Nanoparticle feed system for manufacturing filter media

Abstract

Systems, devices, and methods are provided for producing a product (e.g., a gas or liquid filter) that includes a filter media. A feed system for delivering nanoparticles includes: a container for receiving clusters of nanoparticles; and one or more vibrating elements coupled to the container and configured to pulse the nanoparticle clusters to convey the nanoparticle clusters through the container. The feed system also includes one or more components for converting the nanoparticle clusters into groups of nanoparticles having a smaller mass or volume than the nanoparticle clusters. The system simultaneously delivers and decomposes nanoparticle clusters such that they can be transported from a bulk bin to a filter manufacturing apparatus to form filter media, which improves quality and yield and reduces cost and time. In addition, the system is scalable and produces filter media with less discrepancy.

Description

Cross Reference to Related Applications

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 585,697, filed September 27, 2023, the entire disclosure of which is incorporated herein by reference for all purposes. TECHNICAL FIELD

[0002] The present specification generally relates to systems and methods for manufacturing products containing filtration media, such as gas or liquid filters, that incorporate nanoparticles into the filtration media. BACKGROUND

[0003] Filtration media is particularly useful in capturing contaminants in filtration devices due to the fine size of the fibers. The fibers of the filtration media are measured in microns and can be formed by spunbond, meltblown, electrospinning, or other techniques. As fluid flows through the filtration media, the fine fibers capture and entrap contaminants in the filtration media.

[0004] Contaminants range widely in size. However, contaminants smaller than 1 micron are the most harmful particles to the human body and are relatively difficult to filter. For example, traditional mechanical air filters typically report a MERV rating of the fibrous filtration material to be about 8-10. As such, these filtration media do not typically capture sub-micron particles, such as viruses and other harmful pathogens.

[0005] The filtration industry has focused on two different methods of capturing these sub-micron particles: electrostatic forces and the use of nanoparticles in the filtration media. Electrostatic filters are formed by electrostatically charging the fibers within the filtration media through the use of triboelectric methods, corona discharge, hydroelectric charging, electrospun fibers, or other known methods. Electrostatic filters are most effective at capturing sub-micron particles, are fairly effective at capturing 1 to 3 micron particles, and are least effective at capturing larger particles of 3 to 10 microns. Electrostatic fibers are commonly used in many filtration applications, such as masks and high efficiency filters, to filter sub-micron contaminants, such as viruses and the like.

[0006] Another method of capturing sub-micron contaminants is the use of nanoparticles in conjunction with the fibers. Filtration systems can employ filtration media that includes larger fibers measured in microns and smaller nanoparticles. The nanoparticles increase the surface area in the media for capturing particles by reducing the overall fiber size in the media. The nanoparticles also tend to pack against each other, thereby increasing the packing density within the filtration media. It has been shown that even a small amount of nanosized fibers in a layer formed on a microfibrous material improves the filtration properties of the material.

[0007] The most common method of incorporating nanoparticles into filtration media is by electrospinning a very thin layer of continuous nanofibers on a fibrous substrate. The nanoparticles typically extend parallel or perpendicular to the surface of the bulk filtration media layer and provide high efficiency filtration of small particles in addition to the filtration of larger particles provided by the coarse filtration media. For example, U.S. Patent No. 6,743,273 discloses a filtration media in which a continuous layer of nanofibers is deposited on the surface of a substrate. U.S. Patent No. 10,799,820 also discloses an air filtration media comprising a continuous layer of nanofibers on the surface of a filtration media.

[0008] While existing filtration media incorporating nanoparticles improves the relative efficiency of these filters, the commercial potential of these filters is still limited in certain applications because the nanoparticles are typically dispersed on the surface of the filtration media. The thin layer of nanoparticles on the surface of the filter provides only limited particle filtration and has a low dust holding capacity.

[0009] While many attempts have been made to incorporate nanomaterials into filtration media to improve overall filtration efficiency, these attempts have been limited to so-called “wet-laid” methods. These wet-laid methods involve incorporating chopped nanofibers into a liquid slurry to separate the entangled nanofibers with the help of surfactants. For example, U.S. Patent No. 10,252,201 discloses a filtration media made from a mixture of chopped nanofibers and chopped coarse fibers formed by a wet-laid method. Similarly, U.S. Patent Application Publication No. 2021 / 0023813 discloses a method of making a composite structure composed of a continuous nonwoven substrate with discontinuous fibers, such as carbon nanofibers. The method includes drawing the continuous fiber nonwoven substrate through a slurry of discontinuous fibers during which the nanomaterials are embedded into the nonwoven substrate.

[0010] While these structures have shown improved efficiency, they still suffer from other issues such as reduced longevity and / or efficiency as the media is subjected to normal use conditions. Furthermore, these wet-laid methods have not successfully incorporated nanoparticles uniformly throughout the nonwoven material, which results in clumping of the nanoparticles within the material, further reducing its efficiency and overall dust holding capacity. SUMMARY

[0011] The following presents a simplified summary of the claimed subject matter to provide a basic understanding of some aspects of the claimed subject matter. This summary is not an extensive overview of the claimed subject matter. It is not intended to identify key or critical elements of the claimed subject matter or to delineate the scope of the claimed subject matter. Its sole purpose is to present some concepts of the claimed subject matter in a simplified form as a prelude to the more detailed description that is presented later.

[0012] Systems, apparatuses, and methods for manufacturing products including filtration media are provided. The filtration media can include a substrate, such as a sheet, layer, membrane, apertured membrane, web, mesh, or other media. The substrate includes fibers and includes nanoparticles incorporated into at least a portion of the substrate.

[0013] In one aspect, a feed system for delivering nanoparticles includes a vessel for receiving clusters of nanoparticles and one or more components for converting each cluster of nanoparticles into a group of nanoparticles having a smaller mass or volume than the cluster of nanoparticles. The system also includes a conveyor for advancing the groups of nanoparticles and one or more vibratory elements for pulsing the nanoparticles.

[0014] The vibratory elements pulse the nanoparticles to break apart the clusters of nanoparticles within the vessel into smaller groups or agglomerations of nanoparticles or into individual nanoparticles. This allows the nanoparticles to disengage from the clusters and fall to the lower end of the vessel. The smaller groups or agglomerations of nanoparticles are then delivered through an opening at the lower end of the vessel and ultimately into a filtration media manufacturing device.

[0015] Nanoparticles are essentially weightless and easily suspended in air, making it more difficult to deliver them. In addition, the mechanical properties of nanoparticles do not allow them to freely fall in a tank or vessel for delivery. Instead, the nanoparticles stick to each other and adhere together, causing clumps to form over any type of opening. The vibratory elements described herein continuously and efficiently move the nanoparticles from the vessel to the manufacturing device without compressing and compacting the individual nanoparticles together, resulting in improved quality and yield of the filtration media formed and reduced costs and time. In addition, the system is scalable and produces filtration media with less variation.

[0016] In embodiments, the vibratory elements can have an amplitude of about 5 pounds force to about 500 pounds force, preferably about 75 pounds force to about 250 pounds force, and can oscillate at a frequency of about 2,000 Hz to about 15,000 Hz, preferably about 7,000 Hz to about 11,000 Hz. The vibratory elements can be located on the walls of the vessel and / or inside the vessel. The vibratory elements can be powered by any suitable means. In one embodiment, the vibratory elements include electromechanical devices powered by a DC power source. The vibratory elements convert the electrical current into pulses. In another embodiment, the vibratory elements are pneumatically driven by compressed air.

[0017] In one embodiment, the vibratory elements are disposed on the outer walls of the vessel and are configured to vibrate the walls of the vessel. This dislodges the nanoparticles from the vessel walls and allows them to fall through the lower opening in the vessel.

[0018] In embodiments, the system includes a bulk bin configured to open, separate, and / or break apart larger or large nanoparticle clusters / agglomerates into small nanoparticle clusters. The vessel includes a collection vessel positioned below the bulk bin opening for moving the nanoparticles from the bulk bin to an elevator that lifts and delivers the nanoparticles to a fiber manufacturing device.

[0019] In preferred embodiments, the collection vessel is shaped to control the volumetric or mass flow rate of nanoparticles therethrough. In one such embodiment, the vessel is substantially funnel shaped with a lower opening having a smaller cross-sectional area than an upper opening.

[0020] In embodiments, the bulk bin includes one or more rotors disposed within the bulk bin. Each rotor includes one or more rotating blades for mechanically separating the nanofiber clusters into smaller nanofiber groups or agglomerates, or into individual nanoparticles.

[0021] In embodiments, the rotors are configured to rotate about an axis transverse to the height of the vessel such that the blades transport the nanoparticles downward through the vessel to the underlying vessel and conveyor. In preferred embodiments, at least some of the rotors rotate in a clockwise direction and at least some of the rotors rotate in a counterclockwise direction. In certain embodiments, the bulk bin can include one or more rows of such rotors. In exemplary embodiments, the bulk bin includes a second, lower row of rotors for sweeping the nanoparticles off the side walls of the bulk bin.

[0022] In embodiments, the feed system includes an elevator coupled to the vessel for lifting the nanoparticles from a first height of the vessel to a second height greater than the first height. Nanoparticles are essentially weightless and readily suspended in air, making it more difficult to transport and / or lift them. In addition, the mechanical properties of the nanoparticles do not allow them to freely fall in a tank or vessel for transport. Instead, the nanoparticles will stick to each other and adhere together, resulting in agglomerates over any type of opening. The elevators described herein continuously and efficiently transport and lift the nanoparticles from the vessel or bulk bin to the manufacturing device without compressing and compacting the individual nanoparticles together.

[0023] In embodiments, the elevator includes an outer tube having a plurality of discs configured to move through the tube. The outer diameter of the preferred discs is sized to allow the discs to move through the tube while inhibiting the amount of space between the inner wall of the tube and the outer surface of the discs. This configuration defines interior compartments between the discs for containing and transporting the nanoparticle clusters.

[0024] The disc can be transported through the tube in any suitable manner. In one embodiment, the elevator comprises a cable coupled to the disc and a motor or other energy source coupled to the cable to translate the cable and disc through the tube. In other embodiments, the disc can be driven with pneumatic, electrical, magnetic, mechanical, or other suitable energy sources.

[0025] The tube preferably comprises one or more openings for allowing the nanoparticle clusters to enter and exit the compartment between the disc as it moves through the tube. This allows the elevator to transport the nanoparticle clusters from the container to the dispersion device. At least one opening is located above the tube to allow the nanoparticles to fall into the compartment, and at least one opening is located below the tube to allow the nanoparticles to fall out of the compartment. Alternatively, the tube can contain a rotatable internal section such that the compartment can be rotated from one orientation to another as the disc advances through the tube.

[0026] The tube can extend at an angle transverse to the vertical axis of the system to move the nanoparticles from a first height to a second height. In certain embodiments, the tube extends substantially parallel to the vertical axis.

[0027] In embodiments, the feed system comprises at least one feed bin or hopper disposed between the elevator and the dispersion device. The feed bin comprises a device for transporting the nanoparticles through the feed bin in a substantially horizontal direction and into the dispersion device. In exemplary embodiments, the device comprises an auger. The auger is used to further control the flow rate of the nanoparticles moving from the feed bin to the filter media manufacturing apparatus.

[0028] In embodiments, the feed system comprises a vessel disposed between the conveyor and the feed bin, the vessel configured to control the flow rate of the nanoparticles into the feed bin. The vessel preferably comprises a funnel shape, with a larger cross-sectional area of the upper opening aligned with the conveyor than the lower opening aligned with the feed bin.

[0029] In embodiments, the feed bin comprises one or more mechanisms for controlling the volumetric flow rate of the nanoparticles therethrough. In one embodiment, at least one of the mechanisms propels the nanoparticles through the feed bin in a substantially horizontal direction and into the dispersion device. In exemplary embodiments, the device comprises an auger comprising one or more curved vanes for redirecting the flow of the nanoparticles from a vertical direction to a horizontal direction and for controlling the volumetric flow rate of the nanoparticles from the feed bin to the filter media manufacturing apparatus.

[0030] In another aspect, a system for manufacturing filtration media is provided. The system includes a feeder for advancing a substrate comprising fibers from an upstream end to a downstream end. The system also includes a dispersion device for dispersing nanoparticles into the substrate to form the filtration media and a feed system for delivering the nanoparticles to the dispersion device. The feed system includes one or more vibrating elements for delivering clusters of nanoparticles to the dispersion device at a controlled rate.

[0031] The feed system is configured to separate and / or break the clusters of nanoparticles into smaller agglomerations of nanoparticles or individual nanoparticles that can be dispersed into the substrate. Further, the feed system delivers the nanoparticles to the dispersion device at a controlled rate or controlled volumetric flow rate, allowing them to be carried to a filter manufacturing apparatus to form the filtration media with improved quality and yield and reduced cost and time. Further, the system is scalable and produces filtration media with less variability.

[0032] In embodiments, the feed system delivers the nanoparticles at a rate that is substantially uniform with the rate at which the feeder advances the substrate from the upstream end to the downstream end. This ensures that a substantially constant amount of nanoparticles is dispersed into portions or sub-regions of the substrate, allowing the system to manufacture a relatively uniform filtration media, reducing variability between filtration media. The specific rate at which the nanoparticles are dispersed into the substrate will depend on the desired specifications of the final filtration product, such as a preferred mass of nanoparticles dispersed within a volume or square area of the filtration media. In exemplary embodiments, the nanoparticles are dispersed into the moving substrate at a rate of about 0.1 grams per square meter to about 10 grams per square meter, although it will be appreciated that this rate can vary depending on the specifications of the final product.

[0033] In another aspect, a filtration media is provided that is produced using one of the one or more systems described herein.

[0034] In another aspect, a gas or liquid filter is provided that is produced using one of the one or more systems described herein.

[0035] In embodiments, the filtration media manufacturing apparatus includes a first device for separating and / or isolating the nanoparticles in a gaseous medium and a second device for combining the nanoparticles with fibers to form a product comprising fibers and nanoparticles. The nanoparticles can be separated or isolated in any suitable gaseous medium (e.g., air, helium, nitrogen, oxygen, carbon dioxide, etc.) and dispersed into the product, substrate, or fiber stream by a gas flow, aerosol, vaporizer, spray, or other suitable delivery mechanism.

[0036] Separating and / or isolating individual nanoparticles in a gaseous medium and then dispersing them into a substrate allows for more uniform distribution of the nanoparticles throughout the product. In addition, the nanoparticles can be dispersed or distributed "at a depth" into the product. As used herein, the term "at a depth" means that the nanoparticles are dispersed beyond a first surface of the substrate, product, or other medium such that at least some of the nanoparticles are disposed between the first and second opposing surfaces in the internal structure of the substrate.

[0037] In certain embodiments, the product is a filtration medium and filter, such as an air filter, a face mask, a gas turbine and compressor intake filter, a panel filter, and the like. The nanoparticles increase the overall surface area of the filtration medium, which increases its filtration efficiency and allows for the capture of sub-micron contaminants without significantly compromising other factors, such as pressure drop (i.e., air flow) through the filter. In addition, the filters produced with the systems and methods described herein are able to withstand rigorous regulation, which allows the filters to achieve the same level of filtration performance throughout the life of the filter.

[0038] In one particular aspect, the first device includes a fiberizing device disposed between the feed system and a suitable dispersing device. As used herein, the term "fiberizing" means transforming (e.g., opening, separating, isolating, and / or individualizing) the clusters, agglomerates, or other groups of nanoparticles into individual nanoparticles having a size of less than 1 micron in at least one dimension.

