Filter element, related filter assembly and filter package

Abstract

The present disclosure relates to: a flexible filter media pack arranged in a tubular manner about an axis; a first open end cap connected in a fluid-tight manner to the first axial end of the filter media pack; and a second open end cap connected in a fluid-tight manner to the second axial end of the filter media pack, characterized in that the first end cap is flexible and non-destructively deformable between a first shape and a second, different shape; and related filter packages and filter assemblies.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application was filed on February 14, 2024 as a PCT international application, and claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 484,835 filed on February 14, 2023, and claims priority to European Patent Application Serial No. 23159264.3 filed on February 28, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to the field of gas filtration, such as air filtration. The present disclosure relates to the field of filter assemblies comprising a filter element disposed in a sealed manner within a filter housing such that air flowing from an inlet of the housing to an outlet of the housing is filtered by the filter element. Preferably, the assembly is used to filter air that is subsequently directed to, for example, an engine of a vehicle. Background Art

[0004] Filter elements, also known as filter cartridges, are used in various filtration applications. The fluid to be filtered can be a liquid or a gas, such as air.

[0005] Indeed, in many cases, it is necessary to filter contaminants from fluid streams. For example, air flowing to engines used in motor vehicles, power generation equipment, construction equipment, or other equipment, gas flowing to gas turbine systems, and air flowing to various combustion furnaces can carry particulate contaminants. For these systems, it is preferable to remove or at least reduce the amount of contaminants from the fluid.

[0006] A filter element includes filter media that is used to remove contaminants as a fluid flows through the filter media. Commonly used and commercially available filter media include pleated media and fluted media. When dust and / or particulate matter accumulated in the filter media exceeds a certain threshold load, the filter element needs to be replaced. The filter element is typically mounted in a housing in a replaceable manner.

[0007] The industry needs new solutions that make it easy to install the correct filter element into a filter housing, especially in complex filter housing designs, without installing the wrong filter element. For example, complex filter housing designs may be caused by boundary conditions imposed by the geometry and position of other vehicle / engine components.

[0008] There is also a need in the industry for compact packaging of filter elements and filter housings.

[0009] Furthermore, there is a need in the industry for filter elements having an increased ratio of filter media volume to internal housing volume.

[0010] Furthermore, solutions that reduce the weight of filter elements and the amount of material used are favored by the industry.

[0011] Additionally, there is a need for a filter housing and assembly that allows for easy removal of the housing cover and facilitates proper positioning of the housing cover on the housing.

[0012] It is often very important to install the correct filter element for a specific filter housing in the correct manner to avoid damage to the equipment or engine using the filtered air / gas.

[0013] There is also a need in the industry for a filter assembly that allows for internal inspection of an installed filter element without removing the element.

[0014] There is also a need in the industry for a filter assembly that allows for inspection of an installed filter element with reduced risk of breaching a seal of the filter element toward the main housing. Summary of the Invention

[0015] It is an object of embodiments of the present disclosure to provide a filter element, a package comprising such a filter element, and an assembly comprising such a filter element.

[0016] The present disclosure is defined by the appended independent claims. The dependent claims define advantageous embodiments.

[0017] In a first aspect of the present disclosure, a filter element is disclosed, comprising (or consisting of): a flexible filter media pack arranged in a tubular manner about an axis; a first open end cap connected to a first axial end of the filter media pack in a fluid-tight manner; and a second open end cap connected to a second axial end of the filter media pack in a fluid-tight manner, wherein the first end cap is flexible and capable of non-destructively deforming, for example, between a first shape (or state) (corresponding to a first configuration of the element) and a different, preferably substantially different, second shape (or state) (corresponding to the second configuration of the element).

[0018] An advantage is that a filter housing can be designed that allows installation of the disclosed filter element but not standard filter elements, thereby preventing the use of an incorrect filter element or incorrect installation of a filter element. Another advantage is that the disclosed filter element can be used in relatively complex and compact housing configurations. Furthermore, the disclosed filter element can be packaged in a more compact manner. Because at least the first end cap and the filter medium can be deformed non-destructively, the filter medium can be in a twisted configuration when used in the associated housing, thereby increasing the ratio of the filter medium volume to the housing internal volume.

[0019] For the purposes of this disclosure, a filter element, end cap, or filter media pack may be deformed non-destructively if deformation of the corresponding component does not affect its integrity or performance. Preferably, the corresponding component is flexible, and more preferably, the corresponding component is elastically deformable to the extent necessary to perform its function, for example, to reduce its size to access an initially undersized filter housing maintenance opening, or to conform to a filter housing cavity of sufficient volume but different shape. A component is elastically deformable if, after deformation, it can return to its original, undeformed state to the extent necessary to perform its function.

[0020] It should be understood that the filter media pack can be deformed non-destructively while maintaining a fluid-tight connection with the first and second end caps. The fluid media pack may, for example, comprise a pleated media pack. A sheet material is pleated to form the pleated media, which may be single-layer or multi-layer. For example, the sheet material may comprise one, two, or more filter layers and / or coalescing layers. The sheet material may also comprise an inner support layer and / or an outer support layer. However, the composite and pleated media should remain capable of deforming in a non-destructive manner. Preferably, the composite and pleated media is flexible. Preferably, the composite and pleated media is elastically deformable. Preferably, the pleated media is arranged in a tubular manner and has a pleat direction parallel to the longitudinal axis of the filter element, at least in the first configuration of the element. The end pleats of the pleated media are preferably permanently connected to each other by gluing, embedding (e.g., polyurethane) or other related techniques, and preferably, the end pleats of the pleated media are permanently connected to each other by gluing, embedding (e.g., polyurethane) or other related techniques, without loss of filtration capacity for exceeding the length of a single pleat. The end folds are the first and last folds of the paper to be folded. Preferably, there is no intermediate axially extending connecting structure at each of the end folds for connecting the end folds.

[0021] According to certain embodiments, the part that can nondestructive deformation of filter element can be deformed in a continuous manner, for example, without using hinged features, the part that can nondestructive deformation of filter element can be deformed in a continuous manner. According to certain embodiments, filter element can be deformed continuously, nondestructively as a whole. According to certain embodiments, filter element can be deformed elastically as a whole.

[0022] Each of the first and second open end caps of the filter element is preferably manufactured from a single piece. Each of the first and second open end caps of the filter element can be formed, for example, by potting, for example, polyurethane (PU) or foamed polyurethane potting. Alternatively, each of the first and second open end caps of the filter element can be manufactured separately and sealingly attached to the first or second end of the media pack using relevant techniques, such as gluing, potting, or injection molding. Preferably, the end cap is an end disc, for example, a continuous annular ring.

[0023] According to certain embodiments, the first end cap comprises or is made of a flexible material. According to certain embodiments, the second end cap comprises or is made of a flexible material. According to certain embodiments, both the first end cap and the second end cap comprise or are made of a flexible material.

[0024] According to a preferred embodiment, the minimum radial cross-sectional dimension of the second shape of the first open end cap is at least 5%, or at least 10%, or at least 15%, or at least 20%, or at least 25%, or at least 30%, or at least 40%, or at least 50%, or at least 75% smaller than the minimum radial cross-sectional dimension of the first shape.

[0025] According to a preferred embodiment, the minimum radial cross-sectional dimension of the second shape of the first open end cap is at least 5 mm, or at least 10 mm, or at least 15 mm, or at least 20 mm, or at least 25 mm, or at least 5 cm smaller than the minimum radial cross-sectional dimension of the first shape of the first open end cap.

[0026] According to a preferred embodiment, the maximum radial cross-sectional dimension of the second shape of the first open end cap is at least 5%, or at least 10%, or at least 15%, or at least 20%, or at least 25%, or at least 30%, or at least 40%, or at least 50%, or at least 75% smaller than the maximum radial cross-sectional dimension of the first shape.

[0027] According to a preferred embodiment, the maximum radial cross-sectional dimension of the second shape of the first open end cap is at least 5 mm, or at least 10 mm, or at least 15 mm, or at least 20 mm, or at least 25 mm, or at least 5 cm smaller than the maximum radial cross-sectional dimension of the first shape of the first open end cap.

[0028] According to a preferred embodiment, the first end cap is elastically deformable.

[0029] Advantageously, after deformation of the end cap and the filter element, for example for insertion or removal of the filter element through a relatively small insertion opening of an air filter housing or a packaging device, the end cap automatically returns to its initial position, thereby assuming the corresponding first configuration of the filter element. In this case, the first state of the end cap and the first configuration of the filter element are the undeformed state of the end cap or the filter element, i.e., the state in which the end cap or the filter element can return without the application of any external force.

[0030] According to a preferred embodiment, the first configuration of the media pack may have a cross-section along a plane perpendicular to the filter element that is circular, rectangular, rounded rectangular, oblong, elliptical, or may have other regular shapes.

[0031] According to a preferred embodiment, the first end cap is connected to the filter medium and may be manufactured by (eg polyurethane (PU)) potting.

[0032] According to a preferred embodiment, the first end cap includes a first circumferential sealing portion, preferably, the first circumferential sealing portion is formed integrally with the first end cap. For example, the sealing portion can be formed of a polyurethane material, for example, the sealing portion can include the same material as the first end cap. Alternatively, the first circumferential sealing portion can be manufactured separately, or the first circumferential sealing portion is manufactured in a separate step of the manufacturing process and attached to the first end cap in a sealing manner by relevant technology. An alternative embodiment of the first sealing portion is a TPE (thermoplastic elastomer) sealing portion.

[0033] For the purposes of this disclosure, a (e.g., first or second) circumferential seal portion (or sealing surface) is a seal portion (or sealing surface) that forms a circumferential portion or a seal portion (or sealing surface) that surrounds a corresponding opening, such as a central opening or a first end cap or a second end cap. The circumferential seal portion and the associated circumferential surface cooperate to provide an airtight seal. The orientation of such a circumferential seal portion or circumferential sealing surface portion can generally be radially inward, radially outward, or in an axial direction, or a combination of the two. The seal between the circumferential seal portion and the circumferential sealing surface portion can generally be directed radially inward, radially outward, or in an axial direction, or a combination of the two.

[0034] Preferably, the first sealing portion is non-destructively deformable, preferably, the first sealing portion is elastically deformable.

[0035] According to a preferred embodiment, the first circumferential seal has N-fold rotational symmetry with respect to the axis of the filter media pack, for example, the first circumferential seal has 1-fold rotational symmetry with respect to the axis of the filter media pack. Advantageously, the N-fold rotational symmetry introduced into the first circumferential seal and the corresponding sealing surface on the housing cover facilitates alignment of the filter element relative to the cover.

[0036] For the purposes of this disclosure, an object or projection is said to have N-fold rotational symmetry about an axis of rotation if it can be projected onto itself by performing N different rotations less than or equal to 360° about that axis of rotation. An object or projection with single-fold rotational symmetry is one that does not have any rotational symmetry other than 360°.

[0037] According to a preferred embodiment, the first circumferential seal is arranged along an inclined plane with respect to a plane perpendicular to the axis of the filter media pack.

[0038] According to a preferred embodiment, the first end cap can be deformed in the radial direction (eg by more than 10%) by a radial force component of less than 40N, or less than 30N, or less than 20N, or less than 10N.

[0039] According to a preferred embodiment, the first end cap further comprises at least one manipulation means, such as a handle, adapted and arranged to pull a portion of the first end cap radially inwards.

[0040] According to a preferred embodiment, the steering means comprises a handle bar or structure bridging opposite sides of the open end cap over a central opening in the first end cap.

[0041] According to a preferred embodiment, the operating means comprises at least one baffle or ear-like structure pointing radially inwards or radially outwards. For example, the operating means may comprise two baffles or ear-like structures pointing radially inwards, the two baffles or ear-like structures being arranged at opposite sides of the central opening, for example, the two baffles or ear-like structures being arranged at diametrically opposite sides of the central opening.

[0042] According to a preferred embodiment, the filter media pack is of a conical type, i.e. the filter media pack is arranged in a conical manner, wherein the cross-section of the respective cone decreases from a first axial end of the media pack to a second axial end of the media pack, and wherein the second end cap has a smaller outer diameter than the first end cap.

[0043] This offers the advantage that filter media support means, such as tower-like structures, which, for example, protrude from the inner surface of the housing cover, can be easily inserted into the filter media pack. It is further advantageous if the filter media pack is at least partially formed by the filter media support means or the tower-like structures during installation.

[0044] Preferably, the outer diameter of the second end cap may be smaller than the outer diameter of the first end cap by more than 5%, or more than 10%, or more than 15%, or more than 20%, or more than 25%, or more than 30%. Preferably, the outer diameter of the second end cap is within the range of 80% to 90% of the outer diameter of the first end cap.

[0045] According to a preferred embodiment, the second end cap is flexible and non-destructively deformable, for example, the second end cap is non-destructively deformable between a first shape and a different, preferably substantially different, second shape.

[0046] According to a preferred embodiment, the minimum radial cross-sectional dimension of the second shape of the second open end cap is at least 5%, or at least 10%, or at least 15%, or at least 20%, or at least 25%, or at least 30%, or at least 40%, or at least 50%, or at least 75% smaller than the minimum radial cross-sectional dimension of the first shape.

[0047] According to a preferred embodiment, the minimum radial cross-sectional dimension of the second shape of the second open end cap is at least 5 mm, or at least 10 mm, or at least 15 mm, or at least 20 mm, or at least 25 mm, or at least 5 cm smaller than the minimum radial cross-sectional dimension of the first shape of the second open end cap.

[0048] According to a preferred embodiment, the maximum radial cross-sectional dimension of the second shape of the second open end cap is at least 5%, or at least 10%, or at least 15%, or at least 20%, or at least 25%, or at least 30%, or at least 40%, or at least 50%, or at least 75% smaller than the maximum radial cross-sectional dimension of the first shape.

[0049] According to a preferred embodiment, the maximum radial cross-sectional dimension of the second shape of the second open end cap is at least 5 mm, or at least 10 mm, or at least 15 mm, or at least 20 mm, or at least 25 mm, or at least 5 cm smaller than the maximum radial cross-sectional dimension of the first shape of the first open end cap.

[0050] According to a preferred embodiment, the second end cap can be deformed in the radial direction (eg by more than 10%) by a radial force component of less than 40N, or less than 30N, or less than 20N, or less than 10N.

[0051] According to a preferred embodiment, the second end cap is elastically deformable.

[0052] The advantage is that after deformation of the end cap and filter element, for example, to insert or remove the filter element through a relatively small insertion opening of an air filter housing or packaging device, the end cap automatically returns to its initial position, thereby assuming the corresponding first configuration of the filter element. This is particularly advantageous when used in conjunction with an elastically deformable first end cap. In this case, the first state of the second end cap and the first configuration of the filter element are the undeformed state of the end cap or filter element, i.e., a state in which the end cap or filter element can return without the application of any external force.

[0053] According to a preferred embodiment, the second end cap is connected to the filter medium and may be manufactured by potting (eg polyurethane (PU)).

[0054] According to an alternative preferred embodiment, the second end cap is substantially rigid and, preferably, in the first configuration of the filter element, is smaller than said first end cap.

