Annular filter element with radial inner engagement profile for angular positioning

Abstract

The invention relates to a ring-shaped filter element comprising a filter medium body in the form of a bellows having at least one radially inwardly directed fold which is spread apart and adjoins an open end disc. The open end disc has at least one recess, the recess and the spread-apart fold being arranged so as to overlap one another. The filter medium body is sealed at the axial end facing away from the open end disc by a closure end disc. When the ring-shaped filter element is used in a filter device, an engagement element engages into the spread-apart fold and / or into the recess. The engagement element can be formed on a filter housing or on a further ring-shaped filter element of the filter device. The angular position of the ring-shaped filter element is thus fixed relative to the filter housing or to the further ring-shaped filter element.

Description

[0001] This patent application claims priority to German patent application DE102023129022.3, which was filed with the German Patent and Trademark Office on October 23, 2023, the contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to an annular filter element for air filtration, comprising: - The filter media surrounding the interior, and - Open end discs and closed end discs, which seal the filter media body in the axial direction. Background Technology

[0003] For example, such annular filter elements are disclosed in US 2021 / 0069630 A1.

[0004] In air filtration, for example, for internal combustion engines or fuel cells, it is important to use a suitable annular filter element for the specific application. Furthermore, proper alignment of the annular filter element is often also crucial. For example, mass airflow sensors are often sensitive to changes in filter element alignment. This also applies when annular filter elements with basic rotational symmetry exhibit certain manufacturing-related deviations related to rotational symmetry, even when they are installed in different rotational positions.

[0005] US 2019 / 0308125 A1 discloses a circular filter element comprising a filter media body whose walls are permissible for radial flow of a fluid to be purified, wherein a circumferentially extending sealing carrier is arranged at or near an end face, the sealing carrier carrying a positioning element for form-fitting connection to an associated housing-side reverse positioning element. For this purpose, a radially outwardly opening cutout is provided in the open end plate.

[0006] EP 2 535 550 A2 discloses an annular filter element, particularly a filter device for a fresh air system in an internal combustion engine, comprising an annular filter body of folded web material. End folds adjacent to each other in the circumferential direction are directly or indirectly connected to form a connection region suitable for rotational alignment of the filter element. In the connection region, a radially outward-opening longitudinal groove may be formed, which is particularly easily felt from the outside and, for example, enables forced alignment. An end plate may include a radially outward-opening recess complementary to the radially outward-opening longitudinal groove. Alternatively, a radially inward-opening longitudinal groove may be provided in the connection region. The corresponding groove base of the longitudinal groove may be formed, for example, by end folds that contact each other. At the housing, an alignment profile is formed that interacts with the connection region when the annular filter element is inserted, so as to force the annular filter element into a predetermined rotational position within the housing.

[0007] The previously mentioned US 2021 / 0069630 A1 describes a filter element with a filter corrugation that extends along a longitudinal axis and surrounds an interior. The filter corrugation is formed of folded filter material arranged on a support tube. The filter corrugation can be designed as a circular element. End plates are arranged at a first end face and an opposite second end face of the filter element, sealing the filter corrugation at the edge of the end face, one of which is open and the other is closed. The filter corrugation includes external notches at both ends, the axial length of which is shorter than the length of the filter corrugation along the longitudinal axis. The notches are locally restricted and do not extend across the entire length of the folded corrugation. Preferably, the notches have the largest fold edge distance at the respective end plate and gradually narrow with increasing distance away from the end plate. The notches widen the distance between two adjacent folds, wherein the folds extend as a whole across the entire length of the folded corrugation. The notches allow the filter element to be correctly positioned within the housing.

[0008] When the outer folds expand, there is a certain risk that the filter media, especially at the edge of the folds that define the expansion, may be damaged during handling, such as when it is struck for cleaning purposes.

[0009] One object of the present invention is to protect the contours of the annular filter element used for alignment from damage. Summary of the Invention

[0010] This objective is achieved by the annular filter element according to claim 1 and the filter device according to claim 13. Furthermore, this objective is achieved by the application according to claims 20 and 21. Preferred embodiments are disclosed in the corresponding dependent claims and the specification.

[0011] According to the present invention, an annular filter element for air filtration is provided, particularly for filtering the intake air of a fuel cell. For application purposes, the annular filter element can be arranged within a filter housing. In particular, the annular filter element can be used as a cathode air filter for a fuel cell.

[0012] An annular filter element comprises a filter media body surrounding its interior. Therefore, the annular filter element is closed in the circumferential direction. Preferably, the annular filter element allows radial flow from the outside to the inside. Alternatively, radial flow from the inside to the outside can be provided.

[0013] The longitudinal axis of the filter media can extend through its interior. In other words, the filter media can be in a ring shape around the longitudinal axis. Directions such as radial or axial are specified relative to the longitudinal axis. The angular position of the ring-shaped filter element about the longitudinal axis can also be determined.

[0014] Furthermore, it is well known that annular filter elements have an open end plate and a closed end plate that sealably define the filter media body in the axial direction. The two end plates are arranged at opposite axial ends of the filter media body. The open end plate can additionally seal the annular filter element relative to the filter housing and / or other annular filter elements. The open end plate includes at least one central opening that opens from the inside to the outside at the axial end. In the installed state, a fluid outlet or fluid inlet can communicate with the interior through the central opening. At the other axial end, the closed end plate prevents inflow or outflow into the interior; thus preventing bypassing the filter media body.

[0015] The end plate can be molded or glued onto the filter media. The end plate can be made of, for example, polyurethane, especially polyurethane foam.

[0016] The closure endplate can be a single piece or a multi-piece configuration. A multi-piece closure endplate may include, for example, a closure member embedded in an annular body of the endplate.

[0017] The filter media body includes a pleated corrugated element, which, according to the invention, has at least one pleated enlargement at its inner wall surface. The pleated corrugated element or filter media body may, in particular, be formed of a star-shaped pleated filter media. The pleating angle and / or pleating distance (the distance measured in the circumferential direction along the radial inner edge of the pleating portion) in the pleated enlargement area at the inner wall surface of the annular filter element may be greater than the pleating angle and / or pleating distance of multiple pleats of the pleated corrugated element. Specifically, all pleats, except for the area of ​​the at least one pleated enlargement, may include the same pleating angle or pleating distance. In principle, the pleated enlargement at the inner wall surface abuts the open end plate.

[0018] The folded enlargement at least partially forms a reverse engagement element for engagement by the engagement element of the positioning device, for a particularly defined relative angular positioning of the annular filter element relative to the filter housing or other filter elements of the filter device. The folded enlargement creates space for engagement of the engagement element of the positioning device. Additionally, the partially present folded enlargement provides a defined angular position of the first annular filter element relative to the engagement element. The engagement element and the reverse engagement element can be matched relative to each other (i.e., they correspond to each other) such that deformation of these elements during installation is minimal or preferably unnecessary, but simultaneously minimal or preferably nonexistent rotational clearance. The former reduces the required force expenditure and avoids damage. The latter affects the defined rotational alignment of the annular filter element. The rotational clearance relative to the center position can reach, for example, a maximum of + / -5°, preferably a maximum of + / -3°, and particularly preferably a maximum of + / -1°.

[0019] Further according to the invention, the open end plate includes at least one notch aligned with the folded enlargement. When multiple folded enlargements are provided, one notch is aligned with one of the folded enlargements respectively. The notch and the folded enlargement overlap each other in the circumferential and radial directions. The notch may be arranged at the inner circumference of the open end plate. The notch in the end plate facilitates the insertion of a coupling element into the folded enlargement. The notch in the open end plate may also be part of a reverse coupling element engaged by the coupling element in the installed state.

[0020] Due to the inwardly positioned arrangement of the folded expansions and cutouts, the annular filter element is protected from mechanical damage when handled. In particular, there is no risk that the edges of the folded expansions, which define the annular filter element, may deform or even tear when struck.

[0021] The folded expansion section can extend across a portion of the height of the folded corrugated section. This is advantageous for the flow through the filter media.

