TWI869941B - Cylindrical porous filter comprising filter element with mixed pleat heights and method of processing fluid with the cylindrical porous filter - Google Patents

Abstract

Filter elements having mixed pleat heights, wherein pleats facing inwardly and outwardly have different pleat heights, bridges between the groups of inwardly facing and outwardly facing pleats have different bridge heights, filters including the filter elements, and methods of filtration using the filter elements, are disclosed.

Description

A cylindrical porous filter including a filter element having mixed pleat heights and a method for treating a fluid using the cylindrical porous filter

The present invention relates to a cylindrical porous filter, which comprises an inner core and an outer cage, wherein an annular gap is provided between the inner core and the outer cage, wherein a cylindrical hollow porous pleated filter element is arranged in the annular gap between the inner core and the outer cage, 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, and the cylindrical hollow porous pleated filter element has a first end surface and a second end surface. The hollow porous pleated filter element includes a plurality of filter element groups, each of the plurality of filter element groups includes a front filter element group and a rear filter element group, the front filter element group includes a first front bridge with a first front bridge height, followed by a first longitudinal reverse pleat with a first longitudinal reverse pleat height, a first longitudinal reverse pleat with a second longitudinal reverse pleat height, and a second longitudinal reverse pleat with a second longitudinal reverse pleat height. The invention relates to a method for manufacturing a plurality of longitudinal reverse folds, wherein the third longitudinal reverse fold has a height greater than each of the first longitudinal reverse fold height and the second longitudinal reverse fold height, the second longitudinal reverse fold has a height less than each of the first longitudinal reverse fold height and the third longitudinal reverse fold height, and the first longitudinal reverse fold has a height greater than each of the first longitudinal reverse fold height and the third longitudinal reverse fold height. The height of the reverse pleat is greater than the height of the second longitudinal reverse pleat and less than the height of the third longitudinal reverse pleat; the rear filter element group includes a first rear bridge having a first rear bridge height, followed by a first longitudinal pleat having a first longitudinal pleat height, a second longitudinal pleat having a second longitudinal pleat height, a third longitudinal pleat having a third longitudinal pleat height, and a rear filter element group. , wherein the third longitudinal pleat height has a height greater than each of the first longitudinal pleat height and the second longitudinal pleat height, the second longitudinal pleat height has a height less than each of the first longitudinal pleat height and the third longitudinal pleat height, and the first longitudinal pleat height has a height greater than the second longitudinal pleat height and less than the third longitudinal pleat height; wherein the first front bridge height is greater than the first rear bridge height; the first front bridge, the first, second and third longitudinal anti-folds, the first rear bridge and the first, second and third longitudinal folds are in an overlapping state; and each of the first front bridge height, the first longitudinal anti-fold height, the second longitudinal anti-fold height and the third longitudinal anti-fold height is different from the rear front bridge height, the first The height of each of the first longitudinal pleat height, the second longitudinal pleat height and the third longitudinal pleat height; and the first front bridge height, the first longitudinal reverse pleat height, the second longitudinal reverse pleat height and the third longitudinal reverse pleat height in any filter element group, as well as the rear front bridge height, the first longitudinal pleat height, the second longitudinal pleat height and Each of the third longitudinal pleat heights is a height that is different from each of the first front bridge height, the first longitudinal reverse pleat height, the second longitudinal reverse pleat height, and the third longitudinal reverse pleat height in any other filter element group, and each of the rear front bridge height, the first longitudinal pleat height, the second longitudinal pleat height, and the third longitudinal pleat height.

Improved pleated filter elements are needed in this technology.

The present invention provides improvements over at least some of the shortcomings of the prior art. These and other advantages of the present invention will be apparent from the description set forth below.

The present invention provides a cylindrical porous filter, which includes an inner core and an outer cage, wherein an annular gap is provided between the inner core and the outer cage, wherein a cylindrical hollow porous pleated filter element is disposed in the annular gap between the inner core and the outer cage, 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, and 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 which includes a front filter element group and a rear filter element group, wherein the front filter element group includes a first front bridge with a first front bridge height, followed by a first longitudinal reverse pleat with a first longitudinal reverse pleat height, a second longitudinal reverse pleat with a second longitudinal reverse pleat height, and a first front bridge with a first front bridge height. a second longitudinal reverse fold having a height of 1/20mm, a third longitudinal reverse fold having a third longitudinal reverse fold height, wherein the third longitudinal reverse fold height has a height greater than each of the first longitudinal reverse fold height and the second longitudinal reverse fold height, and the second longitudinal reverse fold height has a height less than each of the first longitudinal reverse fold height and the third longitudinal reverse fold height, and The first longitudinal reverse pleat height has a height greater than the second longitudinal reverse pleat height and less than the third longitudinal reverse pleat height; the rear filter element group includes a first rear bridge having a first rear bridge height, followed by a first longitudinal pleat having a first longitudinal pleat height, a second longitudinal pleat having a second longitudinal pleat height, a third longitudinal pleat having a third longitudinal pleat height, and a rear filter element group. The invention relates to a plurality of longitudinal folds, wherein the third longitudinal fold height has a height greater than each of the first longitudinal fold height and the second longitudinal fold height, the second longitudinal fold height has a height less than each of the first longitudinal fold height and the third longitudinal fold height, and the first longitudinal fold height has a height greater than the second longitudinal fold height and less than the third longitudinal fold height. wherein the first front bridge height is greater than the first rear bridge height; the first front bridge, the first, second and third longitudinal anti-folds, the first rear bridge and the first, second and third longitudinal anti-folds are in an overlapping state; and each of the first front bridge height, the first longitudinal anti-fold height, the second longitudinal anti-fold height and the third longitudinal anti-fold height is different from the rear front bridge height, the first rear bridge height and the first, second and third longitudinal anti-fold height. The height of each of the first longitudinal pleat height, the second longitudinal pleat height and the third longitudinal pleat height; and the first front bridge height, the first longitudinal reverse pleat height, the second longitudinal reverse pleat height and the third longitudinal reverse pleat height in any filter element group and the rear front bridge height, the first longitudinal pleat height, the second longitudinal pleat height and each of the third longitudinal pleat heights is a height different from each of the first front bridge height, the first longitudinal reverse pleat height, the second longitudinal reverse pleat height, and the third longitudinal reverse pleat height in any other filter element group and each of the rear front bridge height, the first longitudinal pleat height, the second longitudinal pleat height, and the third longitudinal pleat height.

