Filter element, air filter assembly, and method of use and assembly

Abstract

The present invention discloses air filter assemblies, components, and features. The features can be used to provide: An air filter assembly (1) includes a housing (2) and a cover (50), in which a primary filter element (100) and a secondary filter element (200) having a media pack and a sealing structure surrounding the media pack can be installed. The filter element can include an open end cap having an axially offset sealing structure and a plurality of axially extending slots for engaging ribs on the housing. The filter element can further include an extension that projects fully or partially from the open end cap and includes axially extending slots. The filter element can further include a guide that projects from the extension for providing a low friction surface against the housing during installation and for allowing an axial force applied by an installer during installation to be converted into a rotational force for rotating the filter element.

Description

[0001] Related Applications

[0002] This application is filed as a PCT international application on November 3, 2017, and claims priority to U.S. Provisional Patent Application Serial No. 62 / 417,722, filed on November 4, 2016, the patent document of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present invention relates to filter assemblies, such as air filter assemblies, their components and features, and methods of assembly and use. The filter assembly includes a housing having a removable and replaceable filter element therein. Various features of the filter housing and / or the filter element are described, which may provide advantages. Methods of assembly and use are described. Background Art

[0004] Air or other gas filtration is required in many systems. Common applications are filtering the intake air of internal combustion engines. Another is the filtration of crankcase ventilation filter assemblies. Generally, the system includes a filter assembly having a serviceable filter element therein. After being used for a period of time, the filter medium in the filter housing needs to be maintained / repaired by cleaning or complete replacement. Generally, for an air filter or a crankcase ventilation filter assembly used with an internal combustion engine, such as on a vehicle, the filter medium is contained in a removable and replaceable and thus serviceable component, usually referred to as a filter (element) or filter element. The filter element is arranged to be removably sealed within the air filter during use. It is desired to improve the filter structure related to assembly, serviceability, and use. The filter element can be arranged as a primary filter element or a secondary filter element. The air filter assembly can contain only the primary filter element or both the primary filter element and the secondary filter element. Summary of the Invention

[0005] Features and components of a filter assembly (such as an air filter assembly or a crankcase ventilation filter assembly) are described. Methods of assembly and use are also described. The filter assembly generally includes a housing having a filter element removably disposed therein.

[0006] Example assemblies include a first filter element and a second filter element, wherein the first filter element has a first sealing structure arranged to seal against a part of the housing and having a sealing surface, and wherein the second filter element has a second sealing structure arranged to seal against the sealing surface of the second filter element. In one embodiment, the first sealing structure is an outwardly directed radial seal, while the second sealing structure is an inwardly directed radial seal.

[0007] Each of the first and second filter cartridges may be provided with features for ensuring proper alignment of the cartridge relative to the housing and the outlet cover. Due to each of the first and second filter cartridges being provided with axially offset sealing structures, proper alignment facilitates ensuring proper sealing. The filter cartridge may be provided with an extension that projects from the open end cap of the cartridge. In one example, the extension is provided with an axially extending radially facing recess that is received by a corresponding rib associated with the outlet cover. In one example, the extension is provided with a guide that provides a low friction surface with the outlet cover, which enables the filter cartridge to self-align. In one example, both of these features are provided. Each of these features provides tactile feedback to the installer, allowing the user to sense whether the filter cartridge is properly aligned and inserted relative to the housing outlet cover.

[0008] There is no particular requirement that the air filter assembly, its components, or its features include all of the details characterized herein in order to obtain some of the advantages in accordance with the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a perspective view of an air filter assembly in accordance with the present invention, the air filter assembly including a housing assembly in which at least one filter cartridge is installed.

[0010] Figure 2 is Figure 1 a top view of the air filter assembly shown in

[0011] Figure 3 is Figure 1 an exploded view of the air filter assembly shown in , where a first filter cartridge, a second filter cartridge, and an outlet cover are shown for use in combination with the housing assembly.

[0012] Figure 4 is Figure 3 a perspective view of the first filter cartridge shown in

[0013] Figure 5 is Figure 4 a side view of the first filter cartridge shown in

[0014] Figure 6 is Figure 4 a top view of the first filter cartridge shown in

[0015] Figure 7 is Figure 4 a cross-sectional side view of the first filter cartridge shown in

[0016] Figure 8 is a perspective view of an annular member that is Figure 4 a part of the first filter cartridge shown in

[0017] Figure 9 is Figure 8 a top view of the annular member shown in

[0018] Figure 10 is Figure 8 a side view of the annular member shown in

[0019] Figure 11 is Figure 3 a perspective view of a part of the second filter element shown in

[0020] Figure 12 is Figure 11 a side view of the second filter element shown in

[0021] Figure 13 is Figure 11 a top view of the second filter element shown in

[0022] Figure 14 is Figure 11 a cross-sectional side view of the second filter element shown in

[0023] Figure 15 is a perspective view of the annular member which is Figure 11 a part of the second filter element shown in

[0024] Figure 16 is Figure 15 a top view of the annular member shown in

[0025] Figure 17 is Figure 15 a side view of the annular member shown in

[0026] Figure 18 is Figure 3 a perspective view of the outlet cap shown in

[0027] Figure 19 is Figure 18 a cross-sectional side view of the outlet cap shown in

[0028] Figure 20 is Figure 18 a bottom view of the outlet cap shown in

[0029] Figure 21 is of the first filter element, the second filter element and the outlet cap in an assembled state Figure 3 a cutaway perspective view of the portion shown in

[0030] Figure 22 is Figure 21 a cross-sectional top view of the assembly shown in

[0031] Figure 23 is Figure 22 a cross-sectional side view of the components shown in

[0032] Figure 24 is Figure 3 a cross-sectional side view of the first filter element shown in

[0033] Figure 25 is Figure 4 a cross-sectional side view of the first filter element further inserted into the outlet cover shown in

[0034] Figure 26 is Figure 4 a cross-sectional side view of the first filter element fully inserted into the outlet cover shown in

[0035] Figure 27 is usable for Figure 1 a perspective view of a second example of the first filter element within the air filter assembly shown in

[0036] Figure 28 is Figure 27 a cross-sectional side view of the first filter element shown in

[0037] Figure 29 is usable for Figure 1 a perspective view of a third example of the first filter element within the air filter assembly shown in

[0038] Figure 30 is Figure 29 a cross-sectional side view of the first filter element shown in

[0039] Figure 31 is usable for Figure 1 a perspective view of a second example of the second filter element within the air filter assembly shown in

[0040] Figure 32 is Figure 31 a cross-sectional side view of the second filter element shown in

[0041] Figure 33 is usable for Figure 1 a perspective view of a third example of the second filter element within the air filter assembly shown in

[0042] Figure 34 is Figure 33 a cross-sectional side view of the second filter element shown in

[0043] Figure 35 is usable for Figure 1 the air filter assembly and Figure 27, 28 Perspective view of a second example of an outlet cover of the filter element shown in 31 and 32.

[0044] Figure 36 is Figure 35 Cross-sectional side view of the outlet cover shown in.

[0045] Figure 37 is Figure 35 Bottom view of the outlet cover shown in.

[0046] Figure 38 is in the assembled state and is a cutaway partial perspective view of the first filter element, the second filter element, and the outlet cover shown respectively in Figure 27 , 31 and 35.

[0047] Figure 39 is Figure 38 Cross-sectional top view of the assembly shown in.

[0048] Figure 40 is Figure 38 Cross-sectional side view of the assembly shown in.

[0049] Figure 41 is usable for Figure 1 Perspective view of a third example of the first filter element within the air filter assembly shown in.

[0050] Figure 42 is Figure 41 Top view of the filter element shown in.

[0051] Figure 43 is Figure 41 Side view of the filter element shown in.

