Patent Description:
Z-flow filter media, such as that described in <CIT> to inventor Rocklitz, has a plurality of layers of media. Each layer has a fluted sheet, a facing sheet, and a plurality of flutes extending from a first face to a second face of the filtration media pack. A first portion of the plurality of flutes are closed to unfiltered air flowing into the first portion of the plurality of flutes, and a second portion of the plurality of flutes are closed to unfiltered air from flowing out of the second portion of the plurality of flutes. Air passing into flutes on one face of the media pack passes through filter media before flowing out flutes on the other face of the media pack. <CIT> discloses a filter element including a first filter media pack with an inlet face and an outlet face and a second filter media pack with an inlet face and an outlet face. <CIT> discloses a method of manufacturing a body comprising the steps of forming a single strip of material with at least one plain region and at least one region of protrusions, such as corrugations, bumps or ridges.

Although z-flow media has many benefits, a need remains for improved filter performance, including filter media, media packs, and elements with reduced pressure loss across the element and/or improved particulate loading capacity.

The invention relates to an air filtration media pack according to claim <NUM>, a tilter element according to claim <NUM> and a method according to claim <NUM>. The present application relates to filter media, filter media packs, filter elements, and air cleaners with two or more different media configurations, plus methods of making and using the media, media packs, filter elements, and air cleaners. The different media configurations can be, for example, different flute geometries in a z-flow filter media. The use of two or more different media configurations allows for improved performance, such as reduced pressure loss and/or increased loading capacity, relative to the use of a single media configuration.

In example implementations two different media sections are combined into a single filter element, the two media sections having distinct pressure loss and loading properties. The distinction in pressure loss and loading properties between the media sections will generally be less than normal variation observed within filter elements from manufacturing variations, thus the difference will be at least <NUM> percent for a specific measured and varied parameter, and more typically at least <NUM> percent for a specific measured and varied parameter.

In an example configuration the first media section has a lower initial pressure loss than the second media section, while the second media section has a greater dust holding capacity than the first media section. In certain constructions the combination of these two media sections results in an element that has better performance than would be achieved with a media pack made only of one of these media alone, and better than would be achieved by just averaging the performance of each media sections. Thus, the hybrid filter element can (for example) demonstrate reduced initial pressure loss but also increased loading relative to media packs made with just one media or the other media.

Flute height, for example, can be varied so that individual layers of media have varied height, multiple layers of media have different heights, or larger sections of media have different heights.

Flow through these various layers and sections of media is typically a parallel flow. As used herein, the term "parallel" refers to a construction in which a fluid stream to be filtered diverges into the first and second plurality of flutes, and then typically converges again later. As such, "parallel" does not require that the flutes themselves be arranged in a geometrically parallel configuration (although they often are), but rather that the pluralities of flutes exhibit parallel flow with regard to one another. Thus, "parallel" flow is used in contrast to "serial" flow (where the flow is from one plurality of flutes and then into a second plurality of flutes in serial flow).

Constructions made in accordance with the disclosures herein can, for example, allow for improvements in both pressure loss and dust loading relative to filter media packs and elements that are made of a single media type. In addition, in some implementations it is possible to add more media into a prescribed volume without significantly increasing initial pressure loss. As such, a media construction can be created that has a relatively low initial pressure loss while still having a relatively high dust loading capacity. This improvement can be obtained by combining a first media that has a low initial pressure loss (but low dust loading capacity) with a second media that has a higher initial pressure loss (and higher dust loading capacity). The resulting combined media demonstrates, in some embodiments, an initial pressure loss similar to the first media but with the dust loading of the second media.

It is also possible to utilize the benefits of the hybrid media constructions to get more media in a specific volume, as well as to load more dust on a given media surface area. Thus, it is possible to get improved media performance while having less media.

In example constructions the first media pack can comprise, for example, approximately <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> percent of the media pack (measured by pack volume); and the second media pack can comprise, for example, approximately <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or <NUM> percent of the media pack (measured by pack volume). As used herein, pack volume means the total volume occupied by the media pack when measuring that area contained within the perimeter of the pack. Thus, pack volume can include the media itself, as well as the open upstream volume into which dust can load and the downstream volume through which the filtered air travels out of the media pack. Alternatively, the first plurality of flutes comprises from <NUM> to <NUM> percent of the pack volume, and the second plurality of flutes comprises from <NUM> to <NUM> percent of the pack volume. In other implementations the first plurality of flutes comprises from <NUM> to <NUM> percent of the pack volume, and the second plurality of flutes comprises from <NUM> to <NUM> percent of the pack volume. In yet another implementation the first plurality of flutes comprises from <NUM> to <NUM> percent of the inlet face of the media pack, and the second plurality of flutes comprises from <NUM> to <NUM> percent of the pack volume.