[0055] According to a preferred embodiment, the second end cap includes a second circumferential seal, preferably, the second circumferential seal is formed integrally with the second end cap. For example, the second circumferential seal can be made of a polyurethane material, for example, the second circumferential seal can include the same material as the second end cap.

[0056] Alternatively, the seal may be manufactured separately, or the seal may be manufactured in a separate step of the manufacturing process and attached to the second end cap in a sealing manner by relevant techniques.An alternative embodiment of the second seal is a TPE (thermoplastic elastomer) seal.

[0057] Preferably, the second circumferential sealing portion is non-destructively deformable, preferably the second circumferential sealing portion is elastically deformable.

[0058] According to a preferred embodiment, the second circumferential seal comprises N-fold rotational symmetry with respect to the axis of the filter media pack, for example, the second circumferential seal comprises 1-fold rotational symmetry with respect to the axis of the filter media pack. Advantageously, the introduction of N-fold rotational symmetry in the second circumferential seal and the corresponding sealing surface on the housing facilitates alignment of the filter element relative to (the second end of) the housing.

[0059] According to a preferred embodiment, the second circumferential seal is arranged along an inclined plane with respect to a plane perpendicular to the axis of the filter media pack.

[0060] According to a preferred embodiment, the second open end cap includes a central opening, and the second circumferential seal is implemented as a portion of the second end cap extending radially inwardly into the central opening. The radially inwardly extending portion includes at least one axially extending, circumferentially extending groove, channel, or recess, for example, V-shaped or U-shaped, disposed adjacent to the central opening. The groove, channel, or recess projects into the interior volume of the filter media pack. Preferably, the groove, channel, or recess projects into the interior volume of the filter media pack in a direction parallel to the axis of the filter media pack. Preferably, the sealing direction of the second circumferential seal is radial, and more preferably, the sealing direction of the second circumferential seal is radially inward.

[0061] According to a preferred embodiment, the filter media pack comprises pleated media, and the media comprises one or more layers selected from the group consisting of a media layer and a support layer.

[0062] According to a preferred embodiment, the filter media pack and / or the filter element is self-supporting.According to a preferred embodiment, the filter media pack is self-supporting in at least the axial direction.

[0063] According to an alternative embodiment, the filter media pack and thus the filter element is not self-supporting. For example, when the filter media pack and thus the filter element is vertically positioned on the first end cap, the filter media pack and thus the filter element will deform under its own weight due to the effect of gravity.

[0064] In a second aspect of the present disclosure, a package is disclosed, comprising a box, a bag or a sleeve, the package comprising a filter element according to any embodiment of the first aspect, wherein the filter element is maintained in an elastically deformed configuration by the inner side wall of the box, the bag or the sleeve.

[0065] In a third aspect of the present disclosure, a filter assembly is disclosed, comprising a filter housing having a housing axis and a filter element according to any embodiment of the first aspect, the filter housing comprising a filter insertion opening (commonly referred to as a maintenance opening), wherein the filter insertion opening is too small for inserting the first end cap into the filter housing in a first shape of the first end cap (or a first configuration of the filter element); and the filter insertion opening is large enough for inserting the first end cap into the filter housing in a second shape of the first end cap (a second configuration of the filter element).

[0066] According to a preferred embodiment, the insertion opening comprises at least one undercut, and a projection of the filter element along the housing axis intersects with a projection of the undercut along the housing axis, the intersection corresponding to an overlapping area of ​​the projections. The projections can, for example, lie on a plane perpendicular to the housing axis.

[0067] According to a preferred embodiment, the projected overlap area is more than 1%, or more than 2%, or more than 3%, or more than 4%, or more than 5%, or more than 10%, or more than 20% of the projected area of ​​the filter element along the housing axis. In the case of multiple undercuts, the projected overlap area is associated with the sum of the individual intersections and the associated overlap areas.

[0068] According to a preferred embodiment, the housing includes a housing cover for covering the insertion opening, the housing cover being shaped to be substantially complementary to or complementary to the one or more undercut portions. For example, the one or more undercut portions may be defined by one or more flat portions of the insertion opening, and the housing cover may have one or more corresponding flat portions along its sidewalls.

[0069] According to a preferred embodiment, the filter assembly includes a housing cover for covering the insertion opening, wherein the housing cover and the filter housing are adapted so that the housing cover and the filter housing meet along an inclined plane, the inclined plane being such that the housing length at the side corresponding to the projected overlapping area is longer than the housing length at the opposite side of the housing.

[0070] According to a preferred embodiment, the filter assembly includes a shell cover for covering the insertion opening, the shell cover includes an internal support structure of the filter media pack, and the internal support structure of the filter media pack is, for example, a tower-shaped structure. The internal support structure of the filter media pack preferably has a conical shape, and the internal support structure of the filter media pack protrudes from the inner surface starting from the proximal end portion of the cover toward the distal end portion.

[0071] According to a preferred embodiment, the filter assembly includes a housing cover for covering the insertion opening. The housing cover includes a sensor holder for a sensor, such as a MAF sensor, a temperature sensor, a pressure sensor, an RFID sensor, or a tag, and optionally a corresponding sensor. Advantageously, the central area of ​​the filter housing volume beneath the housing cover is part of the clean air side of the filter housing, allowing the sensor to be placed on the housing cover and within sight during servicing.

[0072] According to a preferred embodiment, the filter assembly comprises a housing cover for covering the insertion opening, the housing cover comprising a sealing surface for receiving the first circumferential seal in a sealing manner when the cover is mounted on the filter housing.

[0073] According to a preferred embodiment, the filter housing comprises a housing cover for covering the insertion opening, and the filter housing comprises a first end and a second end, the first end comprising the filter insertion opening and being suitable for receiving the cover, the second end being arranged at an end opposite to the first end and comprising an outlet opening, the second end further comprising a sealing surface complementary to the second circumferential seal for receiving the second circumferential seal in a sealed manner.

[0074] According to a preferred embodiment, the filter assembly includes a housing cover for covering the insertion opening. The second open end cap of the filter element includes a central opening, and the second circumferential seal is implemented as a portion of the second end cap that extends radially inwardly into the central opening. The radially inwardly extending portion includes at least one axially extending, circumferentially extending, for example, V-shaped or U-shaped groove, groove or recess arranged adjacent to the central opening, the groove, groove or recess protruding into the inner volume of the filter media pack, preferably protruding into the inner volume of the filter media pack in a direction parallel to the axis of the filter media pack. The housing cover includes an internal support structure for the filter media pack, for example a tower-like structure, the filter media pack internal support structure preferably having a conical shape, and the filter media pack internal support structure protruding from the inner surface of the cover starting from the proximal end toward the distal end. The distal end of the support structure is arranged and adapted to be received by an axially extending circumferential groove, groove or recess, for example, V-shaped or U-shaped, of the second circumferential seal of the filter element, and preferably, the distal end of the support structure is arranged and adapted to provide a radially inward back pressure to the circumferential seal toward the sealing surface of the filter housing when the cover is mounted on the housing.

[0075] The distal end of the support structure may be sealed axially and / or radially within a V-shaped or U-shaped groove, channel or recess of the second circumferential seal.

[0076] According to a preferred embodiment, the housing further comprises at least one partial volume portion for receiving a portion of the first end cap in the housing, the partial volume portion being arranged in the housing below the undercut position, preferably, the partial volume portion being arranged in the housing just below the undercut position or adjacent to the undercut position, preferably, the partial volume portion being adjacent to the insertion opening.

[0077] According to a preferred embodiment, the filter media pack of the filter element is mounted in a twisted configuration.

[0078] The advantage is that the deformable filter element can have a maximum length that is greater than the height of the mounting cavity in the housing and by twisting the media the length of the filter element can be shortened to fit the housing, thereby introducing more filter media into the same internal housing volume.

[0079] According to a preferred embodiment, the housing comprises a housing sidewall arranged substantially along an outer radial surface of the filter media pack, the sidewall being open and comprising a lattice structure.

[0080] According to a preferred embodiment, the radial side walls of the cover are open and comprise a grid structure.

[0081] According to a preferred embodiment, at least one of the lattice structures of the cover or the housing side wall comprises one or more flow guiding means, such as flow guiding ribs, fins or blades.

[0082] An advantage is that flow directing devices such as ribs, fins or vanes can be positioned in a predetermined configuration, for example, to provide an optimal flow direction relative to the pleat position of the filter media pack or the expected dust loading of the media. To achieve good filtration performance and maximize utilization of the pleated filter media, flow distribution across each pleat is crucial. In prior art installations, dust may settle on one part of the element, resulting in uneven loading, which in turn leads to higher resistance and suboptimal utilization of the filter media. By controlling any one or a combination of the position, spacing and / or angle of the ribs / fins / vanes, the air flow around the pack can be controlled to provide a good, even flow distribution across all pleats. The fins, ribs or vanes can also be used for sound attenuation purposes or to straighten the airflow, for example for flow measurement purposes.

[0083] In a fourth aspect of the present disclosure, a filter housing is disclosed, which includes an inlet and an outlet and is suitable for receiving a replaceable filter element in a sealed manner so that air flowing from the inlet of the housing to the outlet of the housing is filtered by the filter element, the housing including a maintenance opening for receiving the filter element in the main part of the housing, and the housing including a housing cover for closing the maintenance opening, wherein the inlet of the housing is arranged in the main part and / or the housing cover, and wherein the inlet includes a grid-like inlet structure.

[0084] According to a preferred embodiment, the housing comprises a housing sidewall which is arranged substantially along an outer radial surface of the filter media pack when the filter media pack is installed in the housing, and the outer radial surface comprises a lattice structure.

[0085] According to a preferred embodiment, the radial side wall of the cover comprises a grid structure.

[0086] According to a preferred embodiment, at least one of the lattice structures of the cover or the housing side wall comprises one or more flow guiding means such as flow guiding ribs or vanes. The advantages thereof are similar to those of the flow guiding means of the main housing.

[0087] According to a preferred embodiment, the main part of the housing and / or the housing cover comprises plastic.

[0088] According to a preferred embodiment, the main part of the housing and / or the housing is formed by injection moulding.

[0089] In a fifth aspect of the present disclosure, a filter element is disclosed, comprising: a flexible filter media pack, the filter media pack being arranged in a tubular manner around an axis; a first open end cap, the first open end cap being connected to a first axial end of the filter media pack in a fluid-tight manner; and a second open end cap, the second open end cap being connected to a second axial end of the filter media pack in a fluid-tight manner, wherein the second open end cap comprises a central opening and a second circumferential seal portion, the second circumferential seal portion comprises a portion of the second end cap extending radially inwardly into the central opening, the portion extending radially inwardly comprising at least one circumferential groove, groove or recess arranged adjacent to the central opening, the groove, groove or recess protruding into an interior volume portion of the filter media pack or the filter element.

[0090] According to a preferred embodiment, the circumferential grooves, channels or recesses are oriented in a direction parallel to the axis of the filter media pack.

[0091] According to a preferred embodiment, the filter media pack is of a conical type, i.e. the filter media pack is arranged in a conical manner, wherein the cross-section of the respective cone decreases from a first axial end of the media pack to a second axial end of the media pack, and the second end cap has a smaller outer diameter than the first end cap.

[0092] According to a preferred embodiment, the second end cap is flexible and can be non-destructively deformed, for example between a first shape and a second, different shape.

[0093] According to a preferred embodiment, the minimum radial cross-sectional dimension of the second shape of the second open end cap is at least 5% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cap is at least 10% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cap is at least 15% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cap is at least 20% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cap is at least 25% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cap is at least 30% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cap is at least 40% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cap is at least 50% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cap is at least 75% smaller than the minimum radial cross-sectional dimension of the first shape.

[0094] According to a preferred embodiment, the minimum radial cross-sectional dimension of the second shape of the second open end cap is at least 5 mm, or at least 10 mm, or at least 15 mm, or at least 20 mm, or at least 25 mm, or at least 5 cm smaller than the minimum radial cross-sectional dimension of the first shape of the second open end cap.

[0095] According to a preferred embodiment, the second end cap can be deformed in the radial direction by a radial force component of less than 40N, or less than 30N, or less than 20N, or less than 10N.

[0096] According to a preferred embodiment, the second end cap is elastically deformable.

[0097] According to a preferred embodiment, the second end cap is substantially rigid.

[0098] According to a preferred embodiment, the second circumferential seal is formed integrally with the second end cap.

[0099] According to a preferred embodiment, the second circumferential seal comprises an N-fold rotational symmetry with respect to the axis of the filter media pack, eg the second circumferential seal comprises a 1-fold rotational symmetry with respect to the axis of the filter media pack.

[0100] According to a preferred embodiment, the second circumferential sealing portion includes at least one protrusion protruding radially inwardly or outwardly.

[0101] According to a preferred embodiment, the second circumferential sealing portion comprises at least one protrusion protruding axially inwardly or outwardly.

[0102] According to a preferred embodiment, the second circumferential seal is arranged along an inclined plane with respect to a plane perpendicular to the axis of the filter media pack.

[0103] According to a preferred embodiment, the filter media pack comprises pleated media, and the media comprises one or more layers selected from a media layer and a support layer.

[0104] According to a preferred embodiment, the second end cap is connected to the filter medium by potting and can be manufactured by potting.

[0105] In a sixth aspect of the present disclosure, a filter assembly is disclosed, comprising a filter housing having a housing axis and a filter element according to any embodiment of the fifth aspect arranged in the housing along the housing axis, the filter housing comprising a housing cover, the housing cover comprising a filter media pack internal support structure, the filter media pack internal support structure being, for example, a tower-like structure, the filter media pack internal support structure preferably having a conical shape, the filter media pack internal support structure protruding from an inner surface starting from a proximal end portion at the cover toward a distal end portion. The filter housing comprises a first end and a second end portion, the first end comprising a filter insertion opening and being adapted to receive the cover, the second end being arranged at an end opposite to the first end and comprising an outlet opening, the second end further comprising a sealing surface complementary to a second circumferential seal portion for receiving the second circumferential seal portion in a sealing manner.

[0106] According to a preferred embodiment, the distal end of the support structure is arranged and adapted to be received by an axially extending circumferential groove, groove or recess of the second circumferential seal of the filter element, and the distal end of the support structure is arranged and adapted to provide a radially outward back pressure to the circumferential seal toward the sealing surface of the filter housing when the cover is mounted on the housing.

[0107] According to a preferred embodiment, the second circumferential sealing portion includes at least one radially protruding convex portion, and the distal end portion of the support structure includes at least one radially inwardly protruding convex portion, and the at least one convex portion of the distal end portion of the support structure corresponds to the at least one radially protruding convex portion of the second circumferential sealing portion.

[0108] According to a preferred embodiment, the second circumferential sealing portion includes at least one axially protruding protrusion, and the distal end portion of the support structure includes at least one axially inwardly protruding protrusion, and the at least one protrusion of the distal end portion of the support structure corresponds to the at least one axially protruding protrusion of the second circumferential sealing portion.

