Patent Publication Number: US-7713321-B2

Title: Air cleaner arrangements; components thereof; and, methods

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   A claim of priority for the present U.S. application is made to U.S. Provisional application 60/815,794 filed Jun. 22, 2006, to the extent appropriate. In addition the complete disclosure of 60/815,794 is incorporated herein by reference. 
   It is noted that the current application also includes some of the disclosure of U.S. Provisional application 60/760,559 filed Jan. 20, 2006. No claim of priority to the subject of application 60/760,559 is made. 

   FIELD OF THE DISCLOSURE 
   The present disclosure concerns air cleaners for use, for example, for cleaning engine combustion air for vehicles and other equipment. The disclosure provides preferred components, assemblies and methods. 
   BACKGROUND 
   Gas streams often carry particulate material therein. In many instances it is desirable to remove some or all of the particulate material from the gas flow stream. For example, air intake streams to engines for motorized vehicles or power generation equipment often include particulate material therein. The particulate material, should it reach the internal workings of the mechanisms involved, can cause substantial damage. It is therefore preferred, for such systems, to remove the particulate material from the gas flow upstream of the engine or other equipment involved. A variety of air cleaner arrangements have been developed for particulate removal. 
   There has been a general trend for the utilization of air cleaner arrangements that utilize, as a media pack, z-filter media constructions. In general z-filter media constructions can be characterized as comprising fluted media sheet material secured to a facing media sheet material, formed into a media pack configuration. Examples of z-filter arrangements are described in PCT Publication WO 97/40918, published Nov. 6, 1997; U.S. Pat. Nos. 6,190,432 and 6,350,291; PCT application US 04/07927, filed Mar. 17, 2004; U.S. Provisional application 60/532,783, filed Dec. 22, 2003; PCT Publication 03/095068, published Nov. 20, 2003; PCT publication WO 04/007054, published Jan. 22, 2004; PCT publication WO 03/084641, published Oct. 16, 2003; and, U.S. Provisional Application 60/543,804, filed Feb. 11, 2004; the complete disclosures of each of these cited references being incorporated herein by reference. 
   With some arrangements, it has been desired to develop configurations in which the z-filter media is loaded into an air cleaner housing through a side (as opposed to an end) of the housing. Such arrangements are described for example in WO 03/095068, incorporated herein by reference. 
   Selected components described herein are improvements in such air cleaner arrangements as those described in U.S. Provisional Application 60/567,121, filed Apr. 30, 2004; U.S. Provisional Application 60/604,549, filed Aug. 25, 2004; U.S. Provisional Application 60/649,301, filed Feb. 1, 2005; and PCT Publication WO 05/107924, published Nov. 17, 2005. Each of these references is incorporated herein by reference. 
   SUMMARY OF THE DISCLOSURE 
   The present disclosure concerns air cleaners and componentry therefor. A variety of features and component features are described, for air cleaners and their components, including serviceable filter cartridges. Selected features described herein relate to features in an air cleaner housing facilitating installation, alternatively, of different sized primary filter cartridges; and, features of primary filter cartridges that facilitate installation in such housings. 
   It is noted that not all of the features described herein must be incorporated in an arrangement, for the arrangement to have some selected advantage according to the present disclosure. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a fragmentary, schematic, perspective view of z-filter media useable in arrangements according to the present disclosure. 
       FIG. 2  is a schematic, cross-sectional view of a portion of the media depicted in  FIG. 1 . 
       FIG. 3  is a schematic view of examples of various corrugated media definitions. 
       FIG. 4  is a schematic view of a useable process for manufacturing media according to the present disclosure. 
       FIG. 5  is a cross-sectional view of an optional end dart for media flutes useable in arrangements according to the present disclosure. 
       FIG. 6  is a top perspective view of an air cleaner assembly having features according to the present disclosure. 
       FIG. 7  is a side elevational view of the air cleaner depicted in  FIG. 6 . 
       FIG. 8  is a top plan view of the air cleaner depicted in  FIG. 6 , with a modified inlet aperture and outlet aperture arrangement. 
       FIG. 9  is a perspective view of the air cleaner of  FIG. 6 , with a modified air outlet arrangement and with an access cover removed for viewing an interior of a housing thereof. 
       FIG. 10  is a side elevational view of the arrangement of  FIG. 9 . 
       FIG. 11  is a top plan view of a first, relatively long, filter cartridge configured for installation in the air cleaner arrangements of  FIGS. 1-10 ;  FIG. 11  being from a view point of a top plan view as the element would appear during a step of insertion. 
       FIG. 12  is a side elevational view of the filter cartridge of  FIG. 11 ;  FIG. 12  depicting the cartridge in a side plan view toward a side facing an installer, during installation. 
       FIG. 13  is a side perspective view of the filter cartridge of  FIGS. 11 and 12  installed in an air cleaner housing generally according to  FIGS. 6-10  prior to positioning of an access cover on the air cleaner housing. 
       FIG. 14  is a top plan view generally according to  FIG. 13 , with a modified inlet cover. 
       FIG. 15  is a side elevational view of the partial assembly of  FIGS. 13 and 14 . 
       FIG. 15A  is an enlarged fragmentary view of a portion of  FIG. 15 . 
       FIG. 16  is a cross-sectional view of the assembly of  FIG. 15 , taken with the access cover replaced and generally along line  16 - 16 ,  FIG. 15 . 
       FIG. 17  is a cross-sectional view analogous to  FIG. 16 , and taken along line  17 - 17 ,  FIG. 15 , depicting the air cleaner housing with: the filter cartridge removed; the access cover in place; and a modified inlet section and outlet section. 
       FIG. 18  is a top plan view of a second, shorter, filter cartridge configured for installation in the air cleaner housing of  FIGS. 6-10 ; the view of  FIG. 18  being a top plan view of the cartridge oriented for a step of installation. 
       FIG. 19  is a side elevational view of the cartridge depicted in  FIG. 18 ;  FIG. 19  depicting a view point toward an installer. 
       FIG. 20  is a side perspective view depicting the cartridge of  FIGS. 18 and 19  installed in a housing generally in accord with  FIGS. 6-10  but without an access cover on the housing. 
       FIG. 21  is a top plan view of the assembly of  FIG. 20 , with a modified inlet and without an access cover in place. 
       FIG. 22  is a side elevational view of the assemblies of  FIGS. 20-21 , with an access cover in place. 
       FIG. 23  is an enlarged fragmentary view of a portion of  FIG. 20 . 
       FIG. 24  is a cross-sectional view of the assembly of  FIGS. 20-22 , depicted with an access cover in position and from a cross-sectional view generally in accord with line  16 - 16 ,  FIG. 15 , but depicting the assembly with the shorter filter cartridge of  FIGS. 19 and 20 , in place. 
       FIG. 25  is a schematic depiction of a modification in the air cleaner of  FIG. 6 , for a first side inlet. 
       FIG. 26  is a schematic view of an assembly generally in accord with  FIG. 25 , with a second modified side inlet. 
       FIG. 27  is a schematic view of an air cleaner according to  FIG. 7  depicted within an engine compartment of a vehicle. 
       FIG. 28  is an enlarged fragmentary cross-sectional view of a portion of a filter cartridge useable in arrangements according to the present disclosure. 
       FIG. 29  is a cross-sectional view analogous to  FIG. 28 , depicting a first alternate seal arrangement. 
       FIG. 30  is a fragmentary cross-sectional view depicting a second alternate seal arrangement. 
       FIG. 31  is an enlarged fragmentary cross-sectional view depicting a third alternate seal arrangement. 
       FIG. 32  is a view analogous to  FIG. 13 , but depicting an alternate dual inlet. 
       FIG. 33  is a schematic top plan view analogous to  FIG. 11 , of an alternate filter cartridge installable in a housing incorporating selected principles described herein. 
       FIG. 34  is a schematic side elevational view of the cartridge of  FIG. 33 . 
       FIG. 35  is an outlet end elevational view of the cartridge depicted in  FIGS. 33 and 34 . 
       FIG. 36  is an inlet end elevational view of the cartridge depicted in  FIGS. 33-35 . 
       FIG. 37  is a schematic side cross-sectional view analogous to  FIG. 10  depicting a housing for receipt of the cartridge of  FIGS. 33-36 , with an access cover removed; in  FIG. 37  the air cleaner housing depicted being shown with alternate inlet and outlet configurations to those shown in  FIG. 10 . 
       FIG. 38  is a schematic view analogous to  FIG. 37 , with the cartridge of  FIG. 33-36  installed and also depicted in cross-section. 
       FIG. 39  is an enlarged fragmentary cross-sectional view of a portion of  FIG. 38 , taken along line  39 - 39  thereof. 
       FIG. 40  is an enlarged, schematic, fragmentary view of a portion of  FIG. 39 . 
       FIG. 41  is an enlarged, schematic, fragmentary cross-sectional view of a portion of  FIG. 38 . 
   

