Filter media, filter elements and filter methods

Abstract

A fibrous filtration medium is disclosed, the fibrous filtration medium comprising: a surface load filtration layer, the surface load filtration layer comprising fine fibers having an average diameter of less than 1 micron; a depth load filtration layer; and a support layer; wherein the layers are configured and arranged for placement in a gas stream with the surface load filtration layer being the most upstream layer.

Description

[0001] Continue to apply for data

[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 336,433, filed May 13, 2016, and U.S. Provisional Application No. 62 / 351,401, filed June 17, 2016, the disclosures of which are incorporated herein by reference in their entirety. Background Technology

[0003] Fluid flows (especially air and gas flows) often carry particulate matter. It is necessary to remove some or all of the particulate matter from fluid flows. For example, air intakes into motor vehicle cabins, air from computer disk drives, HVAC air, cleanroom ventilation air, air entering engines for vehicles or power generation equipment, gas flows directed to gas turbines, and air flows into various combustion furnaces typically contain particulate matter. In the case of cabin air filters, it is desirable to remove particulate matter for passenger comfort and / or for aesthetic purposes. As for air intake and gas intake flows into engines, gas turbines, and combustion furnaces, it is desirable to remove particulate matter because particulates can cause substantial damage to the internal operation of the various mechanisms involved. In other cases, production gases or exhaust gases from industrial processes or engines may contain particulate matter. It is typically desirable to remove significant amounts of particulate matter from these flows before releasing such gases into the atmosphere.

[0004] There is a growing need for increasingly efficient filters to achieve cleaner airflow or other gas flow. Low pressure is desirable, as it imposes less restriction on the flow of gas (e.g., air) resulting from high-efficiency filters. Additionally, longer lifespan is desirable to reduce maintenance and filter costs; however, a long lifespan is often a challenge for high-efficiency filters. Therefore, there is a persistent need for high-performance filters (i.e., high efficiency, low pressure drop, long lifespan filters). Summary of the Invention

[0005] This disclosure provides filter media and filter elements, which are particularly suitable for gas (e.g., air) filtration applications.

[0006] In one embodiment, a gas filter medium (e.g., an air filter medium) is provided, comprising: a surface-loaded filter layer comprising fine fibers having an average diameter of less than 1 micrometer; a depth-loaded layer; and a support layer. During use, the layers are configured and arranged for placement in a gas flow, wherein the surface-loaded filter layer is the upstream layer. That is, the layers are positioned relative to each other such that the surface-loaded filter layer is positioned as the first layer encountered by the gas (e.g., air) flow being filtered (i.e., the fine fiber filter layer is the upstream layer). In some embodiments, the filter medium disclosed herein is pulse-cleanable.

[0007] In another embodiment of this disclosure, a gas filtering element (e.g., an air filtering element) is provided, the gas filtering element including a housing and a filter medium as described herein.

[0008] In another embodiment of this disclosure, a method for filtering a gas (e.g., air) is provided, the method comprising guiding the gas through a filter medium or filter element as described herein.

[0009] In some embodiments, the depth-loaded filter layer includes a high-efficiency glass-containing filter layer, a melt-blown filter layer, or a combination thereof. A high-efficiency glass-containing filter layer may include glass fibers and multi-component bonded fibers. A high-efficiency melt-blown filter layer may include fibers having an average diameter of 0.5 micrometers to 10 micrometers.

[0010] In this document, "high efficiency" with respect to the filter layer disclosed herein means the ability to remove at least 55% (by quantity) of 0.4-micron DEHS particles at a rate of 4 feet per minute (ft / min or fpm) (i.e., 2 centimeters per second (cm / s)). For example, a filtration efficiency of at least 70% at 0.4 microns is considered "high efficiency". In some embodiments herein, high efficiency means removing at least 70%, at least 80%, at least 85%, at least 95%, at least 99.5%, at least 99.95%, or at least 99.995% of such particles at 4 ft / min (2 cm / s).

[0011] In this document, "high efficiency" for the composite filter media (which may be wrinkled or not) and / or filter elements (typically wrinkled and pleated) of this disclosure is defined as an efficiency of at least F9 according to EN779:2012. Furthermore, the "high efficiency" filter elements (typically wrinkled and pleated) of this disclosure are defined as having an efficiency of at least E10, or at least E11, or at least E12 according to EN1822:2009.

[0012] The term "meltblown fiber" refers to fibers formed by extruding molten thermoplastic material through multiple thin (typically circular) die capillaries as molten threads or filaments into a converging high-speed gas (e.g., air) stream. This stream thins the molten thermoplastic material into filaments, reducing their diameter to a level comparable to that of microfibers. These meltblown fibers are then carried by the high-speed gas stream and deposited onto a collection surface to form a randomly dispersed web of meltblown fibers. Meltblown fibers are typically microfibers, which can be continuous or discontinuous, typically with a diameter equal to or less than 20 micrometers (and typically 10 micrometers), and are generally self-bonded upon deposition onto the collection surface. The meltblown fibers used in this invention are preferably substantially continuous in length.

[0013] The term "multicomponent fiber" refers to a fiber formed from at least two polymers, which are extruded separately but rotated together to form a single fiber. As a specific example of a multicomponent fiber, a "bicomponent fiber" comprises two polymers arranged in substantially constant positions in different regions across the cross-section of the bicomponent fiber and extending continuously along its length. The configuration of such a bicomponent fiber can be, for example, a sheath / core configuration, where one polymer is surrounded by another, or it can be a side-by-side configuration or an "islands-in-the-sea" configuration. For bicomponent fibers, the polymers can be present in ratios of 75 / 25, 50 / 50, 25 / 75, or any other desired ratio. Conventional additives, such as pigments and surfactants, can be incorporated into one or both polymer streams or applied to the surface of the filament.

[0014] The term "polymer" includes, but is not limited to, homopolymers, copolymers (such as block copolymers, graft copolymers, random copolymers and alternating copolymers, terpolymers, etc.), and blends and modifications thereof. Furthermore, unless otherwise specifically limited, the term "polymer" shall include all possible geometries of the material. These geometries include, but are not limited to, isotactic, syndiotactic, and atactic symmetries. The term "copolymer" refers to a polymer comprising two or more different monomer units, thus including terpolymers, tetrpolymers, etc.

[0015] The terms “comprising” and “including” and their variations are not restrictive in their presence in the specification and claims. Such terms are to be understood as implicitly including the stated steps or elements or a group of steps or elements, but not excluding any other steps or elements or any other group of steps or elements. “Constitutes of” means including and limited to anything contained in the phrase “consisting of”. Therefore, the phrase “consisting of” indicates that the listed elements are necessary or mandatory, and other elements may be absent. “Substantially constitutes of” means including any element listed in the phrase, and limited to other elements that do not impede or contribute to the activity or effect specified for the listed elements in this disclosure. Therefore, the phrase “substantially constitutes of” indicates that the listed elements are necessary or mandatory, but other elements are optional and may or may not be present depending on whether they substantially affect the activity or effect of the listed elements.

[0016] The terms "preferred" and "ideally" refer to embodiments of this disclosure that may provide certain benefits in certain circumstances. However, other embodiments may also be preferred in the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are useless and is not intended to exclude other embodiments from the scope of this disclosure.

[0017] In this application, terms such as “a,” “an,” and “the” are not intended to refer to a singular entity only, but rather to include a general category of specific instances that may be used for illustration. The terms “a,” “an,” and “the” are used interchangeably with the term “at least one.”

[0018] The phrases “at least one of” and “comprise at least one of” that follow a list refer to any one of the items in the list and any combination of two or more items in the list.

[0019] As used herein, the term “or” is generally used in its usual sense, including “and / or”, unless the context clearly indicates otherwise. The term “and / or” means one or all of the listed elements, or a combination of any two or more of the listed elements.

[0020] Furthermore, in this document, it is assumed that all figures are modified by the term “about,” and preferably by the term “precisely.” As used herein in conjunction with the quantity being measured, the term “about” refers to the variation in the quantity being measured as would be expected by a person skilled in the art who would perform the measurement and apply a level of care commensurate with the purpose of the measurement and the precision of the measuring equipment used.

[0021] In addition, in this document, the description of a numerical range by endpoints includes all numbers falling within the range as well as the endpoints (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.). In this document, "up to" a certain number (e.g., up to 50) includes the number (e.g., 50).

[0022] The term "in the range" (and similar statements) includes the end values ​​of the stated range.

[0023] Throughout this specification, the terms "one embodiment," "an embodiment," or "some embodiments," etc., refer to specific features, configurations, compositions, or characteristics described in connection with the embodiment, which are included in at least one embodiment of the invention. Therefore, the appearance of such phrases in different places throughout this specification does not necessarily refer to the same embodiment of the invention. Furthermore, in one or more embodiments, specific features, configurations, compositions, or characteristics can be combined in any suitable manner.

[0024] The above overview of this disclosure is not intended to describe an embodiment or implementation of every disclosure. The following description illustrates illustrative embodiments in more detail. Throughout this application, guidance is provided by a list of examples that can be used in various combinations. In each example, the listed examples are intended only as representative groups and should not be construed as exclusive. Attached Figure Description

[0025] This disclosure can be understood more fully by referring to the following figures.

[0026] Figure 1 This is a cross-sectional view as part of an embodiment of the composite filter media disclosed herein.

[0027] Figure 2 This is a cross-sectional view of one embodiment of the composite filter media disclosed herein.

[0028] Figure 3 This is a cross-sectional view of one embodiment of the composite filter media disclosed herein.

[0029] Figure 4This is a perspective view of one embodiment of a filter element that can be used in an air intake system.

[0030] Figure 5 This is a perspective view of another embodiment of a filter medium having another element disclosed herein.

[0031] Figure 6 This is a top plan view of another filter element disclosed herein that can be used in an air intake system.

[0032] Figure 7 yes Figure 6 Front elevation view of the component.

[0033] Figure 8 yes Figure 7 Right elevation view of the filter element.