[0052] Figure 44 is Figure 41 Cross-sectional side view of the first filter element shown in.

[0053] Figure 45 is usable for Figure 1 the air filter assembly and Figure 27 , 28 , 31, 32, and 41. Perspective view of a third example of the outlet cover of the filter element shown in.

[0054] Figure 46 is Figure 45 Enlarged view of a part of the outlet cover shown in.

[0055] Figure 47 is Figure 45 Bottom view of the outlet cover shown in.

[0056] Figure 48 is Figure 45 a cross-sectional side view of the outlet cover shown in Figure 41 with a filter element installed therein.

[0057] Figure 49 is Figure 45 an enlarged view of a portion of the outlet cover shown in

[0058] Figure 50 is usable for Figure 1 a cross-sectional view of a fourth example of a first filter element within the air filter assembly shown in

[0059] Figure 51 is Figure 50 a cross-sectional view of the filter element shown in

[0060] Figure 52 is Figure 50 a partial cross-sectional view of the filter element shown in

[0061] Figure 53 is Figure 27 、 28 、31, 32 and 41, showing a schematic plan view of the sealed side of the open end cap of any of the filter elements shown.

[0062] Figure 54 is a schematic plan view of an alternative open end cap design having features usable with any of the filter elements herein.

[0063] Figure 55 is a schematic plan view of an alternative open end cap design having features usable with any of the filter elements herein.

[0064] Figure 56 is a schematic plan view of an alternative open end cap design having features usable with any of the filter elements herein.

[0065] Figure 57 is a schematic plan view of an alternative open end cap design having features usable with any of the filter elements herein.

[0066] Figure 58 is a schematic plan view of an alternative open end cap design having features usable with any of the filter elements herein.

[0067] Figure 59 is a schematic plan view of an alternative open end cap design having features usable with any of the filter elements herein. Detailed Description

[0068] Here, exemplary filter assemblies, filter cartridges, their features, and components are described and illustrated. Various specific features and components are characterized in detail. Many can be applied to provide advantages. However, there is no particular requirement to apply the various different features and components in all assemblies having all the described features and characteristics in order to provide some of the benefits according to the present invention.

[0069] It should be noted that a number of embodiments are shown and described. The embodiments are not meant to be exclusive with respect to the features shown. That is, if desired, selected features of one embodiment can be applied to one or more other embodiments in order to gain an advantage. In many examples, the filter assembly shown is an air filter assembly, for example, for filtering the intake air of an internal combustion engine. However, the concepts disclosed are not limited in any way to such applications and can be applied to a variety of different applications, such as crankcase ventilation. The filter assemblies disclosed are generally "gas filter assemblies" since the carrier stage being filtered is a gas (air or crankcase ventilation gas). Although the techniques described herein are generally for gas filtration applications, they can be used to filter other materials, such as liquids, if desired.

[0070] I. Filter Assembly - Overview

[0071] Figure 1 Reference numeral 1 generally denotes a filter assembly, such as an air filter or air filter assembly or structure according to the present invention. The filter assembly (an air filter assembly in the example) 1 includes a housing 2. The housing 2 defines sidewalls 2s and includes: a first body or housing portion 3; and, a second body portion or access cover 4. In the example shown, the access cover 4 is removably fixed to the first body portion 3, but alternatives are possible. And, although alternatives are possible, for the example shown, the connection of the cover portion 4 to the body portion 3 is achieved by a latch structure 5 that includes an over-center latch. Alternatively, the cover portion 4 can be fixed to the body portion 3 by a twist-lock structure. An exemplary twist-lock structure is shown in U.S. Application No. 15 / 192,272, filed on June 24, 2016, the patent document of which is incorporated herein by reference. The cover portion 4 can be fixed to the body portion 3 by the latch 5 (e.g., an over-center latch).

[0072] Generally, the air (gas) filter 1 includes an air (gas) inlet structure 7. In the illustrated example, the air inlet structure 7 is an inlet pipe denoted as 7t on the main body portion 3. The specific inlet pipe 7t shown is arranged as a lateral tangential inlet, i.e., the air flow is directed tangentially against the inner wall of the housing 2 rather than being directed directly towards the central axis X of the housing. Alternative inlet structures, positions, and directions are possible. However, due to reasons discussed below, the tangential inlet structure shown is convenient and advantageous.

[0073] At 8, a dust / water injector structure is shown on the housing 2, including a pipe 9. In the illustrated example, the pipe 9 forms part of the access cover 4, although alternatives are possible. The pipe 9 is covered by an exhaust valve structure 10, which in the illustrated example includes a duckbill valve of a type widely used with air filters, see for example WO 2006 / 06241A1; U.S.6,419,718B1; and U.S.8,864,866, which are hereby incorporated by reference. Alternative exhaust valve structures may be used.

[0074] At 50, an outlet cover having an outlet pipe or flow pipe 52 is shown, provided as part of the housing 2 on the remainder of the housing main body portion 3. The outlet cover 50 may be integrally formed with the housing body 3 but is shown as a separate component attached to the housing body 3 via fasteners. As shown, the outlet structure or pipe 52 extends into the interior of the housing such that the filter element can seal against the outlet structure 52. The outlet structure also extends towards the exterior of the housing. In the illustrated embodiment, the inner and outer extension portions of the outlet structure 52 are discontinuous as they have different diameters. However, these features integrally formed with the outlet cover provide a continuous passage from the interior to the exterior of the housing.

[0075] In operation, the air (gas) to be filtered enters the air filter assembly through the inlet pipe 7t. Eventually, the air passes through the filter medium of the filter element structure disposed within the interior 2i of the housing 2. After passing through the medium of the air filter element, the filtered air is directed to leave the housing through the outlet pipe 52. From the outlet pipe 52, the filtered air is directed to a downstream device, such as the inlet of a turbine system or an engine system.

[0076] The specific air filter (filter) assembly 1 shown includes an optional pre-filter stage. The pre-filter stage is provided in part by directing the air from the inlet pipe 7t tangentially into the interior 2i of the housing 2. The air is then directed in a cyclonic pattern around the interior of the assembly 1. This will help to drive a portion of any water or dust particles contained in the air flow against the inner surface of the side wall 2s. The material separated from the air flow will ultimately migrate to and enter the pipe 9 and be ejected from the pipe 9 through the valve 10.

[0077] The specific air filter assembly 1 shown is arranged such that it can be installed in various orientations, for example, such that the central axis X is vertically oriented, or alternatively such that the central axis X is horizontally oriented. This is facilitated by having the outlet tube 9 point downward.

[0078] The housing body portion 3 may include a mounting pad structure. The mounting pad structure may be integrally formed with the remainder of the housing 2, or it may be a separate component. The mounting pad structure is used to help secure the housing 2 in place on the equipment that will use the air filter 1. By having the mounting pad structure provided on the housing portion 3, the housing portion 3 can be held in place on the equipment by bolts or other systems during servicing / maintenance, where the access cover 4 is removably secured to the body portion 3 to facilitate maintenance / repair. An exemplary mounting pad structure that can be used as part of the housing portion 3 is disclosed in U.S. 8,864,866, the disclosure of which is incorporated herein by reference.

[0079] As described so far, the air filter assembly is similar to many existing air filter assemblies, including those shown and described in WO2006 / 06241A1; WO 2009014988; U.S. 6,419,718 B1; and U.S. 8,864,866, the disclosures of which are incorporated herein by reference.

