Patent Publication Number: US-2023149844-A1

Title: Filter elements, air cleaner assemblies, and methods of use and assembly

Description:
RELATED APPLICATIONS 
     This application is a Divisional of U.S. patent application Ser. No. 16/465,874, filed May 31, 2019, which is a National Stage application of PCT International application No. PCT/US2017/064260, filed Dec. 1, 2017, which claims the benefit of priority to U.S. Provisional Patent Application No. 62/428,913, filed Dec. 1, 2016, and U.S. Provisional Patent Application No. 62/463,263, filed Feb. 24, 2017, which applications are incorporated herein by reference. To the extent appropriate, a claim of priority is made to each of the above disclosed applications. 
    
    
     FIELD OF THE DISCLOSURE 
     The present disclosure relates to filter assemblies, for example air cleaner assemblies, and components and features thereof, and methods of assembly and use. The filter assemblies comprise a housing having a removable and replaceable filter cartridge therein. Various features of filter housings and/or the cartridges are described, which can provide for advantage. Methods of assembly and use are described. 
     BACKGROUND 
     Air or other gas filtering is desirable in a number of systems. A typical application is in the filtration of intake air to internal combustion engines. Another is in the filtration of crankcase ventilation filter assemblies. Typically, such systems comprise filter assemblies having a serviceable filter cartridge therein. After a period of use, filter media within a filter housing requires servicing, either through cleaning or complete replacement. Typically, for an air cleaner or crankcase ventilation filter assembly used with an internal combustion engine, for example on a vehicle, the filter media is contained in a removable and replaceable, i.e. serviceable, component, typically referred as a filter element or cartridge. The filter cartridge is configured to be removably sealed within the air cleaner, in use. Improvements in filter arrangements relating to assembly, serviceability, use are desirable. The filter cartridge can be provided as a primary filter cartridge or a secondary filter cartridge. The air cleaner assembly can contain only a primary filter cartridge or both a primary filter cartridge and a secondary filter cartridge. 
     SUMMARY 
     Filter assemblies (such as air cleaner assemblies or crankcase ventilation filter assemblies) components therefor; and, features thereof are described. Also described are methods of assembly and use. The filter assemblies generally comprise a housing having a filter cartridge removably positioned therein. 
     An example assembly includes a first filter cartridge and a second filter cartridge, wherein the first filter cartridge has a first sealing structure configured for sealing against a portion of a housing and having a sealing surface, and wherein the second filter cartridge has a second sealing structure configured for sealing against the first filter cartridge sealing surface. In one embodiment, the first sealing structure is an outwardly directed radial seal while the second sealing structure is an inwardly directed radial seal. Another example assembly includes a first filter cartridge having filtration media defining an interior space with an open end cap at one end and having a sealing structure that is located entirely within the interior space and spaced from the open end cap. In one embodiment, the sealing structure is an outwardly directed radial seal. Another example assembly includes a removable seal surface component installed onto a portion of the housing, wherein a first filter cartridge has a first sealing structure that seals against an interior portion of the removable seal surface component, and wherein a second filter cartridge has a second sealing structure that seals against an outward portion of the removable seal surface component. 
     There is no specific requirement that an air cleaner assembly, component therefor, or feature thereof include all of the detail characterized herein, to obtain some advantage according to the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of an air cleaner assembly including a housing assembly with at least one filter cartridge installed therein according to the present disclosure. 
         FIG.  2    is a top view of the air cleaner assembly shown in  FIG.  1   . 
         FIG.  3    is an exploded view of the air cleaner assembly shown in  FIG.  1   , wherein a first filter cartridge, a second filter cartridge, and a serviceable seal surface component are shown as being utilized in conjunction with the housing assembly. 
         FIG.  4    is a cross-sectional view of the air cleaner assembly of  FIG.  1   , taken along the line  4 - 4  in  FIG.  2   , with the components shown in  FIG.  3    installed within the housing assembly. 
         FIG.  4 A  is an enlarged cross-sectional view of a portion of the air cleaner assembly shown in  FIG.  4   , as indicated at  FIG.  4   . 
         FIG.  5    is a cross-sectional view similar to  FIG.  4   , but with the housing assembly not being shown. 
         FIG.  6    is a perspective view of the serviceable seal surface component shown in  FIG.  3   . 
         FIG.  7    is a cross-sectional view of the serviceable seal surface component shown in  FIG.  7   . 
         FIG.  8    is a cross-sectional view of the second filter cartridge shown in  FIG.  3   . 
         FIG.  9    is a cross-sectional view of the first filter cartridge shown in  FIG.  3   . 
         FIG.  10    is an exploded view of the air cleaner assembly shown in  FIG.  1   , wherein a second example of a first filter cartridge is shown as being utilized in conjunction with the housing assembly. 
         FIG.  11    is a cross-sectional view of the air cleaner assembly of  FIG.  1   , taken along the line  4 - 4  in  FIG.  2   , with the components shown in  FIG.  10    installed within the housing assembly. 
         FIG.  11 A  is an enlarged cross-sectional view of a portion of the air cleaner assembly shown in  FIG.  11   , as indicated at  FIG.  11   . 
         FIG.  12    is a cross-sectional view similar to  FIG.  11   , but with the housing assembly not being shown. 
         FIG.  13    is a cross-sectional view of the first filter cartridge shown in  FIG.  10   . 
         FIG.  14    is an exploded view of the air cleaner assembly shown in  FIG.  1   , wherein a third example of a first filter cartridge and a second example of a second filter cartridge are shown as being utilized in conjunction with the housing assembly. 
         FIG.  15    is a cross-sectional view of the air cleaner assembly of  FIG.  1   , taken along the line  4 - 4  in  FIG.  2   , with the components shown in  FIG.  14    installed within the housing assembly. 
         FIG.  15 A  is an enlarged cross-sectional view of a portion of the air cleaner assembly shown in  FIG.  15   , as indicated at  FIG.  15   . 
         FIG.  16    is a cross-sectional view similar to  FIG.  15   , but with the housing assembly not being shown. 
         FIG.  17    is a cross-sectional view of the second filter cartridge shown in  FIG.  14   . 
         FIG.  18    is a cross-sectional view of the first filter cartridge shown in  FIG.  14   . 
         FIG.  19    is a cross-sectional view of the air cleaner assembly shown in  FIG.  1   , wherein the second example of a first filter cartridge and a third example of a second filter cartridge are shown. 
         FIG.  20    is an enlarged cross-sectional view of a portion of the air cleaner assembly shown in  FIG.  19   . 
         FIG.  21    is a cross-sectional view of the air cleaner assembly shown in  FIG.  1   , wherein the first example of a first filter cartridge and a fourth example of a second filter cartridge are shown. 
         FIG.  22    is an enlarged cross-sectional view of a portion of the air cleaner assembly shown in  FIG.  21   . 