   DETAILED DESCRIPTION 
   I. Z-Filter Media Configurations, Generally 
   Fluted filter media can be used to provide fluid filter constructions in a variety of manners. One well known manner is as a z-filter construction. The term “z-filter construction” as used herein, is meant to refer to a filter construction in which individual ones of corrugated, folded or otherwise formed filter flutes are used to define sets of longitudinal, filter flutes for fluid flow through the media; the fluid flowing along the length of the flutes between opposite inlet and outlet flow ends (or flow faces) of 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 fifteen cited references being incorporated herein by reference. 
   One type of z-filter media, utilizes two specific media components joined together, to form the media construction. The two components are: (1) a fluted (typically corrugated) media sheet; and, (2) a facing media sheet. The facing media sheet is typically non-corrugated, however it can be corrugated, for example perpendicularly to the flute direction as described in U.S. provisional 60/543,804, filed Feb. 11, 2004, incorporated herein by reference. 
   The fluted (typically corrugated) media sheet and the facing media sheet, together, are used to define media having parallel inlet and outlet flutes. In some instances, the fluted sheet and non-fluted sheet are secured together and are then coiled to form a z-filter media construction. Such arrangements are described, for example, in U.S. Pat. Nos. 6,235,195 and 6,179,890, each of which is incorporated herein by reference. In certain other arrangements, some non-coiled sections of fluted media secured to flat media, are stacked on one another, to create a filter construction. An example of this is described in FIG. 11 of 5,820,646, incorporated herein by reference. 
   For specific examples described herein below, coiled arrangements are depicted, although many of the principles can be applied with stacked arrangements. 
   Typically, coiling of the fluted sheet/facing sheet combination around itself, to create a coiled media pack, is conducted with the facing sheet directed outwardly. Some techniques for coiling are described in U.S. provisional application 60/467,521, filed May 2, 2003 and PCT Application US 04/07927, filed Mar. 17, 2004, each of which is incorporated herein by reference. The resulting coiled arrangement generally has, as the outer surface of the media pack, a portion of the facing sheet, as a result. 
   The term “corrugated” used herein to refer to structure in media, is meant to refer to a flute structure resulting from passing the media between two corrugation rollers, i.e., into a nip or bite between two rollers, each of which has surface features appropriate to cause a corrugation affect in the resulting media. The term “corrugation” is not meant to refer to flutes that are formed by techniques not involving passage of media into a bite between corrugation rollers. However, the term “corrugated” is meant to apply even if the media is further modified or deformed after corrugation, for example by the folding techniques described in PCT WO 04/007054, published Jan. 22, 2004, incorporated herein by reference. 
   Corrugated media is a specific form of fluted media. Fluted media is media which has individual flutes (for example formed by corrugating or folding) extending thereacross. 
   Serviceable filter element or filter cartridge configurations utilizing z-filter media are sometimes referred to as “straight through flow configurations” or by variants thereof. In general, in this context what is meant is that the serviceable filter elements generally have an inlet flow end (or face) and an opposite exit flow end (or face), with flow entering and exiting the filter cartridge in generally the same straight through direction. (The term “straight through flow configuration” disregards, for this definition, air flow that passes out of the media pack through the outermost wrap of facing media.) The term “serviceable” in this context is meant to refer to a media containing filter cartridge that is periodically removed and replaced from a corresponding air cleaner. In some instances, each of the inlet flow end and outlet flow end will be generally flat or planar, with the two parallel to one another. However, variations from this, for example non-planar faces are possible. 
   A straight through flow configuration (especially for a coiled media pack) is, for example, in contrast to serviceable filter cartridges such as cylindrical pleated filter cartridges of the type shown in U.S. Pat. No. 6,039,778, incorporated herein by reference, in which the flow generally makes a turn as its passes through the serviceable cartridge. That is, in a U.S. Pat. No. 6,039,778 filter, the flow enters the cylindrical filter cartridge through a cylindrical side, and then turns to exit through an end face (in forward-flow systems). In a typical reverse-flow system, the flow enters the serviceable cylindrical cartridge through an end face and then turns to exit through a side of the cylindrical filter cartridge. An example of such a reverse-flow system is shown in U.S. Pat. No. 5,613,992, incorporated by reference herein. 
   The term “z-filter media construction” and variants thereof as used herein, without more, is meant to refer to any or all of: a web of corrugated or otherwise fluted media secured to (facing) media with appropriate sealing to inhibit air flow from one flow face to another without filtering passage through the filter media; and/or, such a media coiled or otherwise constructed or formed into a three dimensional network of flutes; and/or, a filter construction including such media. In many arrangements, the z-filter media constructions configured for the formation of a network of inlet and outlet flutes, inlet flutes being open at a region adjacent an inlet face and being closed at a region adjacent an outlet face; and, outlet flutes being closed adjacent an inlet face and being open adjacent an outlet face. However, alternative z-filter media arrangements are possible, see for example US 2006/0091084 A1, published May 4, 2006, incorporated herein by reference; also comprising flutes extending between opposite flow faces, with a seal arrangement to prevent flow of unfiltered air through the media pack. 
   In  FIG. 1  herein, an example of media  1  useable in z-filter media is shown. The media  1  is formed from a fluted (corrugated) sheet  3  and a facing sheet  4 . 
   In general, the corrugated sheet  3 ,  FIG. 1  is of a type generally characterized herein as having a regular, curved, wave pattern of flutes or corrugations  7 . The term “wave pattern” in this context, is meant to refer to a flute or corrugated pattern of alternating troughs  7   b  and ridges  7   a . The term “regular” in this context is meant to refer to the fact that the pairs of troughs and ridges ( 7   b ,  7   a ) alternate with generally the same repeating corrugation (or flute) shape and size. (Also, typically in a regular configuration each trough  7   b  is substantially an inverse of each ridge  7   a .) The term “regular” is thus meant to indicate that the corrugation (or flute) pattern comprises troughs and ridges with each pair (comprising an adjacent trough and ridge) repeating, without substantial modification in size and shape of the corrugations along at least 70% of the length of the flutes. The term “substantial” in this context, refers to a modification resulting from a change in the process or form used to create the corrugated or fluted sheet, as opposed to minor variations from the fact that the media sheet  3  is flexible. With respect to the characterization of a repeating pattern, it is not meant that in any given filter construction, an equal number of ridges and troughs is necessarily present. The media  1  could be terminated, for example, between a pair comprising a ridge and a trough, or partially along a pair comprising a ridge and a trough. (For example, in  FIG. 1  the media  1  depicted in fragmentary has eight complete ridges  7   a  and seven complete troughs  7   b .) Also, the opposite flute ends (ends of the troughs and ridges) may vary from one another. Such variations in ends are disregarded in these definitions, unless specifically stated. That is, variations in the ends of flutes are intended to be covered by the above definitions. 
   In the context of the characterization of a “curved” wave pattern of corrugations, the term “curved” is meant to refer to a corrugation pattern that is not the result of a folded or creased shape provided to the media, but rather the apex  7   a  of each ridge and the bottom  7   b  of each trough is formed along a radiused curve. Although alternatives are possible, a typical radius for such z-filter media would be at least 0.25 mm and typically would be not more than 3 mm. (Media that is not curved, by the above definition, can also be useable.) 
   An additional characteristic of the particular regular, curved, wave pattern depicted in  FIG. 1 , for the corrugated sheet  3 , is that at approximately a midpoint  30  between each trough and each adjacent ridge, along most of the length of the flutes  7 , is located a transition region where the curvature inverts. For example, viewing back side or face  3   a ,  FIG. 1 , trough  7   b  is a concave region, and ridge  7   a  is a convex region. Of course when viewed toward front side or face  3   b , trough  7   b  of side  3   a  forms a ridge; and, ridge  7   a  of face  3   a , forms a trough. (In some instances, region  30  can be a straight segment, instead of a point, with curvature inverting at ends of the segment  30 .) 
   A characteristic of the particular regular, curved, wave pattern corrugated sheet  3  shown in  FIG. 1 , is that the individual corrugations are generally straight. By “straight” in this context, it is meant that through at least 70% (typically at least 80%) of the length between edges  8  and  9 , the ridges  7   a  and troughs  7   b  do not change substantially in cross-section. The term “straight” in reference to corrugation pattern shown in  FIG. 1 , in part distinguishes the pattern from the tapered flutes of corrugated media described in FIG. 1 of WO 97/40918 and PCT Publication WO 03/47722, published Jun. 12, 2003, incorporated herein by reference. The tapered flutes of FIG. 1 of WO 97/40918, for example, would be a curved wave pattern, but not a “regular” pattern, or a pattern of straight flutes, as the terms are used herein. 
   Referring to the present  FIG. 1  and as referenced above, the media  1  has first and second opposite edges  8  and  9 . When the media  1  is coiled and formed into a media pack, in general edge  9  will form an inlet end for the media pack and edge  8  an outlet end, although an opposite orientation is possible. 
   In the example shown, adjacent edge  8  is provided sealant, in this instance in the form of a sealant bead  10 , sealing the corrugated (fluted) sheet  3  and the facing sheet  4  together. Bead  10  will sometimes be referred to as a “single facer” bead, since it is a bead between the corrugated sheet  3  and facing sheet  4 , which forms the single facer or media strip  1 . Sealant bead  10  seals closed individual flutes  11  adjacent edge  8 , to passage of air therefrom. 
   In the example shown, adjacent edge  9 , is provided sealant, in this instance in the form of a seal bead  14 . Seal bead  14  generally closes flutes  15  to passage of unfiltered fluid therein, adjacent edge  9 . Bead  14  would typically be applied as the media  1  is coiled about itself, with the corrugated sheet  3  directed to the inside. Thus, bead  14  will form a seal between a back side  17  of facing sheet  4 , and side  18  of the corrugated sheet  3 . The bead  14  will sometimes be referred to as a “winding bead” since it is typically applied, as the strip  1  is coiled into a coiled media pack. If the media  1  is cut in strips and stacked, instead of coiled, bead  14  would be a “stacking bead.” 
   Referring to  FIG. 1 , once the media  1  is incorporated into a media pack, for example by coiling or stacking, it can be operated as follows. First, air in the direction of arrows  12 , would enter open flutes  11  adjacent end  9 . Due to the closure at end  8 , by bead  10 , the air would pass through the media shown by arrows  13 . It could then exit the media pack, by passage through open ends  15   a  of the flutes  15 , adjacent end  8  of the media pack. Of course operation could be conducted with air flow in the opposite direction. 
   In more general terms, z-filter media comprises fluted filter media secured to facing filter media, and configured in a media pack of flutes extending between first and second opposite flow faces. A sealant arrangement is provided within the media pack, to ensure that air entering flutes at a first upstream edge cannot exit the media pack from a downstream edge, without filtering passage through the media. 
   For the particular arrangement shown herein in  FIG. 1 , the parallel corrugations  7   a ,  7   b  are generally straight completely across the media, from edge  8  to edge  9 . Straight flutes or corrugations can be deformed or folded at selected locations, especially at ends. Modifications at flute ends for closure are generally disregarded in the above definitions of “regular,” “curved” and “wave pattern.” 
   Z-filter constructions which do not utilize straight, regular curved wave pattern corrugation (flute) shapes are known. For example in Yamada et al. U.S. Pat. No. 5,562,825 corrugation patterns which utilize somewhat semicircular (in cross section) inlet flutes adjacent narrow V-shaped (with curved sides) exit flutes are shown (see FIGS. 1 and 3, of U.S. Pat. No. 5,562,825). In Matsumoto, et al. U.S. Pat. No. 5,049,326 circular (in cross-section) or tubular flutes defined by one sheet having half tubes attached to another sheet having half tubes, with flat regions between the resulting parallel, straight, flutes are shown, see FIG. 2 of Matsumoto &#39;326. In Ishii, et al. U.S. Pat. No. 4,925,561 (FIG. 1) flutes folded to have a rectangular cross section are shown, in which the flutes taper along their lengths. In WO 97/40918 (FIG. 1), flutes or parallel corrugations which have a curved, wave patterns (from adjacent curved convex and concave troughs) but which taper along their lengths (and thus are not straight) are shown. Also, in WO 97/40918 flutes which have curved wave patterns, but with different sized ridges and troughs, are shown. 
   In general, the filter media is a relatively flexible material, typically a non-woven fibrous material (of cellulose fibers, synthetic fibers or both) often including a resin therein, sometimes treated with additional materials. Thus, it can be conformed or configured into the various corrugated patterns, without unacceptable media damage. Also, it can be readily coiled or otherwise configured for use, again without unacceptable media damage. Of course, it must be of a nature such that it will maintain the required corrugated configuration, during use. 
   In the corrugation process, an inelastic deformation is caused to the media. This prevents the media from returning to its original shape. However, once the tension is released the flute or corrugations will tend to spring back, recovering only a portion of the stretch and bending that has occurred. The facing sheet is sometimes tacked to the fluted sheet, to inhibit this spring back in the corrugated sheet. 
   Also, typically, the media contains a resin. During the corrugation process, the media can be heated to above the glass transition point of the resin. When the resin then cools, it will help to maintain the fluted shapes. 
   The media of the corrugated sheet  3  facing sheet  4  or both, can be provided with a fine fiber material on one or both sides thereof, for example in accord with U.S. Pat. No. 6,673,136, incorporated herein by reference. 
   An issue with respect to z-filter constructions relates to closing of the individual flute ends. Typically a sealant or adhesive is provided, to accomplish the closure. As is apparent from the discussion above, in typical z-filter media, especially that which uses straight flutes as opposed to tapered flutes, large sealant surface areas (and volume) at both the upstream end and the downstream end are needed. High quality seals at these locations are critical to proper operation of the media structure that results. The high sealant volume and area, creates issues with respect to this. 
   Still referring to  FIG. 1 , at  20  tack beads are shown positioned between the corrugated sheet  3  and facing sheet  4 , securing the two together. The tack beads can be for example, discontinuous lines of adhesive. The tack beads can also be points in which the media sheets are welded together. 
   From the above, it will be apparent that the corrugated sheet  3  is typically not secured continuously to the facing sheet, along the troughs or ridges where the two adjoin. Thus, air can flow between adjacent inlet flutes, and alternately between the adjacent outlet flutes, without passage through the media. However air which has entered in inlet flute cannot exit from an outlet flute, without passing through at least one sheet of media, with filtering. 
   Attention is now directed to  FIG. 2 , in which a z-filter media construction  40  utilizing a fluted (in this instance regular, curved, wave pattern corrugated) sheet  43 , and a non-corrugated flat, facing, sheet  44 , is depicted. The distance D 1 , between points  50  and  51 , defines the extension of flat media  44  in region  52  underneath a given corrugated flute  53 . The length D 2  of the arcuate media for the corrugated flute  53 , over the same distance D 1  is of course larger than D 1 , due to the shape of the corrugated flute  53 . For a typical regular shaped media used in fluted filter applications, the linear length D 2  of the media  53  between points  50  and  51  will generally be at least 1.2 times D 1 . Typically, D 2  would be within a range of 1.2-2.0, inclusive. One particularly convenient arrangement for air filters has a configuration in which D 2  is about 1.25-1.35×D 1 . Such media has, for example, been used commercially in Donaldson Powercore™ Z-filter arrangements. Herein the ratio D 2 /D 1  will sometimes be characterized as the flute/flat ratio or media draw for the corrugated media. 
   In the corrugated cardboard industry, various standard flutes have been defined. For example the standard E flute, standard X flute, standard B flute, standard C flute and standard A flute.  FIG. 3 , attached, in combination with Table A below provides definitions of these flutes. 
   Donaldson Company, Inc., (DCI) the assignee of the present disclosure, has used variations of the standard A and standard B flutes, in a variety of z-filter arrangements. These flutes are also defined in Table A and  FIG. 3 . 
   
     
       
         
             
           
             
               TABLE A 
             
             
                 
             
             
               (Flute definitions for FIG. 3) 
             
             
                 
             
           
          
             
                 
             
          
         
         
             
             
             
          
             
                 
               DCI A Flute: 
               Flute/flat = 1.52:1; The Radii (R) are as follows: 
             
             
                 
                 
               R1000 = .0675 inch (1.715 mm); 
             
             
                 
                 
               R1001 = .0581 inch (1.476 mm); 
             
             
                 
                 
               R1002 = .0575 inch (1.461 mm); 
             
             
                 
                 
               R1003 = .0681 inch (1.730 mm); 
             
             
                 
               DCI B Flute: 
               Flute/flat = 1.32:1; The Radii (R) are as follows: 
             
             
                 
                 
               R1004 = .0600 inch (1.524 mm); 
             
             
                 
                 
               R1005 = .0520 inch (1.321 mm); 
             
             
                 
                 
               R1006 = .0500 inch (1.270 mm); 
             
             
                 
                 
               R1007 = .0620 inch (1.575 mm); 
             
             
                 
               Std. E Flute: 
               Flute/flat = 1.24:1; The Radii (R) are as follows: 
             
             
                 
                 
               R1008 = .0200 inch (.508 mm); 
             
             
                 
                 
               R1009 = .0300 inch (.762 mm); 
             
             
                 
                 
               R1010 = .0100 inch (.254 mm); 
             
             
                 
                 
               R1011 = .0400 inch (1.016 mm); 
             
             
                 
               Std. X Flute: 
               Flute/flat = 1.29:1; The Radii (R) are as follows: 
             
             
                 
                 
               R1012 = .0250 inch (.635 mm); 
             
             
                 
                 
               R1013 = .0150 inch (.381 mm); 
             
             
                 
               Std. B Flute: 
               Flute/flat = 1.29:1; The Radii (R) are as follows: 
             
             
                 
                 
               R1014 = .0410 inch (1.041 mm); 
             
             
                 
                 
               R1015 = .0310 inch (.7874 mm); 
             
             
                 
                 
               R1016 = .0310 inch (.7874 mm); 
             
             
                 
               Std. C Flute: 
               Flute/flat = 1.46:1; The Radii (R) are as follows: 
             
             
                 
                 
               R1017 = .0720 inch (1.829 mm); 
             
             
                 
                 
               R1018 = .0620 inch (1.575 mm); 
             
             
                 
               Std. A Flute: 
               Flute/flat = 1.53:1; The Radii (R) are as follows: 
             
             
                 
                 
               R1019 = .0720 inch (1.829 mm); 
             
             
                 
                 
               R1020 = .0620 inch (1.575 mm). 
             
