US5543047A — Filter with over-laid pleats in intimate contact

Claim 1

Independent Claim 143 words

A filter comprising: a cylindrical filter element having a longitudinal axis, first and second end surfaces, and a plurality of longitudinal pleats, each of the pleats having a pair of legs, each of the legs having a first and a second surface, the pleats being in a laid-over state in which the first surface of one leg of one pleat is in intimate contact with the first surface of an adjoining leg of said one pleat and the second surface of said one leg is in intimate contact with the second surface of an adjoining leg of an adjacent pleat over substantially the entire height of each leg and over a continuous region extending for at least approximately 50% of the axial length of the filter element; and a first impervious end cap connected to the first end surface of the filter element.

Claim 2

Dependent Claim 143 words

A filter comprising: a cylindrical filter element having a longitudinal axis, first and second end surfaces, and a plurality of longitudinal pleats, each of the pleats having a pair of legs, each of the legs having a first and a second surface, the pleats being in a laid-over state in which the first surface of one leg of one pleat is in intimate contact with the first surface of an adjoining leg of said one pleat and the second surface of said one leg is in intimate contact with the second surface of an adjoining leg of an adjacent pleat over substantially the entire height of each leg and over a continuous region extending for at least approximately 50% of the axial length of the filter element; and a first impervious end cap connected to the first end surface of the filter element.

Claim 3

Dependent Claim 59 words

A filter as claimed in claim 1 wherein the filter element comprises a pleated composite comprising a filter medium having an upstream side and a downstream side and at least one of an upstream drainage layer disposed on the upstream side of the filter medium and a downstream drainage layer disposed on the downstream side of the filter medium.

Claim 4

Dependent Claim 21 words

A filter as claimed in claim 2 wherein the upstream and downstream drainage layers have approximately the same edgewise flow resistance.

Claim 5

Dependent Claim 18 words

A filter as claimed in claim 2 wherein at least one of the drainage layers comprises a mesh.

Claim 6

Dependent Claim 31 words

A filter as claimed in claim 4 wherein the mesh comprises an extruded polymeric mesh having strands oriented so as not to nest when the pleats are in the laid-over state.

Claim 7

Dependent Claim 75 words

A filter as claimed in claim 5 wherein the mesh comprises a first set of strands disposed opposite a surface of the filter medium and a second set of strands separated from the surface of the filter medium by the first set of strands, wherein the strands in the second set of strands extend along lines forming an angle between 0 degrees and 90 degrees with respect to the longitudinal axis of the filter element.

Claim 8

Dependent Claim 21 words

A filter as claimed in claim 2 wherein at least one of the drainage layers comprises a woven or nonwoven fabric.

Claim 9

Dependent Claim 20 words

A filter as claimed in claim 7 wherein at least one of the drainage layers comprises a nonwoven polyester fabric.

Claim 10

Dependent Claim 25 words

A filter as claimed in claim 1 wherein the two legs of each pleat have differing heights prior to being formed into a laid-over state.

Claim 11

Dependent Claim 40 words

A filter as claimed in claim 1 wherein gaps between opposing surfaces of the pleats adjoining a radially inner periphery of the filter element have a height of at most approximately a thickness t of each leg of the pleats.

Claim 12

Dependent Claim 19 words

A filter as claimed in claim 10 wherein the gaps have a height of at most approximately 1/2 t.

Claim 13

Dependent Claim 42 words

A filter as claimed in claim 1 wherein gaps between opposing surfaces of the pleats adjoining a radially outer periphery of the filter element have a height of at most approximately four times a thickness t of each leg of the pleat.

Claim 14

Dependent Claim 19 words

A filter as claimed in claim 12 wherein the gaps have a height of at most approximately 2 t.

Claim 15

Dependent Claim 29 words

A filter as claimed in claim 1 wherein the pleats extend in an arcuate manner from a radial inner periphery towards a radial outer periphery of the filter element.

Claim 16

Dependent Claim 60 words

A filter as claimed in claim 1 wherein the filter element comprises a pleated composite including a filter medium and an insert, the insert being sealed to the first end cap and having an axial width less than the axial length of the filter element and a higher affinity for sealing to the first end cap than the filter medium.

