Safety filter element, filter system and filter assembly

Abstract

A safety filter element (1) suitable for use in a filter assembly includes a safety filter media (6) at least partially enclosing a safety filter media interior space (14) and at least one safety filter element end cap (13) having an outlet opening (15) leading to the safety filter media interior space. The safety filter element end cap includes a safety filter element circumferential support structure whereby a sealing component (11) is disposed on and extends along the safety filter element circumferential support structure, and the safety filter element end cap includes a housing sealing component (12).

Description

[Technical field]

[0001] (Reference to Related Application) This application was filed as a PCT international patent application on April 22, 2022, and claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 282,621, filed on November 23, 2021, which is incorporated by reference in its entirety herein.

[0002] (Technical field) The present disclosure relates to filter configurations, typically for use in filtering air, such as intake air for an internal combustion engine, and more particularly to filter assemblies disposed within a housing to provide a desired filtering capacity. [Background technology]

[0003] In various systems, air or other gas filtering is desirable or necessary. Examples of such systems include air intakes to internal combustion engines and crankcase ventilation filter assemblies. These filter assemblies may include one or more filter cartridges. For example, a first (main) filter cartridge may be the primary filtering element, and a second (safety) filter cartridge may be used in conjunction with the first filter cartridge, such as by inserting the second filter cartridge into the first filter cartridge. When the first and second filter cartridges have such a nested configuration, the cartridges are configured to align and seal to each other and / or to an air cleaner housing / clean air duct / housing cover for such operation on a vehicle.

[0004] From US Pat. No. 10,682,597 B2 a filter assembly is known which comprises a safety filter element (called the second media pack 1064 in the context of FIG. 3 of said reference) and a main filter element (called the filter media pack 1026).

[0005] From WO 2017 / 106752 A1, an air filter cartridge is known that includes a media pack having a media pack periphery, the media pack including a media having opposing inlet and outlet flow ends, a seal arrangement is provided that surrounds the media pack periphery, the seal arrangement including a radially oriented first seal segment within at least one mating radially oriented offset seal segment that extends away from the first seal segment in a direction toward one of the inlet and outlet flow ends.

[0006] From WO 2021 / 188967 A1 a filter element for insertion into a housing of a filter system is known, whereby the filter element comprises a filter media pack for filtering a fluid, the filter element having an outer circumferential surface extending between a first outer axial surface and a second outer axial surface opposite the first outer axial surface, the filter element further comprises a seal receiver sealingly attached to the filter media pack, the seal receiver comprising a closed loop surface for receiving a removable circumferential seal member, whereby said closed loop surface forms a contour shape with single-fold rotational symmetry.

[0007] A filter assembly such as that described in US Pat. No. 10,682,597 B2 uses a safety filter element when the main filter element needs to be replaced, for example to protect elements such as an internal combustion engine or a turbine, which in that case is arranged downstream of the filter assembly. If the safety filter element, which precisely prevents this, is missing when the main filter element is removed from the housing of the filter assembly, there is a risk that debris will pass through the housing, leave the housing through the outlet opening of the housing and proceed further towards elements arranged downstream of the filter assembly, with the risk of causing substantial damage to these elements. With the safety filter element in place, the main filter element can be removed from the housing and replaced with a new main filter element without the risk that debris will pass through the housing of the filter assembly and leave the housing at the outlet opening. Such debris is captured by the safety filter element. Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention relates to a safety filter element suitable for use in a filter assembly. The present invention also relates to a filter system including such a safety filter element and a main filter element. The present invention also relates to a filter assembly including such a safety filter element and a housing. The present invention also relates to a method of assembling a filter assembly. The present invention also relates to a method for replacing a main filter element in a filter assembly.

[0009] Considering the above background, the problem to be solved by the present invention is to provide a safety filter element, a filter system, a filter assembly, a method of assembling a filter assembly, and / or a method of replacing a main filter element in a filter assembly that provides increased security in preventing unfiltered fluid from exiting the filter assembly and / or that can be manufactured in a more environmentally friendly manner. [Means for solving the problem]

[0010] This problem is solved by a safety filter element according to claim 1, a safety filter element according to claim 7, a filter system according to claim 8, a filter system according to claim 10, a filter assembly according to claim 18, a filter assembly according to claim 19, a method for assembling a filter assembly according to claim 29 and a method for replacing a main filter element in a filter assembly according to claim 30. Preferred embodiments are discussed in the dependent claims and the subsequent description.

[0011] The invention is based on the general idea of ​​providing a safety filter element with a sealing component suitable for sealing the main filter element and a housing sealing component suitable for sealing the housing. Thus, instead of providing the main filter element with a seal for sealing the safety filter element, according to the invention the safety filter element has one sealing component for sealing the main filter element.

[0012] This general concept of the present invention may be specifically realized by providing at least one safety filter element end cap, whereby the safety filter element end cap includes a safety filter element circumferential support structure, whereby a sealing component is disposed on and extends along the safety filter element circumferential support structure to additionally provide the safety filter element end cap with a housing sealing component.

[0013] A filter element designed in such a way can be used to seal the main filter element, especially in those embodiments where the safety filter element is at least partially disposed inside the main filter element. Thus, in those designs where the safety filter element is at least partially disposed inside the main filter element, the sealing components that can be used to seal the main filter element to the safety filter element are provided on the safety filter element and remain with the safety filter element even if the main filter element is replaced.

[0014] The invention utilizes the idea that the sealing component that seals the main filter element against the safety filter element can be made of a material that lasts much longer than the main filter medium. The invention is based on the idea that in typical use cases the main filter medium, and therefore the main filter element, needs to be replaced more frequently than the sealing component. Typically the main filter element needs to be replaced because the main filter medium is defective or clogged much earlier than the sealing component needs to be replaced. Typically the sealing component lasts much longer than the main filter medium. The invention here works with the idea of ​​arranging the sealing component that seals the safety filter element against the main filter element on the safety filter element, and not on the main filter element. Then, even in the situation where the main filter element needs to be replaced, the sealing component remains on the safety filter element in the filter assembly. This has cost and ecological advantages. In the prior art where the sealing component is arranged on the main filter element, the fully functional sealing component is replaced and typically discarded together with the main filter element, since the main filter medium has reached its maximum lifespan. However, the sealing components in these situations would typically still be functional and would not have needed to be replaced. Thus, in the prior art, the still fully functional sealing parts are discarded, which results in higher costs and is not environmentally friendly. The present invention solves these problems because the sealing components remain in the filter assembly with the safety filter element, allowing the sealing components to be used for a longer period of time.

[0015] The present invention relates to a safety filter element, which is itself a marketable object that can be sold to customers who have filter assemblies in order to implement the present invention anew. The present invention is already manifested in the safety filter element itself.

[0016] The present invention also relates to a filter system comprising a safety filter element according to the present invention and a main filter element comprising a main filter medium. The filter system comprising the main filter element and the safety filter element is a marketable system that can be sold to customers who already have a filter assembly to newly implement the present invention. Thus, the filter system is also a method of implementing the present invention and an object that represents the present invention.

[0017] The present invention also relates to a filter assembly comprising a safety filter element according to the present invention and a housing. Such a filter assembly is itself a marketable item: it can be sold to customers who already have a main filter element and who are able to place an already existing main filter element into such a filter assembly.

[0018] The safety filter element extends along a longitudinal axis. In a preferred embodiment, the longitudinal axis is an axis of symmetry for at least one element that makes up the safety filter element, such as the safety filter media. However, designs are feasible in which the longitudinal axis is not an axis of symmetry for any of the elements that make up the safety filter element.

[0019] A safety filter element according to one aspect of the invention includes a safety filter media. The filter media at least partially encloses a safety filter media interior space. In a preferred embodiment, the safety filter media extends between first and second opposing media ends. The first media end may be engaged by a first end piece (e.g., an end cap). The second media end may be engaged by a second end piece (e.g., an end cap). Thus, the safety filter media may extend between opposing end caps (e.g., end pieces). The safety filter media may be pleated media, although alternatives are possible. The safety filter media may be configured in a cylindrical pattern, although alternatives are possible. For example, the safety filter media may be somewhat conical in its extent between the opposing ends. The safety filter media may also be configured with a non-circular inner and / or outer periphery, such as an oval, elliptical, or other cross-sectional configuration. In some embodiments, the safety filter media is disposed around a central plenum to achieve these various configurations.

[0020] In preferred embodiments, for example in cylindrical pleated safety filter elements, the flow generally turns substantially as it enters and exits the safety filter media. That is, the flow enters the cylindrical safety filter element through a cylindrical side and then turns to exit through the open end of the safety filter media (in a forward flow system). In a typical reverse flow system, the flow enters the cylindrical pleated safety filter element through the open end of the safety filter media and then turns to exit through the side of the cylindrical filter media.

[0021] The safety filter media can be provided as any type of media, such as those commonly used in secondary filter elements. Exemplary media include pleated and non-pleated media (such as nonwoven media) and multi-layer laminates.

[0022] In a preferred embodiment, the safety filter media has the shape of a hollow cylinder or a hollow truncated cone. In a preferred embodiment, the safety filter media laterally surrounds a safety filter media interior space, while the safety filter media interior space is bounded at the top by a safety filter element end cap and / or bounded at the bottom by a safety filter element end cap. In a preferred embodiment, the safety filter media interior space is bounded at the top by a closed safety filter element end cap and bounded at the bottom by a safety filter element end cap having an outlet opening.

[0023] A main filter element used as part of a filter system and / or filter assembly includes a main filter media. In a preferred embodiment, the main filter media extends between first and second opposing media ends. The first media end may be engaged by a first end piece (e.g., an end cap). The second media end may be engaged by a second end piece (e.g., an end cap). Thus, the main filter media may extend between opposing end caps (e.g., end pieces). The main filter media may be a pleated media, although alternatives are possible. The main filter media may be configured in a cylindrical pattern, although alternatives are possible. For example, the main filter media may be somewhat conical in its extent between the opposing ends. The main filter media may also be configured with non-circular inner and / or outer peripheries, such as oval, elliptical, or other cross-sectional configurations. In some embodiments, the main filter media is arranged around a central plenum to achieve these various configurations.

[0024] In preferred embodiments, for example in a cylindrical pleated main filter element, the flow typically undergoes a substantial change of direction as it enters and exits the main filter media, i.e., the flow enters the cylindrical main filter element through a cylindrical side and then turns to exit through the open end of the main filter media (in a forward flow system). In a typical reverse flow system, the flow enters the cylindrical pleated main filter element through an open end of the main filter media and then turns to exit through the side of the cylindrical filter media.

[0025] The main filter media can be provided as any type of media, such as those commonly used in secondary filter elements. Exemplary media include pleated and non-pleated media (such as nonwoven media) and multi-layer laminates.

[0026] In a preferred embodiment, the safety filter media and the main filter media are made from the same material. In the alternative, the safety filter media and the main filter media are made from different materials. The differences in materials may be as follows:

[0027] Differences in chemical composition, while other parameters like density or porosity or number of layers can be the same or different.

[0028] Differences in the number of layers, while other parameters like density or porosity or chemical composition can be the same or different.

[0029] Differences in density, while other parameters such as the number of layers or the porosity or chemical composition can be the same or different.

[0030] Differences in porosity, while other parameters such as density or number of layers or chemical composition can be the same or different.

[0031] In a preferred embodiment, the safety filter media comprises fibers and the main filter media comprises fibers, and the difference in chemical composition is achieved by selecting different fibers for the safety filter media and the main filter media.

[0032] In a preferred embodiment, the safety filter media comprises pleated filter media and the main filter media comprises pleated filter media, whereby the material differences are obtained by differences in pleat depth and / or pleat count and / or pleat spacers, either alone or possibly in combination with other differences.

[0033] In a preferred embodiment, the main filter media has the shape of a hollow cylinder or a hollow truncated cone.

[0034] The safety filter element according to the present invention has a safety filter element circumferential support structure. The term "circumferential support structure" is understood to refer to a support structure that is a closed loop of any shape or form. One can start at any point on the circumferential support structure and trace a path along the circumferential support structure and then return to the starting point. In a preferred embodiment, one can start at any point on the safety filter element circumferential support structure and trace a path along the safety filter element circumferential support structure that cycles around the axis of the safety filter element, the axis dissects the safety filter element circumferential support structure and then returns to the starting point. Preferably, the axis is the longitudinal axis of the safety filter element.

[0035] In a preferred embodiment, the safety filter element circumferential support structure is a safety filter element circumferential surface. The term "circumferential surface" is understood to refer to a surface that is a closed loop of any shape or form. One can start at any point on the circumferential surface and follow a path along the circumferential surface and then return to the starting point. In a preferred embodiment, one can start at any point on the safety filter element circumferential surface and follow a path along the safety filter element circumferential surface that cycles around the axis of the safety filter element, where the axis does not cut through the safety filter element circumferential surface and then return to the starting point. Preferably, the axis is the longitudinal axis of the safety filter element.

[0036] The present description describes a safety filter element circumferential support structure, since embodiments are feasible in which the sealing component, which is disposed on and extends along the safety filter element circumferential support structure, cannot be lifted from the safety filter element circumferential support structure to reveal a surface. This applies to embodiments in which the sealing component is glued or welded onto the safety filter element circumferential support structure. However, this also applies to embodiments in which the safety filter element circumferential support structure and the sealing component are manufactured by co-injection, in particular by 2k injection molding (two shot injection). In such an embodiment, the safety filter element circumferential support structure is provided by injecting a first material into a mold, while the sealing component is provided by injecting a second material into the mold. In such an embodiment, the safety filter element circumferential support structure and the sealing component can be identified by cutting through the end cap. The material transition between the material forming the safety filter element circumferential support structure and the material forming the sealing component becomes visible in cross section. Typically, the materials used for the safety filter element circumferential support structure have a higher shore strength as compared to the materials used for the sealing components.