     
    
    
     DETAILED DESCRIPTION 
     Herein, example filter assemblies, filter cartridges, features and components therefor are described and depicted. A variety of specific features and components are characterized in detail. Many can be applied to provide advantage. There is no specific requirement that the various individual features and components be applied in an overall assembly with all of the features and characteristics described, however, in order to provide for some benefit in accord with the present disclosure. 
     It is noted that a plurality of embodiments are depicted and described. The embodiments are not meant to be exclusive with respect to features depicted. That is, selected features of one embodiment can be applied in one or more of the other embodiments if desired, to advantage. In many examples, the filter assembly depicted is an air cleaner assembly, for example, used to filter intake air for an internal combustion engine. However, the concepts disclosed are not in any way limited to such an application and may be applied across a variety of different applications, such as crankcase ventilation. The disclosed filter assemblies are generally “gas filter assemblies,” since the carrier stage being filtered is gas (air or crankcase ventilation gases). While the techniques described herein will typically be used in application for gas filtration, they can be used in the filtration of other materials, for example, liquids, if desired. 
     I. Filter Assembly—General Description 
     The reference numeral  1 ,  FIG.  1   , generally indicates a filter assembly, for example an air cleaner or air cleaner assembly or arrangement in accord with the present disclosure. The filter assembly (in the example an air cleaner assembly)  1  comprises a housing  2 . The housing  2  defines a sidewall  2   s  and includes: a first body or housing section  3 ; and a second body section or access cover  4 . In the example depicted, the access cover  4  is removably secured to the first body section  3 , but alternatives are possible. Also although alternatives are possible, for the example depicted, attachment of the cover section  4  to the body section  3  is by a latch arrangement  5  including over center latches. The cover section  4  can alternatively be held to the body section  3  by a twist lock arrangement. An exemplary twist lock arrangement is depicted in U.S. application Ser. No. 15/192,272, filed on Jun. 24, 2016, the disclosure of which is incorporated herein by reference. 
     In general, the air (gas) cleaner  1  includes an air (gas) flow inlet arrangement  7 . In the example depicted, the air flow inlet arrangement  7  is an inlet tube indicated at  7   t , on the body section  3 . The particular inlet tube  7   t  depicted, is configured as a side, tangential, inlet, i.e. gas flow is directed tangentially against an inner wall of housing  2 , as opposed to being directed directly toward a housing central axis X. Alternate inlet arrangements, locations and direction are possible. However, the tangential inlet arrangement depicted is convenient and advantageous for reasons discussed below. 
     At  8 , a dust/water ejector arrangement is depicted on the housing  2 , comprising tube  9 . In the example depicted, the tube  9  comprises a portion of access cover  4 , although alternatives are possible. The tube  9  is covered by an evacuator valve arrangement  10 , in the example depicted comprising a duck-billed valve of a type widely used with air cleaners, see for example WO 2006/06241 A1; U.S. Pat. Nos. 6,419,718 B1; and 8,864,866, incorporated herein by reference. Alternate evacuator valve arrangements can be used. 
     At  15 , an outlet tube or flow tube is depicted, as a portion of housing  2  positioned on a remainder of the housing body section  3 . The tube  15  can be formed integral with the housing body  3 , but the outlet tube  15  can be a separate piece snap-fit or otherwise attached to the housing body  3 . 
     In operation, air (gas) to be filtered enters the air cleaner assembly through inlet tube  7   t . Eventually the air/gas passes through filter media of a filter cartridge arrangement positioned within interior  2   i  of the housing  2 . After passage through media of the filter cartridge, the filtered air is directed to exit the housing through outlet tube  15 . From outlet tube  15 , the filtered air is directed to downstream equipment such as to a turbo system or to the air intake of an engine system. 
     The particular air cleaner (filter) assembly  1  depicted includes an optional precleaner stage. The precleaner stage is provided in part by directing air from inlet tube  7   t  tangentially into interior  2   i  of the housing  2 . The air will then be directed into a cyclonic pattern around an interior of the assembly  1 . This will tend to drive a portion of any water or dust particles contained within the air stream, against an interior surface of sidewall  2   s . This material, separated from the air stream, will eventually migrate to, and enter, the tube  9 , from which ejection occurs through valve  10 . 
     The particular air cleaner assembly  1  depicted is configured so that it can be mounted in a variety of orientations, for example with the central axis X directed vertically, or alternatively with the central axis X directed horizontally. 
     The housing body section  3  can include a mounting pad arrangement thereon. The mounting pad arrangement can be formed integral with a remainder of the housing  2  or it can be a separate piece. The mounting pad arrangement is used to help secure the housing  2  in place, on equipment with which air cleaner  1  would be used. By having the mounting pad arrangement on the housing section  3 , the housing section  3  can be retained in place on the equipment by bolts, or other systems during servicing, with access cover  4  being removably secured to body section  3 , for convenient servicing. An exemplary mounting pad arrangement that can be used as part of the housing section  3  is disclosed in U.S. Pat. No. 8,864,866, the disclosure of which is incorporated herein by reference. 
     As thus far described the air cleaner assembly is similar to many prior air cleaner assemblies, including those depicted and described in WO 2006/06241 A1; WO 2009014988; U.S. Pat. Nos. 6,419,718 B1; and, 8,864,866, the disclosures of which are incorporated herein by reference. 
     Reference is now made to  FIGS.  3  and  4   , which show the housing assembly of  FIGS.  1  and  2    used in conjunction with a first example of serviceable internal filtration components that can be provided within the housing  2 . In the exploded view of  FIG.  3   , filter cartridge  25 , filter cartridge  27 , and serviceable seal surface component  17  are viewable and shown as being positionable within housing interior  2   i . Alternative serviceable component arrangements which utilize the same housing  2  are shown at  FIGS.  10  to  13    and at  FIGS.  14  to  18   . The variations of filter cartridge  25  will be described in greater detail below. In general, the cartridge  25  is a serviceable component that includes an extension of filter media  26  through which air to be filtered passes, before it can exit assembly  1 . In addition, the variations of filter cartridge  27  will be described in greater detail below. In general, the cartridge  27  is a serviceable component that includes an extension of filter media  28  through which air to be filtered passes before it exits assembly  1 . The filter cartridge  25  can be referred to as a primary filter cartridge or primary filter element, and the filter cartridge  27  can be referred to as a secondary or safety filter cartridge or secondary or safety filter element. The serviceable seal surface component  17 , which is present in only the first embodiment at  FIGS.  3  to  9   , will also be described in greater detail below. 
     By the term “serviceable component” as used herein, and in reference to the cartridges  25  and  27  and seal surface component  17 , it is meant that the seal surface component  17  and cartridges  25 ,  27  are removable and replaceable in the air cleaner assembly  1 . Thus, as the media  26  and/or  28  occludes during use, the cartridge  25  and/or the cartridge  27  can be removed, and can be refurbished or replaced. Similarly, as the seal surface component  17  becomes worn, damaged, or otherwise unsuitable for use, the seal surface component  17  can be removed, and can be refurbished or replaced. 
