Safety Filter Element

Abstract

The present disclosure relates to a safety filter element for backing up a failure of a main filter element with a primary filter media pack. The safety filter element comprises a secondary filter media pack and a shell, an inner first part of the peripheral wall of the shell surrounding the peripheral side of the secondary filter media pack, and an inner second part of the peripheral wall of the shell defining a radial boundary of a cavity arranged between a first opening of the shell and a fluid inlet side of the secondary filter media pack. The cavity allows to receive or at least partially receive the primary filter media pack of the main filter element. The safety filter element comprises a first seal member comprising a first peripheral sealing part for sealing to the shell and a second peripheral sealing part for sealing to the main filter element. The second peripheral sealing part has a single-fold rotationally symmetric outer shape.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application was filed on September 16, 2022, and claims the benefit of and priority to U.S. Provisional Patent Application No. 63 / 245,612, filed on September 17, 2021, the disclosure of which is incorporated by reference in its entirety into this application.

[0002] The present disclosure relates generally to filter elements and filter assemblies. More precisely, the present disclosure relates to a safety filter element for backing up a failure of a main filter element that comprises a primary filter media pack. [Background technology]

[0003] Filter elements, also called filter cartridges, for filtering fluids are used in a wide variety of filtering applications. The fluids can be liquids or gases, including, for example, air.

[0004] The filter element is typically an element that must be removed from the housing of the filter system and replaced at regular intervals, or when the filtration performance falls below a critical threshold level.

[0005] The filter element includes a media pack containing a filter media for removing contaminants as the fluid flows through the filter media. Commonly used and commercially available filter media are, for example, pleated media or fluted media. Fluted media is also called Z-media.

[0006] More advanced filter assemblies, for example air filter assemblies for vehicles, comprise two filter elements: a primary filter element, also called the main filter element, and a secondary filter element, also called the safety filter element.

[0007] The safety filter element backs up the main filter element, thereby protecting the vehicle's engine, for example, while the primary filter is removed from the housing during service.

[0008] The safety filter element also protects the engine against hidden damage to the primary filter element, e.g., damage from cleaning, or against failure of the primary filter element, e.g., due to incorrect installation or due to installation of an incorrectly sized primary filter element.

[0009] Generally, safety filter elements are more open, less restrictive, and less effective than primary filter elements, and therefore do not generally improve the overall operating efficiency of the filter system.

[0010] The life of the safety seal element is also generally significantly longer than the life of the main filter element, eg, 2 to 4 times longer, and therefore the replacement intervals for the primary and secondary filter elements are different.

[0011] Typically, as disclosed, for example, in U.S. Patent Application Publication No. 2018 / 0369735 A1, the safety filter element and the main filter element each include a seal member for sealing against an inner wall of the housing of the filter system, and the seal members are replaced according to a maintenance procedure that takes into account the seal member specifications for life span. Typically, the seal member of the main filter element is replaced as part of the replacement of the entire filter element.

[0012] On the one hand, there is a need in the industry to maximize the use of certain filter components and replace them only when completely necessary. On the other hand, there is also a need to ensure that the various components of the filter assembly are correctly installed and secured within the housing of the filter system. Furthermore, there is a need to provide filter elements and components that can be assembled in a simple and quick manner, thereby facilitating maintenance operations.

[0013] Thus, there is room for an improved safety filter element and filter assembly including a safety filter element and a main filter element that facilitates maintenance procedures and ensures safe and correct installation. Summary of the Invention [Problem to be solved by the invention]

[0014] SUMMARY OF THE DISCLOSURE It is an object of the present disclosure to provide a safety filter element for filtering fluids that makes maintenance easy and reliable. [Means for solving the problem]

[0015] The present disclosure is defined in the accompanying independent claims. The dependent claims define advantageous embodiments.

[0016] According to a first aspect of the present disclosure, a safety filter element is provided for backing up a main filter element with a primary filter media pack in the event of failure. In an embodiment, the main filter element is, for example, a main filter element for air purification.

[0017] The safety filter element comprises a secondary media pack having a peripheral side extending longitudinally from a fluid inlet side to a fluid outlet side, and a shell with a peripheral wall extending longitudinally from a first opening at a first end of the shell to a second opening at a second end of the shell, an inner first portion of the peripheral wall of the shell surrounding the peripheral side of the secondary media pack, and an inner second portion of the peripheral wall of the shell defining a radial boundary of a cavity disposed between the first opening of the shell and the fluid inlet side of the secondary media pack for receiving or at least partially receiving a primary media pack of the main filter element.

[0018] The safety filter element further comprises a first seal member having a first peripheral sealing portion for sealing to the shell and a second peripheral sealing portion for sealing to the main filter element when the primary filter media pack of the main filter element is received in the cavity, the second peripheral sealing portion of the first seal member having a single-fold rotationally symmetric outer shape.

[0019] By providing a safety filter element having a shell that forms a cavity for receiving a main filter media pack, a service tool is provided that forms a useful interface between the housing of the filter system and the main filter element. In fact, since the frequency for replacing the secondary filter media pack is much less than the frequency for replacing the primary filter media pack, the safety filter element can remain locked into the filter system during replacement of the main filter element.

[0020] By providing a first seal member with a second peripheral sealing portion having a contoured shape with single-fold rotational symmetry, the main filter element can only be coupled in one direction to the safety filter element such that the second peripheral sealing portion of the first seal member sealingly cooperates with a sealing surface of the main filter element. This reduces the risk of incorrectly installing the main filter element and facilitates maintenance procedures, as there is only one sure direction for coupling the main filter element to the safety filter element.

[0021] As a result of the unique features of the safety filter element according to the present disclosure, the main filter element is also simplified since it requires fewer components, thereby reducing the cost, facilities, and manufacturing procedures of the main filter element. Indeed, with the safety filter element according to the present disclosure, the main filter element does not require a sealing member, nor does it require a protecting shell, since the shell of the safety filter element is used to protect the primary filter media pack.

[0022] In an embodiment, the first seal member is permanently bonded to the shell by sealingly attaching the first peripheral sealing portion to the shell, for example by using an adhesive, or alternatively by overmolding the first seal member onto the shell via multi-component injection molding.

[0023] In other embodiments, the first seal member is removably coupled to the shell such that the first seal member can be replaced without replacing the shell.

[0024] In embodiments where the first seal member for sealing the safety filter element to the main filter element is permanently bonded to the shell of the safety filter, the first seal member remains in place when the main filter element is replaced. In this manner, the first seal member can be used multiple times with different main filter elements. The safety filter element is removed from the filter system only when the first seal member needs replacing, which is less frequently than the replacement of the main filter media pack.

[0025] In an embodiment, the first seal member is a lip-type seal member having at least one sealing lip forming a second peripheral sealing portion of the first seal member for sealing the safety filter element to the main filter element.

[0026] In an embodiment, the safety filter element includes a connection structure for locking the safety filter element to a housing of the filter system. Typically, the connection structure is coupled to the shell.

[0027] Advantageously, by providing a connection structure for locking the safety filter element to the housing of the filter system, the safety filter element is locked to the housing of the filter system independent of locking a cover or precleaner to the housing of the filter system, such that when the main filter element is replaced, the safety filter element remains locked within the housing of the filter system.

[0028] In an embodiment, the safety filter element includes a second seal member for sealing the safety filter element to the housing of the filter system. The second seal member may be a permanent seal permanently bonded to the shell, or alternatively, the second seal member may be removably bonded to the shell. Preferably, the second seal member is bonded to an exterior of the peripheral wall of the shell.

[0029] In an embodiment, the second seal member has an inner peripheral side for sealing to the shell and an outer peripheral side for sealing to the housing, the inner peripheral side being bonded to the outside of the peripheral wall of the shell. Preferably, the outer peripheral side of the second seal member has one or more sealing lips.