[0039] In one embodiment, the second device includes a nozzle or similar device for dispersing the individual nanoparticles onto a first surface of a substrate comprising fibers such that the nanoparticles at least penetrate through the first surface of the substrate. The nozzle is preferably configured to disperse the nanoparticles at a depth into the substrate. In certain embodiments, the nozzle disperses the nanoparticles throughout substantially the entire medium from the first surface to an opposing second surface. In other embodiments, the nozzle disperses the nanoparticles within a portion of the medium from the first surface to a location between the first and second surfaces. In other embodiments, the nozzle disperses the nanoparticles at a density gradient from the first surface to the opposing second surface of the substrate. The density of the nanoparticles can be greater at the first or second surface.

[0040] The second device can also include a source of negative pressure or vacuum disposed below the substrate, opposite the nozzle, to increase the depth and uniformity of penetration of the nanoparticles. The source of negative pressure can be any suitable suction device that draws the nanoparticles through the substrate, such as a suction pump or the like.

[0041] The second apparatus can also include a feeder for advancing the substrate from the upstream end to the downstream end. The nozzle is preferably disposed between these two ends to disperse the nanoparticles onto the substrate. In certain embodiments, the feeder can also include a support surface extending between the two winders for supporting the substrate as it moves downstream through the system. In other embodiments, the substrate is unwound directly from the unwinder to the winder without another support surface.

[0042] The second apparatus can also include a coating device for dispersing an adhesive into the substrate on the fibers. The adhesive can comprise a variety of conventional materials, including natural materials (e.g., starch, dextrin, guar gum, etc.) or synthetic resins (e.g., EVA, PVA, PVOH, SBR, polyglycolide, etc.). In some embodiments, the substrate includes its own adhesive composition. In these embodiments, the substrate can or can not be added to with an adhesive. In one such embodiment, the substrate comprises bi-component fibers, with one component comprising an outer sheath at least partially surrounding an inner core.

[0043] The coating device can include any suitable device for dispersing the adhesive throughout the substrate. In one embodiment, the coating device includes a spray device having an outlet proximate the upstream end of the feeder and the nozzle. The sprayer can be located downstream of the fiberization device so that the adhesive can be sprayed after the nanoparticles are deposited. In other embodiments, the system can include two sprayers: one located upstream of the fiberization device, and a second sprayer located downstream of the fiberization device to coat the substrate with a second adhesive after the nanoparticles are deposited.

[0044] The second apparatus can also include a source of negative pressure or vacuum disposed below the substrate, opposite the sprayer, to increase the depth and uniformity of penetration of the adhesive. The source of negative pressure can be any suitable suction device for drawing the adhesive through the substrate, such as a suction pump or the like.

[0045] The second apparatus can also include a dryer, such as an IR oven or the like, disposed proximate the downstream end of the feeder for heating the nanoparticles and fibers to bind the nanoparticles to the fibers within the substrate.

[0046] The fiberization device can include a source of gas, such as compressed air or other suitable gas source, and a pump for drawing the smaller clusters of nanofibers out of the separator through a passageway into the device. The source of compressed air provides a motive fluid that circulates the nanofibers throughout the fiberization device and eventually out into the nozzle. The pump can include any suitable pump, such as a positive displacement pump, centrifugal pump, axial flow pump, or the like. In one embodiment, the pump includes an eductor configured to create sufficient negative pressure so that the small clusters of nanofibers are drawn out of the separator and through the passageway into the pump.

[0047] The system can also include an energy source, such as a second pump, a second jet, or the like, coupled to the first jet and configured to push the small clusters of nanofibers from the first jet toward the surface at a sufficient velocity to break the nanofibers and convert at least some of the small clusters of nanofibers into individual nanoparticles. Applicants have found that pushing the nanofibers toward a suitable surface at a velocity of about 500 feet per minute (fpm) to about 10,000 fpm, preferably about 2,000 fpm to about 6,000 fpm, is sufficient to break at least some of the nanofibers into individual nanoparticles.

[0048] The surface can be any surface that impedes the flow of nanofibers through the channel, such as an interior wall at a junction, or other redirecting interior wall, such as a curved surface, a perpendicular surface, or the like. Alternatively, the channel can include a wall or other surface disposed within the channel or projecting into the channel in the fluid path. In one embodiment, the channel extends to a substantially T-shaped junction, which includes two separate channels extending from the junction. The second jet is configured to push the nanoparticles toward the wall of the T-shaped junction at a velocity sufficient to break up at least some of the nanofibers.

[0049] In certain embodiments, the fiberization device further includes one or more reactors for separating individual nanoparticles that have been isolated from clusters of nanofibers that have not yet fully broken down. The reactors include a housing coupled to the channel and having an interior chamber and a source of negative pressure configured to draw smaller clusters of nanofibers away from the individual nanoparticles.

[0050] In embodiments, the reactors each include a rod or tube extending through the interior chamber and one or more inlets positioned at one end of the interior chamber and substantially surrounding the tube, which in some embodiments can substantially extend through the center of the interior chamber. The inlets are coupled to the one or more channels such that the clusters of nanofibers and individual nanoparticles are drawn into the chamber through the one or more inlets. The central tube includes an opening at an end opposite the one or more inlets. The opening is coupled to an internal channel within the tube and has an outlet coupled to a nozzle or other dispersal device. This allows the nanoparticles to enter the reactor through the inlets, then into the tube and into the dispersal device.

[0051] The inlets can be oriented at an angle relative to the central tube such that the nanofibers and nanoparticles enter the inner chamber at a transverse angle relative to the outer surface of the reactor. In preferred embodiments, at least one or more inlets are oriented such that when the nanofibers and nanoparticles enter the reactor, they move in a direction that is substantially tangential to the central tube. Once the nanofibers and nanoparticles enter the annular chamber surrounding the tube, their velocity vectors (speed and direction) create a vortex within the reactor that causes them to swirl around the central tube from one end to the other. Since individual nanoparticles are significantly lighter than the entangled nanofibers that are still clustered together, these individual nanoparticles are drawn into the inlets of the central tube. The vortex within the chamber can also further break down (e.g., open, separate, and / or individualize) the nanofiber clusters as they pass through the reactor.

[0052] The reactor can also include one or more outlets located on the opposite end of the one or more inlets. Larger and heavier nanofiber clusters that have not been broken down are drawn out through the one or more outlets. Thus, the isolated and individualized nanoparticles are drawn into the nozzle, while the nanofiber clusters are drawn out through the outlets. These outlets can be coupled to the first pump or the second pump, or to a further pump within the fiberization device that is designed to cause the nanofiber clusters to be further broken apart and recirculated back into the reactor.

[0053] The recitation of desirable objectives in this specification is not intended to mean or imply that any one or more of these objectives is a necessary feature, either individually or collectively, to the patent specification.

[0054] BRIEF DESCRIPTION OF DRAWINGS Figure 1 A system for manufacturing a filtration medium is schematically illustrated; Figure 2 A system for breaking down and / or isolating individual nanoparticles and dispersing the nanoparticles onto a substrate is schematically illustrated; Figure 3 An injector of the system of Figure 2 is illustrated; Figure 4 A reactor of the system of Figure 2 is illustrated; Figure 5 Another embodiment of a system for breaking down and / or isolating individual nanoparticles and dispersing the nanoparticles onto a substrate is illustrated; Figure 6 A system for manufacturing a dual-layer filtration medium is illustrated; Figure 7 is a schematic illustration of a feed system for delivering nanoparticles to one of the above filtration medium manufacturing systems; Figure 8is a more detailed view of the feed system of Figure 7 Figure 9 is a receptacle for receiving clusters of nanoparticles and introducing the nanoparticles to Figure 7 and Figure 8 is a partial cross-sectional schematic of a bulk bin in the feed system of Figure 10 is another schematic of the bulk bin of Figure 9 Figure 11 shows a rotor inside the bulk bin; Figure 12 is an enlarged view of a lower opening of the bulk bin showing a portion of an elevator configured to transport nanoparticles out of the bulk bin and lift them through the feed system; Figure 13 shows a portion of the elevator; Figure 14 shows another portion of the elevator; Figure 15 shows Figure 14 clusters of nanoparticles within the portion of the elevator shown; Figure 16 shows a receptacle for transporting nanoparticles from the elevator to a feed bin; Figure 17 is a schematic of the feed bin; Figure 18 is another schematic of the feed bin; Figure 19 shows an interior portion of the feed bin; Figure 20 is an enlarged view of the interior of the feed bin showing an auger for transporting nanoparticles out of the feed bin; Figure 21 shows another receptacle for transporting nanoparticles from the feed bin to a fiber manufacturing system; Figure 22 shows a fine flow control device for transporting nanoparticles into a fiber manufacturing device; Figure 23 shows a vibrating element for vibrating a receptacle to transport nanoparticles therethrough; Figure 24 is a side view of a filter medium having nanoparticles dispersed into a portion of the material; Figure 25 is a side view of a filter medium having nanoparticles dispersed throughout the material; Figure 26 is a side view of a filter medium having nanoparticles dispersed in the material in a gradient; ​​Figure 27 A dual layer filter media is shown; Figure 28 A filter media with a support layer is shown; Figure 29 A filter media with nanoparticles dispersed in a material at a depth and a scrim layer covering the nanoparticles is shown; and Figure 30 A dual layer filter media with nanoparticles dispersed on the inner surface of two layers is shown. DETAILED DESCRIPTION

[0055] This specification and the accompanying drawings show exemplary implementations and should not be considered limiting, the scope of which can be defined by the claims (including equivalents). Various mechanical, compositional, structural, and operational changes can be made without departing from the scope of this specification and the claims (including equivalents). In some instances, well-known structures and techniques have not been shown or described in detail in order not to obscure the disclosure. Identical numbers represent the same or similar elements throughout the two or more figures. Additionally, whenever possible, like reference numerals will be used throughout the drawings' description to refer to like elements. Moreover, any description set forth herein can encompass alterations, modifications and variations of the features discussed herein, as well as equivalents thereof. For instance, specific

[0056] It should be noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. As used herein, the term "includes" and its grammatical variants are intended to be non-limiting, such that recitation of items in a list of includes the possibility of other similar items not expressly listed.

[0057] Unless otherwise indicated, any quantitative value, unless otherwise indicated, is an approximation, and the recited quantity is intended to mean both amounts that are slightly above and below the stated amount. The materials, methods, and examples described herein are illustrative only and are not intended to be limiting.

[0058] Systems, devices, and methods for manufacturing products including filtration media and filters are provided. Filtration media and filters manufactured with the processes and methods described herein are also provided. The filtration media can include a substrate including at least one or more fibrous layers, such as a web, sheet, membrane, apertured membrane, mesh, netting, or other media. The one or more fibrous layers include one or more fibers and include nanoparticles incorporated into at least a portion of the at least one fibrous layer. The filters can include, but are not limited to, gas filters (e.g., HEPA and / or HVAC filters), liquid filters, gas turbine and compressor intake filters, panel filters, filter presses, membrane bioreactor membranes, hydrocarbon filters, diesel filters, fuel filters, hydraulic fluid filters, food and beverage filters, semiconductor filters, microfiltration membranes, downstream membrane filtration, pharmaceutical and medical filters (e.g., CPAP filters, face masks, etc.), wastewater filters, industrial process and / or municipal filters, gas turbine and compressor intake filters, panel filters, cartridge filters, bag filters, clean-in-place (CIP) filters, battery separators, and the like.

[0059] While the following description is primarily directed to filtration media and gas or liquid filters, it should be understood that the devices and methods disclosed herein can be readily adapted for a variety of other applications. For example, the filtration media disclosed herein can be used in household cleaning products, roofing and flooring products, automotive interior and headliner, reusable bags, wall coverings, filtration devices, insulation materials, and the like. Further, the individual nanoparticles isolated and generated in the methods described herein can be used in various coatings, composites, and / or additives, such as, for example, polymers, food packaging, flame retardants, fuel cells, batteries, capacitors, nanoceramics, lamps, materials manufacturing, production processes, reinforcements for composites, cement, and other materials, medical diagnostic applications, medical treatment devices or therapies, tissue engineering (e.g., scaffolds for bone or tissue repair), drinking water, industrial process fluids, food and beverage products, pharmaceutical and biological agents, tissue imaging, medical therapy delivery, environmental applications (e.g., biodegradable compounds), and the like.

[0060] Preferably, the nanoparticles have a size of less than 1 micron in at least one dimension (i.e., diameter, width, height, etc., depending on the cross-sectional shape of the fiber). In some embodiments, the nanoparticles comprise microfibers or nanofibers having a size of about 5 microns or greater in at least one dimension. For example, nanofibers having a diameter or width of less than 1 micron and a length of greater than 1 micron are nanoparticles as used herein. The nanoparticles can have a continuous length, or the nanoparticles can have a discrete length, such as 1 to 100,000 microns, preferably about 100 to 10,000 microns.

[0061] In certain embodiments, each individual nanoparticle can be a small particle having a size of about 1 to about 1000 nanometers, preferably about 1 to about 650 nanometers. In a number size distribution, at least half of the particles can be measured to have a particle size of 100 nanometers or less. Most nanoparticles are typically composed of only a few hundred atoms. When the size of a nanoparticle approaches the atomic scale, material properties change. This is due to the increased surface-to-volume ratio, which causes surface atoms of the material to dominate the properties of the material. Because of the very small size of nanoparticles, their surface-to-volume ratio is very large when compared to bulk materials, such as powders, plates, sheets, or larger fibers. This feature gives nanoparticles unexpected optical, physical, and chemical properties because they are small enough to confine their electrons and produce quantum effects.

[0062] The substrate can include a structure of individual fibers or threads that are interwoven, interlocked, or bonded together. For example, nonwoven fabrics can include a sheet or web structure that is bonded together by mechanically, thermally, or chemically entangling the fibers or filaments (and by perforating a film). They can be substantially flat, porous sheets made directly from individual fibers or molten plastic or plastic films. Examples of suitable nonwoven materials include, but are not limited to, fibers, layers, or webs that have been treated by meltblowing, spunbonding, or hydroentangling, thermal bonding, bonded carding, air-laying, wet-laying, coform, needle punching, stitching, hydro-entanglement, thermal bonding, or the like.

[0063] In certain embodiments, the substrate can comprise a knitted and / or woven material. The knitted material can include any knit pattern suitable for the desired application. Suitable knitted materials for filter applications include weft knit, warp knit, knitted mesh, compression knitted mesh, and the like. Suitable woven materials for filter applications include woven filter media, such as monofilament fabric, multifilament fabric, nylon mesh, polyester mesh, polypropylene mesh, and the like. Woven textiles, for example, can be used for mesh filter press cloths, woven filter pads and other die cuts, centrifuge filter bags, liquid filter bags, dust collector filter bags, bed dryer filter bags, rotary drum filters, filter belts, leaf filters, roll media, and the like.

[0064] In some embodiments, the filter media can include a structure comprising hybrid or entangled staple fibers and / or filaments. As used herein, staple fibers refer to fibers of limited length. As used herein, filaments refer to fibers having a substantially continuous length. In some embodiments, the substrate can include staple macrofibers, microfibers, and / or fine fibers. As used herein, "fine fibers" refer to fibers having a diameter of less than 1 micron, "macrofibers" refer to fibers having a diameter of greater than 10 microns, and microfibers refer to synthetic fibers having a diameter of less than 10 microns.

[0065] In certain embodiments, the nanoparticles are dispersed "at a depth" within the substrate. As used herein, the term "at a depth" means that the nanoparticles are dispersed past the first surface of the fibrous layer such that at least some of the nanoparticles are disposed between the first and second opposing surfaces in the internal structure of the filtration medium. In certain embodiments, the nanoparticles are dispersed throughout substantially the entire medium from the first surface to the opposing second surface. In other embodiments, the nanoparticles are dispersed within a portion of the medium from the first surface to some location between the first and second surfaces.

