Filter element and support structure

The current technology relates to a filter element having pleated filter media. The pleated filter media defines an elongate tubular structure having an inner passageway. The pleated filter media has outer pleat folds and inner pleat folds each extending from a first end to a second end of the elongate tubular structure. The filter element has no more than one elongate brace disposed in the inner passageway, extending between the first end and the second end. A plurality of support ribs are coupled to the elongate brace, where each support rib has a connector defining an interference-fit with the elongate brace. Each support rib partially defines the inner passageway and has an outer support surface that abuts a substantial portion of the inner pleat folds.

FIELD OF THE TECHNOLOGY

The technology disclosed herein relates generally to a filter element. More particularly, the technology disclosed herein relates to a filter element and a support structure.

SUMMARY

Some example embodiments relate to a filter element having pleated filter media. The pleated filter media defines an elongate tubular structure having an inner passageway. The pleated filter media has outer pleat folds and inner pleat folds each extending from a first end to a second end of the elongate tubular structure. The filter element has no more than one elongate brace disposed in the inner passageway, extending between the first end and the second end. A plurality of support ribs are coupled to the elongate brace, where each support rib has a connector defining an interference-fit with the elongate brace. Each support rib partially defines the inner passageway and has an outer support surface that abuts a substantial portion of the inner pleat folds.

Some example embodiments relate to a method. No more than one elongate brace is obtained. A plurality of support ribs are formed, where the support ribs each have an outer support surface. Each of the support ribs are coupled to the elongate brace via an interference fit at incremental intervals along the length of the elongate brace. Pleated filter media is wrapped around the support ribs to form an elongate tubular structure extending from a first end to a second end and defining an inner passageway.

Some example embodiments relate to a fluid filter assembly. The fluid filter assembly has a first pleated filter media defining a first tubular structure having a first inner passageway extending from a first end to a second end of the first pleated filter media to define a first media length. The first pleated filter media has outer pleat folds and inner pleat folds each extending from the first end to the second end of the first pleated filter media. A first inner support structure is disposed in the first inner passageway, where the first inner support structure has no more than one elongate brace and a first plurality of support ribs coupled to the elongate brace. The elongate brace extends between the first end and the second end of the first pleated filter media. Each of the first plurality of support ribs has a connector defining an interference-fit with the elongate brace and a first outer support surface abutting a substantial portion of the inner pleat folds of the first pleated filter media.

The fluid filter assembly also has a second pleated filter media defining a second tubular structure having a second inner passageway extending from a first end to a second end of the second pleated filter media to define a second media length. The second pleated filter media has outer pleat folds and inner pleat folds each extending from the first end to the second end of the second pleated filter media. A second inner support structure is disposed in the second inner passageway, where the second inner support structure has no more than one elongate brace and a second plurality of support ribs coupled to the elongate brace. The elongate brace extends between the second end and the second end of the second pleated filter media. Each of the second plurality of support ribs has a connector defining an interference-fit with the elongate brace and a second outer support surface abutting a substantial portion of the inner pleat folds of the second pleated filter media.

The fluid filter assembly has a first end cap coupled to the first end of the first pleated filter media and the first end of the second pleated filter media and a second end cap coupled to the second end of the first pleated filter media and the second end of the second pleated filter media. Other embodiments are described herein.

DETAILED DESCRIPTION

FIG. 1depicts an example filter element100. The filter element100generally has a pleated filter media130defining an elongate tubular structure110and an inner passageway120. An inner support structure160is disposed within the inner passageway120.

The elongate tubular structure110generally has a first end136and a second end138. A media length140is defined from the first end136to the second end138. In some embodiments, the inner passageway120extends from the first end136to the second end138of the elongate tubular structure110.

The pleated filter media130generally defines outer pleat folds144and inner pleat folds146. The outer pleat folds144are generally adjacent the environment outside of the elongate tubular structure110and the inner pleat folds146are generally adjacent the inner passageway120of the elongate tubular structure110. The inner pleat folds146and outer pleat folds144each generally extend along the media length140. In some embodiments, the outer pleat folds144and the inner pleat folds146each extend from the first end136to the second end138of the elongate tubular structure110.

In the current example, the pleated filter media130defines three corners134and three faces135. Despite having pleats, each face can be characterized as generally planar, where the term “planar” as used herein encompasses relatively flat planes and substantially curved planes. The phrase “substantially curved plane” is used herein to encompass actually curved planes but also configurations where there are a plurality of adjacent flat planes to form facets that approximate a curved plane. An example face forming a substantially curved plane will be referenced in more detail in the discussion ofFIG. 9. The three corners134and the three faces135define a generally triangular shape of the pleated filter media130in a cross section perpendicular to the length of the media, which will be described in more detail with reference toFIG. 4A. A “corner” is generally defined herein as a region of intersection of at least two faces of the pleated filter media130. The region can define an edge or a substantially curved plane, and in the current example each corner134is a substantially curved plane. The corners134of the pleated filter media130extend from the first end136to the second end138of the elongate tubular structure110.

The filter element100is generally configured for fluid filtration. In some implementations, the filter element100can be configured for liquid filtration. In some implementations, the filter element100can be configured for gas filtration. The pleated filter media130can be constructed with a variety of materials suitable for the intended use of the filter element100. The pleated filter media130can be constructed of one or more media layers of filtration material. The pleated filter media130can be manufactured from a variety of medias which can include non-woven media or fabric and membranes constructed from organic, synthetic, or a mixture of organic and synthetic medias. In some embodiments, cellulose, glass, polyester (PE), polypropylene, polytetrafluoroethylene (PTFE), or expanded PTFE (ePTFE) are utilized in the pleated filter media130. The pleated filter media130can be constructed of nanofiber, such as that created by Donaldson Company, Inc. of Bloomington, Minn. In some embodiments, the pleated filter media130can be constructed of a cellulose media having one or more layers of nanofiber. In some embodiments, the pleated filter media130comprises activated carbon. The pleated filter media130can have layers co-pleated or bonded with melt-blown carbon media. The pleated filter media130can be constructed of a self-supporting media. The pleated filter media130can include a media supported on one or both sides. A pleated filter media130can have a wire backing on one or both sides, for example.

