closed by a cover. The opening of the second end disc is fluid-tightly closed by a cover, and a seal interface is located between the second end face of the first filtration element and the second end face of the second filtration element.

[0010] The seal interface includes at least one seal surface provided on one side of the filter element and at least one seal element provided on the other side of the filter element. The seal element may be formed from a foamed polymer foamed onto one side of the filter element, or from an injection-molded thermoplastic material. The foamed polymer can be polyurethane in particular. In this case, the seal element and end disc may be formed from the same material. Alternatively, the seal element may be a two-component (2K) component in which a thermoplastic elastomer is molded on a thermoplastic carrier present on one side of the filter element. The carrier can be made of a polymer, particularly PP or PA. The seal element may also be a seal element bonded to the carrier, particularly an extruded seal element.

[0011] Advantageously, the seal interface is directly located between the two filtration elements. Complex additional parts can be avoided. The first filtration element is also referred to as the primary element, and the second filtration element as the secondary or safety element. Preferably, the filter media of the first filtration element is a filter media folded in a zigzag pattern and configured as a hollow body. The hollow body can be designed to be cylindrical or conical. Various bottom surfaces are possible, but preferably the bottom surface is circular or elliptical. In the case of a cylindrical filtration element, the end disc is correspondingly annular. The filter media is preferably arranged around a support tube. The end disc is preferably formed of a foamed polymer, particularly polyurethane. The housing is advantageously configured coaxially with the longitudinal axis of the filtration element, and in particular the housing has an outlet as a socket arranged coaxially with the longitudinal axis. The second filtration element has an end face closed by a cover on the side of the housing located opposite the outlet. The filter media of the second filtration element is preferably a single-layer or multi-layer wound filter media arranged on a support tube. Alternatively, the filter material of the second filtration element may be a collapsible bellows formed in a hollow body. Thus, the sealing interface is located on the side of the housing opposite the outlet. The cover may be designed as a single piece together with the support tube of the second filtration element and can be made of a rigid plastic material, particularly polymers such as PP or PA. In particular, if the second filtration element is designed as a collapsible bellows, the cover may be made of a flexible plastic material, particularly foamed polyurethane, which advantageously simultaneously forms a pleated end-face sealing action.

[0012] The filtration system is, for example, an air filtration system, particularly an air filtration system for an internal combustion engine, preferably an air filtration system for an internal combustion engine or fuel cell in an automobile.

[0013] According to a useful embodiment, the seal interface includes at least one seal surface provided on the support tube of the first filter element, located opposite the clean side outlet, and at least one seal element provided on the second filter element, which seals the seal surface in the axial and / or radial directions.

[0014] Preferably, the sealing element is positioned in the second filtration element either directly on the cover or at a distance from the cover. Furthermore, the first filtration element may be supported on its outside by a housing.

[0015] According to a useful embodiment, the seal interface includes a seal element, particularly a seal ring, positioned on a circumferential projection projecting axially away from the cover at the outer end face of the cover, the seal element providing a radial seal to the support tube of the first filter element. The seal element may be formed from a foamed polymer foamed on or around the projection, or from an injection-molded thermoplastic material. The foamed polymer can be polyurethane in particular. The seal member may also be a two-component (2K) part in which the thermoplastic material is molded on the projection.

[0016] According to a useful embodiment, the seal interface includes a seal element positioned on a circumferentially extending edge of the cover and sealing radially against the support tube of the first filter element. The seal element may be a molded body of a foamed polymer that is foam-molded on the edge and seals against the support tube of the first filter element on its outer surface, or it may be a thermoplastic material that is molded on the edge.

[0017] According to a beneficial embodiment, the seal interface includes a seal element, particularly a seal ring or seal projection, provided on the end face of the second filter element, particularly on the cover. This seal element axially seals against the rim of the support tube of the first filter element, which protrudes radially inward. A circumferentially extending ring embedded in the seal element may be placed on the cover, thereby enabling a stable connection between the seal element and the second filter element. The seal element is preferably a foamed polymer, particularly polyurethane, or a thermoplastic material. Advantageously, the end disc of the first filter element overlaps at least partially with the inwardly protruding rim. This allows for improved seal between the central tube and the end disc and stable support of the seal surface. The radially inwardly protruding rim of the support tube of the first or outer filter element may have a groove that engages with the seal element, particularly the seal projection. The seal element may axially seal against the bottom of the groove and / or against the axial end face of the projection defining the groove.