[0022] Alternatively, the folded extension can extend across the entire height of the folded corrugated element. This simplifies the manufacturing of the annular filter element.

[0023] The filter media body may include a hollow cylindrical shape. In particular, the cross-section of an annular filter element or its filter media body may be annular. Such annular filter elements can be manufactured economically and offer excellent installation space utilization. In embodiments, the filter media body may have an elliptical or elongated elliptical cross-section. Alternatively or additionally, the filter media body may gradually narrow along its longitudinal axis. In other words, the filter media body may generally comprise a conical shape.

[0024] Folded coils can be installed on the outer surface of the filter media body. In other words, the ribs can be spirally wound around the outer side of the filter media body. In this way, the filter corrugated element can be additionally fixed and stabilized.

[0025] Multiple folded enlargements can be distributed around the inner circumference of the folded corrugated element, wherein the open end plate includes multiple cuts, each cut aligned with one of the folded enlargements. Due to the rotationally symmetrical arrangement of the cuts, the installation of the annular filter element can be simplified.

[0026] However, preferably, the folded expansions and cutouts are arranged in a non-rotationally symmetrical manner about the longitudinal axis. This creates a defined angular position for the annular filter element. This is advantageous for achieving a defined flow, for example, for the measurement accuracy of downstream components (e.g., mass airflow sensors). Furthermore, when multiple, and especially all, folded expansions are joined by connecting elements, the non-rotationally symmetrical arrangement effectively prevents the use of unsuitable annular filter elements.

[0027] The at least one cut in the open end plate may open radially inward. The cut and the center opening of the end plate are then directly connected to each other. The radially inward-opening cut at the edge may also be referred to as a protrusion of the center opening. When installing filter elements, the inward-opening cut facilitates the insertion of the connecting element.

[0028] Alternatively, the cutout of the open endplate can be closed radially inward. The cutout and the central opening of the endplate are then separated from each other radially by the material of the endplate. An axially projecting type of engagement element can protrude through the cutout closed at the edge side into the folded enlargement.

[0029] It can be specified that the cut gradually narrows and / or widens radially outward, and / or that at least one lateral edge of the cut may have at least one kink. When the joining element also has a corresponding profile, a suitable annular filter element can be forced to be used even when cuts exist at the corresponding same location on the open end plate in different types of annular filter elements.

[0030] An annular filter element may include a fluid-permeable central tube disposed on the inner wall surface of the filter media body and directly or indirectly fastened to the filter media body. The central tube supports the filter media body, particularly in cases where flow is radial from the outside to the inside. The central tube may be designed as a mesh with axial and circumferential struts.

[0031] Preferably, at least one support element may be formed at the central tube and extend radially outward into the folded enlargement. The support element of the central tube is part of the reverse engagement element of the annular filter element. In principle, the support element opens in a radially inward direction. The engagement element of the positioning device can then engage the support element radially outward. The support element preferably includes a radially outwardly narrowing cross section, particularly tapering in a pointed manner. The central tube with such a support element simplifies the manufacture of the folded enlargement at the inner circumference of the filter media body, as the support element widens the folded portion at its engagement when the folded corrugated element and the central tube are joined.

[0032] The support element and the central tube can be a single part. This further simplifies manufacturing.

[0033] A support section can be formed at the open end plate, particularly where the support section and the open end plate are integrally formed. The support section extends radially outward into the folded enlargement. The support section of the open end plate is part of the engaging element. The support section preferably includes a radially outwardly tapering cross section, particularly tapering in a pointed manner. In this embodiment, one or more folds can be widened during the molding of the annular filter element and can be secured in the unfolded configuration by the molded end plate. In this embodiment, a central tube for element fixation, particularly a central tube with a support element, can be additionally provided. Typically, a housing-fixed central tube is used in this embodiment.

[0034] The open end plate may include at least one continuously circumferentially extending seal for contact at the filter housing, particularly wherein the seal is formed as a sealing flange projecting in an axial direction. In the installed state, the seal separates the untreated side (typically radially outward) from the clean side (typically radially inward, including the interior of the filter media body). The seal may extend fully circumferentially around the opening of the open end plate, which is in fluid communication with the interior of the filter media body. Preferably, the seal is provided integrally with the end plate. The sealing flange may also be referred to as a sealing collar.

[0035] In another preferred embodiment, the seal is specified to be radially outward around the at least one cutout, preferably wherein the seal in the cutout region includes radially outwardly oriented protrusions. In other respects, the seal may be circular. Therefore, in the cutout region, the seal deviates from a circular shape. On the one hand, this ensures a seal on the end plate, for example, a seal relative to the filter housing and / or other annular filter elements. On the other hand, the seal profile may be specifically formed at the filter housing, corresponding to a seal with protruding protrusions. Thus, only annular filter elements with corresponding protruding seals can be installed. This ensures the use of suitable annular filter elements.

[0036] In an alternative embodiment, the at least one cut is specified to extend axially along the inner circumference of the seal. Specifically, the seal at the inner circumference may include at least one recess aligned with the cut. In other words, the recess at the inner circumference of the seal may form an extension of the cut. The cross-section of the seal can be reduced by the recess in the radial direction. Here, the seal profile at the filter housing may also correspond to a seal forming, for example, where the engaging element directly abuts the seal profile protrusion. Then, the annular filter element with the seal can only be installed if the recess (and therefore the reverse engaging element at the annular filter element) extends axially across the entire height of the seal. This ensures the use of a suitable annular filter element.

[0037] The scope of the invention also includes a filtration device comprising a filter housing having at least one fluid inlet and at least one fluid outlet, and further comprising an annular filter element arrangement structure disposed within the filter housing and separating the fluid inlet and the fluid outlet, wherein the annular filter element arrangement structure includes at least the first annular filter element according to the invention as described above. The filtration device is an air filtration device. (First) The annular filter element may be the only annular filter element in the annular filter element arrangement structure; alternatively, in addition to the first annular filter element, the annular filter element arrangement structure may include at least one or more additional annular filter elements, which may in particular be arranged radially inside or radially outside the first annular filter element. The additional annular filter elements provided may, as needed, be annular filter elements according to the invention or not according to the invention.

[0038] The filtration device includes a positioning device with at least one radially outwardly extending engaging element, wherein a folded enlargement at the inner wall surface of the filter media body of the first annular filter element at least partially forms a reverse engaging element, and wherein the engaging element engages the reverse engaging element. Preferably, a cut in the open end plate also at least partially forms a reverse engaging element. The engaging element may be arranged at the filter housing or at another annular filter element. The positioning device achieves a particularly defined relative angular positioning of the annular filter element relative to the filter housing or another annular filter element of the filtration device.

[0039] In a preferred embodiment, the filtration device includes a support tube fastened to the filter housing, particularly in a non-releasable manner, and releasably disposed within the filter media body of the first annular filter element, wherein the engaging element of the positioning device is disposed at the support tube. In this way, the (first) annular filter element can be aligned relative to the filter housing in its rotational position. Furthermore, the support tube centers the annular filter element within the filter housing and can radially support its filter media. For example, the support tube can be releasably or non-releasably locked to the filter housing, particularly in a defined angular position. Alternatively, the support tube can be screwed into the filter housing. The support tube is typically fluid-permeable. A fluid-permeable support tube can be designed as a mesh with axial and circumferential struts.

[0040] In a first further development of this embodiment, additional filter media bodies of another annular filter element in the annular filter element arrangement are indirectly or directly radially outwardly fastened to the support tube. This additional filter media body can be, for example, a filter nonwoven fabric that can be wound around the support tube. The at least one connecting element and the additional filter media body can be arranged sequentially in the axial direction at the support tube. The filter media body of the additional annular filter element can include an adsorbent, particularly activated carbon. Alternatively or additionally, the additional filter media bodies radially outwardly arranged at the support tube can be so-called secondary filter elements or safety filter elements.

