CN113566367A

CN113566367A - Air disinfection system and air purification method

Info

Publication number: CN113566367A
Application number: CN202110712177.4A
Authority: CN
Inventors: 樊华; 郑婉仪; A·祖尔比尔
Original assignee: Maydale Co ltd
Current assignee: Maydale Co ltd
Priority date: 2020-10-26
Filing date: 2021-06-25
Publication date: 2021-10-29

Abstract

Disclosed is an air sterilizer system, including: an air inlet for receiving an air flow into the system and an air outlet; the air outlet is for exhausting the airflow from the air sanitizer system with a conduit between the air inlet and the air outlet. The system comprises: an ioniser disposed within the conduit in the direction of gas flow and having a charge reduction phase, in use, in which the ioniser produces a first air ionisation region in which aerosol and/or suspended particles in the incoming air are charged; and the charge reduction phase is used to create a first charge reduction region. The charged aerosol and/or particles are attracted to the charge reduction stage as they pass through the stage and are at least partially discharged upon contact with the charge reduction stage, the charging and subsequent discharging removing, deactivating or eliminating at least some of the aerosol and/or suspended particles.

Description

Air disinfection system and air purification method

Technical Field

The present disclosure relates to air purification by using ionization of air to disinfect, remove, or both, suspended particles and/or aerosols. One particular application is the disinfection and/or removal of airborne pathogens, aerosols containing pathogens, or both.

Background

Currently, there are systems that utilize negative ions for air purification. Some of these systems are primarily used to increase the concentration of negative ions in the air. However, simply increasing the concentration of negative ions does not improve the adsorption or removal of impurities or other particles (e.g., aerosols containing infectious agents, particulate matter, viruses, bacteria, etc.) from the air.

It will be understood that, if any prior art is referred to herein, such reference does not constitute an admission that the prior art forms part of the common general knowledge in the art in australia or any other country.

Disclosure of Invention

In one aspect, disclosed herein is an air sanitizer system comprising: an air inlet for receiving an air flow into the air sanitizer system and an air outlet; the air outlet is for exhausting the airflow from the system with a duct between the air inlet and the air outlet. The air sanitizer system includes: an ioniser and a charge reduction stage (stage) disposed within the conduit in the direction of gas flow, the ioniser creating, in use, a first air ionisation zone within the conduit, aerosol and/or suspended particles in the incoming air being charged; and a charge reduction stage for creating a first charge reduction region. The charged aerosol and/or particles are attracted to the charge reduction stage as they pass therethrough and are at least partially discharged upon contact with the charge reduction stage, with charging and subsequent discharging removing, inactivating or eliminating at least some of the aerosol and/or suspended particles.

In some forms the ioniser comprises a plurality of electrodes distributed within the first ionisation region and which, in use, are charged to generate negative ions to charge aerosol and/or suspended particles in the incoming air passing through the first air ionisation region.

In some forms the electrodes are charged to provide a corona discharge.

In some forms, the electrodes are plated with silver, gold, copper, or platinum.

In some forms, adjacent electrodes are separated by a distance of at least 0.5 cm.

The air disinfection system may include one or more additional ionization zones.

In some forms at least two of the two or more ionization regions are configured to charge the aerosol and/or suspended particles in the incoming air to different potentials.

In some forms the ionisation region closest to the inlet is configured such that the aerosol and/or suspended particles in the incoming air are charged to provide a minimum level of ionisation compared to the other ionisation region or regions.

The air sanitizer system may include one or more additional charge reduction stages.

In some forms at least two of the charge reduction stages and two of the ionization regions within the conduit are arranged in an alternating manner.

In the first charge reduction phase, a charge reduction device may be provided, which is connected to ground or to a power supply.

In some forms the charge reduction device includes a structure having a textured surface.

In some forms, the material of the charge reduction device includes an antimicrobial or sterilization additive.

The air disinfecting system may comprise at least two charge reducing devices arranged in series in the duct, the two charge reducing devices having different electrical potentials.

The air sanitizer system may include at least one outlet ionization zone disposed adjacent the outlet.

One or more light sources may be installed in the air disinfection system.

The air sanitizer system may include an air pressure generating device for driving the air flow.

The air sanitizer system may be retrofitted into existing building, transportation, or vehicle air circulation systems.

In a second aspect, disclosed herein is a method of air purification, comprising: generating air pressure to draw an air flow through the flow path; providing positive or negative ions in the flow path to charge aerosol and/or suspended particles in the flow path; and changing the potential of at least some of the charged aerosols and/or suspended particles.

The method may comprise placing a device in the flow path, the device having a surface connected to electrical ground, or to which a potential is applied, the potential being set at a level to cause the change in potential of the at least some charged aerosols and/or suspended particles, the device being adapted to cause the airflow to pass therethrough.

The method may comprise further charging the particles after said change in potential of at least some of the charged aerosol and/or suspended particles.