[0030] According to a second aspect of the present disclosure, there is provided a filter assembly including a safety filter element and a main filter element, the main filter element including a primary media pack receivable in the cavity of the safety filter element, the main filter element further including a peripheral frame sealingly attached to the primary media pack, the peripheral frame including a peripheral sealing surface configured for sealingly cooperating with a second peripheral sealing portion of the first seal member when the primary media pack of the main filter element is received in the cavity.

[0031] In an embodiment, a filter assembly according to the present disclosure is a filter assembly for air purification.

[0032] According to a third aspect of the present disclosure, there is provided a filter system comprising a filter assembly according to the present disclosure and a housing for receiving the filter assembly.

[0033] These and further aspects of the present disclosure will now be described in more detail, by way of example, and with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0034] [Figure 1a] 1A-1D are schematic diagrams showing various views of a first embodiment of a safety filter element according to the present disclosure, in which Fig. 1a is a top view, dashed arrows B, C, D indicate the viewing directions of Figs. 1b, 1c, and 1d, respectively, and Fig. 1e is an enlarged view of a portion of the safety filter indicated in Fig. 1d by dashed arrow E; [Figure 1b]1A-1D are schematic diagrams showing various views of a first embodiment of a safety filter element according to the present disclosure, in which Fig. 1a is a top view, dashed arrows B, C, D indicate the viewing directions of Figs. 1b, 1c, and 1d, respectively, and Fig. 1e is an enlarged view of a portion of the safety filter indicated in Fig. 1d by dashed arrow E; [Figure 1c] 1A-1D are schematic diagrams showing various views of a first embodiment of a safety filter element according to the present disclosure, in which Fig. 1a is a top view, dashed arrows B, C, D indicate the viewing directions of Figs. 1b, 1c, and 1d, respectively, and Fig. 1e is an enlarged view of a portion of the safety filter indicated in Fig. 1d by dashed arrow E; [Figure 1d] 1A-1D are schematic diagrams showing various views of a first embodiment of a safety filter element according to the present disclosure, in which Fig. 1a is a top view, dashed arrows B, C, D indicate the viewing directions of Figs. 1b, 1c, and 1d, respectively, and Fig. 1e is an enlarged view of a portion of the safety filter indicated in Fig. 1d by dashed arrow E; [Figure 1e] 1A-1D are schematic diagrams showing various views of a first embodiment of a safety filter element according to the present disclosure, in which Fig. 1a is a top view, dashed arrows B, C, D indicate the viewing directions of Figs. 1b, 1c, and 1d, respectively, and Fig. 1e is an enlarged view of a portion of the safety filter indicated in Fig. 1d by dashed arrow E; [Figure 2a] FIG. 1 illustrates an isometric view of an embodiment of a filter assembly including a safety filter element and a main filter element. [Figure 2b] FIG. 2b illustrates a side view of the filter assembly shown in FIG. 2a after the primary filter media pack has been received into the cavity of the safety filter element. [Figure 2c] FIG. 2b is an enlarged cross-sectional view of a portion of the filter assembly shown in FIG. 2a. [Figure 3a] 1A and 1B illustrate schematic cross-sections of embodiments of a safety filter element in which a first seal member is coupled to an inner wall of a shell to form a radial seal. [Figure 3b] 1 illustrates a schematic cross-section of an embodiment of a safety filter element in which the shell includes a flange and the first seal member is coupled to the flange to form an axial seal. [Figure 3c] 1A-1C are schematic diagrams illustrating cross-sections of embodiments of safety filter elements in which a first shell portion surrounding a secondary media pack has a different circumference than a second shell portion for receiving a primary media pack. [Figure 3d] 1A-1C are schematic cross-sectional views of an embodiment of a safety filter element in which the shell includes flanges positioned at an oblique angle relative to the longitudinal direction. [Figure 4a] 1A-1C are schematic diagrams illustrating an embodiment of a safety filter element in which the secondary media pack is removable from the shell. [Figure 4b] 1A-1C are schematic diagrams illustrating an embodiment of a safety filter element in which the secondary media pack is removable from the shell. [Figure 5a] 1 shows two embodiments of a first seal member in which the second peripheral sealing portion has a single rotationally symmetric outer shape. [Figure 5b] 1 shows two embodiments of a first seal member in which the second peripheral sealing portion has a single rotationally symmetric outer shape. [Figure 6] 1A-1E show isometric views of example embodiments of a main filter element that can be inserted into the safety filter element shown in FIGS. 1a-1e. [Figure 7] 1 shows a cross-sectional view of a filter system including a housing, a safety filter element, a main filter element, and a precleaner. [Figure 8] 8 illustrates an enlarged cross-sectional view of a portion of the filter system of FIG. 7 showing a first seal member that seals to the main filter element and a second seal member that seals to a wall of the housing.

[0035] 9-37 show preferred embodiments of the air cleaner assembly, safety filter element, main filter element, and housing (including a main housing portion and a precleaner or cover portion) of the present disclosure. [Figure 9] Exploded views of the assembly from four different angles. [Figure 10] Exploded views of the assembly from four different angles. [Figure 11] Exploded views of the assembly from four different angles. [Figure 12] Exploded views of the assembly from four different angles. [Figure 13] 1A-1C are cross-sectional views of a filter assembly along different cutting planes. [Figure 14] 1A-1C are cross-sectional views of a filter assembly along different cutting planes. [Figure 15] 1A-1C are cross-sectional views of a filter assembly along different cutting planes. [Figure 16] 1A-1D are exploded cross-sectional views of a filter assembly along different cutting planes. [Figure 17] 1A-1D are exploded cross-sectional views of a filter assembly along different cutting planes. [Figure 18] 1A-1D are exploded cross-sectional views of a filter assembly along different cutting planes. [Figure 19] 1A-1C are different perspective views of the safety filter element. [Figure 20] 1A-1C are different perspective views of the safety filter element. [Figure 21] 1A-1C are different perspective views of the safety filter element. [Figure 22] 2A-2C are different perspective cross-sectional views of the safety filter element. [Figure 23] 2A-2C are different perspective cross-sectional views of the safety filter element. [Figure 24] 2A-2C are different perspective cross-sectional views of the safety filter element. [Diagram 25] FIG. 2 is a different perspective view of the main filter element. [Figure 26] FIG. 2 is a different perspective view of the main filter element. [Figure 27] FIG. 2 is a cross-sectional perspective view of the main filter element; [Figure 28] FIG. 2 is a cross-sectional perspective view of the main filter element; [Figure 29] FIG. 2 is a cross-sectional perspective view of the main filter element; [Diagram 30]1A-1C are different perspective cross-sectional views of a combined safety filter element and main filter element. [Diagram 31] 1A-1C are different perspective cross-sectional views of a combined safety filter element and main filter element. [Diagram 32] 1A-1C are different perspective cross-sectional views of a combined safety filter element and main filter element. [Diagram 33] 1A-1C are different perspective cross-sectional views of a combined safety element and filter housing (main housing portion). [Diagram 34] 1A-1C are different perspective cross-sectional views of a combined safety element and filter housing (main housing portion). [Diagram 35] FIG. 16 is a perspective cross-sectional view of the filter assembly similar to FIGS. 13-15, but excluding the cover or portion of the precleaner device. [Diagram 36] FIG. 16 is a perspective cross-sectional view of the filter assembly similar to FIGS. 13-15, but excluding the cover or portion of the precleaner device. [Figure 37] FIG. 16 is a perspective cross-sectional view of the filter assembly similar to FIGS. 13-15, but excluding the cover or portion of the precleaner device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] The present disclosure has been described with reference to specific embodiments, which are illustrative of the present disclosure and should not be considered limiting. Those skilled in the art will recognize that the present disclosure is not limited to what has been specifically shown and / or described, and that alternative or modified embodiments may be developed in light of the entire teachings of the present disclosure. The illustrated figures are schematic only and non-limiting.

[0037] The use of the verb "to comprise" and its respective conjugations does not exclude the presence of elements other than those stated. The use of the articles "a", "an" or "the" before an element does not exclude the presence of a plurality of such elements.