Claim 17

Dependent Claim 18 words

A filter as claimed in claim 15 wherein the insert has an axial width of approximately 0.5 inches.

Claim 18

Dependent Claim 18 words

A filter as claimed in claim 15 wherein the first end cap and the insert comprise a fluoropolymer.

Claim 19

Dependent Claim 23 words

A filter as claimed in claim 1 wherein each pleat has a smooth radius along a radial outer periphery of the filter element.

Claim 20

Dependent Claim 25 words

A filter as claimed in claim 1 wherein the continuous region extends for at least approximately 75% of the axial length of the filter element.

Claim 21

Dependent Claim 25 words

A filter as claimed in claim 18 wherein the continuous region extends for at least approximately 95% of the axial length of the filter element.

Claim 22

Dependent Claim 53 words

A filter as claimed in claim 1 wherein each pleat has a height of at least approximately 80% of h.sub.max =(D.sup.2 -d.sup.2)/[4(d+2 t)] wherein D is an outer diameter of the filter element, d is an inner diameter of the filter element, and t is a thickness of each leg of the pleat.

Claim 23

Dependent Claim 22 words

A filter as claimed in claim 21 wherein each pleat has a height of at least approximately 90% of h max .

Claim 24

Dependent Claim 19 words

A filter as claimed in claim 1 wherein the filter element includes a filter medium comprising a porous film.

Claim 25

Dependent Claim 19 words

A filter as claimed in claim 1 wherein the filter element includes a filter medium comprising a fibrous material.

Claim 26

Dependent Claim 19 words

A filter as claimed in claim 1 including a retaining member for retaining the pleats in the laid-over state.

Claim 27

Dependent Claim 27 words

A filter as claimed in claim 25 wherein the retaining member comprises a cage disposed around the filter element and having openings for the passage of fluid.

Claim 28

Dependent Claim 26 words

A filter as claimed in claim 25 wherein the retaining member comprises a wrap member helically wrapped around the filter element in a plurality of turns.

Claim 29

Dependent Claim 59 words

A filter as claimed in claim 27 wherein the pleats have peaks defining an outer surface of the filter element, and a helical gap is formed between adjacent turns of the wrap member, the total area of the helical gap being less than about one-half of the total area of the surface defined by the peaks of the pleats.

Claim 30

Dependent Claim 35 words

A filter as claimed in claim 28 wherein the total area of the helical gap is approximately 6% to approximately 30% of the total area of the surface defined by the peaks of the pleats.

Claim 31

Dependent Claim 43 words

A filter as claimed in claim 1 wherein the pleated filter element includes a filter medium, first and second drainage layers disposed on opposite sides of the filter medium, and a cushioning layer disposed between the first drainage layer and the filter medium.

Claim 32

Dependent Claim 20 words

A filter as claimed in claim 30 wherein the cushioning layer comprises a material smoother than the first drainage layer.

Claim 33

Dependent Claim 23 words

A filter as claimed in claim 30 wherein the cushioning layer comprises a material having greater resistance to abrasion than the filter medium.

Claim 34

Dependent Claim 39 words

A filter as claimed in claim 1 further comprising a second impervious end cap attached to the second end surface of the filter element, at least one of the first and second end caps being an open end cap.

Claim 35

Dependent Claim 30 words

A filter as claimed in claim 33 wherein the end caps are sealed to the end surfaces of the filter element to prevent fluid from passing through the end surfaces.

Claim 36

Dependent Claim 78 words

A filter element as claimed in claim 1 wherein the filter element includes a filter medium and first and second drainage layers disposed on opposite sides of the filter medium and wherein a height h of each pleat is greater than (D-d)/2 and less than h max =(D 2 -d 2 )/[4(d+2 t)] where D and d are an outer diameter and an inner diameter, respectively, of the filter element and t is a thickness of each leg.

Claim 37

Dependent Claim 34 words

A filter element as claimed in claim 35 wherein each drainage layer comprises an extruded mesh, each mesh having strands oriented so as not to nest when the pleats are in the laid-over state.

