Patent Description:
Known filter elements are for example disclosed in <CIT>, <CIT>, <CIT>, <CIT> and <CIT>. Air intake for gas turbines, and other such systems, require filtration of the air so that particulates in the air do not damage downstream components, such as the turbine. As such, the filters used are important, and having the proper filter element installed is important in protecting the downstream turbine. Improvements in such filter systems are desirable.

A filter element and filter assembly are provided that improve the prior art.

The claimed invention is defined in independent claims <NUM> and <NUM>.

The claimed invention relates to a filter element as defined in independent claim <NUM>.

The claimed invention also relates to a filter assembly as defined in independent claim <NUM>.

Preferred configurations of the claimed filter element are defined in dependent claims <NUM>-<NUM>.

Preferred configurations of the claimed filter assembly are defined in dependent claims <NUM> and <NUM>.

The filter element of independent claim <NUM> comprises (a) a tubular section of filter media; and (b) a first end cap secured to the filter media; (i) the first end cap having a seal arrangement along an inner radial surface; (ii) the seal arrangement including a seal member having an inwardly radially directed seal surface and a thickness that varies along the seal member surface, the thickness of the seal member surface varying in a radial direction along the seal member surface; wherein the radially directed seal surface comprises a plurality of outwardly projecting and axially extending portions and a plurality of inwardly projecting and axially extending portions and (c) a second end cap secured to the filter media opposite of the first end cap; (i) the second end cap being closed except for a seal-receiving opening in the center of the second end cap; the seal-receiving opening having an outer diameter less than <NUM>% of an outer diameter of the second end cap.

In embodiments, a length of the seal member surface is constant in an axial direction.

In some embodiments, the seal member thickness varies by a minimum thickness and a maximum thickness, wherein the maximum thickness is at least <NUM> times the minimum thickness.

In some embodiments, the plurality of outwardly projecting and axially extending portions and the plurality of inwardly projecting and axially extending portions comprise curved portions.

In embodiments, the filter media is pleated media.

In embodiments, the tubular section of filter media has a round cross-section.

The filter assembly of claim <NUM> comprises (a) a tube sheet having a filtered air aperture; (b) a tube sheet seal member along the aperture; the seal member having a plurality of alternating outward radial portions and alternating inward radial portions; and (c) a filter element of any one of claims <NUM>-<NUM> releasably secured to the tube sheet; wherein (i) the tubular section of filter media defining an interior volume in communication with the filtered air aperture; and (ii) the seal member forming a seal with the tube sheet seal member in that: (A) the tube sheet seal member inward radial portions receive the outwardly projecting and axially extending portions of the seal member; and (B) the inwardly projecting and axially extending portions of the seal member receive the tube sheet seal member outward radial portions.

In some embodiments, the tube sheet seal member is part of a seal plate having a collar and a neck, the collar being attachable to the tube sheet, and the neck projecting axially from the collar, the tube sheet seal member being along the neck.

The filter assembly may further comprise a yoke plate secured to the tube sheet, the yoke plate including a fixture holding a rod removably securing the filter element to the tube sheet.

In some embodiments, the second end cap is an open end cap.

In embodiments where the second end cap is an open end cap, the second end cap includes a second filter element seal member having a plurality of compressible alternating radial projections and alternating radially recesses.

In embodiments that have a second open end cap, the filter assembly can further include an assembly cover having a plurality of alternating outward radial portions and alternating inward radially portions. The assembly cover may be received within and form a seal with the second end cap such that the assembly cover inward radial portions receive the second filter element seal member radial projections; and the second filter element seal member radial recesses receive the assembly cover outward radial portions.

In embodiments that include an assembly cover, the filter assembly can further include a gasket washer and a pivotable handle, wherein the rod extends through the assembly cover and is secured to the gasket washer and handle to removably secure the filter element to the tube sheet.

In some embodiments, the filter element is one in a filter pair; the filter pair comprising either two cylindrical elements, or a conical element and a cylindrical element stacked axially.

In some embodiments that include a second open end cap, the assembly further includes an additional filter cartridge removably mounted within the second end cap. The additional filter cartridge has a media pack comprising opposite first end and second flow faces with flutes extending in a direction therebetween and a sidewall extending between the first and second flow faces. At least some of the flutes have an upstream portion adjacent the first flow face that are open and a downstream portion adjacent the second flow face that are closed. At least some of the flutes have an upstream portion adjacent the first flow face that are closed and a downstream portion adjacent the second flowface that are open. A band is around the sidewall of the additional filter cartridge. The band includes a plurality of alternating outward radial portions and alternating inward radial portions. The additional filter cartridge is received within and forms a seal with the second end cap such that the band inward radial portions receive the second filter element seal member radial projections; and the second filter element seal member radial recesses receive the band outward radial portions.

In embodiments that include an additional filter cartridge, the filter assembly may further include a gasket washer and a pivotable handle, wherein the rod extends through the additional filter cartridge and is secured to the gasket washer and handle to removably secure the filter element to the tube sheet.

A variety of examples of desirable product features or methods are set forth in the description that follows, and in part, will be apparent from the description, or may be learned by practicing various aspects of this disclosure. The aspects of this disclosure may relate to individual features, as well as combinations of features. It is to be understood that both the foregoing general description and the following detailed description are explanatory only, and are not restrictive of the claimed inventions.

<FIG> and <FIG> depict two types of example gas turbine air intake systems (filter systems) at <NUM>. The system of <FIG> includes filter elements that are horizontally oriented, while the system of <FIG> includes filter elements that are vertically oriented. Common parts will use the same reference number.

In <FIG>, the system <NUM> includes a chamber <NUM> having an air inlet side <NUM> and an air outlet side <NUM>. Air enters the chamber <NUM> through a plurality of vertically spaced inlet hoods <NUM> positioned along the air inlet side <NUM>. The inlet hoods <NUM>, although not required, function to protect internal filters of the system <NUM> from the effects of rain, snow and sun. Also, the inlet hoods <NUM> are configured such that air entering the inlet hoods <NUM> is first directed in an upward direction indicated by arrow <NUM>, and then deflected by deflector plates <NUM> in a downward direction indicated by arrow <NUM>. The initial upward movement of air causes some particulate material and moisture from the air stream to settle or accumulate on lower regions <NUM> of the inlet hoods <NUM>. The subsequent downward movement of air forces dust within the chamber <NUM> downward toward a dust collection hopper <NUM> located at the bottom of the chamber <NUM>. It should also be noted that air inlet side <NUM> may have vanes and other mechanical moisture separator inlets.

The chamber <NUM> of the system <NUM> is divided into upstream and downstream volumes <NUM> and <NUM> by a tube sheet <NUM> (also referred to also as partition <NUM>), which is oriented vertically in the <FIG> embodiment and horizontally in the <FIG> embodiment. The upstream volume <NUM> generally represents the "dirty air section" of the air cleaner system <NUM>, while the downstream volume <NUM> generally represents the "clean air section" of the system <NUM>. The tube sheet <NUM> defines a plurality of apertures <NUM> for allowing air to flow from the upstream volume <NUM> to the downstream volume <NUM>. Each aperture <NUM> is covered by a filter pair <NUM>, comprising a cylindrical element <NUM> and a conical element <NUM>. In other embodiments, the filter pair <NUM> can include two cylindrical elements; or alternatively, instead of a filter pair <NUM>, there may be only a single element such as cylindrical element <NUM>. In <FIG>, the conical air filter element <NUM>, covers the aperture <NUM>. Both elements <NUM> and <NUM> are located in the upstream volume <NUM> of the chamber. The filter elements <NUM>, <NUM> are arranged and configured such that air flowing from the upstream volume <NUM> to the downstream volume <NUM> passes through the filter elements <NUM>, <NUM> prior to passing through the apertures <NUM>.

In general, during filtering, air is directed from the upstream volume <NUM> through the filter elements <NUM>. After being filtered, the air flows through the tube sheet <NUM>, via apertures <NUM>, into the downstream clean air volume <NUM>. The clean air is then drawn out from the downstream volume <NUM> and into a gas turbine intake, not shown. The elements <NUM>, in the system <NUM> of <FIG>, may be pulse cleaned to direct pulses of air backward through the interior of the element <NUM> to dislodge material on an upstream portion of the elements <NUM>. The pulse jet air cleaners can be sequentially operated from the top to the bottom of the chamber <NUM> to eventually direct the dust particulate material blown from the filters into the lower hopper <NUM>, for removal. In many air pulse jet cleaning applications, a useful air pressure is generally within the range of <NUM> to <NUM> psi, wherein <NUM> psi equals <NUM>,<NUM> bar.

In the <FIG> embodiment, the tube sheet <NUM> is horizontal. In the system <NUM> of <FIG>, each aperture <NUM> of the tube sheet <NUM> includes a venturi tube <NUM> for directing a pulse jet air of air mounted in the downstream volume <NUM>. Periodically, a pulse jet air cleaner is operated to direct a pulse jet of air backwardly through the venturi tube <NUM> and into the interior of the associated air filter element <NUM> to dislodge particular material trapped in or on the air filter element <NUM>. The air to be filtered flows upwardly at inlet side <NUM>, then through the elements <NUM>, and then through the venturis <NUM>, into the downstream volume <NUM>, and exits through the outlet <NUM>.

<FIG> is a perspective view of a filter assembly <NUM>, which can be used in the system <NUM> of <FIG>. <FIG> shows a cross-sectional view of filter assembly <NUM>, when filter pair <NUM> is used in the system of <FIG>. The filter assembly <NUM> can have many different embodiments. One example embodiment is in <FIG> and <FIG>; while another example embodiment is in <FIG> and <FIG>; another example embodiment shown in <FIG>; another example embodiment shown in <FIG>; and another example embodiment is in <FIG>. These filter assemblies <NUM> have common components, and the same reference numerals will be used to show the same components (except for the embodiment of <FIG>, which uses different reference numerals).

In <FIG>, the filter element <NUM> can be seen operably installed adjacent the tube sheet <NUM>. As will be explained further below, the element <NUM> is sealed to seal plate <NUM>, which is against the tube sheet <NUM>. Also visible in <FIG> is a pivotable handle <NUM>, which is part of a yoke assembly to removably secure the filter element <NUM> to the tube sheet <NUM>. The handle <NUM> can be similar to the handle as described in <CIT> and <CIT>.

In the embodiments of <FIG>, <FIG>, and <FIG>, the aperture <NUM> (<FIG>) in the tube sheet <NUM> includes a tube sheet seal member <NUM>. The tube sheet seal member <NUM> is along the aperture <NUM> and is attached to the tube sheet <NUM>. It is releasably sealed to the filter element <NUM>, as described further below. Many examples are possible, and in the example embodiments of <FIG>, <FIG>, and <FIG>, the tube sheet seal member <NUM> is part of seal plate <NUM>. The seal plate <NUM> is described further below and is used to attach the tube sheet seal member <NUM> to the tube sheet <NUM>.

Also visible in <FIG> and <FIG> is a rod <NUM> which can be held by a fixture <NUM>, which is part of the yoke assembly for releasably holding the filter element <NUM> to the tube sheet <NUM>. <FIG> includes a tri-pod of legs <NUM>, which is part of the yoke assembly for releasably holding the filter pair <NUM> to the tube sheet <NUM>.

