Patent Description:
Filter elements are used to filter fluid such as air to prevent damage or reduced functionality of downstream systems. Typically, the filter elements are configured to be a replacement part such that when they become clogged or their useful life is otherwise spent, they can be replaced.

One particular type of filter element utilizes a plurality of panels of filter media operably mounted to a frame. The panels of filter media are operably sealed relative to each other on three sides to form a cavity that is open on a single side. The present invention relates to improvements over the state of the art for this type of filter element.

The following documents may provide technical background to the present disclosure: <CIT>; <CIT>; <CIT>; <CIT>; and <CIT>.

A filter element is provided as defined in appended claim <NUM>. Optional features are as defined in the appended dependent claims.

In one embodiment, the first portion of the base frame is a first outward extending flange that is received in the first end cap structure and the second portion of the base frame is a second outward extending flange that is received in the second end cap structure. The first and second flanges are on opposite sides of the first opening and extend outward away from one another.

In one embodiment, the support frame defines first, second, third, and fourth sides with, the first and second sides offset from one another and extending between the third and fourth sides. The first side of the support frame is positioned adjacent the first sides of the first and second filter media panels. The second side of the support frame is positioned adjacent the second sides of the first and second filter media panels. The third side of the support frame is positioned adjacent the third sides of the first and second filter media panels. The fourth side of the support frame is positioned adjacent the fourth sides of the first and second filter media panels.

In one embodiment, the third side of the support frame is captured in the first end cap structure and the fourth side of the support frame is captured in the second end cap structure.

In one embodiment, the filter element includes a second side support structure adjacent the second sides of the first and second media panels and the support frame. The second side support structure extends between first and second ends. The first end is captured in the first end cap structure and the second end is captured in the second end cap structure.

In one embodiment, the first and second filter media panels are pleated media panels. At least one pleat of the first and second filter media panels is pinched between the second side of the support frame and the second side support structure.

In one embodiment, a seal material is interposed between the second side of the support frame and the second side support structure. The seal material seals the second side of the first and second filter media panels to at least one of the second side of the support frame and the second side support structure.

In one embodiment, the second side support structure includes a handle member.

In one embodiment, the second side of the support frame overlaps, at least in part, the second sides of the first and second filter media panels.

In one embodiment, a housing seal is carried by the base frame for operably sealing the filter element to a housing structure.

The first and second end cap structures are each composite structures including a cupped end cap and adhesive within the cupped end cap. At least the adhesive captures the corresponding side of the support frame, portion of the base frame and sealing the corresponding sides of the first and second filter media panel.

In one embodiment, the first and second end cap structures are formed from rigid urethane. The rigid urethane captures the corresponding side of the support frame, portion of the base frame and sealing the corresponding sides of the first and second filter media panel.

In one embodiment, the first sides of the first and second filter media panels are sealingly attached to the base frame.

In one embodiment, the first side of the support frame defines a second opening in fluid communication with the cavity between the first and second filter media panels.

In one embodiment, the first, second, third, and fourth sides of the support frame bound first and second flow openings. The first flow opening being adjacent the first filter media panel and the second flow opening being adjacent the second filter media panel.

In one embodiment, the first and second filter media panels define interior faces. The interior faces of the first and second filter media panels generally facing each other.

In one embodiment, the support frame and base frame maintain the interior faces of the first and second filter media panels in a non-parallel orientation with the first sides of the first and second panels spaced part from one another at a greater distance than the second sides of the first and second panels such that the cavity is generally wedge shaped.

In one embodiment, each of the first and second portions of the base frame defines first and second tapered locating surfaces. The first side of the first filter media panel is supported on the first tapered locating surfaces and the first side of the second filter media panel supported on the second tapered locating surfaces.

In one embodiment, the first tapered locating surfaces are substantially parallel to the first side of the first filter media panel and the second tapered locating surfaces are substantially parallel to the first side of the second filter media panel.

In one embodiment, the first tapered locating surfaces are substantially perpendicular to the interior face of the first filter media panel and the second tapered locating surfaces are substantially perpendicular to the interior face of the second filter media panel.

In one embodiment, the first and second filter media panels are pleated media panels formed from a sheet of filter media having a plurality of panels formed by alternating folds, the folds extending longitudinally between the third and fourth sides of the filter media panels, the first side of the filter media panels being adjacent the base frame and the second side of the filter media panel being spaced apart from the first side and the base frame, the third and fourth sides of the filter media panels extending between the first and second sides.