The pleated filter media130could also include a coating for enhanced filtration, chemical resistance, electrical properties and microbial growth. Additionally, the pleated filter media130can have any number of treatments to improve its efficiency in removing particulates and for other purposes. For example, electrostatically treated media can be used. The pleated filter media130can also be treated with anti-microbial substances to prevent the growth of mold on the filters. Anti-viral or anti-mycotic agents may also be used to treat the pleated filter media130to reduce the populations of infectious agents.

The pleated filter media130is generally formed by pleating a filtration media. The pleats are generally defined between the inner pleat folds146and the outer pleat folds144. Various methods of pleating a filtration media into a pleated filter media130are contemplated. In some embodiments, the pleated filter media130is pleated using a blade pleater. The pleat height and frequency (number of pleats per unit of length) are not particularly limited. Pleat spacing is selected such that pleats are not so close as to close off effective media area under load and not so spaced as to underutilize potential effective media area. Effective pleat spacing can vary with the type of media and pleat height. In some embodiments, a substantial portion (i.e. at least 90%) of the pleats in the pleated filter media130have substantially equal pleat heights, which will be described in more detail with reference toFIG. 4A. Various cross-sectional shapes of the individual pleats are contemplated, such a triangle, rectangle, and the like. Pleated media can provide a relative increase to the filtration surface area of a filter assembly when compared to unpleated media.

As mentioned above, the filter element100can be used for a variety of fluid filtration applications. The filter element100can be configured for inside-out or outside-in fluid flow. In some implementations, the filter element100can be configured for liquid filtration. In some liquid filtration implementations, the filter element100is configured for inside-out flow. In some liquid filtration implementations, the filter element100is configured for outside-in flow. Examples of liquid filtration include water filtration, fuel filtration, and the like. In some implementations, the filter element100can be configured for gas filtration. In some gas filtration implementations, the filter element100is configured for outside-in flow. In some gas filtration implementations, the filter element100is configured for inside-out flow. Examples of gas filtration include air filtration and filtration of other gases.

The filter element100can be configured to receive end caps to direct fluid flow through the pleated filter media130. The filter element100can be configured to receive a first end cap (not shown) on the first end136. In such embodiments, the first end cap can be configured to couple to the first end136of the pleated filter media130. The first end cap can define an opening in communication with the inner passageway120. The filter element100can be configured to receive a second end cap (not shown) on the second end138. In such embodiments, the second end cap can be configured to couple to the second end138of the pleated filter media130. The second end cap can be configured to form a barrier across the inner passageway. Example end caps will be described in more detail below with reference toFIGS. 6 and 7.

The inner support structure160of the filter element100is generally a rigid structure configured to provide structural support to the pleated filter media130. In some embodiments, the inner support structure160is configured to provide a structure onto which the pleated filter media130can be disposed during manufacture. In some embodiments, the inner support structure160is configured to prevent the pleated filter media130from collapsing during fluid filtration. In various embodiments, the inner support structure160defines a shape to which the pleated filter media130conforms. The inner support structure160at least partially defines the inner passageway120. In some examples, the inner support structure160maintains the triangular cross-sectional shape of the pleated filter media130.

FIG. 2is a cutaway view of the filter element100depicted inFIG. 1. A portion of the pleated filter media130is removed to view the inner support structure160.FIG. 3is a perspective view of the inner support structure160of the filter element100with no filter media. The inner support structure160has an elongate brace162. The inner support structure160has a plurality of support ribs170coupled to the elongate brace162.

The elongate brace162is generally configured to provide structural support to the pleated filter media130and plurality of support ribs170. The elongate brace162is generally an elongate structure configured to receive each of the plurality of support ribs170to form the inner support structure160.

Inner support structures consistent with the technology disclosed herein generally have no more than one elongate brace162. The elongate brace162can have a geometry that is universal to different filter elements. By way of example, filter elements of differing configurations can incorporate elongate braces of differing or similar lengths but otherwise like geometry. The elongate brace162is disposed in the inner passageway120of the filter element100. Generally, the elongate brace162extends between the first end136and the second end138of the pleated filter media130. In some embodiments, the elongate brace162extends from the first end136towards the second end138. In some such embodiments, the elongate brace162extends from the first end136to the second end138of the pleated filter media130.

The elongate brace162can be a tube, rod, or other elongate structure. The elongate brace162can be constructed of a variety of materials. The elongate brace162can be constructed of plastics, metals, woods, ceramics, composites, and the like. The elongate brace162can be pervious or impervious to the fluid sought to be filtered. In some embodiments the elongate brace162is constructed of a mesh material, and in other embodiments the elongate brace162is constructed of a solid material. In some embodiments, the elongate brace162is constructed by forming a tubular structure from a plastic mesh material. In some embodiments, the elongate brace162is constructed by injection molding a tubular structure. In other embodiments, the elongate brace162is constructed by extruding a plastic or metal. The elongate brace162can be otherwise molded, cast, machined or manufactured.

The elongate brace162generally has a construction that provides adequate stiffness and strength to support the pleated filter media130during the manufacturing process. The elongate brace162can have a variety of cross-sectional shapes in a direction perpendicular to the length of the elongate brace162. In some embodiments, the elongate brace162has a circular cross section. The elongate brace can also have a triangular, quadrilateral, or other polygonal cross section. In some embodiments, the elongate brace can have an irregularly shaped cross section. The elongate brace162is generally characterized by a geometry with which the support ribs170of the inner support structure160can couple. For example, the circular cross section of the elongate brace162of the current example is configured to mate with the structure of each of the plurality of support ribs170.

The support ribs170are configured to provide structural support to the elongate tubular structure110of the pleated filter media130. The plurality of support ribs170generally defines and maintains the shape of the pleated filter media130. Each of the support ribs170generally has a connector172, a cross-brace176, and an outer support surface173.

The support ribs170are configured to be disposed in the inner passageway120of the pleated filter media130. The support ribs170at least partially define the inner passageway120. The support ribs170are positioned axially along the length of the elongate brace162. The plurality of support ribs170are generally positioned with a like orientation. In some embodiments, each of the plurality of support ribs170defines a like shape. In some embodiments, some or all of the plurality of support ribs170are identical. Embodiments in which the support ribs170each define a like or identical shape provide incremental support to maintain the shape of the pleated filter media130along the length of the pleated filter media130.