[0041] In a further alternative development, the inner annular filter element of the annular filter element arrangement is disposed inside the support tube, and includes a second reverse engagement element on its outer wall surface, wherein the engagement element of the support tube radially outwardly engages the (first) reverse engagement element of the first annular filter element, and the engagement element of the support tube radially inwardly engages the second reverse engagement element of the inner annular filter element. The radially outwardly extending engagement element and the radially inwardly extending engagement element may be located at the same angular position. Alternatively or additionally, the radially outwardly extending engagement element and the radially inwardly extending engagement element may be integral. However, in embodiments, the radially outwardly extending engagement element and the radially inwardly extending engagement element may also be located at different angular positions and / or may be specifically implemented as separate from each other.

[0042] In this manner, two annular filter elements are aligned and fixed in their angular positions relative to each other by a support tube fixed to the housing. The defined angular positions of the two annular filter elements relative to the filter housing are additionally created when the support tube is tightened to the filter housing in the defined angular positions. The filter media body of the inner annular filter element may include folded corrugations. A second counter-engaging element of the inner annular filter element may be formed by a folded enlargement on the outer wall surface of its filter media body. The filter media body of the inner annular filter element may include an adsorbent, particularly activated carbon.

[0043] As an alternative to or supplement to the internal annular filter element, the annular filter element arrangement structure of the filtration device may include an external annular filter element having a filter media body, wherein the filter media body of the external annular filter element surrounds the interior, and wherein the first annular filter element is at least partially housed within the filter media body of the external annular filter element. The filter media body of the external annular filter element may include pleated corrugated elements. In this embodiment, the filter media body of the first annular filter element may include an adsorbent, particularly activated carbon.

[0044] The filter housing may include a housing positioning device for a specifically defined relative angular positioning of the outer annular filter element relative to the filter housing. The housing positioning device includes a housing engaging element that extends radially inward and engages a corresponding housing reverse engaging element of the outer annular filter element. In this way, the outer annular filter element is fixed in a defined angular position relative to the filter housing. The housing reverse engaging element of the outer annular filter element may have a folded enlargement formed on the outer wall surface of the outer annular filter element.

[0045] As an alternative to or supplement to the housing positioning device, the external annular filter element may include a fluid-permeable inner tube disposed on the inner wall surface of the filter media body of the external annular filter element and indirectly or directly fastened to the filter media body of the external annular filter element. Further engaging elements are disposed at the inner tube, particularly integrally formed with the inner tube, wherein these additional engaging elements extend radially inward and engage with additional counter-engaging elements on the outer wall surface of the filter media body of the first annular filter element. Thus, the two annular filter elements are aligned and fixed in their angular positions relative to each other by the inner tube of the external annular filter element. When the first annular filter element (e.g., a support tube fixed to the housing by the engaging elements of the housing with positioning devices) or the external annular filter element (e.g., by the housing positioning device) is aligned in a defined angular position at the filter housing, a defined angular position of both annular filter elements relative to the filter housing is simultaneously provided. The fluid-permeable inner tube may be designed as a mesh with axial and circumferential struts.

[0046] The filtration device may include a cyclone element arranged upstream of an annular filter element arrangement. In other words, the cyclone element is fluidly arranged between the fluid inlet and the annular filter element arrangement having at least one annular filter element. The cyclone element achieves pre-separation, particularly of coarse dust. This extends the service life of the annular filter arrangement.

[0047] The present invention also relates to the use of the aforementioned filtration device according to the present invention as a cathode air filter for a fuel cell.

[0048] The scope of the invention also includes fuel cells having an anode and a cathode, an electrolyte disposed between the anode and the cathode, and having the aforementioned filtration device according to the invention through which air can be supplied to the cathode.

[0049] Furthermore, the scope of the invention includes the use of the aforementioned annular filter element according to the invention in a filtration device having a filter housing, wherein a connecting element arranged at the filter housing engages the folded enlargement. The advantages of the annular filter element can be utilized in this application. Attached Figure Description

[0050] Further features and advantages of the invention are aided by the following detailed description of embodiments of the invention, the claims, and the accompanying drawings illustrating details according to the invention. In variations of the invention, the foregoing and further explained features may be implemented individually or in any convenient combination. Features illustrated in the accompanying drawings make the characteristics according to the invention more clearly visible. The drawings show: Figure 1 This is a schematic longitudinal section of a first embodiment of a filtration device according to the present invention, which has an annular filter element arrangement structure, the annular filter element arrangement structure including a first annular filter element according to the present invention and an inner annular filter element arranged inside the first annular filter element. Figure 2 yes Figure 1 A schematic longitudinal section of the first annular filter element of the filtration device; Figure 3 yes Figure 1 A schematic longitudinal section of the internal annular filter element of the filtration device; Figure 4 Is it through Figure 1 A schematic cross-section of a filtration device; Figure 5 yes Figure 4 Magnified details; Figure 6 yes Figure 1 Magnified details; Figure 7 This is a schematic cross-section of a second embodiment of a filtering device according to the invention, having an annular filter element arrangement structure including an inner annular filter element housed within an outer annular filter element according to the invention. The schematic cross-section extends in a stepped manner so that it can be seen even if the positioning device at the inner annular filter element and the additional positioning device between the annular filter elements and the housing positioning device at the outer annular filter element are arranged at different axial ends. Figure 8 yes Figure 7 Magnified details; Figure 9 yes Figure 7 Schematic longitudinal section detail of the filtration device in the positioning device area at the open end plate of the internal annular filter element; Figure 10 yes Figure 7 The details of the filter device in a schematic longitudinal section in the closed end plate area, with additional positioning devices between the two annular filter elements and the housing positioning device; Figure 11 yes Figure 7 A schematic perspective view of the internal annular filter element of the filtration device according to the present invention; Figure 12 This is a schematic longitudinal section of a third embodiment of a filtration device according to the invention, which has an annular filter element arrangement structure including an inner annular filter element housed in an outer annular filter element according to the invention. Figure 13 yes Figure 12 A schematic perspective view of the internal annular filter element of the filtration device; Figure 14 This is a fourth embodiment of the filter device according to the invention, which has an annular filter element arrangement structure, the annular filter element arrangement structure including an inner annular filter element housed in an outer annular filter element according to the invention, the schematic cross section extending in a stepped manner, so that the positioning device at the inner annular filter element and the housing positioning device at the outer annular filter element can be seen even if they are arranged at different axial ends. Figure 15 This is a schematic longitudinal section of a fifth embodiment of a filtration device according to the present invention, which has an annular filter element arrangement structure, the annular filter element arrangement structure including an inner annular filter element according to the present invention housed in an outer annular filter element according to the present invention. Figure 16 yes Figure 15 A schematic longitudinal section of a filter device, wherein the cross-sectional plane is parallel to... Figure 15 Compared to a 90° rotation; Figure 17 This is a schematic longitudinal section of a sixth embodiment of a filtration device according to the present invention, which has an annular filter element arrangement structure, the annular filter element arrangement structure including an inner annular filter element according to the present invention housed in an outer annular filter element. Figure 18 yes Figure 17 A schematic longitudinal section of a filter device, wherein the cross-sectional plane is parallel to... Figure 15 Compared to a 90° rotation; Figure 19 This is a schematic perspective view of a seventh embodiment of the filtering device according to the present invention; Figure 20 yes Figure 19 A schematic cross-sectional view of a filtration device, in which an annular filter element according to the invention can be seen arranged in a filter housing; Figure 21 yes Figure 20 A schematic perspective view of the annular filter element of the filtration device; Figure 22 This is a schematic diagram of a cross-section of an annular filter element according to the present invention, which has multiple folded enlargements in an arrangement structure that does not have rotational symmetry; Figure 23 This is a schematic illustration of an open end plate for an annular filter element according to the present invention, wherein the end plate includes a radially outwardly widened cutout. Figure 24 This is a schematic illustration of an open end plate for an annular filter element according to the present invention, wherein the end plate includes a radially outwardly widened cutout. Figure 25 This is a schematic perspective view of another annular filter element according to the invention, wherein the open end plate includes a support section for inward positioning of a folded enlargement. Figure 26 This is a schematic cross-section of an eighth embodiment of the annular filter arrangement structure according to the present invention, which has an annular filter element according to the present invention, wherein a support tube engaging the annular filter element radially outward supports another annular filter element. Figure 27 yes Figure 26 A schematic perspective view of the support tube of the filter device; Figure 28 This is a schematic diagram illustrating the use of the filtration device according to the invention as a cathode air filter for a fuel cell according to the invention. Detailed Implementation

[0051] Figure 1A filter device 10.1 is shown, here in the form of an air filter. The filter housing 12 of the filter device 10.1 includes a housing top 14 and a housing bottom 16, which are releasably connected to each other. An annular filter element arrangement 20 is housed within the filter housing 12. The annular filter element arrangement 20 separates a fluid inlet 22 for unfiltered air from a fluid outlet 24 for filtered air. The fluid inlet 22 and fluid outlet 24 are formed here, exemplarily, at the housing top 14.

