WO2005077487A1

WO2005077487A1 - Media arrangement; filter constructions; and, methods

Info

Publication number: WO2005077487A1
Application number: PCT/US2005/004265
Authority: WO
Inventors: Bruce Allen Boehrs; Benny K. Nelson; Robert M. Rogers; William M. Juliar; Steven Scott Gieseke
Original assignee: Donaldson Company, Inc.
Priority date: 2004-02-10
Filing date: 2005-02-09
Publication date: 2005-08-25

Abstract

The z-filter media construction comprising a fluted sheet secured to a non-fluted corrugated sheet is provided. The arrangement can be configured as a media pack in a variety of shapes and sizes of filter arrangements. Methods of preparation and use are described.

Description

MEDIA ARRANGEMENT: FILTER CONSTRUCTIONS; AND. METHODS

Cross-Reference to Related Application

The present application includes the disclosure of, with edits, U.S. Provisional Application 60/543,702 filed February 10, 2004; and U.S. Provisional Application 60/543,804, filed February 11, 2004. The complete disclosure of these two provisional applications is incorporated herein by reference. In addition, to the extent appropriate, request for priority from each of these filings is made. Field of the Disclosure

The present disclosure relates to filter media for use in fluid filtering such as gas (e.g., air) filtration or liquid (lubrication fluid, hydraulic fluid or fuel) filtration. The disclosure particularly concerns z-filter media constructions having a fluted sheet secured to a non-fluted, minor corrugation, sheet.

Background

Filter media as is used in a variety of applications, to filter fluids. Typically the media comprises a non- woven web of fiber, configured as appropriate for the filtration system. A variety of fiber materials have been used, including natural fibers such as cellulose, synthetic fibers such as polyesters or polyolefms, or mixtures of natural fibers and synthetic fibers. In some instances layers of very fine synthetic fibers are attached to the media, see for example U.S. Patent No. 6,673,136 incorporated herein by reference. The media is used for a variety of filter arrangements are generally configured for filtering various fluids, such as: gases (e.g. air) (for example combustion air for intake engine, air directed to compressors or air directed into gas turbine systems); or liquids (for example lubrication (oil) fluids; hydraulic fluids; and/or fuel). There is an increasing interest in using filter media configured in a form generally referenced herein as z-filter media. A z-filter media configuration generally comprises a media having corrugations forming major flutes which extend in the fluid flow direction, secured to a sheet that does not have such major flutes. Such strips are then typically either coiled or separate strips are stacked, to form media arrangements. Examples of arrangements using z-filter media are described for example in U.S. Patent Nos. 5,820,646; 5,895,574; 6,190,432; 6,350,291; and 6,179,890, each of which is incorporated herein by reference. The present disclosure relates to improvements in certain aspects of z-filter media constructions, and, their use in filtering and in filter arrangements.

Summary of the Invention

According to the present disclosure, z-filter media instructions are provided. The instructions include a fluted sheet secured to a corrugated non-fluted sheet. In preferred arrangements, the corrugations of the non-fluted sheet extend generally perpendicularly to the flutes of the fluted sheet. The fluted sheet may also include corrugations extending generally perpendicularly to the flutes. The filter media arrangements according to the present disclosures are described as useable in various media pack configurations including coiled and stacked arrangements. A variety of shapes are possible, including ones having circular cross-sections or oval cross-sections, as examples. Filter arrangements including media packs according to the present disclosure having housing seal arrangements secured to the media packs are also described. In addition, methods of assembly and use are referenced.

