Patent Description:
Filters cartridges are commonly employed to remove particulate matter flowing in a fluid stream, such as the removal of dust and other particulate from air. These filter cartridges often incorporate a filter media pack, a structural support, and seal.

A variety of filter media packs are known in the art, for example the stacked fluted filter media pack described and shown in <CIT>; and the embossed filter media pack described and shown in <CIT>.

When an air filter cartridge is used in an engine air filter assembly, it can deform under higher differential pressures. If support structure is used with the cartridge, the capacity of the cartridge can be limited, and the inlet flow face of the filter can be reduced.

The state of the art includes different examples. provides examples of a filter medium folded in a zig-zag-shape with discontinuous edge bonds.

<CIT> and <CIT>provide end caps with a flat inner surface. These involve rectangular filter media pack configurations and rectangular housing installations. For conventional end cap attachment, as in the '<NUM> and '<NUM> patents, a liquid potting material is dispensed into end caps and cured. Another approach disclosed in <CIT> involves bonding the end caps to the filter media pack utilizing a solidified heat-activated adhesive. However, this also involves end caps with a flat inner surface and used on opposite flow ends of tubular rings of pleated filter media for a different liquid filter application.

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

In view of the foregoing, it will be seen that the present disclosure provides an improved design for a filter cartridge to provide cartridge support while reducing capacity limitations or reliability concerns that can sometimes occur in the art.

The invention is described by the subject-matter of claims <NUM>-<NUM>.

As will be explained in greater detail below, a filter assembly constructed according to the teachings herein has enhanced structural support and protection of its associated filter media, and a geometry that can maximize the inlet flow face available for filtration. The subject cartridge includes a support structure on each end of the pleat pack but has a large capacity as the cartridge has a geometry that matches the cavity of the filter housing, as well as a large inlet flow face with low inlet restriction. The cartridge is also relatively easy and straightforward to manufacture and assemble, which can reduce cost.

The filter assembly includes a block or pack of filter media located between a pair of endcaps. The ends of the block/pack are non-planar, e.g., curved or multifaceted, and the end caps have a similar, and preferably a closely matching, curved or multifaceted geometry.

The filter media pack may be embodied as any type of media, e.g., fluted, pleated, etc., and as such, the invention is not limited to any particular type of media. Fluted filter media packs with alternating strips of facing and fluted media joined by inlet and outlet seal beads can be used. However, it has been found that the filter cartridge performs well and is advantageous with a deep-pleated filter media. Deep pleated media also does not require the flute seal closures associated with fluted type filter media packs.

The pleat pack is initially formed and may be located within a frame. The pleat pack can be formed from a single strip (e.g., continuous sheet) of media, which is appropriately embossed and pleated into a rectangular pleat pack, and then cut along its side edges to shape the ends. The geometry of the ends of the filter cartridge are chosen so as to substantially correspond to the inside surface of the filter housing assembly and allow fairly tight installation therein.

The pleats extend from one end of the pack to the other, in vertical, adjacent, surface-to-surface relationship to one another, with an entrance opening on an upstream side of the pleat block, and an exit opening on the opposite, downstream side. Fluid entering the entrance opening has to traverse the media strip (and be filtered) in order to pass to the exit opening.

The frame likewise has a geometry which matches the configuration of the pleat pack and supports the pleat pack in its pleated configuration. The frame has a grate with appropriate openings on its upstream and downstream sides that are sized so as not to significantly limit flow through the pack. The frame does not cover the side edges of the pleat pack. An oval mouth of the frame supports internal cross pieces across the outlet face the filter media pack for additional support, as well as a preformed gasket that can be glued directly to the mouth and provides a fluid seal against a corresponding opening in the filter housing.

The end caps are relatively thin and may have supporting rib structure, and the inside and outside curvature of the end caps preferably closely matches the curvature of the ends of the filter media pack, such that the inside surface of the end cap can be located against the ends of the pleat peaks, and the outside surface of the end caps corresponds essentially to the inside surface of the filter housing. The end cap may include short lips or edges which extend from the end cap inwardly toward a center axis of the cartridge to serve as a receptacle for the potting adhesive (urethane), as well as to locate and support the frame enclosing the filter media pack.

The cartridge provides an integrated component once the various components are affixed together. Either a rigid or liquid potting compound can be used to affix the end caps to the filter media pack, and within the frame, and to prevent fluid bypass at the ends of the pleats. If a rigid epoxy is used in the filter, integrating a snapping feature in all of the plastic components will allow for a dry assembly of the filter before it is run through an oven that will cure the potting compound. Using an epoxy to dry assemble the filter will allow the potting compound to be assembled into the endcaps as a rigid structure before the compound needs to be cured.

If a liquid potting compound is used, the endcaps preferably may have specifically designed features in the bottom of the potting reservoir to optimize the minimum quantity of potting compound needed to seal the pleat tips. There are many design styles that may be used as "baffling" for the liquid potting compound to pool in before it cures into a solid/foam structure.

Accordingly, one inventive aspect is directed toward a filter cartridge that better accommodates at least one bulged face of a filter media pack. The filter media pack has a filter media sheet, and includes an inlet face, an outlet face, opposite first and second sides, and opposite first and second ends. The sides and the ends extend transversely between the inlet face and the outlet face. In addition, the sides extend transversely between the ends, with a first end bulging outwardly or inwardly from the opposite sides to define a first bulged face. A first adhesive end wall is embedded into the first bulged face of the first end.