[0018] According to a beneficial embodiment, the seal interface includes a region of the second end disc of the first filter element located axially opposite the clean side outlet, and at least one seal surface provided on the second filter element. Advantageously, the end disc can be shaped to a desired form by a suitable mold during manufacturing. The end disc can provide its sealing function to the second filter element with or without support in some embodiments.

[0019] Advantageously, the second end disc of the first filtration element protrudes radially inward beyond the filter media. In connection with this, for example, the support tube may be inclined inward and / or have an inwardly protruding rim at its axial end. In this way, the inwardly protruding end disc can be supported and stabilized in this region. For example, if the sealing element is part of the first filtration element, the support tube may be configured to reinforce the flexible sealing element or to mount the sealing element. If the second filtration element has or carries the sealing element, the support tube may be configured as a mating contour to create a sealed connection between the two filtration elements.

[0020] According to a useful embodiment, the region is located on the inner rim of the second end disc of the first filtration element, and the region seals against a sealing surface provided on the radially outer circumferential surface of a circumferential projection located on the cover, projecting axially away from the cover. In particular, the axially projecting portion provided on the second housing web However, it may engage with a groove in the second end disc. Advantageously, the end disc is supported by the housing such that the end disc forming the sealing element is reliably in contact with the sealing surface of the second filtration element.

[0021] According to a useful embodiment, the region of the second end disk of the first filtration element radially seals against a sealing surface located inside a circumferentially extending projection in the cover. This projection protrudes axially away from the cover, protrusion This engages with the groove of the end disc. In particular, the inner rim of the second end disc of the first filtration element may be radially supported by a web projecting axially inward provided on the second housing portion. This ensures stable retention of the end disc that forms the sealing element of the seal interface.

[0022] According to a beneficial embodiment, the region is located on the inner rim of the second end disc of the first filtration element, and the inner rim seals against a sealing surface provided on the radially outer circumferential surface of a circumferential projection located on the cover, projecting axially away from the cover. The end disc may have an axial projection in a region that contacts or abuts the sealing surface of the second filtration element in order to enable a large sealing surface.

[0023] According to a beneficial embodiment, the region is located on the axially inward end face of a radial projection of the second end disc of the first filtration element. This radial projection extends circumferentially within the cross-section of the filter material and seals against a sealing surface provided on the end face of the cover. In particular, the support tube may include a circumferentially extending rim that protrudes radially inward and is embedded in the radial projection. This allows for stable support of the sealing interface.

[0024] According to a beneficial embodiment, the end face of the second housing component is curved inward. This ensures that only the appropriate filtration element is inserted into the housing.

[0025] According to a beneficial embodiment, the end face of the second housing portion has an opening that extends at least partially onto the second end face of the second filter element. When the second filter element is installed, the opening is covered by the end face cover of the filter element. The sealing action is achieved by sealing points that are at least partially concentric in at least two of the components of the first filter element, the second filter element, and the second housing portion. The opening ensures that only the appropriate filter element is inserted into the housing. It is possible to visually confirm that the appropriate second filter element is inserted without opening the housing. The weight is reduced because the amount of housing material is reduced.

[0026] According to a further aspect of the present invention, there is provided a filter element for a filtration system according to the present invention, particularly folded in a zigzag shape, comprising a filter medium formed in a hollow body, a first end disk disposed on an end face, and a second end disk disposed on an end face located on the opposite side thereof. The two end disks each have a central opening and extend substantially annularly on the end face of the filter medium (in the case of a folded filter medium, on the folds), and the sealing surface or the region of the sealing element of the sealing interface is disposed on the end face intended to be located on the opposite side of the outlet on the clean air side in the installed state. The filter element is preferably designed in a cylindrical shape, particularly an annular shape, but can also be designed in a conical shape.