<FIG> is a perspective illustration of an embodiment of a filter element <NUM> for filtering air. The filter element <NUM> will filter fluid such as air as it is passed therethrough to remove particulates and impurities carried by the fluid being filtered.

The filter element <NUM> includes a pair of filter media panels <NUM>, <NUM> through which the fluid passes that performs the filtering. The filter media panels <NUM>, <NUM> may be formed from various different types of filter media and in one embodiment the filter media panels <NUM>, <NUM> are provided by pleated filter media. The pleated filter media is formed by a plurality of adjacent panels connected to one another at a plurality of alternating folds in an accordion fashion.

With reference to <FIG>, the filter media panels <NUM>, <NUM> are mounted to a multi-component holding assembly and oriented such that the filter media panels extend at an angle α relative to one another. Due at least to the angle α between the filter media panels <NUM>, <NUM>, the filter media panels <NUM>, <NUM> form a cavity <NUM> therebetween.

With reference to <FIG>, the filter media panels <NUM>, <NUM> each have a generally rectangular periphery including a first side <NUM>, <NUM>, a second side <NUM>, <NUM>, a third side <NUM>, <NUM> and a fourth side <NUM>, <NUM>. The filter media panels <NUM>, <NUM> also include inner faces <NUM>, <NUM> that face one another when assembled and outer faces <NUM>, <NUM> that face away from one another when assembled. The faces are bounded by the first <NUM>, <NUM>, second <NUM>, <NUM>, third <NUM>, <NUM> and fourth <NUM>, <NUM> sides. The inner and outer faces <NUM>, <NUM>, <NUM>, <NUM> may be considered flow faces as the primary fluid flow through the filter media panels <NUM>, <NUM> is through these faces <NUM>, <NUM>, <NUM>, <NUM>.

The multi-component holding assembly <NUM> is configured to mount the filter media panels <NUM>, <NUM> in the desired orientation. The multi-component holding assembly <NUM> of the illustrated embodiment generally includes a support frame <NUM>, a base frame <NUM>, first and second end cap structures <NUM>, <NUM> and a second side support structure <NUM>.

The support frame <NUM> generally maintains the first and second filter media panels in the desired spaced orientation such that cavity <NUM> (<FIG>) is formed. In the illustrated embodiment, the spaced orientation is angled at angle α as indicated previously. In this configuration, the interior faces <NUM>, <NUM> are maintained in a non-parallel, non-perpendicular orientation with the first sides <NUM>, <NUM> of the first and second filter media panels <NUM>, <NUM> spaced apart from one another a greater distance than the second sides <NUM>, <NUM>. This orientation gives cavity <NUM> a wedge shape.

With additional reference to <FIG>, the support frame <NUM> generally defines first, second, third and fourth sides <NUM>, <NUM>, <NUM>, <NUM>. The first and second sides <NUM>, <NUM> are generally offset from one another and extend between the third and fourth sides <NUM>, <NUM>. With additional reference to <FIG> (which has filter media panel <NUM> and end cap structure <NUM> removed for clarity, in the assembled state, the first side <NUM> of the support frame <NUM> is adjacent the first sides <NUM>, <NUM> of the filter media panels <NUM>, <NUM>, the second side <NUM> of the support frame <NUM> is adjacent the second sides <NUM>, <NUM> of the filter media panels <NUM>, <NUM>, the third side <NUM> of the support frame <NUM> is adjacent the third sides <NUM>, <NUM> of the filter media panels <NUM>, <NUM> and the fourth side <NUM> of the support frame <NUM> is adjacent the fourth sides <NUM>, <NUM> of the filter media panels <NUM>, <NUM>.

In this embodiment, the first side <NUM> of the support frame <NUM> defines a first side opening <NUM> through which fluid flows during the filtering process to exit cavity <NUM> between the filter media panels <NUM>, <NUM>. The first, second, third and fourth sides <NUM>, <NUM>, <NUM>, <NUM> of the support frame <NUM> also bound first and second flow openings <NUM>, <NUM> that are adjacent to filter media panels <NUM>, <NUM>, respectively, when assembled, through which fluid flows prior to or after passing through corresponding filter media panels <NUM>, <NUM> depending on if the filter element <NUM> is configured for inside-out or outside-in fluid flow.

