High efficiency filtration media

Abstract

Filter media packs, filter elements, and media are disclosed that include a media pack having a plurality of single facer media layers, where the single facer media layers include a fluted sheet, a surface sheet, and a plurality of flutes extending between the fluted sheet and the surface sheet, where the fluted sheet and surface sheet are formed of a multi-layer media that can include a layer of polytetrafluoroethylene (PTFE) supported by a layer of polymer scrim.

Description

[0001] This application was filed on March 24, 2021, as a PCT international patent application in the name of Donaldson Company, Inc. (a U.S. national corporation, designated applicant in all countries) and Rakesh K. Yadav, Indian citizen; Daniel L. Tuma, U.S. citizen; Robert R. Levac, U.S. citizen; Byron G. Griffin, U.S. citizen; Jonathan M. Beckett, U.S. citizen; Anil Suthar, Indian citizen; and Robert J. Pannepacker, Jr., U.S. citizen (designated inventors in all countries), and claims priority to U.S. Provisional Patent Application No. 62 / 994,262, filed March 24, 2020, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0002] The embodiments described herein relate to filter media, filter media packages, and filter elements. Background Technology

[0003] High-efficiency filtration, including high-efficiency particulate air (HEPA) filtration, is desired for many applications, especially those that wish to remove various small particles, including but not limited to particles from engine combustion, fire, dust, microorganisms and other pathogens, viruses, etc. For example, HEPA filtration is often desired for the air circulating in an aircraft cabin.

[0004] Despite the availability of various HEPA filtration products, there is still a need for improved HEPA filter media, media packs, and filter elements. Summary of the Invention

[0005] This application relates to filter media, filter media packs, and filter elements. In an embodiment, the filter media pack has multiple single-sided media layers, wherein the multiple single-sided media layers include a grooved sheet, a surface sheet, and multiple grooves extending between the grooved sheet and the surface sheet, and the multiple grooves have a groove length extending from a first side of the filter media pack to a second side of the filter media pack. A first portion of the multiple grooves is closed for unfiltered fluid flowing into the first portion of the multiple grooves, and a second portion of the multiple grooves is closed for unfiltered fluid flowing out of the second portion of the multiple grooves, such that fluid entering one of the first or second sides of the media pack and exiting the other of the first or second side of the media pack passes through the media to provide filtration of the fluid. The grooved sheet and the surface sheet are formed of a multilayer media that may include a polytetrafluoroethylene (PTFE) layer supported by a loosely woven polymer fabric.

[0006] Generally, a relatively uniform polymer sparse layer is desirable in terms of surface irregularities (such as fiber peak height relative to surrounding fibers), fiber diameter, and fiber distribution. This relative uniformity allows for improved support of the PTFE layer, which is typically very thin and relatively fragile.

[0007] The maximum peak height of the polymer sparse fabric layer is therefore preferably relatively small. In the embodiments, the polymer sparse fabric layer has an external maximum peak height S of less than 5 µ - 100 µ, measured between the highest peak and the average plane. P .

[0008] Alternatively, in the embodiments, the polymer sparse layer has an external maximum peak height S greater than 5 µm measured between the highest peak and the average plane. P In an embodiment, the polymer sparse layer has an external maximum peak height S of less than 100 µm, measured between the highest peak and the average plane. P .

[0009] In the embodiment, the polymer sparse fabric layer has an external maximum peak height S of less than 80 µm, measured between the highest peak and the average plane. P In an embodiment, the polymer sparse fabric layer has an external maximum peak height S of less than 60 µm, measured between the highest peak and the average plane. P In an embodiment, the polymer sparse fabric layer has an external maximum peak height S of less than 50 µm, measured between the highest peak and the average plane. P In an embodiment, the polymer sparse fabric layer has an external maximum peak height S of less than 40 µm, measured between the highest peak and the average plane. P In an embodiment, the polymer sparse fabric layer has an external maximum peak height S of less than 30 µm, measured between the highest peak and the average plane. P In an embodiment, the polymer sparse fabric layer has an external maximum peak height S of less than 20 µm, measured between the highest peak and the average plane. P .

[0010] In the embodiment, the polymer sparse fabric layer has an external root-mean-square height S of less than 100 µ according to the following formula. q : , In the embodiments, the polymer sparse fabric layer has an external root-mean-square height S of less than 75 µm, less than 50 µm, less than 40 µm, less than 35 µm, or less than 20 µm. q .

[0011] In the embodiment, the polymer sparse fabric layer has an external arithmetic mean height S of less than 100 µ according to the following formula. a : , In the embodiment, the polymer sparse fabric layer has an external arithmetic mean height S of less than 75 µm. a The polymer-sparse fabric layer has an external arithmetic mean height S of less than 60 µ. a The polymer-sparse fabric layer has an external arithmetic mean height S of less than 50 µm. a The polymer-sparse fabric layer has an external arithmetic mean height S of less than 40 µ. a The polymer-sparse fabric layer has an external arithmetic mean height S of less than 30µ. a Alternatively, the polymer sparse fabric layer has an external arithmetic mean height S of less than 20 µm. a .

[0012] Typically, it is desirable for the polymer sparse fabric layer to have a relatively uniform fiber distribution. In the embodiments, the polymer sparse fabric layer has fibers with a distribution uniformity of -1.0 to -0.25, measured as the average density difference, as determined by the following formula: , According to Rajev Chhabra, “Nonwoven Uniformity – Measurement Using Image Analysis”, INJ, Spring 2003, p. 50, which is incorporated herein by reference.

[0013] In one embodiment, the polymer sparse fabric layer has fibers with a distribution uniformity of -1 to -0.5. In another embodiment, the polymer sparse fabric layer has fibers with a distribution uniformity greater than -1.5; alternatively, the polymer sparse fabric layer has fibers with a distribution uniformity greater than -2.0; alternatively, the polymer sparse fabric layer has fibers with a distribution uniformity greater than -3.0.

[0014] In the embodiments, the polymer sparse fabric layer has fibers with a contact point uniformity of less than 2.0, less than 1.5, less than 1.0, or less than 1.0. In the embodiments, the polymer sparse fabric layer has fibers with a contact point uniformity of 0.5 to 2.5. In the embodiments, the polymer sparse fabric layer has fibers with a contact point uniformity of 1.0 to 2.0. The contact point uniformity can be measured according to the following: Mina Emadi et al., MEASUREMENT OF THE UNIFORMITY OF THERMALLY BONDED POINTS IN POLYPROPYLENE SPUNBONDED NON-WOVENS USING IMAGE PROCESSING AND ITSRELATIONSHIP WITH THEIRTENSILE PROPERTIES, AUTEX Research Journal, Vol. 18, No. 4, December 2018 (incorporated herein by reference).

[0015] In one embodiment, the multilayer medium has an air permeability of 2.0 to 3.0 cubic feet per minute (CFM); in another embodiment, the multilayer medium has an air permeability of 1.5 to 4.0 cubic feet per minute (CFM); in yet another embodiment, the multilayer medium has an air permeability of 1.0 to 5.0 cubic feet per minute (CFM); in yet another embodiment, the multilayer medium has an air permeability of 0.5 to 6.0 cubic feet per minute (CFM); in yet another embodiment, the multilayer medium has an air permeability greater than 2.0 cubic feet per minute (CFM); in yet another embodiment, the multilayer medium has an air permeability greater than 2.5 cubic feet per minute (CFM); in yet another embodiment, the multilayer medium has an air permeability greater than 3.0 cubic feet per minute (CFM); in yet another embodiment, the multilayer medium has an air permeability greater than 4.0 cubic feet per minute (CFM); and in yet another embodiment, the multilayer medium has an air permeability greater than 5.0 cubic feet per minute (CFM).

[0016] In one embodiment, the filter pack achieves an efficiency of 99.97% for 3-micron particles at a flow rate of 1200 cfm through the media pack. In another embodiment, the filter pack achieves an efficiency of 99.97% for 3-micron particles at a flow rate of 800 cfm through the media pack. In yet another embodiment, the filter pack achieves an efficiency of 99.97% for 3-micron particles at a flow rate of 1600 cfm through the media pack. In yet another embodiment, the filter pack achieves an efficiency of 99.97% for 3-micron particles at a flow rate of 2400 cfm through the media pack. In yet another embodiment, the filter pack achieves an efficiency of 99.97% for 3-micron particles at a flow rate of 3000 cfm through the media pack.

[0017] In one embodiment, the filter pack has an efficiency of 99.97% for 3-micron particles at a surface velocity of 5 to 25 feet per minute. In another embodiment, the filter pack has an efficiency of 99.97% for 3-micron particles at a surface velocity of 5 feet per minute. In yet another embodiment, the filter pack has an efficiency of 99.97% for 3-micron particles at a surface velocity of 10 feet per minute. In yet another embodiment, the filter pack has an efficiency of 99.97% for 3-micron particles at a surface velocity of 15 feet per minute. In yet another embodiment, the filter pack has an efficiency of 99.97% for 3-micron particles at a surface velocity of 20 feet per minute. In yet another embodiment, the filter pack has an efficiency of 99.97% for 3-micron particles at a surface velocity of 25 feet per minute. In yet another embodiment, the filter pack has an efficiency of 99.97% for 3-micron particles at a surface velocity of 30 feet per minute.

[0018] In one embodiment, the multilayer dielectric has a thickness of 6 to 9 mils. In another embodiment, the multilayer dielectric has a thickness of 5 to 10 mils. In yet another embodiment, the multilayer dielectric has a thickness of 4 to 11 mils. In a third embodiment, the multilayer dielectric has a thickness of 3 to 15 mils. In yet another embodiment, the multilayer dielectric has a thickness of less than 22 mils, less than 15 mils, less than 12 mils, less than 9 mils, less than 7 mils, less than 6 mils, or less than 5 mils.

