Filter element with mixed pleat height

Abstract

To provide a filter element having mixed pleat heights. [Solution] A filter element having mixed pleat heights, wherein the pleats facing inward and outward have different pleat heights, a filter including the filter element, and a filtration method using the filter element are disclosed. For example, a cylindrical porous filter is disclosed having an inner core and an outer cage, with an annular gap between the inner core and the outer cage, and a cylindrical hollow porous pleated filter element disposed within the annular gap between the inner core and the outer cage, wherein the annular gap is wide.

Description

Background Art

[0001]

[0001] Cross - reference to Related Applications This application claims the benefit of U.S. Provisional Patent Application No. 63 / 395,079, filed on August 4, 2022, which is hereby incorporated by reference in its entirety.

[0002]

[0002] In the art, there is a need for improved pleated filter elements.

[0003]

[0003] The present invention provides to improve at least some of the problems of the prior art. These and other advantages of the present invention will become apparent from the description set forth below.

Summary of the Invention

Means for Solving the Problems

[0004]

[0004] One aspect of the present invention provides a cylindrical porous filter comprising an inner core and an outer cage, having an annular gap between the inner core and the outer cage, and having a cylindrical hollow porous filter element disposed within the annular gap between the inner core and the outer cage, the annular gap having a width, and the cylindrical hollow porous pleated filter element having first and second end faces, and the cylindrical hollow porous pleated filter element comprising a plurality of filter element groups, each of the plurality of filter element groups being alternating with a first filter element subgroup having a first bridge comprising a plurality of longitudinal pleats having a longitudinal pleat height, and a second filter element subgroup having a second bridge comprising at least one longitudinal counterpleat having a longitudinal counterpleat height The filter element subgroup comprises a first bridge and a second bridge, each having a height greater than the width of the annular gap, and the multiple longitudinal pleats in the first filter element subgroup include a first pleat having the greatest height and a second longitudinal pleat having the smallest height, the height of the first longitudinal pleat being within a range of 25% to 35% less than the height of the first bridge, the height of the second longitudinal pleat being within a range of 65% to 75% less than the height of the first bridge, and at least one longitudinal counter pleat in the second filter element subgroup having a longitudinal counter pleat height within a range of 25% to 35% less than the height of the second bridge, and the first bridge, longitudinal pleats, second bridge and at least one longitudinal counter pleat are in a laid-over state.

[0005]

[0005] In one embodiment, each first bridge is Front side First bridge surface and The back side Having a first bridge surface, each of the longitudinal pleats has a pair of longitudinal pleat legs, each of the longitudinal pleat legs has a first longitudinal pleat leg surface and a second longitudinal pleat leg surface, and each second bridge is Front sideThe second bridge surface and The back side Having a second bridge surface, at least one longitudinal counter pleat has a pair of longitudinal counter pleat legs, each of which has a first longitudinal counter pleat leg surface and a second longitudinal counter pleat leg surface, and the first bridge, the longitudinal pleat, the second bridge and at least one longitudinal counter pleat are in an overlapping state, in this state, the longitudinal pleat leg surface of one longitudinal pleat is the longitudinal pleat leg surface of the adjacent leg of that longitudinal pleat, the longitudinal pleat leg surface of the adjacent longitudinal pleat, The back side First bridge surface and Front side The longitudinal counterpleat leg surface of at least one longitudinal counterpleat is in close contact with at least one of the second bridge surfaces, and the longitudinal counterpleat leg surface of at least one longitudinal counterpleat is in close contact with the longitudinal counterpleat leg surface of the adjacent leg of that one longitudinal counterpleat. Front side First bridge surface and The back side It is in close contact with at least one of the second bridge surfaces.

[0006]

[0006] In another embodiment, a method for filtering a fluid is provided, the method comprising the step of passing a fluid through an embodiment of a cylindrical porous filter, the cylindrical porous filter comprising an inner core and an outer cage, having an annular gap between the inner core and the outer cage, and having a cylindrical hollow porous filter element disposed within the annular gap between the inner core and the outer cage, the annular gap having a width, the cylindrical hollow porous pleated filter element having first and second end faces, the cylindrical hollow porous pleated filter element comprising a first filter element subgroup having a first bridge followed by a plurality of longitudinal pleats having a longitudinal pleat height, and alternating with a second filter element subgroup having a second bridge followed by at least one longitudinal counterpleat having a longitudinal counterpleat height The filter element subgroup comprises a first bridge and a second bridge, each having a height greater than the width of the annular gap, and the multiple longitudinal pleats in the first filter element subgroup include a first pleat having the greatest height and a second longitudinal pleat having the smallest height, the height of the first longitudinal pleat being in the range of 25% to 35% less than the height of the first bridge, the height of the second longitudinal pleat being in the range of 65% to 75% less than the height of the first bridge, and at least one longitudinal counterpleat in the second filter element subgroup having a longitudinal counterpleat height in the range of 25% to 35% less than the height of the second bridge, and the first bridge, longitudinal pleats, second bridge and at least one longitudinal counterpleat are in an overlapping state.

