USRE42174E1 - Filter with efficiently sealed end - Google Patents

Abstract

A filter element has a resiliently compressible end cap at a first axial end sealing the filter and providing sealed engagement with a flow tube.A filter assembly comprising a filter media element having a first end and a second end, a first end cap disposed at the first end, and a second end cap disposed at the second end. The filter media element is shaped to form a hollow interior extending from the first end to the second end. The hollow interior defines an inner boundary of the element and the outer surface of the element defines an outer boundary. The second end cap covers both the filter media element and the hollow interior at the second end.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. Reissue patent application Ser. No.11/759,884, filed Jun.7,2007, which is a reissue of U.S. Pat. No.6,902,598 and incorporated herein by reference.

BACKGROUND AND SUMMARY

The invention relates to fluid filters, and more particularly to improved sealing of the filter media end.

The invention arose during continuing development efforts relating to filter elements having pleated filter media having a plurality of pleats in a closed loop, typically annular, for example as shown in U.S. Pat. Nos. 6,149,700, 6,261,334, 6,391,076, 6,398,832, all incorporated herein by reference. The closed loop pleated filter media has an outer perimeter defined by a plurality of outer pleat tips, and an inner perimeter defined by a plurality of inner pleat tips, and has a hollow interior extending along a given axis. Fluid flows axially in the hollow interior, before or after flow through the media, depending on whether the flow is inside-out or outside-in. The filter element has an open axial end providing an axial flow passage therethrough along the axis communicating with the hollow interior.

The present invention relates to improved sealing of the pleat ends at the open axial end of the filter element, including improvements in both the effectiveness of the sealing and manufacturing efficiency for cost reduction. The invention further relates to other filter media end sealing techniques.

BRIEF DESCRIPTION OF THE DRAWINGSPrior Art

FIG. 1 is taken fromFIG. 1 of incorporated U.S. Pat. No. 6,149,700.

FIG. 2 is taken fromFIG. 2 of the noted incorporated '700 patent and is a sectional view taken alongline2—2 of FIG.1.

FIG. 3 illustrates prior art and shows the open axial end of a closed loop pleated media filter element prior to potting of the end cap.

FIG. 4 illustrates prior art and shows the open axial end of the filter element ofFIG. 3 after potting of the end cap.

FIG. 5 is taken fromFIG. 11 of the incorporated '700 patent, and is a view of a mold for molding an end cap onto pleated filter media of a filter element.

FIG. 6 is taken fromFIG. 10 of the incorporated '700 patent, and is a view like a portion ofFIG. 2, and shows an alternate embodiment.

Present Invention

FIG. 7 is like FIG.2 and shows the present invention.

FIG. 8 is like FIG.3 and shows the present invention.

FIG. 9 is like FIG.4 and shows the present invention.

FIG. 10 is like FIG.5 and shows the present invention.

FIG. 11 is like FIG.6 and shows the present invention.

FIG. 12 is like FIG.7 and shows a further embodiment.

FIG. 13 is like FIG.7 and shows a further embodiment.

FIG. 14 is like FIG.9 and shows a further embodiment.

DETAILED DESCRIPTION OF THE INVENTIONPrior Art

FIGS. 1 and 2 show afilter20 including afilter element22 contained within ahousing24.Filter element22 is provided bypleated filter media26,FIG. 2, having a plurality ofpleats28,FIGS. 3,4, in a closed loop, typically an annulus, having anouter perimeter30 defined by a plurality of outerpleat tips32, and aninner perimeter34 defined by a plurality of innerpleat tips36. The annular closed loop has ahollow interior38 extending along anaxis40.Housing24 is typically cylindrical and is provided byhousing sections42 and44 mounted to each other in conventional manner such as by overcenter spring clip type clamps such as46, or in other suitable manner. The housing has aninlet50 admitting inlet fluid, such as air or liquid, radially and/or tangentially intoannular space52 within the housing aroundfilter element22. Alternatively, the inlet may be at an axial end of the housing, for example as in incorporated U.S. Pat. No. 6,391,076. The housing may include an interior dam ordeflection surface54 for blocking direct impact againstfilter element22 and/or for directing flow, for example in a spiral or toroidal pattern. The fluid flows laterally or radially inwardly throughfilter media26 intohollow interior38, and then the clean fluid flows axially rightwardly inFIG. 2 inhollow interior38 alongflow passage56 as shown atarrows58,59. Alternatively or additionally, the fluid may flow axially through the filter media as in the noted incorporated '076 patent.

