Filter element with mixed pleat height

Abstract

Disclosed herein are filter elements having a mixed pleat height, filters including the filter elements, and methods of filtration using the filter elements, wherein inward-facing and outward-facing pleats have different pleat heights.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims the benefit of U.S. Provisional Patent Application 63 / 395,079, filed on August 4, 2022, which is incorporated herein by reference in its entirety. Background Art

[0003] There is a need in the art for improved pleated filter elements.

[0004] The present invention at least alleviates some of the disadvantages of the prior art. These and other advantages of the present invention will become apparent from the following description. Summary of the invention

[0005] One aspect of the present invention provides a cylindrical porous filter, which includes an inner core and an outer cage portion, with an annular gap between the inner core and the outer cage portion, a cylindrical hollow porous filter element is arranged in the annular gap between the inner core and the outer cage portion, and the annular gap has a width; wherein the cylindrical hollow porous pleated filter element has a first end surface and a second end surface, the cylindrical hollow porous pleated filter element includes a plurality of filter element groups, each of the plurality of filter element groups includes a first filter element subgroup, the first filter element subgroup includes a first bridge, the first bridge is followed by a plurality of longitudinal pleats with a longitudinal pleat height, the first filter element subgroup is alternately arranged with the second filter element subgroup, and the second filter element subgroup is alternately arranged with the second filter element subgroup. It includes a second bridge, which is followed by at least one longitudinal anti-pleat having a longitudinal anti-pleat height; wherein the heights of the first bridge and the second bridge are both greater than the width of the annular gap; wherein the plurality of longitudinal pleats in the first filter element subgroup have a first pleat with the highest height and a second longitudinal pleat with the shortest height, wherein the height of the first longitudinal pleat is within the range of 25% to 35% lower than the height of the first bridge, and the height of the second longitudinal pleat is within the range of 65% to 75% lower than the height of the first bridge; and wherein the longitudinal anti-pleat height of at least one longitudinal anti-pleat in the second filter element subgroup is within the range of 25% to 35% lower than the height of the second bridge; the first bridge, the longitudinal pleats, the second bridge and the at least one longitudinal anti-pleat are in a laid state.

[0006] In one aspect, each first bridge has a front first bridge surface and a rear first bridge surface; each of the longitudinal folds has a pair of longitudinal fold legs, each of the longitudinal fold legs has a first longitudinal fold leg surface and a second longitudinal fold leg surface; each second bridge has a front second bridge surface and a rear second bridge surface; the at least one longitudinal anti-fold has a pair of longitudinal anti-fold legs, each of the longitudinal anti-fold legs has a first longitudinal anti-fold leg surface and a second longitudinal anti-fold leg surface; the first bridge , the longitudinal folds, the second bridge and the at least one longitudinal anti-fold are in a laying state, in which the longitudinal fold leg surface of one longitudinal fold is in close contact with the longitudinal fold leg surface of the adjacent leg of the one longitudinal fold, the longitudinal fold leg surface of the adjacent longitudinal fold, at least one of the rear first bridge surface and the front second bridge surface; and the longitudinal anti-fold leg surface of the at least one longitudinal anti-fold is in close contact with at least one of the longitudinal anti-fold leg surface of the adjacent leg of the one longitudinal anti-fold, the front first bridge surface and the rear second bridge surface.

[0007] On the other hand, a method for filtering a fluid is provided, the method comprising passing the fluid through a cylindrical porous filter according to one aspect, the cylindrical porous filter comprising an inner core and an outer cage, an annular gap being provided between the inner core and the outer cage, a cylindrical hollow porous filter element being arranged in the annular gap between the inner core and the outer cage, the annular gap having a width; wherein the cylindrical hollow porous pleated filter element has a first end surface and a second end surface, the cylindrical hollow porous pleated filter element comprising a first filter element subgroup, the first filter element subgroup comprising a first bridge followed by a plurality of longitudinal pleats having a longitudinal pleat height, the first filter element subgroup being arranged alternately with the second filter element subgroup, the second filter element The subgroup includes a second bridge, which is followed by at least one longitudinal anti-pleat having a longitudinal anti-pleat height; wherein the heights of the first bridge and the second bridge are both greater than the width of the annular gap; wherein the plurality of longitudinal pleats in the first filter element subgroup have a first pleat with the highest height and a second longitudinal pleat with the shortest height, wherein the height of the first longitudinal pleat is in the range of 25% to 35% lower than the height of the first bridge, and the height of the second longitudinal pleat is in the range of 65% to 75% lower than the height of the first bridge; and wherein the longitudinal anti-pleat height of at least one longitudinal anti-pleat in the second filter element subgroup is in the range of 25% to 35% lower than the height of the second bridge; the first bridge, the longitudinal pleats, the second bridge and the at least one longitudinal anti-pleat are in a laid state.