[0019] In one embodiment, the multilayer medium has a foaming point of 6 to 10 psi. In another embodiment, the multilayer medium has a foaming point of 5 to 11 psi. In yet another embodiment, the multilayer medium has a foaming point of 4 to 12 psi.

[0020] In this embodiment, PTFE includes expanded PTFE (ePTFE).

[0021] In the examples, PTFE has an average pore size of 1.0 to 5.0 micrometers.

[0022] In one embodiment, the polymer spunbond fabric comprises spunbond fibers. In another embodiment, the spunbond fibers comprise polyester fibers.

[0023] In the embodiments, the fibers are distributed substantially uniformly.

[0024] In one embodiment, the polymer sparse fabric layer has a basis weight of 0.5 to 1.0 oz / yard square. In another embodiment, the polymer sparse fabric layer has a basis weight of 0.6 to 0.9 oz / yard square. In yet another embodiment, the polymer sparse fabric layer has a basis weight greater than 0.5 oz / yard square. In yet another embodiment, the polymer sparse fabric layer has a basis weight less than 1.5 oz / yard square. In yet another embodiment, the polymer sparse fabric layer has a basis weight less than 2.0 oz / yard square.

[0025] In one embodiment, the polymer sparse fabric layer has a thickness of 6 mils. In another embodiment, the polymer sparse fabric layer has a thickness of 4 to 8 mils. In another embodiment, the polymer sparse fabric layer has a thickness of 3 to 10 mils. In another embodiment, the polymer sparse fabric layer has a thickness of less than 12 mils. In another embodiment, the polymer sparse fabric layer has a thickness of less than 14 mils. In another embodiment, the polymer sparse fabric layer has a thickness of less than 16 mils.

[0026] In the embodiments, the loosely woven polymer fabric layer has a strength of 800 to 900 cfm / ft at 0.5 inches of water. 2 Frazier air permeability. In examples, the loosely woven polymer fabric has 700 to 1,000 cfm / ft in 0.5 inches of water. 2 Fraser air permeability. In examples, the polymer-sparse fabric layer has 600 to 1,100 cfm / ft in 0.5 inches of water. 2 Fraser air permeability. In examples, the polymer-sparse fabric layer has 550 to 1,050 cfm / ft in 0.5 inches of water. 2 Fraser air permeability. In the examples, the loosely woven polymer fabric has 500 to 1,500 cfm / ft in 0.5 inches of water. 2 Fraser air permeability. In the example, the loosely woven polymer fabric has a permeability greater than 500 cfm / ft in 0.5 inches of water. 2 Fraser air permeability. In the example, the loosely woven polymer fabric has a permeability greater than 700 cfm / ft in 0.5 inches of water. 2 Fraser air permeability. In the example, the polymer sparse fabric layer has a permeability greater than 900 cfm / ft at 0.5 inches of water. 2 Fraser air permeability.

[0027] In one embodiment, the fibers are substantially uniformly distributed such that the standard deviation of the fiber spacing is from 0.5 to 1.0. In another embodiment, the fibers are substantially uniformly distributed such that the standard deviation of the fiber spacing is from 0.6 to 0.9. In yet another embodiment, the fibers are substantially uniformly distributed such that the standard deviation of the fiber spacing is from 0.7 to 0.8. In yet another embodiment, the fibers are substantially uniformly distributed such that the standard deviation of the fiber spacing is from 0.25 to 1.0.

[0028] In an embodiment, the filter medium may further include an additional layer between the PTFE layer and the polymer sparse cloth layer. In an embodiment, the additional layer comprises polypropylene or polyethylene. In an embodiment, the polymer sparse cloth layer further comprises cellulose.

[0029] In one embodiment, PTFE has a thickness of 6 to 10 mils. In another embodiment, PTFE has a thickness of 4 to 12 mils. In yet another embodiment, PTFE has a thickness of 7 to 9 mils. In a third embodiment, PTFE has a thickness of 2 to 14 mils. In yet another embodiment, PTFE has a thickness of 5 to 10 mils. In yet another embodiment, PTFE has a thickness greater than 4 mils. In yet another embodiment, PTFE has a thickness greater than 5 mils. In yet another embodiment, PTFE has a thickness greater than 6 mils. In yet another embodiment, PTFE has a thickness greater than 7 mils.

[0030] In one embodiment, PTFE has a thickness of less than 9 mils. In another embodiment, PTFE has a thickness of less than 10 mils. In yet another embodiment, PTFE has a thickness of less than 12 mils. In yet another embodiment, PTFE has a thickness of less than 15 mils. In yet another embodiment, PTFE has a thickness of less than 20 mils.

[0031] In the embodiments, PTFE has a strength of 200 to 300 cfm / ft. 2 The air permeability. In examples, PTFE has an air permeability of 150 to 350 cfm / ft. 2 The air permeability. In examples, PTFE has an air permeability of 100 to 400 cfm / ft. 2 The air permeability. In examples, PTFE has an air permeability of 500 to 500 cfm / ft. 2 The air permeability. In the examples, PTFE has an air permeability greater than 100 cfm / ft. 2 Air permeability.

[0032] In the embodiment, PTFE has a strength greater than 125 cfm / ft. 2 The air permeability. In the embodiment, PTFE has a permeability greater than 150 cfm / ft. 2 The air permeability. In the embodiment, PTFE has a permeability greater than 200 cfm / ft.2 The air permeability. In the embodiment, PTFE has a permeability greater than 225 cfm / ft. 2 The air permeability. In the embodiment, PTFE has a permeability of less than 275 cfm / ft. 2 Air permeability: less than 300 cfm / ft 2 Air permeability: less than 350 cfm / ft 2 Air permeability: less than 400 cfm / ft 2 Air permeability: less than 500 cfm / ft 2 Air permeability; or less than 1000 cfm / ft 2 Air permeability.

[0033] In some embodiments, PTFE has a mullen burst strength of 25 to 75 psi; alternatively, in some embodiments, PTFE has a mullen burst strength of 10 to 90 psi; 10 to 100 psi; less than 125 psi; less than 150 psi; or less than 200 psi.

[0034] In one embodiment, PTFE has a strip tensile strength of 60 / 48 (MD / CD, kg / 5 cm). Alternatively, in another embodiment, PTFE has a strip tensile strength of 40 to 80 / 40 to 60 (MD / CD, kg / 5 cm); alternatively, in another embodiment, PTFE has a strip tensile strength of 30 to 90 / 30 to 70 (MD / CD, kg / 5 cm); and alternatively, in another embodiment, PTFE has a strip tensile strength of 20 to 100 / 20 to 80 (MD / CD, kg / 5 cm).

[0035] In one embodiment, PTFE has a base weight of 1.0 to 3.0 oz / yard square; alternatively, in another embodiment, PTFE has a base weight of 1.5 to 2.5 oz / yard square. In another embodiment, PTFE has a base weight of 0.5 to 3.0 oz / yard square; alternatively, PTFE has a base weight greater than 0.5 oz / yard square. In yet another embodiment, PTFE has a base weight greater than 1.0 oz / yard square, greater than 1.5 oz / yard square, less than 3.0 oz / yard square, less than 4.0 oz / yard square, or less than 5.0 oz / yard square.

[0036] This invention provides an overview of some of the teachings of this application and is not intended to be exclusive or exhaustive of the subject matter. Further details can be found in the detailed description and the appended claims. Other aspects will be apparent to those skilled in the art after reading and understanding the following detailed description and reviewing the accompanying drawings, which form a part of the detailed description, and none of these aspects should be considered limiting. The scope of this document is defined by the appended claims and their legal equivalents. Attached Figure Description

[0037] A more comprehensive understanding of the various aspects can be achieved by referring to the following attached figures (Figures):

[0038] Figure 1 This is a perspective view of a portion of a single-sided z-flow medium made according to the various embodiments described herein.

[0039] Figure 2 This is a cross-sectional view of a portion of a single-sided z-flow medium made according to the various embodiments described herein.

[0040] Figure 3 This is a schematic cross-sectional view of a two-layer medium component manufactured according to the various embodiments described herein.

[0041] Figure 4 This is a schematic cross-sectional view of a three-layer medium according to the various embodiments described herein.

[0042] Figure 5 This is a perspective view of the filter element according to the various embodiments herein.

[0043] Figure 6 According to the various embodiments herein Figure 5 The front view of the filter element.

[0044] Figure 7 This is a graph showing the relative performance between z-flow media containing an ePTFE layer and pleated HEPA media.

[0045] Figure 8 This is a close-up illustration of a programmed filter medium, showing fibers of various diameters.

[0046] Figure 9 yes Figure 8 The diagrams show the respective targets. Figure 10 , 11 The three specific areas A, B, and C in the close-up view in 12.

[0047] Figure 10 It comes from Figure 9 A close-up of region A.

[0048] Figure 11 It comes from Figure 9 A close-up of region B.

[0049] Figure 12 It comes from Figure 9 A close-up of region C.

[0050] Figure 13 This is a close-up illustration of a programmed filter medium, showing fibers of substantially uniform diameter, and also showing a specific area A.

[0051] Figure 14 It comes from Figure 13 A close-up of region A.

[0052] Figure 15 This is a close-up illustration of a programmed filter medium, showing fibers of substantially uniform diameter, and also showing a specific area A.

[0053] Figure 16 It comes from Figure 15 A close-up of region A.