One difference between the assemblies <NUM> of <FIG>, <FIG> and <FIG> is the assembly at the end of the filter element <NUM> opposite of the end that connects to the tube sheet <NUM>. In the <FIG> and <FIG> assemblies, there is an assembly cover <NUM>. The assembly cover <NUM>, which is described further below, covers the end of the filter element <NUM> and receives the rod <NUM> (<FIG>) or tri-pod legs <NUM> (<FIG>) to allow the yoke assembly including the handle <NUM> to releasably secure the filter element <NUM> (<FIG>) or filter pair <NUM> (<FIG>) to the tube sheet <NUM>. As can also be seen in <FIG>, there is a gasket washer <NUM>, which engages the handle <NUM> and helps to releasably lock the filter element <NUM> to the tube sheet <NUM>.

In the <FIG> embodiment, instead of an assembly cover <NUM>, there is a second or an additional filter cartridge <NUM>. The additional filter cartridge <NUM> covers the open end of the filter element <NUM>, which is opposite of the tube sheet <NUM>, and provides for additional filtration. This is described further below. The additional filter cartridge <NUM> allows for the rod <NUM> to pass therethrough and engage the handle <NUM> and gasket washer <NUM>.

An example embodiment of filter element <NUM> is now described further. The filter element <NUM> includes a tubular section of filter media <NUM>. The tubular section of media <NUM>, in this embodiment, is cylindrical and has a round cross-section. In other embodiments, the tubular shape could be non-cylindrical and have an oval or elliptical cross-section.

In this embodiment, the media <NUM> is pleated media <NUM>. The pleated media <NUM> can be made from cellulous. Many alternatives are possible.

The filter element <NUM> further includes a first end cap <NUM> and an opposite second end cap <NUM>. The filter media <NUM> is secured to and extends between the first end cap <NUM> and second end cap <NUM>.

The first end cap <NUM> is an open end cap in that it has an opening <NUM> in communication with an interior volume <NUM> defined by the tubular section of media <NUM>.

While in some embodiments, the second end cap <NUM> could be a closed end cap, in the embodiment depicted, the second end cap <NUM> is an open end cap defining an opening <NUM>. The opening <NUM> is in communication with the interior volume <NUM>. Further details about the first end cap <NUM> and second end cap <NUM> are discussed below.

An inner liner <NUM> extends between the first end cap <NUM> and second end cap <NUM>. As will be described further below, the inner liner <NUM> helps prevent the pleats of the pleated media <NUM> from collapsing and acts as a seal support. In alternate embodiments, no seal support is used, and in some of those alternate embodiments, no inner liner is used so that the element is inner-liner free.

In this embodiment, there is also an optional outer liner <NUM>. The outer liner <NUM> is radially outside of the outer pleat tips of the pleated media <NUM> and extends between the first end cap <NUM> and second end cap <NUM>. The outer liner <NUM> can also help support the pleats. In alternative embodiments, there is no outer liner at all.

In <FIG>, it can be seen how, in this embodiment, there is an optional winding bead <NUM> around the exterior of the pleated media <NUM>. The winding bead <NUM> can include, for example, tape or a hot melt adhesive. The winding bead <NUM> will help to support the pleats and prevent pleat collapse.

In reference now to <FIG> and <FIG>, the first and second end caps <NUM>, <NUM> are further discussed. In the <FIG> embodiment, the conical element is illustrated as having first end cap <NUM>' and second end cap <NUM>'. Because these end caps <NUM>', <NUM>' are used with the conically shaped element <NUM>, they vary in proportion to the end caps <NUM>, <NUM>. It should be understood, however, that the description of the end caps <NUM>, <NUM> generally applies to the end caps <NUM>', <NUM>' with the exception that the end caps <NUM>', <NUM>' are not identical to each other, and will vary in proportions. The end caps <NUM>', <NUM>' will form seals in the same general way as the end caps <NUM>, <NUM>, as described next.

Each of the first end cap <NUM> and second end cap <NUM> has a seal arrangement <NUM>, <NUM> along an inner radial surface <NUM>, <NUM> of each of the end caps <NUM>, <NUM>. While many variations are possible, in the preferred embodiment shown, the seal arrangements <NUM>, <NUM> are identical in that they have a same shape as the other. In this way, the filter element <NUM> can be installed in the system <NUM> in any orientation. That is, in this embodiment, it does not matter whether the first end cap <NUM> or the second end cap <NUM> is in connection with the tube sheet <NUM>. (As noted above, this is not the case for the conical element <NUM>, in which the end cap <NUM>' is the only end that connects to the tube sheet <NUM>. ) Both the first end cap <NUM> and second end cap <NUM> are attachable to the tube sheet <NUM>. Likewise, at the end opposite of the tube sheet <NUM>, either one of the first end cap <NUM> or second end cap <NUM> is attachable to the other components including, for example, the assembly cover <NUM> (<FIG> and <FIG>) or the additional filter cartridge <NUM> (<FIG>). In <FIG>, the element <NUM> has end caps <NUM>, <NUM> which are both attachable to assembly cover <NUM> or to the conical element <NUM>.

Because in this embodiment the seal arrangements <NUM>, <NUM> are identical, the same reference numerals and description will be used for each. It should be understood that in other arrangements, only one of the end caps would have the seal arrangement, while the opposite end cap could be a closed end cap or have a different configuration.

The seal arrangements <NUM>, <NUM> include seal support, in the form of inner liner <NUM>, and a seal member <NUM> supported by the seal support <NUM>. The seal member <NUM> has an inwardly radially directed seal surface <NUM> and a thickness between the seal support <NUM> and the seal member surface <NUM> that varies along the seal member surface <NUM>. The thickness of the seal member <NUM> can also be measured from the inner pleat tips of the pleated media <NUM>. Example useable seal arrangements are described in <CIT>.

As can be appreciated by reviewing <FIG>, the thickness between the seal support <NUM> (or the inner pleat tips of the pleated media <NUM>) and the seal member <NUM> varies in a radial direction along the seal member surface <NUM>. The thickness between the seal support <NUM> and the seal member surface <NUM> is constant in an axial direction. In other words, the length of the seal member surface <NUM> along the seal support <NUM> is relatively constant in the axial direction, i.e., the direction generally parallel to the inner liner <NUM>.

While many variations are possible, the seal member thickness varies by a minimum thickness and a maximum thickness. In general, the maximum thickness is at least <NUM> times the minimum thickness. Many variations are possible. In embodiments in which the seal support is omitted, the thickness of the seal member <NUM> is measured from the inner pleat tips of the pleated media <NUM>.

The seal arrangements <NUM>, <NUM> can be designed in accordance with the description of the seal arrangements provided in Patent Publication No. <CIT>.

In general, the radially directed seal surface <NUM> includes a plurality of outwardly projecting and axially extending portions <NUM> and a plurality of inwardly projecting and axially extending portions <NUM>. While many embodiments are possible, the plurality of outwardly projecting and axially extending portions <NUM> and the plurality of inwardly projecting and axially extending portions <NUM> comprise curved portions.

While many embodiments are possible, in the one shown, the plurality of outwardly projecting and axially extending portions <NUM> alternate with the plurality of inwardly projecting and axially extending portions <NUM>. As such, the seal member <NUM> forms a plurality of compressible alternating radial projections <NUM> and alternating radial recesses <NUM>.

There can be only a few or many portions <NUM>, <NUM>. For example, the radially directed seal surface <NUM> may comprise at least two of the radially outwardly projecting and axially extending portions <NUM> alternating with at least two of the radially inwardly projecting and axially extending portions <NUM> per inch along the seal support <NUM> extending around a central axis <NUM> of the filter element <NUM>. In many instances, radially directed seal surface <NUM> comprises greater than <NUM> of the radially outwardly projecting and axially extending portions <NUM> alternating with greater than <NUM> of the radially inwardly projecting and axially extending portions <NUM>.

In an alternative embodiment, the second end cap <NUM> is closed with the exception of a small opening in the center, which receives a non-removable or a removable seal. The first end cap <NUM> includes seal arrangement <NUM>. The small opening in the center can have a diameter less than <NUM>% of the outer diameter of the second end cap. In some embodiments, the small opening in the center can receive a sealing washer around a shaft, used for retention, in which the seal is formed between the shaft and the hole. Alternatively, the seal could be molded into the hole.

Attention is directed to <FIG> and <FIG>, which show an example embodiment of how the filter element <NUM> is releasably attached to the tube sheet <NUM>. As previously mentioned, the assembly <NUM> includes seal plate <NUM>. Further views of the seal plate <NUM> are shown in <FIG>.

The seal plate <NUM> includes the tube sheet seal member <NUM> the tube sheet seal member <NUM> defines an inner opening <NUM> therethrough. The opening <NUM> is in communication with the aperture <NUM> in the tube sheet <NUM>, when the seal plate <NUM> is operably mounted to the tube sheet <NUM>.

In this embodiment, the seal plate <NUM> includes a collar <NUM> and a neck <NUM>. The collar <NUM> includes an outer rim <NUM> which is against and adjacent the tube sheet <NUM>. The collar <NUM>, in this embodiment, extends generally along the tube sheet <NUM> and can be generally parallel to the tube sheet <NUM>, although variations are possible.

The neck <NUM> projects axially from the collar <NUM> and circumscribes the opening <NUM>. The tube sheet seal member <NUM> is generally along and can be part of the neck <NUM>. The neck <NUM> extends in an axial direction opposite of the direction that the rim <NUM> extends from the collar <NUM>.

The tube sheet seal member <NUM> is shaped to releasably seal with the seal arrangements <NUM>, <NUM>. In this embodiment, the tube sheet seal member <NUM> has a plurality of alternating outward radial portions <NUM> and alternating inward radial portions <NUM>. As can be seen in <FIG>, there are greater than <NUM> outward radial portions <NUM> and inward radial portions <NUM>. The outward radial portions <NUM> and inward radial portions <NUM>, in this embodiment, extend substantially a complete length of the neck <NUM>.

When the filter element <NUM> is removably attached to the tube sheet <NUM>, the seal member <NUM> forms a seal with the tube sheet seal member <NUM> in that the tube sheet seal member <NUM> inward radial portions <NUM> receive the first filter element seal member radial projections <NUM>; and the seal member <NUM> having the radial recesses <NUM> receive the tube sheet seal member <NUM> outward radial portions <NUM>. This connection helps to ensure a good seal is formed, and ensure that the correct filter element <NUM> is being installed within the filter assembly <NUM>.

In reference again to <FIG> and <FIG>, the filter assembly <NUM> includes a yoke plate <NUM>. Additional views of the yoke plate <NUM> can be seen in <FIG>. The yoke plate <NUM> is secured to the tube sheet on the clean side of the tube sheet <NUM>, on an opposite side from where the filter element <NUM> is secured. <FIG> omits the presence of the tube sheet from the drawing, to enhance clarity.

The yoke plate <NUM> defines an opening <NUM>, which is generally coaxially aligned with the aperture <NUM> in the tube sheet <NUM> and opening <NUM> in the seal plate <NUM>.

The yoke plate <NUM> includes a surrounding band <NUM>, surrounding the opening <NUM>. The band <NUM> generally lies flat and against the tube sheet <NUM>, although variations are possible.

