Combined Media

Abstract

An embodiment relates to a filter material for coalescing a dispersed phase in a continuous phase. The filter material has binder fibers and irregular rayon fibers distributed among the binder fibers. The filter material does not include a non-fibrous resin. An embodiment relates to a filter assembly. The filter assembly has a particle filtration layer, a coalescing layer downstream of the particle filtration layer, and a growth medium downstream of the coalescing layer. The coalescing layer is bonded to the particle filtration layer. The growth medium has irregular rayon fibers and binder fibers distributed among the irregular rayon fibers. The growth medium does not include a non-fibrous resin.

Description

[Technical field]

[0001]

[0001] Claiming priority This application claims the benefit of U.S. Provisional Patent Application No. 63 / 273,639, filed October 29, 2021, which is incorporated by reference in its entirety.

[0002] TECHNICAL FIELD TO WHICH THEINVENTION BELONGS The technology disclosed herein relates generally to coalescing media. More specifically, the technology disclosed herein relates to a coalescing media for liquid hydrocarbon streams. Summary of the Invention

[0002]

[0003] The technology disclosed herein generally relates to coalesced filter materials. Certain embodiments have improved coalescing performance in liquid hydrocarbon streams compared to other types of coalescing media. Certain embodiments of the filter materials are relatively strong and can be more easily and advantageously subjected to automated manufacturing processes for forming into filter assemblies. In certain embodiments, the coalesced filter materials of the present technology advantageously have a high exposed surface area of ​​rayon fibers in the filter material, which can reduce the exposed surface area of ​​non-rayon components to improve coalescing performance. In certain embodiments, the coalesced filter material is a wet rayon filter material.

[0003]

[0004] Certain embodiments of the technology disclosed herein relate to a filter material. The filter material includes binder fibers and random rayon fibers distributed among the binder fibers. The filter material does not include a non-fibrous resin.

[0005] In one embodiment, the filter material has an air permeability of 100 to 500 ft at 125 Pa. 3 / min·ft 2Additionally or alternatively, the filter material further comprises fibrillated rayon fibers. Additionally or alternatively, the filter material has a thickness of at least 0.25 mm. Additionally or alternatively, the filter material is up to 70% by weight polyester fibers. Additionally or alternatively, the filter material is 30% to 75% by weight rayon fibers. Additionally or alternatively, the filter material is free of a support layer. Additionally or alternatively, the filter material is free of glass. Additionally or alternatively, the filter material comprises natural cellulose fibers. Additionally or alternatively, the irregular rayon fibers are multilobal rayon fibers. Additionally or alternatively, the irregular rayon fibers have a linear mass density of 1 den to 7 den. Additionally or alternatively, the filter material comprises a plurality of low resistance flow paths through said filter material.

[0004]

[0006] Some embodiments relate to a filter assembly including a particle filtration layer and a coalescing layer downstream of the particle filtration layer, the coalescing layer being bonded to the particle filtration layer, and a growth medium downstream of the coalescing layer, the growth medium including irregular rayon fibers and binder fibers distributed among the irregular rayon fibers, the growth medium being free of non-fibrous resin.

[0007] In one embodiment, the particle filtration layer, the coalescing layer, and the growth medium are pleated and collectively define a tubular structure. Additionally or alternatively, the particle filtration layer and the coalescing layer are pleated and collectively define a tubular structure with a central opening, and the growth medium forms a non-pleated tube within the central opening. Additionally or alternatively, the particle filtration layer and the coalescing layer are pleated and collectively define a tubular structure with a central opening, and the growth medium is pleated and defines a tubular structure, and wherein a radial gap is defined between the growth medium and the coalescing layer. Additionally or alternatively, a porous barrier is downstream of the growth medium. Additionally or alternatively, the porous barrier forms a tubular structure. Additionally or alternatively, the growth medium has an air permeability of 100 to 500 ft@125 Pa. 3 / min·ft 2Additionally or alternatively, the growth medium comprises fibrillated rayon fibers. Additionally or alternatively, the growth medium has a thickness of at least 0.4 mm.

[0008] Additionally or alternatively, the growing medium is up to 70% polyester fiber by weight. Additionally or alternatively, the growing medium is 40% to 75% rayon fiber by weight. Additionally or alternatively, the growing medium is free of a support layer. Additionally or alternatively, the growing medium is free of glass. Additionally or alternatively, the growing medium comprises natural cellulose fibers. Additionally or alternatively, the irregular rayon fibers are multilobal rayon fibers. Additionally or alternatively, the irregular rayon fibers have a linear mass density of 1 den to 7 den. Additionally or alternatively, the growing medium defines a plurality of low resistance flow paths through the growing medium.

[0005]

[0009] The above summary is not intended to describe each embodiment or every implementation. Rather, a more complete understanding of the example embodiments will become apparent and appreciated by reference to the following detailed description of example embodiments and claims, when taken in conjunction with the accompanying drawing figures.

[0010] The present technology may be more fully understood and appreciated in consideration of the following detailed description of various embodiments in conjunction with the accompanying drawings, in which:

[0006]

[0019] The figures are drawn primarily for clarity and, as a result, are not necessarily drawn to scale. Additionally, various structures / components, including but not limited to fasteners, electrical components (wiring, cables, etc.), etc., may be shown diagrammatically or removed from some or all of the figures to better illustrate aspects of the illustrated embodiment or where the inclusion of such structures / components is not necessary for an understanding of the various exemplary embodiments described herein. However, the absence of showing / description of such structures / components in a particular figure should not be construed as limiting the scope of the various embodiments in any way. [Brief description of the drawings]

[0007] [Figure 1] 1 is a SEM (scanning electron microscope) image depicting fibers of a filtration media consistent with the technology disclosed herein. [Diagram 2]

[0012] Figure 2A is a first cross-sectional view of a first exemplary filter assembly consistent with an embodiment.

[0013] Figure 2B is a second cross-sectional view of the first exemplary filter assembly consistent with an embodiment. [Diagram 3]

[0014] Figure 3A is a first cross-sectional view of a second exemplary filter assembly consistent with certain embodiments.

[0015] Figure 3B is a second cross-sectional view of a second exemplary filter assembly consistent with certain embodiments. [Figure 4]

[0016] Figure 4A is a first cross-sectional view of a third exemplary filter assembly consistent with an embodiment.

[0017] Figure 4B is a second cross-sectional view of the third exemplary filter assembly consistent with an embodiment. [Diagram 5] FIG. 5 is a graph showing the test results. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008]

[0020] The filter materials disclosed herein are configured to coalesce a dispersed phase (such as entrained air or water) from a continuous phase (such as a liquid hydrocarbon). The filter materials disclosed herein are generally configured for liquid hydrocarbon filtration systems. In some embodiments, the filter materials are configured to coalesce water from a liquid hydrocarbon stream, such as a fuel stream. In some embodiments, the filter materials are configured to degas in a liquid hydrocarbon stream, such as an oil stream. The filter materials disclosed herein are growth media, meaning that the filter materials are configured to grow droplets or pockets of the dispersed phase. Such growth allows for easy removal of the dispersed phase from the continuous phase.

[0021] In various embodiments, the filter material is configured to be disposed downstream of the liquid hydrocarbon filter assembly, which is configured to remove contaminants from the liquid hydrocarbons. The contaminants may include particles, entrained water, and entrained air. In various embodiments, the filter material is configured to be disposed downstream of the liquid hydrocarbon filter assembly that includes a coalescing media.

[0009] definition

[0022] As used herein, unless otherwise indicated, pore sizes (e.g., P10 and P90) and pore size ratios (e.g., P90 / P10) are determined using capillary flow porometry. Capillary flow porometry may be performed using a continuous pressure scan mode. It may be useful to use silicone oil as the wetting fluid, which has a surface tension of 20.1 dynes / cm and a wetting contact angle of 0. The sample may be first dry tested at low to high pressure and then wet tested again at low to high pressure. Testing is performed at ambient temperature conditions (e.g., 20°C to 25°C). 256 data points may be collected over the range of pressure scans for both the dry and wet curves. Typically, tortuosity and / or shape factors are not used (i.e., factors equal to 1 may be used for comparison with other test methods that use adjustment factors).

[0010]

[0023] As used herein, the value P(x%) is the calculated pore size when the wet curve is equal to (100-x)% of the dry curve, as determined using the methodology described herein. Although a calculated value, it can be understood as representing the point at which x% of the total flow through the layer passes through pores of that size or smaller. For example, P10 represents the pore diameter at which 10% of the fluid flows through pores of that diameter or smaller, and P95 represents the pore diameter at which 95% of the fluid flows through pores of that diameter or smaller.

[0011]

[0024] "Binder fiber" as used herein refers to a material structured as filaments or threads with at least one thermoplastic binder polymer component configured to bind the fibers in the filter material.

[0025] "Fibrillated" fibers are defined herein as fibers that have been processed to form a branched structure of smaller fibrils.

[0026] "Irregular" as used herein to characterize fibers is used to mean that the cross section of each fiber along its length (perpendicular to the length of the fiber) has a portion of the fiber circumference that is concave.

[0027] "Lobular" fibers are used herein to mean that in a cross section perpendicular to the length of the fiber, the fiber has projections (or lobes) that extend outwardly from other portions of the fiber.

[0028] "Machine direction tensile strength" is the peak strength of a sample material measured on a tensile tester according to TAPPI standard T494os-13. A 25.4 mm by 152.4 mm sample of filter material is cut with the machine direction running along the elongated direction of the sample. The tensile tester is set to move 50.8 mm per minute. Tensile strength is disclosed in N / cm, which is the unit of force per unit width.

[0029] The "burst strength" of a sample material is measured according to TAPPI T403(2015) and ASTM D774(2007) using a TMI 13-60-00 EC 35 burst tester from Testing Machines, Inc., New Castle, Delaware.

[0030] "Gurley Stiffness" measures the force required to bend a sheet of material. Gurley Stiffness is calculated using a Gurley Stiffness Tester that meets industry standards TAPPI#T543 OM-16(2016) and ASTM D6125-97(2007).