[0034] Figures 9 to 13 This is a schematic cross-sectional view of a further embodiment of the filter element.

[0035] Figure 14 This is a perspective view of another embodiment of the filter element.

[0036] Figure 15 This is a perspective view of another embodiment of a filter element having an oval structure. Detailed Implementation

[0037] This disclosure provides filter media and filter elements, which are particularly suitable for gas (e.g., air) filtration applications.

[0038] In one embodiment, the gas filter medium (e.g., air filter medium) includes: a surface-loaded filter layer comprising fine fibers having an average diameter of less than 1 micrometer; a depth-loaded filter layer; and a support layer.

[0039] During use, the layers are configured and arranged for placement in a gas flow, wherein the surface-loaded filter layer is the upstream layer. That is, the layers are positioned relative to each other such that the surface-loaded filter layer (i.e., the microfiber filter layer) is positioned as the first layer encountered by the gas (e.g., air) flow being filtered (i.e., the microfiber filter layer is the upstream layer).

[0040] In some embodiments, the filter media disclosed herein are pulse-cleanable. Pulse-cleanability is important for self-cleaning (e.g., via reverse air pulses) and is useful when the filter media is used for very high dust concentrations. Pulse cleanliness can be determined according to the modified ISO 11057 test method described in the Examples section.

[0041] In some embodiments, the composite filter media includes two or more fine fiber filter layers. In some embodiments, the composite filter media includes two or more depth-loaded layers (e.g., containing glass filter layers, melt-blown filter layers, or combinations thereof). In some embodiments, the composite filter media includes two or more support layers. These layers can be arranged in various orders, as long as one of the fine fiber filter layers is the most upstream layer.

[0042] Each filter layer and support layer can be a composite of multiple layers. For example, a deep load layer can be a composite of two or more different meltblown fiber layers that differ in either composition or fiber diameter.

[0043] In some embodiments, the filter medium disclosed herein has a thickness of at least 10 mils (0.25 mm). In some embodiments, the filter medium disclosed herein has a thickness of up to 60 mils (1.5 mm) or up to 30 mils (0.76 mm).

[0044] like Figure 1 As shown in the figure, a portion of the exemplary composite filter media 10 disclosed herein is illustrated, comprising at least two filter layers (i.e., layers performing filtration): a surface-loaded filter layer 20 and a depth-loaded filter layer (e.g., containing a glass filter layer) 22. In one embodiment, as... Figure 2 As shown in the figure, an exemplary composite filter medium 10 of this disclosure is illustrated, comprising: a surface-loaded layer 20, a depth-loaded filter layer (e.g., containing a glass filter layer) 22, and a support layer 18 positioned between the depth-loaded layer 22 and the surface-loaded layer 20. In another embodiment, as... Figure 3 As shown in the figure, an exemplary composite filter medium 10 of this disclosure is illustrated, comprising: a support layer 18, a surface load layer 20, and a depth load filter layer (e.g., containing a glass filter layer) 22 positioned between the support layer 18 and the surface load layer 20.

[0045] As shown in these exemplary embodiments, the surface-loaded filter layer 20 is positioned upstream of the depth-loaded filter layer 22 relative to the direction of gas flow (e.g., air flow) indicated by the arrow. That is, the surface-loaded filter layer 20 is the first layer encountered by the gas (e.g., air) flow during use.

[0046] The thickness of each of the filter layer and the support layer can be the same or different, and is not limiting. However, it should be noted that thickness affects filtration characteristics. It is desirable to minimize the total thickness of the media without significantly affecting other media characteristics, such as dust load capacity, efficiency, and permeability. This allows for more folds in the element, for example, preferably such that the filter element includes the maximum amount of media without adversely affecting the characteristics and performance of the filter element (e.g., efficiency, pressure drop, or dust load capacity).

[0047] Typically, in the filter media disclosed herein, the filter layer, and preferably the filter layer and the support layer, are adhered together using adhesives, bonding fibers, thermal bonding, ultrasonic bonding, self-adhesion, or combinations thereof. Preferred methods include the use of adhesives, bonding fibers, or combinations thereof. Particularly preferred methods are the use of adhesives (pressure-sensitive adhesives, hot-melt adhesives) applied using various techniques including, for example, powder coating, spraying, or the use of pre-formed adhesive webs. Typically, the adhesive is in a continuous layer, or it can be patterned (if desired), as long as the filter media does not delaminate during processing or use. Exemplary adhesives include hot-melt adhesives such as polyesters, polyamides, acrylates, or combinations thereof (blends or copolymers).

[0048] If an adhesive is used, the amount of adhesive can be readily determined by those skilled in the art. The desired level is one that provides suitable bonding between layers without adversely affecting gas flow through the medium. For example, the reduction in the Frazier permeability of the composite filter medium is preferably the reciprocal of the sum of the inverses of the permeabilities of each layer (i.e., (1 / A)). 渗透率 +1 / B 渗透率 +1 / C 渗透率 ) -1 The content of ) is less than 20%, or more preferably less than 10%. This also applies to any other lamination method.

[0049] To increase rigidity and provide better flow channels within the element, the filter media can be wrinkled. Therefore, in some embodiments, the filter media disclosed herein should have the characteristic of being able to withstand typical thermal wrinkling methods without media damage (which typically degrades media performance).

[0050] Filter media, whether or not wrinkled, can be folded into multiple pleats or folds and then installed in the filter housing or frame. Any number of pleating techniques can be used to pleat flat or wrinkled sheets, including but not limited to rotary pleating, blade pleating, etc. The wrinkled media can have any of a number of pleat support mechanisms applied to the pleated media as described in U.S. Patent No. 5,306,321. For example, wrinkled aluminum separators, hot-melt beads, and indentation (commonly referred to as PLEATLOC pleated media) can be used.

[0051] In some embodiments, the pleats are imprinted into the filter medium as spacers, thus effectively preventing these pleats from coalescing even when the medium is wet or overloaded. Indentations at the pleat tips, perpendicular to the pleat channel direction on both sides of the medium, keep the pleats separated and provide better flow channels for gas (e.g., air) to flow through the pleat packs in the element. This is especially beneficial in conical or cylindrical elements (such as...) Figures 9 to 14 In the element shown, the outer indentation can be deeper and wider than the inner indentation to keep the folds evenly spaced.

[0052] For media that do not wrinkle, other wrinkle-separating methods can be used for any of the media described herein, such as those involving adding hot melt adhesive beads between the wrinkles, or using a comb-like separator. The pleated material can be formed into cylinders or "tubes" and then bonded together, for example, by using an adhesive (e.g., a urethane-based hot melt adhesive) or ultrasonic welding (i.e., ultrasonic bonding).

[0053] In some embodiments, the filter layer, composite filter media (flat or wrinkled), and filter element disclosed herein are referred to as “high-efficiency.” In some embodiments, the high-efficiency filter layer disclosed herein is capable of removing at least 55%, at least 70%, at least 80%, at least 85%, at least 95%, at least 99.5%, at least 99.95%, or at least 99.995% (by quantity) of 0.4-micron-sized DEHS particles at a rate of 4 ft / min (2 cm / s). In some embodiments, the high-efficiency composite filter media (which may or may not be wrinkled) and / or filter element (typically wrinkled and pleated) disclosed herein exhibit an efficiency of at least F9 according to EN779:2012. In some embodiments, the high-efficiency filter element disclosed herein (typically wrinkled and pleated) exhibits an efficiency of at least E10, at least E11, or at least E12 according to EN1822:2009.

[0054] In some embodiments, the filter media exhibits an efficiency of at least 80% or greater than 80% at the most penetrating particle size, according to DEHS efficiency tests.

[0055] In some embodiments, the filter layer and / or composite filter media disclosed herein have good depth loading characteristics.

[0056] In some embodiments, the deep-loaded filter layer has a relatively low solidity. As used herein, solidity is the volume of solid fibers divided by the total volume of the filter media under discussion, typically expressed as a percentage, or in other words, the volume fraction of fibers in the media, expressed as the ratio of fiber volume / unit mass to media volume / unit mass. Suitable tests for determining solidity are described, for example, in U.S. Patent Publication No. 2014 / 0260137. Typically, at 1.5 psi (i.e., 0.1 kg / cm²), the solidity is... 2 A solids content of less than 20 percent (%), or typically less than 15 percent, under pressure is desirable.

[0057] In some embodiments, the filter layers and / or composite filter media disclosed herein exhibit high strength and high flexibility. This can be demonstrated by the relatively low loss of tensile strength after the layers and / or composite media have been folded or wrinkled. A tensile strength loss of less than 20% after the filter layer or filter media has been folded or wrinkled is desirable.

[0058] Surface-loaded filter layer

[0059] A surface-loaded filter layer is a filter layer that traps a significant portion of incident particles at its surface compared to its volume or thickness (i.e., in the "z" direction). In other words, a surface-loaded filter layer can prevent incident particles from passing through and can achieve a substantial surface load of trapped particles.

[0060] The surface-loaded filter layer of the filter media disclosed herein comprises fine fibers having an average fiber diameter of less than 1 micrometer (i.e., 1000 nanometers), or up to 0.5 micrometers, or up to 0.3 micrometers. This includes nanofibers and microfibers. Nanofibers are fibers with a diameter of less than 200 nanometers or 0.2 micrometers. Microfibers are fibers with a diameter greater than 0.2 micrometers but not greater than 10 micrometers. In some embodiments, the fine fibers have an average diameter of at least 0.01 micrometers, or at least 0.05 micrometers, or at least 0.1 micrometers.

[0061] In some embodiments, the surface-loaded filter layer has a density of less than 1 g / m².2 The basis weight is (or gsm). In some embodiments, the surface-loaded filter layer has a basis weight of at least 0.0001 g / m. 2 The base weight.

[0062] In some embodiments, the surface-loaded filter layer has an LEFS filtration efficiency of at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, or at least 80%. In some embodiments, the fine fiber filter layer has an LEFS filtration efficiency of up to 99%, up to 98%, up to 97%, up to 96%, up to 95%, up to 94%, up to 93%, up to 92%, up to 91%, or up to 90%.

