KR20220099702A - Air cleaning device using atmospheric-pressure plasma - Google Patents

Abstract

The present invention relates to an air purifier using atmospheric pressure plasma. In detail, the air purifier sterilizes and purifies pathogens, bacteria, viruses, or mold poisons while removing ozone. More specifically, the air purifier comprises: an air fan (10) sucking air; a plasma generator (20) having a structure in which a plurality of stacked electrode panels, where dielectrics (23) are installed on both inner walls between a discharge electrode (21) and a grounding electrode (22), are stacked; and an ozone filter (30) enabling a catalyst decomposing ozone to be supported. The air purifier has a simple structure to be easily installed and minimized and has rapid sterilization time to perform effective treatment.

Description

Air cleaning device using atmospheric-pressure plasma

The present invention relates to an air purifying device using atmospheric plasma, and more particularly, to an air purifying device capable of sterilizing and purifying pathogens, bacteria, viruses, or fungal poisons and simultaneously removing ozone using dielectric barrier discharge. In particular, it is an air purifier using plasma targeting new coronavirus and new influenza virus.

Recently, mass infection of infectious diseases caused by the new coronavirus is taking place on a global scale, and it is becoming a big social problem. In particular, Corona virus-19 (COVID-19), a virus that causes respiratory diseases, has a very high infectious disease. In particular, in a humid indoor space, the new coronavirus floating in the air is difficult to dry and maintains its infectivity for several 10 minutes. There is also the opinion that it can survive more than 3 hours in aerosol state.

In separate spaces such as general homes, offices, hospitals, restaurants, and bars, the risk of infection increases because the new coronavirus with infectious power is highly likely to be floating as an aerosol. In order to protect the body from the novel coronavirus floating in the air, it is necessary to periodically and completely ventilate the air existing in an enclosed space. When ventilation is not possible, it is required to purify or sterilize the air in the room. In particular, in hospitals or elderly care facilities, air conditioning equipment having a sterilization function is required.

In general, various methods other than the plasma method are adopted in the air purification apparatus, but since the required time (exposure time) for sterilization is long, the manufacturing cost is high, such as an increase in power consumption, and there is little practical value.

Plasma reacts with air to generate various active species including ozone, OH radicals, and negative ions. Among these active species, ozone exhibits a sterilizing and disinfecting action and also decomposes chemicals.

In particular, in the sterilization method using ozone generated during plasma discharge, ozone itself is very unstable, has a strong oxidizing power, and is a highly reactive substance. In this case, the sterilization effect is relatively weak, and there is a disadvantage that at least an exposure time of about 55 minutes is required to sterilize or inactivate the corona virus.

Therefore, there is a need for an air purifier that can reduce the manufacturing cost with a simple process as well as safely and effectively treating the new coronavirus while shortening the sterilization time.

Domestic Registered Patent No. 10-0779841 (Registration Date 2007.11.20.) Japanese Patent Application Laid-Open No. 2018-110648 (published on July 19, 2018) Japanese Patent Application Laid-Open No. 2020-163232 (published on Oct. 8, 2020) Domestic Registered Patent No. 10-2005618 (Registration Date 2019.07.24.) Domestic Registered Patent No. 10-2138300 (Registration Date 2020.07.21.)

SUMMARY OF THE INVENTION An object of the present invention is to provide an air cleaning device that can reduce manufacturing cost and is easy to install by using atmospheric pressure plasma adopting a plurality of dielectric barrier structures.

It also aims to provide a combination of devices that can remove ozone generated during plasma discharge and completely sterilize new coronaviruses with high infectious power.

In order to solve the above problem, a structure in which a plurality of electrode panels in which an air fan 10 for sucking contaminated air and a dielectric 23 are installed on both inner walls between the discharge electrode 21 and the ground electrode 22 is laminated. There is provided an air purifier comprising an excitation plasma generator (20) and an ozone filter (30) carrying a catalyst for decomposing ozone.

Dielectric barrier discharge (DBD) occurs as the contaminated air is sucked and passes through the gap between the electrode panels of the plasma generator 20, and bacteria contained in the air are removed by active species generated by the plasma discharge. It is sterilized and harmful substances such as fine dust are decomposed. Among the active species, ozone is included, and although ozone has an excellent sterilizing power, its concentration should be limited to a certain level or less because it adversely affects the human respiratory system. Therefore, it is necessary to separately provide the ozone filter 30 on which the catalyst is supported as a means for removing ozone.

In the plasma generator, the distance S between the discharge electrode 21 and the ground electrode 22 is 1 mm or less.

In addition, the plasma generator is characterized in that it is driven using AC power or DC pulse power. The frequency of the power is characterized in that it is driven using a power supply of 20 kHz or higher.