[0038] Furthermore, the terms first, second, and the like in the description and claims are used to distinguish between similar elements and are not necessarily used to describe an order, either temporally, spatially, sequentially, or in any other manner. It will be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the disclosure described herein are capable of operating in orders other than those described or illustrated herein.

[0039] Throughout this specification, a reference to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment is included in one or more embodiments of the disclosure. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification do not necessarily all refer to the same embodiment, but may. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments, as would be apparent to one of ordinary skill in the art from this disclosure.

[0040] The words "preferred" and "preferably" refer to embodiments of the invention that may provide certain benefits, under particular circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the invention.

[0041] Single rotational symmetry and mirror symmetry, definition The concept of single-fold rotational symmetry is well known in the art. Throughout this disclosure, when a geometry, such as the geometry of the second peripheral sealing portion of the seal member, is specified as having "single-fold rotational symmetry," it should be interpreted as a geometry that does not have rotational symmetry, i.e., it does not have an axis of rotational symmetry.

[0042] Single-fold rotational symmetry is also commonly referred to as first-order discrete rotational symmetry, i.e., when rotating an object having a contour shape about any selected rotation axis, the contour shape only matches after a 360° rotation, i.e., only after a 360° rotation, the contour shape looks identical to the start of the rotation. In contrast, for example, in a rotationally symmetric contour shape with N-fold rotational symmetry (where N>1), the contour looks identical after a 360° / N rotation. A rotationally symmetric contour shape has an N-th order rotation axis (where N>1). In contrast to a rotationally symmetric contour shape with a rotation axis, a single-fold rotational symmetry does not have an axis of rotational symmetry such that after a rotation of 180° or less about the rotation axis, the rotated contour shape matches as it was in its initial position.

[0043] When the phrase "mirror symmetry" or "mirror symmetry" is used throughout this disclosure, it must be interpreted as reflection symmetry, i.e., when in three dimensions, a mirror-symmetric object or a mirror-symmetric profile has a mirror symmetry plane, also called a mirror plane. For each half of a mirror-symmetric object or profile on a first side of the mirror symmetry plane, there is another half of the object or profile on a second side of the mirror symmetry plane, such that each point of the half of the object or profile on the first side has an equidistant allocation to another point of the other half of the object or profile on the second side of the mirror symmetry plane. When in two dimensions, mirror symmetry implies the existence of an axis of symmetry, and when folding a two-dimensional object in half on the axis of symmetry, the two halves should be identical.

[0044] Safety Filter Element According to a first aspect of the present disclosure, a safety filter element is provided. The safety filter element is an element for backing up the failure of the main filter element with a primary filter media pack. The safety filter element and the main filter element are components installed in the housing of the filter system, for example, as shown in Fig. 7, which shows a housing 220 of a filter system 200 including a main filter element with a primary filter media pack 20 and a safety filter element with a secondary filter media pack 10. The main filter element and the safety filter element are structurally separate components in that the main filter element is removable from the housing without the need to remove the safety filter element.

[0045] 1a-1e, 3a-3d, 4a, and 4b, various example embodiments of a safety filter element 1 according to the present disclosure are shown and are discussed further below.

[0046] The safety filter element 1 comprises a secondary media pack 10 having a fluid inlet side 11, a fluid outlet side 12 opposite the fluid inlet side, and a peripheral side 13 extending in a longitudinal direction Y from the fluid inlet side to the fluid outlet side. In other words, the secondary media pack is a so-called straight flow filter device. In one embodiment, the direction Y in Figures 1b-1d can also be characterized as a central longitudinal axis of the safety filter element 1, which also defines a central longitudinal axis of the secondary media pack 10.

[0047] The secondary media pack 10 can comprise any suitable filter media. In an embodiment, the secondary media pack 10 comprises pleated media. In another embodiment, the secondary media pack 10 comprises fluted media. In an embodiment, the fluted media comprises, for example, a spiral layer of fluted media, with the outer surface of the outer layer of the spiral fluted media forming the peripheral side 13 of the secondary media pack 10. Typically, each of the spiral layers of fluted media comprises inlet and outlet grooves, preferably oriented essentially parallel to the longitudinal direction.

[0048] The safety filter element 1 further comprises a shell 40. The shell comprises a peripheral wall 49 extending in a longitudinal direction Y from a first opening 41 at a first end of the shell to a second opening 42 at a second end of the shell. The shell is also referred to as a casing. An inner first portion 46 of the peripheral wall 49 of the shell surrounds the peripheral side 13 of the secondary media pack 10, and an inner second portion 47 of the peripheral wall of the shell defines a radial boundary of a cavity 45 located between the first opening 41 of the shell and the fluid inlet side 11 of the secondary media pack. The cavity allows the shell to receive or at least partially receive the primary media pack of the main filter element.

[0049] 4a and 4b, an embodiment is shown in which the secondary media pack 10 is removable from the shell. In Fig. 4a, a first inner wall portion 46 and a second inner wall portion 47 of the shell are shown, as defined above. In an embodiment, after the cavity of the shell receives the primary media pack, a longitudinal spacing between the primary and secondary media packs may remain, which is shown in Fig. 4b, where the inner wall of the shell comprises a third wall portion 43 between the first wall portion 46 and the second wall portion 47.

[0050] The shell 40 advantageously not only protects the peripheral side of the secondary media pack from damage that may be caused by the housing body or during handling, but also protects the peripheral side of the primary media pack from damage when the main filter element is installed. Thus, there is no need to place a dedicated shell around the primary media pack. With reference to Figures 2a and 2b, a filter assembly 100 is shown that includes a safety filter element 1 and a main filter element 2, and after the main filter element 2 is installed, the shell 40 of the safety filter element completely surrounds the primary media pack.

[0051] The first inner wall portion 46 and the second inner wall portion 47 of the shell 40 do not necessarily have the same perimeter size. This is shown in Figures 3c and 3d, in which a cross section of an embodiment of a safety filter element is shown, with the first shell portion surrounding the secondary media pack having a smaller perimeter than the second shell portion defining the cavity for receiving the main media pack. For example, if the perimeter of the secondary media pack is different from the perimeter of the primary media pack, the shell 40 can be configured to have two shell portions with inner wall portions that match the outer perimeter of the primary media pack and the secondary media pack, respectively.

[0052] In an embodiment, the shell is made or is at least partially made from a thermoplastic material, preferably acrylonitrile butadiene styrene, polypropylene, polyamide, polyethylene terephthalate, polylactic acid, polyethylene, polycarbonate, polystyrene, or polyvinyl chloride, or any of their mixtures and combinations.

[0053] The safety filter element according to the present disclosure comprises at least a first seal member 31 supported by the shell 40. The first seal member 31 is a seal for sealing the safety filter element to the main filter element. In fact, since the safety filter element and the main filter element are separate components, when the main filter element is coupled with the safety filter element by inserting the primary filter media pack into the cavity of the safety filter element, a peripheral gap exists between the main filter element and the safety filter element. More specifically, the seal member 31 is a seal configured to seal the gap between the second portion 47 of the inner wall of the shell 40 and the primary filter media pack when the primary filter media pack is received in the cavity 45. In other words, the first seal member 31 ensures that the incoming dirty fluid, e.g. dirty air, filtered by the primary filter media pack does not bypass the primary filter media pack, and that the clean fluid, e.g. clean air, leaving the primary filter media pack flows further through the secondary filter media pack.

[0054] The first seal member 31 is a three-dimensional component of the safety filter element 1, and the first seal member generally comprises a number of peripheral sides. For example, there is at least one peripheral side of the first seal member that forms a sealed bond with the shell 40, more generally referred to as the first peripheral sealing portion 31a, and there is at least another peripheral side that forms a sealed bond with an external component, i.e., with the exterior of the safety filter element, in this case the main filter element, or more generally referred to as the second peripheral sealing portion 31b. The second peripheral sealing portion 31b of the first seal member 31 is that portion of the seal member that cooperates with the sealing surface of the main filter element when the cavity of the safety filter element receives the primary filter media pack of the main filter element. In other words, the second peripheral sealing portion 31b of the first seal member 31 is that portion that seals the peripheral gap between the main filter element and the safety filter element when the cavity of the safety filter element receives the primary filter media pack.