The band <NUM> can include a plurality of holes <NUM>. The holes <NUM> accommodate fasteners, such as bolts <NUM>. The bolts <NUM> extend through a portion of the venturi tube <NUM> and secure the venturi tube <NUM> to the tube sheet <NUM>.

The yoke plate <NUM> includes a chord extending across the opening <NUM> between edges of the band <NUM>. In this example, the chord <NUM> extends across the geometric center of the opening <NUM>, although there could be variations in other embodiments. The chord <NUM> includes the fixture <NUM> for removably holding the rod <NUM>. As can be seen in <FIG>, there is a gasket washer <NUM>, which is part of the fixture <NUM>, for holding the rod <NUM>.

The rod <NUM> is secured to the tube sheet <NUM> with the gasket washer <NUM> and the yoke plate <NUM>. The rod <NUM> extends through the interior volume <NUM> of the filter element <NUM> and through either the assembly cover <NUM> or the additional filter cartridge <NUM>, depending upon the embodiment.

The end of the rod <NUM> includes radial projections <NUM>, <NUM> (<FIG> and <FIG>). The radially projections <NUM>, <NUM> engage with the handle <NUM>, such that when the handle <NUM> is pivoted in the locked position (<FIG>), with the grasping portion <NUM> (<FIG>) pointing generally radially outwardly, the filter element <NUM> is sealed to the tube sheet seal member <NUM> through a radial seal. When the handle <NUM> is in a released position with the grasping portion <NUM> pointing generally in an axial direction, the projections <NUM>, <NUM> on the rod <NUM> are not tightly engaged with the handle <NUM>, and the filter element <NUM> can be removed from the tube sheet seal member <NUM> and the tube sheet <NUM> by removing the handle <NUM> and removing the gasket washer <NUM>.

In the <FIG>, embodiment, the cylindrical element <NUM> and conical element <NUM> are sealed together along connection <NUM> piece. The connection piece <NUM> can be shaped to be received by and form seals with end cap <NUM>' and end cap <NUM>; alternatively, the connection piece <NUM> can form an axial insert between elements <NUM> and <NUM> to form an axial seal therebetween.

As mentioned previously, in the embodiment of <FIG> and <FIG>, the filter assembly <NUM> includes assembly cover <NUM>. Further views of the assembly cover <NUM> are shown in <FIG> and <FIG>.

Referring now to <FIG> and <FIG>, the assembly cover <NUM> includes a surrounding wall <NUM>. The wall <NUM> extends from an end plate <NUM>. In general, the wall <NUM> is perpendicular to the end plate <NUM>. The wall <NUM> is sized to extend into the opening <NUM> of the second end cap <NUM> (or alternatively, into the opening <NUM> of the first end cap <NUM>, when the filter element <NUM> is axially reversed).

The end plate <NUM> is sized to extend over and cover the axial end of the second end cap <NUM> (or the first end cap <NUM>, when the element <NUM> is reversed).

The end plate <NUM> includes an aperture <NUM> in the center therethrough. The aperture <NUM> allows for passage of the rod <NUM>.

In <FIG>, it can be seen how the end plate <NUM> includes an outer most brim <NUM>, which is generally planar and flat. The surrounding wall <NUM> extends from an inside surface <NUM> of the brim <NUM>.

Extending radially inwardly along the brim <NUM> and radially inwardly of where the wall <NUM> extends, the end plate <NUM> includes a concave section <NUM>. The concave section <NUM> extends inwardly to be within the surrounding wall <NUM>. In the center of the concave section <NUM> is the aperture <NUM>. Many embodiments are possible.

The assembly cover <NUM> includes a plurality alternating outward radial portions <NUM> and alternating inward radial portions <NUM>. In the embodiment shown, the outward radial portions <NUM> and inward radial portions <NUM> are part of the surrounding wall <NUM>. As such, the assembly cover <NUM> can be used to form a seal with the second end cap <NUM> (alternatively, with the first end cap <NUM>). A releasable seal can be formed between the element <NUM> and assembly cover <NUM> by having the inward radial portions <NUM> of the assembly cover <NUM> receive the seal member radial projections <NUM>; and the seal member radial recesses <NUM> receive the outward radial portions <NUM> of the assembly cover <NUM>.

As mentioned previously, in the embodiment of <FIG>, the assembly <NUM> includes additional filter cartridge <NUM>. Additional views of the additional filter cartridge <NUM> are depicted in <FIG> and <FIG>. Alternative embodiments are shown in <FIG> and <FIG>.

The additional filter cartridge <NUM> is made from z-filter media <NUM>. The filter media <NUM> can be used to form a "z-filter construction. " The term "z-filter construction" as used herein, is meant to include (but not be limited) a type of filter construction in which individual ones of corrugated, folded or otherwise formed filter flutes are used to define (typically in combination with facing media) sets of longitudinal, typically parallel, inlet and outlet filter flutes for fluid flow through the media. Some examples of z-filter media are provided in <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; Des. <NUM>,<NUM>; Des. <NUM>,<NUM>; Des. <NUM>,<NUM>; Des. <NUM>,<NUM>; and, Des. <NUM>,<NUM>.

One type of z-filter media, utilizes two specific media components joined together, to form the media construction. The two components are: (<NUM>) a fluted (typically corrugated) media sheet or sheet section, and, (<NUM>) a facing media sheet or sheet section. The facing media sheet is typically non-corrugated, however it can be corrugated, for example perpendicularly to the flute direction as described in <CIT>, and published as <CIT>.

The fluted media section and facing media section can comprise separate materials between one another. However, they can also be sections of the single media sheet folded to bring the facing media material into appropriate juxtaposition with the fluted media portion of the media.

The fluted (typically corrugated) media sheet and the facing media sheet or sheet section together, are typically used to define media having parallel flutes. In some instances, the fluted sheet and facing sheet are separate and then secured together and are then coiled, as a media strip, to form a z-filter media construction. Such arrangements are described, for example, in <CIT> and <CIT>. In certain other arrangements, some non-coiled sections or strips of fluted (typically corrugated) media secured to facing media, are stacked with one another, to create a filter construction. An example of this is described in <FIG> of <CIT>.

Herein, strips of material comprising fluted sheet (sheet of media with ridges) secured to corrugated sheet, which are then assembled into stacks to form media packs, are sometimes referred to as "single facer strips," "single faced strips," or as "single facer" or "single faced" media. The terms and variants thereof, are meant to refer to a fact that one face, i.e., a single face, of the fluted (typically corrugated) sheet is faced by the facing sheet, in each strip.

Typically, coiling of a strip of the fluted sheet/facing sheet (i.e., single facer) combination around itself, to create a coiled media pack, is conducted with the facing sheet directed outwardly. Some techniques for coiling are described in <CIT> and <CIT>, now published as <CIT>. 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 often used 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 corrugations in the resulting media. The term "corrugation" is however, not meant to be limited to such flutes, unless it is stated that they result from flutes that are by techniques involving passage of media into a bite between corrugation rollers. 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 <CIT>.

Corrugated media is a specific form of fluted media. Fluted media is media which has individual flutes or ridges (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 or cartridges 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 "serviceable" in this context is meant to refer to a media containing filter cartridge that is periodically removed and replaced from a corresponding fluid (e.g. air) cleaner. In some instances, each of the inlet flow end (or face) and outlet flow end (or face) 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 or stacked media pack) is, for example, in contrast to serviceable filter cartridges such as cylindrical pleated filter cartridges of the type shown in <CIT>, in which the flow generally makes a substantial turn as its passes into and out of the media. That is, in a <NUM>,<NUM>,<NUM> filter, the flow enters the cylindrical filter cartridge through a cylindrical side, and then turns to exit through an open end of the media (in forward-flow systems). In a typical reverse-flow system, the flow enters the serviceable cylindrical cartridge through an open end of the media and then turns to exit through a side of the cylindrical filter media. An example of such a reverse-flow system is shown in <CIT>.

The term "z-filter media construction" and variants thereof as used herein, without more, is meant to include, but not necessarily be limited to, any or all of: a web of corrugated or otherwise fluted media (media having media ridges) secured to (facing) media, whether the sheets are separate or part of a single web, with appropriate sealing (closure) to allow for definition of inlet and outlet flutes; and/or a media pack constructed or formed from such media into a three dimensional network of inlet and outlet flutes; and/or, a filter cartridge or construction including such a media pack.

In <FIG>, an example of media <NUM> useable in z-filter media is shown. The media <NUM> is formed from a corrugated (fluted) sheet <NUM> and a facing sheet <NUM>.

In general, the corrugated sheet <NUM>, <FIG>, is of a type generally characterized herein as having a regular, curved, wave pattern of flutes or corrugations <NUM>. The term "wave pattern" in this context, is meant to refer to a flute or corrugated pattern of alternating troughs 407b and ridges 407a. The term "regular" in this context is meant to refer to the fact that the pairs of troughs and ridges (407b, 407a) alternate with generally the same repeating corrugation (or flute) shape and size. Also, typically in a regular configuration each trough 407b is substantially an inverse of each ridge 407a. 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 <NUM>% 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 <NUM> 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 <NUM> 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> the media <NUM> depicted in fragmentary has eight complete ridges 407a and seven complete troughs 407b. 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 407a of each ridge and the bottom 407b 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 <NUM> and typically would be not more than <NUM>. 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>, for the corrugated sheet <NUM>, is that at approximately a midpoint <NUM> between each trough and each adjacent ridge, along most of the length of the flutes <NUM>, is located a transition region where the curvature inverts. For example, viewing back side or face 403a, <FIG>, trough 407b is a concave region, and ridge 407a is a convex region. Of course when viewed toward front side or face 403b, trough 407b of side 403a forms a ridge; and, ridge 407a of face 403a, forms a trough. In some instances, region <NUM> can be a straight segment, instead of a point, with curvature inverting at ends of the straight segment <NUM>.

A characteristic of the particular regular, curved, wave pattern corrugated sheet <NUM> shown in <FIG>, is that the individual corrugations are generally straight. By "straight" in this context, it is meant that through at least <NUM>% (typically at least <NUM>%) of the length between edges <NUM> and <NUM>, the ridges 407a and troughs 407b do not change substantially in cross-section. The term "straight" in reference to corrugation pattern shown in <FIG>, in part distinguishes the pattern from the tapered flutes of corrugated media described in <FIG> of <CIT> and <CIT>. The tapered flutes of <FIG> of <CIT>, 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> and as referenced above, the media <NUM> has first and second opposite edges <NUM> and <NUM>. When the media <NUM> is coiled and formed into a media pack, in general edge <NUM> will form an inlet end for the media pack and edge <NUM> an outlet end, although an opposite orientation is possible as discussed below with respect to <FIG>.

Adjacent edge <NUM> the sheets <NUM>, <NUM> are sealed to one another, for example by sealant, in this instance in the form of a sealant bead <NUM>, sealing the corrugated (fluted) sheet <NUM> and the facing sheet <NUM> together. Bead <NUM> will sometimes be referred to as a "single facer" bead, when it is applied as a bead between the corrugated sheet <NUM> and facing sheet <NUM>, to form the single facer or media strip <NUM>. Sealant bead <NUM> seals closed individual flutes <NUM> adjacent edge <NUM>, to passage of air therefrom.