Flow passage56 extending alongaxis40 circumscribeshollow interior38 and has aflow perimeter60 greater thaninner perimeter34 defined by innerpleat tips36, as described in the incorporated '700 patent.Flow perimeter60 is less thanouter perimeter30 defined by outerpleat tips32.Inner perimeter34 defines and bounds a first cross-sectional area.Flow perimeter60 defines and bounds a second cross-sectional area. The second cross-sectional area is greater than the first cross-sectional area.Outer perimeter30 defines and bounds a third cross-sectional area. The second cross-sectional area is less than the third cross-sectional area.Filter element22 has first and secondaxial ends62 and64.Axial end62 is open and providesaxial flow passage56 therethrough. Anend cap66 of soft resilient compressible material, such as foamed potted urethane, axially abuts theaxial ends68 of the pleats.End cap66 has aninner perimeter70 greater thaninner perimeter34 defined by innerpleat tips36.End cap66 partially covers theaxial ends68 of the pleats such that the laterallyoutward portions72 of theaxial ends68 of thepleats28 are covered byend cap66 but not the laterallyinward portions74 of theaxial ends68 of the pleats, such that the laterallyinward portions74 of the axial ends of the pleats are uncovered and exposed ataxial end62 offilter element22, FIG.4.

In one embodiment, secondaxial end64 offilter element22 is closed. Asecond end cap76,FIG. 2, of soft compressible resilient material, such as foamed potted urethane, is provided atsecond end64 offilter element22 and completely covers theaxial ends78 of the pleats including the outerpleat tips32 and the innerpleat tips36 ataxial end64.End cap76 also includes acentral section80 spanning and completely coveringhollow interior38 offilter element22 ataxial end64 of the filter element.Housing section44 includes an annularinterior sidewall82 extending partially axially into the housing to locate and retainfilter element22 ataxial end64. In other embodiments,central section80 ofend cap76 is omitted, and a portion ofhousing44 extends intohollow interior38 offilter element22 to closeaxial end64 of the filter element and to positionaxial end64 of the filter element within the housing. Further embodiments are shown in the noted incorporated '076 patent.End cap76 includes anannular ridge84 engagingaxial end wall85 ofhousing section44 and slightly axially compressed thereagainst to further aid in retention offilter element22 within the housing and to accommodate axial tolerances.End cap66 also includes anannular ridge86 engagingaxial end wall88 ofhousing section42 and slightly radially compressed thereagainst to aid in retainingfilter element22 within the housing and to accommodate axial tolerances and also to provide an axial seal to prevent bypass of dirty air fromannular chamber52 aroundaxial end62 of the filter element.Axial end wall88 ofhousing section42 has anoutlet flow tube90 extending therethrough. In addition to or alternatively to the axial seal at86,end cap66 provides a radial seal at70 againstoutlet flow tube90.

End cap66 has asidewall92 extending axially away fromaxial ends68 ofpleats28 ataxial end62 offilter element22. The sidewall has the notedinner perimeter70, and has anouter perimeter94. As noted above,inner perimeter70 ofsidewall92 is greater thaninner perimeter34 offilter element22 defined byinner pleat tips36.Inner perimeter70 ofsidewall92 ofend cap66 is less thanouter perimeter30 offilter element22 defined byouter pleat tips32.Outer perimeter94 ofsidewall92 ofend cap66 is greater thanouter perimeter30 offilter element22 defined byouter pleat tips32.Flow tube90 has aninner section96 axially facing the axial ends68 ofpleats28.Inner section96 offlow tube90 has aninner perimeter98 and anouter perimeter100.Outer perimeter100 is greater thaninner perimeter70 ofsidewall92 ofend cap66, such that asfilter element22 atend cap66 is axially slid rightwardly overinner section96 offlow tube90,end cap66 is radially compressed to expandinner perimeter70 alongouter sidewall100 of flow tubeinner section96 to effect the noted radial seal.Inner perimeter70 ofend cap66 is preferably stepped, as shown at71 inFIG. 8 of the noted incorporated '700 patent, to have slightly progressively decreasing diameters from right to left as viewed therein, to receive and guideinner section96 offlow tube90 therealong and increase radial sealing pressure.End cap66 circumscribesinner section96 offlow tube90 and bears radially thereagainst at70 in sealing relation to form the noted radial seal thereat.End wall88 ofhousing section42 axially faces axial ends68 ofpleats28, andend cap66 also bears axially againstend wall88 in sealing relation at86 to form the noted axial seal thereat.

Anouter liner102,FIG. 2, provided by an expanded wire mesh or screen or perforated metal or plastic, circumscribesfilter element22 alongouter pleat tips32 and has anaxial end section104 extending axially beyond the axial ends68 ofpleats28. An inner liner may also be provided atinner perimeter34 alonginner pleat tips36. As above described,flow tube90 communicates withhollow interior38 of the filter element alongflow passage56 and extends axially from the axial end of the filter element.End cap66 at the axial end of the filter element bears radially between and is radially compressed between and againstsection104 ofouter liner102 andinner section96 offlow tube90.Outer liner102 extends axially at104 intoend cap66 and is potted therein during the molding process, as described in the incorporated '700 patent. As noted above,sidewall92 ofend cap66 extends axially away from the axial ends68 ofpleats28 at the axial end of the filter element.Outer perimeter94 of the end cap sidewall circumscribesouter liner section104. The filter element may also include an inner liner103,FIG. 5, alonginner pleat tips36.