The support frame <NUM>, in the illustrated embodiment, includes an overlap portion <NUM> that has opposite first and second flange portions <NUM>, <NUM> that extend laterally outward in opposite directions. The first and second flange portions <NUM>, <NUM> extend laterally outward such that the overlap portion <NUM> overlaps at least a portion of each of the second sides <NUM>, <NUM> of the first and second filter media panels <NUM>, <NUM>. The bottom surfaces of the flange portions <NUM>, <NUM> adjacent the filter media panels <NUM>, <NUM> may be angled relative to a central bisecting plane <NUM> of the support frame <NUM> at an angle equivalent to angle α/<NUM> plus ninety degrees.

The support frame <NUM> is operably connected to the base frame <NUM>. The support frame <NUM> in the illustrated embodiment includes snap structures <NUM> that snap engage corresponding snap structures <NUM> of the base frame <NUM>. In the illustrated embodiment, snap structures <NUM> are provided by apertures formed in a portion of the support frame <NUM> proximate the intersection of the first side <NUM> with the third and fourth sides <NUM>, <NUM>. Snap structures <NUM> are outward extending projections sized and positioned to extend into the apertures provided by snap structures <NUM>. The projections provided by the snap structures <NUM> may have tapers or ramps to facilitate connecting the support frame <NUM> to the base frame <NUM>. Engagement of the snap structures <NUM> with snap structures <NUM> is illustrated in <FIG>.

In alternative embodiments, the snap structures could be reversed and other cooperating snap structures are contemplated. The snap engagement facilitates initial assembly of the multi-component holding assembly <NUM> prior to mounting of the filter media panels <NUM>, <NUM>.

A second side support structure <NUM> is operably connected to the second side <NUM> of the support frame <NUM>. The second side support structure <NUM> includes connection elements <NUM> that extend into recesses <NUM> (also referred to as receptacles) formed in the support frame <NUM>. Preferably, the fit between the connection elements <NUM> and the recesses provides a snap engagement. The second side support structure <NUM> extends between opposed first and second ends <NUM>, <NUM> with a connection element <NUM> at each end. The cooperating catch arrangement of the connection elements <NUM> and recesses <NUM> may include catches or undercuts to form an improved connection between the support frame <NUM> and the second side support structure <NUM> such as illustrated in <FIG>.

The second side support structure <NUM> overlaps the flange portions <NUM>, <NUM> of the support frame <NUM>. With additional reference to <FIG>, in one embodiment where the filter media panels <NUM>, <NUM> are formed from pleated media with the folds <NUM> (see <FIG>) of the pleated media extending perpendicularly between the third and fourth sides <NUM>, <NUM>, <NUM>, <NUM> of the filter media panels, at least one panel <NUM> of each filter media panel <NUM>, <NUM> is pinched between a top surface of the corresponding flange portion <NUM>, <NUM> and a bottom surface of the second side support structure <NUM>. A seal material <NUM>, such as a glue bead or adhesive is applied to seal the portion of the pleated media between the second side support structure <NUM> and the second side <NUM>, e.g. flange portions <NUM>, <NUM>, to seal the filter media panels <NUM>, <NUM> along the second sides <NUM>, <NUM> thereof. The seal material <NUM> will also help secure the second side support structure to the second side <NUM> of the support frame <NUM>. The support frame <NUM> defines a second side stop <NUM> that extends between the third and fourth sides <NUM>, <NUM> against which the inner faces <NUM>, <NUM> of the first and second filter media panels <NUM>, <NUM> proximate the second sides <NUM>, <NUM> thereof rest when in an assembled state.

The second side support structure <NUM> (also referred to as a handle member) includes a handle <NUM> including a gripping portion configured to be grasped by a user to remove the filter element <NUM> at maintenance intervals. The handle <NUM> is located axially between the opposed first and second ends <NUM>, <NUM> of the second side support structure <NUM>.

With reference to <FIG>, in the illustrated embodiment, the third and fourth sides <NUM>, <NUM> are formed from frame segments including a pair of converging elongated segments <NUM>, <NUM> and a cross-brace segment <NUM> that extends between the elongated segments <NUM>, <NUM>. The pair of converging elongated segments <NUM>, <NUM> for the third and fourth sides <NUM>, <NUM> converge proximate the second side <NUM>. The snap structures <NUM> are formed as part of the cross brace segments <NUM>.

The first side <NUM> of the support frame is defined by the cross-brace segments <NUM> and a pair of first side elongated segments <NUM>, <NUM> that extend generally parallel to one another between the third and fourth sides <NUM>, <NUM> in a spaced apart relation.