[0080] Now referring to Figure 3 and Figure 4 which shows Figure 1 and 2 the housing assembly in combination with a first example of a serviceable internal filter component that can be disposed within the housing 2. In the exploded view of Figure 3 the first filter element 100 and the second filter element 200 are visible and shown as being locatable within the interior 2i of the housing. Each of the filter elements 100, 200 is arranged to form a seal with the outlet cover 50. Alternative configurations of the first filter element 100 are shown in Figures 27 - 28 (filter element 100’) and Figures 29 - 30 (filter element 100”). Alternative configurations of the second filter element 200 are shown in Figures 31 - 32 (filter element 200’) and Figures 33 - 34 (filter element 200”). Alternative configurations of the outlet cover 50 are shown in Figures 35 - 37 . The filter elements 100’, 200’ can be used together with the outlet cover 50’ within the housing 2 shown in Figures 1 - 3 . Similarly, the filter elements 100” and 200” can be used together within the housing 2 shown in Figures 1 - 3 . Each of these variations will be discussed in more detail below.

[0081] The filter element 100 can be referred to as the main filter element or main filter component, and the filter element 200 can be referred to as the secondary or safety filter element or secondary or safety filter component. Generally, the filter element 100 is a serviceable part that includes an extension of the filter medium 102 through which the air to be filtered passes before it can leave the assembly 1. Similarly, the filter element 200 is a serviceable part that includes an extension of the filter medium 202 through which the air to be filtered also passes before leaving the assembly 1. The term "serviceable part", as used herein in connection with the filter elements 100, 200, means that the filter elements 100, 200 are removable and replaceable within the air filter assembly 1. Thus, when the media 102, 202 of the filter elements 100, 200 become clogged during use, the filter element 100 and / or the filter element 200 can be removed and refurbished or replaced.

[0082] In one aspect, the housing 2 can include an optional but advantageous shroud structure that surrounds a selected portion of the filter element 100. The shroud structure can be used to inhibit dust and other materials carried by the inlet air from directly impinging on the media 102 until the air has passed through the shroud at least partially by cyclonic motion and in a direction toward the access cover 4. The shroud helps facilitate the removal of dust and other materials into the dust ejector structure 8. The use of a shroud structure is common in many air filter configurations, see for example, WO 2006 / 06241A1; WO 2009 / 014988; USSN 61 / 446,653; USSN61 / 473,296; U.S.6,419,718B1; and U.S.8,864,866, the disclosures of which are hereby incorporated by reference herein. Similar features and principles can be used here.

[0083] It should be noted that the use of the shroud structure and the dust ejector structure 8 is consistent with many applications where a "two-stage" or "dual-stage" air (gas) filter is required, having a first pre-filter stage to separate water and larger particles from the air before it enters the filter element 100 (the second stage). However, such features are generally optional, and many of the principles of the present invention can be applied to air filters that do not have such a two-stage configuration or pre-filter stage.

[0084] Downstream of the filter element 100 is the secondary filter element 200 so that the air passes through the filter element 100 and the filter element 200 before exiting via the air outlet 52. It should be understood that the air filter assembly 1 can be used with the filter element 100 alone, the filter element 200 alone, or both the filter element 100 and the filter element 200 together, as Figure 2 shown.

[0085] II. Filter Assembly - Primary Filter Cartridges 100, 100', 100'', 100''', 300

[0086] As described above, many of the features previously identified and discussed in connection with Figures 1 - 3 the general air filter structure (filter assembly) and operation are well-known features and have been used in various systems in their present form.

[0087] The filter cartridge 100 may be referred to as the primary filter cartridge or primary filter element, and the filter cartridge 200 may be referred to as the secondary or safety filter cartridge or secondary or safety element. Generally, for convenience, the primary filter cartridge or primary filter element and the secondary or safety filter cartridge or secondary or safety filter element may be referred to as filter cartridges or filter elements. Based on the context, it should be obvious whether the primary or secondary filter cartridge is being referred to.

[0088] Generally, in addition, the filter cartridges 100 and 200 are serviceable components. That is, they can be removed and replaced during the service life of the air filter 1. A releasable seal is required between the filter cartridge 100 and a portion of the outlet cover 50 and between the filter cartridge 200 and the outlet cover to allow the filter cartridges to be serviceable components and to ensure that unfiltered air does not bypass the filter cartridge 100 and / or the filter cartridge 200 and enter the outlet pipe 52, as this could damage the engine.

[0089] The filter cartridge 100 generally includes a filter medium 102 extending between first and second opposing media ends 104 and 106. The first media end 104 is engaged by a first end cap or end member 108. The second media end 106 is engaged by a second end cap or end member 110. Thus, the medium 102 extends between the opposing end caps (or end members) 108, 110.

[0090] Although alternatives to the selected techniques described herein are possible, for the example shown, the filter medium 102 is arranged to surround the filter interior 102i of the opening, generally about the central axis X of the air filter 1 and the filter element 100. The medium 102 can be a pleated medium, although alternatives are possible. If desired, the medium 102 can be arranged in a cylindrical form as shown, although alternatives are possible. For example, the medium 102 can extend somewhat conically between opposite ends 104, 106. Additionally, the medium 102 can be arranged to have a non-circular inner perimeter and / or outer perimeter; for example, an oval or other cross-sectional configuration is possible. Further, the main filter element 100 can be provided with a screen or support structure 102s extending from the first end 104 to the second end 106 to assist in supporting the filter medium 102 while allowing gas (air) to pass therethrough. The filter medium 102 can be embedded in the first and second end caps 108 and 110. Additionally, the screen or support structure 102s for the filter medium 102 can be embedded in the first and second end caps 108 and 110.

[0091] Although alternatives to the selected techniques described herein are possible, the second end member or end cap 110 is generally a closed end member or end cap that extends completely across the medium 102 at the second end 106, closing the end 106 of the medium 102 and the filter interior 102i. That is, for the example shown, the end member or end cap 110 is a closed end member or end cap, i.e., the end cap has no holes therethrough that communicate with the open filter interior 102i.

[0092] On the other hand, the first end member or end cap 108 is an open end member or end cap. That is, it surrounds and defines a central hole 112 that communicates with the medium (in the example via the open filter interior 102i). In normal use, the hole 112 is an outlet hole for the airflow from the medium (such as the open filter interior 102i) for the filtered air. In an alternative application (where the airflow is reversed during filtration), the hole 112 can be an inlet hole. Generally, it is an airflow hole.

[0093] For the example shown, the first end cap 108 extends completely across all of the medium 102 of the filter element 100 from the outer perimeter 108a to the inner perimeter 108b. The first end cap 108 generally has only one central hole 112 therethrough.

[0094] Further, when the access cover 4 is removed from the housing body portion 3, an access opening is provided to the interior 2i for installing or removing the filter element 100. Then, the filter element 100 needs to be removably sealed to the outlet cover 50 sufficiently to prevent unfiltered air from flowing into the outlet pipe 52. To this end, the filter element 100 is provided with a main (or housing) seal structure 114.

[0095] Regarding the first housing seal or main seal structure 114, and other features of the first end cap 108, please note Figures 6 - 7 and 18 - 20. The main seal structure 114 can be seen as defining a radially oriented seal or sealing surface 114s, which is guided to engage the surface 52s1 of the outlet cap flow tube 52 for a releasable seal. Thus, when the main filter element 100 is installed in the filter assembly 1, the main seal structure 114 forms an inwardly oriented radial seal with the outlet tube 52.

[0096] Still referring to Figure 7 , it should be understood that the surface 114s of the main seal structure 114 that forms a seal with the outlet tube 52 is generally a radially oriented surface. Thus, the main seal structure 114 can be referred to as a radially oriented seal. In this context, "radially" means that the seal or sealing surface (and the compression of the sealing surface during sealing) is generally oriented towards or away from (i.e., around) the central axis X. The specific surface 114s shown in the example is radially inwardly oriented relative to the central axis X, so the seal structure 114 can be characterized as "radially inwardly oriented". However, it should be noted that a radially outwardly oriented seal can be used with the same principle according to the present invention.