[0037] In order to better describe the possible geometries of the safety filter element circumferential surface according to one aspect of the present invention, the safety filter element circumferential surface is described as including several surface sections. This method of describing the safety filter element circumferential surface is merely used as a means of describing the possible shapes of the safety filter element circumferential surface. The reference to surface sections does not necessarily mean that the individual surface sections are distinct elements of the safety filter element circumferential surface. It is not necessary that the surface sections terminate in an edge, latch, ridge, crest or any other clearly distinguishable object that distinguishes a first surface section from a second adjacent surface section, although such a design is feasible. The present invention also has embodiments in which the safety filter element circumferential surface is described as including several multiple surface sections, but these surface sections are not distinguishable from each other, for example, when the safety filter element circumferential surface has the shape of the outer surface of a cylinder, which can be said to be composed of multiple, possibly even innumerable, surface sections that are not distinguishable from each other. The same rationale applies for a safety filter element circumferential surface having the shape of an outwardly facing surface of a frusto-cone, which is also a possible embodiment for a safety filter element circumferential surface according to the present invention.

[0038] However, in other embodiments of the safety filter element circumferential surface, at least one surface section is clearly distinguishable from other surface sections because the particular surface section terminates in a ridge with adjacent surface sections terminating in the same ridge. Alternatively, the surface sections may be distinguishable because a terminal line, understood to be a line describing one end of the surface section, has a discrete change in its shape, e.g., a kink.

[0039] The shape of the safety filter element circumferential surface is preferably selected taking into account the sealing component provided according to the invention to extend along the safety filter element circumferential surface. In particular, the safety filter element circumferential surface can be selected in its shape to cooperate with a sealing component intended to function primarily as a radial seal. If the sealing component is selected to function primarily as an axial seal, the shape of the safety filter element circumferential surface can be appropriately adapted.

[0040] According to the invention, at least one of the surface sections is arranged such that a normal vector to the surface section is oriented along or parallel to an axis or is arranged to point to the outside of the safety filter element. A normal vector is a vector that starts at the surface section and is oriented perpendicular to the surface section. A normal vector that points to the outside of the safety filter element is considered to be a vector that starts at the surface of the surface section and extends to the outside of the safety filter element and does not extend through the filter element to the opposite side of the filter element.

[0041] In a preferred embodiment, the majority of the surface sections that make up the safety element circumferential surface are arranged such that the normal vector to the respective surface section is oriented along or parallel to an axis or points to the outside of the safety filter element. In a preferred embodiment, the vast majority (greater than 75%) of the surface sections that make up the safety element circumferential surface are arranged such that the normal vector to the respective surface section is oriented along or parallel to an axis or points to the outside of the safety filter element.

[0042] In a preferred embodiment, the safety filter element circumferential surface is provided by a circular ring-shaped surface arranged in a plane perpendicular to the longitudinal axis of the safety filter element. The circular ring-shaped safety filter element circumferential surface is preferably arranged as a ring around the longitudinal axis. If a sealing component is provided to extend along such a safety filter element circumferential surface, the sealing component is preferably used to act as an axial seal. Such a circular circumferential ring-shaped safety filter element circumferential surface can be provided, for example, by a ring-shaped wall or rim that projects radially above the other parts of the safety filter element. Such a design provides an additional advantage, because the opposite side of such a circumferential wall or rim, which is also circular and ring-shaped and points in the opposite direction, can be used to provide a housing sealing component to extend along this surface, which in this design can also function as an axial seal. In such a design, all surface sections of the safety filter element circumferential surface are arranged such that the normal vector to each surface section is oriented parallel to the axis of the safety filter element.

[0043] As a modification of the above-mentioned design, the radially extending circumferential wall or rim can be adapted to have a surface section that is offset from the remainder of the wall / rim in the direction of the axis of the safety filter element. In such a design, some surface sections constituting the safety filter element circumferential surface are arranged in the same plane, while further surface sections are arranged, for example, in different but parallel planes, while a first angled surface section connects some surface sections with an offset surface section on one side, while a second angled surface section connects some surface sections with an offset surface section on the other side. Thus, the angled surface sections look like a ramp, from a plane where some surface sections rise to and fall from the offset surface section on one side, back to the plane where some surface sections are arranged. In such a design, some surface sections are respectively arranged such that the normal vector to each surface section is oriented parallel to the axis. A surface section that is offset from several surface sections is also a surface section that is oriented such that the normal vector to this offset surface section is oriented parallel to the axis. Only angularly oriented surface sections are not oriented such that their respective normal vectors are oriented parallel to the axis. Their normal vectors are oriented at an angle to a plane that contains the axis.

[0044] In the above design, if the offset surface section faces are considered to be peaks and several such peaks are provided as part of the safety filter element circumferential surface, the safety filter element circumferential surface can be described as wavy between the peaks and valleys, with the angularly oriented surface sections disposed between the peaks and valleys. The maximum peak-valley-structure is a wave-like structure, where each surface section on the peak with a normal vector parallel to the axis is infinitesimal, and the surface sections that form valleys and have a normal vector parallel to the axis are also infinitesimal.

[0045] In a preferred embodiment, the peak-valley or wave design can be symmetrical in the sense that the wave peaks / tips are distributed equidistantly around the safety filter element circumferential surface. In a preferred embodiment, the safety filter element circumferential surface forms a contour shape with single fold rotational symmetry. In such a design, for example, only one hill (peak) is provided, or if multiple hills (peaks) are provided, they are distributed unequal distances around the safety filter element circumferential surface.

[0046] In the alternative, the safety filter element circumferential surface is designed to work with a sealing component that extends along the safety filter element circumferential surface and is intended to be used primarily as a radial seal. In such a design, at least one surface section of the safety filter element circumferential surface is arranged such that a normal vector to the surface section is oriented to point to the outside of the safety filter element, preferably pointing radially outward from the safety filter element. In a preferred embodiment, the safety filter element circumferential surface is made up of surface sections each forming a part of the outer surface of a cylinder. In the simplest way, all surface sections are arranged at the same height of the cylinder, making the safety filter element circumferential surface a ring-shaped surface on the outside of the cylinder.

[0047] As a modification of the above-mentioned design, the safety filter element circumferential surface, which is a ring-shaped surface on the outside of the cylinder, can be adapted to have a surface section that is offset from the rest of the surface sections in the direction of the axis of the safety filter element. In such a design, some surface sections constituting the safety filter element circumferential surface are arranged to form a part of a ring-shaped surface on the outside of the cylinder, while further surface sections are arranged to form a part of a different ring-shaped surface on the outside of the cylinder, for example, while a first angled surface section connects some surface sections with one offset surface section on one side, while a second angled surface section connects some surface sections with one offset surface section on the other side. Thus, the angled surface sections look like a ramp, going from a ring that goes up to the offset surface section on one side and down from the offset surface section, back to the ring on which the several surface sections are arranged. In such a design, all normal vectors to the respective surface sections are oriented to point towards the outside of the safety filter element.

[0048] In the above design, if the offset surface sections are considered to be peaks, and several such peaks are provided as part of the safety filter element circumferential surface, then the safety filter element circumferential surface can be described as undulating between the peaks and valleys, with the angularly oriented surface sections disposed between the peaks and valleys. The maximum peak-valley structure is a undulating structure, with each surface section above the peaks being infinitesimal, and the surface sections forming the valleys also being infinitesimal.

[0049] In a preferred embodiment, the peak-valley or wave design can be symmetrical in the sense that the wave peaks / tips are distributed equidistantly around the safety filter element circumferential surface. In a preferred embodiment, the safety filter element circumferential surface forms a contour shape with one-fold rotational symmetry. In such a design, for example, only one hill (peak) is provided, or, if multiple hills (peaks) are provided, they are distributed unequal distances around the safety filter element circumferential surface.

[0050] As a modification of the above-mentioned design, the safety filter element circumferential surface, which is a ring-shaped surface on the outside of the cylinder, can be adapted to have a surface section that is offset from the remainder of the surface section in the radial direction. In such a design, some surface sections that make up the safety filter element circumferential surface are arranged to form a part of the ring-shaped surface on the outside of the cylinder, while further surface sections are arranged, for example, in bumps or protrusions that protrude radially from the ring-shaped surface on the outside of the cylinder, or further surface sections are arranged more radially inward, for example, in recesses or indentations. A first angled surface section can connect some surface sections with one offset surface section, while a second angled surface section can connect some surface sections with one offset surface section on the other side. Thus, the angled surface sections appear as a ramp leading from a ring in which some surface sections are disposed radially outward (or inward depending on the arrangement of the offset surface sections) to an offset surface section on one side, and then from the offset surface section radially inward (or outward) back to the ring in which some surface sections are disposed. In such a design, all normal vectors to each surface section are oriented to point to the outside of the safety filter element.

[0051] In the above mentioned designs, the offset surface sections are considered as peaks, and if several such peaks are provided as part of a certain safety filter element circumferential surface, the safety filter element circumferential surface can be described as undulating between peaks and valleys, with angularly oriented surface segments disposed between the peaks and valleys. The maximum peak-valley structure is a wavy structure, and each surface section on the peaks is infinitesimal, and the surface sections forming the valleys are also infinitesimal.

[0052] In a preferred embodiment, the peak-valley or wave design can be symmetrical in the sense that the wave peaks / tips are distributed equidistantly around the safety filter element circumferential surface. In a preferred embodiment, the safety filter element circumferential surface forms a contour shape with one-fold rotational symmetry. In such a design, for example, only one hill (peak) is provided, or, if several hills (peaks) are provided, they are distributed unequal distances around the safety filter element circumferential surface.

[0053] In a preferred embodiment, several surface sections making up the safety filter element circumferential surface are disposed in the same plane, such that the safety filter element circumferential surface is disposed in said plane.

[0054] In a preferred embodiment, the several surface sections making up the safety filter element circumferential surface are designed to together form the outer surface of a cone, such that the safety filter element circumferential surface is designed to form the outer surface of a cone.

[0055] In a preferred embodiment, the several surface sections that make up the safety filter element circumferential surface are designed to together form the outer surface of a cylinder, such that the safety filter element circumferential surface is designed to form the outer surface of a cylinder.

[0056] In a preferred embodiment, the several surface sections making up the safety filter element circumferential surface are designed to together form the outer surface of a cylinder, having a triangular or quadratic or pentagonal, hexagonal, heptagonal, octagonal, polygonal, preferably polygonal but symmetrical cross-section cylinder.

[0057] In a preferred embodiment, a first surface section of the several surface sections making up the safety filter element circumferential surface is arranged in a plane, such that at least a portion of the safety filter element circumferential surface made up by the first surface section is arranged in said plane, and a second surface section of the several surface sections making up the safety filter element circumferential surface is arranged in a different plane.

[0058] In a preferred embodiment, a first surface section of the several surface sections making up the safety filter element circumferential surface is designed to form a section of the outer surface of a cone, such that at least a portion of the safety filter element circumferential surface made up of the first surface section is designed to form a section of the outer surface of a cone, and a second surface section of the several surface sections making up the safety filter element circumferential surface is designed to form a section of the outer surface of a different cone.

[0059] In a preferred embodiment, a first surface section of the several surface sections making up the safety filter element circumferential surface is designed to form a section of the outer surface of a cylinder, such that at least a portion of the safety filter element circumferential surface made up of the first surface section is designed to form a section of the outer surface of a cylinder, and a second surface section of the several surface sections making up the safety filter element circumferential surface is designed to form a section of the outer surface of a different cylinder.

[0060] For surface sections that are curved rather than flat, each surface section is considered to be positioned such that the normal vector points outside the safety filter element, in particular is oriented to point radially outward from the safety filter element, if the normal vector to at least one infinitesimal subsection of such surface section is oriented to point outside the safety filter element.

[0061] The safety filter element circumferential surface can also be designed such that several surface sections, preferably a majority of the surface sections, preferably all surface sections constituting the safety filter element circumferential surface, are arranged in the same plane.The safety filter element circumferential surface can also be designed such that several surface sections, preferably a majority of the surface sections, preferably all surface sections constituting the safety filter element circumferential surface, are arranged on the outer surface of a cylinder, preferably at the same height.The safety filter element circumferential surface can also be designed such that several surface sections, preferably a majority of the surface sections, preferably all surface sections constituting the safety filter element circumferential surface, are arranged on a cone.

[0062] According to one embodiment of the invention, at least one sealing component extends along the safety filter element circumferential surface, said sealing component being a circumferential object, which is understood to refer to an object that is a closed loop, whereby one can start at any point on said object and trace a path along said object back to the starting point, in particular a path along said object that circulates around the axis of the safety filter element, which axis returns to the start without cutting through the object, which axis is preferably the longitudinal axis of the safety filter component.

[0063] The sealing component can be provided by a material that is attached to the safety filter element circumferential surface. Thus, the sealing component does not have to be a stand-alone or independent object. The sealing component can be, for example, an O-ring and thus is a stand-alone independent object, but a sealing material that is provided by a sealing material that is attached to the safety filter element circumferential surface, for example, a galvanized sealing material that is galvanized to the safety filter element circumferential surface, is not considered to be a stand-alone independent object.

[0064] The sealing component can be a PU (polyurethane) seal, which is preferably compressed in its sealing state. The PU seal can be overmolded onto the structure, e.g. the end cap. The overmolding can be done by potting. Also, a TPE (thermoplastic elastomer) seal, Thixo seal (silicone) can be used. Also, a seal using FERMAPOR K31-A-9308-5-VP5 / K31-B-4 material from Sonderhof / Henkel can be used.

[0065] The sealing component can be part of a larger object: in a preferred embodiment the sealing component is part of a sleeve-like element, where certain parts of the sleeve constitute the sealing component, while in a preferred embodiment other parts may constitute a further sealing component, e.g. a housing sealing component.