Drawings

Embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which:

fig. 1 is a schematic view showing an air cleaning apparatus according to an embodiment of the present invention;

fig. 2 is a schematic view showing an air cleaning apparatus according to another embodiment of the present invention;

fig. 3 is a schematic view showing an air cleaning apparatus according to still another embodiment of the present invention;

fig. 4 to 9 depict examples of different arrangements of ionization and charge neutralization regions;

FIG. 10 is a schematic view of the embodiment shown in FIG. 2 and a control and power supply apparatus;

FIG. 11(a) is an experimental setup for testing the effectiveness of an air purification device;

FIG. 11(b) is a diagram of the atomizer used in FIG. 11 (a);

FIG. 12(a) is a table showing the sequence of component switching in a prototype experiment using SARS-CoV-2 aerosol;

fig. 12(b) is a photograph of a 96-well plate after testing with the negative electrode turned off, wherein 85 of the 96 wells captured infectious aerosol as shown by the viral cytopathic effect (CPE) shown by reduction of crystal violet staining;

fig. 12(c) is a photograph of a 96-well plate after testing with the negative electrode turned on, wherein 0 of the 96 wells captured infectious aerosol as shown by the reduction of viral cytopathic effect (CPE) as shown by crystal violet staining, indicating 100% removal of infectious aerosol as compared to fig. 12 (b);

FIG. 13 is a table showing the sequence of component switching in prototype experiments using Getah virus aerosols;

fig. 14(a) is a photograph of a 96-well plate after testing with the negative electrode turned off, wherein 90 of the 96 wells captured infectious aerosol as shown by the viral cytopathic effect (CPE) shown by reduction of crystal violet staining;

fig. 14(b) is a photograph of a 96-well plate after testing with the negative electrode turned off, with 0 of the 96-wells capturing infectious aerosol as shown by the reduction in crystal violet staining shown by viral cytopathic effect (CPE); and

FIG. 15 is a schematic diagram depicting an air sanitizer system installed in a prior art system in which there is airflow.

Detailed Description

In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. The illustrative embodiments described in the detailed description depicted in the drawings are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the present subject matter. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are contemplated in the present disclosure.

There is now increasing evidence that aerosols do present an infection risk, particularly in the environment of high aerosol generating processes (e.g., some ear, nose, and throat processes) or during high aerosol generating activities (e.g., coughing, sneezing, vigorous movement, shouting, singing), even wearing an N95 mask does not completely block simulated transmission. In certain environments, aerosol transmission may be considered more likely, particularly in poorly ventilated enclosed spaces, such as certain hospital environments, aircraft, and the like. An air decontamination system that can remove infectious aerosols may in some cases make a significant contribution to reducing the risk of SARS-CoV-2 transmission.

Described herein is a system and method for air purification that utilizes ionization of air to remove, eliminate or inactivate infectious aerosols or suspended particles or contaminants, particularly airborne organic contaminants such as airborne pathogens, or a combination thereof. The system will draw in ambient air for cleaning and then blow out the treated air. The system may be a stand alone unit. However, the same concept may also be incorporated into other systems where airflow is present or expected to be generated, such as air conditioning systems or air filtration or circulation systems. These other systems may themselves be stand alone units or may be integrated within a larger structure (e.g., a building, an aircraft, etc.). These other systems may also be part of a wearable device (e.g., a personal protective equipment). Potential applications may be found, for example, in the home, commercial or clinical setting. Particular applications may also exist in transportation systems, particularly those that confine passengers in an enclosed space during travel.

In other embodiments, the concept may be incorporated into a wearable device, such as a Personal Protection Equipment (PPE), for generating a "clean" airflow-i.e., an airflow from which infectious aerosols or other contaminants or both are at least partially removed, eliminated or inactivated-to supply to a PPE wearer.

Hereinafter, when used, the term "particles" is generally considered to include particles of various substances, such as viruses or bacteria, and other organic or inorganic contaminants suspended in an air stream.

FIG. 1 depicts an air sanitizer system 100 according to one embodiment. The system 100 includes a housing 101, the housing 101 providing a structure in which a number of components are mounted. The housing 101 is configured to provide one or more air inlets 102 and one or more air outlets 103, air being drawn into the housing 101 through the one or more air inlets 102 and air being expelled from the housing 101 through the one or more air outlets 103. An airflow path is thereby defined within the housing to direct airflow from the one or more inlets 102 to the one or more outlets 103. In fig. 1, a fan 106 is provided to provide a negative pressure for drawing in air. Here, the fan 106 is shown to include an axial flow impeller mounted in the housing 101. Such an arrangement may help to reduce the required size of the housing.

It should be understood that in other embodiments including fans, the fans need not be located near the outlet as shown in fig. 1, so long as they provide the pressure necessary to create or promote airflow. In addition, the one or more inlets 102 need not be disposed on a sidewall of the housing 101 adjacent the airflow path as shown in FIG. 1. One or more inlets 102 may alternatively be provided on an end wall along the airflow path (see, e.g., fig. 4-8). Similarly, one or more outlets 103 may be provided in a side wall of the housing rather than an end wall as shown in FIG. 1.

Adjacent the inlet 102 are a plurality of electrodes 104 which, in use, will be negatively charged by electrical connection to a negative voltage module (not shown) configured to provide negative charge to the electrodes 104. A power supply module (not shown) for energizing the electrodes 104 may be located outside the housing 101. The power module may be controlled to regulate the voltage level.

The electrode 104 is configured to generate a corona discharge to generate negative ions. The incoming aerosol and/or particles, which are initially electrically neutral as the airflow enters the housing 101, will be attracted to and charged by the negative ions upon contact therewith, and thus charged by the negative ions. The space within the housing 101 where negative ions are generated to charge aerosols and/or particles may therefore also be referred to as an ionization chamber or ionization region 105. The electrodes 104 in the ionization chamber 105 that are arranged to charge the aerosol and/or particles may also be referred to as ionizing electrodes 104.