[0027] Advantageously, the filter element can be a main element of the filtration system. The main element can be fluid-tightly connected to a second filter element, preferably a sub-element, by a sealing interface. For example, the end disk can be formed of a foamed polymer, particularly polyurethane. The configuration of the filter element is compact, and additional parts for sealing can be reduced. The installation into the filtration system can be simplified.

[0028] According to a beneficial embodiment, the filter medium is disposed around a support tube, and the support tube includes a sealing surface. During manufacturing, the support tube can be appropriately designed to form the sealing surface as a mating contour for the sealing element. Alternatively, the support tube can be configured to attach the sealing element and / or reinforce a soft sealing element. The support tube may have a rim protruding radially inward where the sealing surface is disposed. In particular, the axially inner portion of the rim may form the sealing surface.

[0029] According to a beneficial embodiment, on the end face intended to be located on the opposite side of the outlet on the clean air side in the installed state, the end disk includes a region on the sealing element side of the sealing interface. The end disk advantageously extends annularly radially inward beyond the filter medium. This radially inner annular region can form the sealing element of the sealing interface. In some embodiments, this region has a groove that interacts with the sealing surface of the mating member of the sealing interface.

[0030] Thus, in this embodiment, in the filtration system into which the filtration element is inserted, since it is not necessary to design the end disk of the outer filtration element to be closed, the weight can be further advantageously reduced. Since there is an opening at the bottom of the outer filtration element, the material of the end disk can be reduced.

[0031] According to a further aspect of the invention, there is provided a filtration element for a filtration system according to the invention, comprising a single-layer or multi-layer filter medium arranged on a support tube, a first circumferentially extending socket arranged on the end face and protruding axially, and a second cover arranged on the end face located on the opposite side thereof, the cover including at least one sealing surface or at least one sealing element intended to form a sealing interface with other filtration elements in the installed state. The filter medium can be wound around the support tube or formed into a hollow body that surrounds the support tube by being folded in a zigzag manner.

[0032] Advantageously, the filtration element can be a sub-element of the filtration system. The sub-element can be fluid-tightly connected to a further filtration element, preferably a main element, by a sealing interface. The filtration element is preferably designed to be cylindrical, particularly annular, but can also be designed to be conical.

[0033] Alternatively or in addition thereto, the filtration element can be designed for harmful gas adsorption. kill For harmful gas adsorption, the filtration element may be composed of a corresponding suitable filter medium, particularly a filter medium containing activated carbon.

[0034] According to a beneficial embodiment, the cover is provided with circumferentially extending projections that project axially away from the cover, and these circumferentially extending projections support a sealing element. Advantageously, the projections are embedded in the sealing element. For example, the sealing element can be formed from a foamed polymer, particularly polyurethane, or a thermoplastic material. In particular, when the second filtration element is designed as a foldable bellows having foamed end discs, the projections themselves can constitute the foamed polymer and form the sealing element. In this case, the projections can be manufactured in a simple manner integrally with the end discs.

[0035] According to a beneficial embodiment, the sealing element is positioned at the edge of the cover or support tube. Advantageously, a foamed polymer, particularly polyurethane, or thermoplastic material can be positioned at the edge.

[0036] According to a useful embodiment, the cover is provided with circumferentially extending projections that protrude axially outward, serving as sealing surfaces of the sealing interface. The projections can be designed in a manner appropriate to form the sealing surface or sealing interface. [Brief explanation of the drawing]

[0037] Further advantages can be derived from the following description of the drawings, which illustrate embodiments of the present invention. The drawings, specification, and claims contain a number of combined features. Those skilled in the art can appropriately consider and combine these features, both individually and individually, to provide further combinations. These are illustrated below.