In such example constructions the first media pack can be, for example, approximately <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> percent of the media pack (measured by media surface area); and the second media can be, for example, approximately <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or <NUM> percent of the media pack (measured by media surface area). As used herein, pack surface area means the total surface area of the media in each media pack if the media pack was taken apart and the media stretched out. Alternatively, the first plurality of flutes comprises from <NUM> to <NUM> percent of the media surface area, and the second plurality of flutes comprises from <NUM> to <NUM> percent of the media surface area. In other implementations the first plurality of flutes comprises from <NUM> to <NUM> percent of the inlet face of media surface area, and the second plurality of flutes comprises from <NUM> to <NUM> percent of the media surface area pack. In yet another implementation the first plurality of flutes comprises from <NUM> to <NUM> percent of the media surface area, and the second plurality of flutes comprises from <NUM> to <NUM> percent of the media surface area. It is also possible to characterize media packs by the portion of the inlet face occupied by a specific media type. In some implementations the first media pack (comprising a first plurality of flutes) comprises from <NUM> to <NUM> percent of the inlet face of the media pack, such as <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or <NUM> percent of the inlet face of the media pack; and the second media pack (comprising a second plurality of flutes) comprises from <NUM> to <NUM> percent of the inlet face of the media pack, such as <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or <NUM> percent of the inlet face of the media pack. Alternatively, the first plurality of flutes comprises from <NUM> to <NUM> percent of the inlet face of the media pack, and the second plurality of flutes comprises from <NUM> to <NUM> percent of the inlet face of the media pack. In other implementations the first plurality of flutes comprises from <NUM> to <NUM> percent of the inlet face of the media pack, and the second plurality of flutes comprises from <NUM> to <NUM> percent of the inlet face of the media pack. In yet another implementation the first plurality of flutes comprises from <NUM> to <NUM> percent of the inlet face of the media pack, and the second plurality of flutes comprises from <NUM> to <NUM> percent of the inlet face of the media pack.

Another embodiment of the filtration media pack includes a third plurality of flutes arranged in parallel flow with the first and second plurality of flutes; wherein the first, second, and third plurality of flutes exhibit regular repeating differences in flute shape, flute size, flute height, flute width, cross-flute area, or filter media. Optionally each of the first, second, and third pluralities of flutes is arranged in a separate plurality of layers. It will be understood that in some implementations more than three pluralities of flutes arranged in parallel flow, wherein each of the plurality of flutes exhibit differences in flute shape, flute size, flute height, flute width, cross-flute area, or filter media. Frequently these differences in flute properties are repeating, often regularly repeating.

In an example construction having three types of flutes, the first, second, and third flutes can be selected such that the first plurality of flutes comprises <NUM> to <NUM> percent of the volume of the media pack, such as <NUM>, <NUM>, <NUM>, or <NUM> percent the volume of media pack; the second plurality of flutes comprises <NUM> to <NUM> percent the volume of the pack, such as <NUM>, <NUM>, <NUM> or <NUM> percent of the volume of media pack; and the third plurality of flutes comprises <NUM> to <NUM> percent of the volume of the media pack, such as <NUM>, <NUM>, <NUM> or <NUM> percent of the volume of the media pack.

In an example construction having three types of flutes, the first, second, and third flutes can be selected such that the first plurality of flutes comprises <NUM> to <NUM> percent of the media surface area of the media pack, such as <NUM>, <NUM>, <NUM>, or <NUM> percent of the media surface area of the filter media pack; the second plurality of flutes comprises <NUM> to <NUM> percent of the media surface area of the media pack, such as <NUM>, <NUM>, <NUM> or <NUM> percent of the media surface area of the media pack; and the third plurality of flutes comprises <NUM> to <NUM> percent of the media surface area of the media pack, such as <NUM>, <NUM>, <NUM> or <NUM> percent of the surface area of the media pack.

In an example construction having three types of flutes, the first, second, and third flutes can be selected such that the first plurality of flutes comprises <NUM> to <NUM> percent of the inlet face of the media pack, such as <NUM>, <NUM>, <NUM>, or <NUM> percent of the inlet face of the filter media pack; the second plurality of flutes comprises <NUM> to <NUM> percent of the inlet face of the media pack, such as <NUM>, <NUM>, <NUM> or <NUM> percent of the inlet face of the filter media pack; and the third plurality of flutes comprises <NUM> to <NUM> percent of inlet face of the media pack, such as <NUM>, <NUM>, <NUM> or <NUM> percent of the inlet face of the media pack.