[0109] In the seventh aspect of the present disclosure, a housing cover for a filter housing is disclosed, the housing cover comprising an axial end wall connected to a circumferential side wall arranged around a longitudinal axis, wherein a projection of the axial end wall along the longitudinal axis on a plane perpendicular to the longitudinal axis (or its profile) comprises a 1-fold rotational symmetry around the longitudinal axis.

[0110] According to a preferred embodiment, the projection is substantially rotationally symmetrical, the projection being for example circular, but the projection is made rotationally asymmetrical by being arranged to cut one, two or more flat or arcuate portions of the chord.

[0111] According to a preferred embodiment, the side wall includes or defines a lower edge around the shell engagement opening, and the circumferential side wall is interrupted (or includes one or more annular gaps) within one or more angular ranges around the longitudinal axis, or the circumferential side wall is straight or substantially straight (in another view, the circumferential side wall includes a straight portion).

[0112] According to a preferred embodiment, the profile of the axial end wall generally corresponds to one or more successive portions of a predetermined annular shape, the one or more successive portions being connected between adjacent annular portions via one or more chords of the annular shape, the circumferential side wall being interrupted or straight in the region corresponding to the chords (thus defining one or more flat portions of the housing cover).

[0113] According to a preferred embodiment, the housing cover further comprises a sensor port opening in the axial end wall.

[0114] According to a preferred embodiment, the housing cover comprises an inner surface and a circumferential sealing surface portion, which is arranged on the inner surface for receiving the filter element sealing portion.

[0115] According to a preferred embodiment, the circumferential sealing surface portion protrudes axially from the axial end wall on the inner surface.

[0116] According to a preferred embodiment, the circumferential sealing surface portion comprises an N-fold rotational symmetry.

[0117] According to a preferred embodiment, the housing cover comprises one or more axial end wall openings in the axial end wall.

[0118] According to a preferred embodiment, the housing cover comprises one or more axial end wall outlet openings positioned radially within the circumferential sealing surface portion, for example the housing cover comprises one or more centrally positioned axial end wall outlet openings positioned radially within the circumferential sealing surface portion.

[0119] According to a preferred embodiment, the housing cover includes: a second circumferential sealing surface portion, which is arranged on the inner surface for accommodating a second filter element sealing portion, and the second circumferential sealing surface portion is radially arranged within the first circumferential sealing surface portion; and one or more axial end wall inlet openings, such as one or more centrally positioned axial end wall inlet openings, and the axial end wall inlet opening is radially arranged within the second circumferential sealing surface portion.

[0120] According to a preferred embodiment, the second circumferential sealing surface portion comprises an N-fold rotational symmetry.

[0121] According to a preferred embodiment, the housing cover comprises a filter medium support structure which protrudes axially or predominantly axially from an inner surface starting from the axial end wall.

[0122] According to a preferred embodiment, the media support structure comprises a tower-like structure, preferably a conical tower-like structure, which extends axially from a proximal end at the inner surface of the cover to a distal end away from the cover. The tower-like structure can be manufactured separately from the cover and then joined, or the end cap and the housing cover can be manufactured in a single step.

[0123] According to a preferred embodiment, the distal end of the tower-like structure comprises an N-fold rotational symmetry about the longitudinal axis.

[0124] According to a preferred embodiment, the lower edge is defined by a plane inclined relative to a direction perpendicular to the longitudinal axis. The advantage is that, due to the inclination, when a force is applied to the cover (e.g., by manual operation or a cover closing device), the cover automatically aligns with the housing.

[0125] According to a preferred embodiment, the axial end wall is arranged perpendicular to the longitudinal axis, and the circumferential side wall extends between a minimum width and a maximum width, wherein the minimum width is located at the minimum axial distance between the lower edge and the axial end wall, and the maximum width is located at the maximum axial distance between the lower edge and the axial end wall.

[0126] According to a preferred embodiment, the housing cover side wall comprises one or more housing cover side wall openings.

[0127] According to a preferred embodiment, the housing cover further comprises at least a sub-component of a cover closure device or arrangement, which is arranged at or adjacent to a location where the circumferential sidewall is interrupted (or comprises one or more gaps) or where the circumferential sidewall is straight or substantially straight. Examples of such closure devices or arrangements are, for example, latches and hook-like arrangements, finger locks, rubber bands, clamps, bolts and nuts, wing nuts, etc. Preferably, the sub-component interacts with its counterpart on the housing, for example, preferably with a counterpart arranged on an undercut portion of the housing inlet opening, or with a counterpart arranged adjacent to an undercut portion of the housing inlet opening.

[0128] In an eighth aspect of the present disclosure, a filter assembly is disclosed, comprising: a main shell having a maintenance opening for receiving a filter element into the shell; and a shell cover according to any embodiment of the seventh aspect, the shell cover being used to cover the maintenance opening, wherein the maintenance opening comprises at least one or more undercut portions, and when the shell cover is placed on the main shell, the undercut portion is complementary to the interrupted portion or straight portion of the shell cover.

[0129] In a ninth aspect of the present disclosure, a housing cover for a filter housing is disclosed, the housing cover comprising an axial end wall connected to a circumferential side wall arranged around a longitudinal axis, the housing cover defining a lower edge of the side wall, the lower edge surrounding a filter housing engagement opening, wherein the lower edge is defined by a plane inclined relative to a direction perpendicular to the longitudinal axis.

[0130] According to a preferred embodiment, the axial end wall is arranged perpendicular to the longitudinal axis, and the circumferential side wall extends between a minimum width and a maximum width, wherein the minimum width is located at the minimum axial distance between the lower edge and the axial end wall, and the maximum width is located at the maximum axial distance between the lower edge and the axial end wall.

[0131] According to a preferred embodiment, the housing cover side wall comprises one or more housing side wall openings.

[0132] According to a preferred embodiment, the housing cover further comprises a sensor port opening in the axial end wall.

[0133] According to a preferred embodiment, the housing cover further comprises an inner surface and a circumferential sealing surface portion, which is arranged on the inner surface for receiving the filter element sealing portion.

[0134] According to a preferred embodiment, the circumferential sealing surface portion protrudes axially from the axial end wall on the inner surface.

[0135] According to a preferred embodiment, the circumferential sealing surface portion comprises an N-fold rotational symmetry.

[0136] According to a preferred embodiment, the housing cover further comprises one or more axial end wall openings in the axial end wall.

[0137] According to a preferred embodiment, the housing cover comprises one or more axial end wall outlet openings, such as a centrally located one or more axial end wall outlet openings, which are positioned radially inside the circumferential sealing surface portion.

[0138] According to a preferred embodiment, the housing cover also includes: a second circumferential sealing surface portion, which is arranged on the inner surface for accommodating a second filter element sealing portion, and the second circumferential sealing surface portion is radially arranged within the first circumferential sealing surface portion; and one or more centrally positioned axial end wall inlet openings, which are radially arranged within the second circumferential sealing surface portion.

[0139] According to a preferred embodiment, the second circumferential sealing surface portion comprises an N-fold rotational symmetry.

[0140] According to a preferred embodiment, the housing cover further comprises a filter media support structure protruding axially from the inner surface starting from the axial end wall.

[0141] According to a preferred embodiment, the media support structure comprises a tower-like structure, preferably a conical tower-like structure, which extends axially from a proximal end at the inner surface of the cover away from the cover to a distal end.

[0142] According to a preferred embodiment, the distal end of the tower-like structure comprises an N-fold rotational symmetry about the longitudinal axis.

[0143] According to a preferred embodiment, the circumferential side wall is interrupted (or comprises one or more annular gaps) within one or more angular ranges around the longitudinal axis, or the circumferential side wall is straight.

[0144] According to a preferred embodiment, the profile of the axial end wall generally corresponds to one or more subsequent portions of a predetermined annular shape, the one or more subsequent portions being connected between adjacent annular portions via one or more chords of the annular shape, the circumferential side wall being interrupted or straight in the region corresponding to the chords (thereby defining one or more flat portions of the housing cover).

[0145] The tenth aspect of the present disclosure provides an assembly comprising: a main shell having a maintenance opening for receiving a filter element in the main shell; and a shell cover according to any embodiment of the ninth aspect, the shell cover being used to cover the maintenance opening, wherein the maintenance opening comprises an edge located in a plane inclined relative to a direction perpendicular to a longitudinal axis of the shell cover, the plane corresponding to the inclined plane of the lower edge of the shell cover.

[0146] Any embodiment and embodiment features described for any of the above aspects are also applicable to any other aspects after appropriate modification. For example, any features described for the filter element, assembly, packaging or housing cover itself are also applicable to other aspects.

[0147] For example, the location of the undercut portion within the insertion or service opening of the housing can be the same as any of the disclosed housing examples.

[0148] When the assembly is installed / used, it is advantageous to position at least one undercut portion at the bottom or lower surface of the filter maintenance opening or filter housing. Such an undercut portion requires the filter element to be lifted onto the undercut portion so that, when the filter element / filter media pack is removed, dust that may have accumulated in the air filter housing is not dislodged by the filter element / filter media pack sliding on the lower inner wall of the filter housing. Furthermore, when the assembly is installed / used, the advantage of providing an undercut portion at the bottom or lower surface of the filter maintenance opening or filter housing is that any liquid used to clean the inner wall of the housing can be contained within the housing by the undercut portion. The undercut portion located at the bottom or lower surface of the filter maintenance opening or filter housing may also advantageously include a dust discharge port or dust discharge valve.

[0149] For example, where a single undercut is provided, it may also be advantageous to locate the undercut at the filter service opening or at the top surface of the filter housing when the assembly is installed / in use. If the assembly receives the filter element in a horizontal orientation, the first end cap of the filter element may be positioned adjacent to or against the undercut, thereby holding the element in place and preventing tilting movement of the filter element downward in the housing that could otherwise break the housing seal at the second end of the filter element.

[0150] Regardless of whether only one or multiple undercuts are provided, the provision of an undercut always has the advantage that the undercut can hold the filter element in place, ie the undercut can prevent axial movement of the filter element in the housing along the housing axis. BRIEF DESCRIPTION OF THE DRAWINGS

[0151] These and other aspects of the present disclosure will be described in more detail by way of example and with reference to the accompanying drawings, in which:

[0152] Figures 1 to 3 A first preferred embodiment of the present disclosure is shown in a schematic manner.

[0153] Figures 4 to 6 A second preferred embodiment of the present disclosure is shown.

[0154] Figure 7 A variation of the second preferred embodiment is shown.

[0155] Figure 8 (a) to (c) in the drawings illustrate a third preferred embodiment of the present disclosure having an open housing sidewall and an inclined housing / cover interface. The concepts described are not limited to assemblies including the disclosed filter elements having flexible and / or resilient characteristics, but are applicable more generally.

[0156] Figure 9 The concept of a flexible first end cap is shown.

[0157] Figure 10 (a) and (b) show Figure 8 A variation of the third preferred embodiment is shown.

[0158] Figure 11 (a) to (c) show Figure 8 A variation of the third preferred embodiment is shown.

[0159] Figure 12 (a) to (c) Figure 13 and Figure 14 A fourth preferred embodiment of the present disclosure is shown.

[0160] Figure 15 and Figure 16 Variations of the fourth preferred embodiment are shown that may be used in conjunction with embodiments including a media pack support structure protruding from the inner surface of the housing cover, but are not limited thereto.

[0161] Figure 17 (a) to (c) in FIG. 5 show a fifth embodiment of the present disclosure, which does not have a medium supporting device protruding from the inner surface of the housing cover.

[0162] Figure 18 (a), (b), Figure 19 (a), (b) and Figure 20 (a) and (b) illustrate features of a housing cover for use with any embodiment of the present disclosure.

[0163] Figure 21 (a) to (c) Figure 22(a) to (c) Figure 23 (a) to (c) and Figure 24 Some examples of configurations of the first and second circumferential seals and associated sealing surfaces on the housing cover and the housing are shown.

[0164] Figure 25 (a) and (b) show examples of a locking mechanism of a housing cover used with an embodiment of the present disclosure.

[0165] Figure 26 (a) to (c) in Figures 1 and 2 illustrate further preferred embodiments of the present disclosure wherein the first and / or second end caps and their corresponding circumferential seals are inclined relative to the longitudinal axis of the filter element / filter media pack.

[0166] Figure 27 (a) to (c) in FIG. 5 show aspects of elastic deformation of a filter element end cap according to aspects of the present disclosure.

[0167] Figure 28 (a) and (b) show further preferred embodiments of the present disclosure, wherein the filter media pack is deformed by a media support structure protruding from the housing cover.

[0168] Figure 29 (a) and Figure 30 A sixth preferred embodiment of the present disclosure is shown and includes a first main filter element and a second main filter element, the second filter element not being a safety filter element, the second filter element being parallel to the first filter element and filtering the unfiltered air flow.

[0169] Figure 29 (b) in FIG. 1 shows a seventh preferred embodiment of the present disclosure.

[0170] Figure 31 (a), (b) and Figure 32 A modification of the sixth preferred embodiment of the present disclosure is shown.

[0171] Figure 33 A modification of the seventh preferred embodiment is shown.

[0172] Figure 34 (a) to (c) in FIG. 5 show modifications of the seventh preferred embodiment of the present disclosure.

[0173] Figure 35 (a) and (b) illustrate advantageous packaging associated with filter elements associated with the present disclosure.

[0174] Figure 36 A dust extraction valve is shown incorporated into the undercut portion.

[0175] Figure 37 (a) and (b) show examples of a first end cap with a manipulation device.

[0176] Figure 38 (a) shows a potential problem that arises when the distal end of the support structure is received by a groove in the circumferential seal.

[0177] Figure 38 (b) Figure 39 、 Figure 40 (a), (b), and Figure 41 (a) and (b) show other preferred embodiments of the configuration of the second circumferential seal portion and the distal end portion of the internal support structure.

[0178] Figure 42 and Figure 43 A housing and a housing cover according to an eighth preferred embodiment of the present disclosure are shown.

[0179] Figure 44 A filter element that can be used with a housing and a housing cover and a mounting process thereof according to an eighth preferred embodiment of the present disclosure are shown.

[0180] The drawings are not drawn to scale and, generally, like components are denoted by like reference numerals throughout the drawings. DETAILED DESCRIPTION

[0181] The present disclosure will be described in conjunction with specific embodiments, which are intended to illustrate the present disclosure and are not intended to be limiting. It will be understood by those skilled in the art that the present disclosure is not limited by the specific depicted and / or described content, and that alternative or modified embodiments may be developed based on the overall teachings of the present disclosure. The accompanying drawings are provided for schematic purposes only and are non-limiting.

[0182] Use of the verb "to comprise" and its conjugations does not exclude the presence of other elements than the stated elements. Use of the article "a", "an" or "the" preceding an element does not exclude the presence of a plurality of such elements.

[0183] Furthermore, the terms first, second, etc. in the specification and claims are used to distinguish similar elements and are not necessarily used to describe a temporal, spatial, or any other sequence. It should be understood that these terms are interchangeable under appropriate circumstances, and that the embodiments described herein can operate in sequences other than those described or illustrated herein.