[0063] Examples of fine fibers are disclosed in U.S. Patent No. 8,118,901.

[0064] The surface-loaded filter layer disclosed herein may include randomly distributed fine fibers that may interlock to form an interlocking network. Filtration performance is primarily achieved by the fine fiber barrier blocking the passage of particles. Structural properties such as stiffness, strength, and pleatability are typically provided by a support layer (e.g., a support layer with adhered fine fibers) contained within the filter medium.

[0065] In some embodiments, the surface-loaded filter layer may include a network of interlocking fine fibers. Such a network typically comprises fine fibers in the form of microfibers or nanofibers and relatively small spaces between the fibers. These spaces between the fibers typically range from 0.01 micrometers to 25 micrometers, or generally from 0.1 micrometers to 10 micrometers.

[0066] In some embodiments, the fine fibers increase the overall thickness of the filter media by less than 1 micrometer. In use, the filter can prevent incoming particles from passing through the surface-loaded filter layer and achieve a considerable surface loading of captured particles. Particles containing dust or other incoming particles rapidly form a dust cake on the surface of the fine fibers, maintaining high initial and overall particle removal efficiency. Even for relatively fine contaminants with particle sizes ranging from 0.01 micrometers to 1 micrometer, the filter media containing fine fibers exhibits very high dust capacity.

[0067] Suitable polymer materials for manufacturing fine fibers have significantly improved resistance to the adverse effects of heat, humidity, high flow rates, reverse pulse cleaning, operational abrasion, submicron particles, cleaning filters in use, and other harsh conditions.

[0068] Examples of fine fibers and polymeric materials used to make fine fibers are disclosed in U.S. Patent No. 8,118,901. Such polymeric materials include both addition polymeric materials and condensation polymeric materials, such as polyolefins, polyacetals, polyamides, polyesters, cellulose ethers and cellulose esters, polyalkylene sulfides, polyaryl oxides, polysulfones, modified polysulfone polymers, and mixtures thereof. Preferred materials belonging to these general categories include polyethylene, polypropylene, poly(vinyl chloride), polymethyl methacrylate (and other acrylic resins), polystyrene and its copolymers (including ABA-type block copolymers), poly(vinylidene fluoride), poly(vinylidene chloride), and polyvinyl alcohol in various degrees of hydrolysis (87% to 99.5%) in both crosslinked and non-crosslinked forms. Preferred addition polymers tend to be in a glassy state (Tg above room temperature). This is the case for polyvinyl chloride and polymethyl methacrylate, polystyrene polymer compositions or alloys thereof, or for polyvinylidene fluoride and polyvinyl alcohol materials.

[0069] One class of polyamide condensates is nylon material. The term "nylon" is a generic name for all long-chain synthetic polyamides. Typically, nylon nomenclature includes a series of numbers, such as in nylon-6,6, where the numbers indicate that the starting material is a C6 diamine and a C6 dicarboxylic acid (the first digit indicates the C6 diamine, and the second digit indicates the C6 dicarboxylic acid compound). Another type of nylon can be produced in the presence of a small amount of water via the condensation of ε-caprolactam. This reaction forms nylon-6 as a linear polyamide (made from a cyclic lactam, also known as ε-aminohexanoic acid). Furthermore, nylon copolymers are also conceivable.

[0070] Copolymers can be manufactured by combining various diamine compounds, various diacid compounds, and various cyclic lactam structures in a reaction mixture, and then forming a nylon with a polyamide structure using randomly positioned monomer materials. For example, nylon 6,6-6,10 materials are made from hexamethylenediamine, C6 diacid, and C... 10 Nylons are made from blends of diacids. Nylon 6-6, 6-6, 10 are produced by combining ε-aminohexanoic acid, hexamethylenediamine, and C6 diacid materials with C6 diacids. 10 Nylon is produced by the copolymerization of blends of dicarboxylic acid materials.

[0071] Block copolymers can also be used to manufacture fine fibers. When using such copolymers, the choice of swelling solvent is important. The solvent is chosen such that both blocks are soluble in it. An example is ABA (styrene-EP-styrene) or AB (styrene-EP) polymers in dichloromethane. If one component is not soluble in the solvent, it will form a gel. Examples of such block copolymers are KRATON copolymers of styrene-b-butadiene and styrene-b-hydrogenated butadiene (ethylene-propylene), PEBAX copolymers of e-caprolactam-b-ethylene oxide, SYMPATEX polyester-b-ethylene oxide, and polyurethanes of ethylene oxide and isocyanates.

[0072] Addition polymers such as polyvinylidene fluoride, syndiotactic polystyrene, copolymers of vinylidene fluoride and hexafluoropropylene, polyvinyl alcohol, polyvinyl acetate, amorphous addition polymers (such as poly(acrylonitrile) and its copolymers with acrylic acid and methacrylates), polystyrene, poly(vinyl chloride) and its various copolymers, poly(methyl methacrylate) and its various copolymers can be solution spun relatively easily because they are soluble at low pressure and low temperature. However, if highly crystalline polymers such as polyethylene and polypropylene are to be solution spun, they require solvents at high temperature and high pressure. Therefore, solution spinning of polyethylene and polypropylene is very difficult. Electrostatic solution spinning is a method used to manufacture fine fibers.

[0073] In some embodiments, the fine fibers comprise a single polymer material. In some embodiments, the fine fibers comprise a polymer mixture comprising a first polymer and a second, but different, polymer (different in polymer type, molecular weight, or physical properties), the polymer mixture being conditioned or treated at elevated temperatures. The polymer mixture may react and form a single chemical species, or may be physically combined into a blend composition by an annealing method. Annealing implies physical changes, such as changes in crystallinity, stress relaxation, or orientation. In some embodiments, the polymer material chemically reacts to form a single polymer species, such that differential scanning calorimetry reveals the single polymer material. Mixtures of similar polymers, such as compatible mixtures of nylon-like polymers, compatible mixtures of polyvinyl chloride-like polymers, and blends of polyvinylidene chloride polymers, can be used for fibers with surface-loaded filter layers.

[0074] In some embodiments, the microfibers comprise nylon, polyvinylidene fluoride, polyurethane, or combinations thereof (e.g., blends or copolymers).

[0075] Additive materials can also be used to form a surface coating on the fine fibers, which provides oleophobicity, hydrophobicity, or other associated improved stability when exposed to high temperatures, high humidity, and challenging operating conditions. Such fine fibers can have a smooth surface comprising a discrete layer of additive material, or an outer coating of additive material partially solubilized or alloyed in the polymer surface, or both.

[0076] Additives include fluorosurfactants, nonionic surfactants, and low molecular weight resins, such as tert-butylphenol resin with a molecular weight of less than about 3000. The resin is characterized by oligomerization bonds between phenol nuclei in the absence of methylene bridging groups. The positions of the hydroxyl and tert-butyl groups can be randomly positioned around the ring. Bonding between phenol nuclei always occurs next to the hydroxyl group, rather than randomly. Similarly, the polymer material can be combined with an alcohol-soluble non-linear polymeric resin formed from bisphenol A. This material is similar to the aforementioned tert-butylphenol resin because it is formed using oligomerization bonds that directly connect the aromatic ring to the aromatic ring in the absence of any bridging groups such as alkylene or methylene groups.

[0077] In some embodiments, the polymer and optional additives are selected to provide temperature resistance, moisture resistance or dampness resistance, and solvent resistance. In some embodiments, the polymer material and optional additives are selected so that, depending on the end use, the filter remains intact for a period of time of 1 hour or 3 hours at a variety of operating temperatures (i.e., 140°F, 160°F, 270°F, 300°F) while retaining 30%, 50%, 80%, or 90% of the effective fine fibers in the filter layer. It is important that the filter does not deteriorate at low humidity, high humidity, or in water-saturated gases (e.g., air) at these temperatures.

[0078] In some embodiments, polymers and optional additives are selected to provide adhesion of the material to the remainder of the media structure, such that the composite media can be processed into filter structures including pleats, rolled materials, and other structures without significant delamination.

[0079] The fine fiber filter layer may comprise a bilayer or multilayer structure, wherein the filter contains one or more surface-loaded filter layers, which are combined with or separated from one or more synthetic webs, cellulose webs, or blended webs. Another preferred motif is a structure comprising a blend of fine fibers or other fibers in a matrix.

[0080] For pulse-cleaning applications, an extremely thin layer of fine fibers can help minimize pressure loss and provide an outer surface for particle capture and release. For self-cleaning applications, a thin fiber layer with a diameter of less than 1 micrometer or less than 0.5 micrometers is preferred. Good adhesion between the fine fibers and adjacent layers (e.g., deep-loaded layers) is important. The filter media is restored by repeated reverse pulses to self-clean the surface. When large forces are applied to the surface, fine fibers with poor adhesion to the substrate may delaminate under reverse pulses, penetrating the substrate from the inside of the filter to reach the surface-loaded filter layer.

[0081] Deep load layer

[0082] A deep loading layer is a filter layer that traps particles throughout its entire volume. Therefore, compared to loading a filter layer on its surface, dirt is trapped over the entire thickness of the filter layer (i.e., in the "z" direction).

[0083] Deeply loaded layers are typically characterized by their porosity, density, and percentage of solids content. For example, a 5% solids content medium means that approximately 5% of the total volume is composed of solids (e.g., fibrous materials), and the remainder is void space filled with air or other fluids.

[0084] In some embodiments, the deep-loaded filter layer has a relatively low solids content. Typically, the deep-loaded filter layer has a solids content of 1.5 psi (i.e., 0.1 kg / cm³). 2 Under pressure of less than 20%, typically less than 15%, solids content. In some embodiments, the deep-loaded filter layer disclosed herein has a solids content of less than 20%, typically less than 15%, under pressure of 1.5 psi (i.e., 0.1 kg / cm²). 2 At least 5% solids content under pressure.