[0097] It should be noted that in the example shown, the housing seal structure 114 includes a part of the end cap 108. More generally, the housing seal structure 114 is mounted on the filter element and is arranged to releasably seal to the housing component or the outlet tube 52, regardless of whether the specific housing seal structure includes a part of the end component.

[0098] The preferred and advantageous housing seal structures described herein are generally "non - clamping" or "no - clamping" housing seal structures. This means that they are established when the filter element is inserted into the housing without the need to tighten some type of clamp or connector.

[0099] In one aspect, the end cap 108 and the seal structure 114 can be configured such that the maximum radial compression of the end member (end cap) material in the region between the surface 114s and the support medium 102 or support 102s is at least 10%, typically at least 15%, preferably not more than about 35%, and typically the maximum compression is in the range of about 20 - 30%, including the end values. To this end, a seal support can be provided within the end cap 108. In one aspect, the seal structure 114 has a stepped profile such that it has a smaller diameter closer to the closed end cap 110 relative to the diameter furthest from the closed end cap 110. This stepped profile facilitates easier acceptance onto the outlet tube 52 and also allows for progressive compression of the seal structure 114 during installation. Although a stepped profile is shown, many other profiles can be used, for example, profiles having cross-sectional shapes such as rectangular, oval, geometric, chamfered, and / or circular.

[0100] In one aspect, the seal structure 114 on the end cap is also provided with an axially offset profile, wherein a first portion 114a of the seal structure 114 is disposed at a first axial position and a second portion 114b of the seal structure 114 is disposed at a second axial position. The first and second portions 114a, 114b, separated by a height h2, are interconnected by an inclined intermediate portion 114c. In one aspect, the edge of the first portion 114a furthest from the closed end cap 110 extends along a radial plane 130, while the edge of the second portion 114b closest to the closed end cap 110 extends along a radial plane 132. As Figure 7 most readily seen, the radial planes 130, 132 extend orthogonally with respect to the longitudinal axis X and are separated by a height h3. In the example shown, three first portions 114a and three second portions 114b are provided with six intermediate portions 114c therebetween. More or fewer portions 114a, 114b, 114c can be provided to obtain the desired axially offset pattern.

[0101] In one aspect, the end cap 108 can be characterized as having a body 116, and a plurality of discrete, circumferentially spaced extensions 118 can extend axially away from the body 116. In the example shown, the extensions 118 are radially aligned with the second portion 114b of the seal structure. However, the extensions 118 can be oriented to be aligned with the first portion 114a and / or the intermediate portion 114c. In the example shown, three extensions 118 of similar size and construction are shown at equal spacing from each other. However, more or fewer extensions 118 can be provided. The extensions 118 are also not required to have the same shape, size, or spacing / pitch. Instead, the filter cartridge 100 can be provided with extensions 118 of different sizes or arrangements.

[0102] Each of the extensions 118 has radially inward and outward sides 118a, 118b that extend from a proximal end 118c to a distal end 118d (to a height h1) and extend between first and second sides 118e, 118f (width w1). As shown, the first and second sides 118e, 118f are inclined inwardly toward each other in a direction from the proximal end 118c toward the distal end 118d. In the example shown, the sides 118e, 118f are set at an angle of approximately 10 degrees with respect to the longitudinal axis X such that the angle defined between the sides 118e, 118f is approximately 20 degrees. In this example, the ratio between the height h1 and the width w1 is approximately 0.8. Other dimensions and configurations are possible. For example, the sides 118e, 118f may be parallel to the longitudinal axis X such that they extend perpendicularly from the body 116. When the filter element 100 is fully installed into the housing 2 and reaches the outlet cap 50, the extensions 118 are received within a recess or notch 56 of the outlet cap 50. Once in this position, the sides 118e, 118f contact the sidewalls 56a, 56b of the recess to prevent rotation of the filter element 100 relative to the outlet cap 50. In the example shown, the contact between the sides 118e, 118f and the sidewalls 56a, 56b occurs only along a portion of the sides 118e, 118f. In other examples, the sidewalls 56a, 56b may be set parallel to the sides 118e, 118f to achieve a greater contact length.

[0103] Each of the extensions 118 is provided with one or more rotational alignment features that enable the filter element 100 to be properly aligned relative to the outlet cap 50 and within the housing 2. In the example shown, each extension is provided with an optional axial slot or recess 120 that extends from a distal end 120a near the distal end 118d of the extension to a proximal end 120b that is located within the internal space 102i near the second portion 114b of the seal structure and adjacent to the medium 102. Thus, the axially offset first portion 114a of the seal structure is located between the slots or recesses 120, while the second portion 114b is located axially below the slots or recesses 120. In an alternative configuration, the slots or recesses 120 are not aligned with the second portion 114b. However, in the example described, the length of the slots or recesses 120 will be limited by the axial position of the portion of the seal structure 114 that is aligned with the slots or recesses 120. The configuration shown allows the slots or recesses 120 to have the maximum possible length.

[0104] In the example shown, the axial recess 120 has a width and a depth that each taper or narrow in a direction from the distal end 120a to the proximal end 120b. As Figures 18 - 20As shown, the outlet cap 50 is provided with axially extending ribs 54 which are similarly tapered from a narrow distal end 54a to a wider base end 54b to form a complementary shape with the axial groove or recess 120. Thus, when the filter element 100 is initially inserted into the outlet cap 50, the narrow end 54a of each rib 54 is received by the relatively wider receiving area of the distal end 120a of the recess 120. This arrangement allows the filter element 100 to be inserted towards the outlet cap 50 and then rotated until the ribs 54 are aligned with the groove or recess 120, at which point the filter element 100 is further lowered into place until the ribs 54 are fully received in the groove or recess 120 and the extension 118 is received in the recess 56 of the outlet cap 50. Once fully inserted, the ribs 54 fit tightly against the groove or recess 120 to hold the filter element 100 firmly in the desired alignment, where the sealing structure 114 seals against the outer surface 52s1 of the outlet pipe 52.

[0105] Another rotational alignment feature associated with the filter element 100 is provided by the guides 122 which project from each extension 118. The guides 122 have an arcuate shape generally following the shape of the distal end 118d of the extension 118. However, the guides 122 are formed of a harder plastic, such as ABS (acrylonitrile - butadiene - styrene) or PP (polypropylene plastic), compared to the polyurethane extensions 118. Thus, the guides 122 can be referred to as low - friction components as they have a lower frictional resistance relative to the hard plastic housing. In some cases, the low - friction component does not need to have a greater hardness than the extension, as long as the material of the low - friction component serves to reduce the friction to a level below that existing between the housing and the extension. In the case where the extension is made of a harder plastic, the guides 122 can contribute to the stiffness of the extension 118. In one aspect, the desired stiffness of the extension 118 (and thus the tactile feedback to the installer) can be achieved by designing the shape and dimensions of the polyurethane forming the extension and the shape and dimensions of the portion of the guide 122 embedded within the polyurethane. In some examples, there are fewer guides provided than the total number of extensions. For example, the filter element may be provided with six extensions, three of which include guides.

[0106] During the installation of the filter element 100 into the outlet cap 50, when the extensions 118 are not perfectly aligned with the recess or notch 56, the guides 122 will first contact the inclined walls 56c or 56d adjacent to the recess 56. The inclined walls 56c and 56d are interconnected by a curved or rounded portion 56e to allow the guides 122 to be smoothly guided in either direction towards the walls 56c or 56d. Since the outlet cap 50 is also formed of a harder plastic, there is relatively little friction between the inclined walls 56c, 56d and the guides 122.

