VARIABLE FILTER MEDIUM THICKNESS FOR IMPROVED FLOW AND FILTER PERFORMANCE

Abstract

Thicker and thinner sections of a filter media web are provided in a filter element. The filter element comprises a filter media ring arranged around a central support tube. The filter media includes a pleated media layer comprising inner pleat tips adjacent to the tube and outer pleat tips spaced radially outward from the tube. The layer varies in thickness between the tips, such that there is a thinner section of media at the inner pleat tips than at the outer pleat tips.

Description

FIELD OF THE INVENTION

[0001] This invention relates generally to pleated filter media web assemblies, such as may be enclosed in filter media rings that may be supported by an inner support tube. BACKGROUND OF THE INVENTION

[0002] A filter media is often pleated to increase surface area for improved filtration performance in a compact space. In many applications, the media is wrapped around a perforated central tube to create an annular shape. The central tube provides structure to the unit during use, while fluid flow creates a differential pressure across the filter media. The amount of usable filter media in this type of unit is limited to the collective pleat peak widths at the inner diameter around the central tube.

[0003] In the prior art, proposals have been made for providing beads and / or for forming embossments in different pleated filter media arrangements, as can be seen, for example, in the following patent publications: DE102015006355A1, US10632412B2, WO02055179A1, US20140202123A1 and DE4345130C1 (see also Li et al., Research on the Filtration Performance of Pleated Filters with Rectangular and Triangular Structures Through Developed Cfd Code, https: / / papers.ssrn.com / sol3 / papers.cfm?abstract id=4126929, published on June 3, 2022).

[0004] Such previous attempts may either limit or reduce filtration capacity, such as due to clogging of the media by glue beads, and / or limit the amount of media or introduce additional complexity.

[0005] The present disclosure and embodiments herein provide other and novel solutions for increasing the flow area, particularly in embodiments where the media is wound into an annular shape. These and other advantages of the invention, as well as additional inventive features, will become apparent from the description of the invention provided herein. BRIEF OVERVIEW OF THE INVENTION

[0006] The present invention reduces the filter media thickness at the pleat tips at the inner diameter, allowing a larger usable surface area of ​​the filter media across the filter, thereby improving performance.

[0007] This type of technology is not currently used in the filtration industry. Pleated annular units have been used in the industry for decades. Generally, the media layer has a uniform thickness, which is then folded over to form pleats.

[0008] Pleats are primarily created using rotating nip rolls with projecting score bars projecting from the nip rolls that create the folded-over pleat. The height of the pleat is directly associated with the spacing of the score bars around the nip roll. According to one embodiment, an increase in the base roll diameter from one score bar to the next, such that the media is compressed with a progressive pressure from nominal pressure at one score to high pressure at the next. According to another embodiment, utilizing a flat press (see, e.g., U.S. Patent No. 11,235,270, incorporated by reference in its entirety), reciprocating die plates shape the media up and down with each reciprocation as the media is advanced between the die plates. This allows for variable-base media compression with reduced tooling complexity.

[0009] One aspect of the present invention is directed to a filter element comprising a filter media ring disposed around a central support tube. The filter media includes a pleated media layer comprising inner pleat tips adjacent to the tube and outer pleat tips spaced radially outward from the tube. The layer varies in thickness between the tips such that a thinner media section is present at the inner pleat tips than at the outer pleat tips.

[0010] Another aspect of the present invention is directed to a filter media web comprising a pleated filter media layer comprising pleat tips at opposing first and second flow surfaces. The pleated layer comprises a thinner filter media portion extending from the pleat tips at the first flow surface toward the second flow surface and a thicker filter media portion extending from the pleat tips at the second flow surface toward the first flow surface, the thicker portion being thicker than the thinner portion.

[0011] In this above aspect of a filter media web, the filter media web can be used in a filter element wherein the filter media web is wound into a ring and defines a central cavity, wherein a radially inner periphery of the ring is provided by the pleat tips on the first flow surface (i.e., the inner pleat tips) and a radially outer periphery of the ring is provided by the pleat tips on the second flow surface (i.e., the outer pleat tips) spaced radially outward from the inner radial periphery.

[0012] Yet another aspect of the present invention is directed to a method of producing a filter media pack, including: creating thicker and thinner sections of a filter media web, the thicker sections being thicker than the thinner sections; folding the filter media web at the thinner sections; folding the filter media web at the thicker sections, thereby creating pleats between folds at the thinner and thicker sections; and winding the filter media pack into an annular shape with the thinner sections at an inner radial periphery and thicker sections at the outer radial periphery.