[0066] In some embodiments, the nanoparticles are spatially distributed in three dimensions relative to the support fibers, which can increase the fiber surface area and microvolumes within the filtration medium. The three-dimensional distribution can also prevent complete clogging of particular portions of the filtration medium, which is particularly useful in filtration media because it allows fluid (e.g., air and other gases) to pass through the filter, thereby reducing the overall pressure drop across the filter.

[0067] In other embodiments, the nanoparticles are disposed across the thickness of the fibrous layer in a density gradient such that the density of the nanoparticles disposed near one surface is higher than the opposing surface, or the density of the nanoparticles disposed on a surface is higher compared to the middle portion of the fibrous layer. The density gradient can be substantially linear, it can decrease in the form of a series of discrete steps, or the gradient can be random (i.e., the decrease in density is not generally linear or stepwise). Such a density gradient provides a number of advantageous features for certain applications (e.g., filters), as discussed below.

[0068] The nanoparticles can comprise any suitable material, such as glass, bioresorbable glass, ceramic materials, acrylics, carbon, metals (e.g., alumina), polymers (e.g., polyethylene, high-density polyethylene (HDPE), low-density polyethylene (LDPE) nylon, polyethylene terephthalate, polypropylene (PP), polybutylene (PBT), ethylene polyester (PET), polylactic acid (PLA), polyamide (PA), polyvinyl chloride (PVC), polyolefins, polyacetals, polyesters, cellulose ethers, polyalkylene sulfides, poly(arylene oxides), polysulfones, modified polysulfone polymers and polyvinyl alcohol, polyamides, polystyrene, polyacrylonitrile, polyvinylidene chloride, polymethyl methacrylate, polyvinylidene fluoride, and any combination thereof.

[0069] In some embodiments, the nanoparticles can be made into bi-component segmented pie and island shapes. The continuous filament nanoparticles are then drawn to obtain sub-micron filaments. The continuous filaments are cut to the desired length (preferably from about 100 to about 10,000 microns).

[0070] In some embodiments, the nanoparticles are absorbents and adsorbents. In some embodiments, the nanoparticles are activated carbon fibers or activated carbon powder. In some embodiments, the nanoparticles are catalytic particles or catalytic fibers. In some embodiments, the nanoparticles can be obtained by feeding the sub-micron fiber fibers into a pulverizer or crusher or trimmer, where the cohesive fibers enter and are chopped into short fibers. For example, a low weight bio-component meltblown or nanomeltblown fabric can be fed into a pulverizer, whereby sub-micron nanoparticles can be obtained.

[0071] In some embodiments, different nanoparticles can be mixed. For example, nanoparticles and nanobeads can be mixed. Two different nanoparticles with different melting points can also be mixed, such that the lower melting point nanoparticles can act as a binder for the higher melting point nanoparticles. Nanoparticles with different diameters and different lengths can also be mixed.

[0072] In some embodiments, the nanoparticles are selected from environmentally sustainable raw materials. The nanoparticles can include bioresorbable glass nanoparticles, biodegradable nanoparticles, compostable nanoparticles, or recyclable compositions.

[0073] Different types of nanoparticles can be combined. Some nanoparticles can be functional nanoparticles. For example, the functional nanoparticles can include activated carbon and / or antimicrobial materials deposited on and / or attached to the fibers in the filtration media. This can improve the gas absorption efficiency and germicidal efficacy of the fibers. In addition, the fiber products of the microfiber fibers with glass and carbon nanoparticles deposited thereon can provide filtration and deodorization functions as the filtration media.

[0074] In some embodiments, the nanoparticles are bound to the fibers via mechanical entanglement. This mechanical binding can be supplemented with adhesives or binders, as discussed in more detail below. In certain embodiments, the nanoparticles are not crimped (i.e., they do not include a pronounced wave shape, bend, crimp, coiled sawtooth, or similar shape associated with nanoparticles in a relaxed state). In other embodiments, the nanoparticles can have a discrete length of crimped structure. For example, when these nanoparticles with a discrete length of crimp are attached to the fibers, they entangle with each other and also firmly attach to, adhere on, and around the fibers, thereby forming modified fibers. In other embodiments, the attachment of the nanoparticles to the microfiber fibers is achieved via electrostatic charge attraction and / or van der Waals force attraction between the fibers and the nanoparticles.

[0075] Also provided are filters, such as gas and / or liquid filters, that include nanoparticles dispersed within the filter at a depth. In some embodiments, the filter includes one or more support layers that are adhered to a filtration medium. The support layers and / or filtration medium can include nanoparticles dispersed within the layers at a depth. In some embodiments, a polymeric layer, film, or membrane is provided that includes one or more pores for gas or liquid to flow therethrough, wherein nanoparticles are disposed within the polymeric layer at a depth. In other embodiments, the filtration medium includes a flexible surface layer for use in finger bandage pads, face masks, and the like.

[0076] Provided herein are systems, devices, and methods for producing filtration media and products containing the filtration media (e.g., gas or liquid filters). Also provided are systems and methods for isolating individual nanoparticles in a gaseous medium, such as air, helium, nitrogen, oxygen, carbon dioxide, and the like (as opposed to a liquid), and that are capable of being dispersed into another product, film, layer, or substrate via a gas stream, aerosol, vaporizer, spray, or other suitable delivery mechanism.

[0077] Figure 1 An entire system 110 for manufacturing the filtration media and other products described herein is schematically illustrated. As shown, the system 110 includes a feeder 120 for advancing a layer 130 of fibers or other material through the manufacturing process. The system 100 also includes a coater 140, a nanoparticle dispersion system 150, and a heating and / or drying device 160. In certain embodiments, the system 100 also includes a vacuum or other source of negative pressure 170 positioned below the substrate 130, opposite the fiberization system 150.

[0078] In one embodiment, the feeder 120 includes a winder 122 at the downstream end of the process and an unwinder 124 at the upstream end that continuously winds the layer 130 of fibers through the system 100. In certain embodiments, the feeder 120 can also include a support surface (not shown) that extends between the winder and the unwinder for supporting the layer 130 of fibers as it moves downstream through the system 100. In other embodiments, the layer of fibers is unwound directly from the unwinder 124 to the winder 122 without another support surface.

[0079] The coater 140 is configured to spray droplets of an adhesive or binding material (e.g., glue or cement) onto the fiber layer 130 so that the nanoparticles can adhere to the fibers within the layer 130 to form a stable matrix. The adhesive is preferably present in a relatively small amount to bind individual nanoparticles to the fibers throughout the layer 130. In a preferred embodiment, the coater 140 includes a nozzle sized to generate glue droplets having a diameter of about 20 to 30 microns to increase the depth of penetration of the glue through the layer 130. Of course, the droplet size can be influenced by a number of other parameters, including air pressure, air volume, air temperature, humidity, spray horn design, rheology / viscosity of the glue, carrier, etc.

[0080] Of course, it should be recognized that coating the substrate with an adhesive or binding material can be accomplished with other coating methods, including ultrasonic spray, dip coating, spin coating, gravure coating, kiss-roll coating, screen coating, powder coating, electrostatic, sputter coating, or similar coating techniques.

[0081] The adhesive can include a variety of conventional materials, including natural materials (e.g., starch, dextrin, guar gum, etc.) or synthetic resins (e.g., EVA, PVA, PVOH, SBR, etc.). In certain embodiments, a solvent-based glue is used, where adhesion occurs upon evaporation of the solvent.

[0082] In one preferred embodiment, the adhesive includes dextrin. In another embodiment, the adhesive includes a combination of a variety of substances (e.g., water, 2-hexyloxyethanol, isopropyl alcohol amine, sodium dodecylbenzenesulfonate, laurylamine oxide, and ammonium hydroxide). In yet another embodiment, the adhesive includes PVOH. The adhesive can be a solution, emulsion, suspension, hot melt, curable, pure substance, and / or combinations thereof.

[0083] In some embodiments, a glue resin is used, and the glue resin can be cross-linked after the glue is applied to the fiber layer 130. Adhesion (water resistance / solvent resistance) can be facilitated by self-cross-linking upon evaporation of the solvent in the glue formulation or thermal activation during the drying process. For certain glues, cross-linking can be achieved by electromagnetic radiation of high energy wavelengths, including but not limited to RF, UV, or electron beam. The amount of glue can be controlled by adjusting the nozzle size of the spray coater 140 or controlling the flow rate of the glue composition.

[0084] In some embodiments, the binder can include a surfactant to reduce the surface or interfacial tension of the binder, thereby increasing its dispersibility and wettability, and making the binder more easily penetrate to a certain depth in the substrate. Suitable surfactants for use with the binders disclosed herein include nonionic, anionic, cationic, and amphoteric surfactants, such as sodium stearate, 4-(5-dodecyl)benzenesulfonate, sodium dodecylbenzenesulfonate wetting agent, docusate (sodium dioctyl sulfosuccinate), alkyl ether phosphates, benzalkonium chloride (BAC), perfluorooctanesulfonate (PFOS), and the like.

[0085] In some embodiments, the spray machine 140 is located upstream of the nanoparticle dispersion system 150 so that the binder is sprayed prior to deposition of the nanoparticles. In other embodiments, the spray machine 140 is located downstream of the system 150 so that the binder can be sprayed after deposition of the nanoparticles. In other embodiments, the system 100 includes two spray machines; one located upstream of the system 150, and a second spray machine (not shown) located downstream of the system 150 to coat the fibrous layer 130 with a second binder after deposition of the nanoparticles.

[0086] In some embodiments, each spray machine 140 has more than one nozzle head. For example, the nozzle heads can be arranged in series to obtain better uniformity or to increase the fiber spray width. Alternatively, the nozzle heads can be placed in parallel (i.e., across the width of the substrate) to ensure that the binder is coated over the entire width of the substrate.

[0087] In preferred embodiments, a negative pressure source or vacuum source (not shown) is arranged below the fibrous layer 130, opposite the spray machine 140, to increase the penetration depth and uniformity of the binder. The negative pressure source can be any suitable suction device that draws the binder through the substrate, such as a suction pump or the like.

[0088] In some embodiments, the fibrous layer comprises its own binder composition. In these embodiments, the fibrous layer can or can not be added to a binder. In one such embodiment, the fibrous layer comprises a bi-component fiber, wherein one component comprises an outer sheath at least partially surrounding an inner core. In certain embodiments, the sheath and core can be substantially concentric with one another. In other embodiments, the core can be non-concentric with the sheath. In other embodiments, the core and sheath can be arranged side-by-side with one another. Of course, other configurations are possible. For example, the core can comprise a shape other than circular, such as dog bone, square, triangle, diamond, and the like. Alternatively, the fiber can comprise multiple cores, or can be divided into three, four, or more quadrants.

[0089] The sheath can comprise a material that adheres to the nanoparticles. For example, the sheath can comprise a material that becomes sticky and / or flowable upon heating and / or drying. During the heating / drying step, the sheath portion of the fiber is heated to its melting point until it becomes sticky and / or flowable to adhere the nanoparticles to the fiber layer. In preferred embodiments, the adhering and drying are performed simultaneously within the drying device 160.

[0090] Figure 2 A nanoparticle dispersion system 150 (or fiberization system) for converting nanoparticle groups into individual nanoparticles is schematically illustrated. As used herein, the term "fiberization" refers to the conversion (e.g., opening, separating, isolating, and / or individualizing) of clusters, agglomerates, or other groups of nanoparticles, which can or can not be entangled with one another, into individual nanoparticles having a size of less than 1 micron in at least one dimension. The dispersion system 150 converts large entangled nanoparticle clusters into smaller entangled nanoparticle clusters and then into individual nanoparticles.

[0091] As shown, the system 150 includes a feeder 200, such as a hopper, for introducing larger or large nanoparticle clusters / agglomerates into the system 150. The feeder 200 can include any suitable hopper device known to those skilled in the art and is preferably configured to introduce the large particle clusters into the process at a specified rate, which will depend on the fiberization rate downstream. The nanoparticles can be introduced continuously at a specified rate or at specified intervals. The bundled large nanoparticle clusters can be broken apart prior to introduction into the feeder 200.

[0092] It is recognized that the nanoparticles can be introduced into the system 150 in a variety of different forms. For example, the original nanoparticles can be manufactured as long, separate fibers. In this form, the nanoparticles can be cut to achieve the desired aspect ratio.

[0093] The system 150 also includes a separator 210, such as a blender or the like, for separating or breaking apart the large nanoparticle clusters / agglomerates into smaller nanoparticle clusters / agglomerates. The feeder 200 delivers the nanoparticles into the separator 210 in a steady, continuous stream by any mechanical means. The delivery rate will depend on a variety of factors, such as the speed at which the substrate 130 is advanced along the feeder 120, the fiberization rate of the nanoparticles, and the like. By controlling the amount of nanoparticles that fall into the separator 210, the amount of nanoparticles that are dispersed into the substrate can be controlled, thereby enabling a continuous manufacturing process.

[0094] In one embodiment, the separator 210 includes a housing 212 having a first opening 214 coupled to the feeder 200 and a second opening 216 coupled to a downstream process. The second opening 216 is preferably sized to only allow nanoparticle clusters of a certain size to pass. The separator 210 can include a plurality of rotatable vanes (not shown) designed to rotate about a vertical axis within the housing 212 to separate and open the coarse nanoparticle clusters. The vanes can have the same or different pitches and cambers to allow the entangled fibers to sequentially break apart or "open" as they are transferred from the first opening 214 to the second opening 216. One embodiment of the feeder 200 and separator 210 for a continuous manufacturing process is described below in Figures 7-13

[0095] The system 150 also includes a gas flow (discussed in greater detail below) that extends throughout the system from the separator 210 to the nozzle 220. The gas flow (along with a series of pumps discussed below) provides the motive force to move the nanoparticles through the system 150. In one embodiment, the gas flow is generated by an air compressor 230 configured to supply compressed air to the system, although it should be recognized that other forms of gas can be used to transport the nanoparticles through the system 150.

[0096] The system 150 includes one or more pumps for moving the nanoparticle clusters and ultimately the individual nanoparticles throughout the system. The pumps can include any suitable pump, such as a positive displacement pump, a centrifugal pump, a axial flow pump, etc. In one embodiment, a first pump 240 includes a first inlet fluidly coupled to the air compressor 230 through a first passageway 242 and a second inlet fluidly coupled to the separator 210 through a second passageway 244. Compressed air is drawn into the first pump 240, which creates a negative pressure (e.g., vacuum) to draw the nanoparticle clusters from the separator 210 into the pump (discussed in greater detail below). The system 150 can also include a second pump 250 and a third pump 260 each fluidly coupled to an outlet of the first pump 240. Similarly, the second pump 250 and the third pump 260 create a negative pressure to draw the nanoparticle clusters through a third passageway 252.

[0097] In certain embodiments, the pump 240 includes an eductor 300. As Figure 3 ​As shown, each of the injectors 300 includes a motive fluid inlet 302 and a nanofiber inlet 304, which are coupled to an outlet 306 by a fluid passage 308. The fluid passage 308 includes a converging inlet nozzle 310, a diffuser throat 312, and a diverging outlet diffuser 314. High pressure, low velocity air is converted to low pressure, high velocity air, creating the pressure differential required for suction. Based on the Venturi effect and Bernoulli's principle, a primary fluid medium (e.g., compressed air) is used to create a vacuum to draw the nanofibers into the injector 300 and out through the outlet 306. The diameter of the injector 300 depends on the volumetric flow rate of the compressed air, the suction requirement, the pressure drop, and the fluid pressure of the compressed air.