             
                 
                 
             
          
         
       
     
   
   Of course other, standard, flutes definitions from the corrugated box industry are known. 
   In general, standard flute configurations from the corrugated box industry can be used to define corrugation shapes or approximate corrugation shapes for corrugated media. Comparisons above between the DCI A flute and DCI B flute, and the corrugation industry standard A and standard B flutes, indicate some convenient variations. 
   II. Manufacture of Coiled Media Configurations Using Fluted Media, Generally 
   In  FIG. 4 , one example of a manufacturing process for making a media strip corresponding to strip  1 ,  FIG. 1  is shown. In general, facing sheet  64  and the fluted (corrugated) sheet  66  having flutes  68  are brought together to form a media web  69 , with an adhesive bead located therebetween at  70 . The adhesive bead  70  will form a single facer bead  10 ,  FIG. 1 . An optional darting process occurs at station  71  to form center darted section  72  located mid-web. The z-filter media or Z-media strip  74  can be cut or slit at  75  along the bead  70  to create two pieces  76 ,  77  of z-filter media  74 , each of which has an edge with a strip of sealant (single facer bead) extending between the corrugating and facing sheet. Of course, if the optional darting process is used, the edge with a strip of sealant (single facer bead) would also have a set of flutes darted at this location. 
   Techniques for conducting a process as characterized with respect to  FIG. 4  are described in PCT WO 04/007054, published Jan. 22, 2004 incorporated herein by reference. 
   Still in reference to  FIG. 4 , before the z-filter media  74  is put through the darting station  71  and eventually slit at  75 , it must be formed. In the schematic shown in  FIG. 4 , this is done by passing a sheet of media  92  through a pair of corrugation rollers  94 ,  95 . In the schematic shown in  FIG. 4 , the sheet of media  92  is unrolled from a roll  96 , wound around tension rollers  98 , and then passed through a nip or bite  102  between the corrugation rollers  94 ,  95 . The corrugation rollers  94 ,  95  have teeth  104  that will give the general desired shape of the corrugations after the flat sheet  92  passes through the nip  102 . After passing through the nip  102 , the sheet  92  becomes corrugated across the machine direction and is referenced at  66  as the corrugated sheet. The corrugated sheet  66  is then secured to facing sheet  64 . (The corrugation process may involve heating the media, in some instances.) 
   Still in reference to  FIG. 4 , the process also shows the facing sheet  64  being routed to the darting process station  71 . The facing sheet  64  is depicted as being stored on a roll  106  and then directed to the corrugated sheet  66  to form the Z-media  74 . The corrugated sheet  66  and the facing sheet  64  would typically be secured together by adhesive or by other means (for example by sonic welding). 
   Referring to  FIG. 4 , an adhesive line  70  is shown used, to secure corrugated sheet  66  and facing sheet  64  together, as the sealant bead. Alternatively, the sealant bead for forming the facing bead could be applied as shown as  70   a . If the sealant is applied at  70   a , it may be desirable to put a gap in the corrugation roller  95 , and possibly in both corrugation rollers  94 ,  95 , to accommodate the bead  70   a.    
   Of course the equipment of  FIG. 4  can be modified to provide for the tack beads  20 , if desired. 
   The type of corrugation provided to the corrugated media is a matter of choice, and will be dictated by the corrugation or corrugation teeth of the corrugation rollers  94 ,  95 . One useful corrugation pattern will be a regular curved wave pattern corrugation, of straight flutes, as defined herein above. A typical regular curved wave pattern used, would be one in which the distance D 2 , as defined above, in a corrugated pattern is at least 1.2 times the distance D 1  as defined above. In example applications, typically D 2 =1.25−1.35×D 1 , although alternatives are possible. In some instances the techniques may be applied with curved wave patterns that are not “regular,” including, for example, ones that do not use straight flutes. Also, variations from the curved wave patterns shown, are possible. 
   As described, the process shown in  FIG. 4  can be used to create the center darted section  72 .  FIG. 5  shows, in cross-section, one of the flutes  68  after darting and slitting. 
   A fold arrangement  118  can be seen to form a darted flute  120  with four creases  121   a ,  121   b ,  121   c ,  121   d . The fold arrangement  118  includes a flat first layer or portion  122  that is secured to the facing sheet  64 . A second layer or portion  124  is shown pressed against the first layer or portion  122 . The second layer or portion  124  is preferably formed from folding opposite outer ends  126 ,  127  of the first layer or portion  122 . 
   Still referring to  FIG. 5 , two of the folds or creases  121   a ,  121   b  will generally be referred to herein as “upper, inwardly directed” folds or creases. The term “upper” in this context is meant to indicate that the creases lie on an upper portion of the entire fold  120 , when the fold  120  is viewed in the orientation of  FIG. 5 . The term “inwardly directed” is meant to refer to the fact that the fold line or crease line of each crease  121   a ,  121   b , is directed toward the other. 
   In  FIG. 5 , creases  121   c ,  121   d , will generally be referred to herein as “lower, outwardly directed” creases. The term “lower” in this context refers to the fact that the creases  121   c ,  121   d  are not located on the top as are creases  121   a ,  121   b , in the orientation of  FIG. 5 . The term “outwardly directed” is meant to indicate that the fold lines of the creases  121   c ,  121   d  are directed away from one another. 
   The terms “upper” and “lower” as used in this context are meant specifically to refer to the fold  120 , when viewed from the orientation of  FIG. 5 . That is, they are not meant to be otherwise indicative of direction when the fold  120  is oriented in an actual product for use. 
   Based upon these characterizations and review of  FIG. 5 , it can be seen that a preferred regular fold arrangement  118  according to  FIG. 5  in this disclosure is one which includes at least two “upper, inwardly directed, creases.” These inwardly directed creases are unique and help provide an overall arrangement in which the folding does not cause a significant encroachment on adjacent flutes. 
   A third layer or portion  128  can also be seen pressed against the second layer or portion  124 . The third layer or portion  128  is formed by folding from opposite inner ends  130 ,  131  of the third layer  128 . 
   Another way of viewing the fold arrangement  118  is in reference to the geometry of alternating ridges and troughs of the corrugated sheet  66 . The first layer or portion  122  is formed from an inverted ridge. The second layer or portion  124  corresponds to a double peak (after inverting the ridge) that is folded toward, and in preferred arrangements, folded against the inverted ridge. 
   Techniques for providing the optional dart described in connection with  FIG. 5 , in a preferred manner, are described in PCT WO 04/007054, incorporated herein by reference. Techniques for coiling the media, with application of the winding bead, are described in PCT application US 04/07927, filed Mar. 17, 2004 and incorporated herein by reference. 
   Techniques described herein are particularly well adapted for use in media packs that result from coiling a single sheet comprising a corrugated sheet/facing sheet combination, i.e., a “single facer” strip. Certain of the techniques can be applied with arrangements that, instead of being formed by coiling, are formed from a plurality of strips of single facer. 
   Coiled media pack arrangements can be provided with a variety of peripheral perimeter definitions. In this context the term “peripheral, perimeter definition” and variants thereof, is meant to refer to the outside perimeter shape defined, looking at either the inlet end or the outlet end of the media pack. Typical shapes are circular as described in PCT WO 04/007054 and PCT application US 04/07927. Other useable shapes are obround, some examples of obround being oval shape. In general oval shapes have opposite curved ends attached by a pair of opposite sides. In some oval shapes, the opposite sides are also curved. In other oval shapes, sometimes called racetrack shapes, the opposite sides are generally straight. Racetrack shapes are described for example in PCT WO 04/007054 and PCT application US 04/07927. 
   Another way of describing the peripheral or perimeter shape is by defining the perimeter resulting from taking a cross-section through the media pack in a direction orthogonal to the winding access of the coil. 
   Opposite flow ends or flow faces of the media pack can be provided with a variety of different definitions. In many arrangements, the ends are generally flat and perpendicular to one another. In other arrangements, the end faces include tapered, coiled, stepped portions which can either be defined to project axially outwardly from an axial end of the side wall of the media pack; or, to project axially inwardly from an end of the side wall of the media pack. 
   The flute seals (for example from the single facer bead, winding bead or stacking bead) can be formed from a variety of materials. In various ones of the cited and incorporated references, hot melt or polyurethane seals are described as possible for various applications. 
   III. Improved Air Cleaner Arrangements Utilizing Z-Filter Media 
   A. General Air Cleaner Features. 
   The reference numeral  200 ,  FIG. 6 , generally depicts an air cleaner according to the present disclosure. The air cleaner  200  comprises a housing  201  having an inlet section  202 , an outlet section  203  and a central region  205  positioned therebetween. The central region  205  includes a removable access cover  206 . 
   In general, the central region  205  defines an installation and receiving space for a primary air filter cartridge or cartridge arrangement, which is serviceable, removable and replaceable. During air cleaner use, air to be filtered: (a) enters the air cleaner  200  through inlet arrangement  210  in inlet section  202 ; (b) is directed through a primary filter cartridge received within central region  205 ; and, then, (c) the resulting filtered air is passed into outlet section  203 , from which it passes through outlet arrangement  211  into appropriate ductwork into an engine air intake. 
   The particular air cleaner  200  depicted, would typically be manufactured in modular pieces comprising: the inlet section  202 ; the outlet section  203 ; and, the central section  205 , comprising base  214  and separable access cover  206 . In a typical approach, the parts  202 ,  203 ,  206  and  214  can be molded from plastic utilizing a variety of molding techniques. However, alternate materials and approaches to construction can be used with the principles described herein. 
   Herein the base  214  will sometimes be referred to as a “primary filter cartridge receiving section.” The term “primary filter cartridge” in this context, is meant to refer to a serviceable filter cartridge including z-filter media in accord with the general descriptions above, positioned within housing  201  during use. The term “primary filter cartridge” is not meant to include within its scope, any separate safety filters that may be positioned within the housing  201 . The term “primary filter cartridge receiving section” is meant to refer to the portion of base  214 , in which the primary filter cartridge is positioned, during installation. It is noted that in some instances portions of the primary filter cartridge, during installation, can project out of the primary filter cartridge receiving section  214 , for example into cover  206  and as described below, portions of a seal arrangement on the primary filter cartridge may project into the outlet section  203 . 
   As a result of the modular construction, the air cleaner  200  of  FIG. 6  can be provided with a variety of options including, for example: mounting of a modified outlet section  203  for example configured such that outlet arrangement  211  is a tube that points in an opposite direction from that shown in  FIG. 6 ; and, replacement of inlet section  202  with an alternate inlet section modified, for example, to receive air flow from an alternate direction and/or to have a different inlet configuration. Examples of these possibilities are discussed briefly herein below and are shown in various drawings. 
   In a typical arrangement, once the modular housing assembly  201  is created, the inlet section  202  and outlet section  203  would not be removed from the base  214 . Thus, typically these components will typically be provided with an interference fit or be sonically welded or otherwise secured together. 
   The access cover  206  is configured to removable from a remainder of housing  201 , for service access to an interior of the housing  201 . In the example shown, the access cover  206  is secured in place by over center latches  216 . Such latches  216  would typically be manufactured from metal wire and then would be mounted on latch mounts  217  molded into the access cover  206 . 
   Still referring to  FIG. 6 , it is noted that for the particular air cleaner  200  depicted, inlet  210  is provided with a flexible bellows  220 . The bellows  220  is an option, and is configured to be engaged by a hood of a vehicle, such as a truck, being closed over the air cleaner  200 , such that an inlet duct arrangement built into the hood engages the bellows  220  for directing air to inlet  210 . An example is shown schematically in  FIG. 27 , discussed below. 
   The air cleaner  200  depicted in  FIGS. 6 and 27 , is depicted in an orientation it would typically have when installed, typically on top of an engine block and under the hood of a truck. That is, although alternatives are possible, in many uses, cover  206  would be removable laterally from a side of housing  201 , instead of being lifted upwardly when removed. 
   Attention is now directed to  FIG. 7 . In  FIG. 7  air cleaner  200  is depicted in a side elevational view; the view being toward access cover  206 . It is noted that in  FIG. 7  the outlet section  203  is depicted mounted rotated 180° relative to  FIG. 6 , such that the outlet arrangement  211  (not viewable in  FIG. 7 ) points away from the viewer. This is indicative of certain options provided by the modular construction, as suggested above. 
   Referring still to  FIG. 7 , at  225  mounting legs or pads are provided, for securing the air cleaner  200  in position, or within equipment such as a vehicle. It is noted that mounting pads can be provided at various locations on the housing  201 , to allow for alternate orientations of the mounting of the air cleaner  200 . The mounting pads  225  will typically be positioned on base  214  ( FIG. 6 ) of central section  205 , for convenience and modular assembly. 
   For the example shown the mounting pads  225  are directed at an angle of about 90° from a direction of removal of cover  206 , although alternatives are possible. This example, then, is consistent with a depicted orientation in which the cover  206  is removed laterally from the air cleaner housing  201 , as opposed to being lifted directly upwardly, during servicing. Alternative orientations of mounting can be used with principles described herein, however. 
   Air cleaners that are in accord with the descriptions herein can be manufactured in a variety of sizes, for use with a variety of equipment. Typically the air cleaners will be used with mobile equipment such as trucks, and will be installed under a hood arrangement of the trucks. In  FIG. 7  some example dimensions are indicated, for an example of such application. Of course variations from these dimensions can be used for alternate applications. The example dimensions of  FIG. 7  are as follows: AA=744.3 mm; AB=336.8 mm; AC=330.1 mm. 
   In  FIG. 8  a top plan view of the air cleaner  200  is depicted. It is noted that in  FIG. 8  the outlet section  203  is consistent with the outlet section of  FIG. 7 , and 180° reversed from the outlet section as depicted in  FIG. 6 . It is also noted that in:  FIG. 8  an alternate inlet section  202 , with inlet arrangement  227  is depicted. This again demonstrates the convenience of the modular construction. It is noted that some different, example, dimensions are provided in the example of  FIG. 8 , as follows: BA=744.9 mm; BB=304.6 mm; BC=491.4 mm. 
   In  FIG. 9  air cleaner  200  is depicted with: access cover  206  removed; and, without any installed filter cartridges. Thus interior  201   i  of housing  201  is viewable. 
   As will be understood from discussion with respect to the following figures, the air cleaner housing  201  is configured specifically to accept more than one size of primary filter cartridge, securely, as alternatives. That is, for example, the air cleaner housing  201  can be used with a first primary filter cartridge of a first axial length, or can alternatively be used with a second primary filter cartridge of a second, different, axial length. Examples of this are discussed below in connection with other figures. Configurations that allow for this, provide for a wide variety of options in the use of the air cleaner  200 . In particular the same air cleaner  200  can be used with a variety of different specific vehicles, depending on the vehicle engine size and air cleaner demands, by modifying the installed filter cartridge without modifying the air cleaner housing itself. Also the same vehicle can be provided with different primary filter cartridge configurations, depending on the environment of use (for example: city; over-the-highway; and, off-road). 
