Plasma air purification apparatus

Abstract

The present invention relates to an apparatus for purifying indoor air using plasma and, in particular, to an atmospheric pressure plasma air purification apparatus which has a function of, by generating plasma in an atmospheric pressure state, simultaneously removing microorganisms, such as bacteria and viruses, volatile organic compounds (VOCs), and various harmful substances such as odors, which are contained in the air. The plasma air purification apparatus according to an embodiment of the present invention comprises: a plasma discharge module which generates plasma to remove microorganisms, such as bacteria and viruses, and various harmful substances, which are contained in sucked air; a catalyst filter unit which removes residual ozone (O3) remaining after a chemical reaction by plasma; an ultraviolet (UV) irradiation unit which rapidly accelerates an ozone (O3) decomposition reaction by the catalyst filter unit; an ozone sensor unit which detects the concentration of residual ozone (O3) generated by plasma; a power supply unit which supplies power to the plasma discharge module; and a control unit which controls power supply from the power supply unit, wherein the control unit alternately controls at least two plasma discharge modules to be sequentially and continuously supplied with power.

Description

Plasma air purifier

[0001] The present invention relates to a plasma air purification device. In particular, the present invention relates to a plasma air purification device equipped with an ozone (O3) decomposition catalyst.

[0002] More specifically, the present invention relates to a method for manufacturing a device that simultaneously removes microorganisms and harmful substances contained in the air by generating low-temperature plasma under atmospheric pressure, and more specifically, to kill bacteria, viruses, etc. and remove harmful substances to the human body such as ammonia, hydrogen sulfide, formaldehyde, etc. by utilizing the high sterilizing power of ionized active species such as hydroxyl radicals (OH Radicals) and active oxygen generated by plasma discharge under atmospheric pressure.

[0003] The present invention relates to a method for manufacturing an atmospheric pressure plasma air purification device having a structure and control method capable of preventing a decrease in plasma performance caused by side effects resulting from continuous application of strong energy to a plasma discharge electrode by continuous driving.

[0004] In addition, the present invention relates to a method for manufacturing a catalytic filter and promoting a catalytic reaction necessary to quickly decompose ozone (O3) generated during plasma discharge in atmospheric air and lower its concentration below the environmental standard to discharge purified air by discharging it within an air purification device, as this can be harmful to the human body.

[0005]

[0006] Air contaminated with various pathogenic bacteria, viruses, volatile organic compounds (VOCs), odors, fine dust, and other harmful substances, including COVID-19, is recognized as a serious social problem that threatens people's daily lives. To improve these problems, the use of air purifier products that help improve the air quality in our living environment is on the rise.

[0007] Air purifiers using a dust collection filter are commonly used to collect floating dust contained in the air to maintain the cleanliness of indoor air, but the effectiveness of removing pathogens such as various bacteria, viruses, and mold is limited due to the limitations of the built-in filter performance.

[0008] In contrast, an air purifier using plasma applies high energy to molecules such as oxygen and water vapor in the air, which are separated into positive and negative ions, and the hydroxyl radicals (OH Radicals) and active oxygen generated at this time are hydrogen ions (H), which are the main components of bacteria and viruses. + ) can be combined with the cell membrane to destroy it, killing it and reducing it back to water (H2O) and oxygen (O2), resulting in an environmentally friendly sterilizing effect.

[0009] In addition to its ability to remove pathogenic microorganisms, it is known to be able to help human life by removing pollutants such as volatile organic compounds (VOCs), bad odors, and fine dust, as it has the ability to decompose various harmful substances.

[0010] In order to obtain good results by applying plasma to an air purifier in the air, plasma must be generated with an output suitable for the device's usage environment. However, since strong energy is continuously applied to the plasma discharge electrode, the problem of performance degradation due to discharge electrode burnout occurs, and the side effect of generating ozone (O3), a gas harmful to the human body, also occurs.