[0052] The annular filter element arrangement structure 20 includes a first annular filter element 26 (here, the outer annular filter element, also see...) Figure 2 ) and the second annular filter element 28 (here referring to the internal annular filter element, also see Figure 3 These two annular filter elements can be flowed through radially from the outside to the inside. Each of the two annular filter elements 26, 28 includes a (first or second) filter medium body 30 or 32, which surrounds a corresponding interior 34 or 36. The filter medium bodies 30 and 32 are specifically implemented as hollow cylinders with an annular cross-section. The outer wall surface of the first filter medium body 30 is identified by reference numeral 38, and the inner wall surface of the first filter medium body 30 is identified by reference numeral 40. The outer wall surface of the second filter medium body 32 is identified by reference numeral 42, and the inner wall surface of the second filter medium body 32 is identified by reference numeral 44.

[0053] Compare Figure 1 and Figure 4 In the installed state, the two annular filter elements 26 and 28 are arranged coaxially with each other. The extensions of the filter media bodies 30 and 32 pass through the longitudinal axes 46a and 46b of the corresponding interiors 34 and 36 and coincide with the common longitudinal axis 46.

[0054] The two filter media bodies 30 and 32 are respectively formed as folded corrugated elements here, which are obtained through the star-shaped folds of the flat filter media. Figure 4 The diagram illustrates some of the corresponding folds. The filter medium, particularly the internal annular filter element 28 downstream along the flow direction, may contain an adsorbent, such as activated carbon, to remove harmful gases from the airflow to be filtered.

[0055] The axial end faces of the two filter media bodies 30 and 32 are sealed by end plates 48, 50, 52, and 54, respectively. Currently, closed end plates 50 and 54 are provided at one end. At the other end, open end plates 48 and 52 are provided to allow the inner annular filter element 28 to be inserted into the outer annular filter element 26, and to allow filtered air to exit through the fluid outlet 24. In the installed state, the open end plates 48 and 52 are in sealing contact with the top 14 of the housing. The seal 55 at the open end plate 48 of the first annular filter element 26 is specifically implemented with a sealing flange 122 protruding in the axial direction.

[0056] In the filter device 10.1, a support tube 96 is provided, which is attached to the filter housing 12 and extends between the two annular filter elements 26 and 28. Figure 1 and 4 In the context of this invention, the region between the inner wall surface 40 of the first filter medium 30 and the outer wall surface 42 of the filter medium 32 is also referred to as the interface region 58. For example, the support tube 96 can be locked in a fixed angular position at the top 14 of the housing, in particular... Figure 6 This angular position can be defined by the engagement of the axial protrusion fixed to the housing in the end face recess of the support tube (not shown in detail). For installation, the two annular filter elements 26, 28 can be pushed onto or inserted into the support tube 96, and for removal, they can be pulled off the support tube 96.

[0057] The positioning device 60 functions between the first and second annular filter elements 26, 28, and holds the two annular filter elements 26, 28 in a defined angular position (rotational position) about the longitudinal axis 46. Figure 1 and 4 The positioning device 60 includes a coupling element 62 arranged in the interface region 58 between the two annular filter elements 26, 28, and also corresponds to... Figure 5 and Figure 6 .

[0058] On one hand, the engaging element 62 protrudes radially outward into the reverse engaging element 98 of the first annular filter element 26. Thus, the angular position of the first annular filter element 26 about the longitudinal axis 46 relative to the filter housing 12 is fixed. On the other hand, the engaging element 62 protrudes radially inward into the (second) reverse engaging element 64 of the second annular filter element 28. Thus, the angular position of the second annular filter element 28 about the longitudinal axis 46 relative to the filter housing 12 is fixed. Because the engaging element 62 of the support tube 96 engages the reverse engaging elements 64 and 98 of the two filter elements 26 and 28, the filter elements 26 and 28 are also fixed relative to each other at a defined angular position about the longitudinal axis 46; this also applies even if the support tube is rotatably held at the filter housing 12.

[0059] The reverse engagement element 98 of the first annular filter element 26 includes a cutout 100 formed radially inward at the open end plate 48, also in contrast to Figure 2 Additionally, the reverse engagement element 98 includes a folded enlargement 102 aligned with a cutout 100 at the inner wall surface 40 of the first filter media body 30. Here, the folded enlargement 88 does not extend across the entire axial length of the first filter media body 30, but is limited to less than one-third of its total length. In an embodiment not shown in detail, the folded enlargement may also extend across the entire length of the first filter media body 30 from the open end plate 48 to the closed end plate 50.

[0060] The cut 100 opens radially inward at this location. In other words, the cut 100 immediately enters the central opening 101 of the open end plate 48. Therefore, the cut 100 can also be considered as a protrusion in the edge of the central opening 101. The central opening 101 and the cut 100 are surrounded on the outside by a sealing flange 122.

[0061] In the region of the folded enlargement 102, the fold distance between the radial inner fold edges 104 of the first filter medium body 30, measured in the circumferential direction, is enlarged compared to the fold distance between adjacent inner fold edges 104, especially in contrast. Figure 5 Here, the fold enlargement 102 is limited to a single inwardly opening fold. Compared to the adjacent fold, the fold angle 106 is also enlarged due to the fold enlargement 102.

[0062] The reverse engagement element 64 of the internal annular filter element 28 is formed by a cutout 65' in the open end plate 52 (see special reference). Figure 3 ) and the folded enlargement 66 is formed at the outer wall surface 42 of the star-shaped folded filter media 32 (special contrast) Figure 5 Special comparison Figure 3 The cut 65 and the folded enlargement 66 are aligned with each other.

[0063] In the region of the folded enlargement 66, the fold distance measured circumferentially between the radially outer fold edges 68 of the second filter media body 32 is increased compared to the fold distance between adjacent outer fold edges 68. Here, the folded enlargement 66 is limited to a single outwardly opening fold. The fold angle 70 is also increased due to the folded enlargement 66 compared to adjacent folds. Currently, the folded enlargement 66 does not extend across the entire axial length of the second filter media body 32, but is limited to less than one-third of its entire length. In an embodiment not shown in detail, the folded enlargement can extend across the entire length of the second filter media body 32 from the open end plate 52 to the closed end plate 54.

[0064] For example, the central tube 76, which can be fixedly arranged at the housing, can be locked to the top 14 of the housing, and the second annular filter element 28 can be radially supported inward at its inner wall surface 44, in contrast. Figure 1 .

[0065] Figure 7 The second filter device 10.2 is shown. Figure 7 The filter device 10.2 corresponds in many respects to Figures 1 to 6 The filter device 10.1 shown above is similar to the one described above. The main differences will be explained below; otherwise, refer to the description above.

[0066] The filtration device 10.2 includes an annular filter element arrangement 20 having a first annular filter element (here, an inner annular filter element) 28' and an outer annular filter element 26'. The annular filter elements 26' and 28' are arranged coaxially with a common longitudinal axis 46 within the filter housing 12. The filter media body 32 of the first inner annular filter element 28' is surrounded on the outside by the filter media body 30 of the outer annular filter element 26'; in other words, the filter media body 32 is housed within the interior 34 of the filter media body 30.