Another inventive aspect is directed toward a filter cartridge with end caps that accommodate a curved or multifaceted geometry of a filter media pack. The filter media pack has an inlet face, an outlet face, and ends. The ends extend transversely to the inlet and outlet faces such that each end has an external non-planar, curved or multifaceted geometry. The filter cartridge further includes a pair of end caps located against each end. Each end cap has an internal surface with a geometry closely matching the geometry of the associated filter media pack end. Further, the adhesive is disposed between the filter media pack and the end caps to secure them together.

Several structures, features, or additional aspect or processes may be used in any of the aspects above (or otherwise provided herein) such as those detailed in any of the below summary section paragraphs that may be used separately and/or in combination with each other.

In addition to the first end bulging, the second end may also bulge outwardly or inwardly from the opposite sides to define a second bulged face, with a second adhesive end wall embedded into the second bulged face of the second end.

The filter cartridge may further include first and second preform end caps, which retain the first and second adhesive end walls, respectively. Each preform end cap includes a support panel defining an arcuate or multifaceted inner support face that provides or retains one of the adhesive end walls. Alternatively, either or both of the adhesive end walls may provide the end caps, for example mold-in-place end caps.

The filter cartridge may further include a frame mounted over either the inlet face or the outlet face. The frame supports an annular gasket with a freely defined sealing surface. Further, the frame may overlap with each of the first and second preform end caps.

The frame can be bonded with the first and second preform end caps via the first and second adhesive walls, respectively. Alternatively, the frame may be snap-fitted with the first and second preform end caps.

The filter cartridge may include a permeable baffle holding adhesive of the adhesive end wall within the first and second preform end caps and integrally bonded between the first and second preform end caps and the first and second bulged faces, respectively.

In some embodiments, the first bulged face is multifaceted defining a plurality of wall segments and can define an outwardly multifaceted ridge face. In other embodiments, and more preferably, the first bulged face curves to define a curved end face. For example, preferably, the first bulged face may protrude outwardly to define an outwardly curved ridge face.

The filter cartridge preferably includes a preform end cap that retains the first adhesive end wall. Such a preform end cap may have a pair of curved (or multifaceted) ledges and a pair of linear edges extending along a border of a support panel to provide an inward facing border wall, which defines a curved (or multifaceted) potting cavity over the curved (or multifaceted) support face. In addition, one curved (or multifaceted) ledge overlaps the inlet face, and the other curved (or multifaceted) ledge overlaps the outlet face. Further, the linear edges traverse between the curved (or multifaceted) ledges of the support panel and overlap opposing sides of the filter media pack.

Such a preform end cap may also include a plurality of ribs extending from a curved (or multifaceted) outer support face of the support panel opposite the curved (or multifaceted) inner support face. The curved (or multifaceted) ledges may also have outward extended portions that, in conjunction with the linear edges, provide an outward border wall over the curved (or multifaceted) outer support face, with the ribs extending across the outward border wall to provide a rib support network.

The adhesive end walls may be accomplished with cured liquid adhesive retained by the preform end caps. For example, the liquid adhesive includes a urethane, a hotmelt, a plastisol, a thixotropic adhesive material (e.g., Sikaflex style) or an epoxy. Alternatively, the adhesive end walls may be accomplished with preformed heat activated strips that have been heat activated embedded into the filter media pack. For example, the preformed heat activated strips include at least one of epoxy, a urethane, and a hot melt that, at a temperature of at least <NUM> degrees Celsius, transforms into a liquid form suitable for embedding.

Preferably, the filter media pack is a pleat pack with the filter media sheet folded into a plurality of pleats that provide a plurality of inlet pleat tips at the inlet face and a plurality of outlet pleat tips at the outlet face. For example, the pleat pack may be variable width, with the pleats defining a width extending between opposed ends, with at least some of different pleats having a widest width and narrowest width, with the widest width greater than the narrowest width by at least <NUM> centimeter, and typically by at least <NUM> centimeters (and often more typically at least <NUM> centimeters or more).

As an alternative to a pleat pack, a fluted filter pack is provided with a stack of fluted sheets and a stack of face sheets, with alternating inlet and outlet seal strips the adjacent fluted and face sheets at the inlet face and the outlet face, respectively. And similarly, with at least some of different of the stacked fluted/face sheets having a widest width and narrowest width, with the widest width greater than the narrowest width by at least <NUM> centimeter, and typically by at least <NUM> centimeters (and often more typically at least <NUM> centimeters or more).

Preferably, the filter media pack may be configured in an oval, rounded, or racetrack configuration.

When a preform end cap is used, the perform end cap retains the first adhesive end wall and includes a support wall facing the first bulged face, with a contour matched to the first bulged face.

Further, a plurality of retainer baffles may be arranged at various locations along a support wall of the preformed end cap (the support wall facing the bulged face). The retainer baffles include at least some retainer baffles arranged away from an apex of the support wall configured to retain uncured liquid adhesive that forms the first adhesive end wall. In other words, at least some of the retainer baffles are in areas away from the bottom area where liquid adhesive would gravitationally pool during assembly and adhesive fixing.

A preform end cap can be used as the adhesive end wall. For example, a preform end cap of thermoplastic polymer material can having an inner surface directly embedded into the first bulged face of the first end. In such case, the thermoplastic polymer material provides the adhesive end wall as it can be softened and embedded for assembly.

The filter cartridge may further include a frame that supports the filter media pack, with each end cap having a lip or edge geometry that locates and supports the frame.