Brief Description of the Drawings

Fig. 1 is a fragmentary schematic representation of a z-filter media configuration comprising a fluted sheet having major corrugations therein secured to a non-fluted sheet having minor corrugations therein; the minor corrugations in the non-fluted sheet extending generally perpendicularly to the major corrugations in the fluted sheet. Fig. 2 is an enlarged fragmentary schematic view of a minor corrugation in the arrangement of Fig. 1. Fig. 3 is a fragmentary schematic representation of an inlet flow face of a filter element configured using the z-filter media arrangement of Fig. 1, coiled into a media pack. Fig. 4 is a fragmentary schematic representation showing an opposite, outlet, flow face of the media pack of Fig. 3. Fig. 5 depicts a process for manufacturing a media arrangement according to Fig. 1. Fig. 6 is a schematic perspective view of a coiled z-filter media arrangement according to the present disclosure in a first filter element. Fig. 7 is a schematic perspective view of a coiled z-filter media arrangement according to the present disclosure in a second filter element. Fig. 8 is a schematic perspective view of a stacked media configuration using a z-filter arrangement media according to the present disclosure. Fig. 9 is a side elevational view of a filter element using a coiled z- filter media arrangement according to the present disclosure. Fig. 10 is a top plan view of the filter element of Fig. 9. Fig. 11 is a side elevational view of a further filter element using a z- filter media arrangement according to the present disclosure. Fig. 12 is a top plan view of the filter arrangement of Fig. 11. Fig. 13 is a fragmentary schematic view of a media configuration according to the present disclosure. Fig. 14 is a depiction of various flute arrangements. Fig. 15 is a fragmentary schematic perspective view of an alternate embodiment to that shown in Fig. 4. Detailed Description

A. Advantageous z-Filter Media Configurations - Generally. Attention is first directed to Fig. 1, in which a z-filter media arrangement 1 is depicted. The z-filter media arrangement 1 generally comprises a fluted media sheet 3 secured to a non-fluted sheet 4. Herein the term "fluted media sheet" is meant to refer to a sheet of filter media having major flutes or corrugations extending thereacross in a direction generally corresponding to a direction of flow of fluid through a media pack

(constructed from the media) during filtering. Referring to fluted sheet 3, the major flutes or corrugations are indicated generally at 6, comprising alternating peaks 7 and valleys 8. As will be discussed further below, the alternating peaks 7 and valleys 8 of the major corrugations 6 form inlet and outlet flutes, for passage of fluid to be filtered, through a media pack constructed including z-filter media arrangement 1. Still referring to Fig. 1, the flutes 6 generally extend across fluted sheet 3 from edge 10 to edge 11. For purposes of explanation only, edge 10 will be referred to as the inlet edge and edge 11 is the outlet edge, with respect to flow of fluid through a media pack comprising media 1 during filtering (an opposite direction of flow being possible). The defined general direction of filtering flow is indicated by arrows 12. In general, it can be understood that the fluted sheet 3 includes flutes 6 extending thereacross from a location at or adjacent edge 10 to a location at or adjacent to 11. In general, corrugations will be considered "flutes" in this manner, as long as they are configured and oriented to extend in the direction of liquid flow during filtering, and thus to receive fluid to be filtered in a set of inlet flutes, and to allow for escape of filtered fluid through a corresponding set of outlet flutes, as described below. In general, the fluted sheet 3, Fig. 1, is of a type generally characterized herein as having a "regular, curved, wave pattern" of flutes or corrugations. The term "wave pattern" in this context, is meant to refer to a flute or corrugation pattern of alternating troughs or valleys 8 and ridges or peaks 7. The term "regular" in this context, is meant to refer to the fact that the pairs of valleys and peaks (8, 7) alternate with generally same repeating flute (or corrugation) shape and size. (Also, typically, each valley 8 is substantially an inverse of peak 7). The term "regular" is meant to indicate that the flute (or corrugation) pattern comprises valleys and peaks with each pair (comprising an adjacent valley and peak) repeating, without substantial modification of size and shape of the flutes 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 fluted or corrugated 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 peaks and valleys (7, 8) is necessarily present. The media 3 could be terminated, for example, between a pair comprising a valley and a peak, or partially along a pair comprising a valley or peak. Also, the ends of the valleys and peaks may vary from one another. Such variations at ends are disregarded in the definitions. In the context of the characterization of a "curved" wave pattern of flutes, the term "curved" is meant to refer to a flute pattern that is not the result of a fold or creased shape provided in the media, but rather the apex of each peak 7 and the bottom of each valley 8 is formed along a radiused curve. A typical radius of curvature in peaks and valleys flutes of such z-filter media would be at least 0.25 mm and typically not be more than 3 mm. An additional characteristic of the particular regular, curved, wave pattern of flutes depicted in Fig. 1, for fluted sheet 3, is that approximately at a midpoint between each peak and each valley, along at least most of the length of the flutes, is located in transition region where the general direction of curvature inverts (from convex to concave or concave to convex, depending on the direction). A characteristic of the particular regular, curved, wave pattern of the fluted sheet shown at 3 in Fig. 1, is that the individual flutes 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 10 and 11, the valleys 8 and peaks 7 do not change substantially in cross-section. The term "straight" in reference to fluted pattern as shown in Fig. 1, in part, distinguishes the pattern from tapered flutes of media such as those described in WO 97/40918, the complete disclosure of which is incorporated herein by reference. The tapered flutes of WO 97/40918 would be a curved wave pattern, but not a "regular" pattern or a pattern of straight flutes, as the terms are used herein. For the particular arrangement shown herein in Fig. 1, the parallel flutes 6 are generally straight completely across the media 3, from edge 10 to edge 11. Straight flutes or corrugations can be deformed or folded at selected locations, especially at ends. Modifications of flute ends are generally disregarded in the above definitions of "regular", "curved" and "wave pattern". In general, major corrugations or flutes which form flutes in z-filter media can have a variety of cross-section shapes. Typical ones are indicated in Fig. 14, although alternatives are possible. Dimensions for flutes corresponding to Fig. 14 are found in the following Table A.