[0012]

[0031] "Natural cellulose fibers" is used herein to refer to cellulose fibers that maintain their original structure from the time of harvest. Natural cellulose fibers are non-regenerated fibers, while "regenerated fibers" are fibers that have been chemically and / or physically treated to break down the original fiber structure and then reconstituted with a new fiber structure. Examples of regenerated cellulose fibers include rayon and viscose.

[0032] "Air permeability" is the amount of air (in ft ) that will flow through a filter medium with a pressure drop of 125 Pa (about 0.5 inches of water). 3 / min·ft 2 (-min-1-ft-2). Generally, as the term is used, permeability is evaluated by the Frazier Permeability Test in accordance with ASTM D737 using a Frazier Permeability Tester available from Frazier Precision Instrument Co. Inc., Gaithersburg, Maryland, or a TexTest 3300 or TexTest 3310 available from Advanced Testing Instruments Corp (ATI), Spartanburg, So. Carolina 29301.

[0013] Filter Material Composition

[0033] The filter material disclosed herein is generally a sheet of intermixed and bonded fibers. In various embodiments, the filter material includes binder fibers and rayon fibers. In some embodiments, the filter material is limited to binder fibers and rayon fibers and no other components. In some embodiments, the filter material is limited to binder fibers, rayon fibers, and natural cellulose fibers and no other components. In an embodiment, the binder fibers are bicomponent fibers. The bicomponent fibers may be polyester bicomponent fibers. In an embodiment, the rayon fibers include irregular rayon fibers. In an embodiment, the rayon fibers include fibrillated rayon fibers. The fibers in the filter material are described in more detail below.

[0034] In various embodiments, the filter material is glass fiber-free, meaning that the glass fibers are less than 3%, less than 1%, less than 0.5%, or 0% by weight of the filter material. Such a configuration may be desirable in embodiments where the filter material is the most downstream filter medium in a filtration system and the glass fibers may negatively interact with downstream system components. In some embodiments, the filter material is a single layer of material. However, in some embodiments of the filter material, it may be desirable to stack multiple layers of the filter material in a filter assembly.

[0014]

[0035] In some embodiments, the filter material is generally free of a support layer, such as a scrim layer. A "support layer" is defined herein as a separate layer of material configured to be bonded to the filter material, where the primary function of the support layer is to provide structural integrity to the filter material, rather than a filtering (including coalescing) function. The support layer is generally characterized by a high air permeability relative to the coalescing layer. The air permeability of the support layer is generally greater than 200 ft 3 / min·ft 2 In various embodiments, the air permeability of the support layer is 400 ft 3 / min·ft 2 That is all. The air permeability of a certain support layer is 1000ft 3 / min·ft 2 The following is the result.

[0015]

[0036] In various embodiments, a sheet of filter material has a varying flow resistance through the sheet across the surface area of ​​the sheet. The sheet can define a plurality of separate relatively low resistance flow paths through the sheet, with the fiber density in the flow paths being lower than adjacent locations through the sheet. Each of the relatively low resistance flow paths generally has a length extending through the thickness of the media and a cross-sectional dimension perpendicular to the length (such as a diameter or diagonal measurement). The low resistance flow paths can be formed, at least in part, during the formation of the filter material sheet itself using certain types of fibers, which are described in more detail below. The low resistance flow paths can be quantified in terms of a pore size distribution, for example, where a large pore size distribution represents a relatively high variation in flow resistance across the media. Pore size distributions are described in more detail below.

[0037] The presence of relatively low resistance flow paths through a sheet of filter material can, in some embodiments, advantageously promote coalescence and growth of a dispersed phase (such as water or air). The flow paths, in some examples, may be formed in a pattern across at least a portion of the sheet of filter material. In some embodiments, the flow paths are generally not visible to the naked eye.

[0038] In some embodiments, the low resistance flow path is defined, at least in part, by a perforation formed through a narrow puncture or cut through the medium, such as by piercing a needle through the medium. One or more fibers can be cut or broken at the puncture location to form the puncture. Thus, one or more fiber ends can be positioned at or adjacent to the puncture location. The area of ​​the filter material that forms the low resistance flow path is generally irregular and non-uniform. In some embodiments, the area of ​​the filter material that forms the low resistance flow path is not smooth if the flow path is formed by a melting / burning operation such as laser ablation. The fiber ends and fibers that define the puncture location are those that can advantageously increase the interaction between the fiber and the fluid and define a flow path for the aggregated dispersed phase.

[0016] Filter Material Properties

[0039] The filter materials disclosed herein generally have a filter capacity of 40 g / m 2~150g / m 2 in one embodiment, 100 g / m 2 ~150g / m 2 The basis weight of the filter material may depend on the particular configuration of the material when implemented into a particular filter element. For example, if the filter material is configured to be wrapped in a coiled configuration around a core to form multiple layers around the core, the basis weight of a single layer of the filter material may range from 40 g / m 2 ~70g / m 2 while the combination of layers of filter material disposed around the core may be close to 100 g / m 2 ~150g / m 2 In embodiments where the filter material is pleated with other media layers, the filter material may have a basis weight in the range of 40 g / m 2 ~70g / m 2 A relatively low range of 100% may be desirable. A relatively low basis weight may increase the flexibility of the filter material, which may be advantageous for various filter assembly manufacturing processes including, by way of example, co-pleating or wrapping.

[0040] In various embodiments, the filter material has an air permeability of 100 ft 3 / min·ft 2 ~500ft 3 / min·ft 2 In one embodiment, the air permeability is in the range of 130 ft 3 / min·ft 2 ~300ft 3 / min·ft 2 or 130ft 3 / min·ft 2 ~200ft 3 / min·ft 2 The range is.

[0017]

[0041] The thickness of the filter material may range from 0.2 mm to 2.0 mm or from 0.5 mm to 1.8 mm, the thickness being measured at 1.5 psi (10.3 kPa). In some embodiments, the thickness of the filter material is at least 0.25 mm. In some embodiments, the thickness of the filter material is at least 0.4 mm.

[0018]

[0042] A further feature of the filter material is that it may have a relatively low toughness. As used herein, the term "toughness" is the solid fiber volume divided by the total volume of a given filter material, usually expressed as a percentage. In typical embodiments, the toughness of the particulate filter layer is less than 15%, more usually less than 12%, and more frequently less than 10%. In various embodiments, the toughness of the filter material is in the range of 5% to 9%.

[0019]

[0043] The P10 value of the filter material may range from 5.0 μm to 20.0 μm, the P10 value reflecting the pore diameter through which 10% of the fluid flows or less. The P95 value of the filter material may range from 75.0 μm to 200.0 μm, the P95 value reflecting the pore diameter through which 95% of the fluid flows or less. The P95 / P10 ratio may range from 5 to 10, with a larger P95 / P10 ratio generally reflecting a larger range of pore sizes in which relatively large pores exist. In some embodiments, the coalescence performance of filter materials with a relatively large range of pore sizes may be improved.

[0020]

[0044] In some embodiments, filter materials consistent with the technology disclosed herein are relatively tough. Such construction can advantageously simplify the manufacture of the media. Such construction can advantageously omit a support layer that can negatively interfere with the performance of the filter material. For example, in some embodiments, the filter material has a machine direction tensile strength in the range of 10.0 N / cm to 40.0 N / cm. In some examples, the machine direction tensile strength is in the range of 15 N / cm to 30 N / cm. As another example, in some embodiments, the filter material has a burst strength in the range of 150 kPa to 600 kPa. In some specific examples, the burst strength is in the range of 400 kPa to 600 kPa. As another example, in some embodiments, the filter material has a machine direction Gurley stiffness in the range of 600 mg to 2500 mg. The Gurley stiffness can be in the range of 1000 mg to 2500 mg or 1400 mg to 2300 mg in some embodiments.

[0021] Binder Fiber

[0045] Binder fibers are generally configured to provide support for other fibers in the filter material and can also add strength and compression resistance to the filter material to improve processability. In some embodiments, the binder fibers also improve processability during downstream processing, including furnish compounding, sheet or layer formation, and thickness control, drying, cutting, and forming filter elements. The filter material can be formed in part by a heating process in which a thermoplastic binder polymer at least partially melts and bonds to abutting fibers in the fiber mixture. In some embodiments, the binder fibers can include a thermosetting polymer.

[0046] As used herein, binder fibers generally have a minimum melting point greater than the intended operating environment of the resulting filter material, hi some embodiments, the melting point of all of the binder fibers in the formed filter material is at least 80°C, at least 90°C, or at least 100°C.

[0022]

[0047] The binder fibers disclosed herein may advantageously omit non-fibrous resins as binders in filter materials. Non-fibrous resins may have some drawbacks associated with some implementations of current technology. For example, non-fibrous resins may undesirably form a reducing film on the fiber surface that may hinder the performance of the fiber and reduce the functional surface area of ​​the fiber in the filter material. Non-fibrous resins may partially or completely fill the pores of the filter material, which may hinder the performance of the filter material, for example, by reducing the permeability of the filter material. Furthermore, non-fibrous resins may cause the uniformity of the filter material to be compromised as the resin migrates to certain locations in the media layer. In some embodiments, filter materials consistent with the technology disclosed herein do not include non-fibrous resins, which is used herein to mean that the filter media is less than 3% by weight, less than 1% by weight, less than 0.5% by weight, or 0% by weight of the filter material.

[0048] The use of binder fibers may advantageously omit a support layer, such as a scrim layer, of a filter material consistent with the present disclosure. In particular, the binder fibers may be configured to provide sufficient strength and stiffness to the filter material such that a support layer is not required. Filter materials without a support layer may advantageously have improved coalescence compared to filter materials with a support layer. In the latter case, the support layer may adversely affect coalescence by reducing the growth of the dispersed phase or by preventing clean release of the dispersed phase from the filter material. Furthermore, adding a support layer to a filter material adds at least a manufacturing step associated with bonding the support layer to other layers of the filter material. Thus, omitting the support layer may advantageously simplify the manufacture of the filter assembly.