[0107] Figure 24Shows a situation where a filter cartridge 200 with a similar guide is initially inserted into the outlet cap 50 such that the guide contacts the inclined wall. Figure 25 Shows a further inserted filter cartridge where the guide slides along the inclined wall such that the filter cartridge extension gradually aligns with the recess. Due to the low friction relationship between the inclined walls 56c, 56d and the hard plastic (e.g., ABS, PP) guide surface 122 and the hard plastic (e.g., ABS, PP) walls 56c, 56d, as the installer applies a force to the filter cartridge in the direction towards the open end cap 108, the filter cartridge 100 will automatically start to rotate. Preliminary tests by the inventors have shown that when the portion of the extension 118 in contact with the walls 56c, 56d is formed of a relatively soft material (such as polyurethane), this type of automatic rotation or translation force is difficult to achieve, if at all. Thus, the addition of the hard plastic guide 122 is included in the end cap 108 such that the axial force provided by the installer can be converted into a rotational force.

[0108] Automatic rotation of the filter cartridge 100 will occur until one of the sides 118e, 118f of each extension 118 contacts the rib 54. At this point, the rib 54 provides resistance to the rotation of the filter cartridge 100, and then the installer must apply an additional axial force and / or start actively rotating the filter cartridge with a rotational force, depending on the inclined configuration of the walls 56c, 56d and the configuration of the guide 122. It is noted that as the walls approach the recess or notch 56, the inclination of the walls 56c, 56d increases at the radius (range) or curved portion 56e, thereby increasing the amount of force converted from the axial direction to the rotational direction.

[0109] The formed extensions 118 are flexible enough such that when the filter cartridge 100 is subjected to sufficient rotational force, they will deflect radially outwards over the rib 54. As Figure 18 most readily seen, the rib 54 is provided with a double - conical profile (i.e., the rib narrows in the direction from the recess 56 towards the end 52b and radially outwards from the sealing surface 52s1) such that the extensions 118 can initially be biased towards the rib. As the filter cartridge 100 is forced to rotate, the rib 54 will eventually snap into the slot or recess 120 of the extension 118, at which point the extension 118 largely returns to its initial position. The snapping action that occurs when the rib 54 snaps into the slot or recess 120 provides tactile feedback to the installer, thereby confirming to the installer that the filter cartridge 100 is fully installed. Once the filter cartridge 100 has rotated to this point, the extensions 118 can fully drop into the recess or notch 56, as Figure 26As shown, depending on how the installer applies the force, the extension 118 can fall into the recess during rotation (if an axial force and a rotational force are applied simultaneously) or cause the rib 54 to be received within the recess or notch 56 after the rotational force is applied. Of course, if the installer initially aligns the groove or recess 120 with the rib 54, the filter element 100 can simply drop directly into the housing and be pressed into the fully installed position without rotation. Figure 26 A fully installed filter element is shown, where the extension 118 has fallen into the recess. In some embodiments, the recess or notch 56 and the extension 118 are formed such that once the filter element 100 is fully installed, the guide 122 no longer contacts the housing. This can be achieved by providing the recess or notch 56 with a greater depth such that the extension 118 provides all contact with the outlet cover 50 via the side walls 56a, 56b.

[0110] See Figures 8 to 10 , it can be seen that the guide 122 is formed by an annular structure 124, where the guide 122 extends upward from the base ring 126. As is most easily seen in Figure 7 , the annular structure 124 is embedded within the polyurethane material of the end cap 108 such that only the distal end 122a extends past the extension 118. In the illustrated embodiment, the guide 122 is also provided with support ribs 122b that not only provide reinforcement to the guide 122 itself but also provide reinforcement to the extension 118 in which they are embedded. In an alternative example, the extension 118 can include a separate guide 122 that is separately embedded within the extension 118 or simply attached to the distal end 118d of the extension 118. In one example, the guide 122 is provided to be attached to the extension 118. The guides 122 can also be formed such that they are integrally formed with the filter element gasket 102s. In one example, the guides 122 are co-molded with the extension 118.

[0111] As Figure 27 and 28 shown, an alternative filter element 100' is shown. The filter element 100' shares many common features with the filter element 100. For these features, the description of the filter element 100 applies fully to the filter element 100' and need not be repeated here. Where similar features exist, similar reference numerals are used. Rather, the description of the filter element 100' here will be directed to the differences between the filter elements 100 and 100'.

[0112] One such difference is that no guide 122 is provided for the filter element 100'. Thus, the slot or recess 120 is responsible for ensuring the initial alignment of the extensions 118 until they are received within the recess or notch 56' of the outlet cap 50'. The extension 118' also has a slightly different shape compared to the extension 118, with a lower aspect ratio. The outlet cap 50' is shown in Figures 35 - 37 and differs from the cap 50 in that the wall 56c' is not inclined but flat. Preliminary tests have shown that in the absence of the rigid plastic guide 122, the filter element does not automatically rotate into alignment by the applied axial force because there is substantially too much friction between the polyurethane extensions and the outlet cap walls. Thus, since the guide 122 is not provided, there is no need to have the wall 56c inclined at an angle towards the recess or notch 56'. The extension 118' is also provided with a sharper sidewall angle and more material to improve the tactile feedback when the slot 120' snaps into the ribs of the outlet cap.

[0113] As Figure 29 and 30 shown, another alternative filter element 100'' is shown. The filter element 100'' shares many common features with the filter elements 100 and 100'. For these features, the description of the filter elements 100 and 100' applies fully to the filter element 100'' and need not be repeated here. Where similar features exist, similar reference numerals are used. Rather, the description of the filter element 100'' here will be directed to the differences between the filter elements. Like the filter element 100', the filter element 100'' is not provided with a guide 122. The main remaining difference is that the extension 118 is provided with a greater width and the sidewalls of the extension 118 are inclined towards each other at a greater angle. Thus, the space between the extensions 118'' is relatively smaller compared to the previous two embodiments. To accommodate the greater width of the extensions 118'' of the filter element 100'', the outlet cap recess may be provided with a similar shape.

[0114] As Figures 41 - 49As shown, another alternative filter element 100''' is shown, which can be used with an alternative outlet cap 50''. The filter element 100''' shares many common features with the filter elements 100, 100' and 100''. For these features, the descriptions of the filter elements 100 and 100' apply fully to the filter element 100''', and there is no need to repeat them here. Where there are similar features, similar reference numerals are used. The description of the filter element 100''' here will be directed to the differences between the filter elements. Like the filter elements 100' and 100'', the filter element 100''' is not provided with a guide 122. The main remaining difference is that a greater number of extensions 118''' are provided at a closer spacing compared to other embodiments. To accommodate the greater number of components 118''' and corresponding recesses 120''' of the filter element 100''', the recess of the outlet cap 50'' can be provided with a similar shape, as Figures 45 - 48 shown. In the embodiment shown, the filter element 100''' includes nine extensions 118''' and recesses 120'''. However, other numbers of extensions 118''' can be used, depending on, for example, the size and diameter of the filter element.

[0115] See Figure 46 , it can be seen that the rib structure 54'' of the outlet cap 50'' differs from the rib structures 54 and 54' in that the top surface 54a'' of the rib 54'' extends perpendicularly from the outer surface of the outlet tube 52''. The outlet cap 50'' is also shown as being provided with an additional rib structure 55'' located on the outer surface of the outlet tube 52'', such that the sealing path along the outer surface is more tightly constrained. The rib structure 55'' is shown as a pair of spaced parallel ribs, although a single rib can be provided. Similar features can be provided on the inner surface of the outlet tube 52'', where a safety filter is installed. See Figure 49 , the outlet cap 50'' is provided with an alternative rib structure 54''', in which a pair of parallel spaced ribs 54a'' are provided instead of a single rib. The features and configurations of the ribs 54'', 55'' and 54''' can serve to ensure that a proper filter element is installed by restricting the available sealing area on the outlet tube, so that an incorrect filter cannot form a seal.

