Composite media for fuel flow

Abstract

To provide an improved filter medium for filtering particles and coalescing entrained water from a fuel stream throughout the useful life of the media. [Solution] A filter medium for use in fuel-water separation has a particle filtration layer and a coalescing layer downstream of and connected to the particle filtration layer. The particle filtration layer consists essentially of binder fibers and media fibers. The coalescing layer has at least 70% by weight glass fibers. In another embodiment, a filter medium for liquid fuels has a particle filtration layer and a coalescing layer downstream of the particle filtration layer. The particle filtration layer has binder fibers and media fibers and is substantially free of meltblown material. The ratio of the air permeability of the particle filtration layer to the air permeability of the coalescing layer ranges from about 3:1 to about 15:1.

Description

[Technical field]

[0001] This application was filed on June 23, 2016 as a PCT international patent application in the name of DONALDSON COMPANY, INC., a U.S. company, applicant designating all countries, and Aflal Rahmathullah, a citizen of India; Bradly Hauser, a U.S. citizen; Vijay Kapoor, a U.S. citizen; Mike J. Madsen, a U.S. citizen; Derek O. Jones, a U.S. citizen; and Charles Christ, a U.S. citizen, inventor designating all countries, and claims priority to U.S. Application No. 62 / 185,505, filed on June 26, 2015, the contents of which are incorporated herein by reference in their entirety.

[0002] FIELD OF THE ART The present technology relates generally to filtration media, and more particularly to coalescing and particulate filtration media for fuel streams. [Background technology]

[0003] Filtration of liquid fuels used in internal combustion engines is often essential for proper engine performance. For example, various diesel engines currently use fuel filtration media that target water and particulates that may be found in diesel fuel. Removal of such water and particulates is necessary to provide favorable engine performance as well as to protect engine components from damage. Free water present in the fuel as a separate phase can be of significant concern as it causes a variety of problems, including cavitation and corrosion, and damage to engine components by promoting microbial growth. Free water is different from dissolved water, which exists as a continuous phase and poses little concern for engine performance. Free water can be suspended as droplets of various sizes that can be classified as coarse and / or emulsified water. Coarse water generally refers to water droplets less than 60 microns in diameter, and emulsified water generally refers to water droplets greater than 60 microns in diameter. Some existing fuel filtration techniques attempt to cause free water entrained in the fuel to coalesce into larger droplets, thereby making it easier to separate the water from the fuel, but some commonly used fuel additives can stabilize the water droplets, making the free water difficult to coalesce. Summary of the Invention [Problem to be solved by the invention]

[0004] Particulate contaminants can cause serious engine performance problems and can also result in damage to the engine. Particulate contaminants can include hard particle debris such as dust and dirt, as well as fuel contaminants (FCPs) including fuel degradants (FDPs), waxes, asphaltenes, sterol glucosides, steryl glucosides and sterol glycosides. To further complicate the problem, particulate contaminants interfere with the ability of the coalescing media to effectively coalesce free water. Some techniques have attempted to solve this problem by using a media with an upstream particle filtration layer before the coalescing media layer, but the effectiveness of the coalescing layer is generally limited to the life of the particle filtration layer. As such, improved filtration media for filtering particles from the fuel stream and coalescing entrained water throughout the useful life of the media are desirable. [Means for solving the problem]

[0005] The technology disclosed herein generally relates to a filter medium for use in fuel-water separation having a particle filtration layer and a coalescing layer downstream of and connected to the particle filtration layer. The particle filtration layer is substantially composed of binder fibers and media fibers. The coalescing layer has at least 70% by weight glass fibers. In some exemplary embodiments, a filter medium for liquid fuels has a particle filtration layer and a coalescing layer downstream of the particle filtration layer. The particle filtration layer has binder fibers and media fibers, and is substantially free of meltblown materials. The ratio of the air permeability of the particle filtration layer to the air permeability of the coalescing layer ranges from about 3:1 to about 15:1.

[0006] This Summary is an overview of some of the teachings of the present application and is not intended as an exclusive or exhaustive treatment of the present subject matter. Further details are found in the detailed description and appended claims. Other aspects will be apparent to those skilled in the art upon reading and understanding the following detailed description and viewing the drawings that form a part thereof. Each of these is not to be construed in a limiting sense.

[0007] The examples may be more fully understood in connection with the following drawings. [Brief description of the drawings]

[0008]

Figure 1

Figure 2

[0009] While the embodiments herein are susceptible to various modifications and alterations, the characteristics of which are illustrated by the examples and drawings and will be described in detail hereinafter. It should be understood, however, that the scope of the invention is not limited to the particular examples described. On the contrary, the invention is intended to cover modifications, equivalents and alterations within the spirit and scope of the present specification.

[0010] FIG. 1 illustrates an example filtration medium 100 consistent with the technology disclosed herein. The filtration medium 100 is generally configured for use in fuel-water separation. The filtration medium 100 is configured for use for filtering particles from a fuel, in various embodiments. The filtration medium 100 is generally configured to filter out particulates from a fuel stream and to coalesce free water. The filtration medium 100 generally includes a particulate filtration layer 110, a coalescing layer 120 downstream of the particulate filtration layer 110, and a support layer 130 downstream of the coalescing layer 120.

[0011] The particle filtration layer 110, in various embodiments, is substantially composed of binder fibers and media fibers. The terms "substantially composed" or "substantially comprising" are used herein to mean that the material in question is at least 95% by weight of the particular component. In various embodiments, the particle filtration layer 110 is substantially free of meltblown materials. The particle filtration layer can be constructed, for example, as disclosed in U.S. Patent Application Publication No. 2012 / 0234748, filed March 16, 2012, or in another example, U.S. Patent No. 7,314,497, filed January 1, 2008, or in another example, U.S. Patent No. 9,056,268, filed June 16, 2015, each of which is incorporated herein by reference.