[0055] The safety filter element according to the present disclosure is characterized in that the second peripheral sealing portion 31b of the first seal member 31 has a contour shape that is rotationally symmetrical in a single turn. In other words, there is no axis of rotational symmetry for this contour shape. Thus, even for those embodiments in which the safety filter element includes a central longitudinal axis, the central longitudinal axis is not the axis of rotational symmetry for this contour shape. Thus, when installing the main filter element, there is only one way in which the primary filter media pack can be inserted into the cavity of the safety filter element such that the second peripheral sealing portion 31b of the first seal member coincides with the corresponding sealing surface of the main filter element.

[0056] In an embodiment, the first seal member 31 of the safety filter element 1 according to the present disclosure is permanently bonded to the shell 40. Permanently bonded should be interpreted as irremovably bonded. Thus, when the first seal member 31 needs to be replaced according to a maintenance procedure, at least the shell 40 needs to be replaced along with the first seal member 31. The first seal member 31 is permanently bonded to the shell 40 by sealingly attaching the first peripheral sealing portion 31a to the shell 40. This attachment can be performed, for example, using an adhesive such as glue. Alternatively, the first peripheral sealing portion 31a is sealingly attached to the shell 40 by using a multi-component injection molding technique when manufacturing the shell such that the shell 40 and the first seal member 31 form a single unit.

[0057] In other embodiments, the first seal member 31 is removably coupled to the shell, i.e., in these embodiments, the first seal member is a replaceable seal such that the first seal member can be replaced, for example, during a maintenance procedure, without having to replace the shell 40. In these embodiments, the first seal member 31 rests, for example, on a seal support flange 48 of the shell 40, or if the first seal member 31 is coupled to a peripheral wall 49 of the shell 40, a groove or recess can be made in the peripheral wall 49 to support the first seal member 31.

[0058] In an embodiment, for example as shown in Figures 1e, 2c, and 3b-3d, the shell 40 includes a seal support flange 48 disposed at a first end of the shell 40. The seal support flange 48 should be interpreted as a protruding collar or rim forming a support element for supporting the first seal member. The first seal member 31 is removably or permanently coupled to the seal support flange 48.

[0059] Generally, as shown in Figures 3b-3d, the seal support flange 48 has a peripheral support surface 48a, and the first peripheral sealing portion 31a of the first seal member 31 is coupled, either permanently coupled or removably coupled, to the peripheral support surface 48a.

[0060] In embodiments, as shown diagrammatically in Figures 3b and 3c, the seal support flange 48 projects radially relative to the longitudinal direction Y. In these embodiments, the support flange 48 comprises a peripheral support surface 48a for supporting the first seal member 31 that is essentially perpendicular to the longitudinal direction Y.

[0061] In another embodiment, as shown generally in Figures 1e, 2c, and 3d, the seal support flange 48 is disposed at an oblique angle relative to the longitudinal direction Y. This allows for compact integration of the safety filter element within the filter system housing 220 and can reduce impractical space between the safety filter element and the interior wall of the filter system housing.

[0062] 2c, 3d and 8, the seal support flange 48 comprises a peripheral support surface 48a for supporting the first seal member 31, the peripheral support surface 48a being arranged at an oblique angle relative to the longitudinal direction Y. This makes it possible to provide a compact first seal member geometry and to provide a compact integration of the safety filter element within the housing of the filter system.

[0063] In an embodiment, the first seal member 31 is made or at least partially made from any of rubber, thermoplastic elastomers, thermoset elastomers, and thermoplastic vulcanizates, or mixtures or combinations thereof.

[0064] Advantageously, in an embodiment, the first seal member 31 is overmolded to the shell 40 via injection molding, such that the shell and the first seal member form a single piece. Injection molding, or more precisely, multi-component injection molding, is a manufacturing process in which at least a first component and a second component of the multi-component injection molding process correspond to the material of the shell 40 and the material of the first seal member 31, respectively.

[0065] In a further embodiment, the first seal member 31 is made or at least partially made from a polyurethane (PU) material, for example to form a foamed polyurethane seal. The PU material may be moulded onto the shell 40, or alternatively the first seal member may be moulded solely from the PU material and further secured to the shell with an adhesive.

[0066] The safety filter elements of the present disclosure have in common that a first seal member 31 is coupled to a shell 40, although the location of the first seal member 31 relative to the shell 40 may vary depending on the embodiment. With reference to Figures 1a-1e, 3b, and 4a, examples of safety filter elements in which a first seal member 31 is coupled to a first end of a shell 40 are shown.

[0067] In embodiments in which the first seal member 31 is coupled to the first end of the shell 40, the first seal member 31 is configured to form an axial seal with respect to the longitudinal direction Y, for example as shown diagrammatically in Figures 3b and 3c. An axial seal is one that essentially seals axially, i.e., in a direction parallel to the longitudinal direction Y.

[0068] In a further embodiment, as shown diagrammatically in Fig. 3a, the first seal member 31 is coupled to the inner wall of the shell 40, more precisely to the second inner wall portion 47 of the shell. The first seal member 31 thus forms a radial seal with respect to the longitudinal direction. A radial seal is a seal which seals or at least partially seals radially, i.e. transversely with respect to the longitudinal direction Y.

[0069] 1a, a top view of an embodiment of a safety filter element is shown in which the first seal member 31 follows the contour of the shell 40, which in this example has the shape of a banana, i.e., a shape with single-fold rotational symmetry. Because the first seal member 31 follows the contour of the shell, which has single-fold rotational symmetry, the second peripheral sealing portion 31b of the first seal member also has a contour with single-fold rotational symmetry.

[0070] With reference to Fig. 5a, a first sealing member 31 is shown, comprising a first peripheral sealing portion 31a for sealing to the shell 40 and a second peripheral sealing portion 31b for sealing to the main filter element, the second peripheral sealing portion 31b having a single rotationally symmetrical outer shape. As shown in Fig. 5a, the single rotational symmetry is obtained by providing the sealing member 31 with a single axial step in the axial direction. In this example, the first sealing member 31 is an axial seal, for example for use with a safety filter element as shown in Fig. 3b or 3c, the first sealing member 31 being axially coupled to a seal support flange 48 of the shell. More precisely, the first peripheral sealing portion 31a opposite the second peripheral sealing portion 31b can be axially coupled to a peripheral support surface 48a of the flange 48. In this example, the shell 40 and / or the seal support flange 48 may have a rotationally symmetric shape, e.g. a circular outer shape, while the second peripheral sealing portion 31b has a single-fold rotationally symmetric outer shape. In the example shown in Fig. 5a, the first peripheral sealing portion 31a has an outer shape that is rotationally symmetric about the longitudinal axis Y.

[0071] With reference to Fig. 5b, a further embodiment of the first seal member 31 is shown, comprising a first peripheral sealing portion 31a for sealing to the shell 40 and a second peripheral sealing portion 31b for sealing to the main filter element, the second peripheral sealing portion 31b having an outer shape with single-fold rotational symmetry. In this example, the first seal member 31 has a strip shape, the second peripheral sealing portion 31b is inside the strip-shaped first seal member 31, and the first sealing portion 31a is outside the strip-shaped seal member 31. In this example, the first seal member 31 is a radial seal that can be used in combination with the safety filter element shown in Fig. 3a, for example, by bonding the outside of the strip-shaped seal member to the inside of the peripheral wall 49 of the shell 40. In this example, the inside of the peripheral wall 49 receiving the first seal member shown in Fig. 5b has two-fold rotational symmetry with respect to the longitudinal direction Y, while the outer shape of the second peripheral sealing portion 31b has single-fold rotational symmetry. In this example of a strip-shaped sealing member, both the first peripheral sealing portion 31a and the second peripheral sealing portion 31b have a single rotationally symmetric outer shape.