The support ribs170can be coupled to the elongate brace162at regular or irregular incremental intervals along the length of the elongate brace162. The interval or spacing between the support ribs170is generally such that the shape of the pleated filter media130is adequately supported during manufacturing and/or filtration. For example, the spacing of the support ribs170can be adjusted to appropriately support the pleated filter media130for a given fluid sought to be filtered, fluid flow rate, the type of pleated filter media130, and other factors. In various embodiments, the support ribs170provide a sufficiently rigid structure to form the pleated filter media130there-around during manufacturing.

The inner support structure160generally has a quantity of support ribs170suitable to provide a desired interval between support ribs170for a filter element100of a given length. In some embodiments, the inner support structure160has two or more support ribs170. In some embodiments, the plurality of support ribs170is at least a first support rib177disposed towards the first end136of the elongate tubular structure110, a second support rib178disposed towards the second end138of the elongate tubular structure110, and a third support rib179disposed between the first support rib177and the second support rib178. The number of support ribs170of the inner support structure160is not particularly limited.

The support rib170can be constructed of plastics, metals, woods, ceramics, composites, and the like. The support rib170can more particularly be constructed of polypropylene, polyvinylchloride (PVC), polyethylene, polyethylene terephthalate (PET), acrylonitrile butadiene styrene (ABS), nylon, and the like. The support rib170can be pervious or impervious to the fluid sought to be filtered. In some embodiments, the support rib170is constructed by injection molding. In other embodiments, the support rib170is constructed by extrusion. The support rib170can be otherwise molded, cast, machined or manufactured.

The outer support surface173is an outer surface of each support rib170configured structurally support the pleated filter media130. In some embodiments, the outer support surface173defines two or more corners175and particularly three corners175in examples consistent with the current embodiment. The outer support surface173is generally configured to be disposed within the inner passageway120of the pleated filter media130. In some embodiments, the outer support surface173abuts a substantial portion of the inner pleat folds146of the pleated filter media130, where the phrase “substantial portion” is defined herein as at least 90%. The pleated filter media130generally conforms to the shape of the outer support surface173. Specifically, the outer support surface173of the support rib170abuts the inner pleat folds146around each corner175.

The outer support surface173can be configured to minimally inhibit flow through the pleated filter media130. For example, in the current embodiment, each support rib170mutually defines the inner passageway120. The outer support surface173of each support rib170can be a solid portion of material. In some embodiments, the outer support surface173is a fluid impermeable region of material. In other embodiments, at least some portions of the outer support surface173can define a fluid permeable region such as a mesh structure.

The connector172of each support rib170is configured to couple with the elongate brace162. The connector172generally provides the facility to couple each of the plurality of support ribs170at the desired incremental intervals along the length of the elongate brace162. The connector172is configured to couple to the elongate brace162at any location along the length of the elongate brace162. In other embodiments, the connector172is configured to couple with specific segments or receptacles defined along the length of the elongate brace162. In some embodiments, the connector172is configured to permanently couple with the elongate brace162. In other embodiments, the connector172is configured to removably couple with the elongate brace162. For example, the connector172can define an interference-fit with the elongate brace162. The interference-fit defined by the connector172is a geometry that frictionally engages the elongate brace162.

The connector172can facilitate a tool-less connection between the elongate brace162and the of support rib170. In some examples, the connector172of each support rib170can be manually snapped into place on the elongate brace162. The connector172can be resilient such that it can expand under tension to receive the outer surface of the elongate brace162and relax absent application of tension to exert compressive force on the outer surface of the elongate brace162, which can maintain the position of the support rib170on the elongate brace162.

Other types of connectors172are possible. The connector172could also be configured to couple to the elongate brace162using a fastener or clamp. In some examples, the connector172can be an adhesive substrate with which the elongate brace162is adhered. An adhesive can be used alone or in combination with any contemplated connector172. For example, an interference fit may be augmented by adhering an inner surface of the connector172to an outer surface of the elongate brace162. Adhering can include the use of glues, cements, chemical adhesives, hot-melt adhesives, and other adhesives. The connector172can also be a substrate to which the elongate brace162is welded or otherwise bonded.

The cross-brace176of the support rib170is configured to provide structural support to the outer support surface173of the support rib170. The cross-brace176bridges a gap between the connector172and an outer surface of the support rib170. In some embodiments, the connector172defines a portion of the cross-brace176. In some embodiments, the cross-brace176extends between the connector172and the outer support surface173of the support rib170. In some embodiments, the cross-brace176is surrounded by the outer support surface173.

The support ribs170generally simplify the manufacturing process of a filter element100. In many existing designs, a single, often complex support structure is created as a single piece; such a support structure is only compatible with certain filters. The support ribs170can be a shape that is relatively simple to manufacture, and similarly, the elongate brace162can be relatively simple to manufacture. As such, an inner support structure160having a relatively complex structure can be easily constructed using such components. The support ribs170allow a modular support structure construction and can be used in differing quantities, depending on the particular filter element desired. For example, two filter elements having similar cross-sectional geometries but differing lengths can each be constructed using the same support ribs and the same elongate braces that are cut to a different length. Also, an elongate brace162can accommodate support ribs of different shapes for use in filter elements having differing configurations as long as each of the support ribs defines connector that is configured to couple to the elongate brace162.

The pleated filter media130is generally disposed around the inner support structure160to form the elongate tubular structure100as has been described. The elongate tubular structure110can be formed by wrapping the pleated filter media130around the inner support structure160. In some embodiments, a length of pleated filter media130is wrapped around the inner support structure160and the pleated filter media130is joined to itself along a seam (not shown) to form a loop. The pleated filter media130can be joined to itself along the seam with an adhesive, stitches, staples, welds, and the like. The pleated filter media130can be retained on the inner support structure160by friction, adhesion, and the like. In some embodiments, one or more end caps at the first end136and/or second end138of the pleated filter media130can retain the pleated filter media130on the inner support structure160.

FIG. 4Ais a cross-sectional view of the filter element100ofFIG. 1, where the cross section is viewed from a direction perpendicular to the length of the pleated filter media130. As laid out above with reference toFIGS. 2 and 3, the pleated filter media130is disposed around the inner support structure160, and is supported by the outer support surface173of the support rib170of the inner support structure160. The support rib170of the inner support structure at least partially defines the inner passageway120.