In one embodiment, each first front bridge has a front first front bridge surface and a rear first front bridge surface; each of the longitudinal reverse folds has a pair of adjacent longitudinal reverse fold legs, each of the longitudinal reverse fold legs has a first longitudinal reverse fold leg surface and a second longitudinal reverse fold leg surface; each first rear bridge has a front first rear bridge surface and a rear first rear bridge surface; each longitudinal fold has a pair of adjacent longitudinal fold legs, each of the longitudinal fold legs has a first longitudinal fold leg surface and a second longitudinal fold leg surface; the first front bridge, the longitudinal reverse folds, the first rear bridge, and the longitudinal reverse folds are connected to each other. The longitudinal folds are in an overlapping state, wherein the longitudinal fold leg surface of one longitudinal reverse fold is in close contact with the longitudinal fold leg surface of an adjacent leg of the longitudinal reverse fold, the longitudinal fold leg surface of an adjacent longitudinal reverse fold, the rear first front bridge surface, and the front first rear bridge surface; and the longitudinal fold leg surface of one longitudinal fold is in close contact with the longitudinal fold leg surface of an adjacent leg of the longitudinal fold, the longitudinal fold leg surface of an adjacent longitudinal fold, the front first front bridge surface, and the front first rear surface.

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 comprising a front filter element group and a rear filter element group, the front filter element group comprising a first front bridge having a first front bridge height, followed by a first longitudinal reverse pleat having a first longitudinal reverse pleat height, a second longitudinal reverse pleat having a second longitudinal reverse pleat height, and a third longitudinal reverse pleat having a third longitudinal reverse pleat height, wherein the third longitudinal reverse pleat height has a value greater than the first longitudinal reverse pleat height and The second longitudinal reverse pleat height has a height less than each of the first longitudinal reverse pleat height and the third longitudinal reverse pleat height, and the first longitudinal reverse pleat height has a height greater than the second longitudinal reverse pleat height and less than the third longitudinal reverse pleat height; the rear filter element group includes a first rear bridge having a first rear bridge height, followed by a first longitudinal pleat having the first longitudinal pleat height, a second longitudinal pleat having the second longitudinal pleat height, and a third longitudinal pleat having the third longitudinal pleat height, wherein the third longitudinal pleat height has a height greater than the first longitudinal pleat height. The invention relates to a method for manufacturing a front bridge having a first longitudinal fold height and a second longitudinal fold height, wherein the second longitudinal fold height has a height less than the first longitudinal fold height and the third longitudinal fold height, and the first longitudinal fold height has a height greater than the second longitudinal fold height and less than the third longitudinal fold height; wherein the first front bridge height is greater than the first rear bridge height; and each of the first front bridge height, the first longitudinal reverse fold height, the second longitudinal reverse fold height and the third longitudinal reverse fold height is different from each of the heights of the rear front bridge height, the first longitudinal fold height, the second longitudinal fold height and the third longitudinal fold height. height; and wherein each of the first front bridge height, the first longitudinal anti-pleat height, the second longitudinal anti-pleat height and the third longitudinal anti-pleat height in any filter element group and each of the rear front bridge height, the first longitudinal pleat height, the second longitudinal pleat height and the third longitudinal pleat height in any filter element group is different from the height of each of the first front bridge height, the first longitudinal anti-pleat height, the second longitudinal anti-pleat height and the third longitudinal anti-pleat height in any other filter element group and each of the rear front bridge height, the first longitudinal pleat height, the second longitudinal pleat height and the third longitudinal pleat height.

In another embodiment, a method for filtering a fluid is provided, the method comprising: passing the fluid through a cylindrical porous filter including an inner core and an outer cage, wherein an annular gap is provided between the inner core and the outer cage, wherein a cylindrical hollow porous pleated filter element is disposed 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 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 front filter element group and a rear filter element group, the front filter element group comprises a first front bridge having a first front bridge height, followed by a first longitudinal anti-pleat height A longitudinal reverse fold, a second longitudinal reverse fold having a second longitudinal reverse fold height, and a third longitudinal reverse fold having a third longitudinal reverse fold height, wherein the third longitudinal reverse fold height has a height greater than each of the first longitudinal reverse fold height and the second longitudinal reverse fold height, and the second longitudinal reverse fold height has a height less than the first longitudinal reverse fold height and the third longitudinal reverse fold height. The first longitudinal reverse fold height has a height greater than the second longitudinal reverse fold height and less than the third longitudinal reverse fold height; the rear filter element group includes a first rear bridge having a first rear bridge height, followed by a first longitudinal fold having the first longitudinal fold height, a second longitudinal fold having the second longitudinal fold height, a third longitudinal reverse fold height, and a rear filter element group. A third longitudinal fold having a longitudinal fold height greater than each of the first longitudinal fold height and the second longitudinal fold height, the second longitudinal fold height less than each of the first longitudinal fold height and the third longitudinal fold height, and the first longitudinal fold height greater than the second longitudinal fold height and less than the third longitudinal fold height. wherein the first front bridge height is greater than the first rear bridge height; the first front bridge, the first, second and third longitudinal anti-folds, the first rear bridge and the first, second and third longitudinal folds are in an overlapping state; and each of the first front bridge height, the first longitudinal anti-fold height, the second longitudinal anti-fold height and the third longitudinal anti-fold height is different from the rear bridge height. The height of each of the front bridge height, the first longitudinal pleat height, the second longitudinal pleat height and the third longitudinal pleat height; and the first front bridge height, the first longitudinal reverse pleat height, the second longitudinal reverse pleat height and the third longitudinal reverse pleat height in any filter element group and the rear front bridge height, the first longitudinal pleat height, the second longitudinal pleat height and the third longitudinal reverse pleat height Each of the pleat height and the third longitudinal pleat height is a height different from each of the first front bridge height, the first longitudinal reverse pleat height, the second longitudinal reverse pleat height and the third longitudinal reverse pleat height in any other filter element group and each of the rear front bridge height, the first longitudinal pleat height, the second longitudinal pleat height and the third longitudinal pleat height.