[0012] Medium Fiber Media fibers are those fibers that provide the media with its primary filtration properties, such as adjustable pore size, permeability, efficiency, etc. Media fibers can be, for example, glass fibers, carbon fibers, ceramic fibers, polyester, or cellulose. In some exemplary implementations of the particle filtration layer of the present invention, a fairly high proportion of glass fibers can be used. The glass fibers control the pore size and cooperate with other fibers in the media to provide the media with sufficient flow rate, high capacity, sufficient efficiency, and high wet strength.

[0013] The term glass fiber "source" refers to glass fiber compositions available as separate raw materials and characterized by average diameter and aspect ratio. Suitable media include types of glasses known by designations such as A, C, D, E, Zero Boron E, ECR, AR, R, S, S-2, N, etc., and generally any glass that can be made into fibers, either by drawing methods used to make reinforcing fibers or by spinning methods used to make insulating fibers. Such fibers are typically used with diameters of about 0.1 to 10 micrometers and aspect ratios (length divided by diameter) of about 10 to 10,000. Such commercially available fibers are characterized by sizing by application of a sizing agent. In general, suitable glass fibers should have an average diameter of less than 15 microns, more desirably less than 10 microns, and preferably less than 5 microns. Commercial sources of suitable glass materials include: Lauscha International, Evanite, Johns Manville, Owen Corning, and others.

[0014] In addition to glass fibers, alternative fibers suitable in some implementations for the media fibers include carbon fibers, cellulose fibers, and / or polyester fibers. In some embodiments, the media fibers are staple fibers. Generally, suitable carbon fibers should have an average diameter of less than 25 microns, more desirably less than 15 microns, and preferably less than 10 microns. Commercial sources of suitable carbon materials include Unitika, Kynol, and the like.

[0015] In embodiments, the particle filtration layer includes glass fibers in an amount corresponding to about 10% to 90% by weight of the total solids content of the particle filtration layer, or about 20% to 80% by weight of the total solids content of the particle filtration layer, or about 25% to 75% by weight of the total solids content of the particle filtration layer, or about 50% by weight of the total solids content of the particle filtration layer. In some embodiments, a blend of more than one glass fiber source is used, the blend of more than one glass fiber source being used to make up the total weight percentage of glass fibers in the particle filtration layer. In some such embodiments, the blend of glass fiber sources is selected to adjust the permeability of the particle filtration layer. For example, in some embodiments, the permeability of the particle filtration layer pack is increased by combining in various ratios (e.g., blends of two or more) more than one of glass fiber sources having an average fiber diameter of about 0.3-0.5 micrometers, glass fiber having an average fiber diameter of about 1-2 micrometers, glass fiber having an average fiber diameter of about 3-6 micrometers, glass fiber having an average fiber diameter of about 6-10 micrometers, and glass fiber having an average fiber diameter of about 10-100 micrometers. In some such embodiments, the blend of glass fibers is selected to tailor the pore size, thereby providing a specified permeability for the particle filtration layer.

[0016] Binder Fiber Binder fibers are generally configured to provide support for the media fibers and to impart improved handleability, strength, and compression resistance to the media fibers, and in certain implementations, the binder fibers also improve processability during formation of the furnish, sheet or layer formation, and downstream processing, including calibrating, drying, chopping, and forming filter elements.

[0017] The binder fiber may be, for example, a bicomponent fiber. As used herein, "bicomponent fiber" refers to a fiber formed from a thermoplastic material having at least one fiber portion with a melting point and a second thermoplastic portion with a lower melting point. The physical configuration of these fiber portions is typically a side-by-side or core-sheath type structure. In a side-by-side type structure, two types of resins are typically extruded in a form bonded in a side-by-side structure. Other useful forms include multi-lobed bicomponent fibers having lobes at the ends of the fiber formed from a polymer with a lower melting point than the rest of the fiber.

[0018] The use of bicomponent fibers allows for the formation of particulate filtration layers without the use of a separate resin binder or with a minimal amount of resin binder, thereby significantly reducing or preventing film formation by the binder resin and preventing loss of uniformity of the media or element due to migration of the resin to specific locations in the media layer. The use of bicomponent fibers allows for reduced compaction, improved solidity, and increased tensile strength of the filtration media, as well as improved utility of media fibers such as glass fibers and other submicron fibrous materials added to the media layer or filter element.

[0019] By combining media fibers and binder fibers in various ratios, a relatively high strength material is formed that has a fairly high filtration capacity, permeability, and filtration life. This type of media can be made with optional secondary fibers and other additive materials. By combining these components, a high strength material is formed that has a fairly high flow capacity, permeability, and high strength.

[0020] Various combinations of polymers for the bicomponent fibers may be used, but it is generally important that the first polymer component melts at a temperature lower than the melting temperature of the second polymer component, typically below 205°C. Furthermore, the bicomponent fibers are typically thoroughly mixed together with the media fibers (such as glass fibers) so that they are uniformly dispersed. Melting the first polymer component of the bicomponent fiber is necessary to allow the bicomponent fiber to form a cohesive skeletal structure that, upon cooling, captures and bonds many of the media fibers as well as other bicomponent fibers. In a core-sheath structure, a low melting point (e.g., about 80-205°C) thermoplastic resin is typically extruded around a fiber of a higher melting point (e.g., about 120-260°C) material.

[0021] In use, bicomponent fibers typically have a fiber diameter of about 5 to 50 micrometers, often about 10 to 20 micrometers, and typically have a fiber configuration with a total length of 0.1 to 20 millimeters, often about 0.2 to about 15 millimeters in length. Fibers of this type can be made from a variety of thermoplastic materials, such as polyolefins (polyethylene, polypropylene, etc.), polyesters (polyethylene terephthalate, polybutylene terephthalate, polycyclohexylene dimethylene terephthalate, etc.), nylons (nylon 6, nylon 6,6, nylon 6,12, etc.).