Adjacent edge <NUM>, is provided sealant, in this instance in the form of a seal bead <NUM>. Seal bead <NUM> generally closes flutes <NUM> to passage of unfiltered fluid therein, adjacent edge <NUM>. Bead <NUM> would typically be applied as the media <NUM> is coiled about itself, with the corrugated sheet <NUM> directed to the inside. Thus, bead <NUM> will form a seal between a back side <NUM> of facing sheet <NUM>, and side <NUM> of the corrugated sheet <NUM>. The bead <NUM> will sometimes be referred to as a "winding bead" when it is applied as the strip <NUM> is coiled into a coiled media pack. If the media <NUM> were cut in strips and stacked, instead of coiled, bead <NUM> would be a "stacking bead.

In some applications, the corrugated sheet <NUM> is also tacked to the facing sheet <NUM> at various points along the flute length, as shown at lines 404a.

Referring to <FIG>, once the media <NUM> 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 <NUM>, would enter open flutes <NUM> adjacent end <NUM>. Due to the closure at end <NUM>, by bead <NUM>, the air would pass through the media shown by arrows <NUM>. It could then exit the media pack, by passage through open ends 415a of the flutes <NUM>, adjacent end <NUM> of the media pack. Of course operation could be conducted with air flow in the opposite direction, as discussed for example with respect to <FIG>. The point being that in typical air filter applications, at one end or face of the media pack unfiltered air flow goes in, and at an opposite end or face the filtered air flow goes out, with no unfiltered air flow through the pack or between the faces.

For the particular arrangement shown herein in <FIG>, the parallel corrugations 7a, 7b are generally straight completely across the media, from edge <NUM> to edge <NUM>. 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 <CIT> corrugation patterns which utilize somewhat semicircular (in cross section) inlet flutes adjacent narrow V-shaped (with curved sides) exit flutes are shown (see <FIG> and <FIG>, of <NUM>,<NUM>,<NUM>). In <CIT> 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> of Matsumoto '<NUM>. In <CIT> (<FIG>) flutes folded to have a rectangular cross section are shown, in which the flutes taper along their lengths. In <CIT> (<FIG>), 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 <CIT> 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 <NUM>, facing sheet <NUM> or both, can be provided with a fine fiber material on one or both sides thereof, for example in accord with <CIT>.

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.

Attention is again directed to <FIG> and <FIG>. The filter cartridge <NUM> includes a media pack <NUM> of straight flow through media, such as z-media <NUM>. The media pack <NUM> includes a first flow face <NUM> and an opposite second flow face <NUM>. The flutes <NUM>, <NUM> (<FIG>) extend in a direction between the opposite first and second flow faces <NUM>, <NUM>. A side wall <NUM> extends between the first and second flow faces <NUM>, <NUM>.

In this embodiment, the first flow face <NUM> corresponds to an inlet flow face, while the second flow face <NUM> corresponds to an outlet flow face.

The filter cartridge <NUM> includes a band <NUM> around the side wall <NUM>. In one example embodiment, the band <NUM> is circumscribing and against the side wall <NUM>, although alternatives are possible. The band <NUM> includes a plurality of alternating outward radial portions <NUM> and alternating inward radial portions <NUM>.

When the additional filter cartridge <NUM> is received within the second end cap <NUM> (alternatively, within the first end cap <NUM>), it forms a seal with the seal member <NUM> of the end cap <NUM>, <NUM> such that the inward radial portions <NUM> of the band <NUM> receive the seal member radial projections <NUM>; and the seal member radial recesses <NUM> receive the outward radial portions <NUM> of the band <NUM>. An alternative seal arrangement between the filter cartridge <NUM> and element <NUM> is discussed further below in connection with <FIG>.

As can be seen in <FIG> and <FIG>, the band <NUM> is oriented between the first flow face <NUM> and second flow face <NUM>. In this embodiment, the band <NUM> is also adjacent the first flow face <NUM>. Many embodiments are possible.

The band <NUM> can be part of an end piece <NUM>. The end piece <NUM> has a plate <NUM> extending radially from the first flow face <NUM>. The band <NUM> extends axially from the plate <NUM> and along the side wall <NUM>. In this example embodiment, the band <NUM> is generally perpendicular to the plate <NUM>. The plate <NUM> will extend over and cover an axial end of the second end cap <NUM>, when operably installed.

In an alternative embodiment of <FIG>, the element <NUM> and additional filter cartridge <NUM> are molded together in a single continuous end piece <NUM>, so that they are one unitary element pair <NUM>. In this embodiment, only the element <NUM> first end cap <NUM> includes the seal arrangement <NUM>.

The media pack <NUM> is preferably a coiled media pack. In this embodiment, the media pack <NUM> defines a central, open channel <NUM> extending between and through the first and second flow faces <NUM>, <NUM>. This channel <NUM> allows the rod <NUM> to extend through the filter cartridge <NUM> in order to engage the handle <NUM>.

In this embodiment, the media pack <NUM> has a cross-sectional shape that matches the cross-sectional shape of the openings <NUM>, <NUM> of the end caps <NUM>, <NUM>. In this example, the shape is round.

The additional filter cartridge <NUM> allows for flow of unfiltered air through the first flow face <NUM>. The media pack <NUM> removes particulate, and filtered air the flows through the second flow face <NUM> to reach the interior volume <NUM> of the filter element <NUM>. From there, the filtered air flows through the aperture <NUM> and the tube sheet <NUM>, through the venturi tube <NUM>, and into the downstream volume <NUM> (<FIG>) of the system <NUM>.

In general, the additional filter cartridge <NUM> helps to balance the filter gradient through the assembly <NUM> and add life to both elements <NUM>, <NUM>. Without the filter cartridge <NUM>, the element <NUM> would load in the region nearest the tube sheet <NUM>, but when the filter cartridge <NUM> is used, in some systems, the air will flow initially through the additional filter cartridge <NUM> first before flowing through the pleated media <NUM> of the element <NUM>. This leads to a more balanced filter gradient through the pleated media <NUM> and lengthens the life of the element <NUM>.

In the <FIG> embodiment, instead of a seal being formed between the additional filter cartridge <NUM> and filter element <NUM> at seal member <NUM>, the filter cartridge <NUM> has an end piece <NUM> secured to the second flow face <NUM>. The end piece <NUM> has an axially projecting ring <NUM>, which extends axially in a direction away from a remaining portion of the cartridge <NUM>. The ring <NUM> extend radially outwardly from sidewall <NUM> of the cartridge <NUM> and is sized to fit snuggly around (e.g., circumscribe) an outer diameter <NUM> of the end cap <NUM> to form a releasable radial seal <NUM> between and against an inside surface of the ring <NUM> and the outer diameter <NUM> of the end cap <NUM> of the element <NUM>.

In general, air to be filtered flows into the system <NUM> under the hoods <NUM> and into the upstream volume <NUM>. From there, the filtered air flows through the filter elements <NUM>. The media <NUM> filters the air, and the filtered air exits the filter elements <NUM> through the aperture <NUM> in the tube sheet <NUM> and then through the venturi tube <NUM>. The filtered air enters the downstream volume <NUM>, where it then flows to the downstream equipment a gas turbine.

In embodiments that include the additional filter cartridge <NUM>, if the filter elements <NUM> become clogged, the unfiltered air will bypass the pleated media <NUM> and flow through the media pack <NUM> of the additional filter cartridge <NUM>. The media pack <NUM> will filter the air, and the filtered air will flow into the interior volume <NUM> of the element <NUM> and then exit through the aperture <NUM> in the tube sheet <NUM>.

Periodically, the system <NUM> will pulse clean the elements <NUM> by emitting a pulse of air through the venturi tube <NUM>, where it will enter the interior volume <NUM> and knock of or blow off any dust or debris that has collected on the upstream side of the pleated media <NUM>.

After a period of operation, the system <NUM> will require servicing. To service the system <NUM>, the filter elements <NUM> will need to be removed and replaced with new filter elements <NUM>. To do that, the filter element <NUM> is released by pivoting the quick release handle <NUM> from a locked position (<FIG> and <FIG>) to an unlocked position, in which the handle <NUM> is pivoted to extend axially. The gasket washer <NUM> and handle <NUM> are removed from the rod <NUM>. In the embodiment of <FIG> and <FIG>, the assembly cover <NUM> is removed, and then the filter element <NUM> is removed from the tube sheet <NUM>. A new filter element <NUM> is provided. In embodiments that have elements <NUM> with identical seal members <NUM>, <NUM>, either end of the filter element <NUM> is oriented toward the tube sheet <NUM>. The new filter element <NUM> is sealed against the tube sheet <NUM> by creating a seal between the first (or second) end cap <NUM> and the tube sheet seal member <NUM>. This is done by engaging the outward radial portions <NUM> and inward radial portions <NUM> of the tube sheet seal member <NUM> with the radial recesses <NUM> and radial projections <NUM> of the seal member <NUM> of the filter element <NUM>.

The rod <NUM> is extended through the aperture <NUM> of the assembly cover <NUM>, while the outward radial portions <NUM> and inner radial portions <NUM> of the assembly cover form a seal with the radial recesses <NUM> and radial projections <NUM> of the seal member <NUM> of the second (or first) end cap <NUM> of the filter element <NUM>. The gasket washer <NUM> and handle <NUM> are then put in engagement with the rod <NUM>, and the handle <NUM> is pivoted into the locked position of <FIG> and <FIG> to secure the new filter element <NUM> in place.

For the embodiment of <FIG> and <FIG>, instead of forming a seal with the assembly cover <NUM>, the filter element <NUM> forms a seal with the additional filter cartridge <NUM>. This is done by engaging the outward radial portions <NUM> and inward radial portions <NUM> of the band <NUM> with the radial recesses <NUM> and radial projections <NUM> of the seal member <NUM> of the element <NUM>. The rod <NUM> passes through the channel <NUM> and engages the gasket washer <NUM> and handle <NUM>, in which the handle <NUM> is pivoted into the locked position to secure the element <NUM> to the tube sheet <NUM>. In <FIG>, the filter element <NUM> seals with the additional filter cartridge <NUM> at outer radial seal <NUM> along the outer diameter <NUM> of the end cap <NUM>.

In addition to the arrangement described above, all of which whose descriptions are incorporated here by reference, the following elements and systems are provided. The following arrangements can have any of the end caps, seal arrangements, and other various features as was previously described. Those features are not again described here.

In <FIG>, an alternate system is shown at <NUM>. The system <NUM> includes a filter arrangement <NUM>. The filter arrangement <NUM> can be embodied as a single element <NUM> (as described previously), or it can be an element pair <NUM> operably installed adjacent the tube sheet <NUM>. The filter element pair <NUM> includes a cylindrical element <NUM> and a conical element <NUM>, axially aligned and stacked end-to-end. Alternatively, the element pair <NUM> can include two cylindrical elements.

Yoke assembly <NUM> (<FIG>) releasably holds the filter arrangement <NUM> to the tube sheet <NUM>. The yoke assembly <NUM> includes tri-pod of legs <NUM>. Rod <NUM> extends from the leg tripod <NUM> at an end remote from the tube sheet <NUM>. Pivotable handle <NUM>, which is part of the yoke assembly <NUM>, is secured to the free end of the rod <NUM> and operates to removably secure the filter arrangement <NUM> to the tube sheet <NUM>. The handle <NUM> can be similar to the handle as described in <CIT> and <CIT>.