     Referring to  FIG.  2   , it can be seen that housing  2  includes an optional, but advantageous, shield arrangement  29  surrounding a selected portion of the filter cartridge  25 . The shield arrangement  29  includes first shield section  30  in housing body section  3 , oriented to surround a portion of the cartridge  25  at that location, creating an annulus  31  between the shield  30  and outer sidewall  32 . Air from inlet  7  is directed into inlet aperture  7   a  and into annulus  31 , and in a cyclonic pattern. Shield  30  inhibits direct impingement, of the dust and other material carried by the inlet air in annulus  31 , and onto the media  26  until after the air has moved at least partially through the cyclonic pattern and past shield  30  in a direction toward access cover  4 . 
     In  FIG.  4   , at  33  a second shield section of shield arrangement  29  is depicted in access cover  4 . The second shield section  33  defines an annulus  34  between the shield  33  and sidewall  35  of section  4 . As shown at  FIG.  1   , an egress or outlet aperture is located in the sidewall  2  from housing interior  2   i  to interior  9   i  of tube  9 . The egress or outlet aperture  37  is in communication with the annulus  34 . The shield  33  helps facilitate removal of dust and other materials through aperture  37  into dust ejector arrangement  8 . 
     Use of shield arrangements analogous to shield arrangement  29 , with one or more shields analogous to sections  30  and  33 , is common in many air cleaner arrangements, see for example WO 2006/06241 A1; WO 2009/014988; U.S. Ser. Nos. 61/446,653; 61/473,296; U.S. Pat. Nos. 6,419,718 B1; and 8,864,866, the disclosures of which are incorporated herein by reference. Analogous features and principles can be used here. 
     It is noted that the use of the shield arrangement  29  and dust ejector arrangement  8  is consistent with many applications in which a “dual stage” or “two stage” air (gas) cleaner is desired, having a first precleaner stage to separate water and larger particles from the air before it passes into the filter cartridge  25  (the second stage). However, such features are generally optional, and many of the principles of the present disclosure can be applied in air cleaners that do not have such a two stage configuration or precleaner stage. Downstream of the filter cartridge  25  is the secondary filter cartridge  27  so that air passes through both of the filter cartridge  25  and the filter cartridge  27  prior to exiting via the air outlet  15 . It should be understood that the air cleaner assembly  1  can be operated with the filter cartridge  25  alone, with the filter cartridge  27  alone, or with both the filter cartridge  25  and the filter cartridge  27  provided together and as shown in  FIG.  2   . 
     II. Filter Assembly—First Filter Arrangement Embodiment 
     As indicated above, many of the features previously identified and discussed with respect to  FIGS.  1 - 2    relating to general air cleaner configuration (filter assembly) and operation are well known features, forms of which have been used in a variety of systems. Certain unique characteristics of the present air cleaner, of  FIGS.  1 - 2  and  3 - 9   , relate to the inclusion of the serviceable seal surface component  17 . The serviceable seal surface component  17  provides seal surfaces against which the filter cartridges  25 ,  27  can be sealed. As the component  17  is serviceable, a new sealing surface can be provided in the assembly at any point in time, for example, when wear or damage to the component  17  occurs or when damage to an originally provided permanent seal surface (e.g. filter cartridge baffle  114 ) on the housing  2  becomes worn or damaged. In this section, selected features relating to the serviceable seal surface component  17  are discussed. 
     As most easily seen at  FIGS.  6  and  7   , the serviceable seal surface component  17  includes a main body  17   a  (e.g., ring or annular-shaped) extending from a first end  17   b  to a second end  17   c . Between the first end  17   b  and the second end  17   c , the main body  17   a  includes a first extension segment  17   d  and a generally parallel second extension segment  17   e  joined by a connecting portion  17   f  . The first and second extension segments  17   d ,  17   e  are spaced apart such that an annulus  17   g  is formed therebetween. The second extension part  17   e  is further joined to a seal structure  17   h  which defines a channel  17   i  into which a seal member  17   j  is received. In one aspect, the main body  17   a  of the component  17  includes an inwardly stepped portion  17   p . The inwardly stepped portion  17   p  can act as a stop against which the end of the filter cartridge  27  can rest. 
     As presented, the main body  17   a  is an integrally formed unit having all of the aforementioned components  17   b - 17   i  with the exception of the seal member  17   j . In the example shown, the seal member  17   j  is a separate O-ring. However, in an alternative arrangement, the seal member  17   j  can also be integrally formed as a portion of the main body  17   a . Additionally, the first and second extensions  17   d ,  17   e  themselves may provide the sealing surfaces. The main body  17   a  may be formed from a variety of materials, such as an injection molded polymeric material. 
     In one aspect, the first extension part  17   d  defines an outer sealing surface  17   k  and an inner sealing surface  17   m  while the second extension part  17   e  defines an inner sealing surface  17   n  and an outer sealing surface  17   o . When the serviceable seal surface component  17  is installed into the housing  2 , a filter cartridge baffle  114  of the housing  2  is received into the annulus  17   g  formed between the first and second extension parts  17   d ,  17   e  until, for example, contact is made between an end  114   a  of the filter cartridge baffle  114  or between the second end  17   c  of the main body  17   a  and a surface of the housing  2 . As configured, the filter cartridge baffle  114  is a portion of the outlet tube  15  that extends into the interior volume  2   i  of the housing  2 . Once the component  17  is fully inserted, the component surface  17   m  faces an outer surface  114   c  of the baffle  114  while the component surface  17   o  faces an inner surface  114   b  of the baffle  114 . In this position, and as most easily seen at  FIG.  4 A , the seal member  17   j  forms a seal against the inner surface  114   b  of the filter cartridge baffle  114 . This seal formed between the seal member  17   j  and the filter cartridge baffle  114  ensures that a continuous seal will exist between the filter cartridge baffle  114  and any component sealed to the serviceable seal surface component  17 . 
     In some applications, the surfaces  114   b  and  114   c  of the filter cartridge baffle  114  initially serve as the sealing surfaces against which the filter cartridges  25 ,  27  form a seal. Over time, one or both of these surfaces may become worn or damaged. In such cases, the serviceable seal surface component  17  can be mounted onto the filter cartridge baffle  114  to provide new seal surfaces  17   n ,  17   k . As the seal member  17   j  is located proximate the second end  17   c  of the main body  17   a  and adjacent to the seal surface  17   n , the seal member  17   j  does not interfere with a seal between the component  17  and a filter cartridge  27 . It may also be useful to install the serviceable seal surface component  17  in instances where it is desired to provide a filter cartridge  25  or  27  having seals that are sized or shaped incompatibly with the filter cartridge baffle  114 . 
     The filter cartridge  25  can be referred to as a primary filter cartridge or as a primary filter element, and the filter cartridge  27  can be referred to as a secondary or safety filter cartridge or as a secondary or safety element. In general, the primary filter cartridge or primary filter element and the secondary or safety filter cartridge or the secondary or safety filter element can be referred to as the filter cartridge or the filter element for convenience. Based on context, it should be apparent that references being made to the primary filter cartridge or the secondary filter cartridge. 