[0022] Bicomponent fibers are useful in forming mechanically stable, yet strong and permeable, filtration media that can withstand the mechanical stresses of debris-laden air passing through them at high velocities, retain debris collection during use, and withstand repeated wash-dry cycles between loadings. Bicomponent fibers useful in current technology are core / shell (or sheathed), side-by-side, islands-in-the-sea, or multilobal. Bicomponent fibers are composed of at least two thermoplastic materials with different melting points. In some embodiments, thermoplastic polymers useful for forming either the core or sheath of bicomponent fibers useful in particle filtration layers include polyolefins, such as polyethylene, polypropylene, polybutylene, poly-α-octene, and copolymers thereof (including linear low density, low density, high density, extra high density, and other named forms and compositions); polytetrahaloethylenes, such as polytetrafluoroethylene, polychlorotrifluoroethylene; polyesters, such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate; polyvinyl acetate, polyvinyl alcohol, and copolymers thereof; polyvinyl halides, such as polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride, and the like. polyacetals such as polyvinyl butyral, acrylic resins (polyacrylates) such as polymethacrylic acid esters and polymethyl methacrylate esters, and copolymers thereof such as copolymers of acrylic acid and salts thereof; polyamides such as nylon 6, nylon 66, nylon 6,10, nylon 46, and copolymers thereof; polystyrene and copolymers thereof; polyurethanes; polyureas; cellulosic resins, i.e., cellulose nitrate, cellulose acetate, cellulose acetate butyrate, ethyl cellulose, and the like; and copolymers of any of the above materials, such as ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, styrene-butadiene block copolymers, KRATON® rubber, and the like.

[0023] In an embodiment, a polyolefin / polyester sheath / core bicomponent fiber is used, with the polyolefin sheath melting at a lower temperature than the polyester core. In another embodiment, the core and sheath are made of two polyolefins, or two polyesters, two vinyl polyhalides, two vinylidene polyhalides, two polyamide polymers, or any other two chemically similar or identical polymers, which may have lower or higher melting or softening points depending on their composition (e.g., the specific monomer composition of the mixture used to synthesize the polymer or the blockiness of the monomer concentration in the copolymer), molecular weight, morphology (e.g., degree of branching, side chain crystallinity, etc.), etc.

[0024] In some embodiments, the low melting component of the bicomponent fiber is used as the sheath in a core / sheath configuration (or the shell in a core / shell configuration), as a leaf in a multilobal configuration, as an "island" in an islands-in-the-sea configuration, or as one side in a side-by-side configuration. The low melting component provides fusibility to the filtration media pack formed therewith, where the wet or airlaid nonwoven web is heated to a temperature above the melting point or glass transition temperature of the low melting component and below the melting point or glass transition temperature of the high melting component. In embodiments, fusion is achieved by contacting the molten or softened fiber component with other bicomponent fibers as well as any other fibers and additives within the formed wet or airlaid particulate filtration layer.

[0025] In such embodiments, when the temperature is then reduced below the intended end use temperature, at least a portion of the bicomponent fibers are fused to the sheath (or leaf or side) while substantially maintaining the properties imparted to the nonwoven by the airlaid or wet-laid process used to form the particle filtration layer, such as loft, permeability, porosity, basis weight, thickness, etc. These nonwoven properties are maintained because the higher melting core or side of the bicomponent fibers maintains its fibrous form during fusion. Additionally, fusion of the bicomponent fibers imparts desirable properties such as reduced compression and increased tensile strength, and further, fusion of the bicomponent fibers improves the availability and retention of glass fibers and other secondary fibers and / or additives in the particle filtration layer.

[0026] In some implementations, a core / sheath bicomponent fiber known as Advansa 271P, available from EI DuPont Nemours (Wilmington DE), is useful for forming both high-loft and low-loft filtration materials useful for particle filtration layers. Other useful bicomponent fibers include the T-200 series, which are concentric core / sheath fibers available from Fiber Innovation Technology, Inc. (Johnson City, TN); Kuraray N720 available from Engineered Fibers Technology, LLC (Shelton, CT); Nichimen 4080 available from Nichimen America Inc. (New York, NY); and similar materials. All of these fibers exhibit the fusible properties described above.

[0027] In some embodiments, the particle filtration layer comprises about 50% by weight Advansa 271P bicomponent fiber (available from EI DuPont Nemours, Wilmington Del.) and about 50% by weight Lauscha B50 glass microfiber (available from Lauscha Fiber Intl., Summerville, S.C.). The particle filtration layer is formed by a wet-laid or paper-laying process and has a mass of about 60 g / m 2~70g / m 2 The resulting composite has a basis weight of 0.02 mm to 0.06 mm, a layer thickness of 0.5 mm to 0.65 mm at 0.125 psi, a compressibility of 15% to 20% at 0.125 psi to 1.5 psi, and a solidity of 6% to 7% at 0.125 psi.

[0028] Particle filtration layer characteristics The performance characteristics of the particle filtration layer are influenced by tailoring the attributes of the particle filtration layer's fibers regarding size, pore structure, solidity, and compressibility. In general, using a medium with a relatively low solidity and low compressibility, while at the same time having a relatively small mean flow pore size but a relatively large maximum flow pore size, provides an exemplary media configuration that can remove particles without premature clogging. In some embodiments, the particle filtration layer is hydrophilic in air, meaning that a water droplet in air has a contact angle with the surface of the filtration layer of less than 90 degrees, as measured using a standard contact angle measuring device, such as a First Ten Angstroms contact angle gauge. The hydrophilicity of the particle filtration layer 110 can be distinguished from conventional meltblown materials that can be used for particle filtration in fuels, which tend to be hydrophobic in air. "Hydrophobic in air" generally means that a water droplet in air has a contact angle with the surface of the medium of greater than 90 degrees.