[0008] On the other hand, a cylindrical hollow porous pleated filter element is provided, which includes a plurality of filter element groups, each of which includes a first filter element subgroup, the first filter element subgroup including a first bridge, followed by a plurality of longitudinal pleats having a longitudinal pleat height, the first filter element subgroup being alternately arranged with a second filter element subgroup, the second filter element subgroup including a second bridge, followed by at least one longitudinal anti-pleat having a longitudinal anti-pleat height; wherein the plurality of longitudinal pleats in the first filter element subgroup have a first pleat with the highest height and a second longitudinal pleat with the shortest height, wherein the height of the first longitudinal pleat is within a range of 25% to 35% lower than the height of the first bridge, and the height of the second longitudinal pleat is within a range of 65% to 75% lower than the height of the first bridge; and wherein the longitudinal anti-pleat height of at least one longitudinal anti-pleat in the second filter element subgroup is within a range of 25% to 35% lower than the height of the second bridge. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a schematic diagram schematically showing pleats with mixed pleat heights for preparing a filter element according to one aspect of the present invention (wherein, for ease of reference, the pleats are shown expanded before compression to form a pleated porous filter element, and an inner core and an outer cage are also shown), showing one aspect of a pleated cylindrical hollow porous filter element, which is arranged in an annular gap between the inner core and the outer cage, and the annular gap has a width; the pleated cylindrical hollow porous filter element includes a plurality of filter element groups, each of the plurality of filter element groups includes a first filter element subgroup, and the first filter element subgroup includes A first bridge, followed by a plurality of longitudinal pleats having a longitudinal pleat height, each first filter element subgroup being alternately arranged with a second filter element subgroup, the second filter element subgroup comprising a second bridge, followed by at least one longitudinal anti-pleat having a longitudinal anti-pleat height, wherein the first and second groups of longitudinal pleats face inward (ends facing the inner core; height (I) H1 (I) H2), and at least one longitudinal anti-pleat facing outward (ends facing the outer cage; anti-pleat; height (O) H1) has a different design and height pattern (continuous repeating units and asymmetric orientation), and the pleats are then compressed together in the prepared filter.

[0010] Figure 2A It shows Figure 1 Pictures of the filter elements shown; Figure 2B It shows Figure 1 and Figure 2A A photograph of a partial cross-sectional view of a computed tomography (CT) scan of an assembled filter element having mixed pleat heights as generally shown in FIG. Figure 2C It shows Figure 2A The filter element is shown in a partially compressed view.

[0011] Figure 3 is a cross-sectional schematic diagram of a filter according to another aspect of the present invention, the filter comprising Figure 2B Filter element shown with mixed pleat heights (filter element not fully compressed). DETAILED DESCRIPTION

[0012] According to one aspect of the present invention, a cylindrical porous filter is provided, which comprises an inner core and an outer cage portion, an annular gap is provided between the inner core and the outer cage portion, a cylindrical hollow porous filter element is arranged in the annular gap between the inner core and the outer cage portion, and the annular gap has a width; wherein the cylindrical hollow porous pleated filter element has a first end surface and a second end surface, 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, the first filter element subgroup comprises a first bridge, the first bridge is followed by a plurality of longitudinal pleats having a longitudinal pleat height, the first filter element subgroup is alternately arranged with the second filter element subgroup, and the second filter element subgroup The group includes a second bridge, which is followed by at least one longitudinal anti-pleat having a longitudinal anti-pleat height; wherein the heights of the first bridge and the second bridge are both greater than the width of the annular gap; wherein the plurality of longitudinal pleats in the first filter element subgroup have a first pleat with the highest height and a second longitudinal pleat with the shortest height, wherein the height of the first longitudinal pleat is in the range of 25% to 35% lower than the height of the first bridge, and the height of the second longitudinal pleat is in the range of 65% to 75% lower than the height of the first bridge; and wherein the longitudinal anti-pleat height of at least one longitudinal anti-pleat in the second filter element subgroup is in the range of 25% to 35% lower than the height of the second bridge; the first bridge, the longitudinal pleats, the second bridge and the at least one longitudinal anti-pleat are in a laid state.

[0013] On the other hand, a cylindrical hollow porous pleated filter element is provided, which includes a plurality of filter element groups, each of which includes a first filter element subgroup, the first filter element subgroup including a first bridge, followed by a plurality of longitudinal pleats having a longitudinal pleat height, the first filter element subgroup being alternately arranged with a second filter element subgroup, the second filter element subgroup including a second bridge, followed by at least one longitudinal anti-pleat having a longitudinal anti-pleat height; wherein the plurality of longitudinal pleats in the first filter element subgroup have a first pleat with the highest height and a second longitudinal pleat with the shortest height, wherein the height of the first longitudinal pleat is within a range of 25% to 35% lower than the height of the first bridge, and the height of the second longitudinal pleat is within a range of 65% to 75% lower than the height of the first bridge; and wherein the longitudinal anti-pleat height of at least one longitudinal anti-pleat in the second filter element subgroup is within a range of 25% to 35% lower than the height of the second bridge.