Claim 38

Dependent Claim 22 words

A filter element as claimed in claim 36 wherein each mesh has a mesh count of at least 10 strands per inch.

Claim 39

Dependent Claim 86 words

A filter as claimed in claim 1 wherein the filter element comprises a pleated composite including a filter medium having an upstream side and a downstream side, a first extruded mesh layer disposed on the upstream side and a second extruded mesh layer disposed on the downstream side of the filter medium, and first and second cushioning layers disposed between the filter medium and the first and second mesh layers, respectively, each cushioning layer comprising a material having greater resistance to abrasion than the filter medium.

Claim 40

Dependent Claim 83 words

A filter as claimed in claim 38 wherein gaps between opposing surfaces of the pleats adjoining a radially inner periphery of the filter element have a height of at most approximately a thickness t of each leg of the pleats, gaps between opposing surfaces of the pleats adjoining a radially outer periphery of the filter element have a height of at most approximately 4 t, and the continuous region extends for at least approximately 95% of the axial length of the filter element.

Claim 41

Dependent Claim 25 words

A filter as claimed in claim 38 wherein the two legs of each pleat have differing heights prior to being formed into a laid-over state.

Claim 42

Dependent Claim 43 words

A filter as claimed in claim 38 wherein each pleat has a height of at least approximately 80% of h.sub.max =(D.sup.2 -d.sup.2)/[4(d+2 t)] wherein D is an outer diameter of the filter element, and d is an inner diameter of the filter element.

Claim 43

Dependent Claim 112 words

A filter as claimed in claim 1 wherein the filter element comprises a pleated composite including a filter medium having an upstream side and a downstream side, a first polymeric mesh layer disposed on the upstream side and a second polymeric mesh layer disposed on the downstream side of the filter medium, and a nonwoven fabric cushioning layer disposed between the filter medium and the first mesh layer, the filter medium comprising a nonwoven fabric substrate on the downstream side of the filter medium and a layer of glass fibers supported on the substrate on the upstream side of the filter medium, the cushioning layer protecting the glass fiber layer from abrasion.

Claim 44

Dependent Claim 58 words

A filter as claimed in claim 1 wherein the filter element comprises a pleated composite including a filter medium comprising a fibrous sheet having an upstream side and a downstream side, a first extruded polymeric mesh layer disposed on the upstream side and a second extruded polypropylene mesh layer disposed on the downstream side of the filter medium.

Claim 45

Dependent Claim 15 words

A filter as claimed in claim 43 wherein the filter medium comprises a melt-blown medium.

Claim 46

Dependent Claim 96 words

A filter as claimed in claim 1 wherein the filter element comprises a pleated composite comprising a filter medium having an upstream side and a downstream side, a first extruded mesh layer disposed on the upstream side, and a second extruded mesh layer disposed on the downstream side of the filter medium, one of the mesh layers defining the first surface of each leg and the other of the mesh layers defining the second surface of each leg, each mesh having strands oriented so as not to nest when the pleats are in the laid-over state.

Claim 47

Dependent Claim 69 words

A filter as claimed in claim 1 wherein the filter element comprises a pleated composite comprising a filter medium including a porous membrane having an upstream and a downstream side, a first drainage layer of a woven or non-woven fabric disposed on the upstream side of the porous membrane, and a second drainage layer of a woven or non-woven fabric disposed on the downstream side of the porous membrane.

Claim 48

Dependent Claim 15 words

A filter as claimed in claim 46 wherein the porous membrane comprises a polytetrafluoroethylene membrane.

Claim 49

Dependent Claim 15 words

A filter as claimed in claim 46 wherein the porous membrane comprises a nylon membrane.

Claim 50

Dependent Claim 115 words

A filter as claimed in claim 1 wherein the filter element comprises a pleated composite comprising a filter medium and first and second drainage layers on opposite sides of the filter medium, the filter further comprising a wrap member for retaining the pleats in the laid-over state and helically wrapped around the filter element in a plurality of turns with a helical gap being formed between adjacent turns of the wrap member, the pleats having peaks defining an outer surface of the filter element, the total area of the helical gap being approximately 6% to approximately 30% of the total area of the total area of the surface defined by the peaks of the pleats.