[0007]

[0007] In another embodiment, a cylindrical hollow porous pleated filter element is provided, the cylindrical hollow porous pleated filter element comprising a plurality of filter element groups, each of the plurality of filter element groups alternating with a first filter element subgroup having a first bridge consisting of a plurality of longitudinal pleats having a longitudinal pleat height, and a second filter element subgroup having a second bridge consisting of at least one longitudinal counterpleat having a longitudinal counterpleat height. The filter element subgroup comprises a first filter element subgroup having a plurality of longitudinal pleats, the first having the greatest height and the second having the smallest height, the height of the first longitudinal pleat being in the range of 25% to 35% less than the height of the first bridge and the height of the second longitudinal pleat being in the range of 65% to 75% less than the height of the first bridge, and at least one longitudinal counterpleat in the second filter element subgroup having a longitudinal counterpleat height in the range of 25% to 35% less than the height of the second bridge. The present invention provides, for example, the following items: (Item 1) A cylindrical porous filter comprising an inner core and an outer cage, with an annular gap between the inner core and the outer cage, and having a cylindrical hollow porous pleated filter element disposed within the annular gap between the inner core and the outer cage, wherein the annular gap is wide, The cylindrical hollow porous pleated filter element has a first end face and a second end face, and the cylindrical hollow porous pleated filter element comprises a plurality of filter element groups. Each of the plurality of filter element groups comprises a first filter element subgroup having a first bridge followed by a plurality of longitudinal pleats having a longitudinal pleat height, and alternating with a second filter element subgroup having a second bridge followed by at least one longitudinal counter pleat having a longitudinal counter pleat height, Each of the first bridge and the second bridge has a height greater than the width of the annular gap, The plurality of longitudinal pleats in the first filter element subgroup comprises a first pleat having the greatest height and a second longitudinal pleat having the smallest height, wherein the height of the first longitudinal pleat is within a range of 25% to 35% less than the height of the first bridge, and the height of the second longitudinal pleat is within a range of 65% to 75% less than the height of the first bridge. The at least one longitudinal counter pleat in the second filter element subgroup has a longitudinal counter pleat height that is 25% to 35% smaller than the height of the second bridge. A cylindrical porous filter in which the first bridge, the longitudinal pleats, the second bridge, and the longitudinal counter pleats are superimposed. (Item 2) The cylindrical porous filter according to item 1, wherein a first impermeable end cap is connected to the first end face of the filter element. (Item 3) Each of the first bridges has a front first bridge surface and a back first bridge surface. Each of the longitudinal pleats has a pair of longitudinal pleat legs, and each of the longitudinal pleat legs has a first longitudinal pleat leg surface and a second longitudinal pleat leg surface. Each of the aforementioned second bridges has a front second bridge surface and a back second bridge surface, The at least one longitudinal counter pleat has a pair of longitudinal counter pleat legs, each of which has a first longitudinal counter pleat leg surface and a second longitudinal counter pleat leg surface. The first bridge, the longitudinal pleat, the second bridge, and the longitudinal pleat are in an overlapping state, and in this overlapping state, The longitudinal pleat leg surface of one longitudinal pleat is in close contact with at least one of the longitudinal pleat leg surfaces of adjacent legs of the same longitudinal pleat, the longitudinal pleat leg surface of the adjacent longitudinal pleat, the first bridge surface on the back side, and the second bridge surface on the front side. The longitudinal counter pleat leg surface of the longitudinal counter pleat is in close contact with at least one of the longitudinal counter pleat leg surfaces of an adjacent leg of the same longitudinal counter pleat, the first bridge surface on the front side, and the second bridge surface on the back side. A cylindrical porous filter as described in any one of items 1 to 3. (Item 4) A cylindrical porous filter according to any one of items 1 to 3, wherein the first bridge has a height in the range of 10% to 25% greater than the annular gap between the inner core and the outer cage. (Item 5) The cylindrical porous filter according to any one of items 1 to 4, wherein the second bridge has a height in the range of 10% to 25% greater than the annular gap between the inner core and the outer cage. (Item 6) A method for processing a fluid, comprising the step of circulating the fluid through a cylindrical porous filter as described in any one of items 1 to 5. (Item 7) The method according to item 6, comprising the step of circulating the fluid to be filtered through the outer cage, the cylindrical hollow porous pleated filter element, and the inner core. (Item 8) A cylindrical hollow porous pleated filter element comprising multiple filter element groups, Each of the plurality of filter element groups comprises a first filter element subgroup having a first bridge followed by a plurality of longitudinal pleats having a longitudinal pleat height, and alternating with a second filter element subgroup having a second bridge followed by at least one longitudinal counter pleat having a longitudinal counter pleat height, The plurality of longitudinal pleats in the first filter element subgroup have a first pleat having the greatest height and a second longitudinal pleat having the smallest height, A cylindrical hollow porous pleated filter element, wherein the height of the first longitudinal pleat is within a range of 25% to 35% less than the height of the first bridge, the height of the second longitudinal pleat is within a range of 65% to 75% less than the height of the first bridge, and at least one longitudinal counterpleat in the second filter element subgroup is within a range of 25% to 35% less than the height of the second bridge.