The filter element <NUM> has a first end cap <NUM> and an opposite second end cap <NUM>. In embodiments in which the filter arrangement <NUM> includes only a single element (such as element <NUM>), the first end cap <NUM> will form a seal with the tube sheet <NUM>, and can include the seal arrangement <NUM> described above in connection with <FIG>. In the embodiment shown, the first end cap <NUM> is against the non-tube sheet end of the element <NUM>. The tube sheet end <NUM> of the element <NUM> may include any of the various seal arrangements described above in connection with <FIG>, such as seal arrangement <NUM>. Alternatively, it may be a standard axial seal.

The second end cap <NUM> of the filter element <NUM> includes a center, integrated gasket <NUM>. The gasket <NUM> is made from a soft material and includes a seal member <NUM>. The seal member <NUM> surrounds a rod-receiving through-aperture <NUM>, through which the rod <NUM> passes.

The seal member <NUM> has an inwardly radially directed seal surface <NUM> and a thickness that varies along the seal member surface <NUM>. The thickness varies in a radial direction along the seal member surface <NUM>. It should be understood that the seal surface <NUM> surrounds the through-aperture <NUM>.

In <FIG>, the radially directed seal surface <NUM> can be seen to include a plurality of outwardly projecting projections <NUM> and a plurality of inwardly projecting recesses <NUM>. These projections <NUM> and recesses <NUM> can be curved. In this example, a length of the seal member surface <NUM> is constant in an axial direction.

The second end cap <NUM> has a recessed section <NUM> projecting inwardly into the filter interior <NUM>. The integrated gasket <NUM> is centered in the recessed section <NUM>.

In the example shown, the integrated gasket <NUM> has an outer diameter less than that of the outer diameter of the second end cap <NUM>. For example, the diameter of the integrated gasket <NUM> is less than <NUM>%, indeed less than <NUM>%, and often less than <NUM>% of an outer diameter of the second end cap <NUM>.

In the system <NUM>, a portion of the rod <NUM> has a plurality of alternating outward radial sections <NUM> and alternating inward radial sections <NUM>.

The second end cap <NUM> receives the rod <NUM> through aperture <NUM> in the gasket <NUM> in that: the rod inward radial sections <NUM> receive the seal member radial projections <NUM>; and the seal member radial recesses <NUM> receive the rod outward radial sections <NUM>.

The contact between the rod <NUM> and the gasket <NUM> helps to increase the contact between the filter element gasket <NUM> and the rod <NUM> to ensure good sealing over the entire life time of the filter element <NUM>. The number of projections <NUM> and recesses <NUM> can vary according to the sealing compression factor that is needed. A pressure washer can be used to help spread the load of the clamping system onto the second end cap <NUM> of the filter element <NUM>.

In addition to the arrangement described above, the following elements and systems are provided. The following arrangements can have any of the end caps, seal arrangements, and other various features as was previously described. Those features are not again described here.

Now referring to <FIG>, a filter cartridge or element (e.g., primary or main) is shown at reference number <NUM>. The filter cartridge <NUM> as shown includes a first end piece (e.g., cap) <NUM>, a second end piece (e.g., cap) <NUM>, filter media <NUM>, and a liner <NUM>. The filter media <NUM> includes a first end 2356a and a second end 2356b. In general, the filter media first end 2356a can be embedded in the first end cap <NUM>, and the filter media second end 2356b can be embedded in the second end cap <NUM>. In addition, the liner <NUM> includes a liner first end 2358a and a liner second end 2358b. The liner first end 2358a can also be embedded in the first end cap <NUM>, and the liner second end 2358b can be embedded in the second end cap <NUM>. In addition, the filter media <NUM> can be provided as supported by the liner <NUM>. The filter media <NUM> can be provided as cylindrical or conical pleated media, or as any other type of media configuration that provides the filter cartridge <NUM> with a central open volume <NUM>.

Now referring to <FIG>, the first end piece (e.g., cap) <NUM> is shown in detail. The first end cap <NUM> includes a central open volume <NUM> that is in communication with the filter element central open volume <NUM>. Accordingly, the first end cap <NUM> can be characterized as an open end cap <NUM>. The second end cap <NUM> can also be an open end cap.

The filter element <NUM> can be used in, for example, the system <NUM> of <FIG> or <FIG>. The seal members <NUM>, <NUM>, as characterized above, are further defined below, and this further definition can apply to any of the previously described seal members <NUM>, <NUM>.

The open end cap <NUM> includes a first end <NUM>, a second end <NUM>, and an internal surface <NUM> extending between the first end <NUM> and the second end <NUM>. The internal surface <NUM> forms the central open volume <NUM>, and can be constructed to engage and seal against the tube sheet seal member <NUM> (<FIG>) having a wavy wall. The internal surface <NUM> can form an internally directed radial seal.

The internal surface <NUM> as shown includes a lead in region <NUM>, an optional peripherally uniform radial seal region <NUM>, a transition region <NUM>, and a peripherally non-uniform radial seal region <NUM>. The optional peripherally uniform seal radial seal region <NUM> can be omitted from the filter element <NUM>, and is provided in the event it is desirable for the filter element <NUM> to fit both a filter cartridge seal surface that can be characterized as a wavy wall tube sheet seal member and a prior art air tube sheet seal member having a peripherally uniform seal surface about an axis X.

The lead in region <NUM>, the transition region <NUM>, and the peripherally non-uniform radial seal region <NUM> can be characterized as having a plurality of radially outwardly projecting and axially extending portions <NUM> alternating with a plurality of radially inwardly projecting and axially extending portions <NUM>. These portions <NUM> and <NUM> can be provided extending axially along each of regions <NUM>, <NUM>, and <NUM> and not along region <NUM> if region <NUM> is present. The radially outwardly projecting and axially extending portions <NUM> can be characterized as troughs <NUM>, and the and the radially inwardly projecting and axially extending portions <NUM> can be characterized as peaks or ridges <NUM>. The lobes <NUM> formed by the peaks <NUM> between adjacent troughs <NUM> can be provided so that they fit into the corresponding troughs (inward radial portions) <NUM> in the tube sheet seal member <NUM> (<FIG>). Similarly, the troughs <NUM> are provided so that they receive the peaks (outward radial portions) <NUM> in the tube sheet seal member <NUM>. It should be appreciated that the reference to "outwardly" and "inwardly" refer to a direction either away from or toward the central axis X. Thus, the outwardly projecting and axially extending portions <NUM> can be referred to as troughs <NUM>, and the inwardly projecting and axially extending portions <NUM> can be referred to as peaks <NUM>. The size and shape of the troughs <NUM> and peaks <NUM> can be altered and adjusted throughout the lead in region <NUM>, the transition region <NUM>, and the radially seal region <NUM> in order to ease the insertion of the filter element <NUM> onto the tube sheet seal member <NUM>.

The radial seal region <NUM> includes a wavy wall seal member surface <NUM> that also includes a plurality of lobes <NUM>. The wavy wall seal member surface can be characterized in terms of "pitch" which is the distance from peak to adjacent peak of the lobes <NUM>. In the case of the wavy wall seal member surface <NUM>, the pitch can be defined as the distance between adjacent peaks. Alternatively, the pitch can be defined as the distance between the adjacent troughs. The wavy wall seal member surface <NUM> can be characterized as having a pitch that allows the service provider (installer of the filter element) with a degree of indexing that allows the service provider to correctly index the filter element within the housing without having to re-grip the filter element. As the filter cartridge <NUM> is introduced into the wavy tube sheet seal member, the lead in region <NUM> engages the wavy wall of the tube sheet seal member <NUM> thereby indexing the filter cartridge <NUM> into the correct orientation for further axial insertion. The peripherally uniform radial seal surface <NUM>, if present, engages the wavy wall of the tube sheet seal member <NUM> with continued axial insertion. Further axial insertion results in the transition region <NUM> engaging the wavy wall to help further orient the filter cartridge <NUM> and ease the transition to the radial seal region <NUM> engaging the wavy wall of the tube sheet seal member <NUM> where a radially directed seal is created.

It should be appreciated that for the filter cartridge <NUM>, the peripherally non-uniform radial seal surface <NUM> and the peripherally uniform radial seal surface <NUM> (if present) are recessed from the first end <NUM> of the open end cap <NUM>. Furthermore, the seal surfaces <NUM> and <NUM> can be characterized as provided inside of the filter media <NUM>. In addition, by recessing the seal surfaces <NUM> and <NUM> from the first end <NUM>, the seal surfaces <NUM> and <NUM> are protected from dust or debris when the filter cartridge <NUM> is set on a dirty surface. For example, the seal surfaces <NUM> and <NUM> can be axially recessed at least about <NUM> millimeter from the first end <NUM>.

In some embodiments, the second end cap <NUM> can have an identical construction as the first end cap <NUM> as characterized above.

Principles according to the present disclosure relate to interactions between filter cartridges and air cleaner systems, in advantageous manners to achieve certain, selected, desired results discussed below. The filter cartridge would generally include a filter media therein, through which air and other gases pass, during a filtering operation. The media can be of a variety of types and configurations, and can be made from using a variety of materials. For example, pleated media arrangements can be used in cartridges according to the principles of the present disclosure, as discussed below.

The principles are particularly well adapted for use in situations in which the media is quite deep in extension between the inlet and outlet ends of the cartridge, but alternatives are possible. Also, the principles are often used in cartridges having relatively large cross-dimension sizes. With such arrangements, alternate media types to pleated media will often be desired.

In this section, examples of some media arrangements that are usable with the techniques described herein are provided. It will be understood, however, that a variety of alternate media types can be used. The choice of media type is generally one of preference for: availability; function in a given situation of application, ease of manufacturability, etc. and the choice is not necessarily specifically related to the overall function of selected ones of various filter cartridge/air cleaner interaction features characterized herein.

Media pack arrangements using filter media having media ridges (flutes) secured to facing media is described above with respect to <FIG>.

Attention is now directed to <FIG>, in which z-filter media; i.e., a z-filter media construction <NUM>, utilizing a regular, curved, wave pattern corrugated sheet <NUM>, and a non-corrugated flat sheet <NUM>, i.e., a single facer strip is schematically depicted. The distance D1, between points <NUM> and <NUM>, defines the extension of flat media <NUM> in region <NUM> underneath a given corrugated flute <NUM>. The length D2 of the arcuate media for the corrugated flute <NUM>, over the same distance D1 is of course larger than D1, due to the shape of the corrugated flute <NUM>. For a typical regular shaped media used in fluted filter applications, the linear length D2 of the media <NUM> between points <NUM> and <NUM> will often be at least <NUM> times D1. Typically, D2 would be within a range of <NUM> - <NUM> times D1, inclusive. One particularly convenient arrangement for air filters has a configuration in which D2 is about <NUM> - <NUM> x D1. Such media has, for example, been used commercially in Donaldson Powercore™ Z-filter arrangements. Another potentially convenient size would be one in which D2 is about <NUM> - <NUM> times D1. Herein the ratio D2/D1 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>, 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>.

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.