[0098] Review Figure 2 The third channel 252 includes a junction 254 that divides the third channel 252 into two separate channels, each leading to the second pump 250 and the third pump 260. The junction 254 preferably includes a surface or wall arranged substantially perpendicular to the third channel 252, thereby forming a T-shaped intersection. The surface can be any surface that impedes the flow of nanofibers through the channel, such as an interior wall at the point of connection, or other redirecting interior wall, such as a curved surface, a perpendicular surface, etc. Alternatively, the channel can include a wall or other surface arranged within the channel or protruding into the channel in the fluid path. In one embodiment, the channel extends to a substantially T-shaped junction that includes two separate channels extending from the junction. The second injector is configured to draw the nanofibers into the T-shaped junction at a speed sufficient to break apart at least some of the nanofiber clusters.

[0099] As the nanofiber clusters move through the third channel 252, they are pushed toward the surface or wall by the negative pressure exerted by the second pump 250 and the third pump 260. The velocity of the nanofibers relative to the junction 254 creates collisions with sufficient kinetic energy to cause at least some of the nanofiber clusters to break apart into smaller nanofiber clusters and / or individual nanofibers having a size in at least one dimension of less than 1 micron.

[0100] To create the kinetic energy required to break apart the nanofiber clusters, air is propelled through the system 150 at a speed of about 500 feet per minute (fpm) to about 10,000 fpm, preferably about 2,000 fpm to about 6,000 fpm. The system 150 includes a sufficient amount of suction pressure, preferably at least about 20 psi. This suction pressure creates a total pressure of at least about 100 psi throughout the system.

[0101] In certain embodiments, the system 150 further includes a fourth fluid passage 262 and a fifth fluid passage 264 coupling the outlets of the second pump 250 and the third pump 260 to the reactor 270. As Figure 4As shown, reactor 270 includes a top surface 272, a bottom surface 274, and an interior annular chamber 276 extending from top surface 272 to bottom surface 274. Reactor 270 also includes a central tube 275 having an open upper inlet 278 and an outlet 280. Reactor 270 can also include one or more upper outlets 282. Reactor 270 can be coupled with an energy source (not shown) configured to create a vortex flow of the swirling gas within annular chamber 276. The energy source can include any suitable energy source, such as a pump, a compressor, an electric generator, etc. The swirling gas preferably flows around central tube 275 from the bottom to the top of reactor 270 to move the nanoparticle clusters and individual nanoparticles from bottom surface 275 upward to top surface 272.

[0102] In another embodiment, the vortex flow is created without a separate energy source. In this embodiment, nanoparticle clusters 290 and individual nanoparticles 292 enter reactor 270 through bottom inlets 284, 285, 286, 287. Inlets 284, 285, 286, 287 are angled upward to facilitate movement of the nanoparticles and nanoparticles around central tube 275. In a preferred embodiment, at least one or more of inlets 284, 285, 286, 287 are angled such that the nanoparticles and nanoparticles enter reactor 270 substantially tangential to central tube 275. Once the nanoparticles and nanoparticles enter annular chamber 276, their velocity vectors (speed and direction) create a vortex flow within reactor 270 that causes them to swirl around central tube 275 and upward to the upper portion of chamber 276. The swirling gas preferably flows around central tube 275 from the bottom to the top of reactor 270 to move the nanoparticle clusters and individual nanoparticles from bottom surface 275 upward to top surface 272. Nanoparticle clusters 290 and individual nanoparticles 292 are blown from the bottom of the reactor to the top without any interference. The vortex flow within chamber 276 can further break down (e.g., open, separate, and / or individualize) nanoparticle clusters 290 as they pass through reactor 270.

[0103] In some embodiments, reactor 270 can also be coupled with an energy source (not shown) configured to create a vortex flow of the swirling gas within annular chamber 276. The energy source can include any suitable energy source, such as a pump, a compressor, an electric generator, etc.

[0104] The system 100 can also include another pump or source of negative pressure coupled to the upper outlet 282. This negative pressure draws the fibers from the outlet 282 such that the fibers 290 exit the reactor 270. Since the individual nanoparticles 292 are significantly lighter than the entangled nanoparticles 290 that are still clustered together, these individual nanoparticles 292 are drawn into the upper inlet 278 of the central tube 275. At the same time, the larger and heavier clusters of nanoparticles 290 that have not yet been broken down are drawn from the upper outlet 284. The upper outlet 284 can be coupled to other pumps (not shown), or to the first pump 240. In this way, the clusters of nanoparticles 290 are re-fed into the process for further breakdown, thereby forming a re-feed system to further break down the remaining clusters of nanoparticles.

[0105] The outlet 280 of the central tube 275 is coupled to the nozzle 220 (see Figure 2 ). The individual nanoparticles 292 are drawn into the nozzle 220, where they are dispersed onto the substrate surface or into a stream of fibers (discussed below). The nozzle 220 can comprise any suitable nozzle known to those skilled in the art. In one embodiment, the nozzle 220 has multiple outlets whose outer dimensions are tailored to the dimensions (i.e., area) of the substrate passing below the nozzle 220. The nozzle 220 will disperse the nanoparticles onto the substrate at a rate driven by the pressure throughout the system.

[0106] In certain embodiments, the system 100 comprises more than one nozzle coupled to the outlet 280 of the reactor 270. The nozzles can be arranged in any suitable fashion (e.g., side-by-side, in series, in parallel, etc.) on the substrate.

[0107] It is recognized that the pump 240 or the pumps 250, 260 can directly feed the nanofiber / air mixture stream into the nozzle 220 (i.e., bypassing the reactor 270). In this embodiment, the pressure within the system is designed to generate sufficient kinetic energy to break down or open substantially all of the nanoparticles into individual nanoparticles, such that the reactor 270 is not needed to separate the nanoparticles from the larger clusters of fibers.

[0108] Referring now to Figure 5 Another embodiment of a nanoparticle dispersion system 320 will now be described. As shown, the system 320 includes a separator 325 for separating larger or large clusters of nanoparticles into smaller clusters of nanoparticles that will pass through the system 320. A first eductor 326 is coupled to the outlet of the separator 325 for drawing the nanoparticles from the separator 325 into the system 320. An air compressor (not shown) is also coupled to the eductor 326 to provide the motive fluid, as discussed above.

[0109] Similar to previous embodiments, the second and third injectors 330, 340 are coupled to the outlet of the first injector 326. Nanoparticles are drawn from the first injector 320 and pushed against the surface of the T-junction 350 to break down at least some of the nanoparticles into smaller clusters or individual nanoparticles.

[0110] Each of the second and third injectors 330, 340 has an outlet coupled to a further T-junction 360, 370. As before, the nanoparticles are pushed against the surface of the T-junction 360, 370 to further break them down. The T-junctions 360, 370 are each coupled to two fluid channels that enter the bottom 380 of the reactor. Thus, the bottom 380 of the reactor has four separate inlets 382, 384, 386, 388 for the passage of nanoparticles. Each of these inlets is preferably angled upward and located in opposite corners of the reactor. This allows the nanoparticles to enter a vortex flow in the reactor that then swirls upward to the upper portion 390 of the reactor.

[0111] As previously discussed with reference to Figure 4 The reactor includes an annular chamber with a central tube having an open upper end and a lower end coupled to a nozzle. Nanoparticles that have been sufficiently broken down into individual nanoparticles flow through the open upper end and into the central tube for dispersion through the nozzle. Heavier clusters of nanoparticles that have not yet broken down exit the reactor through one of four separate outlets 392, 394, 396, 398. Injectors 410, 420 provide the motive force for drawing the nanoparticles out of the reactor 400, as discussed above. The outlets 392, 394 are each coupled to the injector 410 through a T-junction 412, and the outlets 396, 398 are each coupled to the injector 420 through a T-junction 422. In this case, the nanoparticles flow from two channels into one channel as they pass through the junctions 412, 422.

[0112] The injectors 410, 420 are each coupled with a T-junction 430, 440. As previously discussed, the nanoparticles are pushed into the T-junctions 430, 440 to further break them down into individual nanoparticles. The T-junctions 430, 440 are then each coupled with the bottom 380 of the reactor 400 (through inlets 432, 434, 442, 444). This allows the nanoparticles to be returned to the reactor 400 for further processing. This process is continuously performed on each nanoparticle cluster until it is completely broken down into nanoparticles and passes through the central tube into the nozzle. As a final step, the individualized nanoparticles are sprayed from the nozzle onto any substrate or mixed with any fiber spinning stream. In this process, the suction force is up to 20 psi and the pressure is up to 100 psi.

[0113] In certain embodiments, the system 150 or 200 can include a separate control system that monitors the nanoparticles to determine when they are broken down into individual nanoparticles suitable for passing through the nozzle. The control system can, for example, simply monitor the pressure of the entire system to ensure that enough pressure is applied to the nanoparticles to break them down into nanoparticles. Alternatively, the control system can include various different sensors disposed within the system to detect characteristics of the nanoparticles, such as weight or size. The sensors can be disposed, for example, within the reactor 400 so that the control system can control various parameters of the reactor 400, such as the negative pressure applied to the outlets 392, 394, 396, 398, the speed of the vortex passing around the annular chamber, or the pressure applied to the central tube to draw the nanoparticles into the nozzle.

[0114] Figure 6 Another embodiment of a system 500 for manufacturing a multi-layer filtration media is shown. As shown, the system 500 includes first and second unwinders 502, 504 and a single winder 506 for winding the first and second substrates 510, 512 downstream of the system 500. As with the previous embodiment, the system 500 can also include a support surface (not shown) for each of the substrates 510, 512. The first and second unwinders 502, 504 are used to advance the first and second substrates 510, 512 into the process where they are joined together and then wound onto the single winder 506, as described below.

[0115] The system 500 includes first and second spray applicators 520, 522, each located downstream of the first and second unwinders 502, 504 for applying a binder to the first and second substrates 510, 512. The system 500 also includes first and second fiberization systems / devices 530, 532, located downstream of each of the spray applicators 520, 522. As discussed previously, the fiberization devices 530, 532 generate individual nanoparticles and disperse these nanoparticles onto the substrates 510, 512.

[0116] After the nanoparticles are dispersed into the substrates 510, 512, the two substrates are joined together at a joining point 540 so that they advance together downstream. The two substrates can be adhered to one another at this point, or they can simply be placed one on top of the other.

[0117] The system 500 also includes a heater / drying device, such as an IR oven 550, located downstream of the joining point 540 of the two substrates. The heating / drying device heats and dries the two substrates so that they adhere to one another and the nanoparticles adhere to the fibers within the substrates. The substrates can, for example, be laminated to one another.

[0118] In some embodiments, nanoparticles are dispersed in two substrates 510, 512. In one such embodiment, system 500 is designed such that the nanoparticles are dispersed through a first surface of each substrate. The substrates can then be joined together such that the first surfaces face each other. Alternatively, the first surfaces can face away from each other (i.e., the substrates are joined at a second opposing surface of each substrate). In yet another embodiment, the first surface of the first substrate is connected to the second surface of the second substrate.

[0119] Figures 7-22 An embodiment of a feed system 600 is shown for separating or breaking down larger clusters / agglomerates of nanoparticles into smaller clusters and / or individual nanoparticles, and then conveying these smaller clusters and / or individual nanoparticles to one of the aforementioned filter manufacturing systems. The feed system 600 is particularly suitable for introducing nanoparticles into a continuous manufacturing process at a controlled mass or volumetric flow rate (i.e., the amount, volume, or total mass of nanoparticles passing through the feed system 600 per unit time). Nanoparticles can be introduced continuously at a specified flow rate or intermittently at specific flow rates. The conveying speed will depend on various factors, such as the substrate 130 along the feeder 120 (see...). Figure 1 Factors such as the travel speed, the fibrosis rate of the nanoparticles, and the desired amount of nanoparticles dispersed in a substrate of a given area / volume can be considered. By controlling the quantity, mass, or volume of nanoparticles falling into the manufacturing system, the amount of nanoparticles dispersed in the substrate can be controlled, resulting in a continuous manufacturing process with improved quality and yield, as well as reduced cost and time. Furthermore, the system is scalable and produces filter media with minimal variation.

[0120] like Figure 7 and Figure 8 As shown, the feeding system 600 typically includes a container or bulk bin 602, such as a hopper, for receiving relatively large (i.e., large) clusters or bundles of nanoparticles, and a lifter 604 for elevating the nanoparticles to a dispersion system 606, which disperses the nanoparticles into the filter manufacturing system (as described above). Large clusters or bundles of nanoparticles may be partially broken up before being introduced into the bulk bin 602, and / or they may be partially or completely broken up and separated within the container 602. It should be appreciated that nanoparticles can be introduced into the feeding system 600 in a variety of different forms. For example, the raw nanoparticles can be fabricated as long, separated fibers, such as nanofibers, microfibers, etc. In this form, the nanoparticles can be cut to obtain a desired aspect ratio.

[0121] The bulk hopper 602 can be used as a separator, such as a mixer, to separate or break down large clusters / bundles of nanoparticles into smaller clusters / aggregates, or directly separate or break down into individual nanoparticles. In one embodiment, the bulk hopper 602 includes a plurality of rotatable screws or rotors 610 designed to rotate about an axis within the bulk hopper 602 to separate and open coarse nanoparticle clusters (see discussion in more detail below). Figures 9-12 ).

[0122] like Figure 9 and Figure 12 As shown, rotor 610 can also be used to drive individual nanoparticles downward toward opening 612 at or near the bottom of container 602. Individual nanoparticles behave differently from macroscopic objects. Because the mass of nanoscale objects is so small, the attractive force of gravity between objects of this size is very small. Therefore, gravity has little or no effect on these particles (i.e., gravity does not automatically pull them downward toward opening 612). Opening 612 is coupled to collector 620 (see...). Figure 7 This is used to collect the individual nanoparticles that have been broken in container 602 and send them to elevator 604 (discussed in more detail below).

[0123] like Figure 9 As shown, rotor 610 can be driven by an external motor 612. In one embodiment, motor 612 includes a rotatable drive shaft 614 coupled to a cable or pulley system 616. Each rotor 610 may be formed on a rotatable disk or shaft 618 coupled to the pulley system 616, such that rotation of the drive shaft 614 causes rotation of the rotor 610. In some embodiments, a single motor 612 will drive all rotors 610. In other embodiments, the system may include multiple motors, each independently driving one or more rotors 610. Motor 612 may include any suitable motor, such as a brushless DC motor, permanent magnet DC motor, stepper motor, linear motor, synchronous motor, electromagnetic induction motor, servo motor, PMDC brushed motor, shunt motor, series motor, compound motor, etc.

[0124] like Figure 10 As shown, each rotor 610 includes a plurality of individual blades 622 circumferentially spaced around a central hub 624. In one such embodiment, each hub 624 includes five individual blades 622 evenly spaced around the hub; however, it should be appreciated that the blades may include fewer or more than five individual blades. The blades 622 may have the same or different pitch and camber to allow entangled fibers to sequentially untangle or “open” as they pass through the bulk bin 602.

[0125] In exemplary embodiments, each central hub 624 is positioned such that its vanes 622 rotate about an axis that is transverse to the vertical axis extending through the bulk bin 602. In exemplary embodiments, this axis is substantially perpendicular to the vertical axis of the bulk bin 602. Thus, as clusters of nanoparticles pass downward through the bulk bin 602, the vanes 622 engage these clusters to separate them or break them up into smaller clusters / blocks of nanoparticles or directly into individual nanoparticles. The vanes 622 also serve to force or transport the nanoparticles downward through the bulk bin 602. The bulk bin 602 can include a single row of rotors 610 or multiple rows of rotors 610.