[0029] Generally, the media fibers have a smaller diameter than the binder fibers. In exemplary embodiments, the media fibers have an average diameter of less than 5 microns, while the binder fibers have an average diameter of greater than 5 microns. More typically, the media fibers will have an average diameter of 0.1 to 20 microns, and sometimes 0.1 to 15 microns. In some implementations, the media fibers will have an average diameter of 0.4 to 12 microns, and in some implementations, 0.4 to 6.5 microns. It is often desirable for the media fibers to have an average diameter of less than 10 microns, less than 7.5 microns, less than 6.5 microns, and less than 5 microns. The binder fibers will typically have a diameter of 5 to 40 microns, more typically 7 to 20 microns, and often 10 to 14 microns. It is noted that both the media and binder fibers can vary in diameter. In some cases, the diameter of the fibers will vary along their length, but more commonly, fibers of different diameters will be incorporated. It will be understood that the diameter of the fibers as used herein is based on the average fiber diameter of the fibers present in the media.

[0030] A further characteristic of particulate filtration layers is that they typically have a relatively low solidity. As used herein, solidity is the volume of solid fibers divided by the total volume of the subject filtration media, and is usually expressed as a percentage. In typical implementations, particulate filtration layers have a solidity of less than 15 percent, more typically less than 12 percent, and more often less than 10 percent. In certain embodiments, the solidity is less than 9 percent, less than 8 percent, or less than 7 percent. Particulate filtration layers generally have a solidity of less than about 45 cfm / ft 2 ~about 200cfm / ft 2 The air permeability, or Frazier permeability, ranges from 0.5 inches of water pressure drop to 0.5 inches of air (ft 2 ). 3 -min -1 -ft -2 or ft-min -1Generally, permeability, as the term is used, 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.

[0031] A further feature of particle filtration layers is their relatively low compressibility, especially given the solidity of the media. Compressibility is the resistance (i.e.) to compression or deformation in the direction of fluid passing through the media. A suitable test for compressing media is a compression force versus displacement test, in which a load is applied to a stack of media to determine the percentage compressed. An example of such a test is as follows: A 2.54 cm diameter probe and a 5 kg load cell are used to compress a stack of media to a total thickness of 25 mm. The test was performed at a speed of 1 mm / sec, starting at a distance of 30 mm from the bottom, and with a data trigger of 0.5 g. The final load target is 4,800 g. Media samples can be as large as a 2.22 cm diameter circle, and oriented to form a stack of media samples directly under the test probe. The pressure applied to the media in such an implementation is approximately 1.24 kg / cm 2 A sufficient number of stacked samples should be used to achieve a total thickness of 25 mm, so the total number of samples will vary depending on the particular thickness of the media material being tested. The data is analyzed based on the following formula: Compression ratio (percent) = x / t1 (where t1 is the thickness of the stack from the bottom when the load is 0.5 grams, t2 is the thickness of the stack from the bottom when the load is 4,800 grams, and x is equal to the distance the probe travels during the test, which is the distance t1-t2.) Suitable equipment for performing this test includes, for example, a TA.XT2i Texture Analyzer from Stable Micro Systems using Texture Expert Exceed software (version 2.64).

[0032] The compressive strength of the particle filtration layer must be sufficient to maintain the thickness of the material, thereby maintaining its pore structure, and thus its filtration flow rate and particulate removal performance. In some embodiments, the compressive strength of the particle filtration layer is 1.24 kg / cm 2 In another embodiment, the compressibility of the particulate filtration layer is less than 40 percent under a pressure of 1.24 kg / cm. 2 Less than 30 percent under pressure of 1.24 kg / cm 2 Less than 20 percent under pressure of 1.24 kg / cm 2 10%. Furthermore, the compressibility of the particulate filtration layer divided by the solidity is often less than 4, more often less than 3, and can be less than 2, and in some implementations is less than 1. For example, in an implementation with a compressibility of 20 percent and a solidity of 10 percent, this number is 2.0.

[0033] Further resin and fibers in the particle filtration layer A non-fiber binder resin can be used to help bind the media fibers and optionally the binder fibers into a mechanically stable particle filtration layer. This type of thermoplastic binder resin material can be used as a dry powder or as a solvent-based material, but is typically an aqueous dispersion of a thermoplastic vinyl resin. A non-fiber resin-based binder component is not necessary for the purpose of obtaining sufficient strength in the particle filtration layer, but it can be used.

[0034] Non-fiber binder resins include vinyl acetate materials, vinyl chloride resins, polyvinyl alcohol resins, polyvinyl acetate resins, polyvinyl acetyl resins, acrylic resins, methacrylic resins, polyamide resins, polyethylene vinyl acetate copolymer resins, thermosetting resins (urea phenol, urea formaldehyde, melamine, epoxy, polyurethane, curable unsaturated polyester resins, polyaromatic resins, resorcinol resins, similar elastomeric resins, and the like).

[0035] Suitable materials for the water-soluble or water-dispersible binder polymer are generally water-soluble or water-dispersible thermosetting resins such as acrylics, methacrylics, polyamides, epoxy resins, phenolic resins, polyureas, polyurethanes, melamine formaldehyde resins, polyesters, and alkyds, specifically water-soluble acrylics, methacrylics, and polyamides. Such liquid binders are typically dispersions of platelets that coat the fibers and promote adhesion between the fibers in the final nonwoven substrate. Sufficient resin is added to the furnish to completely coat the fibers without creating a membrane that blocks the pores formed in the sheet, media, or filter material. The resin can be added to the furnish or applied to the media after formation.