It is noted that alternative flute definitions such as those characterized in <CIT>; and published as <CIT> ; <CIT> and published as <CIT>; and/or <CIT> published as <CIT> can be used, with air cleaner features as characterized herein below. The complete disclosures of each of <CIT>, <CIT> and <CIT> are referenced here.

Another media variation comprising fluted media with facing media secured thereto, can be used in arrangements according to the present disclosure, in either a stacked or coiled form, is described in <CIT>, and referenced here.

In <FIG>, one example of a manufacturing process for making a media strip (single facer) corresponding to strip <NUM>, <FIG> is shown. In general, facing sheet <NUM> and the fluted (corrugated) sheet <NUM> having flutes <NUM> are brought together to form a media web <NUM>, with an adhesive bead located therebetween at <NUM>. The adhesive bead <NUM> will form a single facer bead <NUM>, <FIG>. An optional darting process occurs at station <NUM> to form center darted section <NUM> located mid-web. The z-filter media or Z-media strip <NUM> can be cut or slit at <NUM> along the bead <NUM> to create two pieces or strips <NUM>, <NUM> of z-filter media <NUM>, 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> are described in <CIT>.

Still in reference to <FIG>, before the z-filter media <NUM> is put through the darting station <NUM> and eventually slit at <NUM>, it must be formed. In the schematic shown in <FIG>, this is done by passing a sheet of filter media <NUM> through a pair of corrugation rollers <NUM>, <NUM>. In the schematic shown in <FIG>, the sheet of filter media <NUM> is unrolled from a roll <NUM>, wound around tension rollers <NUM>, and then passed through a nip or bite <NUM> between the corrugation rollers <NUM>, <NUM>. The corrugation rollers <NUM>, <NUM> have teeth <NUM> that will give the general desired shape of the corrugations after the flat sheet <NUM> passes through the nip <NUM>. After passing through the nip <NUM>, the sheet <NUM> becomes corrugated across the machine direction and is referenced at <NUM> as the corrugated sheet. The corrugated sheet <NUM> is then secured to facing sheet <NUM>. The corrugation process may involve heating the media, in some instances.

Still in reference to <FIG>, the process also shows the facing sheet <NUM> being routed to the darting process station <NUM>. The facing sheet <NUM> is depicted as being stored on a roll <NUM> and then directed to the corrugated sheet <NUM> to form the Z-media <NUM>. The corrugated sheet <NUM> and the facing sheet <NUM> would typically be secured together by adhesive or by other means (for example by sonic welding).

Referring to <FIG>, an adhesive line <NUM> is shown used to secure corrugated sheet <NUM> and facing sheet <NUM> together, as the sealant bead. Alternatively, the sealant bead for forming the facing bead could be applied as shown as 516a. If the sealant is applied at 516a, it may be desirable to put a gap in the corrugation roller <NUM>, and possibly in both corrugation rollers <NUM>, <NUM>, to accommodate the bead 516a.

Of course the equipment of <FIG> can be modified to provide for the tack beads <NUM>, <FIG>, 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 <NUM>, <NUM>. One useful corrugation pattern will be a regular curved wave pattern corrugation, of straight flutes or ridges, as defined herein above. A typical regular curved wave pattern used, would be one in which the distance D2, as defined above, in a corrugated pattern is at least <NUM> times the distance D1 as defined above. In example applications, typically D2 = <NUM> - <NUM> x D1, 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> can be used to create the center darted section <NUM>. <FIG> shows, in cross-section, one of the flutes <NUM> after darting and slitting.

A fold arrangement <NUM> can be seen to form a darted flute <NUM> with four creases 541a, 541b, 541c, 541d. The fold arrangement <NUM> includes a flat first layer or portion <NUM> that is secured to the facing sheet <NUM>. A second layer or portion <NUM> is shown pressed against the first layer or portion <NUM>. The second layer or portion <NUM> is preferably formed from folding opposite outer ends <NUM>, <NUM> of the first layer or portion <NUM>.

Still referring to <FIG>, two of the folds or creases 541a, 541b 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 <NUM>, when the fold <NUM> is viewed in the orientation of <FIG>. The term "inwardly directed" is meant to refer to the fact that the fold line or crease line of each crease 541a, 541b, is directed toward the other.

In <FIG>, creases 541c, 541d, will generally be referred to herein as "lower, outwardly directed" creases. The term "lower" in this context refers to the fact that the creases 541c, 541d are not located on the top as are creases 541a, 541b, in the orientation of <FIG>. The term "outwardly directed" is meant to indicate that the fold lines of the creases 541c, 541d are directed away from one another.

The terms "upper" and "lower" as used in this context are meant specifically to refer to the fold <NUM>, when viewed from the orientation of <FIG>. That is, they are not meant to be otherwise indicative of direction when the fold <NUM> is oriented in an actual product for use.

Based upon these characterizations and review of <FIG>, it can be seen that a regular fold arrangement <NUM> according to <FIG> 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 <NUM> can also be seen pressed against the second layer or portion <NUM>. The third layer or portion <NUM> is formed by folding from opposite inner ends <NUM>, <NUM> of the third layer <NUM>.

Another way of viewing the fold arrangement <NUM> is in reference to the geometry of alternating ridges and troughs of the corrugated sheet <NUM>. The first layer or portion <NUM> is formed from an inverted ridge. The second layer or portion <NUM> 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>, in a preferred manner, are described in <CIT>, incorporated herein by reference. Techniques for coiling the media, with application of the winding bead, are described in <CIT> and published as <CIT>.

Alternate approaches to darting the fluted ends closed are possible. Such approaches can involve, for example: darting which is not centered in each flute; and, rolling, pressing or folding over the various flutes. In general, darting involves folding or otherwise manipulating media adjacent to fluted end, to accomplish a compressed, closed, state.

Techniques described herein are particularly well adapted for use in media packs that result from a step of coiling a single sheet comprising a corrugated sheet/facing sheet combination, i.e., a "single facer" strip. However, they can also be made into stacked arrangements.

Coiled media or 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 or media pack. Typical shapes are circular as described in <CIT>. 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 <CIT>, and <CIT>, published as <CIT>.

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 or media pack can be provided with a variety of different definitions. In many arrangements, the ends or end faces are generally flat (planer) and perpendicular to one another. In other arrangements, one or both of the end faces include tapered, for example, 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.

In <FIG>, a coiled media pack (or coiled media) <NUM> constructed by coiling a single strip of single faced media is depicted, generally. The particular coiled media pack depicted is an oval media pack 550a, specifically a racetrack shaped media pack <NUM>. The tail end of the media, at the outside of the media pack <NUM> is shown at 551x. It will be typical to terminate that tail end along straight section of the media pack <NUM> for convenience and sealing. Typically, a hot melt seal bead or seal bead is positioned along that tail end to ensure sealing. In the media pack <NUM>, the opposite flow (end) faces are designated at <NUM>, <NUM>. One would be an inlet flow face, the other an outlet flow face.

In <FIG>, there is (schematically) shown a step of forming stacked z-filter media (or media pack) from strips of z-filter media, each strip being a fluted sheet secured to a facing sheet. Referring to <FIG>, single facer strip <NUM> is being shown added to a stack <NUM> of strips <NUM> analogous to strip <NUM>. Strip <NUM> can be cut from either of strips <NUM>, <NUM>, <FIG>. At <NUM>, <FIG>, application of a stacking bead <NUM> is shown, between each layer corresponding to a strip <NUM>, <NUM> at an opposite edge from the single facer bead or seal. Stacking can also be done with each layer being added to the bottom of the stack, as opposed to the top.

Referring to <FIG>, each strip <NUM>, <NUM> has front and rear edges <NUM>, <NUM> and opposite side edges 568a, 568b. Inlet and outlet flutes of the corrugated sheet/facing sheet combination comprising each strip <NUM>, <NUM> generally extend between the front and rear edges <NUM>, <NUM>, and parallel to side edges 568a, 568b.

Still referring to <FIG>, in the media or media pack <NUM> being formed, opposite flow faces are indicated at <NUM>, <NUM>. The selection of which one of faces <NUM>, <NUM> is the inlet end face and which is the outlet end face, during filtering, is a matter of choice. In some instances the stacking bead <NUM> is positioned adjacent the upstream or inlet face <NUM>; in others the opposite is true. The flow faces <NUM>, <NUM>, extend between opposite side faces <NUM>, <NUM>.

The stacked media configuration or pack <NUM> shown being formed in <FIG>, is sometimes referred to herein as a "blocked" stacked media pack. The term "blocked" in this context, is an indication that the arrangement is formed to a rectangular block in which all faces are <NUM>° relative to all adjoining wall faces. For example, in some instances the stack can be created with each strip <NUM> being slightly offset from alignment with an adjacent strip, to create a parallelogram or slanted block shape, with the inlet face and outlet face parallel to one another, but not perpendicular to upper and bottom surfaces.

In some instances, the media or media pack will be referenced as having a parallelogram shape in any cross-section, meaning that any two opposite side faces extend generally parallel to one another.

It is noted that a blocked, stacked arrangement corresponding to <FIG> is described in the prior art of <CIT>. It is also noted that stacked arrangements are described in <CIT>; <CIT>; <CIT>; and <CIT> and published as <CIT>. It is noted that a stacked arrangement shown in <CIT>, published as <CIT> is a slanted stacked arrangement.

It is also noted that, in some instances, more than one stack can be incorporated into a single media pack. Also, in some instances, the stack can be generated with one or more flow faces that have a recess therein, for example, as shown in <CIT>.

Alternate types of media arrangements or packs that involve flutes between opposite ends extending between can be used with selected principles according to the present disclosure. An example of such alternate media arrangement or pack is depicted in <FIG>. The media of <FIG> is analogous to one depicted and described in <CIT>; and as can sometimes found in arrangements available under the mark "IQORON" from Mann & Hummel.

Referring to <FIG>, the media or media pack is indicated generally at <NUM>. The media or media pack <NUM> comprises a first outer pleated (ridged) media loop <NUM> and a second, inner, pleated (ridged) media loop <NUM>, each with pleat tips (or ridges) extending between opposite flow ends. The view of <FIG> is toward a media pack (flow) end <NUM>. The end <NUM> depicted, can be an inlet (flow) end or an outlet (flow) end, depending on selected flow direction. For many arrangements using principles characterized having the media pack <NUM> would be configured in a filter cartridge such that end <NUM> is an inlet flow end.

Still referring to <FIG>, the outer pleated (ridged) media loop <NUM> is configured in an oval shape, though alternatives are possible. At <NUM>, a pleat end closure, for example molded in place, is depicted closing ends of the pleats or ridges <NUM> at media pack end <NUM>.

Pleats, or ridges <NUM> (and the related pleat tips) are positioned surrounded by and spaced from loop <NUM>, and thus pleated media loop <NUM> is also depicted in a somewhat oval configuration. In this instance, ends 582e of individual pleats or ridges 582p in a loop <NUM> are sealed closed. Also, loop <NUM> surrounds the center 582c that is closed by a center strip <NUM> of material, typically molded-in-place.

During filtering, when end <NUM> is an inlet flow end, air enters gap <NUM> between the two loops of media <NUM>, <NUM>. The air then flows either through loop <NUM> or loop <NUM>, as it moves through the media pack <NUM>, with filtering.