[0066] In a preferred embodiment, the safety filter element has a first safety filter element circumferential surface as described above and a second safety filter element circumferential surface, whereby the first sealing component extends along the first safety filter element circumferential surface and the second sealing component extends along the second safety filter element circumferential surface. The first sealing component and the second sealing component can be parts of the same stand-alone, independent object, such as a sleeve. In such a design, the first sealing component can be used as an axial seal while the second sealing component can be used as a radial seal.

[0067] The sealing component may be attached to the safety filter element circumferential surface by being galvanized to the safety filter element circumferential surface, by being glued to the safety filter element circumferential surface, or by being welded to the safety filter element circumferential surface. The sealing component, especially if it is a stand-alone elastic object, may hold itself to the safety filter element circumferential surface by its resilience. If the sealing component is provided by, for example, an O-ring, the resilience of the O-ring may hold the O-ring to the safety filter element circumferential surface.

[0068] The safety filter element circumferential surface may include a groove, particularly a circumferential groove, and the sealing component, particularly if a stand-alone, separate object, may be partially disposed inside the groove, for example an O-ring may be partially disposed inside the groove.

[0069] In a preferred embodiment, the sealing component is a lip seal. Preferably, the lip seal comprises a thermoplastic elastomer (TPE) or another flexible material suitable for providing a sealing effect. In general, the sealing direction of the lip seal on the filter element corresponds to a major component direction selected from the radial and axial components of the lip.

[0070] Preferably, the lip seal comprises an elongated base having a front and a rear surface, and an elongated lip structure or lip extending from the front surface of said base. Preferably, the lip seal comprises a T-shaped cross section. The base is preferably essentially planar and forms an angle with the lip. The angle is preferably in the range of 30° to 90°. The angle is more preferably close to 90°, for example in the range of 75° to 89°. According to a preferred embodiment, the lip forms an oblique angle with respect to the axis of the safety filter element. This "symmetry breaking" bias of the lip seal causes the lip seal to move in the correct direction during use so as to optimally withstand the air pressure differentials to which the lip seal is typically exposed. According to a preferred embodiment in which the support structure comprises a smooth, continuous band surface following the seal, the base of the lip seal is preferably attached to the band surface. Preferably, it is in direct or indirect contact with said band surface. The base of the lip seal is preferably substantially parallel or parallel to the smooth, continuous band surface following it. In such an embodiment, the angle between the lip and the band surface preferably corresponds to the angle between the lip and the base.

[0071] According to a preferred embodiment, the angle between the lip seal and the base is constant along the closed loop trajectory. According to an alternative embodiment, the angle between the lip seal and the base is not constant along the closed loop trajectory.

[0072] In a preferred embodiment, in addition to one sealing component, a housing sealing component is provided on the safety filter element. In a preferred embodiment, the safety filter element has a housing sealing component circumferential surface.

[0073] In a preferred embodiment, the housing sealing component is disposed on and extends along the housing sealing component circumferential support structure. The term "circumferential support structure" is understood to refer to a support structure that is a closed loop of any shape or form. One can start at any point on the circumferential support structure and follow a path along the circumferential support structure and then return to the starting point. In a preferred embodiment, one can start at any point on the safety filter element circumferential support structure and follow a path along the safety filter element circumferential support structure that cycles around the axis of the safety filter element, where the axis does not cut through the safety filter element circumferential support structure and then return to the starting point. Preferably, the axis is the longitudinal axis of the safety filter element.

[0074] In a preferred embodiment, the housing sealing element circumferential support structure is a housing sealing element circumferential surface. The term "circumferential surface" is understood to refer to a surface that is a closed loop of any shape or form. One can start at any point on the circumferential surface and follow a path along the circumferential surface and then return to the starting point. In a preferred embodiment, one can start at any point on the safety filter element circumferential surface and follow a path along the safety filter element circumferential surface that cycles around an axis of the safety filter element, where the axis does not cut through the safety filter element circumferential surface and then return to the starting point. Preferably, the axis is the longitudinal axis of the safety filter element.

[0075] This description describes the housing sealing element circumferential support structure, since embodiments are feasible in which the housing sealing component, which is arranged on and extends along the housing sealing element circumferential support structure, cannot lift the housing sealing element circumferential support structure to expose a surface. This applies to embodiments in which the housing sealing component is glued or welded to the housing sealing element circumferential support structure. However, this also applies to embodiments in which the housing sealing element circumferential support structure and the housing sealing component are manufactured by co-injection, in particular by 2k injection molding (two-shot injection). In such an embodiment, the housing sealing element circumferential support structure is provided by injecting a first material into the mold, while the housing sealing component is provided by injecting a second material into the mold. In such an embodiment, the housing sealing element circumferential support structure and the housing sealing component can be identified by cutting through the end cap. The material transition between the material forming the housing sealing element circumferential support structure and the material forming the sealing component becomes visible in cross section. Typically, the materials used for the housing sealing element circumferential support structures have a higher shore strength as compared to the materials used for the housing sealing components.

[0076] In order to better describe the possible geometries of the housing sealing element circumferential surface according to one aspect of the invention, the housing sealing element circumferential surface is described as including several surface sections. This method of describing the housing sealing element circumferential surface is merely used as a means of describing the possible shapes of the housing sealing element circumferential surface. The reference to surface sections does not necessarily mean that the individual surface sections are distinct elements of the housing sealing element circumferential surface. It is not necessary that the surface sections terminate in an edge, latch, ridge, crest or any other clearly distinguishable object that distinguishes a first surface section from a second adjacent surface section, although such designs are feasible. Although the invention is described as the housing sealing element circumferential surface includes several surface sections, it also has embodiments in which these surface sections are not distinguishable from one another, for example when the housing sealing element circumferential surface has the shape of the outer surface of a cylinder, which can be said to be composed of multiple, possibly even innumerable, surface sections that are not distinguishable from one another. The same rationale also applies to a housing sealing element circumferential surface having the shape of the outwardly facing surface of a truncated cone, which is also a possible embodiment for the housing sealing element circumferential surface according to the invention.

[0077] However, in other embodiments of the housing sealing element circumferential surface, at least one surface section is clearly distinguishable from the other surface sections. This may be the case because a particular surface section terminates in a ridge and an adjacent surface section terminates in the same ridge. Alternatively, the surface sections may be distinguishable because a termination line, understood to be a line describing one end of the surface section, has a discontinuous change in its shape, e.g., a kink.

[0078] The shape of the housing sealing element circumferential surface is preferably selected with a view to the housing sealing element provided according to the invention to extend along the housing sealing element circumferential surface. In particular, the shape of the housing sealing element circumferential surface can be selected to cooperate with a housing sealing component intended to function primarily as a radial seal. If a housing sealing component is selected to function primarily as an axial seal, the shape of the housing sealing element circumferential surface can be appropriately adapted.

[0079] According to the invention, at least one of the surface sections is arranged such that a normal vector to the surface section is oriented along or parallel to an axis or is arranged to point to the outside of the safety filter element. A normal vector is a vector that starts on the surface section and is oriented perpendicular to the surface section. A normal vector that points to the outside of the safety filter element is considered to be a vector that starts from the surface of the surface section and extends to the outside of the safety filter element and does not extend through the filter element to the opposite side of the filter element.

[0080] In a preferred embodiment, the majority of the surface sections that make up the safety element circumferential surface are arranged such that the normal vector to the respective surface section is oriented along or parallel to an axis or points to the outside of the safety filter element. In a preferred embodiment, the vast majority (greater than 75%) of the surface sections that make up the safety element circumferential surface are arranged such that the normal vector to the respective surface section is oriented along or parallel to an axis or points to the outside of the safety filter element.

[0081] In a preferred embodiment, the housing sealing element circumferential surface is provided by a circular ring-shaped surface arranged in a plane perpendicular to the axis of the safety filter element. The circular ring-shaped housing sealing element circumferential surface is preferably arranged as a ring around the axis. If a housing sealing element is provided to extend along the housing sealing element circumferential surface, the housing sealing element is preferably used to act as an axial seal. Such a circular circumferential ring-shaped housing sealing element circumferential surface can be provided, for example, by a ring-shaped wall or rim that projects radially above the other parts of the safety filter element. Such a design provides an additional advantage, since the opposite side of such a circumferential wall or rim, which is also circular and ring-shaped and points in the opposite direction, can be used to provide a sealing component extending along this surface, which in this design can also function as an axial seal. In such a design, all surface sections of the housing sealing element circumferential surface are arranged such that the normal vector to the respective surface section is oriented parallel to the axis of the safety filter element.

[0082] As a modification of the above-mentioned design, the radially extending circumferential wall or rim can be adapted to have a surface section that is offset from the remainder of the wall / rim in the direction of the axis of the safety filter element. In such a design, some surface sections constituting the housing sealing element circumferential surface are arranged in the same plane, while further surface sections are arranged, for example, in different but parallel planes, while a first angled surface section connects some surface sections with an offset surface section on one side, while a second angled surface section connects some surface sections with one offset surface section on the other side. Thus, the angled surface sections look like a ramp that goes up from the plane in which the several surface sections are arranged to the offset surface section on one side and down from the offset surface section back to the plane in which the several surface sections are arranged. In such a design, the several surface sections are arranged such that the normal vector to each surface section is oriented parallel to the axis. A surface section that is offset from several surface sections is also a surface section that is oriented such that the normal vector to this offset surface section is oriented parallel to the axis. Only angularly oriented surface sections are not oriented such that their respective normal vectors are oriented parallel to the axis. Their normal vectors are oriented at an angle to a plane that contains the axis.

[0083] In the above mentioned design, if the offset surface sections are considered as peaks and several such peaks are provided as part of the housing sealing element circumferential surface, the housing sealing element circumferential surface can be described as wavy between the peaks and valleys, with the angularly oriented surface sections being located between the peaks and valleys. The maximum peak-valley structure is a wave-like structure, where each surface section on the peaks with a normal vector parallel to the axis is infinitesimal, and the surface sections that form valleys and also have a normal vector parallel to the axis are also infinitesimal.

[0084] In a preferred embodiment, the peak-valley or wave design can be symmetrical in the sense that the wave peaks / tips are distributed equidistantly around the housing sealing element circumferential surface. In a preferred embodiment, the housing sealing element circumferential surface forms a contour shape with one-fold rotational symmetry. In such a design, for example, only one hill (peak) is provided, or if multiple hills (peaks) are provided, they are distributed unequal distances around the housing sealing element circumferential surface.

[0085] Alternatively, the housing sealing element circumferential surface is designed to work with a housing sealing element that extends along the housing sealing element circumferential surface and is intended to be used primarily as a radial seal. In such a design, at least one surface section of the housing sealing element circumferential surface is arranged such that a normal vector to the surface section is oriented to point to the outside of the safety filter element, preferably pointing radially outward from the safety filter element. In a preferred embodiment, the housing sealing element circumferential surface is made up of surface sections each forming a portion of the outer surface of a cylinder. In the simplest way, all surface sections are arranged at the same height of the cylinder, making the housing sealing element circumferential surface a ring-shaped surface on the outside of the cylinder.

[0086] As a modification of the above-mentioned design, the housing sealing element circumferential surface, which is a ring-shaped surface on the outside of the cylinder, can be adapted to have a surface section offset from the rest of the surface section in the direction of the axis of the safety filter element. In such a design, some surface sections constituting the housing sealing element circumferential surface are arranged to form a portion of a ring-shaped surface on the outside of the cylinder, while further surface sections are arranged to form a portion of a different ring-shaped surface on the outside of the cylinder, for example, while a first angled surface section connects some surface sections with one offset surface section on one side, while a second angled surface section connects some surface sections with one offset surface section on the other side. Thus, the angled surface sections look like a ramp that goes up from the ring on which the several surface sections are arranged to the offset surface section on one side and back to the ring on which the several surface sections are arranged from the offset surface section. In such a design, all normal vectors to the respective surface sections are oriented to point towards the outside of the safety filter element.

[0087] In the above design, if the offset surface sections are considered to be peaks, and several such peaks are provided as part of the housing sealing element circumferential surface, then the housing sealing element circumferential surface is described as wavy between the peaks and valleys, with the angularly oriented surfaces disposed between the peaks and valleys. The maximum peak-valley structure is a wavy structure, and each surface section above the peaks is infinitesimal, and the surface sections forming the valleys are also infinitesimal.

[0088] In a preferred embodiment, the peak-valley or wave design can be symmetrical in the sense that the wave peaks / tips are distributed equidistantly around the housing sealing element circumferential surface. In a preferred embodiment, the housing sealing element circumferential surface forms a contour shape with one-fold rotational symmetry. In such a design, for example, only one hill (peak) is provided, or if multiple hills (peaks) are provided, they are distributed unequal distances around the housing sealing element circumferential surface.

[0089] In a preferred embodiment, several surface sections making up the housing closure element circumferential surface are arranged in the same plane, such that the housing closure element circumferential surface is arranged in said plane.

[0090] In a preferred embodiment, the several surface sections making up the housing sealing element circumferential surface are designed to together form the outer surface of a cone, such that the housing sealing element circumferential surface is designed to form the outer surface of a cone.

[0091] In a preferred embodiment, the several surface sections that make up the housing sealing element circumferential surface are designed to together form the outer surface of a cylinder, such that the housing sealing element circumferential surface is designed to form the outer surface of a cylinder.

[0092] In a preferred embodiment, a first surface section belonging to the several surface sections making up the housing sealing element circumferential surface is arranged in a plane, such that at least a portion of the housing sealing element circumferential surface made up of the first surface section is arranged in said plane, and a second surface section belonging to the several surface sections making up the housing sealing element circumferential surface is arranged in a different plane.

[0093] In a preferred embodiment, a first surface section belonging to the several surface sections making up the housing sealing element circumferential surface is designed to form a section of the outer surface of a cone, such that at least a portion of the housing sealing element circumferential surface made up of the first surface section forms a section of the outer surface of a cone, and a second surface section belonging to the several surface sections making up the housing sealing element circumferential surface forms a section of the outer surface of a different cone.