   Herein the term “axial length” when used in connection with a primary filter cartridge, is meant to refer to a direction of extension generally between, or generally parallel with, a direction between inlet and outlet flow faces. A total overall axial filter cartridge, of course, would be measured including axial projection of any structures positioned on the media pack projecting axially outwardly therefrom. The total axial length of the media pack, would typically only refer to a maximum distance between the inlet flow face and the opposite outlet flow face. 
   Referring to  FIG. 9 , although alternatives are possible, the particular air cleaner  200  depicted, is configured for utilization with various alternative primary filter cartridges that each have a housing seal member that seals in place using an outwardly directed radial seal. This type of seal is discussed in greater detail below. Referring to  FIG. 9 , secure, sealing, engagement of a filter cartridge in the housing  201  is necessary to proper primary filter cartridge operation, to ensure that unfiltered air does not bypass the primary filter cartridge in moving from the inlet  210  to the outlet  211 . The air cleaner housing  201  of  FIG. 9 , is provided with a housing seal surface for engagement by the filter cartridge at  230 . That is, ring or track  230  comprises a continuous housing seal surface for a primary filter cartridge carrying a radial housing seal thereon, as described below. 
   In the previous paragraph reference was made to the housing seal member sealing in place using an “outwardly directed radial seal.” The term “radial” in this context, is generally meant to refer to a direction generally perpendicular to an axial direction of extension of a media pack or filter cartridge. The term “outwardly” in this context, is meant to refer to a direction radially outwardly from a center axis of the media pack. These terms are discussed further below, in connection with drawings that show the primary filter cartridges. 
   It is noted that interior  214   i  of base  214  is configured with multiple (in this instance two) biasing tracks therein, to accommodate two different sized elements. A first biasing track is indicated generally at  236  and a second at  237 . Operation and use of these biasing tracks will be understood from further discussion below. In general, however, it should be noted that the first biasing track  236  is positioned a different distance from inlet section  202  and outlet section  203 , that is the second biasing track  237 . That is, the two biasing tracks  236 ,  237  are spaced, axially, within the air cleaner housing  201 , with biasing track  237  closer to the outlet section  203 , and biasing track  236  positioned closer to the inlet section  202 . Typically air cleaner housings according to the present disclosure will include at least two primary filter cartridge biasing tracks, although more than two are possible. Herein first and second biasing tracks will be discussed, and features thereof, without regard to whether they are the only two biasing tracks on only the first and second of more than two biasing tracks. 
   Still referring to  FIG. 9 , it is noted that the air cleaner housing  201  depicted, is generally configured for receipt of filter cartridges having exterior seal perimeter (peripheral) shapes that are generally oval (two narrowly curved ends with opposite sides) and media packs that have an exterior perimeter (peripheral) shape that is generally oval (again two narrowly curved ends with opposite sides). A typical oval arrangement would be a perimeter shape referred to herein as racetrack, in which the perimeter definition of both the seal and the media pack is to have opposite curved ends with opposite, generally parallel, sides extending therebetween. This is shown and discussed below, with example primary filter cartridges. Of course the principles described herein can be applied with alternate configurations of primary filter cartridges and/or seals, for example circular or alternate oval shapes in which not only are the two ends curved, but the opposite sides are also curved. 
   In  FIG. 10  a side elevational view of the air cleaner  200 ,  FIG. 9 , is viewed. Again the air cleaner housing  201  is viewed with the access cover  206  removed. Referring to  FIG. 10 , one can see that the first biasing track  236  is generally u-shaped track having opposite sides  236   a ,  236   b , (adjacent opposite housing sides  201   x  and  201   y  respectively) and a rounded center  236   c , positioned between the sides  236   a ,  236   b . A similar track is discussed in PCT Publication WO 05/107924, published Nov. 17, 2005, incorporated herein by reference. 
   Biasing track  236  generally finds a unshaped slide surface  236   s  which is oriented directed axially, generally toward outlet section  203  and away from outlet section  202 . Surface  236   s , as discussed below, is generally in a plane not quite perpendicular to a direction of extension between sections  202 ,  203 , but rather tilted slightly with respect to a plane perpendicular to a flow direction between inlet section  202  and outlet section  203  such that center  236   c  is slightly closer to outlet section  203 , than are side tips  236   t  of each of the side sections  236   a ,  236   b.    
   The second biasing track  237  is also viewable having generally u-shape with opposite sides  237   a ,  237   b , and rounded center  237   c . Again, it is noted that biasing track  237  is positioned axially closer to outlet section  203  than is by track  236 . Alternately stated, biasing track  236  is positioned closer to inlet section  202  than is biasing track  237 . 
   The second biasing track  237  generally defines a track surface  237   s  oriented directed axially toward outlet section  203  and away from outlet section  202 . Surface  237   s  typically is planar, and is typically oriented in a plane not quite perpendicular to a flow direction between sections  202  and  203 , but rather slanted slightly therefrom, typically at a different declination angle than surface  236   s , as discussed below. For surface  237   s , tips  237   t , then, are generally oriented closer to section  202 , than is the surface  237   s  in center  237   c.    
   Typically, the biasing tracks  236 ,  237  are configured with selected, different, dimensions. For the example shown, one dimensional difference is the width between the opposite sides of the u-shape. In particular for first biasing track  236 , sides  236   a  and  236   b  (and tips  236   t ) are spaced closer together, than the sides  237   a ,  237   b  (and tips  237   t ) for the second biasing track  237 . Such a difference in dimension can be utilized to advantage, as discussed further below. 
   Herein, in some instances a comparison will be made between the direct distance between tips  236   t  and the direct distance between tips  237   t , with a comparison being that the distance between tips  237   t  is greater than the distance between  236   t . When the term “direct distance” is used in connection with this comparison, the intent is to refer to the shortest distance between the tips characterized, not the distance that follows the u-shape of the corresponding biasing track. 
   Referring to  FIG. 10 , for the example shown the larger dimension for biasing track  237 , in width between sides  237   a ,  237   b , is accommodated by providing an outwardly directed unshaped trough or projection segment  239 , in which surface  237   s  forms one of the axial sides, i.e., a side closest to inlet section  202  and facing outlet section  203 . 
   As above noted, each of the unshaped biasing tracks  236 ,  237  generally extends inwardly of section  214  at an acute angle tapering toward outlet section  203  from inlet section  202 . Somewhat different angles can be used, to advantage, for these two tracks. Typically each of the tracks will extend at a declination angle of at least 0.5°, usually not more than 15°, typically within the range of 2° to 10°. The term “declination angle” as used in this context, is meant to refer to an acute angle between a plane defining a respective one of the tracks  236 ,  237  and a plane perpendicular to the general direction of air flow through air cleaner  200  from inlet  202  to outlet  203 . Typically when a difference in the declination angle is used for the two tracks  236 ,  237 , it is at least 0.5°. 
   Dimensions provided in  FIG. 10 , for the example shown, are as follows: CA=744.3 mm; CB=336.8 mm; and, CC=330.1 mm. 
   As indicated previously, air cleaner housing  201  is configured to allow for alternate receipt for at least two different sizes (lengths) of primary filter cartridges therein. This is facilitated by the two biasing tracks  236 ,  237 . As indicated, the air cleaner  200  could be provided with a biasing track arrangement that allows for more than two alternate possibilities for cartridge lengths using the same principles discussed. 
   Although alternatives are possible, typically the air cleaner housing  201  would be configured to alternately accept different cartridges which differ in overall axial length by at least 40 mm, typically at least 60 mm, often at least 80 mm, and usually 100-200 mm, although alternatives are possible. The distance between the locations of the biasing tracks  236 ,  237  is not necessarily the same as the difference of the lengths of the cartridges, since in one example shown the cartridge engages a biasing track at its end, whereas the second cartridge engages a biasing track at a location spaced from an end of the media pack. However, in general, a difference in axial spacing between the biasing tracks will be at least 40 mm, typically at least 60 mm, and usually at least 80 mm. Often the distance is also within the range of 100-200 mm. 
   B. An Example First Primary Filter Cartridge and Installation. 
   In  FIGS. 11 and 12 , a first primary filter cartridge  250  is depicted for installation in air cleaner  200 . Specifically, primary filter cartridge  250  is configured to be installed in a position extending between a location contacting (or if not contacting adjacent) first biasing track  236  ( FIGS. 9 and 10 ) with sealing at housing seal surface  230 . Thus, for the example shown in  FIGS. 9 and 10  the first filter cartridge  250  is sized as a maximum (axial) length (or nearby maximum length) cartridge that can be fit within interior  214   a  of housing base  214 . 
   In  FIG. 11  a top plan view of the filter cartridge  250  is depicted. The cartridge  250  is oriented as it would be during installation in the housing  201 , with the observer looking down the filter cartridge  250 . 
   Referring to  FIG. 11 , the filter cartridge  200  includes the following general features: media pack  251 ; seal arrangement  252 ; guide arrangement  253 ; and, handle arrangement  254 . 
   The media pack  251  generally comprises z-filter media in accord with the descriptions provided above. As explained above, z-filter media can be provided in any of two forms: as a coiled arrangement of a single facer comprising a fluted (corrugated) media sheet secured to a facing media sheet; or, as a stack of strips of single facer each comprising a fluted (corrugated) media sheet secured to a facing media sheet. Either type of arrangement can be provided with the general techniques described herein. However, the assemblies depicted are specifically configured for use with coiled arrangements, and variations in shape and other detail would typically be used when a stacked media pack arrangement is to be used. Thus, the example media pack  251  depicted comprises a coiled z-filter media arrangement  251   z , comprising a fluted (corrugated) media sheet secured to a facing media sheet, coiled with the facing sheet directed outwardly. 
   The media pack  251  generally includes (defines) an inlet face  255  and an outlet face  256 . The outlet face  256  is generally located at an opposite (axial) end of the media pack  250  from the inlet face  255 . 
   The media pack  251  is generally closed to flow of air therethrough, between inlet face  255  and outlet face  256 , unless the air passes through a media sheet (fluted or facing) with filtering. 
   The particular media pack  251  depicted has a generally obround perimeter (peripheral) shape, particularly an oval perimeter shape comprising two opposite curved ends  251   a ,  251   b  with sides  251   c  and  251   d  extending therebetween. The particular shape is racetrack, with sides  251   c  and  251   d  being approximately straight and parallel to one another. 
   The seal arrangement  252  is depicted mounted at an end of the media pack  251  defining outlet face  256 . However in some embodiments, alternate arrangements are possible. The seal arrangement  252  comprises housing seal member  265  oriented, positioned and sized to form a housing seal with housing seal surface  230 ,  FIG. 9 , when cartridge  250  is operably installed within an interior  201   a  of housing  201 . The particular housing seal arrangement  252  depicted is positioned and configured for housing seal member  265  to form an outwardly directed radial seal, compressed upon engagement with region  230 . A variety of types of housing seal arrangements  252  are possible, selected ones of which are described in U.S. Pat. Nos. 6,783,565, 6,190,432, 6,350,291, 6,610,117, U.S. Publication US 2005/0166561, published Aug. 4, 2005, PCT Publication WO 05/63361 and U.S. Provisional Application 60/735,650, filed Nov. 9, 2005, incorporated herein by reference. Some examples of such seal arrangements are discussed briefly below. Typically, the housing seal region  265  comprises a compressible polymeric material, for example foamed polyurethane positioned around rigid structural member, against which the polymeric material in region  265  can compress, when inserted into region  230 ,  FIG. 9 . 
   Typically, the seal region  265  is positioned at a location axially beyond end face  256  of the media pack  251 , in a direction opposite face  255 . That is, the seal region  265 , which sealingly engages housing section  230 , does not extend around the media pack  251 , but rather is mounted on a frame structure or extension projecting axially outwardly from the media pack  251 , away from the media pack  251  in a direction opposite surface  255 . For the example shown, the seal region  265  is part of an overmold  266  which has a second, but integral, portion  267  that does engage and surround the media pack  251 . 
   The principles described herein can be utilized with alternate seal arrangements, including ones that extend around a media pack. However for the particular housing  201  depicted, and primary filter cartridges  250  described herein, a seal arrangement  252  described, in which the housing seal member  265  includes a radially outwardly directed seal region positioned at a location axially outwardly from the media pack  251 , is typical. 
   Still referring to  FIG. 11 , for the example shown, filter cartridge  250  includes, mounted on (and in the example shown surrounding) the media pack  251  at a region adjacent end face  255 , a preform support  270 . The term “preform” as used herein in this and related contexts, refers to a structural member formed and then later attached to the media pack  251 , during assembly of the cartridge  250 . The preform support  270  includes, among other things, guide arrangement  253  and handle arrangement  254 . In addition, the particular preform support  270  depicted, includes an inlet end grid  271  which extends across face  255 . 
   Typically, the preform support  270  would be molded from an appropriately robust plastic material with the features of the inlet grid  271 , guide arrangement  253  and handle arrangement  254 , molded integrally as part thereof. 
   For the example shown, the guide arrangement  253  comprises an edge  253   a  of the preform support  270  adjacent (typically slightly axially outwardly from) end face  255 . Some or all of the edge  253  (guide arrangement  253 ) engages some or all of surface  236   s  of the first biasing track  236 , slidably, during installation of the cartridge  250  into housing interior  201   a . More specifically, during installation of cartridge  251 , edge  253   a  of the guide arrangement  253  is positioned in axial overlap in contact with surface  236   s , to slide therealong during installation. 
   Referring now to  FIG. 12 , preform support  270  includes handle member  254  thereon, positioned on a platform region  275  of support  270 . The example handle member  254  depicted, is positioned in overlap with one of the curved ends  251   b  of the media pack  251 . 
   Handle member  254  is sized and shaped to be easily grasped by an installer and service provider. It is also sized with a perimeter (in this instance generally rectangular with finger scallops) to engage a feature in the access cover  206 ,  FIG. 6 , discussed below. The particular perimeter definition of handle member  254  for the example shown,  FIG. 12 , includes finger scallops or depressions  254   a  on opposite sides of handle member  254 , directed toward faces  255 ,  256  respectively. For the example shown, a service provider&#39;s fingers can be positioned under surface regions  254   b  under each of the opposite sides  254   c , facing surface  256 , and  254   d , facing surface  255 . Alternate arrangements are possible. 