The support frame opening is defined by the cross-brace segments <NUM> and the pair of first side elongated segments <NUM>, <NUM>.

When assembled, the inner faces <NUM>, <NUM> of the first and second filter media panels may rest against the elongated segments <NUM>, <NUM> and <NUM>, <NUM>.

The base frame <NUM> cooperates with the support frame <NUM> to support the filter media panels <NUM>, <NUM>. The base frame <NUM> supports a first side <NUM>, <NUM> of the filter media panels <NUM>, <NUM>.

With reference to <FIG> and primary reference to <FIG>, the base frame <NUM> defines a base frame opening <NUM> through which dirty fluid enters or clean fluid exits the filter element based on the flow direction of the fluid through the filter element. More than one base frame opening may be provided if multiple sets of filter media panels are mounted to a single base frame <NUM>.

In the illustrated embodiment, the base frame <NUM> includes a pair of opposed captured portions in the form of first and second outward extending flanges <NUM>, <NUM>. The outward extending flanges <NUM>, <NUM> extend away from one another on opposite sides of the base frame opening <NUM> and form under cuts <NUM>, <NUM>.

Locating surfaces <NUM>, <NUM>, <NUM>, <NUM> of the outward extending flanges <NUM>, <NUM> support opposed ends of the first sides <NUM>, <NUM> of the filter media panels <NUM>, <NUM>. In the illustrated embodiment, the locating surfaces <NUM>, <NUM>, <NUM>, <NUM> are tapered relative to central plane <NUM> at angle of <NUM> minus angle α/<NUM>. As such, the locating surfaces are generally perpendicular to the planes <NUM>, <NUM> (see <FIG>) defined by the first, second, third and fourth sides <NUM>, <NUM>, <NUM> , <NUM> of the support frame <NUM> against which the first and second filter media panels <NUM>, <NUM> rest when assembled. Locating surfaces <NUM>, <NUM> that support the first filter media panel <NUM> are generally parallel to flange portion <NUM> of the support frame <NUM> as well as the first side <NUM> of the filter media panel <NUM> while locating surfaces <NUM>, <NUM> support the first side <NUM> of filter media panel <NUM> and are general parallel to flange portion <NUM> of the support frame <NUM> as well as the first side <NUM> of filter media panel <NUM>. The tapered locating surfaces are generally perpendicular to the inner and outer faces <NUM>, <NUM>, <NUM>, <NUM> of the filter media panels <NUM>, <NUM>. Locating surfaces <NUM>, <NUM> of the first flange <NUM> extend at a non-parallel non-perpendicular angle relative to one another as well as bisecting central plane <NUM>. Locating surfaces <NUM>, <NUM> of the first flange <NUM> extend at a non-parallel non-perpendicular angle relative to one another as well as bisecting central plane <NUM>.

Flanges <NUM>, <NUM> each define a corresponding elevated segment <NUM>, <NUM> positioned between corresponding tapered locating surfaces <NUM>, <NUM> and <NUM>, <NUM>. The elevated segments <NUM>, <NUM> define snap structures <NUM> that cooperate with snap structures <NUM> as described above. The elevated segments <NUM>, <NUM> are straddled by segments <NUM>, <NUM> when assembled to assist in locating the support frame <NUM> relative to the base frame <NUM>.

The base frame <NUM> includes support members <NUM> that have tapered surfaces <NUM>, <NUM> similar to tapered locating surfaces <NUM>, <NUM>, <NUM>, <NUM> and that facilitate support of the first sides <NUM>, <NUM> of the filter media panels <NUM>, <NUM> as well as elevated projections <NUM> (also referred to as tabs) for locating the elongated segments <NUM>, <NUM>. The support members <NUM> extend across base frame opening <NUM> between parallel extending side member portions <NUM>, <NUM>.

The base frame <NUM> carries a sealing gasket <NUM> used to seal the filter element <NUM> to a filter housing (not shown). The sealing gasket <NUM> in the illustrated embodiment is a continuous piece of D-style rope stock. The sealing gasket <NUM> is carried in an annular groove <NUM> that circumscribes the base frame <NUM>. In the illustrated embodiment, the sealing gasket <NUM> defines a radial seal. However, other embodiments could define an axial seal.

The first and second end cap structures <NUM>, <NUM> assist in operably sealing the filter media panels <NUM>, <NUM> to the support frame <NUM> and/or base frame <NUM> to prevent fluid from bypassing the filter media panels <NUM>, <NUM>.