[0094] In a preferred embodiment, a first surface section belonging to the several surface sections making up the housing sealing element circumferential surface is designed to form a section of the outer surface of a cylinder, such that at least a part of the housing sealing element circumferential surface made up of the first surface section is designed to form a section of the outer surface of a cylinder, and a second surface section belonging to the several surface sections making up the housing sealing element circumferential surface is designed to form a section of the outer surface of a different cylinder.

[0095] For non-flat curved surface sections, each surface section is considered to have a normal vector oriented to point outside the safety filter element, in particular pointing radially outward from the safety filter element, if the normal vector to at least one infinitesimal subsection of such surface section is oriented to point outside the safety filter element.

[0096] The housing sealing element circumferential surface can also be designed such that several surface sections, preferably a majority of the surface sections, preferably all surface sections constituting the housing sealing element circumferential surface, are arranged in the same plane. The housing sealing element circumferential surface can also be designed such that several surface sections, preferably a majority of the surface sections, preferably all surface sections constituting the housing sealing element circumferential surface, are arranged on the outer surface of a cylinder, preferably at the same height. The housing sealing element circumferential surface can also be designed such that several surface sections, preferably a majority of the surface sections, preferably all surface sections constituting the housing sealing element circumferential surface, are arranged on a cone.

[0097] According to one embodiment of the invention, at least one housing sealing component extends along the housing sealing element circumferential surface, said housing sealing component being a circumferential object, which is understood to refer to an object that is a closed loop, whereby one can start at any point on said object and trace a path along said object and then return to the starting point, in particular trace a path along said object that circulates around the axis of the safety filter element, the axis not cutting through the object and then returning to the starting point, the axis being preferably the longitudinal axis of the safety filter component.

[0098] The housing sealing component can be provided by a material attached to the housing sealing element circumferential surface. Thus, the housing sealing component does not have to be a stand-alone or independent object. The housing sealing component can be, for example, an O-ring and is therefore a stand-alone independent object, but a housing sealing component provided by a sealing material attached to the housing sealing element circumferential surface, for example, a sealing material galvanized onto the housing sealing element circumferential surface, is not considered to be a stand-alone independent object.

[0099] The housing sealing component can preferably be a PU (polyurethane) seal, which is compressed in its sealing state. The PU seal can be overmolded onto the structure, e.g., the end cap. The overmolding can be done by potting. A TPE (thermoplastic elastomer) seal, Thixo seal (silicone), could also be used. A seal using FERMAPOR K31-A-9308-5-VP5 / K31-B-4 material from Sonderhof / Henkel could also be used.

[0100] The housing sealing component can be part of a larger object: in a preferred embodiment the housing sealing component is part of a sleeve-like element, in which case certain parts of the sleeve constitute the housing sealing component, while in a preferred embodiment other parts can constitute further sealing components, for example a sealing component sealing to a main filter component.

[0101] In a preferred embodiment, the safety filter element has a first housing sealing element circumferential surface as described above and a second housing sealing element circumferential surface, whereby the first housing sealing component extends along the first housing sealing element circumferential surface and the second housing sealing component extends along the second housing sealing element circumferential surface. The first housing sealing component and the second housing sealing component can be parts of the same stand-alone, independent object, e.g., a sleeve. In such a design, the first housing sealing component can be used as an axial seal while the second housing sealing component can be used as a radial seal.

[0102] In a preferred embodiment, the safety filter element end cap has a circular rim that circumscribes the longitudinal axis of the safety filter element, thereby The safety filter element circumferential support structure is provided above the circular rim or on an upwardly facing surface of the rim. l The housing sealing element circumferential support structure is provided below the circular rim or on the downwardly facing surface of the rim.

[0103] In a preferred embodiment, the safety filter element has a safety filter element end cap disposed at one end of the safety filter media, and the safety filter element circumferential surface is preferably the above-mentioned safety filter element circumferential surface with several surface sections, but possibly also a safety filter element circumferential surface of a different design disposed on the safety filter element end cap. In a preferred embodiment, the safety filter media has a safety filter media interior space, and the safety filter element end cap has an outlet opening leading to the safety filter media interior space. In a preferred embodiment, the safety filter element has only one outlet opening leading to the safety filter media interior space.

[0104] In a preferred embodiment, the safety filter media has a safety filter media interior space whereby a safety filter element end cap is provided having an outlet opening that communicates with the safety filter media interior space. In a preferred embodiment, the safety filter element end cap having the outlet opening is provided on one side of the safety filter media and a further safety filter element end cap having no opening and closing the safety filter media at one end is provided on the opposite end.

[0105] In an embodiment, in addition to one sealing component, a housing sealing component is provided, and a particularly preferred embodiment also provides a housing sealing component to be disposed on the safety filter element end cap as well.

[0106] In a preferred embodiment, the safety filter element circumferential surface forms a profile shape with one-fold rotational symmetry. A closed-loop surface with a profile shape with one-fold rotational symmetry is interpreted as a profile shape that is configured such that when rotating the closed-loop surface, only after a 360° rotation does the profile shape match the initial profile shape at the start of the rotation. In other words, only after a 360° rotation does the profile shape look the same as it did at the start of the rotation. A profile shape with one-fold rotational symmetry does not have an axis of rotational symmetry. In contrast, a profile shape with rotational symmetry has an axis of rotational symmetry such that after a rotation of an angle of 180° or less around the axis of rotational symmetry, the profile shape matches the initial profile shape at the start of the rotation.

[0107] In a preferred embodiment, the safety filter element end caps having the safety filter element circumferential support structures are designed with mirror symmetry about one plane, and in particular only about one plane that contains the longitudinal axis.

[0108] The present invention may also have application in safety filter elements that do not filter debris from a fluid, but rather filter tools that have been dropped into a housing. Instead of having a safety filter media, such designs have a safety cage, whereby the safety cage has a safety cage interior space. Otherwise, the designs may be the same. Thus, in such an embodiment, at least a safety filter element end cap is provided, whereby the safety filter element end cap has an outlet opening that leads to the safety cage interior space. Similarly, the safety filter element end cap has a safety filter element circumferential support structure, whereby the sealing component is disposed on and extends along the safety filter element circumferential support structure, whereby the safety filter element end cap additionally includes a housing sealing component.

[0109] The invention also relates to a filter system.In one embodiment, the filter system according to the invention comprises a safety filter element according to the invention and a main filter element, whereby the main filter element comprises a main filter medium.

[0110] In a preferred embodiment, the main filter media has a main filter media interior space and the safety filter media is at least partially disposed within the main filter media interior space. In a preferred embodiment, more than 50%, preferably more than 75%, preferably more than 90%, preferably more than 95% of the longitudinal extent of the safety filter media is disposed inside the main filter media interior space.

[0111] According to a further aspect of the invention, the filter system according to the invention comprises: a safety filter element, which may be a safety filter element according to the invention, but which may be designed differently in alternative embodiments; a main filter element including a main filter medium, the main filter medium having a main filter medium interior space, and the safety filter medium being at least partially disposed inside the main filter medium interior space; A sealing component is disposed on the safety filter element, the main filter element having a main filter element circumferential surface, whereby the sealing component of the safety filter element is in sealing contact with the main filter element circumferential surface. In a preferred embodiment, more than 50%, preferably more than 75%, preferably more than 90%, preferably more than 95% of the longitudinal extent of the safety filter media is disposed inside the main filter media interior space.

[0112] In a preferred embodiment, the main filter element comprises: a main filter element circumferential surface comprising several surface sections, whereby at least one of the surface sections is arranged such that a normal vector to the surface section is directed along or parallel to the longitudinal axis or towards the inside of the main filter element; l one sealing component of the safety filter element in sealing contact with the main filter element circumferential surface.

[0113] In a preferred embodiment, the main filter element circumferential surface has the same geometric shape as the safety filter element circumferential surface, but is positioned offset relative to the safety filter element circumferential surface to allow for placement of a sealing component between the main filter element circumferential surface and the safety filter element circumferential surface.

[0114] In a preferred embodiment, the main filter element has a main filter element end cap disposed at one end of the main filter media, and the main filter element circumferential surface is disposed in the main filter element end cap. In a preferred embodiment, the main filter media has a main filter media interior space, and the main filter element end cap has an outlet opening that leads to the main filter media interior space. In a preferred embodiment, the main filter element has only one outlet opening that leads to the main filter media interior space.

[0115] In a preferred embodiment, an engagement arrangement is provided between the safety filter element and the main filter element. In a preferred embodiment, the engagement arrangement has a first protrusion, which may be, for example, a radially projecting wing or rib, and a second protrusion, which may also be a radially projecting wing or rib, whereby the first protrusion is smaller than the second protrusion. Furthermore, the engagement arrangement has a first recess and a second recess, whereby the first recess can accommodate the first protrusion but not the second protrusion, and the second recess can accommodate the second protrusion. The engagement arrangement can be configured such that the safety filter element has a first protrusion and a second protrusion, whereby the main filter element has a first recess and a second recess. Alternatively, the engagement arrangement can be provided such that the main filter element has a first protrusion and a second protrusion, whereby the safety filter element has a first recess and a second recess.

[0116] In a preferred embodiment, the safety filter element has a radially extending safety filter element abutment surface and the main filter element has a main filter element abutment surface capable of coming into contact with the safety filter element abutment surface, and abutment of the main filter element abutment surface with the safety filter element abutment surface limits relative movement of the main filter element with respect to the safety filter element along the longitudinal axis.

[0117] The invention also relates to a filter assembly comprising a safety filter element and a housing. In one embodiment of the filter assembly, the safety filter element is a safety filter element according to the invention.

[0118] In one embodiment, a filter assembly according to the invention comprises a housing, a safety filter element, which may be a safety filter element according to the invention but must not be a safety filter element according to the invention, and a main filter element comprising a main filter medium, the main filter medium having a main filter medium inner space, the safety filter medium being at least partially disposed inside the main filter medium inner space, a sealing component being disposed on the safety filter element, the main filter element having a main filter element circumferential surface, whereby the sealing component of the safety filter element is in sealing contact with the main filter element circumferential surface. In a preferred embodiment, more than 50%, preferably more than 75%, preferably more than 90%, preferably more than 95% of the longitudinal extent of the safety filter medium is disposed inside the main filter medium inner space.

[0119] In a preferred embodiment of the filter assembly, in addition to one sealing component, a housing sealing component is provided on the safety filter element. In a preferred embodiment, the housing has a housing sealing circumferential surface that includes several surface sections, whereby at least one of the surface sections is arranged such that a normal vector to the surface section is oriented (1) along the longitudinal axis, or (2) parallel to the longitudinal axis, or (3) toward the inside of the housing, whereby the housing sealing component of the safety filter element is in sealing contact with the housing sealing circumferential surface.

[0120] In a preferred embodiment, the housing sealing circumferential surface on the housing has the same geometric shape as the housing sealing element circumferential surface on the safety filter element, but is positioned offset relative to the housing sealing element circumferential surface to allow for positioning of a housing sealing component between the housing sealing circumferential surface and the housing sealing element circumferential surface.

[0121] In a preferred embodiment, the safety filter element is fixedly connected to the housing or replaceably connected to the housing. In a preferred embodiment, the housing has a housing lid and the safety filter element is fixedly connected to the housing lid or replaceably connected to the housing lid.

[0122] In a preferred embodiment, the housing has a housing interior space, the safety filter element is disposed inside the housing interior space, the housing has a housing outlet, the safety filter media has a safety filter media interior space, and the safety filter media interior space is in direct flow connection with the housing outlet.

[0123] In a preferred embodiment of the filter assembly, a housing engagement arrangement is provided between the safety filter element and the housing, the engagement arrangement having a first protrusion disposed on either the safety filter element or the housing, and the engagement arrangement having a plug-in channel disposed on that portion of the safety filter element or the housing on which the protrusion is not disposed, whereby the protrusion can engage with the plug-in channel to plug-inably connect the safety filter element to the housing. In a preferred embodiment, the first protrusion is disposed on the safety filter element and the plug-in channel is disposed on the housing. In a preferred embodiment, the plug-in channel is disposed on the safety filter element and the first protrusion is disposed on the housing. In a preferred embodiment, the housing engagement arrangement includes more than one protrusion, preferably two, three, or four protrusions. In a preferred embodiment, the housing engagement arrangement has the same number of plug-in channels as protrusions. In a preferred embodiment, the protrusions are equally spaced around the circumference of the safety filter element and the plug-in channel is equally spaced around the circumference of the housing. In a preferred embodiment, the protrusions are equally spaced around the circumference of the housing and the plug-in channels are equally spaced around the circumference of the safety filter element. Equally spacing the protrusions and plug-in channels means that there are as many relative rotational positions for replaceably connecting the safety filter element to the housing as there are protrusions. If it is desired to have only one relative rotational position of the safety filter element with respect to the housing for replaceably connecting the safety filter element to the housing, this can be achieved by offsetting at least one protrusion and corresponding plug-in channel.

[0124] In a preferred embodiment of the filter assembly, a main filter element is provided that includes a main filter media. In a preferred embodiment, the housing has an interior housing space and the main filter element is disposed inside the interior housing space.

[0125] In a preferred embodiment, an unfiltered fluid space is provided between the inwardly facing surface of the housing and the outwardly facing surface of the main filter element, whereby the housing has an inlet in direct flow connection with the unfiltered fluid space.

[0126] The present invention also relates to a method for assembling a filter assembly according to the present invention, the method comprising the steps of: Inserting a safety filter element into the housing; l inserting the safety filter element into the housing, and then inserting the main filter element into the housing.

[0127] In a preferred embodiment, the sealing component and / or the housing sealing component are compressed during the method. Compressing the sealing component and / or the housing sealing component during installation of the safety filter element and / or during installation of the main filter element enhances the action of the seal.