[0072] In embodiments, for example as shown in Figures 2a and 2c, the first seal member 31 is a lip-type seal member. A lip-type seal member is a seal member that includes at least one sealing lip 34. In these embodiments, the at least one sealing lip 34 forms the second peripheral sealing portion 31b of the first seal member 31.

[0073] The first seal member 31 of the safety filter element 1 of FIG. 2a is shown in more detail in FIG. 1e and FIG. 2c, where the first seal member 31 is colored black. As shown in FIG. 1e and FIG. 2c, the first seal member 31 is a lip seal with one sealing lip 34 in this example. As mentioned above, the sealing lip 34 forms a second peripheral sealing portion 31b for sealing the safety filter element to the main filter element. In this example, the first seal member 31 is bonded to the seal support flange 48, more precisely, the first peripheral sealing portion 31a is bonded to the seal support flange 48. In an embodiment, the first peripheral sealing portion 31a can be permanently bonded to the seal support flange 48 with an adhesive such as glue, or can be permanently bonded during the manufacturing process of the shell by injection molding. In another embodiment, the first seal member 31 is a removable seal member, and the first seal member rests on the seal support flange 48 at its first peripheral sealing portion 31a.

[0074] In an embodiment in which the first seal member 31 is a lip-type seal member comprising at least one sealing lip 34, the at least one sealing lip 34 is disposed at an oblique angle relative to the longitudinal direction Y, as shown in Figures 1e and 2c. This oblique angle exists when the sealing lip 34 is in an unsealed position. When in a sealed position, pressure acts on the sealing lip 34 such that the sealing lip bends further.

[0075] In an embodiment, as shown in FIG. 1e, at least one sealing lip 34 is inclined outwardly by an angle α with respect to the longitudinal direction Y. Preferably, the angle α is at least 5°, more preferably at least 10°. This angle is present when in the unsealed position. When in the sealed position, the angle can be even larger. For example, when the main filter element is inserted with the safety filter element and a cover or precleaner is placed on the housing of the filter system, the perimeter frame 23 of the main filter element exerts pressure on the beveled sealing lip such that the beveled sealing lip is further inclined outwardly to form a leak-proof seal between the safety filter element and the main filter element.

[0076] In an embodiment, in addition to the single-fold rotational symmetry of the contour of the second peripheral sealing portion of the first seal member 31, the contour of the second peripheral sealing portion 31b further has a plane of mirror symmetry M that traverses the fluid inlet and fluid outlet sides of the secondary media pack. In the example of the first seal member 31 shown in Figures 5a and 5b, the second peripheral sealing portion 31b has a plane of mirror symmetry designated by the letter M. When the first seal member 31 is bonded to the shell of the safety filter element, the plane of mirror symmetry M traverses the fluid inlet and fluid outlet sides of the secondary media pack.

[0077] In an embodiment, the contour of the second portion 47 of the inner wall of the shell 40 has single-fold rotational symmetry. For example, if the contour of the primary media pack has single-fold rotational symmetry, the contour of the second portion 47 of the inner wall of the shell can be configured to match the contour of the periphery of the primary media pack.

[0078] 1a-1e, not only does the first seal member 31 have a second peripheral sealing portion 31b that is a single-fold rotational pair, but the shell 40 itself also has single-fold rotational symmetry. In this embodiment, the outer shape of the second peripheral sealing portion 31b of the first seal member 31 follows the outer shape of the periphery of the outer peripheral wall of the shell 40. In this embodiment, the outer and inner outer shapes of the shell have single-fold rotational symmetry.

[0079] In another embodiment, the shell 40, or more precisely the peripheral wall 49 of the shell, can be rotationally symmetrical with respect to an axis of rotation parallel to the longitudinal direction Y. As mentioned above, the first sealing member 31 can be coupled to the end of the shell, for example as shown diagrammatically in FIG. 3b. As mentioned above, an example of a first sealing member 31 in which the outer shape of the second peripheral sealing part has single-fold rotational symmetry and which can be coupled to a rotationally symmetric shell is shown in FIG. 5a. Such a first sealing member forms, for example, an axial seal for sealing in an axial direction parallel to the longitudinal direction.

[0080] In an embodiment, the shell has discrete N-fold rotational symmetry about an axis of rotation parallel to the longitudinal direction Y, where N>1.

[0081] An example of a first sealing member 31 in which the outer shape of the second peripheral sealing portion 31b has single-fold rotational symmetry and can be used in combination with a shell having two-fold rotational symmetry about an axis of rotation parallel to the longitudinal direction is shown in Figure 5b.

[0082] In an embodiment, the cross section between the outside of the peripheral wall 49 of the shell 40 and a plane transverse to the longitudinal direction Y has a shape selected from any of a circle, an oval, a racetrack shape, a peanut shape, a banana shape, an ellipse shape, a square shape, and a rectangle.

[0083] In an embodiment, the cross section between the inner second portion 47 of the peripheral wall 49 of the shell 40 and a plane transverse to the longitudinal direction Y has a shape selected from any of a circle, an oval, a racetrack shape, a peanut shape, a banana shape, an ellipse shape, a square shape, and a rectangle.

[0084] In an embodiment, a safety filter element according to the present disclosure comprises a connection structure 50 coupled to the shell 40 and configured for locking the safety filter element 1 in the housing of the filter system. In this way, during a maintenance procedure, when the main filter element is replaced, the connection structure keeps the safety filter element locked in place in the housing of the filter system.

[0085] In embodiments, the connection structure 50 comprises any one or combination of one or more latches, one or more snap fit connectors, one or more pivoting connectors, one or more hinges, or one or more screws.

[0086] The connecting structure 50 may be bonded to the shell with an adhesive, or the connecting structure 50 may be bonded to the shell by injection molding as part of the manufacturing process of the shell.

[0087] 1b, 1d, and 1e, an example is shown in which the connection structure 50 comprises two pivot connectors 50a, 50b coupled to the shell, each of the pivot connectors being movable from a first position to a second position such that when in the first position the safety filter element is removable from the housing of the filter system, and when in the second position the pivot connectors engage with corresponding engaging elements on the exterior of the housing to form a locked connection between the safety filter element and the housing.

[0088] In an embodiment, as shown in Fig. 1e, the pivot connector 50a can pivot about a pivot axis 50c. In this embodiment, the pivot connector is made from a plastic material and is manufactured as part of the shell manufacturing process, and the pivot axis is obtained by locally reducing the thickness of the plastic material, as shown in Fig. 1e.

[0089] In other embodiments, the connection structure of the safety filter element comprises one or more engagement elements configured to engage with corresponding connector elements of the housing of the filter system to lock the safety filter element to the housing of the filter system. Examples of engagement elements are a notch, a slot, a recess, one or more latch receptacles for engaging with one or more corresponding latches, or one or more snap fit receptacles for engaging with one or more corresponding snap fit connectors.

[0090] In an embodiment, a safety filter element according to the present disclosure includes a second seal member 32 coupled to the shell 40. Preferably, the second seal member 32 is coupled to an exterior of the peripheral wall 49 of the shell 40, as shown generally in Figures 3a-3d.

[0091] The second seal member is a seal member for sealing the safety filter element to the housing of the filter system. In fact, when the safety filter is installed in the housing of the filter system, the second seal member 32 seals to a sealing surface of the housing of the filter system. Advantageously, the second seal member 32 ensures that incoming dirty fluids, e.g. dirty air, do not bypass the primary and secondary media packs through the gap between the outside of the peripheral wall 49 of the shell and the inner wall of the housing.

[0092] In embodiments, the second seal member 32 is permanently, i.e., non-removably, bonded to the shell. In other embodiments, the second seal member 32 is a removable seal member, such as a gasket.

[0093] 1a to 1d, the second seal member 32 is a lip-type seal member having one or more sealing lips 32a, 32b as shown in Fig. 2c. The sealing lips 32a, 32b are sealing lips for sealing to a housing.