In the table, the term "DCI" is meant to refer to flute shapes (DCI A and DCI B) often used by Donaldson Company Inc., the assignee of the present disclosure, in various z-filter media products. Other standard flute definitions provided, are from the corrugation industry. The ratio of flute/flat is meant to refer to the ratio D2/D1 from Fig. 13, with respect to the corrugations of Fig. 14. The term "flat" in this context is simply meant to refer to the shortest distance between adjacent flute valleys, along a flat straight line that is drawn therebetween. The "flute" dimension is meant to refer to the dimension of extension of media along the corrugation, between these same two points. For flutes or major corrugations in z-filter media, flute/flat ratios of at least 1.2 are common, with many having a flute/flat ratio within the range of 1.2 - 2.0, inclusive. This is particularly the case, when a cross-sectional configuration of the flutes is generally in accord with one of the arrangements shown in Fig. 14. Referring to Fig. 13, a typical height (corrugation inside height) corresponding to definition HI, for a flute or major corrugation, it is at least 1 millimeter (mm), typically at least 1.5 mm, usually within the range of 1.5 - 5 mm, inclusive, although alternatives are possible. Alternate flute configurations are possible, including ones that do not have the somewhat sinusoidal shape as shown in the arrangements of Fig. 14, in which flute corrugations are symmetric with respect to the peaks and troughs. In such other arrangements, asymmetry can be introduced in which one set of flutes, for example the flutes forming the peaks have been enlarged, and the other set of flutes, for example the flutes forming the troughs have been made smaller. Arrangements such as these are shown in WO 97/40918 and U.S. Patent No. 5,562,825, incorporated herein by reference. With these flutes, the flute/flat ratio for the relatively large peak can be somewhat greater, and the flute/flat ratio for the narrower troughs can be somewhat smaller. As indicated, in many arrangements, the flutes 6 extend completely across the fluted sheet 3 between opposite edges 10, 11. In other arrangements, they may be folded, crushed, darted or otherwise modified at or near the ends or edges 10, 11, for sealing. Referring still to Fig. 1, flutes 15, defined by troughs 8, are open at edge 10, to receive fluid to be filtered therein. The fluid may comprise air or liquid, for example. Flutes 16, on the other hand, are closed at edge 10 to passage of unfiltered fluid therein. Closure at edge 10 of flute 16 may be generated in a variety of manners. For the particular arrangement 1 depicted, the closure is formed by sealant 18. In the alternative, the closure may be generated by crushing, folding or otherwise distorting the end of flute 16, at this location. Such possibilities are described, for example, in U.S. Provisional applications 60/455,643 filed March 18, 2003; 60/466,026, filed April 25, 2003; and, 60/467,511 filed May 2, 2003; these three provisional applications being incorporated herein by reference in their entirety. In general, flutes 16 are outlet flutes, as will be seen from further description below. That is, a media pack used in a filter element and incorporating z-filter media arrangement 1 would be configured so that unfiltered fluid cannot enter flutes 16, due to closed ends adjacent inlet edge 10. Attention is now directed to edge 11. At edge 11 flutes 15 are closed to passage of unfiltered fluid therefrom. Again a variety of methods can be used for closing flutes 15 adjacent edge 11. For the particular example shown, sealant 19 is positioned to close flutes 15 at this location. Alternatively, crushing, folding or otherwise distorting flutes 15 at or near edge 11 can be done, to cause the closure. This is described, for example, in U.S. Provisional applications 60/455,643; 60/466,026; and 60/467,511, again incorporated herein by reference. On the other hand, adjacent edge 11, flutes 16 are open to passage of filtered fluid therefrom. In use, fluid to be filtered is directed into the inlet edge 10, and into the inlet flutes 15, in the direction of arrows 12. In order to escape from edge 11, the fluid passes through the media into exit flutes 16, with filtering resulting. Z-filter media constructions which operate in this manner are described, for example, in U.S. Patent No. 6,350,291, incorporated herein by reference. Referring to Fig. 1, sheet 25 is meant to indicate an additional extension of non-fluted media 4. In a coiled configuration sheet 25 would comprise a portion of sheet 