     In general terms, again, the cartridges  25  and  27  are serviceable components. That is, they can be removed and replaced through the lifetime of the air cleaner  1 , just as described for the serviceable seal surface component  17 . A releasable seal is needed between the cartridge  25  and the serviceable seal surface component  17 , and between the cartridge  27  and the component  17 , to allow the cartridges to be serviceable components and to ensure that unfiltered air does not bypass the cartridge  25  and/or the cartridge  27  and enter the outlet tube  15 , as this can cause damage to the engine. 
     The filter cartridge  25  generally includes filtration media  26  extending between first and second opposite media ends  41  and  42 . First media end  41  is engaged by a first end cap or piece  45 . The second media end  42  is engaged by a second end cap or piece  46 . Thus, the media  26  extends between opposite end caps (or end pieces)  45 ,  46 . 
     Although alternatives are possible with selected techniques described herein, for the example depicted, the filter media  26  is configured surrounding an open filter interior  26   i , generally around a central axis X of the air cleaner  1  and cartridge  25 . The media  26  can be pleated media, although alternatives are possible. The media  26  can be configured in a cylindrical pattern as shown, if desired, although alternatives are possible. For example, the media  26  can be somewhat conical in extension between the opposite ends  41 ,  42 . Also, the media can be configured with non-circular inner and/or outer perimeters; for example oval or other cross-sectional configurations are possible. In addition, the primary filter cartridge  25  can be provided with a screen or support structure  26 s extending from the first end  41  to the second  42  to help support the filtration media  26  while allowing gas (air) to pass therethrough. The filtration media  26  can be embedded in the first and second end caps  45  and  66 . In addition, the screen or support structure  26 s for the filtration media  26  can be embedded in the first and second end caps  45  and  46 . 
     Although alternatives are possible with selected techniques described herein, the second end piece or cap  46  is typically a closed end piece or cap, extending completely across the media  26  at the second end  42 , closing that end  42  of the media  26  and the filter interior  26   i . That is, end piece or cap  46 , for the example depicted, is a closed end piece or cap, i.e. an end cap having no aperture therethrough in communication with the open filter interior  26   i.    
     First end piece or cap  45  on the other hand, is an open end piece or cap. That is, it surrounds and defines a central aperture  50  in communication with the media, in the example via open filter interior  26   i . In typical use, aperture  50  is an air flow exit aperture from the media, for example open filter interior  26   i , for filtered air. In alternate applications with a reverse direction of gas flow during filtering, aperture  50  can be an inlet aperture. In general, it is a gas flow aperture. 
     For the example depicted, first end piece  45  extends completely across all media  26  of the cartridge  25 , from an outer perimeter  26   x  to an inner perimeter  26   o . The first end piece  45  typically has only one, central, aperture  50  therethrough. 
     Again, when the access cover  4  is removed from the housing body section  3 , access to interior  2   i  is provided for either installation or removal of the cartridge  25 . The filter cartridge  25 , then, needs to be adequately removably sealed to the serviceable seal surface component  17  to protect against flow of unfiltered air into the exit tube  15 . To provide for this, the cartridge  25  is provided with a primary (or housing) seal arrangement  55 . 
     With respect to the first housing seal or primary seal arrangement  55 , and other features of first end cap  45 , attention is directed to  FIGS.  4 ,  4 A, and  9   . The primary seal arrangement  55  can be seen as defining a radially directed seal or seal surface  55   s  directed to engage the surface  17   k  of the serviceable seal surface component  17 , for releasable sealing. Accordingly, the primary seal arrangement  55  forms an inwardly directed radial seal with the serviceable seal surface component  17  when the primary filter cartridge  25  is installed in the filter assembly  1 . 
     Still referring to  FIGS.  4 ,  4 A, and  9   , it will be understood that the surface  55   s , of primary seal arrangement  55 , that forms a seal with component  17  is generally a radially directed surface. Hence, the primary seal arrangement  55  can be referred to as a radially directed seal. By “radially” in this context, it is meant that the seal or seal surface (and the compression of the seal surface during sealing) is directed generally toward or away from (i.e. around) central axis X. The particular surface  55   s  in the example depicted, is radially inwardly directed relative to the central axis X, so the seal arrangement  55  can be characterized as “radially inwardly directed.” It is noted however, that a radially outwardly directed seal can be used with some principles in accord with the present disclosure. 
     It is noted that in the example depicted, the housing seal arrangement  55  comprises a portion of end cap  45 . In more general terms, the housing seal arrangement is mounted on a filter cartridge and is configured to releaseably seal to a housing or component  17 , whether that particular housing seal arrangement comprises a portion of an end piece or not. 
     The preferred and advantageous housing seal arrangements described herein are generally “non-clamp” or “clampless” housing seal arrangements. By this it is meant that they are established as the cartridge is inserted into the housing, without the need for tightening the clamp or connector of some type. 
     In one aspect, the end cap  45  and seal arrangement  55  can be constructed in a manner so that the amount of radial compression of end piece (cap) material in a region between surface  55   s  and the support  62  will have a maximum compression of at least 10%, typically at least 15%, preferably no more than about 40% and will typically be with a maximum compression within the range of about 20-40%, inclusive. In some implementations, a compression between 30-40% is useful. To accomplish this, a seal support can be provided within the end cap  45 . 
     Now referring to the filter cartridge  27  depicted in  FIGS.  4 ,  4 A, and  8   . The filter cartridge  27  can be referred to a secondary filter element or as a safety filter element. During the servicing of the filter assembly  1 , wherein the primary filter cartridge  25  is removed and replaced with a new or refurbished filter cartridge, the secondary filter element  27  prevents dust or debris from entering into the outlet tube  15 . Furthermore, in the event of a malfunction in the primary filter cartridge  25 , the secondary filter cartridge  27  is available to prevent dust or debris from entering the outlet tube  15 . 
     The secondary filter cartridge  27  includes a first end  80 , and second end  82 , and filtration media  28  extending between the first end  80  and the second end  82 . In the exemplary secondary filter cartridge  27  depicted, the first end  80  includes a first endcap  84  and the second end  82  includes a second end cap  86 . The secondary filter cartridge  27  can be provided, if desired, without a second end cap  86 . That is, the secondary filter cartridge  27  can be provided so that the media extends over the second end  82 . In addition, the secondary filter cartridge  27  can be provided with a screen or support structure  90  extending from the first end  80  to the second  82  to help support the filtration media  28  while allowing gas (air) to pass therethrough. The filtration media  28  can be embedded in the first and second end caps  84  and  86 . In addition, the screen or support structure  90  for the filtration media  28  can be embedded in the first and second end caps  84  and  86 . 