Claim 51

Dependent Claim 91 words

A filter as claimed in claim 1 wherein the first end cap comprises a fluoropolymer and wherein the filter element comprises a pleated composite comprising a filter medium having an upstream side and a downstream side, first and second drainage layers disposed on the upstream and downstream sides of the filter medium, and a fluoropolymer insert sealed to the first end cap and having an axial width less than the axial length of the filter element and a greater affinity for sealing to the first end cap than the filter medium.

Claim 52

Dependent Claim 124 words

A filter as claimed in claim 1 wherein the filter element comprises a pleated composite comprising a filter medium having an upstream side and a downstream side, a first extruded mesh layer disposed on the upstream side and a second extruded mesh layer disposed on the downstream side of the filter medium, and a cushioning layer disposed between the filter medium and the first mesh layer and comprising a material having greater resistance to abrasion than the filter medium, each pleat having a height h at least approximately 80% of h.sub.max =(D.sup.2 -d.sup.2)/[4(d+2 t)] wherein D is an outer diameter of the filter element, d is an inner diameter of the filter element, and t is a thickness of each leg of the pleat.

Claim 53

Dependent Claim 17 words

The filter as claimed in claim 1 wherein the impervious end cap comprises an open end cap.

Claim 54

Dependent Claim 17 words

The filter as claimed in claim 1 wherein the impervious end cap comprises a blind end cap.

Claim 55

Dependent Claim 237 words

A filter for separating one or more substances from a fluid flowing therethrough, the filter comprising: a pleated filter element having an interior, a longitudinal axis, first and second end surfaces, and a plurality of longitudinal pleats, wherein each of the pleats has a curved configuration and includes a crown, a root, and a pair of legs and each of the legs has a first surface and a second surface, the legs of each pleat being joined to one another at the crown and joined to a leg of an adjacent pleat at the root and the pleats being in a laid-over state in which the first a surface of one leg on one pleat is in intimate contact with the first surface of an adjoining leg of said one pleat and the second surface of said one leg is in intimate contact with the second surface of an adjoining leg of an adjacent pleat over substantially the entire height of each leg and over a continuous region extending for at least approximately 50 percent of the longitudinal length of the pleated filter element and wherein the pleated filter element comprises at least first and second layers, wherein the second layer comprises a filter medium, and first and second end elements sealingly arranged with the first and second ends, respectively, of the pleated filter element, at least one of the end elements comprising an open end element.

Claim 56

Dependent Claim 237 words

A filter for separating one or more substances from a fluid flowing therethrough, the filter comprising: a pleated filter element having an interior, a longitudinal axis, first and second end surfaces, and a plurality of longitudinal pleats, wherein each of the pleats has a curved configuration and includes a crown, a root, and a pair of legs and each of the legs has a first surface and a second surface, the legs of each pleat being joined to one another at the crown and joined to a leg of an adjacent pleat at the root and the pleats being in a laid-over state in which the first a surface of one leg on one pleat is in intimate contact with the first surface of an adjoining leg of said one pleat and the second surface of said one leg is in intimate contact with the second surface of an adjoining leg of an adjacent pleat over substantially the entire height of each leg and over a continuous region extending for at least approximately 50 percent of the longitudinal length of the pleated filter element and wherein the pleated filter element comprises at least first and second layers, wherein the second layer comprises a filter medium, and first and second end elements sealingly arranged with the first and second ends, respectively, of the pleated filter element, at least one of the end elements comprising an open end element.

Claim 57

Dependent Claim 49 words

The filter of claim 54 wherein the first layer comprises a drainage layer providing even fluid flow to or from the filter medium, the drainage layer having an edgewise flow resistance which provides a lower pressure drop in the drainage layer than the pressure drop across the filter medium.

Claim 58

Dependent Claim 19 words

The filter of claim 54 wherein the first layer comprises a drainage layer including a woven or non-woven sheet.

Claim 59

Dependent Claim 18 words

The filter of claim 54 wherein the first layer comprises a drainage layer including a mesh or screen.