[0023]

[0049] The binder fibers may generally comprise less than 70% by weight of the filter material. In some embodiments, the filter material has greater than 0% by weight binder fibers. In some embodiments, the filter material has 15%-45%, 20%-50%, or 25%-45% binding fibers. In some embodiments, the binder fibers may comprise monocomponent binder fibers, such as nylon or polyester fibers. In some other embodiments, the binder fibers may comprise bicomponent fibers, as described below.

[0024] Bicomponent Fiber

[0050] In some embodiments, the binder fiber may incorporate one or more types of bicomponent fibers. The bicomponent fiber may include any suitable bicomponent fiber or combination of bicomponent fibers. The term "bicomponent fiber" refers to a fiber having at least one thermoplastic binder polymer portion with a melting point and a second thermoplastic structural polymer portion that is different from the binder polymer portion but has a higher melting point than the binder polymer portion. The physical configuration of these fibers is usually a "side-by-side" or "sheath-core" configuration. In a side-by-side configuration, two thermoplastic polymer resins are usually extruded in a connected form in a side-by-side configuration. Other fiber configurations include lobed bicomponent fibers, where the tip of the fiber has a lobe formed from a polymer with a lower melting point than the rest of the fiber. The low melting point polymer acts as the binder and the high melting point polymer acts as the structural material. In a sheath-core configuration, the core has a higher structural fiber melting point and the sheath has a lower tie layer melting point. In some embodiments, the bicomponent fiber preferably has a sheath-core configuration.

[0025]

[0051] In some embodiments, a filter material consistent with the technology disclosed herein may have up to 70% by weight bicomponent fibers. In some embodiments, a filter material has greater than 0% bicomponent fibers. In some embodiments, a filter material has 15%-45%, 20%-50%, or 25%-45% bicomponent fibers.

[0052] The melting point of the low melting point polymer of the bicomponent fiber may be such that the fiber is heated to a temperature during the thermoforming process such that the low melting point polymer can melt and bond the fibers into an intact web. Typically, the higher melting point polymer of the bicomponent fiber provides structural integrity to the web and does not melt at either the thermal bonding temperature or the use temperature. Thus, the fiber web is heated to a temperature above the melting point or glass transition temperature of the low melting point polymer and below the melting point or glass transition temperature of the high melting point polymer. In an embodiment, melt fusion is achieved when the melted or softened fiber component comes into contact with other bicomponent fibers and any other fibers and additives in the formed filter material.

[0053] For example, in one embodiment, the bicomponent fiber may include a low melting point polymer having a melting point of at least 100° C., at least 120° C., or at least 140° C. In some embodiments, the melting point of the lower melting point polymer ranges from 140° C. to 160° C. The bicomponent fiber may further include a higher melting point polymer having a melting point of at least 235° C. or at least 240° C. In some embodiments, the higher melting point polymer melting point ranges from 240° C. to 260° C.

[0054] Without being bound by theory, it is believed that the relatively low melting point polymer of the bicomponent fibers melts under sheet, media, or filter forming conditions and bonds the bicomponent fibers and other fibers present in the media to mechanically stabilize the sheet, media, or filter, while the higher melting point polymer of the bicomponent fibers does not melt and therefore holds the other fibers in the web apart, which would be beneficial in maintaining the low stiffness structure of the media during the thermoforming process.

[0026]

[0055] In some embodiments, the media may include a first bicomponent fiber and a second bicomponent fiber, the second bicomponent fiber having different characteristics than the first bicomponent fiber may improve the ease of forming the fibers into sheets, layers, and / or filter media.

[0056] For example, the first bicomponent fiber may comprise a low melting point polymer having a melting point of at least 100° C., at least 120° C., or at least 140° C. In some embodiments, the melting point of the lower melting point polymer ranges from 140° C. to 160° C. The first bicomponent fiber may further comprise a higher melting point polymer having a melting point of at least 235° C. or at least 240° C. In some embodiments, the melting point of the lower melting point polymer ranges from 235° C. to 260° C. The first composite fiber may range from 0% to 30% by weight of the filter material. In some embodiments, the first composite fiber may range from 10% to 20% by weight of the filter material.

[0057] In such examples, the second bicomponent fiber may include a low melting point polymer having a melting point of at least 80° C., at least 90° C., or at least 100° C. In some embodiments, the melting point of the lower melting point polymer ranges from 90° C. to 120° C., or from 105° C. to 115° C. The second bicomponent fiber may further include a higher melting point polymer having a melting point of at least 200° C., at least 220° C., or at least 240° C. In some embodiments, the melting point of the higher melting point polymer ranges from 235° C. to 260° C. The second composite fiber may range from 0% to 40% by weight of the filter material. In some embodiments, the second composite fiber may range from 10% to 20% by weight of the filter material. In yet another example, the second composite fiber may range from 30% to 45% by weight of the filter material.

[0058] The fiber diameter of the bicomponent fibers is usually in the range of 5 μm to 50 μm, and often in the range of 10 μm to 20 μm. The length of the bicomponent fibers is usually in the range of 0.1 millimeters (mm) to 20 mm, and often from about 0.2 mm to about 15 mm. The linear density of the bicomponent fibers may be in the range of about 1 dtex to 5 dtex or 2 dtex to 4 dtex.

[0059] Bicomponent fibers can be made from any suitable material including a variety of thermoplastic materials including, for example, polyolefins (polyethylene, polypropylene, etc.), polyesters (polyethylene terephthalate, PET, polybutylene terephthalate, PBT, etc.), nylons (nylon 6, nylon 6,6, nylon 6,12, etc.). Any thermoplastic material with a suitable melting point can be used in the bicomponent fibers, while a higher melting point polymer can be used in the higher melting point portion of the fiber. Bicomponent fibers can include, for example, PET / PET, or PET / nylon 6 / nylon 6,6 constructions with components of different melting points, or nylon.

[0060] Exemplary bicomponent fibers include polyolefin / polyester (sheath / core) bicomponent fibers, whereby the polyolefin, e.g., polyethylene sheath, melts at a lower temperature than the core, e.g., polyester or polyester / polyester or nylon / nylon materials. Typical thermoplastic polymers include polyolefins, e.g., polyethylene, polypropylene, polybutylene, and copolymers thereof; polytetrafluoroethylene; polyesters, e.g., polyethylene terephthalate; vinyl acetates, e.g., polyvinyl acetate, polyvinyl chloride acetate; polyvinyl butyral; acrylics, e.g., polyacrylate, and polymethyl acrylate, polymethyl methacrylate; polyamides, e.g., nylon; polyvinyl chloride, polyvinylidene chloride; polystyrene; polyvinyl alcohol; polyurethane; cellulosics, e.g., cellulose nitrate, cellulose acetate, cellulose acetate butyrate, ethyl cellulose, and the like; copolymers of any of the above materials, e.g., ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, styrene-butadiene block copolymers, Kraton rubber, and the like.

[0027] Irregular rayon fiber

[0061] In various embodiments, filter materials consistent with the technology disclosed herein have irregular rayon fibers distributed among binder fibers. The surface properties of rayon can advantageously improve coalescence in liquid hydrocarbon filtration. Additionally, the irregular shape of the rayon fibers can relatively reduce the stiffness of the media and relatively increase the average pore size of the filter material, which can advantageously improve the coalescence ability of the filter material. Additionally, the irregular shape of the rayon fibers can provide a relatively rough surface for the fibers, which can advantageously improve the coalescence properties of the fibers.

[0062] The filter material may generally be at least 35%, 40%, or 50% by weight of irregular rayon fibers. The filter material generally has no more than 65% or 60% by weight of irregular rayon fibers. In some embodiments, the filter material has between 50% and 60% by weight of irregular rayon fibers. The linear mass density of the irregular rayon fibers is between 1 den (denier) and 7 den, or between 2 den and 5 den, and the length of the irregular rayon fibers may range, in some embodiments, from 1 mm to 10 mm, from 3 mm to 8 mm, or from 5 mm to 7 mm.

[0063] Irregular rayon fibers are generally not fibrillated and may have a relatively large cross-section compared to fibrillated fibers. In some embodiments, the irregular rayon fibers are lobed rayon fibers. The irregular rayon fibers may be multilobal rayon fibers, such as bilobal, trilobal, tetralobal, hexalobular, and octalobular rayon fibers. In one example, the irregular rayon fibers are trilobal rayon fibers. However, other irregular fiber cross-sectional shapes, such as deep grooved fibers, are certainly contemplated.

[0028] Fibrillated rayon fiber

[0064] In various embodiments, the filter material comprises fibrillated rayon fibers. As described above, the surface properties of rayon can advantageously improve coalescence in liquid hydrocarbon filtration, such as by promoting the growth of the dispersed phase in the media and the release of the dispersed phase from the media. Fibrillated rayon fibers have a relatively high surface area and can generally act as a coalescer for the dispersed phase, such as water or air, in liquid hydrocarbon streams, such as fuel or oil. Combining fibrillated rayon fibers with irregular rayon fibers can advantageously improve the coalescence of the dispersed phase, by forming pores in the filter material with a relatively wide pore size distribution. Furthermore, if the fibrillated fibers are entangled during the manufacturing process, the strength of the filter material can be advantageously increased.

[0029]

[0065] In one embodiment, the fibrillated rayon fibers have an affinity for the outer surface of the binder fiber, and therefore can cover the exposed surface of the binder fiber. Such a configuration can advantageously limit the ability of the binder fiber to inhibit coalescence by limiting contact between the surface of the binder fiber and the liquid being filtered. Figure 1 is an SEM image showing an example of a binder fiber 10 with a polyester outer surface that is thermally bonded to a fibrillated rayon fiber 12 (lyocell). The fibrillated rayon fiber 12 wraps around the binder fiber 10 and entangles to limit or prevent water droplets 14 in the fuel 16 from contacting the binder fiber 10. In this example, the binder fiber is a bicomponent binder fiber with a sheath-core structure with a polyester inner core and a polyester outer sheath.