[0054] Figure 17 This is a close-up illustration of a programmed filter medium.

[0055] Figure 18 This is an illustration of a close-up side cross-sectional view of a polymer sparse fabric, showing aspects of the maximum and minimum height of the top surface.

[0056] Figure 19 It comes from Figure 18 A close-up of detail 19.

[0057] Figure 20 This is a diagram showing the height of the top surface of the PTFE.

[0058] Figure 21 It comes from Figure 20 A close-up of detail 21.

[0059] While the embodiments are susceptible to various modifications and alternatives, their details have been illustrated by example and accompanying drawings and will be described in detail. However, it should be understood that the scope of this document is not limited to the specific aspects described. Rather, the aim is to cover modifications, equivalents, and alternatives that fall within the spirit and scope of this document. Detailed Implementation

[0060] Figure 1This is a perspective view of a portion of a one-sided z-flow medium 110 manufactured according to various embodiments herein. The one-sided z-flow medium 110 includes a grooved sheet 112 and a surface sheet 114. The grooved sheet 112 includes a plurality of grooves 113 extending from one end of the one-sided sheet to the other. Adhesive beads 116 or other obstructions are located at one end of the one-sided z-flow medium 110 and obstruct gas flow, forcing them to enter specific grooves. Arrow 118 illustrates unfiltered air entering the grooves of the one-sided z-flow medium 110 and then passing through these grooves (as shown at arrow 120) and traveling along the outside of the grooves (as shown at arrow 122).

[0061] Figure 2 This is a cross-sectional view of a portion of a one-sided z-flow medium 110 manufactured according to various embodiments herein. The one-sided z-flow medium 110 includes a grooved sheet 112 and a surface sheet 114 with grooves 113. The grooved sheet 112 includes an inner surface 226, and the surface sheet 114 includes an inner surface 224. These inner surfaces 224 and 226 typically include a layer of expanded polytetrafluoroethylene (PTFE) fixed to a supporting loose fabric. The inner surfaces 224 and 226 are generally located on the upstream side of the one-sided medium (and thus on the side receiving unfiltered air).

[0062] Figure 3 This is a schematic cross-sectional view of a two-layer media member 330 made according to various embodiments herein. The two-layer media member 330 includes a support sparse fabric 334 and an ePTFE layer 332. The surface 338 of the ePTFE layer typically forms the interior of a groove for receiving unfiltered air; while the surface 336 of the support sparse fabric 334 is located downstream of the filter. It should be understood that both the grooved sheet and the surface sheet typically use the same media (see...). Figure 1 and Figure 2 ).

[0063] Figure 4 This is a schematic cross-sectional view of the three-layer medium 440 according to the various embodiments herein. Figure 3 In the middle, the supporting loose fabric 444 and the ePTFE layer 442 are fixed to each other by additional layers 450 such as polypropylene or polyethylene layers.

[0064] Figure 5 This is a perspective view of a filter element 550 according to various embodiments herein, the filter element 550 including a filter media package. The filter element 550 includes a top 552, a bottom 554, a first side 556, and a second side 558. The filter element 550 further includes a front portion 560 and a back portion 562. The front portion 560 includes an exposed surface 564 of the front portion of the flow medium, which continues through the filter element 550 to the back portion 562. Figure 6 According to the various embodiments herein Figure 5 The front view of the filter element 550.

[0065] Figure 7 It is a graph showing the relative performance between media containing an ePTFE layer and those without an ePTFE layer. Figure 5 This demonstrates how HEPA z-flow media has a longer lifespan than the example pleated media.

[0066] Figure 8 This is a close-up illustration (not a photograph) of the programmed filter media 810, showing fibers of various diameters used for the polymer sparse cloth support material. In the depicted diagram, there are fine fibers 820, medium fibers 830, and coarse fibers 840. Generally, it is desirable to have fibers with relatively uniform dimensions. Dimensional uniformity allows for better support of the PTFE layer, which maintains the integrity of the PTFE layer and prevents its degradation. In the embodiments, the polymer sparse cloth layer has fibers with an average diameter of 10 to 20 µm and a standard deviation of less than 3 µm; alternatively, the polymer sparse cloth layer has fibers with an average diameter of 5 to 25 µm and a standard deviation of less than 4 µm; alternatively, the polymer sparse cloth layer has fibers with an average diameter of 12 to 18 µm and a standard deviation of less than 2 µm. Alternatively, the polymer sparse cloth layer has fibers with a standard deviation of less than 5 µm, less than 4 µm, less than 3 µm, or less than 2 µm.

[0067] Figure 9 yes Figure 8 The diagrams show the respective targets. Figure 10 , 11 The three specific areas A, B, and C in the close-up view in 12. Figure 9 Specifically, medium 810 is shown, in which three regions A, B, and C are superimposed on filter medium 810. In this case, medium 810 is a polymer sparse cloth medium.

[0068] Fiber diameter can be measured by selecting a region (such as region A, region B, or region C) and then measuring the number of fibers and the diameter of each fiber in that region to obtain the average fiber diameter. Other statistical measurements, such as median fiber diameter, mode fiber diameter, standard deviation, etc., are also permitted. The size of the region used for these measurements can be adjusted, but should generally be large enough to allow for a statistically significant sample size. Typically, at least 20 fibers should be shown in the measurement region, more typically at least 30, 40, or 50 fibers. Larger sample sizes, such as 50 to 500 fibers, 50 to 250 fibers, or 50 to 100 fibers, can also be used. Furthermore, multiple measurements can be performed across multiple regions, and the results can then be combined, such as combining regions A, B, and C and averaging the results. Generally, it is desirable to attempt to have a sufficiently large sample size to accurately characterize the overall media properties.

[0069] Please note that it is generally desirable to measure fiber dimensions from the non-laminated side of the medium; in other words, from the side of the medium that does not contain PTFE, as this non-laminated side of the medium will have visible fibers not obscured by PTFE. Additionally, the element can be disassembled and samples taken from exposed areas of the medium, such as portions of a flat sheet forming the medium, or portions of a wrinkled medium that have been flattened. It should be understood that not all portions of the medium in a medium package or element need to meet the fiber diameter (or other parameter) requirement; only a portion of the medium must meet it. Typically, most media will meet the requirement, and in some cases, all media will meet these requirements, but in other cases, only a smaller fraction of the media will meet them.

[0070] Figure 10 It comes from Figure 9 A close-up of region A, which shows small fiber 1020, medium fiber 1030 and large fiber 1040.

[0071] Figure 11 It comes from Figure 9 A close-up of region B shows small fiber 1120, medium fiber 1130, and large fiber 1140. For illustrative purposes, each fiber is labeled, with four small fibers labeled 1120; six medium fibers labeled 1130; and one large fiber labeled 1140. Fibers appearing anywhere in the region are counted. If a fiber is continuous but leaves and re-enters the measurement area, it can be counted as two fibers. In this example, assuming small fiber 1120 is 10 micrometers, medium fiber 1130 is 20 micrometers, and large fiber 1140 is 30 micrometers, the average diameter would be 17.3 micrometers.

[0072] Figure 12 It comes from Figure 9 A close-up of region C, which shows small fibers 1220; medium fibers 1230 and large fibers 1240.

[0073] Figure 13 This is a close-up illustration of the programmed filter media 1320, showing fibers of substantially uniform diameter, and also showing a specific area A. Figure 14 This is a close-up of region A. In some embodiments, fiber size uniformity is desirable because uniform fiber size can provide improved support for the PTFE layer.

[0074] Figure 15 This is a close-up illustration of the programmed filter media 1510, which shows small fibers 1520 of substantially uniform diameter, and also shows a specific area A. Figure 16 It comes from Figure 15A close-up of region A. The close-up of region A also shows contact point 1625, where two fibers intersect and contact each other. In one embodiment, the polymer sparse fabric layer has fibers with a contact point uniformity of less than 2.0, less than 1.5, less than 1.0, or less than 1.0. In another embodiment, the polymer sparse fabric layer has fibers with a contact point uniformity of 0.5 to 2.5. In yet another embodiment, the polymer sparse fabric layer has fibers with a contact point uniformity of 1.0 to 2.0.

[0075] Figure 17 This is a close-up illustration of filter media 1710, showing an example first region 1770 and a second region 1780. Compared to the second region 1780, the first region 1770 has a significantly more uniform distribution of polymer sparse fibers, and this more uniform distribution is desirable. In the embodiment, the polymer sparse layer has fibers with a distribution uniformity of -1.0 to -0.25 for the average density difference, as measured by the following formula: , In one embodiment, the polymer sparse fabric layer has fibers with a distribution uniformity of -1 to -0.5. In another embodiment, the polymer sparse fabric layer has fibers with a distribution uniformity greater than -1.5; in yet another embodiment, the polymer sparse fabric layer has fibers with a distribution uniformity greater than -2.0; in yet another embodiment, the polymer sparse fabric layer has fibers with a distribution uniformity greater than -3.0; and in yet another embodiment, the polymer sparse fabric layer has fibers with a contact point uniformity less than 3.0.

[0076] Figure 18 This is an illustration of a close-up side cross-sectional view of polymer sparse cloth 1810, which shows aspects of the maximum and minimum height of the top surface 1812. Figure 19 It comes from Figure 18 A close-up of detail 19 shows the minimum height 1925 and the maximum height 1935 of the top surface. The average height of the example is also shown. In this embodiment, the loosely woven polymer layer has an external maximum peak height S of less than 5 µ - 100 µ, measured between the highest peak and the average plane. P Alternatively, in the embodiments, the polymer sparse layer has an external maximum peak height S greater than 5 µm measured between the highest peak and the average plane. P .