[0013] Any of the above aspects may be used in conjunction with one or more features, either alone or in combination with each of the paragraphs below.

[0014] It is a feature that pleat scores can be provided at inner pleat tips and outer pleat tips, with the thinner medium portion adjacent to the pleat scores of the inner pleat tips, as opposed to a thicker medium portion adjacent to the pleat scores of the outer pleat tips. Preferably, the thinner portion outside the pleat scores can have a minimum thickness that is 20% to 90% thinner than a maximum thickness of the thicker portion.

[0015] It is a feature that the filter media can have a gradually increasing thickness as the filter media extends radially outward from the inner pleat tips to the outer pleat tips. Optionally, the gradually increasing thickness can also vary continuously as the filter media extends radially outward.

[0016] It is a feature that the filter medium can vary gradually in thickness as the filter medium extends from inner pleat tips radially outward to the outer pleat tips.

[0017] It is a feature that there is preferably at least one radially extending constant thickness segment in the thicker portion (e.g., unchanged thickness) as the thicker portion extends radially inward from the outer pleat tips; and optionally, the thinner portion may have a radially extending constant thickness segment.

[0018] It is a feature that the thicker medium portion is provided which is thicker than the thinner portion in that the thinner portion may be 20% to 90% thinner than a maximum thickness of the thicker portion.

[0019] It is a feature that the filter media may include: a pleat depth extending between the inner pleat tips and the outer pleat tips, between 0.9 and 7.7 centimeters; a maximum thickness between 0.2 and 5.1 millimeters.

[0020] It is a feature that the central support tube can be used, which can have an outer diameter between 1 and 40 centimeters.

[0021] It is a feature that the thinner section can remain substantially constant in thickness over a span of the filter media ring, the span being parallel to the pleat tips.

[0022] It is a feature that the filter medium may be free of embossing and has opposing generally flat surfaces between the pleat tips.

[0023] It is a feature that the thinner portion can extend between 5% and 50% of the fold depth of the folded layer, and preferably between 10% and 30% of the fold depth of the folded layer. Preferably, the thinner portion is provided only within the inner half of the fold depth.

[0024] It is a feature that the thinner section creates space at an inner periphery of the ring to provide larger flow gaps between adjacent inner pleat tips, and / or more filter media with more pleats is used in the ring (compared to the same arrangement except that the thinner section is used - see e.g. a comparison of the Fig. 2 and Fig. 3).

[0025] It is a feature that the thinner section can merge into the thicker section, while the thinner section extends radially outward perpendicular to the inner pleat tips.

[0026] It is a feature that the thinner section has a minimum thickness that is 20% to 90% thinner than a maximum thickness of the thicker section. Preferably, pleat scores are provided at the pleat tips, with the thinner and thicker sections of the filter media extending from respective pleat scores.

[0027] It is a feature that the filter medium may have a gradually increasing thickness as the filter medium extends from the pleat tips on the first flow surface perpendicular to the pleat tips on the second flow surface.

[0028] It is a feature that the filter medium can vary gradually in thickness as the filter medium extends from the pleat tips on the first flow surface perpendicular to the pleat tips on the second flow surface.

[0029] It is a feature that the filter medium may have a gradually increasing conical thickness over at least one pleat depth segment as the filter medium extends from the pleat tips at the first flow surface perpendicular to the pleat tips at the second flow surface.

[0030] It is a feature that the method of manufacturing the filter pack and / or the filter element (ie, production method) may score the filter media pack at first scores between the thinner sections and at second scores between the thicker sections, wherein folding along the first and second scores is facilitated.

[0031] It is a feature that the production method can convey the filter media web along a feed path to a plate forming press or cooperating rollers; compress the filter media web with the plate forming press or cooperating rollers to reduce a thickness of the filter media web over a region between 5% and 50% of a pleat depth of the pleats, and more preferably between 10% and 30% of the pleat depth, between 20% and 90%.

[0032] It is a feature that the production process can utilize cooperating rollers with an eccentric between them, compressing the filter media web to a variable thickness. Alternatively, the process can utilize a plate forming press, which has a variable-thickness gap between opposing plates, compressing the filter media web along the pleats to a variable thickness between folds.