[0036] The latex binder used to bond the three-dimensional nonwoven fibrous webs together in each nonwoven layer or as an additional adhesive can be selected from a variety of latex-type adhesives known in the art. Those skilled in the art can select the specific latex-type adhesive depending on the type of cellulosic fibers to be bonded. The latex-type adhesive can be applied by known techniques such as spraying or foaming. Typically, latex-type adhesives with a solids content of 15-25% are used. The dispersion can be made by dispersing the fibers and then adding the binder material or dispersing the binder material and then adding the fibers. The dispersion can also be made by mixing a dispersion of fibers with a dispersion of binder material. The total concentration of fibers in the dispersion can range from 0.01 to 5 or 0.005 to 2 weight percent based on the total weight of the dispersion. The concentration of binder material in the dispersion can range from 10 to 50 weight percent based on the total weight of the fibers.

[0037] The particle filtration layer may also include second fibers, which may be made from any of a number of hydrophilic, hydrophobic, oleophilic, and oleophobic fibers. These fibers cooperate with glass (or other media) and bicomponent fibers to form a mechanically stable, yet strong and permeable filter material that can withstand the mechanical stresses of the fluid material passing through it and retain the captured particulates during use. The second fibers are typically monocomponent fibers, which may range in diameter from about 0.1 to about 50 micrometers, and may be made from a variety of materials. One type of second fiber is a binder fiber, which cooperates with other components to bind the material into a sheet. Another type of second fiber is a structural fiber, which cooperates with other components to increase the tensile and breaking strength of the material in the dry and wet states. Additionally, binder fibers may include fibers made from polymers such as polyvinyl chloride and polyvinyl alcohol. Second fibers may also include inorganic fibers, such as carbon / graphite fibers, metal fibers, ceramic fibers, and combinations thereof.

[0038] The second thermoplastic fiber may be, but is not limited to, polyester fibers, polyamide fibers, polypropylene fibers, copolyetherester fibers, polyethylene terephthalate fibers, polybutylene terephthalate fibers, polyetherketoneketone (PEKK) fibers, polyetheretherketone (PEEK) fibers, liquid crystal polymer (LCP) fibers, and mixtures thereof. Polyamide fibers include, but are not limited to, nylon 6, 66, 11, 12, 612, and heat-resistant "nylons" (such as nylon 46), cellulosic fibers, polyvinyl acetate, polyvinyl alcohol fibers (including polyvinyl alcohols of various degrees of hydrolysis, such as 88% hydrolyzed, 95% hydrolyzed, 98% hydrolyzed, and 99.5% hydrolyzed polymers), thermoplastics such as cotton, viscose rayon, polyester, polypropylene, polyethylene, polyvinyl acetate, polylactic acid, and other common types of fibers. Thermoplastic fibers are typically very fine (diameter about 0.5-20 denier), short staple (length about 0.1-5 cm) fibers that may contain pre-blended conventional additives (antioxidants, stabilizers, lubricants, toughening agents, etc.). Additionally, thermoplastic fibers may be surface treated with dispersing aids. Preferred thermoplastic fibers are polyamide and polyethylene terephthalate fibers, with polyethylene terephthalate fibers being most preferred.

[0039] Manufacturing of particle filtration layers In a particular embodiment of the particle filtration layer construction, a fiber mat is formed using either wet or dry processing. The mat is heated to melt the thermoplastic material and bond the fibers internally to form the media. Bicomponent fibers can be fused to the fibers to obtain a mechanically stable media. The bicomponent fibers have a thermally bonded sheath on the outside, which bonds the bicomponent fibers to other fibers within the media layer.

[0040] Particle filtration layers are typically made using papermaking methods. However, media can also be made using airlaid methods using similar ingredients suitable for airlaid processing. Machines used to make wet sheets include handsheet equipment, Fourdrinier paper machines, cylinder paper machines, tilt paper machines, combination paper machines, and other machines that can collect appropriately mixed paper, form one or more layers of raw papermaking ingredients, and remove aqueous fluid components to form a wet sheet.

[0041] In an exemplary wet processing, the media is made from an aqueous papermaking stock that includes an aqueous media dispersion of fibrous material. The aqueous liquid of the dispersion is usually water, but can include various other materials such as pH adjusters, surfactants, defoamers, fire retardants, viscosity modifiers, media treatments, colorants, etc. Typically, the dispersion is conveyed through a screen or other porous support, which allows the aqueous liquid to drain from the dispersion while retaining the dispersed solids, to produce a wet paper composition. Once the wet composition is formed on the support, it is typically further dehydrated under vacuum or other applied pressure, and then dried by evaporating the remaining liquid. After the liquid is removed, it is typically thermally bonded by melting a portion of the thermoplastic fibers, resin, or other parts of the formed material. The molten material bonds the components into layers.

[0042] A fiber slurry containing this material is typically formed into a relatively homogeneous fiber slurry by mixing. The fiber slurry is then subjected to a wet-laid papermaking process. Once the slurry is formed into a wet-laid sheet, the wet-laid sheet is then dried and cured or otherwise processed to form a permeable but substantially dry sheet, media, or filter. Once sufficiently dried and processed into a filtration medium, the sheet typically has a thickness of about 0.25 to 1.9 millimeters and a basis weight of about 20 to 200 or 30 to 150 g m -2Typically, for commercial scale processing, the bicomponent mat is processed using papermaking machines such as commercially available Fourdrinier, Cylinder, Stevens Former, Rotoformer, Inver Former, Venti Former, and tilted delta former machines.

[0043] In some implementations, an inclined delta former machine is utilized. The bicomponent mat can be made by forming a slurry of pulp and glass fibers and mixing the slurry, for example, in a mixing tank. The amount of water used in the 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 and dewatered by suction or vacuum to form a bicomponent nonwoven web. The web can then be coated with a binder using conventional means, for example, a flood and extract method, and passed through a dryer section to dry the mat, cure the binder, and thermally bond the sheet, media, or filter. The resulting mat can be collected on a large roll and further processed to be laminated with a second media material (such as a layer of cellulose media) or formed into a filter element.