[0184] Throughout this specification, references to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the present disclosure. Therefore, the phrases "in one embodiment" or "in an embodiment" appearing throughout this specification do not necessarily refer to the same embodiment, but may do so. Furthermore, those skilled in the art will appreciate from this disclosure that particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0185] Although many of the figures presented and discussed below are specifically directed to embodiments of filter elements for filtering air, the present disclosure is not limited thereto.

[0186] This specification refers to the main housing portion 1 and the housing cover 3, but this is a matter of choice. These portions could also be rewritten as the first housing portion 1 and the second housing portion 3. For example, when the housing cover 3 is relatively large, encompassing a substantial portion of the entire filter housing, it would be appropriate to refer to the housing cover 3 as the main housing portion 1, while the remainder of the housing could be considered the housing cover 3. In some embodiments, the main portion of the housing is the portion that includes the mounting device 112 for the air purifier.

[0187] Figures 1 to 3 A first preferred embodiment of the present disclosure is shown in a schematic manner.

[0188] The filter element 2, which includes a flexible filter media pack 20, is arranged in a tubular manner about an axis. A first open end cap 21 is connected to a first axial end 25 of the filter media pack 20 in a fluid-tight manner. A second open end cap 22 is connected to a second axial end 26 of the filter media pack 20 in a fluid-tight manner. The first end cap 21 and the second end cap 22 can be formed, for example, by a polyurethane potting process and attached to the filter media pack 20. In this case, the first circumferential seal 27 of the first end cap 21 and the second circumferential seal 28 of the second end cap 22 can be formed during the same process. The first circumferential seal 27 is a portion of the first end cap 21 that extends radially inward. The second circumferential seal 28 is a portion of the second end cap 22 and extends radially outward, for example. The two circumferential seals 27 and 28 are generally cylindrical in shape. In its undeformed state, the filter media pack 20 has a conical shape.

[0189] The first end cap 21 is flexible and can be non-destructively deformed, for example between a first shape and a second, different shape. Preferably, the first end cap 21 is elastically deformable.

[0190] The filter element 2 is arranged in a main filter housing 1 having a housing sidewall 11, a first end 15, and a second end 16. The first end 15 includes a filter insertion opening 13. The second end 16 is arranged at the end opposite the first end 15 and includes an outlet opening 121 or an outlet tube 12 having an outlet opening 121. The second end 16 also includes a sealing surface 19 that is complementary to the second circumferential seal 28 and is configured to receive the second circumferential seal 28 in a sealing manner around the outlet opening 121 when the filter element 2 is inserted into the housing 1.

[0191] The service opening 13 at the first end 15 comprises two undercut portions 14 extending radially inwardly from the side wall 11 of the housing 1 .

[0192] Since the filter element 2 is essentially conical in shape, the second end cap 22 is, for example, non-destructively deformable and can enter the maintenance opening 13 and be guided toward the second end 16 of the housing 1 for installation. However, the first end cap 21 is too large to pass through the undercut portion 14 of the insertion opening 13. Since the first end cap 21 is non-destructively deformable, for example, the first end cap 21 is elastically deformable, the first end cap 21 can be reshaped into a second shape or second state in which the first end cap 21 is smaller and can enter the maintenance opening 13. The deformation of the first end cap, for example, Figure 9 Optionally, a manipulation device or means may be provided (e.g., see Figure 37 In (a) and (b)), the manipulation device or means is, for example, a handle adapted and arranged to pull a portion of the first end cap radially inward. The manipulation device or means may include a handle bar or structure bridging opposite sides of the open end cap over a central opening in the first end cap. Alternatively, the optional manipulation device may include at least one radially inwardly directed or radially outwardly directed baffle or ear-like structure.

[0193] Once the first end cap 21 has passed through the service opening 14, it returns to its original shape and is partially positioned below the undercut 14 and in the sub-volume 131 of the inner volume of the filter housing 1. It can be noted that the projection of the filter element 2 along the housing axis intersects with the projection of the undercut 14 along the housing axis, the intersection corresponding to the overlapping area of ​​the projections.

[0194] Shell cover 3 ( Figure 3) is configured to close the insertion or maintenance opening 13 of the housing. The housing cover 3 includes an internal filter media pack support structure 31, such as a tower-like structure 31, preferably having a conical shape, that protrudes from a proximal end toward a distal end at the inner surface 301. The tower-like structure 31 is essentially open and may include ribs or a lattice structure 32. The tower-like structure 31 may serve as an internal lining for the filter media pack 20. When the cover 3 is mounted on the main housing 1, the proximal end of the tower-like structure 31 is closed and forms a sealing surface 37 for the first circumferential seal 27. In this case, the cover 3 also covers the undercut portion 14 of the maintenance opening 13.

[0195] The housing further comprises an inlet 17. For example, one or more inlet openings may be provided in the side wall 11 of the housing 1 .

[0196] Figures 4 to 6 The second preferred embodiment of the present disclosure is shown and is very similar to the first preferred embodiment. The second preferred embodiment includes a housing inlet pipe arranged to allow air to be filtered to enter the filter housing perpendicular to the housing and filter axis. The air then passes through the filter media pack 20 into the interior volume of the filter and exits the air purifier through the outlet opening 12. Two diametrically opposed undercuts 14 are provided at the service opening 13.

[0197] At least one of the undercut portions 14 includes an alignment feature 141 for aligning with a corresponding alignment feature on the cover 3. A plurality of closure devices or means, such as latches 302, are provided on the outer surface 300 of the housing cover 3 for locking the cover 3 to the main housing 1. The latches 302 on the cover 3 are adapted to lock behind the locking features 18 arranged on the side wall 11 of the main housing 1 at corresponding positions. The first circumferential seal 27 seals against one or more sealing surfaces 37 on the inner surface 301 of the housing cover.

[0198] Preferably, one of the closure devices, such as latch 302, is positioned on or adjacent to flat portion 3F, and interacts with a corresponding portion of the housing adjacent to undercut 14, preferably adjacent to or below flat portion 14F. Other closure devices may also be used, such as, for example, finger locks, rubber bands, clips, bolts, and nuts.

[0199] Figure 7A variation of the second preferred embodiment is shown. The air purifier includes an additional element 4 for interacting with the fluid or air flow, such as a safety filter element or a chemical filter element. The additional element 4 is arranged within the media pack support structure or tower 31 and extends partially from the second end 16 of the housing toward the first end 15. The additional element 4 may, for example, include a radially outwardly oriented circumferential seal for sealing against the inner sealing surface of the outlet pipe 12.

[0200] Figure 8 1 and 2 illustrate a third preferred embodiment of the present disclosure, which is similar to the previous preferred embodiments but includes an angled housing / cover interface S. The concepts described are not limited to assemblies including the disclosed filter elements having flexible and / or resilient characteristics, but are more generally applicable to filter elements 2 capable of non-destructive deformation. Furthermore, the housing cover 3 includes a single flat portion 3F that complements the single undercut portion 14 of the service opening 13.

[0201] The housing cover 3 and the filter housing 1 are adapted so that the housing cover 3 and the filter housing 1 meet along an inclined plane S which causes the housing length L of the main housing 1 at the side corresponding to the undercut 14 to be greater than the housing length L at the opposite side of the housing. This has the advantage that, before the filter element 2 is removed from the service opening 13 of the main housing 1 or before the filter element 2 is inserted into the service opening 13 of the main housing 1, the filter element 2 can be tilted somewhat, for example, to move the filter element 2 away from the undercut 14, which allows the use of a filter element 2 having a relatively undeformable or non-deformable first end cap 21, or the use of an element which is capable of a relatively large degree of deformation.

[0202] The housing cover 3 includes an axial end wall 30e connected to a circumferential side wall 30 arranged around the longitudinal axis, and a lower edge 30r of the side wall 30 surrounding the filter housing engagement opening. The lower edge 30r is defined by a plane inclined relative to a direction perpendicular to the longitudinal axis.

[0203] The axial end wall 30e of the cover 3 is arranged perpendicular to the longitudinal axis, and the circumferential side wall 30 extends between a minimum width and a maximum width, the minimum width being located at the minimum axial distance between the lower edge 30r and the axial end wall 30e, and the maximum width being located at the maximum axial distance between the lower edge 30r and the axial end wall 30e.

[0204] The profile of the axial end wall 30e of the housing cover 3 (or the projection of the axial end wall 30e of the housing cover 3 on a plane perpendicular to the axis) corresponds to a portion (or multiple consecutive portions) of a predetermined annular shape, with adjacent annular portions connected via one (or more) chord lines of the annular shape, and the circumferential side wall 30 is interrupted or straight in the area corresponding to the chord lines. The interrupted or straight portion corresponds to the flat portion 3F. When the cover 3 is placed on the main housing 1, the undercut portion 14 (e.g., the straight chord surface 14F of the undercut portion 14) and the flat portion 3F of the cover 3 serve as alignment features between the cover 3 and the main housing 1 because the cover 3 and the main housing 1 abut against each other.

[0205] The service opening of the main housing comprises an edge 1311 lying in a plane inclined relative to a direction perpendicular to the longitudinal axis of the housing or housing cover and corresponding to the inclined plane of the lower edge 30 r of the housing cover 3 .

[0206] Figure 10 (a) and (b) show Figure 8 A variation of the third preferred embodiment is shown, which includes an open housing side wall 11 having a lattice structure. Preferably, the side wall includes openings 111 separated by flow guide vanes or fins 110 (the openings 111 serve as inlets; alternatively, the side wall may be a closed side wall with a separate inlet opening). This variation also includes a latch connection arranged on an undercut portion 14 toward the housing cover 3, and the housing cover 3 includes a capture surface adjacent to the flat portion 3F for latching (or vice versa). The undercut portion 14 is positioned at a side of the housing mounting device 112 that is generally more difficult to access during maintenance. The advantage is that the latch located on the undercut portion 14 is easier to access during maintenance than a latch mounted on the side wall 11 of the housing at the side of the housing mounting device 112.

[0207] Figure 11 (a) to (c) show Figure 8 The variation of the third preferred embodiment shown, which also has a closed housing side wall 11 of the housing 1, includes a latching and capturing surface connection between the side wall 30 of the housing cover 3 and the main housing side wall 11.

[0208] Figure 12 (a) to (c) Figure 13 and Figure 14 The fourth preferred embodiment of the present disclosure is shown, which is similar to the third preferred embodiment and its variations are combined Figure 8 、 Figure 10 and Figure 11 It was made public.

[0209] According to the fourth preferred embodiment, when the filter element 2 is mounted in the main housing 1 and the main housing 1 is closed by the cover 3 , the distal end 303 of the support means or tower 31 of the cover 3 interacts with the second circumferential seal 28 of the filter element 2 .

[0210] The filter element 2 includes a (preferably, but not necessarily, flexible) filter media pack 20 arranged in a tubular manner about an axis; a first open end cap 21 connected in a fluid-tight manner to a first axial end 25 of the filter media pack 20; and a second open end cap 22 connected in a fluid-tight manner to a second axial end 26 of the filter media pack 20. The filter element 2 and the media pack 20 are tapered. The cross-section of the filter media pack taper decreases from the first axial end 25 of the media pack to the second axial end 26 of the media pack 20. The outer diameter of the second end cap 22 is smaller than the outer diameter of the first end cap 21.

[0211] The second open end cap 22 includes a central opening and a second circumferential seal 28. The second circumferential seal 28 comprises a portion of the second end cap 22 that extends radially inwardly into the central opening. The radially inwardly extending portion includes at least one circumferential groove, channel, or recess 281 (e.g., in a U- or V-shape) disposed adjacent to the central opening. The groove, channel, or recess protrudes into the interior volume of the filter media pack 20 (or the interior volume of the filter element), e.g., in a direction parallel to the axis of the filter media pack 20 or the filter element 2.

[0212] The filter housing comprises a first end 15 comprising the filter insertion opening 13 and adapted to receive the cover 3 having the towers 31, and a second end 16. The second end 16 is arranged at the end opposite the first end 15 and comprises an outlet opening 121. The second end 16 further comprises a sealing surface 19 complementary to the second circumferential seal 28 for receiving the second circumferential seal 28 in a sealing manner when the filter element 2 is correctly mounted in the housing.

[0213] For purposes of this disclosure, the terms inlet and outlet refer to openings in the housing through which air flows "from the inlet to the outlet." Those skilled in the art will appreciate that, in certain assembly configurations, reverse flow may be employed, wherein the flow may flow in the reverse direction from the outlet to the inlet. This does not affect the essence of the inventive concept of this disclosure.

[0214] The distal end 303 of the support structure 31 is arranged and adapted to be received by an axially extending circumferential groove, groove or recess 281 of the second circumferential seal 28 of the filter element 2, so as to provide a radially outward back pressure to the circumferential seal 28 toward the sealing surface 19 of the filter housing 1 when the cover 3 is mounted on the housing 1.

[0215] Figure 15 and Figure 16 Variations of the fourth preferred embodiment are shown that may be used in conjunction with embodiments including a media pack support structure 31 protruding from an inner surface 301 of the housing cover 3 , but are not limited thereto.

[0216] exist Figure 15 In the illustrated embodiment, the distal end portion 303 of the support structure 31 includes at least one radially inwardly protruding protrusion 303r, which corresponds to the at least one radially inwardly protruding protrusion 28r of the second circumferential sealing portion 28 and to the at least one radially inwardly protruding protrusion 19r of the second circumferential sealing surface portion 19.

[0217] exist Figure 16 In the illustrated embodiment, the distal end portion 303 of the support structure 31 includes at least one axially inwardly protruding protrusion 303s, which corresponds to the at least one axially inwardly protruding protrusion 28s of the second circumferential sealing portion 28 and to the at least one axially inwardly protruding protrusion 19s of the second circumferential sealing surface portion 19.

[0218] Figure 15 and Figure 16 The embodiment allows a rotational locking of the filter element and a predetermined clockwise or angular orientation of the filter element 2 within the housing 1 .

[0219] In other embodiments, no support structure or tower 31 is provided. Figures 12 to 16 The described interaction of the support structure or the distal end of the tower 31 can, for example, be replaced by a similar interaction between a separate mounting device (not shown) that is inserted into at least one circumferential (e.g. U-shaped or V-shaped) groove, slot or recess 281 and performs the same function as the distal end 303. This mounting device can, for example, generally comprise an annular structure and can have radially and axially inwardly projecting protrusions similar to the distal end of the tower 31. This also applies to Figure 44 The embodiment described in .

[0220] Figure 17(a) to (c) in the figure show a fifth preferred embodiment of the present disclosure, which does not include a media support device protruding from the inner surface of the housing cover. As long as it does not involve the arrangement of the media support device or the tower 31 and the possible interaction between the tower (the distal end 303) and the second circumferential seal, this embodiment is similar to all previous embodiments. In fact, when the filter element 2 does not include flexible or elastically deformable parts such as for the first end cap 21, the media pack 20 and the second end cap 22, the interaction between the main housing 1, the housing cover 3 and the filter element 2 has the same advantages, for example, involving an inclined joint S between the housing cover 3 and the main housing 1, and an undercut portion 14 in the housing inlet opening 13 and a complementary flat surface 3F on the housing cover 3.