[0033] It is a feature that the folded layer can contain only a single layer (e.g. a single fiber deposit).

[0034] Alternatively, the pleated layer may be a composite comprising at least two layers comprising a first and a second layer laminated together, optionally wherein the first and second layers have different filtration properties.

[0035] Although the principles, embodiments, and practice of the present invention have been described in detail herein, it should not be construed as limited to the specific illustrative forms disclosed. Therefore, those skilled in the art will recognize that various modifications to the embodiments herein are possible without departing from the spirit or scope of the invention.

[0036] Further aspects, objects and advantages of the invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE CHARACTERS

[0037] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the invention. In the figures: is Fig. 1 is an exemplary cross-section of a symmetrical / cylindrical filter element incorporating a filter media ring according to an embodiment of the present invention, taken along a plane extending along / coinciding with a central axis of the filter; is Fig. 2 a cross-section of the filter medium ring and central support tube section of the filter element from Fig. 1, showing thicker and thinner sections, with the cross section perpendicular to the central axis of the filter; is Fig. 3 a view similar to Fig. 2, which shows the filter medium without thicker and thinner sections and instead with a constant thickness; is Fig. 4 is a partially schematic side / cross-sectional view of a flat press unit according to an embodiment for forming the filter medium web with thicker and thinner sections used in the filter element of Fig. 1 and Fig. 2 can be used; is Fig. 5 is a partially schematic side / cross-sectional view of a roll forming unit according to a Fig. 4 alternative embodiment, also for forming the filter medium web with thicker and thinner sections, which in the filter element of Fig. 1 and Fig. 2 can be used; and is Fig. 6 is an isometric view of a formed web with thicker and thinner sections used in the filter element of Fig. 1 and Fig. 2 can be used. Fig. Figure 7 is an isometric view of a formed web with thicker and thinner sections used in the filter element of Fig. 1 and Fig. 2 can be used, similar to the one in Fig. 6, but wherein steps have a demarcation between thicker and thinner sections and radially extending segments of constant thickness are connected by a conical segment of the thinner section. Fig. Figure 8 is a cross-section of the filter media and central support tube section of the filter element as shown in Fig. 2, showing thicker and thinner sections, but according to an alternative embodiment in which a filter medium layer is a composite medium comprising multiple layers.

[0038] While the invention will be described in connection with certain preferred embodiments, there is no intention to limit it to those embodiments. Rather, the intention is to cover all alternatives, modifications, and equivalents included within the spirit and scope of the invention as defined by the appended claims. DETAILED DESCRIPTION OF THE INVENTION

[0039] As in the Fig. 1-2 and 6, according to one embodiment of the present invention, thicker and thinner sections 10, 12 of a filter media web 14 are provided in a filter element 16.

[0040] The filter media web 14 includes a pleated filter media layer 18 providing a plurality of pleats 20, each extending between first / inner pleat tips 22 and second / outer pleat tips 24. When assembled into a filter media pack, the first / inner pleat tips 22 are arranged adjacent to form a first / inner flow surface 26, and the second / outer pleat tips 24 are arranged to form a second / outer flow surface 28.

[0041] The arrangement could be used in a panel-like element, but they are most advantageous when arranged in a ring 30, as in the Fig. 1 and Fig. 2, where the pleated filter media layer 18 is wrapped around a central cavity 32, joining opposite cut ends of the filter media web 14. Such filter media ring assemblies in which this may be employed are shown, for example, in any of the following US patents or patent publications: US4872976A, US5078877A, US5484466A, US20030015465A1, US20070084170A1, US20070163945A1, and US7740679B2 (all of these patents / patent publications are incorporated by reference in their entirety as examples for which the filter media web 14 of the present application may be used to provide a filter media ring). The features pertaining to this apply to different types of fluids, for example, both air filters and liquid filters.

[0042] As in the Fig. 2 and Fig. 6, Fig. 7 (e.g. compared to Fig. 3), the pleated filter media layer 18 varies in thickness as the media extends perpendicularly between the inner and outer pleat tips 22, 24, such that the thinner filter media portion 12 extends from the pleat tips 22 at the first / inner flow surface 26 to the second / outer flow surface 28; and the thicker filter media portion 10 extends from the second / outer pleat tips 24 at the second / outer flow surface 28 to the first / inner flow surface 26.