In the example depicted, loop <NUM> is configured slanting inwardly toward loop <NUM>, in extension away from end <NUM>. Also spacers <NUM> are shown supporting a centering ring <NUM> that surrounds an end of the loop <NUM>, for structural integrity.

In <FIG>, an end <NUM> of the cartridge <NUM>, opposite end <NUM> is viewable. Here, an interior of loop <NUM> can be seen, surrounding an open gas flow region <NUM>. When air is directed through cartridge <NUM> in a general direction toward end <NUM> and away from end <NUM>, the portion of the air that passes through loop <NUM> will enter central region <NUM> and exit therefrom at end <NUM>. Of course air that has entered media loop <NUM>, <FIG> during filtering would generally pass around (over) an outer perimeter 586p of end <NUM>.

In <FIG> a schematic cross sectional view of cartridge <NUM> is provided. Selected identified and described features are indicated by like reference numerals.

It will be understood from a review of <FIG>, the above description, that the cartridge <NUM> described, is generally a cartridge which has media tips extending in a longitudinal direction between opposite flow ends <NUM>, <NUM>.

In the arrangement of <FIG>, the media pack <NUM> is depicted with an oval, in particular racetrack, shaped perimeter. It is depicted in this manner, since the air filter cartridges in many examples below also have an oval or racetrack shaped configuration. However, the principles can be embodied in a variety of alternate peripheral shapes.

Herein, in <FIG>, some schematic, fragmentary, cross-sectional views are provided of still further alternate variations of media types that can be used in selected applications of the principles characterized herein. Certain examples are described in <CIT> and owned by the Assignee of the present disclosure, Donaldson Company, Inc. In general, each of the arrangements of <FIG> represents a media type that can be stacked or coiled into an arrangement that has opposite inlet and outlet flow ends (or faces), with straight through flow.

In <FIG>, an example media arrangement <NUM> from <CIT>(<NUM>) is depicted, in which an embossed sheet <NUM> is secured to a non-embossed sheet <NUM>, then stacked and coiled into a media pack, with seals along opposite edges of the type previously described for <FIG> herein.

In <FIG>, an alternate example media pack <NUM> from <CIT> is depicted, in which a first embossed sheet <NUM> is secured to a second embossed sheet <NUM> and then formed into a stacked or coiled media pack arrangement, having edge seals generally in accord with <FIG> herein.

In <FIG>, a third example media arrangement <NUM> from <CIT> is depicted. Edge seals can be conducted in either the upstream end or the downstream end, or in some instances both. Especially when the media is likely to encounter chemical material during filtering, it may be desirable to avoid a typical adhesive or sealant.

In <FIG>, a cross-section is depicted in which the fluted sheet X has various embossments on it for engagement with the facing sheet Y. Again these can be separate, or sections of the same media sheet.

In <FIG>, a schematic depiction of such an arrangement between the fluted sheet X and facing sheet Y is also shown.

In <FIG>, a still further variation of such a principle is shown between a fluted sheet X and a facing sheet Y. These are meant to help understand how a wide variety of approaches are possible.

In <FIG>, still another possible variation in fluted sheet X and facing sheet Y is shown.

In <FIG>, an example media arrangement <NUM> is depicted, in which a fluted sheet <NUM> is secured to a facing sheet <NUM>. The facing sheet <NUM> may be a flat sheet. The media arrangement <NUM> can then be stacked or coiled into a media pack, with seals along opposite edges of the type previously described for <FIG> herein. In the embodiment shown, the flutes <NUM> of fluted sheet <NUM> have an undulating ridgeline including a series of peaks <NUM> and saddles <NUM>. The peaks <NUM> of adjacent flutes <NUM> can be either aligned as shown in <FIG> or offset. Further the peak height and/or density can increase, decrease, or remain constant along the length of the flutes <NUM>. The ratio of the peak flute height to saddle flute height can vary from about <NUM>, typically from <NUM> to about <NUM>.

It is noted that there is no specific requirement that the same media be used for the fluted sheet section and the facing sheet section. A different media can be desirable in each, to obtain different effects. For example, one may be a cellulose media, while the other is a media containing some non-cellulose fiber. They may be provided with different porosity or different structural characteristics, to achieve desired results.

A variety of materials can be used. For example, the fluted sheet section or the facing sheet section can include a cellulose material, synthetic material, or a mixture thereof. In some embodiments, one of the fluted sheet section and the facing sheet section includes a cellulose material and the other of the fluted sheet section and facing sheet section includes a synthetic material.

Synthetic material(s) can include polymeric fibers, such as polyolefin, polyamide, polyester, polyvinyl chloride, polyvinyl alcohol (of various degrees of hydrolysis), and polyvinyl acetate fibers. Suitable synthetic fibers include, for example, polyethylene terephthalate, polyethylene, polypropylene, nylon, and rayon fibers. Other suitable synthetic fibers include those made from thermoplastic polymers, cellulosic and other fibers coated with thermoplastic polymers, and multi-component fibers in which at least one of the components includes a thermoplastic polymer. Single and multi-component fibers can be manufactured from polyester, polyethylene, polypropylene, and other conventional thermoplastic fibrous materials.

The examples of <FIG>, are meant to indicate generally that a variety alternate media packs can be used in accord with the principles herein. Attention is also directed to <CIT> with respect to the general principles of construction and application of some alternates media types.

Additional examples of alternative types of media arrangements or packs that involve filtration media having flutes extending between opposite ends or flow faces in a straight through flow configuration are depicted in <FIG>. The flutes can be considered inlet flutes when they are arranged to receive dirty air via an inlet flow face, and they can be considered outlet flutes when they are arranged to permit filtered air to flow out via an outlet flow face.

The filtration media <NUM> depicted in <FIG>, which is analogous to ones depicted in <CIT> and <CIT> assigned to Mann+Hummel GmbH, is illustrated in an arrangement that shows how the filtration media <NUM> can be formed into a media pack arrangement <NUM>.

The media pack arrangement <NUM> can be considered as having relatively long or deep pleats from an inlet flow face <NUM> to an outlet flow face <NUM>, and can also have varying pleat depths as illustrated. As the depth of pleats of a media pack increases, there is a tendency of the filtration media to collapse on each other thereby causing masking. Masking is undesirable because masked filtration media tends to no longer be available for filtration thereby decreasing dust holding capacity and flow through the media pack, and also potentially increasing pressure drop across the media pack. In order to reduce masking and to help the filtration media retain its shape, support structures are known to be applied to pleated media. In <FIG> and <FIG>, support sections or spacers <NUM> are provided. It should be appreciated that <FIG> and <FIG> are illustrated in a folded configuration <NUM> having pleat folds <NUM>, but are expanded or separated to show how the filtration media <NUM> and the support sections or spacers <NUM> can be arranged.

As illustrated in <FIG>, the filtration media <NUM> extends between a first side <NUM> and a second side <NUM>. Although only one support section <NUM> is shown on each pleat face <NUM>, it should be appreciated that multiple support sections <NUM> can be arranged along each pleat face <NUM> so that when the filtration media <NUM> is arranged into a media pack as illustrated in <FIG> as media pack <NUM>, the volume between each of the support sections <NUM> can be considered flutes extending between the inlet flow face <NUM> and the outlet flow face <NUM>. The support sections <NUM> can be arranged on each flow face <NUM> so that opposite support sections <NUM> contact or engage each other to help maintain the media pack shape while also limiting the amount of filtration media that would be contacted by the support sections <NUM>, as illustrated in <FIG>. Furthermore, by providing that the support sections <NUM> have adhesive properties, the support sections <NUM> can be provided so that opposing support sections <NUM> can adhere to each other when the filtration media <NUM> is arranged into the media pack <NUM>.

The support sections <NUM> can be arranged in a tapered configuration where support sections <NUM> have a cross section at an interior fold <NUM> and wherein the cross section increases toward an exterior fold <NUM>. In this context, the phrase "interior fold" refers to the side of the media that forms an acute angle, and the phrase "exterior fold" refers to the side of the media that forms an obtuse angle when the media is arranged into a media pack. Furthermore, the reference to changing the cross section of the support sections <NUM> can refer to one or both of the height that the support section extends away from the media to which it is adhered and also to the width along the media to which it is adhered to in a direction toward or away from other support sections across adjacent flutes. Changing the shape of the support sections <NUM> can help maintain the shape of the media pack and the resulting flutes, and can help reduce the amount of media that would otherwise be contacted by the support sections <NUM> if they were not arranged in a tapered configuration. In addition, the support sections <NUM> can be arranged in a non-tapered configuration. As illustrated in <FIG>, the support sections <NUM> can be provided so that they extend over the exterior folds <NUM> although it is not necessary for the support sections <NUM> to extend over the exterior folds. In addition, it is not necessary for the support sections <NUM> to extend into the interior folds <NUM>, although, if desired, the support sections <NUM> can be provided so that they extend into the interior folds <NUM>.

The support sections <NUM> can be applied to the filtration media <NUM> as adhesive extruded onto the filtration media <NUM> where the adhesive forms the support sections <NUM>. Before the adhesive has a chance to fully cure, the filtration media <NUM> can be folded into the media pack arrangement <NUM>, which may or may not have varying pleat depths. By forming the media pack arrangement <NUM> before the adhesive has fully cured, the opposing support sections <NUM> can become bonded or adhered to each other thereby forming flutes extending between the inlet flow face <NUM> and the outlet flow face <NUM>.

It should be appreciated that the filtration media <NUM> can be provided with deformation, such as corrugations, extending across the media. The direction of deformation, such as corrugation, can be parallel or perpendicular to the pleat fold direction.

The filtration media <NUM> depicted in <FIG> is analogous to filtration media depicted in <CIT>, as another example of a media pack arrangement <NUM> having inlet and outlet flutes in a straight through flow arrangement.

The filtration media pack arrangement <NUM> can be formed by folding the filtration media <NUM> to form an inlet flow face <NUM> and an outlet flow face <NUM>. The pleat tips <NUM> form the inlet flow face <NUM>, and the pleat tips <NUM> form the outlet flow face <NUM>. Adhesive beads <NUM> and <NUM>, which may be continuous or discontinuous, extend along the filtration media <NUM> in multiple lines across the filtration media <NUM> from a media first side <NUM> to a media second side <NUM>. The adhesive beads <NUM> and <NUM> along the media first side <NUM> and along the media second side <NUM> can be thickened, if desired, and can be arranged to provide an edge seal along the media first side <NUM> and the media second side <NUM>. By providing that the adhesive beads <NUM> and <NUM> adhere to each other as the filtration media <NUM> is folded, inlet flutes <NUM> and outlet flutes <NUM> can be formed in the straight through media pack arrangement <NUM>.

A similar type of filtration media pack arrangement is commercially available under the name Enduracube from Baldwin Filters, Inc. The filtration media pack available under the name Enduracube from Baldwin Filters, Inc. is arranged in a pleated configuration forming inlet flutes and outlet flutes extending between an inlet flow face and an outlet flow face.

Many of the techniques characterized herein will preferably be applied when the media is oriented for filtering between opposite flow ends of the cartridge is media having flutes or pleat tips that extend in a direction between those opposite ends. However, alternatives are possible. The techniques characterized herein with respect to seal arrangement definition can be applied in filter cartridges that have opposite flow ends, with media positioned to filter fluid flow between those ends, even when the media does not include flutes or pleat tips extending in a direction between those ends. The media, for example, can be depth media, can be pleated in an alternate direction, or it can be a non-pleated material.