[0044] Particle filtration layer 110 can be comprised of multiple media layers in various embodiments. Generally, each media layer of particle filtration layer 110 will be configured as described herein. Such an embodiment is shown in FIG. 2, which is described in more detail below.

[0045] combined layer Returning to FIG. 1 , the coalescing layer 120 is located downstream of and coupled to the particulate filtration layer 110. The coalescing layer 120 is generally configured to coalesce free water in the fuel stream passing therethrough. The particulate filtration layer 110 is generally configured to trap particulate contamination from the fuel stream, thereby preventing the trapped particles from interfering with the coalescing function of the coalescing layer 120. However, in some embodiments, the coalescing layer can also be configured to filter particulates in the fuel stream. The coalescing layer 120 can have a variety of shapes.

[0046] The coalescing layer 120 can have an average fiber diameter ranging from about 0.3 μm to about 10 μm, or from about 0.69 μm to about 7.5 μm. The coalescing layer 120 can generally have a thickness ranging from about 0.3 mm to about 1.0 mm when measured at 8 psi. In some embodiments, the coalescing layer 120 can have a thickness ranging from about 0.4 mm to about 0.7 mm when measured at 8 psi. The coalescing layer 120 can generally have a weight per unit area of ​​about 50 g / m 2 ~Approx. 150g / m 2 , or about 80 g / m 2 ~Approx. 115g / m 2 The coalescing layer 120 can have a basis weight in the range of about 3 cfm. The coalescing layer 120 can have a basis weight higher than the basis weight of the particulate filtration layer 110. The coalescing layer 120 generally has an air permeability lower than the air permeability of the particulate filtration layer 110. In some embodiments, the coalescing layer 120 has an air permeability of about 3 cfm. / ft 2 ~about 70cfm / ft 2 In some particular embodiments, the coalescing layer 120 has an air permeability in the range of 10 to 40 cfm. / ft 2 In some embodiments, the coalescing layer 120 can be multiple layers of adjacent coalescing material, such as in the embodiment described below with reference to FIG.

[0047] In various embodiments, the coalescing layer 120 is a wet media. The coalescing layer 120 is substantially composed of fibers, surface treatments, and binder materials, meaning that the coalescing layer 120 is at least 95% by weight of fibers, surface treatments, and binder materials. In some embodiments, the coalescing layer 120 is a nonwoven fiber mat coated with a surface treatment, and the fibers are bonded with a binder material. The surface treatment is generally configured to change the surface energy of the fibers therein, and the binder material is generally configured to bond the fibers of the coalescing layer 120.

[0048] The fibers of the coalescing layer 120 can be various types of fibers and combinations of fibers, and are generally nonwoven. The fibers of the coalescing layer 120 can be glass fibers, natural fibers, synthetic fibers, polymeric fibers, ceramic fibers, metal fibers, carbon fibers, and combinations thereof. Other types of fibers are certainly contemplated. In some embodiments, the coalescing layer 120 comprises glass fibers and polyester fibers. The fibers can be 50% to 95% by weight of the coalescing layer 120. In some embodiments, the coalescing layer 120 is at least 70% glass fibers by weight. In some embodiments, the coalescing layer 120 is at least 85% glass fibers by weight.

[0049] The surface treatment is generally configured to modify the surface properties of the fibers within the coalescence layer 120. The surface treatment can have a variety of shapes and compositions, and in some embodiments, the surface treatment is a compound containing fluorine. One example of a surface treatment that can be used on the fibers of the coalescence layer is a polytetrafluoroethylene dispersion. Some other examples of surface treatments are fluoroalkyl acrylate polymers, perfluoroalkyl methyl acrylate copolymers, fluorohydrocarbons, fluoroacrylate polymers, fluoroalkyl methacrylate polymers, perfluoroalkoxy polymers (PFA), fluorinated ethylene propylene (FEP). The surface treatment can range from 0.01% to 25% by weight of the coalescence layer 120. In some embodiments, the surface treatment can be 5% to 20% or 10% to 15% by weight of the coalescence layer 120.

[0050] The binder material is generally configured to bond the fibers in the coalescing layer 120. The binder material can be, by way of example, a polyacrylate or an epoxy. In some specific examples, the binder material is an acrylic latex binder. In some examples, the binder material is a styrene / acrylonitrile copolymer resin. The binder material can 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 oxidized acrylate, a polyvinyl alcohol, and combinations thereof. In an embodiment, the binder material can be a polymer modified to comprise one or more functional groups. For example, the polymer may be functionalized to include additional carboxylates. Coalescing layer 120 can be from about 3% to about 40% by weight binder material, alternatively from about 5% to about 25% by weight binder material, or from about 10% to about 20% by weight binder material.

[0051] Some embodiments of the technology disclosed herein, including those shown in Figures 1 and 2, have a support layer 130 disposed downstream of and coupled to the coalescing layer 120. The support layer 130 can be constructed from a variety of materials and combinations of materials, but is generally configured to provide structural support to the particle filtration layer 110 and the coalescing layer 120. In various embodiments, the support layer 130 is configured to at least allow water droplets to exit the filtration media 100 relatively intact and to prevent emulsification of the coalesced water from the coalescing layer 120.