[0043] As can be seen from the illustration, the thicker portion 10 of each pleat 30 is thicker than the thinner portion 12 of each pleat 30. As the thinner portion 12 extends radially outward and perpendicular to the inner pleat tips 22, the filter medium of the pleated layer ceases to be thinner at some point and becomes thicker at the thicker portion 10; and in this way, the thinner portion 12 merges into the thicker portion as the filter medium extends radially outward, as in Fig. 2 and the Fig. 6 and Fig. 7 shown.

[0044] The thickness of the filter medium web 14 can also vary continuously, as in Fig. 6, however, it is also conceivable that the change occurs only over a portion of the filter medium web 14, particularly in a region adjacent to the first / inner pleat tips 22 at the first / inner flow surface 26, as in Fig. 7 shown.

[0045] As in the comparison between Fig. 2 and Fig. 3, due to the reduced thickness, larger flow gaps 34 can be created for an improved flow area. This allows, when used in a filter medium arrangement according to Fig. 1, reducing pressure drop and providing longer filter life.

[0046] Alternatively and / or additionally, the thinner section 12 may provide the ability to pack more filter media into an annular shape, so that the number of inner pleat peaks 22 (e.g., surrounding a filter support tube 26) may be increased because there is more room for additional inner pleat peaks due to the thinner media section 12 creating more space at the inner perimeter. This allows more pleats and thus more filter media to be packed, resulting in increased filtration capacity because there is a larger available surface area through which the fluid can pass and on which filtered-out particles can be deposited. Therefore, creating enlarged flow gaps 34 may not be implemented in some embodiments.

[0047] With respect to increased flow gaps and / or increased media / pleat packing, this is particularly advantageous when used in conjunction with a central support tube 36 that can predetermine the inner diameter of the pleated filter media ring 30, wherein the filter media ring 30 is configured around a central support tube 36. When there is radially inward flow (e.g., of a fluid such as fuel, oil, other liquids, air, or other gases), the central support tube 26 can support the filter media ring 30 and prevent its inward collapse, with the first / inner flow surface 26 (e.g., the inner pleat tips 22) contacting the support tube 36 when support is needed due to fluid flow and a pressure differential.

[0048] The central support tube 26 is porous, for example perforated with a plurality of flow holes 38 to allow the fluid to flow radially inward into the central cavity 32 and along the central axis of the filter element 16.

[0049] The filter element 16 may further include opposing end caps, such as an open end cap 40 and a closed end cap 42, which may be integrally connected to opposite ends of the filter media ring 30 and may be integrally connected to the central support tube 26 at opposite ends (for example, by means of adhesive 44 located in annular recesses of the end caps).

[0050] In many of the typical air or liquid filtration applications, the central support tube 26 may have an outer diameter between 1 and 40 centimeters (and the inner diameter of the filter media ring 30 may be identical).

[0051] The open end cap 40 allows the escape of filtered fluid and the closed end cap 42 can ensure that the flow is directed in the axial direction towards the opening in the open end cap 40, which can be surrounded by an annular seal 46 that can be carried by or formed integrally with the open end cap 40 to facilitate sealing to an external mounting head, an external pipe and / or an external housing.

[0052] Returning to the nature of the pleated filter media web 14 with varying thickness, it is shown that the pleat layer has a thinner section 12 and a thicker section 10.

[0053] The thinner portion 12 has a thickness that is thinner relative to the average thickness over a radially extending span in a first region 48 immediately adjacent to the first / inner pleat tips 22, and the thicker portion 10 has a thickness that is the same or thicker relative to the average thickness over a radially extending span in a second region 50.

[0054] The wrinkle layer can, as in Fig. 6, may vary continuously in thickness between fold tips or may, as shown in Fig. 7, may also vary in a non-continuous manner (where, for example, it is also shown that the thicker medium section near the outer pleat tips may comprise a section of constant, unchanged thickness and, optionally, a radially inwardly located thinner section of constant compressed thickness). The thinner first region 48 ceases well before the second outer pleat tips 24. A reduced thickness of the thinner section 12 (e.g., a span of the region 48 having a reduced thickness relative to the middle thickness) may extend over at least 5% of the pleat depth 60, as shown in FIGS. Fig. 6 and Fig. 7. The reduced thickness region 48 of the thinner section 12 may extend up to 50% (or potentially more) of the fold depth 60, as shown in Fig. 6. However, the benefit of reducing the crowded situation at the inner pleat tips results from the reduced thickness of the filter media web directly adjacent to the inner pleat tip region. Therefore, it is more typical for the reduced thickness region 48 of the thinner section 12 to extend over between 10% and 30% of the pleat depth 60, such as in Fig. 7 shown.