[0011] Due to these problems, the plasma discharge output had to be weakly limited, making it difficult to obtain a good air purification effect. Some products use activated carbon adsorbents to remove the ozone (O3) generated at this time, but the ozone (O3) removal effect has been confirmed to be limited.

[0012] Recently, various plasma sterilization and deodorization devices have been disclosed as a way to solve these problems, such as the "Sterilization and Deodorization System Using Ozone and Low-Temperature Plasma Photocatalyst" in Korean Patent No. 10-2427415. Although there have been efforts to increase the sterilization and deodorization effect by using ultraviolet (UV) rays and photocatalysts in addition to plasma, there is currently no clear method for effectively removing ozone (O3), a harmful gas generated internally by plasma discharge.

[0013]

[0014] The present invention aims to provide an air purifying device with improved lifespan and air purifying performance in order to solve the above-described problems.

[0015] In addition, the present invention aims to provide a method for manufacturing an air purifying device at a lower cost.

[0016]

[0017] In order to achieve the above-described object, the air purifying device of the present invention comprises a plasma reaction unit equipped with at least two plasma discharge modules that generate plasma to purify air contaminated with harmful substances such as various pathogenic bacteria, viruses, odors, fine dust, etc. contained in the air, a catalytic filter unit connected thereto and for removing ozone (O3) inside, an ultraviolet (UV) irradiation unit for rapidly promoting an ozone (O3) decomposition reaction of the catalytic filter unit, a power supply unit for supplying power to the plasma discharge modules, and a control unit for controlling the power supply of the power supply unit, wherein the control unit is characterized in that it controls the at least two plasma discharge modules to be supplied with power in a regular cycle and sequentially, but to have continuity overall.

[0018] Here, the plasma discharge module is generally composed of two or more even-numbered modules and can be symmetrically installed in the front, back, left and right directions based on the center of the plasma reaction section.

[0019] Meanwhile, the catalyst of the catalyst filter section, which has the function of removing residual ozone (O3) remaining after a chemical reaction in the plasma reaction section, is in the form of a pellet or ball having a diameter of 5 mm or less containing 72 to 84 mol% of manganese dioxide (MnO₂) and 16 to 28 mol% of copper oxide (CuO), and titanium dioxide (TiO₂) particles having a diameter of 100 nm or less are evenly applied or coated on the surface of the catalyst at 50 to 80%, and is provided in the form of a flat honeycomb filter having a gas-permeable structure with a built-in compound catalyst.

[0020] In addition, in order to more quickly promote the ozone (O3) decomposition reaction of the catalyst filter section, ultraviolet (UV) is irradiated onto the catalyst, and this ultraviolet (UV) generating device is characterized by having a function of increasing the activity of the catalytic reaction and promoting the ozone (O3) decomposition reaction by irradiating ultraviolet (UV) using at least four semiconductor LEDs having a light source wavelength of 250 nm to 400 nm and an ultraviolet (UV) radiation output of 10 mW to 1,000 mW.

[0021] Here, an ozone sensor is provided to detect the concentration of residual ozone (O3) remaining in the internal air after a chemical reaction of a plasma reaction section, and the operating time of the plasma discharge module is controlled based on the detected concentration of ozone (O3), and the intensity and amount of irradiation of ultraviolet (UV) rays to increase the activity of the catalytic reaction are automatically controlled.

[0022]

[0023] According to the present invention, the structure and control method of the plasma discharge module are improved, thereby extending the lifespan and increasing the performance.

[0024] In addition, by applying titanium dioxide (TiO₂) particles to the surface of the manganese dioxide (MnO₂) compound catalyst built into the catalyst filter section and irradiating it with ultraviolet (UV) rays, the activity of the catalytic reaction is increased, and ozone (O3) can be quickly removed from the inside.

[0025] As a result, it has the effect of significantly reducing the device manufacturing cost in relation to performance.