In addition, in the electrode panel of the plasma generator, the material of the discharge electrode is tungsten, and the material of the dielectric is aluminum oxide.

In addition, the catalyst supported on the ozone filter provides an air cleaning device, characterized in that manganese dioxide.

According to the present invention, since the atmospheric pressure plasma apparatus does not require expensive vacuum equipment, it is economical and can be processed in an inline form, thereby maximizing productivity.

In particular, the dielectric barrier operates in very large non-equilibrium conditions at atmospheric pressure, can perform high-power discharge, and does not require a complex pulsed power supply, so it can safely and effectively treat new coronaviruses in a short time.

In addition, since some bacteria or viruses that are not sterilized in the plasma generator can be completely removed by the mixing action with the ozone filter, a separate heating or cooling step is not required, so that the device can be miniaturized.

1 is a schematic cross-sectional view of an air cleaning apparatus using atmospheric pressure plasma according to the present invention.
2 is a cross-sectional view of an air cleaning device according to another embodiment of the present invention.
3 is a cross-sectional view of an air cleaning device according to another embodiment of the present invention.

Hereinafter, with reference to the drawings, FIG. 1 is an air cleaning device using atmospheric plasma, and includes an air fan 10 , a plasma generator 20 , and an ozone filter 30 . The components are sequentially installed in a housing made of stainless steel (SUS316).

The plasma reactor is driven using a DC pulse power supply (not shown) and has a structure in which a plurality of electrode panels with dielectrics 23 installed on both inner walls between the discharge electrode 21 and the ground electrode 22 are stacked, and has a rectangular parallelepiped shape. . The rectangular plate-shaped electrode panel is disposed in the housing in parallel to the air passage direction and has a gap (S, in this embodiment, a gap of 0.5 mm) with each electrode. Wires (not shown) of each electrode panel are alternately electrically connected.

The DBD structure consists of two parallel metal electrodes. The surfaces of the two electrodes bond at least one dielectric to directly control arcing. To ensure stable plasma operation, the gap separating the electrodes is limited to a few millimeters, and plasma gas flows through this gap. In the dielectric barrier discharge, there is no spark that causes local waves or noise, but depending on the operating voltage and frequency, the discharge is in the form of a filament or a glow. Filamental discharges are created by microdischarges or streamers that develop on the surface of the dielectric layer.

Since it is composed of two electrodes, it is structurally simple and has ease of installation on the object. In addition, since the actuator can be miniaturized, it can be easily applied to flow control in the boundary layer. In addition, compared to other devices, power consumption is low and real-time control is possible through fast response characteristics.

Here, as a material for forming the discharge electrode, tungsten (W), molybdenum (Mo), ruthenium oxide (RuO2), silver (Ag), copper (Cu), platinum (Pt), etc. may be used, and tungsten is most preferable. . The thickness and width of the electrode can be designed to optimize the plasma according to the intended use, and in the present invention, the width (W) can be adjusted from 70 mm to 300 mm according to the residence period.

In the conventional atmospheric dielectric barrier discharge plasma apparatus, since the distance S between the electrodes is set to be approximately 1 mm or more, the applied voltage is high, heat is generated, and power consumption is increased. Therefore, in the present invention, it is necessary to design the gap to be 1 mm or less, preferably 0.5 mm, and the thickness of the dielectric thin film coated on the electrode surface should not exceed 0.1 mm if possible, and it is preferable to be manufactured by a sol-gel method. do.

In particular, since the voltage or power for generating the plasma strongly depends on the thickness of the dielectric, the thinner the film thickness, the less power consumption for generating the plasma. In addition, since the electric field strength (E) is the applied voltage (V) / the distance between the electrodes (S), when the distance between the electrodes is short, the electric field strength increases and plasma is easily generated. However, if the distance is too close, the probability of collision with air is low, so it is not ionized and discharge may be difficult, so the voltage should be increased as necessary. That is, the most appropriate distance, pressure, and voltage are required for discharge.

In addition, the plasma generator is preferably driven using an AC power supply or a DC pulse power supply. In this way, since current flows through the discharge electrode at regular intervals, the power consumption and the amount of heat generated by the plasma generator can be reduced.

The frequency of the power applied to the electrode preferably has a frequency of 10 to 100 kHz, and the output voltage is preferably in the range of 10V to 2kV. In general, when the gap between the electrodes is 1mm, 20kHz frequency and power of 3~4kV may be supplied.

In addition, as a dielectric material forming material, aluminum oxide (Al2O3), aluminum nitride (AlN), yttrium oxide (Y2O3), magnesium oxide (MgO), titanium oxide (TiO2), silicon oxide (SiO2), neodymium, ferrite, etc., or mixtures thereof can be In particular, when the material of the discharge electrode is tungsten and the material of the dielectric is aluminum oxide, the firing temperature is lower than that of aluminum nitride or the like.