[0085] In some embodiments, when evaluated separately from the rest of the construction, the depth-loaded filter layer has a density of at least 8 liters / m² / second (l / m²). 2 / s), at least 20l / m 2 / s, at least 40l / m 2 / s, at least 80l / m 2 / s, at least 100l / m 2 / s, or at least 200 l / m 2 Fraser permeability of / s (pressure differential set at 0.5 inches of water column). In some embodiments, the depth-loaded filter layer has up to 1000 l / m when evaluated separately from the rest of the construction. 2 / s, up to 800 l / m 2 / s, up to 600l / m 2 / s, up to 400l / m 2 / s, or up to 200 l / m2 Fraser permeability / s (pressure differential set at 0.5 inches of water column).

[0086] Another commonly used characteristic of depth-loaded filter media is fiber diameter. Generally, for a given percentage of solids, smaller diameter fibers will make the filter media more effective at capturing smaller particles. Since smaller fibers occupy less volume compared to larger fibers, they can be packaged together in larger quantities without increasing the total solids percentage.

[0087] Because depth-loaded filter layers essentially capture particles across their entire volume or depth, they can load a greater weight and volume of particles compared to surface-loaded filter layers over the filter media's lifetime. However, depth-loaded filter layers tend to have lower efficiency than surface-loaded filter layers. To facilitate this high loading capacity, depth-loaded filter layers with low solids content are typically chosen. This can result in a large average pore size, which may allow some particles to pass through the filter more easily. Gradient density systems and / or the addition of surface-loaded filter layers can provide improved efficiency characteristics.

[0088] In some embodiments, the deep loading layer of the filter media disclosed herein is a high-efficiency filter layer. In some embodiments, the high-efficiency filter layer exhibits a filtration efficiency of at least 55% or at least 70% for DEHS (diethylhexyl sebacate) particles with a size of 0.4 micrometers at a speed of 4 ft / min (2 cm / s). Preferably, it exhibits a filtration efficiency of at least 80%, at least 85%, at least 95%, at least 99.5%, at least 99.95%, or at least 99.995% for most penetrating size (MPPS) particles at a speed of 4 ft / min (2 cm / s).

[0089] In some embodiments, the deep loading layer exhibits filtration efficiencies of up to 99%, up to 99.5%, up to 99.97%, or up to 99.997% at 4 ft / min (2 cm / s) and 0.4 micron-sized DEHS (diethylhexyl sebacate) particles.

[0090] In some embodiments, the depth-loaded filter layer disclosed herein exhibits at least 1 g / m² under a final pressure drop exceeding the initial value of 2 inches of water column (i.e., 500 Pa). 2 (or gsm), at least 2g / m 2 At least 3g / m 2 At least 4g / m 2 At least 5g / m 2 At least 6g / m 2 At least 7g / m 2 At least 8g / m 2 At least 9g / m2 or at least 10g / m 2 Salt loading capacity. Typically, a higher salt loading capacity is better, as it is an indicator of product lifespan. In some embodiments, deep-loaded filter layers have exhibited up to 10 g / m³ under pressure rises exceeding the initial value of 500 Pascals. 2 Salt loading capacity.

[0091] In some embodiments, the thickness of the deep load layer is at least 0.005 inches (125 micrometers), and typically at least 0.01 inches (250 micrometers). In some embodiments, the thickness of the deep load layer is up to 0.02 inches (500 micrometers).

[0092] In some embodiments, the deep load filter layer has a density of at least 10 g / m³. 2 At least 20g / m 2 At least 30g / m 2 At least 40g / m 2 or at least 50g / m 2 The basis weight. In some embodiments, the depth-loaded filter layer reaches up to 150 g / m. 2 Up to 140g / m 2 Up to 130g / m 2 Up to 120g / m 2 Up to 110g / m 2 Up to 100g / m 2 The base weight.

[0093] In some embodiments, the deep loading layer exhibited at least 0.5 g / ft under a 2-inch water pressure rise and using 0.3-micron NaCl particles at 10 ft / min (5.8 cm / s). 2 (5.4g / m 2 The dust loading capacity was [not specified]. In some embodiments, deep loading layers showed up to 5 g / ft at a 2-inch water pressure rise and using 0.3-micron NaCl particles at 10 ft / min (5.8 cm / s). 2 (53.8g / m 2 Dust load capacity.

[0094] In some embodiments, the deep loading layer includes a glass filter layer, a meltblown filter layer, or a combination thereof.

[0095] In some embodiments, the depth-loaded layer includes a glass-containing filter layer. In some embodiments of the glass-containing filter layer, this layer includes glass fibers having an average diameter of up to 2 micrometers, up to 1 micrometer, or up to 0.5 micrometers. In some embodiments, the glass fibers have an average diameter of at least 0.01 micrometers, at least 0.05 micrometers, at least 0.1 micrometers, at least 0.2 micrometers, at least 0.3 micrometers, or at least 0.4 micrometers.

[0096] The glass-containing filter layer may also include fibers other than glass fibers. For example, it may contain multi-component fibers, typically bicomponent fibers, which act as binders. A preferred example is a bicomponent binder fiber, which is a core-skin fiber having a low-melting-point polyester sheath and a high-melting-point polyester core. Bicomponent fibers typically have a fiber diameter of at least 10 micrometers.

[0097] The glass-containing filter layer may also comprise polyester fibers that are different from the multicomponent fibers. Preferred glass-containing filter layers disclosed herein comprise only glass fibers and bicomponent bonded fibers. In some embodiments, the polyester fibers, different from the multicomponent bonded fibers, have an average diameter of 10 to 14 micrometers.

[0098] The fibers containing the glass filter layer can be manufactured by a variety of methods. In some embodiments, the glass filter layer is formed using a wet web-forming method.

[0099] Although the bonding fibers in the glass-containing filter layer are intended to avoid the use of any bonding resin, such resin can be added to further enhance its strength. Examples of suitable bonding resins include solvent-based or water-based latex resins, water-based styrene-acrylic resins, solvent-based phenolic resins, and solvent-based non-phenolic resins, such as those from Lubrizol, Cleveland, OH, USA, under the trade name HYCAR 26138. Typically, if used, the bonding resin may be present in the glass-containing filter layer in an amount up to 10 wt%, up to 5 wt%, or up to 1 wt% of the total weight of the glass-containing filter layer. Preferably, no bonding resin is used in the glass-containing filter layer (or any layer of the filter media).

[0100] Suitable examples of glass filter layers include those described in U.S. Patent Nos. 7,309,372, 7,314,497, 7,985,344, 8,057,567 and 8,268,033, and U.S. Publications 2006 / 0242933 and 2008 / 0245037.

[0101] In some embodiments, the deep-loaded layer includes a meltblown filter layer. Typically, meltblowing is a nonwoven web forming method in which molten polymer resin is extruded and stretched using heated, high-speed gas (e.g., air) to form filaments. The filaments are cooled and then collected as a web on a moving screen. This method is similar to spunbond methods, but meltblown fibers are typically much finer.

[0102] Typically, meltblown fibers have an average diameter of no more than 20 micrometers. In some embodiments, the meltblown filter layer comprises meltblown fibers having an average diameter of up to 10 micrometers, up to 5 micrometers, up to 4 micrometers, or up to 3 micrometers. In some embodiments, the meltblown filter layer comprises meltblown fibers having an average diameter of at least 0.5 micrometers, at least 1 micrometer, at least 1.5 micrometers, or at least 2 micrometers. In some embodiments, the meltblown fibers have an average diameter of 2 to 3 micrometers.

[0103] In some embodiments, the meltblown filter layer may include support fibers as described in International Publication No. WO2013 / 025445, if desired, to improve performance. However, media with high levels of compressibility use little or no support fibers as described in International Publication No. WO2013 / 025445 in the meltblown filter layer. These support fibers provide support for the media fibers and add improved handling, greater tensile strength, and result in lower compressibility of the media.

[0104] In some embodiments, the meltblown filter layer includes a continuous gradient structure having: larger fibers and larger openings at a first main surface, and smaller fibers and smaller openings at a second main surface. In some embodiments of this configuration, the second main surface of the meltblown filter layer is adjacent to a support layer, and the first main surface is positioned as the upstream surface (i.e., the first layer encountered by the gas (e.g., air) flow during use).

[0105] In some embodiments, the meltblown filter layer comprises a composite of multiple meltblown fibers having: larger fibers and a structure with larger openings at a first main surface of the meltblown composite, and smaller fibers and a structure with smaller openings at a second main surface of the meltblown composite. In some embodiments of this configuration, the second main surface of the meltblown filter layer is adjacent to a support layer, and the first main surface is positioned adjacent to a surface-loaded filter layer.

[0106] In some embodiments, meltblown fibers can be prepared from a variety of polymers suitable for meltblowing. Examples include polyolefins (particularly polypropylene), ethylene-chloro-trifluoroethylene, other hydrophobic polymers, or non-hydrophobic polymers with hydrophobic coatings or additives (e.g., polybutylene terephthalate, polystyrene, polylactic acid, polycarbonate, nylon, polyphenylene sulfide), or combinations thereof (e.g., blends or copolymers). Preferred polymers are polyolefins, such as polypropylene, polyethylene, and polybutene.

[0107] In some embodiments, the meltblown filter layer comprises fibers made of polypropylene, polybutylene terephthalate, or combinations thereof. Particularly preferred meltblown fibers are made of polypropylene to enhance the waterproof properties of the preferred filter media disclosed herein.

[0108] In some embodiments, the meltblown filter layer is hydrophobic. This means that the layer exhibits a water contact angle greater than 90 degrees. The fibrous material used to manufacture the layer may be hydrophobic (e.g., polyolefin) or include hydrophobic additives, or be coated with a hydrophobic material. Similarly, in some embodiments, the glass-containing filter layer is coated with a hydrophobic coating to enhance water resistance. Alternatively, the deep-loaded filter layer may be treated with plasma processing techniques.

