Patent Application
20240278172
The subject invention is directed to air filtration media, and more particularly, to air filters for HVAC applications, window screens, indoor barrier screens or partitions, and modular furniture that use an electro-spun polymeric nanofiber membrane media with high filtering efficiency and excellent porosity for air filtration, and which optionally include antimicrobial compounds incorporated therewith.
Gaseous flows (e.g. air flows) often carry undesirable entrained particulates. Filters are commonly employed to remove some or all of the particulates from the gaseous flows. Filter media including nanofibers formed using an electrostatic spinning process is also known as disclosed for example, in U.S. Pat. No. 8,172,092, the disclosure of which is incorporated herein by reference. Nanoparticle compositions used for making antimicrobial or antiviral agents to treat fibrous materials are also known, as disclosed for example in U.S. Pat. No. 9,434,006, the disclosure of which is incorporated herein by reference.
Applicant recognizes that it would be beneficial to provide electrospun polymer nanofibrous membranes that provide high filtering efficiency and excellent porosity, optionally wherein the membrane is treated with one or more antimicrobial or antiviral agents. Such a membrane can be particularly useful in blocking and inactivating pathogens, including viruses such as COVID-19.
The subject electrospun polymeric nanofiber membranes are suitable for use in indoor air filtration applications, such as in heating, ventilation and air conditioning (HVAC) systems, as well as window screens, furniture such as room dividers, movable or stationary indoor barrier screens, and modular furniture panels, such as cubicle panels.
In accordance with one aspect of the invention, an air filtration membrane is provided, which includes a substrate and a network of electrospun polymeric nanofibers deposited on the substrate, wherein the network has a total polymer weight of 5 to 25% and wherein said air filtration membrane has a minimum air filtration efficiency of between MERV 13 and HEPA filtration.
The polymeric nanofibers can include polyacrylonitrile, polyvinylidene fluoride, thermoplastic polyurethane or polypropylene. The polymeric nanofibers can have an average diameter of 50 to 500 nm. The polymeric nanofibers can create a layer of thickness between 0 to 150 microns. The substrate material can include non-woven polyester fibrous or microfibrous material, or non-woven polypropylene fibrous material.
The substrate material can include a polyester screen with mesh openings ranging from 50 to 1000 microns. The substrate material can include a vinyl coated polyester screen. The substrate material can include a vinyl coated fiberglass screen.
Either the polymeric nanofibers or substrate can be coated with an antifungal, antibacterial, and/or antiviral agent. Either the polymeric nanofibers or substrate can be treated with non-spherical, spherical or coral shaped metal nanoparticles, on the surface thereof.
The air filtration membrane can have a visible light transmittance range from 0 to 60%. The air filtration membrane can have a minimum Frazier air permeability of about 10 L/m2/s at 125 Pa.
The air filtration membrane can have a protective layer that is thermally laminated or bonded to the membrane for structural support. The membrane can be pleated to maximize filtration surface area.
The network of polymeric nanofibers can include multiple polymer types, which include multiple layers of different nanofibers, or multiple polymers co-spun together to form a blended layer.
The air filtration membrane can be incorporated into a filter for use in HVAC systems. The air filtration membrane can be incorporated into a window screen. The air filtration membrane can be incorporated into indoor barrier screens.
The air filtration membrane can be incorporated into indoor modular furniture panels.
The membrane can be configured as a replaceable filter cartridge adapted to slide vertically or horizontally into the modular furniture panel frame and locked into place therein.
The membrane can include one or both sides of a lightweight, permeable fabric sleeve configured to cover a modular furniture panel frame.
The modular furniture panels can be adapted and configured to be attached together by way of brackets or clamps. The brackets or clamps can be magnetized for ease of assembly. The air filtration membrane can have high air permeability.
In accordance with another aspect of the invention, a modular furniture panel, is provided, which includes a structural frame, and an air filtration membrane operatively associated with the frame, wherein the membrane includes a substrate and a network of electro-spun polymeric nanofibers deposited on the substrate.
The network can have a total polymer weight of 5 to 25% and the membrane can have a minimum air filtration efficiency of between MERV 8 and MERV 16. The membrane can be configured as a filter cartridge adapted for insertion into the frame of the modular furniture panel. The membrane can be configured as an air permeable sleeve adapted to enclose the frame of the modular furniture panel. The frame can include means for connecting plural modular furniture panels together to construct an assembly of furniture panels.
So that those skilled in the art will readily understand how to make and use the air filtration devices of the subject invention without undue experimentation, preferred embodiments thereof will be described in detail hereinbelow with reference to the figures wherein:
With reference to
The nano-dimension of the nanofibers 120 gives the subject membranes 100, 200 a high surface area to volume ratio, making it very attractive in applications where high surface area and flow are desirable. Moreover, there is a relatively low pressure drop across the filtration membranes 100, 200, which saves energy when used in connection with mechanical ventilation systems.
The air filtration membranes 100, 200 of the subject invention preferably have a minimum air filtration efficiency of MERV 13, and can have air filtration efficiencies as high as MERV 16 and beyond, to HEPA quality filtration, depending on the implementation. In related terms, the subject air filtration membranes can filter particulate matter ranging from PM10 to PM1.0.
The polymeric nanofibers of the filtration membrane can comprise polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), thermoplastic polyurethane (TPU), polypropylene (PP), or a similar thermoplastic material. Preferably, the polymeric nanofibers in the filtration membrane have an average diameter of 50-500 nm and the membrane has a layer of thickness between 0-150 microns. If desired, the network of polymeric nanofibers can be composed of multiple polymer types (either multiple layers of different nanofibers, or multiple polymers co-spun together to form a blended layer).