[0026] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

[0027]

[0028] FIG. 1 is a perspective view of a plasma air purification device according to one embodiment;

[0029] Figure 2 is a block diagram schematically showing the internal components of Figure 1;

[0030] Fig. 3 is a block diagram showing the cross-sectional structure of the arrangement of the plasma discharge module illustrated in Fig. 2;

[0031] Fig. 4 is an exemplary diagram showing the plasma discharge module illustrated in Fig. 3;

[0032] FIG. 5 is an exemplary diagram showing a method of applying power to the plasma discharge module illustrated in FIG. 3;

[0033] Fig. 6 is a block diagram of the catalyst filter unit and ultraviolet (UV) irradiation unit shown in Fig. 2;

[0034] Fig. 7 is a graph showing the ozone decomposition rate of the catalyst filter unit illustrated in Fig. 6; and

[0035] Fig. 8 is a test report showing the results of a sterilization test of a plasma air purifier according to one embodiment.

[0036]

[0037] Hereinafter, a plasma air purification device according to a preferred embodiment will be described with reference to the attached drawings.

[0038] FIG. 1 is a perspective view of a plasma air purification device according to one embodiment.

[0039] Referring to FIGS. 1 and 2, a plasma air purification device according to one embodiment includes a housing (10) including main components such as a plasma reaction unit (21), a catalyst filter unit (25), an ultraviolet irradiation unit (24), a blower fan (30), a pre-filter (32), a HEPA filter (33), and a device operation unit (40) inside, and a stand (11) may be installed at four corners of the lower part of the housing, or a caster may be provided with wheels that enable the device to be moved by pushing or pulling.

[0040] Here, the shape of the housing (10) can be formed in various forms, but it is preferable to form it in the shape of a square or cylindrical shape formed upright, but it is not limited thereto and can be manufactured in various shapes such as a sphere or pyramid shape.

[0041] Fig. 2 is a block diagram schematically showing the inside of Fig. 1, Fig. 3 is a block diagram showing a cross-sectional structure of the arrangement of the plasma discharge modules (20a to 20d) shown in Fig. 2, and Fig. 4 is an exemplary diagram showing an example of the plasma discharge module shown in Fig. 3.

[0042] The plasma discharge modules (20a to 20d) are devices for generating plasma under atmospheric pressure within the plasma reaction unit (21). A plurality of plasma discharge modules (20a to 20d) are arranged symmetrically with respect to the inner center of the plasma reaction unit (21), and preferably, four of them can be arranged symmetrically in the front, back, left, and right directions of the plasma reaction unit (21). In this case, the chemical reaction caused by the plasma can be evenly spread and act on the air to be purified passing through the plasma reaction unit (21), so that good performance can be expected, and there is an advantage of increasing the power supply efficiency of the plasma power supply unit (41) described later.

[0043] Meanwhile, if the capacity of the air purifier is large and a larger amount of plasma generation is required, two or more plasma discharge modules may be installed as a group.

[0044] The plasma power supply unit (41) supplies power to a plurality of plasma discharge modules (20a to 20d) by a control signal from the control unit (42), and transmits high voltage power to generate plasma under atmospheric pressure.

[0045] FIG. 5 is an exemplary diagram showing a method of supplying power to the plasma discharge modules (20a to 20d) illustrated in FIG. 3. For reference, FIG. 5 (a) to (d) show power supply cycle waveforms that show a state in which power is supplied to each of the four plasma discharge modules of FIG. 3.

[0046] Referring to FIG. 5, the control unit (42) controls the first plasma discharge module (20a), the second plasma discharge module (20b), and the third plasma discharge module (20c) and the fourth plasma discharge module (20d) to form a pair and alternately receive power at a regular cycle. For example, as shown in FIG. 5, when the power supply to the first plasma discharge module (20a) is turned ON, the other plasma discharge module (20b) forming the pair is turned OFF and no power is supplied, and after a certain period of time, when the power supplied to the first plasma discharge module (20a) is turned OFF, power is supplied to the other second plasma discharge module (20b). In this manner, power is controlled to be alternately supplied to the third and fourth plasma discharge modules (20c and 20d) in the same manner.