Pleats28 have pairs of walls defining axially extendinginterior channels106,FIG. 3, and also as shown inFIG. 7 of the incorporated '700 patent, and axially extendingexterior channels108. The walls of the pleats defining theexterior channels108 are sealed to each other nearaxial end62 of the filter element by heat seal bonding along glue strips, also known as hot melt, such as110, and as shown in the incorporated '700 patent atFIGS. 4-6,9, and for example as disclosed in U.S. Pat. No. 5,106,397, incorporated herein by reference. This prevents bypass of dirty air around the axial ends of the pleats at inner exposedportions74. Fluid such as air flowing radially inwardly through the filter media as shown at112, and as shown in the incorporated '700 patent atFIG. 4, or alternatively flowing axially as shown in the incorporated '076 patent atFIGS. 15,16 thereof, must flow through the sidewalls ofpleats28 before such fluid can flow axially through hollow interior40 as shown atarrow58 or axially through theinward portions74 of the axial ends68 of the pleats as shown atarrow59. Some of such air can flow axially rightwardly as shown atarrow59 axially alonginterior channels106, and the balance of the air continues radially inwardly as shown atarrow114, and as shown in the incorporated '700 patent inFIG. 4, and then flows axially as shown atarrow58. The axial ends ofexterior channels108 at the axial end of the filter element are blocked by the noted hot melt seal bonding along adhesive strips110. Fluid flowing through the filter element is forced to pass fromexterior channels108 tointerior channels106.FIGS. 6 and 9 of the incorporated '700 patent show the seal bonded adhesive110 extending inexterior channels108 all the way frominner pleat tips36 toouter pleat tips32 as idealized. If the seal bond does not extend all the way frominner pleat tip36 toouter pleat tip32, then the shape of theinterior channel106 atouter pleat tip32 will generally be more rounded and the walls ofpleats28 formingexterior channels108 atouter pleat tips32 will usually be closer together. In an alternative, the adhesive seal bond inexterior channels108 may extend frominner pleat tips36 only partially towardsouter pleat tips32, and the outer portions ofexterior channels108 are blocked at the axial end of the filter element atend cap66. During the molding potting process, the liquid castable material into which the pleated filter media is dipped will foam up a short distance axially into the channels between the pleats, as shown in the incorporated '700 patent at inner section116 inFIGS. 4,8,9 thereof, of the end cap which has migrated a distance118,FIG. 4 of the incorporated '700 patent, between the pleats. The spacing of glue strips110 on the pleats from the axial ends68 of the pleats may be adjusted as desired in standard glue seal strip applicator machines. Preferably, glue seal strips110 are spaced fromaxial ends68 of the pleats by a small distance118 to enable a slight deformation of the axial ends68 of the pleats by a dam in the mold during the molding potting process, to keep the liquid castable material of the end cap from flowing radially inwardly intoinner portions74 of the pleat ends which are desired to be exposed, which molding process and dam are disclosed in the noted '700 patent, and noted hereinafter. Alternatively, seal glue strips110 may be applied at axial ends68 of the pleats, without gap118 therebetween.

FIG. 5 shows amold120 for molding or pottingend cap66 ontopleated filter media26 of the filter element. The mold has atrough122 extending along an annular first perimeter and holding liquid castable material, such as urethane, therein into which axial ends68 ofpleats28 are dipped. The mold has aninsert124 with anupstanding dam126 extending along a second annular perimeter circumscribed by the noted annular perimeter oftrough122.Dam126 engages axial ends68 of the pleats betweenouter pleat tips32 andinner pleat tips36 and impedes flow of liquid castable material laterally radially inwardly towardsinner pleat tips36.Trough122 partially spans axial ends68 of the pleats such that the laterallyoutward portions72 of the axial ends of the pleats are covered by liquid castable material but not the laterallyinward portions74 of the pleats, such that laterallyoutward portions72 of the axial ends68 of the pleats are covered byend cap66, and the laterallyinward portions74 of the axial ends68 of the pleats are uncovered byend cap66 and are left exposed. It is preferred that the pleated filter media be dipped into the liquid castable material in the mold by lowering the pleated filter media downwardly until axial ends68 of the pleats are engaged bydam126, and then pushing the pleated filter media further slightly downwardly against the dam such that the dam slightly deforms axial ends68 of the pleats at such engagement point which in turn pushes the pleat sidewalls forming the noted channels slightly laterally to further block the channels and further impede flow of liquid castable material laterally inwardly towardsinner pleat tips36.Trough122 is bounded by anouter perimeter126 and aninner perimeter128.Outer perimeter126 oftrough122 is greater thanouter perimeter30 of the filter element defined byouter pleat tips32.Inner perimeter128 oftrough122 is less thanouter perimeter30 of the filter element.Inner perimeter128 oftrough122 is greater thaninner perimeter34 of the filter element defined byinner pleat tips36. The noted second perimeter of the mold atannular dam126 is less than or equal toinner perimeter128 oftrough122.