Brief Description of the Drawings

[0008] [Figure 1]

[0008] This diagram schematically shows pleats having mixed pleat heights used when manufacturing a filter element according to one aspect of the present invention (for ease of reference, the pleats are shown in an expanded state before compression to form a pleated porous filter element, and the inner core and outer cage are also shown), and shows one aspect of a pleated cylindrical hollow porous filter element disposed in an annular gap between the inner core and the outer cage, the annular gap having a width, and the pleated cylindrical hollow porous filter element comprises a plurality of filter element groups, each of the plurality of filter element groups having a plurality of longitudinal pleats having longitudinal pleat heights The filter element comprises a first filter element subgroup having a first bridge followed by a pleat, each first filter subgroup alternating with a second filter element subgroup having a second bridge followed by at least one longitudinal counterpleat having a longitudinal counterpleat height, the first and second groups of inwardly facing longitudinal pleats (with their tips facing the inner core; height (I)H1-(I)H2) and the at least one outwardly facing longitudinal counterpleat (with its tip facing the outer cage; counterpleat; height (O)H1) having different designs and height patterns (continuously repeating units and asymmetric orientations). [Figure 2A]

[0009] Figure 1 is a photograph showing a filter element. [Figure 2B] Figures 1 and 2A schematically show computed tomography (CT) scans of assembled filter elements with mixed pleat heights, as partially broken in the image. [Figure 2C] This figure shows a partially compressed filter element as shown in Figure 2A. [Figure 3]

[0010] Figure 2B shows a partially cutaway perspective view of a filter according to another aspect of the present invention, which includes a filter element having mixed pleat heights (a filter element that is not completely compressed) as shown in Figure 2B. [Modes for carrying out the invention]

[0009]

[0011] According to one aspect of the present invention, a cylindrical porous filter is provided, comprising an inner core and an outer cage, having an annular gap between the inner core and the outer cage, and having a cylindrical hollow porous filter element disposed within the annular gap between the inner core and the outer cage, the annular gap having a width, and the cylindrical hollow porous pleated filter element having first and second end faces, and the cylindrical hollow porous pleated filter element comprising a plurality of filter element groups, each of the plurality of filter element groups alternating with a first filter element subgroup having a first bridge consisting of a plurality of longitudinal pleats having a longitudinal pleat height, and a second filter element subgroup having a second bridge consisting of at least one longitudinal counterpleat having a longitudinal counterpleat height The filter element subgroup comprises a first bridge and a second bridge, each having a height greater than the width of the annular gap, and the multiple longitudinal pleats in the first filter element subgroup include a first pleat having the greatest height and a second longitudinal pleat having the smallest height, the height of the first longitudinal pleat being in the range of 25% to 35% less than the height of the first bridge, the height of the second longitudinal pleat being in the range of 65% to 75% less than the height of the first bridge, and at least one longitudinal counter pleat in the second filter element subgroup having a longitudinal counter pleat height in the range of 25% to 35% less than the height of the second bridge, and the first bridge, longitudinal pleats, second bridge and at least one longitudinal counter pleat are in an overlapping state.

[0010]

[0012] In another embodiment, a cylindrical hollow porous pleated filter element is provided, the cylindrical hollow porous pleated filter element comprising a plurality of filter element groups, each of which comprises a first filter element subgroup having a first bridge consisting of a plurality of longitudinal pleats having a longitudinal pleat height, and alternating with a second filter element subgroup having a second bridge consisting of at least one longitudinal counterpleat having a longitudinal counterpleat height. In the first filter element subgroup, the multiple longitudinal pleats include a first pleat having the greatest height and a second longitudinal pleat having the smallest height, the height of the first longitudinal pleat being within a range of 25% to 35% less than the height of the first bridge, the height of the second longitudinal pleat being within a range of 65% to 75% less than the height of the first bridge, and at least one longitudinal counterpleat in the second filter element subgroup having a longitudinal counterpleat height within a range of 25% to 35% less than the height of the second bridge.