[0126] The rotors 610 can be configured to rotate in opposite directions, with some hubs 624 rotating counterclockwise and others rotating clockwise. Alternatively, all of the rotors 610 can rotate in the same direction, i.e., counterclockwise or clockwise. In exemplary embodiments, the container 602 includes a row of at least four rotors 610 that extend substantially parallel to one another across the horizontal axis of the container 602, with each alternate propeller rotating in the opposite direction of the adjacent propeller, as shown in Figure 10

[0127] As shown in Figure 8 and Figure 11 each central hub 624 of a rotor 610 preferably extends from one side 626 to the other side 628 of the bulk bin 602 and includes multiple sets of vanes 622 extending along its entire length. Each hub 624 can include two or more sets, 5 or more sets, 10 or more sets, 20 or more sets, or 40 or more sets of vanes extending along its length, depending on the overall size of the bulk bin 602. Each set of vanes is preferably spaced a suitable distance from one another to ensure that larger clusters of nanoparticles do not fall between the sets of vanes without contacting a vane.

[0128] In certain embodiments, the hubs 624 are staggered (vertically and / or horizontally) from one another along the width and / or depth of the bulk bin 602 (see Figure 11 ), such that each set of vanes 622 covers a different cross-sectional area of the interior of the bulk bin 602. In addition, the vanes 622 can be designed to overlap one another, such that one set of vanes on one hub extends through the gap between two sets of vanes of another hub 624. This ensures that clusters of nanoparticles located between two sets of vanes contact the vanes of different hubs.

[0129] In one embodiment, the container 602 includes a lower row of rotors 630 that are primarily used to sweep nanoparticles off the interior walls of the bulk bin 602 to drive them into the opening 612 (see Figure 9 and 10 ​For this purpose, rotor 630 preferably includes at least two rotating blades 632 surrounding a central hub 634. Hubs 634 preferably rotate in opposite directions, one hub rotating clockwise and the other counterclockwise, such that rotor 630 can sweep nanoparticles adhering to either side of container 602. Hub 634 preferably extends along an axis substantially perpendicular to the vertical axis of container 602, but it should be recognized that other embodiments are also contemplated. For example, bulk hopper 602 may include a plurality of rotors 630 positioned along the inner wall of bulk hopper 602 to sweep nanoparticles off these walls and drive them toward opening 612.

[0130] like Figure 7 As shown, the collecting vessel 620 has an upper opening coupled to the bulk hopper 602 and a lower opening connected to the lifter 604. The lower opening has a much smaller cross-sectional area than the upper opening, allowing the nanoparticles to "leak" downwards to control the flow rate of the nanoparticles through the system, as discussed in more detail below. Furthermore, the vessel 620 includes one or more mechanisms for conveying or driving the nanoparticles through it. In one embodiment, at least one of these mechanisms includes one or more vibrating elements 638 coupled to the vessel 620 (see [link to documentation]). Figure 23 The vibrating element 638 is used to convey nanoparticles through the vessel 620 and into the lifter 604. The vibrating element is also used to pulse the nanoparticles to break up those that tend to clump together within the vessel 620. This allows the nanoparticles to detach from these clumps and fall into the lifter 604.

[0131] The vibrating element may have an amplitude of about 5 to about 500 pounds of force, preferably about 75 to about 250 pounds of force, and may oscillate at a frequency of about 2,000 Hz to about 15,000 Hz, preferably about 7,000 Hz to about 11,000 Hz. The vibrating element may be located on the wall and / or inside the vessel 620. The vibrating element may be powered by any suitable means. In one embodiment, the vibrating element includes an electromechanical device powered by a DC power supply. The vibrating element converts current into pulses. In another embodiment, the vibrating element is pneumatically driven by compressed air.

[0132] Now for reference Figure 23Vibration elements 638 can be coupled to one or more outer walls 639 of collection vessel 620 (or any other vessel within feed system 600). In one embodiment, vibration elements 638 each include one or more attachment elements 641 for attaching an oscillator 643 to outer wall 639 and a connection element 645 for coupling vibration element 638 to a suitable power source. Vibration elements 638 are configured to vibrate the outer walls 639 of the collection vessel to pulse the nanoparticles and break apart those nanoparticles that are prone to clumping together into clumps within container 620. This allows the nanoparticles to break free from these clumps and fall into elevator 204.

[0133] Referring now to Figure 8 and Figures 13-15 , elevator 604 is used to lift nanoparticles that exit container 620 from a first height to a second height that is greater than the first height. Nanoparticles are generally unable to be transported because they have little or no weight. As a result, nanoparticles are prone to being pressed against each other and clump together at any type of opening. Elevator 604 overcomes these issues by transporting and lifting the nanoparticles from vessel 620 to dispersion system 606.

[0134] In certain embodiments, elevator 604 includes one or more transport tubes 640 that are used to transport the nanoparticles to a higher height without pressing them back into clumps. In certain embodiments, tubes 640 include at least one section that extends at a transverse angle to the vertical direction (see Figure 7 ). In other embodiments, tubes 640 include at least one section that is substantially parallel to the vertical direction (see Figure 8 ). Elevator 604 includes a plurality of disks 641 that are spaced apart from each other throughout tube 640. The diameter of disks 641 is generally permitted to pass through tube 640 (i.e., slightly smaller than the inner diameter of tube 640). In addition, the diameter of disks 641 is close enough to the inner diameter of tube 640 to define an internal compartment 642 between adjacent disks 641. Disks 641 are used to isolate the interior of compartment 642 as each compartment 642 is transported through tube 640.

[0135] Tube 640 extends from a lower opening (not shown) in collection vessel 620 to an upper opening 650 of a funnel-shaped transport vessel 652 in dispersion device 606. For reasons discussed below, vessel 652 is positioned above vessel 620, and therefore, tube 640 transports and lifts the nanoparticles from a first height to a second height that is greater than the first height.

[0136] The elevator 604 also includes a cable 644 within the tube 640 that carries the compartments 642 through the tube 640. In one embodiment, the cable 644 extends through each disc 641 within the tube 640 and is coupled to a suitable energy source for moving the cable 644 (and with it the discs 641) through the tube. The tube 640 can extend upwardly from the vessel 620 to the dispersion device 606 and then downwardly back to the vessel 620 (see Figure 7 ). The compartments 642 moving upwardly generally contain nanoparticles, and the compartments 642 moving downwardly are substantially free of nanoparticles. Alternatively, the tube 640 can be a continuous tube that moves in one direction.

[0137] Referring again to Figure 8 , the elevator 604 preferably includes a motor 649 coupled to the cable 644 for pushing the cable 644 through the feed system 600 in a direction such that the discs 641 are pushed in that direction. The motor 649 can include any suitable motor, such as a brushless DC motor, a permanent magnet DC motor, a stepper motor, a linear motor, a synchronous motor, an electromagnetic induction motor, a servo motor, a PMDC brush motor, a shunt motor, a series motor, a compound motor, etc.

[0138] The cable 644 can be coupled to one or more drive wheels that re-orient the cable 644 within the feed system 600. For example, as shown in Figure 8 , the cable 644 preferably extends substantially horizontally below the bulk bin 602 and is then re-oriented by a first drive wheel 651 into a vertical direction to lift the nanoparticle clumps. A second drive wheel 653 is used to re-orient the cable 604 into a substantially horizontal direction where the cable 604 passes over the vessel 652 to distribute the nanoparticles into the dispersion system 606.

[0139] The tube 640 includes one or more openings (not shown) that align with openings in the vessel 620 and the vessel 652 to allow the nanoparticles to enter the compartments 642 from the vessel 620 and exit the compartments 642 into the vessel 652. In certain embodiments, the openings positioned adjacent to the vessel 620 are on the upper surface of the tube 640, and the openings positioned adjacent to the vessel 652 are on the lower surface of the tube 640. Alternatively, the tube 640 can have rotatable sections that allow the openings to move from one configuration to another. Thus, as a single compartment 642 passes through the openings below the vessel 620, nanoparticles can fall from the vessel 620 into the compartment 642. As the compartment 642 continues to move upwardly along the tube 642, the inner walls of the tube 642 and the discs 641 of the compartment 642 will enclose the interior of the compartment 642 such that the nanoparticles are trapped therein. This allows the nanoparticles to be transported along the tube without squeezing them into bundles or clumps.

[0140] Alternatively, the openings in the tubes 640 can be opened and closed. For example, the elevator 604 can include one or more actuators for opening and closing the openings in the tubes 640. The actuators can include any suitable mechanism, such as an electronic actuator, a pneumatic actuator, a mechanical actuator, etc. In certain embodiments, the system 600 further includes a controller (not shown) for automatically opening and closing the openings at the appropriate time or based on data obtained from the sensors (i.e., opening them as they pass under the vessel 620 and then closing them as they move upward toward the dispersing device 606). In other embodiments, the system 600 can be a mechanical element that cooperates with one another to automatically open and / or close the openings as they pass under the vessel 620 and the dispersing device 606.

[0141] Figure 15 Nanoparticle clusters 647 moved by the elevator 604 are shown. As shown, each nanoparticle cluster 647 is located within a compartment 642 between two disks 641 within a tube 640 of the elevator 604. As the disks 641 are pushed through the tube 640, the nanoparticle clusters 647 are pushed along with them.

[0142] Review Figure 8 The dispersing system 606 is used to control the rate or flow rate of nanoparticle delivery into the filter media manufacturing system. In particular, the dispersing system 606 ensures that an appropriate amount of nanoparticle is dispersed onto the fibers within the substrate. For example, the dispersing system 606 is configured to deliver nanoparticle at a particular mass or volume flow rate that is substantially uniform with the rate at which the feeder 200 advances the substrate from the upstream end to the downstream end. This ensures that a substantially constant amount of nanoparticle is dispersed into portions or sub-regions of the substrate, allowing the system to manufacture a relatively uniform filter media, reducing variability between filter media. The particular rate at which the nanoparticle is dispersed into the substrate will depend on the desired specifications of the final filtration product, such as the preferred mass of nanoparticle dispersed within a volume or square area of the filter media. In exemplary embodiments, the nanoparticle is dispersed into the moving substrate at a rate of about 0.1 grams per square meter to about 10 grams per square meter, although it will be appreciated that this rate can vary depending on the specifications of the final product.

[0143] The rate of advancement of the substrate will depend on a number of factors in the production process, including the desired amount of nanoparticle dispersed into the regions of the substrate. In one embodiment, the rate of advancement of the substrate is about 0.05 meters per second to about 1 meter per second.

[0144] The dispersing system 606 generally includes an upper hopper vessel 652 that collects the nanoparticle from the conveyor 604, a feed bin 660, and one or more lower hopper vessels 670. As Figure 8 and Figure 16As shown, the upper funnel-shaped vessel 652 has an upper opening 650 coupled to the opening in the tube 640 of the elevator 604 and a lower opening 655 coupled to the feed bin 660. The lower opening 655 has a much smaller cross-sectional area than the upper opening 653, such that the nanoparticles "leak" downward to control the flow rate of the nanoparticles through the system. Similar to the collection vessel 620, the vessel 652 can also include one or more vibrating elements that pulse the nanoparticles and prevent them from forming clumps. These vibrating elements can be located on the outer wall of the vessel 652, for example. Alternatively, the vibrating elements can be positioned within the vessel 652 to facilitate nanoparticle transport through the vessel 652.

[0145] Referring now to Figure 19 , the feed bin 660 includes a first opening 661 for receiving the nanoparticles from the vessel 652 and a second opening (not shown) for delivering the nanoparticles to the lower vessel 670. The feed bin 660 also includes one or more mechanisms inside the feed bin 660 to deliver the nanoparticles therethrough. As Figure 18 and Figure 19 shown, the feed bin 660 preferably includes one or more rotating drums 662 that extend through the interior of the feed bin 660. One or more rods 663 are coupled to the drums 662 and are configured to rotate therewith to sweep the nanoparticles downward through the feed bin.

[0146] Referring now to Figure 8 and Figure 20 , the feed bin also includes an auger 664 for moving the nanoparticles in a generally horizontal direction through the feed bin 660 to the lower vessel 670. In a preferred embodiment, the auger 664 includes a plurality of curved vanes 665 that function to receive clusters of nanoparticles that have fallen vertically into the feed bin 660 and re-orient these nanoparticles into a horizontal direction through the feed bin 660. The curved vanes 665 also function to control the volumetric flow rate of the nanoparticles through the feed bin 660 and into the filter manufacturing system. The auger 664 can be driven by any suitable motor 666, such as any of the motors described above.

[0147] Referring now to Figure 8 and Figure 21The lower vessel 670 has an upper opening 672 coupled to an opening in the feed bin 660 and a lower opening 676 coupled to the fiber manufacturing system described above. The lower vessel 670 preferably has a substantially funnel shape such that the lower opening has a smaller cross-sectional area than the upper opening to control the flow rate of nanoparticles therethrough. Similar to the collection vessel 620, the lower vessel 670 can include one or more vibrating elements that pulse the nanoparticles and prevent them from forming clumps. These vibrating elements can be located, for example, within the interior walls of the vessel 670. Alternatively, the vibrating elements can be positioned to facilitate the transport of nanoparticles through the vessel 670.

[0148] Reference will now be made to Figure 22 The feed system 600 can also include a fine flow control device 680 that receives the nanoparticles from the vessel 670 and provides final control over the volumetric flow rate of nanoparticles into the filter media manufacturing equipment. The flow control device 680 includes a funnel-shaped vessel 682 having an opening 684 for receiving the nanoparticles from the vessel 670 and a lower opening (not shown) coupled to a feeder tray 690. The feeder tray 690 includes a feed channel 692 that tapers toward an opening 693. The opening 693 can be coupled to any suitable filter media manufacturing equipment, such as any of the filter media manufacturing equipment described above, or other filter media manufacturing equipment as can occur to those skilled in the art.

[0149] Reference will now be made to Figures 24-30 A representative filter media that can be manufactured by any of the systems described above will now be described. Figure 24 A representative filter media or substrate 10 including a plurality of fibers 12 and nanoparticles 14 manufactured by the systems and methods described above is shown. The substrate 10 has a first surface 16 and a second surface 18 opposite the first surface 16, and defines a width or thickness between the first surface 16 and the second surface 18. The nanoparticles 14 have been deposited into the substrate through the first surface 16. As shown, the nanoparticles 14 penetrate through the first surface 16 into the substrate 10 to a "depth" between the first surface 16 and the second surface 18. In some embodiments, the nanoparticles 14 penetrate from the first surface to at least 25% of the width or thickness between the first surface 16 and the second surface 18, or more preferably to at least about 50% of the thickness. In other embodiments, the nanoparticles 14 substantially penetrate throughout the substrate 10 from the first surface 16 to the second surface 18.

[0150] The nanoparticles 14 preferably include individual nanoparticles that have been broken, separated, and isolated from one another prior to being dispersed into the substrate 10, as discussed above. In this way, the nanoparticles 14 are not present in the fibrous product in the form of a layer, and do not have distinct nanoparticles clumps or bundles. This allows the nanoparticles to be more dispersed throughout the substrate, which in some applications (e.g., gas or air filters) provides a more efficient filtering capability to filter out contaminants. In addition, this allows the nanoparticles in the filter media to have a greater areal density (in grams per square meter (gsm)) or "add-on" within the material. The term "add-on" is used herein to refer to the areal density (gsm) of a material, fiber, or particle in a thin layer, sheet, or film of the material.

[0151] In certain embodiments, the nanoparticles can comprise an add-on of about 0.1 grams / meter2(g / m2) 2 to about 20 grams / meter2(g / m2) 2 , preferably at least about 2.0 grams / meter2(g / m2) 2 The particular add-on or areal density can depend on the application. For example, Applicants have found that a higher areal density or add-on will increase the efficiency of the filter media to filter out contaminants. Thus, the particular add-on of the nanoparticles can depend on the desired efficiency of the filter media.