[0067] Here, the filter media bodies 30 and 32 of the two annular filter elements 26' and 28' are also formed by star-shaped folded filter corrugations. The annular filter elements 28' and 26' of the annular filter element arrangement structure 20 can be radially flowed sequentially from the outside to the inside. The filter media body 30 of the outer annular filter element 26' is therefore also referred to as the first filter media body; the filter media body 32 of the first inner annular filter element 28 is correspondingly referred to as the second filter media body.

[0068] In the filter device 10.2, a positioning device 108 is provided, which aligns the first internal annular filter element 28' relative to the filter housing 12 about the longitudinal axis 46 in a defined angular position. The positioning device 108 includes an engaging element 110, which is also compared to... Figure 8 and 9The engaging element 110 is formed as a radially outward-pointing protrusion at the support tube 111 fixed to the housing. The support tube 111 can be locked in a defined angular position at the top 14 of the housing.

[0069] The engaging element 110 engages the reverse engaging element 112 at the second annular filter element 28'. The reverse engaging element 112 includes a folded enlargement 114 located on the inner wall surface 44 of the second filter media body 32 (see specific contrast). Figure 8 ) and a radially inward cut 116 located at its open end plate 52, for comparison Figure 11 Here, the folded enlargement 88 does not extend across the entire axial length of the first filter medium body 30, but is limited to less than one-quarter of the total length, in contrast to... Figure 9 .

[0070] In the region of the enlarged fold portion 114, the fold distance between the radial inner fold edges 118 of the second filter medium body 32, measured in the circumferential direction, is enlarged compared to the fold distance between adjacent inner fold edges 118. Figure 8 Here, the enlarged fold portion 114 is limited to a single inwardly opening fold portion. Compared to the adjacent fold portion, the fold angle 120 is also enlarged due to the enlarged fold portion 114.

[0071] In the filter device 10.2, an additional positioning device 60' is formed between the two annular filter elements 26' and 28'. This positioning device 60' has an additional engaging element 62', which is a radially inwardly pointing protrusion located at the inner tube 56, which is fixedly connected to the outer annular filter element 26. (See also...) Figure 10 The additional engaging element 62' engages with the additional reverse engaging element 64' at the first internal annular filter element 28', which is also formed here by the folded enlargement 66 at the outer wall surface 42 of the second filter medium body 32 (also in contrast in this respect). Figure 5 Additionally, another reverse engagement element 64' includes a cutout 65 that aligns with the folded enlargement 66 at the closed end plate 54, for comparison. Figure 11 The additional reverse engagement element 64' can be shifted, for example, by 90 degrees in the circumferential direction relative to the reverse engagement element 112, similarly to... Figure 7 .

[0072] Comparison Figure 10In the filter device 10.2, the engaging element 62' includes a recess 72 on its end face (in the region of the end plate 50). The originally closed end plate 50 is also perforated in the region of the recess 72. However, the additional engaging element 62' is fluid-tightly closed and tightly fitted into the end plate 54, such that the outer annular filter element 26' remains sealed at its bottom end.

[0073] The axial protrusion 74 fixed to the housing engages with the recess 72 of another engaging element 62', which is specifically implemented here as being integral with the bottom 16 of the housing. In other words, the axial protrusion 74 passes through the end plate 54 and enters the hollow engaging element 62'.

[0074] The defined angular position of the outer annular filter element 26' relative to the filter housing 12 is achieved by engagement of the axial protrusion 74 in the recess 72 of the additional engagement element 62'. The engagement of the additional engagement element 62' in the additional reverse engagement element 64' of the first inner annular filter element 28' also results in the first annular filter element 28' (indirectly via the outer annular filter element 26') being angularly positioned relative to the filter housing 12. The additional engagement element 62', fixedly connected to the outer annular filter element 26', thus affects the angular positioning of the two annular filter elements 26', 28' of the annular filter element arrangement 20 relative to each other, and the angular positioning of the annular filter element arrangement 20 as a whole relative to the filter housing 12.

[0075] In the filter device 10.2, a housing positioning device 82 is also provided, which aligns the outer annular filter element 26' with respect to the filter housing 12 about the longitudinal axis 46 at a defined angular position. Figure 7 and 10 The housing positioning device 82 includes a housing engagement element 84 in the form of a wedge-shaped rib, which may be integral with the housing bottom 16, for example. The housing engagement element 84 gradually narrows towards the top and protrudes less radially inward in the upward direction. In the axial direction, the height of the first housing engagement element 84 is limited to less than one-quarter of the length of the first filter media body 30.

[0076] The housing engagement element 84 engages the housing reverse engagement element 86 at the first annular filter element 26'. (See comparison) Figure 7 and Figure 10 The housing reverse engagement element 86 includes a folded enlargement 88 on the outer wall surface 38 of the first filter media body 30 and a cutout 90 in its closed end plate 50. Here, the folded enlargement 88 does not extend across the entire axial length of the first filter media body 30, but is limited to less than one-third of its total length.

[0077] In the region of the folded enlargement 88, the fold distance between the radially outer fold edges 92 of the first filter media body 30, measured in the circumferential direction, is increased compared to the fold distance between adjacent outer filter fold edges 92. Here, the folded enlargement 88 is limited to a single outwardly opening fold. Compared to adjacent folds, the fold angle 94 is also increased due to the folded enlargement 88.

[0078] Figure 12 The third filter device 10.3 is shown. Figure 12 The filter device 10.3 corresponds in many respects to Figures 7 to 11 The filter device 10.2 shown above is similar to the one described above. The main differences will be explained below; otherwise, refer to the description above.

[0079] Similar to filter device 10.2, filter device 10.3 includes a positioning device 108 that aligns the first internal annular filter element 28' relative to the filter housing 12 about the longitudinal axis 46 in a defined angular position, wherein the engaging element 110 of the housing-fixed support tube 111 engages a reverse engaging element 112, wherein the reverse engaging element 112 is formed by a cutout 116 at the inner circumference of the end plate 52 and an adjacent folded enlargement 114 (in Figure 12 In the figure, the positioning device 108 is in front of the plane of the drawing and is therefore not visible, in contrast to this. Figure 9 Similarly, as in filter device 10.2, filter device 10.3 is provided with a housing positioning device 82 that positions the outer annular filter element 26' at an angle relative to the filter housing 12, wherein the housing engaging element 84 engages the housing reverse engaging element 86, wherein the housing reverse engaging element 86 is formed by a cutout 90 at the outer circumference of the end plate 50 and an adjacent folded enlargement 88.

[0080] In contrast to filter device 10.2, in filter device 10.3, an additional positioning device 60' is arranged in the region of the open end plate 48 of the first inner annular filter element 28'. In the illustrated embodiment, the additional engagement element 62' of the additional positioning device 60' takes the form of a radially inwardly pointing protrusion at the support tube 96 fixed to the housing. Alternatively, the additional engagement element 62' may be provided at the inner tube fastened to the outer annular filter element 26' (not shown in detail, but for comparison in this respect) Figure 9 and 10 The additional connecting element 62' is radially inwardly connected to another reverse connecting element 64' at the first inner annular filter element 28', and the reverse connecting element 64' here also has a folded enlargement 66 formed at the outer wall surface 42 of the second filter medium body 32 (also in contrast in this respect). Figure 5Additionally, the other engaging element 64' includes a cutout 65' aligned with the folded enlargement 66 at the open end plate 52, in contrast. Figure 13 The additional reverse engagement element 64' is shifted, for example, by 90° in the circumferential direction relative to the reverse engagement element 112.

[0081] The annular filter element 28' includes a seal 55 at the open end plate 52, which is in the form of an axially projecting sealing flange 122. The sealing flange 122 surrounds a central opening 123 on its outer side, the central opening 123 including an inward cutout 116 opening toward the central opening 123. The sealing flange 122 extends radially inward beyond the outward cutout 65'. The seal 55 includes radially inward recesses 124 or radially outward protrusions 126 in the regions of cutouts 65' and 116. In this respect, the originally circular sealing flange 122 deviates from a circular shape in these regions.