[0221] Figure 18 (a), (b), Figure 19 (a), (b), and Figure 20 (a) and (b) illustrate features of a housing cover for use with any embodiment of the present disclosure.

[0222] Figure 18 (b) shows that the housing cover 3 can be flat. The housing cover 3 can also include a disclosed flat portion 3F (interrupted or straight) for alignment and other disclosed purposes.

[0223] Figure 18 (a) shows an example of combining Figure 8 、 Figures 10 to 12 and Figure 17 The disclosed housing cover 3 includes an upper or outer surface 300 oriented along a plane P1 perpendicular to the housing cover axis. The lower edge 30r of the side wall 30 of the housing cover 3 is arranged along a second plane P2, which is inclined relative to a plane perpendicular to the housing cover axis. The angle α between the two planes can be, for example, between 10° and 45°, and more preferably, between 5° and 30°.

[0224] Figure 19 (a) in FIG. 1 shows a top view of a housing cover 3 according to an embodiment of the present disclosure, the housing cover 3 having a single flat portion 3F. A virtual supplementary portion 14* of the housing cover is marked with a dotted line, the virtual supplementary portion 14* corresponding to the undercut portion 14 in the relevant housing.

[0225] Figure 19(b) is a top view of a housing cover 3 according to an embodiment of the present disclosure, having two flat portions 3F and 3F'. Virtual complementary portions 14* and 14*' of the housing cover are marked with dashed lines and correspond to undercut portions 14 and 14', respectively, in the corresponding housing. Flat portions 3F and 3F' may be parallel, or they may be at an angle β.

[0226] Figure 20 A preferred configuration for the disclosed housing cover 3 and filter assembly is shown, wherein a sensor port 5 is arranged centrally in the housing cover 3, the sensor port 5 having, for example, a pressure sensor 50 and an associated small opening toward the clean side of the filter assembly. Advantageously, the pressure sensor can be visually inspected on the service side of the housing 1 due to the provision of access to the clean side.

[0227] Figures 21 to 24 Some examples of configurations of first and second circumferential seals and associated sealing surfaces on the housing cover and housing are shown.

[0228] One or both of the first circumferential seal portion 27 and the second circumferential seal portion 28 may have a rotationally symmetrical profile, or one or both of the first circumferential seal portion 27 and the second circumferential seal portion 28 may include non-rotational symmetry. The same applies to their corresponding sealing surfaces 37 and 19.

[0229] For example, the circumferential seals 27 and 28 and their corresponding sealing surfaces 19 and 37 can be suitable for rotational positioning and locking of the filter element relative to the housing or relative to the housing cover.

[0230] For example, Figure 21 As shown in (a) and (b), the first circumferential seal portion 27 and the corresponding sealing surface 37 may comprise a gear-type configuration, such as described in European Patent No. EP 3413993. The second circumferential seal portion 28 may be, for example, a rotationally symmetrical radially (inwardly or outwardly) directed seal portion for sealing against the cylindrical second circumferential sealing surface portion 19.

[0231] Figure 21 (c) shows another embodiment in which the first circumferential seal portion 27 comprises a rotationally symmetrical radially (inwardly or outwardly) directed seal portion for sealing against the cylindrical first circumferential sealing surface portion 37. The second circumferential seal portion 28 may comprise an inwardly directed gear-like configuration, such as described in EP 3413993. The second circumferential sealing surface portion 19 may have a corresponding outwardly directed gear-like structure, such as described in EP 3413993.

[0232] For example, Figure 22 As shown in (a) and (b) of the drawings, the first circumferential sealing portion 27 and the corresponding sealing surface 37 may comprise a flower-shaped configuration, such as that described in European Patent No. EP 2771092. The second circumferential sealing portion 28 may be, for example, a rotationally symmetrical radially (inwardly or outwardly) directed sealing portion for sealing against the cylindrical second circumferential sealing surface portion 19.

[0233] Figure 22 (c) shows another embodiment in which the first circumferential seal portion 27 comprises a rotationally symmetrical radial (inward or outward) seal portion for sealing against the cylindrical first circumferential seal surface portion 37. The second circumferential seal portion 28 may comprise an inwardly directed flower-shaped configuration, such as described in EP 2771092. The second circumferential seal surface portion 19 may have a corresponding outwardly directed gear-like configuration, such as described in EP 277109.

[0234] Figure 23 (a) and (b) disclose further embodiments in which the first circumferential sealing portion 27 and the corresponding first circumferential sealing surface portion 37 are elliptical. The second circumferential sealing portion 28 can, for example, be a rotationally symmetrical radially (inwardly or outwardly) directed sealing portion for sealing against the cylindrical second circumferential sealing surface portion 19.

[0235] Figure 23 (c) shows another embodiment, in which the first circumferential sealing portion 27 comprises a rotationally symmetrical radially (inwardly or outwardly) directed sealing portion for sealing against the cylindrical first circumferential sealing surface portion 37. The second circumferential sealing portion 28 may be, for example, a radially (inwardly or outwardly) directed elliptical sealing portion for sealing against the corresponding elliptical second circumferential sealing surface portion 19.

[0236] Figure 24 is a projection diagram of another embodiment of the present disclosure, which is to some extent Figure 23 A combination of embodiments (a), (b), and (c) in which both the first circumferential seal portion 27 and the second circumferential seal portion 28 are elliptical and seal against respective elliptical sealing surfaces 37, 19. The elliptical shape may have major axes that are at an angle of, for example, 90° or at an angle between 15° and 19°.

[0237] Generally, it is advantageous for the first sealing portion 27 and the second sealing portion 28 to have different shapes, for example in combination with Figures 21 to 23 The example described above is as this will allow the user to install the cone in the correct direction. Installing the cone in the opposite direction may damage the filter element.

[0238] Other combinations of the disclosed first and second circumferential seals 27 , 28 and their corresponding sealing surfaces 37 , 19 are contemplated and considered disclosed.

[0239] In an embodiment in which the first circumferential seal and the second circumferential seal each have a corresponding rotational locking function relative to the longitudinal axis of the filter element or filter housing and the filter media pack 20 of the filter element is flexible, an advantageous configuration of the filter assembly is provided in which the tubular filter media pack is twisted so that the internal volume of each housing contains relatively more media. This configuration of the assembly can be achieved in the following way. The second circumferential seal 28 and therefore the second end cap 22 can be inserted into the housing 1 in a fixed / locked angular position relative to the housing 1 (for example, relative to the housing outlet 12). The filter element is longer than the housing cavity and protrudes from the maintenance opening 13. The first circumferential seal 27 is then connected to the sealing surface 37 of the housing cover 3 in a fixed / locked angular position relative to the cover 3. The one or more flat portions 3F, 3F' of the cover 3 and the one or more complementary undercut portions 14, 14' of the housing inlet 13 can then be aligned by rotating the cover relative to the housing through a predetermined angle, thereby twisting the media pack 20 in a predetermined manner and shortening the media pack 20 so that the filter element 2 fits into the housing cavity again and the housing cover can be closed. Figure 25 It is shown schematically in FIG. Figure 25 Also shown is an example of a locking mechanism 333 of the housing cover 3 to the housing 1 for use with embodiments of the present disclosure, which locking mechanism may be, for example, of the bayonet type or any other prior art type.

[0240] Figure 26 (a) to (c) show further preferred embodiments of the filter element of the present disclosure, wherein the first end cap 21 and / or the second end cap 22 and their corresponding circumferential seals 27, 28 are inclined relative to a plane perpendicular to the longitudinal axis of the filter element 2 / filter media pack 20.

[0241] exist Figure 26 In (a) and (b), the second end cap 22 is perpendicular to the filter axis, while the first end cap 21 is inclined relative to a plane perpendicular to the longitudinal axis. The respective circumferential seals 27, 28 are oriented along the plane defined by the end caps 21, 22.

[0242] exist Figure 26 In (c), both the first end cap 21 and the second end cap 22 are inclined relative to a plane perpendicular to the longitudinal axis. The respective circumferential seals 27, 28 are oriented along the plane defined by the end caps 21, 22.

[0243] Figure 27(a) to (c) in the drawings illustrate aspects of the elastic deformation of the first end cap 21 of the filter element according to aspects of the present disclosure in projected views along the axis of the filter element. The filter media pack and the first circumferential seal 27 and the central opening of the filter media pack 20 are elliptical. The maintenance opening 13 is elliptical, but the first end cap 21 cannot pass through the inlet opening 13 without deformation, primarily due to the two undercut portions 14, 14' provided on opposite sides of the maintenance opening. Figure 27 In (b), the first end cap 21 (including the first circumferential seal 27) and the media pack are elastically deformed so that the second end cap 21 can pass through the maintenance opening in the deformed state. Figure 27 In (c) the filter element 2 has passed through the service opening 13 and has elastically returned to its original configuration and occupies the space below the undercuts 14, 14'.

[0244] Figure 28 (a) and (b) in the figure show another preferred embodiment of the present disclosure, in which the filter media pack 20 is deformed by a media support structure 31 protruding from the housing cover 3. The filter element 2 is elastically deformable and has a cylindrical or conical shape. The filter element 2 is inserted into the filter housing 1, and the side walls of the filter housing have different shapes (for example, a constant cross-section, projected as a D-shape). The maintenance opening 13 has, for example, the same shape as the cross-section of the housing. The elastically deformable filter element 2 is inserted into the housing 1 and its deformation is guided by the maintenance opening and the side walls of the housing. After installation, the elastically deformable filter element 2 has been adjusted or has assumed the shape of the filter housing volume. Then, when the housing cover 3 is placed on the housing 1, the filter media support device or tower-shaped member protruding from the housing cover 3 is inserted into the interior of the filter media pack 20 to support the filter media pack 20 from the inside.

[0245] Figure 29 (a) and Figure 30A sixth preferred embodiment of the present disclosure is shown, comprising a first main filter element 2 and a second main filter element 6, the second main filter element 6 not being a safety filter element, being parallel to the first filter element 2 and filtering the unfiltered air flow. The cover 3 includes a second circumferential sealing surface portion 37' arranged on the inner surface 301 for receiving another circumferential sealing portion 67 of the second filter element 6, the second circumferential sealing surface portion 37' being arranged radially within the first circumferential sealing surface portion 37. The cover also includes one or more inlet openings O3A, for example, centrally located in an axial end wall of the housing cover 3, the inlet openings O3A being arranged radially within the second circumferential sealing surface portion 67. The second filter element is, for example, conical in shape and comprises a tubular arrangement or pleated media, and has closed end caps on opposite sides of the sealing portion 67. Air entering opening O3A is subsequently filtered by the second filter element 6 before entering the clean air side of the first filter element and exiting the filter assembly through outlet 12 .

[0246] Figure 31 (a), (b) and Figure 32 A modification of the sixth preferred embodiment of the present disclosure is shown. Figure 31 In (a) and (b), a second filter element 6 is provided, comprising fluted media type media 60, such as wound fluted media. The cover includes an inlet opening O3A centrally located in the axial end wall of the housing cover 3, radially within the second circumferential sealing surface portion 67. Air entering opening O3A is subsequently filtered by the second fluted filter element 6, enters the clean air side of the first filter element 2, and exits the filter assembly through outlet 12. Figure 32 A variation is shown in which the inlet opening O3A further comprises a vane or waffle arrangement O3AW comprising air flow guiding ribs which allow for improved uniformity of the incoming air flow. The flow guiding ribs are preferably parallel to the axis of the trough media pack 60.

[0247] Figure 29 (b) shows a seventh preferred embodiment of the present disclosure. The cover 3 includes one or more outlet openings O3B, for example, centrally located in the axial end wall, radially inside the first circumferential sealing surface portion 37 and the first circumferential sealing portion 27. The outlet openings O3B thus form a second outlet 12' for clean air from the housing 1, which can be directed to a second air consumer, such as a compressor.

[0248] Figure 33 A variant of the seventh preferred embodiment is shown, in which a centrally located second outlet opening O3B is provided. The outlet opening O3B may for example be a part of the second outlet pipe of the housing 1 (located in the outlet cover 3).

[0249] Figure 34 (a) to (c) in FIG. 5 show variations of the seventh preferred embodiment of the present disclosure. Figure 33 , a variation of the seventh preferred embodiment includes a single, centrally positioned second outlet O3B. In addition, a variation of the seventh preferred embodiment also includes a group of openings 33t located on the housing cover 3, which are circumferentially distributed on the peripheral area of ​​the housing cover 3 and radially outside the first circumferential sealing surface portion 37. One or more or all of the openings 33t in the group extend from the axial end surface of the housing cover to the radial side wall 30 of the housing cover 3. These openings then serve as additional air inlets for the filter assembly. The radial side wall 30 of the housing cover 3 may also include openings 33, which are optionally defined in a grid structure, the openings being located, for example, between flow guiding devices or means 34 such as ribs, fins or blades, the openings also serving as inlets, as described above.

[0250] Figure 38 (b) Figure 39 、 Figure 40 (a), (b) and Figure 41 (a) and (b) show, for example, the Figure 16 and Figures 30 to 31 An alternative configuration of the interaction of the distal end 303 of the internal support structure or tower 31 with the circumferential groove, channel or recess 281 in the associated described embodiments.

[0251] Figure 38 (a) in the figure illustrates a potential problem that occurs when the distal end portion of the support structure is received by the groove in the circumferential seal portion 28. When the groove 281 in the seal portion 28 includes local deformation and / or when the distal end portion 303 of the support structure 31 is not fully aligned with the groove 28 when inserted, the distal end portion 303 may push against the seal portion 28 at a location adjacent to the groove 281, which typically results in deformation of the seal portion 28 such that the groove 281 is at least partially deformed or closed, and the distal end portion 303 cannot be received by the groove 281.

[0252] Figure 38(b) in FIG. 2 shows a groove 281 having a radially inner sidewall 2813 and a radially outer sidewall 2812 connected by a bottom wall 2815. The radially outer sidewall 2812 includes a beveled portion or chamfered portion or surface 2814 adjacent to the opening of the groove 281, thereby widening the groove 281 adjacent to the opening of the groove 281. The beveled portion of the surface 2814 simplifies the positioning and / or reception of the distal end 303 of the internal support structure 31 through the groove 281. Preferably, at a level below the beveled portion 2814, the width of the groove is between 2 mm and 10 mm, or the width of the groove is between 3 mm and 8 mm. At the opening of the groove 281, the width of the groove 281 can be increased by approximately 1 mm to 6 mm, or the width of the groove 281 can be increased by approximately 3 mm to 5 mm due to the beveled portion or surface 2814. The chamfered portion 2814 preferably forms an angle with the radially inner sidewall 2813 in the range of 10° to 45°. In addition to the chamfered portion 2814, a smaller angle may be formed between the non-beveled portion of the radially inner sidewall 2813 and the radially outer sidewall 2812, meaning that the radially inner sidewall 2813 and the radially outer sidewall 2812 are not completely parallel. For example, the angle between the non-beveled portion of the radially inner sidewall 2813 and the radially outer sidewall 2812 may be 0° to 10°, preferably 1° to 7°, or for example 2°. The depth of the circumferential groove 281 may be, for example, in the range of 5 mm to 40 mm, or 10 mm to 40 mm.