[0066] The fibrillated rayon fibers may be 5% to 15% of the mass of the filter material. In some embodiments, the fibrillated rayon fibers may be 5% to 10% of the mass of the filter material. In some embodiments, the fiber diameter of the fibrillated rayon fibers ranges from 50 to 1000 nanometers or 50 to 500 nanometers. The linear mass density of the fibrillated rayon fibers may be 0.0001 den to 0.0007 den. In one embodiment, the fibrillated rayon fibers are fibrillated lyocell fibers manufactured by Engineered Fibers Technology, LLC of Shelton, Connecticut.

[0030] Natural Cellulose Fibers

[0067] In some embodiments, the filter material has a relatively low amount of natural cellulose fibers. Natural cellulose fibers can advantageously improve the strength of the wet fiber slurry for the wet manufacturing process step of the filter material. Generally, the filter material has less than 10% natural cellulose fibers by weight. In some embodiments, the filter material has 6% or less natural cellulose fibers by weight. However, in some embodiments, the filter material has no natural cellulose fibers, meaning that the filter material has less than 3% natural cellulose fibers by weight, less than 1% natural cellulose fibers by weight, less than 0.5% natural cellulose fibers by weight, or 0% natural cellulose fibers by weight. In some embodiments, natural cellulose fibers can interfere with the performance of the filter material. In some embodiments, it is desirable to have 0% natural cellulose fibers in the filter material.

[0031] Manufacturing Process

[0068] In making the filter material, in certain embodiments, a fiber mat is formed using a wet process. The mat is heated to melt the binder fibers and bond the fibers internally to form the media. The binder fibers bond to each other and to the rest of the fibers in the fiber mat to fuse into a mechanically stable media.

[0069] Filter materials are typically made using a papermaking process. However, in certain other embodiments, the media may be made by an airlaid process using similar components adapted for airlaid processing. Machines used in wet sheet production include hand-laid sheet machines, Fourdrinier machines, cylinder machines, tilt machines, combination machines, and other machines that can take a suitable mix of paper, form layers of furnish components, and remove the fluid aqueous components to form a wet sheet.

[0070] In an example of wet processing, the medium is made from an aqueous furnish that includes a dispersion of fibrous material in an aqueous medium. The aqueous liquid of the dispersion is typically water, but may include various other materials such as pH adjusting materials, surfactants, defoamers, fire retardants, viscosity modifiers, medium treatments, colorants, etc. The aqueous liquid is drained from the dispersion, usually by placing the dispersion on a screen or other perforated support that holds the dispersion of solids, and draining the liquid to obtain a wet paper composition. Once the wet composition is formed on the support, it is typically further dewatered by vacuum or other pressure, and further dried by evaporating the remaining liquid. After the liquid is removed, thermal bonding occurs, usually by melting some of the binder fibers, resin, or other parts of the formed material. The molten material bonds the parts into layers.

[0071] The material-containing fibrous slurry is typically mixed to form a relatively uniform fibrous slurry. The fibrous slurry is then subjected to a wet-laid papermaking process. Once the slurry is formed into a wet-laid sheet, the wet-laid sheet can be dried, cured, or otherwise treated to form a dry, permeable, but true sheet, media, or filter. In commercial-scale processes, the bicomponent mat is generally processed using papermaking type machines such as commercially available Fourdrinier, wire cylinder, Stevens former, rotoformer, Invar former, bench former, and inclined delta former machines.

[0072] In some embodiments, an inclined delta former is utilized. The bicomponent mat can be prepared, for example, by forming a pulp and glass fiber slurry and combining the slurries in a mixing tank. The amount of water used in this process can vary depending on the size of the equipment used. The furnish can be passed through a conventional headbox where it is dewatered and deposited on a moving wire screen where it is dewatered by suction or vacuum to form a nonwoven bicomponent web. The web can then pass through a drying section where the mat is dried, any additives are cured, and the binder fibers are heated to thermally bond the filter material. The resulting mat can be collected on a large roll for future processing, lamination to other media layers, or formed into filter elements.

[0032] Test results Fuel-water separation efficiency test

[0073] The sample filter materials were tested for fuel-water separation efficiency. Each sample of filter material (180 mm x 150 mm) was wrapped around a perforated aluminum cylinder (59 mm diameter x 150 mm height) to form a filter. The aluminum cylinder served as a rigid core to provide structural integrity to the filter material. The ends of the filter material were sealed to the core and edge seams using a two-part epoxy adhesive. The wrap and core were then attached and sealed to plastic filter end caps with a two-part epoxy adhesive. Both end caps have a central hole through which fluid can flow. The bottom end cap allows the denser, coalesced water phase to settle by gravity into a drainable collection bowl. The top end cap allows the fuel flow to exit the filter.

[0074] To measure the fuel water separation efficiency, the prototype filter was tested on a bench built to the specifications of ISO 16332:2018. Deviations from the standard test procedure are listed herein. The flow through the test filter was set at 4.0 liters per minute (L / min). The challenge droplet size was adjusted to the desired mean emulsion diameter (90 μm, 75 μm, and 45 μm) using an adjustable orifice plate with a needle valve. The droplet size distribution of the upstream free water was determined using a commercially available Malvern Instruments (Malvern, UK) Insitec SX droplet size analyzer fitted with a wet flow cell. The free water content upstream and downstream of the filter was measured using a commercially available Litronic-FMS / RMH12 sensor (Liebherr-Mischtechnik GmbH, Germany). Water was injected using an adjustable peristaltic pump. The water injection flow rate was adjusted to target 1500 parts per million (ppm) free water. The lap samples were tested for 30 minutes at each target average droplet diameter, starting with a challenge diameter of 90 μm, 75 μm, then 45 μm. The reported water separation efficiency is the average efficiency [(upstream free water - downstream free water) / upstream free water] for the 30 minutes of testing at each challenge diameter.

[0075] Ultra-low sulfur diesel from Chevron Phillips Chemical (The Woodlands, TX) was used as the base fuel. 10% (volume) soybean biodiesel (Renewable Energy Group (REG), Inc., Mason City, IA) was added to the base fuel to form the fuel blend. The interfacial tension of the fuel blend, measured by the pendant drop method, was 21.0 ± 0.2 dynes / cm. The same batch of fuel blend was used for all tests.

[0076] Each filter material sample was tested for fuel water separation efficiency at each average droplet size with the results shown in Table 1 below. Each sample was a thermally bonded wet media with no non-fibrous resin. The filter material samples tested each had various weight percent trilobal rayon fiber ("TL Rayon"), 0.8 den rayon fiber with a circular cross section ("0.8d Reg. Rayon"), fibrillated rayon fiber ("Fil."), polyester ("PET"), and natural cellulose ("Nat."). Each filter material sample tested had a variety of basis weights ("Bas. Weight") and permeability ("Permeation") values.

[0033] [Table 1]

[0077] The fuel-water separation efficiency for each average droplet size of each sample referenced in Table 1 is shown in the graph of FIG. 5. Although it was generally expected that filter materials with more rayon fiber would have a higher fuel-water separation efficiency than those with less rayon, it was surprising that the combination of rayon fiber types seemed to affect the fuel-water separation efficiency. For example, comparing Sample 5 to Sample 6, Sample 5 had significantly lower fuel-water separation efficiency, even though it had 1.4% less rayon fiber and 1.4% more polyester fiber than Sample 6. The significantly increased permeability of Sample 6 compared to Sample 5, which was obtained by replacing the non-irregular and non-fibrillated rayon fiber of Sample 5 with the trilobal (irregular) and fibrillated rayon fiber of Sample 6, may advantageously increase the water separation efficiency. It is believed that the increased surface area of ​​the rayon fiber in Sample 6 (through a relatively high proportion of fibrillated and trilobal fibers in combination) may advantageously improve the water separation efficiency of the filter material, compared to the other samples.

[0078] The fuel water separation efficiency of the sample is also compared in Figure 5 to a commercially available filter material product (Product 1). Product 1 is an airlaid media comprised of 30% by weight polyester fibers and 70% by weight non-irregular, non-fibrillated rayon fibers. Product 1 does not contain a non-fibrous resin binder. Furthermore, the polyester fibers in Product 1 are not binder fibers, and Product 1 does not contain binder fibers, specifically 0% by weight binder fibers. Rather, the polyester and rayon fibers are bonded together by a needle punch process that intertwines the constituent fibers. Product 1 has a basis weight of 102±10 g / m 2 , 1.4±0.14 mm thickness, and longitudinal tensile strength of 0.72 N / cm to 7.2 N / cm. The machine direction tensile strength was measured as described above in "Definitions," except that the width of the cross machine direction specimens was approximately 50.8 mm (twice the procedure above) to allow for a better performance of the test procedure given the relative brittleness of the materials. Both the burst strength and Gurley stiffness of Product 1 are too low to be measured by the test procedures disclosed herein.

[0079] Since the openings between the fibers in the media can promote the growth of the dispersed phase, it is believed that Product 1 has a relatively low toughness and a low pressure drop, which is desirable for coalescence performance. However, without being bound by theory, it is believed that Product 1 is relatively weak, which may cause the media to collapse with increasing fluid flow, leading to increased toughness, reduced pore size, and increased pressure limitations during use, limiting coalescence performance compared to similar filter materials in the technology disclosed herein. Furthermore, the relatively low strength of the material of Product 1 may be undesirable in many automated manufacturing processes, where a compressible, weak media may be difficult to form into a filter element.

[0034] Filter material performance under load

[0080] A series of prototype filter assemblies were constructed and installed in Class 8 long-haul diesel engine trucks. The filters in the filter assemblies were identical, but different coalescence growth wraps were placed downstream of the filters for comparison. The comparative wraps were the same wraps constructed from Product 1 above. The example wraps were the same wet-laid rayon / binder fiber filter material as in the technology disclosed herein. The example wraps were 38% PET fibers, 7% fibrillated lyocell fibers, and 55% trilobal rayon fibers. The comparative and example wraps were installed in filter assemblies of the same construction and used in the same type of truck. However, the operating environments of the trucks were different, and therefore the conditions of the filter assemblies were different.