Ionizing electrode 104 may be positioned uniformly around the housing wall within ionization chamber 105, but this is not strictly required. Nor is it strictly required that the ionizing electrodes be aligned in pairs as shown in fig. 1. Preferably, adjacent pairs of electrodes are sufficiently spaced from each other so as to minimize ozone generation.

The voltage of the power supply should be selected such that it is high enough to generate a sufficient concentration of negative ions within the ionization chamber 105 to charge most of the incoming aerosol and/or particles, but still needs to be at a level that minimizes ozone production.

The charge reduction stage 107 is positioned between the plurality of electrodes 104 and the one or more outlets 103, and thus between the ionization chamber 105 and the one or more outlets 103. Accordingly, the ionization chamber 105 may also be considered to terminate at a charge reduction zone 108 where the charge reduction phase 107 is located. It will be appreciated that the charge of the charged aerosol and/or particles may be neutralized depending on the amount of charge reduction achieved by the charge reduction stage 107. Thus, in some cases, the charge reduction phase 107 may also provide charge neutralization.

The charge reduction or neutralization stage 107 will include a device formed of a conductive material and thus is a conductive device. The purpose of the charge reduction or neutralization device 107 is to reduce or neutralize the charge in those charged aerosols and/or particles, such as but not necessarily pathogens, that come into contact with the charge reduction or neutralization stage 107 as they move with the airflow. In doing so, the charge reduction or neutralization stage 107 causes a change in the potential of at least some of the charged aerosols and/or particles that will be electrically attracted to the charge reduction stage 107 for removal from the airflow. In response to such changes, the change in electrical potential may cause electrons to temporarily flow to or from the aerosol and/or particles to reduce or neutralize the electrical potential of the aerosol and/or particles.

The potential level of the charged aerosol and/or particles (which have been in contact with the charge reduction phase 107) may change instantaneously, suddenly or rapidly, so that instantaneous, sudden or rapid temporary electron discharge occurs in the aerosol and/or particles, or instantaneous, sudden or rapid temporary electrons flow into the aerosol and/or particles. This discharge or influx is desirably continued until the aerosol and/or particles are neutralized or until the aerosol and/or particles are physically separated from the charge reduction stage 107.

In most embodiments, the charge reduction or neutralization stage 107 will provide a means of grounding. However, the charge reduction or neutralization stage 107 may provide a means of being charged to a non-zero potential.

More generally, the charge reduction or neutralization device 107 will be at a voltage (zero, positive or negative) that will result in a reduced level of charging in the charged aerosol and/or particles. For example, when the aerosols and/or particles are negatively charged, the potential of the charge reduction or neutralization stage 107 is less negative (i.e., more positive) than the charged aerosols and/or particles to stimulate a rapid, near instantaneous electrical discharge, which has the effect of inactivating or eliminating or removing infectious aerosols or pathogens. Similarly, where the aerosol and/or particles are charged by a positive charge, the charge reduction or neutralization device 107 can be set to a potential that will reduce the positive charge and also stimulate the aforementioned discharge or influx to inactivate, eliminate or remove the pathogen.

The charge reduction or neutralization stage 107 is configured to provide holes or channels therethrough to allow air to pass through. The charge differential between the charged aerosols and/or particles (e.g., pathogens, dust, etc.) and the surface of the charge reduction device 107 causes the charged aerosols and/or particles (via ionized ions) to be attracted to the device surface and discharged. The charge reduction, and possibly neutralization, also has the benefit of reducing the release of ions from the device.

The following examples use negative ions, negatively charged incoming aerosols or suspended particles. For convenience, the charge reduction or neutralization stage 107 is referred to as the charge reduction stage 107. The surface of the charge reduction stage 107 may be bombarded by charged aerosols and/or particles in the gas flow path. These surfaces attract more negatively charged aerosols and/or particles by their relatively positive charge. Thus, the charge reduction stage 107 will be configured to present a sufficiently large surface area so as to "neutralize" (or charge less) as much of the charged aerosol or suspended particles as possible, preferably without impeding air flow or causing substantial resistance to air flow.

To increase the surface area available for contact, the surface presented by the charge reduction stage 107 may preferably be textured, for example a rough rather than smooth surface. The surface may be provided with protrusions, ridges, grooves, etc. It will be appreciated that the exact geometry or configuration of the charge neutralizing means is not critical as long as the above general requirements are met. The charge reduction stage 107 may include one or more substantially planar devices, such as a mesh extending in a plane through the cross-section of the flow path. The charge reduction stage 107 may alternatively include one or more non-planar devices, each having a non-negligible or thicker thickness in the direction of the flow path. The charge reduction phase 107 may have a regular or irregular shape. For example, it is possible to use a fibrous or net-like structure, such as steel wool or a sponge-like device. Further examples include other three-dimensional structures such as cages or three-dimensional matrices. Combinations of the foregoing configurations may be used.

Any conductive material may be used, such as conductive metals, conductive polymers, and the like. It is also possible to select materials with additional antibacterial, antimicrobial or antiviral properties, such as silver or copper or alloys thereof, or possibly to coat, electroplate or dope the materials with disinfectant properties.

When the aerosol and/or suspended particles are inhaled into the housing 101, the aerosol and/or suspended particles are charged in the ionization region 105. Any known ionization technique may be used to provide ionization. For example, ionizers currently available on the market utilize corona discharge of electrodes to ionize molecules in the air. Various electrode configurations are known that are capable of providing corona discharge, and in embodiments of the invention, the voltage is controlled to cause ionization with minimal or no ozone generation.