   During installation, the handle member  254  is typically grasped, and the cartridge  250  is inserted into base interior  214   i  with: end  277 ,  FIG. 11 , of the seal region  265 , and end  251   a  of the media pack  251  first inserted; and, with the guide arrangement  253  slidably positioned against (and in engagement with) surface  236   s  of the first biasing track  236 ,  FIG. 10 . With continued insertion, the cartridge  250  will slide along surface  236   s  of the biasing track  236 , pushing the seal region  265  further into engagement with housing seal surface  230 . Initial engagement will involve end  277  overlapping housing seal surface  230 . Final securement of the housing seal occurs by the service provider tipping the cartridge  250  in the direction of arrow  280 ,  FIGS. 13 and 14 , to position the cartridge  230  in sealing orientation. This will ensure that the housing seal region  265  is fully engaged with the housing seal surface  230 , in a radial sealing manner. In  FIG. 14 , a view analogous to  FIG. 13  is shown, from a top view, and with the inlet section  202  of the housing modified from the inlet section  202  of  FIG. 13 . 
   It is noted that in  FIGS. 13 and 14 , the cartridge  250  is already maximally tipped in the direction of arrows  280 , into full sealing. 
   Referring to  FIGS. 9-14 , it will be understood that engagement between the preform support  270  (in particular edge  253   a  of guide arrangement  253 ) and the biasing track  236  occurs as a sliding engagement with guide arrangement  253  contacting axial slide surface  236   s  of track  236 . The term “axial” in this context, is meant to refer to the fact that surface  236   s  which faces axially toward outlet section  203  from inlet section  202 . Once the final seal engagement occurs,  FIG. 13 , guide arrangement  253  will be tipped out of axial or sliding contact with all or a portion of surface  236   s . Whether or not contact is retained (after tipping into sealing engagement) between guide arrangement  253  and a portion of center  236   c ,  FIG. 9 , is dictated by the various dimensions of the components involved. However, the tipping described, will typically move the guide arrangement  253  out of direct contact with sides  237   a ,  237   b.    
   In  FIG. 15 , a side elevational view showing primary filter cartridge  250  installed in housing  201  is also shown. It can be seen that the cartridge  250  substantially fills the space between the first biasing track  236  and the housing seal surface  230 . However, it is noted, again, that the cartridge  250  is tipped slightly away from complete (and in some possible instances all) contact with the first biasing track  236 . 
   Still referring to  FIG. 15 , it is noted that the second biasing track  237  is not engaged by the cartridge  250 . Rather the biasing track  237  is depicted unused, within projection  239 , surrounding cartridge  250 . As a result, it is observed that media pack  251  extends across biasing track  237 , without engaging the biasing track  237 ; and the filter cartridge  250  does not engage slide surface  237   s  of biasing track  237 . 
   When the access cover, discussed below in connection with  FIG. 16 , is installed, provision is made to prevent the cartridge  250  from tipping in the direction of arrow  281 ,  FIG. 15 , out of the sealed arrangement shown in  FIGS. 13-15 . 
   Example dimensions provided in  FIGS. 11-15  are as follows: DA=286.6 mm; DB=9.4 mm; DC=447.7 mm; EA=256.7 mm; EB=271.2 mm; FA=744.9 mm; FB=304.6 mm; FC=491.4 mm; GA=744.3 mm; GB=336.8 mm; and, GC=330.1 mm. 
     FIG. 15A  is an enlarged fragmentary view of a portion of  FIG. 15 , showing a portion of the cartridge  250  positioned relative to the first biasing track  236 , after installation. In  FIG. 15A , example dimensions provided are as follows: HA=5.5 mm; HB=12.0 mm. 
   Referring to  FIG. 12 , the preform  270  includes opposite spacers or spacer projections  283 ,  284  centrally positioned along opposite sides  251   d ,  251   c , respectively of the primary filter cartridge  250 . Referring to  FIG. 11 , in which spacer projection  283  is depicted, each spacer projection  283 ,  284  typically extends generally parallel to inlet face  255  and projects radially outwardly from an adjacent portion of preform  270 . The term “projects radially outwardly” in this context, refers to a projection away from the media pack  251  and preform  270 , in a direction radially outwardly from a center of the media pack  250 , as opposed to directed axially as discussed above. A typical amount of radial outward projection is at least 2 mm, typically 3 to 15 mm, inclusive, usually 4-12 mm inclusive, relative to adjacent portions of preform support  270  although alternatives are possible. Referring to  FIGS. 15 and 15   a , the spacers  283 ,  284  facilitate stable positioning of the cartridge  250  within the housing interior  201   a  by filling space between preform  270  and an interior wall region  285 , of housing interior  201   i . This will facilitate installation and stable positioning of the cartridge  250  once installed. 
   Referring to  FIG. 11 , each spacer  283 ,  284  typically extends along a respective side ( 251   c ,  251   d ) of side  251 , a distance of at least 40 mm, usually at least 60 mm, typically not more than 150 mm and often within the range of 60 mm to 100 mm. In more general terms, for an oval media pack  251  as depicted, the spacer projections  283 ,  284  typically extend a distance corresponding to at least 5%, and typically within the range of 5% to 40% of the maximum width of the media pack  251  between outer surfaces curved ends  251   a ,  251   b . Herein, a distance of extension of the side spacer projections  283 ,  284  between opposite ends, will sometimes be referred to as the “length of extension.” Typically, each one of the spacer projections  283 ,  284  is continuous along its length of extension. However, in some instances gaps can be provided. 
   In  FIG. 15A , dimension between opposite axial sides  284   a ,  284   b  of the projection  284 , will be referred to as the axial thickness of the projection  284 . Typically each of the spacer projections  283 ,  284  has an axial thickness of at least 6 mm, and usually within the range of 6 mm-15 mm, inclusive, although alternatives are possible. 
   It is noted that the spacers  284 ,  285  are spaced from end face  255  of the media pack. This will be typical for arrangements as described herein. The amount of this spacing can be varied, depending on the particular housing arrangement, but typically will be at least 10 mm, usually at least 15 mm. For the particular example shown in  FIGS. 15 and 15A , projections  283 ,  284  are spaced from end face  255  by a distance of at least 18 mm (typically 15-25 mm), although alternatives are possible. 
   Attention is now directed to  FIG. 16  in which a cross-sectional view is taken of the assembly  200 , generally along line  16 - 16 ,  FIG. 15 . It is noted that for the orientation of  FIG. 16 , the view is looking up into the upper half of the assembly  200  of  FIG. 15 , but the assembly has been inverted for the typical viewer to be looking down onto the picture. 
   In  FIG. 16  the housing  201  is shown with an inlet section  202  corresponding generally to that shown in  FIG. 14 , but it could be modified in accord with the discussions herein. Further in  FIG. 16  the housing  200  is depicted with an outlet section  203  generally in accord with  FIG. 14 , but it could be modified in accord with the descriptions herein. 
   Cartridge  250  is shown positioned within housing interior  201   a , in particular in section  205 . Access cover  206  is depicted positioned in place as part of housing section  205 . 
   Selected features of the access cover  206  relating to the installation of cartridge  250  are as follows: (a) the access cover  206  includes interiorly directed projection  290  thereon positioned to extend axially behind a portion of end  255  of the media pack  251 , and also behind an axial end of preform  270 . The term “behind” in this context, is meant to refer to a projection or extension to a location between the cartridge features indicated (end  255  and preform support  270 ) and outlet section  202 . Projection  290  will prevent the cartridge  250  from tipping or backing out of sealing contact with housing seal surface  230 , in the direction of arrow  281 , until access cover  206  is removed. Referring to  FIG. 16 , end face  256 , in this instance an outlet face of media pack  250  is viewable, as well as outlet end preform  295  including rigid seal support  296  positioned radially supporting housing seal arrangement  265 . In addition outlet end preform  295  is shown with a grid  297  extending across face  256 . 
   Another feature in access cover  206  is receiver  300  sized and positioned to receive therein handle arrangement  254 , as a projection, in a mating manner, when service cover  206  is installed. The receiver  300  will help stabilize the cartridge  250  is proper position, and will help ensure that a proper cartridge  250  has been installed, for the air cleaner configuration desired. 
   Many of the housing of the filter cartridge features just described, are also characterized in PCT Publication WO 05/107924, published Nov. 17, 2005, incorporated herein by reference. 
   Still referring to  FIG. 16 , it is noted that opposite access cover  206 , housing base  214  includes a receiver section  305 , with a greatest depth, relative to the cartridge  250 , provided adjacent face  255  as shown at  305   a . The receiver section  305  facilitates dismounting the cartridge  200  as follows. The access cover  206  is removed, after disengaging the latches  216 ,  FIG. 6 . Then, by manipulating the cartridge  250 , for example by pressing on handle arrangement  254 , the handle  254  will tip in the direction of arrow  281  and a portion  306  of the cartridge  250  will push into receiver  305 . This movement pulls edge (region)  278  of the seal arrangement  265  out of sealing contact with region  230 . The cartridge  250  is now loosened, and it can be removed for example by grasping and pulling the handle  254 . This type of arrangement for mounting and dismounting a filter cartridge is generally described in PCT Publication WO 05/46841, published May 26, 2005, incorporated herein by reference. 
   Still referring to  FIG. 16 , it is noted that for the air cleaner assembly  201  depicted, the housing seal surface  230  is positioned within the same modular component that forms outlet section  203 . Variations from this are possible, however. 
   It is noted that the air cleaner  200  can be configured (typically by modification of outlet section  203 ), for receipt therein, and mounting therein, of a secondary or safety filter if desired. Such arrangements as those described in PCT Publication WO 05/107924, published Nov. 17, 2005, incorporated herein by reference, could be adapted for systems in accord with the principles described herein. 
   In  FIG. 17 , a cross-sectional view analogous to  FIG. 16  is depicted except showing the air cleaner housing  201  without cartridge  250  installed, but with access cover  206  in place. 
   C. Installation of a Second, Shorter, Filter Cartridge within the Air Cleaner Housing  201  as an Alternative,  FIGS. 18-24 . 
   As discussed previously, the air cleaner assembly  200  is specifically configured as to be capable of alternately receiving, securely, as least two different sized filter cartridges therein, depending on the needs of the vehicle or vehicle operator. By “alternately receiving” in this and related context, it is meant that the air cleaner housing  201  can be configured to receive a first sized primary filter cartridge or second sized primary filter cartridge, but not the two at the same time. Description of features and installation of a second, shorter, filter cartridge is described in connection with  FIGS. 18-24 . 
   Turning first to  FIGS. 18 and 19 , a second filter cartridge  350  is depicted also sized and configured to be mounted with an air cleaner  200 , analogously to cartridge  250 , but having a smaller length dimension between flow faces and thus occupying less space of interior  201   a . Referring to  FIG. 18 , the second filter cartridge  350  comprises a media pack  351  seal arrangement  352 , guide arrangement  353  and handle arrangement  354 . The media pack  351  includes an inlet face  355  and an opposite outlet face  356 . The media pack  351  may be generally as previously described for media pack  251 , except configured and sized for the particular example shown. The particular media pack  351  shown, comprises a coiled media pack fluted (corrugated) media sheet secured to a facing media sheet with the facing media sheet directed to the outside. The coiling is in an oval shape, having opposite curved ends  351   a ,  351   b  with opposite sides  351   c  and  351   d  extending therebetween. The particular example shown is racetrack, with opposite sides  351   c  and  351  being generally straight, in extension between the curved ends  351   a ,  351   b . In  FIGS. 18-19 , the dimensions indicated, as an example, are as follows: IA 473.0 mm; IB=163.6 mm; JA=23.1 mm; JB=257.0 mm; JC=23.1 mm. 
   Although alternatives are possible, typically a length between opposite flow faces for a smaller cartridge, installed within arrangements according to the present invention, by comparison to the larger cartridge, will be such the smaller cartridge is at least 40 mm shorter in length, typically at least 60 mm shorter, often at least 80 mm shorter in length, and in many instances at least 100 mm shorter in length, for example 100 mm-200 mm shorter, inclusive. Alternatives from this, of course, are possible. 
   The seal arrangement  352  may be generally as described previously for seal arrangement  252 , in some instances can be identical. Thus, the depicted housing seal arrangement  252  comprises housing seal member  365  and an integral portion  366 ; the integral portion  366  surrounding media pack  351  and the seal member  365  being positioned on a support projecting axially outwardly away from the media pack face  356 , in a direction opposite face  355 . The housing seal member  365  defines an outer periphery for the example shown that is of a same general shape as the outer periphery of the media pack  351 , in this instance oval with two opposite curved ends and two opposite sides, the example shown being racetrack with the opposite sides being straight and parallel to one another. Further, media pack  350  comprises a preform support  370  positioned thereon including an end grid  371  extending across face  355 . The preform support  370  includes many features analogous to preform support  270 , but is sized and shaped differently for convenience. In particular handle arrangement  354 , positioned on preform support  370 , is of a smaller size (and different shape) than handle arrangement  254 , for convenience. 
   In  FIG. 19 , a plan view of the filter cartridge  350  is depicted; the view point is looking toward the handle arrangement  354  as it would be oriented for installation in the housing  201 , when the housing  201  is positioned generally as shown in  FIG. 6 . The preform support  370  includes opposite sides  374 ,  373 , with spacers  383 ,  384  respectively projecting radially outwardly therefrom. The distance between sides  373 ,  374 , is preferably greater than interior dimension of the housing  201  between regions  201   x ,  201   y ,  FIG. 10 , inhibiting the cartridge  350  from being installed using first biasing track  236 . Typically and preferably the distance between the sides  373 ,  374  is sufficiently large that the cartridge  350  can only be installed if the sides  373 ,  374  are positioned in the trough shaped projection  239 ,  FIG. 10 . The sides  373 ,  374  depicted generally comprises opposite, radially outwardly directed, slide projections each of which has an axial face  374   a ,  373   a  facing generally in the direction of the inlet face  355 . These are positioned to engage the slide surface  237   s  of biasing track  237 , during installation. The slide surfaces  373   a ,  374   a , which are positioned to engage slide surface  273   s  of the biasing track, are typically at least 5 mm, and usually at least 10 mm wide, in projection outwardly from an adjacent portion of preform support  370 , not including the amount of projection of the side projections  383 ,  384 . The radial slide projection comprising projections  373 ,  374  is typically positioned spaced from inlet face  355  toward outlet face  356  by a distance of at least 10 mm, typically 10-40 mm, often at least 15 mm, for example 15-30 mm, inclusive, although alternatives are possible. 
   Proper installation of the filter cartridge  350  will be understood by reference to  FIGS. 20-24 . 
   Referring first to  FIG. 20 , the cartridge  350  is shown installed within housing  201 , without access cover  206  in place. That is, the cartridge  350  is positioned with seal member  352  in sealing engagement with housing seal track  230 . The cartridge  350  is installed by first engaging some or all of guide arrangement  353  with some or all of biasing track  237 , and sliding the cartridge  350  against the track surface  237  during installation. Once sliding is completed, the cartridge  350  would then be rocked or tipped in the direction of arrow  390 , to complete the sealing. (In  FIG. 20 , the cartridge  350  shown tipped as far in the direction of arrow  390  as it will go, during installation.) Thus, installation is analogous to cartridge  250 , but using a biasing track  237 . In  FIG. 20 , the cartridge  350  is shown installed after the tipping in the direction of arrow  390  has occurred. 
   Referring still to  FIG. 20 , it is noted that housing  201  includes a unshaped trough  392  (in both cover  206  and base  214 ) positioned as an inside of projection  239  and positioned to receive edge  370   e  of preform  370  therein, during installation. One axial inside surface (the side  237  closest to inlet section  202  and facing outlet section  203 ) of the receiver  392  comprises biasing surface  237 . The groove or trough  392  preferably has a greater direct dimension in width between tips  237   t  than the dimension directly between tips  236   t  of track  236 . The cartridge  350  cannot be inadvertently installed utilizing track  236 , since the distance between side projections  373 ,  374  is too great. 