The filter cartridge may also have a U-shaped grate, with a perforated end panel mounted over either the outlet face or the inlet face, and with perforated side panels mounted over opposed sides. The perforated end panel and the perforated side panels are connected at corners, preferably by living hinges for example.

In a preferred filter media pack, the ends bulge outwardly from the opposite sides to define a first outwardly bulged curved (or multifaceted) face and a second outwardly bulged curved (or multifaceted) face.

The potting adhesive can form first and second adhesive end walls embedded into the first and second outwardly bulged curved (or multifaceted) faces to seal the filter media pack to unfiltered airflow through the ends.

The adhesive end walls may be dispensed in a liquid form into the end caps prior to application to the outwardly bulged curved (or multifaceted) faces, and thereafter cured to solidify.

Each preferred end cap may include a support wall facing the outwardly bulged curved (or multifaceted) face, with a curved or multifaceted contour matched to the outwardly bulged curved (or multifaceted) face. Further, the support wall may include a plurality of retainer baffles configured to retain uncured liquid adhesive.

As an alternative to liquid adhesive, the adhesive may be provided by preformed heat activated strips that have been heat activated embedded into the filter media pack. For example, the preformed heat activated strips include at least one of epoxy, a urethane, and a hot melt that, at a temperature of at least <NUM> degrees Celsius, transforms into a liquid form suitable for embedding.

Preferably, the filter cartridge further includes a frame mounted over either the inlet face or the outlet face. The frame may support an annular gasket with a freely defined sealing surface (for example, for releasable sealing with a housing). The frame may overlap with each of the end caps.

Another inventive aspect is directed toward a method for manufacturing a filter cartridge. The method involved creating a variable width filter media pack from a filter media sheet having a variable width. The created filter media pack includes an inlet face, an outlet face, opposite first and second sides, and opposite first and second ends. The sides and the ends extend transversely between the inlet face and the outlet face. Panels of the filter media sheet extend between the inlet face and the outlet face. The variable width extends between opposed ends such that different members of at least some of the panels have a different width, with a widest member of the panels providing widest width and a narrowest member of the panels providing narrowest width, with the widest width greater than the narrowest width by at least <NUM> centimeter (more typically by at least <NUM> centimeters and often by <NUM> centimeters or more), in a manner that at least the first end bulges outwardly or inwardly from the opposite sides to define a first bulged face. The method further involves embedding a first adhesive end wall into the first bulged face to seal the first bulged face.

According to the method, the second end can bulge inwardly or outwardly to define a second bulged face. Further, the method preferably embeds a second adhesive end wall into the second bulged face to seal the second bulged face.

The method preferably retains the first adhesive end wall in a preformed end cap during application to the first bulged face.

The method may dispense the first adhesive end wall into the preformed end cap in a liquid form prior to application to the first non-planar end face, and thereafter the liquid form is cured to solidify the first adhesive end wall.

As an alternative to liquid application, the method may involve placing the first adhesive end wall as preformed heat activated strips into the preform end caps. Preferably, at a temperature of at least <NUM> degrees Celsius, the preformed heat active strips are heated to a liquid form suitable for embedding. For example, after assembling the components of the filter cartridge with the preformed heat active strips over one or both opposed ends, the filter cartridge can be passed through an oven to activate the adhesive and embed into the filter media pack. However, it may be possible for lower temperature adhesives to be used, for example an adhesive that may be stored in a freezer, and that cure at room temperature, which is a contemplated embodiment.

In the method, lips of the preformed end cap may be overlapped over sides and inlet and outlet faces of the filter media pack.

In the method, frame may be arranged over the inlet face or the outlet face, and the preformed end cap and the frame are bonded with the first adhesive end wall.

In another embodiment, the method may comprise molding the first adhesive end wall to the first bulged face with a mold, and releasing mold from the first adhesive end wall such that the first adhesive end wall provides a mold-in-place end cap. For example, in an embodiment with two end caps, the method may involve molding the first and second adhesive end walls to the first and second bulged faces with at least one mold, and releasing the at least one mold from the first and second adhesive end walls such that the first and second adhesive end walls provide first and second mold-in-place end caps, respectively.

Another alternative for providing the adhesive end wall further comprises softening an inner surface of a thermoplastic polymer material of a preform end cap and applying the softened inner surface to the first bulged face to provide for the adhesive end wall via the thermoplastic polymer material of the preform end cap.

Other aspects, objectives, and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims.

<FIG> illustrates a filter cartridge <NUM> according to an embodiment of the present invention. The filter cartridge <NUM> includes a pair of end caps <NUM>, <NUM> and a filter media pack <NUM> situated between the end caps <NUM>, <NUM>. The filter media pack <NUM> has a variable width (shown in the lengthwise direction of the filter media pack shown in <FIG>) provided by different panel widths in the pleated filter media sheet <NUM> (or filter media sheets of fluted media packs when considered collectively). The variable width results in a filter media pack that has at least one non-planar end face, for example in this embodiment two curved faces at ends <NUM>, <NUM>.

While a curved design is shown in <FIG>, as shown in <FIG> the ends <NUM>, <NUM> may also be multifaceted to comprise a few clear defined flat surfaces of equal or unequal areas/sizes, (e.g., configuration of half of a hexagon or octagon for example). However, after more than <NUM> flat surfaces on the ends <NUM>, <NUM>, the surface is considered curved, as a large number of facets effectively create a curve. Therefore, an end <NUM>, <NUM> that is half of a decagon is considered curved herein, as would a configuration with even more facets.