It is indeed the case, however, that the techniques characterized herein are particularly advantageous for use with cartridges that are relatively deep in extension between flow ends, usually at least <NUM>, typically at least <NUM> , often at least <NUM>, sometimes at least <NUM>, and in some instances <NUM> or more, and are configured for large loading volume during use. These types of systems will typically be ones in which the media is configured with pleat tips or flutes extending in a direction between opposite flow ends.

It is also noted that while the techniques described herein were typically developed for advantageous application and arrangements involving media packs with straight through flow configurations, the techniques can be applied to advantage in other systems. For example, the techniques can be applied when the cartridge comprises media surrounding a central interior, in which the cartridge has an open end. Such arrangements can involve "forward flow" in which air to be filtered enters the central open interior by passage through the media, and the exits through the open end; or, with reverse flow in which air to be filtered enters the open end and then turns and passes through the media. A variety of such arrangements are possible, including pleated media and alternate types of media. Configurations usable would include cylindrical and conical, among others.

<FIG> is a perspective view of a filter arrangement <NUM>, constructed in accordance with principles of this disclosure. In general, the filter arrangement <NUM> includes a first open end cap <NUM>, an opposite second end cap <NUM>, a tubular section of filter media <NUM> extending between the end caps <NUM>, <NUM>, and a filter cartridge <NUM> mounted within an opening in the second end cap <NUM>.

The filter media <NUM> can be many different types, depending on the application. In many useful embodiments, the filter media <NUM> is pleated. In many useful embodiments, the filter media <NUM> is pleated cellulose. The filter media <NUM> is tubular and surrounds an open interior volume <NUM>. The tubular shape can have a round cross-section, or it can have other shapes such as oval.

The first end cap <NUM> has an opening <NUM> in communication with the interior volume <NUM>. The second end cap <NUM> has an opening <NUM> that accommodates the filter cartridge <NUM>.

The end caps <NUM>, <NUM> are secured to the ends of the filter media <NUM>. This can be done by molding the end caps <NUM>, <NUM> directly onto the media <NUM>, but many alternatives are possible.

In <FIG>, the first end cap <NUM> includes a seal member <NUM> to form a releasable seal with a mating part, such as an outlet tube. The seal member <NUM> can be an inwardly directed radial seal member <NUM>. The seal member <NUM> can be molded as part of the first end cap <NUM>, with a soft polyurethane foam. Alternative seal arrangements are possible, including pinch seals or axial seals.

The filter cartridge <NUM> includes a media pack <NUM>. The media pack <NUM> can include many different types of media including membrane, depth media, foam media, pleated, straight-through flow media, z-media, fluted media, and any of the various types described in Section II of this disclosure, above.

In the example shown in the FIGS. , the media pack <NUM> includes a first flow face <NUM> and an opposite second flow face <NUM> for straight through flow.

Flutes <NUM>, <NUM> (<FIG>) extend in a direction between the opposite first and second flow faces <NUM>, <NUM>. A side wall <NUM> (<FIG>) extends between the first and second flow faces <NUM>, <NUM>. The side wall <NUM> forms an outer periphery of the cartridge <NUM> and can include a hard shell, in some embodiments. In other embodiments, the side wall <NUM> is the outer wall of the media pack <NUM> and is free of a shell.

The filter cartridge <NUM> can either be removable and replaceable in the opening <NUM> of the second end cap <NUM>, or it may be non-removably / permanently mounted therein.

In embodiments in which the cartridge <NUM> is non-removably mounted, the end cap <NUM> and filter cartridge <NUM> are molded together in a single continuous end piece <NUM>, so that they are one unitary filter element.

In embodiments in which the filter cartridge <NUM> is removably mounted in the opening <NUM> of the second end cap <NUM>, there can be a seal member <NUM> radially formed between the sidewall <NUM> of the media pack <NUM> and a radial inner portion of the second end cap <NUM>. While the seal member <NUM> shown in the drawings forms an inwardly directed radial seal, many other types of seals can be formed including a pinch seal or an axial seal.

Preferably, to avoid blocking flow through the pleated media <NUM> (i.e., masking), there will be a minimum and/or controlled distance <NUM> (<FIG>) between the outer periphery of the cartridge <NUM> and inner wall of the pleats <NUM> along the interior <NUM>. For example, the distance <NUM> can be: at least <NUM>; no greater <NUM>% of the diameter of the opening <NUM>; typically less than <NUM>; and typically in a range of <NUM>-<NUM>.

The media pack <NUM> is preferably a coiled media pack, but in other embodiments, the media pack <NUM> can be stacked, as described with respect to <FIG> above. In this embodiment, the media pack <NUM> has a cross-sectional shape that matches the cross-sectional shape of the openings <NUM>, <NUM> of the end caps <NUM>, <NUM>. In this example, the shape is round. In other embodiments, the media pack can be other shapes including, for example: non-round, obround, oval, racetrack-shaped, kidney-shaped, conical, frusto-conical, trapezoidal, regular or irregular polygon, banana-shaped; a sector of an annulus with rounded ends; or a segment of a circle.

The media pack <NUM> extends from the second end cap <NUM> into the interior volume <NUM> and toward the first end cap <NUM> along an extension less than half of a distance between the first <NUM> and second end caps <NUM>. In some embodiments, it extends less than one-third of the distance between the first <NUM> and second <NUM> end caps. Alternatives are possible including the media pack <NUM> extending from the second end cap <NUM> into the interior volume <NUM> and toward the first end cap <NUM> along an extension greater than <NUM>%, or greater than <NUM>%, or greater than <NUM>%, or greater than <NUM>%, or greater than <NUM>% of a distance between the first <NUM> and second end caps <NUM>.

The filter cartridge <NUM> allows for flow of unfiltered fluid, such as air, through the first flow face <NUM>. The media pack <NUM> removes particulate, and filtered fluid the flows through the second flow face <NUM> to reach the interior volume <NUM> of the filter element <NUM>. Likewise, unfiltered fluid flows through the filter media <NUM> and into the interior volume <NUM>, joining the filtered fluid that passed through the filter cartridge <NUM>. From there, the filtered fluid flows through the aperture <NUM>.

In general, advantages are achieved with the filter arrangement <NUM> over the prior art. For example, the filter cartridge <NUM> helps to add life and more media to both the filter arrangement <NUM> without creating a larger footprint. In addition, having two different media types (e.g., pleated media <NUM> and media <NUM>) leads to advantages including being able to filter different particle sizes. The two different media types can be helpful since they will often having different clogging behavior in high or low humid conditions. For example, in changing humidity periods, the different media types (e.g., pleated <NUM> and media <NUM>) can show different loading behavior over time, which can lower the overall pressure drop by providing more media and two options for the fluid (air) to pass.

An alternative embodiment for the filter arrangement is shown in <FIG> at <NUM>'. The filter arrangement <NUM>' can be the same as the filter arrangement <NUM>, described above, except that there is an alternative embodiment of the second end cap <NUM>'.

In <FIG>, the opening <NUM>' in the second end cap <NUM>' is off-center. The filter cartridge <NUM>' is oriented in the opening <NUM>', either removably or permanently. A seal member <NUM>' is around the periphery of the filter cartridge <NUM>'. The seal member <NUM>' can project from a remaining portion of the end cap <NUM>', as can be seen in <FIG>.

The media pack <NUM>' can be any of the various types described above in section II of this disclosure. For example, the media pack <NUM>' can be straight-through flow media, such as fluted media, pleated media, Z-media, membrane, depth media, foam media, and any variation as described in Section II. The outer perimeter shape of the filter cartridge <NUM>' is non-round. In the example shown in <FIG>, the shape can include: a sector of an annulus with rounded ends; a segment of a circle; a kidney; or a banana.

In some implementations, the filter cartridge <NUM>' can be operably installed in a filter housing, in which a portion of the housing has an opening that is sized to receive the axially projecting seal member <NUM>'. The seal member <NUM>', in the embodiment shown, is an outwardly extending radial seal to form a seal between the filter cartridge <NUM>' and the opening <NUM>' in the end cap <NUM>'. The seal member <NUM>', since it projects axially from the end cap <NUM>' is positioned to form a radially seal with a similar shaped opening (e.g., a sector of an annulus with rounded ends; a segment of a circle; a kidney; or a banana) in a portion of a filter housing, such as either the housing body or a housing cover. Alternative seals are possible including a radially inwardly extending radial seal, axial seal, pinch seal, or a combination. The media pack <NUM>' operates to filter any fluid flowing through the opening in the housing.

In further examples, the filter cartridge <NUM>' is non-removably a part of the end cap <NUM>'. The seal member <NUM>' projects axially from the end cap <NUM>' and is positioned to form a removable seal with a similar shaped opening (e.g., a sector of an annulus with rounded ends; a segment of a circle; a kidney; or a banana) in a portion of a filter housing, such as either the housing body or a housing cover. The removable seal can be a radial seal (inward or outward directed), axial seal, or pinch seal.

In further examples, the filter cartridge <NUM>' is removably inserted into the end cap <NUM>'. There can be a first seal member, in the form of seal member <NUM>', between the filter cartridge <NUM>' and the end cap <NUM>', and a second seal member in the form of seal member <NUM> (<FIG>) projecting axially from the end cap <NUM>', which is positioned to form a removable seal over an opening, which could be many shapes (e.g., a sector of an annulus with rounded ends; a segment of a circle; a kidney; or a banana) in a portion of a filter housing, such as either the housing body or a housing cover. The first seal member <NUM>' between the cartridge <NUM>' and the end cap <NUM>' can be a radial seal, while the second seal member <NUM> with the housing part can be an axial seal. The second seal member <NUM> can have a periphery of many shapes, such as rectangular as shown in <FIG>. In an alternative, the filter cartridge <NUM>' may be a non-removable part of the end cap <NUM>'.

Claim 1:
A filter element (<NUM>) comprising:
(a) a tubular section of filter media (<NUM>); and
(b) a first end cap (<NUM>) secured to the filter media (<NUM>);
(i) the first end cap (<NUM>) having a seal arrangement (<NUM>) along an inner radial surface (<NUM>);
(ii) the seal arrangement (<NUM>) including a seal member (<NUM>) having an inwardly radially directed seal surface (<NUM>) and a thickness that varies along the inwardly radially directed seal surface (<NUM>), the thickness of the seal member surface varying in a radial direction along the inwardly radially directed seal surface (<NUM>); wherein the radially directed seal surface (<NUM>) comprises a plurality of outwardly projecting and axially extending portions (<NUM>) and a plurality of inwardly projecting and axially extending portions (<NUM>) the inwardly radially directed seal surface positioned to form a seal against a tube sheet seal member; and
(c) a second end cap (<NUM>) secured to the filter media (<NUM>) opposite of the first end cap (<NUM>);
(i) the second end cap (<NUM>) being closed except for a seal-receiving opening (<NUM>) in the center of the second end cap (<NUM>); the seal-receiving opening (<NUM>) having an outer diameter (<NUM>) less than <NUM>% of an outer diameter (<NUM>) of the second end cap (<NUM>).