[0094] 2c, the second seal member 32 includes an inner peripheral side 35a for sealing to the shell 40 and an outer peripheral side 35b for sealing to the housing, with the inner peripheral side 35a being bonded to the outside of the peripheral wall 49 of the shell 40. Generally, with this type of seal geometry, the second seal member radially seals, or at least partially radially seals, the safety filter element to the housing of the filter system.

[0095] In an embodiment, the outer peripheral side 35b of the second seal member 32 is provided with one or more sealing lips 32a, 32b for sealing to the housing.

[0096] In an embodiment, the second seal member 32 is made or at least partially made from any of rubber, thermoplastic elastomers, thermoset elastomers, and thermoplastic vulcanizates, or mixtures or combinations thereof. The second seal member 32 may be overmolded onto the shell 40, for example, via multi-component injection molding.

[0097] In an embodiment, both the first seal member 31 and the second seal member 32 are overmolded onto the shell via injection molding, thus resulting in a robust, unitary safety filter element comprising at least the shell and both the first and second seal members.

[0098] In a further embodiment, the second seal member 32 is made, or at least partially made, from a polyurethane material.

[0099] In embodiments, the secondary media pack 10 is not removable from the shell 40. In these embodiments, the periphery of the secondary media pack 10 is sealingly attached to the inner first portion 46 of the periphery of the shell, for example, by using an adhesive or by using an overmolding manufacturing process.

[0100] In other embodiments, as shown generally in Figures 4a and 4b, the secondary media pack 10 is removable from the shell so that it can be replaced without replacing the shell. In these embodiments, the safety filter element includes a third seal member 33 configured to seal a gap between the peripheral side 13 of the secondary media pack 10 and the first portion 46 of the inner wall of the shell 40.

[0101] In an embodiment, as shown in Figures 1b and 2a, the seal support flange of the shell 40 includes one or more first positioning elements 55 for facilitating accurate positioning of the main filter element 2 within the safety filter element cavity 45. The first positioning elements 55 are configured to engage corresponding second positioning elements disposed on the main filter element 2. The positioning elements 55 facilitate positioning of the main filter element within the safety filter element cavity.

[0102] In embodiments, the one or more first positioning elements 55 comprise any one or combination of a notch, a dimple, a recess, a ridge, a groove, or a slot.

[0103] In an embodiment, as shown in FIG. 3b, the safety filter element 1 comprises one or more rib elements 26 positioned essentially parallel to the fluid inlet side 11 of the secondary filter media pack. Such a safety filter element with rib elements 26 is generally used in combination with a main filter element in which the filter media pack comprises grooves. In fact, the one or more rib elements 26 act as an anti-tension frame to prevent the movement of the spiral layer of the primary grooved filter media pack in the longitudinal direction Y. This movement in the longitudinal direction is generally known as tension and can result, for example, from the pressure difference between the inlet and outlet of the filter element or as a result of vibration. Thus, the safety filter element with rib elements 26 according to the present disclosure does not require the addition of a dedicated anti-tension frame to the main filter element, thus further simplifying the manufacturing process of the main filter element.

[0104] Filter Assembly According to a second aspect of the present disclosure, there is provided a filter assembly 100 comprising a safety filter element 1 according to the present disclosure and a main filter element 2. The main filter element 2 can be inserted and removed from a cavity of the safety filter element. In Figures 2a and 2b, an example embodiment of the filter assembly is shown, where the main filter element 2 is removed from the cavity of the safety filter element 1 and the main filter element 2 is inserted into the cavity of the safety filter element 1, respectively.

[0105] Referring to Figure 6, an example embodiment of a main filter element is shown. The main filter element shown in Figure 6 is an example embodiment of a main filter element that can be inserted into the safety filter element shown in Figures 1a-1e.

[0106] The main filter element 2 of the filter assembly 100 includes a primary filter media pack 20 receivable in the cavity 45 of the safety filter element.

[0107] Typically, the primary media pack 20 has an outer circumferential surface extending in a longitudinal direction Y between a fluid inlet face 21 and a fluid outlet face 22 opposite the fluid inlet face 21. The main filter element 2 is configured such that when the primary media pack 20 is received in the cavity of the safety filter element, the fluid outlet face 22 of the primary media pack faces the fluid inlet side 11 of the secondary media pack. Thus, in these embodiments, the primary media pack should be construed as a flow-through media pack.

[0108] In an embodiment, the filter assembly mating with the primary media pack 20 comprises a fluted media. In an embodiment, the fluted media comprises, for example, a spiral layer of fluted media, with the outer surface of the outer layer of the spiral fluted media forming the outer periphery of the primary media pack 20. Typically, each of the spiral layers of fluted media of the primary media pack 20 comprises inlet and outlet grooves, preferably oriented essentially parallel to the longitudinal direction Y.

[0109] 6, the main filter element 2 further includes a peripheral frame 23 sealingly attached to the primary media pack 20. The peripheral frame 23 includes a peripheral sealing surface configured for sealingly cooperating with the first seal member 31 when the primary media pack is received in the cavity 45.

[0110] The perimeter frame 23 is sealingly attached to the primary media pack 20, for example, attached to the outer periphery of the primary media pack. Attachment can be accomplished by a variety of means, for example, by heat welding or by using an adhesive.

[0111] In an embodiment, as shown in FIG. 6, the main filter element 2 includes one or more handles 24 to facilitate manipulation of the main filter element during maintenance.

[0112] As mentioned above, in embodiments, the shell 40 of the safety filter element 1 comprises one or more first positioning elements 55 configured for engaging with corresponding second positioning elements 25 disposed on the main filter element 2 to facilitate accurate positioning of the main filter element 2 on the safety filter element 1. In the embodiment shown in Figure 6, the main filter element 2 further comprises second positioning elements 25 for engaging with the first positioning elements 55 of the safety filter element 1.

[0113] Filter System According to a third aspect of the present disclosure, there is provided a filter system comprising a filter assembly as described above and a housing for accommodating the filter assembly.

[0114] Referring to Figure 7, there is shown a filter system 200 comprising a housing 220 housing a filter assembly according to the present disclosure, namely a filter assembly comprising a main filter element and a safety filter element. In this example, the filter system 200 comprises the filter assembly shown in Figure 2a. In the embodiment shown in Figure 7, the filter system also comprises a precleaner 225 for precleaning fluid before it enters the primary filter media pack 20 of the main filter element.

[0115] Referring to Figure 8, there is shown a cross-sectional view of a portion of the filter system of Figure 7, showing a first seal member 31 for sealing to the main filter element 2 and a second seal member 32 for sealing to the inner wall of the housing 220. In this example, the first seal member 31 is a lip seal supported on the inclined flange 48 of the shell 40, the lip seal comprising a sealing lip 34 forming a second peripheral sealing portion 31b of the first seal member 31. The sealing lip 34 cooperates with a peripheral sealing surface of the peripheral frame 23 of the main filter element 2. In this example, the second seal member 32 is also a lip seal, comprising two lips 32a and 32b which cooperate with the inner wall of the housing 220.

[0116] In addition to the housing 220 and the filter assembly, the filter system shown in Figures 7 and 8 also includes a precleaner 225. Precleaners are known in the art and are disclosed, for example, in US Patent Application Publication No. 2018 / 0369735 A1. Precleaners remove most of the contaminants and dust from the incoming air before the air enters the main filter element. In general, precleaners are effective at removing larger dust particles and water droplets. As a result, they greatly reduce the dust that reaches the air cleaner, which in turn extends the life of the main filter element.

[0117] In an embodiment, as shown in FIG. 8, after the installation of the precleaner, the press element 226 of the precleaner 225 is pressed against the peripheral frame 23 of the main filter element 2. In this way, the first seal member 31 remains uniformly compressed over its entire circumferential length to provide a leak-proof seal between the safety filter element and the main filter element. The press element of the precleaner can be, for example, a peripheral rib that follows the contour of the peripheral frame 23 of the main filter element, or a number of smaller rib sections. In these embodiments, the axial force exerted by the press element 226 is obtained by locking the precleaner to the housing of the filter system when the precleaner is installed. An example of a connector is a latch. Usually, one or more connectors, for example latches, are used to lock the precleaner to the housing.