[0116] See Figures 50 to 52, showing a fourth example of the first filter element 300. In this example, the seal 308 has a generally smooth surface and presents a radially oriented sealing surface 308a, rather than having axially offset sections. As shown, the seal 308 is supported by an internal support ring or member 301 around which the seal 308 can be overmolded. When installed onto the outlet tube 52", the seal 308 can be sufficiently compressed to conform to the shape around the rib 54". The support ring 301 is shown as having a raised surface 301a with axially offset sections corresponding to the location sealing path defined by the outlet tube 52". When the filter element 300 is installed onto the outlet cap 50" such that the axially offset sections of the outlet tube 52" and the raised surface 301a are aligned, the raised surface 301a serves to clamp the seal 308 into the sealing path defined on the outlet tube 52" such that a seal can be formed.

[0117] III. Filter Assembly - Second Filter Elements 200, 200’, 200”

[0118] Now refer to Figures 11 - 14 the filter element 200 shown in. The filter element 200 shares many common features with the filter element 100. For these features, the description of the filter element 100 applies fully to the filter element 200 and need not be repeated in great detail here. Where there are similar features, similar reference numerals are used within the series designation (e.g., 202 instead of 102, etc.). In addition to having smaller overall dimensions such that the filter element 200 can fit within the internal space 102i of the filter element 100, the filter element 200 has an axially offset sealing structure 214 that seals against a surface 52s2 and a recess or groove 220 in the extension 118, both the surface 52s2 and the recess or groove 220 being radially outwardly oriented and provided on the outside of the end cap 208. This is contrary to the filter element 100, where the sealing structure 114 and the groove or recess 120 are radially inwardly oriented and provided on the inside of the end cap 108. The filter element 200 is also shown as having a depth media, while the filter element 100 is shown as having a pleated media. Other than these differences, the filter element 200 has a structure generally similar to the filter element 100. Similar to the sealing structure 114, the sealing structure 214 is shown as having alternating sections, including a first part 214a, a second part 214b, and an intermediate part 214c.

[0119] The filter element 200 can be referred to as a secondary filter element or a safety filter element. During the repair / maintenance of the filter assembly 1, where the primary filter element 100 is removed and replaced with a new or refurbished filter element, the secondary filter element 200 prevents dust or debris from entering the outlet pipe 52. Additionally, in the event of a failure of the primary filter element 100, the secondary filter element 200 can be used to prevent dust or debris from entering the outlet pipe 52.

[0120] The secondary filter element 200 includes a first end 204 and a second end 206, and a filter medium 202 extending between the first end 204 and the second end 206. In the illustrated exemplary secondary filter element 200, the first end 204 includes a first end cap 208, and the second end 206 includes a second end cap 210. If desired, the secondary filter element 200 can be provided without the second end cap 210. That is, the secondary filter element 200 can be provided such that the medium extends past the second end 206. Additionally, the secondary filter element 200 can be provided with a screen or support structure 202s extending from the first end 204 to the second end 206 to assist in supporting the filter medium 202 while allowing gas (air) to pass therethrough. The filter medium 202 can be embedded in the first and second end caps 208 and 210. Additionally, the screen or support structure 202s for the filter medium 202 can be embedded in the first and second end caps 208 and 210.

[0121] The secondary filter element 200 can be configured such that the filter medium 202 is disposed around an opening of the filter interior 202i. The medium 202 can be provided as a depth medium, although alternatives are possible. For example, the medium 202 can be provided as a pleated medium or a multi-layer laminate medium, such as the medium disclosed in PCT Publication No. WO 2015 / 010085, the entire disclosure of which is incorporated herein by reference. Additionally, the medium 202 can be provided as a layer of filter medium disposed in a corrugated configuration as disclosed in PCT Publication No. WO 2015 / 010085. If desired, the medium 202 can be provided in a cylindrical form as shown, although alternatives are possible. For example, the medium 202 can extend somewhat conically between the opposing ends 204, 206. Additionally, the medium 202 can be provided with a non-circular inner perimeter and / or outer perimeter. For example, the medium can be provided with an oval, circular, or other cross-sectional configuration.

[0122] The second end cap 210 can be configured as a closed end member or end cap that extends completely across the media 202 at the second end 206, closing the second end 206 of the filter media 202 of the filter interior 202i. The second end cap 210 can include a protruding portion 210a that helps provide separation and cushioning between the secondary filter element 200 and the primary filter element 100. Additionally, the second end cap 210 can include a plurality of radially extending ridges to assist a user in gripping the secondary filter element 200 to facilitate insertion of the secondary filter element 200 into the filter assembly 1 or removal of the secondary filter element 200 from the filter assembly 1.

[0123] The second end member or end cap 210 can be characterized as a closed end member or end cap, i.e., the end cap has no holes therethrough that communicate with the open filter interior 202i. In various alternative configurations, the second end 206 can be configured without an end cap. In one variant of the secondary filter element 200 without the second end cap 210, the filter media 202 extends through the second end 206 and encapsulates the second end 206. That is, the filter media 202 can form a closure at the second end 206 to prevent unfiltered air from entering the open filter interior 202i. In an alternative, the second end 206 can be provided with a sealing structure that is mounted on a secondary filter element support structure, where the support structure includes a closed end corresponding to the second end 206 of the secondary filter element 200. The remainder of the support structure will be open to allow gas (air) to flow therethrough. However, the closed end of the support structure will engage a seal at the second end of the secondary filter element 200 to prevent unfiltered air from entering the open filter 202i.

[0124] The first end cap 208 includes a support 224 and a secondary seal 214. The support 224 that provides the guide surface 222 can be configured as a screen or part of the support structure 202s, or the support 202s can be configured as a separate component, such as a plastic preform, as Figures 15 - 17 shown. Additionally, the screen 202s extends into the end cap 208 a sufficient amount to assist in supporting the secondary seal 214 when disposed in a sealing relationship with the housing outlet cap 50. The support or screen 202s assists in supporting the secondary seal 214 when it engages the outlet tube 52. The secondary seal 214 can be referred to as a housing sealing structure or device for the secondary filter element 200. Similar to the sealing structure 114, the sealing structure 214 has a stepped profile and an axially offset profile with a slot or recess 220 extending into the profile.

[0125] Generally, the secondary seal 214 can be integrally molded with the end cap 208 and provides an outwardly directed sealing surface 214s. During operation of the filter assembly 1 with the secondary filter element 200 installed, air enters the open filter interior 202i through the filter medium 202 (after passing through medium 102), and then through the central opening space defined by the outlet tube 52.

[0126] As can be most readily seen in Figure 11 and 12 the outwardly directed groove or recess 220 extends from a distal end 220a near the distal end 218d of the extension 218 to a proximal end 220b near the second portion 214b of the sealing structure 214. As with the filter element 100, alignment of the groove or recess 220 and the second portion 214b is not required, but this arrangement increases the height of the structure.

[0127] Referring to Figures 18 - 20 , the outlet cap 50 can be seen to have a recess 58 with side walls 58a, 58b and walls 58c, 58d that slope towards the side walls 58a, 58b. Axially extending ribs 60 that extend between a distal end 60a and a proximal end 60b are also provided along the inside of the outlet tube 52. The extension 218 and the guide 222 interact with the recess and walls 58a - 58d in the same manner as previously described for the filter element 100 and the recess 56. Referring again to Figures 24 - 26 which shows the sequential installation of the filter element 200, the same principle is applicable to the filter element 100.