[0047] According to this, each of the plasma discharge modules (20a to 20d) receives power alternately at regular intervals to ensure continuity, so that plasma is continuously generated within the plasma reaction unit (21).

[0048] In addition, the time for which the plasma discharge modules (20a to 20d) are periodically supplied with power and are turned on can be controlled. Based on the concentration of ozone (O3) contained in the internal air detected by the ozone sensor unit (22) illustrated in FIG. 2, the time can be controlled within a duty ratio range of 20 to 50% per cycle as illustrated in (a) of FIG. 5, thereby controlling the amount of ozone (O3) generated by the plasma.

[0049] In (a) of Fig. 5, P represents voltage, Q represents cycle, and D represents duty ratio.

[0050] According to the above configuration, there is an advantage in that the performance and lifespan of the plasma air purification device can be extended by preventing the generation of high heat and the loss of discharge electrodes due to excessive energy concentration when power is continuously and simultaneously applied to a single or multiple plasma discharge modules. In addition, since each plasma discharge module (20a to 20d) can be evenly distributed and arranged within the plasma reaction unit (21), there is an effect in that a more uniform purification effect can be obtained for the air to be purified that is sucked in.

[0051] Referring to Fig. 2, the catalyst filter unit (25) is connected to the plasma reaction unit (21) and includes a catalyst for removing ozone (O3) gas generated inside. When plasma is generated inside the plasma reaction unit (21), harmful gases to the human body, such as ozone (O3) or nitrogen oxides (NOx), are generated together. At this time, the air containing the harmful gases generated is moved to the catalyst filter unit (25) by the blower fan (30), where it is decomposed by reaction with the catalyst and then discharged to the outside through the air discharge unit (34).

[0052] The catalyst used at this time is mainly composed of 72 mol% or more of manganese dioxide (MnO₂) and 16 mol% or more of copper oxide (CuO), and may include small amounts of potassium (K) and aluminum oxide (Al2O3). However, in order to increase the ozone (O3) decomposition efficiency of the catalyst, it may be formed in the form of pellets or balls with a diameter of 5 mm or less, containing 72 to 84 mol% of manganese dioxide (MnO₂) and 16 to 28 mol% of copper oxide (CuO), depending on environmental conditions such as temperature and flow rate.

[0053] In addition, the above catalyst filter unit (25) preferably has a flat honeycomb filter shape that contains the catalyst and allows easy gas passage.

[0054] Meanwhile, a method of rapidly promoting the ozone (O3) decomposition reaction of the catalyst filter unit (25) and maximizing the decomposition rate may be used, in which titanium dioxide (TiO₂) photocatalyst particles are applied to the surface of the catalyst and ultraviolet (UV) irradiation is applied thereto. In this case, the titanium dioxide (TiO₂) photocatalyst is preferably a manganese dioxide (MnO₂) compound catalyst having a structure in which it is evenly applied or coated at 50 to 80% on the surface of the catalyst in the form of small particles having a diameter of 100 nm or less, and the ultraviolet (UV) irradiation is preferably performed by using four or more semiconductor LEDs having a light source wavelength of 250 nm to 400 nm and an ultraviolet (UV) irradiation output of 10 mW to 1,000 mW to uniformly irradiate ultraviolet (UV) irradiation to a wide area.

[0055] The UV light source used here has generally been an UV lamp, but UV lamps contain mercury (Hg), a substance harmful to the human body, causing environmental pollution problems. In addition, they have a short lifespan of about 5,000 hours, requiring frequent replacement. However, with the recent development and supply of semiconductor UV LEDs of various specifications, it is desirable to use UV LEDs that have a long lifespan, good power efficiency, and a fast response time.