[0038] [Figure 1] This is a cross-sectional view showing a filtration system according to one embodiment of the present invention. [Figure 2] This is a cross-sectional view showing details of a filtration system according to one embodiment of the present invention, which has a radial sealing action between a first filtration element and a second filtration element. [Figure 3] This is a cross-sectional view showing details of a filtration system according to a further embodiment of the present invention, which has a radial sealing action between a first filtration element and a second filtration element. [Figure 4] This is a detailed cross-sectional view of the filtration system shown in Figure 1, which has an axial sealing action between the first and second filtration elements. [Figure 5] This is a cross-sectional view detailing a filtration system according to a further embodiment of the present invention, which has a radial sealing action between a second filtration element and the end disc of the first filtration element. [Figure 6] This is a cross-sectional view showing details of a filtration system according to a further embodiment of the present invention, which has a radial sealing action between a first filtration element and a second filtration element. [Figure 7] This is a cross-sectional view showing details of a filtration system according to a further embodiment of the present invention, which has a radial sealing action between a first filtration element and a second filtration element. [Figure 8] This is a cross-sectional view showing details of a filtration system according to a further embodiment of the present invention, which has an axial sealing action between a first filtration element and a second filtration element. [Figure 9] This is a cross-sectional view of a filtration system according to a further embodiment. [Figure 10] This is a cross-sectional view showing details of the embodiment shown in Figure 9. [Modes for carrying out the invention]

[0039] In the diagrams, identical or similar components are indicated by the same reference symbol. These diagrams are for illustrative purposes only and should not be understood as limiting.

[0040] In the embodiments shown in Figures 1 to 4, the seal interface 80 includes seal elements 60, 62, and 64 provided on the cover 50 of the second filter element 40, and a seal surface 25 provided on the support pipe 24 of the first filter element 10.

[0041] Figures 1 and 4 show a filtration system 100 according to a first embodiment of the present invention, where Figure 1 is a longitudinal cross-sectional view of the entire filtration system 100, and Figure 4 is a detailed view of the filtration system 100 of Figure 1. For example, the filtration system 100 is an air filtration system, particularly an air filtration system for an internal combustion engine, preferably an air filtration system for an internal combustion engine of an automobile, or a cathode air filter for a fuel cell of an automobile.

[0042] The filtration system 100 comprises a housing 102, which has, for example, an inlet 108 located tangentially to the housing 102 and hidden by the housing 102 in the figure, and a socket-shaped outlet 110 for fluid located coaxially with the longitudinal axis 70. The inlet 108 and outlet 110 are located, for example, at the opposing axial ends of the housing 102. The housing 102 includes, for example, a first housing component 104 which is a housing pot and a second housing component 106 which is, for example, a housing cover. The housing pot can be fixedly mounted, and the housing cover can be removed from it to access the inside of the housing.

[0043] Inside the housing 102, a hollow cylindrical first filtration element 10 is arranged coaxially with the longitudinal axis 70. Inside the first filtration element 10, 30, a second filtration element 40 is arranged coaxially with the longitudinal axis 70 and concentrically with the first filtration element 10.

[0044] In the illustrated embodiment, the longitudinal axis of the housing 102 coincides with the longitudinal axes of the first filter element 10 and the second filter element 40, so only a single common longitudinal axis 70 is referenced. However, an embodiment is also conceivable in which the first filter element 10 and the second filter element 40 are arranged concentrically with respect to a longitudinal axis different from the longitudinal axis of the filter housing. In such a case, the filter elements would be eccentrically positioned within the filter housing.

[0045] The first filtration element 10, also called the main element 10, includes a filter medium 11 positioned on the support tube 24. The first filtration element 10 includes a first end disc 14 positioned on the outlet end face 12 and a second end disc 18 positioned on the opposite end face 16. The end discs 14 and 18 each have openings 21 and 22, respectively, and each end face 1 of the filter medium 11 2 , extending substantially in an annular shape on 16. The filter material 11 is folded, for example, in a zigzag shape. The openings 21 and 22 in the illustrated embodiment are arranged coaxially with respect to the longitudinal axis 70.