     The secondary filter cartridge  27  can be constructed so that the filtration media  28  is configured surrounding an open filter interior  28   i . The media  28  can be provided as depth media, although alternatives are possible. For example, the media  28  can be provided as pleated media or as multilayer laminate media such as the media disclosed in PCT Publication No. WO 2015/010085, the entire disclosure of which is incorporated herein by reference. In addition, the media  28  can be provided as the filtration media layer arranged in a wave configuration disclosed in PCT Publication No. WO 2015/010085. The media  28  can be configured in a cylindrical pattern as shown, if desired, although alternatives are possible. For example, the media  28  can be somewhat conical in extension between the opposite ends  80 ,  82 . In addition, the media can be configured with non-circular inner and/or outer perimeters. For example, the media can be configured having an oval, circular, or other cross-sectional configuration. 
     The second end cap  86  can be provided as a closed end piece or cap, extending completely across the media  28  at the second end  82 , closing the second end  82  of the filtration media  28  of the filter interior  28   i . An exemplary top view of the second end cap  86  is shown, for example, in  FIG.  8   . The second end cap  86  can include projections  86 p that help provide separation and cushioning between the secondary filter cartridge  27  and the primary filter cartridge  25 . Furthermore, the second end cap  86  can include a plurality of radially extending ridges. 
     The second end piece or cap  86  can be characterized as a closed end piece or cap, i.e. an end cap having no aperture therethrough in communication with the open filter interior  28   i . In various alternative configurations, the second end  82  can be provided without an end cap. In one variation of the secondary filter element  27  without a second end cap  86 , the filtration media  28  extends over and encloses the second end  82 . That is, the filtration media  28  can form the closure at the second end  82  thereby preventing unfiltered air from entering into the open filter interior  28   i . In an alternative, the second end  82  can be provided with a seal arrangement that mounts onto a secondary filter element support structure wherein the support structure includes a closed end corresponding to the second end  82  of the secondary filter cartridge  27 . A remaining portion of the support structure would be open to flow of gas (air) therethrough. However, the closed end of the support structure would, in combination with the seal at the second end of the secondary filter cartridge  27  prevent unfiltered air from entering into the open filter  28   i.    
     The first end cap  84  includes a support  92  and a secondary seal member  94 . The support  92  can be provided as part of the screen or support structure  90  or the support  92  can be provided as a separate component such as a plastic preform. As shown in  FIG.  8   , the support  92  is part of the screen  90 . That is, the screen  90  extends into the secondary seal member  94  a sufficient amount to help support the secondary seal member  94  when provided in a sealing relationship with the housing  2 . The combination of the screen  90  (or support  92 ) and the secondary seal member  94  forms the first end cap  84 . The support  92  helps support the secondary seal member  94  when it engages the serviceable seal support structure  17 . The secondary seal member  94  can be referred to as a housing seal structure or arrangement for the secondary filter cartridge  27 . In general, the secondary seal member  94  can be molded onto the support  92  and provides an outwardly directed sealing surface  96 , directed to engage the surface  17   n  of the separate seal surface component  17 , for releasable sealing. When molded, the secondary seal member  94  can be provided having an outer section  94   o  on the outside of the support  92  and having an inner section  94   i  on the inside of the support  92 . In addition, the secondary seal member  94  can include a portion  94   t  extending over a tip of the preform  92 . The secondary seal member  94  extends in a perimeter around a central open volume  15   i . The central open volume  94   i  can be in communication with the open filter interior  28   i . During operation of the filter assembly  1  when the secondary filter cartridge  27  is installed, air passes through the filtration media  28  into the open filter interior  28   i , and then passes through the central open volume  94   i  and into the outlet tube  15 . 
     The secondary seal member  94  can be characterized as having an axial distance or height  94   h  from the bottom  94   b  to the top  94   a  that is sufficient to provide a seal with the serviceable sealing surface component  17 . As most easily seen at  FIGS.  4 ,  4 A, and  5   , the secondary seal member sealing surface  96  of the end cap  94  forms a seal with the inner sealing surface  17   n  of the second extension part  17   e  of the serviceable seal surface component  17 . 
     III. Filter Assembly—Second Filter Arrangement Embodiment 
     Referring to  FIGS.  10  to  13   , a second filter arrangement  101  is shown that can be utilized with the housing  2  depicted in  FIGS.  1  to  4   . As many of the features for this embodiment are similar to the those previously discussed for the first embodiment, the description for the first embodiment is incorporated into this description for the second embodiment. Where similar features do exist, similar reference numbers will be used, although in some instances a “100” series number will be used for the components of the second filter arrangement  101  (e.g. 125 for filter cartridge instead of 25). The following description will be limited to the differences of the second embodiment over the first embodiment. The primary difference is that that the second embodiment is not shown as including a safety filter cartridge  27  or a serviceable sealing surface component  17  and the main filter cartridge  125  of the second embodiment is configured with a remote sealing structure  155  that enables the main filter cartridge to seal to the inside surface  114   b  of the filter cartridge baffle  114 , even though, as shown, the cartridge is positioned primarily to the outside of baffle  114 . 
     Similar to the filter cartridge  25 , the filter cartridge  125  is shown with pleated media  126  forming an interior area  126   i  and extending between a first end  141  and a second end  142 , wherein an open end cap  145  is provided at the first end  141  and a closed end cap  146  is provided at the second end  142 . However, in this embodiment, the open end cap  145  is not provided with a seal structure or arrangement. Instead, a remote seal structure  155  is provided that is spaced inwardly from the open end cap  145  and that is disposed entirely within the interior area  126   i . As shown, the seal structure  155  defines a radially outward directed sealing surface  155   s  at a diameter D 155  which is less than an internal diameter D 145  of an interior surface  145   a  of the open end cap  145 . Accordingly, an annulus  157  is formed between the open end cap  145  and the seal structure  155 . Taken together, the end cap  145 , the seal structure  155 , and the interconnecting extension member  152 , discussed in detail below, can be collectively referred to as a seal arrangement  150 . 
     The seal structure  155  is supported by an extension member  152 . The extension member  152  extends between a first end  152   a  and a second end  152   b , wherein the first end  152   a  can be embedded within the open end cap  145  and the second end can be embedded in the seal structure  155 . The seal structure may be alternatively constructed to utilize an O-ring or an overmolded construction. As shown, the extension member  152  includes a first segment  152   c  extending from the first end  152   a  towards the closed end cap  146  and a second segment  152   d  extending from the second end  152   b  toward the closed end cap  146  in a spaced apart, parallel relationship with the first segment  152   c . The first and second segments  152 ,  152   d  are joined by a segment  152   e , the length of which determines the dimension of the resulting annulus  152   f  between the first and second segments  152   c ,  152   d . In one aspect, the length H 152   c  of the first segment  152   c  is less than the length H 152   d  of the second segment such that the end face  155   a  seal structure  155  is axially spaced or recessed from the end face  145   c  of the open end cap  145  by a distance D 1 . In such a configuration, the seal structure  155  can be characterized as being fully within the interior area  126   i  defined by the media  126 . 