[0077] In the embodiment, the polymer sparse fabric layer has an external maximum peak height S of less than 100 µm, measured between the highest peak and the average plane. P In an embodiment, the polymer sparse fabric layer has an external maximum peak height S of less than 80 µm, measured between the highest peak and the average plane. PIn an embodiment, the polymer sparse fabric layer has an external maximum peak height S of less than 60 µm, measured between the highest peak and the average plane. P In an embodiment, the polymer sparse fabric layer has an external maximum peak height S of less than 50 µm, measured between the highest peak and the average plane. P In an embodiment, the polymer sparse fabric layer has an external maximum peak height S of less than 40 µm, measured between the highest peak and the average plane. P In an embodiment, the polymer sparse fabric layer has an external maximum peak height S of less than 30 µm, measured between the highest peak and the average plane. P In an embodiment, the polymer sparse fabric layer has an external maximum peak height S of less than 20 µm, measured between the highest peak and the average plane. P .

[0078] In the embodiment, the polymer sparse fabric layer has an external root-mean-square height S of less than 100 µ according to the following formula. q : , In the embodiments, the polymer sparse fabric layer has an external root-mean-square height S of less than 75 µm, less than 50 µm, less than 40 µm, less than 35 µm, or less than 20 µm. q In an embodiment, the polymer sparse fabric layer has an external arithmetic mean height S of less than 100 µ according to the following formula. a : , In the embodiment, the polymer sparse fabric layer has an external arithmetic mean height S of less than 75 µm. a The polymer-sparse fabric layer has an external arithmetic mean height S of less than 60 µ. a The polymer-sparse fabric layer has an external arithmetic mean height S of less than 50 µm. a The polymer-sparse fabric layer has an external arithmetic mean height S of less than 40 µ. a The polymer-sparse fabric layer has an external arithmetic mean height S of less than 30µ. a Alternatively, the polymer sparse fabric layer has an external arithmetic mean height S of less than 20 µm. a .

[0079] Figure 20 This is a diagram showing the height of the PTFE top surface at 2060, and Figure 21 It comes from Figure 20 A close-up of detail 21. It shows the maximum peak, the minimum valley, and the average value.

[0080] In an embodiment, the filter media package includes: (a) a plurality of single-sided media layers, wherein the single-sided media layers include a grooved sheet, a surface sheet, and a plurality of grooves extending between the grooved sheet and the surface sheet, and the plurality of grooves having a groove length extending from a first side of the filter media package to a second side of the filter media package; (b) a first portion of the plurality of grooves is closed to unfiltered fluid flowing into the first portion of the plurality of grooves, and a second portion of the plurality of grooves is closed to unfiltered fluid flowing out of the second portion of the plurality of grooves, such that fluid entering one of the first side or the second side of the media package and exiting the other of the first side or the second side of the media package passes through the media to provide filtration of the fluid; wherein the grooved sheet and the surface sheet are formed of a multilayer media comprising a polytetrafluoroethylene (PTFE) layer supported by a polymer sparse fabric layer.

[0081] In one embodiment, the multilayer medium has an air permeability of 2.0 to 3.0 cubic feet per minute (CFM). In another embodiment, the multilayer medium has an air permeability of 1.5 to 4.0 cubic feet per minute (CFM). In yet another embodiment, the multilayer medium has an air permeability of 1.0 to 5.0 cubic feet per minute (CFM). In yet another embodiment, the multilayer medium has an air permeability of 0.5 to 6.0 cubic feet per minute (CFM). In yet another embodiment, the multilayer medium has an air permeability greater than 2.0 cubic feet per minute (CFM). In yet another embodiment, the multilayer medium has an air permeability greater than 2.5 cubic feet per minute (CFM). In yet another embodiment, the multilayer medium has an air permeability greater than 3.0 cubic feet per minute (CFM). In yet another embodiment, the multilayer medium has an air permeability greater than 4.0 cubic feet per minute (CFM). In yet another embodiment, the multilayer medium has an air permeability greater than 5.0 cubic feet per minute (CFM).

[0082] In one embodiment, the filter pack achieves 99.97% efficiency for 3-micron particles at a flow rate of 1200 cfm through the media pack. In another embodiment, the filter pack achieves 99.97% efficiency for 3-micron particles at a flow rate of 800 cfm through the media pack. In yet another embodiment, the filter pack achieves 99.97% efficiency for 3-micron particles at a flow rate of 1600 cfm through the media pack. In yet another embodiment, the filter pack achieves 99.97% efficiency for 3-micron particles at a flow rate of 2400 cfm through the media pack. In yet another embodiment, the filter pack achieves 99.97% efficiency for 3-micron particles at a flow rate of 3000 cfm through the media pack. In yet another embodiment, the filter pack achieves 99.97% efficiency for 3-micron particles at surface velocities of 5 to 25 feet per minute.

[0083] In one embodiment, the filter pack has an efficiency of 99.97% for 3-micron particles at a surface velocity of 5 feet per minute. In another embodiment, the filter pack has an efficiency of 99.97% for 3-micron particles at a surface velocity of 10 feet per minute. In yet another embodiment, the filter pack has an efficiency of 99.97% for 3-micron particles at a surface velocity of 15 feet per minute. In yet another embodiment, the filter pack has an efficiency of 99.97% for 3-micron particles at a surface velocity of 20 feet per minute. In yet another embodiment, the filter pack has an efficiency of 99.97% for 3-micron particles at a surface velocity of 25 feet per minute.

[0084] In one embodiment, the filter pack has an efficiency of 99.97% for 3-micron particles at a surface velocity of 30 feet per minute. In another embodiment, the multilayer media has a thickness of 6 to 9 mils. In yet another embodiment, the multilayer media has a thickness of 5 to 10 mils. In yet another embodiment, the multilayer media has a thickness of 4 to 11 mils. In yet another embodiment, the multilayer media has a thickness of 3 to 15 mils. In yet another embodiment, the multilayer media has a thickness of less than 20 mils. In yet another embodiment, the multilayer media has a thickness of less than 20 mils. In yet another embodiment, the multilayer media has a thickness of less than 15 mils.

[0085] In one embodiment, the multilayer medium has a thickness of less than 12 mils. In another embodiment, the multilayer medium has a thickness of less than 9 mils. In another embodiment, the multilayer medium has a thickness of less than 7 mils. In another embodiment, the multilayer medium has a thickness of less than 6 mils. In another embodiment, the multilayer medium has a thickness of less than 5 mils. In another embodiment, the multilayer medium has a foaming point of 6 to 10 psi. In another embodiment, the multilayer medium has a foaming point of 5 to 11 psi. In another embodiment, the multilayer medium has a foaming point of 4 to 12 psi.

[0086] In this embodiment, PTFE includes expanded PTFE (ePTFE).

[0087] In the examples, PTFE has an average pore size of 1.0 to 5.0 micrometers.

[0088] In one embodiment, the polymer sparse fabric comprises spunbond fibers. In another embodiment, the spunbond fibers comprise polyester fibers.

[0089] In one embodiment, the fibers are substantially uniformly distributed. In another embodiment, the polymer sparse fabric layer has a basis weight of 0.5 to 1.0 oz / yard square. In another embodiment, the polymer sparse fabric layer has a basis weight of 0.6 to 0.9 oz / yard square. In yet another embodiment, the polymer sparse fabric layer has a basis weight greater than 0.5 oz / yard square. In yet another embodiment, the polymer sparse fabric layer has a basis weight less than 1.5 oz / yard square.

[0090] In the embodiments, the polymer sparse fabric layer has a basis weight of less than 2.0 ounces / square yard.

[0091] In the embodiment, the polymer sparse fabric layer has a thickness of 6 mils.

[0092] In one embodiment, the polymer sparse fabric layer has a thickness of 4 to 8 mils. In another embodiment, the polymer sparse fabric layer has a thickness of 3 to 10 mils. In yet another embodiment, the polymer sparse fabric layer has a thickness of less than 12 mils. In yet another embodiment, the polymer sparse fabric layer has a thickness of less than 14 mils. In yet another embodiment, the polymer sparse fabric layer has a thickness of less than 16 mils.

[0093] In one embodiment, the polymer sparse fabric layer has a Fraser air permeability of 800 to 900 cfm / ft² at 0.5 inches of water. In another embodiment, the polymer sparse fabric layer has a permeability of 700 to 1,000 cfm / ft² at 0.5 inches of water. 2 Fraser air permeability. In examples, the polymer-sparse fabric layer has 600 to 1,100 cfm / ft in 0.5 inches of water. 2 Fraser air permeability. In examples, the polymer-sparse fabric layer has 550 to 1,050 cfm / ft in 0.5 inches of water. 2 Fraser air permeability. In the examples, the loosely woven polymer fabric has 500 to 1,500 cfm / ft in 0.5 inches of water. 2 Fraser air permeability. In an example, the polymer sparse fabric layer has a permeability greater than 500 cfm / ft at 0.5 inches of water. 2 Fraser air permeability. In an example, the polymer sparse fabric layer has a permeability greater than 700 cfm / ft in 0.5 inches of water. 2 Fraser air permeability. In an example, the polymer sparse fabric layer has a permeability greater than 900 cfm / ft at 0.5 inches of water. 2 Fraser air permeability.