[0081] Trucks with filter assemblies installed were driven between 3,000 and 65,000 miles. Filter assemblies were removed from the trucks at different mileage intervals and tested for fuel water separation efficiency. The test protocol was per ISO 16332:2018 with the average challenge droplet diameter set at 150 μm. Prior to testing, the differential pressure of each filter assembly was measured. The differential pressure was higher due to a relatively high contaminant load on the filter assembly. Among the filter assemblies that measured a differential pressure of 5 kPa to 15 kPa, which correlates to a filter assembly that is contaminant loaded but still within its useful life, the filter assemblies with the comparative wrap had an average fuel water removal efficiency of 80.8%, while the filter assemblies with the example wrap had an average fuel water removal efficiency of 91.2%.

[0082] High conductivity ultra-low sulfur diesel from Corrigan Oil (Brighton, MI) was used as the base fuel for the fuel water removal efficiency test. 10% (volume) soybean biodiesel from Corrigan Oil (Brighton, MI) was added to the base fuel to form the fuel blend. The interfacial tension of the fuel blend was 14.0 ± 0.5 dynes / cm as measured by the pendant drop method. The same batch of fuel blend was used for all tests.

[0035] Filter Assembly

[0083] A filter assembly consistent with the technology disclosed herein generally incorporates the filter material described herein. The filter material is generally configured to be disposed downstream of other media in the filter assembly. In some embodiments, the filter assembly may be a single filter element incorporating the filter material. In such an example, the filter material is disposed in a most downstream position relative to other media in the filter assembly. In some other embodiments, the filter assembly may be multiple filter elements, with the filter material consistent with the present disclosure being incorporated into a second filter element configured to be disposed downstream of a first filter element. In such an example, the first filter element may have a particle filtration layer and a coalescing layer.

[0084] A filter assembly similar to the technology disclosed herein generally includes a filter material, a coalescence layer downstream of the filter material, and a growth medium downstream of the coalescence layer. The growth medium is similar to the filter material described above.

[0036] Filter Assembly Configuration

[0085] 2A and 2B show an exemplary filter assembly 100 in one embodiment. Filter assembly 100 generally includes a particulate filtration layer 110, a coalescing layer 120, and a growth medium 130. In this example, filter assembly 100 is a filter element and is configured for installation in a filtration system.

[0086] Particle filtration layer 110 is generally configured to filter particles from a liquid stream, such as a liquid hydrocarbon stream, examples of which include fuel and oil. In various embodiments, particle filtration layer 110 is disposed upstream of coalescing layer 120. In various embodiments, particle filtration layer 110 is located upstream of a growth medium. Certain exemplary fibers and other materials of particle filtration layer 110, as well as certain properties of particle filtration layer 110, are described in more detail below.

[0087] The coalescing layer 120 is disposed downstream of the particulate filtration layer 110 with respect to the flow of fluid through the filter assembly 100. The coalescing layer 120 may generally include one or more layers of a coalescing medium configured to coalesce dispersed phases in a liquid hydrocarbon stream. In certain embodiments, the coalescing medium is configured to coalesce water in a fuel stream. In certain embodiments, the coalescing medium is configured to coalesce air in a hydraulic oil stream. In certain embodiments, the coalescing layer 120 is bonded to the particulate filtration layer 110. Certain exemplary fibers and other materials of the coalescing layer 120, as well as certain properties of the coalescing layer 120, are described in more detail below.

[0088] The growth medium 130 is a layer disposed downstream of the coalescing layer 120. In some embodiments, the growth medium 130 is directly bonded to the coalescing layer 120. In other illustrated embodiments, the growth medium 130 is directly bonded to the support layer 122, which is directly bonded to the coalescing layer 120. Exemplary support layers, including materials used to construct the exemplary support layers, are described in more detail below. In some other embodiments, additional support layers can be bonded to the particle filtration layer 110. The support layers can be bonded upstream of the particle filtration layer 110 or downstream of the particle filtration layer 110, and can be in addition to or in place of the support layer 122 bonded downstream of the coalescing layer 120.

[0089] In this example, the particle filtration layer 110, coalescence layer 120, and growth media 130, collectively referred to as a "filter media assembly" 104 for purposes of illustration in this figure, are stacked in series across the fluid flow path 102. The layers of the filter media assembly 104 are pleated together to collectively define a plurality of pleats 140 extending between a first set of pleat folds 142 and a second set of pleat folds 144. The first set of pleat folds 142 define a first face (element number 142) and the second set of pleat folds 144 define a second face (element number 144). The first face 142 and the second face 144 are flow faces of the filter element, meaning that fluid flow is directed through the filter element for filtration purposes. In certain other embodiments, the filter media assembly is a sheet of media wrapped in a helical configuration about a longitudinal axis x.

[0090] The particle filtration layer 110, the coalescing layer 120, and the growth media 130 collectively define a tubular structure. In particular, the first set of pleat folds 142 collectively define an outer circumferential limit 111a of the filter media assembly 104, and the second set of pleat folds 144 collectively define an inner circumferential limit 111b of the filter media assembly 104. In this example, the inner circumferential limit 111b of the filter media assembly 104 is the inner radial boundary 119 of the filter media assembly 104 (second pleat fold set 144). The outer circumferential limit 111a is the outer radial boundary 117 (first pleat fold set 142).

[0037]

[0091] In various examples, the filter assembly 100 has a central passageway 106, a first end cap 150 that couples to a first media end 112 of the filter media assembly 104, and a second end cap 152 that couples to a second media end 114 of the filter media assembly 104. The filter assembly 100 defines a fluid flow passageway 102 that extends through the filter media assembly 104. The filter media assembly 104 and the central passageway 106 share a central axis x, which extends in a longitudinal direction (as viewed in FIG. 2A ).

[0092] In some embodiments, the structural support 154 (such as the first structural support 154) can abut the filter media assembly 111 along its inner circumferential limit 104b. Indeed, in some embodiments, the structural support 156 (such as the second structural support 156) surrounds the outer circumferential limit 104a of the filter media assembly 111. The structural supports 154, 156 are generally configured to provide mechanical support to the filter media assembly 104, for example, to prevent the filter media assembly 104 from collapsing when subjected to an applied force when liquid passes through it. The structural supports 154, 156 generally do not exhibit particle filtration efficiency and are more permeable than the filter media assembly 104. The structural supports 154, 156 may be tubular metal or plastic support screens that abut the inner and / or outer circumferential boundaries 111b / 104a of the filter media assembly 111. In some embodiments, one or both of the structural supports 154, 156 can be omitted.

[0093] 2A , the first media end 112 of the filter media assembly 104 is coupled to a first end cap 150 and the second media end 114 of the filter media assembly 104 is coupled to a second end cap 152. The filter media assembly 104 defines a central passageway 106 that extends from the first media end 112 to the second media end 114. In this example, the central passageway 106 defines a portion of the fluid flow passage 102. In this example, the fluid flow passageway 102 extends through the second end cap 152 and through the second media end 114 of the filter media assembly 104.

[0094] The first end cap 150 is generally configured to retain the first media end 112 of the filter media assembly 104 and define a portion of the fluid flow path 102 through the filter media assembly 104. The first end cap 150 is coupled to the first media end 112. The first end cap 150 has a first media potting structure 123 configured to receive the first media end 112 of the filter media assembly 104. In some embodiments, the first media potting structure 123 of the first end cap 150 is also configured to receive any structural supports 154, 156. The first media potting structure 123 is defined by an annular surface 124 that abuts the first media end 112 of the filter media assembly 104, an inner tubular flange 125, and an outer tubular flange 126. The inner tubular flange 125 extends longitudinally from the annular surface 124 into the central passageway 106. The inner tubular flange 125 abuts a first structural support 154 of the filter media assembly 104. The outer tubular flange 126 extends longitudinally from the annular surface 124 abutting a second structural support 156. In various embodiments, the first media potting structure 123 and the first media end 112 of the filter media assembly 104 are joined with an adhesive / sealant disposed within the first media potting structure 123.

[0095] The first end cap 150 has a circumferential sealing surface 128 about a longitudinal axis x configured to form a seal with a filtration system component, as described in more detail below. The circumferential sealing surface 128 shares a central axis x with the filter media assembly 104 and the central passageway 106. The circumferential sealing surface 128 may be a circumferential cavity configured to receive a resilient component, such as an O-ring 127. In some embodiments, the circumferential cavity is discontinuous, while in other embodiments, the circumferential cavity is continuous.

[0096] The second end cap 152 is generally configured to retain the second media end 114 of the filter media assembly 104 and define a portion of the fluid flow path 102 through the filter media assembly 104. In this example, the second end cap 152 defines a filter element outlet 151 of the fluid flow path 102. The second end cap 152 includes a second media potting structure 134 configured to sealingly receive the second media end 114 of the filter media assembly 104. The second media potting structure 134 is defined by an annular surface 132 that abuts the second media end 114 of the filter media assembly 104 and an outer tubular flange 133. The outer tubular flange 133 extends longitudinally from the annular surface 132 beyond the outer radial boundary 117 of the second media end 114 of the filter media assembly 104. In various embodiments, the second media potting structure 134 and the second media end 114 of the filter media assembly 104 are joined with an adhesive / sealant disposed within the second media potting structure 134 .

[0097] It should be noted that the technology disclosed herein is not limited by any particular configuration of the end caps of the filter assembly. Additionally, various other filter assembly configurations may be used. For example, while the cylindrical filter elements disclosed herein are shown and described with a flow direction from outside to inside, in other examples, the flow direction of the filter assembly may be configured as inside to outside.