[0253] In some cases, it has been discovered that when distal portion 303 of internal support structure 31 is received in the cavity formed by sidewalls (2812, 2813, 2815) of groove 281 and distal portion 303 of internal support structure 31, a closed air pocket may form in groove 281. During reception, this air pocket may cause resistance to the insertion process. Furthermore, during removal, this air pocket may hinder the removal of internal support structure 31 because it may generate negative pressure during the removal process. Figure 39 An embodiment that solves the above problem is shown. The radially outer sidewall 2812 (or the radially inner sidewall 2813) is provided with one, two or more axially extending fluid communication channels 2811. These channels preferably connect the cavity formed by the sidewalls 2812, 2813, 2815 of the groove 281 and the distal end 303 of the internal support structure 31 to the internal volume of the filter element 2.

[0254] Figure 40(a) and (b) in the drawings show a groove 281 having a radially inner sidewall 2813 and a radially outer sidewall 2812 connected by a bottom wall 2815. The radially outer sidewall 2812 may include a chamfered portion or surface 2814 adjacent to the opening of the groove 281, as described above. The second circumferential seal portion 28 also includes a plurality of spacer ribs 2816, preferably regularly spaced apart, which bridge the radially inner sidewall 2813 and the radially outer sidewall 2812, preferably by connecting the radially inner sidewall 2813 and the radially outer sidewall 2812 in a direction perpendicular to the circumferential direction of the groove 281. This has the advantage of making the groove width more constant. As a result, in the groove 281, recesses 2817 are formed between adjacent spacer ribs 2816. These pockets 2817 can receive distal axial extensions 3031 ("teeth") of the distal portion 303 of the associated internal support structure 31. Viewed from another perspective, the distal portion 303 can include a series of regularly spaced axial cuts that receive the spacer ribs 2816 when the internal support structure 31 is received by the groove 281 in one of a plurality of relative angular alignment positions.

[0255] Figure 41 (a) and (b) show Figure 40 A variation of the embodiments of (a) and (b) in which only a single relative angular alignment position can be set between the internal support structure 31 and the groove 281.

[0256] exist Figure 41 In (a), one of the preferably regularly spaced recesses 2817' is deeper than the others and is disposed in an axially extending portion 2819 of the circumferential seal portion 28. The recess 2817' can receive a corresponding tooth 3031' that is longer than the other teeth 3031 of the distal portion 303. The internal support structure 31 is properly received by the groove 281 only when the longer tooth 3031' is aligned with the deeper recess.

[0257] exist Figure 41 In (b), the portion of the sealing portion 28 corresponding to one of the plurality of preferably regularly spaced recesses 2817 does not include recess 2817 (or includes a closed recess). The distal end portion 303 lacks the corresponding tooth portion 3031 (gap 3032). Only when the position of the closed recess aligns with the position of the gap 3032 can the internal support structure 31 be properly received by the groove 281.

[0258] Figure 35Advantageous packaging associated with the filter element 2 associated with the present disclosure is shown. The elastically deformable filter element 2 can be maintained in a deformed state within a packaging container 9, such as a (cardboard) box, bag or sleeve. The elastically deformable filter element 2 can also be maintained in a deformed state by a retaining device (not depicted) and then inserted into the packaging container 9. For example, before the elastically deformable filter element 2 is inserted into the packaging container 9 through the insertion opening 90, the elastically deformable filter element 2 can be maintained in a deformed state by an elastic or non-elastic rope or strap. In a preferred embodiment, the packaging container 9 is sufficiently strong and suitable for deforming all or part of the filter element 2 (such as any option among the first end cap 21, the filter media pack 20, the second end cap 22) when the filter element 2 is inserted into the packaging container 9.

[0259] Figure 36 The dust extraction valve 3V is shown incorporated into at least one undercut portion 14. In this case, the undercut portion 14 is positioned at the lower end of the housing inlet opening when the air filter housing is in use.

[0260] Figure 37 (a) and (b) show examples of the first end cap having a manipulation device.

[0261] Figure 37 (a) shows an embodiment in which a protruding structure 270 surrounds a central opening of the first end cap and supports or forms a first circumferential radial seal 27 that is preferably directed inwardly, the protruding structure 270 also including a handle portion 271 extending radially outwardly from the remainder of the structure 270, the handle portion being shaped to be grasped by an adult's fingers.

[0262] Figure 37 (b) shows another embodiment in which a protruding structure 270 surrounds the central opening of the first end cap and supports or forms, for example, a first circumferential radial seal 27 directed inwardly. The protruding structure 270 further includes a radially extending baffle 275 that extends parallel to the outer surface of the first end cap 21, for example, having parallel exposed surfaces 273. The baffle 275 includes one or two hook-shaped portions 274 that are adapted to hook behind a rib or fin 14r arranged on the housing. Preferably, the rib or fin 14r is arranged on the undercut portion 14, for example, the rib or fin 14r is parallel to the flat portion 14F.

[0263] Figure 42 and Figure 43 A filter assembly according to an eighth preferred embodiment of the present disclosure is shown, the filter assembly comprising a main housing 1 and a housing cover 3 . Figure 44 Possible associated filter elements are shown.

[0264] The housing cover 3 includes an axial end wall 30e connected to a circumferential side wall 30 arranged around the longitudinal axis. The housing cover 3 defines a lower edge 30r' of the side wall 30, which surrounds the filter housing engagement opening. The lower edge 30r' is at least partially or completely defined by a plane that is inclined relative to a direction perpendicular to the longitudinal axis.

[0265] The axial end wall is arranged perpendicular to the longitudinal axis, and the circumferential side wall extends between a minimum width and a maximum width, wherein the minimum width is located at the minimum axial distance between the lower edge 30r' and the axial end wall 30e, and the maximum width is located at the maximum axial distance between the lower edge 30r' and the axial end wall 30e.

[0266] The housing cover sidewall 30 comprises one or more housing cover sidewall openings 33 which may serve as housing inlet, for example being embodied as a grid structure 32 comprising flow guide vanes 34 and / or ribs.

[0267] The housing cover 3 also includes a filter media or outer support structure 35 that protrudes axially from the inner surface starting from the axial end wall 30e. The media support structure 35 comprises a tower-like structure that extends axially from a proximal end at the inner surface of the cover 3 and away from the cover 3 to a distal end 351. The media support structure 35 comprises a lattice structure defined by openings 352 and ribs 353. For example, the media support structure 35 can provide media support on the outer side of the filter media pack 20.

[0268] The axial length of the housing cover 3 including the media support structure 35 is greater than the axial length of the complementary main housing 1 .

[0269] The main housing 1 includes a service opening for receiving the filter element 2 in the main housing 1, an outlet 12, and mounting means 112. The service opening includes an edge 1311 that lies in a plane that is inclined relative to a direction perpendicular to the longitudinal axis of the main housing 1, which plane corresponds to the inclined plane of the lower edge 30r' of the housing cover 3. The side wall of the main housing 1 includes one or more housing side wall openings 111 that can serve as a housing inlet, for example, being embodied as a grid structure including flow guide blades or ribs 110.

[0270] The main housing 1 also includes a media support structure or tower 113 adjacent to and surrounding the filter housing outlet 12 and projecting into the interior volume of the air cleaner. The tower 113 is arranged and adapted to support the filter media pack 20 from within.

[0271] Figure 44 Shown are a filter element 2 used together with a housing 1 and a housing cover 3 and an installation process thereof according to an eighth preferred embodiment of the present disclosure.

[0272] and Figures 12 to 16 、 Figures 30 to 31 and Figures 38 to 41 In contrast to the configuration of the related embodiment in which the second circumferential seal portion 28 is configured to seal in the radially inward direction, Figure 44 The filter element 2 is configured to seal in the radially outward direction.

[0273] The second end cap 22 of the filter element 2 includes a portion of a second circumferential seal 28 disposed at the outer periphery of the second end cap 22 and the filter media 20. The circumferential seal 28 extends radially outward from the media pack 20 and forms a circumferential groove, recess, or recess 281 that projects toward the first end cap 21, preferably in a direction parallel to the outer wall of the filter media 20.

[0274] When the filter element 2 is installed in the main housing 1, the seal portion 28 contacts the corresponding sealing surface 19 in the main filter housing 1. When the housing cover is installed, the distal end 351 of the outer support structure 35 is received in the groove 281. The groove 281 and the distal end 351 are also configured so as to provide back pressure on the seal 28, thereby improving and securing the seal between the seal portion 28 and the sealing surface 19.

[0275] Similar improvements can be applied to the groove 281 and / or the distal end portion 351, as described in the embodiment in which the sealing direction of the second circumferential seal portion 28 is radially inward, with necessary changes. For example, the side surface of the groove 281 (here, the radially outward surface) can include a chamfered portion.

[0276] Example aspects

[0277] For example, the following may be required:

[0278] 1. A filter element comprising: a flexible filter media pack arranged in a tubular manner about an axis; a first open end cap connected to a first axial end of the filter media pack in a fluid-tight manner; and a second open end cap connected to a second axial end of the filter media pack in a fluid-tight manner, wherein the first end cap is flexible and can be non-destructively deformed between a first shape and a different second shape.

[0279] 2. The filter element according to item 1, wherein the minimum radial cross-sectional dimension of the second shape of the first open end cap is at least 5% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the first open end cap is at least 10% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the first open end cap is at least 15% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the first open end cap is at least 20% smaller than the minimum radial cross-sectional dimension of the first shape; or, the second shape of the first open end cap is at least 10% smaller than the minimum radial cross-sectional dimension of the first shape; The minimum radial cross-sectional dimension of the second shape of the first open end cover is at least 25% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the first open end cover is at least 30% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the first open end cover is at least 40% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the first open end cover is at least 50% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the first open end cover is at least 75% smaller than the minimum radial cross-sectional dimension of the first shape.

[0280] 3. The filter element according to item 1 or 2, wherein the first end cap is elastically deformable.

[0281] 4. The filter element according to any of the preceding items, wherein the first end cap is connected to the filter medium and can be manufactured by potting.

[0282] 5. The filter element of any of the preceding items, wherein the first end cap comprises a first circumferential seal, preferably the first circumferential seal being integrally formed with the first end cap.

[0283] 6. The filter element of item 5, wherein the first circumferential seal comprises an N-fold rotational symmetry relative to the axis of the filter media pack, for example, the first circumferential seal comprises a 1-fold rotational symmetry relative to the axis of the filter media pack.

[0284] 7. The filter element of clause 5 or 6, wherein the first circumferential seal is arranged along an inclined plane relative to a plane perpendicular to the axis of the filter media pack.

[0285] 8. The filter element according to any of the preceding items, wherein the first end cap is deformable in radial direction by a radial force component of less than 40N.

[0286] 9. The filter element according to any of the preceding items, wherein the first end cap further comprises at least one manipulation means, such as a handle, adapted and arranged to pull a portion of the first end cap radially inwards.

[0287] 10. The filter element of clause 9, wherein the manipulation means comprises a handle bar or structure bridging opposite sides of an open end cap over a central opening in the first end cap.

[0288] 11. The filter element according to any one of claims 9 or 10, wherein the steering means comprises at least one baffle or ear-like structure pointing radially inwardly or radially outwardly.

[0289] 12. A filter element according to any of the preceding items, wherein the filter media pack is of a conical type, i.e., the filter media pack is arranged in a conical manner, wherein the cross-section of the respective conical piece decreases from the first axial end of the media pack to the second axial end of the media pack, and wherein the second end cover has a smaller outer diameter than the first end cover.

[0290] 13. The filter element of any of the preceding items, wherein the second end cap is flexible and the second end cap is non-destructively deformable between a first shape and a second, different shape.

[0291] 14. The filter element of any of the preceding items, wherein the minimum radial cross-sectional dimension of the second shape of the second open end cap is at least 5% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cap is at least 10% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cap is at least 15% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cap is at least 20% smaller than the minimum radial cross-sectional dimension of the first shape; or The minimum radial cross-sectional dimension of the second shape is at least 25% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cover is at least 30% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cover is at least 40% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cover is at least 50% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cover is at least 75% smaller than the minimum radial cross-sectional dimension of the first shape.

[0292] 15. The filter element of any of the preceding items, wherein the second end cap is deformable in radial direction by a radial force component of less than 40N.

[0293] 16. A filter element according to any of the preceding items, wherein the second end cap is elastically deformable.

[0294] 17. The filter element of any of items 1 to 15, wherein the second end cap is substantially rigid.

[0295] 18. A filter element according to any of the preceding items, wherein the second end cap comprises a second circumferential seal, preferably the second circumferential seal being integrally formed with the second end cap.

[0296] 19. The filter element of item 18, wherein the second circumferential seal comprises an N-fold rotational symmetry relative to the axis of the filter media pack, for example, the second circumferential seal comprises a 1-fold rotational symmetry relative to the axis of the filter media pack.

[0297] 20. The filter element of clause 18 or 19, wherein the second circumferential seal is arranged along an inclined plane relative to a plane perpendicular to the axis of the filter media pack.

[0298] 21. A filter element according to any one of items 18 to 20, wherein the second open end cover includes a central opening, and wherein the second circumferential seal is implemented as a portion of the second end cover extending radially inward into the central opening, the portion extending radially inward includes at least one axially extending circumferential groove, groove or recess, for example V-shaped or U-shaped, arranged adjacent to the central opening, the groove, groove or recess protruding into the internal volume portion of the filter media pack, preferably, the groove, groove or recess protruding into the internal volume portion of the filter media pack in a direction parallel to the axis of the filter media pack.

[0299] 22. The filter element of any of the preceding items, wherein the filter media pack comprises pleated media, and wherein the media comprises one or more layers selected from a media layer and a support layer.

[0300] 23. The filter element of any of the preceding items, wherein the filter element comprises a self-supporting filter media pack.

[0301] 24. A package comprising a box, a bag, or a sleeve, comprising a filter element according to any of the preceding items, wherein the filter element is held in an elastically deformed configuration by an inner side wall of the box, bag or sleeve.

[0302] 25. A filter assembly, comprising a filter housing having a housing axis and a filter element according to any one of items 1 to 23 above, the filter housing comprising a filter insertion opening (or maintenance opening), wherein the filter insertion opening is too small for the first end cap to be inserted into the filter housing in the first shape of the first end cap; and the filter insertion opening is large enough for the first end cap to be inserted into the filter housing in the second shape of the first end cap.

[0303] 26. A filter assembly according to item 25, wherein the insertion opening includes at least one undercut portion, and wherein a projection of the filter element along the axis of the housing intersects with a projection of the undercut portion along the axis of the housing, and the intersection corresponds to an overlapping area of ​​the projections.

[0304] 27. A filter assembly according to item 26, wherein the projected overlapping area is more than 1% of the projected area of ​​the filter element along the axis of the shell; or, the projected overlapping area is more than 2% of the projected area of ​​the filter element along the axis of the shell; or, the projected overlapping area is more than 3% of the projected area of ​​the filter element along the axis of the shell; or, the projected overlapping area is more than 5% of the projected area of ​​the filter element along the axis of the shell; or, the projected overlapping area is more than 10% of the projected area of ​​the filter element along the axis of the shell.