[0082] Figure 14 The fourth filter device 10.4 is shown. Figure 14 The filter device 10.4 corresponds in many respects to Figures 7 to 11 The filter device 10.2 shown above is similar to the one described above. The main differences will be explained below; otherwise, refer to the description above.

[0083] Similar to filter device 10.2, filter device 10.4 includes a positioning device 108 that aligns the first inner annular filter element 28' about the longitudinal axis 46 relative to filter housing 12 in a defined angular position, wherein engaging element 110 engages reverse engaging element 112, which is formed by a cutout 116 at the inner circumference of end plate 52 and an adjacent folded enlargement 114. The support tube 111, where engaging element 110 is formed, can be locked to the top 14 of housing in the defined angular position, in contrast to... Figure 9 .

[0084] Similarly, in filter device 10.2, a housing positioning device 82 is provided in filter device 10.4, which positions the outer annular filter element 26' at an angle relative to the filter housing 12. This is because the housing engaging element 84 engages the housing reverse engaging element 86, wherein the housing reverse engaging element 84 is formed by a cutout 90 at the outer circumference of the end plate 50 and an adjacent folded enlargement 88, which is also consistent in this respect. Figure 7 and 10 .

[0085] The inner tube 56 of the outer annular filter element 26' radially supports its filter media body 30. In the filter device 10.4, the inner tube 56 does not participate in the angular positioning of the annular filter elements 26' and 28'.

[0086] Figure 15 and 16 The fifth filter device 10.5 is shown. Figure 15 and 16 The filter device 10.5 corresponds in many respects to Figures 1 to 6 The filter device 10.1 shown above is similar to the one described above. The differences will be explained primarily below; otherwise, refer to the description above.

[0087] In the filter device 10.5, a positioning device 60 is also provided, which acts between the two coaxial annular filter elements 26 and 28', for comparison. Figure 15 The engaging element 62, formed at the support tube 96 where the housing is fixed, radially and outwardly engages with the corresponding reverse engaging element 98 at the open end plate 48 of the outer annular filter element 26. The reverse engaging element 98 is formed by an inwardly folded enlargement 102 at the star-shaped folded filter media body 30 and a cutout 100 aligned therewith at the inner circumference of the end plate 48, which is also consistent with... Figure 2 and 5 Furthermore, the engaging element 62 engages radially inward at the open end plate 52 of the second annular filter element 28' with the corresponding reverse engaging element 64, which is also consistent with this aspect. Figure 3 and 5 .

[0088] Furthermore, the filter device 10.5 includes a (second) positioning device 108, see [link to relevant documentation]. Figure 16 Similar to that in filter device 10.2, the engaging element 110 formed at the support tube 111 attached to the top of the housing 16 engages radially outward with a corresponding radially inwardly opening reverse engaging element 112 in the region of the upper end plate 52 of the inner annular filter element 28'; in this respect, refer to the description above and Figure 7 , 8 And 9. The second annular filter element 28' of the filter device 10.5 corresponds to Figure 13 The annular filter element 28' shown and described above.

[0089] In addition, the filter device 10.5 includes a housing positioning device 82, compared to... Figure 16 As in filter devices 10.2, 10.3, and 10.4, a housing engagement element 84 formed at the bottom 16 of the housing engages radially inwardly with a corresponding radially outwardly opening housing reverse engagement element 86 in the region of the closed end plate 50 of the first annular filter element 26; in this respect, refer to the description above and Figure 7 and 10 .

[0090] Figure 17 and 18 The sixth filter device 10.6 is shown, which in many respects corresponds to Figure 7 The filter device 10.2. The differences will be explained in detail below; for other aspects, refer to the description above.

[0091] Comparison Figure 18 The filter device 10.6 includes a positioning device 108. As in the filter device 10.2, a connecting element 110, arranged at the top 14 of the housing and formed at the support tube 111 fastened to the top 16 of the housing, radially outwardly engages a corresponding radially inwardly opening housing reverse connecting element 112 in the region of the open end plate 52 of the inner annular filter element 28'; in this respect, refer to the description above and Figure 7 , 8 And 9. The annular filter element 28' of the filter device 10.6 corresponds to Figure 11 The annular filter element 28' shown and described above.

[0092] An additional positioning device 60' between the inner annular filter element 28' and the outer annular filter element 26' is formed by a connecting element 62', which is in the form of a radially inwardly pointing protrusion at the inner tube 56. The inner tube 56 is fixedly connected to the outer annular filter element 26'. Figure 17 The engaging element 62' engages with the reverse engaging element 64' at the inner annular filter element 28', which is also formed here by the folded enlargement 66 at the outer wall surface 42 of the second filter medium body 32 (see also the comparison in this respect). Figure 5 At the engaging element 62', a radially outwardly pointing protrusion is also formed, which engages the folded enlargement 102 on the inner wall surface 40 of the first filter media body 30. The engaging element 62' is provided with two end face recesses 72, one of which faces either an inwardly protruding opening away from the inner tube 56 or an outwardly protruding opening. Each recess 72 is engaged by an axial protrusion 74 of the filter housing 12. Here, the axial protrusion 74 is integrally formed with the bottom 16 of the housing.

[0093] Additionally, the filter device 10.6 includes a housing positioning device 82, in contrast. Figure 18 As in filter device 10.2, a first housing engagement element 84 formed at the bottom 16 of the housing engages radially inwardly with a corresponding radially outwardly opening housing reverse engagement element 86 in the region of the closed end plate 50 of the first annular filter element 26'; in this respect, refer to the description above and Figure 7 and 10 .

[0094] Figure 19The filter housing 12 of the seventh filtration device 10.7 is shown. The filter housing 12 includes a fluid inlet 22 and a fluid outlet 24. An annular filter element 128 is housed within the filter housing 12, through which flow can pass radially from the outside to the inside. This annular filter element 128 represents the only annular filter element in the annular filtration arrangement 20, in contrast. Figure 20 See also Figure 19 A cyclone element is arranged upstream of the fluid in the annular filter element 128. This cyclone element is capable of providing pre-separation, particularly pre-separation of coarse dust. The cyclone element includes at least one dust discharge valve 130.

[0095] The filter media body 132 of the annular filter element 128 is designed as a pleated corrugated element surrounding the interior 133, in particular... Figure 20 At the outer wall surface 134, the filter media 132 is stabilized by spirally wound ribs 136, as in the control. Figure 21 Similarly, compare... Figure 20 A central tube 140 is arranged at position 138 on the inner wall surface, and this central tube 140 is formed here by axial struts and circumferential struts. (Comparison) Figure 20 The central tube 140 is embedded in the open end plate 142 at one end. At the other end, the central tube 40 is embedded in the closed end plate 144.

[0096] The filter media body 132 has a plurality of folded expansions 146 provided on its inner wall surface 138. The central tube 140 includes a support element 148 for each folded expansion 146, which radially outwardly engages the corresponding folded expansion 146. The support element 148 is specifically implemented here as a protrusion integrally formed in the central tube 140 and extends radially outward in a pointed manner, and is integrally formed with the central tube 140.

[0097] In the illustrated embodiment, the folded enlargement 146 and the cutouts 154 are evenly distributed along the inner circumference of the filter media body 132. Alternatively, the folded enlargement 146 and the cutouts of the open end plate 142 can be distributed in a pattern that is not rotationally symmetrical about the longitudinal axis 149 of the annular filter element 128, in contrast... Figure 22 .

