Plasma system for air purification and aerosol activation

Abstract

Devices, systems, and techniques for purifying gases or aerosols are disclosed. Such techniques can be utilized, for example, in conjunction with existing nebulizers or atomizers, or in conjunction with residential, commercial, or industrial HVAC systems. The device can include a housing configured to allow a gas or aerosol to pass through the housing from an inlet to an outlet. The device can include a dielectric barrier discharge (DBD) element positioned at or covering an end of an opening. The DBD element can be configured to generate a plasma and can be configured to allow a gas or aerosol to pass along or through the surface of the DBD element. When passing through the plasma, a bactericidal compound is created within the gas or aerosol, enabling the purification of the gas or aerosol. The purified gas or aerosol can then be sent, for example, to a mask, a room, etc.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit of U.S. Provisional Patent Application No. 63 / 350,539, filed on Jun. 9, 2022, the content of which is hereby incorporated by reference in its entirety.

[0002] Statement Regarding Federally Sponsored Research or Development This invention was made with government support under Grant No. DE - AC02 - 09CH11466 awarded by the Department of Energy. The government has certain rights in this invention.

[0003] This application relates to the use of low - temperature plasma for aerosol activation.

Background Art

[0004] This section is intended to introduce the reader to various aspects of the art that may be related to various aspects of the invention described and / or claimed below. This discussion is believed to be helpful in providing background information to the reader to facilitate a better understanding of the various aspects of the invention. Accordingly, these descriptions should be read from this perspective and it should be understood that they are not to be read as an endorsement of the prior art.

[0005] Plasma - activated aerosols can be used in various treatments, but conventional techniques require the use of noble gases such as Ar or He. The requirements for noble gas sources result in a complex situation that limits the portability of, for example, a system combining an integrated plasma - activation device and a nebulizer, increases the system size, and also involves significant additional costs.

Summary of the Invention

[0006] Various deficiencies of the prior art are addressed by the devices, systems, and techniques disclosed below.

[0007] In various aspects, an apparatus may be provided. The apparatus may include a housing. The housing may have a wall that defines an opening through the wall. The opening may be configured to allow a gas or aerosol to pass from an inlet through the housing to an outlet. The apparatus may include a dielectric barrier discharge (DBD) element positioned at or covering an end of the opening. The DBD element may be configured to generate a plasma. The DBD element may be configured to allow a gas or aerosol to pass along or through the surface of the DBD element.

[0008] The DBD element may include a conductive plate separated by a thin dielectric film and a grounded metal mesh. The DBD element may include a plurality of conductive wires configured in a mesh or mesh-like pattern. The DBD element may include a plurality of electrodes, at least one of which includes a plurality of fibers with a small diameter and a high aspect ratio. The DBD element may be coupled to at least a portion of the inner surface of the wall that defines the opening.

[0009] In some embodiments, the gas or aerosol may be a gas (such as air and may include oxygen). In some embodiments, the gas or aerosol may be an aerosol.

[0010] In various aspects, a system may be provided. The system may be a portable system. The system may be a non-portable system. The system may include the apparatus disclosed herein. The system may include a power source (such as a battery) operably coupled to the apparatus. The system may include an inlet channel operably connected to the inlet and configured to provide a path for directing at least one source of gas or aerosol to the apparatus. The system may include an outlet channel operably connected to the outlet and configured to provide a path for transporting the plasma-activated gas or aerosol away from the apparatus.

[0011] The system may include a gas or aerosol filter positioned in an outlet channel or an inlet channel. The system may include a fan positioned in the outlet channel. The system may include a heating and / or cooling element positioned in the outlet channel.

[0012] The inlet channel may be configured to receive return air from within the indoor space. The outlet chamber may be configured to return air to the indoor space. The inlet channel may be configured to receive return air from within the indoor space and outside air from the outdoor space.

[0013] The inlet channel may be operably coupled to a source of liquid. The system may include a nebulizer or atomizer configured to generate an aerosol using the source of liquid.

[0014] In various aspects, a method for purifying air and aerosol may be provided. The method may include providing an apparatus as disclosed herein. The method may include generating a plasma by passing an electric current through the apparatus. The method may include enabling a gas or aerosol to enter the inlet of the apparatus and pass through the plasma and out of the outlet.