[0052] In some embodiments, the support layer is a bicomponent fiber. In some such embodiments, the bicomponent fiber is a substantially continuous polyester fiber with a nylon sheath, such as Colback® supplied by Bonar Inc., based in Asheville, North Carolina. In some other embodiments, the support layer 130 is a cellulosic material. In some embodiments, the support layer 130 is a scrim, such as a nonwoven polyester scrim. In some embodiments, the polyester scrim is Reemay, supplied by Polymer Group, Inc., based in Charlotte, North Carolina. The support layer 130 can be a combination of materials, such as cellulose and polyester. In some embodiments, the support layer 130 is a wire mesh. Other materials are certainly contemplated for the support layer 130.

[0053] The support layer 130 may also have one or more binder materials. For example, in some embodiments, the support layer is saturated with a phenolic resin or any other type of binder. The support layer 130 may also be treated with one or more compositions to tailor the properties of the support layer 130. In some embodiments, the support layer 130 has a thickness of about 17 g / m 2 ~about 200g / m 2 The support layer 130 generally has a basis weight of 10 cfm. / ft 2~ approx. 1000 cfm / ft 2 In some embodiments, the support layer 130 has an air permeability of about 30 cfm. / ft 2 It has air permeability of .

[0054] It will be appreciated that the support layer 130 may include fibers having a diameter or cross-section larger than the average diameter of the media fibers in the particulate filtration layer 110 .

[0055] The coalescing layer 120 is connected to the particle filtration layer 110. The support layer 130 is connected to the coalescing layer 120. The phrase "connected" is intended to mean that the respective layers are fixed to one another. In some embodiments, the layers are fixed to one another by adhering to the filtration element or are not bonded. In some embodiments, the respective layers are laminated together. For example, in some embodiments, low temperature crystalline polymer powders are used to laminate the layers together to produce a composite media that can be easily manufactured into many different filtration element shapes. Other methods of laminating the media layers together, such as adhesive lamination or thermal bonding means, are also possible by use of web adhesives, hot melts, etc. In some embodiments, the layers are not bonded.

[0056] Consistent with the technology disclosed herein, filtration media 100 can have a variety of different shapes. In at least one embodiment, filtration media 100 does not include a meltblown material. filtration media 100 can have a mass of 100 g / m 2 ~500g / m 2 , 200g / m 2 ~400g / m 2 , or 250 g / m 2 ~350g / m 2 The filtration media 100 may have a basis weight of about 100 g / m2 or about 100 g / m2. The filtration media 100 may have a thickness in the range of 0.5 mm to 4 mm or 1 mm to 2 mm when measured at 1.5 psi. Generally, the air permeability of the coalesced layer 120 will be less than the air permeability of the particulate filtration layer 110.

[0057] The air permeabilities of the particle filtration layer 110 and the coalescing layer 120 are generally related. The ratio of the air permeability of the particle filtration layer 110 to the air permeability of the coalescing layer 120 will generally be from about 3:1 to about 15:1. In some instances where the ratio of the air permeability of the particle filtration layer 110 to the coalescing layer 120 is too high, the coalescing layer 120 will load with particulate matter relatively quickly and the coalescing layer 120 will tangle prematurely, thereby inhibiting proper coalescence. On the other hand, if the ratio of the air permeability of the particle filtration layer 110 to the coalescing layer 120 is too low, inadequate lifetime for particulate filtration will result.

[0058] The air permeability of the resulting filtration media 100 and each of the component layers can correspond to the size of the free water droplets that are coalesced from the fuel stream. If the coalescing free water droplets are characterized as coarse, the air permeability of the filtration media 100 can be relatively high. If the coalescing free water droplets are characterized as emulsified, the air permeability of the filtration media 100 can be relatively low. In some embodiments, the filtration media 100 can have an air permeability of 1 cfm / ft 2 ~50cfm / ft 2 In some embodiments, the filtration media 100 has a permeability in the range of 3 cfm / ft 2 ~20cfm / ft 2 In some embodiments, the filtration media 100 has a permeability in the range of 5 cfm / ft 2 ~10cfm / ft 2 It has a permeability in the range of

[0059] 2 illustrates another example of a filtration medium consistent with the technology disclosed herein. In this embodiment, the filtration medium 200 has an upstream particle filtration layer 212, a coalescing layer 220 downstream of the particle filtration layer 210, and a support layer 230 downstream of the coalescing layer 220. The particle filtration layer 210 has an upstream media layer 212 and a downstream media layer 214. In some embodiments, the upstream media layer 212 and the downstream media layer 214 can have different properties from each other, such as different pore sizes and pore size distributions. In general, the air permeability of the particle filtration layer 210 will be understood herein to refer to the overall resulting air permeability of its component layers 212, 214.

[0060] In this embodiment, the coalescing layer has two layers of coalescing material 222, 224, and in some embodiments there can be additional layers of coalescing material.

[0061] 2 shows an embodiment where there are multiple layers of coalescing layer 220 and multiple layers of particle filtration layer 210, it should be understood that in some embodiments where the particle filtration layer has multiple layers, there can also be a coalescing layer that is a single layer. Similarly, in some embodiments where there is a single layer in the coalescing layer, there can also be multiple layers in the particle filtration layer. It will be understood that in the technology described herein, there can also be multiple support layers. EXAMPLES

[0062] Test results Flat sheets of filtration media consistent with the technology disclosed herein were tested against comparative filtration media known in the art. In particular, example filtration media consistent with the technology disclosed herein were made of glass fibers and Two The particle filtration layer had an upstream particle filtration layer of component polyester binder fiber. The particle filtration layer was composed of two media layers, with the upstream media layer having a higher air permeability than the downstream media layer. The total air permeability of the particle filtration layer was about 120 cfm. / ft 2The comparative filter media had a particulate filtration layer of conventional meltblown polyester, which is widely considered to be optimized for particulate filtration for fuel filtration. The meltblown polyester had a particle filtration layer of about 25 cfm / ft 2 The example media (Sample B) and the comparative media (Sample A) both had identical coalesced and support layers. The coalesced layer had an air permeability of about 10 cfm. / ft 2 The media layers were microfine glass media bonded with an acrylic resin having an air permeability of 0.01%. The support layer had substantially continuous polyester fibers with a nylon sheath. The media layers were unbonded in both samples.