     The seal structure  155  can be made from a similar material as the end cap  145 , such as a polyurethane material or an injection molded polymeric material. The extension member  152  can be formed from a variety of materials, for example polymeric and metal materials. In one example, the end cap  145 , the extension member  152 , and the seal structure  155  are integrally formed as a single component. 
     Referring to  FIGS.  11  to  12   , the installation of the filter cartridge  125  is shown as being installed within the housing  2 . As shown, the filter cartridge baffle  114  associated with the outlet tube  15  is received within the annulus  152   e  between the first and second segments  152   c ,  152   d  of the extension member  152 . The end cap  145  can be provided with a dimension and configuration such that the inner and outer radial surfaces  145   a ,  145   b  of the end cap seal against the filter cartridge baffle  114  and housing  2 , respectively. The end cap  145  can also be provided with a dimension and configuration such that no radial seal is formed with the filter cartridge baffle  114  and/or the housing  2 . As the filter cartridge  125  is received into the housing  2 , the seal structure  155  is received into the filter cartridge baffle  114  and the filter cartridge  125  will eventually reach its installed position in which the end face  145   c  of the end cap  145  is brought into contact with the housing  2 . In this position, the seal surface  155   s  compresses against the interior surface  114   b  of the filter cartridge baffle  114  to form a seal. As such, a sealed airflow path between the inlet  7  and outlet tube  15  is achieved such that all air flowing out of the outlet tube  15  must first pass through the filter cartridge  125 . This configuration is advantageous in instances where the housing may have been originally designed for use with a safety filter element and a main filter element that initially sealed directly against the filter cartridge baffle  114 , but where the outer surface  114   c  of the filter cartridge baffle  114  is no longer suitable for providing a sealing surface in cases of excessive damage or wear. Accordingly, the filter cartridge  125  can be utilized to extend the useful life of a filter assembly. 
     IV. Filter Assembly—Third Filter Arrangement Embodiment 
     Referring to  FIGS.  14  to  18   , a third filter arrangement is shown that can be utilized with the housing  2  depicted in  FIGS.  1  to  4   . As many of the features for this embodiment are similar to the those previously discussed for the first and second embodiments, the description for those embodiments is incorporated into this description for the second embodiment. Where similar features do exist, similar reference numbers will be used, although in some instances a “200” series number will be used for the components of the third filter arrangement  201  (e.g. 225 for filter cartridge instead of 25 or 125). The following description will be limited to the differences of the second embodiment over the first embodiment. The third embodiment is similar to the second embodiment in that the main filter element is provided with a seal structure that is remote from the end cap and within the interior space of the media. However, the third embodiment is different from the previous embodiments in that the secondary or safety filter cartridge is provided with a sealing surface against which the sealing structure of the main filter cartridge can be sealed. With such an arrangement, the outer surface  114   c  of the filter cartridge baffle  114  or another part of the housing  2  is not relied upon for forming a seal with the main filter cartridge. Thus, the third embodiment is advantageous in circumstances where the outer surface  114   c  may be worn or damaged or where the sealing interface with the housing  2  is work, damaged, or not compatible with the main filter element end cap and seal structure. In an alternative construction, the filter cartridge  225  is provided with a shorter length such that the seal structure extends axially away from the open end cap and is not disposed within the interior space of the media. 
     With reference to  FIGS.  14 - 18   , it can be seen that filter cartridge  225  is similar in construction to the filter cartridge  125  in that a seal structure  255  is provided that is remote from the end cap  245  and that is within the interior area  226   i  of the media  226 . The filter cartridge  225  is shown with pleated media  226  forming an interior area  226   i  and extending between a first end  241  and a second end  242 , wherein an open end cap  245  is provided at the first end  241  and a closed end cap  246  is provided at the second end  242 . 
     In contrast to the filter cartridge  125 , filter cartridge  225  has a seal structure  255  having an inwardly directed radial sealing surface  255   s . As mentioned previously, the remote seal structure  255  is provided such that it is spaced inwardly from the open end cap  245  and such that is disposed entirely within the interior area  126   i . As shown, the seal structure  155  defines a radially inward directed sealing surface  255   s  at a diameter D 255  that is less than an internal diameter of the end cap  245 . 
     The seal structure  255  is supported by an extension member  252 . Taken together, the end cap  245 , the seal structure  255 , and the interconnecting extension member  252  can be collectively referred to as a seal arrangement  250 . As shown, the extension member  252  extends between a first end  252   a  and a second end  252   b , wherein the first end  252   a  is embedded within or a part of the open end cap  245  and the second end is embedded in or attached to the seal structure  255 . As shown, the extension member  252  includes a first segment  252   c  extending from the first end  152   a  towards the closed end cap  246  and a second segment  252   d  extending from the second end  252   b  toward the closed end cap  246  in a spaced apart, parallel relationship with the first segment  252   c . The first and second segments  152   c ,  152   d  are joined by a segment  252   e . In one aspect, the length H 252   c  of the first segment  252   c  is greater than the length H 252   d  of the second segment such that the end face  255   a  seal structure  255  is recessed from the end face  245   c  of the open end cap  245  by a distance D 2 . In such a configuration, the seal structure  255  can be characterized as being fully within the interior area  226   i  defined by the media  226 . 
     The seal structure  255  can be made from a similar material as the end cap  245 , such as a polyurethane material or an injection molded polymeric material. The extension member  252  can be formed from a variety of materials, for example polymeric and metal materials. In one example, the end cap  245 , the extension member  252 , and the seal structure  255  are integrally formed as a single component. 
     Referring to  FIG.  17   , the safety filter cartridge  227  is shown. The safety filter cartridge  227  is similar to filter cartridge  27  in that media  228  and support structure  290  are provided that extend between a first end  280  and a second end  282 , wherein a closed end cap  286  is provided at the second end  282  and an open end cap  284  is provided at the first end  280 . The first end cap  284  includes a support  292  and a secondary seal member  294  having an outwardly directed radial seal surface  296 . As mentioned previously, the support  292  can be formed by the support structure  290 . When molded, the secondary seal member  294  can be provided having an outer section  294   o  on the outside of the support  292  and having an inner section  294   i  on the inside of the support  292 . The secondary seal member  294  can be characterized as having an axial distance or height  294   h  from the bottom  294   b  to the top  294   a  that is sufficient to provide a seal with the filter cartridge baffle  114 . 
     The safety filter cartridge  227  is also provided with an annular seal surface extension member  217 . As shown, the extension member  217  extends between a first end  217   a  and a second end  218   b  and has a height H 217  that is greater than or equal to the height H 242   c  of the first segment  252   c  of the extension member  252 . However, if the second segment  252   d  has a sufficient length, then the height of the extension member  217  can be shorter than the first segment  252   c . As shown, the first end  217   a  is embedded in the first end cap  284  and surrounds the filter media  290 . The extension member can be impervious to gas (e.g. air) passage therethrough. The extension member  217  is provided with a continuous outer surface  217   s  extending between the first and second ends  217   a ,  217   b . The continuous outer surface  217   s  provides a sealing surface against which the sealing surface  255   s  of the main filter cartridge seal structure  255  can form a seal. The extension member  217  can be formed from a polymeric material, such as ABS plastic. The extension member  217  can also be formed as an integral portion of the support structure  290 . In one alternative design, the safety filter media, end cap  286 , and support structure  290  are not provided, and the seal structure  284  and the extension member  217  are provided together as a removable seal surface component. 