[0046] The second filtration element 40, also called the sub-element 40, includes a filter medium 47 positioned on the support tube 48. For example, the filter medium 47 is applied on the support tube 48 as a single layer or multiple layers. The second filtration element 40 includes a first end face 42 on the outlet side and a second end face 46 located opposite the outlet end face 42. The first end face 42 is open and forms a socket 44, which is connected to the first housing component 104 at the socket-shaped outlet 110 and is screwed in, for example, by an external thread at the socket 44 of the second filtration element 40, though not specifically specified.

[0047] The second filtration element 40 functions as a safety element when replacing the main filtration element 10, but it can also be configured as a harmful gas filtration element and adsorb harmful gases. For this purpose, the filter material 47 may contain activated carbon.

[0048] The direction of fluid flow between the inlet 108 and outlet 110 through both filtration elements 10 and 40 is indicated by thick arrows. Fluid flows radially 74 through the filtration elements 10 and 40 from the outside to the inside. The first filtration element 10 can be withdrawn from the housing 102 while the second filtration element 40 is connected to the second housing portion 104, thereby protecting the clean-side outlet 110 from unfiltered fluid.

[0049] The second filtration element 40 is fluid-tightly closed by the cover 50 at its second end face 46, which is located opposite the clean-side outlet 110. The cover 50 fluid-tightly closes the opening 22 of the second end disc 18 of the second filtration element 40. To fluid-tightly close the opening 22, a seal interface 80 is positioned between the second end face 16 of the first filtration element 10 and the second end face 46 of the second filtration element 40. The support tube 48 of the second filtration element 40 and the cover 50 are preferably designed as a single unit.

[0050] In the end face regions of the filter elements 10 and 40 located opposite the clean-side outlet 110, the seal interface 80 typically includes at least one seal surface provided on one of the filter elements 10 and 40, and at least one seal element provided on the other of the filter elements 10 and 40. The second filter element 40 fluid-tightly closes the opening 22 of the end disk 18 of the first filter element 10 without requiring any additional parts. Depending on the embodiment, the seal element can seal in the axial direction 72 or the radial direction 74.

[0051] In the embodiment shown in Figure 1, which is shown in an enlarged view in Figure 4, the seal interface 80 includes a seal surface 25 provided on the support tube 24 of the first filter element 10 and an annular seal element 64 provided on the cover 50. The support tube 48 of the second filter element 40 and the cover 50 are preferably designed as a single unit. The seal element 64 is positioned on a projection 54 extending circumferentially on the cover 50, which protrudes outward in the axial direction 72 at the end face 46 of the second filter element 40. 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 axially at the seal surface 25 against the rim 26 of the support tube 24, which protrudes inward in the radial direction 74. The rim 26 of the support tube 24 abuts against the end disc 18.

[0052] In the second housing portion 106, the housing for the first filter element 10 is provided such that the first filter element 10 is in contact with the ring 116 surrounding the filter element 10 on the outside in the region of the second end disk 18. The first filter element 10 is supported at the bottom of the second housing portion 106 by a support knob which is not further specified.

[0053] In the illustrated embodiment, the second housing component 106 is curved inward so as to have a recess on its end face 112 in the region of the opening 22 of the end disk 18. This recess protrudes into the opening 22.

[0054] Since the basic configuration of the filtration elements 10, 40 and the housing 102 is substantially identical in various embodiments, in order to avoid unnecessary repetition, only significant differences in the seal interface 80 will be described in further embodiments.

[0055] Figure 2 is a cross-sectional view showing details of a filtration system 100 according to a further embodiment of the present invention, which includes a seal interface 80 having a radial sealing action between the first and second filtration elements 10 and 40.

[0056] The seal interface 80 includes a seal element 60 designed as a seal ring, which protrudes axially 72 outward from the outer end face of the cover 50 in a direction away from the cover 50 and is positioned on a circumferentially extending projection 52 embedded in the seal element 60. The seal element 60 seals radially 74 against the seal surface 25 of the support tube 24 of the first filter element 10. The support tube 24 includes a section of narrowing in the region of the seal surface 25 of the first filter element 10.