100A: First longitudinal reverse fold SG1

100B: First longitudinal fold SG2

200A: Second longitudinal reverse fold SG1

200B: Second longitudinal fold SG2

300A: Third longitudinal reverse fold SG1

300B: Third longitudinal fold SG2

400A: First longitudinal reverse fold SG3

400B: First longitudinal fold SG4

500:Porous medium

500A: Second longitudinal reverse fold SG3

500B: Second longitudinal pleat SG4

501: First pleated filter

502: Second pleated filter

600A: Third longitudinal reverse fold SG3

600B: Third longitudinal fold SG4

800: Perforated core

850: End cover

900:Outer cage

3000: Pleated cylindrical hollow porous filter element

3100:Filter

B1: First front bridge SG1

B2: First rear bridge SG2

B3: First front bridge SG3

B4: First rear bridge SG4

B5: First front bridge SG5

BH1: First front bridge height SG1

BH2: First rear bridge height SG2

BH3: First front bridge height SG3

BH4: First rear bridge height SG4

BH5: First front bridge height SG5

G: Annular gap

GRP1, GRP2, GRP3: filter element group

(I) H1: First longitudinal fold height SG2

(I) H2: Second longitudinal fold height SG2

(I) H3: The third longitudinal fold height SG2

(I) H4: First longitudinal fold height SG4

(I) H5: Second longitudinal fold height SG4

(I) H6: The third longitudinal fold height SG4

(O)H1: First longitudinal reverse fold height SG1

(O)H2: Second longitudinal reverse fold height SG1

(O)H3: The third longitudinal reverse fold height SG1

(O)H4: First longitudinal reverse fold height SG3

(O)H5: Second longitudinal reverse fold height SG3

(O)H6: The third longitudinal reverse fold height SG3

SG1, SG3, SG5: front filter element group

SG2, SG4, SG6: Post-filter component group

W: Width of the annular gap

FIG. 1 is a diagram schematically showing a filter having a filter element with mixed bridge heights and mixed pleat heights (5 bridge heights and 8 pleat heights are shown) for preparing a filter element according to an aspect of the present invention (wherein for ease of reference, the bridges and pleats are shown as being expanded before compression to form a pleated porous filter element, and the inner core and outer cage are also shown ), which shows a state of a pleated cylindrical hollow porous filter element disposed in an annular gap between an inner core and an outer cage, wherein 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 front filter element group and a rear filter element group, wherein the front filter element group includes a first filter element group having a first A first front bridge having a front bridge height, followed by a first longitudinal anti-fold having a first longitudinal anti-fold height, a second longitudinal anti-fold having a second longitudinal anti-fold height, and a third longitudinal anti-fold having a third longitudinal anti-fold height, wherein the third longitudinal anti-fold height has a height greater than each of the first longitudinal anti-fold height and the second longitudinal anti-fold height, and the second longitudinal anti-fold height is The reverse pleat height has a height less than each of the first longitudinal reverse pleat height and the third longitudinal reverse pleat height, and the first longitudinal reverse pleat height has a height greater than the second longitudinal reverse pleat height and less than the third longitudinal reverse pleat height; the rear filter element group includes a first rear bridge having a first rear bridge height, followed by a first longitudinal pleat having the first longitudinal pleat height, a rear filter element group having a first rear bridge ... The invention further comprises a second longitudinal fold having a second longitudinal fold having a second longitudinal fold height, a third longitudinal fold having a third longitudinal fold height, wherein the third longitudinal fold height has a height greater than each of the first longitudinal fold height and the second longitudinal fold height, the second longitudinal fold height has a height less than each of the first longitudinal fold height and the third longitudinal fold height, and the first longitudinal fold height has A height greater than the second longitudinal fold height and less than the third longitudinal fold height; wherein the first front bridge height is greater than the first rear bridge height; the first front bridge, the first, second and third longitudinal reverse folds, the first rear bridge and the first, second and third longitudinal folds are in an overlapping state; and the first front bridge height, the first longitudinal reverse fold height, the second longitudinal reverse fold height and the third longitudinal reverse fold height Each of the heights is different from the height of each of the rear front bridge height, the first longitudinal pleat height, the second longitudinal pleat height and the third longitudinal pleat height; and each of the first front bridge height, the first longitudinal anti-pleat height, the second longitudinal anti-pleat height and the third longitudinal anti-pleat height in any filter element group and the rear front bridge height, the first longitudinal pleat height, Each of the second longitudinal pleat height and the third longitudinal pleat height is a height different from each of the first front bridge height, the first longitudinal reverse pleat height, the second longitudinal reverse pleat height and the third longitudinal reverse pleat height in any other filter element group, and each of the rear front bridge height, the first longitudinal pleat height, the second longitudinal pleat height and the third longitudinal pleat height. As shown in this figure, according to aspects of the present invention, each of the outward-facing pleats 100A, 200A, 300A, 400A, 500A, 600A having respective heights ((O)H1 to (O)H6) and each of the inward-facing pleats 100B, 200B, 300B, 400B, 500B, 600B having respective heights ((I)H1 to (I)H6) and each of the bridges (B1 to B5) have different heights, and the heights or patterns are non-repeating (non-repeating units and asymmetric orientation).

[Figure 2] is a photograph showing a computed tomography (CT) scan of the assembled filter element having a hybrid bridge height and a hybrid pleat height as generally shown in Figure 1.

[FIG. 3] is a diagram showing a perspective cross-sectional view of a filter according to another embodiment of the present invention, the filter comprising a filter element having a mixed bridge height and a mixed pleat height as generally shown in FIG. 1 and FIG. 2 (the filter element is not fully compressed).

According to an aspect of the present invention, a cylindrical porous filter is provided, which includes an inner core and an outer cage, wherein an annular gap is provided between the inner core and the outer cage, wherein a cylindrical hollow porous pleated filter element is disposed in the annular gap between the inner core and the outer cage, and the annular gap has a width; wherein the cylindrical hollow porous pleated filter element has first and second end surfaces. The cylindrical hollow porous pleated filter element comprises a plurality of filter element groups, each of the plurality of filter element groups comprises a front filter element group and a rear filter element group, the front filter element group comprises a first front bridge having a first front bridge height, followed by a first longitudinal reverse pleat having a first longitudinal reverse pleat height, a second longitudinal reverse pleat having a second longitudinal reverse pleat height, a first front bridge having a first front bridge height, a first longitudinal reverse pleat having a first longitudinal reverse pleat height, a first longitudinal reverse pleat having a second longitudinal reverse pleat ... a second longitudinal reverse fold having a second longitudinal reverse fold having a second longitudinal reverse fold having a second longitudinal reverse fold having a third longitudinal reverse fold having a third longitudinal reverse fold height, wherein the third longitudinal reverse fold height has a height greater than each of the first longitudinal reverse fold height and the second longitudinal reverse fold height, and the second longitudinal reverse fold height has a height less than each of the first longitudinal reverse fold height and the third longitudinal reverse fold height, and The first longitudinal reverse pleat height has a height greater than the second longitudinal reverse pleat height and less than the third longitudinal reverse pleat height; the rear filter element group includes a first rear bridge having a first rear bridge height, followed by a first longitudinal pleat having a first longitudinal pleat height, a second longitudinal pleat having a second longitudinal pleat height, a third longitudinal pleat having a third longitudinal pleat height, and a rear filter element group. The invention relates to a plurality of longitudinal folds, wherein the third longitudinal fold height has a height greater than each of the first longitudinal fold height and the second longitudinal fold height, the second longitudinal fold height has a height less than each of the first longitudinal fold height and the third longitudinal fold height, and the first longitudinal fold height has a height greater than the second longitudinal fold height and less than the third longitudinal fold height. wherein the first front bridge height is greater than the first rear bridge height; the first front bridge, the first, second and third longitudinal anti-folds, the first rear bridge and the first, second and third longitudinal anti-folds are in an overlapping state; and each of the first front bridge height, the first longitudinal anti-fold height, the second longitudinal anti-fold height and the third longitudinal anti-fold height is different from the rear front bridge height, The height of each of the first longitudinal pleat height, the second longitudinal pleat height and the third longitudinal pleat height; and each of the first front bridge height, the first longitudinal reverse pleat height, the second longitudinal reverse pleat height and the third longitudinal reverse pleat height in any filter element group and the rear front bridge height, the first longitudinal pleat height, the second longitudinal pleat height and each of the third longitudinal pleat heights is a height different from each of the first front bridge height, the first longitudinal reverse pleat height, the second longitudinal reverse pleat height, and the third longitudinal reverse pleat height in any other filter element group and each of the rear front bridge height, the first longitudinal pleat height, the second longitudinal pleat height, and the third longitudinal pleat height.