[0098] FIG. 3A is a first cross-sectional view of another exemplary configuration of a filter assembly 200 according to an exemplary embodiment, and FIG. 3B is a second cross-sectional view of the filter assembly 200 of FIG. 3A. The filter assembly 200 is a filter element generally consistent with the above description of the filter assembly with reference to FIGS. 2A-2B, except where inconsistent with the present description or corresponding figures. In this example, the particle filtration layer 210 and the coalescing layer 220 are stacked in series and pleated together. The particle filtration layer 210 and the coalescing layer 220 collectively define a tubular structure with a central opening 206 similar to the above example. However, the growth medium 230 forms a tube without pleats within the central opening 206. The growth medium 230 can be wrapped or coiled around the internal structural support 254 in some examples. In this example, the growth medium 230, particle filtration layer 210, and coalescing layer 220 are collectively contained within a first end cap 250 and a second end cap 252 (FIG. 3A) to form a filter assembly, although in other embodiments, the growth medium 230 may be separate from the end caps.

[0099] Figure 4A is a first cross-sectional view of yet another exemplary configuration of a filter assembly 300 according to an exemplary embodiment. Figure 4B is a second cross-sectional view of the exemplary filter assembly 300 consistent with Figure 4A. Filter assembly 300 generally includes a particulate filtration layer 310, a coalescing layer 320, and a growth medium 330. Filter assembly 300 may be a filter element configured for installation in a filtration system.

[0100] The configuration of particle filtration layer 310 and coalescing layer 320 is similar to that described in the description of Figures 2A-3B, except where inconsistent with this description or the corresponding figures. In particular, coalescing layer 320 is disposed downstream of particle filtration layer 310. Coalescing layer 320 and particle filtration layer 310 are pleated to collectively define a tubular structure with a central opening 306. In some embodiments, support layer 332 may be coupled to one of coalescing layer 320 or particle filtration layer 310, or to both coalescing layer 320 and particle filtration layer 310. In such embodiments, support layer 332 may be pleated along with particle filtration layer 310 and coalescing layer 320. Particle filtration layer 310, coalescing layer 320, and any support layer 332 may define a filter media assembly of the filter assembly. In this example, support layer 332 is coupled to coalescing layer 320 and disposed downstream of coalescing layer 320.

[0101] In some embodiments, the internal structural support 354 may be positioned to abut the inner circumferential boundary 319 that defines a first flow face of the filter media assembly 304. However, the internal structural support 354 may be omitted. In some embodiments, the outer structural support (not shown) may be positioned to abut the outer circumferential boundary 317 that defines a second flow face of the filter media assembly 304.

[0102] Similar to the above example, the growth medium 330 is disposed downstream of the coalescing layer 320. In one embodiment, the growth medium 330 is positioned within the internal structural support 354, specifically within the central opening 306 defined by the filtration media assembly 304. However, unlike the above embodiment, in this example, a radial gap 305 is defined within the central opening 306 between the coalescing layer 320 and the growth medium 330.

[0103] The filter assembly 300 may have an inner core 360 ​​disposed within the central opening 306. The inner core 360 ​​may be defined about a central axis x. The inner core 360 ​​may be a permeable structural feature secured to one or both of the end caps 350, 352. The inner core 360 ​​defines a portion of the fluid flow path 302. The inner core 360 ​​may be configured, among other things, to receive fluid that has passed through the layers of filter media (e.g., the particulate filtration layer 310, the coalescing layer 320, and the growth medium 330). Thus, the inner core 360 ​​is disposed downstream of the particulate filtration layer 310, the coalescing layer 320, and the growth medium 330.

[0104] In this example, the growth medium 330 is a sheet of filter material wrapped in a spiral configuration around the inner core 360, forming multiple layers of the growth medium 330 arranged in series across the fluid flow path 302. Thus, the growth medium 330 is a tubular structure. The growth medium 330 may be coupled to the inner core 360, such as by being coupled along an end of the growth medium 330 to the length of the inner core 360 ​​and then coiled around the inner core 360.

[0105] In various examples, the filter assembly 300 has a central opening 306, a first end cap 350 coupled to a first media end 312 of the filter media assembly 304, and a second end cap 352 coupled to a second media end 314 of the filter media assembly 304 (FIG. 4A). The filter assembly 300 defines a fluid flow passage 302 that extends through the filter media assembly 304. The filter media assembly 304 and the central opening 306 share a central axis x, which extends in a longitudinal direction.

[0106] In one embodiment, the filter assembly 300 is configured to maintain separation between the coalesced dispersed phase and the liquid hydrocarbons after filtration. In this embodiment, the filter assembly 300 defines two branches of the fluid flow path 302 downstream of the growth medium 330: a coalesced path 302a and a separated hydrocarbon path 302b. In this example, a porous barrier 370 is disposed within the filter assembly 300 across the fluid flow path 302 downstream of the growth medium 330. The porous barrier 370 is configured to generally allow the passage of the continuous phase (such as liquid hydrocarbons) but not the passage of the smallest coalesced dispersed phase (such as water droplets or air pockets). The coalesced path 302a extends out of the filter assembly 300 from the interstitial region 362 upstream of the porous barrier 370 and downstream of the growth medium 330. The separated hydrocarbon path 302b extends from the filter assembly 300 downstream of the porous barrier 370.

[0107] In this example, the porous barrier 370 is a tubular screen structure with a first end coupled to the first end cap 350 and a second end coupled to the second end cap 352. In some embodiments, the porous barrier 370 has a pleated tubular structure. Exemplary structures of the porous barrier 370 and specific properties of the porous barrier 370 are described in more detail below.

[0108] Although the exemplary filter assemblies shown and described herein are cylindrical filter elements, it will be understood that the growth media described herein can be incorporated into filter assemblies in a variety of different configurations. For example, a filter assembly similar to the technology disclosed herein may include a panel filter. Multiple panel filters may be incorporated into the filter assembly, with each panel filter being arranged in series with an adjacent panel filter. In other examples, a single panel filter may be used in the filter assembly, with the particle filtration layer, coalescing layer, and growth medium being arranged in succession in layers across the fluid flow path defined by the panel filter.

[0038] particle filtration layer

[0109] The particulate filtration layer can be constructed of a variety of materials and combinations of materials known in the art. The particulate filtration layer can be a single layer or multiple layers of filtration media.

[0110] The particle filtration layer may generally be composed of media fibers and a binder. "Media fibers" herein are defined as fibers that provide functional filtration properties to the layer. Media fibers may be, for example, glass fibers, carbon fibers, ceramic fibers, polyester, or natural cellulose. Exemplary embodiments of the particle filtration layer may use a significant percentage of glass fibers. In some embodiments, suitable alternative fibers for the media fibers include glass fibers as well as carbon fibers, natural cellulose fibers, and / or polyester fibers. In some embodiments, the media fibers are staple fibers. In general, the average diameter of suitable carbon fibers should be less than 25 microns, more desirably less than 15 microns, and preferably less than 10 microns. Commercial sources of suitable carbon materials include the following: Unitika, Kynol, and others.

[0111] In an embodiment, the particle filtration layer contains glass fibers in an amount equivalent to about 10% to 90% by weight of the total solids in the particle filtration layer, or about 20% to 80% by weight of the total solids in the particle filtration layer, or about 25% to 75% by weight of the total solids in the particle filtration layer, or about 50% by weight of the total solids in the particle filtration layer. In an embodiment, a blend of two or more glass fiber sources is used, and a blend of two or more glass fiber sources is used to form the total mass ratio of glass fibers in the particle filtration layer. In such an embodiment, the blend of glass fiber sources is selected to control the permeability of the particle filtration layer. For example, in an embodiment, the permeability of the particle filtration layer is increased when glass fibers from two or more sources are combined in various ratios, including glass fibers having an average fiber diameter of about 0.3 to 0.5 micrometers, glass fibers having an average fiber diameter of about 1 to 2 micrometers, glass fibers having an average fiber diameter of about 3 to 6 micrometers, glass fibers having an average fiber diameter of about 6 to 10 micrometers, and glass fibers having an average fiber diameter of about 10 to 100 micrometers. In this embodiment, the pore size of the particulate filtration layer is controlled by selection of the glass fiber blend to provide the desired permeability.

[0112] The particle filtration layer also typically includes a binder. In some embodiments, the binder may be a non-fibrous resin. Typically, the binder is a binder fiber, such as the bicomponent fibers described above with respect to the filter material. In such embodiments, the particle filtration layer may be free of a non-fibrous resin.

[0113] The performance characteristics of the particle filtration layer are influenced by controlling the attributes of the particle filtration layer with respect to fiber size, pore structure, robustness, and compressibility. In general, media with relatively low robustness and low compressibility, while having relatively small mean flow pore size, but relatively large maximum flow pore size, provide exemplary media structures that can remove particulates without premature clogging. In certain embodiments, the particle filtration layer is hydrophilic in air, meaning that the contact angle between a water droplet in air and the surface of the filtration layer is less than 90 degrees, as measured using a standard contact angle measuring device, such as a First Ten Angstroms contact angle meter. The hydrophilicity of the particle filtration layer 110 is distinguishable from conventional meltblown materials that can be used for fuel particle filtration, which tend to be hydrophobic in air. "Hydrophobic in air" generally means that the contact angle between a water droplet in air and the surface of the media is greater than 90 degrees.

[0114] In some embodiments, the robustness level of the particle filtration layer is relatively low. In typical practice, the robustness of the particle filtration layer is less than 15%, more usually less than 12%, and more frequently less than 10%. In particular embodiments, the robustness is less than 9%, less than 8%, or less than 7%. The air permeability of the particle filtration layer is generally less than about 45 ft 3 / min·ft 2 ~about 200ft 3 / min·ft 2 The range is.

[0115] In some embodiments, a non-fibrous binder resin may be used to help bind the media fibers, and possibly the binder fibers, into a mechanically stable particle filtration layer. Such thermoplastic binder resin materials may be used as dry powders or solvent-based, but are typically aqueous dispersions of vinyl thermoplastic resins. Non-fibrous resins may be used, but are not necessary to provide sufficient strength for the particle filtration layer.