[0015] In various aspects, a kit may be provided. The kit may include an apparatus as disclosed herein. The kit may include a filter. The kit may include a fan. The kit may include a heating and / or cooling element. Alternatively, the kit may include the apparatus disclosed herein, a liquid supply source or reservoir for liquid, a nebulizer or atomizer, and a power source.

[0016] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the general description of the invention given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

[0018] It should be understood that the accompanying drawings are not necessarily to scale and represent various features of the basic principles of the present invention in a somewhat simplified manner. Specific design features of a series of operations disclosed herein, for example, features such as the specific dimensions, orientations, positions, shapes of various illustrated components are, in part, determined by the particular intended use and operating environment. Certain features of the illustrated embodiments are enlarged or distorted compared to others for ease of visualization and clear understanding. In particular, thin features may be made thicker for clarity and explanation.

Embodiments for Carrying Out the Invention

[0019] The following description and drawings merely explain the principles of the present invention. Accordingly, it will be understood by those skilled in the art that, although not explicitly described or shown herein, various modifications that embody the principles of the present invention and fall within the scope of the present invention can be devised. Further, all examples listed herein are clearly intended solely for illustrative purposes to assist the reader in understanding the principles of the present invention and the concepts provided by the inventors for further advancing the art, and are not to be construed as being limited to such specifically listed examples and conditions. In addition, as used herein, the term "or" refers to a non-exclusive "or" (e.g., "otherwise" or "alternatively") unless otherwise indicated. Also, since some embodiments can combine with one or more other embodiments to form new embodiments, the various embodiments described herein are not necessarily mutually exclusive.

[0020] Numerous innovative teachings of this application will be described with particular reference to presently preferred exemplary embodiments. However, it should be understood that such embodiments merely provide a few examples of many advantageous uses of the innovative teachings herein. Generally, the descriptions made in the specification of this application do not necessarily limit the various inventions claimed. Further, some descriptions may apply to certain inventive features but not to others. Those skilled in the art and those who have obtained knowledge from the teachings herein will understand that the present invention is applicable to various other technical fields or embodiments.

[0021] This specification discloses a plasma system for air purification and aerosol activation. The plasma system disclosed for aerosol activation can be easily integrated into commercially available portable or desktop nebulizers to generate cold plasma in the ambient air and activate the mist flowing through the nebulizer tube on the way to the mouthpiece. The disclosed device is a compact and lightweight add-on that can be easily attached to the nebulizer tube. The techniques disclosed for the plasma system for air purification include several plasma source configurations that can be easily incorporated into the air flow paths within buildings such as residences and workplaces that are routinely occupied by people. The cold plasma of the two disclosed devices is shown as a very effective technique for significantly killing bacteria and inactivating viruses on surfaces without causing thermal damage or other damage. The disclosed techniques can also be employed for air purification.

[0022] The plasma device disclosed for aerosol activation can be integrated into a commercial nebulizer to enrich the water, solution, and drugs used in the nebulizer with reactive oxygen and / or nitrogen species (RONS).

[0023] The plasma activation device can be attached to a nebulizer and generate plasma-activated mist (PAMI). PAMI can be used to effectively reduce bacteria and viruses in the upper airway. To that end, by using the disclosed device, the oral cavity in addition to the throat is filled with plasma-activated aerosol. Due to its properties, the plasma-activated aerosol is uniformly dispersed and can reach not only the oral cavity and throat but also areas that are difficult to access, such as the nasal cavity. Plasma species can reduce the amount of bacteria and viruses throughout the upper airway and thus potentially prevent bacteria from spreading into the lungs.

[0024] PAMI has been shown to be effective in eradicating cancer cells and is disclosed as a postoperative treatment to remove the cancer cells remaining after surgery. Thus, the disclosed device can be used in oncological therapies (see "Effect of Plasma Activated Mist on Breast Cancer Cells" by M. El Shaer et al., IEEE Trans. Rad. Plasma Med. Sci, 2, 103 (2018)).

[0025] PAMI has also shown a fairly beneficial effect on seed germination after applying PAMI to wheat seeds. Thus, the disclosed device has potential applications in agriculture (see "Germination of Wheat Seeds Exposed to Cold Atmospheric Plasma in Dry and Wet Plasma-Activated Water and Mist" by M. El Shaer et al., Plasma Medicine, 10, 1 (2020)).