Other alternative embodiments of the filter media pack <NUM> are oval or rounded and are intended for placement into the filter cartridge <NUM>.

Each end cap <NUM>, <NUM> has an arcuate (or multifaceted) inner support face <NUM> and matches the variable width geometry of the associated filter media pack end <NUM>, <NUM> (see <FIG>). Each end cap <NUM>, <NUM> carries adhesive <NUM> that provides adhesive end walls <NUM>, <NUM> that effectively seal closed the otherwise open ends <NUM>, <NUM> of the filter media pack <NUM>, thereby preventing unfiltered bypass of airflow. The adhesive end walls <NUM>, <NUM>, thereby force the unfiltered air flow to travel through the filter media sheet <NUM> of the filter media pack <NUM> as the air travels from the inlet face <NUM>, toward the outlet face <NUM>, preventing unfiltered air flow from travelling through the ends to the outlet face <NUM>.

The filter cartridge <NUM> preferably includes a frame <NUM> helping to support the filter media pack <NUM>, but also which can carry an annular gasket <NUM> that can serve as a housing seal to facilitate releasable sealing of the cartridge to a housing and/or duct (not shown).

The filter media pack <NUM> may be embodied as any type of media, e.g., fluted, pleated, etc., and as such, the invention is not limited to any particular type of media. However, it has been found that the filter cartridge <NUM> performs well and is advantageous with a deep-pleated filter media.

The annular gasket <NUM> has a freely defined external housing sealing surface. The gasket <NUM> may be made from any material capable of providing a gasket type seal, typically urethane (e.g., polyurethane), nitrile, or other similar rubber material. The gasket <NUM> can either be molded in place on the frame or preformed into its desired shape and is then fastened directly to the frame <NUM> either with adhesive or without the need for any additional adhesive materials (e.g., stretch/snap fit).

The end caps <NUM>, <NUM> and the frame <NUM> can be bonded together via the adhesive <NUM>, which is shown in <FIG> and cross-sections.

An alternative embodiment can have the pair of end caps <NUM>, <NUM> snap-fitted onto the frame <NUM>.

As illustrated in <FIG>, the filter cartridge <NUM> preferably includes a grate <NUM> providing additional structural support to the overall filter cartridge <NUM> and protect the filter media pack <NUM> during operation. The grate <NUM> may be U-shaped as shown. The U-shaped grate <NUM> includes a central body portion <NUM> and wings that provide opposing sides <NUM>, <NUM> on either side of the body portion <NUM> (see <FIG>).

Each side <NUM>; <NUM> is integrally connected to the body portion <NUM> via a living hinge <NUM>. This living hinge <NUM> facilitates the initial formation of the grate <NUM> as a flat component, followed by its further bending into a U-shape.

The U-shaped perforated grate <NUM> is arranged on the filter media pack <NUM> such that its body portion <NUM> is adjacent to one of the faces <NUM>, <NUM> of the filter media pack <NUM>, and its sides <NUM>, <NUM> are adjacent to the opposite sides <NUM>, <NUM> of the filter media pack <NUM>.

The frame <NUM> also preferably has a grate <NUM> with appropriate openings <NUM> on its upstream and downstream sides so as not to significantly limit flow through the filter media pack <NUM> (see <FIG>).

Each of the grates <NUM>, <NUM> include perforations <NUM>, <NUM> that can be integrally molded into the grates. These perforations <NUM>, <NUM> allow for a sufficient air flow to and from the face <NUM>; <NUM> of the filter media pack <NUM> they are adjacent to in overlapping relation.

<FIG> illustrates an exploded assembly view of the filter cartridge <NUM> shown in <FIG>, to illustrate on the component parts fit together. <FIG>, better illustrates the filter media pack <NUM> crated by the filter media sheet <NUM>, with the inlet face <NUM> and the outlet face <NUM>, as well as opposite first and second sides <NUM>, <NUM>, which may be flat, and opposite first and second ends <NUM>, <NUM>, which may be curved (or multifaceted) as discussed above.

The sides <NUM>, <NUM> and ends <NUM>, <NUM> extend transversely between the inlet face <NUM> and the outlet face <NUM>. The sides <NUM>, <NUM> also run transversely between the ends <NUM>, <NUM> such that the first end <NUM> bulges either outwardly or inwardly from the opposite sides <NUM>, <NUM> to define a first bulged face, which as shown is an outwardly curved face. Similarly, the second end <NUM> bulges either outwardly or inwardly from the opposite sides <NUM>, <NUM> to define a second bulged face, which as shown is an outwardly curved face.

The end caps <NUM>, <NUM> are preformed prior to assembly, preferably as injection molded plastic parts (e.g., nylon), although metal or other materials are possible.

Each end cap <NUM>, <NUM> defines a cavity for the reception of the adhesive.

The adhesive <NUM> bonds the filter media pack <NUM> and the U-shaped perforated grate <NUM> between the end caps <NUM>, <NUM>.

The adhesive <NUM> that may be retained by the end caps <NUM>, <NUM> forms adhesive end walls <NUM>, <NUM>, shown in <FIG> and in cross-sections taken through the end caps in <FIG>, that are embedded into the first and second curved (or multifaceted) faces of the opposite ends <NUM>, <NUM> to seal the filter media pack <NUM> against unfiltered airflow through the ends <NUM>, <NUM>. This association may include, for non-limiting example, retaining the adhesive end walls <NUM>, <NUM> in the end caps <NUM>, <NUM> during application to the bulged faces.