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 comprising a front filter element group and a rear filter element group, the front filter element group comprising a first front bridge having a first front bridge height, followed by a first longitudinal reverse pleat having a first longitudinal reverse pleat height, a second longitudinal reverse pleat having a second longitudinal reverse pleat height, and a third longitudinal reverse pleat having a third longitudinal reverse pleat height, wherein the third longitudinal reverse pleat height has a value greater than the first longitudinal reverse pleat height and The second longitudinal reverse pleat height has a height less than each of the first longitudinal reverse pleat height and the third longitudinal reverse pleat height, and the first longitudinal reverse pleat height has a height greater than the second longitudinal reverse pleat height and less than the third longitudinal reverse pleat height; the rear filter element group includes a first rear bridge having a first rear bridge height, followed by a first longitudinal pleat having the first longitudinal pleat height, a second longitudinal pleat having the second longitudinal pleat height, and a third longitudinal pleat having the third longitudinal pleat height, wherein the third longitudinal pleat height has a height greater than the first longitudinal pleat height. The invention relates to a method for manufacturing a front bridge having a first longitudinal fold height and a second longitudinal fold height, wherein the second longitudinal fold height has a height less than the first longitudinal fold height and the third longitudinal fold height, and the first longitudinal fold height has a height greater than the second longitudinal fold height and less than the third longitudinal fold height; wherein the first front bridge height is greater than the first rear bridge height; and each of the first front bridge height, the first longitudinal reverse fold height, the second longitudinal reverse fold height and the third longitudinal reverse fold height is different from each of the heights of the rear front bridge height, the first longitudinal fold height, the second longitudinal fold height and the third longitudinal fold height. height; and wherein each of the first front bridge height, the first longitudinal anti-pleat height, the second longitudinal anti-pleat height and the third longitudinal anti-pleat height in any filter element group and each of the rear front bridge height, the first longitudinal pleat height, the second longitudinal pleat height and the third longitudinal pleat height in any filter element group is different from the height of each of the first front bridge height, the first longitudinal anti-pleat height, the second longitudinal anti-pleat height and the third longitudinal anti-pleat height in any other filter element group and each of the rear front bridge height, the first longitudinal pleat height, the second longitudinal pleat height and the third longitudinal pleat height.

In another embodiment, a method for filtering a fluid is provided, the method comprising: passing the fluid through a cylindrical porous filter including an inner core and an outer cage, wherein an annular gap is provided between the inner core and the outer cage, wherein a cylindrical hollow porous pleated filter element is disposed in the annular gap between the inner core and the outer cage, and the annular gap has a width; wherein the ... The filter element has first and second end surfaces, the cylindrical hollow porous pleated filter element includes a plurality of filter element groups, each of the plurality of filter element groups includes a front filter element group and a rear filter element group, the front filter element group includes a first front bridge having a first front bridge height, followed by a first longitudinal reverse pleat having a first longitudinal reverse pleat height. The invention relates to a method of manufacturing a plurality of longitudinal reverse folds, a second longitudinal reverse fold having a second longitudinal reverse fold height, and a third longitudinal reverse fold having a third longitudinal reverse fold height, wherein the third longitudinal reverse fold height has a height greater than each of the first longitudinal reverse fold height and the second longitudinal reverse fold height, and the second longitudinal reverse fold height has a height less than each of the first longitudinal reverse fold height and the third longitudinal reverse fold height. The first longitudinal reverse fold height has a height greater than the second longitudinal reverse fold height and less than the third longitudinal reverse fold height; the rear filter element group includes a first rear bridge having a first rear bridge height, followed by a first longitudinal fold having a first longitudinal fold height, a second longitudinal fold having a second longitudinal fold height, a third longitudinal fold having a third longitudinal fold height, longitudinal pleats, wherein the third longitudinal pleat height has a height greater than each of the first longitudinal pleat height and the second longitudinal pleat height, the second longitudinal pleat height has a height less than each of the first longitudinal pleat height and the third longitudinal pleat height, and the first longitudinal pleat height has a height greater than the second longitudinal pleat height and less than the third longitudinal pleat height; wherein the height of the first front bridge is greater than the height of the first rear bridge; the first front bridge, the first, second and third longitudinal anti-folds, the first rear bridge and the first, second and third longitudinal folds are in an overlapping state; and each of the first front bridge height, the first longitudinal anti-fold height, the second longitudinal anti-fold height and the third longitudinal anti-fold height is different from the height of the rear front bridge, the height of the first longitudinal fold height and the height of the third longitudinal anti-fold height. , the height of each of the second longitudinal pleat height and the third longitudinal pleat height; and wherein the first front bridge height, the first longitudinal reverse pleat height, the second longitudinal reverse pleat height and the third longitudinal reverse pleat height in any filter element group and the rear front bridge height, the first longitudinal pleat height, the second longitudinal pleat height and the third longitudinal pleat height The height of the filter element is different from each of the first front bridge height, the first longitudinal anti-pleat height, the second longitudinal anti-pleat height and the third longitudinal anti-pleat height in any other filter element group and each of the rear front bridge height, the first longitudinal pleat height, the second longitudinal pleat height and the third longitudinal pleat height; preferably, the method includes obtaining a filtered fluid.

The method may include an outside-in flow, wherein the fluid to be filtered flows from the outer cage through the filter element to the inner core, or an inside-out flow, wherein the fluid flows from the inner core through the filter element to the outer cage.

In a preferred embodiment, a first impermeable end cap is connected to a first end surface of the filter element.

In one embodiment, in each of the plurality of filter groups, each of the first front bridge height, the first longitudinal anti-pleat height, the second longitudinal anti-pleat height, and the third longitudinal anti-pleat height, and each of the rear front bridge height, the first longitudinal pleat height, the second longitudinal pleat height, and the third longitudinal anti-pleat height have heights that differ from each other by at least 5%.

In one embodiment, each first front bridge has a front first front bridge surface and a rear first front bridge surface; each of the longitudinal anti-pleats has a pair of adjacent longitudinal anti-pleat legs, each of the longitudinal anti-pleat legs has a first (outer) longitudinal anti-pleat leg surface and a second (inner) longitudinal anti-pleat leg surface; each first rear bridge has a front first rear bridge surface and a rear first rear bridge surface; each longitudinal pleat has a pair of adjacent longitudinal pleat legs, each of the longitudinal pleat legs has a first (outer) longitudinal pleat leg surface and a second (inner) longitudinal pleat leg surface; the first front bridge, the longitudinal anti-pleat The first rear bridge and the longitudinal folds are in an overlapping state, wherein the longitudinal reverse fold leg surface of one longitudinal reverse fold and the longitudinal fold leg surface of the adjacent leg of one longitudinal reverse fold, the longitudinal reverse fold leg surface of the adjacent longitudinal reverse fold, the rear first front bridge surface and the front first rear bridge surface At least one of them is in close contact, and the longitudinal pleat leg surface of a longitudinal pleat is in close contact with at least one of the longitudinal pleat leg surface of an adjacent leg of a longitudinal pleat, the longitudinal pleat leg surface of an adjacent longitudinal pleat, the front first front bridge surface, and the rear first rear bridge surface.