An example air filtration media pack has a plurality of layers of fluted z-flow media. In some constructions each layer of media has a facing sheet and a fluted sheet. Each fluted sheet includes a plurality of flutes which exhibit regular repeating differences in flute shape, flute size, flute height, flute width, cross-flute area, or filter media. These pluralities of flutes are arranged and a parallel flow pattern. The facing sheet can be, for example, constructed of the same material forming the fluted sheet, or can be constructed of a different material. The facing sheet is typically not fluted, but can be fluted in some constructions. The facing sheet can possess filtration properties, or be a non-filtration material without filtration properties (such as a spacer material). Also, the facing sheet can cover all or only a portion of each fluted sheet. The facing sheet can be continuous or segmented such that separate facing sheet segments are positioned against each facing sheet.

The different media types in the plurality of flutes are in parallel flow to one another. As noted above, as used herein the term "parallel" refers to a construction in which a fluid stream to be filters diverges into the first and second plurality of flutes, and then typically converges again later. As such, "parallel" does not require that the flutes themselves be arranged in a geometrically parallel configuration (although they often are), but rather that the pluralities of flutes have generally parallel flow with regard to one another. Thus, "parallel" flow is used in contrast to "serial" flow where the flow is from one plurality of flutes and then into a second plurality of flutes. It will be understood that, in some constructions such as a wrapped construction, the fluid flow may be between adjacent sections of filter media.

The media can be arranged within a media pack in a variety of constructions, including alternating single face layers (for example, construction A/B/C/A/B/C. where A, B, and C each refer to distinct flute types, and "/" denotes separate layers. Thus, A/B/C/A/B/C. refers to a fluted media with a first layer of flutes having configuration A, followed by second layer of flutes having configuration B, and third layer of flutes having configuration C. This order is repeated for layers four, five and six in the A/B/C/A/B/C arrangement. This A/B/C arrangement can be repeated numerous times to create the full media pack.

The use of the terms "A", "B", and "C" flutes is meant to represent medias with different properties. For example, flutes of type A may have a greater height than flutes of type B or type C; or flutes of type B may have a greater or lesser width than flutes of type A or type C; or flutes of type A can be formed of media with greater efficiency and/or permeability than flutes of type B or C.

It will also be understood that the media can be arranged in constructions where layers of similar flutes are grouped together, such as a media pack with the construction A/A/A/A/B/B/B/C/C/C. In this construction there are four layers with A flutes, three layers with B flutes, and three layers with C flutes. Each of the layers with types of flutes A, B, and C are grouped together. The different media areas containing different types of flutes can directly contact one another, such as by being arranged in a stacked or wrap configuration. They also be arranged so that the different media areas are separated by a divider or other component.

It will also be understood that there can be many more than three or four layers of similar flutes grouped together depending upon flute size, media pack size, etc. A media pack may be constructed with many layers of each media, such as (for example), ten, twenty, thirty or forty grouped layers A flutes; or ten, twenty, thirty or forty grouped layers of B flutes, etc..

In some constructions flutes can be varied repeatedly within a layer as well as between layers. For example, a media pack having the construction ABC. has layers with repeating flutes A, flutes B and flutes C alternating with layers having flutes D, flutes E, and flutes F. Other examples, without limitation, include a media pack with AB. /CDEF; a media pack with A.

Using more than one flute configuration within a given filter media pack or air cleaner can provide various benefits, including having a lower initial restriction of one flute configuration and the dust holding capacity of a second flute configuration. Thus, elements formed of the combined media can outperform elements formed solely of one flute configuration. In this manner combining different types and styles of flute geometries allows improvements in one or more of cost, initial pressure loss, loading capacity, or other aspects of filter performance.

In some constructions the relative position of the media is determined by desired element properties. For example, higher permeability media can be arranged in areas of a filter element that has highest face velocity due to configuration of an air cleaner in which it is placed so as to reduce initial restriction. In other embodiments, higher efficiency media is arranged in areas with the highest face velocity to improve initial efficiency of the filter element.

This summary is an overview of some of the teachings of the present application and is not intended to be an exclusive or exhaustive treatment of the present subject matter. Further details are found in the detailed description and appended claims. Other aspects will be apparent to persons skilled in the art upon reading and understanding the following detailed description and viewing the drawings that form a part thereof, each of which is not to be taken in a limiting sense. The scope herein is defined by the appended claims.

Aspects may be more completely understood in connection with the following figures, in which:.

The present application is directed, in an example embodiment, to an air filtration media pack comprising a plurality of layers of fluted media, each layer comprising a first plurality of flutes and a second plurality of flutes, the first and second plurality of flutes being arranged in a parallel flow configuration; wherein the first and second plurality of flutes exhibit differences in flute shape, flute size, flute height, flute width, cross-flute area, or filter media.