The now charged aerosols and/or particles will continue to be drawn by the air pressure towards the one or more outlets 103 and thus into the charge reduction zone 108 where the charged aerosols and/or particles may come into contact with the surface of the charge reduction stage 107. Upon such contact, an electron discharge may flow from the charged aerosol and/or particles (if charged by negative ions) to the surface of the charge reduction stage 107 due to the electrical difference between the charged aerosol and/or particles and the surface of the charge reduction stage 107. The temporary electrical current thus generated changes the potential of the charged aerosol and/or particle and also acts to inactivate or eliminate the aerosol and/or particle (e.g., airborne pathogens). The electrical attraction of the charged aerosols and/or particles to the charge reduction stage 107 may also remove at least some charged species, such as aerosols or particles, from the airflow.

Equipment prototypes two different viruses from different genera have been tested in a separate PC3 laboratory for SARS-CoV-2 and a PC2 laboratory for Getah virus. In the prototype tests performed, one experiment showed a 100% reduction in infectious coronavirus (SARS-COV-2) aerosol and another showed a 100% reduction in infectious aerosol for Getah virus. The experiments and results will be disclosed in more detail later herein.

However, it is contemplated that the disclosed embodiments are also effective against at least some other types of pathogens. Both the charging and reduction steps, the pathogen particles or viral aerosol can be inactivated or eliminated and can be removed. Thus, by having these steps, sterilization is more effective than systems using ionization alone. As shown in laboratory testing, the use of charging and potential reduction steps or stages can result in significant or complete removal, inactivation, or elimination of infectious material without the use of UV light.

The treated gas stream will be drawn from the charge reduction zone 108 by gas pressure, continuing at the charge reduction zone 108 towards the one or more outlets 103. An additional negatively charged electrode 109 may optionally be provided within the housing 101 between the charge neutralization zone 108 and the outlet 103 to re-ionize the air before it is exhausted. The further electrodes 109 are typically charged to a lower voltage than the voltage generated by the ionizing electrode (for the initially charged aerosol and/or particles). Preferably, the further electrode 109 will be charged to a level that minimizes the occurrence of static electricity. A sensor such as ozone sensor 110 or ion sensor 111 may optionally be provided at or near one or more outlets 103 to detect ozone or negative ion levels in the exhausted air.

As shown in fig. 2, the system 100 may optionally include one or more devices to provide internal sterilization in the system 100. These devices function by destroying infectious agents, whether in infectious aerosols or other pathogenic particles. These devices may be used to destroy infectious agents in aerosols or infectious particles that have been removed from the gas stream by electrical attraction to the charge reduction stage 107.

One such device may be provided with one or more ultraviolet (e.g., UV-C) lamps 112. If these lamps are included, one or more covers 113 will also be provided for safety purposes to block UV light from escaping and avoid potentially creating safety hazards. In the depicted embodiment, the cover 113 is arranged to also define a path for air flow, as indicated by the dashed arrows. These devices are not required for the removal, inactivation, or elimination of infectious agents in the gas stream. Another device that may be included is a heating module (not shown) for heating the system or at least a portion thereof to a sufficiently high temperature and for a sufficiently long time to destroy the infectious agent. For example, one or more heating elements may be provided to temporarily heat the interior of the system to 90 ℃ or higher, but below a temperature that may interfere with the structure or function of the rest of the system.

Another device that may be provided is a chemical disinfection device for applying a chemical to the charge reduction stage to chemically destroy infectious agents.

If included, the device may remain on during the operation of the charging and charge reduction processes to destroy infectious agents in real time. Alternatively or additionally, the device may be turned on when the charging and charge reduction processes have been turned off.

The above options may also be provided in other embodiments disclosed in this specification.

In embodiments disclosed herein, the system 100 may optionally include a filtering device 114 to capture larger particles, such as dust, in the airflow. The filter device 114 may additionally capture smaller or finer particles. The selection of the filtering function may be selected by the skilled person. Fig. 2 shows an example in which the system 100 includes a filtering device 114 located near the air inlet 102. In other embodiments, two or more filtration devices 114 may be included. Multiple filtration devices may be positioned at different portions within the housing 101. These filtration devices may be configured to provide different filtration functions, such as capturing large particles, small particles, or fine particles, or aerosols, or a combination of two or more of the foregoing. In fig. 2, the filter device 114 is positioned adjacent to one or more air inlets 102. However, it is additionally or alternatively possible for the filter device to be arranged elsewhere. For example, one or more filtering devices may be disposed within the charge reduction region 108. For example, the charge reduction stage 107 itself may provide an air filtration device to perform the dual functions of air filtration and charge reduction. The charge reduction stage 107 may also be made of a material that itself injects an anti-viral or anti-bacterial agent (e.g., silver).

In fig. 1 and 2, charge reduction region 108 is defined by the physical space occupied by charge reduction phase 107. There may be two or more cells in the system 100 with charge reduction stages 107 to provide different charge neutralization regions. Charged aerosols or particles (by ionized ions) that pass through the charge reduction stages 107 without contacting the surface of one of the charge reduction stages 107 may contact the next charge reduction stage 107.