Although the bridges all have different heights from each other, they all have a bridge height that is greater than the annular gap between the inner core and the outer cage.

Advantageously, filter elements, filters comprising filter elements, and filter devices comprising filter elements can have lower packing density and higher permeability while maintaining the desired pressure differential and reducing the membrane area while reducing edge flow resistance.

Each of the components of the present invention will now be described in more detail below, with similar components having similar reference numbers.

FIG. 1 schematically illustrates (for ease of reference, the pleats are shown as unfolded prior to compression to form a pleated porous filter element) a pleated cylindrical hollow porous filter element 3000 disposed in an annular gap G between a perforated inner core 800 and an outer cage 900, the annular gap having a width W; the pleated cylindrical hollow porous filter element having a longitudinal axis (see FIG. 3 ) and first and second end surfaces, the cylindrical hollow porous pleated filter element comprising a plurality of A plurality of filter groups GRP1, GRP2, GRP3; each of the plurality of filter element groups includes a front filter element group SG1 (GRP1), SG3 (GRP2), SG5 (GRP5) and a rear filter element group SG2 (GRP1), SG4 (GRP2), (SG6 (GRP2), not shown in the figure); the front filter element groups SG1 and SG3 respectively include a first front bridge height BH1, BH3, (GRP 3) of the first front bridge B1, B3, (B5 in GRP3), followed by first longitudinal reverse folds 100A, 400A having first longitudinal reverse fold heights (O) H1, (O) H4; second longitudinal reverse folds 200A, 500A having second longitudinal reverse fold heights (O) H2, (O) H5; third longitudinal reverse folds 300A, 600A having third longitudinal reverse fold heights (O) H3, (O) H6, wherein the third The longitudinal reverse pleat height has a height greater than each of the first longitudinal reverse pleat height and the second longitudinal reverse pleat height, the second longitudinal reverse pleat height has a height less than each of the first longitudinal reverse pleat height and the third longitudinal reverse pleat height, and the first longitudinal reverse pleat height has a height greater than the second longitudinal reverse pleat height and less than the third longitudinal reverse pleat height; the rear filter element groups SG2 and SG4 respectively include a first rear bridge B2 having a first rear bridge height BH2 and BH4 , B4, followed by first longitudinal pleats 100B, 400B having first longitudinal pleat heights (I) H1, (I) H4; second longitudinal pleats 200B, 500B having second longitudinal pleat heights (I) H2, (I) H5; third longitudinal pleats 300B, 600B having third longitudinal pleat heights (I) H3, (I) H6, wherein the third longitudinal pleat height is greater than each of the first longitudinal pleat height and the second longitudinal pleat height. The second longitudinal pleat height has a height less than each of the first longitudinal pleat height and the third longitudinal pleat height, and the first longitudinal pleat height has a height greater than the second longitudinal pleat height and less than the third longitudinal pleat height; wherein the first front bridge height BH1, BH3 is greater than the first rear bridge height BH2, BH4; the first front bridge, the first, second and third longitudinal anti-pleats, the first rear bridge and the first, second and third longitudinal pleats are in an overlapping state; and the first front bridge Each of the first front bridge height, the first longitudinal anti-pleat height, the second longitudinal anti-pleat height and the third longitudinal anti-pleat height is different from the height of each of the rear front bridge height, the first longitudinal pleat height, the second longitudinal pleat height and the third longitudinal pleat height; and wherein each of the first front bridge height, the first longitudinal anti-pleat height, the second longitudinal anti-pleat height and the third longitudinal anti-pleat height in any filter element group and the rear front bridge height, the first longitudinal pleat height, the second longitudinal Each of the first front bridge height, the first longitudinal reverse pleat height, the second longitudinal reverse pleat height, and the third longitudinal reverse pleat height is different from the following heights: each of the first front bridge height, the first longitudinal reverse pleat height, the second longitudinal reverse pleat height, and the third longitudinal reverse pleat height in any other filter element group, and each of the rear front bridge height, the first longitudinal pleat height, the second longitudinal pleat height, and the third longitudinal pleat height; the first front bridge, the longitudinal reverse pleat, the first rear bridge, and the longitudinal pleats are in an overlapping state (shown in FIG. 3).

In one embodiment, in each of the plurality of filter groups, each of the first front bridge height, the first longitudinal anti-pleat height, the second longitudinal anti-pleat height, and the third longitudinal anti-pleat height, and each of the rear front bridge height, the first longitudinal pleat height, the second longitudinal pleat height, and the third longitudinal anti-pleat height have heights that differ from each other by at least 5%, and in another embodiment, differ from each other by at least 10%.

According to the illustrated aspect, according to the aspect of the present invention, each of the outward-facing pleats 100A, 200A, 300A, 400A, 500A, 600A having respective heights ((O)H1 to (O)H6) and each of the inward-facing pleats 100B, 200B, 300B, 400B, 500B, 600B having respective heights ((I)H1 to (I)H6) and each of the bridges (B1 to B5) have different heights, and the heights or patterns are non-repeating (non-repeating units and asymmetric orientation), wherein the filter element has any suitable number of filter groups.

In some embodiments, the filter element has at least 40 groups, typically at least 46 groups.

Each pleat includes a pair of legs, each leg having a first (external) surface and a second (inner) surface (thus, the legs have opposing inner and outer surfaces), a leg length, and a crown or tip where the legs meet (adjoin) and the pleat folds. Each leg has a root adjacent to the core (for longitudinal reverse pleats) or cage (longitudinal pleats), and the pleat extends axially from the core or cage, respectively.

As will be discussed in more detail below and shown, for example, in FIG. 3 , the resulting filter element will have overlapping pleats. Thus, the first front bridge, the longitudinal reverse pleats, the first rear bridge, and the longitudinal pleats are in an overlapping state, wherein the longitudinal reverse pleat leg surface of one longitudinal reverse pleat is aligned with the longitudinal reverse pleat leg surface of an adjacent leg of one longitudinal reverse pleat, the longitudinal reverse pleat leg surface of an adjacent longitudinal reverse pleat, the rear first front bridge surface, and the front first At least one of the rear bridge surfaces is in close contact; and the longitudinal pleat leg surface of a longitudinal pleat is in close contact with at least one of the longitudinal pleat leg surface of an adjacent leg of a longitudinal pleat, the longitudinal pleat leg surface of an adjacent longitudinal pleat, the front first front bridge surface, and the rear first rear bridge surface.