[0128] The present invention also relates to a method for replacing a main filter element in a filter assembly according to the present invention, the method comprising the steps of: removing the first main filter element from the housing while leaving the safety filter element in the housing; l inserting a second main filter element into the housing.

[0129] In a preferred embodiment, the present invention is used in a safety element sealing component for an air cleaner assembly, and more specifically, in a sealing component secured to or supported by a safety element end cap.

[0130] Additionally or alternatively, the present invention can be described as a second (safety) filter cartridge that includes one or more sealing components that seal the safety filter cartridge (or element) to one or more of the first main filter cartridge and the cover for the air cleaner housing.

[0131] In a preferred embodiment, a main (or primary) filter element, which may have an end cap, and a safety (or secondary) filter element, which may have an end cap, may be mounted within the air cleaner housing. The cover may be connected to the turbo via a duct and may include a clean air outlet, which may be removably attached to the main air cleaner body or housing.

[0132] Two sets of seals can be secured to or supported by the safety element end cap. The main element can be designed to have only a sealing surface and not support or have any seals secured to it. A first seal or set of seals on the safety can prevent dirty air from passing between the safety and the cover. A second seal or set of seals can prevent dirty air from passing between the safety and the main element.

[0133] A third seal or set of seals is also possible, in which case the third set would prevent dirty air from passing between the safety and the air cleaner body or cover, which would provide an additional back-up seal.

[0134] In a preferred embodiment, the seal (e.g., a flexible or compressible member capable of forming a seal when pressed against a separate component) is a thermoplastic elastomeric seal oriented outward in a wiper configuration. The seal can be any suitable sealing material and can seal in either an inward, outward, axial, or pinch configuration. The seal can be circular or non-circular and can deviate from the axial plane (e.g., have a wavy or step-type configuration).

[0135] The safety outlet, main element sealing surface, and cover can each be either circular or non-circular. For example, any of the above-mentioned components can have an irregular shape that requires a particular installation orientation (e.g., one-fold symmetry or other asymmetric shape). The asymmetry can be achieved as a result of the seal or sealing surface being non-circular, or by some axial deviation of the seal or sealing perimeter (e.g., one or more of an asymmetric wave, ripple, and step configuration), or both the non-circular shape and the axial deviation of the sealing perimeter.

[0136] In a preferred embodiment, the media for the main element is pleated. Other media configurations for the main and / or safety elements are possible, such as fluted, corrugated, or media wrapped. The media can be cellulosic or synthetic, and may or may not have additional layers, such as support layers, liners, or other filter layers, to enhance filtration, such as microfibers or nanofibers.

[0137] In a preferred embodiment, the first set of seals and the second set of seals are vertically aligned, although they may be offset (e.g., when the circumferential outer surface of the end cap has different sized diameters at different portions along the length of the end cap). Also, while the first and second sets of seals in a preferred embodiment may be symmetric, the seals in the first and / or second sets may be asymmetric (e.g., as a result of asymmetries in the safety outlet, main element sealing surface, and / or cover).

[0138] Although preferred embodiments and implementations of the present disclosure have been described, modifications and equivalents of the disclosed concepts may readily occur to those skilled in the art, however, such modifications and equivalents are intended to be included within the scope of the claims appended hereto.

[0139] The present invention relates to an end cap including a circumferential outer surface; at least one sealing component extending along the circumferential outer or inner surface and configured to seal the end cap to the main element and / or the cover, the main element not including a sealing component fixed to the main element; It also addresses safety factors.

[0140] In a preferred embodiment, the end cap includes a first seal configured to form a seal with the main element and a second seal that forms a seal with the cover.

[0141] In a preferred embodiment, the end cap includes a single seal configured to form a seal with the main element and the cover.

[0142] In a preferred embodiment, at least one seal has one-fold rotational symmetry.

[0143] An air cleaner assembly comprising a safety element of the invention, a safety filter element of the invention, a filter system of the invention, or a filter assembly of the invention. [Brief description of the drawings]

[0144] In the following, the invention will be described with reference to the figures which show only exemplary embodiments of the invention.

[0145] [Figure 1] 1 is a schematic perspective view of a safety filter element according to the present invention;

[0146] [Diagram 2] 2 is a schematic perspective view of the safety filter element of FIG. 1 from a different perspective;

[0147] [Diagram 3] FIG. 2 is a schematic side view on the safety filter element of FIG. 1.

[0148] [Figure 4] 4 is a further schematic side view on the safety filter element of FIG. 1 taken along the direction of arrow D in FIG. 3.

[0149] [Diagram 5] 5 is a schematic cross-sectional view of the safety filter element of FIG. 1 taken along line GG of FIG. 4.

[0150] [Figure 6] 4 is a top schematic view on the safety filter element of FIG. 1 taken along the direction of arrow E in FIG. 3.

[0151] [Figure 7] 4 is a bottom view on the safety filter element of FIG. 1 taken along the direction of arrow F in FIG. 3.

[0152] [Figure 8] 5 is an enlarged schematic side view of the bottom of the safety filter element shown in FIG. 4.

[0153] [Figure 9] FIG. 6 is an enlarged schematic cross-sectional view of the bottom of the safety filter element shown in FIG. 5.

[0154] [Figure 10] FIG. 2 is a schematic side view on an end cap used as part of the safety filter element of FIG. 1.

[0155] [Figure 11] 11 is a schematic side view of the end cap of FIG. 10 from a different perspective as viewed along arrow B of FIG. 10.

[0156] [Figure 12] FIG. 11 is a schematic perspective view of the end cap of FIG. 10 .

[0157] [Figure 13] FIG. 11 is a schematic perspective view of the end cap of FIG. 10 from a different perspective.

[0158] [Figure 14] 15 is a schematic cross-sectional view of the end cap of FIG. 10 taken along line CC of FIG. 15.

[0159] [Figure 15] 11 is a schematic top view on the end cap of FIG. 10 taken along arrow A of FIG. 10.

[0160] [Figure 16] FIG. 2 is a schematic side view of an end cap used as part of the safety filter element according to FIG. 1, without a sealing material disposed thereon.

[0161] [Figure 17] 17 is a schematic side view on the end cap of FIG. 16 from a different perspective as viewed along arrow B of FIG. 16.

[0162] [Figure 18] FIG. 17 is a schematic perspective view of the end cap of FIG. 16.

[0163] [Figure 19] FIG. 17 is a schematic perspective view of the end cap of FIG. 16 from a different perspective.

[0164] [Figure 20] 22 is a schematic cross-sectional view of the end cap of FIG. 10 taken along line CC of FIG. 21. FIG.

[0165] [Figure 21] 17 is a schematic top view on the end cap of FIG. 10 taken along arrow A of FIG. 16.

[0166] [Figure 22] 26。 FIG. 42 is a schematic plan view of a portion of a first housing lid of the housing of the filter assembly of FIGS. 37-41, taken along arrow W in FIG.

[0167] [Figure 23] 23 is a schematic cross-sectional view of a portion of the first housing lid of FIG. 22 taken along line YY of FIG. 22.

[0168] [Figure 24] FIG. 23 is a schematic perspective view of a portion of the first housing lid of FIG. 22.

[0169] [Diagram 25] FIG. 23 is a schematic perspective view of a portion of the first housing lid of FIG. 22 from a different perspective.

[0170] [Figure 26] FIG. 23 is a schematic side view on a portion of the first housing lid of FIG. 22.

[0171] [Figure 27] 27 is a schematic bottom view on a portion of the first housing lid of FIG. 22 taken along arrow X of FIG. 26.

[0172] [Figure 28]33 is a schematic bottom view on an interface ring which, together with a portion of the first housing lid of FIG. 22, forms the first housing lid of the housing of the filter assembly of FIGS. 37-41 as viewed along arrow A of FIG.

[0173] [Figure 29] FIG. 29 is a schematic perspective view of the interface ring of FIG. 28.

[0174] [Diagram 30] FIG. 30 is an enlarged schematic perspective view of a detail of the interface ring of FIG. 28 as shown in FIG. 29.

[0175] [Diagram 31] 33 is a schematic cross-sectional view of the interface ring of FIG. 28 taken along line CC of FIG. 32.

[0176] [Diagram 32] 34 is a schematic top view on the interface of FIG. 28 taken along arrow B of FIG. 33.

[0177] [Diagram 33] FIG. 30 is a schematic side view of the interface ring of FIG. 29.

[0178] [Diagram 34] 42 and the interface ring of FIG. 29.

[0042] FIG. 43 is a schematic perspective view of a portion of the first housing lid of FIG. 22 and the first housing lid of the filter assembly of FIGS.

[0179] [Diagram 35] FIG. 35 is a schematic perspective view of the first housing lid of FIG. 34 from a different perspective.

[0180] [Diagram 36] FIG. 35 is a schematic cross-sectional view of the first housing lid of FIG. 34.

[0181] [Figure 37] FIG. 2 is a schematic plan view on a filter assembly according to the present invention.

[0182] [Figure 38] FIG. 38 is a schematic side view of the filter assembly of FIG. 37.

[0183] [Figure 39] 38 is a schematic cross-sectional view of the filter assembly of FIG. 37 taken along line CC of FIG. 37.

[0184] [Diagram 40] FIG. 40 is an enlarged detail of the upper part of the schematic cross-sectional view of FIG. 39.

[0185] [Diagram 41] FIG. 40 is an enlarged detail of the upper part of the schematic cross-sectional view of FIG. 39.

[0186] [Diagram 42] FIG. 45 is a schematic bottom view of the main filter element of the filter assembly of FIGS. 37-41, taken along arrow B in FIG. 44.

[0187] [Diagram 43] 43 is a schematic cross-sectional view of the main filter element of FIG. 42 taken along line EE of FIG. 42.

[0188] [Diagram 44] FIG. 43 is a schematic side view of the main filter element of FIG. 42.

[0189] [Diagram 45] 45 is a schematic cross-sectional view of the main filter element of FIG. 42 taken along line CC in FIG. 44.

[0190] [Figure 46] FIG. 43 is a schematic perspective view of the main filter element of FIG. 42.

[0191] [Figure 47] 45 is a schematic top view of the main filter element of FIG. 42 taken along arrow A of FIG. 44.

[0192] [Figure 48] FIG. 11 is a schematic cross-sectional view on a further embodiment of the main filter element.

[0193] [Figure 49] FIG. 49 is a schematic perspective view of the main filter element of FIG. 48.

[0194] [Figure 50] FIG. 11 is a schematic cross-sectional view on a further embodiment of the main filter element.

[0195] [Figure 51] FIG. 51 is a schematic perspective view of the main filter element of FIG. 50.

[0196] [Figure 52] 55 is a schematic cross-sectional view of a further embodiment of a filter assembly taken along line CC of FIG. 54.

[0197] [Figure 53] FIG. 53 is a schematic side view of the filter assembly of FIG. 52.

[0198] [Figure 54] 54 is a schematic top view on the filter assembly of FIG. 52 taken along arrow B of FIG. 53.

[0199] [Figure 55] FIG. 53 is an enlarged schematic cross-sectional view of the bottom of the filter assembly according to FIG. 52.

[0200] [Figure 56] 11 is a schematic cross-sectional view of a further embodiment of a safety filter element disposed within a housing. FIG.

[0201] [Figure 57] FIG. 57 is an enlarged detail of the schematic cross-sectional view of FIG. 56.

[0202] [Figure 58]FIG. 13 is a schematic cross-sectional view of a further embodiment of a safety filter element disposed in a further embodiment of a main filter element disposed in a housing;

[0203] [Figure 59] FIG. 59 is an enlarged detail of the schematic cross-sectional view of FIG. 58.

[0204] [Figure 60] FIG. 59 is a schematic cross-sectional view of the main filter element used in FIG. 58.

[0205] [Figure 61] FIG. 59 is a schematic cross-sectional view of the safety filter element used in FIG. 58.

[0206] [Figure 62] FIG. 62 is an enlarged detail of the schematic cross-sectional view of FIG. 61.

[0207] [Figure 63] 13 is a schematic cross-sectional view of a further embodiment of a safety filter element disposed in a further embodiment of a main filter element disposed in a housing. FIG.

[0208] [Figure 64] FIG. 64 is an enlarged detail of the schematic cross-sectional view of FIG. 63.

[0209] [Figure 65] 11 is a schematic cross-sectional view of a further embodiment of a safety filter element disposed within a housing. FIG.

[0210] [Figure 66] FIG. 66 is an enlarged detail of the schematic cross-sectional view of FIG.

[0211] [Figure 67] 11 is a schematic side view on a further embodiment of a safety seal element according to the present invention disposed within a housing.

[0212] [Figure 68]FIG. 68 is a schematic cross-sectional view of the safety filter element of FIG. 67.

[0213] [Figure 69] FIG. 68 is an enlarged detail of the schematic cross-sectional view of FIG. 67.

[0214] [Figure 70] 11 is a schematic cross-sectional view of a further embodiment of a safety filter element disposed within a housing. FIG.

[0215] [Figure 71] FIG. 71 is an enlarged detail of the schematic cross-sectional view of FIG. 70.

[0216] [Figure 72] FIG. 71 is a schematic cross-sectional view of the safety filter element used in FIG. 70.

[0217] [Figure 73] FIG. 73 is an enlarged and detailed schematic cross-sectional view of FIG. 72.

[0218] [Figure 74] FIG. 13 is a schematic top view on a further embodiment of the main filter element.

[0219] [Figure 75] 79 is a schematic side view on the main filter element of FIG. 74 taken in the direction of arrow F in FIG. 79.

[0220] [Figure 76] 79 is a schematic cross-sectional view of the main filter element of FIG. 74 taken along line HH of FIG. 79.

[0221] [Figure 77] FIG. 75 is a schematic perspective view of the main filter element of FIG. 74.