The pleated filter media130defines pleats142between outer pleat folds144and inner pleat folds146. The outer support surface173of each of the plurality of support ribs170generally abuts the inner pleat folds146of the pleated filter media130at least around each corner134. The pleats142generally extend along the media length140(seeFIG. 1, for example). In the current example, the pleats142of the pleated filter media130are characterized by pleat heights h. In some embodiments, the pleats142of the pleated filter media130have pleat heights that are substantially equal. The “pleat height” as used herein is the shortest distance along the media between an inner pleat fold146and an adjacent outer pleat fold144of the pleated filter media130. The shortest distance between each adjacent pleat fold is generally constant along the length of each of the pleats142. In some embodiments, pleats142having “substantially equal” pleat heights are defined as pleats having pleat heights within 10% of the average pleat height of the pleats in the pleated filter media130.

The cross section of pleated filter media130defines two or more corners134. In examples consistent with the current embodiment, the pleated filter media130defines three corners134. The corners134defined by the pleated filter media130abut corresponding corners175of each of the plurality of support ribs170. Various embodiments of the filter element100define elongate tubular structures110defining three corners134joined by faces135(seeFIGS. 1 and 2) to form a triangular cross-sectional shape in a direction perpendicular to the length of the pleated filter media130. In some embodiments, the cross section of the pleated filter media130perpendicular to the media length defines a triangle, wherein the triangle has one longest side150having a length that is greater than the length of each of the other two sides152. In other words, the triangle formed by the faces135(seeFIGS. 1 and 2) defines a longest side150and two minor sides152. The two minor sides152are shorter than the longest side150. In this particular example, the minor sides152have the same length. In this example, the pleated filter media130has a cross-sectional shape that is an isosceles triangle.

The pleated filter media130can define other cross-sectional shapes as well, such as other triangular cross-sectional shapes or even other polygonal shapes. It should be understood that the reference herein to triangular and other polygonal cross-sectional shapes of the pleated filter media encompasses shapes having rounded corners. In some embodiments, the cross-sectional shape of the pleated filter media130is a right triangle. In some embodiments, the cross-sectional shape of the pleated filter media130is not an equilateral triangle. In some embodiments, the cross-sectional shape of the pleated filter media130is a scalene triangle.

In some embodiments, the elongate brace162has a circular cross section in a direction that is perpendicular to the length of the pleated filter media130, and the connector172of each support rib170has an inner arcuate geometry with a diameter smaller than or approximately equal to the diameter of the elongate brace162such that the connector172exerts compressive force on the outer surface of the elongate brace162. In such embodiments, the friction between the connector172and the elongate brace162couples the two components. Other examples are possible wherein the connector172has a structure that is configured to receive the outer surface of the elongate brace162. For example, the elongate brace can have alternate cross-sectional shapes and the connector can have a corresponding shape configured to couple to the elongate brace. Many possible connector geometries are contemplated that provide an interference fit between the connector172and the elongate brace162. By way of example, the connector172can have a polygonal or elliptical cross sectional shape.

FIGS. 4B-4Ddepict cross-sectional views of example support rib geometries. The support ribs depicted inFIGS. 4B-4Deach have outer support surfaces having cross-sectional shapes that are generally triangular.FIG. 4Bdepicts the support rib170ofFIG. 4Ahaving a cross section that is an isosceles triangle.FIG. 4Cdepicts an example support rib170chaving a cross section that is a right triangle.FIG. 4Ddepicts a support rib170dhaving a cross section that is a scalene triangle.

FIG. 4Bis a cross-sectional view of the example support rib170of the filter element100ofFIGS. 2-4A. The support rib170generally has an outer support surface173, a cross-brace176, and a connector172, as described above with reference toFIGS. 2 and 3. In this particular example the outer support surface173of the support rib170has a cross-sectional shape that is an isosceles triangle. The triangular cross section of the outer support surface173is defined by at least two corners175, in particular three corners175. The three corners175of the support rib170are defined by the intersections of three substantially linear segments180,182corresponding to the faces135(seeFIGS. 1-2) of the filter element100. The corners175are rounded. In this example, the corners175are defined by the intersections of a longest side180and two minor sides182.

FIG. 4Cis a cross-sectional view of another example support rib170c. The support rib170chas an alternative geometry to the support rib170(FIG. 4B), but is otherwise consistent with the function of the support rib170as described above with reference toFIGS. 2-4B. The support rib170chas a connector172c, a cross-brace176c, and an outer support surface173c. The outer support surface173cdefines a hypotenuse side180c, a base side181c, and a height side182cthat each correspond to a face of a filter element. The intersections of the hypotenuse side180c, the base side181c, and the height side182cdefine at least two corners175c, in particular three corners175cthat are rounded. The outer support surface173chas a cross-sectional shape that is a right triangle. In this example, the base side181cand the height side182cintersect at a right angle, and the hypotenuse side180cdefines a hypotenuse extending from the base side181cto the height side182c.

FIG. 4Dis a cross-sectional view of an example support rib170d. The example support rib170dhas an alternative geometry to the previously-described support ribs, but is otherwise consistent with the function of the support rib170as described above with reference toFIGS. 2-4B. The support rib170dhas a connector172d, a cross-brace176d, and an outer support surface173d. The outer support surface173generally defines three sides180d,181d,182d. The outer support surface173ddefines a major side (or the longest side)180d, a base side181d, and a height side182d. The intersections of the major side180d, the base side181d, and the height side182ddefine three corners175d. The outer support surface173dhas a cross-sectional shape that is a scalene triangle. In this example, each of the base side181d, the height side182d, and the major side180d—that each correspond to a face of the filter element—have different lengths.

FIG. 4Edepicts a cross-sectional view of an alternate example support rib170e. The support rib170ehas an alternative geometry to the previously described support ribs, but is otherwise consistent with the function of the support rib170as described above with reference toFIGS. 2-4B. The support rib170ehas an outer support surface173e, a cross-brace176e, and a connector172e. In this particular example the outer support surface173eof the support rib170ehas a cross-sectional shape that is an isosceles triangle. The triangular cross section of the outer support surface173eis defined by the three corners175e. The three corners175eof the support rib170eare defined by the intersection of substantially linear segments180e,182ecorresponding to faces of a filter element. In this example, the corners175are defined by the intersections of a major side, or longest side,180eand the two minor sides182e.