As noted, the method for moldingend cap66 ontopleated filter media26 involves dipping axial ends68 of the pleats into liquid castable material intrough122 ofmold120, and engaging axial ends68 of the pleats againstdam126 at a location betweenouter pleat tips32 andinner pleat tips36 such thatdam126 impedes flow of the liquid castable material laterally inwardly towardsinner pleat tips36.Trough122 is provided and aligned such that it partially spans axial ends68 of the pleats such that the laterallyoutward portions72 of the axial ends of the pleats are covered by the liquid castable material during dipping, but not the laterallyinward portions74 of the axial ends of the pleats. Further in accordance with the described method, laterally inward flow of the liquid castable material is impeded along the axial ends of the pleats towardinner pleat tips36 by providing and aligningdam126 to engageaxial ends68 of the pleats betweenouter pleat tips32 andinner pleat tips36 such that laterallyoutward portions72 of the axial ends of the pleats are covered byend cap66, and laterallyinward portions74 of the axial ends of the pleats are uncovered byend cap66 and are left exposed.Trough122 andfilter element22 are aligned during the noted dipping such thatouter perimeter126 oftrough122 circumscribesouter perimeter30 of the filter element defined byouter pleat tips32, andinner perimeter128 oftrough122 circumscribesinner perimeter26 of the filter element defined byinner pleat tips36.

FIG. 6 shows an alternate embodiment whereinoutlet flow tube90a has an outer section90b of reduced diameter to accommodate engine compartment size and location requirements, yet maintaining an increased diameterinner section90c maintaining the increased diameter andperimeter flow passage56 including axial fluid flow at58 and the extra axial fluid flow at59,FIGS. 2 and 6. The spacing ofaxial end wall88 ofhousing section42 from axial ends68 of the filter media pleats provides aplenum130 accommodating the extra flow and reducing restriction.

The described filter construction was developed for air filters, though may be used for other fluids such as liquid. In the disclosed embodiment, fluid to be filtered flows laterally inwardly through the filter media from the outer perimeter to the inner perimeter and then flows axially in the hollow interior, such thatflow passage56 is an outlet flow passage. Alternatively, fluid to be filtered may flow axially inhollow interior38 and then flow laterally outwardly through the filter media from the inner perimeter to the outer perimeter, in whichcase flow passage56 is the inlet flow passage. In another alternative, fluid flow to or fromaxial end64 of the filter element and through the media may be axial or a combination of axial and radial, for example as in the noted incorporated '076 patent. In other alternatives, metal end caps are used instead of urethane end caps, or various combinations of materials are used for the end caps. In further alternatives, outer section90b,FIG. 7, of the flow tube has a larger inner diameter thaninner section90c.

Present Invention

During further development, it has been found that there are some applications where enhanced structural integrity is desired in the end cap area at66, for example wet conditions, heavy load conditions, vibration, and the like. There are also circumstances where cost reduction is desired. There are also circumstances where even further sealing is desired.

FIGS. 7-11 are likeFIGS. 2-6, respectively, and use like references numerals where appropriate to facilitate understanding.Filter element22 is provided bypleated filter media26 having a plurality ofpleats28 in a closed loop having anouter perimeter30 defined by a plurality ofouter pleat tips32, and aninner perimeter34 defined by a plurality ofinner pleat tips36, and having ahollow interior38 extending alongaxis40. Fluid flows axially inhollow interior38 as shown atarrow58. The filter element has first and second axial ends62 and64. The first axial end is open and provides anaxial flow passage57 therethrough alongaxis40 communicating withhollow interior38. A resilientlycompressible end cap200 at the open axial end covers inner andouter pleat tips36 and32 and spans radially along axial ends68 of the pleats between inner andouter perimeters34 and30. Aflow tube202 communicates withhollow interior38 and extends alongaxial flow passage57 and engagesend cap200.Flow tube202 atengagement204 withend cap200 has aninner perimeter206 greater thaninner perimeter34 defined byinner pleat tips36.Inner perimeter206 offlow tube202 atengagement204 withend cap200 is less thanouter perimeter30 defined byouter pleat tips32.