[0026] The disclosed technique is a scalable device and can also be added to room-sized nebulizers used, for example, to humidify or purify indoor air. PAMI can easily convert devices currently present in many households into personal disinfection and purification devices, especially in situations where a particularly gentle action is required, such as when applied to the skin and other sensitive surfaces. The antibacterial effect of the plasma-activated medium has been demonstrated so far.

[0027] The generation of PAMI has been investigated in several previous studies. In all cases, the plasma was created in a noble gas such as Ar or He. It was then introduced into the plasma to activate the mist from a nebulizer or atomizer. The disclosed device does not require flowing a noble gas to ignite the plasma and thus preferably does not include a noble gas source. Instead, the plasma is ignited in the ambient atmosphere. The add-on device is small, lightweight, and compact. This device is powered by a small power source (such as a source that can provide an AC voltage of up to 100 kV and a maximum current of 0.3 mA), and this device can also be lightweight and compact and can be integrated into the nebulizer package.

[0028] In various aspects, a device can be provided. Referring to FIG. 1, device 100 can include a housing 110. The housing can have a wall 119 that can have an outer surface 113 and an inner surface 114. The wall (which can be a side wall, for example) can define an opening 115 that extends through the housing. In some embodiments, the housing can be a tube or pipe.

[0029] The opening can form an inlet 116 at a first end 111 and an outlet 117 at a second end 112 opposite the first end. In this configuration, gas or aerosol can pass from the inlet through the housing to the outlet.

[0030] The device can include a dielectric barrier discharge (DBD) element 120 that can be positioned (or disposed) in the opening 115. In some embodiments, the DBD element is disposed at the first end of the housing. In some embodiments, the DBD element is disposed at the second end of the housing. In some embodiments, the DBD element can be disposed at an intermediate location between a distance of zero or more from the first end and a distance of zero or more from the second end.

[0031] The DBD element can be coupled to at least a portion of the inner surface 114 of the wall that defines the opening.

[0032] The DBD element can be configured to generate a plasma. The DBD element can be configured to allow a gas or aerosol to pass along or through the surface of the DBD element.

[0033] Referring to FIG. 2, the DBD element can include a conductive plate 210 and a grounded metal mesh 220 separated by a thin dielectric film 230. In some embodiments, the thickness of the dielectric film can be 5 mm or less. In some embodiments, the thickness of the dielectric film can be 4 mm or less. In some embodiments, the thickness of the dielectric film can be 2 mm or less. In some embodiments, the thickness of the dielectric film can be 3 mm or less. In some embodiments, the thickness of the dielectric film can be 1 mm or less. In some embodiments, the dielectric film can be a coating around the metal forming the metal mesh.

[0034] The conductive plate can be made of a metal (such as copper). The conductive plate can be made of a polymer. The conductive plate can be operably coupled to a power source 240.

[0035] The DBD element can include a plurality of conductive wires 221, 222 configured in a mesh or mesh pattern.

[0036] In some embodiments, the element can consist of a power-receiving conductive plate (e.g., made of flexible copper tape) and a grounded flexible metal mesh separated by a thin flexible dielectric layer or film (e.g., polyamide). The device can be powered by an AC power source. The device can be manufactured in a planar configuration and can also be reconfigured, for example, into a cylindrical configuration. Such a configuration can be optimal, for example, for air purification applications.

[0037] Referring to FIG. 3, the DBD element may include two or more wires 221 substantially oriented in a first direction and a plurality of wires 222 oriented in a second different direction. Each wire may include a conductive core 315 (such as copper or a conductive polymer, etc.) that can be surrounded by one or more non-conductive coatings 310 (such as a dielectric coating). The coating can be, for example, polytetrafluoroethylene (PTFE) and expanded polytetrafluoroethylene (ePTFE), as well as related materials, polysiloxane or other silicon-based polymer materials, or combinations thereof. When a current (e.g., from power supply 240) is applied to the conductive core, a plasma 320 can be created in the gas or aerosol (e.g., air circulating in a building or mist from a nebulizer) around locations where the distance 317 between the wires is zero or relatively small (e.g., 2 mm or less).

[0038] In a preferred embodiment, the DBD element may include two wires. For example, one embodiment referred to as a plasma "wisp" consists of two conductive fibers. A pulsed AC voltage is applied between these two wires. One or both of the wires can be coated in the form of an insulating material (e.g., a dielectric coating). A dielectric barrier discharge is formed along the dielectric surface.