The first end cap structure <NUM> operably seals the third sides <NUM>, <NUM> of the filter media panels <NUM>, <NUM> and the second end cap structure <NUM> operably seals the fourth sides <NUM>, <NUM>.

The first outward extending flange <NUM> of the base frame <NUM> is captured in the first end cap structure <NUM> while the second outward extending flange <NUM> of the base frame <NUM> is captured in the second end cap structure <NUM>. Not only are the first and second outward extending flanges <NUM>, <NUM> captured by the first and second end cap structures <NUM>, <NUM>, but the third side <NUM> of the support frame <NUM> is captures by the first end cap structure <NUM> while the fourth side <NUM> of the support frame <NUM> is captured by the second end cap structure <NUM>.

In an embodiment, the first and second end cap structures <NUM>, <NUM> are composite structures with each including a cupped end cap <NUM>, <NUM> and adhesive within the cupped end cap <NUM>, <NUM>. The cupped end caps <NUM>, <NUM> form wells for holding the adhesive. The adhesive may be a foamed urethane or known potting material other materials include hot melt, plastisol, epoxy, non-foamed urethane, etc. The adhesive of the first end cap structure <NUM> captures the third sides <NUM>, <NUM> of the filter media panels <NUM>, <NUM>, the first outward extending flange <NUM>, the third side <NUM> of the support frame <NUM> and the first end <NUM> of the second side support structure <NUM>. The adhesive of the second end cap structure <NUM> captures the fourth sides <NUM>, <NUM> of the filter media panels <NUM>, <NUM>, the second outward extending flange <NUM>, the fourth side <NUM> of the support frame <NUM> and the second end <NUM> of the second side support structure <NUM>.

The cupped end caps <NUM>, <NUM> also each include outward extending mounting flanges <NUM>, <NUM> for assisting in mounting the filter element <NUM> in a filter housing (not shown).

In addition to the adhesive of the end cap structures <NUM>, <NUM>, sealant beads may be applied between the first sides <NUM>, <NUM> of the filter media panels <NUM>, <NUM> and the base frame <NUM> to sealingly secure the filter media panels <NUM>, <NUM> to the base frame <NUM>. To further support the filter media panels <NUM>, <NUM>, adhesive may be applied to the tapered surfaces <NUM>, <NUM> of the support members <NUM> as well as to the top surfaces of side members <NUM>, <NUM>. Further yet, adhesive is applied to the second sides <NUM>, <NUM> of the filter media panels <NUM>, <NUM> and the second side <NUM> of the support frame <NUM> as described above.

In <FIG>, an optional support screens <NUM> are illustrated that will be positioned between the first and second filter media panels <NUM>, <NUM> and the support frame <NUM> and the base frame <NUM> as will be described in more detail with regard to the embodiment of <FIG> described below. The support screens <NUM> are formed from an expanded metal to form the through apertures and include embossed rib structures <NUM>. The rib structures <NUM> are pressed into the support screens <NUM> to provide increased support for the filter media panels <NUM>, <NUM>. While illustrated as being horizontal rib structures <NUM> that extend longitudinally between the third and fourth sides <NUM>, <NUM>, <NUM>, <NUM> of the filter media panels <NUM>, <NUM> when assembled, the rib structures <NUM> could have other orientations and shapes. For instance, they could extend vertically, e.g. between first and second sides <NUM>, <NUM>, <NUM>, <NUM> or could be diagonal or form an X-shape. Preferably, the rib structures <NUM> extend inward and away from the corresponding media panels <NUM>, <NUM> so that the rib structures <NUM> do not interfere with mounting or locating of the filter media panels <NUM>, <NUM>.

This embodiment is also illustrated with optional pleat stabilizers mounted on the inner and outer faces of the filter media panels. The pleat stabilizers may be in the form of molded components mounted to the filter media panels or could be hot melt or urethane beads applied to the filter media panels in a direction extending generally transverse to the edges/tips of the pleats when pleated media is used.

The features of the aforementioned support screens <NUM> and pleat stabilizers can be equally applied to all embodiments herein, where appropriate and not directly contradicted.

<FIG> illustrates a further embodiment of a filter element <NUM> according to the teachings of the present invention. This embodiment is substantially similar to the prior embodiment and only the primary differences will be described. Where not contradicted by context, the features of this embodiment may be used with the structure of the prior embodiment. One of the filter media panels and end cap structures has been removed for ease of understanding.