[0057] The first filtration element 10 is housed in the housing portion of the second housing component 106 and is surrounded radially outward by a ring 116. As described above, the bottom of the second housing component 106 has a recess on its end face 112 in the area of ​​the opening 22 of the end disc 18 of the first filtration element 10.

[0058] Figure 3 is a cross-sectional view showing details of a filtration system 100 according to a further embodiment of the present invention, which includes a seal interface 80 having a radial sealing action between the first and second filtration elements 10 and 40.

[0059] The seal interface 80 is positioned on the edge 51 of the cover 50 and includes a seal element 62 that seals radially 74 against the support tube 24 of the first filter element 10. The seal element 62 has an L-shaped cross-section including a leg projecting axially 72 and a leg projecting radially 74 inward. The seal element 62 can be molded or its edge 51 can be bordered with a foamed polymer.

[0060] The support pipe 24 includes a section of narrowing in the region of the sealing surface 25 of the first filtration element 10.

[0061] The first filtration element 10 is housed within the housing portion of the second housing component 106 and is surrounded radially outward by a ring 116. As described above, the bottom of the second housing component 106 has a recess on its end face 112 in the area of ​​the opening 22 of the end disc 18 of the first filtration element 10.

[0062] In the embodiments shown in Figures 5 to 8, the seal interface 80 includes the region 15 of the second end disk 18 of the first filter element 10 and the seal surface 45 of the second filter element 40 as seal elements.

[0063] Figure 5 is a cross-sectional view showing details of a filtration system 100 according to a further embodiment of the present invention, which has a radial sealing action between the first and second filtration elements 10 and 40.

[0064] Region 15 is located on the inner rim of the second end disc 18 of the first filtration element 10 and seals against a sealing surface 45 provided on the radially outer circumferential surface of a circumferentially extending projection 52 that is located on the cover 50 and projecting away from the cover 50 in the axial direction 72. The web 114 projecting in the axial direction 72 in the second housing portion 106 engages with a groove 17 in the second end disc 18. As a result, the end disc 18 is supported by the second housing portion 106 of the housing 102. This eliminates the need for an outer ring 116 (Figures 2, 3, and 4) radially positioned relative to the first filtration element 10 for housing the first filtration element 10 in the second housing portion 106.

[0065] In this embodiment, the second housing portion 106 is not curved in the area of ​​the opening 22 of the second end disk 18 of the first filtration element 10, and is designed to be open so that the cover 50 is visible from the outside.

[0066] Figure 6 is a cross-sectional view showing details of a filtration system 100 according to a further embodiment of the present invention, which has a radial sealing action between the first and second filtration elements 10 and 40.

[0067] The region 15 of the second end disc 18 of the first filtration element 10 seals radially 74 against the inner sealing surface 45 of a projection 56 extending circumferentially from the cover 50. The projection 56 protrudes axially 72 away from the cover 50 and is located on the outer rim of the cover 50. The end disc 18 extends beyond the rim region of the cover 50 together with the radial projection 20. The projection 56 engages with the groove 19 of the radial projection 20 of the end disc 18. The inner circumference of the second end disc 18 of the first filtration element 10 is supported radially 74 by a web 118 protruding axially 72 inward in the second housing portion 106 and is fixed radially 74 between the web 118 and the ring 116 of the second housing portion 106.

[0068] In this embodiment as well, the second housing portion 106 is not curved in the area of ​​the opening 22 of the second end disk 18 of the first filtration element 10, and is configured to be open so that the cover 50 is visible from the outside.

[0069] Figure 7 is a cross-sectional view showing details of a filtration system 100 according to a further embodiment of the present invention, which has a radial sealing action between first and second filtration elements 10, 40. The seal interface 80 includes a region 15 provided on the second end disc 18 of the first filtration element 10, located opposite the clean-side outlet 110 (Figure 1), and at least one seal surface 45 provided on the second filtration element 40, wherein the region 15 of the second end disc 18 of the first filtration element 10 is positioned to seal against this seal surface 45.