[0011]

[0013] In another embodiment, a method for filtering a fluid is provided, the method comprising the step of passing a fluid through an embodiment of a cylindrical porous filter, the cylindrical porous filter comprising an inner core and an outer cage, having an annular gap between the inner core and the outer cage, and having a cylindrical hollow porous filter element disposed within the annular gap between the inner core and the outer cage, the annular gap having a width, the cylindrical hollow porous pleated filter element having first and second end faces, the cylindrical hollow porous pleated filter element comprising a first filter element subgroup having a first bridge followed by a plurality of longitudinal pleats having a longitudinal pleat height, and alternating with a second filter element subgroup having a second bridge followed by at least one longitudinal counterpleat having a longitudinal counterpleat height, Each of the first and second bridges has a height greater than the width of the annular gap, and the plurality of longitudinal pleats in the first filter element subgroup have a first pleat having the greatest height and a second longitudinal pleat having the smallest height, the height of the first longitudinal pleat being in the range of 25% to 35% less than the height of the first bridge, the height of the second longitudinal pleat being in the range of 65% to 75% less than the height of the first bridge, and at least one longitudinal counterpleat in the second filter element subgroup has a longitudinal counterpleat height in the range of 25% to 35% less than the height of the second bridge, and the first bridge, longitudinal pleats, second bridge and at least one longitudinal counterpleat are in an overlapping state, preferably the method includes the step of obtaining a filtered fluid.

[0012]

[0014] Embodiments of this method may include an outside-in flow in which the fluid to be filtered flows from the outer cage through the filter element into the inner core, or an inside-out flow in which the fluid flows from the inner core through the filter element into the outer cage.

[0013]

[0015] In a preferred embodiment, the first impermeable end cap is connected to the first end face of the filter element.

[0014]

[0016] In one embodiment, each first bridge is Front side First bridge surface and The back side Having a first bridge surface, each of the longitudinal pleats has a pair of longitudinal pleat legs, each of the longitudinal pleat legs has a first longitudinal pleat leg surface and a second longitudinal pleat leg surface, and each second bridge is Front side The second bridge surface and The back side Having a second bridge surface, at least one longitudinal counter pleat has a pair of longitudinal counter pleat legs, each of which has a first longitudinal counter pleat leg surface and a second longitudinal counter pleat leg surface, and the first bridge, the longitudinal pleat, the second bridge and at least one longitudinal counter pleat are in an overlapping state, in this state, the longitudinal pleat leg surface of one longitudinal pleat is the longitudinal pleat leg surface of the adjacent leg of that longitudinal pleat, the longitudinal pleat leg surface of the adjacent longitudinal pleat, The back side First bridge surface and Front side The longitudinal counterpleat leg surface of at least one longitudinal counterpleat is in close contact with at least one of the second bridge surfaces, and the longitudinal counterpleat leg surface of at least one longitudinal counterpleat is in close contact with the longitudinal counterpleat leg surface of the adjacent leg of that one longitudinal counterpleat. Front side First bridge surface and The back side It is in close contact with at least one of the second bridge surfaces.

[0015]

[0017] In some embodiments, the second (inner) longitudinal pleat leg surface of one longitudinal pleat is in close contact with the second (inner) longitudinal pleat leg surface of an adjacent leg of the same longitudinal pleat, and the first (outer) longitudinal pleat leg surface of one longitudinal pleat is The back side The first bridge surface, or Front sideThe second bridge surface, or the first (outer) longitudinal pleat leg surface of an adjacent longitudinal pleat, and / or the second (inner) longitudinal counterpleat leg surface of at least one longitudinal counterpleat is in close contact with the second (inner) longitudinal counterpleat leg surface of an adjacent leg of at least one longitudinal counterpleat, and the first (outer) longitudinal counterpleat leg surface of at least one longitudinal counterpleat is in close contact with the second (outer) longitudinal counterpleat leg surface of an adjacent leg of at least one longitudinal counterpleat, The back side second bridge surface or Front side It may be in close contact with the first bridge surface.

[0016]

[0018] In some embodiments, the first bridge has a height in the range of 10% to 25% greater than the annular gap between the inner core and the outer cage, and / or the second bridge has a height in the range of 10% to 25% greater than the annular gap between the inner core and the outer cage.

[0017]

[0019] Advantageously, filter elements, filters containing filter elements, and filter devices containing filters can have lower packing density and higher permeability while maintaining a desirable pressure difference and reduced film area, and at the same time, edge flow resistance is reduced.

[0018]

[0020] Embodiments of a filter element according to aspects of the present invention are substantially hollow cylindrical in shape and comprise a pleated porous media including a plurality of pleats of mixed heights, wherein the plurality of longitudinal pleats face inward (with their tips facing the inner core; heights (I)H1-(I)H2) and at least one longitudinal counterpleat faces outward (with its tip facing the outer cage; counterpleat: height (O)H1).

[0019]

[0021] The components of the present invention will be described in more detail below, with similar components having the same reference numeral.

[0020]

[0022] Figure 1 schematically shows one aspect of a pleated cylindrical hollow porous filter element 3000 (for ease of reference, the pleats are shown in their expanded state before being compressed to form the pleated porous filter element), which is located within an annular gap G between a perforated inner core 800 and an outer cage 900. The annular gap has a width W. The pleated cylindrical hollow porous filter element has a longitudinal axis (see Figure 3) and first and second end faces. The cylindrical hollow porous pleated filter element comprises a plurality of filter element groups GRP.