[0055] Optionally, the pleat layer in the thicker portion 10 varies in the second region 50 of the second outer pleat tips 24, as shown in Fig. 6. Alternatively, as shown in Fig. 7, it may be useful not to compress the medium in the thicker second region 50, so that the thicker section 10 and the thicker second region 50 may remain either completely or predominantly uncompressed and may establish or correspond to the average thickness.

[0056] The span of the reduced thickness region 48 is determined as the span from the inner pleat tip below the mean thickness for the reduced thickness region 48, as in both alternatives of the Fig. 6 and Fig. 7. The range of the increased thickness region 50 is determined as the range from the outer fold tip at or above the mean thickness, as in both alternatives of the Fig. 6 and Fig. 7 shown.

[0057] Preferably, fold scores 52 are formed (e.g. by a scoring bar on rollers / flat molds, as in the Fig. 4 and Fig. 5) to provide predetermined folding locations for the inner and outer pleat tips 22, 24, which in the embodiment in Fig. 6 are shown (and not in Fig. 2, and / or scores may alternatively be omitted to facilitate folding in embodiments. The scores facilitate folding into creases by weakening and / or creating weakened areas, such as localized notches, in the filter media web 14.

[0058] When pleat scores are provided at the pleat tips 22, 24, the thicker and thinner portions 10, 12 at the respective pleat tips 22, 24 extend outwardly from and are adjacent to the pleat scores 52.

[0059] Therefore, and as used herein, the thicker and thinner sections 10, 12 are determined independently of the characteristics of the scores 52 used for folding. In other words, the pleat scores 52 are not taken into account when identifying and considering relative thicknesses at regions of the inner and outer pleat tips 22, 24 (and are similarly not taken into account when identifying and considering relative thicknesses of thicker and thinner sections 10, 12). Pleat scores 52 may be formed in the thicker or thinner sections 10, 12, but pleat scores 52 are thus not taken into account when comparing, measuring, and / or determining thicker or thinner sections 10, 12.

[0060] For example, as shown, the pleat score 52 for the outer pleat tips 24 creates a very localized region / line for folding that may be thinner than the thinner section 12. However, the thin pleat score 52 for the outer pleat tips 24 is disregarded when comparing to a thinner section 12 of the filter media web 14 located at the inner pleat tips 12 (compared to the thicker section 10 such as at the outer pleat tips 24) and is not considered as part of the thicker section 10. Similarly, the thin pleat score 52 for the inner pleat tips 22 is disregarded when comparing the thinner section 12 to the thicker section 10 and is not considered as part of the thinner section 12.

[0061] This being said, and as in the Fig. 6 and Fig. 7 (with carvings) and Fig. 2 (without scribes), the thicker portion 10 has a maximum thickness 56, which may preferably be an unchanged medium thickness (or alternatively, a slightly reduced thickness from unchanged), typically approximately between 0.2 millimeters and 5.1 millimeters prior to the thickness reduction to create the thinner portion 12; and the thickness reduction for the minimum thickness 58 may be between 20% and 90% of this maximum thickness 56 upon creation of the thinner portion 12. Preferably, the thinner portion has a minimum thickness 58 that is at least 50% less than the maximum thickness 56.

[0062] As already mentioned above, the reduction in thickness is greater towards the inner pleat tips 22, and the filter medium has a reduced thickness over at least 5% of the pleat depth 60 and up to 50% of the pleat depth (more typically between 10% and 30% in order to maximally benefit from the advantages regarding the crowded situation of the inner pleat tips) as the filter medium in the illustrated first region 48 extends from the first inner flow surface 26 to the second outer flow surface 28. For example, the filter medium, as shown in Fig. 6, has a gradually increasing thickness as the filter medium extends from the inner pleat tips 22 to the outer pleat tips 24; and for example, the filter medium as shown in Fig. 7, regions with gradually varying thickness.

[0063] In many of the typical pleated ring examples, such as those patents / publications referenced in the above-mentioned patents, the filter pack (e.g., pleated filter media ring 30) has a pleat depth 60 extending between the pleat tips at the first and second flow surfaces of between 0.9 and 7.7 centimeters.