Contrary to the previously described support ribs, here the connector172eis defined by a recess in the outer support surface173e. The major side180eof the triangular cross section of the outer support surface173eis discontinuous as the recess defining the connector172eis located at the major side180e. As such, the connector172eis not completely surrounded by the outer support surface173eof the support rib170e; rather, the connector172eis partially surrounded by the outer support surface173e. Similarly, the cross-brace176eis not completely surrounded by the outer support surface173eof the support rib170eas was shown inFIG. 4B; rather, the cross-brace176eis partially surrounded by the outer support surface173eand partially surrounded by the connector172e. However, the cross-brace176eis surrounded by an outer surface of the support rib defined by the outer support surface173eand the connector172e. The connector172epartially defines the cross-brace176e. Similar to embodiments previously described, the outer support surface173eof the support rib170ecan still be described as being configured to abut inner pleat folds of pleated filter media around each corner175e. Also, the outer support surface173eof the support rib170eis configured to abut a substantial portion of the inner pleats folds of the pleated filter media.

A connector defined by a recess in a discontinuous outer support surface as described with reference toFIG. 4Ecan also be applied to the support ribs described above with reference toFIGS. 4B-4Dand also support ribs described later herein. The connector configuration described here can be incorporated in other support rib constructions, such as those depicted inFIGS. 4B-4D.

The example support ribs ofFIGS. 4C-4Ecan be incorporated in filter elements generally consistent with those described with reference toFIG. 1. In such embodiments, the inner pleat folds of pleated filter media will generally abut the respective outer support surfaces of the particular support rib employed, such that the pleated filter media defines a respective triangular cross section perpendicular to the length of the pleated filter media130.

FIG. 5is a flowchart outlining an example method of forming a filter element1000. The method1000can be used to produce a filter element having an inner support structure and pleated filter media wrapped around the inner support structure. The method of forming a filter element1000can be used to construct a filter element consistent with the filter elements described above with reference toFIGS. 1-4E, but also those that will be discussed further in this specification.

No more than one elongate brace is obtained1010. A plurality of support ribs are formed1020. Each of the plurality of support ribs are coupled to the elongate brace1030. Pleated filter media is wrapped around the support ribs1040.

The elongate brace that is obtained can have a function and structure consistent with the elongate braces described above with reference toFIGS. 2-4A. The elongate brace can also be constructed of materials consistent with those described above. In some embodiments, an elongate brace is obtained by forming a tubular structure from a plastic mesh material, or formed through other approaches described earlier herein.

The plurality of support ribs are formed1020to have a function and structure consistent with the support ribs described above with reference toFIGS. 2-4E. The formed plurality of support ribs can also be constructed of materials consistent with those described above. In some embodiments, forming a plurality of support ribs1020includes forming an outer support surface on each support rib. In some embodiments, forming a plurality of support ribs1020includes forming a cross-brace in each support rib. The cross-brace can be surrounded by an outer surface of the support rib. In some embodiments, the outer support surface of each formed rib can define two or more corners. In some embodiments, each of the formed ribs is substantially similar. Substantially similar support ribs can be, in some embodiments, identical with the exception of minor manufacturing imperfections. Substantially similar support ribs will have the same shape and substantially equal dimensions. Support ribs can be formed1020consistently with approaches described earlier herein.

The support ribs can be coupled to the elongate brace1030via an interference fit. Each of the plurality of support ribs can be coupled to the elongate brace1030at incremental intervals along the length of the elongate brace. In some embodiments, coupling the plurality of support ribs to the elongate brace1030includes adhering each of the support ribs to the elongate brace. Adhering can include the use of glues, cements, chemical adhesives, hot-melt adhesives, and other adhesives. Adhering can also include welding or otherwise bonding to couple the support rib to the elongate brace1030. The method of coupling the support ribs to the elongate brace1030can be otherwise consistent with connectors of the support ribs described above with reference toFIGS. 2-4E.

Wrapping pleated filter media around the support ribs1040forms an elongate tubular structure. The elongate tubular structure generally extends from a first end to a second end. The elongate tubular structure defines an inner passageway. In some embodiments of the current method, the filter media is pleated to form the pleated filter media that is wrapped around the support ribs. The pleated filter media can be consistent with the pleated filter medias described above with reference toFIGS. 1-4A.

In some examples, a first end cap is coupled to the pleated filter media at the first end. In such examples, the elongate brace can be coupled to the first end cap. In some examples, a second end cap is coupled to the pleated filter media at the second end. In such examples, the elongate brace can be uncoupled from the second end cap. Example end caps will be described with respect toFIGS. 6-7 and 13-14.

FIGS. 6 and 7depict an example implementation of filter elements such as those described in association withFIGS. 1-5. A fluid filter assembly200is generally configured to provide gas or liquid filtration, as described above with reference toFIG. 1. The fluid filter assembly200has a first filter element201, a second filter element207, a first end cap202, a second end cap204, and a third end cap205.

The fluid filter assembly200is generally configured to be received by a filter receptacle in a filtration system. The fluid filter assembly200provides an increased filtration surface area as compared to some existing filter assemblies that are also configured to be received by the filter receptacle of the filtration system. Providing an increased filtration surface area can enable the fluid filter assembly200to handle a higher fluid flow rate for a given pressure. The increased filtration surface area can also enable the fluid filter assembly200to operate at a lower pressure for a given fluid flow rate. The increased filtration surface area can further allow increased intervals between servicing or replacing the fluid filter assembly200.

The first filter element201has a first elongate tubular structure210defined by a first pleated filter media230. The first elongate tubular structure210can be constructed in accordance with the tubular structures described earlier herein. The first elongate tubular structure210is a tubular structure with two or more faces235and two or more corners234defined by the first pleated filter media230. The first elongate tubular structure210defines a first inner passageway220. The first pleated filter media230, and therefore the first elongate tubular structure210has a first end236and a second end238. The first inner passageway220extends from the first end236to the second end238of the first pleated filter media230. A first media length240is defined from the first end236to the second end238of the first pleated filter media230.

The first pleated filter media230is generally consistent with the pleated filter media described above with reference toFIGS. 1-4E. The first pleated filter media230has inner pleat folds and outer pleat folds defining pleats. The pleats of the first pleated filter media230have pleat heights. In some embodiments, the first pleated filter media230defines pleats having substantially equal pleat heights.