[0152] Figure 25 A filter media or substrate 20 comprising a plurality of fibers 12 and nanoparticles 24 made by the above-described systems and methods is shown. As shown, the nanoparticles 14 permeate throughout the entire width of the substrate 20 from the first surface 16 to the second surface 18. In certain embodiments, the nanoparticles 14 are substantially dispersed throughout the fibers 12 of the substrate, as shown. Figure 25 In certain embodiments, the difference in the density of the nanoparticles at the first surface 16 and the density of the nanoparticles dispersed within the central portion of the substrate 20 between the surfaces 16, 18 is less than 50%. In some embodiments, the difference is less than 25%, preferably less than 10%. In certain embodiments, the amount or number of individual nanoparticles dispersed within the central portion of the substrate 20 is at least about 50%, preferably at least about 75%, and more preferably at least about 90% of the amount of individual nanoparticles dispersed at or near the first surface 16.

[0153] In other embodiments, the nanoparticles 14 are arranged in a density gradient from the first surface 16 to the second surface 18. For example, Figure 26The substrate 30 is shown with a density gradient of nanoparticles 14, where the density of nanoparticles 14 disposed near the first surface 16 is higher than the density of nanoparticles 14 disposed near the second surface 18. In certain embodiments, the difference in density of nanoparticles at the first surface 16 and the density of nanoparticles dispersed at the second surface 18 is greater than about 75%. In some embodiments, the difference is greater than 50%. In some embodiments, the difference is greater than 25%. In certain embodiments, the amount or number of individual nanoparticles dispersed at or near the second surface 18 is less than about 50%, preferably less than about 25%, and more preferably less than about 10% of the amount of individual nanoparticles dispersed at or near the first surface 16.

[0154] Figure 25 The density gradient shown in FIG. 1 can be substantially linear from the first surface 16 to the second surface 18. Alternatively, the density of nanoparticles 14 can decrease from the first surface 16 to the second surface 18 in the form of a series of discrete steps, or the gradient can be random (i.e., the decrease in density is not generally linear or stepwise).

[0155] In other embodiments, nanoparticles can be added to the substrate from both the first and second surfaces 16, 18. In these embodiments, the areal density or "add-on" at the first surface 16 and the second surface 18 can be substantially equal to each other, or they can differ depending on the application. In these embodiments, the areal density or "add-on" in the middle of the substrate is lower than the areal density or "add-on" at the surfaces 16, 18. For example, the areal density in the middle of the substrate can be about 75% of the areal density at the surfaces 16, 18, or it can be about 50%, 40%, or 25%.

[0156] The distribution of nanoparticles across the thickness of the filter media can be measured, for example, using imaging techniques. Using a magnified view of the fibrous product taken at a horizontal cross-section of the product in the middle of the product thickness, using an electron microscope or other technique, this can be compared to images taken at the upper or lower surface of the product, or all three images can be compared to determine the degree of variation in the amount of nanoparticles deposited. Computer image analysis can be employed. For example, in Figure 25At the same time, a cross-section can be taken at line A-A, and a cross-section can be taken at line B-B. A top view of each cross-section can be obtained by electron microscopy, scanning electron microscopy, and other microscopy. For example, the top view of the cross-section obtained at cross-section A-A can be compared to the top view obtained at cross-section B-B. The number of microfibers, the number of nanoparticles, or both in the same two-dimensional dimension of the sample can be evaluated and compared. In addition, imaging techniques can be used on the three-dimensional sample. These techniques can be used to evaluate the orientation of the fibers and other characteristics. These techniques can be used to determine whether the nanoparticles have been deposited to a certain depth in the substrate, have been substantially deposited in a majority of the substrate, have been substantially deposited throughout the depth of the substrate, or have been deposited to a certain partial depth of the substrate.

[0157] The fibers of the contemplated substrates can be manufactured by any method, including but not limited to thermal bonding, cellulose wetlaying, glass wetlaying, synthetic wetlaying, composite wetlaying, needle punching, meltblowing, air-laying, spinnerets, gel spinning, melt spinning, wet spinning, dry spinning, island-in-the-sea staple or spunbond, segmented pie staple or spunbond, and the like. Such methods are described in U.S. Pat. Nos. 4,406,950; 6,338,814; 6,616,435; 6,861,142; 7,252,493; 7,300,272; 7,309,430; 7,422,071; 7,431,869; 7,504,348; 7,774,077; 9,522,357; 9,993,761; and U.S. Patent Publication No. 2009 / 266,759, the entire disclosures of which are incorporated herein by reference for all purposes.

[0158] The contemplated fibers can have a variety of cross-sectional shapes, including but not limited to circular, kidney bean, dog bone, trilobal, dumbbell, bowtie, star, Y-shaped, and the like. These shapes and / or other conventional shapes can be used in various embodiments to obtain desired performance characteristics. The fibers in the substrate are held connected to one another by thermal bonding, chemical bonding, entanglement with one another, use of a bonding agent such as an adhesive, and the like.

[0159] The fibers can be man-made or natural fibers. Suitable materials for the fibers include, but are not limited to, metal fibers, carbon fibers, polypropylene (PP), polyester (PET), PEN polyester, PCT polyester, polybutylene (PBT), ethylene polyester (PET), polylactic acid (PLA), polyamide (PA), co-polyamides, polyethylene, high density polyethylene (HDPE), low density polyethylene (LLDPE), cross-linked polyethylene, polycarbonate, polyacrylate, polyacrylonitrile, polyfumaronitrile, polystyrene, styrene maleic anhydride, polymethyl pentene, cyclic olefin copolymer or fluorinated polymer, polytetrafluoroethylene, perfluoroethylene and hexafluoropropylene or copolymers (such as P(VDF-TrFE)) or terpolymers (such as P(VDF-TrFE-CFE)) with PVDF, propylene, polyimide, polyether ketone, cellulose ester, nylon and polyamide, polymethacrylic acid, poly(methyl methacrylate), polyformaldehyde, polysulfonate, acrylic acid, styrenated acrylic acid, pre-oxidized acrylic acid, fluorinated acrylic acid, vinyl acetate, vinyl acrylic acid, ethylene vinyl acetate, styrene-butadiene, ethylene / chloroethylene, vinyl acetate copolymer, latex, polyester copolymer, carboxylated styrene acrylic or vinyl acetate, epoxy, acrylic multipolymer, phenol formaldehyde, polyurethane, cellulose, styrene, or any combination thereof. Other conventional fiber materials are also contemplated.

[0160] The fibers can include fibers of different sizes, with the fibers typically having a diameter of about 1 to about 1000 microns and a length of about ½ to 3 inches. The fibers can be configured as a gradient density media, with the pore size decreasing from the upper surface (upstream) to the lower surface (downstream) of the filter to increase capture efficiency and dust holding capacity. This configuration also allows for different amounts of nanoparticles to be dispersed into different depths of the filtration media. For example, the upstream side of the filtration media can have the largest fiber size to allow for more void space and a greater nanoparticle density, while the downstream side of the filtration media has smaller sized fibers to provide a lower nanoparticle density. Alternatively, this structure can be inverted to provide a greater nanoparticle density in the downstream portion of the filtration media.

[0161] The fibers in the media can be held connected to other fibers by thermal bonding, chemical bonding, or intertangling. Bi-component fibers can be used, particularly in mechanical filtration, and these fibers are formed by extruding two polymers from the same spinneret, both of which are contained in the same filament. Suitable materials for bi-component fibers include, but are not limited to, polypropylene (PP) / polyethylene (PE), polyethylene terephthalate (PET) / polypropylene (PP), and the like.

[0162] In some embodiments, the substrate can include a "high loft" filtration media including spunbond or thermal-bonded carded fibers. As used herein, the term "high loft" refers to a volume of void space that is greater than the volume of total solids. In thermal-bonded carded nonwoven fibers, the loft of the substrate can be controlled in various ways known to those skilled in the art. For example, the loft can be increased by applying less compressive force to the media during the bonding process. In another example, high loft nonwoven materials can be made with fibers having a greater thickness (e.g., greater than 3 denier, such as 5 denier or greater, 6 denier or greater) (discussed in greater detail below). In other embodiments, the loft can be increased by using non-concentric bio-component fibers, such as Figure 5 C, and discussed in greater detail below.

[0163] In certain embodiments, the fibers can include a silicone-based coating to improve the efficiency of the filtration media in capturing contaminants, particularly in the E2 and E3 particle group ranges. The silicone-based coating can include a reactive silicone mini-emulsion. The silicone emulsion can include, for example, a dimethyl silicone emulsion, an amino-type silicone emulsion, an organofunctional silicone emulsion, a resin-type silicone emulsion, a film-forming silicone emulsion, and the like. In one embodiment, the reactive silicone mini-emulsion comprises an amino-functional polydimethylsiloxane and / or a polyethylene glycol monotridecyl ether. Suitable silicone coatings are described in commonly-assigned U.S. Provisional Patent Application No. 63 / 406,686, filed September 14, 2022, the entire disclosure of which is incorporated herein by reference.

[0164] The filtration media can include a charge additive to alter the triboelectric charge of the fibers and increase the stability and / or duration of the triboelectric charge in the filter. This improves the overall filtration efficiency of the filter without compromising other important properties of the filter, such as lifetime, dust holding capacity, and pressure drop or air flow through the filter. Charge additives suitable for triboelectric charging are described in commonly-assigned Provisional Patent Application No. 63 / 410,731, filed September 28, 2022, the entire disclosure of which is incorporated herein by reference for all purposes.

[0165] The fibers can have a thickness suitable for the application. In some embodiments, the fibers have a dimension of about 1 to about 10,000 microns or about 1 to about 1,000 microns or about 10 to 100 microns in at least one dimension. The thickness of the fibers can also be measured in denier, which is a measure of the linear mass density of the fiber. In some embodiments, the linear density of the fibers can be about 1 denier to about 10 denier. Nanoparticles are fibers having a dimension of about 1 to about 1,000 nanometers or about 1 to about 100 nanometers in at least one dimension. The dimension of the above-mentioned fibers and nanoparticles can be a diameter or a width, depending on the shape of the fiber or nanoparticle.

[0166] For gas filters, such as pleated or non-pleated air filters, the linear density of the fibers can be from about 1 denier to about 10 denier. The filter media can include fibers having the same or different linear densities.

[0167] The linear density of the fibers in air filters is typically about 3 denier or less to ensure that the fibers are small enough to capture contaminants passing through the filter. Applicants have unexpectedly discovered that by using nanoparticles dispersed in the filter media, the fibers can have a greater linear density, e.g., greater than 3 denier. This is because the nanoparticles provide significant filtration capability. In some cases, the linear density of the fibers can be greater than 3 denier, 5 denier or greater, 6 denier or greater, or as great as 7-10 denier.

[0168] Applicants have also discovered that in some applications, fibers having a greater linear density than fibers used in conventional filters, e.g., greater than about 3 denier, provide more open space or porosity in the filter media, which allows the nanoparticles to be dispersed therein at a greater density. Although this can be counterintuitive to one skilled in the art, Applicants have discovered that fibers incorporating a greater linear density of nanoparticles actually improve the overall efficiency of the filter.

[0169] In certain embodiments, the filter media can include at least two different fiber thicknesses or linear densities to provide at least two different filtration layers within the same filter media. For example, in some cases, a portion of the filter media will include fibers having a linear density greater than 3 denier, e.g., 5 denier or greater or 6 denier or greater. Another portion of the filter media will include fibers having a more standard linear density of 3 denier or less. This dual layer filter media creates a first filtration portion that primarily utilizes the nanoparticles having a high density within the larger thickness fibers to filter contaminants and a second filtration portion that primarily utilizes the fibers having a lower linear density to filter contaminants, but both portions can include nanoparticles dispersed throughout the fibers. In certain embodiments, the filter media can include three or more separate portions or layers having different denier fiber ranges within each portion.

[0170] Figure 27A dual layer filtration media is shown that includes a first substrate 40 having a first surface 42 and a second surface 44 opposite the first surface; and a second substrate 50 having a first surface 52 and a second surface 54 opposite the first surface. The second surface 44 of the first substrate 40 is bonded to the second surface 54 of the first substrate in any manner known to those skilled in the art. The first substrate 40 includes fibers 46 having a relatively small linear density (e.g., about 3 denier or less). The second substrate 50 includes fibers 56 having a relatively large linear density (e.g., about 3 denier or more, such as 5 denier, 6 denier or more). The second substrate 50 also includes individual nanoparticles 58 dispersed throughout the fibers 56 and bonded to the fibers 56 and / or retained by the second substrate 50. The first substrate 40 can or can not also include nanoparticles.

[0171] The first substrate 40 is configured to filter contaminants primarily with the fibers 46, but as noted previously, the first substrate 40 can also include nanoparticles. The second substrate 50 is configured to filter contaminants with both the fibers 56 and the nanoparticles 58.

[0172] In some embodiments, the substrates can include additives, such as anti-bacterial and / or anti-viral compositions, such as silver, zinc, copper, organosilicone, tributyl tin, organic compounds containing chlorine, bromine, or fluorine compounds.

[0173] The fibers can include bio-component fibers, which include two or more different fibers bonded to one another. The fibers can include the same material or different materials.

[0174] In certain embodiments, the filtration media (i.e., fibers and / or nanoparticles) can be electrostatically charged so that contaminants are captured, for example, with mechanical and electrostatic filtration. The bond between the fibers and nanoparticles can also be enhanced by electrostatically charging the nanoparticles, fibers, or both. For example, in certain embodiments, the fibers are electrostatically charged so that mechanical filtration can be achieved through the nanoparticles, while electrostatic filtration can be achieved through the electret substrate. The electrostatic or electret substrate can be a high loft triboelectric filtration media made by carding and needle punching. In one embodiment, the nanoparticles are deposited into the substrate prior to needle punching, and then the electrostatic fibers and nanoparticles are needle punched together.

[0175] The substrate, nanoparticles, or both can be electrostatically charged using triboelectric methods, corona discharge, electrospinning, hydrodynamic charging, a charging bar, or other known methods. Corona charging is suitable for charging single polymer fibers or fiber blends or fabrics. Tribocharging can be suitable for charging fibers with different electronegativities. Electrospinning combines the charging of the polymer and the spinning of the fiber into a one-step process. Charge additives suitable for triboelectric charging are described in co-assigned provisional patent application number 63 / 410,731, filed September 28, 2022, the entire disclosure of which is hereby incorporated by reference herein for all purposes.

[0176] Nanoparticles with different triboelectric properties relative to the fibers can be selected to enhance particle removal using the triboelectric effect. With this approach, the generated nanoparticles form in an electric field and are less susceptible to contamination with chemicals that can mitigate the triboelectric effect. Nanoparticles with different adsorption properties or surface charge characteristics than the coarse fibers can also be used, such as for oil or water filtration. This difference can be used to enhance or create a local electric field gradient within the filtration media to enhance particle removal. The nanoparticles and coarse fibers can have different wetting characteristics.

[0177] In certain embodiments, the filtration media discussed herein can be part of a filtration device that captures or absorbs contaminants, such as a liquid filter, a gas filter for air filtration for home and commercial use, a surgical mask or other mask, and the like. The filtration device can be a mechanical filter, an adsorptive filter, a barrier filter, an ion exchange filter, a reverse osmosis filter, a surface filter, a depth filter, and the like, and can be designed to remove many different types of contaminants from air, water, and the like.

[0178] In one such embodiment, the filtration media is incorporated into an air filter that removes particles and contaminants from air, such as a HEPA filter (i.e., a pleated mechanical air filter), an HVAC filter, a UV light filter, an electrostatic filter, a washable filter, a media filter, a spun glass filter, a pleated or non-pleated air filter, an activated carbon filter, a pocket filter, a V-bank compact filter, a filter sheet, a flat cell filter, a filter cartridge, and the like. The filtration media can comprise the filtration media for the air filter and can be supported by a support layer, a scrim layer, or can be included in other layers or materials. Applicants have found that incorporating nanoparticles into the filtration media at a depth, as discussed herein, greatly improves the efficiency of the air filter without compromising other factors, such as pressure drop through the filter (i.e., air flow). Moreover, these materials increase the overall dust holding capacity, thereby increasing the life of the filter, particularly as compared to filters that rely on or primarily rely on electrostatic action to improve efficiency.