4 wrapping back around the media. Facing sheet 4 is generally referred to herein as a "non-fluted sheet", because there are no flow flutes therein which extend between the inlet and outlet edges 10, 11 of the media construction 1. That is, while there are corrugations as described below in sheet 4, the corrugations do not extend in a direction between the inlet and outlet edges 10, 11 of the media construction 1. Specifically, and referring to Fig. 1, non-fluted sheet 4 includes minor corrugations 30 therein. The minor corrugations 30 comprise alternating peaks 31 and valleys 32. In general the minor corrugations 30 are configured to extend perpendicularly to the major corrugations 6, when z-filter media arrangement 1 is formed. Attention is now directed to Fig. 2, in which a minor corrugation 40 is depicted, schematically. Corrugation 40 could be any one of corrugations 30, Fig. 1. Referring to Fig. 2, the following dimensions are indicated: T = thickness of media; A = corrugation length; i.e. the distance between the centers of valleys 32 on opposite sides of an identified corrugation 40. B = inside corrugation height; this is the height distortion from flat of corrugation 40 on a concave side 40a thereof. C = total corrugation height to convex side 40b of corrugation 40. In general, C = T+B. As will be apparent from the following, in the schematic of Fig. 2, the relative dimensions and material thicknesses may be shown somewhat exaggerated. For some example arrangements of the type characterized herein, the minor corrugations 40 have the following dimensions: T is ≤ 0.02 inch (< 0.51 mm) typically 0.01 - 0.02 inch (0.25 - 0.51 mm) inclusive; for example, preferably, 0.013 inch or less (0.33 mm or less); A = > 0.12 inch (> 3.0 mm); typically > 0.13 inch (or > 3.3 mm); for example, 0.14 inch - 0.25 inch (3.6 - 6.35 mm), inclusive In some preferred applications A = 0.14 inch - 0.19 inch (3.6 - 4.8 mm) inclusive. B = typically > 0.01 inch (0.25 mm), typically > 0.012 inch (0.3 mm); for example, 0.013 inch - 0.025 inch (0.33 mm - 0.64 mm), inclusive; typically B is < 0.027 inch (0.69 mm). However, B can be made quite small, on the order of 0.002 - 0.006 inch (0.05 - 0.15 mm) if desired. C = T + B. In a more general sense, in a construction in accord with the descriptions herein, it would be preferred to have an inside corrugation height (B) for the minor corrugations, which is sufficiently high to provide for the advantage, but sufficiently small so as to not provide an undesirable profile interfering with media use or flow through the media pack. In addition, it will be preferred to have a corrugation length A (sometimes referred to as cycle length) which is sufficiently small to ensure that the minor corrugations are not simply flattened out, during assembly. In typical arrangements, the corrugation length A (cycle length) for the minor corrugations will be no greater than 0.4 inch (10.2 mm), and typically no greater than 0.38 inch (9.7 mm). Typical lower ranges are discussed above. In some instances, typically wherein the applications require performance under pressures applied to the media of 7.5 inches (63.5 mm) of H₂O up to 30 inches (762 mm) of H₂O, it would be preferred that the corrugation length (A) of the minor corrugations not be greater than 0.3 inch (7.6 mm). As mentioned above, the inside corrugation height (B) of the minor corrugation should not be too high, or, among other things, the facing sheet will interfere with preferred flow and utilization of flute volume within the filter arrangement. Typically the inside corrugation height B should be selected such that a ratio of the inside corrugation height B of the minor corrugations to the inside flute height Hi (Hi = K - thickness of media, Fig. 13) is no greater than 0.1 and typically less. When the corrugated facing sheet and the fluted sheet are pressed together, each compresses at the interface somewhat. It is important that the inside corrugation height (B) of the minor corrugations is sufficiently high, that they do not press so much during engagement, that advantages from use of the minor corrugations in the facing sheet are lost. Typically the minor corrugations would have an inside height of at least 0.00175 inch (0.044 mm). Typical inside corrugation heights (B) are described above. Herein above reference was made to the inside flute height. This will generally be referred to herein as "Hj." When reference is made to the inside flute height, reference is meant to an undistorted flute, in a typical fluted sheet. Referring to Fig. 1, an advantage from using for non-fluted flat sheet