[0039] Referring to FIG. 4, the DBD element may include at least one electrode including a plurality of fibers 410, 411 with a small diameter and a high aspect ratio. This can include, for example, a fabric such as velvet. A second electrode 430 may be present. The fibers can be coupled to a conductive plate 420. Each fiber can be the same, or some fibers can be different. In some embodiments, as seen in FIG. 3, at least one fiber 410 may include a conductive core with an outer non-conductive shell. In some embodiments, one or more fibers 411 may not include a conductive core. In some embodiments, one or more fibers 412 may include only a conductive core. The DBD element may also include a second grounded electrode 420. The fibers can be configured to allow gas or aerosol to flow through the plurality of fibers (440).

[0040] In some embodiments, a velvet material composed of small-diameter, high aspect ratio fibers can be used as part of the power electrode or the ground electrode or both. FIG. 4 shows an example of a disclosed configuration having a power electrode with fiber velvet and a planar ground electrode made of a bulk material. Air passes along the surface of the ground electrode and through the fibers. It is also possible to pass air along the fibers perpendicular to the ground electrode.

[0041] The gas or aerosol can be a liquid or can contain a liquid. The gas or aerosol can be a gas or can contain a gas (such as air and can contain oxygen). The gas or aerosol can contain an aerosol.

[0042] In various aspects, a system can be provided. The system can be a portable system. The system can be a non-portable system (for example, the system can be fixed to a ceiling, on a ground concrete pad, etc.). For example, referring to FIG. 5, system 500 can include device 100 disclosed herein.

[0043] The system can include a power source 510 (such as a battery) operably coupled to the device. The power source can provide an AC current.

[0044] The system can include an inlet channel 520 operably connected to inlet 116 and configured to provide a path 521 that directs at least one source 522 of gas or aerosol to the device.

[0045] In some embodiments, the gas or aerosol can be a liquid. The system can include a nebulizer or atomizer 523 configured to generate an aerosol using a liquid source, and the aerosol is provided to the inlet channel.

[0046] The system may include an outlet channel 530 operably connected to outlet 117 and configured to provide a path 531 for transporting plasma-activated gas or aerosol away from the device.

[0047] Referring to FIGS. 6 - 10, the system may include a gas or aerosol filter 610. The gas or aerosol filter may be disposed within the inlet channel (see FIG. 6). The gas or aerosol filter may be disposed within the outlet channel (see FIG. 7). The gas or aerosol filter may be disposed within an opening on the device (see FIGS. 8 - 10).

[0048] The system may include a fan 910. The fan may be positioned within the outlet channel (see FIG. 9). The fan may be positioned within an opening of the device (see FIG. 10).

[0049] The system may include a heating and / or cooling element 1010. The heating and / or cooling element may be positioned, for example, within the outlet channel (see FIG. 10), within an opening of the device, or within the inlet channel. The heating and / or cooling element may include one or more (for heating) electrical heating coils. The heating and / or cooling element may include a Peltier element (for heating and / or cooling). The heating and / or cooling element may include one or more plates and / or tubes containing a heat exchange fluid such as a refrigerant, glycol, etc. (for heating and / or cooling).

[0050] Referring to FIGS. 9 and 10, the apparatus may be configured to draw air from different locations. Referring to FIG. 9, in some embodiments, the inlet channel may be configured to receive air from a single source (e.g., to receive return air 920 from within an indoor space). The outlet chamber may be configured to discharge air to a single location (e.g., to return air 930 to the indoor space that received the air). Referring to FIG. 10, the inlet channel may be configured to receive air from multiple sources (e.g., to receive return air 920 from within an indoor space and outside air 1021 from an outdoor space). The inlet channel may include one or more ports 1020 configured to be coupled to each source of gas (here, air).

[0051] In some embodiments, a recycle loop is included. For example, referring to FIG. 11, in some embodiments, the apparatus may have multiple inputs and multiple outputs. The apparatus may receive air from a room 1100 and from outside air (e.g., from a location 1110 outside of the building in which the room is located). Further, the apparatus may receive air from a recirculation loop 1120.

[0052] Further, as seen in FIG. 11, one or more additional devices 1130 may be operably coupled in series (optionally). This device may have the same or a different design. For example, a first device (here, device 100) may have a flex DBD element and may not have a filter, and a second device (here, additional device 1130) may have a weave DBD element and a filter.