[0179] Conventional residential and commercial air filters, such as HEPA and HVAC filters, are typically rated according to the ability of the filter to capture particles of about 0.3 to 10 microns. This rating is referred to as the Minimum Efficiency Reporting Value or MERV, and is established by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). MERV ratings range from 1-16, with higher numbers indicating higher efficiency at capturing specific types of particles. Conventional mechanical air filters typically report a MERV rating of about 8 for the fibrous filter material.

[0180] Air filters are typically rated based on their initial efficiency (i.e., the efficiency of the air filter before use) as well as their efficiency over time and use. The latter efficiency is typically tested by a conditioning step, see ASHRAE Standard 52.2 Appendix J.

[0181] The air filters provided herein have an initial MERV rating of greater than about 10 and a pressure drop of less than about 0.5 inches of water. In some cases, the initial MERV rating is about 11, the pressure drop is equal to or less than about 0.17 inches of water, or the initial MERV rating is about 13, the pressure drop is equal to or less than about 0.36 inches of water, or the initial MERV rating is about 14, the pressure drop is equal to or less than about 0.5 inches of water.

[0182] The gas filters provided herein have a MERV rating of 10 or higher after conditioning according to ASHRAE Standard 52.2 Appendix J. In some embodiments, the MERV rating is 13 or higher after conditioning the gas filter using ASHRAE Standard 52.2, ISO Standard 16890, or any other acceptable standard in the industry.

[0183] The MERV rating of the fibrous filter media discussed herein will vary depending on a number of factors, including the type and size of the fibers used in the filter media, the density of the individual nanoparticles in the filter media, the width of the filter media, the number and size of pleats, if any, and the like. The MERV rating can be measured for both fibrous product sheets as well as for fibrous products formed into pleated filter media, and the pressure drop can be different for each product. Likewise, the pressure drop across the filter media depends on a number of factors, including those mentioned above.

[0184] One factor that affects the MERV rating and the pressure drop is the density or loading of the nanoparticles within the substrate relative to the density of the fibers within the substrate. Applicants have found that the lower the ratio between the substrate density and the nanoparticle density, the higher the MERV rating and the higher the pressure drop of the filter. In certain embodiments, the filter media described herein has a nanoparticle areal density of about 0.1 g / m2to about 20 g / m2, preferably at least about 2 g / m2.

[0185] In some cases, the density of the nanoparticles will also depend on the density of the actual filter media (i.e., the density of the coarse fibers). As discussed in more detail below with reference to Table 2 below, a density ratio (substrate gsm divided by added nanoparticle gsm) of about 67 results in a pressure drop of about 0.14 inches of water and an initial MERV rating of 10. A density ratio of about 33.4 increases the MERV rating to 10, while only resulting in an increase in pressure drop to about 0.17. A density ratio of about 22.3 increases the initial MERV rating to about 12, while the pressure drop is about 0.24 inches of water.

[0186] Thus, the efficiency or MERV rating of the filter can be increased with increasing amounts of added nanoparticles. In particular, Applicants have found that, for example, an amount of added nanoparticles of at least 2 g / m 2 yields a filter having a MERV rating of about 10. An amount of 4 or 6 g / m 2 added nanoparticles provides filters having MERV ratings of about 12 and 13, respectively. An amount of 10 g / m 2 or more added nanoparticles results in filters having MERV ratings of 15 or more.

[0187] Applicants have also found that including fibers having a greater thickness or linear density results in larger pore diameters, and thus larger pore volumes, thereby allowing for a higher density of nanoparticles within the substrate. This results in higher MERV ratings and pressure drops (as discussed below with reference to Table 2). For example, Applicants were able to make an air filter having a MERV rating of 14 and a pressure drop of 0.5 inches of water using 5 denier bio-component fibers. Similarly, Applicants were able to make a filter having a MERV rating of 13 and a pressure drop of only about 0.29 inches of water using 5 denier bio-component fibers.

[0188] The fibrous products disclosed herein can be used in medical face masks or other medical applications, such as filter cartridges in respirators. Medical face masks are designed to protect medical personnel and / or patients from microorganisms and other substances. For example, medical face masks can block bacteria (e.g., which can be about 3 microns in size) as well as viruses (e.g., which can be about 0.1 micron in size). Face masks are made using multiple layers of filtration media and have ear loops, ties, or other structures for attaching the face mask to a person's face. A wire can be incorporated into at least the upper portion of the face mask so that at least that portion conforms to a person's face. The face mask can include a rigid polymer structure designed to hold the multiple layers of filtration media in front of a person's face. In one example, the face mask has three layers. The outer and inner layers contain filtration media (e.g., spunbond polypropylene) that provides air permeability, but any of the materials mentioned herein can also be used. The middle layer is disposed between the inner and outer layers and contains a microfiber substrate with nanoparticles deposited to a depth in the substrate to provide an initial MERV of greater than 8, preferably a MERV of greater than 10, and more preferably a MERV of 13 or greater. The pressure drop through the face mask is 3 to 6 mm of water, and more preferably 4 mm of water for air permeability. The efficiency of the face mask is desirably about 95%. Other examples of face masks have four or more layers. The multiple layers of fibrous products can be combined into a single face mask.

[0189] In certain embodiments, the filtration media can be included in a film or layer having holes, pores, or perforations. The holes can be imprinted into a pattern (e.g., circular, diamond, hexagonal, oblong, triangular, rectangular, etc.) and then stretched until the holes are formed in the thinned areas created by the imprinting. Such apertured substrates can be formed from a variety of polymers (e.g., polypropylene, polyethylene, high density polyethylene ("HDPE"), etc.). The polymeric layer can include, for example, an extruded film. Apertured films are commercially available and sold under the trademark Delnet®. The substrate is provided in the form of a roll stock and the nanoparticles are deposited into the substrate in a roll-to-roll process.

[0190] In other embodiments, a gas filter includes a filtration media and a substantially rigid support layer adhered to the filtration media. The support layer contains fibers and individual nanoparticles dispersed in the layer to a depth. The nanoparticles are configured to filter contaminants passing through the support layer.

[0191] Figure 28A filtration product 700 is shown that includes a filtration media 710 that includes fibers 722 and nanoparticles 720 dispersed in at least a portion of the filtration media 710. As shown, the filtration media 710 has a first upper surface 712 and a second lower surface 714. The nanoparticles have been dispersed through the upper surface 712 such that they extend past the upper surface 712 and into a depth of the filtration media 710, as discussed above. The filtration product 700 also includes a support layer 730, which can be any suitable support layer known in the art, such as a substantially rigid polymer that provides support for the filtration media 710, or an open- pore membrane having a plurality of pores for passage of gas or fluid therethrough, as discussed above.

[0192] Figure 29 Another filtration product 740 is shown that includes a filtration media 710 that includes fibers 722 and nanoparticles 720 dispersed in a portion of the filtration media 710. In this embodiment, the product 740 includes a scrim layer 750 that is adhered to the support layer 730.

[0193] Figure 30 A dual layer filtration product 760 is shown that includes a first filtration media 762 and a second filtration media 764 adhered to one another. As shown, the nanoparticles 720 have been dispersed in a depth of each filtration media 762, 764. In this embodiment, the nanoparticles 720 have been dispersed through the inner surfaces 766, 768 of the filtration media 762, 764. In another embodiment (not shown), the nanoparticles are dispersed through the outer surfaces 770, 772 of the filtration media 762, 764. In yet another embodiment, the nanoparticles 720 can be deposited on the inner surface 766 of the media 762 and the outer surface 772 of the media 764.

[0194] Example 1 A microfiber substrate of bicomponent fibers having an inner circular portion of polyester and an outer concentric portion of HDPE was provided in the form of a roll. In a roll-to-roll process, the substrate was sprayed with adhesive and nanoparticles or nanoparticles of bioresorbable glass fibers were deposited. The nonwoven product was then heated in an oven and the cooled nonwoven product was collected onto another roll.

[0195] Nanoparticles were deposited according to the procedure described in the following Figures 12-16 In the experiment, bioresorbable glass nanoparticles were used. The nanofibers had a diameter of about 700 nm and a length of about 500 microns. In the following examples, a carded through-air bonded nonwoven made from bicomponent fibers was used as the substrate: Flat sheet filter media samples were tested at a filtration velocity of 110 fpm. The sample size was 12" x 12". NaCI salt particles ranging from 0.3 to 10 microns were used as the contaminant.

[0196] Example 2 Carded nonwoven made from 3 denier PET / PE bicomponent fibers were used as the substrate. A composition comprising water, 2-hexyloxyethanol, isopropyl alcohol amine, sodium dodecylbenzenesulfonate, laurylamine oxide, ammonium hydroxide was used as the binder. Different nanofiber loading was controlled by adjusting the line speed.

[0197] Table 1 This example demonstrates that by controlling the amount of nanofiber loading, the MERV rating was improved from MERV 7 to MERV 13.

[0198] Example 3 High loft air-through bonded carded nonwoven with 5 denier bicomponent fibers were used as the substrate. A typical starch binder was diluted and sprayed on prior to nanofiber deposition. As the solvent evaporated and dried under IR heater, the starch fully bound the nanoparticles.

[0199] Table 2 Example 4 Spunbond or meltblown media were used as the substrate, with nanoparticles incorporated into the substrate after IPA discharge, as described herein. The spunbond fibers were made from a molten polymer that was spun and drawn to create filaments. The average basis weight of the substrate was about 90 gsm, and the average thickness was about 0.57 mm. A base sample was used that did not have any nanoparticles incorporated. Four separate samples were prepared that included nanoparticles incorporated into the substrate, as described herein. In sample 2, the nanoparticles were incorporated into the meltblown fibers after IPA discharge. In samples 1, 3, and 4, the nanoparticles were incorporated into the spunbond fibers after IPA discharge. The results of this test are shown in Table 3 below.

[0200] Table 3 As shown, the efficiency of the filtration media samples incorporating nanoparticles was higher than the base sample in all three particle groups, and the efficiency of the E2 and E3 particle groups was significantly improved. Using the nanoparticles, the overall MERV rating of the samples was improved from MERV 7 (base sample) to MERV 12 to MERV 16. The pressure drop of the base sample, which contained no nanoparticles, was 0.07 inches of water. The pressure drop of samples 1-4 increased slightly, from 0.17 to 0.41 inches of water. In sample 2, in which the nanoparticles were incorporated into the meltblown fibers, the MERV rating was 14 and the pressure drop was 0.24 inches of water.

[0201] Example 5 A 5 denier thermal bonded carded fiber was used as the substrate. A base sample that did not incorporate nanoparticles was used. Two separate samples were prepared that included nanoparticles incorporated into the substrate, as described herein. The results of this test are shown in Table 4 below.

[0202] Table 4 As shown, the efficiency of the filtration media samples incorporating nanoparticles was higher than the base sample in all three particle groups, and the efficiency of the E2 and E3 particle groups was significantly improved. Using the nanoparticles, the overall MERV rating of the samples was improved from MERV 7 (base sample) to MERV 12 to MERV 16. The pressure drop of the base sample, which contained no nanoparticles, was 0.07 inches of water. The pressure drop of samples 1-4 increased slightly, from 0.17 to 0.41 inches of water. In sample 2, in which the nanoparticles were incorporated into the meltblown fibers, the MERV rating was 14 and the pressure drop was 0.24 inches of water.

[0203] Example 6 Meltblown fibers were used as the substrate. The average basis weight of the substrate was about 24 gsm and the average thickness was about 0.4 mm. A base sample that did not incorporate nanoparticles or adhesive (e.g., PVOH) was used. Sample 1 included meltblown fibers with the side facing up. PVOH was sprayed on the fibers, but no nanoparticles were incorporated therein. Sample 2 included meltblown fibers with the fleece side facing up. PVOH was sprayed on the fibers, but no nanoparticles were incorporated therein. Sample 3 included meltblown fibers on which PVOH was sprayed, and nanoparticles were incorporated into the fibers, as described herein. The results of this test are shown in Table 5 below.

[0204] Table 5 As shown, the efficiency of Sample 3, which incorporated nanoparticles, increased over the other three base samples in all three particle groups, particularly in the E1 particle group. The overall MERV rating of Sample 3 increased from MERV 13 or 14 (base samples) to MERV 15 (with nanoparticles). The PVOH added to Samples 2 and 3 did not significantly increase the pressure drop (i.e., 0.35 for the base samples, 0.38 and 0.41 for Samples 1 and 2). The pressure drop of Sample 3 did increase from about 0.40 inches of water to about 1 inch of water. In Sample 3, which incorporated nanoparticles into the meltblown fibers, the MERV rating was 15 and the pressure drop was 1.02 inches of water.

[0205] Example 7 Five denier thermal bonded carded fibers were used as the substrate. A base sample was used that did not incorporate nanoparticles. Seven additional samples were prepared that included the five denier carded fibers with nanoparticles incorporated into the substrate, as described herein. The results of this test are shown in Table 6 below.

[0206] Table 6 As shown, the efficiency of the seven samples that incorporated nanoparticles was higher than the base sample in all three particle groups, particularly in the E2 and E3 particle groups. The overall MERV rating increased from MERV 6 (base sample) to MERV 7 to MERV 13 (with nanoparticles). The pressure drop increased only from 0.03 inches of water to a maximum of 0.32 inches of water.

[0207] Example 8 High loft spunbond fibers were used as the substrate in a continuous fiber production line. This trial included two different versions: 205-6 and 205-2, in which the settings on the continuous fiber production line were changed to produce two substrates of different weight and thickness. A base sample was used for each version (205-6 and 205-2) that did not incorporate nanoparticles. Six additional samples were prepared that included the 205-6 and 205-2 fibers with nanoparticles incorporated into the substrate, as described herein. The results of this test are shown in Table 7 below.

[0208] Table 7 As shown, the efficiency of the six samples that incorporated nanoparticles was significantly higher than the base sample in all three particle groups. The overall MERV rating increased from MERV 6 (base sample) to MERV 11 to MERV 14 (with nanoparticles). The pressure drop increased only from 0.04 inches of water to a maximum of 0.87 inches of water. The pressure drop increased only to a maximum of 0.48 inches of water in the 205-2 samples.

[0209] Example 9 Spunbond and meltblown fibers were used as the substrate. For the spunbond fibers, the average basis weight of the substrate was about 70 gsm, while for the meltblown fibers, the average basis weight of the substrate was about 24 gsm. The average thickness of the substrate was about 0.75 mm. A base sample was used that did not incorporate nanoparticles. Five additional samples were prepared that included spunbond and meltblown fibers and nanoparticles incorporated into the fibers, as described herein. In samples 1-3, the nanoparticles were sprayed onto the meltblown fibers. In samples 4 and 5, the nanoparticles were sprayed onto the spunbond fibers. Additionally, in samples 1 and 2, no adhesive PVOH was sprayed onto the substrate. PVOH was sprayed onto samples 3-5. The results of this test are shown in Table 8 below.

[0210] Table 8 As shown, in all three particle groups, the efficiency of the five samples incorporating nanoparticles was significantly improved over the base sample. The overall MERV rating was improved from MERV 5 (base sample) to MERV 16 (using nanoparticles). The pressure drop increased only up to a maximum of 0.56 inches of water. In samples 3-5 (PVOH sprayed onto the substrate), the pressure drop increased only up to a maximum of 0.4 inches of water.