[0098] For angular positioning of the annular filter element 128 relative to the filter housing 12, the positioning device 150 includes a connecting element 152 at the filter housing 12, which is axially protruding, in contrast to Figure 20The engaging element 152 engages one of the folded enlargements 146. To enable engagement of the axially extending engaging element 152, the open end plate 142 has a plurality of cuts 154 on its inner circumference, wherein a corresponding cut 154 is aligned with a folded enlargement 146. Figure 21 In this case, the cut 154 also extends at the inner circumference of the sealing flange 122, which protrudes axially away from the end plate 42 and forms a circumferential seal 55. A corresponding folded enlargement 146 with a corresponding support element 148 and a corresponding cut 154 forms a reverse engagement element 156 for engaging element 152.

[0099] In the annular filter element 128, the slit 154 in the open end plate 142 gradually narrows radially outward, especially in comparison. Figure 21 As an alternative, at least one cut 154 in the end plate 142 may widen radially outward, compared to Figure 23 It is also possible that at least one cut 154 in the end plate 142 includes at least one knot 158 ​​in at least one lateral edge 160, compared to Figure 24 The connecting element 152 thus typically includes a corresponding cross-section (not shown in detail). These configurations of cutouts and connecting elements are also conceivable in the aforementioned annular filter elements 26, 26', 28, 28'.

[0100] Figure 25 An additional annular filter element 162 is shown, which in many respects corresponds to Figure 21 The annular filter element 128. Therefore, in the following text, only the differences will be explained; otherwise, refer to the description above. The annular filter element 162 is formed on the inner wall surface 138 without a central tube. In other words, the inner folded edges of the filter media body 132, specifically implemented as a filter corrugated element, can be exposed on the inner wall surface 138. The annular filter element 162 can be stabilized on its inner wall surface 138 by at least one internally helically wound rib, which in particular also maintains the shape of the folded enlargement 146, such that adjacent inner folded edges are positioned relative to each other at a predetermined enlargement distance 163. In an embodiment, the annular filter element 162 includes a plurality of internally helically wound ribs spaced apart along a longitudinal axis.

[0101] Figure 26 The eighth filter device 10.8 is shown. It essentially corresponds to... Figure 19 The filter housing 12 shown contains an annular filter element, for example... Figure 21 The annular filter element 128 shown above. A support tube 164 engages with the interior 133 of the annular filter element 128, the support tube 164 in... Figure 27Shown separately, axial and circumferential struts are formed here. The support tube 164 includes a threaded section 166 at its axial end, by means of which the support tube 164 is screwed into a corresponding reverse thread of the filter housing 12. Furthermore, the support tube 164 includes at least one engaging element 168, which is formed here by a protrusion with a triangular cross-section. Currently, six engaging elements 168 are distributed around the circumference. In the illustrated embodiment, the engaging elements 168 are arranged between the threaded section 166 of the support tube 164 and the mesh-shaped tubular body 170. (See figure) Figure 26 With the filter device 10.8 installed, each engaging element 168 engages a reverse engaging element 156 of the annular filter element 128. In this way, the positioning device 172 formed by the engaging elements 168 and the reverse engaging elements 156 secures the annular filter element 128 in one of several (six in this case) possible angular positions within the filter housing 12.

[0102] Another annular filter element 174 is arranged radially outward at the tubular body 170, which... Figure 26 The annular filter element 174 is specifically implemented with an additional filter media body 176, here in the form of a filter nonwoven fabric, wherein the filter media body 176 is wound around the tubular body 170. The additional filter media body 176 is radially accommodated between the support tube 164 and the filter media body 132 of the annular filter element 128. The two annular filter elements 128 and 174 of the annular filter element arrangement structure 20 are arranged coaxially with a common longitudinal axis 46.

[0103] Figure 28 A fuel cell 186 is shown. The fuel cell 186 includes an anode 188, a cathode 190, and an electrolyte 192 disposed between them. The anode 188 and cathode 190 are respectively adjacent to a gas diffusion layer 193. The anode 188 and cathode 190 can be housed between transverse portions 194 and 196 of a bipolar plate 198. Hydrogen gas can be supplied to the anode 188 from a hydrogen inlet 200 through the transverse portion 194 of the bipolar plate 198. Oxygen or oxygen-containing air can be supplied to the cathode 190 from an air inlet 202 through the transverse portion 196 of the bipolar plate 198. A filter device 10, such as one of the filter devices 10.1 to 10.8 described above, is provided between the air inlet 202 and the cathode 188, having an annular filter element arrangement structure 20 disposed in a filter housing 12. The filter device 10 thus functions as a cathode filter. Water produced in the fuel cell 186 can be discharged through an outlet 204. The electrical connections of the fuel cell 186 are not shown in detail.

[0104] In summary, the present invention relates to an annular filter element having a filter media body in the form of a folded corrugated element, the filter media body including at least one radially inwardly folded enlargement abutting an open end plate. The open end plate includes at least one slit. The slit and the folded enlargement are arranged to overlap each other. At an axial end away from the open end plate, the filter media body is sealed by a closed end plate. When the annular filter element is used in a filtration device, a coupling element engages the folded enlargement and / or the slit. The coupling element may be formed at the filter housing of the filtration device or at another annular filter element. Therefore, the angular position of the annular filter element relative to the filter housing or another annular filter element is fixed.

[0105] List of reference numerals Filter devices 10.1; 10.2; 10.3; 10.4; 10.5; 10.6; 10.7; 10.8; 10 Filter housing 12 Top of the casing 14 16 at the bottom of the shell Annular filter element arrangement structure 20 Fluid inlet 22 Fluid outlet 24 First external annular filter element 26 External annular filter element 26' Internal annular filter element 28 First internal annular filter element 28' External annular filter element 26 / 26' filter media body 30 Internal annular filter element 28 / 28' filter media body 32 External annular filter element 26 / 26' internal 34 Internal annular filter element 28 / 28' internal 36 Surface 38 of the outer wall of the filter media 30 The inner wall surface 40 of the filter media body 30 42 of the outer wall surface of the filter media body 32 The inner wall surface 44 of the filter media body 32 The longitudinal axis 46a of the annular filter element 26 / 26' The longitudinal axis 46b of the annular filter element 28 / 28' Common longitudinal axis 46 48 open end plate of annular filter element 26 / 26' 50 closed end plate of 26 / 26' annular filter element Open end plate 52 of annular filter element 28 / 28' 54 closed end plate of 28 / 28' annular filter element Seal 55 at 48 of the open end plate The inner tube 56 of the annular filter element 26' Interface area 58 Positioning device 60 Another positioning device 60' Connecting element 62 Additional coupling element 62' Reverse coupling element 64 of annular filter element 28 The additional reverse engagement element 64' of the annular filter element 28' Radial outward cut 65 in end plate 54 Radial outward cut 65' in end plate 52 The folded enlargement 66 at the outer wall surface 42 of the second filter media body 32 The radial outer fold edge 68 of the second filter media 32 Folding angle 70 Recess 72 Axial protrusion 74 at filter housing 12 Central tube 76 Housing positioning device 82 Housing engagement element 84 Housing reverse engagement element 86 The folded enlargement 88 at the outer wall surface 38 of the filter media body 30 Radial outward cut 90 in end plate 50 Radial outer fold edge 92 of filter media body 30 Folding angle 94 96 Support tubes for fixed shell Reverse coupling element 98 of annular filter element 26 100 radial inward cuts in end plate 48 The center opening of the open end plate 48 is 101. The folded enlargement 102 at the inner wall surface 40 of the filter media body 30 The radially inner fold edge 104 of the first filter medium 30 Folding angle 106 Positioning device 108 Connecting element 110 Support tube 111 for fixed shell Reverse coupling element 112 at the annular filter element 28' The folded enlargement 114 at the inner wall surface 44 of the filter media body 32 Radial inward cut 116 in end plate 52 Radial inner fold edge 118 of filter media body 32 Folding angle 120 Sealing flange 122 The center opening of the open end plate 52 is 123. Depression 124 126 protrusions Annular filter element 128; 162 Dust discharge valve 130 Filter media 132 The internal 133 of the annular filter element 128 / 162 134 outer wall surface of annular filter element 128 / 162 Spiral winding ribs 136 The inner wall surface 138 of the annular filter element 128 / 162 Central tube 140 Open end plate 142 of annular filter element 128 / 162 The closed end plate 144 of the annular filter element 128 / 162 The folded enlargement 146 at the inner wall surface 138 of the annular filter element 128 / 162 Support element 148 The longitudinal axis 149 of the annular filter element 128 / 162 Positioning device 150 Connecting element 152 Radial inward cut 154 in end plate 142 Reverse bonding element 156 Knot 158 Horizontal edge 160 Increased spacing of 163 at the edge of the fold Shell fixed support tube 164 Threaded section 166 Connecting element 168 Tube body 170 Positioning device 172 The other annular filter element 174 Other filter media 176 Fuel Cell 186 Anode 188 Cathode 190 Electrolyte 192 Gas diffusion layer 193 Horizontal sections 194, 196 Bipolar plate 198 Hydrogen inlet 200 Air Inlet 202 Outlet 204.