[0222] [Figure 78] FIG. 75 is a schematic perspective view of the main filter element of FIG. 74 from a different perspective.

[0223] [Figure 79] FIG. 75 is a schematic bottom view on the main filter element of FIG. 74.

[0224] [Figure 80] FIG. 78 is an enlarged detail of the schematic perspective view of FIG. 77.

[0225] [Figure 81] FIG. 77 is an enlarged detail of the schematic cross-sectional view of FIG. 76.

[0226] [Figure 82] 11 is a schematic top view on a further embodiment of a safety filter element. FIG.

[0227] [Figure 83] 88 is a schematic side view on the safety filter element of FIG. 82 taken in the direction of arrow F of FIG. 87.

[0228] [Figure 84] 87 is a schematic cross-sectional view of the safety filter element of FIG. 82 along line GG of FIG. 87.

[0229] [Figure 85] FIG. 83 is a schematic perspective view of the safety filter element of FIG. 82.

[0230] [Figure 86] 83 is a schematic perspective view of the safety filter element of FIG. 82 from a different perspective.

[0231] [Figure 87] FIG. 83 is a schematic bottom view on the main filter element of FIG. 82.

[0232] [Figure 88] FIG. 85 is an enlarged detail of the schematic cross-sectional view of FIG. 84.

[0233] [Figure 89] FIG. 86 is an enlarged detail of the schematic perspective view of FIG. 85.

[0234] [Figure 90] 11 is a schematic side view on a further embodiment of a filter assembly according to the present invention. FIG.

[0235] [Figure 91] FIG. 91 is a schematic top view on the filter assembly according to FIG. 90.

[0236] [Figure 92] 92 is a schematic cross-sectional view of the filter assembly of FIG. 90 taken along line AA of FIG. 91.

[0237] [Figure 93] FIG. 1 is a schematic perspective view of a filter system according to the present invention;

[0238] [Figure 94] FIG. 94 is a schematic perspective view of the filter system of FIG. 93 from a different perspective.

[0239] [Figure 95] 97 is a schematic cross-sectional view of the filter system of FIG. 93 taken along line AA of FIG. 96.

[0240] [Figure 96] FIG. 94 is a schematic bottom view on the filter system of FIG. 93.

[0241] [Figure 97] FIG. 94 is a schematic side view on the filter system of FIG. 93.

[0242] [Figure 98] FIG. 94 is a schematic top view on the filter system of FIG. 93.

[0243] [Figure 99] FIG. 96 is an enlarged detail of the schematic cross-sectional view of FIG. 95.

[0244] [Figure 100] FIG. 93 is an enlarged detail of the schematic cross-sectional view of FIG. 92.

[0245] [Figure 101] 4 is a schematic cross-sectional view on a further embodiment of a filter assembly according to the present invention. FIG.

[0246] [Figure 102] 102 is a schematic cross-sectional view of the bottom of the safety filter element of the filter assembly of FIG. 101.

[0247] [Figure 103] FIG. 13 is a schematic perspective view on a safety filter element according to a further embodiment of the present invention.

[0248] [Figure 104] FIG. 104 is a schematic perspective view of the safety filter element of FIG. 103 from a different perspective.

[0249] [Figure 105] 1 is a schematic cross-sectional top view of a further embodiment of a filter assembly according to the present invention;

[0250] [Fig. 106] 2 is a schematic cross-sectional view of a further embodiment of a filter assembly according to the present invention;

[0251] [Figure 107] FIG. 107 is a schematic exploded cross-sectional view of the filter assembly of FIG. 106.

[0252] [Figure 108] FIG. 107 is a schematic enlarged cross-sectional view of the bottom of the filter assembly of FIG. 106.

[0253] [Fig. 109] FIG. 107 is a schematic enlarged cross-sectional view of the top of the filter assembly of FIG. 106.

[0254] [Figure 110A] FIG. 107 is a schematic perspective view from the top on an end cap of the safety filter element of the filter assembly of FIG. 106. [Figure 110B]FIG. 107 is a schematic perspective view from the bottom on the end cap of the safety filter element of the filter assembly of FIG. 106.

[0255] [Fig. 111A] FIG. 107 is a schematic perspective view from the top on a further end cap of the safety filter element of the filter assembly of FIG. [Figure 111B] FIG. 107 is a schematic perspective view from the bottom on a further end cap of the safety filter element of the filter assembly of FIG.

[0256] [Figure 112] FIG. 107 is a schematic perspective view of a safety filter element of the filter assembly of FIG. 106.

[0257] [Figure 113] FIG. 107 is a schematic perspective view of an end cap of the main filter element of the filter assembly of FIG. 106.

[0258] [Fig. 114] FIG. 107 is a schematic perspective view of a further end cap of the main filter element of the filter assembly of FIG.

[0259] [Fig. 115] FIG. 107 is a schematic perspective view of the main filter element of the filter assembly of FIG.

[0260] [Fig. 116] FIG. 107 is a schematic perspective cross-sectional view of a safety filter element inserted into a housing of the filter assembly of FIG. 106 and on a bottom end of the housing.

[0261] [Fig. 117] FIG. 107 is a schematic perspective cross-sectional view of a safety filter element inserted into a housing of the filter assembly of FIG. 106, with the main filter element beginning to be inserted, and on the top end of the housing.

[0262] [Fig. 118]FIG. 107 is a schematic perspective cross-sectional view of a safety filter element inserted into a housing of the filter assembly of FIG. 106, with the main filter element in its end position, and the housing on its bottom end.

[0263] [Figure 119] FIG. 107 is a schematic perspective cross-sectional view of a safety filter element inserted into a housing of the filter assembly of FIG. 106 with the main filter element inserted and the housing lid in the process of being closed, on the top end of the housing.

[0264] [Figure 120] FIG. 107 is a schematic perspective cross-sectional view of a housing lid of the filter assembly of FIG. 106.

[0265] [Figure 121] FIG. 107 is a schematic perspective view of a housing lid of the filter assembly of FIG. 106.

[0266] [Figure 122] FIG. 107 is a schematic perspective cross-sectional view of the filter assembly of FIG. 106 in an improperly installed state.

[0267] [Figure 123] 2 is a schematic cross-sectional view of a further embodiment of a filter assembly according to the present invention;

[0268] [Figure 124] FIG. 124 is a schematic exploded view of the filter assembly of FIG. 123.

[0269] [Fig. 125] FIG. 124 is a schematic enlarged cross-sectional view of the bottom of the filter assembly of FIG. 123.

[0270] [Fig. 126A] FIG. 124 is a schematic perspective view from the top on the end cap of the safety filter element of the filter assembly of FIG. 123. [Fig. 126B]FIG. 124 is a schematic bottom perspective view on an end cap of the safety filter element of the filter assembly of FIG. 123.

[0271] [Fig. 127A] FIG. 124 is a schematic perspective view from the top on a further end cap of the safety filter element of the filter assembly of FIG. 123. [Fig. 127B] FIG. 124 is a schematic bottom perspective view on a further end cap of the safety filter element of the filter assembly of FIG. 123.

[0272] [Figure 128] FIG. 124 is a schematic enlarged cross-sectional view of the bottom of the filter assembly of FIG. 123.

[0273] [Figure 129] FIG. 124 is a schematic perspective view of a safety filter element of the filter assembly of FIG. 123.

[0274] [Fig. 130A] FIG. 124 is a schematic perspective view from the top on the end cap of the main filter element of the filter assembly of FIG. 123. [Fig. 130B] FIG. 124 is a schematic perspective view from the bottom on the end cap of the main filter element of the filter assembly of FIG. 123.

[0275] [Fig. 131A] FIG. 124 is a schematic perspective view from the top on a further end cap of the safety filter element of the filter assembly of FIG. 123. [Fig. 131B] FIG. 124 is a schematic perspective view from the bottom on a further end cap of the safety filter element of the filter assembly of FIG. 123.

[0276] [Fig. 132] FIG. 124 is a schematic perspective view of a main filter element of the filter assembly of FIG. 123.

[0277] [Fig. 133]FIG. 124 is a schematic perspective view of the main filter element of the filter assembly of FIG. 123 from a different perspective.

[0278] [Fig. 134] FIG. 106 is a schematic cross-sectional view of the top of a further embodiment of a filter assembly according to the present invention of FIG. 105 in a correctly installed state.

[0279] [Fig. 135] FIG. 106 is a schematic cross-sectional view of the top of a further embodiment of a filter assembly according to the present invention of FIG. 105 in an incorrectly installed state (missing the safety filter element). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0280] Figures 1 to 21 show a safety filter element 1. Together with a main filter element 2 shown in Figures 42 to 47, the safety filter element 1 can form a filter system according to the present invention. Together with a housing 5 shown in Figures 37 to 41 or Figures 52 to 55, the filter system can form a filter assembly according to the present invention.

[0281] The safety filter element 1 extends along an axis A. The safety filter element 1 comprises:

[0282] A safety filter media 6. The safety filter element 1 includes a safety filter element circumferential surface 7, which includes several surface sections 8, 9, 10, 110. At least one of the surface sections 8, 9, 10, 110, i.e., the surface sections 8, 9, 10, 110, is arranged such that a normal vector N to the surface section 8, 9, 10, 110 is oriented to point toward the outside of the safety filter element 1. At least one sealing component 11 extends along the safety filter element circumferential surface 7. The surface sections 8, 9, 10, 110 and their normal vector N are best seen in Figs. 16-21, which show an end cap 13 of a safety filter element without a sealing component 11, as indicated by the dashed lines in Figs. 16-21. The surface sections 8, 9, 10, 110 do not have to be designed to be identifiable by design features such as rims, edges, etc., but can be imaginary surface sections on a uniform surface. Reference to the surface sections 8, 9, 10, 110 is made herein simply as a means of describing the geometry of the safety filter element circumferential surface 7.

[0283] In the embodiment shown in Figures 16 to 21, the safety filter element circumferential surface 7 has a surface section 9 offset from a surface section 110 in the direction of the axis A of the safety filter element. The surface section 110 constituting part of the safety filter element circumferential surface is arranged to form part of a ring-shaped surface outside a cylinder, while the further surface section 9 is arranged to form part of a different ring-shaped surface outside the cylinder, while a first angled surface section 8 connects the surface section 110 with one offset surface section 9 on one side, while a second angled surface section 10 connects the surface section 110 with one offset surface section 9 on the other side. Thus, the angled surface sections 8, 10 look like a ramp leading from the ring in which the surface section 110 is arranged, up to the offset surface section 9 on one side, down from the offset surface section 9 and back to the ring in which the surface section 110 is arranged. In such a design, all normal vectors N to the respective surface sections 8 , 9 , 10 , 110 are oriented to point towards the outside of the safety filter element 1 .

[0284] In the embodiment of Fig. 1, in addition to one sealing component 11, a housing sealing component 12 is provided on the safety filter element 4. In the embodiment shown in Fig. 1, the housing sealing component 12 is manufactured integrally with the sealing component 11.

[0285] 1, for example, a safety filter element end cap 13 is provided that is disposed on one end of the safety filter media 6. The safety filter element circumferential surface 7 is disposed on the safety filter element end cap 13.

[0286] In the embodiment shown in FIG. 1, for example, safety filter media 6 has an interior space 14 and safety filter element end cap 13 has an outlet opening 15 that communicates with interior space 14 .

[0287] In the embodiment shown in Figures 1 and 5, the safety filter media 6 has the shape of a hollow cylinder.

[0288] In the embodiment shown in Figures 1 and 16-21, the safety filter element circumferential surface 7 forms a contour shape with single-fold rotational symmetry.

[0289] The safety filter element 1 has a further safety filter element end cap 16 which is of closed design and is arranged opposite the safety filter element end cap 13 having the outlet opening 15 .

[0290] 42-47, main filter element 2 has main filter media 17. Main filter element 2 extends along longitudinal axis D, which is the same axis as longitudinal axis A in the assembled state of the filter system.

[0291] The main filter media 17 has a main filter media interior space 18. When assembled to form a filter system according to the invention, or when the filter system is fully disposed within the housing 5 to form a filter assembly according to the invention, the safety filter media 6 is, in the embodiment of Figures 1-47, at least partially disposed completely inside the main filter media interior space 18.

[0292] 1-47 the main filter element 2 comprises a main filter element circumferential surface 19. The main filter element circumferential surface 19 comprises several surface sections 120, 121, 122, whereby at least one of the surface sections 120, 121, 122, i.e. the surface sections 120, 121, 122, is arranged such that a normal vector N2 to the surface sections 120, 121, 122 is oriented pointing towards the main filter media interior space 18. In the assembled state of the filter system the sealing component 11 of the safety filter element 1 is in sealing contact with the main filter element circumferential surface 19.

[0293] 1-47, there is provided a main filter element end cap 20 disposed at one end of the main filter media 17. The main filter element circumferential surface 19 is disposed on the main filter element end cap 20. The main filter element end cap 20 has an outlet opening 21 that leads to the main filter media interior space 18.

[0294] The main filter media 17 has the shape of a hollow cylinder. A further main filter element end cap 22 is provided, which is arranged closed at an opposite end of the main filter media 17 compared to the main filter element end cap 21.

[0295] The safety filter element 1 has a first projection in the form of a first wing 23 in the form of a radially projecting wing and a second projection in the form of a second wing 24, whereby the first wing 23 is smaller than the second wing 24. The main filter element 2 has a first recess 25 and a second recess 26, whereby the first recess 25 can accommodate the first wing 23 but not the second wing 24, and the second recess 25 can accommodate the second wing 24. The first recess 25 and the second recess 26 are formed in a circular wall 28 that protrudes axially from a bottom surface 27 of the main filter element end cap 21. This design ensures that the safety filter element 1 can only be inserted into its final position in the main filter element 2 in one specific rotational relationship.