These pluralities of flutes are arranged in parallel flow. As noted above, as used in this context, the term "parallel" refers to a construction in which a fluid stream to be filtered diverges into the first and second plurality of flutes, and then typically converges again later. As such, "parallel" does not require that the flutes themselves be arranged in a geometrically parallel configuration (although they often are), but rather that the pluralities of flutes exhibit parallel flow with regard to one another. Thus, "parallel" flow is used in contrast to "serial" flow (where the flow is from one plurality of flutes and then into a second plurality of flutes in serial flow).

According to the invention, the first plurality of flutes is arranged in a first plurality of layers, and the second plurality of flutes is arranged in a second plurality of layers of the fluted media.

Disclosed herein, two different media packs are combined into a single filter element, the two media packs having distinct pressure loss and loading properties. In an example the first media pack has a lower initial pressure loss than the second media pack, while the second media pack has a greater dust holding capacity than the first media pack. In certain constructions the combination of these two media results in an element that has better performance than would be achieved with either media alone, and better than would be achieved by just averaging the performance of each media pack. Thus, the hybrid filter element can (for example) demonstrate reduced initial pressure flow but also increased loading.

In example constructions the first media pack can be, for example, approximately <NUM>, <NUM>, <NUM>, or <NUM> percent of the media pack (measured by pack volume); and the second media pack can be, for example, approximately <NUM>, <NUM>, <NUM>, or <NUM> percent of the media pack (measured by pack volume). As used herein, pack volume means the total volume occupied by the media pack when measuring that area contained within the perimeter of the pack. Thus, pack volume can include the media itself, as well as the open volume into which dust can load.

In such example constructions the first media pack can be, for example, approximately <NUM>, <NUM>, <NUM>, or <NUM> percent of the media pack (measured by media surface area); and the second media pack can be, for example, approximately <NUM>, <NUM>, <NUM>, or <NUM> percent of the media pack (measured by media surface area). As used herein, pack surface area means the total surface area of the media in each media pack if the media pack was taken apart and the media stretched out.

In some implementations the first plurality of flutes comprises from <NUM> to <NUM> percent of the inlet face of the media pack, and the second plurality of flutes comprises from <NUM> to <NUM> percent of the inlet face of the media pack. Alternatively, the first plurality of flutes comprises from <NUM> to <NUM> percent of the inlet face of the media pack, and the second plurality of flutes comprises from <NUM> to <NUM> percent of the inlet face of the media pack. In other implementations the first plurality of flutes comprises from <NUM> to <NUM> percent of the inlet face of the media pack, and the second plurality of flutes comprises from <NUM> to <NUM> percent of the inlet face of the media pack. In yet another implementation the first plurality of flutes comprises from <NUM> to <NUM> percent of the inlet face of the media pack, and the second plurality of flutes comprises from <NUM> to <NUM> percent of the inlet face of the media pack.

Another embodiment of the filtration media pack includes a third plurality of flutes arranged in parallel flow with the first and second plurality of flutes; wherein the first, second, and third plurality of flutes exhibit regular repeating differences in flute shape, flute size, flute height, flute width, cross-flute area, or filter media. Optionally each of the first, second, and third pluralities of flutes is arranged in a separate plurality of layers. It will be understood that in some implementations more than three pluralities of flutes arranged in parallel flow, wherein each of the plurality of flutes exhibit regular repeating differences in flute shape, flute size, flute height, flute width, cross-flute area, or filter media.

In an example construction having three types of flutes, the first, second, and third flutes can be selected such that the first plurality of flutes comprises <NUM> to <NUM> percent of the inlet face of the media pack; the second plurality of flutes comprises <NUM> to <NUM> percent of the inlet face of the media pack; and the third plurality of flutes comprises <NUM> to <NUM> percent of inlet face of the media pack.

In another example construction having three types of flutes, the first, second, and third flutes can be selected such that the first plurality of flutes comprises <NUM> to <NUM> percent of the inlet face of the media pack; the second plurality of flutes comprises <NUM> to <NUM> percent of the inlet face of the media pack; and the third plurality of flutes comprises <NUM> to <NUM> percent of inlet face of the media pack.

In come implementations the plurality of layers of single facer media are arranged in a wound configuration, while in other implementations the facer media is arranged in a stacked configuration.