4, a non-fluted sheet having minor corrugations 30 oriented to extend generally perpendicularly to the extension of the major corrugations 6 in the fluted sheet 3, will be understood. In particular fluted sheet 3 will only contact non-fluted sheet 4 at valleys 8 (and peaks when coiled) where the major corrugations 6 touch the peaks 31 or valleys 32 of the minor corrugations 30. This provides for an arrangement with advantageous flow characteristics, for example with respect to restriction to flow fluid through the z-filter arrangement 1. Referring to Fig. 1, spots 45 of tacking adhesive are shown, securing sheets 3 and 4 together at spaced locations. The tacking adhesive can be applied as continuous lines, or as intermittent ones. Attention is now directed to Fig. 3, in which z-filter media arrangement 1 is shown in a coiled construction 50. The coiled construction 50 is presented in a schematic fragmentary view, with the view point directly at upstream inlet end or inlet flow face 51 of the media pack 52. It can be seen that flutes 54, corresponding to major inlet flutes, are open at inlet face 51, and flutes 55, corresponding to major outlet flutes, are closed at inlet end 51. Referring to Fig. 4, an opposite outlet face 57 is depicted in the coiled arrangement 50 of media pack 52. Here inlet flutes 54 are shown closed, and outlet flutes 55 are shown open. Of course, the media pack 52 of Fig. 3 and 4 is shown schematically. Thus, the various major corrugations of the fluted sheet are not shown curved with the cross sections of Fig. 14, and the non-fluted sheet is not shown corrugated in accord with Figs. 1 and 2. The media pack 52 of Figs. 3 and 4, comprises a filter media arrangement of construction 1 of Fig. 1 coiled about itself, with the non-fluted sheet to the outside. Alternatives are possible, as discussed below. Attention is now directed to Fig. 5, which indicates, schematically, formation of z-filter media arrangements, configurations or constructions according to Fig. 1. Referring to Fig. 5, a source roll 60 of non-fluted media is shown being fed through a fluter or corrugator 61, to generate fluted sheet 62. In addition, a source roll 64 of corrugated, non-fluted, media 65 as shown. The corrugations of corrugated media 65 generally correspond to the minor corrugations of a non-fluted sheet. At 67, sheets 62 and 65 are shown brought together. For the particular construction as shown, a sealant bead 70 is shown being positioned between the two sheets, in a center thereof. In addition, various tack beads can be used, to secure the sheets 62, 65 together. At station 72, the corrugated sheet 62 in the region of the bead 70 is darted and slit, slitting be accomplished by slitter 75 through bead 70 to form two strips 76 and 77 corresponding generally to strip 1, Fig. 1, except: in the region of sealant 18, the corrugations will have been darted into a distorted shape; and sealant strip 19 has not yet been applied. Each of the strips 76, 77 can then be moved to stations, where, if desired, sealant strip 19, Fig. 1, can be applied, and the strips, if desired, can be coiled, to form the arrangements of Fig. 3 and 4; or the strips can otherwise be used to manufacture media packs. The process illustrated in Fig. 5, except for the use of corrugated sheet 65, is generally described in U.S. Provisional Patent Applications 60/455,643; 60/466,026; and, 60/467,511 ; the complete disclosures of which are again incorporated herein by reference. Alternate construction methods can be used. Still referring to Fig. 5, it is noted that at 78, an alternate location for applying the sealant strip 70 is shown. Thus, the sealant strip 70 can be applied either to a surface of the non-fluted sheet 65 or to a surface which will become a surface of the fluted sheet 62. Referring now to Fig. 6, a coiled media pack 80 is depicted. In general, a coiled media pack 80 is formed by taking a single strip of z-filter media arrangement 1 having a fluted sheet 3 secured to a non-fluted, corrugated, sheet 4, and coiling the arrangement. Again, in many arrangements the coiling occurs with the non- fluted, corrugated, sheet directed to the outside. In Fig. 6, the media pack