[0094] In one embodiment, the fibers are substantially uniformly distributed such that the standard deviation of the fiber spacing is from 0.5 to 1.0. In another embodiment, the fibers are substantially uniformly distributed such that the standard deviation of the fiber spacing is from 0.6 to 0.9. In yet another embodiment, the fibers are substantially uniformly distributed such that the standard deviation of the fiber spacing is from 0.7 to 0.8. In yet another embodiment, the fibers are substantially uniformly distributed such that the standard deviation of the fiber spacing is from 0.5 to 1.0. In another embodiment, an additional layer may be included between the PTFE layer and the loosely woven polymer layer. In yet another embodiment, the additional layer comprises polypropylene or polyethylene.

[0095] In one embodiment, the polymer sparse fabric layer further comprises cellulose.

[0096] In one embodiment, PTFE has a thickness of 6 to 10 mils. In another embodiment, PTFE has a thickness of 4 to 12 mils. In yet another embodiment, PTFE has a thickness of 7 to 9 mils. In a third embodiment, PTFE has a thickness of 2 to 14 mils. In yet another embodiment, PTFE has a thickness of 6 to 10 mils. In yet another embodiment, PTFE has a thickness greater than 4 mils. In yet another embodiment, PTFE has a thickness greater than 5 mils.

[0097] In one embodiment, the PTFE has a thickness greater than 6 mils. In another embodiment, the PTFE has a thickness greater than 7 mils. In yet another embodiment, the PTFE has a thickness less than 9 mils. In yet another embodiment, the PTFE has a thickness less than 10 mils.

[0098] In one embodiment, PTFE has a thickness of less than 12 mils. In another embodiment, PTFE has a thickness of less than 15 mils. In another embodiment, PTFE has a thickness of less than 20 mils. In one embodiment, PTFE has an air permeability of 200 to 300 cfm / ft². In another embodiment, PTFE has an air permeability of 150 to 350 cfm / ft². In another embodiment, PTFE has an air permeability of 100 to 400 cfm / ft². In another embodiment, PTFE has an air permeability of 500 to 500 cfm / ft². In another embodiment, PTFE has an air permeability greater than 100 cfm / ft². In another embodiment, PTFE has an air permeability greater than 125 cfm / ft². In another embodiment, PTFE has an air permeability greater than 150 cfm / ft². In another embodiment, PTFE has an air permeability greater than 200 cfm / ft². In another embodiment, PTFE has an air permeability greater than 225 cfm / ft². In one embodiment, PTFE has an air permeability of less than 275 cfm / ft². In another embodiment, PTFE has an air permeability of less than 300 cfm / ft². In another embodiment, PTFE has an air permeability of less than 350 cfm / ft². In another embodiment, PTFE has an air permeability of less than 400 cfm / ft². In another embodiment, PTFE has an air permeability of less than 500 cfm / ft². In another embodiment, PTFE has an air permeability of less than 1000 cfm / ft². In another embodiment, PTFE has a muiron bursting strength of 25 to 75 psi. In another embodiment, PTFE has a muiron bursting strength of 10 to 90 psi. In another embodiment, PTFE has a muiron bursting strength of 10 to 100 psi. In another embodiment, PTFE has a muiron bursting strength of less than 125 psi. In another embodiment, PTFE has a muiron bursting strength of less than 150 psi. In another embodiment, PTFE has a muiron bursting strength of less than 200 psi. In the embodiment, PTFE has a strip tensile strength of 60 / 48 (MD / CD, kg / 5 cm).

[0099] In one embodiment, PTFE has a strip tensile strength (MD / CD, kg / 5 cm) of 40 to 80 / 40 to 60. In another embodiment, PTFE has a strip tensile strength (MD / CD, kg / 5 cm) of 30 to 90 / 30 to 70. In yet another embodiment, PTFE has a strip tensile strength (MD / CD, kg / 5 cm) of 20 to 100 / 20 to 80.

[0100] In one embodiment, PTFE has a base weight of 1.0 to 3.0 oz / yard square. In another embodiment, PTFE has a base weight of 1.5 to 2.5 oz / yard square. In yet another embodiment, PTFE has a base weight of 0.5 to 3.0 oz / yard square. In a third embodiment, PTFE has a base weight greater than 0.5 oz / yard square. In yet another embodiment, PTFE has a base weight greater than 1.0 oz / yard square. In yet another embodiment, PTFE has a base weight greater than 1.5 oz / yard square. In yet another embodiment, PTFE has a base weight less than 3.0 oz / yard square. In yet another embodiment, PTFE has a base weight less than 4.0 oz / yard square. In yet another embodiment, PTFE has a base weight less than 5.0 oz / yard square.