Claims

1. An annular filter element (26, 28'; 128; 162) for air filtration, particularly for filtering the intake air of a fuel cell (186), include The filter media bodies (30, 32; 132), which surround the interior (34, 36; 133) and Open end discs (48, 52; 142) and closed end discs (50, 54; 144) tightly seal the filter media body (30, 32; 132) in the axial direction. in, The filter media body (30, 32; 132) includes a folded corrugated member with folded enlargements (102; 114; 146) disposed on the inner wall surface (40; 44; 138), and The open end plate (48, 52; 142) includes a cut (100; 116; 154) which is aligned with the folded enlargement (102; 114; 146).

2. The annular filter element (26, 28', 128; 162) according to claim 1, wherein, In the region of the folded enlargement (102, 114, 146), the folding angle (106; 120) and / or the folding distance is greater than the folding angle or folding distance of the plurality of folds of the folded corrugated member.

3. The annular filter element (26, 28'; 128; 162) according to any one of the preceding claims, wherein, The folded enlargement (102; 114; 146) extends across a portion of the height of the folded corrugated member or across its entire height.

4. The annular filter element (26; 28'; 128; 162) according to any one of the preceding claims, wherein, The filter media (30, 32; 132) comprises a hollow cylindrical shape.

5. The annular filter element (128; 162) according to any one of the preceding claims, wherein, Multiple folded enlargements (146) are distributed around the inner circumference of the folded corrugated member, and wherein the open end plate (142) includes multiple cuts (154), one of which is aligned with one of the folded enlargements (146).

6. The annular filter element (128; 162) according to claim 5, wherein, The folded enlargement (146) and the cut (154) are arranged about the longitudinal axis (149) in a mode that does not have rotational symmetry.

7. The annular filter element (26, 28'; 128; 162) according to any one of the preceding claims, wherein, The at least one cut (100; 116; 154) of the open end plate (48, 52; 142) opens radially inward.

8. The annular filter element (26, 28'; 128; 162) according to any one of the preceding claims, wherein, The incision gradually narrows radially outward and / or widens radially outward, and / or wherein, At least one lateral edge (160) of the cut (100; 116; 154) includes at least one knot (158).

9. The annular filter element (128) according to any one of the preceding claims further includes a fluid-permeable central tube (140), said central tube being disposed on the inner wall surface (138) of the filter media body (132) and indirectly or directly attached to said filter media body (132), wherein, At least one support element (148) is arranged at the central tube (140), wherein the support element (148) and the central tube (140) are formed as one unit, wherein the support element (148) extends radially outward into the folded enlargement (146).

10. The annular filter element (26, 28'; 128; 162) according to any one of the preceding claims, wherein, The open end plate (48, 52; 142) includes at least one continuous circumferential seal (55) for contact at the filter housing (12), and in particular, the seal (55) is formed as a sealing flange (122) projecting in the axial direction.

11. The annular filter element (26, 28') according to claim 10, wherein, The seal (55) is radially outwardly surrounding the at least one cutout (100; 116), preferably wherein the seal (55) includes a radially outwardly oriented protrusion (128) in the region of the cutout (100; 116).

12. The annular filter element (128; 162) according to claim 10, wherein, The at least one cut (154) extends axially at the inner circumference of the seal (55), and in particular, the seal (55) includes at least one recess at the inner circumference, the recess being aligned with the cut (154).

13. A filtration device (10.1-10.8) comprising a filter housing (12) having at least a fluid inlet (22) and a fluid outlet (24), and further comprising an annular filter element arrangement structure (20) disposed within the filter housing (12) and separating the fluid inlet (22) from the fluid outlet (24), wherein, The annular filter element arrangement structure (20) includes at least one first annular filter element (26, 28'; 128, 162) according to any one of the preceding claims, wherein the filter device (10.1-10.8) includes a positioning device (60; 108; 150; 172) having at least one engaging element (62; 110; 152; 168) extending in a radially outward direction, wherein the folded enlargement (102; 114; 146) forms at least partially a reverse engaging element (98; 112; 156) on the inner wall surface (40; 44; 138) of the filter media body (30; 32; 132) of the first annular filter element (26; 28'; 128; 162), and wherein the engaging element (62; 110; 152; 168) engages the reverse engaging element (98; 112; 156).

14. The filtration device (10.1-10.5; 10.8) according to claim 13 further includes a support tube (96; 111; 164) attached to the filter housing (12), particularly non-releasably attached, which is releasably arranged within (34, 36; 133) the filter media body (30; 32; 132) of the first annular filter element (26; 28'; 162), wherein, The engagement element (62; 110; 168) of the positioning device (68; 108; 172) is arranged at the support tube (96; 111; 164).

15. The filtration device (10.8) according to claim 14, wherein, The additional annular filter element (174) of the annular filter element arrangement structure (20) and the additional filter media body (176) are indirectly or directly attached radially outward to the support tube (164).

16. The filtration device (10.1; 10.5) according to claim 14, wherein, An internal annular filter element (28; 28') of the annular filter element arrangement structure (20) is arranged radially inside the support tube (96), which includes a second reverse engagement element (64) on its outer wall surface (42). The engagement element (62) of the support tube (96) engages radially outward with the reverse engagement element (98) of the first annular filter element (26), and the engagement element (62) of the support tube (96) engages radially inward with the second reverse engagement element (64) of the internal annular filter element (28; 28').

17. The filtration device (10.2-10.6) according to any one of claims 13 to 16, wherein, The annular filter element arrangement structure (20) further includes an outer annular filter element (26; 26') having a filter media body (30), wherein the filter media body (30) of the outer annular filter element (26; 26') surrounds the interior (34), wherein the first annular filter element (28') is at least partially housed within the interior (34) of the filter media body (30) of the outer annular filter element (26; 26').

18. The filtration device (10.2-10.6) according to claim 17, wherein, The filter housing (12) includes a housing positioning device (82) specifically for positioning the outer annular filter element (26; 26') relative to the filter housing (12) at a defined relative angle, wherein the housing positioning device (82) includes a housing engagement element (84), which extends radially inward and engages a corresponding housing reverse engagement element (86) of the outer annular filter element (26, 26').

19. The filtration device (10.2; 10.6) according to claim 17 or 18, wherein, The external annular filter element (26') includes a fluid-permeable inner tube (56) disposed on the inner wall surface (40) of the filter media body (30) of the external annular filter element (26') and indirectly or directly fastened to the filter media body (20) of the external annular filter element (26'). An additional engaging element (62') is disposed on the inner tube (56), which is integral with the inner tube (56). This additional engaging element (62') extends radially inward and engages with the additional reverse engaging element (64') on the outer wall surface (42) of the filter media body (32) of the first annular filter element (28').

20. Use of the filtration device (10.1-10.8) according to any one of claims 13 to 19 as a cathode air filter for a fuel cell (186).

21. Use of the annular filter element (26, 26'; 128; 162) according to any one of claims 1 to 12 in a filter device (10.1-10.8) having a filter housing (12), wherein, Engaging elements (62; 110; 152; 168) arranged on the filter housing (12) engage the folded enlargement (102; 114; 146).

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