     The installed filter cartridges  225 ,  227  can be seen at  FIGS.  15  and  15 A . In these figures, it can be seen that the filter cartridge  227  is installed such that the outer surface  294   o  of the open end cap  284  forms an outwardly directed radial seal against the inner surface  114   b  of the filter cartridge baffle  114 . Once the safety filter cartridge  227  has been installed in this position, the main filter cartridge  225  can be installed such that the safety filter cartridge  227  is received within the interior area  226   i  of the main filter cartridge  225 . The end cap  245  can be provided with a dimension and configuration such that the inner and/or outer radial surfaces  245   a ,  245   b  of the end cap  245  seal against the filter cartridge baffle  114  and housing  2 , respectively. The end cap  245  can also be provided with a dimension and configuration such that no seal radial seal is formed with the filter cartridge baffle  114  and/or the housing  2 . 
     As the filter cartridge  225  is received into the housing  2 , the seal structure  255  will pass over the seal surface extension member  217  on the safety filter cartridge as the filter cartridge  225  eventually reaches its installed position at which point the end face  245   c  of the end cap  245  is brought into contact with the housing  2 . Other options for axial position or constraint of the filter cartridge  225  can also be utilized. As configured the internal diameter D 255  of the seal surface  255   s  is less than the external diameter D 217  of the seal surface  217   s . Accordingly, the seal structure  255  compresses against and forms an inwardly directed radial seal against the extension member outer surface  217   s . Once fully installed, the safety filter cartridge  227  forms a seal with the filter cartridge baffle  114  and the main filter cartridge forms a seal with the safety filter cartridge  225 , thus ensuring a clean air flow path between the inlet  7  and outlet  17  of the housing  2 . This configuration is advantageous in instances where the outer surface  114   c  of the filter cartridge baffle is excessively worn or damaged and/or instances where a main filter cartridge  225  end cap is not compatible for sealing within the housing  2  at some other location. 
     V. Filter Assembly—Fourth Filter Arrangement Embodiment 
     Referring to  FIGS.  19 - 20   , a fourth filter arrangement  301  is shown that can be utilized with the housing  2  depicted in  FIGS.  1  to  4   . The fourth filter arrangement  301  is most similar to the second filter arrangement  101  as each utilizes the same filter cartridge  125 . Accordingly, features of the filter cartridge  125  and its installation within housing  2  need not be further described here. However, in contrast to the second filter arrangement  101 , the fourth filter arrangement  301  additionally includes a safety filter cartridge  327 . The safety filter cartridge  327  is generally similar in design to the safety filter cartridge  27 , but is sized to form a radially outwardly directed seal against the second segment  152   d  of the extension member  152  associated with the filter cartridge  125 . 
     Similar to filter cartridge  27 , the second filter cartridge  327  has media  328  and a support structure  390  that extend between a first end  380  and a second end  382 , wherein an open end cap  384  is provided at the first end and a closed end cap  386  is provided at the second end  382 . The open end cap  384  includes a seal support  392  over which a seal member  394  is disposed. Variations in construction described for filter cartridge  27  are applicable for second filter cartridge  327  and need not be discussed further here. 
     In one aspect, the seal member  394  of the open end cap  384  includes a radially outwardly directed seal surface  396 . As can be most easily seen at  FIG.  20   , the seal surface  396  forms a seal against the second segment  152   d  of the extension member  12  associated with the filter cartridge  125 . As configured, the seal member  394  is provided with an outside diameter D 396  that is slightly greater than an inside diameter D 152   d  such that a slight interference fit exists. Due to the compressibility of the seal member  394 , the seal member  394  will conform to diameter D 152   d  when the filter cartridge  327  is installed within the filter cartridge  125 . 
     In order to install the filter cartridges  125 ,  327  within the housing  2 , the filter cartridge  125  is first installed into the interior space  126   i  of the filter cartridge  327 . This is accomplished by coaxially aligning the filter cartridges  125 ,  327  and then inserting the closed end cap  386  of the filter cartridge  327  through the opening defined by the remote seal structure  155  extending from the open end cap  145  of the filter cartridge  125 . Insertion in this direction continues until the closed end cap  386  of the filter cartridge  327  is brought into contact with the interior surface  146 s of the closed end cap  146  of the filter cartridge  125 . At this installation location, the overall length of the filter cartridge  327  is such that the seal surface  396  is axially aligned with the second segment  152   d  of the extension member  152  of the filter cartridge  152 . Other alignment methods for ensuring that the seal surface  394  is axially aligned with the second segment  152  can be also be used. For example, the extension member  152 , or another part of the filter cartridge  125 , can include a stop member against which a portion (e.g. the seal member  394 ) of the filter cartridge  327  engages. Once the filter cartridge  327  has been installed within the filter cartridge  125 , the cartridges can then be installed together within the housing  2 . Insertion of the combined filter cartridge assembly  125 ,  327  is performed such that the seal surface  155   s  of the remote seal structure  155  associated with the filter cartridge  125  is sealed against the filter cartridge baffle  114  of the housing  2 , as previously described in relation to the filter cartridge  125  in Section III above. 
     VI. Filter Assembly—Fifth Filter Arrangement Embodiment 
     Referring to  FIGS.  21 - 22   , a fifth filter arrangement  401  is shown that can be utilized with the housing  2  depicted in  FIGS.  1  to  4   . The fourth filter arrangement  301  is most similar to the first filter arrangement  1  as each utilizes the same filter cartridge  25 . Accordingly, features of the filter cartridge  25  and its installation within housing  2  need not be further described here. However, in contrast to the first filter arrangement  1 , the fifth filter arrangement  401  combines the safety filter cartridge  27  and a modified version of the seal surface component  17  into a single assembly  427 . 
     Similar to filter cartridge  27 , the filter cartridge  427  has media  428  and a support structure  490  that extend between a first end  480  and a second end  482 , wherein an open end cap  484  is provided at the first end and a closed end cap  486  is provided at the second end  482 . The open end cap  484  includes a seal support  492  over which a seal member  494  is disposed. Variations in construction described for filter cartridge  27  are applicable for second filter cartridge  427  and need not be discussed further here. 