[0128] Alternative examples of the second filter element are shown in Figures 31 - 32 (filter element 200’) and Figures 33 - 34 (filter element 200”). The filter elements 200’ and 200” share many common features with the filter element 200. For these features, the description of the filter element 200 applies fully to the filter elements 200’ and 200”, and need not be repeated here. Where similar features exist, similar reference numerals are used. The description of the filter elements 200’, 200” will be directed to the differences between the filter elements.

[0129] One such difference is that the guide 222 is not provided for the filter element 200’. Thus, the groove or recess 220 is responsible for ensuring the initial alignment of the extension 218 until they are received within the recess 58’ of the outlet cap 50’. The extension 218’ also has a slightly different shape compared to the extension 218, with a lower aspect ratio. Figures 38 - 40 The filter elements 100’ and 200’ are shown in an assembled state relative to the outlet cap 50’.

[0130] Similar to the filter element 200', the filter element 200" is not provided with the guide member 222. The main remaining difference of the filter element 200" is that the extension member 218 is provided with a greater width, and the side walls of the extension member 218 are inclined towards each other at a greater angle. Therefore, the space between the extension members 218" is relatively small compared to the previous two embodiments. To accommodate the extension member 218" of the greater width of the filter element 200", the outlet cover recess may be provided with a similar shape.

[0131] See Figures 21 - 23 , the filter elements 100, 200 are shown in a fully installed state relative to the outlet cover 50. As can be seen from these views, the filter seal structures 114, 214 seal against the common wall 52 of the outlet cover 50, where the axially extending ribs 54, 60 are directly opposite each other. With this arrangement, the extension members 118, 218 are likewise opposite each other and are received within the relatively aligned recesses or notches 56, 58. Although this alignment is not necessarily required, the final structure of the outlet cover 50 is less complex when the outlet cover 50 accommodates the aligned filter elements 100, 200. From Figure 18 and 23 it can be most easily seen that the outlet pipe wall 52a against which the seal structures 114, 214 form a seal has an axially varying profile at the end 52b. This axially varying profile matches the axially varying profile of the seal structures 114, 214. Thus, proper sealing can only be obtained when the filter elements 100, 200 are rotated such that the seal structures 114, 214 are properly aligned and in phase with the outlet pipe wall 52a. Moreover, since the profile at the end 52b matches the profile of the seal structures 114, 214, it is not necessary to insert the seal structures 114, 214 deeply into the pipe wall 52a during installation, as would be required if the end 52b had a straight profile. This arrangement avoids the significant frictional forces that would otherwise exist if the end 52b had a straight profile, which would impede the ability of the filter elements 100, 200 to rotate automatically when the installer axially presses the filter into the housing. Alignment of the filter elements is ensured by the interaction of the extension members 118, 218 within the recesses or notches 56, 58 and / or by the interaction of the ribs 54, 60 within the grooves or recesses 120, 220. It should be noted that the filter elements 100, 200 may be provided with only the grooves or recesses 120, 220 or only the guide members 122, 222, since each of these structures serves this alignment function.

[0132] Although the specific examples of the first and second filters 100, 200 include many or all of the above features, many combinations of the features are possible, although it may result in some reduction in functionality or performance. For example, the filter element can be arranged to include an axially varying seal structure and axially extending grooves within the end cap, with or without extensions and guides. In one example, the filter element can be arranged to include extensions and axially extending grooves, with or without an axially varying seal structure and with or without guides. In one example, the filter element can be arranged to have extensions and guides, with or without an axially varying seal structure and with or without axially extending grooves. The housing and / or the outlet cap can similarly be provided with or without corresponding features that interact with the filter element structure. For example, if there are no axially extending grooves in the filter element, an outlet cap without ribs can be provided. Similarly, in the case where no extensions are provided on the filter element, an outlet cap can be provided without recesses into which the extensions extend.

[0133] IV. Filter Media and Terminology

[0134] As previously mentioned, the disclosed filter elements 100, 100’, 100”, 100”’, 200, 200’ and 200” can be provided with different numbers and configurations of extensions and recesses. See Figures 49 - 59 , a “planar” schematic view of the sealed side surfaces of various extension and recess configurations. Although shown Figures 49 - 59 using “100” and “200” series numbers in Figures 49 - 59 the features shown therein are applicable to any filter element disclosed herein.

[0135] See Figure 49 , which shows a configuration depicting the filter elements 100, 100’, 100”, 200, 200’, 200” that have been shown and described, which are provided with three extensions 118, 218 and recesses 120, 220. In such a configuration, at the second seal portions 114b, 214b, the extensions 118, 218 and the recesses 120, 220 are aligned with the seals 114, 214 such that the rotational angle a1 between the extensions 118, 218 and the recesses 120, 220 and the second seal portions 114b, 214b is zero. Figure 50 shows a configuration in which the angle a1 is increased to 180 degrees such that the extensions 118, 218 and the recesses 120, 220 are aligned with the seals 114, 214 at the first seal portions 114a, 214a. Figure 51There is shown a configuration in which the angle a1 is 90 degrees such that the extensions 118, 218 and the recesses 120, 220 are aligned with the seals 114, 214 at an intermediate position between the first seal portions 114a, 214a and the second seal portions 114b, 214b. Other offset angles between the extensions / recesses and the seal portions are possible.

[0136] See Figure 56 , there are shown exemplary end caps 108, 208 having four extensions 118 and recesses 220 instead of the three shown for other embodiments. Figure 57 There are shown exemplary end caps 108, 208 having nine extensions 118 and recesses 220. Figure 58 There is shown a configuration similar to Figure 57 the exemplary end caps 108, 208 shown, but in which the recesses 120 are provided only on a portion of the extensions 118. In the example shown, the recesses 120 are provided on every other extension 118. Other configurations are possible, such as providing the recesses 120 on one of the extensions 118. In some examples, multiple recesses 120 may be provided on the same extension 118. In some examples, the recesses 120 are offset from the center of the extension rather than being centered. Any number of appropriately sized extensions 118 and recesses 120 may be provided. Figure 59 There is shown an example of "n" extensions 118 and recesses 120. The number of extensions 118 and recesses 120 may be a function of the physical size of the filter element, as a larger diameter filter element can accommodate a greater number of extensions 118 and recesses 120. As mentioned in other sections, the spacing between the extensions 118 may also vary, and the size and shape of the extensions 118 may vary from one extension to another.

[0137] V. Filter Media and Terminology

[0138] The specific material selected for the media is a matter of choice for the selected application. When the filter assembly is an air filter, any of the various media materials currently used for air filters can be used in conjunction with the principles of the present invention.

[0139] The media pack may include only the media 102, 202, or the media may be provided with a liner and / or an outer liner before being installed into the filter cartridges 100, 200. Although other alternatives are possible, the media may be pleated, non-pleated, depth media or corrugated media. The media may be provided in various configurations, including cylindrical and conical, and having various inner and / or outer perimeters defined, such as circular or oval.

[0140] It should be noted that although the seal of the structure is sometimes characterized as "radial". However, due to the non-circular shape, some of the sealing forces are directed such that they do not particularly point towards or away from the central axis X of the filter element. Nevertheless, the seal is characterized as "radial" herein because the sealing surfaces on the general filter element and the housing are generally radially oriented, and the sealing forces are directed radially outward or radially inward around the axis X, depending on whether the outward or inward sealing surface is involved. In other words, the compressive force is still not axial (i.e., in the longitudinal direction along the axis X), but is generally radial. However, there are applications where in each of these non-circular structures, the sealing force is not directly aligned towards or away from the axis X.