[0296] In the embodiment shown in Figures 1-47, the housing 5 includes a central housing portion 30. An inlet tube 31 is disposed in the central housing portion 30. The fluid to be filtered enters the housing 5 through the inlet tube 31. The housing 5 further includes a first housing lid 32 having an outlet tube 33 formed therein. The filtered fluid exits the housing 5 through the outlet tube 33. An interface ring 34 is attached to the portion 132 of the first housing lid 32. The housing 5 further includes a second housing lid 35. The second housing lid 35 in the embodiment shown in Figures 1-47 includes a drain tube 36 that can be used to drain debris or liquid collected from the fluid to be filtered before the fluid passes through the main filter element 2.

[0297] 1, for example, shows that a locking pin 40 is provided on the safety filter element end cap 13 that projects into the outlet opening 15 of the safety filter element end cap 13. FIG. 29, for example, shows that the interface ring 34 includes a plug-in channel 37 that terminates in a receiving port 38. When the safety filter element 1 is inserted into the housing 5, the locking pin 40 can be aligned with the receiving port 38 by rotating the safety filter element 1 inside the housing 5 about its axis A. Once aligned with the receiving port 38, a further combination of linear and rotational movements of the safety filter element 1 relative to the housing 1 can cause the respective locking pin 40 to enter the plug-in channel 37, thereby locking the safety filter element 1 to the housing 5. A flexible knob structure 137 is provided at the end of the plug-in channel 37 to hold the locking pin 40 in the lowermost portion of the plug-in channel 37.

[0298] When the safety filter element 1 is locked in the housing 5, the undulating housing sealing component 12 comes into contact with the undulating sealing surface 39 on the interface ring 34, thereby sealing the safety filter element 1 against the housing 5 and preventing any fluid from passing from outside the safety filter element 1 through the safety filter element 1 into the outlet tube 33 of the first housing lid 32. Proper alignment of the undulating housing sealing component 12 with the undulating sealing surface 39 of the interface ring 34 can be achieved, on the one hand, by a suitable relative positioning of the locking pin 40 with respect to the undulating housing sealing component 12 and, on the other hand, by a suitable alignment of the ends of the plug-in channels 37 and the undulating sealing surface 39. In the embodiment shown in Figures 23 and 25, the undulating sealing surface 39 is provided by a ribless surface arranged between a series of ribs each terminating in a ribless surface.

[0299] 28-33 show the interface ring 34 having ribs 41 pointing toward the safety filter element interior space 14. Each rib 41 has a tip 43 and an angled outwardly facing surface 42 that is located inwardly of the connection between the respective rib 41 and the remainder of the interface ring 34. The angled outwardly facing surfaces 42 of the ribs 41 facilitate assembly of the safety filter element 1 into the housing 5. FIG. 40 shows that the ribs 41 can be used to engage a wall surrounding the outlet opening 15 of the safety element 1 and to center the safety filter element 1 as it is moved toward the first housing lid 32.

[0300] Starting with the empty housing 5 and second housing lid 35 removed, the safety filter element 1 is first inserted in a linear motion into the housing 5. If the safety filter element 1 is not perfectly aligned during this linear motion, the ribs 41 can be used to center the safety filter element 1 as it approaches the first housing lid 32.

[0301] If the pin 40 happens to be aligned with the receiving opening 38 during this insertion, the safety filter element 1 can be further inserted into the housing 5 by a combination of linear and rotational motions that insert the pin 40 into the plug channel 37 and move it to the end of the plug channel 37, which brings the wavy housing sealing component 12 into contact with the wavy sealing surface 39 on the interface ring 34.

[0302] If the pins 40 are not aligned with the receptacles 38, the pins will first abut the wall of the interface ring 34 between the receptacles 38. By rotating the safety filter element 1 relative to the housing, the pins 40 can be aligned with the receptacles 38, and the safety filter element 1 can be further inserted into the housing 5 by a combination of linear and rotational movements that insert the pins 40 into the plug channels 37 and move them to the end of the plug channels 37, which brings the wavy housing sealing component 12 into contact with the wavy sealing surface 39 on the interface ring 34.

[0303] Figure 40 shows the final position of the top of the safety filter element 1 and its cooperation with the interface ring 34 and therefore the first housing lid 32. Figure 40 shows that several sealing effects are created. The housing sealing component 12 is designed as a double lip seal (having two lips) which seals with a radial sealing force against the wavy sealing surface 39. Furthermore, the radial protrusion 45 of the material forming the sealing component 11, the wings 23, 24 and the housing sealing component 12 abuts against the top rim of the circular wall 44 and therefore acts as an additional axial seal.

[0304] After the safety filter element 1 is fully inserted, the main filter element 2 is inserted by linear movement into the housing 5. If during this insertion, the smaller wing 23 happens to align with the smaller first recess 25 and the larger wing 24 happens to align with the larger second recess 26, the linear movement of the main filter element into the housing 5 can be continued until the main filter element reaches its final position shown in Figure 39. If the smaller wing 23 does not align with the smaller first recess 25 and the larger wing 24 does not align with the larger second recess 26, the wings 23, 24 will abut against the circular wall 28 on the bottom surface 27 of the main filter element 2. By rotation of the main filter element 2 relative to the housing of the safety filter element 1 (see arrow F in FIG. 39 ), the smaller wing 23 is aligned with the smaller first recess 25 and the larger wing 24 is aligned with the larger second recess 26, and the main filter element 2 can be inserted further into the housing 5 by linear motion until it reaches the position shown in FIG. 39 .

[0305] When the main filter element 1 reaches its final position shown in Fig. 39, the sealing component 11, which together with the safety filter element circumferential surface 7 forms a contour shape with one-fold rotational symmetry, comes into contact with the main filter element circumferential surface 19 on the main filter element 2, which also forms a contour shape with one-fold rotational symmetry, thereby sealing the main filter element 1 against the safety filter element 1 and preventing any fluid from passing from the outside of the main filter element 2 through the main filter medium 17 into the main filter medium space 18. By a proper relative positioning of the small wing 23 and the large wing 24 with respect to the surface sections 8, 9, 10, 110, a proper alignment of the sealing component 11 with a specific shape with the counter surface on the main filter element 2 can be achieved, which on the one hand gives the sealing component 11 its contour shape with one-fold rotational symmetry and a proper alignment of the small first recess 25 and the small second recess 26 as well as the main filter element circumferential surface 19 on the main filter element 2.

[0306] Figure 40 shows that several sealing effects occur between the main filter element 2 and the safety filter element 1. The sealing component 7 is designed as a lip seal that seals the main filter element circumferential surface 19 of the main filter element 2 with a radial sealing force. Furthermore, a radial protrusion 45 of the material forming the sealing component 11, the wings 23, 24 and the housing sealing component 12 abuts against a top rim of a circular wall 46 that is arranged radially inside the circular wall 28 on the bottom surface 27 of the main filter element, thus acting as an additional axial seal. The radial protrusion 45 forms a radially extending safety filter element abutment surface. The top rim of the circular wall 46 forms a main filter element abutment surface that can come into contact with the safety filter element contact surface, and the abutment of the main filter element abutment surface with the safety filter element abutment surface limits the relative movement of the main filter element with respect to the safety filter element along the longitudinal axis. Thus, the design shown in Figure 40 can be understood to be a design in which the safety filter element 1 has a first safety filter element circumferential surface 7 as described above, and has a second safety filter element circumferential surface (the surface of protrusion 45), whereby the first sealing component 11 (the portion of the sealant on the safety filter element circumferential surface 7) extends along the first safety filter element circumferential surface 7, and the second sealing component (the portion of the sealant on protrusion 45) extends along the second safety filter element circumferential surface. In the design shown in Figure 40, the first sealing component and the second sealing component are part of the same sealant.

[0307] The first housing lid 32 has an inwardly projecting wall 47. As part of the projecting wall 47 a knob 48 is provided, which is flush with the projecting wall 47 and is formed by an interruption in the projecting wall 47. A hollow cylinder 49 is provided projecting from the bottom surface 27. The hollow cylinder 49 is formed to take up the knob 48 once the main filter element 2 has reached its end position as shown in Figure 14. There are the following: l a fixed spatial relationship between the cylinder 49 arranged on the bottom surface 27 and the first recess 25 and the second recess 26; l a fixed spatial relationship between the wings 23, 24 and the locking pin 40 located on the safety filter element end cap 13; The ends of the knob 48 and plug channel 37 disposed on the first housing lid 32 and the interface ring 34 Assuming that is present, the engagement between the cylinder 49 and the knob 48 also indicates that the main filter element 2, the safety filter element 1, and the first housing lid 32 are all in position relative to one another.

[0308] The fluid to be filtered is introduced into the housing 5 of the assembled filter assembly 4 via the inlet tube 31. The fluid to be filtered enters the circumferential space between the inner facing surface of the central housing portion 30 and the outer facing surface of the main filter media. Depending on the orientation and placement of the inlet tube, the fluid to be filtered can be made to swirl around the outer facing surface of the main filter media. Creating a fluid swirl can help transport larger particles in the fluid radially outward toward the inner facing surface of the central housing portion 30. A circular baffle 150 disposed on the second housing lid 35 keeps larger particles accumulated in the area of ​​the second housing lid 35 away from the main filter media 17.

[0309] Fluid to be filtered passes through the main filter media 17 and the safety filter media 6 into the safety filter media interior space 14 through an outlet tube 33 in the first housing lid 32 and out the outlet opening 15 in the safety filter media end cap 13 .

[0310] The sealing component 11 prevents any fluid from entering the main media interior space 18 in any other manner other than through the main media 17. The housing sealing component 12 prevents any fluid from entering into the outlet opening 15 of the safety media end cap 13 in any other manner other than through the safety media 6.

[0311] If the main filter element 2 needs to be replaced, for example when the main filter media 17 becomes clogged, the second housing lid 35 can be opened and the main filter element 2 can be pulled out in a linear movement. As the main filter element 2 is pulled out, the safety filter element 1 prevents any undesirable items, particles or fluid droplets from entering the outlet tube 33 of the first housing lid 32. A new main filter element 2 is then introduced as described above.

[0312] As can be best seen in Figures 39 and 40, the presence of the safety filter element 1 determines the positioning of the main filter element 2 and therefore the positioning of the second housing lid 35, since the main filter element 2 is located on the radially projecting wall 45 of the safety filter element 1 and the second housing lid 35 is located on the main filter element 2. If the safety filter element 1 is missing, the main filter element 2 will slide deeper into the central housing part 30, deeper towards the first housing lid 32 and further away from the second housing lid 35. This misalignment can be made noticeable by the user if, for example, only the attachment means for the first housing lid 32 (not shown) could engage, the main filter element 2 would be in the position shown in Figure 40 but not deeper in the central housing part 30 (closer to the first housing lid 32).

[0313] Baffle 151 prevents fluid entering the housing via inlet tube 31 from flowing directly onto the outer surface of main filter media 17, but diverts the fluid flow.

[0314] The embodiment of the main filter element 2 shown in Figures 48 and 49 differs from that shown in Figures 42 to 47 mainly by the design of the end cap 22. In the design shown in Figures 48 and 49, a protrusion 200 is provided. A recess 201 is provided in the protrusion 200. The recess 201 is oriented radially with respect to the axis D of the main filter element 2.

[0315] The embodiment of the main filter element 2 shown in Figures 50 and 51 differs from the embodiment shown in Figures 48 and 49 in that the diameter and length of the main filter media 17 are wider, thicker and shorter in the embodiment of Figures 50 and 51 compared to the embodiment of Figures 48 and 49. Also, the protrusion 200 has four recesses 201 provided therein. Each recess 201 is oriented radially with respect to the axis D of the main filter element 2. In addition, the end cap 22 has ledges 202 provided to interact with the inner facing surface of the second housing lid 35 to mitigate relative movement between the end cap 22 and the second housing lid 35, in particular to reduce rattle noise.

[0316] The filter assembly 4 shown in Figures 52-55 differs from the filter assembly 4 shown in Figures 37-41 primarily in the size and shape of the safety filter element 1 and main filter element 2, and by the placement of the pre-filter 300. The embodiment of Figures 52-55 also has a pressure sensor. Also, the design of the main filter element end cap 22 and second housing lid 35 is different.

[0317] As becomes apparent from a comparison of Figures 40 and 55, the overall operation of the sealing component 11 and the housing sealing component 12 is the same, however, in both embodiments, reference is made to the descriptions of Figures 37 to 41 for a detailed description of the interaction of the safety filter element 1 and main filter element 2 and the first housing lid 32.

[0318] 52-54 show that the main filter element end cap 22 includes an outward protrusion 200. In the assembled state, the protrusion 200 engages with a dome-shaped receiver 210 on the second housing lid 35. The engagement stabilizes the position of the end of the main filter element 2 with the end cap 22 relative to the housing 5. The receiver in the embodiment shown in FIGS. 52-54 includes a through hole 211. The following positions are provided: l a locked position in which the latch 230 is disposed in the through hole 211 and the recess 201 of the protrusion 200 of the main filter end cap 22; and l Release position where latch 230 is not positioned within recess 201 A latch 230 is provided that can be positioned in the

[0319] 55, the presence of the safety filter element 1 determines the placement of the main filter element 2, and therefore the placement of the second housing lid 35, because the main filter element 2 is located on the radially projecting wall 45 of the safety filter element 1 and the second housing lid 35 is located on the main filter element 2. If the safety filter element 1 is missing, the main filter element 2 will slide deeper into the central housing part 30, deeper towards the first housing lid 32, and farther away from the second housing lid 35. This misalignment can be made noticeable by the user, for example, if the main filter element 2 is too deep in the central housing part if the latch 230 cannot engage the recess 201.