[0109] Suitable hydrophobic materials have little or no affinity for water, or completely repel water, thereby preventing or limiting the passage of water through the filter medium. Typically, the hydrophobic material exhibits a contact angle greater than 90 degrees when tested with water. Examples of hydrophobic materials include fluorinated compounds, particularly fluoropolymers as described in U.S. Patent No. 6,196,708.

[0110] Examples of useful fluoropolymers include those having a fluoroalkyl moiety, or preferably a perfluoroalkyl moiety. These fluoropolymers include, for example, fluoroalkyl esters, fluoroalkyl ethers, fluoroalkyl amides, and fluoroalkyl urethanes. The fluoroalkyl moiety and / or perfluoroalkyl moiety typically extend from the polymer backbone.

[0111] Fluoropolymers may include a variety of monomer units. Exemplary monomer units include, for example, fluoroalkyl acrylates, fluoroalkyl methacrylates, fluoroalkyl arylcarbamates, fluoroalkyl allylcarbamates, fluoroalkyl maleates, fluoroalkyl acrylates, fluoroalkyl amides, sulfonamide fluoroalkyl acrylates, etc. Fluoropolymers may optionally have additional non-fluorinated monomer units, which include, for example, unsaturated hydrocarbons (e.g., olefins), acrylates, and methacrylates. Other examples of suitable fluoropolymers are provided in U.S. Patent No. 3,341,497.

[0112] Commercially available fluoropolymers include those available from Huntsman, Charlotte, NC, under the trade name OLEOPHOBOL CPX, as well as 3M Protective Material PM-490 (a nonionic fluoropolymer resin), 3M Protective Material PM-3633 (a fluoropolymer emulsion), and 3M L-21484 (a fluorinated amino salt derivative that can be diluted in water or polar organic solvents), all of which are available from 3M Co., St. Paul, MN, USA.

[0113] Other exemplary commercially available fluoropolymers are provided in the form of aqueous emulsions. The fluoropolymer can be extracted from the aqueous emulsion by removing the aqueous carrier. The fluoropolymer can then be solvated in an organic solvent. To facilitate solvation of the fluoropolymer, a compound such as acetone can optionally be added to the aqueous emulsion to disrupt it. Furthermore, the fluoropolymer particles can optionally be milled after water removal to make solvation easier and faster.

[0114] The methods used to coat this material are conventional and well known to those skilled in the art. Typical coating weights are at least 0.5 wt% and generally no more than 3 wt%.

[0115] support layer

[0116] The filter media disclosed herein includes a support layer. The support layer can be any of a variety of porous materials, including fibrous materials, metal mesh, etc. Typically, the fibrous material used for the support layer is made of natural and / or synthetic fibers. It can be woven or nonwoven. It can be spunbond, wet-laid, etc.

[0117] In some embodiments, the support layer comprises fibers having an average diameter of at least 5 micrometers or at least 10 micrometers. In some embodiments, the support layer may comprise fibers with an average diameter of up to 250 micrometers.

[0118] In some embodiments, the support layer has a strength of at least 50 g / m². 2 The base weight is either g / m² or at least 100 g / m². In some embodiments, the support layer has a maximum weight of 260 g / m². 2 (or gsm), up to 200g / m 2 or at most 150g / m 2 The base weight.

[0119] In some embodiments, the thickness of the support layer is at least 0.005 inches (125 micrometers), typically at least 0.01 inches (250 micrometers). In some embodiments, the thickness of the support layer is up to 0.03 inches (750 micrometers).

[0120] In some embodiments, when evaluated separately from the rest of the construction, the support layer has a strength of at least 10 cubic feet per minute (ft) at 125 Pa. 3 / min)(80.2l / m at 200Pa 2 The air permeability is measured in cubic feet per minute (ft / s). In some embodiments, when evaluated separately from the rest of the structure, the air permeability at 125 Pa is up to 1000 cubic feet per minute (ft / s). 3 / min)(8020l / m at 200Pa) 2 / s).

[0121] In some embodiments, the support layer has a Gurley stiffness of at least 1000 mg, and typically at least 5000 mg. In some embodiments, the support layer may have a Gurley stiffness of up to 10,000 mg. A method for measuring Gurley stiffness is described in TAPPI No. T543.

[0122] Examples of suitable materials for the support layer (i.e., the substrate) include spunbond, wet-laid, carded, or meltblown nonwoven materials. Suitable fibers can be cellulose fibers, glass fibers, metal fibers, or synthetic polymer fibers, or combinations thereof. Fibers can be in woven or nonwoven form. Extruded and perforated plastic or metal mesh materials are other examples of filter substrates. Examples of synthetic nonwovens include polyester nonwovens, nylon nonwovens, polyolefin (e.g., polypropylene) nonwovens, polycarbonate nonwovens, or blends or multicomponent nonwovens thereof. Sheet-like substrates (e.g., cellulose webs, synthetic webs, and / or glass webs or composite webs) are typical examples of filter substrates. Other preferred examples of suitable substrates include polyester fibers or bicomponent polyester fibers (as described herein with respect to glass filter layers) in spunbond fabrics, or poly(propylene terephthalate) / poly(ethylene terephthalate) or poly(ethylene terephthalate) / poly(ethylene terephthalate) bicomponent fibers.

[0123] In some embodiments, the support layer comprises wet-laid fibers. In some embodiments, the support layer comprises wet-laid cellulose fibers, polyester fibers, or combinations thereof.

[0124] In some embodiments, the support layer is hydrophobic. The fibrous material used to fabricate the support layer may be hydrophobic (e.g., polyolefin) or include hydrophobic additives, or it may be coated with a hydrophobic material (such as those materials described herein for hydrophobic coatings on glass filter layers), or it may be treated with plasma processing techniques. Alternatively, if wet-laid, a hydrophobic resin may be applied during the wet-laid process.

[0125] Optional loose fabric layer

[0126] In some embodiments, a sparse cloth layer may be used to enhance the stiffness of the filter media disclosed herein. Typically, the sparse cloth layer is disposed between a surface-loaded filter layer and a depth-loaded filter layer. Materials that can be used for the sparse cloth layer typically have high permeability (i.e., “perm”) (e.g., greater than 1600 l / m). 2 ( / s) and is thin (e.g., less than 0.005 inches), thus having minimal impact on the performance of flat sheets or filter elements. Examples of such loosely woven materials include those available from Midwest Filtration, Cincinnati, OH, under the trade names FINONC303NW and FINON C3019 NW. Others are described, for example, in U.S. Patent Publication 2009 / 0120868.

[0127] Filter elements and applications

[0128] The filter media disclosed herein can then be manufactured into filter elements (i.e., filter components), including, for example, flat-plate filters, cartridge filters, or other filter elements (e.g., cylindrical or conical). Examples of such filter elements are described in U.S. Patent Nos. 6,746,517, 6,673,136, 6,800,117, 6,875,256, 6,716,274, and 7,316,723, and U.S. Patent Application No. 2014 / 0260142.

[0129] The filter media can be wrinkled. Exemplary wrinkles have a depth of 0.020 inches to 0.035 inches (0.5 mm to 0.9 mm). The wrinkled filter media can then typically be pleated to form a pleated package, as is known in the art, and then placed and sealed into a housing.

[0130] The filter elements disclosed herein can be used in industrial filtration (e.g., in dust collectors, as well as commercial and residential HVAC systems).

[0131] Figures 4 to 14 Various embodiments of the filter elements disclosed herein are depicted for use in gas turbine air intake systems or industrial air cleaners.

[0132] exist Figure 4 The diagram shows a pleated panel element 200 in perspective. Panel element 200 includes a media package 202 of pleated media 204. Pleated media 204 may include the filter media described herein. In the illustrated embodiment, media package 202 is held within a frame 206, an example of which is a rectangular frame 206. Frame 206 typically includes gaskets (not shown) for allowing element 200 to seal onto a tube sheet in the intake system. Figure 4 In the diagram, the upstream side of the pleated medium 204 with a surface-loaded filter layer is shown at 205, on the same side as the incoming gas (e.g., air) indicated by arrow 207. Clean gas (e.g., air) is indicated by arrow 208 and is generated from the downstream side of the medium 204.

[0133] Figure 5 A perspective view of a bag filter element 210 is depicted. The bag element 210 includes a filter media layer 212, which may contain the filter media disclosed herein. In the illustrated embodiment, the bag element 210 includes a plurality of panel pairs 213, 214, each panel pair 213, 214 forming a V-shape. The filter media 212 is secured to a frame 216. The frame 216 typically carries gaskets for allowing the bag element 210 to be sealed to a tube sheet. In this arrangement, the media 212 has an upstream meltblown side 217 located inside the V-shape and a downstream side 218 located outside the V-shape.

[0134] Figures 6 to 8 A view depicting a micro-pleated or multi-V element 220 is shown. Element 220 includes a frame 222 for holding the filter media package 224. Figure 8 The medium package 224 contains a plurality of micro-pleats. The micro-pleats are arranged in panel 226, and element 220 includes a plurality of micro-pleated panel pairs 227, 228 of the medium of the present invention. Figure 6 Each micro-pleated panel forms a V-shape. Figure 6 In the diagram, panels 227 and 228 are shown with hidden lines because the top portion of frame 222 obscures the view of panels 227 and 228. Frame 222 defines multiple dirty gas (e.g., air) inlets 229. Figure 7 The inlet leads to the inner portion of each V-shape of each pleated panel pair 227, 228. Each pleated panel pair 227, 228 includes an upstream side 230 located inside the V-shape and a downstream side 231 located outside the V-shape.

[0135] Figures 9 to 14 Various embodiments of tubular pleated filter elements are shown. Figure 9A cylindrical pleated element 240 with a media package 242 is shown, the media package including the filter media disclosed herein, the cylindrical pleated element having an upstream side 244 and a downstream side 246. The downstream side 246 is located inside the internal volume of the element 240.

[0136] Figure 10 Two of a plurality of cylindrical elements 240 are depicted, which are axially aligned such that they are stacked end to end.