[0021]

[0023] Each of the multiple filter element groups GRP is followed by a first bridge B1, which has multiple longitudinal pleats 100A, 200A having longitudinal pleat heights. Front side First bridge surface and The back side The first filter element subgroup SG1 comprises a first bridge surface) and a second bridge B2 (which has at least one longitudinal counter pleat 100B having a longitudinal pleat height). Front side The second bridge surface and The back side It alternates with a second filter element subgroup SG2 which has a second bridge surface.

[0022]

[0024] The first bridge B1 and the second bridge B2 have heights B1H and B2H, respectively, which are greater than the width of the annular gap.

[0023]

[0025] The multiple longitudinal pleats in the first filter element subgroup SG1 include a first pleat having the largest height (I)H1 and a second longitudinal pleat having the smallest height (I)H2. The height (I)H1 of the first longitudinal pleat is within a range of 25% to 35% less than the height BH1 of the first bridge B1, and the height (I)H2 of the second longitudinal pleat is within a range of 65% to 75% less than the height BH1 of the first bridge B1.

[0024]

[0026] At least one longitudinal counter pleat in the second filter element subgroup SG2 has a longitudinal counter pleat height (O)H1 that is in the range of 25% to 35% less than the height BH2 of the second bridge B2.

[0025]

[0027] The first bridge, the longitudinal pleat, the second bridge, and at least one longitudinal pleat are in an overlapping state (as shown in Figures 2B and 3).

[0026]

[0028] According to this illustrated embodiment, the groups and subgroups in the filter element have different designs and height patterns (continuously repeating units and asymmetric orientations), namely, Group = Subgroup 1: B1, (I)H1, (I)H2, Subgroup 2: B2, (O)H1, and Group = Subgroup 1: B1, (I)H1, (I)H2, Subgroup 2: B2, (O)H1, and the filter element has any appropriate number of repeating groups.

[0027]

[0029] Each pleat comprises a pair of legs, each leg having an inner surface, an outer surface (therefore, the leg has an opposing inner surface and an opposing outer surface), a length of the leg, and a crown or tip where the legs intersect (adjacent), and the pleat is folded. Each leg has a base that abuts against a core (for longitudinal counterpleats) or cage (longitudinal pleats), and the pleats extend axially from the core or cage, respectively.

[0028]

[0030] In the embodiment shown in Figure 1, the lengths (I)H1 of each leg of the pleat are equal to each other, the lengths (I)H2 of each leg of the pleat are equal to each other, the lengths (0)H1 of each leg of the pleat are equal to each other, and the lengths (I)H2 and (O)H1 of each leg of a pair of pleats are equal to each other.

[0029]

[0031] As will be explained in more detail below, and as shown in Figures 2B and 3, for example, the formed filter element has overlapping pleats. Thus, the first bridge, the longitudinal pleat, the second bridge and at least one longitudinal counter pleat are in an overlapping state, in which the longitudinal pleat leg surface of one longitudinal pleat is in contact with the longitudinal pleat leg surface of the adjacent leg of that longitudinal pleat and the longitudinal pleat leg surface of the adjacent longitudinal pleat, The back side The first bridge surface and Front side In close contact with at least one of the second bridge surfaces, the longitudinal counterpleated leg surface of at least one longitudinal counterpleated is in contact with the longitudinal counterpleated leg surface of an adjacent leg of one longitudinal counterpleated, Front side The first bridge surface and The back side It is in close contact with at least one of the second bridge surfaces.

[0030]

[0032] Typically, each second (inner) longitudinal counterpleat leg surface of one longitudinal counterpleat is in close contact with the second (inner) longitudinal counterpleat leg surface of the adjacent leg of that longitudinal counterpleat, and the first (outer) counterpleat leg surface of one longitudinal counterpleat is also in contact with the second (inner) longitudinal counterpleat leg surface of the adjacent leg of that longitudinal counterpleat. The back side First bridge surface or Front side The second bridge surface may be in close contact with the second (inner) longitudinal pleat leg surface of one longitudinal pleat, and / or the second (inner) longitudinal pleat leg surface of one longitudinal pleat may be in close contact with the second (inner) longitudinal pleat leg surface of the adjacent leg of that longitudinal pleat, and the first (outer) pleat leg surface of one longitudinal pleat may also be in close contact with the first (outer) longitudinal pleat leg surface of the adjacent longitudinal pleat, Front side First bridge surface or The back side It may be in close contact with the second bridge surface.