In some configurations the first and second plurality of layers of single facer media are arranged in an intermixed configuration with one more layers of the first plurality of single facer media alternating with one or more layers of the second plurality of single facer. In example implementations with at least three kinds of sing facer media, the first and second plurality of layers of single facer media are arranged in an intermixed configuration with one more layers of the first plurality of single facer media alternating with one or more layers of the second plurality of single facer media and one or more layers of the third plurality of single facer media. Also, when three types of media are used, the first, second, and third plurality of layers of single facer media can be arranged in an intermixed configuration with one more layers of the first plurality of single facer media alternating with one or more layers of the second plurality of single facer media and one or more layers of the third plurality of single facer media. In some implementations, more than three types of filter media are used, and these different types of media can be incorporated either in an intermixed manner or a manner in an aggregated manner in which the different types of media are collected together without intermixing between types of media. Alternatively, the media can be aggregated into smaller groups and then intermixed, such as by having five layers of one media and three layers of a different media.

Now, in reference to the drawings, further aspects of the filter media, media packs, and elements will be identified.

First, regarding <FIG>, a perspective view of an example filter element <NUM> is shown. The example filter element <NUM> includes an inlet <NUM>, an outlet <NUM> on the opposite side of the element <NUM> from the inlet <NUM>, and wound z-flow media <NUM> within the element <NUM>. A seal <NUM> is shown surrounding the inlet <NUM>, and a support frame <NUM> is depicted. It will be appreciated as well that the filtration element can have flow opposite to that shown in <FIG>, such that the inlet <NUM> and outlet <NUM> are reversed.

<FIG> is an enlarged schematic, cross-sectional view of a section of single facer filter media <NUM> suitable for use in filter media packs and filter elements as described herein. The single facer media <NUM> includes fluted sheet <NUM>, along with a top facer sheet <NUM> and a bottom facer sheet <NUM>. The fluted sheet <NUM> includes a plurality of flutes <NUM>. A fluid stream to be filtered, such as air for an internal combustion engine, enters flutes <NUM> along flow path <NUM>, and then travels along the flutes until passing through the filter media and out a different flute along fluid flow path <NUM>. This fluid flow through fluted media packs is described in, for example, <CIT>.

<FIG> is an enlarged front view of a sheet of fluted media with a fluted sheet <NUM>, top facer sheet <NUM> and facer media <NUM> constructed and arranged according to an embodiment of the invention is shown with dimensions of example flutes. The fluted sheet <NUM> includes flutes <NUM>. The flutes <NUM> in the depicted embodiment have a width A measured from a first one peak to adjacent peak. In example embodiments width A is from. <NUM> inches, optionally from. <NUM> inches, and optionally from. <NUM> inches. The flutes <NUM> also have a height B measured from adjacent same size peaks. The flute <NUM> has an area between fluted sheet <NUM> and facing sheet <NUM>, measured perpendicular to the flute length. The area can vary depending along the length of the flute when the height, width or shape of the flute varies along its length, such as when the flute tapers.

<FIG> is a top schematic view of an example filter media pack <NUM> for use in a filter element. The filter media pack <NUM> has two types of filter media: first media <NUM> and second media <NUM>. The media is shown in a wound configuration with the two types of filter media intermixed and overlapping. The filter media <NUM> and <NUM> is shown in schematic form, without showing the actual flutes of the media. The filter media pack <NUM> can typically be formed by winding of different types of media simultaneously around a central axis. In this example embodiment the ratio of face area of media <NUM> to <NUM> is approximately <NUM>:<NUM>.

<FIG> is a top schematic view of an example filter media pack <NUM>, showing a wound configuration with three types of filter media. The filter media pack <NUM> has three types of filter media: first media <NUM>, a second media <NUM>, and a third media <NUM>. The media is shown in wound configuration with the three types of filter media intermixed and overlapping. The filter media <NUM>, <NUM> and <NUM> is shown in schematic form, without showing the actual flutes of the media. The filter media pack <NUM> can typically be formed by winding three different types of media simultaneously around a central axis. In this example embodiment the ratio of face area of media <NUM> to <NUM> to <NUM> is approximately <NUM>:<NUM>:<NUM>.

<FIG> is a top schematic view of an example filter media pack <NUM>, showing a stacked configuration with two types of flutes. The filter media pack <NUM> has two types of flutes: first flutes <NUM> and second flutes <NUM>.

<FIG> is a top schematic view of an example filter media pack <NUM>, showing a stacked configuration with different types of filter media. The filter media pack <NUM> has three types of flutes: first flutes <NUM>, second flutes <NUM>, and third flutes <NUM>.

<FIG> is a top schematic view of an example filter media pack <NUM>, showing a stacked configuration with different types of flutes. The filter media pack <NUM> has two types of flutes: first flutes <NUM> and second flutes <NUM>.