[0137] exist Figure 11 In this design, the cylindrical element 240 and the partially tapered element 250 are axially aligned. The partially tapered element 250 is a tubular element having a media package 252, which may include the filter media disclosed herein. The element has an upstream side 254 and a downstream side 256. The tapered element 250 has a first end 258, the diameter of which matches the diameter of the cylindrical element 240. The tapered element 250 includes a second end 260, the diameter of which is larger than the diameter of the first end 258, thereby forming a partial taper shape.

[0138] Figure 12 Two partially tapered elements 270 and 280 are depicted, which are axially arranged and joined end-to-end. Each of the elements 270 includes a media package 272 or 282 forming a tube, which may include the filter media disclosed herein. Media packages 272 and 282 each have an upstream side 274 or 284 and a downstream side 276 or 286.

[0139] Figure 13 A single tapered element 270 is shown. Element 270 can be installed independently in the air intake system of a gas turbine, rather than as... Figure 11 and Figure 12 The components shown are mounted in pairs.

[0140] Figure 14 This is another embodiment of a filter element 290 having a media package 292, which may include the filter media disclosed herein. The media package 292 is pleated and formed into a tubular shape. In this embodiment, the tubular shape is elliptical, and in one example embodiment, the ratio of the minor axis to the major axis of the ellipse is about 0.7 to 0.9. The media 292 includes an upstream side 294 and a downstream side 296.

[0141] Figure 15This is another embodiment of a filter element in the form of an oval structure, which may include the filter medium disclosed herein. The filter element includes a filter medium 310 having end caps 320 on each of a first end 312 and a second end 314 of the filter medium 310. The end cap 320 on the first end 312 of the filter medium 310 may have an opening allowing access to the internal volume of the filter cartridge. The end caps 320 on the opposite ends of the filter medium 310 may be closed such that the end caps prevent access to the internal volume of the filter cartridge and that gas (e.g., air) entering the internal volume of the filter cartridge through the end caps 320 on the first end 312 of the filter medium 310 must exit through the filter medium in the filter element.

[0142] See Figure 15 In one or more alternative embodiments, both end caps 320 may be open to allow access to the internal volume of the filter element. In one or more embodiments, gaskets 322 may be provided on the end caps 320 to seal the filter cartridge at openings in, for example, tube sheets, venturi tubes, or other structures that deliver gas to the internal volume of the filter element. A tube axis 311 extends through the tubular filter cartridge between a first end 312 and a second end 314. The filter medium 310 in the filter cartridge described herein defines an outer surface 316 and an inner surface 318 positioned around the tube axis 311. The inner surface 318 faces the internal volume of the filter cartridge 310, while the outer surface 316 faces away from the internal volume.

[0143] exist Figure 15 In the filter element, end cap 320 may include an alignment mechanism in the form of, for example, optional tabs 324, with recesses 326 located within the tabs. The recesses 326 may be sized to receive upper members 352 and lower members 354 of a fork 350, on which the filter cartridge may be mounted in the filtration system. In one or more embodiments, each of the recesses 326 may be described as having an opening facing the internal volume of the filter cartridge, wherein the recess 326 extends toward the inner circumference 328 of the end cap 320. While in the depicted embodiments each recess 326 is formed in a single tab 324, in one or more alternative embodiments, the recess 326 may be formed between two members protruding from the inner circumference 328 of the end cap 320, wherein the two members forming the recess 326 are not identical structural members. Using two tabs 324 in combination with the fork 350 having two members 352 and 354 can advantageously prevent, or at least limit, rotation of the filter cartridge about its tubular axis 311 when mounted on the fork 350 in the filtration system. This filter element is described in further detail in U.S. Patent Publication No. 2014 / 0260142.

[0144] It should be understood that the above representations and in Figures 4 to 15 Each of the filter elements depicted may be a flat or corrugated medium and / or operatively mounted in an air intake system for a gas turbine or other ventilation system.

[0145] In operation, the gas to be filtered (e.g., air) is guided through an upstream-side, surface-loaded fine fiber filter layer, and then through a downstream-side filter medium in a corresponding filter element typically mounted in a tube sheet. The filter medium removes at least some particles from the gas (e.g., air) flow. After passing through the downstream side of the medium, the filtered gas (e.g., air) is then directed to the gas turbine.

[0146] Exemplary embodiments

[0147] Example 1 is a gas filter medium comprising: a surface-loaded filter layer comprising fine fibers having an average diameter of less than 1 micrometer; a depth-loaded filter layer; and a support layer; wherein the layers are configured and arranged for placement in a gas flow, wherein the surface-loaded filter layer is the upstream layer.

[0148] Example 2 is the filter medium of Example 1, and the filter medium is pulse-cleanable.

[0149] Example 3 is a filter medium of Example 1 or 2, wherein the depth-loaded filter layer is positioned between the surface-loaded layer and the support layer.

[0150] Example 4 is a filter medium of any one of Examples 1 to 3, wherein the fine fibers have an average diameter of up to 0.5 micrometers.

[0151] Example 5 is the filter medium of Example 4, wherein the fine fibers have an average diameter of up to 0.3 micrometers.

[0152] Example 6 is a filter medium of any one of Examples 1 to 5, wherein the fine fibers have an average diameter of at least 0.01 micrometers.

[0153] Example 7 is the filter medium of Example 6, wherein the fine fibers have an average diameter of at least 0.1 micrometers.

[0154] Example 8 is a filter medium of any one of Examples 1 to 7, wherein the fine fibers comprise nylon, polyvinylidene fluoride, polyurethane, or a combination thereof.

[0155] Example 9 is a filter medium of any one of Examples 1 to 8, wherein the surface-loaded filter layer has a LEFS filtration efficiency of at least 30%.

[0156] Example 10 is the filter medium of Example 9, wherein the surface-loaded filter layer has a LEFS filtration efficiency of at least 70%.

[0157] Example 11 is the filter medium of Example 10, wherein the surface-loaded filter layer has a LEFS filtration efficiency of at least 80%.

[0158] Example 12 is a filter medium of any one of Examples 1 to 11, wherein the surface-loaded filter layer has a maximum LEFS filtration efficiency of up to 99%.

[0159] Example 13 is the filter medium of Example 12, wherein the surface-loaded filter layer has a maximum LEFS filtration efficiency of up to 95%.

[0160] Example 14 is the filter medium of Example 13, wherein the surface-loaded filter layer has a maximum LEFS filtration efficiency of up to 90%.

[0161] Example 15 is a filter medium of any one of Examples 1 to 14, wherein the deep-loaded filter layer comprises a high-efficiency glass-containing filter layer, a high-efficiency melt-blown filter layer, or a combination thereof.

[0162] Example 16 is the filter medium of Example 15, wherein the deep-loaded filter layer comprises a high-efficiency glass-containing filter layer, and the high-efficiency glass-containing filter layer comprises glass fibers and multi-component bonding fibers.

[0163] Example 17 is the filter medium of Example 16, wherein the high-efficiency glass-containing layer comprises a binding resin of up to 10 wt% based on the total weight of the glass-containing layer.

[0164] Example 18 is a filter medium of Example 16 or 17, wherein the high-efficiency multi-component bonded fiber containing a glass filter layer comprises a bicomponent fiber having a low-melting-point polyester sheath and a higher-melting-point polyester core.

[0165] Example 19 is a filter medium of any one of Examples 16 to 18, wherein the high-efficiency glass-containing filter layer further comprises polyester fibers different from the multi-component bonding fibers.

[0166] Example 20 is the filter medium of Example 19, wherein the polyester fibers, different from the multi-component bonded fibers, have an average diameter of 10 micrometers to 14 micrometers.

[0167] Example 21 is a filter medium of any one of Examples 16 to 20, wherein the high-efficiency glass-containing filter layer comprises glass fibers having an average diameter of 0.4 micrometers to 0.5 micrometers.

[0168] Example 22 is the filter medium of Example 15, wherein the deep load filter layer comprises a high-efficiency meltblown filter layer.

[0169] Example 23 is the filter medium of Example 22, wherein the high-efficiency meltblown filter layer comprises meltblown fibers, which comprise polypropylene, polybutylene terephthalate, or a combination thereof.

[0170] Example 24 is a filter medium of Example 22 or 23, wherein the high-efficiency meltblown filter layer comprises meltblown fibers having an average diameter of 0.5 micrometers to 10 micrometers.

[0171] Example 25 is the filter medium of Example 24, wherein the high-efficiency meltblown filter layer comprises meltblown fibers having an average diameter of 0.5 micrometers to 4 micrometers.

[0172] Example 26 is the filter medium of Example 25, wherein the high-efficiency meltblown filter layer comprises meltblown fibers having an average diameter of 1 micrometer to 3 micrometers.

[0173] Example 27 is the filter medium of Example 25, wherein the high-efficiency meltblown filter layer comprises meltblown fibers having an average diameter of 2 to 3 micrometers.

[0174] Example 28 is a filter medium of any one of Examples 1 to 27, wherein the deep-loaded filter layer exhibits a DEHS filtration efficiency of at least 55%.

[0175] Example 29 is the filter medium of Example 28, wherein the deep-loaded filter layer exhibits a DEHS filtration efficiency of at least 70%.

[0176] Example 30 is a filter medium of any one of Examples 1 to 29, wherein the deep-loaded filter layer exhibits a DEHS filtration efficiency of up to 99.997%.

[0177] Example 31 is the filter medium of Example 30, wherein the deep-loaded filter layer exhibits a DEHS filtration efficiency of up to 99.97%.

[0178] Example 32 is the filter medium of Example 31, wherein the deep-loaded filter layer exhibits a DEHS filtration efficiency of up to 99.5%.

[0179] Example 33 is a filter medium of any one of Examples 1 to 32, wherein the depth-loaded filter layer has a maximum strength of 150 g / m³. 2 The base weight.

[0180] Example 34 is a filter medium of any one of Examples 1 to 33, wherein the depth-loaded filter layer has a density of at least 10 g / m³.2 The base weight.