[0305] 28. The filter assembly according to any one of items 25 to 27, wherein the housing comprises a housing cover for covering the insertion opening, and wherein the housing cover is shaped to be substantially complementary or complementary to the at least one undercut portion.

[0306] 29. A filter assembly housing according to any one of items 25 to 28, wherein the filter assembly further comprises a housing cover for covering the insertion opening, wherein the housing cover and the filter housing are adapted so that the housing cover and the filter housing are connected along an inclined plane, the inclined plane being such that the housing length at the side corresponding to the overlapping area of ​​the projection is longer than the housing length at the opposite side of the housing.

[0307] 30. A filter assembly housing according to item 25 or 29, wherein the filter assembly further comprises a housing cover, wherein the housing cover comprises an internal support structure for the filter media pack, wherein the internal support structure for the filter media pack is, for example, a tower-shaped structure, wherein the internal support structure for the filter media pack preferably has a conical shape, and wherein the internal support structure for the filter media pack protrudes from the inner surface starting from the proximal end portion at the cover portion toward the distal end portion.

[0308] 31. The filter assembly of item 25 or 30, comprising a housing cover, wherein the housing cover includes a pressure sensor mount and optionally a pressure sensor.

[0309] 32. A filter assembly according to any one of items 25 to 31, wherein the filter assembly includes a housing cover, wherein the housing cover includes a sealing surface, which is used to receive the first circumferential seal portion in a sealing manner when the cover is mounted on the filter housing.

[0310] 33. A filter assembly according to any one of items 25 to 32, wherein the filter housing includes a housing cover, and the filter housing includes a first end and a second end, the first end including a filter insertion opening and being configured to receive the cover, the second end being arranged at an end opposite to the first end and including an outlet opening, the second end also including a sealing surface complementary to the second circumferential seal portion for receiving the second circumferential seal portion in a sealed manner.

[0311] 34. A filter assembly according to any one of items 25 to 33, wherein the filter element is a filter element according to item 21, and wherein the cover is a cover according to item 30, wherein the distal end of the support structure is arranged and adapted to be received by a circumferential, for example V-shaped or U-shaped groove, groove or recess extending axially in the circumference of the second circumferential seal of the filter element, and wherein the distal end of the support structure is arranged and adapted to provide a radially outward back pressure to the circumferential seal toward the sealing surface of the filter housing when the cover is mounted on the housing.

[0312] 35. A filter assembly according to any one of items 25 to 34, wherein the shell further comprises at least one partial volume portion for receiving a portion of the first end cap within the shell, the partial volume portion being arranged within the shell below the undercut portion, preferably, the partial volume portion being arranged within the shell just below or near the undercut portion, preferably, the partial volume portion being adjacent to the insertion opening.

[0313] 36. The filter assembly of any one of items 25 to 35, wherein the filter media pack of the filter element is mounted in a twisted configuration.

[0314] 37. The filter assembly of any one of items 25 to 36, wherein the housing includes a housing sidewall disposed generally along an outer radial surface of the filter media pack, the housing sidewall being open and including a lattice structure.

[0315] 38. The filter assembly of any one of items 25 to 37, wherein the radial sidewall of the cover is open and comprises a lattice structure.

[0316] 39. The filter assembly of any one of items 37 or 38, wherein at least one of the lattice structures comprises one or more flow guiding devices.

[0317] 40. A filter housing, comprising: an inlet and an outlet, the housing being adapted to receive a replaceable filter element in a sealed manner so that air flowing from the inlet of the housing to the outlet of the housing is filtered by the filter element, the housing comprising a maintenance opening for receiving the filter element in a main part of the housing, and the housing comprising a housing cover for closing the maintenance opening, wherein the inlet of the housing is arranged in the main part and / or the housing cover, and wherein the inlet comprises a grid-like inlet structure.

[0318] 41. A filter housing according to item 40, wherein the housing includes a housing side wall, which is arranged generally along the outer radial surface of the filter media when the filter media pack is installed in the housing, and the outer radial surface includes a grid structure.

[0319] 42. The filter housing according to item 40 or 41, wherein the radial side wall of the cover comprises a lattice structure.

[0320] 43. A filter housing according to any one of items 40 to 42, wherein at least one of the lattice structure of the cover or the lattice structure of the housing side wall comprises one or more flow guiding devices, such as flow guiding ribs, fins or blades.

[0321] 44. The filter housing according to any of items 40 to 43, wherein the main part of the housing and / or the housing cover comprises plastic.

[0322] 45. The filter housing according to any one of items 40 to 44, wherein the main part of the housing and / or the housing is formed by injection molding.

[0323] For example, the following may be required:

[0324] 1. A filter element according to claim 1, wherein the filter element comprises: a flexible filter media pack, the filter media pack being arranged in a tubular manner about an axis; a first open end cap, the first open end cap being connected to a first axial end of the filter media pack in a fluid-tight manner; and a second open end cap, the second open end cap being connected to a second axial end of the filter media pack in a fluid-tight manner, wherein the second open end cap includes a central opening and a second circumferential seal portion, the second circumferential seal portion including a portion of the second end cap extending radially inwardly into the central opening, the radially inwardly extending portion including at least one circumferential groove, groove or recess arranged adjacent to the central opening, the groove, groove or recess protruding into an interior volume portion of the filter media pack.

[0325] 2. The filter element of item 1, wherein the circumferential grooves, channels or recesses are oriented parallel to the axis of the filter media pack.

[0326] 3. The filter element according to any of the preceding items, wherein the circumferential grooves, channels or recesses comprise bevelled or chamfered portions.

[0327] 4. A filter element according to any one of the preceding items, wherein the groove, groove or recess comprises a radial inner wall and a radial outer wall connected by a bottom wall, and wherein the second circumferential seal portion further comprises a plurality of spacer ribs, the spacer ribs bridging the radial inner wall and the radial outer wall, preferably the spacer ribs being regularly spaced apart.

[0328] 5. The filter element according to item 4, wherein recesses are formed in the grooves and between adjacent spacer ribs.

[0329] 6. A filter element according to any of the preceding items, wherein the groove, channel or recess comprises a radially inner wall and a radially outer wall connected by a bottom wall, and wherein the radially outer wall or the radially inner wall is provided with one, two or more fluid communication channels extending axially.

[0330] 7. A filter element according to any of the preceding items, wherein the filter media pack is of a conical type, i.e., the filter media pack is arranged in a conical manner, wherein the cross-section of the respective conical piece decreases from the first axial end of the media pack to the second axial end of the media pack, and wherein the second end cover has an outer diameter that is smaller than the first end cover.

[0331] 8. The filter element of any of the preceding items, wherein the second end cap is flexible and can be deformed non-destructively, for example between a first shape and a different second shape.

[0332] 9. The filter element of item 8, wherein the minimum radial cross-sectional dimension of the second shape of the second open end cap is at least 5% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cap is at least 10% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cap is at least 15% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cap is at least 20% smaller than the minimum radial cross-sectional dimension of the first shape; or, the second shape of the second open end cap is at least 10% smaller than the minimum radial cross-sectional dimension of the first shape; The minimum radial cross-sectional dimension of the second shape of the second open end cover is at least 25% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cover is at least 30% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cover is at least 40% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cover is at least 50% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cover is at least 75% smaller than the minimum radial cross-sectional dimension of the first shape.

[0333] 10. The filter element of any of the preceding items, wherein the second end cap is deformable in radial direction by a radial force component of less than 30N.

[0334] 11. A filter element according to any of the preceding items, wherein the second end cap is elastically deformable.

[0335] 12. The filter element of any of clauses 1 to 7, wherein the second end cap is substantially rigid.

[0336] 13. A filter element according to any of the preceding items, wherein the second circumferential seal is formed integrally with the second end cap.

[0337] 14. A filter element according to any of the preceding items, wherein the second circumferential seal portion comprises an N-fold rotational symmetry relative to the axis of the filter media pack, for example, the second circumferential seal portion comprises a 1-fold rotational symmetry relative to the axis of the filter media pack.

[0338] 15. The filter element according to item 14, wherein the second circumferential seal portion comprises at least one radially protruding projection.

[0339] 16. The filter element according to item 14, wherein the second circumferential seal portion comprises at least one axially protruding projection.

[0340] 17. A filter element according to any of the preceding items, wherein the second circumferential seal portion is arranged along an inclined plane relative to a plane perpendicular to the axis of the filter media pack.

[0341] 18. The filter element of any of the preceding items, wherein the filter media pack comprises pleated media, and wherein the media comprises one or more layers selected from a media layer and a support layer.

[0342] 19. The filter element according to any of the preceding items, wherein the second end cap is connected to the filter medium by potting, and wherein the second end cap is manufacturable by potting.

[0343] 20. A filter assembly, comprising a filter housing having a housing axis and a filter element according to any one of items 1 to 19 arranged in the housing along the housing axis, the filter housing comprising a housing cover, the housing cover comprising an internal support structure of a filter media pack, the internal support structure of the filter media pack being, for example, a tower-like structure, the internal support structure of the filter media pack preferably having a conical shape, the internal support structure of the filter media pack protruding from an inner surface starting from the proximal end at the cover toward the distal end, wherein the filter housing comprises a first end and a second end, the first end comprising a filter insertion opening and being configured to receive the cover, the second end being arranged at an end opposite to the first end and comprising an outlet opening, the second end also comprising a sealing surface complementary to the second circumferential seal portion for receiving the second circumferential seal portion in a sealed manner.

[0344] 21. A filter assembly according to item 20, wherein the distal end of the support structure is arranged and adapted to be received by an axially extending circumferential groove, groove or recess of the second circumferential seal portion of the filter element, and the distal end of the support structure is arranged and adapted to provide a radially outward back pressure to the circumferential seal portion toward the sealing surface of the filter housing when the cover is mounted on the housing.

[0345] 22. A filter assembly according to any one of items 20 to 21 with respect to item 15, wherein the distal end of the support structure includes at least one radially protruding protrusion as follows: at least one protrusion of the distal end of the support structure corresponds to at least one radially protruding protrusion of the second circumferential sealing portion.

[0346] 23. A filter assembly according to any one of items 20 to 22 with respect to item 16, wherein the distal end portion of the support structure includes at least one axially protruding protrusion: the at least one protrusion of the distal end portion of the support structure corresponds to at least one axially protruding protrusion of the second circumferential sealing portion.

[0347] For example, the following may also be required:

[0348] 1. A filter element, the filter element comprising: a preferably flexible filter media pack, the filter media pack being arranged in a tubular manner around an axis; a first open end cap, the first open end cap being connected to a first axial end of the filter media pack in a fluid-tight manner; and a second open end cap, the second open end cap being connected to a second axial end of the filter media pack in a fluid-tight manner, wherein the second open end cap includes a second circumferential seal portion, the second circumferential seal portion extending radially outward from the media pack, the second circumferential seal portion including or forming a circumferential groove, recess or recess, the circumferential groove, recess or recess protruding in a direction toward the first end cap, preferably, the circumferential groove, recess or recess protruding in a direction parallel to an outer wall of the filter media pack.

[0349] 2. The filter element of item 1, wherein the circumferential grooves, channels or recesses are oriented in a direction parallel to the axis of the filter media pack.

[0350] 3. The filter element according to any of the preceding items, wherein the circumferential groove, channel or recess comprises a bevelled or chamfered portion.

[0351] 4. A filter element according to any one of the preceding items, wherein the groove, groove or recess comprises a radial inner wall and a radial outer wall connected by a bottom wall, and wherein the second circumferential seal portion further comprises a plurality of spacer ribs, the spacer ribs bridging the radial inner wall and the radial outer wall, preferably the spacer ribs being regularly spaced apart.

[0352] 5. The filter element according to item 4, wherein recesses are formed in the grooves and between adjacent spacer ribs.

[0353] 6. A filter element according to any of the preceding items, wherein the groove, channel or recess comprises a radially inner wall and a radially outer wall connected by a bottom wall, and wherein the radially outer wall or the radially inner wall is provided with one, two or more fluid communication channels extending axially.

[0354] For example, the following may also be required:

[0355] 1. A housing cover for a filter housing, the housing cover comprising an axial end wall connected to a circumferential side wall arranged around a longitudinal axis, wherein a projection of the axial end wall along the longitudinal axis onto a plane perpendicular to the longitudinal axis comprises a one-fold rotational symmetry around the longitudinal axis.

[0356] 2. A shell cover according to item 1, wherein the shell cover includes an axial end wall connected to a circumferential side wall arranged around a longitudinal axis, and the cover is defined by a lower edge of a side wall around a shell joining opening, wherein the circumferential side wall is interrupted (or includes one or more gaps, such as annular gaps) within one or more angular ranges around the longitudinal axis, or the circumferential side wall is straight or approximately straight.

[0357] 3. A shell cover according to item 1 or 2, wherein the contour of the axial end wall corresponds roughly to one or more successive portions of a predetermined annular shape, the one or more successive portions being connected between adjacent annular portions via one or more chords of the annular shape, and wherein the circumferential side wall is interrupted or straight in the area corresponding to the chords.

[0358] 4. The housing cover according to any of the preceding items, further comprising a sensor port opening in the axial end wall.

[0359] 5. The housing cover according to any of the preceding items, comprising an inner surface and a circumferential sealing surface portion arranged on the inner surface for receiving a filter element seal.

[0360] 6. The housing cover according to item 5, wherein the circumferential sealing surface portion protrudes axially from the axial end wall on the inner surface.

[0361] 7. The housing cover according to any one of items 5 or 6, wherein the circumferential sealing surface portion comprises N-fold rotational symmetry.

[0362] 8. The housing cover according to any of the preceding items, further comprising one or more axial end wall openings in the axial end wall.

[0363] 9. The housing cover according to item 8, comprising one or more centrally located axial end wall outlet openings positioned radially within the circumferential sealing surface portion.

[0364] 10. The housing cover according to any one of the preceding items comprises: a second circumferential sealing surface portion, which is arranged on the inner surface for accommodating a second filter element sealing portion, and the second circumferential sealing surface portion is radially arranged within the first circumferential sealing surface portion; and one or more centrally positioned axial end wall inlet openings, which are radially arranged within the second circumferential sealing surface portion.

[0365] 11. The housing cover according to item 10, wherein the second circumferential sealing surface portion comprises N-fold rotational symmetry.

[0366] 12. The housing cover according to any of the preceding items, further comprising a (inner or outer) filter medium support structure protruding axially or predominantly axially from an inner surface starting from the axial end wall.

[0367] 13. The shell cover according to item 12, wherein the medium support structure comprises a tower-like structure, preferably, the tower-like structure is a conical tower-like structure, and the tower-like structure extends axially from a proximal end at the inner surface of the cover away from the cover to a distal end.

[0368] 14. The housing cover according to item 13, wherein the distal end of the tower-like structure comprises an N-fold rotational symmetry about the longitudinal axis.