[0064] In many of the typical pleated ring examples, such as those patents / publications referenced in the above-mentioned patents, the maximum thickness (i.e., the same thickness as the maximum thickness 26) of the filter media web 14 is most typically between 0.2 and 5.1 millimeters.

[0065] While a variation in the direction of the pleat depth is useful, there is no reason for a variation in the direction perpendicular to it (e.g., the span between the end caps 40, 42). Fig. 6 that the thinner portion 12 may remain substantially constant (e.g., constant or varying by less than 10%) in thickness T at various locations of the first region 48 over a span 62 of the filter media web 14 between opposite sides (i.e., over the span 62 parallel to the pleat tips).

[0066] Furthermore, the filter medium may be free of embossing and have opposing generally flat surfaces 64 between the pleat tips 22, 24, as in Fig. 6 and Fig. 2. By "generally flat" is meant free of separate embossments having a depth greater than the thickness of the media web. However, the term "generally flat" optionally permits the use of "grooving / corrugating" rolls, which may sometimes be used to create shallow, continuous corrugations / grooves in the filter media web, typically perpendicular to the pleat tips, with such corrugations / grooves having a groove depth typically less than the maximum thickness (e.g., unaltered thickness) of the filter media web.

[0067] To maximize the size of the useful flow gap 34, the thinner section 12 is thinnest near an apex (e.g., such as the location of the pleat score 52) of the inner pleat tips 22 and increases in thickness across the first region 48 over at least a portion of the pleats 20 toward the outer pleat tips 24.

[0068] As in one of Fig. 4 and Fig. 5 (with additional reference to the Fig. 1 and Fig. 2) a method for producing a filter media package includes: producing thicker and thinner sections 10, 12 of the filter media web 14 by one of the Fig. 4 and Fig. 5; folding the filter media web 14 at the thinner sections 12 and folding the filter media web 14 at the thicker sections 10, thereby creating pleats 20 between folds at the thinner and thicker sections; and winding the filter media package into an annular shape (e.g., the filter media ring 30) with the thinner sections 12 at an inner radial periphery and with thicker sections 10 at the outer radial periphery, as shown in the Fig. 1 and Fig. 2 can be seen.

[0069] To facilitate folding, the method preferably utilizes scoring the filter media pack at scores 52 including first scores between the thinner sections 12 and second scores between the thicker sections 10, facilitating folding along the first and second scores.

[0070] In the Fig. 4 or Fig. 5, the method includes conveying the filter media web 14 along a feed path to either a platen press 66 (e.g., upper and lower press plates 68, 70) or to a pair of cooperating rollers 72, 74. Either of these pieces of equipment may enable compression of the filter media web 14 with the platen press 66 or the cooperating rollers 72, 74 to reduce a thickness of the filter media web between 20% and 90% over a region between at least 5% and up to 50% of the pleat depth 60.

[0071] As in Fig. 5, the process utilizes cooperating rollers 72, 74 having an eccentric 76 therebetween that compresses the filter media web to a variable thickness, and may also include scoring bars 78 to facilitate the formation of scores 52.

[0072] As in Fig. 4 when the plate forming press 66 is used, wherein the plate forming press has a variable thickness gap 80 between opposing plates 68, 70 that compresses the filter media web along the pleats to a variable thickness between folds. One or both plates may also have scoring bars 82 to enable the formation of scores 52. The embodiment of Fig. 4 can be used in the equipment and methods shown in US Patent No. 11,235,270.

[0073] As in Fig. 2, the filter media web 14 and the pleated filter media layer 18 thereof may include only a single filter media layer, which may be a homogeneous deposit of filter media fibers (e.g., cellulose fibers, polymer / synthetic fibers, glass fibers, additives (binders, adsorbents, etc.) or mixtures thereof).

[0074] Alternatively, as in Fig. 8, the filter media web 14a and the pleated filter media layer 18a thereof may be a composite and include at least two layers comprising a first and a second layer laminated together (such as the illustrated layers 81, 82, 83 laminated together). Layers 81 and 83 are schematically shown as like layers of filter media fibers or scrim fabric and may have the same filtration properties (or alternatively, if desired, different filtration properties), while layer 82 includes filter media fibers with a different filtration property than layers 81, 83. Each layer may be a deposit of filter media fibers (e.g., cellulosic fibers, polymer / synthetic fibers, glass fibers), additives (binders, adsorbents, etc.), or screen / scrim fabrics.