In some examples, the first pleated filter media230is disposed on a first inner support structure260. The first inner support structure260is a rigid structure configured to support the first pleated filter media230. The first inner support structure260is disposed in the first elongate tubular structure210. The first inner support structure260can be consistent with the inner support structures described above with reference toFIGS. 1-4E.

In some embodiments, the first inner support structure260has no more than one elongate brace262configured to support the first pleated filter media230. The elongate brace262can extend between the first end236and the second end238of the first pleated filter media230. The elongate brace262can be consistent with the elongate braces described above with reference toFIGS. 1-4A.

In some embodiments, first inner support structure260has a first plurality of support ribs270. In such embodiments, the first support ribs270are coupled to the elongate brace262. The first support ribs270can be consistent with the support ribs described above with reference toFIGS. 1-4E. For example, each of the first plurality of support ribs270can have a connector defining an interference-fit with the elongate brace262.

The second filter element207has a second elongate tubular structure211defined by a second pleated filter media231. The second elongate tubular structure211can be constructed in accordance with the tubular structures described earlier herein. The second elongate tubular structure211is a tubular structure with two or more faces235and two or more corners234defined by the second pleated filter media231. The second elongate tubular structure211defines a second inner passageway221. The second pleated filter media231, and therefore the second elongate tubular structure211, has a first end237and a second end239. The second inner passageway221extends from the first end237to the second end239of the second pleated filter media231. A second media length241is defined from the first end237to the second end239of the second pleated filter media231. The second media length241is parallel to the first media length240in many embodiments.

The second pleated filter media231is generally consistent with the pleated filter medias described above with reference toFIGS. 1-4E. The second pleated filter media231has inner pleat folds and outer pleat folds defining pleats. The pleats of the second pleated filter media231have pleat heights. In some embodiments, the second pleated filter media231defines pleats having substantially equal pleat heights.

In some examples, the second pleated filter media231is disposed on a second inner support structure261. The second inner support structure261is a rigid structure configured to support the second pleated filter media231. The second inner support structure261is disposed in the second elongate tubular structure211. The second inner support structure261can be consistent with the inner support structures described above with reference toFIGS. 1-4E.

In some embodiments, the second inner support structure261has no more than one elongate brace263configured to support the second pleated filter media231. The elongate brace263can extend between the first end237and the second end239of the second pleated filter media231. The elongate brace263can be consistent with the elongate braces described above with reference toFIGS. 1-4A.

In some embodiments, second inner support structure261has a second plurality of support ribs271. In such embodiments, the second support ribs271are coupled to the elongate brace263. The second support ribs271can be consistent with the support ribs described above with reference toFIGS. 1-4E. For example, each of the second plurality of support ribs271can have a connector defining an interference-fit with the elongate brace263.

The filter assembly200is configured to be received by a cylindrical filter receptacle in some embodiments. The first and second filter elements201and207each generally have a filtration surface area through which fluid can pass and be filtered. The filtration surface area is an area of the pleated filter media130available for filtration, and includes the corners234and faces235of the first and second pleated filter medias230and231. The combined filtration surface area of the first filter element201and the second filter element207is greater than a filtration surface area of many cylindrical tubular filter assemblies that are configured to be received by a cylindrical filter receptacle.

The first and second filter elements201and207are generally arranged such that a portion of the filtration surface area of the first filter element201is adjacent to a portion of the filtration surface area of the second filter element207. As applied to the two filter elements, the phrase “adjacent to” used herein refers to an orientation in which the filtration surface areas are proximate, but generally not making contact. In some embodiments, the adjacent filtration surface areas are generally parallel to each other. The first and second filter elements201and207generally adjacent to each other such that there is a distance between the two filter elements defining a fluid flow path in the region between the two filter elements to enable fluid filtration through the adjacent filtration surface areas. In some embodiments, the first and second filter elements201and207substantially mirror each other. In some embodiments, the fluid filter assembly200has one or more structures that define fluid flow paths through the fluid filter assembly200, such as one or more end caps. End caps are generally coupled at the ends of the first and second filter elements201and207. In some examples, an end cap forms a barrier to fluid flow, such as blocking the inner passageway. In some examples, an end cap defines a flow path there-through, thereby allowing fluid communication between an inner passageway and an external volume. In some embodiments, a tubular structure of a filter element is configured to have one open end and one closed end that is defined by respective end caps. In such embodiments, the filter element200is configured to direct fluid to flow through the first or second end and through the filter media of the tubular structure.

The first end cap202(particularly visible inFIG. 6) is configured to allow fluid to flow between an external source or sink and each of the first inner passageway220of the first filter element201and the second inner passageway221of the second filter element207. The first end cap202is coupled to the first end236of the first pleated filter media230and the first end237of the second pleated filter media231. The first end cap202defines a first opening222in communication with the first inner passageway220and a second opening223in communication with the second inner passageway221.

The second end cap204(particularly visible inFIG. 7) is coupled to the second end138of the first elongate tubular structure210. The second end cap204forms a barrier across the first inner passageway220. The third end cap205is coupled to the second end239of the second elongate tubular structure211. The third end cap205forms a barrier across the second inner passageway221. In some embodiments, a single end cap can couple to both the second end238of the first elongate tubular structure210and the second end239of the second elongate tubular structure211to form a barrier across both the first inner passageway220and the second inner passageway221.

The first and second pleated filter medias230and231are configured to allow fluid flow there through. In some examples, fluid flows through the first pleated filter media230into the first inner passageway220and out of the fluid filter assembly200through the first opening222in the first end cap202, and fluid flows through the second pleated filter media231into the second inner passageway221and out through the second opening223in the first end cap202. In other examples, fluid flows through the first pleated filter media230and the second pleated filter media231in the opposite direction.

FIG. 8is a schematic cross-sectional view of a filtration system390, where the cross section is viewed from a direction perpendicular to a length of a filter media. The filtration system390is an example implementation of a fluid filter assembly300consistent with the fluid filter assemblies described above with reference toFIGS. 6-7. The fluid filter assembly300has a first filter element301and a second filter element307that can also be consistent with those described above.

In the filtration system390, the fluid filter assembly300is disposed in a filter receptacle354generally defining a circular cross-section surrounding the fluid filter assembly300. The fluid filter assembly300provides an increased filtration surface area compared to some existing cylindrical tubular pleated filter assemblies that are also configured to be received by the filter receptacle, which can have advantages such as those described above with reference toFIGS. 6-7.