End cap200 has afirst section208 extending radially inwardly fromouter perimeter30 defined byouter pleat tips32, and has asecond section210 extending radially outwardly frominner perimeter34 defined byinner pleat tips36. First andsecond sections208 and210 meet at a junction defining a step at204 facing radially inwardly toward and engagingflow tube202. The step at204 has a first axial length.Flow tube202 has an innertubular portion212 extending axially alongstep204.Tubular portion212 has an inneraxial end214 facing the first axial end of the filter element at axial ends68 of the pleats and separated therefrom bysection210 ofend cap200.Flow tube202 has aflange portion216 extending radially fromtubular portion212 and facing the first axial end of the filter element at axial ends68 of the pleats and axially spaced from inneraxial end214 oftubular portion212 by a second axial length which is less than the noted first axial length, to thus provide axial compression ofend cap200 including ataxial seal region218.End cap200 has a first axial thickness atfirst section208 atouter perimeter30, a second axial thickness atfirst section208 atstep204, a third axial thickness atsecond section210 atstep204, and a fourth axial thickness atsecond section210 atinner perimeter34. The noted second axial thickness is greater than the noted third axial thickness. The noted first axial thickness is greater than the noted fourth axial thickness. The noted first axial thickness is less than the noted second axial thickness. The noted third and fourth axial thicknesses are substantially the same.

In one embodiment, the filter element includes in combination the notedsecond end cap76 at the secondaxial end64 of the filter element at axial ends78 of the pleats and covering inner andouter pleat tips36 and32 and spanning radially between inner andouter perimeters34 and30, and also spanninghollow interior38 and closing the second axial end of the filter element. The filter element is preferably contained in the noted housing having anend wall220 facing the first axial end of the filter element.Flow tube202 is part ofend wall220.

Flow tube202 engagesend cap200 at first, second and third engagement seals218,222 and224, respectively, to provide triple sealing ofend cap200 to flowtube202.Seals218 and224 are axial seals, and seal222 is a radial seal. Firstinner portion212 offlow tube202 extends axially alongstep204 and engages the step to form the noted secondradial seal222.Tubular portion212 has the noted inneraxial end214 axially engagingend cap200 at the notedsecond section210 and forming the noted thirdaxial seal224.Flow tube202 has the notedflange portion216 extending radially fromtubular212 and axially spaced outwardly of inneraxial end214 and axially engagingend cap200 atfirst section208 and providing the noted firstaxial seal218. Secondradial seal222 is axially between first and thirdaxial seals218 and224.

FIG. 10 shows amold120 for molding or pottingend cap200 ontopleated filter media26 of the filter element. The mold has atrough122 as above. The mold has aninsert230 similar to insert124 but withupstanding dam232 atinner pleat tips36 atinner perimeter34.

FIG. 11 shows an alternate embodiment whereinoutlet flow tube202a has anouter section201a of reduced diameter to accommodate engine compartment size and location requirements, yet maintaining an increasedinner diameter section203a, as in FIG.6. The spacing ofaxial end wall220 of the housing from axial ends68 of the filter media pleats provides thenoted plenum130.End cap200a has the noted first andsecond sections208a and210a.End cap200a covers the inner andouter pleat tips36 and32 and spans radially between the inner andouter perimeters34 and30. The end cap provides the noted triple sealing ataxial seals218a and224a and atradial seal222a.

As shown in comparingFIGS. 3,4,8,9, the present construction seals the axial ends68 of the pleats solely withurethane end cap200, or200a, and eliminates reliance uponhot melt110 for sealing purposes. This eliminates the adhesive component in the design ofFIGS. 3,4, and simplifies the production process, reducing cost. In the present construction ofFIGS. 8,9, the axial ends68 of thepleats28 are sealed with thesame urethane200, or200a, used to pot the element, rather than a combination ofhot melt110 andurethane66 as inFIGS. 3,4. The present construction also eliminates reliance upon the interface between theglue110, the filter media of thepleats28, and theurethane66 to prevent contaminants from passing to the clean side of the filter. The present construction further facilitates concentricity of the closed loop configuration. The present construction further enhances structural integrity, particularly in wet conditions, heavy load conditions, and vibration conditions.