[0181] Example 35 is a filter medium of any one of Examples 1 to 34, wherein the deep-loaded filter layer exhibits at least 1 g / m³ under a pressure rise exceeding the initial value of 500 Pascals. 2 Salt loading capacity.

[0182] Example 36 is a filter medium of any one of Examples 1 to 35, wherein the deep-loaded filter layer exhibits a maximum pressure rise of up to 10 g / m³ above the initial value of 500 Pascals. 2 Salt loading capacity.

[0183] Example 37 is a filter medium of any one of Examples 1 to 36, wherein the support layer has a Gurley stiffness of 1000 mg or higher.

[0184] Example 38 is the filter medium of Example 27, wherein the support layer has a strength of at least 10 ft at 125 Pa. 3 / min (80.2 l / m at 200 Pa) 2 Air permeability ( / s).

[0185] Example 39 is a filter medium of any one of Examples 1 to 38, wherein the support layer comprises wet-laid fibers.

[0186] Example 40 is the filter medium of Example 39, wherein the wet-laid web fibers comprise cellulose, polyester, or a combination thereof.

[0187] Example 41 is a filter medium of any one of Examples 1 to 40, wherein the support layer has a maximum strength of 260 g / m³. 2 The base weight.

[0188] Example 42 is a filter medium of any one of Examples 1 to 41, wherein the support layer has a concentration of at least 50 g / m³. 2 The base weight.

[0189] Example 43 is a filter medium of any one of Examples 1 to 42, further comprising a loosely packed cloth layer disposed between the surface-loaded filter layer and the depth-loaded filter layer.

[0190] Example 44 is a filter medium of any one of Examples 1 to 43, having a thickness of at least 10 mils (0.25 mm).

[0191] Example 45 is a filter medium of any one of Examples 1 to 44, having a thickness of up to 60 mils (1.5 mm).

[0192] Example 46 is the filter medium of Example 45, having a thickness of up to 30 mils (0.76 mm).

[0193] Example 47 is a filter medium of any one of Examples 1 to 46, wherein the layers are adhered together by an adhesive, bonding fibers, thermal bonding, ultrasonic bonding, self-adhesion, or a combination thereof.

[0194] Example 48 is a filter medium of any one of Examples 1 to 47, which shows an efficiency of at least F9 according to EN779:2012.

[0195] Example 49 is the filter medium of Example 48, which shows an efficiency of at least 80% or greater than 80% at the most penetrating particle size according to DEHS efficiency tests.

[0196] Example 50 is a filter medium of any one of Examples 1 to 49, wherein the filter medium is an air filter medium.

[0197] Example 51 is a gas filter element, which includes a housing and a gas filter medium of any one of Examples 1 to 50.

[0198] Example 52 is a gas filter element of Example 51, which exhibits an efficiency of at least F9 according to EN779:2012.

[0199] Example 53 is a gas filter element of Example 52, which exhibits an efficiency of at least E10 according to EN1822:2009.

[0200] Example 54 is a gas filter element of Example 53, which exhibits an efficiency of at least E11 according to EN1822:2009.

[0201] Example 55 is a gas filter element of Example 54, which exhibits an efficiency of at least E12 according to EN1822:2009.

[0202] Example 56 is a gas filter element of any one of Examples 51 to 55, wherein the gas filter element is flat, cylindrical or conical.

[0203] Example 57 is a gas filter element of any one of Examples 51 to 56, wherein the gas filter element is pleated.

[0204] Example 58 is a method for filtering a gas (e.g., air), the method comprising guiding the gas through a filter element of any one of Examples 51 to 57.

[0205] Example 59 is a method for filtering gas, the method comprising guiding gas through a filter medium of any one of Examples 1 to 55.

[0206] Example

[0207] The purpose and advantages of this disclosure are further illustrated by the following examples, but the specific materials and quantities described in these examples, as well as other conditions and details, should not be construed as unduly limiting this disclosure.

[0208] Test methods

[0209] Salt load test

[0210] Using a TSI 8130 workbench, with a concentration of 20 mg / m³ 3 NaCl salt particles (0.33 μm median diameter) loaded with 100 cm³ 2 Filter the media sample. Select a flow rate in the stage to represent real-world conditions. Adjust other stage settings to conform to the manufacturer's standards. As requested by the requester, select any point where the media load is from 4 inches to 10 inches of H2O (1000 Pa to 2500 Pa) before the end of the test, representing the pressure drop (dP). The stage measures the salt load, salt throughput, and dP across the media every minute. This data is recorded by the stage. Weigh the sample before and after the test; the difference in weight is the salt load, and this value is used to calibrate the photometer.

[0211] It has now been found that when loaded to a pressure drop increase of 2 inches of H2O at a medium velocity of 10 feet / minute (fpm) (5.33 cm / s), the pressure drop is greater than 0.5 g / ft. 2 (5.38g / m 2 The medium with a capacity of ) is a deep-loaded medium.

[0212] Modified ISO 11057 test method for filtration characterization of cleanable filter materials

[0213] To determine the pulse cleaning capability of the filter media, a modified version of the ISO 11057 test method for filtration characterization of cleanable filter media was used. The ISO standard has five stages. Stage 2 of the test was used, with the following modifications:

[0214] Main outrigger flow rate: 2.54m 3 / h;

[0215] Secondary outrigger flow rate: 5.07m 3 / h;

[0216] Maximum limit 1800Pa;

[0217] Dust feed rate: 2.0 g / m 3 ;

[0218] Pulse intensity: 0.1 MPa; and

[0219] 200 seconds per cycle, 300 cycles in total for each test.

[0220] All other test conditions remain unchanged.

[0221] For each cycle, record the pressure drop (dP) across the medium immediately following the pulse. Compare the performance of the pulse-cleanable medium using the final dP after 300 cycles and the dP extrapolated to after 3000 cycles. Extrapolation is performed using a logarithmic or power equation (choosing the equation with higher R0). 2 The curve of the data (up to 300 pulses) is fitted to the data, and then the equation is used to determine dP at 3000 pulses.

[0222] DEHS Efficiency Test

[0223] Tested at 100cm using a TSI 3160 worktable. 2 The efficiency of the media sample was measured under flow conditions representing real-world conditions, in this case using a flow rate of 4 feet per minute (fpm). An atomizer produced a distribution of DEHS droplets, and a differential mobility analyzer (DMA) was used to classify the DEHS droplet distribution into clouds of monodisperse particles. For this test, droplet sizes were 0.09 μm, 0.1 μm, 0.2 μm, 0.3 μm, and 0.4 μm. A cohesive particle counter (CPC) was then used to measure the challenge concentration upstream and downstream of the filtered sample to determine the media efficiency at those particle sizes. All other settings conformed to the manufacturer's specifications.

[0224] After determining the efficiency for all particle sizes, the system fits these points with a curve to determine which particle size is associated with the highest penetration rate (lowest efficiency). This is called the most penetrable particle size (MPPS) and can be the penetration rate calculated based on the fitted curve of the specific medium sample.

[0225] LEFS test

[0226] Cut a 4-inch diameter sample from the medium. Calculate the particle trapping efficiency of the test sample using 0.8 μm latex balls as the test challenge contaminant on a LEFS stage operating at 20 fpm (see ASTM Standard F1215-89 for a description of the LEFS test).

[0227] Example

[0228] Example 1

[0229] Laminated filter media were prepared using the following techniques. A 50 gsm wet-laid filter material comprising a mixture of glass fiber and bicomponent PET fiber was prepared, the filter material being similar to the filter material of Example 6 in U.S. Patent No. 7,314,497 (the modification being that it consisted of 40% B08 microglass fiber from Lauscha Fiber International, Lauscha, Germany and 60% TJ04BN bicomponent PET fiber from Teijin, Osaka, Japan). A 116 gsm wet-laid media consisting of a 90% cellulose and 10% polyester blend support material was purchased from H&V, East Walpole, MA, USA. Sheet properties are shown in Table 1.

[0230] Table 1

[0231]

[0232] The two layers are rolled up such that the glass bilayer is at the top and the cellulose polyester blend is at the bottom. Granular binder (Griltex 9E) from EMS-Griltech, Switzerland, is applied at a rate of 4.07 g / m³. 2 An amount of [amount] is applied between the two layers, and then they are heat-laminated at 265°F.

[0233] After lamination, a fine fiber layer is applied onto a 50 gsm glass bicomponent layer. This fine fiber layer consists of fibers with a size between 0.2 and 0.3 micrometers, and the fibers are composed of nylon with a LEFS efficiency of 82.4%.

[0234] The properties of flat sheets of laminated and coated nanofiber media were tested, and the voltage drop and efficiency of the components were tested using the EN1822 procedure. The results are shown in Table 2.

[0235] Table 2

[0236]

[0237] The flat sheet medium is pleated to a depth of 2 inches (5.1 cm) and integrated into a pair of 26-inch (66 cm) tapered and cylindrical filters. The tapered elements have 280 pleats / elements, while the cylindrical elements have 230 pleats. These elements are configured such that the nanofiber layers are upstream.

[0238] Example 2

[0239] Laminated filter media were prepared using the following techniques. A 50 gsm wet-laid filter material comprising a mixture of glass fiber and bicomponent PET fiber was prepared, the filter material being similar to the filter material of Example 6 in U.S. Patent No. 7,314,497 (the modification being that it consisted of 40% B08 microglass fiber from Lauscha Fiber International, Lauscha, Germany and 60% TJ04BN bicomponent PET fiber from Teijin, Osaka, Japan). A 116 gsm wet-laid media consisting of a 90% cellulose and 10% polyester blend support material was purchased from H&V, East Walpole, MA, USA. Sheet properties are shown in Table 3.

[0240] Table 3

[0241]

[0242] The two layers are rolled up such that the glass bilayer is on top and the cellulose polyester blend is on the bottom. The two layers are then heat-laminated at 265°F with a yield of 4.07 g / m³. 2 The amount of Griltex 9E granular binder from EMS-Griltech, Switzerland, was used between each layer. After lamination, a microfiber layer was applied onto a 116 gsm wet-laid cellulose polyester blend layer. This microfiber layer consisted of nylon fibers with a size between 0.2 and 0.3 micrometers, wherein the LEFS efficiency of the nylon fibers was 78%. The properties of flat sheets of the laminated and coated nanofiber media were tested. The results are shown in Table 4.