Furthermore, the multiple cells of the charge reduction phase 107 may have different potentials. For example, a charge reduction or neutralization device 107 disposed further back in the flow path (i.e., closer to the outlet 103) may be configured to provide a greater potential difference relative to the charged aerosol and/or suspended particles than the previous charge reduction stage 107. Thus, a stronger discharge current can be expected when contacting a charged aerosol or particle. Thus, aerosol or airborne particles that are missed by one of the charge reduction stages 107 or that are not inactivated by contact with the charge reduction stage 107 may be removed, eliminated or inactivated by a subsequent, possibly "stronger" charge reduction stage 107.

The embodiment shown in fig. 1-3 includes an ionization region 105 followed by a charge reduction region 108, and then optionally other ionization regions near the outlet 103. In further embodiments, multiple ionization regions 105, or multiple charge reduction regions 108, or both, may be included. Two or more of the multiple ionization regions may have different "intensities", i.e., ionization electrodes therein are charged to different voltages. There is no requirement that the different voltages from inlet to outlet should be increased or decreased. For example, when the ionizing electrode is a needle electrode, the voltages at the tip of the electrode may be-5 KV (kilovolts), -6.5KV, -7KV, -5KV, or these voltages may be-5 KV, -5.5KV, -6KV, -6.5KV, or these voltages may be-7 KV, -10KV, -5KV, or these voltages may be-10 KV, -7KV, -6KV, -5KV, in the four ionization regions from the inlet to the outlet. It is possible to provide the ionization regions with other voltage levels in constant or varying relation to each other.

It is also possible for two or more charge neutralizing regions to have different "strengths", i.e., to have different potentials. The ionization regions 105 and the charge reduction regions 108 may be alternately arranged. In the flow path, there may be two or more charge neutralization regions 108 after one ionization region 105. A series of two or more ionization regions 105 may be provided before one or more charge reduction or neutralization regions 108. By placing two successive charge neutralizing devices 108 spaced apart from each other, there may be a gap between successive charge reduction or neutralization regions 108 (see, e.g., fig. 9). There may be a gap between two consecutive ionization regions (see fig. 8).

Fig. 4 to 9 schematically depict different arrangements of the charge reduction region 108 and the one or more ionization regions 105, not necessarily drawn to scale. These are provided as examples only and are not exhaustive of all possibilities for the arrangement. For simplicity, in these figures, only the different regions are labeled, and other components in the system, such as electrodes, optional sensors or lamps, fans, etc., are not shown.

Thus, the described system 100 utilizes different ion adsorption processes to produce charged aerosols and/or particles, followed by charge reduction to effect a change in potential in the charged aerosols and/or particles, or neutralization of the aerosols and/or particles, and in doing so, a temporary flow of electrical current to remove, inactivate, or eliminate infectious agents. The described system 100 potentially further includes other filtering (e.g., by chemical bombardment or immersion) or disinfection functions.

For example, the following parameters may be used in the implementation of the described system. It is to be understood that the exact parameters may vary without departing from the spirit of the invention. Such changes may depend on a variety of factors, such as the environment in which the system is used (e.g., clinical, home, laboratory, commercial), the size of the room or room in which the air is being purified, the desired filtration rate, and so forth.

In one laboratory experiment, an input of 18 volts was provided to a transformer to produce a voltage of-6.5 kV (kilovolts) at the ionizing electrode at an air flow rate of 50 cubic meters per hour.

Preferably, the ionizing electrode will be charged to produce negative ions at a concentration of at least 1000 ions per cubic centimeter. During the test, a concentration of 1900 ten thousand negative ions per cubic centimeter has been measured. It is contemplated that a concentration of, for example, 1 million to 1 million, or preferably 1 million to 3000 ten thousand ions per cubic centimeter is feasible as the working ion concentration range. However, the disclosed method does not depend on a particular concentration of ions, as long as there is a sufficient concentration to charge a sufficient amount of aerosol and/or airborne particles for the purpose of gas stream purification.

An example of the charge reduction stage 107 used during prototype testing is a wire mesh made of stainless steel with a mesh design of 50 holes per square centimeter. However, as noted above, other types of devices may be used for the charge reduction phase 107.

Fig. 10 schematically depicts the system 100 and the control and power supply means required to power the system 100. The depicted system 100 is the system shown in fig. 2, but it should be understood that different embodiments of the system 100 may alternatively be included. The control and power supply means may be located in the controller or in a separate device, the exact configuration may be determined by space or design requirements. Here, various modules are shown in block 120, block 120 conceptually representing the control and power supply means. The dashed line drawing indicates that the various modules contained therein need not be provided in the same physical device.

The control and power supply device 120 includes a control module 121, and the control module 121 may include a processor or microprocessor to control the operation of the system 100. A user input/output (I/O) device 126 may be provided, with the user input/output (I/O) device 126 being collocated with the control module 121 or connected with the user input/output (I/O) device 126 using a wired or wireless connection to allow a user to monitor or control the operation of the system 100. The I/O device may be one unit or may be separate input and output units. The control and power supply device 120 may also include one or more communication modules 127 to enable short range (e.g., short range)

) Short range or long range (e.g., 3G, 4G, 5G, WiFi, etc.). If included, the communication module 127 enables the control and power supply device 120 to send data transmissions to the mobile unit 128 and receive data transmissions from the mobile unit 128. The mobile unit 128 may be a remote control or a mobile device such as a smart device configured to communicate with the control and power supply apparatus 120 using compatible communication capabilities. This would allow the user to control operations such as turning on or off the cell or specific components within the cell (e.g., decorative lights, electrodes or reduction levels within a specific ionization or neutralization zone, airflow), checking any metrics monitored, adjusting operating settings (e.g., voltage level, color of any lights included, airflow rate, etc.).