<FIG> is a top, schematic view of an example filter media pack <NUM>, showing a stacked configuration with three types of filter media. The three types of filter media are first media <NUM>, a second media <NUM>, and a third media <NUM>. The media is shown in a stacked configuration with the three types of filter media being segregated by media type rather than intermixed. In this example embodiment the ratio of filter media <NUM> to <NUM> to <NUM> is approximately <NUM>:<NUM>:<NUM>, based upon pack entrance area.

<FIG> is a top schematic view of an example filter media pack <NUM>, showing a stacked configuration with two types of filter media: first media <NUM> and second media <NUM>. The media is shown in stacked configuration with the two types of filter media separate rather than intermixed. In this example embodiment the ratio of filter media <NUM> to <NUM> is approximately <NUM>:<NUM>, based upon total pack entrance area.

<FIG> is a top schematic view of an example filter media pack <NUM>, showing a stacked configuration with two types of filter media: first media <NUM> and second media <NUM>. The media is shown in stacked configuration. In this example embodiment the ratio of filter media <NUM> to <NUM> is approximately <NUM>:<NUM>, based upon total pack entrance area.

<FIG> is a top schematic view of an example filter media pack, showing a stacked configuration with two types of filter media. The filter media pack <NUM> has two types of filter media: first media <NUM> and second media <NUM>. The media <NUM> and <NUM> is stacked with five layers of filter media <NUM> alternating with two layers of media <NUM>.

<FIG> is a top schematic view of an example filter media pack, showing a stacked configuration with two types of filter media. The filter media pack <NUM> has two types of filter media: first media <NUM> and second media <NUM>. The media is shown in stacked configuration. The media <NUM> and <NUM> is stacked with two layers of filter media <NUM> alternating with one layer of media <NUM>.

<FIG> is a top schematic view of an example filter media pack <NUM>, showing a stacked configuration with two types of filter media. The filter media pack <NUM> has two types of filter media: first media <NUM> and second media <NUM>. The media <NUM> and <NUM> are stacked, with one layer of filter media <NUM> alternating with one layer of media <NUM>.

<FIG> is a top schematic view of an example filter media pack <NUM>. The filter media pack <NUM> has three types of filter media: first media <NUM>, second media <NUM>, and third media <NUM>. The media layers <NUM>, <NUM> and <NUM> are arranged in an alternating stack.

<FIG> is a top schematic view of an example filter media pack <NUM>, showing a wound configuration with two types of filter media <NUM> and <NUM>. The media is wound with the first media <NUM> on the inside and the second media <NUM> on the outside, the first and second medias <NUM>, <NUM> spliced together.

<FIG> is a top schematic view of an example filter media pack <NUM>, showing a wound configuration with three types of filter media <NUM>, <NUM>, and <NUM>. The media is wound with a first media <NUM> on the inside, the second media <NUM> in the middle, and the third media <NUM> on the outside. The first and second medias <NUM>, <NUM> are spliced together, as are the second and third medias <NUM>, <NUM>.

<FIG> is a top, partial schematic view of an example filter media pack <NUM>, showing a stacked configuration with three types of filter media. The three types of filter media are first media <NUM>, second media <NUM>, and third media <NUM>. The media is shown in a stacked configuration with the three types of filter media being segregated by media type rather than intermixed. In this example embodiment the ratio of filter media <NUM> to <NUM> to <NUM> is approximately <NUM>:<NUM>:<NUM>, based upon total pack entrance area.

<FIG> is a top schematic view of an example filter media pack <NUM>, showing a stacked configuration with two types of filter media: first media <NUM> and second media <NUM>. The media is shown in a stacked configuration with the two types of filter media segregated. In this example embodiment the ratio of filter media <NUM> to <NUM> is approximately <NUM>:<NUM>, based upon total pack entrance area.

<FIG> is a top schematic view of an example filter media pack <NUM>, showing a stacked configuration with two types of filter media. The filter media pack <NUM> has two types of filter media: first media <NUM> and second media <NUM>. The media is shown in stacked configuration. In this example embodiment the ratio of filter media <NUM> to <NUM> is approximately <NUM>: <NUM>, based upon total pack entrance area.

<FIG> is a top schematic view of an example filter media pack <NUM>, showing a stacked configuration with two types of filter media. The filter media pack <NUM> has two types of filter media: first media <NUM> and second media <NUM>. The media pack <NUM> has six layers of filter media <NUM> alternating with two layers of media <NUM>.

<FIG> is a top schematic view of an example filter media pack <NUM>, showing a stacked configuration with two types of filter media. The filter media pack <NUM> has two types of filter media: first media <NUM> and second media <NUM>. The media pack <NUM> has two layers of filter media <NUM> alternating with one layer of media <NUM>.