80 is shown in a filter element 81 including a housing seal arrangement 82 on the media pack 80. A housing seal arrangement 82 provides for a seal between element

81 and an air clear (or fluid filter) housing when element 81 is installed for use. Referring to Fig. 6, the particular media pack 80 depicted is generally circular (in cross-section) and thus is cylindrical in shape, although alternatives are possible. It is noted that the media pack 80 could be encased to a sheath, if desired. Attention is now directed to Fig. 7, in which a filter element 90 is depicted. The filter element 90 comprises a coiled media pack 91 comprising z- filter media arrangement 1 configured in a coiled form. The filter element 90 includes a housing seal arrangement 92 thereon, attached to the media pack 91. In Fig. 7, the coiled media pack 91 is shown in an oval form having opposite curved ends 94 and 95. The particular oval shape depicted has opposite sides 96 and 97 which are generally straight. Alternatives are possible, for example, in which opposite sides 96 and 97 are somewhat curved. If desired, media pack 91 could be encased in a sheath. Attention is now directed to Fig. 8 in which a media pack 100 is depicted comprising strips or z-filter media 1 stacked on one another, instead of coiled. Various housing seal arrangements can be attached to stack 1, including arrangements similar to those in Figs. 6 and 7. Attention is now directed to Fig. 9 in which a filter element 110 is depicted comprising media 111 (corresponding preferably to a coil of z-filter media arrangement 1, Fig. 1) having secured thereto a seal arrangement 112. The seal arrangement can in general be in accord with U.S. Provisional Application entitled "Seal Arrangement For Filter Element; Filter Element Assembly; And, Methods", filed December 22, 2003 by Schrage et al, and thus comprise a seal material 113 mounted on a framework 114, Fig. 10. The seal arrangement 113 also provides a joint seal 115 to the media pack 111. Referring to Fig. 10, the particular filter element 110 depicted has an oval shape with opposite curved ends 120, 121, and opposite sides 122, 123; in this instance, the oval shape having relatively straight sides 122, 123. Of course, alternatives are possible. Referring to Fig. 9, tack seal 124 is shown sealing a tail end to the media in the coil. Structure 125 at an opposite end of the media pack 111 from the seal arrangement 112, provides for engagement with a housing during use. Grid 126 extends across a flow face 127 of the media pack 111. Typically, flow face 127 is an outlet flow face; with opposite face 128 being an inlet flow face, although alternatives are possible. The media pack 111 can be encased in a sheath, if desired.. Attention is now directed to Fig. 11, in which filter element 130 is depicted comprising: media pack 131, preferably corresponding to z-filter media arrangement 1, Fig. 1, seal arrangement 132 and structure 133, with like parts being generally analogous to those parts and Figs. 9 and 10. The element 130 of Fig. 11, as shown in top view in Fig. 12 is generally circular in configuration. Again, grid work 135 extends across a flow face 136 of the media pack 131. The opposite flow face 137 typically has no grid thereacross, but does have structure 138. The media pack 130 could be enclosed within an impermeable sheath, if desired. B. Alternate Embodiment - Additionally Using a Minor Corrugated Sheet as the Fluted Sheet.