This filter element <NUM> is generally designed for an outside-in flow. As such, fluid will flow through the outer faces <NUM> of the filter media panels <NUM> (only one is shown) first and then exit the filter element <NUM> through base from opening <NUM> formed in the bottom of the base frame <NUM>.

To provide improved support of the filter media panels <NUM>, first and second support screens <NUM> are provided. Only one of the support screens <NUM> is readily visible. This support screen <NUM> would support the filter media panel that has been removed. However, a similar support screen <NUM> supports filter media panel <NUM> that is illustrated.

The support screens <NUM> are positioned between the support frame <NUM> and base frame <NUM> and the filter media panels <NUM>. The support frame <NUM> and base frame <NUM> support the support screens <NUM>. In the illustrated embodiment, the support screens <NUM> are generally L-shaped having a first side portion <NUM> and an inner face portion <NUM>. The first side portion <NUM> is positioned adjacent the first sides <NUM> of the filter media panels <NUM> as well as the outward extending flanges <NUM>, <NUM> and support members <NUM>. The inner face portion <NUM> is positioned adjacent the inner faces <NUM> of the filter media panels <NUM>.

In some embodiments, the first side portion <NUM> and inner face portion <NUM> of the support screens are formed from a single piece of material bent to correspond to the L-shape formed by the connected support frame <NUM> and base frame <NUM>. In alternative embodiments, the first side portion <NUM> and inner face portion <NUM> may be formed from separate pieces of screen. Preferably, the support screens are formed from embossed expanded screen material.

With additional reference to <FIG>, this embodiment also utilizes pleat stabilizers <NUM> when the filter media panels are formed from pleated filter media. The pleat stabilizers <NUM> provide support to the filter media due to a pressure drop across the filter media panels. The pleat stabilizers <NUM> may also maintain a desired spacing of the adjacent pleats.

While the end cap structures of the prior embodiments are described as multi-component end caps, other embodiments may utilize one-piece end caps. For instance, the end cap could be formed from a single piece of rigid urethane that is formed around the various components that are to be captured by the end cap structures discussed previously.

<FIG> illustrates a further embodiment of a filter element <NUM>. This embodiment is similar to and can include substantially all of the features of the prior embodiments. However, this embodiment utilizes two banks of filter media panels 502A, 504A and 502B, 504B mounted to a single base frame <NUM>.

<FIG> is a partial perspective illustration of a further embodiment of a filter element <NUM>'. This embodiment is similar to and can include substantially all of the features of the prior embodiments. The filter element <NUM>' has an alternative handle <NUM>' having first and second curved portions <NUM>, <NUM>. The filter element <NUM>' has pleat stabilizers <NUM>' extending the entire length of the filter media panels <NUM>,<NUM>. In addition, the filter element <NUM>' has intermediate cross-braces <NUM> that extend between the converging elongated segments <NUM>, <NUM> that provide additional structural support to the support frame <NUM>. It will be readily understood that the handle <NUM>', pleat stabilizers <NUM>' and cross-braces <NUM> can be used individually or in combination with any of the embodiments disclosed herein.

Claim 1:
A filter element (<NUM>) comprising:
first and second filter media panels (<NUM>, <NUM>), each filter media panel defining a first (<NUM>, <NUM>), a second (<NUM>, <NUM>), a third (<NUM>, <NUM>) and a fourth (<NUM>, <NUM>) side, for each filter media panel, the first and second sides are offset from one another and extend between the third and fourth sides which are offset from one another;
a support frame (<NUM>) maintaining the first and second filter media panels in a generally spaced orientation forming a cavity (<NUM>) therebetween;
a base frame (<NUM>) defining a first opening (<NUM>) in fluid communication with the cavity; and
first and second end cap structures (<NUM>, <NUM>), the first end cap structure operably sealing the third side of the first and second filter media panels and the second end cap structure operably sealing the fourth side of the first and second filter media panels, the base frame having a first portion (<NUM>) captured in the first end cap structure and a second portion (<NUM>) captured in the second end cap structure,
wherein the first and second end cap structures (<NUM>, <NUM>) are each composite structures including a cupped end cap and adhesive within the cupped end cap, at least the adhesive capturing the corresponding side (<NUM>, <NUM>) of the support frame (<NUM>) and the respective portion (<NUM>, <NUM>) of the base frame (<NUM>) and sealing the corresponding sides (<NUM>, <NUM>; <NUM>, <NUM>) of the first and second filter media panel (<NUM>, <NUM>).