<FIG> is a top, partial schematic view of an example filter media pack <NUM>, showing a stacked configuration with two types of filter media. The two types of filter media are first media <NUM> and a second media <NUM>. The media is shown in a stacked configuration with the two types of filter media intermixed.

<FIG> is a top, partial schematic view of an example filter media pack <NUM>, showing a stacked configuration with three types of filter media. The three types of filter media are first media <NUM>, a second media <NUM>, and a third media <NUM>. The media is shown in a stacked configuration with the three types of filter media intermixed.

<FIG> is a top schematic view of an example filter media pack <NUM>, showing a wound configuration with two types of filter media: first media <NUM>, and second media <NUM>. The media is shown in a wound configuration with the two types of media distinct from one another by having filter media <NUM> laid down first, and then filter media <NUM> laid down second. In this example embodiment the ratio of pack entrance area. <NUM> to <NUM> is approximately <NUM>:<NUM>. This construction can be created by, for example, wrapping a first singleface media type for a period, cutting that web and splicing a second singleface media type to the end region of the first single face media type, continuing the wrapping process, and repeating for as many singleface media types as desired. Alternatively, winding of each singleface media type can be done separately, and the sections can be brought together and sealed as a secondary process.

<FIG> is a top schematic view of an example filter media pack <NUM>, showing a wound configuration with two types of flutes forming the filter media. The filter media pack <NUM> has two types of flutes: first media <NUM>, and second media <NUM>. The media is shown in wound configuration with the two types of flutes separated from one another. In this example embodiment the ratio of pack entrance area <NUM> to <NUM> is approximately <NUM>:<NUM>.

<FIG> is a top schematic view of an example filter media pack <NUM>, showing a wound configuration with three types of filter media: first media <NUM>, second media <NUM>, and third media <NUM>. The media is shown in a wound configuration with the media separated from one another by having filter media <NUM> laid down first, and then second media <NUM> laid down on top of media <NUM>, and third media <NUM> is laid down on top of media <NUM>. In this example embodiment the ratio of pack entrance area <NUM> to <NUM> to <NUM> is approximately <NUM>:<NUM>:<NUM>.

<FIG> is a top schematic view of an example filter media pack <NUM>, showing a wound configuration with three types of filter media. The filter media pack <NUM> has first media <NUM>, second media <NUM> and third media <NUM>. The media is shown in wound configuration with the three types of media separated from one another. In this example embodiment the ratio of pack entrance area. <NUM> to <NUM> to <NUM> is approximately <NUM>:<NUM>:<NUM>.

<FIG> is a top schematic view of an example filter media pack <NUM>, showing a wound configuration with two types of filter media. The filter media pack <NUM> has two types of filter media: first media <NUM>, and second media <NUM>. The media is shown in a wound configuration with the two types of media separate on one another by having filter media <NUM> laid down first, and then filter media <NUM> laid down on top of media <NUM>. In this example embodiment the ratio of pack entrance area. <NUM> to <NUM> is approximately <NUM>:<NUM>.

<FIG> is a top schematic view of an example filter media pack <NUM>, showing a wound configuration with two types of filter media. The filter media pack <NUM> has two types of filter media: first media <NUM>, and second media <NUM>. The media is shown in wound configuration with the two types of media separated from one another. In this example embodiment the ratio of pack entrance area. <NUM> to <NUM> is approximately <NUM>:<NUM>.

Aspects may be better understood with reference to the following example, in which Element A, Element B, and Element C were compared to one another. Element A was composed entirely of Media A with flutes having a width of approximately <NUM> millimeters and height of <NUM> millimeters and a tapered cross-sectional area. Element B was composed entirely of Media B with flutes having a width of approximately <NUM> millimeters and a height of approximately <NUM> millimeters and a tapered area. The flute density per square centimeter was approximately <NUM> for Element A and <NUM> for Element B. Element C was composed of <NUM> percent by volume with Media A, and <NUM> percent by volume of Media B to form a Hybrid Media. <FIG> shows a loading curve for filter elements made using Media A, Media B, and the Hybrid Media. The loading curve shows the pressure loss of the filter elements as the grams of dust increases from zero to up to less than <NUM> grams. As shown in <FIG>, Media B and the hybrid media started with very similar restriction levels (approximately <NUM> inches of H<NUM><NUM>), while Media A had a higher initial pressure loss, which is approximately <NUM> inches of H<NUM><NUM>. As dust begins to load the pressure loss across all elements increases, however Media A and the Hybrid Media have a slower increase in pressure loss than Media B, with the pressure loss of Media A and Media B crossing (or being the same) at about <NUM> grams of dust. Thus, the Hybrid Media tracked closely with Media B when dust loading was just starting, and then tracked closely with Media A as the dust loading increased to higher levels. In other words, the hybrid media had initial restriction similar to Media B, but loading similar to Media A.