The atmospheric pressure plasma reactor is used to remove contaminants such as new corona virus that is introduced from an air fan and passes through the gap S. In this case, when a pulse voltage is applied from a DC pulse power supply to an adjacent electrode panel, dielectric barrier discharge is generated and plasma is generated in the discharge electrode. Therefore, viruses and the like contained in the air passing through are inactivated.

However, ozone is included among the active species produced by plasma discharge, which has excellent sterilization power, but adversely affects the human respiratory tract, etc. shall.

Accordingly, an ozone filter constituting the air purifier is disposed on the downstream side of the plasma reactor and is provided with a catalyst carrier. This serves to decompose ozone generated when dielectric barrier discharge is performed in the plasma reactor, and is preferably arranged in a honeycomb structure in parallel to the air passage direction in the housing. In this embodiment, the material of the catalyst carrier is preferably cordierite, and any one of metals such as other ceramics such as aluminum oxide and aluminum nitride and stainless steel (SUS316) may be selected.

The catalyst for decomposing ozone is used by being supported on a catalyst carrier. Here, as a material of the catalyst, manganese dioxide (MnO2), nickel oxide (NiO), or the like may be selected. In particular, when the catalyst is manganese dioxide, ozone can certainly be decomposed by the catalyst.

When a dielectric barrier discharge having a stacked structure as in the present invention is used, active species including ozone are generated, bacteria are sterilized by contact of the generated active species, and viruses are rapidly inactivated. In addition, when ozone passes through the ozone filter of the present invention, active oxygen is generated when ozone is decomposed by the catalyst. By contact with this active oxygen, some bacteria that were not sterilized by the plasma reactor can be sterilized, and viruses that have not been inactivated by the plasma reactor can be further inactivated.

That is, by the mixing action of the plasma generator and the ozone filler, it is possible to remove quickly and reliably than conventional devices through sterilization of bacteria or inactivation of viruses in polluted air. In addition, such an air purifier has an advantage in that it does not require a separate heating or cooling step of air for rapid and complete sterilization of bacteria or inactivation of viruses.

In addition, since both the plasma generator and the ozone filter are used to sterilize bacteria or inactivate viruses, even if the amount of contaminated air is increased, it is not necessary to apply a high voltage to the gap between the electrode panels on which the dielectric is installed. increase in power consumption is suppressed. In addition, since the plasma generator does not need to be enlarged in order to enable application of a high voltage to the gap between the electrode panels, it is possible to reduce the size of the air purifier.

Plasma chemical reactions and plasma physical reactions such as positive ions, negative ions, ultraviolet rays, active oxygen (O radical, OH radical, etc.), active nitrogen (N radical, NO radical, etc.), ozone, etc. By, most can be killed or inactivated. However, since the residence time in the air purifier is important, it is desirable to increase the residence time in order to more reliably inactivate the virus to be sterilized, but also consider the amount of air flow, the flow rate, and the width of the electrode panel.

Therefore, if necessary, calculate the average flow rate of the incoming air and adjust the number of electrode panels and the width (W) of the electrodes for the optimal residence time for perfect sterilization effect, or the distance (L) between the plasma generator and the ozone filter It can be even more effective if it is dynamically controlled.

2 is a case in which the distance L between the plasma generator 20 and the ozone filter 30 is narrowed close to an air cleaning device according to another embodiment of the present invention.

3 is a case in which a plurality of electrode panels of different widths (W) are installed, which relates to an air cleaning device according to another embodiment.

10 air fan
20 Plasma Generator
21 ground electrode
22 discharge electrode
23 dielectric
30 ozone filter

Claims (6)

an air fan (10) for sucking the polluted air;
A plasma generator 20 having a structure in which a plurality of electrode panels in which dielectrics 23 are installed are stacked on both inner walls between the discharge electrode 21 and the ground electrode 22;
An air purifier comprising an ozone filter (30) carrying a catalyst for decomposing ozone. The air purifier according to claim 1, wherein the distance (S) between the discharge electrode (21) and the ground electrode (22) is 1 mm or less. The air cleaning device according to claim 1, wherein the plasma generator (20) is driven using an AC power supply or a DC pulse power supply. The air cleaning device according to claim 1, wherein the plasma generator (20) is driven using a power source having a frequency of 20 kHz or higher. The air purifier according to claim 1, characterized in that the material of the discharge electrode (22) is tungsten, and the material of the dielectric (23) is aluminum oxide. The air cleaning device according to claim 1, wherein the catalyst supported on the ozone filter (30) is manganese dioxide.

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