[0039] combined layer

[0116] The coalescing layer is generally disposed upstream of the growing media and downstream of the particulate filtration layer. The coalescing layer may be constructed with any coalescing layer known in the art. The coalescing layer may incorporate media fibers and binders. In some embodiments, the coalescing layer does not include bicomponent fibers.

[0117] The average fiber diameter of the coalesced layer may range from about 0.3 μm to about 10 μm, or from about 0.69 μm to about 7.5 μm. The thickness of the coalesced layer may generally range from about 0.3 mm to about 1.0 mm when measured at 8 psi (55.1 kPa). In some embodiments, the thickness of the coalesced layer may range from about 0.4 mm to about 0.7 mm when measured at 8 psi (55.1 kPa). The basis weight of the coalesced layer is generally about 50 g / m 2 ~Approx. 150g / m 2 , or about 80 g / m 2 ~Approx. 115g / m 2 In some embodiments, the basis weight of the coalescing layer may be greater than the basis weight of the particle filtration layer. The air permeability of the coalescing layer may be less than the air permeability of the particle filtration layer. In some embodiments, the air permeability of the coalescing layer is greater than about 3 ft 3 / min·ft 2 ~ approx. 70ft 3 / min·ft 2 In one embodiment, the air permeability of the coalesced layer is in the range of 10 ft 3 / min·ft 2 ~40ft 3 / min·ft 2 The range is.

[0118] In various embodiments, the coalescing layer is a wet media. The coalescing layer may consist essentially of fibers, surface treatments, and binder materials, meaning that at least 95%, 98%, or 100% by weight of the coalescing layer is fibers, surface treatments, and binder materials. In some embodiments, the coalescing layer is a nonwoven fiber mat coated with a surface treatment, and the fibers are bonded with a binder material. The surface treatment generally alters the surface energy of the fibers, and the binder material is generally configured to bond the fibers of the coalescing layer.

[0119] The fibers of the coalescing layer may be various fibers and combinations of fibers, and are generally nonwoven. The fibers of the coalescing layer may be glass fibers, natural fibers, synthetic fibers, polymeric fibers, ceramic fibers, metal fibers, carbon fibers, and combinations thereof. Of course, other types of fibers are possible. In some embodiments, the coalescing layer includes glass fibers and polyester fibers. The fibers may be 50% to 95% by weight of the coalescing layer. In some embodiments, the coalescing layer is at least 70% by weight glass fibers. In some embodiments, the coalescing layer is at least 85% by weight glass fibers.

[0120] The surface treatment generally changes the surface properties of the fibers in the coalescing layer. The surface treatment may be of various configurations and compositions, and in some embodiments, the surface treatment is a fluorine-containing compound. One example of a surface treatment that may be used on the fibers of the coalescing layer is a polytetrafluoroethylene dispersion. Other exemplary surface treatments are fluoroalkyl acrylate polymers, perfluoroalkyl methyl acrylate copolymers, fluorinated hydrocarbons, fluoroacrylate polymers, fluoroalkyl methacrylate polymers, perfluoroalkoxy polymers (PFA), and fluorinated ethylene-propylene (FEP). The surface treatment may range from 0.01% to 25% by weight of the coalescing layer. In some embodiments, the surface treatment is 5% to 20% or 10% to 15% by weight of the coalescing layer.

[0040]

[0121] The binder material generally bonds the fibers in the coalescing layer. The binder material may be, for example, an acrylic resin or an epoxy. In one example, the binder material is an acrylic latex binder. In one example, the binder material is a styrene / acrylonitrile copolymer resin. The binder material may be an emulsion polymer, a resin, an epoxy, a solution polymer, a styrene-acrylate, a styrene-butadiene, an acrylic, a vinyl acetate, an acrylonitrile, a urethane, a urea formaldehyde, a melamine formaldehyde, an acidified acrylate, a polyvinyl alcohol, and combinations thereof. In an embodiment, the binder material may include a polymer modified to include one or more functional groups. For example, the polymer may be functionalized to include additional carboxylates. The coalescing layer may be 3% to about 40% by weight of the binder material, alternatively about 5% to about 25% by weight of the binder material, or alternatively about 10% to about 20% by weight of the binder material.

[0041] support layer

[0122] Some embodiments of the filter element disclosed herein include a support layer. The support layer may be bonded to one or both of the particle filtration layer, the coalescing layer, or both. In some embodiments, the support layer is located upstream of the particle filtration layer and bonded to the particle filtration layer. In some embodiments, the support layer is located downstream of the coalescing layer and bonded to the coalescing layer. In yet other embodiments, the support layer is positioned between the particle filtration layer and the coalescing layer and bonded to both the particle filtration layer and the coalescing layer. The support layer may be constructed of a variety of materials and combinations of materials, but is generally configured to provide structural support to the particle filtration layer and the coalescing layer. In embodiments where the support layer is located downstream of the coalescing layer, the support layer may prevent the coalesced dispersed phase from emulsifying because the coalesced dispersed phase is released relatively intact from the filter material.

[0123] In some embodiments, the support layer is a bicomponent fiber. In some embodiments, the bicomponent fiber is a substantially continuous polyester fiber with a nylon sheath, such as Colback® from Bonar Inc., Asheville, North Carolina. In other embodiments, the support layer is a cellulosic material. In some embodiments, the support layer is a scrim, such as a nonwoven polyester scrim. In some embodiments, the polyester scrim is Reemay from Polymer Group, Inc., Charlotte, North Carolina. The support layer may be a combination of materials, such as natural cellulose and polyester. In some embodiments, the support layer is a wire mesh. The support layer may of course be other materials.

[0124] The support layer may also have one or more binding materials. For example, in one embodiment, the support layer is saturated with a phenolic resin or any other type of binder. The support layer may also be treated with one or more compositions to tailor the properties of the support layer. In one embodiment, the basis weight of the support layer is about 17 g / m 2 ~about 200g / m 2 The air permeability of the support layer is generally in the range of 200 ft 3 / min·ft 2 ~ approx. 1000ft 3 / min·ft 2 The range is.

[0125] It will be appreciated that the average diameter of the support layer may be larger than the average diameter of the media fibers of the particle filtration layer, or may include fibers having other average largest cross-sectional dimensions (such as diagonals).

[0042] Porous Barrier

[0126] As noted above, the porous barrier prevents the passage of the smallest coalesced dispersed phase (such as water droplets or air pockets) while allowing the passage of the continuous phase (such as liquid hydrocarbons). The porous barrier may be formed by one or more layers of material, which may be, for example, woven, molded, and / or wet laid. In some embodiments, the porous barrier is a screen material that defines openings smaller in size than the smallest coalesced dispersed phase (water droplets or air pockets) that the porous barrier is configured to block. The surface of the screen may be hydrophobic, for example, in embodiments in which the porous barrier is used to block condensed water.

[0127] The size of the openings may be uniform or may be non-uniform and include openings of various sizes. The pores of the porous barrier, also referred to as screen openings, are understood to mean holes (e.g., through holes) in the barrier. The pore size may be determined by ASTM E11 or optical imaging. The porous barrier may include openings of 5 μm or more, 10 μm or more, 15 μm or more, or 20 μm or more in size. The porous barrier may include openings of 1 mm or less, 750 μm or less, 500 μm or less, 250 μm or less, 200 μm or less, 150 μm or less, or 100 μm or less in size. In one example, the porous barrier includes openings of 10 μm to 250 μm, 15 μm to 200 μm, or 20 μm to 150 μm in size. In one example, the porous barrier is a 100 μm screen configured to block coalesced water droplets larger than 100 μm in diameter. In some embodiments, the openings of the porous barrier are uniform in size (e.g., have a narrow pore size distribution). For example, in some embodiments, at least some of the openings, a majority of the openings, at least 90% of the openings, at least 95% of the openings, or at least 99% of the openings of the porous barrier are within a size range specified herein, as determined by the total opening area of ​​the porous barrier. The values ​​described herein are determined by optical imaging. In one embodiment, substantially all of the openings of the porous barrier are within a size range specified herein.

[0128] The shape of the openings in the porous barrier may be any suitable shape. For example, the openings may be rectangular, square, circular, elliptical, or any other suitable shape. The shape may be determined by viewing the porous barrier from a direction perpendicular to the plane of the porous barrier. In some embodiments, the shape of the openings in the porous barrier is uniform. For example, in some embodiments, at least some of the openings in the porous barrier, a majority of the openings, at least 90% of the openings, at least 95% of the openings, or at least 99% of the openings are the same shape (e.g., rectangular, square, circular, elliptical, etc.).

[0129] The porous barrier may be made of a woven or non-woven material. For example, the porous barrier may be made of a woven mesh. The fiber or wire diameter (or maximum cross-sectional dimension of non-circular fibers or wires) of the woven mesh may be 0.01 mm or more, 0.05 mm or more, or 0.1 mm or more. The wire diameter (or maximum cross-sectional dimension) of the woven mesh may be 10 mm or less, 2 mm or less, 1 mm or less, or 0.5 mm or less. For example, the wire diameter (or maximum cross-sectional dimension) of the woven mesh may be a wire diameter between 0.05 mm and 2 mm. In one embodiment, the porous barrier comprises a pleated material, such as a pleated woven mesh.

[0130] The porous barrier may be constructed of any suitable material. For example, when the porous barrier is constructed from a material with suitable oleophilic / oleophobic properties, it promotes further growth of air cavities and allows air cavities to pass through the barrier. In some embodiments, the porous barrier or a portion of the porous barrier is oleophobic. In some embodiments, at least one side of the porous barrier is oleophilic. In some embodiments, the porous barrier exhibits an oleophobic gradient, where the upstream side of the barrier is more oleophobic than the downstream side. The oleophobicity of the material may be expressed as an oleophobicity rating measured according to AATCC method 118. The oleophobicity rating of the porous barrier may be 1 or more, 1.5 or more, or 2 or more. The oil rating of the porous barrier may be 8 or less, or 6 or less. The porous barrier may be constructed of a composite material. The porous barrier may be a composite material of an oleophilic component and an oleophobic component. The oleophobic component has an oleophobicity rating of 1 or more.