For certain implementations, including HVAC applications, the substrate material can comprise non-woven polyester fibrous or microfibrous material, or non-woven polypropylene fibrous material. In other air filtration applications, the substrate material can comprise a polyester screen with mesh opening ranging from 50 to 1000 microns. More particularly, the substrate material can comprise a vinyl coated polyester screen or a vinyl coated fiberglass screen.
The polymeric nanofibers and/or the substrate can be coated with one or more antifungal, antibacterial, and/or antiviral agents. In a preferred aspect, the polymeric nanofibers and/or the substrate are sprayed or otherwise treated with non-spherical, spherical or coral shaped activated metal nanoparticles 230. As a result, such membranes can quickly block droplets carrying a range of viruses including COVID-19, and quickly inactivate pathogens through interaction with the aforementioned metal nanoparticles.
In accordance with the invention, the subject air filtration membranes preferably have a visible light transmittance range of 0-60% and a minimum Frazier air permeability of 10 L/m2/s at 125 Pa. Depending on the precise embodiment, a protective layer is preferably thermally laminated or otherwise bonded to the nanofiber membrane to provide additional structural support or protection.
With reference to
In accordance with a further aspect of the invention, the subject membranes can be incorporated into window screens 420 as shown in
In accordance with still a further aspect of the invention, the subject membranes can be incorporated into indoor barrier screens 430, 440, 700 as shown in
Referring now to
In accordance with this aspect, the panels can be used as barrier walls or room dividers, or several panels of various sizes and/or shapes can be assembled together to construct modular office furniture or cubicles 800, as shown for example in
With reference to
As illustrated, the panels 801, 803, 805 are preferably constructed with a structural frame 810 that is made from a breathable material, i.e., a material formed with holes or openings so that air can flow through, such as mesh, fabric, metal or wood. Alternatively, solid frame materials can be used while still gaining many benefits of the subject nanofiber filtration membranes. In the embodiment of
With reference to
Depending on the implementation, the opening 929 can be in the top edge (illustrated), or alternatively, bottom edge or either side edge of the panel 921, so the cartridge 922 can be inserted into the panel 921 either vertically or horizontally.
As shown in
With reference to
In one application, the panel body 1021 and/or frame are uniquely fabricated for this purpose. In alternative applications, the body 1021, just frame, or both are reclaimed from an existing piece of modular office furniture and retrofit by covering with the filtration membrane sleeve 1022 or inserting a filter cartridge 922 into a reclaimed frame.
In accordance with one aspect of the invention, the air permeable fabric used to construct the sleeve 1022 can be coated with antimicrobial metal oxide particles such as Titanium Dioxide (TiO2) in order to promote photocatalytic inactivation of microorganisms in the presence of UV light. Such particles can be formed directly into the fabric, or alternatively applied to the outer surface thereof by spraying or other suitable method.
The filtration membrane elements, such as cartridge 922, and sleeve 1022, employed in the modular furniture panels described and illustrated herein preferably include a substrate and a network of electrospun polymeric nanofibers deposited on the substrate. The network of electrospun polymeric nanofibers has a total polymer weight of 5 to 25% and the membrane has a minimum air filtration efficiency of between MERV 8 and MERV 16. Particularly, the membrane can have a minimum air filtration efficiency of MERV 8, MERV 9, MERV 10, MERV 11, MERV 12, MERV 13, MERV 14, MERV 15 or MERV 16.
In accordance with this aspect, the substrate material can comprise non-woven polyester fibrous or microfibrous material and/or a non-woven polypropylene fibrous material. Additionally or alternatively, the substrate material can comprise a polyester screen with mesh openings ranging from 50 to 1000 microns. The polymeric nanofibers can comprise polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), thermoplastic polyurethane (TPU), polypropylene (PP), or a similar thermoplastic material, have an average diameter of 50 to 500 nm, and create a layer of thickness of between 0 to 150 microns.
In accordance with this aspect, the polymeric nanofibers and/or the substrate can be coated with an antifungal, antibacterial, and/or antiviral agent. In such an instance, either the polymeric nanofibers and/or the substrate can be sprayed with non-spherical, spherical, or coral shaped metal nanoparticles.
Moreover, a protective layer can laminated or bonded to the membrane for structural support and the network of polymeric nanofibers can include multiple polymer types, which include multiple layers of different nanofibers, or multiple polymers co-spun together to form a blended layer.
While the subject disclosure has been shown and described with reference to preferred embodiments, those skilled in the art will readily appreciate that changes and/or modifications may be made thereto without departing from the spirit or scope of the present invention.
This application is a continuation of International Patent Application No. PCT/US2022/048825 filed Nov. 3, 2022, which claims priority to and the benefit of U.S. Provisional Application No. 63/275,069 filed 3 Nov. 2021, U.S. Provisional Application No. 63/275,086 filed 3 Nov. 2021, U.S. Provisional Application. No. 63/275,101 filed 3 Nov. 2021, and U.S. Provisional Application No. 63/304,933 filed 31 Jan. 2022, each of which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63304933 | Jan 2022 | US | |
| 63275069 | Nov 2021 | US | |
| 63275086 | Nov 2021 | US | |
| 63275101 | Nov 2021 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US2022/048825 | Nov 2022 | WO |
| Child | 18653657 | US |