[0101] Further aspects of the subject matter of this invention include the following: 1. In a first embodiment, a filter media package includes: (a) A plurality of single-sided media layers, wherein the single-sided media layer comprises a grooved sheet, a surface sheet, and a plurality of grooves extending between the grooved sheet and the surface sheet, and the plurality of grooves having a groove length extending from a first side of the filter media pack to a second side of the filter media pack. (b) A first portion of the plurality of grooves is closed to unfiltered fluid flowing into the first portion of the plurality of grooves, and a second portion of the plurality of grooves is closed to unfiltered fluid flowing out of the second portion of the plurality of grooves, such that fluid entering one of the first or second surfaces of the medium package and exiting the other of the first or second surfaces of the medium package passes through the medium to provide filtration of the fluid; wherein, The grooved sheet and surface sheet are formed from a multilayer medium including a polytetrafluoroethylene (PTFE) layer supported by a polymer sparse cloth layer. 2. The filter media package as described in any one of Examples 1 and 3-154, wherein the polymer sparse cloth layer has an external maximum peak height S of less than 5 µ - 100 µ measured between the highest peak and the average plane. P . 3. The filter media package as described in any one of Examples 1-2 and 4-154, wherein the loosely woven polymer layer has an external maximum peak height S greater than 5 µm measured between the highest peak and the average plane. P . 4. The filter media package as described in any one of Examples 1-3 and 5-154, wherein the polymer sparse cloth layer has an external maximum peak height S of less than 100 µm measured between the highest peak and the average plane. P . 5. The filter media package as described in any one of Examples 1-4 and 6-154, wherein the polymer sparse cloth layer has an external maximum peak height S of less than 80 µm measured between the highest peak and the average plane. P . 6. The filter media package as described in any one of Examples 1-5 and 7-154, wherein the polymer sparse cloth layer has an external maximum peak height S of less than 60 µm measured between the highest peak and the average plane. P . 7. The filter media package as described in any one of Examples 1-6 and 8-154, wherein the polymer sparse cloth layer has an external maximum peak height S of less than 50 µm measured between the highest peak and the average plane. P . 8. The filter media package as described in any one of Examples 1-7 and 9-154, wherein the polymer sparse cloth layer has an external maximum peak height S of less than 40 µm measured between the highest peak and the average plane. P . 9. The filter media package as described in any one of Examples 1-8 and 10-154, wherein the polymer sparse cloth layer has an external maximum peak height S of less than 30 µm measured between the highest peak and the average plane. P . 10. The filter media package as described in any one of Examples 1-9 and 11-154, wherein the polymer sparse cloth layer has an external maximum peak height S of less than 20 µm measured between the highest peak and the average plane. P . 11. The filter media package as described in any one of Examples 1-10 and 12-154, wherein the polymer sparse cloth layer has an external root-mean-square height S of less than 100 µ according to the following formula. q : . 12. The filter media package as described in any one of Examples 1-11 and 13-154, wherein the polymer sparse cloth layer has an external root-mean-square height S of less than 75 µm according to the following formula. q : . 13. The filter media package as described in any one of Examples 1-12 and 14-154, wherein the polymer sparse cloth layer has an external root-mean-square height S of less than 50 µm according to the following formula. q : . 14. The filter media package as described in any one of Examples 1-13 and 15-154, wherein the polymer sparse cloth layer has an external root-mean-square height S of less than 40 µm according to the following formula. q : . 15. The filter media package as described in any one of Examples 1-14 and 16-154, wherein the polymer sparse cloth layer has an external root-mean-square height S of less than 35 µm according to the following formula. q : . 16. The filter media package as described in any one of Examples 1-15 and 17-154, wherein the polymer sparse cloth layer has an external root-mean-square height S of less than 20 µm according to the following formula. q : . 17. The filter media package as described in any one of Examples 1-16 and 18-154, wherein the polymer sparse cloth layer has an external arithmetic mean height S of less than 100 µ according to the following formula. a : . 18. The filter media package as described in any one of Examples 1-17 and 19-154, wherein the polymer sparse cloth layer has an external arithmetic mean height S of less than 75 µm according to the following formula. a : . 19. The filter media package as described in any one of Examples 1-18 and 20-154, wherein the polymer sparse cloth layer has an external arithmetic mean height S of less than 60 µm according to the following formula. a : . 20. The filter media package as described in any one of Examples 1-19 and 21-154, wherein the polymer sparse cloth layer has an external arithmetic mean height S of less than 50 µm according to the following formula. a : . 21. The filter media package as described in any one of Examples 1-20 and 22-154, wherein the loosely woven polymer fabric has an external arithmetic mean height S of less than 40 µm. a : . 22. The filter media package as described in any one of Examples 1-21 and 23-154, wherein the loosely woven polymer fabric has an external arithmetic mean height S of less than 30 µm. a : . 23. The filter media package as described in any one of Examples 1-22 and 24-154, wherein the loosely woven polymer fabric has an external arithmetic mean height S of less than 20 µm. a : . 24. The filter media package as described in any one of Examples 1-23 and 25-154, wherein the polymer sparse cloth layer has fibers with an average diameter of 10 to 20 µ and a standard deviation of less than 5 µ. 25. The filter media package as described in any one of Examples 1-24 and 26-154, wherein the polymer loosely woven layer has fibers with an average diameter of 5 to 30 µ and a standard deviation of less than 5 µ. 26. The filter media package as described in any one of Examples 1-25 and 27-154, wherein the polymer sparse cloth layer has fibers with an average diameter of 10 to 20 and a standard deviation of less than 3 µm. 27. The filter media package as described in any one of Examples 1-26 and 28-154, wherein the polymer sparse cloth layer has fibers with an average diameter of 12 to 18 and a standard deviation of less than 2 µm. 28. The filter media package as described in any one of Examples 1-27 and 29-154, wherein the polymer sparse cloth layer has fibers with a standard deviation of less than 2 µ. 29. The filter media package as described in any one of Examples 1-28 and 30-154, wherein the polymer loosely woven layer has fibers with a distribution uniformity of -1.0 to -0.25 as measured by the following formula: . 30. The filter media package as described in any one of Examples 1-29 and 31-154, wherein the polymer loosely woven layer has fibers with a distribution uniformity of -1 to -0.5 as measured by the following formula: . 31. The filter media package as described in any one of Examples 1-30 and 32-154, wherein the polymer loosely woven layer has fibers with a distribution uniformity greater than -1.5 as measured by the following formula: . 32. The filter media package as described in any one of Examples 1-31 and 33-154, wherein the polymer loosely woven layer has fibers with a distribution uniformity greater than -2.0 as measured by the following formula: . 33. The filter media package as described in any one of Examples 1-32 and 34-154, wherein the polymer loosely woven layer has fibers with a distribution uniformity greater than -3.0 as measured by the following formula: . 34. The filter media package as described in any one of Examples 1-33 and 35-154, wherein the polymer sparse cloth layer has fibers with a contact point uniformity of less than 3.0. 35. The filter media package as described in any one of Examples 1-34 and 36-154, wherein the polymer sparse cloth layer has fibers with a contact point uniformity of less than 2.0. 36. The filter media package as described in any one of Examples 1-35 and 37-154, wherein the polymer sparse cloth layer has fibers with a contact point uniformity of less than 1.5. 37. The filter media package as described in any one of Examples 1-36 and 38-154, wherein the polymer sparse cloth layer has fibers with a contact point uniformity of less than 1.0. 38. The filter media package as described in any one of Examples 1-37 and 39-154, wherein the polymer loosely woven fabric layer has fibers with a contact point uniformity of 0.5 to 2.5. 39. The filter media package as described in any one of Examples 1-38 and 40-154, wherein the polymer loosely woven layer has fibers with a contact point uniformity of 1.0 to 2.0. 40. The filter media package as described in any one of Examples 1-39 and 41-154, wherein the multilayer media has an air permeability of 2.0 to 3.0 cubic feet per minute (CFM). 41. The filter media package as described in any one of Examples 1-40 and 42-154, wherein the multilayer media has an air permeability of 1.5 to 4.0 cubic feet per minute (CFM). 42. The filter media package as described in any one of Examples 1-41 and 43-154, wherein the multilayer media has an air permeability of 1.0 to 5.0 cubic feet per minute (CFM). 43. The filter media package as described in any one of Examples 1-42 and 44-154, wherein the multilayer media has an air permeability of 0.5 to 6.0 cubic feet per minute (CFM). 44. The filter media package as described in any one of Examples 1-43 and 45-154, wherein the multilayer media has an air permeability greater than 2.0 cubic feet per minute (CFM). 45. The filter media package as described in any one of Examples 1-44 and 46-154, wherein the multilayer media has an air permeability of greater than 2.5 cubic feet per minute (CFM). 46. ​​The filter media package as described in any one of Examples 1-45 and 47-154, wherein the multilayer media has an air permeability greater than 3.0 cubic feet per minute (CFM). 47. The filter media package as described in any one of Examples 1-46 and 48-154, wherein the multilayer media has an air permeability greater than 4.0 cubic feet per minute (CFM). 48. The filter media package as described in any one of Examples 1-47 and 49-154, wherein the multilayer media has an air permeability greater than 5.0 cubic feet per minute (CFM). 49. The filter media pack as described in any one of Examples 1-48 and 50-154, wherein the filter pack has an efficiency of 99.97% for 3-micron particles when the flow rate through the media pack is 1200 cfm. 50. The filter media pack as described in any one of Examples 1-49 and 51-154, wherein the filter pack has an efficiency of 99.97% for 3-micron particles when the flow rate through the media pack is 800 cfm. 51. The filter media pack as described in any one of Examples 1-50 and 52-154, wherein the filter pack has an efficiency of 99.97% for 3-micron particles when the flow rate through the media pack is 1600 cfm. 52. The filter media pack as described in any one of Examples 1-51 and 53-154, wherein the filter pack has an efficiency of 99.97% for 3-micron particles when the flow rate through the media pack is 2400 cfm. 53. The filter media pack as described in any one of Examples 1-52 and 54-154, wherein the filter pack has an efficiency of 99.97% for 3-micron particles when the flow rate through the media pack is 3000 cfm. 54. The filter media pack as described in any one of Examples 1-53 and 55-154, wherein the filter pack has an efficiency of 99.97% for 3-micron particles at a surface velocity of 5 to 25 feet per minute. 55. The filter media pack as described in any one of Examples 1-54 and 56-154, wherein the filter pack has an efficiency of 99.97% for 3-micron particles at a surface velocity of 5 feet per minute. 56. The filter media pack as described in any one of Examples 1-55 and 57-154, wherein the filter pack has an efficiency of 99.97% for 3-micron particles at a surface velocity of 10 feet per minute. 57. The filter media pack as described in any one of Examples 1-56 and 58-154, wherein the filter pack has an efficiency of 99.97% for 3-micron particles at a surface velocity of 15 feet per minute. 58. The filter media pack as described in any one of Examples 1-57 and 59-154, wherein the filter pack has an efficiency of 99.97% for 3-micron particles at a surface velocity of 20 feet per minute. 59. The filter media pack as described in any one of Examples 1-58 and 60-154, wherein the filter pack has an efficiency of 99.97% for 3-micron particles at a surface velocity of 25 feet per minute. 60. The filter media pack as described in any one of Examples 1-59 and 61-154, wherein the filter pack has an efficiency of 99.97% for 3-micron particles at a surface velocity of 30 feet per minute. 61. The filter media package as described in any one of Examples 1-60 and 62-154, wherein the multilayer media has a thickness of 6 to 9 mils. 62. The filter media package as described in any one of Examples 1-61 and 63-154, wherein the multilayer media has a thickness of 5 to 10 mils. 63. The filter media package as described in any one of Examples 1-62 and 64-154, wherein the multilayer media has a thickness of 4 to 11 mils. 64. The filter media package as described in any one of Examples 1-63 and 65-154, wherein the multilayer media has a thickness of 3 to 15 mils. 65. The filter media package as described in any one of Examples 1-64 and 66-154, wherein the multilayer media has a thickness of less than 22 mils. 66. The filter media package as described in any one of Examples 1-65 and 67-154, wherein the multilayer media has a thickness of less than 20 mils. 67. The filter media package as described in any one of Examples 1-66 and 68-154, wherein the multilayer media has a thickness of less than 15 mils. 68. The filter media package as described in any one of Examples 1-67 and 69-154, wherein the multilayer media has a thickness of less than 12 mils. 69. The filter media package as described in any one of Examples 1-68 and 70-154, wherein the multilayer media has a thickness of less than 9 mils. 70. The filter media package as described in any one of Examples 1-69 and 71-154, wherein the multilayer media has a thickness of less than 7 mils. 71. The filter media package as described in any one of Examples 1-70 and 72-154, wherein the multilayer media has a thickness of less than 6 mils. 72. The filter media package as described in any one of Examples 1-71 and 73-154, wherein the multilayer media has a thickness of less than 5 mils. 73. The filter media package as described in any one of Examples 1-72 and 74-154, wherein the multilayer media has a foaming point of 6 to 10 psi. 74. The filter media package as described in any one of Examples 1-73 and 75-154, wherein the multilayer media has a foaming point of 5 to 11 psi. 75. The filter media package as described in any one of Examples 1-74 and 76-154, wherein the multilayer media has a foaming point of 4 to 12 psi. 76. The filter media package as described in any one of Examples 1-75 and 77-154, wherein the PTFE comprises expanded PTFE (ePTFE). 