[0369] 15. The housing cover according to any of the preceding items, wherein the lower edge is defined by a plane that is inclined relative to a direction perpendicular to the longitudinal axis.

[0370] 16. A shell cover according to item 15, wherein the axial end wall is arranged in a manner perpendicular to the longitudinal axis, and the circumferential side wall extends between a minimum width and a maximum width, the minimum width is located at the minimum axial distance between the lower edge and the axial end wall, and the maximum width is located at the maximum axial distance between the lower edge and the axial end wall.

[0371] 17. The housing cover according to any of the preceding items, wherein the housing side wall comprises one or more housing cover side wall openings.

[0372] 18. The shell cover according to any one of items 2 to 17 above, further comprising at least a sub-component of a cover closing device or arrangement, wherein the sub-component is arranged at or adjacent to a position where the circumferential side wall is interrupted (or includes one or more gaps), or the circumferential side wall is straight or substantially straight.

[0373] 19. An assembly comprising a main housing and a housing cover according to any one of the preceding items, the main housing having a maintenance opening for receiving a filter element in the housing, the housing cover covering the maintenance opening, wherein the maintenance opening comprises at least one undercut portion which is complementary to an interrupted portion or a straight portion of the housing cover when the cover is arranged on the main housing.

[0374] For example, the following may also be required:

[0375] 1. A housing cover for a filter housing, the housing cover comprising an axial end wall connected to a circumferential side wall arranged about a longitudinal axis, the housing cover defining a lower edge of the side wall, the lower edge surrounding a filter housing engagement opening, wherein the lower edge is defined by a plane inclined relative to a direction perpendicular to the longitudinal axis.

[0376] 2. A shell cover according to item 1, wherein the axial end wall is arranged perpendicular to the longitudinal axis, and the circumferential side wall extends between a minimum width and a maximum width, the minimum width is located at the minimum axial distance between the lower edge and the axial end wall, and the maximum circumferential width is located at the maximum axial distance between the lower edge and the axial end wall.

[0377] 3. The housing cover according to any of the preceding items, wherein the housing side wall comprises one or more housing side wall openings.

[0378] 4. The housing cover according to any of the preceding items, further comprising a sensor port opening in the axial end wall.

[0379] 5. The housing cover according to items 1 to 3, comprising an inner surface and a circumferential sealing surface portion arranged on the inner surface for receiving a filter element seal.

[0380] 6. The housing cover according to item 5, wherein the circumferential sealing surface portion protrudes axially from the axial end wall on the inner surface.

[0381] 7. The housing cover according to any one of items 5 or 6, wherein the circumferential sealing surface portion comprises N-fold rotational symmetry.

[0382] 8. The housing cover according to any of the preceding items, further comprising one or more axial end wall openings in the axial end wall.

[0383] 9. The housing cover according to item 8, comprising one or more centrally located axial end wall outlet openings positioned radially within the circumferential sealing surface portion.

[0384] 10. A housing cover according to any one of items 1 to 8, wherein the housing cover comprises: a second circumferential sealing surface portion, which is arranged on the inner surface for accommodating a second filter element sealing portion, and the second circumferential sealing surface portion is radially arranged within the first circumferential sealing surface portion; and one or more centrally positioned axial end wall inlet openings, which are radially arranged within the second circumferential sealing surface portion.

[0385] 11. The housing cover according to item 10, wherein the second circumferential sealing surface portion comprises N-fold rotational symmetry.

[0386] 12. The housing cover according to any of the preceding items, further comprising a (internal or external) filter media support structure protruding axially from an inner surface from the axial end wall.

[0387] 13. The shell cover according to item 12, wherein the medium support structure comprises a tower structure, preferably, the tower structure is a conical tower structure, and the tower structure extends axially from a proximal end at the inner surface of the cover away from the cover to a distal end.

[0388] 14. The housing cover according to item 13, wherein the distal end of the tower-like structure comprises an N-fold rotational symmetry about the longitudinal axis.

[0389] 15. A shell cover according to any of the preceding items, wherein the circumferential side wall is interrupted (or includes one or more annular gaps) within one or more angular ranges around the longitudinal axis, or the circumferential side wall is straight.

[0390] 16. A shell cover according to item 15, wherein the contour of the axial end wall corresponds roughly to one or more successive portions of a predetermined annular shape portion, one or more successive portions being connected between adjacent annular portions via one or more chords of the annular shape portion, and wherein the circumferential side wall is interrupted or straight in the area corresponding to the chords (thereby defining one or more flat portions of the shell cover).

[0391] 17. An assembly comprising a main housing and a housing cover according to any one of the preceding items, the main housing having a maintenance opening for receiving a filter element therein, the housing cover being used to cover the maintenance opening, wherein the maintenance opening comprises an edge located in a plane inclined relative to a direction perpendicular to the longitudinal axis of the housing cover, the plane corresponding to the inclined plane of the lower edge of the housing cover.

[0392] Reference numerals

[0393]

[0394]

[0395]

[0396]

Claims

1. A filter element, comprising: a flexible filter media pack arranged in a tubular manner about an axis; a first open end cap connected in a fluid-tight manner to a first axial end of the filter media pack; as well as A second open end cap is fluid-tightly connected to a second axial end of the filter media pack, wherein the first end cap is flexible and non-destructively deformable between a first shape and a second, different shape.

2. The filter element according to claim 1, wherein The minimum radial cross-sectional dimension of the second shape of the first open end cap is at least 5% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the first open end cap is at least 10% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the first open end cap is at least 15% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the first open end cap is at least 20% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the first open end cap is at least 25% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the first open end cap is at least 30% smaller than the minimum radial cross-sectional dimension of the first shape; or, The minimum radial cross-sectional dimension of the second shape of the first open end cover is at least 40% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the first open end cover is at least 50% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the first open end cover is at least 75% smaller than the minimum radial cross-sectional dimension of the first shape.

3. The filter element according to claim 1 or 2, wherein The first end cover is elastically deformable.

4. The filter element according to any one of the preceding claims, wherein The first end cap is connected to the filter media pack and can be manufactured by potting.

5. The filter element according to any one of the preceding claims, wherein The first end cover comprises a first circumferential sealing portion. Preferably, the first circumferential sealing portion is integrally formed with the first end cover.

6. The filter element according to claim 5, wherein The first circumferential seal portion includes N-fold (or 1-fold) rotational symmetry with respect to an axis of the filter media pack.

7. The filter element according to claim 5 or 6, wherein The first circumferential seal is arranged along an inclined plane relative to a plane perpendicular to the axis of the filter media pack.

8. A filter element according to any one of the preceding claims, wherein The first end cap is deformable in a radial direction by a radial force component less than 40N.

9. A filter element according to any one of the preceding claims, wherein The first end cap further comprises at least one manipulation means, such as a handle, adapted and arranged to pull a portion of the first end cap radially inwardly.

10. The filter element of claim 9, wherein The steering means includes a handle bar or structure bridging opposite sides of an open end cap over a central opening in the first end cap.

11. The filter element according to any one of claims 9 or 10, wherein The maneuvering device comprises at least one baffle or ear-like structure pointing radially inwardly or radially outwardly.

12. A filter element according to any one of the preceding claims, wherein The filter media pack is of a conical type (or arranged in a conical manner), wherein the cross-section of the respective cone decreases from the first axial end of the media pack to the second axial end of the media pack, and wherein the second end cap has a smaller outer diameter than the first end cap.

13. A filter element according to any one of the preceding claims, wherein The second end cap is flexible and the second end cap is capable of non-destructively deforming between a first shape and a second, different shape.

14. A filter element according to any one of the preceding claims, wherein The minimum radial cross-sectional dimension of the second shape of the second open end cover is at least 5% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cover is at least 10% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cover is at least 15% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cover is at least 20% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cover is at least 25% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cover is at least 30% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cover is at least 40% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cover is at least 50% smaller than the minimum radial cross-sectional dimension of the first shape; or, the minimum radial cross-sectional dimension of the second shape of the second open end cover is at least 75% smaller than the minimum radial cross-sectional dimension of the first shape.

15. A filter element according to any one of the preceding claims, wherein The second end cover can be deformed in the radial direction by a radial force component less than 40N.

16. A filter element according to any one of the preceding claims, wherein The second end cover is elastically deformable.

17. A filter element according to any one of claims 1 to 15, wherein The second end cap is substantially rigid.

18. A filter element according to any one of the preceding claims, wherein The second end cover comprises a second circumferential sealing portion. Preferably, the second circumferential sealing portion is integrally formed with the second end cover.

19. The filter element of claim 18, wherein The second circumferential seal portion includes N-fold (or 1-fold) rotational symmetry with respect to an axis of the filter media pack.

20. A filter element according to claim 18 or 19, wherein The second circumferential seal portion is arranged along an inclined plane relative to a plane perpendicular to the axis of the filter media pack.

21. A filter element according to any one of claims 18 to 20, wherein The second opening end cap includes a central opening, and wherein the second circumferential seal is implemented as a portion of the second end cap extending radially inwardly into the central opening, the portion extending radially inwardly including at least one axially extending circumferentially V-shaped or U-shaped groove, groove or recess arranged adjacent to the central opening, the groove, groove or recess protruding into the inner volume portion of the filter media pack, preferably, the groove, groove or recess protruding into the inner volume portion of the filter media pack in a direction parallel to the axis of the filter media pack.

22. A filter element according to any one of the preceding claims, wherein The filter media pack comprises pleated media, and wherein the pleated media comprises one or more layers selected from a media layer and a support layer.

23. A filter element according to any one of the preceding claims, wherein The filter element includes a self-supporting filter media pack.

24. A package, comprising a box, bag or sleeve, comprising a filter element according to any one of the preceding claims, wherein The filter element is held in the resiliently deformed configuration by the inner side walls of the box, bag or sleeve.

25. A filter assembly comprising a filter housing having a housing axis and a filter element according to any one of the preceding claims 1 to 23, the filter housing comprising a filter insertion opening (or service opening), wherein the filter insertion opening is too small for the first end cap to be inserted into the filter housing in the first shape of the first end cap; And, the filter insertion opening is large enough for the first end cap to be inserted into the filter housing in the second shape of the first end cap.

26. The filter assembly of claim 25, wherein The insertion opening comprises at least one undercut portion, and wherein a projection of the filter element along the housing axis intersects a projection of the undercut portion along the housing axis, the intersection corresponding to an overlapping area of ​​the projections.

27. The filter assembly of claim 26, wherein The overlapping area of ​​the projections is more than 1% of the projection area of ​​the filter element along the axis of the shell; or, the overlapping area of ​​the projections is more than 2% of the projection area of ​​the filter element along the axis of the shell; or, the overlapping area of ​​the projections is more than 3% of the projection area of ​​the filter element along the axis of the shell; or, the overlapping area of ​​the projections is more than 5% of the projection area of ​​the filter element along the axis of the shell; or, the overlapping area of ​​the projections is more than 10% of the projection area of ​​the filter element along the axis of the shell.

28. A filter assembly according to any one of claims 25 to 27, wherein The housing comprises a housing cover for covering the insertion opening, and wherein the housing cover is shaped to be substantially complementary or complementary to at least one of the undercut portions.

29. The filter assembly housing according to any one of claims 25 to 28, further comprising a housing cover for covering the insertion opening, wherein: The housing cover and the filter housing are adapted so that they meet along an inclined plane which causes the housing length at a side of the housing corresponding to the projected overlap region to be longer than at an opposite side of the housing.

30. A filter assembly housing according to claim 25 or 29, wherein the filter assembly further comprises a housing cover, wherein the housing cover comprises an internal support structure of a filter media pack, wherein the internal support structure of the filter media pack is, for example, a tower-shaped structure, and preferably, the internal support structure of the filter media pack has a conical shape, and the internal support structure of the filter media pack protrudes from the inner surface starting from the proximal end portion of the cover toward the distal end portion.

31. A filter assembly according to claim 25 or 30, comprising a housing cover, wherein: The housing cover includes a pressure sensor mount and an optional pressure sensor.

32. A filter assembly according to any one of claims 25 to 31 comprising a housing cover, wherein The housing cover comprises a sealing surface for receiving the first circumferential seal in a sealing manner when the cover is mounted on the filter housing.

33. A filter assembly according to any one of claims 25 to 32, wherein The filter housing includes a housing cover, and the filter housing includes a first end and a second end, the first end including a filter insertion opening and being adapted to receive the cover, the second end being arranged at an end opposite to the first end and including an outlet opening, the second end also including a sealing surface complementary to the second circumferential seal for receiving the second circumferential seal in a sealing manner.

34. A filter assembly according to any one of claims 25 to 33, wherein The filter element is a filter element according to claim 21, and wherein the cover is a cover according to claim 30, wherein the distal end of the support structure is arranged and adapted to be received by a V-shaped or U-shaped groove, groove or recess in the axially extending circumferential direction of the second circumferential seal of the filter element, and the distal end of the support structure is arranged and adapted to provide a radially outward back pressure to the circumferential seal toward the sealing surface of the filter housing when the cover is mounted on the housing.

35. A filter assembly according to any one of claims 25 to 34, wherein The housing further comprises at least one partial volume portion for receiving a portion of the first end cap in the housing, the partial volume portion being arranged in the housing below the undercut portion, preferably, the partial volume portion being arranged in the housing just below or adjacent to the undercut portion, preferably, the partial volume portion being adjacent to the insertion opening.

36. A filter assembly according to any one of claims 25 to 35, wherein The filter media pack of the filter element is installed in a twisted configuration.

37. A filter assembly according to any one of claims 25 to 36, wherein The housing includes a housing sidewall disposed generally along an outer radial surface of the filter media pack, the housing sidewall being open and including a lattice structure.

38. A filter assembly according to any one of claims 25 to 37, wherein The radial sidewall of the cover is open and comprises a lattice structure.

39. A filter assembly according to any one of claims 37 or 38, wherein At least one of the lattice structures comprises one or more flow directing means.

40. A filter housing, comprising: an inlet and an outlet of the housing, the housing being adapted to receive a replaceable filter element in a sealed manner so that air flowing from the inlet of the housing to the outlet of the housing is filtered by the filter element, the housing comprising a service opening for receiving the filter element in a main portion of the housing, and the housing comprising a housing cover for closing the service opening, Wherein, the inlet of the housing is provided in the main portion and / or the housing cover, and wherein the inlet comprises a grid-like inlet structure.

41. The filter housing of claim 40, wherein The housing comprises a housing sidewall arranged generally along an outer radial surface of the filter element when the filter element is mounted in the housing, and the outer radial surface comprises a lattice structure.

42. A filter housing according to claim 40 or 41, wherein The radial side wall of the cover comprises a lattice structure.

43. A filter housing according to any one of claims 40 to 42, wherein At least one of the lattice structure of the cover or the lattice structure of the housing side wall comprises one or more flow guiding means, such as flow guiding ribs, fins or blades.

44. A filter housing according to any one of claims 40 to 43, wherein The main part of the housing and / or the housing cover comprises plastic.

45. A filter housing according to any one of claims 40 to 44, wherein The main part of the housing and / or the housing is formed by injection molding.

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