   It is noted that groove or trough  392  is sized, to accommodate the tipping motion of the cartridge  350 . That is, the groove or trough  392  has a general v-shape, so that side-projection  373 ,  374  with projections  384 ,  383 , respectively thereon, can tip forwardly than the groove  392 . 
   Of course dismounting of cartridge  350  would generally involve a reverse process, with an overall operation analogous to that described for cartridge  250  above. 
   In  FIG. 21  a top plan view of air cleaner  200  with cartridge  350  sealingly installed therein is shown, without access cover  206  in place. It is noted that inlet section  202  for the arrangement of  FIG. 21  is depicted modified from inlet section  202 ,  FIG. 20 , but analogous principles are involved. In  FIG. 21 , the indicated dimensions are as follows: KA=744.9 mm; KB=304.6 mm; KC=491.4 mm. 
   In  FIG. 22 , air cleaner  200  is depicted following positioning cartridge  350  ( FIG. 21 ) with access cover  206  in place. The access cover  206  is secured in place by latches  216 . The access cover  206  includes a receiver  398  positioned to receive handle member  354 ,  FIG. 21 , therein. The receiver  398  will be configured to prevent handle  354  for moving rearward, in the general direction of arrow  399 ,  FIG. 21 , which movement would dislodge the cartridge  350  from a proper sealing orientation. Thus, with an arrangement as depicted, the access cover  216  is configured to prevent the shorter cartridge  350  from backing out of secure engagement once installed. The access cover  206  further includes a groove shaped receiver  398   a , as part of groove  392 , to receive a portion of projections  374 ,  373  therein, when cover  206  is in place, again stabilizing the position of the cartridge  350 . 
   In  FIG. 22 , the indicated, example, dimensions are as follows: LA=744.3 mm; LB=336.8 mm; and, LC=330.1 mm. 
   In  FIG. 23 , an enlarged fragmentary view of a portion of the assembly as depicted in  FIG. 20  is shown. In  FIG. 23 , spacer  384  can be viewed helping to center and support the cartridge  350  in position, within receiver  392 . Spacers  384 ,  383  can be shaped and be dimensionally analogous, to spacers  280 ,  281  discussed above, except modified to accommodate groove projection  392 . 
   In  FIG. 23  the indicated dimensions are as follows: MA=7.8 mm; MB=10.5 mm. 
     FIG. 24 , a cross-sectional view analogous to  FIG. 16  is shown of the air cleaner  200 , but depicting the smaller or shorter cartridge  350  in place. Housing seal arrangement  352  can be viewed as secured against housing seal track  230  by compressing the seal member  365  against support  400 , support  400  projecting axially outwardly from face  356  in a direction opposite face  355 . Grid work  401  extending across face  356  can be used to stabilize the media pack  351 . 
   Referring again to  FIG. 20 , it is noted that the example handle arrangement  354  shown has designation different from handle arrangement  254 ,  FIG. 12 . Although alternatives are possible, the particular handle arrangement  354  depicted is configured to have one edge  354   a , which faces toward outlet section  203 , that is scallop-shaped for receiving fingertips. Further the edge  354   a  is positioned so that fingers can be pushed underneath it, to facilitate manipulation of cartridge  350 . An edge  354   b , opposite edge  354   a , for the example shown, is closed, meaning it has no undercuts or similar structure, in a typical preferred arrangement. Alternatives are possible. 
   It is noted that the size of top  354   c  of handle arrangement  354  is generally smaller than a perimeter size of top  254   c , of handle arrangement  254 ,  FIG. 12 . Variations from these definitions are possible, but the examples shown are typical. 
   D. Selected Structural Variations, System of Use and Example Seal Variations, FIGS.  25 - 32 . 
   (a) Seal Variations,  FIGS. 28-31 . 
   In  FIGS. 28-31 , some structure variations for the seal arrangements are discussed and shown. In  FIG. 28  an example media pack  451  is depicted, which can correspond to either media pack  251  or media pack  351 . A housing seal arrangement  452  is depicted comprising a seal member  453  with an integral portion  454 . Support  455  for backing up the seal during compression is shown. The support  455  is secured to the media pack  451  by the overmold  454 . Grid  457  is shown extending across media pack (downstream) flow face  458 . The type of seal arrangement depicted in  FIG. 28  is generally analogous to the ones depicted in previously discussed figures, and is discussed in detail in U.S. patent application Ser. No. 11/019,883 filed Dec. 21, 2004; and PCT Publication WO 05/63361, published Jul. 14, 2005, incorporated herein by reference. 
   In  FIG. 29 , an alternate arrangement is shown. Here seal member  480  is molded onto a support  481 . The support  481  would be secured to the media-pack by an adhesive or other material, but not by a structure integral with the seal arrangement  480 . Thus for typical operation, the seal member  480  would be premolded onto the support  481 , and then the combination would be secured to the media pack. Such seal arrangements are described for example in U.S. Pat. Nos. 6,783,565, 6,190,432, 6,350,291, 6,610,117, incorporated herein by reference. These principles can be applied with media packs installed in air cleaners according to the present disclosure. 
   In  FIG. 30 , a fragmentary view of a seal arrangement  490  including a single step or champfer section  491  is depicted. This configuration can be used as an alternate shape for the seal region for either the arrangements of  FIG. 28  or  FIG. 29 . Such arrangements are described for example in U.S. Provisional Application 60/735,650, filed Nov. 9, 2005, incorporated herein by reference. 
   Finally in  FIG. 31 , a housing seal arrangement  500  is depicted which utilizes a support  501  having a projecting lip  502  to manage sealing rise, during a molding operation. In  FIG. 31 , the media pack is shown at  504 . Such an approach, which is a modification of the approach described in  FIG. 28 , is discussed in detail in U.S. Provisional Application 60/735,650, filed Nov. 9, 2005, incorporated herein by reference. 
   An example polymeric material useable for housing the seal regions (and overmold is present) as described herein is polyurethane. An example useable polyurethane is a foamed polyurethane which will increase in volume during use. Preferred ones increase by at least 40% in volume, to fill the mold cavities (typically at least 80% in volume) and having an as-molded density of no greater than 30 lbs/cu.ft (0.48 g/cc), typically no greater than 22 lbs/cu.ft. (0.35 g/cc) and usually with in the range of 10 lbs/cu.ft (0.16 g/cc) to 22 lbs/cu.ft (0.35 g/cc); and, a hardness (Shore A) typically of not greater than 30, preferably not greater than 25 and typically within the range of 10 to 22. Of course polyurethanes outside of this range can be used, but the characterized ones are advantageous for manufacturing and handling. 
   (b) Housing Variations and Use,  FIGS. 25-27  and  32 . 
   In  FIGS. 25 and 26 , variations in air cleaners are possible by the modular constructions are depicted. Referring first to  FIG. 25 , air cleaner  200  is depicted with inlet section  202 , outlet section  203 , center section  205  with base  214  and access cover  206 . The inlet section  202  is provided with an inlet arrangement  210  which in this instance is a side inlet  210 . In  FIG. 26 , an analogous structure is shown, with the side inlet  210  of inlet section  202 ) directed in an opposite direction. Modular construction allows for fitting the parts together in these alternate constructions. 
   In  FIG. 27 , a fragmentary, schematic depiction of an air cleaner  200  positioned under the hood  600  of a vehicle  601  is provided. The air cleaner  200  is positioned above the engine block  605 . The particular air cleaner  200  depicted, includes bellows member  610  around inlet  611 , positioned to engage structure  620  on the hood  600 , during operation, when hood  600  is lowered. Of course as discussed above, alternatives are possible. From a review of  FIG. 27 , it will be apparent that the profile for the air cleaner  200  depicted in the various figures, is convenient for positioning above an engine block  605  and below a hood  600  of a vehicle such as a truck. 
   Referring to  FIG. 32 , air cleaner  200  is shown with housing  201  having cartridge  250  positioned therein, and an access cover removed. The air cleaner includes inlet section  202  and outlet section  203 . The inlet section  202  is defined with dual inlet tubes in inlet arrangement  210 , at  210   a ,  210   b . The tubes  210   a ,  210   b  can be configured to receive inlet air from two different locations, for example from separate air intake vents on opposite sides of a vehicle. 
   E. Summary of Selected Features and Feature Combinations. 
   In general terms, herein above an air cleaner assembly is disclosed including a housing defining an interior and having: an air flow inlet section; air flow outlet section; primary filter cartridge receiving section between the air flow outlet section and the air flow inlet section; and, an access cover removably positioned on the primary filter cartridge receiving section. In an example shown, the housing also includes a primary filter cartridge housing radial seal surface, for sealing an installed filter cartridge in use. 
   The primary filter cartridge receiving section of the housing includes at least first and second primary filter cartridge biasing tracks. In the example shown, two biasing tracks are depicted, but it is described that more biasing tracks can be used. 
   A first one of the at least two primary filter cartridge biasing tracks is spaced, axially, first distance (D 10 ) from the housing seal surface. A second one of the at least two primary filter cartridge biasing tracks is spaced axially a second distance (D 20 ) from the housing radial seal surface. The first distance (D 10 ) is greater than the second distance (D 20 ). More generally phrased, the first primary filter cartridge biasing track is spaced from a region in which a cartridge arrangement seals to the housing (radially or otherwise) a first distance (D 10 ) and the second primary filter cartridge biasing track is spaced from the same region a second distance (D 20 ), with the distance (D 10 ) being greater than the distance (D 20 ). Thus the arrangement is configured to bias at least two different size cartridges into position with the same seal arrangement. 
   In general, the assembly includes a first removable and replaceable filter cartridge positioned within the housing. The filter cartridge comprises a media pack having opposite inlet flow and outlet flow faces. The media pack is typically a z-filter media pack comprising a plurality of inlet flutes and outlet flutes extending between the inlet flow face and the outlet flow face. The inlet flutes are open adjacent the inlet flow face and closed adjacent the outlet flow face; and, the outlet flutes are closed adjacent the inlet flow face and open adjacent the outlet flow face, in a typical z-pack arrangement. The media pack is closed to passage of unfiltered air therethrough, between the inlet and outlet flow faces, so that air entering the inlet flow face must pass through the media in order to exit adjacent the outlet flow face. The primary filter cartridge includes a housing seal member thereon. For a typical arrangement described herein, the housing seal member is positioned in radial seal engagement with the primary filter cartridge housing radial seal surface. 
   In at least one assembly, with a larger or longer filter cartridge, the filter pack would have an axial length extending from a location adjacent the housing radial seal surface to allocation adjacent the first primary cartridge biasing track. By “adjacent” in this context, it is not meant that there is necessarily contact between the two described features. 
   In a second arrangement, the media pack would have an axial length extending from a location adjacent the first housing radial seal surface to a location substantially shorter than the first primary filter cartridge biasing track. In this instance, the cartridge would typically be installed using the second primary filter cartridge biasing track. Typically when installed with the second primary filter cartridge biasing track, the cartridge has an axial length of at least 40 mm, typically at least 60 mm, and usually at least 80 mm, and often 100-200 mm shorter than a distance between the housing radial seal surface and the first primary filter cartridge biasing track. 
   In general terms, an air cleaner assembly as disclosed, include primary filter cartridges (whether configured to use the first biasing track or the second biasing track) which include a preform support mounted on an end of the media pack opposite the housing seal member. The preform support includes a guide arrangement positioned to slidably engage a selected one of the at least two biasing track, during installation. In one example shown, the guide arrangement comprises an end edge of the preform support adjacent the inlet face. This type of arrangement, for the example shown, is used to engage the first primary filter cartridge biasing track, when that biasing track is positioned the furthest from the housing radial seal surface, of any of the biasing tracks. 
   In selected examples shown herein, the guide arrangement comprises a side projection or flange arrangement projecting radially outwardly from sides of the preform support location spaced at least 5 mm, typically at least 10 mm, usually at least 15 mm, for example 15-30 mm, from the inlet face toward the outlet face. Such a guide arrangement is not configured for engagement with a typical first biasing track as described herein, but rather is positioned for engagement with a second biasing track that accommodates a shorter filter cartridge than the first biasing track. 
   In typical arrangements, the air cleaner assembly is configured such that the access cover includes a primary filter cartridge engagement and retainment arrangement thereon. An example features of a primary filter cartridge engagement and retainment arrangement, is a projection on the cover which extends interiorly of the air cleaner, to a location behind a primary filter cartridge. Such an arrangement is shown and described in which the projection on the access cover is positioned to project to a location behind a primary filter cartridge that is installed utilizing the first biasing track, i.e., the longer possibility for a primary filter cartridge. 
   Other features of a primary filter cartridge engagement and retainment arrangement in the access cover, include spaced handle arrangement receivers in the access cover, each of which is sized and located to engage handle member on one of the possible primary filter cartridges for installation. 
   Another example feature of a primary filter cartridge engagement and retainment arrangement on the access cover, is a groove or trough, for engagement with a projection on one of the possible filter cartridges. 
   In an example shown, the first biasing track within the primary filter cartridge receiving section has a unshaped slide surface facing generally toward the air flow outlet and facing generally away from the air flow inlet section. This first unshaped slide surface includes side tips projecting toward the access cover and a center projecting away from the access cover. This first unshaped slide surface is typically planar and is positioned at plane, at an acute angle X, from a plane perpendicular to flow direction between the inlet section and the outlet section by at least 0.5°, typically 2°-10°. A typical arrangement is with the tipping such that the side tips of the first unshaped slide surface is spaced further from the outlet section than the center of the unshaped slide surface. 
   In example arrangements described herein, the biasing track also has a u-shaped slide surface with side tips projecting toward the access cover and a center projecting away from the access cover. The second unshaped slide surface in an example shown is planar is angled in an angle Y from a plane perpendicular to flow direction between the inlet section and the outlet section, by at least 0.5°, with the side tips further from the outlet section than a center of the unshaped slide surface. 
   Typically the angle X is different from the angle Y, usually the angle X is at least 0.5° larger than angle Y. The angle Y is typically within the range of 2° to 10°, inclusive. 
   Typically a direct distance between side tips of the first unshaped slide surface is smaller than a direct distance between side tips of the second unshaped slide surface. In this context the term “direct” is meant to refer to a shortest distance between the tips, as opposed to a distance that extends along the curve of the u-shape. 
   Typically a second biasing track is an interior slide surface of the unshaped outward projection or trough, in the primary cartridge receiving section of the housing. 
   Herein, various air filter cartridges are described for use in the air cleaner assembly. A typical air filter cartridge comprises a z-filter media pack as previously characterized. Typically that media pack has a perimeter shape with two opposite curved ends and two opposite sides extending therebetween, an example being oval and a specific example being racetrack as characterized herein. The principles can be utilized with other types of perimeter shapes, but the example shown utilize a shape as characterized. 
   A preform support is positioned on the media pack adjacent the inlet flow face. The preform support includes a handle arrangement thereon positioned overlapping one of the curved ends of the media pack. The preform support includes first and second opposite side spacer projections overlapping opposite sides of the media pack. Each one of the first and second side spacer projections typically has a length of extension corresponding to 5% to 40% of the maximum width of the media pack between the first and second curved ends, although alternatives are possible. By the term “maximum width” herein, it is meant to the largest distance across the media pack outside surfaces of the curved ends. 