FIG. 12 shows a further embodiment and uses like reference numerals from above where appropriate to facilitate understanding.End cap200b hasfirst section240 extending radially inwardly from theouter perimeter30 defined byouter pleat tips32, and has asecond section242 extending radially inwardly fromfirst section240. First andsecond sections240 and242 meet at a junction defining astep204b.Flow tube202b communicates withhollow interior38 and extends alongaxial flow passage57.Flow tube202b has an inner tubular portion212b extending alongstep204b and radially engaging the step to form aradial seal222 therewith.Flow tube202b has the notedflange portion216 extending radially outwardly from tubular portion212b and axially spaced from firstaxial end68 of the filter element byfirst section240 ofend cap200b therebetween.Flange portion216 engagesfirst section240 ofend cap200b atengagement point218b to form an axial seal therewith. Tubular portion212b has an inneraxial end244 axially facingfirst end68 of the filter element.Second section242 ofend cap200b is axially between inneraxial end244 of tubular portion212b and firstaxial end68 of the filter element.Second section242 ofend cap200b extends radially inwardly fromfirst section240 of the end cap all the way toinner perimeter34 defined byinner pleat tips36.End cap200b covers inner andouter pleat tips36 and32 and spans radially between inner andouter perimeters34 and30. Inneraxial end244 of tubular portion212b is axially spaced fromsecond section242 ofend cap200b by anaxial gap246 therebetween. This may be desired in some applications to protect against excessive axial compression or axial crushing. For example, it may be desired to protect the pleat ends at68 from the line of axial force otherwise provided by the annulus atinner end244 of the flow tube, with or without adhesive orhot melt110 between the pleats.

FIG. 13 shows a further embodiment and uses like reference numerals from above where appropriate to facilitate understanding.End cap200c has afirst section250 extending radially inwardly from theouter perimeter30 defined byouter pleat tips32, and has asecond section252 extending radially inwardly fromfirst section250. First andsecond sections250 and252 meet at a junction defining astep204c.Flow tube202c communicates withhollow interior38 and extends alongaxial flow passage57.Flow tube202c has atubular portion212c extending axially alongstep204c and radially engaging the step to form a radial seal therewith.Flow tube202c hasflange portion216 extending radially outwardly fromtubular portion212c and axially spaced from firstaxial end68 of the filter element by thefirst section250 ofend cap200c therebetween.Flange portion216 axially engagesfirst section250 ofend cap200c atengagement point218c to form an axial seal therewith.Tubular portion212c has inneraxial end214 axially facingfirst end68 of the filter element.Second section252 ofend cap200c is axially between inneraxial end214 oftubular portion212c andfirst end68 of the filter element.Second section252 ofend cap200c extends radially inwardly fromfirst section250 only partially towardsinner perimeter34 defined byinner pleat tips36 and does not coverinner pleat tips36. This embodiment may be desirable in instances where the additional migration or flow at59 is desired. This embodiment may also be desirable where additional flow of potting material into the pleat ends and between the wall segments of the pleats is desired. For example, the wider the radial extent of the end cap alongaxial end68 of the filter element, the greater the axially leftward migration of the molten potting material into and between the pleats. This may be desirable for enhanced sealing including greater interface area with the adhesive orhot melt110 between the pleats. Inneraxial end214 oftubular portion212c may axially engagesecond section252 ofend cap200c as shown inFIG. 13 to form a secondaxial seal224 therewith as in FIG.7. Alternatively, inneraxial end214 may be spaced axially rightwardly ofsecond section252 of the end cap by an axial gap therebetween as ataxial gap246 in FIG.12.

FIG. 14 shows a further embodiment including afilter element260 including a closed loopfilter media member262 having ahollow interior264 extending along a givenaxis266, and which may also include anouter prefilter member268 such as open cell foam. Fluid flows axially inhollow interior264. The filter element has first and second axial ends270 and271. Firstaxial end270 is open and provides anaxial flow passage272 therethrough alongaxis266 communicating withhollow interior264. A resilientlycompressible end cap274 is provided at firstaxial end270. A flow tube as shown in dashed line at276 and which is comparable to flowtube202, communicates withhollow interior264 and extends alongaxial flow passage272.Flow tube276 has atubular portion278, comparable totubular portion212, engagingend cap274 and forming a seal therewith, comparable to seal218 and/or222 and/or224.Tubular portion278 is cylindrical.Filter media member262 is non-cylindrical. In one embodiment, the filter media member is elliptical, such as oval, racetrack shaped, or the like.End cap274 has afirst section280 extending radially inwardly from anouter perimeter282, and hassecond section284 extending radially inwardly fromfirst section280 to aninner perimeter286. First andsecond sections280 and284 are comparable to first andsecond sections240 and242 and to first andsecond sections250 and252. First andsecond sections280 and284 meet at a junction defining astep288, comparable tosteps204,204b,204c.First section280 has the notedouter perimeter282, and has aninner perimeter290 atstep288.Second section284 has anouter perimeter292 atstep288, and has the notedinner perimeter286 communicating withhollow interior264.Outer perimeter282 offirst section280 is non-cylindrical.Inner perimeter290 offirst section280 is cylindrical. Step288 is cylindrical.Outer perimeter292 ofsecond section284 is cylindrical. Cylindricaltubular portion278 engagesend cap274 atcylindrical step288, comparable to the above noted engagement ofcylindrical portions212,212b,212c withsteps204,204b,204c.Inner perimeter286 ofsecond section284 is non-cylindrical.Filter media member262 andouter perimeter282 offirst section280 ofend cap274 are elliptical and have a radially extending major axis (left-right in FIG.14), and a radially extending minor axis (up/down in FIG.14). The radial extension offirst section280 ofend cap274 along the major axis betweenouter perimeter282 offirst section280 ofend cap274 and step290 is greater than the radial extension offirst section280 ofend cap274 along the minor axis betweenouter perimeter282 offirst section280 ofend cap274 andstep288. The radial extension ofsecond section284 ofend cap274 along the minor axis betweenstep288 andinner perimeter286 ofsecond section284 ofend cap274 is greater than the radial extension of thesecond section284 ofend cap274 along the major axis betweenstep288 andinner perimeter286 ofsecond section284 ofend cap274. In the embodiment shown,filter media member262 is provided by pleated filter media having a plurality of pleats as above in a closed loop having an outer perimeter defined by a plurality of outer pleat tips, comparable topleat tips32, and an inner perimeter defined by a plurality of inner pleat tips, comparable topleat tips36, the loop having the notedhollow interior264 extending along the noted givenaxis266. Other types of filter media may be used, including non-pleated media. The disclosed elliptical filter design may be used in implementations where it is desired to have an elliptical filter and to maximize the inlet or outlet diameter of the filter or match specifications requiring cylindrical inlet or outlet flow tubes.