[0070] The second end disc 18 of the first filtration element 10, together with the radial projection 20, protrudes radially 74 inward beyond the filter material 11.

[0071] Region 15 is located on the inner rim of the second end disc 18 of the first filtration element 10 and is positioned on the cover 50, sealing against a sealing surface 45 provided on the radially outer circumferential surface of a circumferentially extending projection 52 that protrudes axially 72 outward from the cover 50.

[0072] In this embodiment, the bottom of the second housing portion 106 is curved, and the recess of the end face 112 protrudes into the opening 22. The filtration element 10 is housed in the housing portion of the second housing portion 106 and is surrounded by the support ring 116 in the area of ​​the second end disk 18.

[0073] Figure 8 is a cross-sectional view showing details of a filtration system 100 according to a further embodiment of the present invention, which has an axial sealing action between the first and second filtration elements 10 and 40.

[0074] Region 15 is located on the axially inward end face 58 of a radial projection 20 extending circumferentially within the cross-section of the filter material 11 on the second end disc 18 of the first filtration element 10, and this projection seals against a sealing surface 45 provided on the end face of the cover 50. The support tube 24 includes a rim 23 that projects radially 74 inward and is embedded in and reinforced by the radial projection 20 of the second end disc 18. The second end disc 18 can axially support the sealing interface 80 in this region.

[0075] Figure 9 shows a further embodiment of the filtration system 100, in which the inner filtration element 40 includes a filter medium 47 in the form of a collapsible bellows arranged around a support tube 48. At the end faces, the open folds are fluid-tightly closed by end discs 41, 49, respectively. The end discs 41, 49 are preferably formed of an elastic material, particularly PUR foam. The upper end disc 49 is an open annular end disc and includes circumferentially extending sealing beads that seal against the socket 110. The lower end disc 41 is also annular and surrounds the cover 50 of the support tube 48. The support tube 48 or cover 50 is partially embedded in the material of the end discs 41. Alternatively, the cover 50 as part of the support tube 48 can be omitted by making the end discs 41 in a disc shape and covering the cavity surrounded by the filtration element 40 at the end faces.

[0076] In Figure 10, the details of the filtration system shown in Figure 9 are illustrated in the region of the sealing interface 80 of the lower end discs 18, 41. The two filtration elements 10, 40 are axially sealed to each other. The support tube 24 has an annular rim 27 that protrudes radially 74 inward and is partially embedded in the material of the end disc 18. Radially inward, the annular rim 27 has a groove 29 whose radially outward side is defined by an annular projection 59. This groove 29 functions to receive an axial annular sealing projection 43 provided on the lower end disc 41 of the inner filtration element 40. The annular projection 59 of the rim 27 abuts axially against the flat axial end face of the end disc 41 of the inner filtration element 40. This configuration ensures a reliable axial sealing action between the two filtration elements 10, 40. The lower end disc 41 of the inner filtration element 40 simultaneously forms the sealing action of the folds and the interface with the outerly positioned filtration element 10, thus eliminating the need for additional sealing elements.

[0077] Advantageously, the inner filter element 40 can be a filter element for adsorbing harmful gases. For this purpose, the filter element is designed to be suitable for adsorbing harmful gases. Preferably, the filter material contains activated carbon.

[0078] Of course, further sealing configurations are also possible for sealing the two filtration elements 10, 40, which are designed as foldable bellows. For example, the radially outer portion of the lower end disc 41 of the inner filtration element 40 can be sealed against the rim of the support tube 24 of the outer filtration element 10. This rim protrudes axially to constitute a radial sealing action, as in the embodiment of Figure 2 or Figure 3.