[0320] Figures 56 and 57 show a further embodiment of the safety filter element 1. In the embodiment of Figures 56 and 57 the design of the sealing component 11 and the design of the housing sealing component have been modified compared to the embodiment shown in Figures 1 to 21. The sealing component 11 in the embodiment of Figures 56 to 57 is an axial seal, which is simply provided by a radial protrusion 45. The main filter element 2 seals against this sealing component 11 via a circular wall 46 which is arranged radially inside a circular wall 28 on the bottom surface 27 of the main filter element which seals against the radial protrusion 45.

[0321] In the embodiment of Figures 56 and 57, the housing sealing component 12 seals against a sealing surface 39 provided on the circular wall 44. The housing sealing component now functions as a radial-axial seal. The circular wall 44 is chamfered at its tip. The tip of the circular wall 44 seals against a radial protrusion 45 to provide an additional axial seal.

[0322] 58-62 show further embodiments of the safety filter element 1. In the embodiment of Figs. 58-62, in particular the design of the sealing component 11 and the design of the end cap 13 have been modified when compared to the embodiment shown in Figs. 1-21. The safety filter element circumferential surface 7 in the embodiment of Figs. 58-62 is arranged on a large rim 113 of the end cap 13, which projects radially beyond the outer periphery of the main filter medium 17. The safety filter element circumferential surface 7 has a surface section with a normal vector N directed towards the safety filter element inner space 14. The main filter element circumferential surface 19 is provided on an angled rim projecting from the main filter end cap 20. The embodiment of Figs. 58-62 shows a safety filter element 1 suitable for use in a filter assembly, which comprises a main filter element 2, which comprises a main filter medium 17, and a safety filter element 1, which extends along an axis A, and which is characterized by the following: l Safety filter media 6, at least one safety filter element end cap 13, the safety filter element end cap 13 including a safety filter element circumferential surface 7; at least one sealing component 11 extending along the safety filter element circumferential surface 7; Includes.

[0323] Figures 63 and 64 show further embodiments of the safety filter element 1. In the embodiment of Figures 63 and 64, in particular the design of the sealing component 11 and the design of the end cap 13 have been modified when compared to the embodiment shown in Figures 1 to 21. The safety filter element circumferential surface 7 in the embodiment of Figures 58 to 62 is arranged on a large rim 113 of the end cap 13 that projects radially beyond the outer periphery of the main filter medium 17. The safety filter element circumferential surface 7 has a surface section with a normal vector N that is directed away from the safety filter element inner space 14. The main filter element circumferential surface 19 is provided on an angled rim that projects from the main filter end cap 20. Furthermore, the sealing component 11 in the embodiment of Figures 58 to 62 is a lip seal, while the sealing component 11 in the embodiment of Figures 63 to 64 is a block seal. Furthermore, the housing sealing component 12 in the embodiment of Figures 58 to 62 is a lip seal, while the housing sealing component 12 in the embodiment of Figures 63 to 64 is a block seal.

[0324] 65 and 66 show a further embodiment of the safety filter element 1. In the embodiment of Fig. 65 and Fig. 66, the design of the sealing component 11 and the design of the housing sealing component are changed when compared to the embodiment shown in Fig. 1 to Fig. 21. The sealing component 11 in the embodiment of Fig. 65 and Fig. 66 is a block seal, while the sealing component 11 in the embodiment of Fig. 1 to Fig. 21 is a lip seal. The housing sealing element 12 is also designed as a block seal. In addition, the housing sealing element 12 is arranged facing radially inward, while in the design of Fig. 1 to Fig. 21 the housing sealing element 12 faces radially outward.

[0325] The design of the safety filter element 1 shown in Figures 67-69 is similar to that of the safety filter element 1 in the embodiment of Figures 65-66 in the sense that the sealing component 11 in the embodiment of Figures 67-69 is a block seal and the housing seal element 12 is also designed as a block seal arranged facing radially inward. The locking pin 40 is located on the outer periphery of the safety filter element end cap 13.

[0326] The design of the safety filter element 1 shown in Figures 70-73 is similar to that of the safety filter element 1 in the embodiment of Figures 65-66 in the sense that the sealing component 11 in the embodiment of Figures 70-73 is a block seal. The housing sealing component 12 is designed as a pinch seal (a seal that is axially pressed between two surfaces).

[0327] Figures 90 to 92 show a further embodiment of a filter assembly according to the invention in which a filter system 3 according to the invention is used, which is shown in Figures 93 to 99. The filter assembly of Figures 90 to 92 and the filter system 3 of Figures 93 to 99 use an embodiment of a safety filter element 1 according to the invention as shown in Figures 82 to 89 and an embodiment of a main filter element 2 according to the invention as shown in Figures 74 to 81.

[0328] The safety filter element 1 of Figures 82-89 has a support cage 106 that internally supports the safety filter media 6. As can be best seen in Figure 89, the support cage 106 is attached to the safety filter element end cap 13 and extends away from the safety filter element end cap 13 into the safety filter element interior space 14.

[0329] The safety filter element circumferential surface 7 in the embodiment of Figures 82-89 is ring-shaped and includes a surface section 8 arranged such that a normal vector N to the surface section 8 is oriented parallel to the axis A. The sealing component 11 is provided by a wall-like sealing structure that surrounds the safety filter media 6 like a ring. The housing sealing component 12 is a double lip seal. As best seen in Figure 89, the design of the housing sealing component 12 in the embodiment of Figures 82-89 is similar to the design of the sealing component 11 in the embodiment of Figures 1-21, and comprises a surface section 112 that is offset from the remainder of the surface section 112 and is adjacent to the remainder by angled surface sections 115, 116.

[0330] The main filter element 2 of FIGS. 74-81 has a ledge 202 that is disposed on the main filter element end cap 22, as in the embodiment shown in FIG.

[0331] As best seen in Figures 80 and 81, the main filter element circumferential surface 19 is provided by material 119 disposed on the main filter element end caps 20. Figure 99 shows how the sealing component 11 interacts with the material 119 that forms the main filter element circumferential surface 19.

[0332] In the embodiment of the filter assembly 4 as shown in Figures 90, 91, 92, 100, the inlet tube 31 and the outlet tube 32 are both located at the top of the housing. In this design, the central housing part is cup-shaped and closed at the top by a first housing lid. No second housing lid is provided. The inlet tube 31, by its unique three-dimensional design, directs the fluid to be filtered into the space between the inwardly facing surface of the central housing part 30 and the outwardly facing surface of the main filter element 2.

[0333] As can be best seen in FIG. 100, the presence of the safety filter element 1 determines the placement of the first housing lid 32 because the first housing lid 32 sits on the radially projecting wall 45 of the safety filter element 1. If the safety filter element 1 is missing, the first housing lid 32 will slide deeper onto the central housing portion 30. This misalignment can be made noticeable by a user if, for example, the first housing lid 32 is in the position shown in FIG. 100 but is not deeper on the central housing portion 30 if the attachment means (not shown) for the first housing lid 32 could only engage.

[0334] 101 and 102 show that the safety filter element 1 may be attached to a support structure 140 that is part of the housing 5, such as part of the first housing lid 32. The safety filter element 1 is attached to the support structure 140 at its safety filter element end cap 16.

[0335] 102, the safety filter element has a ring-shaped safety filter element circumferential surface 7 having a surface section 8 arranged such that a normal vector N to the surface section 8 is oriented to point to the outside of the safety filter element 1. A sealing component 11 forming a lip seal extends along the safety filter element circumferential surface 7. A housing sealing component 12, also provided by a lip seal, seals against a support structure 140 of the housing 5.

[0336] 103 and 104 show that the safety filter element 1 according to the invention can have a safety cage 506, whereby the safety cage 506 has a safety cage interior space 514. Such an embodiment can be called a "tool catcher", since the safety filter element 1 in the design of Figs. 103 and 104 is mainly used to "filter" tools that fall into the housing 5 and prevent them from leaving the housing through the outlet opening 15. Thereby, the safety filter element prevents any object placed downstream of the safety filter element 1 from being damaged by the tool. In a variation of the design shown in Figs. 103 and 104, a safety filter medium (not shown in Figs. 103, 104) can be placed on top of the safety cage 506. This makes the design shown in Figs. 103 and 104 similar to the design shown in Figs. 82-89.

[0337] In the preferred embodiment shown in Figures 105, 133 and 134, the main (or primary) filter element, shown with pink end caps, and the safety (or secondary) filter element, shown with green end caps, are shown mounted in the air cleaner housing, shown in orange. The cover, shown as blue, also contains the clean air outlet, which connects to the turbo via a duct and is removably attached to the main air cleaner body or housing.

[0338] Two sets of seals are shown in the following embodiment in yellow. Both sets are secured to or retained by the safety element end cap. The main element has only a sealing surface and does not retain or have any seals secured to it. The first seal or set of seals on the safety prevents dirty air from passing between the safety and the cover. The second seal or set of seals prevents dirty air from passing between the safety and the main element.

[0339] A third seal or set of seals (not shown) is also possible, which would prevent dirty air from passing between the safety and the air cleaner body or cover, and which would provide an additional back-up seal.

[0340] In the embodiments shown in Figures 105, 134, and 135, the seal (e.g., a flexible or compressible member that can create a seal when pressed against a separate component) is a thermoplastic elastomer seal that is oriented outward in a wiper configuration. The seal can be any suitable sealing material and can seal in either an inward, outward, axial, or pinch configuration. The seal can be circular or non-circular and can deviate from the axial plane (e.g., have a wavy or stepped configuration).

[0341] The safety outlet, main element sealing surface, and cover can each be either circular or non-circular. For example, any of the above-mentioned components can have an irregular shape that requires a particular installation orientation (e.g., one-fold symmetry or other asymmetric shape). The asymmetry can be achieved as a result of the seal or sealing surface being non-circular, or by some axial deviation of the seal or sealing perimeter (e.g., one or more of an asymmetric wave, ripple, and step-like configuration) or both the non-circular shape and the axial deviation of the seal perimeter.

[0342] In the embodiments shown in Figures 105, 134, and 135, the media for the main element is pleated. Other media configurations for the main and / or safety elements are possible, such as fluted, corrugated, or media wrapped. The media can be cellulosic or synthetic, and may or may not have additional layers, such as support layers, liners, or other filter layers to enhance filtration, such as microfibers or nanofibers.

[0343] 105, 134, 135 are vertically aligned, they may be offset (e.g., when the circumferential outer surface of the end cap has different sized diameters at different portions along the length of the end cap). Also, while the first and second sets of seals shown in FIGS. 105, 134, 154 are shown to appear symmetrical, the first and / or second sets of seals may be asymmetrical (e.g., as a result of asymmetries in the safety outlet, main element sealing surface, and / or cover).

[0344] Although preferred embodiments and implementations of the present disclosure have been described, modifications and equivalents of the disclosed concepts may readily occur to those skilled in the art, however, such modifications and equivalents are intended to be included within the scope of the claims appended hereto.

[0345] Figures 106 to 122 show a further embodiment of a filter assembly according to the invention, whereby like reference numbers describe like parts as in the above-described embodiment. Figures 116 to 119 show a sequence for how the main filter element of a filter assembly according to the invention can be mounted.

[0346] 123-133 show a further embodiment of a filter assembly according to the present invention whereby like reference numbers describe like parts as in the above-described embodiment.

Claims

1. 1. A safety filter element suitable for use in a filter assembly, comprising: The safety filter element extends along an axis (A); a safety filter media, whereby said safety filter media at least partially encloses a safety filter media interior space; at least one safety filter element end cap, whereby said at least one safety filter element end cap has an outlet opening that communicates with said safety filter media interior space; the at least one safety filter element end cap includes a safety filter element circumferential support structure, the safety filter element circumferential support structure being a safety filter element circumferential surface, whereby a sealing component is disposed on and extends along the safety filter element circumferential support surface; whereby said at least one safety filter element end cap additionally includes a housing sealing component; the safety filter element circumferential support surface defines a contour shape having one-fold rotational symmetry; Safety filter element.

2. A safety filter element (1) as described in claim 1, wherein the safety filter element circumferential support structure is a safety filter element circumferential surface (7) including several surface sections (8, 9, 10, 110), whereby at least one of the surface sections (8, 9, 10, 110) is positioned such that a normal vector to the surface section (8, 9, 10, 110) is oriented (N), (a) along an axis (A), or (b) parallel to the axis (A), or (c) pointing outside the safety filter element (1).

3. The several surface sections making up the safety filter element circumferential surface are (a) arranged in the same plane, such that the safety filter element circumferential surface is arranged in said plane, or (b) designed together to form the outer surface of a cone, such that the safety filter element circumferential surface is designed to form the outer surface of a cone, or (c) designed together to form the outer surface of a cylinder, such that the safety filter element circumferential surface is designed to form the outer surface of a cylinder. The safety filter element of claim 2 .

4. A first surface section belonging to the several surface sections constituting the safety filter element circumferential surface is (1) designed to be disposed in a plane such that at least a portion of the safety filter element circumferential surface constituted by the first surface section is disposed in the plane, or (2) designed to form a section of the outer surface of a cone such that at least a portion of the safety filter element circumferential surface constituted by the first surface section is designed to form a section of the outer surface of a cone, or (3) designed to form a section of the outer surface of a cylinder such that at least a portion of the safety filter element circumferential surface constituted by the first surface section is designed to form a section of the outer surface of a cylinder, and second surface sections of the several surface sections constituting the safety filter element circumferential surface are (1) located in different planes, or (2) designed to form different conical exterior sections, or (3) designed to form different cylindrical exterior sections; The safety filter element of claim 2 .

5. A safety filter element as described in claim 1, wherein the sealing component (11) and / or the housing sealing component (12) are lip seals.

6. A filter system comprising the safety filter element of claim 1 and a main filter element (2) comprising a main filter medium (17), the main filter media (17) has a main filter media interior space, whereby the safety filter media (6) is at least partially disposed inside the main filter media interior space (18); the main filter element has a main filter element circumferential surface whereby the sealing component of the safety filter element is in sealing contact with the main filter element circumferential surface; Filter system.

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