77. The filter media package as described in any one of Examples 1-76 and 78-154, wherein the PTFE has an average pore size of 1.0 to 5.0 micrometers. 78. The filter media package as described in any one of Examples 1-77 and 79-154, wherein the polymer sparse cloth comprises spunbond fibers. 79. The filter media package as described in any one of Examples 1-78 and 80-154, wherein the spunbond fiber comprises polyester fiber. 80. The filter media package as described in any one of Examples 1-79 and 81-154, wherein the fibers are substantially uniformly distributed. 81. The filter media package as described in any one of Examples 1-80 and 82-154, wherein the polymer loosely woven fabric layer has a basis weight of 0.5 to 1.0 ounces / square yard. 82. The filter media package as described in any one of Examples 1-81 and 83-154, wherein the polymer loosely woven fabric layer has a basis weight of 0.6 to 0.9 ounces / square yard. 83. The filter media package as described in any one of Examples 1-82 and 84-154, wherein the polymer loosely woven fabric has a basis weight of greater than 0.5 ounces / square yard. 84. The filter media package as described in any one of Examples 1-83 and 85-154, wherein the polymer loosely woven fabric has a basis weight of less than 1.5 ounces / square yard. 85. The filter media package as described in any one of Examples 1-84 and 86-154, wherein the polymer loosely woven fabric has a basis weight of less than 2.0 ounces / square yard. 86. The filter media package as described in any one of Examples 1-85 and 87-154, wherein the polymer loosely woven layer has a thickness of 6 mils. 87. The filter media package as described in any one of Examples 1-86 and 88-154, wherein the polymer loosely woven layer has a thickness of 4 to 8 mils. 88. The filter media package as described in any one of Examples 1-87 and 89-154, wherein the polymer loosely woven layer has a thickness of 3 to 10 mils. 89. The filter media package as described in any one of Examples 1-88 and 90-154, wherein the polymer loosely woven layer has a thickness of less than 12 mils. 90. The filter media package as described in any one of Examples 1-89 and 91-154, wherein the polymer sparse cloth layer has a thickness of less than 14 mils. 91. The filter media package as described in any one of Examples 1-90 and 92-154, wherein the polymer loosely woven layer has a thickness of less than 16 mils. 92. The filter media package as described in any one of Examples 1-91 and 93-154, wherein the loosely woven polymer fabric has a density of 800 to 900 cfm / ft in 0.5 inches of water. 2 Fraser air permeability. 93. The filter media package as described in any one of Examples 1-92 and 94-154, wherein the loosely woven polymer fabric has a density of 700 to 1,000 cfm / ft in 0.5 inches of water. 2 Fraser air permeability. 94. The filter media package as described in any one of Examples 1-93 and 95-154, wherein the loosely woven polymer fabric has a density of 600 to 1,100 cfm / ft in 0.5 inches of water. 2 Fraser air permeability. 95. The filter media package as described in any one of Examples 1-94 and 96-154, wherein the loosely woven polymer fabric has a density of 550 to 1,050 cfm / ft in 0.5 inches of water. 2 Fraser air permeability. 96. The filter media package as described in any one of Examples 1-95 and 97-154, wherein the loosely woven polymer fabric has a density of 500 to 1,500 cfm / ft in 0.5 inches of water. 2 Fraser air permeability. 97. The filter media package as described in any one of Examples 1-96 and 98-154, wherein the loosely woven polymer fabric has a density greater than 500 cfm / ft in 0.5 inches of water. 2 Fraser air permeability. 98. The filter media package as described in any one of Examples 1-97 and 99-154, wherein the loosely woven polymer fabric has a density greater than 700 cfm / ft in 0.5 inches of water. 2 Fraser air permeability. 99. The filter media package as described in any one of Examples 1-98 and 100-154, wherein the polymer sparse cloth layer has a Fraser air permeability of greater than 900 cfm / ft2 at 0.5 inches of water. 100. The filter media package as described in any one of Examples 1-99 and 101-154, wherein the fibers are substantially uniformly distributed such that the standard deviation of the fiber spacing is from 0.5 to 1.0. 101. The filter media package as described in any one of Examples 1-100 and 102-154, wherein the fibers are substantially uniformly distributed such that the standard deviation of the fiber spacing is from 0.6 to 0.9. 102. The filter media package as described in any one of Examples 1-101 and 103-154, wherein the fibers are substantially uniformly distributed such that the standard deviation of the fiber spacing is from 0.7 to 0.8. 103. The filter media package as described in any one of Examples 1-102 and 104-154, wherein the fibers are substantially uniformly distributed such that the standard deviation of the fiber spacing is from 0.25 to 1.0. 104. The filter media package as described in any one of Examples 1-103 and 105-154, wherein the filter media package further comprises an additional layer between the PTFE layer and the polymer sparse cloth layer. 105. The filter media package as described in any one of Examples 1-104 and 106-154, wherein the additional layer comprises polypropylene or polyethylene. 106. The filter media package as described in any one of Examples 1-105 and 107-154, wherein the polymer loose cloth layer further comprises cellulose. 107. The filter media package as described in any one of Examples 1-106 and 108-154, wherein the PTFE has a thickness of 6 to 10 mils. 108. The filter media package as described in any one of Examples 1-107 and 109-154, wherein the PTFE has a thickness of 4 to 12 mils. 109. The filter media package as described in any one of Examples 1-108 and 110-154, wherein the PTFE has a thickness of 7 to 9 mils. 110. The filter media package as described in any one of Examples 1-109 and 111-154, wherein the PTFE has a thickness of 2 to 14 mils. 111. The filter media package as described in any one of Examples 1-110 and 112-154, wherein the PTFE has a thickness of 5 to 10 mils. 112. The filter media package as described in any one of Examples 1-111 and 113-154, wherein the PTFE has a thickness of more than 4 mils. 113. The filter media package as described in any one of Examples 1-112 and 114-154, wherein the PTFE has a thickness of more than 5 mils. 114. The filter media package as described in any one of Examples 1-113 and 115-154, wherein the PTFE has a thickness of more than 6 mils. 115. The filter media package as described in any one of Examples 1-114 and 116-154, wherein the PTFE has a thickness of more than 7 mils. 116. The filter media package as described in any one of Examples 1-115 and 117-154, wherein the PTFE has a thickness of less than 9 mils. 117. The filter media package as described in any one of Examples 1-116 and 118-154, wherein the PTFE has a thickness of less than 10 mils. 118. The filter media package as described in any one of Examples 1-117 and 119-154, wherein the PTFE has a thickness of less than 12 mils. 119. The filter media package as described in any one of Examples 1-118 and 120-154, wherein the PTFE has a thickness of less than 15 mils. 120. The filter media package as described in any one of Examples 1-119 and 121-154, wherein the PTFE has a thickness of less than 20 mils. 121. The filter media package as described in any one of Examples 1-120 and 122-154, wherein the PTFE has a concentration of 200 to 300 cfm / ft. 2 Air permeability. 122. The filter media package as described in any one of Examples 1-121 and 123-154, wherein the PTFE has a content of 150 to 350 cfm / ft. 2 Air permeability. 123. The filter media package as described in any one of Examples 1-122 and 124-154, wherein the PTFE has a concentration of 100 to 400 cfm / ft. 2 Air permeability. 124. The filter media package as described in any one of Examples 1-123 and 125-154, wherein the PTFE has a concentration of 500 to 500 cfm / ft. 2 Air permeability. 125. The filter media package as described in any one of Examples 1-124 and 126-154, wherein the PTFE has a concentration greater than 100 cfm / ft. 2 Air permeability. 126. The filter media package as described in any one of Examples 1-125 and 127-154, wherein the PTFE has a density greater than 125 cfm / ft. 2 Air permeability. 127. The filter media package as described in any one of Examples 1-126 and 128-154, wherein the PTFE has a density greater than 150 cfm / ft. 2 Air permeability. 128. The filter media package as described in any one of Examples 1-127 and 129-154, wherein the PTFE has a concentration greater than 200 cfm / ft. 2 Air permeability. 129. The filter media package as described in any one of Examples 1-128 and 130-154, wherein the PTFE has a density greater than 225 cfm / ft. 2 Air permeability. 130. The filter media package as described in any one of Examples 1-129 and 131-154, wherein the PTFE has a density of less than 275 cfm / ft. 2 Air permeability. 131. The filter media package as described in any one of Examples 1-130 and 132-154, wherein the PTFE has a content of less than 300 cfm / ft. 2 Air permeability. 132. The filter media package as described in any one of Examples 1-131 and 133-154, wherein the PTFE has a content of less than 350 cfm / ft. 2 Air permeability. 133. The filter media package as described in any one of Examples 1-132 and 134-154, wherein the PTFE has a content of less than 400 cfm / ft. 2 Air permeability. 134. The filter media package as described in any one of Examples 1-133 and 135-154, wherein the PTFE has a content of less than 500 cfm / ft. 2 Air permeability. 135. The filter media package as described in any one of Examples 1-134 and 136-154, wherein the PTFE has a content of less than 1000 cfm / ft. 2 Air permeability. 136. The filter media package as described in any one of Examples 1-135 and 137-154, wherein the PTFE has a mullion burst strength of 25 to 75 psi. 137. The filter media package as described in any one of Examples 1-136 and 138-154, wherein the PTFE has a mullion burst strength of 10 to 90 psi. 138. The filter media package as described in any one of Examples 1-137 and 139-154, wherein the PTFE has a mullion burst strength of 10 to 100 psi. 139. The filter media package as described in any one of Examples 1-138 and 140-154, wherein the PTFE has a mullion burst strength of less than 125 psi. 140. The filter media package as described in any one of Examples 1-139 and 141-154, wherein the PTFE has a mullion burst strength of less than 150 psi. 141. The filter media package as described in any one of Examples 1-140 and 142-154, wherein the PTFE has a mullion burst strength of less than 200 psi. 142. The filter media package as described in any one of Examples 1-141 and 143-154, wherein the PTFE has a strip tensile strength (MD / CD, kg / 5 cm) of 60 / 48. 143. The filter media package as described in any one of Examples 1-142 and 144-154, wherein the PTFE has a strip tensile strength (MD / CD, kg / 5 cm) of 40 to 80 / 40 to 60. 144. The filter media package as described in any one of Examples 1-143 and 145-154, wherein the PTFE has a strip tensile strength (MD / CD, kg / 5 cm) of 30 to 90 / 30 to 70. 145. The filter media package as described in any one of Examples 1-144 and 146-154, wherein the PTFE has a strip tensile strength (MD / CD, kg / 5 cm) of 20 to 100 / 20 to 80. 146. The filter media package as described in any one of Examples 1-145 and 147-154, wherein the PTFE has a basis weight of 1.0 to 3.0 ounces / square yard. 147. The filter media package as described in any one of Examples 1-146 and 148-154, wherein the PTFE has a basis weight of 1.5 to 2.5 ounces per square yard. 148. The filter media package as described in any one of Examples 1-147 and 149-154, wherein the PTFE has a basis weight of 0.5 to 3.0 ounces / square yard. 149. The filter media package as described in any one of Examples 1-148 and 150-154, wherein the PTFE has a basis weight of greater than 0.5 ounces / square yard. 150. The filter media package as described in any one of Examples 1-149 and 151-154, wherein the PTFE has a basis weight greater than 1.0 ounce / square yard. 151. The filter media package as described in any one of Examples 1-150 and 152-154, wherein the PTFE has a basis weight of greater than 1.5 ounces / square yard. 152. The filter media package as described in any one of Examples 1-151 and 153-154, wherein the PTFE has a basis weight of less than 3.0 ounces / square yard. 153. The filter media package as described in any one of Examples 1-152 and 154, wherein the PTFE has a basis weight of less than 4.0 ounces / square yard. 154. The filter media package as described in any one of Examples 1-153, wherein the PTFE has a basis weight of less than 5.0 ounces / square yard. It should be noted that, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include the plural objects mentioned, unless the context clearly indicates otherwise. It should also be noted that, unless the context clearly indicates otherwise, the term “or” generally includes the meaning of “and / or.” It should also be noted that, as used in this specification and the appended claims, the phrase “configured as” describes a system, apparatus or other structure constructed or configured to perform a particular task or employ a particular configuration. The phrase “configured as” may be used interchangeably with other similar phrases, such as “arranged and configured as,” “constructed and arranged as,” “constructed as,” “manufactured and arranged as,” etc. All publications and patent applications in this specification demonstrate the skill of one ordinary person in the art to which this invention pertains. All publications and patent applications are incorporated herein by reference to the extent that each individual publication or patent application is expressly and individually indicated by reference. As used herein, references to a range of values ​​for an endpoint should include all values ​​included within that range (e.g., 2 to 8 includes 2.1, 2.8, 5.3, 7, etc.). The headings used herein are provided to align with the recommendations under 37 CFR 1.77 or otherwise provide organizational clues. These headings should not be construed as limiting or characterizing any invention set forth in any claim that may be published in this disclosure. As an example, although the heading refers to the “technical field,” such claims should not be limited by the language chosen under this heading to describe the so-called technical field. Furthermore, the description of the technology in the “Background Art” section does not acknowledge that the technology is prior art to any invention in this disclosure. Nor should the term “Summary of the Invention” be construed as characterizing the invention set forth in any published claim. The embodiments described herein are not intended to be exhaustive or to limit the invention to the exact forms disclosed in the following detailed description. Rather, the embodiments were chosen and described so that others skilled in the art can understand and comprehend the principles and practices. Thus, aspects have been described with reference to various specific and preferred embodiments and techniques. However, it should be understood that many variations and modifications can be made while remaining within the spirit and scope of this document.