Alternatively, the adhesive end walls <NUM>, <NUM> may be applied in place, for example by reusable molds (configured similar to the end caps <NUM>, <NUM>), and once cured the adhesive end walls <NUM>, <NUM> can also be considered to be and thereby provide the end caps of the filter cartridge <NUM>. In this embodiment, the adhesive end walls <NUM>, <NUM> would be molded-in-place end caps without a preform. The process for this alternative embodiment is shown in <FIG>. The reusable molds would generally take the same form as the preformed end caps <NUM>, <NUM>, but would not remain with the cartridge once finished but used to create subsequent mold-in-place endcaps. For example, the molds can be configured the same or similar to preforms/end caps <NUM>, <NUM>, perhaps made out of aluminum or other reusable mold material and perhaps with multiple spaced standoffs along in the inner facing mold surface. Preferably, the preformed end caps <NUM>, <NUM> are used in conjunction with the adhesive <NUM> to form the adhesive end walls <NUM>, <NUM>, and remain on the filter cartridge (rather than as molds) to provide additional structure support and a finished appearance to the filter cartridge.

In mold embodiments, either liquid adhesive or more preferably solid heat activated solid strips of adhesive may be used as the adhesive end walls <NUM>, <NUM>. For example, heat activated strips of adhesive can be placed in such a mold and then heated to embed the strips into the opposite ends <NUM>, <NUM> of the filter media pack. For example, various embodiments of the subject invention can utilize an adhesive that is manufactured in a predetermined solid shape, e.g., a flat pliable sheet that is seated in a fixture/reusable mold (similar shape to preform end caps), and then run through an oven to soften/melt and embed into the opposite ends <NUM>, <NUM>. Once embedded the reusable molds are removed in which the adhesive end walls <NUM>, <NUM> become the end caps on opposite ends <NUM>, <NUM> of the filter cartridge <NUM>.

Utilizing a heat-activated adhesive that is solid prevents the adhesive from running down during assembly and reduces multiple passes through an oven. Because the adhesive can be thixotropic in nature, once heat activates it, the media pack is pressed into the adhesive by gravity or some other mechanical means such as weighting in a fixture. The adhesive could be non-foaming or foaming. Foaming would be activated by heating to ensure the material adequately bonds the media to the end cap. An example of a heat-activated adhesive is L&L Products L-<NUM> or L-<NUM> epoxies. Other examples and types of materials that are heat-activated adhesives that could be used as adhesive end walls <NUM>, <NUM> include urethanes and hot melts.

Additionally, a heat-activated adhesive could contain a material that is excited by an induction coil. Metal particles are such a material, but any material excited by an induction coil to produce heat could be used. As before, the adhesive could be an epoxy, urethane, or hot melt. A filter with this material is assembled and placed into a set of induction coils. These coils excite a material inside of the adhesive creating heat - similar to being placed into a convection oven. The heat activates the material and bonds the filter together in one process step. In this embodiment, the medium may require curing prior to activating the adhesive. However, it does not require ovens to cure the material.

The adhesive end walls <NUM>, <NUM> may also be provided by thermoplastic material of the preformed end caps <NUM>, <NUM>. Thermoplastic materials are polymers (e.g. nylons/polyamides, ABS, PVC, polyethylene, polypropylene, etc.. ) that can be melted and may be recast almost indefinitely. They are molten when heated and harden upon cooling. For example, the inner surfaces <NUM> of the end caps <NUM>, <NUM> can be softened (e.g. typically melted) and direct embedded into the opposite ends <NUM>, <NUM> of the pack <NUM>. Energy such as radiant heat directly applied to the inner surfaces <NUM> may be used. Another option is placing the end caps <NUM>, <NUM> on ends <NUM>, <NUM> when cool/solid and then exciting such as with ultrasonic energy that creates friction at the interface between the pack/end cap and welds the plastic material of end caps directly to the pack (typically one end cap at a time but simultaneously is also an option). In particular, heat created by radiant, ultrasonic or otherwise will soften (e.g., melt) the polymer material of the preformed end caps <NUM>, <NUM> and direct embeds and welds the material in which case the polymer material/inner portion of the end caps <NUM>, <NUM> (e.g., embedded portion) provides and thereby integrally retains the adhesive end walls <NUM>, <NUM>, which can be understood with reference to <FIG>.

Additionally, as shown in <FIG> (see also <FIG>), a bead of adhesive <NUM> is provided on the frame <NUM> (preferably situated in a channel <NUM> of the frame <NUM> between an inner blade <NUM> and an outer retainer lip <NUM>). This bead of adhesive <NUM> seals the outer most pleat <NUM> to the frame <NUM> and thereby preventing unfiltered bypass therebetween. Further, this bead of adhesive <NUM> overlaps and joins to the pool of adhesive <NUM> at the opposing end caps <NUM>, <NUM> (for example due to adhesive <NUM> carried near linear ledges <NUM>, <NUM> that are arranged to overlap with the bead of adhesive <NUM>), such that an entire periphery of the filter media pack <NUM> is sealed by adhesive (e.g., adhesive <NUM> and adhesive <NUM>) to prevent unfiltered air flow.