The first filter element301has a first pleated filter media330. The first pleated filter media330generally has a triangular cross-sectional shape in a direction perpendicular to a length of the first pleated filter media330. As such, the cross section of the first pleated filter media330defines a first triangle303. The first triangle303of the first pleated filter media230is generally each defined by three corners334and three sides350,352. The first triangle303is an isosceles triangle. The first triangle303has a longest side350two minor sides352. The longest side350of the first triangle303has a length l that is greater than the length of each of the other two minor sides352.

The second filter element307has a second pleated filter media331. The second pleated filter media331generally has a triangular cross-sectional shape. As such, the cross section of the second pleated filter media331perpendicular to a length of media defines a second triangle308. The second triangle308of the second pleated filter media331is generally each defined by three corners334and three sides351,352. The first triangle303is an isosceles triangle. The second triangle308has a longest side351and minor sides352. The longest side351of the second triangle308has a length l that is greater than the length of the other two minor sides352.

In some embodiments, the length l of the longest side350of the first triangle303is substantially equal to the length l of the longest side351of the second triangle308, meaning that the length l of the longest side350of the first triangle303is within 10% of the length l of the longest side351of the second triangle308. In some embodiments, the first and second triangles303and308, like the first and second filter elements301,307are substantially identical.

As discussed above, the first triangle303generally adjacent to the second triangle308such that a face of the first pleated filter media330is spaced a distance d away from a face of the second pleated filter media331. In the current figure, the adjacent faces correspond to the longest side350of the first triangle303and the longest side351of the second triangle308. In particular, the first and second triangles303and308are arranged such that the longest side350of the first triangle303is parallel to the longest side351of the second triangle308. In some examples, the length of the longest side350of the first triangle303and the longest side351of the second triangle308are each no more than 10% less than another inner dimension of the filter receptacle that is configured to accommodate the longest side350. For example, a filter receptacle can have a generally rectangular cross-sectional shape, wherein the dimension of the filter receptacle configured to accommodate the element is the length between opposite corners. Other filter receptacle shapes are contemplated.

The first triangle303and the second triangle308are generally arranged in the fluid filter assembly300such that the filtration surface area of the first pleated filter media330and the second pleated filter media331are increased for the given filter receptacle354relative to a filter element having a pleated filter media configuration forming a single tubular cylinder. This relative increase in filtration surface area can be represented by a ratio of the total linear length of the sides and corners of the first and second triangles303and308relative to the open cross-sectional area of the filter receptacle. In some embodiments, a ratio of the total length of the sides of the first filter element301and the second filter element307to an open cross-sectional area of a circle encompassing the first triangle and the second triangle is greater than 0 and less than 10.

The first filter element301and the second filter element307have similar configurations to that described in previous figures. The first filter element301can have a first tubular structure (such as is visible inFIG. 1) defined by the first pleated filter media330. The first filter element301has a first inner support structure360disposed within a first inner passageway320of the first tubular structure. The first inner support structure360can be consistent with the inner support structures described previously herein. The first inner support structure360generally has a first outer support surface373. The first inner support structure360defines a shape to which the first pleated filter media330conforms. The first inner support structure360maintains the triangular cross-sectional shape of the first pleated filter media330. In some embodiments, the first outer support surface373abuts a substantial portion of the inner pleat folds of the first pleated filter media330. In some embodiments, the first inner support structure360at least partially defines the first inner passageway320.

The second filter element307can have a second tubular structure (such as is visible inFIG. 1) defined by the second pleated filter media331. The second tubular structure defines a second inner passageway321. The second filter element307has a second inner support structure361disposed within the second inner passageway321. The second inner support structure361generally has a second outer support surface374. The second inner support structure361defines a shape to which the second pleated filter media331conforms. The second inner support structure361maintains the triangular cross-sectional shape of the second pleated filter media331. In some embodiments, the second outer support surface374abuts a substantial portion of the inner pleat folds of the second pleated filter media331. In some embodiments, the second inner support structure361at least partially defines the second inner passageway321.

FIG. 9depicts another example filter element400consistent with some example embodiments andFIG. 10is a cutaway view of the filter element400depicted inFIG. 9. The filter element400generally has a pleated filter media430disposed around an inner support structure460. The inner support structure460is also visible inFIG. 11. The filter element400is configured in an elongate tubular structure410defining an inner passageway420, and the inner support structure460is disposed within the inner passageway420. The pleated filter media430is generally consistent with pleated filter media already described herein. For example, the pleated filter media has outer pleat folds and inner pleat folds each extending from a first end436to a second end438of the pleated filter media430. The inner passageway420extends from the first end436to the second end438of the pleated filter media430.

In embodiments consistent with the current figures, the pleated filter media430of the filter element400defines two corners434that joins a relatively flat face450to a substantially curved face452resulting in a “D” cross sectional shape (described below in the discussion ofFIG. 12A). The corners434are substantially curved planes.

The inner support structure460is configured to maintain the shape of the pleated filter media430and is generally consistent with inner support structures already described herein. For example, the inner support structure460has no more than one elongate brace462and a plurality of support ribs470coupled to the elongate brace462. The elongate brace462extends between the first end436and the second end438of the pleated filter media430. The inner support structure460generally has an outer support surface473that defines the cross-sectional shape of the inner passageway420. The elongate brace462can have alternate configurations that have already been described herein.

The support ribs470are coupled to the elongate brace462at incremental intervals along the length of the elongate brace462. Each of the support ribs470can be substantially identical. Each of the support ribs470at least partially defines the inner passageway420and has a connector472defining an interference-fit with the elongate brace462, although alternate or additional connections can be used which have already been described. The support ribs470define the outer support surface473of the inner support structure460, where the outer support surface473abuts a substantial portion of the inner pleat folds of the pleated filter media430. The support ribs470can be characterized as having at least a first support rib477disposed towards the first end436of the elongate tubular structure of the pleated filter media430, a second support rib478disposed towards the second end438of the elongate tubular structure, and a third support rib479disposed between the first support rib477and the second support rib478.

As has been described, one or more end caps (not currently depicted) can be coupled to the filter element400to direct fluid flow through the pleated filter media430.