[0014] In another aspect, a method for filtering a fluid is provided, the method comprising passing the fluid through a cylindrical porous filter according to one aspect, the cylindrical porous filter comprising an inner core and an outer cage, an annular gap being provided between the inner core and the outer cage, a cylindrical hollow porous filter element being arranged in the annular gap between the inner core and the outer cage, the annular gap having a width; wherein the cylindrical hollow porous pleated filter element has a first end surface and a second end surface, the cylindrical hollow porous pleated filter element comprising a first filter element subgroup, the first filter element subgroup comprising a first bridge followed by a plurality of longitudinal pleats having a longitudinal pleat height, the first filter element subgroup being arranged alternately with a second filter element subgroup, the second filter element subgroup comprising a second bridge, The second bridge is followed by at least one longitudinal anti-pleat having a longitudinal anti-pleat height; wherein the heights of the first bridge and the second bridge are both greater than the width of the annular gap; wherein the plurality of longitudinal pleats in the first filter element subgroup have a first pleat with the highest height and a second longitudinal pleat with the shortest height, wherein the height of the first longitudinal pleat is in the range of 25% to 35% lower than the height of the first bridge, and the height of the second longitudinal pleat is in the range of 65% to 75% lower than the height of the first bridge; and wherein the longitudinal anti-pleat height of at least one longitudinal anti-pleat in the second filter element subgroup is in the range of 25% to 35% lower than the height of the second bridge; the first bridge, the longitudinal pleats, the second bridge and the at least one longitudinal anti-pleat are in a laid state; preferably, the method includes obtaining a filtered fluid.

[0015] Various aspects of the method may include outside-in flow, where the fluid to be filtered flows from the outer cage portion through the filter element into the inner core portion, or may include inside-out flow, where the fluid flows from the inner core portion through the filter element to the outer cage portion.

[0016] In a preferred aspect, a first non-permeable end cap is connected to the first end surface of the filter element.

[0017] In one aspect, each first bridge has a front first bridge surface and a rear first bridge surface; each of the longitudinal folds has a pair of longitudinal fold legs, each of the longitudinal fold legs has a first longitudinal fold leg surface and a second longitudinal fold leg surface; each second bridge has a front second bridge surface and a rear second bridge surface; the at least one longitudinal anti-fold has a pair of longitudinal anti-fold legs, each of the longitudinal anti-fold legs has a first longitudinal anti-fold leg surface and a second longitudinal anti-fold leg surface; the first bridge , the longitudinal folds, the second bridge and the at least one longitudinal anti-fold are in a laying state, in which the longitudinal fold leg surface of one longitudinal fold is in close contact with the longitudinal fold leg surface of the adjacent leg of the one longitudinal fold, the longitudinal fold leg surface of the adjacent longitudinal fold, at least one of the rear first bridge surface and the front second bridge surface; and the longitudinal anti-fold leg surface of the at least one longitudinal anti-fold is in close contact with at least one of the longitudinal anti-fold leg surface of the adjacent leg of the one longitudinal anti-fold, the front first bridge surface and the rear second bridge surface.

[0018] In some aspects, the second (inner) longitudinal pleat leg surface of a longitudinal pleat leg of one longitudinal pleat is in close contact with the second (inner) longitudinal pleat leg surface of an adjacent leg of the one longitudinal pleat, and the first (outer) longitudinal pleat leg surface of a longitudinal pleat leg of one longitudinal pleat is in close contact with the rear first bridge surface or the front second bridge surface, or the first (outer) longitudinal pleat leg surface of an adjacent longitudinal pleat and / or the second (inner) longitudinal anti-pleat leg surface of at least one longitudinal anti-pleat leg of at least one longitudinal anti-pleat is in close contact with the second (inner) longitudinal anti-pleat leg surface of an adjacent leg of the at least one longitudinal anti-pleat, and the first (outer) longitudinal anti-pleat leg surface of the longitudinal anti-pleat leg of the at least one longitudinal anti-pleat may be in close contact with the rear second bridge surface or the front first bridge surface.

[0019] In certain aspects, the first bridge has a height within a 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 within a range of 10% to 25% greater than the annular gap between the inner core and the outer cage.

[0020] Advantageously, filter elements, filters including filter elements, and filter devices including filters may have lower packing density and higher permeability while maintaining a desired pressure differential and reduced membrane area, while also reducing edge flow resistance.