     In one aspect, the open end cap  484  additionally includes a seal surface component  117  having a main body  117   a  (e.g., ring or annular-shaped) extending from a first end  117   b  to a second end  117   c . Between the first end  117   b  and the second end  117   c , the main body  117   a  includes a first extension segment  117   d  and a generally parallel second extension segment  117   e  joined by a connecting portion  117   f  . The first and second extension segments  117   d ,  117   e  are spaced apart such that an annulus  117   g  is formed therebetween. As shown, the second extension segment  117   e  is adjacent the media  128  and/or support structure  190  and is embedded within the material forming the seal support  492 . In one aspect, the first extension part  117   d  defines an outer sealing surface  117   k . In one example, the seal surface component  117  is formed from a material that has a greater hardness than the material used to form the seal surface component  117 . In one example, the seal surface component  117  and the open end cap  484  are formed from a similar material. In one example, the seal surface component  117  and the open end cap  484  are unitarily formed (e.g. via molding) as a single component. In one example, the seal surface component  117  is formed in an independent molding process. In one example, open end cap  484  is simultaneously molded onto the support structure  90 , the media  428 , and the seal surface component  117 . 
     When the filter cartridge  427  is installed into the housing  2 , the filter cartridge baffle  114  of the housing  2  is received into the annulus  117   g  formed between the first and second extension parts  117   d ,  117   e  until the end of the open end cap  484  bottoms out against a surface of the housing  2 . Once the filter cartridge  427  is fully inserted, a seal surface  484   s  of the open end cap  484  seals against the inner surface  114   b  of the filter cartridge baffle  114 . After filter cartridge  427  is installed, the filter cartridge  25  can be inserted into the housing  2  in the same manner as previously described in Section II above. Upon insertion, the seal surface  55   s  associated with the open end cap  45  of filter cartridge  25  seals against the outer sealing surface  117   k  of the seal surface component  117 . 
     VII. Filtration Media and Terminology 
     The particular material chosen for the media is a matter of choice for a selected application. When the filter assembly is an air cleaner, any of a variety of media materials now used in air cleaners can be used with principles according to the present disclosure. 
     The media pack can comprise only media  26 ,  126 ,  226  or the media can be provided with an inner and/or outer liner before installation in the cartridge  25 ,  125 ,  225 . The media can be pleated, nonpleated, depth media, or wave media although additional alternatives are possible. The media can be provided in a variety of configurations including cylindrical and conical, and with a variety of inner and/or outer perimeter definitions, for example circular or oval. Additionally, fluted filter media (media having media ridges) can be used to provide fluid filter constructions in a variety of manners. One well known manner is characterized herein as a z-filter construction. The term “z-filter construction” as used herein, is meant to include (but not be limited) a type of filter construction in which individual ones of corrugated, folded or otherwise formed filter flutes are used to define (typically in combination with facing media) sets of longitudinal, typically parallel, inlet and outlet filter flutes for fluid flow through the media. Some examples of z-filter media are provided in U.S. Pat. Nos. 5,820,646; 5,772,883; 5,902,364; 5,792,247; 5,895,574; 6,210,469; 6,190,432; 6,350,296; 6,179,890; 6,235,195; Des. 399,944; Des. 428,128; Des. 396,098; Des. 398,046; and, Des. 437,401; each of these cited references being incorporated herein by reference. 
     It is noted that although the seal of the arrangements are sometimes characterized as “radial.” However, as a result of the non-circular shape, some of the sealing forces will be directed other than specifically at or away from the central axis X of the cartridge. The seals are nevertheless characterized herein as “radial,” since, in general, the seal surfaces on the cartridge and housing are generally radially directed and the sealing forces are either radially outwardly directed or radially inwardly directed, around the axis X, depending on whether an outwardly or inwardly directed seal surface is involved. Alternately stated, the compression forces are still not axial (i.e. in the longitudinal direction of axis X), but rather are generally radial. There are applications, however, where the seal forces are not aligned directly toward or away from the axis X in each of these non-circular configurations. 
     In more general terms, radial seals comprise seal surfaces that surrounds (directed toward away from) a central axis. That central axis in many instances will comprise a central axis of a filter cartridge around which media is also positioned. However, from alternative arrangements described herein below, it will be understood that a radial seal can be a seal that surrounds an axis that is not also a central axis for the cartridge (by contrast, an axial seal is a seal that is generally aligned with a central axis around which the seal is positioned, typically also, but not necessarily in all instances, a central cartridge axis X). 
     In the general terminology used herein, the various housing seal arrangements depicted can also be characterized as generally comprising a radially directed seal surface, since the seal direction for the various housing seals depicted in the drawings, is generally with a surface of the seal engaging some portion of the housing (be it a portion of an outlet tube or outer portion of the housing, depending on whether which of the two of the housing seals is involved) that can be generally characterized as a “radially directed surface.” In each instance, the surface that actually forms the seal is directed around (and facing toward or away from) a central axis X (typically, also of the cartridge)as opposed to an axial seal which would be generally with seal forces directed in the longitudinal direction of the central axis X. The examples depicted are “radial” seals or “radially” directed seals meaning that the surface of the seal member on the cartridge that will form a seal in engagement with a housing or replaceable sealing surface, is directed either towards or away from a central axis of the cartridge, as opposed to being orthogonal to the axis. In some examples shown, the seals are “outward” radial seal surfaces or “outwardly” directed radial seals since the actual surface of the seal member on the cartridge that will form a seal is generally directed away from a central axis of the cartridge, as opposed as to toward the axis. In some examples shown, the seals are “inward” radial seal surfaces or “inwardly directed” radial seals since the actual surface of the seal member on the cartridge that will form a seal that is generally directed towards a central axis of the cartridge, as opposed to away from the axis. However, many of the principles described herein can be applied in alternate arrangements in which the seal surface on the cartridge that engages the housing to form a seal is directed radially toward the central axis. 
     The radial housing seals described herein can be generally characterized as “non-clamp,” “non-clamping” or “clampless” arrangements or by similar terms. By this it is meant that the seal arrangements typically do not involve the use of a clamp such as a hose clamp or other structure that needs to be tightened in order to provide for a secure seal. Rather, the seals are established by mere installation, with compression of the seal material against a surface of the housing being directed by a cartridge component. 
     The principles described herein can be applied in a variety of filter assemblies. Examples described in which the principles applied to (air) gas filter assemblies. Examples are described include gas/air filters and crankcase ventilation filter assemblies. The principles can be applied to a variety of alternate gas filtration arrangements, in some instances even with liquid filter assemblies. 
     Principles according to the present disclosure relate to interactions between filter cartridges and air cleaner systems, in advantageous manners to achieve certain, selected, desired results discussed below. The filter cartridge would generally include a filter media therein, through which air and other gases pass, during a filtering operation. The media can be of a variety of types and configurations, and can be made from using a variety of materials. For example, pleated media arrangements can be used in cartridges according to the principles of the present disclosure, as discussed below. 
     In this section, examples of some media arrangements that are usable with the techniques described herein are provided. It will be understood, however, that a variety of alternate media types can be used. The choice of media type is generally one of preference for: availability; function in a given situation of application, ease of manufacturability, etc. and the choice is not necessarily specifically related to the overall function of selected ones of various filter cartridge/air cleaner interaction features characterized herein.