It is recognized that various equivalents, alternatives and modifications are possible within the scope of the appended claims.

Claims (34)

1. A filter element comprising pleated filter media having a plurality of pleats in a closed loop having an outer perimeter defined by a plurality of outer pleat tips, and an inner perimeter defined by a plurality of inner pleat tips, said loop having a hollow interior extending along a given axis, wherein fluid flows axially in said hollow interior, said filter element having first and second axial ends, said first axial end being open and providing an axial flow passage therethrough along said axis communicating with said hollow interior, a resiliently compressible end cap at said first axial end covering said inner and outer pleat tips and spanning radially between said inner and outer perimeters, a flow tube communicating with said hollow interior and extending along said axial flow passage and engaging said end cap, wherein said flow tube at said engagement with said end cap has an inner perimeter greater than said inner perimeter defined by said inner pleat tips, and comprising in combination a second end cap at said second axial end of said filter element covering said inner and outer pleat tips and spanning radially between said inner and outer perimeters and also spanning said hollow interior and closing said second axial end of said filter element.

2. The filter element according toclaim 1 wherein said inner perimeter of said flow tube at said engagement with said end cap is less than said outer perimeter defined by said outer pleat tips.

3. The filter element according toclaim 2 wherein said end cap has a first section extending radially inwardly from said outer perimeter defined by said outer pleat tips, and has a second section extending radially outwardly from said inner perimeter defined by said inner pleat tips, said first and second sections meeting at a junction defining a step facing radially toward and engaging said flow tube.

4. The filter element according toclaim 3 wherein said step has a first axial length, said flow tube has a tubular portion extending axially along said step, said tubular portion having an inner axial end axially facing said first axial end of said filter element, and said flow tube has a flange portion extending radially from said tubular portion and facing said first axial end of said filter element and axially spaced from said inner axial end of said tubular portion by a second axial length less than said first said axial length.

5. The filter element according toclaim 3 wherein said end cap has a first axial thickness at said first section at said outer perimeter defined by said outer pleat tips, a second axial thickness at said first section at said step, a third axial thickness at said second section at said step, and a fourth axial thickness at said second section at said inner perimeter defined by said inner pleat tips, and wherein said second axial thickness is greater than said third axial thickness.

6. The filter element according toclaim 5 wherein said first axial thickness is greater than said fourth axial thickness.

7. The filter element according toclaim 5 wherein said first axial thickness is less than said second axial thickness.

8. The filter element according toclaim 5 wherein said third and fourth axial thicknesses are substantially the same.

9. The filter element according toclaim 1 comprising a housing containing said filter element, said housing having an end wall axially facing said first axial end of said filter element, and wherein said flow tube is part of said end wall.

10. The filter element according toclaim 1 wherein fluid flows laterally radially through said filter element between said outer and inner perimeters, and flows axially in said hollow interior.

11. A filter element comprising a closed loop filter media member having a hollow interior extending along a given axis, wherein fluid flows axially in said hollow interior, said filter element having first and second axial ends, said first axial end being open and providing an axial flow passage therethrough along said axis communicating with said hollow interior, a resiliently compressible end cap at said first axial end, a flow tube communicating with said hollow interior and extending along said axial flow passage, said flow tube having a tubular portion engaging said end cap and forming a seal therewith, said tubular portion being cylindrical, said filter media member being non-cylindrical.