[0118] In an embodiment, the precleaner includes one or more latches for locking the precleaner to the housing of the filter system.

[0119] In another embodiment, the filter system comprises a cover instead of the precleaner, which is engaged with the housing of the filter system by one or more connectors. After installation of the cover by the connectors, a pressing element of the cover is pressed against the peripheral frame 23 of the main filter element 2. In this way, the first sealing member 31 remains uniformly compressed over its entire circumferential length. The pressing element of the cover is, for example, a peripheral rib or the pressing element consists of a number of rib sections.

[0120] In embodiments, after insertion of the main filter element into the safety filter element, in order to ensure sealing compression of the first sealing member 31, the main filter element is locked to the safety filter element by a locking means. The locking means are, for example, a number of screws for screwing the main filter element to the safety filter element. Alternatively, the locking means may comprise a snap-fit ​​connection between a first snap-fit ​​component and a second snap-fit ​​component, where the first component is arranged on the safety filter element and the second component is arranged on the main filter element, both components being suitable to provide a snap-fit ​​connection when the main element is received in or by the safety filter element. In these embodiments, the main filter element remains sealingly locked with the safety filter element even after removing the precleaner or after removing the cover.

[0121] 9-37 show preferred embodiments of a fluid cleaner assembly, preferably an air cleaner assembly, of the present disclosure, a safety filter element, a main filter element, and a housing (including housing components and a precleaner or cover component).

[0122] It is contemplated that all preferred and optional features and combinations of features described for any of the preceding embodiments are applicable to the embodiment described in relation to Figures 9-37.

[0123] It is also contemplated that the preferred and optional features and combinations of features described with respect to the following description of Figures 9-37 are applicable to other embodiments of the present disclosure mutatis mutandis, where and where necessary.

[0124] In the following description, the same reference numbers refer to the same or similar features as described above. Not all reference numbers are provided in all drawings.

[0125] The preferred embodiment disclosed comprises a filter assembly 100 comprising a safety filter element 1, a main filter element 2, and a housing 220 comprising a main portion and a cover or precleaner portion 225.

[0126] The safety filter element 1 is provided to back up the failure of the main filter element with the primary filter media pack. The safety filter element 1 comprises a secondary filter media pack 10, preferably a pleated filter media pack, having a peripheral side 13 extending in the longitudinal direction Y from a fluid inlet side 11 to a fluid outlet side 12. The safety filter element 1 further comprises a shell 40 with a peripheral wall 49 extending in the longitudinal direction Y from a first opening 41 at a first end of the shell to a second opening 42 at a second end of the shell. An inner first portion 46 of the peripheral wall 49 surrounds the peripheral side 13 of the secondary filter media pack 10. An inner second portion 47 of the peripheral wall 49 defines a radial boundary of a cavity 45 arranged between the first opening of the shell 41 and the fluid inlet side 11 of the secondary filter media pack for receiving or at least partially receiving the primary filter media pack of the main filter element. A first seal member 31 is provided comprising a first peripheral sealing portion 31a for sealing to the shell 40 and a second peripheral sealing portion 31b, 34 for sealing to the peripheral frame 23 of the main filter element 2, in particular to a corresponding peripheral frame sealing surface 231. The second peripheral sealing portion 31b, 34 has a single-fold rotationally symmetric outer shape. Similarly, the peripheral frame sealing surface 231 has a single-fold rotationally symmetric outer shape.

[0127] Preferably, the shell 40 comprises or is made of a plastic. Preferably, the seal member 31 comprises or is made of a thermoplastic elastomer.

[0128] The first seal member 31 is permanently bonded to the shell 40 by sealingly attaching the first peripheral sealing portion 31a to the shell 40, for example by overmolding onto the shell 40 via multi-component injection molding.

[0129] The first seal member 31 is a lip-type seal member with one sealing lip 34 which forms a second peripheral sealing portion 31 b of the first seal member 31 .

[0130] The shell 40 includes a seal support flange 48 that supports the first seal member 31. The support flange 48 is disposed at a first end of the shell 40 and extends perpendicular to the longitudinal direction Y of the shell.

[0131] The seal support flange 48 includes a peripheral support surface 48a, and the first peripheral sealing portion 31a of the first seal member 31 is coupled to the peripheral support surface 48a.

[0132] The support flange further includes a seal support flange extension 481 extending from the outer periphery of the flange 48 in a direction parallel to the longitudinal direction Y toward the secondary media pack 10. In one particular illustration, the first end of the shell 40 is bent rearwardly, thereby defining a U-shaped, peripheral, annular recess 56 (e.g., a third positioning element). The support flange extension 481 is provided with a second seal member 32 on its radially outer surface.

[0133] The second peripheral sealing portion 31b, 34 of the first seal member 31 is configured for axial sealing or at least partially axial sealing relative to the longitudinal direction Y.

[0134] The safety filter element includes a second seal member 32 for sealing the safety filter element to the housing of the filter system. The second seal member 32 is permanently bonded to the shell 40. More specifically, the second seal member 32 is bonded to the exterior of the peripheral wall 49 of the shell 40, and in particular to the radially outer surface of the support flange extension 481.

[0135] The second seal member 32 includes an inner peripheral side surface 35a for sealing to the shell 40 (extension 481) and an outer peripheral side surface 35b for sealing to the housing. The inner peripheral side surface 35a is coupled to the outside of the peripheral wall 49 of the shell 40, in particular to the support flange extension 481.

[0136] The second seal member 32 is a lip-type seal member with two sealing lips 32a, 32b for sealing to the housing. Adjacent to one or more of the lips, for example between the two lips, a seal member compression limiting element(s) 32s is provided to stop the compression of the lip seal at a predetermined height. The outer peripheral side 35b of the second seal member 32 includes two sealing lips 32a, 32b separated by a single seal member compression limiting element 32s. It preferably comprises a thermoplastic elastomer and is preferably formed by overmolding onto the shell 40 via multi-component injection molding.

[0137] As an optional feature, the safety filter element includes a fourth seal member 36 for sealing the safety filter element to the cover or precleaner 225 housing of the filter assembly. The fourth seal member 36 is permanently bonded to the shell 40, for example, to the flange surface 48a of the shell 40 or to the support flange extension 481. The fourth seal member 36 is a lip seal having one lip. The lip has a predominant axial sealing component for axial sealing with a corresponding surface of the cover or precleaner. It may also have a radial component. Alternatively, it may include multiple lips. The fourth seal member 36 is circumferentially disposed between the first peripheral seal member 31 and the second peripheral seal member 32. For example, the lip of the fourth seal member 36 may be disposed at the junction between the support flange 48 and the support flange extension 481. For example, the lip of the fourth seal member 36 may be oriented away from the filter media pack 10. The lip of the fourth seal member 36 may form an angle with the lip of the first seal member 31 that is different from zero.

[0138] The peripheral side 13 of the secondary media pack 10 is sealingly attached to an inner first portion 46 of the peripheral wall 49 of the shell.

[0139] The outer shape of the second peripheral sealing portion 31 b , 34 of the first seal member 31 has a mirror symmetrical plane transverse to the fluid inlet side 11 and the fluid outlet side 12 of the secondary media pack 10 .

[0140] The cross section between the inner second portion 47 of the peripheral wall 49 of the shell 40 and a plane transverse to the longitudinal direction Y has an oval shape.

[0141] 37, the shell 40 includes one or more third positioning elements 56 (e.g., defined by a U-shaped recess) configured to facilitate positioning in the housing and for relative fixation of the safety filter element to the housing. For example, the U-shaped recess 56 of the safety filter may receive an axially extending protrusion or tab 2201 (e.g., a positioning element) of the housing 220 when the safety filter element is received in the housing. Interaction of the one or more recesses 56 with the fourth positioning elements 2201, e.g., one or more axially extending protrusions 2201, may function for guiding and radial alignment as well as radial fixation.