[0053] The output from the apparatus may be split such that a portion may be returned to the room 1100 and a portion may enter the recirculation loop 1120. The amount of gas or aerosol flowing through the recirculation loop can be controlled using any known technique.

[0054] Example 1 To fabricate one embodiment of the disclosed device (herein referred to as a flexible printed circuit design, sometimes called a "flex DBD" design), printed circuit board technology was applied to manufacture a thin dielectric layer (e.g., polyimide with a thickness of 100 microns) sandwiched between two thin metal layers (e.g., copper with a thickness of 30 microns or less). The size of the sheet can vary. One of the metal layers is in a mesh form (with typical square or circular openings having dimensions of 1 mm or less and gaps between the meshes of 1 mm or less).

[0055] Referring to FIG. 12, the mesh layer 1200 is electrically grounded and the other metal layer 1201 is connected to an AC power source (typically with an amplitude of 1 - 5 kV and a frequency of 6 - 60 kHz). When the power source is turned "on", plasma 1210 is generated in the holes of the mesh (where 1220 is the structural part of the mesh layer and the space between the structural parts represents the mesh).

[0056] Flex DBD can generally operate at atmospheric pressure and room temperature in ambient air without any additional gas flow at a relatively low power density (e.g., up to 0.5 W / cm 2 ).

[0057] When the flex DBD sheet is in a tubular configuration, since the mesh layer is directed towards the central axis, the plasma is generated on the inner surface of the tube. This device can then be added as an extension to a nebulizer tube. Subsequently, additional tubes (e.g., outlet channels) to a mouthpiece or mask can be added.

[0058] In addition to the use of the surface flex DBD, a plasma fabric can be used to line the inside of the tube. The plasma fabric is a loom-woven fabric that uses two long fibers made from a soft insulating polymer material with a thin conductive core (see, for example, FIG. 3). Each fiber is completely insulated and can be powered by a battery-powered power source. The power source can be incorporated into the body of the nebulizer or the body of the device. The size of the fabric can be changed as needed and only requires one electrical connection. This fabric can be placed inside the tube, as shown in FIG. 11, and further, over the opening (e.g., covering opening 116) such that the mist passes through the fabric as it exits the nebulizer, providing additional options. Thus, in some embodiments, the DBD element can be coupled to the end of the device.

[0059] Example 2 Referring to FIG. 12, two different device embodiments (the "Flex" and "Weave" in FIG. 12) were used as both dry-cultured tissue ("dry") and liquid-cultured tissue ("wet") to purify a gas or aerosol containing the human herpes simplex virus (HSV). As can be seen, the virus concentration was reduced by up to 99% for the dry-cultured tissue and 99.7% for the liquid-cultured tissue. Similar results were found for the purification of SARS-CoV2, with a 90 - 95% reduction seen for both devices.

[0060] Example 3 Various embodiments operate by creating a bactericidal compound from the gas or aerosol passing through the plasma. For example, a plasma-activated mist was tested for chemical reactivity by measuring the concentration of hydrogen peroxide (H2O2) generated in the plasma-activated mist (e.g., via the peroxone process) using, for example, a water test strip. Hydrogen peroxide is typically associated with plasma-induced reactivity and beneficial bactericidal effects. The addition of reactive nitrogen species can enhance the bactericidal efficiency of hydroxyl groups and other oxygen species.

[0061] This test showed that exposing mist to plasma (including the apparatus of Example 1) resulted in 10 ppm (mg / L) of H2O2. Flex and Weave apparatuses of similar size produce reactive species of similar concentration.

[0062] In its current form, the disclosed apparatus can be easily integrated into commercial medical nebulizers. The apparatus can be dispensed as an add-on to a nebulizer and requires only a very simple tube adapter for integration. The apparatus can be employed in larger-scale mist generators, such as those used in agriculture, for example. The disclosed apparatus can also be used for the rapid sterilization of a wide and complex surface - for example, the washing of leafy vegetables in the home or in agriculture.

[0063] In the disclosed apparatus, rather than sterilizing the surface, the chemical reaction is entrusted to small droplets that are highly likely to disperse and reach small gaps, thus sterilizing complex surfaces with intricate topologies that are inaccessible by other methods.