[0021] According to various aspects of the present invention, embodiments of the filter element are generally in the form of a hollow cylinder, comprising a pleated porous medium with mixed pleat heights, wherein multiple longitudinal pleats face inward (ends facing the inner core; height (I)H1 (I)H2)), and at least one longitudinal reverse pleat faces outward (ends facing the outer cage; reverse pleat; height (O)H1).

[0022] Each component of the present invention will now be described in more detail below, wherein like components have like reference numerals.

[0023] Figure 1 One aspect of a pleated cylindrical hollow porous filter element 3000 is schematically shown (wherein, for ease of reference, the pleats are shown unfolded prior to being compressed to form the pleated porous filter element) disposed in an annular gap G between a perforated inner core portion 800 and an outer cage portion 900, the annular gap having a width W; the pleated cylindrical hollow porous filter element having a longitudinal axis (see FIG. Figure 3 ) and first and second end surfaces, the cylindrical hollow porous pleated filter element comprises a plurality of filter element groups GRP,

[0024] Each of the plurality of filter element groups GRP comprises a first filter element subgroup SG1, the first filter element subgroup comprising a first bridge B1 (having a front first bridge surface and a rear first bridge surface), followed by a plurality of longitudinal pleats 100A, 200A having a longitudinal pleat height, each first filter element subgroup SG1 being alternately arranged with a second filter element subgroup SG2, the second filter element subgroup comprising a second bridge B2 (having a front second bridge surface and a rear second bridge surface), followed by at least one longitudinal counter-pleat 100B having a longitudinal pleat height;

[0025] wherein the respective heights B1H and B2H of the first bridge B1 and the second bridge B2 are greater than the width of the annular gap;

[0026] wherein the plurality of longitudinal pleats in the first filter element subgroup SG1 include first pleats having a highest height (I) H1 and second longitudinal pleats having a shortest height (I) H2, wherein the height (I) H1 of the first longitudinal pleats is within a range of 25% to 35% lower than the height BH1 of the first bridge B1, and the height (I) H2 of the second longitudinal pleats is within a range of 65% to 75% lower than the height BH1 of the first bridge B1; and

[0027] wherein the longitudinal anti-pleat height (O) H1 of at least one longitudinal anti-pleat in the second filter element subgroup SG2 is in the range of 25% to 35% lower than the height BH2 of the second bridge B2;

[0028] The first bridge, the longitudinal folds, the second bridge and at least one longitudinal fold are in a laid state (eg Figure 2B and Figure 3 shown).

[0029] According to this illustrated aspect, the groups and subgroups in the filter element have different designs and height patterns (continuous repeating units and asymmetric orientations), i.e., Group = Subgroup 1: B1, (I) H1, (I) H2; Subgroup 2: B2, (O) H1; Group = Subgroup 1: B1, (I) H1, (I) H2; Subgroup 2: B2, (O) H1; wherein the filter element has any suitable number of repeating groups.

[0030] Each pleat includes a pair of legs, each leg having an inner surface and an outer surface (thus, the legs have opposing inner surfaces and opposing outer surfaces), a leg length, and a crown or end where the legs meet (adjacent) and the pleat folds. Each leg has a root that abuts the core (for longitudinal reverse pleats) or the cage (for longitudinal pleats), and the pleat extends axially from the core or cage, respectively.

[0031] exist Figure 1 In the aspect shown, the length (I)H1 of each leg of the pleats is equal to each other, the length (I)H2 of each leg of the pleats is equal to each other, the length (0)H1 of each leg of the pleats is equal to each other, and the length (I)H2 and (O)H1 of each leg in the pair of pleats are equal to each other.

[0032] As will be discussed in more detail below, e.g. Figure 2B and Figure 3 As shown, the filter element formed will have laid pleats. Thus, the first bridge, the longitudinal pleats, the second bridge and the at least one longitudinal anti-pleat are in a laid state, in which the longitudinal pleat leg surface of one longitudinal pleat is in close contact with the longitudinal pleat leg surface of the adjacent leg of the one longitudinal pleat, the longitudinal pleat leg surface of the adjacent longitudinal pleat, the rear first bridge surface and the front second bridge surface; and the longitudinal anti-pleat leg surface of the at least one longitudinal anti-pleat is in close contact with at least one of the longitudinal anti-pleat leg surface of the adjacent leg of the one longitudinal anti-pleat, the front first bridge surface and the rear second bridge surface.