[0141] More generally, a radial seal includes a sealing surface that surrounds (is oriented towards / away from) the central axis. In many cases, this central axis will include the central axis of the filter element, and the medium is also positioned around this axis. However, as can be understood from the alternative structures described below in this document, a radial seal can be a seal around an axis that is not the central axis of the filter element (in contrast, an axial seal is a seal that is generally aligned with the central axis around which the seal is provided, and this axis is usually but not necessarily in all cases the central filter element axis X).

[0142] In the general terms used herein, the various housing seal structures shown can also be characterized as generally including radially oriented sealing surfaces because the sealing directions of the various housing seals shown in the figures generally cause the sealing surfaces to engage a part of the housing (which can be a part of the outlet pipe or an external part of the housing, depending on which of the two housing seals is involved), which can generally be characterized as a "radially oriented surface". In each case, the surface that actually forms the seal is oriented around (and towards or away from) the central axis X (which is usually also the central axis of the filter element), rather than an axial seal, which typically has a sealing force oriented in the longitudinal direction along the central axis X. The example shown is an "outward radial sealing surface" or an "outwardly oriented radial seal" because the actual surface of the seal on the filter element that will form the seal with the housing is generally oriented away from the central axis of the filter element, rather than towards the axis. However, many of the principles described herein can be applied to alternative structures where the sealing surface on the filter element that engages the housing to form the seal is oriented radially towards the central axis.

[0143] The radial housing seals described herein can generally be characterized as "non-clamp", "non-clamping", or "clampless" structures or similar terms. This means that the seal structure generally does not involve the use of clamps such as hose clamps or other structures that need to be tightened in order to provide a reliable seal. Instead, the seal is established only by installation, where the sealing material is pressed against the surface of the housing and is guided by the filter element component.

[0144] The principles described herein can be applied to various filter components. Examples of applying the principles to (air) gas filter components are described. The examples described include air filters and crankcase ventilation filter components. The principles can be applied to various alternative gas filtration structures and, in some cases, even to liquid filter components.

[0145] The principles according to the present invention relate to the interaction between a filter element and an air filter system to achieve certain selected desired effects discussed below in an advantageous manner. The filter element generally includes a filter medium therein through which air and other gases pass during a filtering operation. The medium can have various types and configurations and can be made of various materials. For example, a pleated medium structure can be used in a filter element according to the principles of the present invention, as described below.

[0146] The principles are particularly applicable to cases where the medium extends deeply between the inlet and outlet ends of the filter element, but alternatives are possible. Additionally, the principles are generally used in filter elements with relatively large cross-sectional dimensions. With such a structure, a medium type other than a pleated medium is typically desired.

[0147] In this section, some examples of medium structures that can be used with the techniques described herein are provided. However, it should be understood that various alternative medium types can be used. The selection of the medium type is generally preferably one of the following: availability; functionality in a given application, ease of manufacturability, etc., and the selection is not particularly necessarily related to the overall functionality of the selected features among the various filter element / air filter interaction characteristics characterized herein.

Claims

1. An air filter element, comprising: a filter medium that extends between opposite first and second ends along a longitudinal axis, the filter medium defining an open inner space and an outer periphery; an open end cap disposed at the first end of the medium; a closed end cap disposed at the second end of the medium; a sealing structure disposed on the open end cap, the sealing structure having a profile that varies axially between a first radial plane and a second radial plane, wherein a first portion of the sealing structure is disposed at a first axial position and a second portion of the sealing structure is disposed at a second axial position, the first and second portions being highly separated and interconnected by an inclined intermediate portion, wherein the edge of the first portion furthest from the closed end cap extends along the first radial plane and the edge of the second portion closest to the closed end cap extends along the second radial plane, wherein the radial planes extend orthogonally with respect to the longitudinal axis and are highly separated, and wherein at least a portion of the sealing structure is disposed within the inner space of the filter medium opening or around the outer periphery of the filter medium; and a plurality of axially extending grooves disposed within the open end cap and extending through the first radial plane defined by the first portion of the sealing structure.

2. The air filter element according to claim 1, wherein the sealing structure and the plurality of axially extending grooves are disposed on the radially inner side of the open end cap.

3. The air filter element according to claim 1, wherein the sealing structure and the plurality of axially extending grooves are disposed on the radially outer side of the end cap.

4. The air filter element according to any one of claims 1-3, wherein the end cap is formed of polyurethane.

5. The air filter element according to claim 1, further comprising: a plurality of circumferentially spaced extensions that extend from the end face of the open end cap to a distal end, wherein the axially extending grooves extend into the extensions.

6. An air filter assembly, comprising: an openable filter housing that defines an interior having a radial cavity, the housing including a plurality of axially extending ribs at an outlet end of the housing; and the air filter element according to claim 1 removably disposed within the inner cavity of the housing, the grooves engaging the axially extending ribs.

7. An air filter assembly, comprising: an openable filter housing that defines an interior having a radial cavity, the housing including a first plurality of axially extending ribs disposed around a first side of an outlet structure of the housing and a second plurality of axially extending ribs disposed around a second side of the outlet structure; the first air filter element according to claim 1 removably disposed within the inner cavity of the housing; and a plurality of axially extending grooves disposed within the radially inner side of the open end cap, the grooves engaging the first plurality of axially extending ribs of the housing; and a second air filter element according to claim 1 removably disposed within the inner cavity of the housing, the plurality of axially extending grooves of the second air filter element being disposed within the radially outer side of the open end cap, the grooves engaging the second plurality of axially extending ribs of the housing.

8. An air filter element, comprising: A filter medium that extends between opposite first and second ends along a longitudinal axis; An open end cap disposed at the first end of the filter medium; A sealing structure disposed on the open end cap, the sealing structure having a profile that varies axially between a first radial plane and a second radial plane; and A plurality of axially extending grooves that are recessed within the open end cap and extend past the first radial plane defined by the sealing structure, at least some of the plurality of axially extending grooves having a radially facing open side, wherein the sealing structure and the plurality of axially extending grooves are located on a common radial side of the open end cap.

9. The air filter element according to claim 8, wherein the sealing structure and the plurality of axially extending grooves are disposed on the radially inner side of the open end cap.

10. The air filter element according to claim 8, wherein the filter medium defines an open interior space and the sealing structure is disposed within the open interior space.

11. The air filter element according to claim 8, wherein the sealing structure and the plurality of axially extending grooves are disposed on the radially outer side of the open end cap.

12. The air filter element according to claim 11, wherein at least a portion of the sealing structure is disposed around the outer periphery of the filter medium.

13. The air filter element according to claim 8, further comprising: a) A plurality of circumferentially spaced extensions that project from the end face of the open end cap.

14. The air filter element according to claim 13, wherein the plurality of axially extending grooves are disposed within the extensions.

15. An air filter element, comprising: A filter medium that extends between opposite first and second ends along a longitudinal axis, the filter medium defining an open interior space and an outer periphery; An open end cap disposed at the first end of the media pack; A sealing structure disposed on the open end cap, the sealing structure having a profile that varies axially between a first radial plane and a second radial plane, wherein at least a portion of the sealing structure is disposed within the open interior space of the filter medium or around the outer periphery of the filter medium; A plurality of axially extending grooves that are disposed within the open end cap and extend past the first radial plane defined by the first portion of the sealing structure.

16. The air filter element according to claim 15, wherein the sealing structure and the plurality of axially extending grooves are disposed on the radially inner side of the open end cap.

17. The air filter element according to claim 15, wherein the sealing structure and the plurality of axially extending grooves are disposed on the radially outer side of the closed end cap.

18. The air filter element according to any one of claims 15 - 17, wherein the end cap is formed of polyurethane.

19. The air filter element according to claim 15, further comprising: a) A plurality of circumferentially spaced extensions that extend from the end face of the open end cap to a distal end.

20. The air filter element according to claim 19, wherein the axially extending grooves extend into the extensions.

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