In order to provide power for the operation of the system unit and the various components therein, as well as for the operation of the control unit 120, the control and power supply means 120 will further comprise power supply means. The power supply apparatus may include a mains power module 122 to receive mains power, which is then converted to Direct Current (DC) power. Alternating Current (AC) mains power may be supplied through a USB (universal serial bus) connector and then converted to DC. A DC power module 123 may be present to receive DC power, such as from a battery. A direct DC power supply or a converted DC power supply would be used to provide voltage to ionizing electrodes 104,109. Block 124 represents a negative voltage module that will provide the required voltage or voltages to provide to the

electrodes

104, 109. The negative module 124 may convert the input power to a different voltage suitable for providing to the

ionizing electrode

104, 109 and may provide to the charge reduction phase 107 if the devices of the charge reduction phase 107 are to be charged to a negative potential. The negative module 124 may also include desired circuitry, such as an inverter that converts incoming AC power to DC power of a desired polarity. Depending on the embodiment, it may alternatively or additionally be possible to have a positive voltage module 125, the positive voltage module 125 being configured to supply a positive potential to the ionizing electrode (if positive ions are used to charge the aerosol and/or particles), and to supply a positive potential (if any) to the one or more charge reduction stages 107. Both the positive voltage module 124 and the negative voltage module 125 may be provided for greater operational or control flexibility.

In the above embodiments, the ionizing electrodes will be configured to provide sufficient electrical discharge to perform the described functions on the gas stream to be disinfected. For example, to generate negative ions smoothly, in some embodiments, ionizing electrode 104 (and optional additional electrode 109) may have multiple tips on the negative electrode that are configured to provide one point or two or more points at which charge density and electric field strength are concentrated. Generally, a greater tip curvature will result in a higher degree of concentration. That is, it is desirable to have sharper sharp locations (typically, large tip curvatures, higher degrees of charge density, high electric field strengths). For example, the first negative electrode 105 and the second negative electrode 106 may be needle-shaped, and the tip corresponds to the needle shape. The design may of course also be constrained by physical limitations imposed by the housing 101 or mounting location. However, the specific design of the electrodes need not be limited. For example, for aesthetic reasons, the electrodes may be configured to form a particular design, such as a star or other shape.

Prototype testing was performed in separate experiments using SARS-CoV-2 aerosol and Getah virus aerosol, respectively, as described in more detail below. These experiments were designed to detect the presence of infectious virus in the medium when the test system was closed and compare the results with those when the test system was open.

Experimental setup, methods and results for systematic testing using SARS-CoV-2 Aerosol

FIG. 11(a) is a picture of a system set up for testing in the laboratory to determine the effectiveness of the described device in disinfecting an air stream containing an airborne SARS-CoV-2 virus aerosol. The experimental set-up 200 includes a sealed plexiglass container 202, the plexiglass container 202 being located within a biosafety cabinet (BSC) 204. The test unit 201 is placed in a sealed box 202. Inside the sealed box 202, a nebulizer 206 for generating infectious aerosol and a tank for introducing and removing a 96-well plate 208 containing medium and Vero E6 cells were placed. An electronic control external to the case allows the atomizer, fan and negative electrode in the test system to be turned on and off. Fig. 11(b) shows a more detailed picture of the nebulizer, where the virus solution container 210 and the vent 212 for the incoming air can be seen.

As described in more detail below, tests were performed to measure the concentration of virus in the medium when the test system was turned off, and this result was compared to the result obtained when the test system was turned on.

Negative electrode off (no ionization) and no charge reduction-8 milliliters (ml) of SARS-CoV-2 (containing about 10) loaded into the nebulizer in growth medium⁶log₁₀CCID₅₀Virus/ml). For the growth medium, RPMI1640 supplemented with 2% FCS (fetal calf serum) and buffered with 10mM HEPES ((4- (2-hydroxyethyl) -1-piperazineethanesulfonic acid) was used, the box was sealed and the nebulizer was run for 3 minutes while the mediair unit fan was on (power supply 3.5 volts), then the nebulizer was closed and the fan was run for 2 minutes, then the lid on the 96-well plate was uncovered and the fan was run for 15 minutes, then the fan was closed and the aerosol was discharged by opening the exhaust pump and by opening the vent hole above the nebulizer for 2 minutes, the 96-well plate in the box was replaced by the slot in the box while the pump maintained negative pressure and the vent hole above the nebulizer was closed, the 96-well plate was recovered, a new sterile lid was placed on the plate, the plate was sprayed with 80% ethanol, then the plate was transferred to the incubator in the sealed box, cultures were incubated for 6 days to evaluate the viral cytopathic effect (CPE) indicative of the presence of infectious virus.

The negative electrode is on (ionization on) and charge reduction is on. The above procedure was repeated with the negative electrode open (18 volts), each duration including 2 minutes of nebulization, 2 minutes of capping the medium well, 15 minutes of removing the cap from the medium well, and 2 minutes of degassing.

As a result: in the prototype test described above, the experiment in the aforementioned "negative electrode on" configuration showed an infectious aerosol removal rate of 100% compared to the amount of viral material detected in the growth medium wells after the "negative electrode off" experiment. Fig. 12(a) shows the switching order of the respective components in the system shown in the photograph in fig. 11.