[0033] Typically, each second (inner) longitudinal anti-pleat leg surface of a longitudinal anti-pleat is in close contact with the second (inner) longitudinal anti-pleat leg surface of the adjacent leg of the longitudinal anti-pleat, and the first (outer) anti-pleat leg surface of a longitudinal anti-pleat may also be in close contact with the rear first bridge surface or the front second bridge surface, and / or each second (inner) longitudinal pleat leg surface of a longitudinal pleat is in close contact with the second (inner) longitudinal pleat leg surface of the adjacent leg of the longitudinal pleat, and the first (outer) pleat leg surface of a longitudinal pleat may also be in close contact with the first (outer) longitudinal pleat leg surface, the front first bridge surface or the rear second bridge surface of the adjacent longitudinal pleat.

[0034] For example, Figure 1 The aspect shown is for reference, in the laid state, the rear first bridge surface will be in close contact with the first (outer) longitudinal fold leg surface of the first longitudinal fold leg of the subsequent longitudinal fold (100A), and the second (inner) longitudinal fold leg surface of the first longitudinal fold leg will be in close contact with the second (inner) longitudinal fold leg surface of the adjacent second longitudinal fold leg of the longitudinal fold (100A). For example, with reference to Figure 1 The first (outer) longitudinal pleat leg surface of the second longitudinal pleat leg of the 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), the front second bridge surface will be in close contact with the first (outer) longitudinal pleat leg surface of the second longitudinal pleat leg of the longitudinal pleat (200A) behind (adjacent) the longitudinal pleat (100A), and the rear second bridge surface will be in close contact with the first (outer) longitudinal anti-pleat leg surface of the first longitudinal anti-pleat leg behind (adjacent) the longitudinal anti-pleat (100B).

[0035] by Figure 1 , 2B , 2C and 3 are references ( Figure 2B What is shown is a fully compressed filter element, with pleats laid out), a cylindrical perforated inner core 800 is coaxially arranged along the inner periphery of the pleated porous filter element 3000, a cylindrical cage portion 900 is arranged along the outer periphery of the filter element, there is an annular gap G between the inner core and the outer cage portion, and the pleated porous filter element is arranged in the gap between the inner core and the outer cage portion, and the gap has a width W.

[0036] The respective heights B1H and B2H of the first bridge B1 and the second bridge B2 are greater than the width of the annular gap, so that the ends of the bridges B1 and B2 are bent toward the outer cage portion and the inner core portion, respectively, as part of the laying state. In some aspects, the height of the first bridge is within a range of 10% to 25% greater than the annular gap between the inner core portion and the outer cage portion, and / or the height of the second bridge is within a range of 10% to 25% greater than the width of the annular gap between the inner core portion and the outer cage portion.

[0037] The height of the longitudinal folds and the longitudinal counterfolds are both smaller than the width of the annular gap between the inner core portion and the outer cage portion.

[0038] like Figure 2B As shown, in the assembled filter element, the longitudinal pleats are bent near their ends (facing the inner core portion) and the longitudinal counterpleats are bent near their ends (facing the outer cage portion) as part of laying the pleats.

[0039] The opposing surfaces of adjacent pleat legs do not have to be in close contact over the entire axial length of the filter element, but the greater the length of the close contact area in the axial direction, the more effectively the space between the inner periphery and the outer periphery of the filter element 3000 can be used. Thus, adjacent legs are in close contact over a continuous area that can extend at least about 50%, in some aspects at least about 75%, or about 95-100% of the axial length of the filter element 3000.

[0040] The porous filter element of the present invention can use a porous filter medium 500 (see Figure 3 ) is not particularly limited in type and can be selected according to the fluid to be filtered and the desired filtering characteristics. Preferably, the porous filter medium / filter element comprises a polymer medium. 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 used for wet etching cleaning (e.g., a material removal process using liquid chemicals or etchants to remove materials from a wafer) in the microelectronics industry. Fluids for CMP (chemical mechanical planarization), for producing ultrapure water (UPW) and for photolithography modules may include, for example, standard clean 1 (SC1) fluid, standard clean 2 (SC2) fluid, isopropyl alcohol (IPA; including hot IPA), sulfuric acid (H2SO4, including hot H2SO4), tetramethylammonium hydroxide (TMAH; including hot TAMH), hydrogen peroxide (H2O2, including hot H2O2), ammonium hydroxide (NH4OH; including hot NH4OH) and hydrogen fluoride (HF; including hot HF), etc., which can be used alone or mixed with each other.

[0041] Typically, the pleated porous filter element comprises a membrane or is a membrane. The membrane can have any suitable pore structure, such as pore size (e.g., as demonstrated by bubble point, or by KL, as described in U.S. Pat. No. 4,340,479, or by capillary condensation flow porosimetry), average pore size; mean flow pore (MFP) size (e.g., when characterized using a porosimeter, such as Porvair Porometer (Porvair plc, Norfolk, England), or a porosimeter obtained under the trademark POROLUX (Porometer.com; Belgium)), pore grade, pore diameter (e.g., when characterized using a modified OSUF2 test, such as described in U.S. Pat. No. 4,925,572), or removal grade media. The pore structure used depends on the size of the particles used, the composition of the fluid to be treated, and the desired effluent level of the treated fluid. In certain aspects, the average pore size of the membrane is in the range of 10 nm to 150 nm (depending on the application).