In order to further test improved filter performance, a test bench was set up with a two-duct system having <NUM> to <NUM> cubic meters per minute of air flow, configured to measure pressure loss, as well as outlet restriction values. Relative performance of media elements formed using combinations of filter medias was investigated by constructing various filter element designs. The elements were formed with z-flow media arranged in a stacked configuration. The elements each had a <NUM> by <NUM> millimeter inlet face and a <NUM> by <NUM> millimeter outlet face and were <NUM> millimeters deep. Filter elements were made with two types of media: Media A and Media B. Media A and Media B had media flute constructions consistent with those shown in <CIT>, entitled Filtration Media Pack, Filter Elements, and Air Filtration Media to inventor Scott M. Brown and assigned to Donaldson Company, Inc. Media A and B were both primarily cellulosic media. Media A had a flute height of about <NUM> inch, flute width of about <NUM> inch, and flute length of about <NUM> millimeters (including flute plugs). Media B had a flute height of about <NUM> inch, flute width of about <NUM> inch, and flute length of about <NUM> millimeters (including flute plugs). A first type of "segmented" media pack was assembled packs of Media A and Media B located next to one another in parallel flow. A second type of "layered" media pack included alternating sheets of Media A and Media B.

<FIG> show performance results, including dust loading and pressure loss, for various media constructions. <FIG>, <FIG> and <FIG> show results for a segmented configuration (Media A was grouped together and all of Media B was grouped together); and <FIG>, <FIG>, and <FIG> show results for a layered configuration (in which at least some of the Media A and Media layers were intermixed). Thus, the media constructions include either Media A, Media B, or various percentages by volume of Media A and Media B. Media on the far left of each graph, denoted as <NUM>%, has no Media A and is thus entirely Media B. Media on the far right, denoted as <NUM>%, have only Media A and thus no Media B. The Y axis contains both ISO fine dust loading measured in grams, as well as pressure loss measured in inches of water.

<FIG> shows performance results, including dust loading and pressure loss, for various media constructions at a cube flow rate of <NUM> cubic meters per minute. From <FIG> it will be observed that the best performance, specifically the highest dust loading, was achieved with a hybrid media: the hybrid media pack containing both Media A and Media B had higher dust loading capacity than either Media A or Media B alone.

<FIG> show performance results, including dust loading and pressure loss, for various media constructions at a cube flow rate of <NUM> cubic meters per minute. Again, as with <FIG>, the best performance was with a hybrid media of both Media A and Media B.

<FIG> show performance results, including dust loading and pressure loss, for various media constructions at a cube flow rate of <NUM> cubic meters per minute. From <FIG> it will be observed that the best performance, specifically the highest dust loading, was again achieved with a hybrid media.

It should be noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. Thus, for example, reference to a composition containing "a compound" includes a mixture of two or more compounds. It should also be noted that the term "or" is generally employed in its sense including "and/or" unless the content clearly dictates otherwise.

Claim 1:
An air filtration media pack (<NUM>, <NUM>, <NUM>, <NUM>) comprising:
a plurality of layers of fluted single facer media (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>), the single face media (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) includes a fluted sheet (<NUM>) and a bottom facer sheet (<NUM>),
a first plurality of flutes (<NUM>) arranged in the fluted sheet (<NUM>) of a first plurality of layers of fluted single facer media (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) forming a first media section, and a second plurality of flutes (<NUM>) arranged in the fluted sheet (<NUM>) of a second plurality of layers of fluted single facer media (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) forming a second media section, the first and second plurality of flutes (<NUM>) being arranged in a parallel flow configuration, wherein a fluid stream to be filtered diverges into the first and second plurality of flutes, and then converges again later,
the first plurality of flutes and second plurality of flutes extending from a first face to a second face of the filtration media pack, a first portion of the first and second plurality of flutes are closed to unfiltered air flowing into the first portion of the first and second plurality of flutes, and a second portion of the first and second plurality of flutes are closed to unfiltered air from flowing out of the second portion of the first and second plurality of flutes, wherein air passing into flutes on one face of the media pack passes through filter media before flowing out flutes on the other face of the media pack; and
wherein the first plurality of flutes and second plurality of flutes exhibit differences in flute shape, flute size, flute height, flute width, cross-flute area, or filter media such that the two media sections have distinct pressure loss and loading properties, the difference being at least <NUM> percent, and
wherein the first and second plurality of layers of fluted single facer media are arranged in an intermixed configuration with one or more layers of the first plurality of fluted single facer media alternating with one or more layers of the second plurality of fluted single facer media.