Claims

1. A filtration system (100) comprising a housing (102) having a fluid inlet (108) and an outlet (110), A first filtration element (10), designed as a hollow body having a filter medium (11), is placed inside the housing (102), and a second filtration element (40) is placed inside (30) the first filtration element (10). The first filtration element (10) and the second filtration element (40) are arranged coaxially and concentrically with respect to the longitudinal axis (70). The first filtration element (10) includes a first end disc (14) positioned on the outlet end face (12) and a second end disc (18) positioned on the opposite end face (16), wherein each end disc (14, 18) has a central opening (21, 22) and extends substantially annularly on each end face (12, 16) of the filter material (11). The second filtration element (40) includes a first end face (42) on the outlet side and a second end face (46) located on the opposite side of the outlet end face (42) and fluid-tightly closed by the cover (50), In order to fluidly close the opening (22) of the second end disk (18), a seal interface (80) is provided between the first filter element (10) and the second filter element (40) in the end face region of the filter elements (10, 40) located opposite the clean side outlet (110), and the two filter elements (10, 40) are directly sealed to each other by the seal interface (80) in the filtration system (100).

2. The filtration system according to claim 1, wherein the seal interface (80) includes a seal surface (25) provided on the support tube (24) of the first filtration element (10) located on the opposite side of the clean outlet (110), and at least one seal element (60, 62, 64) disposed on the second filtration element (40) that seals the seal surface (25) in the axial and / or radial direction (72, 74).

3. The filtration system according to claim 1 or 2, wherein the seal interface (80) includes a seal element (60) disposed on a circumferentially extending projection (52) that protrudes axially (72) away from the cover (50) at the outer end face of the cover (50), and the seal element (60) seals radially (74) to the support tube (24) of the first filtration element (10).

4. The filtration system according to claim 1 or 2, wherein the sealing interface (80) is located on a circumferentially extending edge (51) of the cover (50) and includes a sealing element (62) that seals radially (74) to the support tube (24) of the first filtration element (10).

5. The filtration system according to claim 1 or 2, wherein the seal interface (80) includes a seal element (64) provided on the end face (46) of the second filtration element (40), and the seal element (64) seals in the axial direction (72) against the rim (26, 29) of the support tube (24) of the first filtration element (10) which protrudes radially (74) inward.

6. The filtration system according to claim 1, wherein the seal interface (80) includes a region (15) of the second end disk (18) of the first filter element (10) located on the opposite side of the clean outlet (110) in the axial direction (72), and at least one seal surface (45) provided on the second filter element (40).

7. The filtration system according to claim 6, wherein the second end disc (18) of the first filtration element (10) protrudes radially (74) inward beyond the filter material (11).

8. The filtration system according to claim 6 or 7, wherein the region (15) is located on the inner rim of the second end disc (18) of the first filtration element (10), the inner rim seals against a sealing surface (45) provided on the radially (74) outer circumferential surface of a circumferentially extending projection (52) located on the cover (50), and the projection protrudes away from the cover (50) in an axial direction (72).

9. The filtration system according to claim 8, wherein a web (114) provided on the housing (102) that protrudes in the axial direction (72) engages with a groove (17) of the second end disc (18).

10. The filtration system according to claim 6 or 7, wherein the region (15) of the second end disc (18) of the first filtration element (10) seals radially (74) with respect to a sealing surface (45) located inside a circumferentially extending projection (52) in the cover (50), the projection protrudes axially (72) away from the cover (50), and the projection (52) engages with a groove (19) of the end disc (18).

11. The filtration system according to claim 10, wherein the inner rim of the second end disc (18) of the first filtration element (10) is supported radially (74) by a web (118) provided on the housing (102) that protrudes axially (72) inward.

12. The filtration system according to claim 6 or 7, wherein the region (15) is located on the axially inward end face (58) of a radial projection (20) that extends circumferentially within the cross-section of the filter material (11) on the second end disc (18) of the first filtration element (10), and the radial projection (20) seals against a sealing surface (45) provided on the end face of the cover (50).

13. The filtration system according to claim 12, wherein the support tube (24) of the first filtration element (10) protrudes radially (74) inward and includes a circumferentially extending rim (23) embedded in the radial projection (20).

14. The filtration system according to any one of claims 1 to 13, wherein the end face (112) of the housing (102) is curved inward.

15. The filtration system according to any one of claims 1 to 14, wherein the end face (112) of the housing (102) has an opening that extends at least partially onto the second end face (46) of the second filtration element (40).

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