[0064] Flexible or conformable DBD apparatuses generate a uniform low-temperature plasma that can be applied for sterilization and personal hygiene purposes. The apparatus can be easily fabricated into a desired geometry for mounting on curved surfaces, such as door handles, for example. To date, it has been shown that the low-temperature plasma of DBD discharge has beneficial biological effects and promotes significant bacterial killing and virus inactivation without causing thermal damage or other damage.

[0065] The effect of the plasma by flexible DBD can be enhanced by various liquids that enhance the plasma-induced chemical reactivity. The apparatus is very simple to operate, constructed from inexpensive components, and powered by a simple and compact power source. The low-temperature plasma apparatus generates a low-temperature plasma that can purify an air stream from viruses and bacteria.

[0066] This specification discloses several plasma source configurations that can be easily incorporated into the air flow paths within buildings that are routinely occupied by people, such as residences and workplaces. This includes the application and development of some existing plasma sterilization devices. The disclosed techniques include several devices and several different configurations of existing devices. Existing plasma devices are not intended for industrial-scale purification.

[0067] The disclosed techniques can be employed to purify gases (especially air) from bacterial, viral, and some chemical contaminants, and can also be used in air ventilation systems with heating and / or air conditioning with recirculation in commercial buildings including residences and hospitals. It can also be used as part of a portable system for purifying the air within rooms including hospital rooms.

[0068] The disclosed techniques are based on multiple discharge plasma sources. The disclosed multiple discharge systems can include, but are not limited to, scalable and flexible systems of multiple cavities or multiple gaps, including in some configurations the enhancement of the electric field within the discharge gap around small-diameter fiber electrodes. These systems can use a dielectric barrier to limit the discharge current.

[0069] Variations of the disclosed designs can include, for example, the use of existing flexible dielectric barrier plasma sources (Flex DBD), configurations of woven fiber designs (Plasma Weave), and dielectric barrier configurations that utilize electric field enhancing fibers in materials such as velvet.

[0070] Advantages of these designs include the ability to employ air filters of various shapes, such as corrugated shapes (Flex DBD and Plasma Weave), the ability to reduce the ignition voltage of the discharge (Plasma Velvet), scalability, safety, and portability.

[0071] The disclosed device can be used as a stand-alone or portable unit and can also be integrated into existing air circulation systems such as ventilation, heating, and air conditioning systems.

[0072] Some examples of the disclosed configurations for purifying air using flexible DBD, plasma wick, and plasma velvet are described below. In all configurations, the air to be treated can be passed through the plasma device the number of times required to achieve the desired level of sterilization. Air that is considered to be contaminated by aerosols containing viruses or bacteria, or by suspended particles, passes through the plasma-based purification device and is pumped back into the occupied space.

[0073] Referring to FIG. 9, it can also be seen that in some embodiments, the device can optionally include within the device one or more additional DBD elements 930, preferably in series with the DBD element 120. The various DBD elements can be the same. The various DBD elements can be different.

[0074] The flexible DBD device is more suitable for applications where a large area is to be treated over a long period of time. Such a device can generate a uniform plasma at low temperature in the ambient atmosphere. The fact that the flexible DBD can be easily fabricated by printed circuit board (PCB) technology and its effectiveness as an antibacterial treatment in wound healing has been demonstrated so far. This device is safe to touch due to a very low current of less than 1 mA for the user and a temperature T slightly higher than room temperature (22 °C < T < 40 °C).

[0075] The plasma wick is easily scalable over a wide range, flexible, and can be easily incorporated into existing air filtration systems and used in any geometric shape. For example, it can cover the inner surface of a pipe to prevent contaminants from adsorbing on the surface of the air duct. The plasma wick can operate as a one-barrier discharge or a two-barrier discharge with one or two insulated wires.

[0076] Devices based on arrays of high aspect ratio, small diameter fibers can be geometrically positioned to reduce the discharge ignition voltage. Fiber materials for this device are available depending on conductive and non-conductive properties, as well as combinations of conductive and non-conductive fibers.

[0077] In various aspects, methods for purifying air and aerosols can be provided. Method 1400 can include, at 1410, providing a device disclosed herein. The method can include, at 1420, generating a plasma by passing an electric current through the device. The method can include, at 1430, allowing a gas or aerosol to enter the inlet of the device and pass through the plasma and out of the outlet.

[0078] In some embodiments, the method can include, at 1440, directing a gas or aerosol to a location within a building or to a mask. In some embodiments, the method can include, at 1450, discharging and recycling at least a portion of the gas or aerosol from the outlet to the inlet.