[0031]

[0033] For illustrative purposes, using the embodiment shown in Figure 1 for reference, in the superimposed state, The back side The first bridge surface will be in close contact with the first (outer) longitudinal pleat leg surface of the first longitudinal pleat leg of the subsequent longitudinal pleat (100A), and the second (inner) longitudinal pleat leg surface of the first longitudinal pleat leg will be in close contact with the second (inner) longitudinal pleat leg surface of the adjacent second longitudinal pleat leg of that longitudinal pleat (100A). The first (outer) longitudinal pleat leg surface of the second longitudinal pleat leg of that longitudinal pleat (100A) will be in close contact with the first (outer) longitudinal pleat leg surface of the first longitudinal pleat leg of the subsequent (adjacent) longitudinal pleat (200A), and referring to Figure 1, for example, Front side The second bridge surface is in close contact with the first (outer) longitudinal pleat leg surface of the second longitudinal pleat leg surface of the subsequent (adjacent) longitudinal pleat (100A) and the longitudinal pleat (200A). The back side The second bridge surface will be in close contact with the first (outer) longitudinal counterpleated leg surface of the first longitudinal counterpleated leg of the subsequent (adjacent) longitudinal counterpleated (100B).

[0032]

[0034] Using Figures 1, 2B, 2C, and 3 for reference (Figure 2B shows a fully compressed filter element with overlapping pleats), an inner core 800 with cylindrical holes is arranged coaxially along the inner circumference of a pleated porous filter element 3000, a cylindrical cage 900 is arranged along the outer circumference of the filter element, an annular gap G exists between the inner core and the outer cage, and the pleated porous filter element is placed in the gap between the inner core and the outer cage, the gap having a width W.

[0033]

[0035] The first bridge B1 and the second bridge B2 each have heights B1H and B2H greater than the width of the annular gap, and therefore, each bridge B1 and B2 has bent ends that face the outer cage and inner core as part of the superimposed state. In some embodiments, the first bridge has a height in the range of 10% to 25% greater than the annular gap between the inner core and the outer cage, and / or the second bridge has a height in the range of 10% to 25% greater than the width of the annular gap between the inner core and the outer cage.

[0034]

[0036] The heights of the longitudinal pleats and longitudinal counterpleats are each smaller than the width of the annular gap between the inner core and the outer cage.

[0035]

[0037] As shown in Figure 2B, in the assembled filter element, the longitudinal pleats are folded near their leading edges (facing the inner core) as part of the overlapping pleats, and the longitudinal counter pleats are folded near their leading edges (facing the outer cage).

[0036]

[0038] The opposing surfaces of adjacent pleat legs do not need to be in close contact over the entire axial length of the filter element; however, the greater the axial length of the area of ​​close contact, the more effectively the space between the inner and outer circumferences of the filter element 3000 is utilized. Therefore, adjacent legs are in close contact over an entire continuous area that may extend over at least about 50%, in some embodiments, at least about 75%, or about 95-100% of the axial length of the filter element 3000.

[0037]

[0039] The type of porous filter media 500 (see Figure 3) that can be used in the porous filter element of the present invention is not particularly limited and can be selected according to the fluid to be filtered and the desired filtration characteristics. Preferably, the porous filter media / filter element includes a polymer media. The filter element / filter can be used to filter fluids such as liquids, gases, or mixtures thereof used in various industries. For example, the filter element / filter can be used to filter process fluids in the microelectronics industry for wet etching cleaning (e.g., a material removal process that uses liquid chemicals or etchants to remove material from wafers). For CMP (chemical mechanical planarization), the production of ultrapure water (UPW), and lithography modules, the fluids may include, for example, SC1 (standard clean 1) fluids, SC2 (standard clean 2) fluids, isopropyl alcohol (IPA, including high-temperature IPA), sulfuric acid (H2SO4, including high-temperature H2SO4), tetramethylquaternary ammonium hydroxide (TMAH, including high-temperature TAMH), hydrogen peroxide (H2O2, including high-temperature H2O2), ammonium hydroxide (NH4OH, including high-temperature NH4OH), and hydrogen fluoride (HF, including high-temperature HF), in particular, those used independently or in combination with each other.

[0038]

[0040] Typically, a pleated porous filter element includes or is a membrane. The membrane has any suitable pore structure, e.g., pore size (e.g., by bubble points, or as described in U.S. Patent No. 4,340,479, for example). LThe media may have a pore size, mean flow pore (MFP) size (as demonstrated by or by capillary condensation flow porometry), pore evaluation, pore diameter (as demonstrated by, for example, a porometer available under the trademarks of Porvair Porometer (Porvair plc, Norfolk, UK) or POROLUX (Porometer.com, Belgium)), pore evaluation, pore diameter (as demonstrated by, for example, a modified OSU F2 test as described in U.S. Patent No. 4,925,572), or removal evaluation media. The pore structure used depends on the size of the particles utilized, the composition of the fluid being treated, and the desired flow rate of the treated fluid. In some embodiments, the membrane has an mean pore size in the range of 10 nm to 150 nm (depending on the application).