Claim 60

Dependent Claim 39 words

The filter of claim 57 wherein the drainage layer comprises an extruded polymeric mesh having first and second sets of parallel strands, the first set of strands being disposed between the filter medium and the second set of strands.

Claim 61

Dependent Claim 22 words

The filter of claim 58 wherein the first set of strands has a mesh count of at least 10 strands per inch.

Claim 62

Dependent Claim 37 words

The filter of claim 54 wherein the first layer comprises an upstream drainage layer and the pleated filter element further comprises a downstream drainage layer, the filter medium being disposed between the upstream and downstream drainage layers.

Claim 63

Dependent Claim 19 words

The filter of claim 60 wherein the upstream and downstream drainage layers have substantially the same edgewise flow resistance.

Claim 64

Dependent Claim 15 words

The filter of claim 60 wherein the upstream and downstream drainage layers comprise identical materials.

Claim 65

Dependent Claim 15 words

The filter of claim 60 wherein the upstream and downstream drainage layers have different characteristics.

Claim 66

Dependent Claim 17 words

The filter of claim 60 wherein the upstream drainage layer is thicker than the downstream drainage layer.

Claim 67

Dependent Claim 53 words

The filter of claim 54 wherein the first layer comprises a drainage layer and wherein the pleated filter element further comprises a cushioning layer disposed between the drainage layer and the filter medium, the cushioning layer being smoother than the drainage layer and having a higher resistance to abrasion than the filter medium.

Claim 68

Dependent Claim 13 words

The filter of claim 65 wherein the cushioning layer comprises a non-woven fabric.

Claim 69

Dependent Claim 14 words

The filter of claim 64 wherein the filter medium comprises a porous polymeric membrane.

Claim 70

Dependent Claim 13 words

The filter of claim 54 wherein the filter medium comprises a fibrous material.

Claim 71

Dependent Claim 31 words

The filter of claim 68 wherein the filter medium has a graded pore structure including a finer pored region and a coarser pored region disposed upstream from the finer pored region.

Claim 72

Dependent Claim 18 words

The filter of claim 54 wherein the filter medium comprises at least first and second filter medium layers.

Claim 73

Dependent Claim 17 words

The filter of claim 70 wherein the first and second filter medium layers have different filtering characteristics.

Claim 74

Dependent Claim 14 words

The filter of claim 71 wherein the first filter medium layer comprises a prefilter.

Claim 75

Dependent Claim 12 words

The filter of claim 54 wherein the first layer comprises a prefilter.

Claim 76

Dependent Claim 22 words

The filter of claim 54 wherein the filter medium has a removal rating in the range from 0.2 micron to 90 microns.

Claim 77

Dependent Claim 70 words

The filter of claim 54 wherein the first layer comprises a drainage layer and wherein the pleated filter element has an outer diameter (D) and an inner (d) and comprises a pleated composite including the drainage layer and the filter medium and having a thickness (t) and wherein the height of each pleat is greater than (D-d)/2 and is less than h MAX =(D 2 -d 2 )/4(d +2 t).

Claim 78

Dependent Claim 20 words

The filter of claim 75 wherein the height of each pleat is at least 80 percent of h MAX .

Claim 79

Dependent Claim 15 words

The filter of claim 54 wherein there is substantially no empty space between adjacent pleats.

Claim 80

Dependent Claim 45 words

The filter of claim 54 wherein the first and second end elements comprise first and second end caps sealing the first and second ends, respectively, of the pleated filter element, at least one of the first and second end caps comprising an open end cap.

Claim 81

Dependent Claim 22 words

The filter of claim 54 further comprising a retainer around the pleated filter element to maintain the pleats in the laid-over state.

Claim 82

Dependent Claim 22 words

The filter of claim 79 wherein the retainer comprises a wrap including at least one strip helically wrapped around the laid-over pleats.

Claim 83

Dependent Claim 65 words

The filter of claim 54 wherein the first layer comprises an upstream drainage layer and the pleated filter element further comprises a downstream drainage layer, the filter medium being disposed between the upstream and downstream drainage layers and the upstream drainage layer having an edgewise flow resistance providing a lower pressure drop in the upstream drainage layer than the pressure drop across the filter medium.