[0075] As should be apparent, the embodiment and the filter medium web 14a can be Fig. 8 in the embodiments of the Fig. 1-7 for the single layer web 14, so that the previous description of the Fig. 1-7 also applies here and vice versa. For example, pleat tips with thicker and thinner sections are also produced similarly to the previous embodiments, as in the embodiment in Fig. 8 shown.

[0076] 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 as if each were set forth in its entirety herein.

[0077] The use of the terms "a" and "an" and similar referents in the context of describing the invention (particularly in the context of the claims below) is to be construed to cover both the singular and the plural, unless otherwise stated herein or clearly contradicted by the context. The terms "including," "having," "comprising," and "containing" are to be construed as open-ended, non-restrictive terms (i.e., having the meaning of "including, but not limited to"), unless otherwise noted. The repetition of ranges of values ​​herein is merely intended as a convenient way to individually refer to each separate value falling within the range, unless otherwise stated herein, and each separate value is incorporated into the specification as if individually recited herein.All methods described herein may be performed in any suitable order, unless otherwise indicated herein or clearly contradicted by context. The use of any examples or exemplary language (e.g., "such as") provided herein is merely intended to facilitate understanding of the invention and is not intended to limit the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating that any unclaimed element is essential to the practice of the invention.

[0078] Preferred embodiments of this invention are described herein, comprising the best mode known to the inventors for carrying out the invention. Variations of these preferred embodiments may be apparent to those of ordinary skill in the art after reviewing the foregoing description. The inventors expect that those skilled in the art will employ such variations accordingly, and the inventors contemplate that the invention may be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto, to the extent permitted by applicable law. Furthermore, any combination of the above-described elements in all possible variations thereof is included in this invention unless otherwise stated herein or clearly contradicted by context. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 102015006355A1

[0003] US 10632412B2

[0003] WO 02055179A1

[0003] US 20140202123A1

[0003] DE 4345130C1

[0003] US 11,235,270 [0008, 0072] US 4872976A

[0041] US 5078877A

[0041] US 5484466A

[0041] US 20030015465A1

[0041] US 20070084170A1

[0041] US 20070163945A1

[0041] US 7740679B2

[0041] Cited non-patent literature

[0000] https: / / papers.ssrn.com / sol3 / papers.cfm?abstract id=4126929

[0003]