Claims

1. A filter media package, comprising: (a) A plurality of single-sided media layers, wherein the single-sided media layer comprises a grooved sheet, a surface sheet, and a plurality of grooves extending between the grooved sheet and the surface sheet, and the plurality of grooves having a groove length extending from a first side of the filter media pack to a second side of the filter media pack. (b) A first portion of the plurality of grooves is closed to unfiltered fluid flowing into the first portion of the plurality of grooves, and a second portion of the plurality of grooves is closed to unfiltered fluid flowing out of the second portion of the plurality of grooves, such that fluid entering one of the first or second surfaces of the medium package and exiting the other of the first or second surfaces of the medium package passes through the medium to provide filtration of the fluid; wherein, The grooved sheet and surface sheet are formed of a multilayer medium comprising a polytetrafluoroethylene (PTFE) layer supported by a loosely woven polymer fabric layer; and The loosely woven polymer layer has an external maximum peak height S of less than 5 µm, measured between the highest peak and the average plane. P .

2. The filter media package as described in claim 1, wherein, The polymer sparse fabric layer has an external root-mean-square height S of less than 40 µm according to the following formula. q : Where A is the area of ​​the measured polymer sparse fabric layer, x and y are the coordinates in the plane formed by the polymer sparse fabric layer, and z is the height perpendicular to the plane formed by the polymer sparse fabric layer.

3. The filter media package as described in claim 1, wherein, The polymer sparse fabric layer has an external root-mean-square height S of less than 20 µm according to the following formula. q : Where A is the area of ​​the measured polymer sparse fabric layer, x and y are the coordinates in the plane formed by the polymer sparse fabric layer, and z is the height perpendicular to the plane formed by the polymer sparse fabric layer.

4. The filter media package as described in claim 1, wherein, The polymer sparse fabric layer has an external arithmetic mean height S of less than 60µm according to the following formula. a : Where A is the area of ​​the measured polymer sparse fabric layer, x and y are the coordinates in the plane formed by the polymer sparse fabric layer, and z is the height perpendicular to the plane formed by the polymer sparse fabric layer.

5. The filter media package as described in claim 1, wherein, The polymer sparse fabric layer has an external arithmetic mean height S of less than 30 µm. a Where A is the area of ​​the measured polymer sparse fabric layer, x and y are the coordinates in the plane formed by the polymer sparse fabric layer, and z is the height perpendicular to the plane formed by the polymer sparse fabric layer.

6. The filter media package as described in claim 1, wherein, The polymer sparse fabric layer has an external arithmetic mean height S of less than 20 µm. a Where A is the area of ​​the measured polymer sparse fabric layer, x and y are the coordinates in the plane formed by the polymer sparse fabric layer, and z is the height perpendicular to the plane formed by the polymer sparse fabric layer.

7. The filter media package as described in claim 1, wherein, The polymer sparse fabric layer has fibers with an average diameter of 10 to 20 µm and a standard deviation of less than 3 µm.

8. The filter media package as described in claim 1, wherein, The polymer sparse fabric layer has fibers with an average diameter of 12 to 18 µm and a standard deviation of less than 2 µm.

9. The filter media package as described in claim 1, wherein, The loosely woven polymer layer has fibers, the uniformity of fiber distribution being measured by the variance from the average density as ranging from −1 to −0.5, the uniformity being determined using a dispersion index calculated according to the following formula: in, is the variance, and µ is the mean.

10. The filter media package as claimed in claim 1, wherein, The multilayer medium has an air permeability of greater than 4.0 cubic feet per minute (CFM).

11. The filter media package as claimed in claim 1, wherein, The filter media pack is 99.97% efficient at removing 3-micron particles at a surface velocity of 10 feet per minute.

12. The filter media package as claimed in claim 1, wherein, The multilayer medium has a thickness of less than 20 mils.

13. The filter media package as claimed in claim 1, wherein, The polymer loose fabric contains spunbond fibers.

14. The filter media package as claimed in claim 13, wherein, The spunbond fiber includes polyester fiber.

15. The filter media package as claimed in claim 1, wherein, The polymer sparse fabric layer has a basis weight of less than 2.0 ounces per square yard.

16. The filter media package as claimed in claim 1, wherein, The loosely woven polymer fabric layer has a strength greater than 900 cfm / ft at 0.5 inches of water. 2 Fraser air permeability.

17. The filter media package as claimed in claim 1, wherein, The PTFE has a basis weight of 1.5 to 2.5 ounces per square yard.

18. The filter media package as claimed in claim 1, wherein, The PTFE has a basis weight of less than 3.0 ounces per square yard.

19. A filter media package, comprising: (a) A plurality of single-sided media layers, wherein the single-sided media layer comprises a grooved sheet, a surface sheet and a plurality of grooves extending between the grooved sheet and the surface sheet, and the plurality of grooves having a groove length extending from a first side of the filter media pack to a second side of the filter media pack. (b) The first portion of the plurality of grooves is closed to unfiltered fluid flowing into the first portion of the plurality of grooves, and the second portion of the plurality of grooves is closed to unfiltered fluid flowing out of the second portion of the plurality of grooves, such that fluid entering one of the first or second surfaces of the medium package and exiting the other of the first or second surfaces of the medium package passes through the medium to provide filtration of the fluid; wherein, The grooved sheet and surface sheet are formed of a multilayer medium comprising a polytetrafluoroethylene (PTFE) layer supported by a loosely woven polymer fabric layer; and The polymer sparse fabric layer has an external root-mean-square height S of less than 40 µm according to the following formula. q : Where A is the area of ​​the measured polymer sparse fabric layer, x and y are the coordinates in the plane formed by the polymer sparse fabric layer, and z is the height perpendicular to the plane formed by the polymer sparse fabric layer.

20. A filter media package, comprising: (a) A plurality of single-sided media layers, wherein the single-sided media layer comprises a grooved sheet, a surface sheet and a plurality of grooves extending between the grooved sheet and the surface sheet, and the plurality of grooves having a groove length extending from a first side of the filter media pack to a second side of the filter media pack. (b) The first portion of the plurality of grooves is closed to unfiltered fluid flowing into the first portion of the plurality of grooves, and the second portion of the plurality of grooves is closed to unfiltered fluid flowing out of the second portion of the plurality of grooves, such that fluid entering one of the first or second surfaces of the medium package and exiting the other of the first or second surfaces of the medium package passes through the medium to provide filtration of the fluid; wherein, The grooved sheet and the surface sheet are formed of a multilayer medium including a polytetrafluoroethylene (PTFE) layer supported by a polymer sparse cloth layer; The polymer sparse fabric layer has fibers with a distribution uniformity of -1 to -0.5 as measured by the following formula: in, is the variance, and µ is the mean.

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