This bead of adhesive <NUM> can also be used to secure the U-shaped grate <NUM> to the frame <NUM>. As may be seen in <FIG> and also <FIG>, the outer opposing sides <NUM>, <NUM> of the U-shaped grate <NUM> are installed into a pocket of the outermost pleat <NUM> and together received in the channel <NUM>, and adhesive <NUM> may also optionally be applied along the outside of the opposing sides <NUM>, <NUM> of the U-shaped grate <NUM> if desired.

As will be understood, another bead of the same adhesive <NUM> (along with channel <NUM> of the frame <NUM> between an inner blade <NUM> and an outer retainer lip <NUM>) is also provided on the opposite side <NUM>, such that the view rotated <NUM> degrees in <FIG> appears the same as that shown in <FIG> and the above two paragraphs also describe the sealing of the outermost pleat <NUM> and joinder of the U-shaped grate <NUM> along the other side <NUM>.

In one embodiment shown in <FIG>, the end caps <NUM>, <NUM> are coupled to the ends <NUM>, <NUM> of the filter media pack <NUM> by liquid adhesive <NUM>. For example, the end caps <NUM>, <NUM> may be coupled with a urethane, a hotmelt, a plastisol, a thixotropic adhesive material (e.g. Sikaflex style) or an epoxy that is first applied in liquid form into the cavity of the end caps <NUM>, <NUM> and then applied to the ends <NUM>, <NUM> before curing. Once the end caps <NUM>, <NUM> are applied, the liquid adhesive <NUM> cures creating the adhesive end walls <NUM>, <NUM>.

In an alternative embodiment shown in <FIG>, the adhesive end walls <NUM>, <NUM> may include preformed heat activated strips <NUM> to connect one or more end caps <NUM>, <NUM> to the filter media pack <NUM>. Preferably, each heat activated strip <NUM> includes adhesive such as an epoxy, a urethane, or a hot melt. In this embodiment, the strips <NUM> are in solid form and in a relatively thin form that can be wrapped to the contour of the cavity of the end caps <NUM>, <NUM>.

The heat activated strips <NUM> may include other adhesives, such as polymers that have a solid state and that may at least partially transition to a fluid state sufficiently when heated.

The heat-activated strip <NUM> may optionally contain excitable material, such as metal particles, which is heated by electromagnetic induction to cause melting of the at least one heat-activated strip <NUM>.

In any of the embodiments (liquid adhesive <NUM> or preformed strips of adhesive <NUM>), as may be seen in <FIG>, the end caps <NUM>, <NUM> and the frame <NUM> can be bonded via the adhesive end walls <NUM>, <NUM>.

An additional view of filter media pack <NUM> is shown in <FIG>, where it can be seen that the filter media sheet <NUM> includes a plurality of folds. The filter media sheet <NUM> is creased at spaced intervals to form a plurality of pleat tips <NUM>, such that the pleats extend between pleat tips <NUM> at the inlet face <NUM> and pleat tips <NUM> at the outlet face <NUM>.

Further, as schematically shown in <FIG>, the pleats include first pleat panels <NUM> having embossments <NUM> and second pleat panels <NUM> that are preferably free of embossments <NUM> (or second pleat panels <NUM> can also optionally be embossed with embossments <NUM>, which may be offset from those of first pleat panels <NUM>). The embossments <NUM> are disposed at least partially between the pleat tips <NUM>. For example, suitable embossed deep pleat filter media packs <NUM> usable in the present disclosure are disclosed in <CIT>, the entire disclosure of which is hereby incorporated by reference. However, when pleat packs <NUM> are used, the width of the sheet <NUM> is varied to create bulging at one or both ends of the filter media pack <NUM> once formed.

In the schematic illustration of <FIG>, the embossments <NUM> have a width (W) of at least <NUM> millimeters and a depth (D) of at least <NUM> millimeters.

<FIG> illustrates another embodiment of a filter media pack <NUM> with a plurality of stacked filter media sheets <NUM>, including fluted media sheets <NUM> and face sheets <NUM>. The rectangular peripheries of the sheets <NUM> are aligned to form the filter media pack <NUM> and can have variable widths to create alternatives to pleat packs and use in <FIG> instead.

The stacked sheets <NUM> of such a filter media pack provide flutes such as a corrugated-type arrangement with an upper row and a lower row. As shown in the configuration, the upper flutes form flute chambers <NUM> closed at the downstream end, while upstream closed end flutes are the lower row of flute chambers <NUM>. The fluted chambers <NUM> are closed by a first end adhesive seal bead <NUM> filling a portion of the upstream end of the flute between the fluting sheet <NUM> and the lower facing sheet <NUM>. Similarly, a second end adhesive seal bead <NUM> closes the downstream end of alternating flutes <NUM>. The adhesive seal beads <NUM>, <NUM> also secure the fluted and face sheets <NUM>, <NUM> together.

Each end cap <NUM>, <NUM> may have additional features for better structural support and/or for adhesive retention. Turning now to <FIG>, each end cap <NUM>, <NUM> includes a pair of curved (or multifaceted) ledges <NUM>, <NUM> and a pair of linear edges <NUM>, <NUM> that extend along a border of a support panel. This creates the cavity for retention of the adhesive <NUM> placed therein and prevents adhesive <NUM> from spilling out of the end caps <NUM>, <NUM> (see <FIG>).

One curved ledge <NUM> overlaps the inlet face <NUM>, while the other curved ledge <NUM> overlaps the outlet face <NUM>. The linear edges <NUM>, <NUM> traverse between the curved ledges <NUM>, <NUM> of the support panel and overlap opposing sides <NUM>, <NUM> of the filter media pack <NUM>. This configuration provides an inward-facing border wall <NUM> that defines a curved (or multifaceted) cavity within each end cap <NUM>, <NUM>.