When the Negative Electrode (NE) was turned off, infectious aerosol was captured in 85 of the 96 wells, and the wells of the 96 well plate contained Vero E6 cells containing 200 microliters of medium supplemented with 5% FCS (fetal calf serum). A decrease in blue/violet crystal violet staining intensity in the wells indicates a viral cytopathic effect-see figure 12 (b). When the Negative Electrode (NE) was turned on, 0 of the 96 wells showed CPE, indicating no infectious aerosol was detected in the wells, and in this setting the device removed 100% of the infectious aerosol-see fig. 12 (c).

In the prototype test described above, the experiment in the aforementioned "negative electrode on" configuration showed an infectious aerosol removal rate of 100% compared to the amount of viral material detected in the growth medium wells after the "negative electrode off" experiment. Fig. 12(a) shows the switching order of the respective components in the system shown in the photograph in fig. 11.

Experimental setup, method and results for system testing using Getah virus aerosol setup:

setting: figure 13 is a picture of a system set up for testing in the laboratory to determine the effectiveness of the described device in disinfecting a gas stream containing a viral aerosol of Getah virus.

The laboratory apparatus 300 includes a sealable plexiglass container 302, the plexiglass container 302 being located within a biosafety cabinet 304. Inside the box 302, a test unit 301 of the proposed system is placed. Also located in the plexiglas box 302 are a nebulizer 306 for producing infectious aerosol and a wet surface aerosol collector 308, which is a 96-well plate. The 96-well plate contained 200 μ l of RPMI1640 medium with 5% FCS in each well and 10,000 Vero E6 cells seeded the day before.

The procedure for testing the results in the wet collector is described in the following experimental procedures.

The negative electrode is off (no ionization) and there is no charge reduction. The nebulizer was loaded with 2ml GETV in RPMI1640 supplemented with 2% FCS and 100ul GETV 10 in RPMI1640^8.2TCID₅₀. The tank was sealed and the nebulizer was allowed to run for 2 minutes while the fan (voltage 3.5 volts) of the mediair unit (i.e. test unit) was turned on. The atomizer was then turned off and the fan was run for an additional 2 minutes. The cover of the wet collector was then uncovered and the fan was run for an additional 10 minutes. The fan was turned off, then the uv was turned on and the aerosol was discharged into vacuum through the port for 2 minutes. The BCS chamber was opened, the 96-well plate was recovered, sprayed with 80% ethanol, and the plate was cultured for 6 days to evaluate viral cytopathic effect (CPE).

The negative electrode is on (ionization on) and charge reduction is on. The above procedure was repeated, and during 2 minutes of atomization, the negative electrode was turned on. The atomizer was then turned off, the fan of the test unit was turned on with the lid on the wet collector for 2 minutes, the fan of the test unit was turned on with the lid removed from the wet collector for 10 minutes, and then vented for 2 minutes (at 18 volts). At the end of the experiment, the lid was closed and the plates were incubated for 6 days to assess CPE.

As a result: prototype testing showed significant bactericidal and/or scavenging activity when the negative electrode was turned on. The results of wet collection showed that 90 wells had CPE, indicating that infectious virus was present in the case of negative electrode shut-down during operation (90 light wells detected in fig. 14 a). After running with the negative electrode on, no CPE was detected in any of the wells (all wells are dark in fig. 14 b), indicating the absence of infectious virus.

Variations and modifications of the previously described parts may be made without departing from the spirit or scope of the present disclosure.

For example, if the system 100 is installed into or integrated with a system in which airflow is present (e.g., an air circulation, filtration, or conditioning system), an air purification or disinfection system may be disposed in the air path to act on the air drawn in by the system, and thus a separate fan or other device may not be required to achieve negative pressure. For example, fig. 15 depicts a version of the system 100 shown in fig. 1 installed in the airflow path 152 of an existing system 150, the existing system 150 including its own airflow generating device 154 to effect airflow.

As shown, the system 100 may be installed in a duct 156 within an existing system such that the housing 101 provides an open inlet to receive an incoming airflow, and an open outlet 103 through which the existing airflow exits the housing 101. Alternatively, the system may provide a duct portion or a structural portion through its housing 101 in which air flows. Alternatively, one or more of the conduit portions of the existing system 150 may be configured to serve as the housing 101 of the system in which the system components are disposed to perform the desired function.

The system 100 may be attached to or integrated with a wearable device, such as PPE, to handle airflow and provide clean air for the wearer to breathe. In a wearable embodiment, the system 100 would need to have a built-in fan to drive the airflow in the PPE, or draw in ambient air to treat it, or both. The system 100 would also desirably include a battery to power the components.

As shown by the experiments, the system described herein has been shown to remove, inactivate or eliminate 100% of infectious aerosols in prototype testing. This is in contrast to the prior art, where HEPA (high efficiency particulate air) filters are included in existing devices to capture infectious aerosols. The system 100 is much less expensive to manufacture, requires less power to operate, and is lightweight compared to systems that require HEPA filters, because the system 100 does not require as much power (and therefore weight) as a fan unit, and does not require the same number of batteries to operate. Thus, the system 100 provides significant technical advantages over prior devices that utilize HEPA filters. This makes it possible for the system to be provided in a wearable device (e.g., PPE) or a portable device.