[0131] The porous barrier may be constructed of a metal such as stainless steel. The porous barrier may be constructed from a woven or non-woven medium made from one or more of natural cellulose, regenerated cellulose (e.g., rayon), synthetic materials such as polyamide, polyester, polyethersulfone (PES), polypropylene (PP), polyethylene (PE), polytetrafluoroethylene (PTFE), polyvinylidene difluoride (PVDF), glass, ceramic, or carbon fibers. In an embodiment, the porous barrier comprises a woven metal mesh such as a stainless steel mesh. In an embodiment, the fibers (e.g., metal fibers) are coated. Polymeric or non-polymeric coatings such as resins may be used.

[0132] The porous barrier may be disposed in a cylindrical shape downstream of the growth medium. In some embodiments, the porous barrier at least partially surrounds (e.g., is nested with) the growth medium. In some embodiments, the growth medium at least partially surrounds the porous barrier. In some embodiments, the porous barrier is a planar or substantially planar sheet or other geometric configuration, such as a pleated sheet, or constructed from two or more planar or pleated sheets. The sheets or pleated sheets may be configured as a panel. The panel configuration may be disposed, for example, inside a tank.

[0133] The porous barrier may exhibit micro- and macro-texture. Micro-texture is used herein to refer to the surface texture of the barrier at the level of the individual fibers or wires that make up the barrier (e.g., variations smaller than 1 mm in size). Micro-texture is also referred to as surface roughness. Macro-texture is used herein to refer to the surface texture of the entire barrier (e.g., variations larger than 1 mm in size). The porous barrier may exhibit surface roughness. For example, the surface roughness of the porous barrier may be 1 nm or more, 10 nm or more, 25 nm or more, 50 nm or more, or 100 nm or more. The surface roughness of the porous barrier may be 1000 nm or less, 500 nm or less, or 200 nm or less. For example, the surface roughness of the porous barrier may be between 10 nm and 500 nm. In some embodiments, the porous barrier has little or no macro-texture, i.e., the porous barrier is "smooth", except that the porous barrier may be pleated.

[0134] Further characterizations of the porous barrier surface include skewness, kurtosis, and radius of curvature. The skewness of the fibers may be at least -10 or more, -8 or more, or -6 or more. The skewness of the fibers may be 6 or less, 8 or less, or 10 or less. The kurtosis of the fibers of the porous barrier may be -10 or more, -8 or more, or 6 or more. The kurtosis of the fibers of the porous barrier may be 6 or less, 8 or less, or 10 or less. A particular combination of surface roughness, skewness, and kurtosis provides favorable capture properties. For example, high roughness and kurtosis may be beneficial for capture. The radius of curvature of the fibers of the porous barrier may be up to 2 nm, up to 5 nm, up to 10 nm, up to 50 nm, up to 100 nm, or up to 500 nm.

[0135] The initial cleaning differential pressure of the porous barrier may be 0.01 psi (68.9 Pa) or less, 1 psi (6.89 kPa) or less, or 100 psi (689.5 kPa) or less, according to ISO 16889 practice at a suitable face velocity, for example 0.5 cm / sec.

[0043] Exemplary embodiments

[0136] Embodiment 1. A binder fiber and irregular rayon fibers distributed among the binder fibers. but not including non-fibrous resin.

[0137] Embodiment 2. Air permeability is 100 to 500 ft at 125 Pa. 3 / min·ft 2 The filter material according to any one of embodiments 1 and 3 to 12, wherein

[0138] Embodiment 3. The filter material of any one of embodiments 1-2 and 4-12, further comprising fibrillated rayon fibers.

[0139] Embodiment 4. The filter material of any one of embodiments 1-3 and 5-12, having a thickness of at least 0.25 mm.

[0140] Embodiment 5. Embodiment 13: The filter material according to any one of embodiments 1 to 4 and 6 to 12, which is up to 70% by weight of polyester fibers.

[0141] Embodiment 6. The filter material according to any one of embodiments 1 to 5 and 7 to 12, which is 30% by mass to 75% by mass of rayon fibers.

[0142] Embodiment 7. The filter material of any one of embodiments 1-6 and 8-12, wherein the filter material does not have a support layer.

[0143] Embodiment 8. The filter material of any one of embodiments 1-7 and 9-12, wherein the filter material is glass-free.

[0144] Embodiment 9. The filter material of any one of embodiments 1-8 and 10-12, comprising natural cellulose fibers.

[0145] Embodiment 10. The filter material of any one of embodiments 1-9 and 11-12, wherein the irregular rayon fibers are multilobal rayon fibers.

[0146] Embodiment 11. The filter material of any one of embodiments 1 to 10 and 12, wherein the linear mass density of the irregular rayon fibers is between 1 den and 7 den.

[0147] Embodiment 12. The filter material of any one of embodiments 1-11, wherein there are multiple low resistance flow paths through the filter material.

[0148] Embodiment 13. A filter assembly comprising: a particle filtration layer; a coalescence layer downstream of said particle filtration layer and bonded to said particle filtration layer; and a growth medium downstream of said coalescence layer, said growth medium comprising: irregular rayon fibers and binder fibers distributed among said irregular rayon fibers, but no non-fibrous resin.

[0149] Embodiment 14. The filter assembly of any one of embodiments 13 and 15-29, wherein the particle filtration layer, the coalescence layer and the growth medium are pleated and collectively define a tubular structure.

[0150] Embodiment 15. The filter assembly of any one of embodiments 13-14 and 16-29, wherein the particle filtration layer and the coalescing layer are pleated and collectively define a tubular structure with a central opening, and the growth medium forms a non-pleated tube within the central opening.

[0151] Embodiment 16. The filter assembly of any one of embodiments 13-15 and 17-29, wherein the particle filtration layer and the coalescing layer are pleated and collectively define a tubular structure with a central opening, and the growth medium is pleated and defines a tubular structure, and wherein a radial gap is defined between the growth medium and the coalescing layer.

[0152] Embodiment 17. The filter assembly of any one of embodiments 13-16 and 18-29, further comprising a porous barrier downstream of the growth medium.

[0153] Embodiment 18. The filter assembly of embodiment 17, wherein the porous barrier forms a tubular structure.

[0154] Embodiment 19. The air permeability is 100 to 500 ft at 125 Pa. 3 / min·ft 2 The filter assembly according to any one of embodiments 13 to 18 and 20 to 29,

[0155]

[0031] Embodiment 20. The filter assembly of any one of embodiments 13-19 and 21-29, wherein the growth medium further comprises fibrillated rayon fibers.

[0156]

[0031] Embodiment 21. The filter assembly of any one of embodiments 13-20 and 22-29, wherein the growth medium has a thickness of at least 0.4 mm.

[0157]

[0031] Embodiment 22. The filter assembly of any one of embodiments 13-21 and 23-29, wherein the growth medium is up to 70% by weight polyester fiber.

[0158] Embodiment 23. The filter assembly of any one of embodiments 13-22 and 24-29, wherein the growth medium is 40% to 75% by weight rayon fiber.

[0159]

[0041] Embodiment 24. The filter assembly of any one of embodiments 13-23 and 25-29, wherein the growth medium is free of a support layer.

[0160]

[0031] Embodiment 25. The filter assembly of any one of embodiments 13-24 and 26-29, wherein the growth medium does not include glass.

[0161]

[0031] Embodiment 26. The filter assembly of any one of embodiments 13-25 and 27-29, wherein the growth medium comprises natural cellulose fibers.

[0162] Embodiment 27. The filter assembly of any one of embodiments 13-26 and 28-29, wherein the irregular rayon fibers are multilobal rayon fibers.

[0163] Embodiment 28. The filter assembly of any one of embodiments 13 to 27 and 29, wherein the linear mass density of the irregular fibers is between 1 den and 7 den.

[0164] Embodiment 29. The filter assembly of any one of embodiments 13-28, wherein the growth medium defines a plurality of low resistance flow paths through the growth medium.

[0044]

[0165] It should also be noted that the term "configured," as used herein and in the appended claims, describes a system, apparatus, or other structure that is constructed to perform a particular task or adopt a particular configuration. The term "configured" can be used interchangeably with similar terms such as "deployed," "built," "manufactured," etc.

[0166] All publications and patent applications in this specification are indicative of the level of ordinary skill in the art to which this technology pertains. All publications and patent applications are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated by reference. In the event of any inconsistency between the disclosure of this application and the disclosure of any document incorporated by reference herein, the disclosure of this application shall control.

[0167] This application is intended to cover any adaptations or variations of the present subject matter. It is to be understood that the above description is intended to be illustrative, and not limiting, and that the claims are not limited to the exemplary embodiments described herein.

Claims

1. Binder fibers, and irregular rayon fibers distributed among the binder fibers; but not including non-fibrous resin.

2. Air permeability: 100-500 ft at 125 Pa ３ / min·ft ２ 2. The filter material of claim 1, wherein:

3. 3. The filter material of claim 1 or 2, further comprising fibrillated rayon fibers.

4. A filter material as described in claim 1 or 2, wherein the filter material is up to 70% by mass polyester fiber.

5. A filter material as described in claim 1 or 2, wherein the filter material is 30% to 75% by mass of rayon fiber.

6. The filter material described in claim 1 or 2, wherein the filter material does not have a support layer.

7. A filter material as described in claim 1 or 2, wherein the filter material does not contain glass.

8. The filter material described in claim 1 or 2, wherein the filter material contains natural cellulose fibers.

9. A filter material as described in claim 1 or 2, wherein the irregular rayon fibers are multilobal rayon fibers.

10. particle filtration layer, a coalescing layer downstream of the particle filtration layer and coupled to the particle filtration layer; a growth medium downstream of the coalescence layer comprising: Irregular rayon fibers, and binder fibers distributed among the irregular rayon fibers; but not including non-fibrous resin, growing medium a filter assembly.

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