[0063] The coalescence capabilities of the comparative and example media were compared by challenging the media with a water-fuel emulsion (ultra-low sulfur diesel fuel) with an average water droplet size of 15 μm and then measuring the size of the water droplets exiting the media. Coalescence to achieve relatively larger water droplets is generally preferred because larger droplets sink the fuel stream more easily than smaller droplets. Droplet sizes were measured and are reported in terms of the following particle size distribution values: 3,10 , D 3,50 and D. 3,90 D 3,10 The value is the value at which 10% of the total volume of water in the fuel is D 3,10 represents the diameter defined by a water droplet having a droplet diameter smaller than the value D. 3,50 The value is that about 50% of the water volume is D 3,50 The diameter is smaller than the value of D and about 50% of the volume of water is 3,50 represents the mean droplet diameter defined by the water droplets having a diameter greater than the value of D. 3,90 The value is 90% of the total volume of water, D 3,90 represents the droplet size as defined by droplets having a diameter smaller than the value.

[0064] When clean, the comparative media (Sample A) and the example media (Sample B) performed relatively similarly, however, when loaded with dust, the example filtration media performed better than the comparative media in terms of both differential pressure and coalescence of water from the fuel.

[0065] To load the dust, a known amount of ISO media test dust was suspended in ultra-low sulfur diesel fuel and passed through each sample media. Each media was loaded with 100 mg of dust and the differential pressure across the media was measured. The differential pressure across the comparative media (Sample A') was twice that of the example media (Sample B'). Additionally, the D 3,10 The water droplets that were left behind were more than three times the diameter of the comparative media (Sample A'). Finally, the example media was loaded with more ISO media test dust until the differential pressure was nearly equal to that of the comparative media, which required 230 mg of dust (Sample B''), more than twice that of the comparative media (Sample A'). The diameter of the water droplets leaving Sample B'' was measured, and D 3,10 The values ​​were more than double those of the comparison medium (Sample A'). Table 1 below reflects the relevant data.

[0066] [Table 1]

[0067] D for dust loaded media 3,10 The D values ​​distinguish the performance of the example media (samples B' and B'') from the comparative media (sample A') because they demonstrate that a smaller volume of water remains emulsified in the fuel as smaller droplets when using the example media. 3,10 It also indicates that the drop rate of droplet size is lower than that of the comparative media. This test data demonstrates that media consistent with the technology disclosed herein will have higher dust retention capacity and therefore will have a relatively longer filter life than the comparative media. Additionally, and surprisingly, this test data also demonstrates that when the media exhibits the same pressure drop as the comparative media (and thus when the media "fouls" to the same extent), the coalescence performance of the example media remains particularly better than that of the comparative media.

[0068] It should be noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the" include the plural forms unless the content clearly dictates otherwise. Thus, for example, reference to a composition containing a "compound" includes a mixture of two or more compounds. It should also be noted that the term "or" is generally utilized in its "and / or" sense unless the content clearly dictates otherwise.

[0069] All publications and patent applications in this specification are indicative of the level of skill of those skilled 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.

[0070] The present technology has been described with reference to various specific and preferred embodiments and techniques, however, it should be understood that many variations and modifications may be made while remaining within the spirit and scope of the technology.

Claims

1. 1. A filter medium for use in fuel-water separation, comprising: A particle filtration layer comprising binder fibers and glass fibers, said binder fibers and said glass fibers being at least 95% by weight of said particle filtration layer, said particle filtration layer having a thickness of 1371.6 cm ３ / cm ２ ・min(45cfm / ft ２ a particulate filtration layer having an air permeability of from 6096 cm 3 / cm 2 ·min (200 cfm / ft 2 ); a coalescence layer downstream of and connected to the particle filtration layer, the coalescence layer comprising an acrylic resin and at least 90% by weight glass fiber and having a thickness of 304.8 cm ３ / cm ２ ・min(10cfm / ft ２ ) to 1219.2 cm 3 / cm 2 ·min (40 cfm / ft 2 ); a support layer downstream of the coalescing layer; A filtration medium, the filtration medium being configured to filter out particles and coalesce free water in a fuel stream.

2. 10. The filtration media of claim 1, wherein the compressibility of the particulate filtration layer divided by the solidity of the particulate filtration layer is less than 4.

3. The filtration medium of claim 1 , wherein the binder fibers comprise thermoplastic fibers.

4. 1. A filter medium for use in fuel-water separation, comprising: A first particle filtration layer comprising binder fibers and glass fibers, said binder fibers and said glass fibers being at least 95% by weight of said particle filtration layer, said particle filtration layer having a thickness of 1371.6 cm ３ / cm ２ ・min(45cfm / ft ２ ) to 6096 cm ３ / cm ２ ・min(200cfm / ft ２ a first particle filtration layer having an air permeability of up to a second particulate filtration layer downstream of the first particulate filtration layer; a coalescing layer downstream of the first particle filtration layer and coupled to the first particle filtration layer and the second particle filtration layer, the coalescing layer comprising an acrylic resin and at least 85% by weight glass fibers, at least 95% by weight of the glass fibers and the acrylic resin, and having a length of 304.8 cm ３ / cm ２ ・min(10cfm / ft ２ ) to 1219.2 cm ３ / cm ２ ・min(40cfm / ft ２ a coalescing layer having an air permeability of 0.69 μm to 7.5 μm and an average fiber diameter of 0.69 μm to 7.5 μm; a support layer downstream of the coalescing layer and the second particle filtration layer; A filtration medium, the filtration medium being configured to filter out particles and coalesce free water in a fuel stream.

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