Claim 84

Dependent Claim 19 words

The filter of claim 81 wherein the upstream and downstream drainage layers have substantially the same edgewise flow resistance.

Claim 85

Dependent Claim 63 words

The filter of claim 82 wherein the pleated filter element has an outer diameter (D) and an inner (d) and comprises a pleated composite including the first and second drainage layers and the filter medium and having a thickness (t) and wherein the height of each pleat is greater than (D-D)/2 and is less than h MAX =(D 2 -d 2 )/4(d+2 t).

Claim 86

Dependent Claim 20 words

The filter of claim 83 wherein the height of each pleat is at least 80 percent of h MAX .

Claim 87

Dependent Claim 100 words

The filter of claim 82 wherein the pleated filter element has an outer diameter (D) and an inner diameter (d) and comprises a pleated composite including the first and second drainage layers and the filter medium and having a thickness (t), wherein the height of each pleat is greater than (D-D)/2 and is less than h MAX =(D 2 -d 2 )/4(d +2 t), and wherein the upstream drainage layer comprises an extruded polymeric mesh having first and second sets of parallel strands, the first set of strands being disposed between the filter medium and the second set of strands.

Claim 88

Dependent Claim 22 words

The filter of claim 85 wherein the first set of strands has a mesh count of at least 10 strands per inch.

Claim 89

Dependent Claim 64 words

The filter of claim 81 wherein the pleated filter element has an outer diameter (D) and an inner diameter (d) and comprises a pleated composite including the first and second drainage layers and the filter medium and having a thickness (t), and wherein the height of each pleat is greater than (D-D)/2 and is less than h MAX =(D 2 -d 2 )/4(d+2 t).

Claim 90

Dependent Claim 40 words

The filter of claim 87 wherein the upstream drainage layer comprises an extruded polymeric mesh having first and second sets of parallel strands, the first set of strands being disposed between the filter medium and the second set of strands.

Claim 91

Dependent Claim 22 words

The filter of claim 88 wherein the first set of strands has a mesh count of at least 10 strands per inch.

Claim 92

Dependent Claim 40 words

The filter of claim 89 wherein the downstream drainage layer comprises an extruded polymeric mesh having first and second sets of parallel strands, the first set of strands being disposed between the filter medium and the second set of strands.

Claim 93

Dependent Claim 20 words

The filter of claim 87 wherein the height of each pleat is at least 80 percent of h MAX .

Claim 94

Dependent Claim 320 words

A filter for separating one or more substances from a fluid flowing therethrough, the filter comprising: a pleated filter element including an outer diameter (D), an inner diameter (d), a longitudinal axis, first and second end surfaces, and a plurality of longitudinal pleats, wherein the pleated filter element comprises a pleated composite having a thickness (t) and including an upstream drainage layer, a downstream drainage layer, and a filter medium disposed between the upstream and downstream drainage layers, the upstream drainage layer having an edgewise flow resistance which provides a lower pressure drop in the upstream drainage layer than the pressure drop across the filter medium, thereby providing an even distribution of fluid along an upstream surface of the filter medium, wherein each of the pleats has a curved configuration and includes a crown, a root, and a pair of legs and each of the legs has a first surface and a second surface, the legs of each pleat being joined to one another at the crown and joined to a leg of an adjacent pleat at the root and the pleats being in a laid-over state in which the first surface of one leg of one pleat is in intimate contact with the first surface of an adjoining leg of said one pleat and the second surface of said one leg is in intimate contact with the second surface of an adjoining leg of an adjacent pleat over substantially the entire height of each leg and over a continuous region extending for at least approximately 95% of the longitudinal length of the pleated filter element, and wherein the height of each pleat is greater than (D-D)/2 and is no greater than (D 2 -d 2 )/4(d+2 t), and first and second end elements sealingly arranged with the first and second ends, respectively, of the pleated filter element, at least one of the end elements comprising an open end element.