   In typical filter cartridge of the type characterized, each one of the first and second side spacer projections has a radial outward projection of at least 2 mm, typically 3-15 mm, inclusive, relative to adjacent portions of the preform support. Also each one of the first and second side spacer projections typically has an axial thickness of at least 6 mm, and each one of the first and second side spacer projection is spaced at least 10 mm from an inlet end face of the media pack. 
   It is noted that the side spacer projections can be positioned on projections that include an axial surface for engagement with a slide track, although alternatives are possible. It is also noted that spacer projections can be continuous, however alternatives are possible. 
   In one example, the handle arrangement includes a lip projection directed axially toward the outlet face under which fingers can be placed, in a closed end (preventing fingers being placed thereunder) directed axially toward the inlet face. 
   IV. FIGS.  33 - 41 ; Additional Improvements 
   In  FIGS. 33-41 , additional improvements applicable, for example, to arrangements otherwise according to  FIGS. 6-32  are described and shown. In  FIGS. 33-36  an alternate cartridge is depicted, and in  FIGS. 37-38  alternate air cleaner housing and air cleaner housing/cartridge interaction features are shown. 
   Referring first to  FIG. 33 , reference numeral  700  generally comprises an air filter cartridge including improved features as characterized. The cartridge  700  comprises a media pack  701  having an air flow inlet face  702  and an opposite air flow outlet face  703 . The cartridge  701  may comprise a z-filter pack analogous to those described previously, for example corresponding to a fluted (typically corrugated) sheet secured to a facing sheet and coiled or otherwise formed into a media pack configuration as depicted. Media pack  701  may for example be identical to media pack  251 ,  FIG. 11   
   Adjacent outlet end  703  is mounted housing seal arrangement  707 . The housing seal arrangement  707  includes a housing sealing portion  708  and an over mold portion  709 . The housing seal arrangement  707  may be analogous to similar features on cartridge  250 ,  FIG. 11 . In general terms, the housing seal portion  708  is configured to form an outwardly directed radial seal with an annular housing seal surface of a housing, into which cartridge  700  is positioned for use. Overmold portion  709  provides structure that secures the housing seal arrangement  707  to the media pack  701 ; although alternate methods of securement are possible. In a typical arrangement, housing sealing portion  708  is provided with a rigid backup member, to facilitate sealing. 
   Mounted at inlet end  702  is frame member  710  comprising a band  711  circumscribing media pack  701  and secured thereto, for example with an adhesive. Band  701  includes end section  713  with handle member  714  mounted thereon. In this manner, frame piece  710  can be analogous to member  270 ,  FIG. 11 . 
   Frame piece  710  further includes an end portion  720  which projects axially outwardly from the media pack  701  in a direction away from end  703 , and provides an engagement member or arrangement for sliding engagement with a portion of a housing, during installation. This would be generally analogous to description for feature  253 ,  FIG. 11 . 
   Frame piece  710  further includes cross extension arrangement  725  extending there across, for structural stability. Features with analogous operation were described previously in connection with features  271 ,  FIG. 11 . A portion of arrangement  725  may also engage the housing in a slidable manner, for example, during installation. 
   In  FIG. 33 , a top plan view of cartridge  700  is provided, showing features viewable when looking down upon the cartridge or when oriented for installation when the housing is oriented analogous to  FIG. 9 . A side of  700  opposite the side  730 , not viewable, would typically have analogous features, as mirror images. 
   Still referring to  FIG. 33 , cartridge  700  includes a first member  740  of a projection/receiver arrangement  741 ,  FIG. 39 . The first member  740  of the projection/receiver arrangement  741 , is positioned on frame piece  710 , typically as an integral part thereof. A second member  742 ,  FIG. 39 , would be positioned as part of an associated housing, as discussed below. For the example shown, the first member  740  of the projection receiver arrangement  741  comprises at least one, and in the example shown two, projection members  745 . Further regarding the function operation of the projection members  745 , and in particular as part of the projection/receiver arrangement  741  is discussed below, in part in connection with  FIG. 39 . 
   Attention is now directed to  FIG. 34 , a side elevational view of cartridge  700 . The cartridge  700  includes opposite sides  730 ,  731 , and opposite curved ends  732 ,  733 . In a typical example, the oval shaped media pack  701  has a racetrack shape, with central portions of sides  730 ,  731  extending generally parallel to one another, and with curved ends  732 ,  733  being generally semicircular and opposite one another. 
   Referring to  FIG. 34 , frame member  710  is viewable with band  711  thereon. Handle member  714  on end section  713  is viewable. Although alternatives are possible, typically band  710  comprises a single integral molded plastic unit having the features characterized molded integral therewith. After formation, the band  710  would then be adhesively secured to a media pack  701  at the location indicated, i.e., over and around the inlet end  702 . 
   Referring to  FIG. 34 , it is noted that opposite sides  730 ,  731  of the cartridge  700  each include a first member  740  of a projection receiver arrangement  741  thereon. In the particular example shown, opposite sides  748 ,  749  of the frame member  710  are generally identical, being oriented as mirror images of one another. 
   In  FIG. 35 , an end elevational view of cartridge  700  is depicted. In  FIG. 35 , the view is taken toward outlet end  703  of the media pack  701 . Referring to  FIG. 35 , the general shape of media pack  701  is shown having: opposite sides  730 ,  731 , with central sections generally parallel to one another; and, opposite semicircular curved end sections  732 ,  733 , forming an oval (in this instance racetrack) shape. Extending across outlet face  733 , frame structure  755  is provided, as a grid work. The frame structure  755  can be formed integral with a support member  756  discussed below in connection with  FIG. 38 , supporting seal  708  during installation. 
   Handle member  714  is viewable in  FIG. 35 , comprising opposite finger receivers  714   a ,  714   b , underneath outer cover members  714   c  and  714   d  respectively. 
   Still referring to  FIG. 35 , for the example shown each of opposite sides  748 ,  749  of the cartridge  700  includes identical, oppositely mounted, first members  740  of a projection/receiver arrangement  741 . For the example shown, cartridge  700  includes: projection arrangement  745   a  on one side  730  of the media pack  700 ; and, projection arrangement  745   b  on opposite side  731 . 
   Attention is now directed to  FIG. 36 , an end elevational view of cartridge  700  taken toward inlet end  702 ,  FIG. 33 . Frame member  710  includes rim  720  extending over and projecting outwardly from end  702  of media pack  701 . Cross brace arrangement  725  extends across face  702 , to provide strength and rigidity to the structure. 
   Attention is directed now to  FIG. 37 , in which a portion of air cleaner housing  770  is depicted in cross-section. The air cleaner housing  770  is sized and configured to receive cartridge  700  therein, when installed. The housing  770  is viewed in cross-section, and such that an access cover, analogous to cover  206 ,  FIG. 7  is not viewable. The access cover will be discussed further in detail below. 
   Housing  770  includes inlet or inlet section  771 , outlet or outlet section  772 , and central or cartridge receiver section  773 . The inlet section  771  includes air flow inlet aperture  775  therein. In the example shown, the inlet section  771  is sized and configured to be secured to central section  773 , for example by mechanical fit with a welded joint therebetween, although a plurality of alternate arrangements are possible. Typically each of sections  771 ,  772  and  773  will be formed from a molded plastic, although alternatives are possible. Section  771  may be constructed analogous to section  202 ,  FIG. 26 , or with a variety of alternatives discussed previously. Inlet aperture  775  is oriented to be directed toward a selected side, although it is noted that alternate directions of the inlet aperture  775  are possible, as discussed previously herein for other examples. 
   For the particular housing  775  depicted, cartridge  700  is sized and configured to be positioned in sealing engagement with annular seal surface  780 . Further, cartridge  700  is sized to be installed with inlet end  702  oriented with frame piece  710  in sliding engagement, to the extent desired, with slide ramp  781 . Housing central section  773  also includes central ramp arrangement  785  analogous to ramp arrangement  237 ,  FIG. 20 , sized and positioned for installation of cartridge  350 ,  FIGS. 18 and 19 , if desired. 
   Still referring to  FIG. 37 , outlet section  772  includes outlet air flow aperture  788  therein. As discussed previously, outlet aperture  788  can be provided directed in a variety of directions, depending on the particular system for installation involved. This was discussed above in connection with other figures. Although alternatives are possible, in typical arrangements outlet section  772  will be preformed and then secured to central section  773 , for example by mechanical fit without welding. Typically section  772  will be formed from a molded plastic, although alternatives are possible. 
   Still referring to  FIG. 37 , housing  770  includes mounting pads  789  thereon, for secure engagement with a portion of equipment on which an air cleaner comprising the housing  770  is mounted, during use. In a typical example, pads  789  are sized, positioned and oriented to engage appropriate portions of an engine mount, during installation under a hood. However, a variety of alternatives are possible. 
   In some arrangements, the inlet aperture  775  can be fitted with an adapter, not shown, to facilitate engagement with an air flow inlet conduit arrangement, when housing  770  is mounted under the hood of a truck. 
   In  FIG. 38  an air cleaner  800  is schematically depicted comprising housing  770  with cartridge  700  installed. In  FIG. 38 , the view is a cross-section analogous to the view of  FIG. 37 . 
   Referring to  FIG. 38 , attention is first directed to engagement between housing seal member  708  on cartridge  700  (adjacent outlet end or face  703 ), with annular seal-surface or member  780  on housing  770 . Engagement is through an outwardly directed radial seal arrangement, analogous to that described for previous embodiments, see for example  FIG. 16 . An enlarged fragmentary view of the engagement is shown in  FIG. 41 . Referring to  FIG. 41  differences for the arrangement of  FIGS. 38 and 41 , relative to  FIG. 16 , relate to the nature and position of housing annular seal surface  780 , which comprises a flange member  780   a  projecting axially into an interior  770   i  of housing  770 , spaced from outer wall  770   o , by unshaped receiver section  770   u . Receiver section  770   u  is sized and positioned as an annulus region to receive air flow from a first annulus  770   a  around cartridge  700  therein, during use. This receipt is typically directly from the first annulus; i.e., without a requirement that the air first pass through the media pack  701 . In addition, portion  780   i  of member  780   a  extends beyond housing seal arrangement  707 . As a result of the structure shown, air flow will pass member  770   a  on opposite sides thereof (at base region  780   b , where flange  780   a  engages a remainder of housing  770 ), except where engaged with housing seal member  708  in use. This will help tend to cool member  780   a  in housing seal arrangement  707 . This air cooling effect will facilitate the thermal stability of seal member  708 , which typically comprises foamed polyurethane as previously described. This feature is particularly useful, when the air cleaner  800  is mounted under the hood of a vehicle, during use, where heat buildup can be substantial. 
   Thus, an improvement over the arrangements of  FIG. 16 , is that air cleaner  800  (of which housing  770  is a component) includes an annular seal arrangement  780  comprising a projection  780   a  extending into an interior  770   i  of housing  770 , toward inlet section  771  with: an outer surface  780   o  positioned to define an annulus region to receive air flow from an annular region  770   a  of housing  770 , between the housing outer wall  770   o  and the cartridge  700 . This air flow will help cool annular seal support  780  in a region where a seal is formed with outer annular housing seal arrangement  708 . 
   Still referring to  FIG. 41 , an air flow outlet end  703  media pack  701  is shown having frame piece  810  thereon comprising cross-brace structure  755  and a seal support  811 . The seal support  811  includes projection member  812  oriented for positioning of housing seal member  708  between the support  812  and the annular seal member  780 . Support  811  supports the extension or support  812  in an appropriate orientation. Such a seal arrangement is generally described in PCT Publication WO 05/63361, published Jul. 14, 2005, incorporated herein by reference. 
   Referring to  FIG. 38 , when a relatively long cartridge  700  is positioned within housing  770 , during dust loading undesirable stress or strain at region  840  of media pack  700 , where engagement and housing seal arrangement  707  occurs, can be a problem. That is: (a) under dust load, substantial weight increase in media pack  701  can occur, for example two to four times filter cartridge weight increase, from dust load; and, (b) under conditions of typical use, for example as a vehicle air cleaner, substantial vibration and shock occurs. Thus, with a relatively long media pack  701  movement adjacent end  703 , as a result of cantilevered mounting of the cartridge  700  at seal member  708 , can lead to damage or loss of media pack integrity. The problem is exacerbated, as mentioned, with a relatively long media pack  701 , i.e., typically a media pack  701  having a length, between opposite inlet and outlet surfaces  702 ,  703 , and the order of at least 230 mm or more. 
   To inhibit damage to the media pack  701 , and thus cartridge  700  integrity, with relatively long media packs  701 , a media support arrangement is typically provided in a region adjacent to (i.e. at or slightly spaced from inlet end  702 ; typically within 50 mm of, and usually within 30 mm of, inlet end  702 . A support arrangement at this location, is configured to provide engagement between the cartridge  700  and the housing  770 , so that the cartridge  702  is supported against unacceptable levels of movement at end  702 . 
   An example of such an arrangement is provided in the arrangement of  FIGS. 33-41 . In the arrangement of  FIGS. 33-41 , improvement of such a support arrangement is provided, by implementing at least one projection/receiver arrangement  741  with certain advantageous features. 
   For an understanding of this, attention is first directed to  FIG. 39 . 
   Referring to  FIG. 39 , an enlarged fragmentary cross-sectional view of air cleaner  800  is depicted, taken along line  39 - 39 ,  FIG. 38 , and with an access cover  825  in place. The fragmentary cross-sectional view of air cleaner  800  depicted in  FIG. 39  is taken through a portion of projection/receiver arrangement  741 , in particular through projection arrangement  745   b ,  FIG. 36  and directed downwardly, so that engagement with the housing  770  can be understood. 
   Referring to  FIG. 39 , then, the inlet section  771  (which is not viewable, see  FIG. 37 ), would be mounted at  820 , and the outlet section  772 , not shown, see  FIG. 37 , would be mounted at region  821 . At  825  the access cover is viewable. The access cover  825  would be generally analogous to cover  206 ,  FIG. 8 , and be removable from a remainder of housing section  773 . 
   Still referring to  FIG. 39 , double headed arrow  745   b , indicates a member of projection/receiver arrangement  741 , mounted on the cartridge  700 . In particular, double headed arrow  745   b  indicates projections or projection members  827 ,  828 . Orientation of projections  827 ,  828  is shown in  FIG. 35 . It is noted that projection members  827   a ,  828   a ,  FIG. 33 , are analogous members to projection members  827 ,  828  but on an opposite side  730  of the cartridge  700 . 
   Referring again to  FIG. 39 , double headed arrow  830  indicates a second member of the projection/receiver arrangement  741 ; arrows  830  indicating two spaced receiver members  831 ,  832  respectively. Second member  830 , in this example comprising receiver members  831 ,  832 , are positioned in housing  770 , in particular cartridge receiver section  773 , at an appropriate location for engagement with the first member  745   b  of the projection/receiver arrangement  741 . Typically housing section  773  is a molded plastic component, with second member  830  of the projection/receiver arrangement  741  molded integrally therewith. 