[0039]

[0041] The porous membrane can have any desired critical wet surface tension (CWST, e.g., as defined in U.S. Patent No. 4,925,572). The CWST can be selected as known in the Art, for example, as further disclosed in U.S. Patents No. 5,152,905, 5,443,743, 5,472,621 and 6,074,869. Typically, the membrane has a CWST of 28 dynes / cm (28 × 10⁻¹⁶). -5 N / cm) ~ 34 dynes / cm (34 x 10 -5 It has a CWST within the range of N / cm.

[0040]

[0042] Exemplary films are disclosed in U.S. Patent Nos. 4,702,840 and 4,900,449. Other films may also be suitable, including those disclosed in U.S. Patent Nos. 4,906,374, 4,886,836, 4,964,989, 5,019,260, 4,340,479, 4,855,163, 4,744,132, 4,707,266, 4,203,848, 4,618,533, 6,039,872, 6,780,327, 6,783,937 and 7,189,322. Exemplary membranes include, but are not limited to, nylon membranes, polytetrafluoroethylene (PTFE) membranes, high-density polyethylene (HDPE) membranes, and highly asymmetric polyarylsulfone (HAPAS) membranes. Exemplary membranes may be used individually or in combination with any other exemplary membranes having the same or different properties.

[0041]

[0043] The filter may include additional elements, layers, or components that have different structures and / or functions, such as pre-filtration, support, drainage, spacing, and coherence, at least one of any one or more of these.

[0042]

[0044] For example, in the embodiment of the filter 3100 shown in Figure 3, in addition to a cylindrical inner core 800 with holes arranged coaxially along the inner circumference of the filter element and a cylindrical outer cage 900 arranged along the outer circumference of the filter element 3000, the illustrated filter includes a first pleated mesh 501 in contact with the first (e.g., upstream) surface of the porous media 500 of the filter element and a second pleated mesh 502 in contact with the second (e.g., downstream) surface of the porous media 500 of the filter element, providing a three-layer composite material. In these embodiments in which the filter includes a first pleated mesh and / or a second pleated mesh, reference to contact between pleat surfaces means contact between meshes on the referenced surface of the filter element, for example, the close contact between the second (inner) longitudinal counterpleat leg surface of one longitudinal counterpleat and the second (inner) longitudinal counterpleat leg surface of an adjacent leg of that one longitudinal counterpleat means that the mesh on the second (inner) longitudinal counterpleat leg surface of one longitudinal counterpleat and the mesh on the second (inner) longitudinal counterpleat leg surface of an adjacent leg of that one longitudinal counterpleat.

[0043]

[0045] The components that form the filter element (mesh, filter material) can be formed into a composite material using conventional filter manufacturing techniques, either before or simultaneously with corrugation.

[0044]

[0046] A mesh (the term "mesh" also includes "screen") prevents opposing surfaces of the filter material from coming into contact with each other when the pleats are overlapped, allowing the fluid to flow evenly over or from substantially all of the surface of the filter material. Thus, substantially the entire surface area of ​​the filter material can be effectively used for filtration.

[0045]

[0047] Various meshes are suitable for use in embodiments of the present invention. The mesh can be made from any material having appropriate edgewise flow characteristics, i.e., any material having appropriate resistance to fluid flow parallel to its surface. The edgewise flow resistance of the drainage mesh is preferably low enough that the pressure drop of the drainage layer is smaller than the pressure drop of the entire filter material, thereby providing a uniform distribution of fluid along the surface of the filter material.

[0046]

[0048] Typically, a filter 3100 according to one aspect of the present invention comprises end caps 850 (only one of which is shown in Figure 3) at one or both ends of a filter element 3000. The end caps 850 can be either blind (closed) or open, and the material from which they are formed and their shape can be selected according to the filtration conditions and the material of the member to which the end caps are joined. Preferably, the end caps 850 are attached to the filter element 3000, but may be attached to the inner core 800 or the outer cage 900. The end caps can be attached to the filter element using the prior art.

[0047]

[0049] If necessary, in some embodiments, inserts in the form of strips of a material having good affinity to the end cap material can be formed corrugated within the ends of the filter element 3000 to improve the sealing between both ends of the filter element 3000 and the end caps 850. For example, if the end caps are made of a fluoropolymer, strips of another fluoropolymer, such as fluorinated ethylene propylene (FEP) resin, can be formed corrugated within the ends of the filter element as inserts. The inserts only need to be wide enough to adhere the filter media to the end caps and therefore may extend only over a portion of the axial length of the filter element 3000. A typical width of the insert is about 0.5 inches.

[0048]

[0050] The filter apparatus and the filter configuration are suitable for outside-in flow, where the fluid to be filtered flows from the outer circumference (e.g., outer cage) through the filter element into the hollow center (e.g., inner core), or can be used for inside-out flow, where the fluid flows from the hollow center (e.g., inner core) through the filter element to the outer circumference (e.g., outer cage).

[0049]

[0051] The filter element 3000 shown in Figure 3 can be manufactured by various techniques, such as those described in U.S. Patent No. 5,543,047.