It should be understood that other variations of the system 100 are possible to be provided in an existing airflow path of another system for integration in the other system. This allows the air purification or decontamination system 100 to be retrofitted to existing building air circulation or air handling systems.

In the above embodiments, the system may also be provided with one or more air filtration devices to provide air filtration functionality.

In the above embodiments, in the air ionization region, the aerosols and/or suspended particles are charged by negative charges-e.g. by electrons discharged from the electrodes-and current is induced to flow from at least some of the charged aerosols and/or particles to the conductive means of the charge reduction stage 107, which provides for reduction or neutralization of the negative charges. However, in alternative embodiments, by applying a positive potential to the electrodes, the aerosol and/or particles may be charged by a positive charge, and the charge reduction or neutralization device 107 will be configured to reduce or neutralize the positive charge.

In the above embodiments, the electrodes may be formed of different materials, such as gold, silver, platinum, or carbon fiber, as long as the electrodes perform the desired functions. They may be metallic or non-metallic materials plated with gold, silver, platinum or copper. They may also take various shapes, such as needles, circles, or may have an attractive design that enhances the aesthetics of the system, particularly where the electrodes are visible.

Other components may also be provided in the housing to create additional functionality, such as a non-UV lamp that provides visible light through the housing so that the unit can be used as a lamp or lighting device, or to enhance the aesthetics of the unit.

In embodiments where the system includes an air pressure generator that generates an air flow, the air pressure may be provided by a fan or air pump to generate a positive pressure, or may be provided by a vacuum extractor to generate a negative air pressure.

In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

Claims

1. An air sanitizer system comprising:

an air inlet for receiving an air flow into the air sanitizer system and an air outlet; the air outlet is for exhausting the airflow from the air sanitizer system with a conduit between the air inlet and the air outlet;

comprising, arranged in the duct in the direction of the air flow:

an ioniser in which, in use, a first air ionisation region is created, aerosol and/or suspended particles in incoming air being charged; and

a charge reduction stage for creating a first charge reduction zone, wherein charged aerosols and/or particles are attracted to the charge reduction stage as they pass through the stage and are at least partially discharged upon contact with the stage, charging and subsequent discharge removing, inactivating or eliminating at least some aerosols and/or suspended particles.

2. An air disinfecting system as claimed in claim 1, wherein the ioniser comprises a plurality of electrodes distributed within the first ionisation region and which, in use, are charged to generate negative ions to charge aerosols and/or suspended particles in air entering through the first air ionisation region.

3. The air sanitizer system of claim 2, wherein the electrode is charged to provide a corona discharge.

4. An air decontamination system as claimed in claim 3, wherein the electrodes are plated with silver, gold, copper or platinum.

5. An air decontamination system according to any one of claims 2 to 4, wherein adjacent electrodes are separated by a distance of at least 1.5 cm.

6. An air disinfecting system as claimed in any preceding claim, comprising one or more further ionisation regions.

7. The air sanitizer system of claim 6, wherein at least two of the two or more ionization regions are configured to charge particles in the incoming air to different potentials.

8. An air disinfecting system as claimed in claim 7, wherein the ionisation region closest to the inlet is configured such that the aerosols and/or suspended particles in the incoming air are charged to provide a minimum level of ionisation compared to other ionisation regions.

9. An air disinfecting system as claimed in any preceding claim, further comprising one or more further charge reduction stages.

10. An air disinfecting system as claimed in claim 9, when dependent on any one of claims 6 to 8, at least two of the charge-reduction phases within the duct and two of the ionisation regions are arranged in an alternating manner.

11. An air decontamination system as claimed in any preceding claim, wherein a charge reduction device is provided in the first charge reduction phase, the charge reduction device being connected to ground or a power supply.

12. The air sanitizer system of claim 11, wherein the charge reduction device comprises a structure having a textured surface.

13. An air decontamination system as claimed in claim 11 or 12, wherein the material of the charge reduction device comprises an anti-bacterial or anti-bacterial additive.

14. An air disinfecting system as claimed in any one of claims 1 to 10, comprising at least two charge reducing means arranged in series in the duct, the two charge reducing means having different electrical potentials.

15. An air disinfecting system as claimed in any preceding claim, further comprising at least one outlet ionisation region disposed adjacent the outlet.

16. An air disinfecting system as claimed in any preceding claim, in which one or more light sources are mounted.

17. An air disinfecting system as claimed in any preceding claim, comprising air pressure generating means for driving the air flow.

18. The air sanitizer system of any one of claims 1 to 17 included in a wearable or portable device.

19. The air disinfecting system of claim 18, wherein the wearable device is a personal protective equipment.

20. An air sterilizer system according to any preceding claim, which is retrofitted into an existing building, transport or vehicle air circulation system.

21. A personal protective device comprising an air disinfecting system as claimed in any one of claims 1 to 19.

22. An air purification method comprising:

generating air pressure to draw an air flow through the flow path;

providing positive or negative ions in the flow path to charge aerosol, suspended particles, or both in the flow path; and

changing the potential of at least some of the charged aerosol, the suspended particles, or both.

23. An air purification method as claimed in claim 22, comprising providing a device in the flow path, the device having a surface connected to electrical ground, or to which a potential is applied, the potential being set at a level to cause the change in potential of at least some of the charged aerosols and/or suspended particles, the device being adapted to cause the airflow to pass therethrough.

24. An air purification method as claimed in claim 22 or 23, comprising further charging the aerosol and/or particles after said change in potential of at least some of the charged particles.