[0042] The porous membrane may have any desired critical wetting surface tension (CWST, as defined, for example, in U.S. Pat. No. 4,925,572). The CWST may be selected as known in the art, for example, as further disclosed in U.S. Pat. Nos. 5,152,905, 5,443,743, 5,472,621, and 6,074,869. Typically, the CWST of the membrane is between 28 dynes / cm (28 x 10 -5 N / cm) to 34 dynes / cm(34x10 -5 N / cm).

[0043] Exemplary membranes are disclosed in U.S. Patents 4,702,840 and 4,900,449. Other membranes include U.S. Patents 4,906,374; 4,886,836; 4,964,989; 5,019,260; 4,340,479;

[0044] 4,855,163; 4,744,132; 4,707,266; 4,203,848; 4,618,533; 6,039,872;

[0045] Membranes disclosed in 6,780,327; 6,783,937 and 7,189,322 may also be suitable. Exemplary membranes include, but are not limited to, nylon membranes, polytetrafluoroethylene (PTFE) membranes, high-density polyethylene (HDPE) membranes, and high asymmetric polyarylsulfone (HAPAS) membranes. The exemplary membranes may be used alone or in combination with any other exemplary membranes having the same or different properties.

[0046] The filter may include additional elements, layers or components that may have different structures and / or functions, such as at least one of any one or more of the following: pre-filtration, support, drainage, spacing, and buffering.

[0047] For example, in Figure 3 In the aspect of the filter 3100 shown, in addition to the cylindrical perforated inner core 800 coaxially disposed along the inner periphery of the filter element and the cylindrical outer cage 900 disposed along the outer periphery of the filter element 3000, the filter shown also includes a first pleated web 501 in contact with a first (e.g., upstream) surface of the porous medium 500 of the filter element and a second pleated web 502 in contact with a second (e.g., downstream) surface of the porous medium 500 of the filter element, thereby forming a three-layer composite structure. In aspects of the filter including the first and / or second pleated webs, contact between the surfaces of the pleats refers to contact between webs on a reference surface of the filter element, for example, the second (inner) longitudinal anti-pleat leg surface of one longitudinal anti-pleat is in close contact with the second (inner) longitudinal anti-pleat leg surface of an adjacent leg of the one longitudinal anti-pleat, and refers to webs on the second (inner) longitudinal anti-pleat leg surface of one longitudinal anti-pleat being in close contact with webs on the second (inner) longitudinal anti-pleat leg surface of an adjacent leg of the one longitudinal anti-pleat.

[0048] The components forming the filter element (mesh, filter media) may be formed into a composite structure by conventional filter manufacturing techniques prior to or concurrently with corrugation.

[0049] The mesh (the term "mesh" also includes "screen") prevents the opposing surfaces of the filter medium from contacting each other and enables the fluid to flow evenly to or from all parts of the surface of the filter medium when the pleats are in the laid state. Thus, almost the entire surface area of ​​the filter medium can be effectively used for filtration.

[0050] A wide variety of screens are suitable for use in various aspects of the present invention. The screen may be made of any material that has appropriate edge flow characteristics, i.e., appropriate resistance to fluid flow through the layers in a direction parallel to its surface. The edge flow resistance of the drainage screen is preferably small enough that the pressure drop in the drainage layer is less than the pressure drop across the filter media, thereby evenly distributing the fluid along the surface of the filter media.

[0051] Typically, according to one aspect of the present invention, the filter 3100 will be provided with an end cap 850 ( Figure 3Only one of them is shown in the figure). The end cap 850 can be either a blind cap (closed type) or an open end cap, and the material and shape used can be selected according to the filtering conditions and the material of the component connected to the end cap. Preferably, the end cap 850 is attached to the filter element 3000, but it can also be attached to the inner core 800 or the outer cage 900. The end cap can be attached to the filter element using conventional techniques.

[0052] If desired, in some aspects, inserts in the form of strips of material that have a good affinity with the end cap material can be corrugated into both ends of the filter element 3000 to improve the seal between the ends of the filter element 3000 and the end cap 850. For example, when the end cap is made of a fluoropolymer, strips of another fluoropolymer (e.g., fluorinated ethylene-propylene (FEP) resin) can be corrugated into both ends of the filter element as inserts. The width of the insert only needs to be sufficient to bond the filter media to the end cap, and therefore, it can extend only a portion of the axial length of the filter element 3000. The typical width of the insert is about 0.5 inches.