   Referring still to  FIG. 39 , during installation with cover  825  removed, the cartridge  700 ,  FIG. 33 , is installed, for example with some sliding engagement of end piece  710  with ramp  781 . As the cartridge  700  is then pivoted or tipped into the sealing position,  FIG. 38 , projection member  827  will pivot or tip into its final position for installation engagement with receiver  831 ; and, projection member  828  will pivot or tip into its final position for installation engagement with receiver  832 . In the example shown, member  827  also includes projection tip  837  thereon. Tip  837  is oriented to project toward access cover  825  when installed. 
   Attention is now directed to  FIG. 40 , an enlarged fragmentary view of a portion of  FIG. 39 , in particular a portion in which the part of projection/receiver arrangement  741  which comprises projection  827  and receiver  831  is depicted. Access cover  825  includes receiver pocket or indent  830  therein, including side  839 . Receiver indent  830  and side  839  are positioned as structure to engage (in this instance receive) tip  837  on side portion  831   a  of receiver  831  therein, when access cover  825  is secured in place, and to prevent the cartridge  700  from pivoting or tipping away from sealing; i.e. to prevent projection  827  from pivoting away from installation engagement with receiver  831 . Tip  837  is positioned to be engaged between portion  831   a  and side  839 . Thus, cover  825  prevents projection member  827 , and as a result the corresponding cartridge  700 , from moving (tipping or pivoting) in the direction of arrow  840  and out of installation engagement once installed. Further, receipt of projection  827  within receiver  831 , and projection  828  within receiver  832 , will inhibit movement of the cartridge  700  adjacent end  702 , beyond an acceptable amount and/or out of installation engagement. It is noted that the access cover  825  can include analogous structure positioned at an opposite side of cartridge  700 , to analogously engage an opposite or second projection/receiver arrangement. 
   Still referring to  FIG. 40 , in the example shown, receiver  831  has a pocket shape between side walls or side wall sections, which will receive projection  827  in the example shown, in a manner supporting the projection  827  on both a side  827   a  directed toward curved side end  732  of cartridge  700 ,  FIG. 33 ; and, supporting side  827   b , directed toward a curved side end  733  of cartridge  700 ,  FIG. 33 , i.e., in a direction across, but not perpendicular to, a flow direction between end faces  702 ,  703  or inlet and outlet sections,  771 ,  772 , (and not parallel (non-parallel) to flow faces  702 ,  703 ). This support will help inhibit unintended motion of cartridge  700 , with end housing  770 . Thus, the example receiver  831  has at least two, non-parallel, side wall sections, defining a receiver or pocket therebetween. 
   To facilitate the support, both the projection  827  and receiver  831 , for the example shown, provided with a generally “v” or “checkmark” shape,  FIG. 40 , with at least two diverging (non-parallel) side wall sections and, in the example shown, with a vertex present and a point of the vertex between sides directed toward an outlet portion  772  of the air cleaner  800 ; and, away from the inlet portion  771  of the air cleaner  800 ,  FIG. 38 . Referring again to  FIG. 40 , to accomplish this projection  827  is provided with sides  827   a ,  827   b  that in the example engage one another at vertex  827   c , although alternatives are possible. Also receiver  831  is provided with sides  831   a ,  831   b  diverging from one another (and in the example shown engaging at vertex  831   c ,) although alternatives are possible. 
   For the particular example shown, side  827   a  of projection  827 , and side  831   a  receiver  831 , extend in a direction nearly parallel to a direction of extension between inlet section  771  and outlet section  772 ,  FIG. 38 . Also, side  827   b  and side  831   b  extend at an angle relative to the corresponding sides  827   a ,  831   a , typically within the range of about 35° to 55°, although alternatives are possible. In  FIG. 33 , the angle between sides  827   a ,  827   b  is indicated at x; and in  FIG. 40 , the angle between sides  831   a  and  831   b  is indicated at y. Thus, sides  827   b  and  831   b  extend in a direction across a direction between inlet and outlet faces ( 702 ,  703 ) of the cartridge  700 ; in the example shown the extension being at an angle non-perpendicular to this direction. 
   At region  831   a  receiver  831  can be provided with an aperture arrangement or similar arrangement, to allow for dust passage therethrough, as projection  827  is pushed into receiver  831 , during cartridge  700  installation. 
   In more general terms, for the projection/receiver arrangement  741  depicted in  FIG. 40  a first member, (for example a projection member  827 ) is positioned on the cartridge  700 ; and a second member, (for example receiver member  831 ), is positioned on the housing  770 . The two are oriented such that during a pivoting of the cartridge  700  into sealing or installation position, the projection member  827  engages the receiver member  831  for secure holding of the cartridge  700  in position, when the cover  825  is installed. This is accomplished by defining a projection/receiver arrangement in which the first member, i.e., projection member  827 , is supported by the second member, i.e., receiver member  831 . This is provided in the example of  FIG. 40 , by utilizing a first v-shaped projection  827  and a second v-shaped receiver  828 , the second sized to receive the first in a supporting fashion. 
   For the particular example shown, projection  827  and receiver  828  are oriented with open ends  827   e ,  828   e  (i.e. ends of, or direction of, divergence for the sidewalls) directed toward the inlet end face  702  of the cartridge  700  and the inlet end  771  of the housing  770  respectively; and, with the vertices  827   c ,  831   c  (i.e., ends of, or direction of, convergence of the sidewalls) thereof directed toward the outlet end  203  of the cartridge  700  and the outlet end  72  of the housing  770  respectively. 
   In addition, the member of the projection/receiver arrangement  741  mounted on the cartridge  700 , in this instance projection member  827 , is provided with a tip  837  that is positioned between the receiver  831  and a portion  839  of the cover  825  when the cartridge  700  is in the installation (or installed) position. For the particular arrangement  741  depicted, tip  837  is positioned on a first side wall of the projection arrangement  741  and projects toward curved side end  732  of cartridge  700  (and away from a second side wall of the projection member  827 ) and is pinched between cover  825  and receiver  831 , to secure projection member  827 , and thus cartridge  700  in place at installation. Still referring to  FIG. 39 , the portion of the projection/receiver arrangement  741  comprising projection member  827  and receiver member  831  will sometimes be referred to herein as a projection/receiver couple  741   a.    
   Referring to  FIG. 39 , it is noted that projection/receiver arrangement  741  includes a second projection/receiver couple  741   b , spaced from couple  741   a  along side  731  of cartridge  700 . This will provide further stabilization. Couple  741  comprises a projection/receiver arrangement including projection member  828  and receiver member  832 , for the example shown each having a “v” or “check” shape with opposite sides. Thus, receiver  832  has sides  832   a  and  832   c  around central vertex  832   b ; and, projection  828  comprises sides  828   a ,  828   c  around central vertex  828   b.    
   It will be understood from the figures that for a typical preferred securing engagement between and among: cartridge  700 ; cover  825 ; and, a remainder of housing  700 ; at least two and typically four couples are provided, two positioned on each side of the cartridge  700 , the opposite sides being mirror images. 
   From  FIGS. 33-41 , then, and above characterizations above regarding them, general principles and observations in accord with the following will be understood. In one aspect, an air cleaner is provide with a housing having a primary filter cartridge housing radial seal surface comprising an interior flange projecting toward an air flow inlet section of the housing. The flange can be configured to define an air flow annulus section or region therearound, within the housing interior and in flow communication with a first air flow annulus around a filter cartridge received within the housing, between the filter cartridge and a housing side wall. In a typical application, the interior flange would have a length of at least 20 mm, typically within the range of 25-35 mm, inclusive and typically not more than 40 mm, and would be typically at least 2.5 mm thick, usually 2.5-4.5 mm thick, inclusive, and typically not more than 5 mm. Also, in some applications the interior flange would have a base end portion directed radially interiorly, with an extension of at least 3 mm, typically 3-7 mm inclusive and typically not more than 7 mm not covered by a filter cartridge housing seal member, when the filter cartridge is installed. 
   The interior flange projecting toward the air flow inlet section can be provided in the housing whether the housing is configured for alternatively receiving two different lengths of filter cartridge, or otherwise. 
   In another or second aspect, an air cleaner assembly is provided including: a housing defining an interior having an air flow inlet section and air flow outlet section; a primary filter cartridge receiving section between the air flow inlet section and the air flow outlet section; and, a primary filter cartridge housing radial seal surface. The radial seal surface may or may not be defined with the interior flange previously discussed. The housing may be configured for possible receipt of only one length (or more than one length) of filter cartridge, as a matter of choice. 
   In this other or second aspect, a first removable and replaceable primary filter cartridge is positioned within the housing. The primary filter cartridge comprises a media pack having an inlet flow face and an opposite outlet flow face. The media pack typically comprises a plurality of flutes extending between the inlet flow face and the opposite outlet flow face. The media pack is closed to passage of unfiltered air therethrough, between the inlet flow face and the outlet flow face. By this it is meant that the air must be filtered, if it enters the inlet flow face and exits the outlet flow face, by passage through the media. The primary filter cartridge includes a housing seal member thereon. In an example shown, the housing seal member is provided with a radial seal portion, member or surface in radial seal engagement with the primary filter cartridge housing radial seal surface. 
   In this other or second aspect, the air cleaner further includes a first projection/receiver arrangement. The first projection/receiver arrangement includes a first receiver member secured to an interior wall of the housing. It typically includes at least first and second (typically non-parallel) side wall sections defining a receiver space therebetween. A first projection member is positioned on the first removable and replaceable primary filter cartridge. It is oriented with at least a portion thereof within the receiver space between the first and second side wall sections of the first receiver member. 
   In an example shown, the first and second side wall sections of the first receiver member are not parallel to one another; and, for example, diverge from one another in extension, for example in extension toward the inlet of the air cleaner. By doing so, they form a pocket or receiver into which the first projection member can tip, or from which it can tip, during installation or removal of the primary filter cartridge. The access cover can be provided within structure, for example a pocket, recess or shoulder arrangement, that inhibits tipping out of receipt within the receiver or pocket, when the access cover is installed. 
   In an example described, the first projection member includes first and second side wall sections non-parallel to one another (i.e., diverging from one another), for example in extension toward the inlet flow face of the first removable and replaceable primary filter cartridge. 
   In an example, the first projection member includes a locking tip thereon directed toward the access cover; the locking tip being positioned between the first receiver member and the inlet flow face of the filter cartridge. Further, in this example, the access cover includes a first receiver pocket oriented with a first locking tip of the first projection member (of the first projection/receiver arrangement) directed therein, when the access cover is in place. As a result, the first receiver pocket of the access cover includes a locking shoulder securing the first locking tip from tipping away from the first receiver member of the first projection/receiver arrangement. The access cover can include pockets or other structure at opposite sides of the cartridge, for such engagement. 
   Although a variety of alternatives are possible, in an example shown the filter cartridge has first and second opposite sides and first and second opposite curved ends; and, the first projection member is positioned on a first side of the cartridge. 
   In an example described, a second projection/receiver arrangement is provided in the air cleaner, with a first receiver member thereon secured to an interior wall of the housing opposite the first receiver member of the first projection/receiver arrangement and with the first removable and replaceable filter cartridge therebetween. The first member of the second projection/receiver arrangement comprises at least first and second side wall sections non-parallel to one another, typically diverging from one another to form a receiver or pocket, for example diverging from one another in extension toward the inlet section; and, a first projection member of the second projection/receiver arrangement is positioned on the first removable and replaceable primary filter cartridge and oriented with at least a portion thereof within the receiver or pocket between the first and second side wall sections of the first receiver member of the second projection/receiver arrangement. 
   The second projection/receiver arrangement can include a tip, for engagement by structure in the access cover, analogous to the tip described for the first projection/receiver arrangement. 
   Also described are filter cartridges having features in general in accord with those characterized above for an air cleaner. For example, the filter cartridge may comprise a media pack having an inlet flow face and an opposite outlet flow face, and comprising a plurality of flutes extending between the inlet flow face and the opposite outlet flow face. The media pack would generally be closed to passage of unfiltered air therethrough, between the inlet flow face and the outlet flow face. A seal member is mounted on the media pack adjacent the outlet flow face and including, in an example shown, radially outwardly directed radial seal member or surface. 
   A preform support is positioned on the media pack adjacent the inlet flow face, the preform support including a first member of a projection/receiver arrangement thereon, the first member including at least first projection member having a least first and second side wall sections typically non-parallel, i.e. diverging from one another, in an example shown in extension toward the inlet flow face. 
   Typically the first member of the first projection/receiver arrangement is positioned on the media pack at a location within 50 mm of the inlet flow face. 
   In still another general statement, a filter cartridge is provided which comprises a media pack as characterized, and a seal member as characterized. A first member of the first projection/receiver arrangement is positioned on the media pack within a location of about 50 mm, typically within 30 mm, of the inlet flow face. The first member includes a first projection member extending outwardly from adjacent the media pack and including at least one of: a first projection wall segment that is directed generally between the inlet face and the outlet flow face; and, a second projection wall segment with a portion directed generally across a direction between the inlet flow face and the outlet flow face. In the specific example shown, the first member of the first projection member includes both. However there is no specific requirement that in all applications of the techniques described herein, both are present, as long as a secure installation position is achievable. Of course a first projection member of a second projection receiver arrangement can be mounted on an opposite side of the filter cartridge. 
   Referring to  FIG. 40 , for the projection/receiver arrangement shown, the receiver member  827  includes a first side  827   a  directed generally between the inlet flow face and the outlet flow face of the filter cartridge. Also, a second wall section  827   b  is depicted, which generally extends across a direction between the inlet flow face and the outlet flow face, in the example shown at an angle of less than 90°, as opposed to directly parallel to the two opposite flow faces. It will be understood from the example shown in  FIG. 40 , that both wall sections can be present. However some stabilization will occur if only one or the other of the wall sections is present. This will be understood from the general descriptions and functions provided previously. 
   A variety of features are described. Variations in them are possible; and, there is no requirement that an arrangement include all of the features described to have some advantage.