The current example filter element400ofFIGS. 9-11has pleated filter media430and support ribs470having a cross-sectional shape distinguishable from those of corresponding components described with reference toFIGS. 1-8.FIG. 12Ais a cross-sectional view of the filter element400ofFIGS. 9-11, where the cross section is viewed from a direction perpendicular to the length440of the pleated filter media430. The pleated filter media430is disposed around the inner support structure460. The pleated filter media430is generally supported by the outer support surface473of the support ribs470of the inner support structure460. The pleated filter media430has pleats442defined by outer pleat folds444and inner pleat folds446. In a variety of embodiments, a substantial portion of the pleats have substantially equal pleat heights.

Generally, the cross-sectional shape of the pleated filter media430defines two or more corners434. Generally, the outer support surface473of the support rib abuts the inner pleat folds446around each corner434. In this particular example, the cross-sectional shape of the pleated filter media430defines two corners434, a substantially arced segment452(corresponding to the curved plane452visible inFIGS. 9 and 10) coupled to a linear segment450(corresponding to the relatively flat plane450visible inFIGS. 9 and 10) at the corners434. In some examples, the substantially arced segment is configured to be concentric with an inner surface of a filter receptacle. Similar to the phrase “substantially curved plane,” the phrase “substantially arced segment” is defined herein to encompass an arcuate section but also a section having multiple facets that approximate the shape of an arc.

FIG. 12Bis a cross-sectional view of the example support rib470of the filter element400ofFIGS. 9-12A, where the cross section is viewed from a direction perpendicular to the length of the pleated filter media430. Each of the support ribs470generally has an outer support surface473, a cross-brace476, and a connector472. The outer support surface473defines two or more corners475. The cross-brace476is surrounded by an outer surface of the support rib470. Here, the cross-brace476is surrounded by the outer support surface473of the support rib470. Also, in the current embodiment, the connector472can be described as defining a portion of the cross-brace476.

FIG. 12Cdepicts an alternate example support rib770consistent with some embodiments. The support rib770has an outer support surface773, a cross-brace776, and a connector772. The outer support surface773defines two or more corners775. The connector772is defined by a recess in the outer support surface773such that the connector772is only partially surrounded by the outer support surface773. Here, while the cross-brace776is surrounded by an outer surface of the support rib770, the cross-brace776is only partially surrounded by the outer support surface773of the support rib770. Described differently, here the cross-brace776is surrounded by the outer support surface773of the support rib770and the connector772.

WhileFIGS. 12B and 12Cdepict two examples of support ribs, it will be appreciated that alternative configurations of support ribs are possible. It may be desirable to have an outer support surface having alternate shapes to retain corresponding cross-sectional shapes from the filter media. Also, it may be desirable to incorporate additional cross-braces. It also may be desirable to have support ribs that have connectors with alternate configurations, as has been described.

FIGS. 13 and 14depict an example implementation of a filter element. A fluid filter assembly500has a first filter element501, a second filter element507, a first end cap502and a second end cap504. The first filter element501and the second filter element507are generally consistent with the filter element described in association withFIGS. 9-12A.

The first filter element501has filter media510defining a first tubular structure having a first inner passageway520extending from a first end536to a second end538of the first pleated filter media510to define a first media length540. The second filter element507has second pleated filter media511defines a second tubular structure having a second inner passageway521extending from a first end537to a second end539of the second pleated filter media511to define a second media length541. The first media length540and the second media length541are parallel in many embodiments. A first inner support structure is disposed within the first pleated filter media510and a second inner support structure is disposed within the second pleated filter media511, although they are not currently visible (see for example,FIG. 11). The cross section of the first pleated filter media510perpendicular to the first media length540and the cross section of the second pleated filter media511media perpendicular the second media length541is consistent with that described in association withFIG. 12A.

The first end cap502is coupled to the first end536of the first pleated filter media510and the first end537of the second pleated filter media511. The first end cap502defines a first opening503in communication with the first inner passageway520and a second opening506in communication with the second inner passageway521. The second end cap504is coupled to the second end538of the first pleated filter media510and the second end539of the second pleated filter media511. The second end cap504defines a barrier across the inner passageways520,521. In some embodiments it can be desirable to use two end caps instead of the second end cap504to define a barrier across the inner passageways520,521, similar to the embodiment depicted inFIG. 7.

FIG. 15is a cross-sectional view of a filtration system. The filtration system depicts a fluid filter assembly600disposed in a filter receptacle654. The fluid filter assembly600generally has a first filter element601having first pleated filter media630and a second filter element607having second pleated filter media631. The fluid filter assembly600can be consistent with the fluid filter assembly500discussed above with respect toFIGS. 13-14. The cross section is in the direction perpendicular to the length of the first pleated filter media630and the second pleated filter media631.

Similar to the embodiment depicted inFIG. 8, here the filter receptacle654generally defines a circular cross section that is configured to accommodate a fluid filter assembly600. The fluid filter assembly600provides an increased filtration surface area compared to some existing cylindrical tubular pleated filter assemblies that are also configured to be received by the filter receptacle654.

Each of the first filter element601and the second filter element607is generally consistent with the filter element described and depicted inFIG. 12A. The first filter element601has first filter media630and a first inner support structure660that mutually define a first inner passageway620. The second filter element607has a second filter media631and a second inner support structure661that mutually define a second inner passageway621. The first pleated filter media630in the first filter element601and the second pleated filter media631in the second filter element607each define corners634joining a linear segment650to a substantially arced segment652. The linear segment650of the first pleated filter media630is adjacent to, albeit spaced from, the linear segment650of the second pleated filter media631. The linear segment650of the first pleated filter media630is parallel to the linear segment650of the second pleated filter media631.

In some embodiments, the substantially arced segment652of the first pleated filter media630and the substantially arced segment652of the second pleated filter media631are each configured to be concentric with the inner surface of the filter receptacle654.

It should also be noted that, as used in this specification and the appended claims, the phrase “configured” describes a system, apparatus, or other structure that is constructed or configured to perform a particular task or adopt a particular configuration. The phrase “configured” can be used interchangeably with other similar phrases such as “arranged”, “arranged and configured”, “constructed and arranged”, “constructed”, “manufactured and arranged”, and the like.

All publications and patent applications in this specification are indicative of the level of ordinary skill in the art to which the present technology pertains. All publications and patent applications are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated by reference.

This application is intended to cover adaptations or variations of the present subject matter. It is to be understood that the above description is intended to be illustrative, and not restrictive.