[0053] Certain aspects of the filtration devices and filters are suitable for outside-to-inside flow, wherein the fluid to be filtered flows from the outer periphery (e.g., the outer cage portion) through the filter element and into the hollow center (e.g., the inner core portion), or can also be used for inside-to-outside flow, wherein the fluid flows from the hollow center (e.g., the inner core portion) through the filter element and into the outer periphery (e.g., the outer cage portion).

[0054] Figure 3 The illustrated filter element 3000 may be manufactured by a variety of techniques, such as those described in US Pat. No. 5,543,047.

[0055] In a technique, first the filter composite material is corrugated to form a corrugated sheet, cut into the pleats of the appropriate length or the appropriate number, and then formed into a cylindrical shape. Then, the longitudinal edges of the corrugated sheet are sealed to each other by a conventional method to form a cylindrical filter element. When filter element 3000 is inserted into cage portion 900, the pleats of filter element are laid. After filter element has been fitted into cage portion 900, core 800 is inserted into the hollow center of filter element 10, and then end caps are attached to the two ends of filter element to form a complete filter.

[0056] A filter comprising a filter element is disposed in a housing comprising at least one inlet and at least one outlet and defining at least one fluid flow path between the inlet and the outlet, wherein the filter traverses the fluid flow path to provide a filter device. Preferably, the filter device is sterilizable. Any housing having a suitable shape and providing at least one inlet and at least one outlet may be used.

[0057] The housing can be made of any suitable rigid impermeable material, including any impermeable thermoplastic material compatible with the fluid to be processed. For example, the housing can be made of a metal such as stainless steel or made of a polymer. In a preferred aspect, the housing is a polymer, in some aspects a transparent or translucent polymer, such as acrylic, polypropylene, polystyrene or polycarbonate resin.

[0058] The following examples further illustrate the invention but, of course, should not be construed as limiting the scope of the invention in any way.

[0059] Example

[0060] This example shows that a test filter device containing a filter element according to an aspect of the present invention has improved permeability compared to a test filter device containing a commercially available filter element having laid longitudinal pleats, as generally described in US Pat. No. 5,543,047.

[0061] The filter element was a high density polyethylene (HDPE) membrane pleated using a Rabofsky PM600 corrugator (with upstream and downstream webs) such that the first and second bridge heights were 1 inch (with the gap width being 0.85 inch), (I) H1 height was 0.6 inch, (I) H2 height was 0.4 inch, and (O) H1 height was 0.3 inch (see Figure 1 , 2A and 2B). The pore size is 15 nm.

[0062] The commercially available filter element (HDPE membrane) had a longitudinal pleat height of 1 inch.

[0063] The filter elements according to one aspect of the present invention and the commercially available filter elements had the same perforated inner core and outer cage, and the same gap width of 0.85 inches. Each filter element had an open end cap at one end and a closed end cap at the other end, and was placed in a test housing arranged for outside-in flow.

[0064] Compared to a test device using a commercially available filter element, a test device using a filter element according to one aspect of the present invention has the same pressure drop, but a smaller membrane area. Therefore, the permeability (unit area flow rate / unit pressure drop) of the filter element according to one aspect of the present invention can be increased by up to 20%.

[0065] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

[0066] In the context of describing the present invention (especially in the context of the appended claims), the use of the terms "one" and "the", "said" and "at least one" and similar references should be interpreted as covering two aspects: singular and plural, unless otherwise specified herein or clearly contradicted by the context. The list of one or more items followed by the term "at least one" (e.g., "at least one of A and B") should be understood to refer to an item selected from the listed items (A or B), or any combination of two or more listed items (A and B), unless otherwise specified herein or clearly contradicted by the context. Unless otherwise specified, the terms "include", "have", "include" and "with" should be interpreted as open terms (i.e., meaning "including but not limited to"). Unless otherwise specified herein, the enumeration of numerical ranges herein is intended only to be used as a shorthand method for referring to each individual value falling within the range, respectively, and each individual value is incorporated into the specification as if it is separately narrated herein. Unless otherwise specified herein or clearly contradicted by the context, all methods described herein can be performed in any suitable order. Unless otherwise required, the use of any and all examples or exemplary language (e.g., "such as") provided herein is intended only to better illustrate the present invention and does not limit the scope of the present invention. No language in the specification should be construed as indicating that any unclaimed element is essential to the practice of the present invention.