Claim 95

Dependent Claim 320 words

A filter for separating one or more substances from a fluid flowing therethrough, the filter comprising: a pleated filter element including an outer diameter (D), an inner diameter (d), a longitudinal axis, first and second end surfaces, and a plurality of longitudinal pleats, wherein the pleated filter element comprises a pleated composite having a thickness (t) and including an upstream drainage layer, a downstream drainage layer, and a filter medium disposed between the upstream and downstream drainage layers, the upstream drainage layer having an edgewise flow resistance which provides a lower pressure drop in the upstream drainage layer than the pressure drop across the filter medium, thereby providing an even distribution of fluid along an upstream surface of the filter medium, wherein each of the pleats has a curved configuration and includes a crown, a root, and a pair of legs and each of the legs has a first surface and a second surface, the legs of each pleat being joined to one another at the crown and joined to a leg of an adjacent pleat at the root and the pleats being in a laid-over state in which the first surface of one leg of one pleat is in intimate contact with the first surface of an adjoining leg of said one pleat and the second surface of said one leg is in intimate contact with the second surface of an adjoining leg of an adjacent pleat over substantially the entire height of each leg and over a continuous region extending for at least approximately 95% of the longitudinal length of the pleated filter element, and wherein the height of each pleat is greater than (D-D)/2 and is no greater than (D 2 -d 2 )/4(d+2 t), and first and second end elements sealingly arranged with the first and second ends, respectively, of the pleated filter element, at least one of the end elements comprising an open end element.

Claim 96

Dependent Claim 28 words

The filter of claim 92 wherein the upstream and downstream drainage layers each comprise a woven or non-woven sheet and the filter medium comprises a porous polymeric membrane.

Claim 97

Dependent Claim 13 words

The filter of claim 93 wherein the porous membrane comprises a nylon membrane.

Claim 98

Dependent Claim 19 words

The filter of claim 93 wherein the upstream and downstream drainage fabric and the porous membrane comprise a fluoropolymer.

Claim 99

Dependent Claim 53 words

The filter of claim 95 wherein the end elements comprise a fluoropolymer and the pleated composite further includes a fluoropolymer insert sealed to each end element and having a width less than the axial length of the filter element and a greater affinity for sealing to the end element than the filter medium.

Claim 100

Dependent Claim 18 words

The filter of any one of claims 92-96 wherein there is substantially no empty space between adjacent pleats.

Claim 101

Dependent Claim 25 words

The filter of claim 92 wherein the upstream and downstream drainage layers comprise a mesh or screen and the filter medium comprises a fibrous material.

Claim 102

Dependent Claim 14 words

The filter of claim 98 wherein the fibrous material comprises a fibrous depth filter.

Claim 103

Dependent Claim 32 words

The filter of claim 99 wherein the fibrous depth filter has a graded pore structure including a finely pored region and a coarsely pored region disposed upstream from the finely pored region.

Claim 104

Dependent Claim 13 words

The filter of claim 99 wherein the fibrous depth filter includes meltblown fibers.

Claim 105

Dependent Claim 16 words

The filter of claim 98 wherein the fibrous material comprises glass fibers disposed on a substrate.

Claim 106

Dependent Claim 45 words

The filter of claim 102 wherein the pleated composite further comprises a cushioning layer disposed between the upstream drainage layer and the glass fibers, the cushioning layer being smoother than the upstream drainage layer and having a higher resistance to abrasion than the fibrous material.

Claim 107

Dependent Claim 44 words

The filter of claim 98 wherein the pleated composite further comprises a cushioning layer disposed between the upstream drainage layer and the fibrous material, the cushioning layer being smoother than the drainage layer and having a higher resistance to abrasion than the filter medium.

Claim 108

Dependent Claim 73 words

The filter of any one of claims 92 and 98-104 wherein the upstream and downstream drainage layers each comprise an extruded mesh having first and second sets of parallel strands, the first set of parallel strands being disposed between the filter medium and the second set of parallel strands, and wherein the first set of parallel strands of the upstream drainage layer has a mesh count of at least ten strands per inch.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1999-08-06	2000-02-05	2000-08-06	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2003-08-06	2004-02-05	2004-08-06	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2007-08-06	2008-02-05	2008-08-06	$7700.00	Window Closed / Lapsed

Filter with over-laid pleats in intimate contact

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