Typically, each second (inner) longitudinal reverse pleat leg surface of a longitudinal reverse pleat is in close contact with the second (inner) longitudinal reverse pleat leg surface of an adjacent leg of a longitudinal reverse pleat, and the first (outer) reverse pleat leg surface of a longitudinal reverse pleat may also be in close contact with the first (outer) longitudinal reverse pleat leg surface of an adjacent longitudinal reverse pleat, the rear first front bridge surface, and the front first rear 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 an adjacent leg of a 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 of an adjacent longitudinal pleat, the front first front bridge surface and the rear first rear bridge surface.

Illustratively, using the aspect shown in FIG. 1 for reference, in the overlapping state, the rear first front bridge surface will be in close contact with the first (outer) longitudinal anti-pleat leg surface of the first longitudinal anti-pleat leg of the subsequent longitudinal anti-pleat (100A), and the second (inner) longitudinal anti-pleat leg surface of the first longitudinal anti-pleat leg will be in close contact with the second (inner) longitudinal anti-pleat leg surface of the adjacent second longitudinal anti-pleat leg of the longitudinal anti-pleat (100A). The first (outer) longitudinal reverse pleat leg surface of the second longitudinal reverse pleat leg of the longitudinal reverse pleat (100A) will be in close contact with the first (outer) longitudinal reverse pleat leg surface of the first longitudinal reverse pleat leg of the subsequent (adjacent) longitudinal reverse pleat (200A), and so on. Referring to FIG. 1, for example, the front first rear bridge surface will be in close contact with the longitudinal The first (outer) longitudinal anti-pleat leg surface of the second longitudinal pleat leg of the longitudinal anti-pleat (300A) following the anti-pleat (200A) is in close contact with the surface of the first longitudinal anti-pleat leg, and the surface of the first rear bridge 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 (100B).

Using Figures 1, 2 and 3 for reference (Figure 2 shows a fully compressed filter element with overlapping pleats), a cylindrical perforated inner core 800 is coaxially disposed along the inner periphery of a pleated porous filter element 3000, and a cylindrical cage 900 is disposed along the outer periphery of the filter element, and an annular gap G exists between the inner core and the outer cage, wherein the pleated porous filter element is disposed in the gap between the inner core and the outer cage, the gap having a width W.

In the assembled filter element, as part of the overlapping pleats, the longitudinal pleats are bent near their tips (facing the inner core), and the longitudinal counter-pleats are bent near their tips (facing the outer cage).

The opposing surfaces of adjacent legs of the pleats need not 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 efficiently the space between the inner periphery and the outer periphery of the filter element 3000 is used. Thus, the adjacent legs are in close contact over a continuous area that extends at least about 50% of the axial length of the filter element 3000, and in some embodiments, at least about 75% or about 95 to 100%.

There is no particular limitation on the type of porous filter medium 500 (see FIG. 3 ) that can be used in the porous filter element of the present invention, and it can be selected based on the fluid to be filtered and the desired filtering characteristics. Preferably, the porous filter medium/filter element comprises a polymeric medium. The filter element/filter can be used to filter fluids used in various industries, such as liquids, gases, or mixtures thereof. For example, the filter element/filter can be used to filter process fluids used for wet etch cleaning (e.g., a material removal process that uses liquid chemicals or etchants to remove material from a wafer) in the microelectronics industry. Chemical-mechanical planarization (CMP) is used to generate ultra pure water (UPW) and is used in a lithography module, and the fluid may include, for example, standard clean 1 (SC1) fluid, standard clean 2 (SC2) fluid, isopropyl alcohol (IPA; including hot IPA), sulfuric acid (H ₂ SO ₄ , including hot H ₂ SO ₄ ), tetramethylammonium hydroxide (TMAH; including hot TAMH), hydrogen peroxide (H ₂ O ₂ , including hot H ₂ O ₂ ), ammonium hydroxide (NH ₄ OH; including hot NH ₄ OH) and hydrogen fluoride (HF; including hot HF) and others, and these fluids are used independently or mixed with each other.

Typically, the pleated porous filter element comprises or is a membrane. The membrane may have any suitable pore structure, such as pore size (e.g., as evidenced by bubble point or by K _L as described, for example, in U.S. Pat. No. 4,340,479, or by capillary condensation flow porometry), mean pore size; mean flow pore (MFP) size (e.g., when characterized using a porosimeter, such as Porvair Porosimeter (Porvair plc, Norfolk, UK) or a porosimeter available under the trademark POROLUX (Porometer.com; Belgium)), pore grade, pore diameter (e.g., when characterized using a modified OSU F2 test as described, for example, in U.S. Pat. No. 4,925,572), or removal grade media. The pore structure used depends on the size of the particles to be utilized, the composition of the fluid to be processed, and the desired effluent level of the processed fluid. In some aspects, the membrane has an average pore size (depending on the application) in the range of 10 nm to 150 nm.

The porous membrane can have any desired critical wetting surface tension (CWST, as defined, for example, in U.S. Pat. No. 4,925,572). The CWST can be selected as known in the art, for example, as also disclosed, for example, in U.S. Pat. Nos. 5,152,905, 5,443,743, 5,472,621, and 6,074,869. Typically, the membrane has a CWST in the range of 28 dynes/cm (28× ^10-5 N/cm) to 34 dynes/cm (34× ^10-5 N/cm).

Exemplary membranes are disclosed in U.S. Patents 4,702,840 and 4,900,449. Other membranes, including those disclosed in U.S. Patents 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, may also be suitable. Exemplary membranes include, but are not limited to, nylon membranes, polytetrafluoroethylene (PTFE) membranes, high-density polyethylene (HDPE) membranes, and highly asymmetric polyarylethersulfone (HAPAS) membranes. The exemplary membranes may be used individually or in combination with any other exemplary membranes having the same or different properties.

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-filters, supports, drains, spacers and buffers.

For example, in the embodiment of the filter 3100 shown in FIG. 3 , 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 illustrated filter also includes a first pleated filter 501 contacting a first (e.g., upstream) surface of the porous medium 500 of the filter element and a second pleated filter 502 contacting a second (e.g., downstream) surface of the porous medium 500 of the filter element, thereby providing a three-layer composite. In those aspects where the filter includes first and/or second pleated filters, the contact between pleated surfaces mentioned refers to the contact between filters on the mentioned surfaces of the filter element, for example, the second (inner) longitudinal reverse pleat leg surface of a longitudinal reverse pleat is in close contact with the second (inner) longitudinal reverse pleat leg surface of an adjacent leg of a longitudinal reverse pleat, which means that the filter on the second (inner) longitudinal reverse pleat leg surface of a longitudinal reverse pleat is in close contact with the filter on the second (inner) longitudinal reverse pleat leg surface of an adjacent leg of a longitudinal reverse pleat.

The components forming the filter element (filter screen, filter medium) can be formed as a composite by known filter manufacturing techniques before or simultaneously with corrugation.