[0243] Table 4

[0244]

[0245] The flat sheet medium is pleated to a depth of 2 inches (5.1 cm) and integrated into a pair of 26-inch (66 cm) tapered and cylindrical filters. The tapered elements have 250 pleats / elements, while the cylindrical elements have 210 pleats. These elements are configured such that the nanofiber layer is upstream.

[0246] Example 3

[0247] Laminated filter media were prepared using the following technique. A 50 gsm wet-laid filter material comprising a mixture of glass fiber and bicomponent fibers was prepared, the filter material being similar to the filter material of Example 6 in U.S. Patent No. 7,314,497 (the modification being that it consists of 50% B08 microglass fiber from Lauscha Fiber International, Lauscha, Germany and 50% bicomponent PET fiber (TJ04BN) from Teijin, Osaka, Japan). 100 gsm spunbond support material, Finon C310NW, was purchased from Midwest Filter Materials, Cincinnati, Ohio, USA. The properties of the sheet are shown in Table 5.

[0248] Table 5

[0249]

[0250] The two layers are rolled up such that the wet-laid web layer is upstream and the spunbond layer is downstream. The two layers are then heat-laminated at 275°F with a lamination rate of 4.07 g / m³. 2 The amount of granular adhesive Griltex 9E (EMS-Griltech, Switzerland) is used between each layer.

[0251] The material is then wrinkled to an average depth of 0.027 inches (0.69 mm) (measured in the z-direction from the peak to the valley on the wire side of the medium), with 4.5 wrinkles per inch (1.77 wrinkles / cm). After wrinkling, a microfiber layer is applied onto a 50 gsm wet-laid layer. This microfiber layer consists of nylon fibers with a size between 0.2 and 0.3 micrometers, wherein the nylon fibers have a LEFS efficiency of 66%.

[0252] The flat sheet properties of the laminated, wrinkled, and coated media were tested. The results are shown in Table 6.

[0253] Table 6

[0254]

[0255] The flat sheet medium is pleated to a depth of 2 inches (5.1 cm) and integrated into a 26-inch (66 cm) cone and cylindrical filter pair. The cone element has 210 pleats / element, while the cylindrical element has 176 pleats. These elements are configured such that the nanofiber layer is upstream.

[0256] Example 4

[0257] The laminated filter media were prepared using the following techniques. An 18.6 gsm spunbond loose fabric layer, FINON C3019, was purchased from Midwest Filter Materials, Cincinnati, Ohio, USA. A 50 gsm wet-laid filter material comprising a mixture of glass fiber and bicomponent fibers was prepared, similar to the filter material of Example 6 in U.S. Patent No. 7,314,497 (the modification being that it consisted of 50% B08 microglass fiber from Lauscha Fiber International, Lauscha, Germany, and 50% bicomponent PET fiber (TJ04BN) from Teijin, Osaka, Japan). A 100 gsm spunbond support material, Finon C310NW, was purchased from Midwest Filter Materials, Cincinnati, Ohio, USA. The properties of the sheets are shown in Table 7.

[0258] Table 7

[0259]

[0260] The three layers are rolled up such that the loosely woven layer is upstream, the wet-laid web layer is in the middle, and the spunbond layer is downstream. The layers are then heat-laminated at 275°F with a lamination rate of 4.07 g / m³. 2 The amount of granular adhesive GRILTEX 9E (EMS-Griltech, Switzerland) is used between each layer.

[0261] The material is then wrinkled to an average depth of 0.0248 inches (0.63 mm) (measured in the z-direction from the peak to the valley on the wire side of the medium), with 4.5 wrinkles per inch (1.77 wrinkles / cm).

[0262] After wrinkling, a microfiber layer was applied to an 18.6 gsm spunbond loose fabric layer. This microfiber layer consisted of nylon fibers with a size between 0.2 and 0.3 micrometers, wherein the LEFS efficiency of the nylon fibers was 66%. The flat sheet properties of the laminated, wrinkled, and microfiber-coated medium were tested. The results are shown in Table 8.

[0263] Table 8

[0264]

[0265] Example 5

[0266] The laminated filter media was prepared using the following technique. A 50 gsm wet-laid filter material comprising a mixture of glass fiber and bicomponent fiber was prepared, the filter material being similar to the filter material of Example 6 in U.S. Patent No. 7,314,497 (the modification being that it is composed of 50% B04 microglass fiber from Lauscha Fiber International, Lauscha, Germany and 50% bicomponent PET fiber (TJ04BN) from Teijin, Osaka, Japan). 116 gsm wrinkled cellulose support material was purchased from H&V, East Walpole, MA, USA. The properties of the sheet are shown in Table 9.

[0267] Table 9

[0268]

[0269] The two layers are rolled up such that the wet-laid web layer is upstream and the cellulose wet-laid web layer is downstream. The layers are then heat-laminated at 275°F with a lamination rate of 4.07 g / m³. 2 The amount of granular adhesive Griltex 9E (EMS-Griltech, Switzerland) is used between each layer.

[0270] After lamination, a fine fiber layer is applied onto a 50 gsm wet-laid layer. This fine fiber layer consists of nylon fibers with a size between 0.2 and 0.3 micrometers, wherein the nylon fibers have a LEFS efficiency of 74%.

[0271] The properties of flat sheets of media that have been laminated and coated with fine fibers were tested. The results are shown in Table 10.

[0272] Table 10

[0273]

[0274] The flat sheet medium is pleated to a depth of 2 inches (5.1 cm) and integrated into a 26-inch (66 cm) cylindrical filter pair. The element has 250 pleats / elements. These elements are configured such that the nanofiber layer faces upstream.

[0275] Example 6

[0276] Laminated filter media were prepared using the following techniques. A 50 gsm wet-laid filter material comprising a mixture of glass fiber and bicomponent PET fiber was prepared, the filter material being similar to the filter material of Example 6 in U.S. Patent No. 7,314,497 (the modification being that it consisted of 40% B08 microglass fiber from Lauscha Fiber International, Lauscha, Germany and 60% TJ04BN bicomponent PET fiber from Teijin, Osaka, Japan). A 114 gsm wet-laid media composed of glass, polyester, and resin support materials was purchased from H&V Company, East Walpole, Massachusetts, USA. The properties of the sheet are shown in Table 11.

[0277] Table 11

[0278]

[0279] The EN933 material was wrinkled to an average depth of 0.0283 inches (0.72 mm) (measured in the z-direction from the peak to the valley on the wire side of the medium), with 4.5 wrinkles per inch (1.77 wrinkles / cm).

[0280] The two layers are then rolled up such that the glass bicomponent layer is on top and the glass polyester blend is on the bottom. The two layers are then heat-laminated at 265°F with a lamination rate of 4.07 g / m³. 2 The amount of Griltex 9E granular adhesive from EMS-Griltech in Switzerland is used between each layer.

[0281] Following lamination, a fine fiber layer was applied onto a 50 gsm wet-laid web. This fine fiber layer consisted of nylon fibers with a size between 0.2 and 0.3 micrometers, wherein the LEFS efficiency of the nylon fibers was 62.4%. The flat sheet properties of the laminated and coated nanofiber media were tested, and the results are shown in Table 12.

[0282] Table 12

[0283]

[0284] The flat sheet medium is pleated to a depth of 2 inches (5.1 cm) and integrated into a pair of 26-inch (66 cm) tapered and cylindrical filters. The tapered elements have 266 pleats / elements, while the cylindrical elements have 220 pleats. These elements are configured such that the nanofiber layers are upstream.

[0285] The full disclosures of the patents, patent documents, and publications cited herein are incorporated herein by reference in their entirety, as if they were individually incorporated. Various modifications and alterations to this disclosure will become apparent to those skilled in the art without departing from its scope and spirit. It should be understood that this disclosure is not intended to be overly limiting by the illustrative embodiments and examples set forth herein, and such examples and examples are presented by way of example only, wherein the scope of this disclosure is intended to be limited only by the claims set forth herein.

Claims

1. A gas filtration medium, comprising: A surface-loaded filter layer comprising fine fibers having an average diameter of less than 1 micrometer, wherein the surface-loaded filter layer has a density of less than 1 g / m². 2 The base weight; A deep-loaded filter layer comprising a high-efficiency filter layer comprising glass fiber and multi-component bonded fiber; wherein the deep-loaded filter layer exhibits a DEHS filtration efficiency of at least 55%; and wherein the deep-loaded filter layer exhibits a pressure rise of at least 1 g / m³ at pressures exceeding an initial value of 500 Pascals. 2 Salt loading capacity; as well as A support layer having a Gurley stiffness of 1000 mg or higher; Each layer is configured and arranged to be placed in the gas flow, wherein the surface-loaded filter layer is the upstream layer.

2. The filter medium according to claim 1, wherein the filter medium is pulse-cleanable according to a modified ISO 11057 test method.

3. The filter medium according to claim 1 further includes one or more additional layers, said additional layers including a surface-loaded filter layer, a depth-loaded filter layer, or a support layer.

4. The filter medium according to claim 1, 2 or 3, wherein the depth-loaded filter layer is positioned between the surface-loaded filter layer and the support layer.

5. The filter medium according to any one of claims 1, 2 or 3, wherein the deep-loaded filter layer comprises a high-efficiency melt-blown filter layer.

6. The filter medium according to any one of claims 1, 2 or 3, wherein the surface-loaded filter layer has a LEFS filtration efficiency of at least 30%.

7. The filter medium according to any one of claims 1, 2 or 3, wherein the depth-loaded filter layer has a density of up to 150 g / m³. 2 The base weight.

8. The filter medium according to any one of claims 1, 2 or 3, wherein the filter medium exhibits an efficiency of at least F9 according to EN779:2012.

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