12. The filter element according toclaim 11 wherein said filter media member is elliptical.

13. The filter element according toclaim 11 wherein said end cap has a first section extending radially inwardly from an outer perimeter, and has a second section extending radially inwardly from said first section to an inner perimeter, said first and second sections meeting at a junction defining a step, said first section having said outer perimeter and having an inner perimeter at said step, said second section having an outer perimeter at said step and having said inner perimeter communicating with said hollow interior, said outer perimeter of said first section being non-cylindrical, said inner perimeter of said first section being cylindrical, said step being cylindrical, said outer perimeter of said second section being cylindrical.

14. The filter element according toclaim 13 wherein said cylindrical tubular portion engages said end cap at said cylindrical step.

15. The filter element according to claim wherein said inner perimeter of said second section is non-cylindrical.

16. The filter element according toclaim 13 wherein said filter media member and said outer perimeter of said first section of said end cap are elliptical and have a radially extending major axis and a radially extending minor axis, wherein the radial extension of said first section of said end cap along said major axis between said outer perimeter of said first section of said end cap and said step is greater than the radial extension of said first section of said end cap along said minor axis between said outer perimeter of said first section of said end cap and said step, and wherein the radial extension of said second section of said end cap along said minor axis between said step and said inner perimeter of said second section of said end cap is greater than the radial extension of said o second section of said end cap section along said major axis between said step and said inner perimeter of said second section of said end cap.

17. The filter element according toclaim 11 wherein said filter media member comprises pleated filter media having a plurality of pleats in a closed loop having an outer perimeter defined by a plurality of outer pleat tips, and an inner perimeter defined by a plurality of inner pleat tips, said loop having said hollow interior extending along said given axis.

18. A filter comprising pleated filter media having a plurality of pleats in a closed loop having an outer perimeter defined by a plurality of outer pleat tips, and an inner perimeter defined by a plurality of inner pleat tips, said loop having a hollow interior extending along a given axis, wherein fluid flows axially in said hollow interior, said filter having first and second axial ends, said first axial end being open and providing an axial flow passage therethrough along said axis communicating with said hollow interior, a resiliently compressible first end cap at said first axial end covering said inner and outer pleat tips and spanning radially between said inner and outer perimeters, a second end cap at said second axial end of said filter covering said inner and outer pleat tips and spanning radially between said inner and outer perimeters and also spanning said hollow interior and closing said second axial end of said filter, and an outer liner circumscribing said filter.

19. The filter according toclaim 18 wherein said outer liner circumscribes said filter at at least one of said pleated filter media and said first end cap.

20. The filter according toclaim 19 wherein said outer liner circumscribes said filter at said pleated filter media.

21. The filter according toclaim 20 wherein said outer liner circumscribes the entire said pleated filter media from said first axial end to said second axial end.

22. The filter according toclaim 19 wherein said outer liner circumscribes said filter at said first end cap.

23. The filter according toclaim 22 wherein said outer liner circumscribes a portion of said first end cap.

24. The filter according toclaim 19 wherein said outer liner circumscribes said filter at both of said pleated filter media and said first end cap.

25. The filter according toclaim 24 wherein said outer liner is a single one-piece member.

26. The filter according toclaim 18 wherein said first end cap has a first section extending radially inwardly from said outer perimeter defined by said outer pleat tips, and has a second section extending radially outwardly from said inner perimeter defined by said inner pleat tips, said first and second sections meeting at a junction defining a step.

27. The filter according toclaim 26 wherein said first end cap has a first axial thickness at said first section at said outer perimeter defined by said outer pleat tips, a second axial thickness at said first section at said step, a third axial thickness at said second section at said step, and a fourth axial thickness at said second section at said inner perimeter defined by said inner pleat tips, and wherein said second axial thickness is greater than said third axial thickness.

28. The filter according toclaim 27 wherein said first axial thickness is greater than said fourth axial thickness.

29. The filter according toclaim 27 wherein said first axial thickness is less than said second axial thickness.

30. The filter according toclaim 27 wherein said third and fourth axial thicknesses are substantially the same.

31. The filter according toclaim 18 wherein said first end cap is configured to receive a flow tube communicating with said hollow interior and extending along said axial flow passage and engaging said first end cap, wherein said flow tube at said engagement with said first end cap has an inner perimeter greater than said inner perimeter defined by said inner pleat tips, wherein said first end cap bears radially between said outer liner and said flow tube.

32. The filter according toclaim 31 wherein said outer liner has at least a portion circumscribing said filter at and extending axially into said first end cap.

33. The filter according toclaim 18 wherein said outer liner has a first section circumscribing said pleated filter media at said outer pleat tips, and a second section extending into said first end cap.

34. The filter according toclaim 33 wherein said outer liner is a unitary one-piece member, and said second section extends integrally from said first section.

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