The filter (the term "filter" also includes "screen") prevents opposing surfaces of the filter medium from coming into contact with each other and enables fluid to flow evenly to and from substantially all portions of the surface of the filter medium when the pleats are in an overlapping state. Thus, substantially the entire surface area of the filter medium can be effectively used for filtering.

A variety of filters are suitable for use in the embodiments of the present invention. The filters may be made of any material having suitable edgewise flow characteristics, i.e., suitable resistance to fluid flowing through the layer in a direction parallel to the layer surface. The edgewise flow resistance of the drainage mesh is preferably low enough so that the pressure drop in the drainage layer is less than the pressure drop across the filter medium, thereby providing uniform distribution of the fluid along the surface of the filter medium.

Typically, a filter 3100 according to the present invention will be equipped with an end cap 850 at one or both ends of the filter element 3000 (only one of which is shown in FIG. 3 ). The end cap 850 can be a blind (closed) end cap or an open end cap, and its forming material and its shape can be selected according to the filtering conditions and the material of the component to which the end cap is to be joined. 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. Known techniques can be used to attach the end cap to the filter element.

Optionally, in some embodiments, an insert in the form of a strip of material having a good affinity for the end cap material may be corrugated into the end of the filter element 3000 to improve the seal between the two ends of the filter element 3000 and the end cap 850. For example, when the end cap is made of a fluoropolymer, a strip of another fluoropolymer such as fluorinated ethylene-propylene (FEP) resin may be corrugated into the end of the filter element as an insert. The insert need only be wide enough to join the filter medium to the end cap, and therefore, it may extend only a portion of the axial length of the filter element 3000. A typical width of the insert is about 0.5 inches.

The filter device and filter are suitable for outside-in flow, where the fluid to be filtered flows from the outer periphery (e.g., outer cage) through the filter element to the hollow center (e.g., inner core), or they 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 periphery (e.g., outer cage).

The filter element 3000 shown in FIG. 3 can be manufactured by a variety of techniques, for example, as described in U.S. Patent 5,543,047.

In one technique, the filter composite is first corrugated to form a corrugated sheet, cut into an appropriate length or number of pleats, and then formed into a cylindrical shape. The longitudinal edges of the corrugated sheet are then sealed to each other in a known manner to form a cylindrical filter element. The pleats of the filter element are then covered as the filter element 3000 is inserted into the cage 900. After the filter element has been assembled 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 complete filter.

A filter including a filter element is disposed in a housing including 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 spans the fluid flow path to provide a filtering device. Preferably, the filtering device is sterilizable. Any housing having a suitable shape and providing at least one inlet and at least one outlet may be used.

The housing may be made of any suitable rigid, impermeable material, including any impermeable thermoplastic material, which is compatible with the fluid being processed. For example, the housing may be made of a metal such as stainless steel or from a polymer. In preferred embodiments, the housing is a polymer, and in some embodiments is a transparent or translucent polymer such as an acrylic, polypropylene, polystyrene, or polycarbonate resin.

The following examples further illustrate the present invention but should of course not be construed as limiting its scope in any way.

Implementation example

This example demonstrates improved permeability of a test filter device containing a filter element according to aspects of the present invention compared to a test filter device containing a commercially available filter element having overlapping longitudinal pleats (as generally described in U.S. Patent 5,543,047).

A filter was fabricated as generally shown in FIG3 (the filter element had the configuration generally shown in FIG1 and FIG2; FIG2 also shows the seal between the ends of the filter element). The filter element (PTFE membrane with a pore size of 80 nm) was pleated (with upstream and downstream filters) using a Rabofsky PM600 corrugator.

The filter has 156 filter element groups, each of which includes a first front bridge, a filter element group before the first, second and third longitudinal reverse pleats, and a filter element group after the first rear bridge and the first, second and third longitudinal pleats, wherein the bridge or pleat heights are not repeated. The height of each bridge and pleat differs from the other heights by at least 5%.

Commercially available filter elements (PTFE membranes) have a longitudinal pleat height of 1 inch.

Filter elements according to aspects of the present invention and commercially available filter elements have the same perforated inner core and outer cage, 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 configured for outside-in flow.

Compared to a test device with a commercially available filter element, a test device with a filter element according to the present invention has a 15% lower pressure drop, but a lower membrane area. Therefore, the permeability (flow rate per unit area per unit pressure drop) of the filter element according to the present invention shows an enhancement of at least 20%.

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 set forth in its entirety herein.

Unless otherwise indicated herein or clearly contradicted by context, use of the terms "a" and "an," as well as "the," and "at least one," and similar references in the context of describing the present invention (especially in the context of the claims below) should be understood to cover both the singular and the plural. 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 to mean one item (A or B) or any combination of two or more of the listed items (A and B) unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" should be interpreted as open-ended terms (i.e., meaning "including, but not limited to") unless otherwise indicated herein or clearly contradicted by context. Unless otherwise indicated herein, the recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples or exemplary language (e.g., "such as") provided herein is intended merely to better illustrate the invention and not to limit the scope of the invention unless otherwise indicated. No language in this specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

The preferred aspects of the invention are described herein, including the best modes of carrying out the invention known to the inventors. Variations of those preferred aspects may become apparent to those of ordinary skill in the art after reading the foregoing description. The inventors expect those of ordinary skill in the art to use such variations when appropriate, and the inventors intend to implement the invention in other ways than those specifically described herein. Therefore, if permitted by applicable law, the present invention includes all modifications and equivalents of the subject matter described in the claims attached hereto. In addition, unless otherwise indicated herein or otherwise clearly contradicted by the context, the present invention covers any combination of the above elements in all possible variations thereof.

100A: First longitudinal reverse fold SG1

100B: First longitudinal fold SG2

200A: Second longitudinal reverse fold SG1

200B: Second longitudinal fold SG2

300A: Third longitudinal reverse fold SG1

300B: Third longitudinal fold SG2

400A: First longitudinal reverse fold SG3

400B: First longitudinal fold SG4

500A: Second longitudinal reverse fold SG3

500B: Second longitudinal pleat SG4

600A: Third longitudinal reverse fold SG3

600B: Third longitudinal fold SG4

800: Perforated core

900:Outer cage

3000: Pleated cylindrical hollow porous filter element

B1: First front bridge SG1

B2: First rear bridge SG2

B3: First front bridge SG3

B4: First rear bridge SG4

B5: First front bridge SG5

BH1: First front bridge height SG1

BH2: First rear bridge height SG2

BH3: First front bridge height SG3

BH4: First rear bridge height SG4

BH5: First front bridge height SG5

G: Annular gap

GRP1, GRP2, GRP3: filter element group

(I) H1: First longitudinal fold height SG2

(I) H2: Second longitudinal fold height SG2

(I) H3: The third longitudinal fold height SG2

(I) H4: First longitudinal fold height SG4

(I) H5: Second longitudinal fold height SG4

(I) H6: The third longitudinal fold height SG4

(O)H1: First longitudinal reverse fold height SG1

(O)H2: Second longitudinal reverse fold height SG1

(O)H3: The third longitudinal reverse fold height SG1

(O)H4: First longitudinal reverse fold height SG3

(O)H5: Second longitudinal reverse fold height SG3

(O)H6: The third longitudinal reverse fold height SG3

SG1, SG3, SG5: front filter element group

SG2, SG4: Post-filter component group

W: Width of the annular gap

Claims (5)