[0067] Preferred aspects of the present invention are described herein, including the best mode known to the inventor for carrying out the present invention. By reading the foregoing description, variations of those preferred aspects will become apparent to those of ordinary skill in the art. The inventor expects that such variations will be appropriately adopted by a skilled person, and the inventor wishes to practice the present invention in a manner different from that specifically described herein. Therefore, the present invention includes all modifications and equivalent forms of the subject matter described in the appended claims as permitted by applicable law. Moreover, unless otherwise noted herein or clearly contradictory to the context, the present invention encompasses any combination of the above-mentioned elements in all possible variations thereof.

Claims

1. A cylindrical porous filter comprising: An inner core portion and an outer cage portion, an annular gap is provided between the inner core portion and the outer cage portion, a cylindrical hollow porous pleated filter element is arranged in the annular gap between the inner core portion and the outer cage portion, and the annular gap has a width; The cylindrical hollow porous pleated filter element has a first end surface and a second end surface, and the cylindrical hollow porous pleated filter element includes a plurality of filter element groups. Each filter element group of the plurality of filter element groups includes a first filter element subset including a first bridge followed by a plurality of longitudinal pleats having a longitudinal pleat height, the first filter element subsets alternating with a second filter element subset including a second bridge followed by at least one longitudinal reverse pleat having a longitudinal reverse pleat height; wherein the heights of the first bridge and the second bridge are both greater than the width of the annular gap; wherein the plurality of longitudinal pleats in the first filter element subset have first pleats with the highest height and second longitudinal pleats with the shortest height, wherein the height of the first longitudinal pleats is within a range of 25% to 35% lower than the height of the first bridges, and the height of the second longitudinal pleats is within a range of 65% to 75% lower than the height of the first bridges; and wherein the longitudinal reverse pleat height of at least one longitudinal reverse pleat in the second subset of filter elements is within a range of 25% to 35% less than the height of the second bridge; The first bridge, the longitudinal folds, the second bridge and the longitudinal counterfolds are in the laying state.

2. The cylindrical porous filter of claim 1, wherein a first non-permeable end cap is connected to the first end surface of the filter element.

3. The cylindrical porous filter according to any one of claims 1 to 3, wherein Each first bridge has a front first bridge surface and a rear first bridge surface; each of the longitudinal pleats having a pair of longitudinal pleat legs, each of the longitudinal pleat legs having a first longitudinal pleat leg surface and a second longitudinal pleat leg surface; Each second bridge has a front second bridge surface and a rear second bridge surface; the at least one longitudinal anti-pleat having a pair of longitudinal anti-pleat legs, each of the longitudinal anti-pleat legs having a first longitudinal anti-pleat leg surface and a second longitudinal anti-pleat leg surface; The first bridge, the longitudinal folds, the second bridge and the longitudinal folds are in a laid state, in which the a longitudinal pleat leg surface of one longitudinal pleat in close contact with at least one of a longitudinal pleat leg surface of an adjacent leg of the one longitudinal pleat, a longitudinal pleat leg surface of an adjacent longitudinal pleat, a rear first bridge surface, and a front second bridge surface; and The longitudinal anti-pleat leg surface of the longitudinal anti-pleat is in intimate contact with at least one of the longitudinal anti-pleat leg surface, the front first bridge surface, and the rear second bridge surface of the adjacent leg of the one longitudinal anti-pleat.

4. The cylindrical porous filter according to any one of claims 1 to 3, wherein the height of the first bridge is in the range of 10% to 25% greater than the annular gap between the inner core portion and the outer cage portion.

5. The cylindrical porous filter according to any one of claims 1 to 4, wherein the height of the second bridge is in the range of 10% to 25% greater than the annular gap between the inner core portion and the outer cage portion.

6. A method of treating a fluid, the method comprising passing the fluid through the cylindrical porous filter according to any one of claims 1 to 5.

7. The method of claim 6, comprising passing the fluid to be filtered through the outer cage portion, the cylindrical hollow porous pleated filter element and the inner core portion.

8. A cylindrical hollow porous pleated filter element comprising: A plurality of filter element groups, each of the plurality of filter element groups comprising a first filter element subgroup, the first filter element subgroup comprising a first bridge followed by a plurality of longitudinal pleats having a longitudinal pleat height, the first filter element subgroup being alternately arranged with a second filter element subgroup, the second filter element subgroup comprising a second bridge followed by at least one longitudinal anti-pleat having a longitudinal anti-pleat height; wherein the plurality of longitudinal pleats in the first filter element subgroup have a first pleat having the highest height and a second longitudinal pleat having the shortest height, wherein the height of the first longitudinal pleat is within a range of 25% to 35% lower than the height of the first bridge, and the height of the second longitudinal pleat is within a range of 65% to 75% lower than the height of the first bridge; and wherein the longitudinal anti-pleat height of at least one longitudinal anti-pleat in the second filter element subgroup is within a range of 25% to 35% lower than the height of the second bridge.

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