[0211] Example 10 5 denier through-air bonded carded glass fibers were used as the substrate. A base sample was used that did not incorporate nanoparticles. Three additional samples were prepared that included 5 denier carded glass fibers and nanoparticles incorporated therein. The results of this test are shown in Table 9 below.

[0212] Table 9 As shown, in all three particle groups, the efficiency of the three samples incorporating nanoparticles was significantly improved over the base sample. The overall MERV rating was improved from MERV 6 (base sample) to MERV 12 or MERV 13 (using nanoparticles). The pressure drop increased only up to a maximum of 0.27 inches of water.

[0213] Example 11 A blend of 5 denier and 7 denier through-air bonded carded glass fibers was used as the substrate. The media was through-air bonded. A base sample was used that did not incorporate nanoparticles. Nineteen additional samples were prepared that included a blend of 5 denier and 7 denier carded glass fibers and nanoparticles incorporated therein. The results of this test are shown in Table 10 below.

[0214] Table 10 As shown, in all three particle groups, the efficiency of all 19 nanoparticle- incorporated samples was significantly improved over the base sample. The overall MERV rating was improved from MERV 6 (base sample) to MERV 10 to MERV 13 (with nanoparticles) (the rating of most samples was MERV 13). The pressure drop increased from only 0.03 inches of water to a maximum of 0.31 inches of water.

[0215] While the apparatus, systems and methods have been described in detail according to certain preferred embodiments thereof, many modifications, alterations, and variations can be implemented within the spirit and scope of the disclosure as will be appreciated by those skilled in the art. Accordingly, the foregoing description is to be interpreted only as illustrative of the general inventive concept embodied within the present disclosure, and is not intended to limit the generic inventive concept defined by the appended claims.

[0216] For example, in a first aspect, a first embodiment includes a system for manufacturing a filtration medium. The system includes: a container for receiving a cluster of nanoparticles; one or more vibration elements coupled to the container and configured to pulse the cluster of nanoparticles to transport the cluster of nanoparticles through the container; and a device coupled to the container for receiving the nanoparticles, the device including one or more components for combining the nanoparticles with fibers to form the filtration medium.

[0217] A second embodiment is the first embodiment, wherein the one or more vibration elements are disposed on an outer wall of the container.

[0218] A third embodiment is any combination of the preceding two embodiments, wherein the one or more vibration elements are configured to vibrate the outer wall of the container to separate the nanoparticles from the outer wall of the collector vessel.

[0219] A fourth embodiment is any combination of the preceding three embodiments, wherein the one or more vibration elements are disposed on an interior of the container.

[0220] A fifth embodiment is any combination of the preceding four embodiments, further comprising a power source coupled to the vibration elements.

[0221] A sixth embodiment is any combination of the preceding five embodiments, wherein the power source comprises an electric motor.

[0222] A seventh embodiment is any combination of the preceding six embodiments, wherein the vibration elements are coupled to a source of compressed air.

[0223] An eighth embodiment is any combination of the preceding seven embodiments, further comprising a bulk bin for receiving the cluster of nanoparticles and a collector vessel coupled to the bulk bin, wherein the vibration elements are disposed on the collector vessel.

[0224] The ninth embodiment is any combination of the previous eight embodiments, wherein the collection vessel has an upper opening coupled to the bulk bin, and a lower opening, wherein the lower opening has a larger cross-sectional area than the upper opening.

[0225] The tenth embodiment is any combination of the previous nine embodiments, further comprising a second set of one or more vibration elements on the bulk bin.

[0226] The eleventh embodiment is any combination of the previous ten embodiments, wherein the bulk bin comprises one or more rotors disposed inside the bulk bin for transporting the clusters of nanoparticles through the bulk bin.

[0227] The twelfth embodiment is any combination of the previous eleven embodiments, further comprising an elevator coupled to the collection vessel for elevating the clusters of nanoparticles from a first height of the vessel to a second height greater than the first height.

[0228] The thirteenth embodiment is any combination of the previous twelve embodiments, further comprising a feeder for advancing the substrate comprising fibers from an upstream end to a downstream end.

[0229] The fourteenth embodiment is any combination of the previous thirteen embodiments, further comprising a dispersion system disposed between the elevator and the feeder, wherein the dispersion system comprises a nozzle for dispersing the nanoparticles onto a first surface of the substrate comprising fibers such that the nanoparticles at least penetrate through the first surface of the substrate.

[0230] The fifteenth embodiment is any combination of the previous fourteen embodiments, further comprising a fiberization device configured to separate individual nanoparticles from the clusters of nanofibers.

[0231] The sixteenth embodiment is any combination of the previous fifteen embodiments, further comprising a coating device for dispersing a binder onto the fibers in the substrate.

[0232] The seventeenth embodiment is any combination of the previous sixteen embodiments, further comprising a dryer disposed between the housing and the downstream end of the feeder proximate the feeder for heating the nanoparticles and fibers.

[0233] The eighteenth embodiment is any combination of the previous seventeen embodiments, wherein the individual nanoparticles are spaced apart from each other and have a size in at least one dimension that is less than 1 micron.

[0234] In another aspect, there is provided a filtration medium manufactured from any combination of the previous eighteen embodiments.

[0235] In another aspect, there is provided a filter manufactured from any combination of the previous eighteen embodiments.

[0236] In another aspect, the first embodiment includes a feed system for delivering nanoparticles. The system includes: a vessel for receiving clusters of nanoparticles, one or more components for converting each cluster of nanoparticles into a set of nanoparticles having a mass or volume less than the cluster of nanoparticles, a conveyor for advancing the set of nanoparticles, and one or more vibration elements for pulsing the nanoparticles.

[0237] The second embodiment is the first embodiment, wherein the feed system is configured to deliver the set of nanoparticles at a controlled volumetric flow rate.

[0238] The third embodiment is any combination of the previous two embodiments, wherein the vessel includes a bulk bin including one or more rotors within the bulk bin, wherein each rotor includes one or more rotating blades for mechanically separating each cluster of nanoparticles into the set of nanoparticles.

[0239] The fourth embodiment is any combination of the previous three embodiments, wherein the rotor delivers the set of nanoparticles through the bulk bin.

[0240] The fifth embodiment is any combination of the previous four embodiments, wherein the rotor is configured to rotate about an axis transverse to a height of the vessel.

[0241] The sixth embodiment is any combination of the previous five embodiments, wherein at least some of the rotors rotate in a clockwise direction and at least some of the rotors rotate in a counterclockwise direction.

[0242] The seventh embodiment is any combination of the previous six embodiments, further comprising a collection vessel coupled to the bulk bin, wherein the one or more vibration elements are disposed on an outer wall of the collection vessel.

[0243] The eighth embodiment is any combination of the previous seven embodiments, wherein the collection vessel has an upper opening coupled to the bulk bin, and a lower opening, wherein the lower opening has a larger cross-sectional area than the upper opening.

[0244] The ninth embodiment is any combination of the previous eight embodiments, further comprising a power source coupled to the vibration elements.

[0245] The tenth embodiment is any combination of the previous nine embodiments, wherein the power source includes an electric motor.

[0246] The eleventh embodiment is any combination of the previous ten embodiments, wherein the vibration elements are coupled to a source of compressed air.

[0247] The twelfth embodiment is any combination of the previous eleven embodiments, wherein the conveyor includes an elevator for delivering the cluster of nanoparticles from a first height of the collection vessel to a second height greater than the first height.

[0248] The 13th embodiment is any combination of the preceding 12 embodiments, wherein the elevator comprises a tube having a plurality of discs configured to move through the tube, wherein each disc has an outer diameter that is less than an inner diameter of the tube.

[0249] The 14th embodiment is any combination of the preceding 13 embodiments, wherein the discs define compartments between the discs for containing and transporting nanoparticles.

[0250] The 15th embodiment is any combination of the preceding 14 embodiments, wherein the discs are movable within the tube between a first height and a second height.

[0251] The 16th embodiment is any combination of the preceding 15 embodiments, wherein the feed system further comprises a feed bin coupled to the elevator at the second height.

[0252] The 17th embodiment is any combination of the preceding 16 embodiments, wherein the feed bin comprises one or more rotating elements for transporting the group of nanoparticles through the feed bin to the dispersion device.

[0253] The 18th embodiment is any combination of the preceding 17 embodiments, wherein the feed bin comprises an auger comprising one or more curved vanes for redirecting the group of nanoparticles.

[0254] The 19th embodiment is any combination of the preceding 18 embodiments, wherein the feed bin comprises one or more vibrating elements for transporting the group of nanoparticles through the feed bin to the dispersion device.

[0255] In another aspect, a filter medium is provided, formed from any combination of the preceding 19 embodiments.

[0256] In another aspect, a gas or liquid filter is provided, formed from any combination of the preceding 19 embodiments.

[0257] In another aspect, the first embodiment is a filter medium formed from a method comprising: delivering a group of nanoparticles into a container; vibrating the container to transport the group of nanoparticles through the container; and combining the nanoparticles with fibers to form the filter medium.

[0258] The 2nd embodiment is the 1st embodiment, further comprising vibrating an outer wall of the container to separate the group of nanoparticles from the outer wall.

[0259] The 3rd embodiment is any combination of the preceding 2 embodiments, further comprising delivering the group of nanoparticles into a bulk bin, and transporting the group of nanoparticles through the bulk bin with one or more rotors.

[0260] The fourth embodiment is any combination of the preceding three embodiments, further comprising elevating the cluster of nanoparticles from a first height of the vessel to a second height greater than the first height.

[0261] The fifth embodiment is any combination of the preceding four embodiments, further comprising: advancing the substrate comprising fibers from an upstream end to a downstream end; and dispersing the nanoparticles onto the first surface of the substrate comprising fibers such that the nanoparticles at least penetrate through the first surface of the substrate.

Claims

1. A system for manufacturing filter media, the system comprising: A container used to receive clusters of nanoparticles; One or more vibrating elements are coupled to the container and configured to pulse the nanoparticle clusters to convey the nanoparticle clusters through the container; as well as A device coupled to the container for receiving nanoparticles, the device including one or more components for combining the nanoparticles with fibers to form the filter medium.

2. The system of claim 1, wherein the one or more vibrating elements are disposed on the outer wall of the container.

3. The system of claim 2, wherein the one or more vibrating elements are configured to vibrate the outer wall of the container to separate the nanoparticles from the outer wall of the container.

4. The system of claim 1, wherein the one or more vibrating elements are disposed inside the container.

5. The system of claim 1 further includes a power source coupled to the vibrating element.

6. The system of claim 5, wherein the power source comprises an electric motor.

7. The system of claim 1, wherein the vibrating element is coupled to a compressed air source.

8. The system of claim 1, further comprising a bulk bin for receiving the nanoparticle clusters and a collector coupled to the bulk bin, wherein the vibrating element is disposed on the collector.

9. The system of claim 8, wherein the collecting vessel has an upper opening and a lower opening coupled to the bulk hopper, wherein the lower opening has a larger cross-sectional area than the upper opening.

10. The system of claim 8, further comprising a second set of one or more vibrating elements on the bulk silo.

11. The system of claim 8, wherein the bulk hopper includes one or more rotors disposed inside the bulk hopper for conveying the nanoparticle clusters through the bulk hopper.

12. The system of claim 8, further comprising a lifter coupled to the collecting vessel for lifting the nanoparticle cluster from a first height of the vessel to a second height greater than the first height.

13. The system of claim 1, further comprising a feeder for advancing the fiber-containing substrate from the upstream end to the downstream end.

14. The system of claim 13, further comprising a dispersing system disposed between the elevator and the feeder, wherein, The dispersion system includes a nozzle for dispersing the nanoparticles onto a first surface of a fiber-containing substrate, such that the nanoparticles penetrate at least through the first surface of the substrate.

15. The system of claim 1, further comprising a fiberization device configured to separate individual nanoparticles from the nanofiber cluster.

16. The system of claim 1, further comprising a coating device for dispersing an adhesive onto fibers in the substrate.

17. The system of claim 16, further comprising a dryer disposed near the feeder between the housing and the downstream end of the feeder for heating the nanoparticles and the fibers.

18. The system of claim 15, wherein the individual nanoparticles are spaced apart from each other and at least one dimension has a size of less than 1 micrometer.

19. A filter medium formed by the system of claim 1.

20. A filter formed by the system of claim 1.

21. A feeding system for conveying nanoparticles, the system comprising: A container used to receive clusters of nanoparticles; One or more components are used to convert each nanoparticle cluster into a nanoparticle group, the nanoparticle group having a smaller mass or volume than the nanoparticle cluster; A conveyor for propelling the nanoparticle assembly; and One or more vibrating elements are used to pulse the nanoparticles.

22. The system of claim 21, wherein the feeding system is configured to deliver the nanoparticle assembly at a controlled volumetric flow rate.

23. The system of claim 21, wherein the container includes a bulk bin, the bulk bin including one or more rotors within the bulk bin, wherein each rotor includes one or more rotating blades for mechanically separating each nanoparticle cluster into the nanoparticle group.

24. The system of claim 23, wherein the rotor conveys the nanoparticle assembly through the bulk hopper.

25. The system of claim 23, wherein the rotor is configured to rotate about an axis tangential to the height of the container.

26. The system of claim 23, wherein at least some rotors rotate clockwise and at least some rotors rotate counterclockwise.

27. The system of claim 21, further comprising a collector coupled to the bulk silo, wherein one or more vibrating elements are disposed on the outer wall of the collector.

28. The system of claim 27, wherein the collecting vessel has an upper opening and a lower opening coupled to the bulk hopper, wherein the lower opening has a larger cross-sectional area than the upper opening.

29. The system of claim 21 further includes a power source coupled to the vibrating element.

30. The system of claim 27, wherein the power source comprises an electric motor.

31. The system of claim 21, wherein the vibrating element is coupled to a compressed air source.

32. The system of claim 21, wherein the conveyor includes a lifter for conveying the nanoparticle cluster from a first height of the collecting dish to a second height greater than the first height.

33. The system of claim 32, wherein the lifter comprises a tube having a plurality of discs configured to move through the tube, wherein each disc has an outer diameter smaller than the inner diameter of the tube.

34. The system of claim 33, wherein the disks define compartments between the disks for containing and transporting the nanoparticles.

35. The system of claim 34, wherein the disk is movable within the tube between the first height and the second height.

36. The system of claim 32, wherein the feeding system further comprises a feeding bin coupled to the elevator at the second height.

37. The system of claim 36, wherein the feed hopper includes one or more rotating elements for conveying the nanoparticle assembly through the feed hopper to a dispersion device.

38. The system of claim 36, wherein the feed hopper includes a screw conveyor, the screw conveyor including one or more curved blades for reorienting the nanoparticle assembly.

39. The system of claim 36, wherein the feed hopper includes one or more vibrating elements for conveying the nanoparticle clusters through the feed hopper to a dispersion device.

40. A filter medium formed by the system of claim 21.

41. A filter formed by the system of claim 21.

42. A filter medium formed by a method comprising the following steps: Delivering nanoparticle clusters into containers; Vibrate the container to transport the nanoparticle clusters through the container; and The nanoparticles are combined with fibers to form a filter medium.

43. The filter medium of claim 42, further comprising vibrating the outer wall of the container to separate the nanoparticle clusters from the outer wall.

44. The filter medium of claim 42, further comprising delivering the nanoparticle clusters into a bulk hopper, and conveying the nanoparticle clusters through the bulk hopper using one or more rotors.

45. The filter medium of claim 42, further comprising raising the nanoparticle cluster from a first height of the container to a second height greater than the first height.

46. ​​The filter medium of claim 45, further comprising: The fiber-containing substrate is advanced from the upstream end to the downstream end; And disperse the nanoparticles onto a first surface of a fiber-containing substrate such that the nanoparticles at least penetrate through the first surface of the substrate.

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