A cylindrical porous filter comprises: an inner core and an outer cage, wherein an annular gap is formed between the inner core and the outer cage, wherein a cylindrical hollow porous pleated filter element is disposed in the annular gap between the inner core and the outer cage, 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, and the cylindrical hollow porous pleated filter element has a first end surface and a second end surface. The hole pleated filter element includes a plurality of filter element groups, each of the plurality of filter element groups includes a front filter element group and a rear filter element group, the front filter element group includes a first front bridge having a first front bridge height, followed by a first longitudinal reverse pleat having a first longitudinal reverse pleat height, a second longitudinal reverse pleat having a second longitudinal reverse pleat height, and a rear filter element group. wrinkles, a third longitudinal reverse wrinkle having a third longitudinal reverse wrinkle height, wherein the third longitudinal reverse wrinkle height has a height greater than each of the first longitudinal reverse wrinkle height and the second longitudinal reverse wrinkle height, the second longitudinal reverse wrinkle height has a height less than each of the first longitudinal reverse wrinkle height and the third longitudinal reverse wrinkle height, and the first longitudinal reverse wrinkle height The rear filter element group includes a first rear bridge having a first rear bridge height, followed by a first longitudinal pleat having a first longitudinal pleat height, a second longitudinal pleat having a second longitudinal pleat height, and a third longitudinal pleat having a third longitudinal pleat height, wherein the rear filter element group includes a first rear bridge having a first rear bridge height, followed by a first longitudinal pleat having a first longitudinal pleat height, a second longitudinal pleat having a second longitudinal pleat height, and a third longitudinal pleat having a third longitudinal pleat height, wherein the rear filter element group includes a first rear bridge having a first rear bridge height, a first longitudinal pleat having a first longitudinal pleat height, and a second longitudinal pleat having a second longitudinal pleat height. The third longitudinal pleat height has a height greater than each of the first longitudinal pleat height and the second longitudinal pleat height, the second longitudinal pleat height has a height less than each of the first longitudinal pleat height and the third longitudinal pleat height, and the first longitudinal pleat height has a height greater than the second longitudinal pleat height and less than the third longitudinal pleat height; wherein the The first front bridge height is greater than the first rear bridge height; the first front bridge, the first, second and third longitudinal anti-folds, the first rear bridge and the first, second and third longitudinal anti-folds are in an overlapping state; and each of the first front bridge height, the first longitudinal anti-fold height, the second longitudinal anti-fold height and the third longitudinal anti-fold height is different from the rear front bridge height, the first The height of each of the first longitudinal pleat height, the second longitudinal pleat height and the third longitudinal pleat height; and the first front bridge height, the first longitudinal reverse pleat height, the second longitudinal reverse pleat height and the third longitudinal reverse pleat height in any filter element group and the rear front bridge height, the first longitudinal pleat height, the second longitudinal pleat height and the Each of the third longitudinal pleat heights is a height different from: each of the first front bridge height, the first longitudinal reverse pleat height, the second longitudinal reverse pleat height, and the third longitudinal reverse pleat height in any other filter element group and each of the rear front bridge height, the first longitudinal pleat height, the second longitudinal pleat height, and the third longitudinal pleat height. A cylindrical porous filter as claimed in claim 1, wherein in each of the plurality of filter groups, each of the first front bridge height, the first longitudinal anti-pleat height, the second longitudinal anti-pleat height and the third longitudinal anti-pleat height and each of the rear front bridge height, the first longitudinal pleat height, the second longitudinal pleat height and the third longitudinal anti-pleat height have heights that differ from each other by at least 5%. A method for treating a fluid, the method comprising: passing the fluid through a cylindrical porous filter as claimed in claim 1 or 2. The method of claim 3 includes allowing the fluid to be filtered to pass through the outer cage, the cylindrical hollow porous pleated filter element and the inner core. A cylindrical hollow porous pleated filter element, comprising: a plurality of filter element groups, each of the plurality of filter element groups comprising a front filter element group and a rear filter element group, the front filter element group comprising a first front bridge having a first front bridge height, followed by a first longitudinal reverse pleat having a first longitudinal reverse pleat height, a second longitudinal reverse pleat having a second longitudinal reverse pleat height, and a third longitudinal reverse pleat having a third longitudinal reverse pleat height, wherein the third longitudinal reverse pleat height has a height greater than each of the first longitudinal reverse pleat height and the second longitudinal reverse pleat height, The second longitudinal reverse pleat height has a height less than each of the first longitudinal reverse pleat height and the third longitudinal reverse pleat height, and the first longitudinal reverse pleat height has a height greater than the second longitudinal reverse pleat height and less than the third longitudinal reverse pleat height; the rear filter element group includes a first rear bridge having a first rear bridge height, followed by a first longitudinal pleat having a first longitudinal pleat height, a second longitudinal pleat having a second longitudinal pleat height, and a third longitudinal pleat having a third longitudinal pleat height, wherein the third longitudinal pleat height has a height greater than the first longitudinal pleat height and the second longitudinal pleat height. The invention relates to a method for preparing a front bridge of the present invention and a method for preparing a front bridge of the present invention. The method comprises the steps of: (a) forming a front bridge of the present invention and a rear bridge of the present invention and a rear bridge of the present invention; (b) forming a front bridge of the present invention and a rear bridge of the present invention; and (c) forming a front bridge of the present invention and a rear bridge of the present invention; and (d) forming a front bridge of the present invention and a rear bridge of the present invention; wherein the first front bridge of the present invention and a rear bridge of the present invention have a height of each of the first longitudinal reverse pleat height and a height of each of the second longitudinal reverse pleat height and a height of each of the third longitudinal reverse pleat height; and the first front bridge of the present invention and a rear bridge of the present invention have a height of each of the first longitudinal reverse pleat height and a height of each of the first longitudinal reverse pleat height and a height of each of the third longitudinal reverse pleat height; and The first front bridge height, the first longitudinal anti-pleat height, the second longitudinal anti-pleat height, and the third longitudinal anti-pleat height in any filter element group, and the rear front bridge height, the first longitudinal pleat height, the second longitudinal pleat height, and the third longitudinal pleat height in any filter element group are different from the heights of the first front bridge height, the first longitudinal anti-pleat height, the second longitudinal anti-pleat height, and the third longitudinal anti-pleat height in any other filter element group, and the rear front bridge height, the first longitudinal pleat height, the second longitudinal pleat height, and the third longitudinal pleat height.