Referring to Fig. 1, for the particular z-filter media arrangement depicted, for fluted sheet 3 a material which is not corrugated perpendicularly to the flute direction was used. In the alternative, a sheet having minor corrugations extending perpendicularly to the flute direction can be used in the z-filter media arrangement. The minor corrugations would generally, and preferably, be defined similarly to the minor corrugation of sheet 4 discussed above in connection with Fig. 2. Such an arrangement is depicted schematically in Fig. 15. In which z-filter media arrangement 200 comprises fluted sheet 221 secured to non-fluted corrugated sheet 222. Here the fluted sheet 221 includes minor corrugations 225 extending perpendicularly to the major flutes or major corrugations 226. The minor corrugations 225 may have a definition similar to corrugation 4, Fig. 2. This configuration can be used to create advantageously low restriction to fluid flow between opposite inlet and outlet edges 130, 131, respectively, when the z-filter media arrangement 200 is used in a media pack. The z-filter media arrangement 200 can be used in a variety of media packs, including for example, the ones shown in the Figs, discussed above.

Claims

WE CLAIM:

1. A filter media pack comprising: (a) a fluted sheet of media having an inlet edge and an outlet edge and defining a set of inlet flutes and outlet flutes; and (b) a corrugated, non-fluted facing sheet of media secured to the fluted sheet of media with the corrugations of the non-fluted sheet extending perpendicularly to the flutes of the fluted sheet; (i) the corrugations in the non-fluted sheet having an inside corrugation height B and the fluted sheet having an inside flute height H;; the media pack being such that a ratio B/Hj is no greater than 0.1.

2. A filter media pack according to claim 1, wherein: (a) the corrugations of the non-fluted sheet have an inside corrugation height of no greater than 0.64 mm.

3. A filter media pack according to claim 2, wherein: (a) the corrugations of the non-fluted sheet having a corrugation length of at least 3.0 mm; and, a corrugation height of 0.33 mm to 0.64 mm, inclusive.

4. A filter media pack according to claim 3, wherein: (a) the flutes of the fluted sheet have a corrugation height of at least 1 mm.

5. A filter media pack according to claim 4, wherein: (a) the flutes of the fluted sheet have a flute/flat ratio of at least 1.2.

6. A filter media pack according to claim 5, wherein: (a) the fluted sheet comprises corrugations extending perpendicularly to the flutes.

7. A filter media pack according to claim 1, wherein: (a) the fluted sheet and non-fluted sheet are coiled together to form the media pack.

8. A filter media pack according to claim 7, wherein: (a) the media pack is circular in cross-section.

9. A filter media pack according to claim 7, wherein: (a) the media pack is oval in cross-section.

10. A filter media pack according to claim 7, wherein: (a) a housing seal arrangement is secured to the media pack.

11. A filter media pack according to claim 1 , wherein: (a) the media pack comprises a stacked arrangement.

12. A filter media pack comprising: (a) a fluted sheet of media having an inlet edge and an outlet edge and defining a set of inlet flutes and outlet flutes; and, (b) a corrugated, non-fluted facing sheet of media secured to the fluted sheet of media with the corrugations of the non-fluted sheet extending perpendicularly to the flutes of the fluted sheet; (i) the corrugations of the non-fluted sheet have an inside corrugation height of no greater than 0.64 mm.