[0050]

[0052] In one technique, the filter composite is first corrugated to form a corrugated sheet, cut into appropriate lengths or numbers of pleats, and then formed into a cylindrical shape. The longitudinal edges of the corrugated sheet are then sealed together by conventional means to form a cylindrical filter element. The pleats of the filter element are then overlapped when the filter element 3000 is inserted into the cage 900. After the filter element is fitted into the cage 900, the core 800 is inserted into the hollow center of the filter element 10, and then the end caps are attached to the ends of the filter element to form a completed filter.

[0051]

[0053] A filter comprising a filter element is housed within a housing which comprises at least one inlet and at least one outlet, defining at least one fluid passage between the inlet and the outlet, and the filter traverses the fluid passage to constitute the filtering device. Preferably, the filtering device is sterilizable. Any housing of a suitable shape providing at least one inlet and at least one outlet may be used.

[0052]

[0054] The housing can be manufactured from any suitable rigid impermeable material, including any impermeable thermoplastic material compatible with the fluid being processed. For example, the housing can be manufactured from a metal such as stainless steel, or from a polymer. In a preferred embodiment, the housing is a polymer, and in some embodiments, it is a transparent or translucent polymer such as acrylic, polypropylene, polystyrene, or polycarbonate resin.

[0053]

[0055] The following embodiments further illustrate the present invention, but should of course not be construed as limiting its scope. [Examples]

[0054]

[0056] This embodiment demonstrates that the permeability of a test filter apparatus including a filter element according to one aspect of the present invention is improved compared to a test filter apparatus including a commercially available filter element having overlapping longitudinal pleats (such as longitudinal pleats schematically described in U.S. Patent No. 5,543,047).

[0055]

[0057] The filter element (high-density polyethylene (HDPE) membrane) is pleated using a Rabofsky PM600 corrugator (with upstream and downstream meshes) such that the first and second bridge heights are 1 inch (gap width is 0.85 inches), the height of (I)H1 is 0.6 inches, the height of (I)H2 is 0.4 inches, and the height of (O)H1 is 0.3 inches (see Figures 1, 2A, and 2B). The pore size is 15 nm.

[0056]

[0058] Commercially available filter elements (HDPE films) have a longitudinal pleat height of 1 inch.

[0057]

[0059] A filter element according to one aspect of the present invention and a commercially available filter element have the same inner core and outer cage with the same holes, and the same gap width of 85 inches. Each filter element has an open end cap at one end and a closed end cap at the other end and is placed in a test housing arranged for outside-in flow.

[0058]

[0060] A test apparatus having a filter element according to one aspect of the present invention has the same pressure drop as a test apparatus having a commercially available filter element, but with a smaller membrane area. Therefore, the transmittance (flow rate per unit area per unit pressure drop) of the filter element according to one aspect of the present invention shows an improvement of up to 20%.

[0059]

[0061] All references cited herein, including publications, patent applications, and patents, are incorporated herein by reference to the same extent as if they were included herein in their entirety, provided that each reference is individually and specifically indicated as being incorporated herein by reference.

[0060]

[0062] In the context describing the present invention (in particular in the context of the following claims), the terms “a,” “an,” “the,” and “at least one,” as well as similar reference subjects, should be interpreted as encompassing both singular and plural, unless otherwise indicated herein or unless clearly inconsistent with the context. The use of the term “at least one” followed by a list of one or more items (e.g., “at least one of A and B”) should be interpreted as meaning one item (A or B) selected from the enumerated items or any combination of two or more enumerated items (A and B), unless otherwise indicated herein or unless clearly inconsistent with the context. The terms “equip,” “have,” “include,” and “incorporate” should be interpreted as open-ended terms (i.e., “not limited to, but including”) unless otherwise indicated herein. The descriptions of value ranges herein are intended merely as a simple way to refer individually to each distinct value that falls within that range, unless otherwise indicated herein, and each distinct value is incorporated herein as if it were individually described herein. All methods described herein may be performed in any suitable order unless otherwise indicated herein or unless it is clearly inconsistent with the context. The use of any examples or exemplary language provided herein (e.g., "etc.") is intended merely to better illustrate the invention and does not imply any limitation of the scope of the invention unless otherwise claimed herein. Nothing herein should be construed as indicating that any unclaimed element is essential to the practice of the invention.

[0061]

[0063] Preferred embodiments of the present invention, including the best modes known to the inventors for carrying out the invention, are described herein. Modifications of these preferred embodiments may become apparent to those skilled in the art by reading the foregoing description. The inventors expect that those skilled in the art will appropriately use such modifications, and they intend that the invention may be carried out in ways other than those specifically described herein. Accordingly, the invention includes all modifications and equivalents of the subject matter described in the claims appended herein, as permitted by applicable law. Furthermore, unless otherwise indicated herein, or unless clearly inconsistent with the context, any combination of any possible modifications of the elements described herein is incorporated into the invention.

Claims

[Claim 1] The invention described herein.

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