[0079] In some embodiments, the method can include, at 1460, controlling how much gas or aerosol is recycled, for example based on a measured flow rate of the gas or aerosol. This can allow the system to control the average length of time the gas or aerosol is exposed to the plasma, thereby controlling the effectiveness of the system.

[0080] In various aspects, a kit can be provided. The kit can include a device disclosed herein. The kit can include a filter. The kit can include a fan. The kit can include a heating and / or cooling element. Alternatively, the kit can include a device disclosed herein, a liquid supply source or reservoir for a liquid, a nebulizer or atomizer, and a power source.

[0081] For the systems, methods, apparatuses, mechanisms, techniques, and parts thereof described in this specification with respect to various figures, various modifications may be made, and such modifications are assumed to be within the scope of the present invention. For example, in various embodiments described in this specification, a particular order of steps or an arrangement of functional elements is shown, but within the context of various embodiments, various other orders / arrangements of steps or functional elements may be utilized. Further, modifications to embodiments may be considered individually, and various embodiments may use multiple modifications simultaneously or sequentially, or use composite modifications, etc.

[0082] Although various embodiments incorporating the teachings of the present invention have been shown and described in detail herein, those skilled in the art can readily devise many other various embodiments that still incorporate these teachings. Accordingly, while the foregoing is directed to various embodiments of the present invention, other and further embodiments of the present invention may be devised without departing from its basic scope. Accordingly, the proper scope of the present invention should be determined in accordance with the claims.

Claims

1. An apparatus comprising: A housing having a wall, the wall defining an opening therethrough, the opening being configured to allow gas or aerosol to pass from an inlet through the housing to an outlet; and A dielectric barrier discharge (DBD) element positioned at or covering an end of the opening, the DBD element being configured to generate plasma and configured to allow the gas or aerosol to pass along or through the surface of the DBD element.

2. The apparatus according to claim 1, wherein the DBD element comprises a conductive plate separated by a thin dielectric film and a grounded metal mesh.

3. The apparatus according to claim 1, wherein the DBD element comprises a plurality of conductive wires configured in a mesh or mesh pattern.

4. The apparatus according to claim 1, wherein the DBD element comprises a plurality of electrodes, at least one of the electrodes comprising a plurality of fibers with a small diameter and a high aspect ratio.

5. The apparatus according to claim 1, wherein the gas or aerosol is a gas.

6. The apparatus according to claim 1, wherein the gas or aerosol comprises an aerosol.

7. The apparatus according to claim 1, wherein the DBD element is coupled to at least a portion of an inner surface of the wall defining the opening through the wall.

8. A system comprising: The apparatus according to claim 1; A power source operably coupled to the apparatus; An inlet channel operably connected to the inlet and configured to provide a path for directing at least one source of gas or aerosol to the apparatus; and An outlet channel operably connected to the outlet and configured to provide a path for transporting the plasma-activated gas or aerosol away from the apparatus.

9. The system according to claim 8, further comprising a gas or aerosol filter positioned in the outlet channel or the inlet channel.

10. The system according to claim 8, further comprising a fan positioned in the outlet channel.

11. The system according to claim 8, further comprising a heating and / or cooling element positioned in the outlet channel.

12. The system according to claim 8, wherein the inlet channel is configured to receive return air from the indoor space, and the outlet channel is configured to return air to the indoor space.

13. The system according to claim 12, wherein the inlet channel is configured to receive return air from the indoor space and fresh air from the outdoor space.

14. The system according to claim 8, wherein the inlet channel is coupled to a source of liquid.

15. The system according to claim 14, further comprising a nebulizer or atomizer configured to generate an aerosol using the source of liquid.

16. The system according to claim 8, wherein the power source is a battery.

17. The system according to claim 8, wherein the system is portable.

18. A method for purifying air and aerosol, comprising: providing the device according to claim 1; generating plasma by passing an electric current through the device; enabling a gas or aerosol to enter the inlet of the device and pass through the plasma and exit through the outlet.

19. A kit comprising: the device according to claim 1; a filter; a fan.

20. The kit according to claim 19, further comprising a heating and / or cooling element.

21. A kit comprising: the device according to claim 1; a liquid supply source or reservoir for liquid, a nebulizer or atomizer; a power source.

Images