Claims

[1] A filter element comprising a ring of filter media disposed around a central support tube, the filter media including a pleated media layer having inner pleat tips adjacent the tube and outer pleat tips spaced radially outwardly from the tube, the pleated layer varying in thickness between the tips such that there is a thinner portion of media at the inner pleat tips than at the outer pleat tips. [2] The filter element of claim 1, wherein pleat scores are located at the inner pleat tips and at the outer pleat tips, wherein the thinner media portion is adjacent to the pleat scores of the inner pleat tips compared to a thicker media portion adjacent to pleat scores of the outer pleat tips. [3] The filter element of claim 2, wherein the thinner portion outside the pleat scores has a minimum thickness that is 20% to 90% thinner than a maximum thickness of the thicker portion. [4] The filter element of claim 1, wherein the filter media has a gradually increasing thickness as the filter media extends radially outward from the inner pleat tips to the outer pleat tips. [5] The filter element of claim 1, wherein the filter media varies stepwise in thickness as the filter media extends radially outward from inner pleat tips to outer pleat tips. [6] The filter element of claim 1, wherein the thicker media portion near the outer pleat tips comprises a portion having a constant, unaltered thickness. [7] The filter element of claim 1, wherein a thicker media portion is provided that is thicker than the thinner portion, the thinner portion being 20% ​​to 90% thinner than a maximum thickness of the thicker portion. [8] Filter element according to claim 1, wherein the filter medium comprises: a pleat depth extending between the inner pleat tips and the outer pleat tips, between 0.9 and 7.7 centimeters; a maximum thickness between 0.2 and 5.1 millimeters; and The central support tube has an outer diameter between 1 and 40 centimeters. [9] A filter element according to claim 1, wherein the thinner portion remains substantially constant in thickness over a span of the filter media ring, the span being parallel to the pleat tips. [10] The filter element of claim 1, wherein the filter medium is free of embossing and has opposing generally flat surfaces between the pleat tips. [11] Filter element according to claim 1, wherein the thinner portion extends between 5% and 50% of a pleat depth of the pleated layer, and preferably between 10% and 30% of the pleat depth of the pleated layer. [12] The filter element of claim 1, wherein the thinner portion creates space at an inner periphery of the ring to provide larger flow gaps between adjacent inner pleat tips, and / or more filter media with more pleats is used in the ring. [13] Filter element according to claim 1, wherein the thinner section merges into the thicker section, while the thinner section extends radially outward perpendicular to the inner pleat tips. [14] The filter element of claim 1, wherein the pleated layer comprises only a single ply. [15] The filter element of claim 1, wherein the pleated layer comprises a composite having at least two layers comprising a first and a second layer laminated together, the first and second layers having different filtration properties. [16] A filter media web comprising: a pleated filter media layer comprising pleat tips at first and second opposite flow surfaces, the pleated layer comprising a thinner filter media portion extending from the pleat tips at the first flow surface toward the second flow surface and a thicker filter media portion extending from the pleat tips at the second flow surface toward the first flow surface, the thicker portion being thicker than the thinner portion. [17] The filter media web of claim 16, wherein the thinner portion has a minimum thickness that is 20% to 90% thinner than a maximum thickness of the thicker portion. [18] A filter medium web according to claim 16, wherein pleat scores are provided at the pleat tips and the thinner and thicker portions of the filter medium extend from respective pleat scores. [19] The filter media web of claim 16, wherein the filter media has a gradually increasing thickness as the filter media extends from the pleat tips at the first flow surface perpendicular to the pleat tips at the second flow surface. [20] The filter media web of claim 16, wherein the filter media varies incrementally in thickness as the filter media extends from the pleat tips at the first flow surface perpendicular to the pleat tips at the second flow surface. [21] The filter media web of claim 16, wherein the filter media has a gradually increasing tapered thickness over at least one pleat depth segment as the filter media extends from the pleat tips at the first flow surface perpendicular to the pleat tips at the second flow surface. [22] The filter medium web of claim 16, wherein the filter medium comprises: a pleat depth extending between the pleat tips on the first and second flow surfaces of between 0.9 and 7.7 centimeters; a maximum thickness between 0.2 and 5.1 millimeters. [23] The filter media web of claim 16, wherein the thinner portion remains substantially constant in thickness over a span of the filter media web, the span being parallel to the pleat tips. [24] The filter media web of claim 16, wherein the filter media is free of embossing and has opposing generally flat surfaces between the pleat tips. [25] Filter medium web according to claim 16, wherein the thinner portion extends between 5% and 50% of a pleat depth of the pleated layer, and preferably between 10% and 30% of a pleat depth of the pleated layer. [26] A filter element incorporating the filter media web of claim 16, wherein the filter media web is wound into a ring and defines a central cavity, a radially inner periphery of the ring being provided by the pleat tips on the first flow surface and the radially outer periphery of the ring being provided by the pleat tips on the second flow surface spaced radially outwardly from the inner radial periphery. [27] A filter element according to claim 16, wherein the pleated layer comprises only a single ply. [28] The filter element of claim 16, wherein the pleated layer comprises a composite having at least two layers comprising a first and a second layer laminated together, the first and second layers having different filtration properties. [29] A method of producing a filter media package comprising: Creating thicker and thinner sections of a filter media web, the thicker sections being thicker than the thinner sections; Folding the filter medium web at the thinner sections; Folding the filter media web at the thicker sections, creating pleats between folds at the thinner and thicker sections; Winding the filter media pack into an annular shape with the thinner sections at an inner radial circumference and thicker sections at the outer radial circumference. [30] The method of claim 29, further comprising scoring the filter media pack at first scores between the thinner sections and second scores between the thicker sections, wherein folding is facilitated along the first and second scores. [31] A method according to claim 29, further comprising: Conveying the filter media web along a feed path to a plate forming press or cooperating rollers; Compressing the filter media web with the plate forming press or the cooperating rollers to reduce a thickness of the filter media web over a region between 5% and 50% of a pleat depth of the pleats, and more preferably between 10% and 30% of the pleat depth between 20% and 90%. [32] A method according to claim 31, wherein the method employs the cooperating rollers with an eccentric therebetween which compresses the filter medium web to a variable thickness. [33] The method of claim 29, wherein the plate forming press is used, wherein the plate forming press includes a variable thickness gap between opposing plates that compresses the filter media web along the pleats to a variable thickness between folds.

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