The curved ledges <NUM>, <NUM> may include outward extended portions that provide, in conjunction with the linear edges <NUM>, <NUM>, an outward border wall <NUM> over a curved (or multifaceted) outer support face <NUM>.

As illustrated in <FIG>, each end cap <NUM>, <NUM> may also include a plurality of ribs <NUM> that extend from the curved outer support face <NUM> of the support panel opposite a curved (or multifaceted) inner support face <NUM>. When the end caps <NUM>, <NUM> are assembled with the filter media pack <NUM>, the ribs <NUM> extend across the outward border walls <NUM> to provide a rib support network.

The end cap <NUM>, <NUM> may include short lips <NUM>. The lips <NUM> extend inwardly toward the filter cartridge <NUM> to provide a short edge for the end cap <NUM>, <NUM> to locate and sit atop the frame <NUM> that encloses the filter media pack <NUM>. This configuration provides support for the frame <NUM>.

Each end cap <NUM>, <NUM> may feature a plurality of angled baffles <NUM> configured to retain uncured liquid adhesive <NUM>. Turning to <FIG>, a plurality of angled baffles <NUM> is integrated into the curved inner support face <NUM> of the end caps <NUM>, <NUM>. Each angled baffle <NUM> can have a different height and spacing from its neighbors. This configuration is extremely effective at minimizing the gravitational pooling of the liquid adhesive <NUM> in the curved end cap <NUM>, <NUM>.

The angled baffles <NUM> are preferably perpendicular (vertical orientation when applying end caps) to the primary flow of the liquid adhesive <NUM> and may form an angle with the curved inner support face <NUM> of the end cap <NUM>, <NUM>. Using baffles <NUM> that are vertical during the time of dispensing a liquid adhesive (see e.g. <FIG>), however, other angles for the baffles maybe used that achieve the same function of retaining liquid adhesive away from the gravitational bottom, although not as efficiently. Preferably, the angled baffles <NUM> are between <NUM> and <NUM> millimeters long and parallel to each other as well as to the opposed sides <NUM>, <NUM> of the filter media pack <NUM>. Each angled baffle <NUM> is spaced a minimum of <NUM> millimeter apart from its neighbor (i.e. the size of the gap between adjacent baffles <NUM>) and may be separated up to <NUM> millimeters to enhance the penetration of the adhesive <NUM> into the end caps <NUM>, <NUM>. Preferably, the spacing of the angled baffles <NUM> is the thickness of the ribs <NUM> themselves (and thus the thickness/width of the baffles <NUM> is also preferably between <NUM> millimeter and <NUM> millimeters). However, the spacing could vary depending on the radius of the curve (or multifaceted surface) that the potting surface makes. Therefore, the rib thickness and rib spacing may vary as well, for example, based upon the location along the curved surface and need not be uniform, but in any event, even with the variance, the spacing and rib thickness preferably fall within the parameters discussed above.

In a further embodiment, as shown in <FIG>, a permeable baffling, for example such as a foam core pad <NUM> may be additionally inserted and attached (e.g., glued with adhesive) to the curved (or multifaceted) inner support face <NUM> of the end caps <NUM>, <NUM>.

Permeable baffling (such as the foam core pad <NUM>) preferably covers the entire curved inner support face <NUM>. The foam core pad <NUM> wicks a less viscous or non-viscous liquid urethane adhesive <NUM> (see <FIG>). Subsequently, as the filter media pack <NUM> is pressed into the end caps <NUM>, <NUM>, the urethane is squeezed out of the foam <NUM> and wicks into the filter media pack <NUM>.

The foam pad <NUM> can preferably be open cell for the liquid adhesive <NUM> to readily soak in. For example, the foam pad <NUM> can be similar to a blown insulation, where there are randomly staggered layers of fibers that stack up to create the thickness of the foam pad <NUM>. The foam pad <NUM> needs to have a low density to allow the liquid adhesive <NUM> to quickly soak into the foam, like a sponge. For example, a synthetic non-woven non-urethane foam can be used, and other examples include but are not limited to reticulated foam or polyurethane foam.

Other permeable matts of cloth, fibrous matters or other materials that hold and/or wick adhesive may also be used as such permeable baffling.

In another embodiment, as shown in <FIG>, the filter cartridge <NUM> may include the filter media pack <NUM> arranged between the end caps <NUM>, <NUM> with at least one heat activated strip <NUM> (to substitute for liquid adhesive <NUM> and provide the adhesive <NUM> in <FIG>) secured to each end cap <NUM>, <NUM>. It is understood that end cap <NUM> and end cap <NUM> can be the same and interchangeable.

Each heat activated strip <NUM> is enclosed in the end caps <NUM>, <NUM> in solid form prior to placement with the ends <NUM>, <NUM> of the filter media pack <NUM>.

Prior to heat application, the heat activated strips <NUM> may be bonded using a number of retaining means, such as a glue tab, spot welding, and gravity, to mention a few.

Once the components of the filter cartridge <NUM> are assembled into the unbonded filter media pack <NUM>, the heat activated strips <NUM> are thereby softened to cause embedding of the filter media pack ends <NUM>, <NUM> into the heat activated adhesive material of the heat activated strip <NUM>.