[0142] The main filter element 2 comprises a primary media pack 20, preferably a fluted media pack, receivable in the cavity 45 of the safety filter element 1. The main filter element 2 further comprises a peripheral frame 23 sealingly attached to the primary media pack 20. The peripheral frame 23 comprises a peripheral sealing surface configured for sealingly cooperating with the second peripheral sealing portion 31b of the first seal member 31 when the primary media pack 20 is received within the cavity 45. The peripheral frame 23 is sealingly attached to an outer peripheral surface of the primary media pack 20. The peripheral frame 23 of the main filter element 2 comprises a peripheral frame sealing surface 231. The peripheral frame sealing surface 231 preferably has an outer shape with single-fold rotational symmetry and corresponds to the single-fold rotational symmetry of the second peripheral sealing portion 31b, 34 of the safety filter element 1.

[0143] In one embodiment, the single-fold rotational symmetry of the second peripheral sealing portion 31b, 34 can be achieved regardless of the filter cartridge shape having the sealing portion deviating in the axial direction. For example, as most easily seen in FIG. 19, the second peripheral sealing portion 31b, 34 can include a main portion(s) 31b-1 with one or more axially deviating portions 31b-2 provided in an asymmetric arrangement (e.g., on a first side of the shell 40 but not on the opposite side of the shell 40). For example, as seen in FIG. 26, the peripheral frame 23 and corresponding sealing surface are provided with corresponding axially deviating portions 23a that axially follow the contour defined by the axially deviating portion 31b-2 of the sealing portion 31b. In one embodiment, the axially deviating portion 31b-2 allows the second peripheral sealing portion 31b, 34 to have a single-fold rotational symmetry while following the oval contour defined by the main filter element 2 and corresponding shell cavity 45. In the illustrated example, two similarly shaped axial deviation portions 31b-2 and 23 are shown and are provided on one side of the shell 40, in this case one of the long sides of the shell 40. However, other locations and other numbers are possible, e.g., more than one or two. In some embodiments, the axial deviation portions 31b-2 and 23a may be characterized as having a trapezoidal shape. Other shapes are possible. In some embodiments, the axial deviation portions 31b-2 and 23a are shown as extending in a direction from the main portion 31b-1 to the fluid inlet side 11. Alternatively, the portions 31b-2 and 23a may be configured to extend in the opposite direction. The second peripheral sealing portion 31b, 34 may be provided with axial deviation portions on the opposite long side wall of the shell 40 from that shown in the drawings, whereby single-fold rotational symmetry can be achieved by having differently shaped and / or different numbers of asymmetrically arranged axial deviation portions 31b-2. With continued reference to Figures 19 and 26, the second peripheral sealing portion 31b, 34 is provided with an additional axial deviation portion 31b-3 located at the longitudinal end of the shell 40 which is received by a corresponding axial deviation portion 23b on the filter cartridge frame 23.In the example shown, the axial deviation portions 31b-3, 23b are similarly shaped at each end. However, the two portions 31b-3, 23b can be provided with shapes that differ from each other in order to give the second peripheral sealing portion 31b, 34 a shape with single-fold rotational symmetry, independent of the axial deviation portion 31b-2.

[0144] The filter assembly further includes a precleaner 225 (only partially shown) or cover that can be locked to the remainder of the housing 220 with one or more connectors.

[0145] When the precleaner or cover 225 is installed, the fourth seal member 36 of the safety filter element 1 seals against the inner surface of the precleaner or cover 225 .

[0146] Although the figures shown and discussed above specifically address embodiments of filter elements for filtering air, the present disclosure is not limited to filter elements for filtering any particular fluid.

[0147] In an embodiment according to the present disclosure, the fluid is a gas, such as, for example, air. [Explanation of symbols]

[0148] 1 Safety Filter Element 2 Main filter element 10 Secondary Filter Media Pack 11 Fluid inlet side 12 Fluid outlet side 13 Circumferential side 20 Primary filter media packs 21 Fluid inlet surface 22 Fluid outlet surface 23 Surrounding Frame 23a Axial deviation 23b Axial deviation 24 Handle 25 Second Positioning Element 26 Rib elements 31 First seal member 31a first peripheral sealing part 31b Second peripheral sealing part 31b-1 Main section 31b-2 Axial deviation part 31b-3 Axial deviation part 32 Second seal member 32a, 32b Sealing lips of the second seal member 32s Second seal member compression limiting element 33 Third seal member 34 Sealing lip of first seal member 35a: inner peripheral side surface of the second seal member 35b Outer peripheral side surface of second seal member 36 Fourth sealing member 40 Shell 41 First opening of shell 42 Second opening of shell 43 Third wall section 45 Cavity 46 First part of inner wall 47 Second part of the inner wall 48 Seal support flange 48a Peripheral support surface 49 Shell Wall 50 Connection structure 50a, 50b Pivot connector 50c pivot axis 55 First Positioning Element 56 Third Positioning Element 100 Filter Assembly 200 Filter System 220 Housing 225 Precleaner 226 Press Elements 231 Periphery frame sealing surface 481 Seal Support Flange Extension 2201 Fourth Positioning Element

Claims

1. A safety filter element (1), a secondary filter media pack (10) having a peripheral side surface (13) extending in a longitudinal direction (Y) from a fluid inlet side (11) to a fluid outlet side (12); A safety filter element (1) comprising: a shell (40) comprising a peripheral wall (49) extending in the longitudinal direction (Y) from a first opening (41) at a first end of the shell to a second opening (42) at a second end of the shell, an inner first portion (46) of the peripheral wall (49) surrounding the peripheral side (13) of the secondary filter media pack (10), and an inner second portion (47) of the peripheral wall (49) radially delimiting a cavity (45) located between the first opening of the shell (41) and the fluid inlet side (11) of the secondary filter media pack (10), the cavity being suitable for receiving or at least partially receiving a primary filter media pack (20) of a main filter element (2); a first sealing member (31) comprising a first peripheral sealing portion (31 a) for sealing to said shell (40) and a second peripheral sealing portion (31 b) suitable for sealing to said main filter element (2), said second peripheral sealing portion (31 b, 34) having an outer shape with single rotational symmetry with respect to said longitudinal direction (Y); Further comprising: Safety filter element (1).

2. A safety filter element (1) as described in claim 1, wherein the first sealing member (31) is a lip-type sealing member having at least one sealing lip (34), and the at least one sealing lip (34) forms the second peripheral sealing portion (31b) of the first sealing member (31).

3. A safety filter element (1) as described in claim 1, wherein the first peripheral sealing portion (31a) of the first sealing member (31) is joined to the peripheral wall (49) of the shell, preferably at the first end of the shell (40).

4. A safety filter element (1) as described in claim 1, wherein the first peripheral sealing portion (31a) of the first sealing member (31) is joined to the inner second portion (47) of the peripheral wall (49) of the shell (40).

5. A safety filter element (1) as described in claim 1, wherein the second peripheral sealing portion (31b, 34) of the first sealing member (31) is configured to seal axially or at least partially axially relative to the longitudinal direction (Y).

6. A safety filter element (1) as described in claim 1, wherein the second peripheral sealing portion (31b) of the first sealing member (31) is configured to seal radially or at least partially radially relative to the longitudinal direction (Y).

7. A safety filter element (1) as described in claim 1, comprising a connection structure (50) for locking the safety filter element (1) to a housing of a filter system, the connection structure (50) being coupled to the shell (40).

8. A safety filter element (1) as described in claim 1, comprising a second sealing member (32) for sealing the safety filter element to a housing of a filter system, the second sealing member (32) being permanently or alternatively removably joined to the shell (40), preferably the second sealing member (32) being joined to the outside of the peripheral wall (49) of the shell (40).

9. A safety filter element (1) as described in claim 1, wherein the peripheral side (13) of the secondary filter media pack (10) is sealingly attached to the inner first part (46) of the peripheral wall (49) of the shell (40).

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