The heat activated strips <NUM> are heat activated sufficiently to soften and allow embedding of the filer media pack <NUM> at a temperature of at least <NUM> degrees Celsius.

While in some embodiments, one heat activated strip <NUM> may be used, a plurality of the at least one heat activated strip <NUM> may be placed between the end caps <NUM>, <NUM> of the filter cartridge <NUM>.

With reference now to <FIG>, the same illustrates a cross-sectional view of the filter cartridge <NUM> taken along the line <NUM>-<NUM> in <FIG>. The adhesive bead <NUM> is used to provide a filter media-to-frame sealing. This sealing is accomplished by lapping adhesive bead <NUM> over a small protrusion located on the interior of the frame <NUM>, contacting the filter media pack <NUM>. The filter media-to-frame adhesive bead <NUM> also provides an airtight seal for unfiltered air flow.

Additionally, as shown in <FIG>, a bonded joint is formed at the channel <NUM> of the frame <NUM>. That bonded joint is to create a seal to prevent unfiltered airflow past the sides <NUM>, <NUM> of the filter media pack <NUM>, and it is on both sides <NUM>, <NUM> of the filter media pack <NUM>. These are linear seals <NUM> on the opposing sides <NUM>, <NUM> that join with the pool of adhesive <NUM> at the opposing end caps <NUM>, <NUM>, such that an entire periphery of the filter media pack <NUM> is sealed by the adhesive <NUM> in the end caps <NUM>, <NUM> and the linear seals <NUM> on the opposite sides <NUM>, <NUM> to prevent unfiltered air flow, and thereby fluid is directed to flow from the inlet face <NUM> through the filter media <NUM> (filtering out undesired contaminants) toward the outlet face <NUM> for exiting the filter cartridge <NUM>.

<FIG> shows a cross-sectional view of the filter cartridge <NUM> taken along the line <NUM>-<NUM> in <FIG>. As can be seen, the lips <NUM> provide a short edge for the end caps <NUM>, <NUM>, and sit atop the frame <NUM> to impart structural support to the filter cartridge <NUM> as a whole.

The frame <NUM> has a grate <NUM> with appropriate perforations <NUM> and does not cover the side edges of the filter media pack <NUM>. The oval mouth of the frame <NUM> supports internal cross pieces across the outlet face <NUM> of the filter media pack <NUM> for additional support. In addition, the preformed gasket <NUM> secured to the oval mouth provides a seal against a corresponding opening in the filter housing (not shown).

The end caps <NUM>, <NUM> are relatively thin, and the inside curvature of the end caps <NUM>, <NUM> corresponds to the curvature of the ends <NUM>, <NUM> of the filter media pack <NUM>, such that the inside surface <NUM> of the end caps <NUM>, <NUM> aligns with the pleat tips <NUM>.

<FIG> shows a cross-sectional view of the filter cartridge <NUM> taken along the line <NUM>-<NUM> in <FIG>. An interior dam <NUM> is formed on the curved inner support face <NUM> of the end cap <NUM>, <NUM> that can be facilitated due to baffles <NUM>. The adhesive <NUM> suitable for fixing is poured into the dam <NUM>.

A trough may be created to minimize gravitational pooling of adhesive <NUM> and to maintain uniform distribution of adhesive <NUM> across the curved inner support face <NUM>. Retainer angled baffles <NUM> are arranged at locations away from an apex of the inner support wall <NUM>. In this manner, a barrier is provided to hold the filter media-to-end cap adhesive <NUM>. Subsequently, the end caps <NUM>, <NUM> are bonded directly to the ends <NUM>, <NUM> of the filter media pack <NUM>.

<FIG> shows a flow-chart of an embodiment of a method according to the present application. In particular, a method for manufacturing the previously described filter cartridge <NUM> is shown.

In an initial step <NUM>, a preform end cap <NUM>, <NUM> that matches the geometry of a filter media pack end <NUM>, <NUM> is provided.

In a step <NUM>, an adhesive <NUM> is deposited into the end cap <NUM>, <NUM>.

In a step <NUM>, the liquid adhesive <NUM> flows and embeds between the end cap <NUM>, <NUM> and the filter media pack end <NUM>, <NUM>.

In an alternative step <NUM>, the solid adhesive <NUM> is first heated to a liquid form suitable for embedding.

In a final step <NUM>, the adhesive <NUM> is cured.

The result of such a process is the filter cartridge <NUM> shown in <FIG> with the filter media pack <NUM> embedded into adhesive <NUM> to the end caps <NUM>, <NUM>.

Claim 1:
A filter cartridge (<NUM>), comprising:
a filter media pack (<NUM>) comprising a filter media sheet (<NUM>), the filter media pack (<NUM>) having an inlet face (<NUM>), an outlet face (<NUM>), opposite first and second sides (<NUM>, <NUM>), opposite first and second ends (<NUM>, <NUM>), the sides and the ends extending transversely between the inlet face (<NUM>) and the outlet face (<NUM>), the sides (<NUM>, <NUM>) extending transversely between the ends (<NUM>, <NUM>), wherein the first end (<NUM>) bulges outwardly or inwardly from the opposite sides (<NUM>, <NUM>) to define a first bulged face; and
first and second end caps (<NUM>, <NUM>) for respectively sealing the first and second ends (<NUM>, <NUM>) of the filter media pack (<NUM>), wherein the first end cap (<NUM>) includes a first adhesive end wall (<NUM>) embedded into the first bulged face of the first end (<NUM>).