[0056] In general, manganese dioxide (MnO₂) - copper oxide (CuO) compound catalysts have a disadvantage in that their ozone (O3) decomposition efficiency decreases as the ambient temperature decreases. To compensate for this, the activity of the catalytic reaction can be increased by applying titanium dioxide (TiO₂) photocatalyst to the catalyst and irradiating it with ultraviolet (UV) light. In addition, during this process, the photochemical reaction between ultraviolet (UV) light and the photocatalyst can further remove microorganisms and harmful substances remaining in the air to be purified.

[0057] Referring to FIG. 2, air sucked into the air intake section (31) is purified by a chemical reaction of plasma in the plasma reaction section (21), and the concentration of ozone (O3) generated during the purification process and contained in the internal air is detected by the ozone sensor section (22), and based on this concentration value, the light output intensity and light quantity of the ultraviolet (UV) LED (23) built into the ultraviolet (UV) irradiation section (24) can be controlled to be adjusted, thereby reducing the power consumed by the ultraviolet (UV) irradiation section (24) and extending the lifespan of the ultraviolet (UV) LED (23).

[0058] Figure 7 is a graph showing the ozone (O3) decomposition rate by the catalyst filter unit (25) and ultraviolet (UV) irradiation unit (24) illustrated in Figure 6.

[0059] As shown in Fig. 7, it showed a decomposition efficiency of over 96% at a temperature condition of 20℃ or higher, and a decomposition rate of nearly 100% at 30℃ or higher. This shows that it is a significantly higher level under the same conditions compared to the commonly used high-temperature decomposition method, the method simply using manganese dioxide (MnO₂) as a catalyst, or the method of decomposing using activated carbon or the like as an adsorbent. Accordingly, the plasma air purification device according to the preferred embodiment has the advantage of excellent decomposition efficiency of harmful gases such as ozone (O3) and fast purification treatment.

[0060] Figure 8 shows the results of a sterilization test of floating microorganisms in indoor air by a plasma air purifier according to one embodiment.

[0061] Although the present invention has been described and illustrated with specific preferred embodiments above, it is clear that the present invention is not limited to the above-described embodiments, and various modifications and imitations are possible by those skilled in the art without departing from the spirit of the present invention.

Claims

1. In an air purification device that sterilizes microorganisms and removes harmful substances using atmospheric pressure plasma; An air purification device body that sucks in outside air, sterilizes floating microorganisms and removes harmful substances contained in the sucked air, and then discharges them to the outside; An air intake unit that sucks in external air into the interior of the air purifying device body; and an air exhaust unit that discharges the sucked internal air to the exterior. At least two atmospheric pressure plasma discharge modules installed inside the main body of the air purifier; A plasma reaction unit that performs the functions of sterilizing microorganisms and removing harmful substances by chemical reaction of the air sucked in from the air suction unit with the active species (including OH Radical) and ozone (O3) generated from the plasma discharge module; A catalyst filter unit that removes residual ozone (O3) generated in the plasma discharge module and remaining after a chemical reaction in the plasma reaction unit; An ultraviolet (UV) irradiation section for rapidly promoting the ozone (O3) decomposition reaction of the above catalyst filter section; An ozone sensor unit that detects the concentration of ozone (O3) contained in the internal air after a chemical reaction of the above plasma reaction unit; A power supply unit that supplies high voltage power to the plasma discharge module; A control unit that controls the power supply of the above power supply unit; and Includes a pre-filter and a HEPA filter installed between the air intake and the plasma reaction unit; The air sucked in through the air intake section passes through the pre-filter, HEPA filter, plasma reaction section, ultraviolet irradiation section, and catalyst filter section in sequence, is purified, and then discharged through the air exhaust section. The catalyst of the above catalyst filter part is in the form of a pellet or ball having a diameter of 5 mm or less containing 72 to 84 mol% of manganese dioxide (MnO₂) and 16 to 28 mol% of copper oxide (CuO), and includes a gas-passing catalyst filter having a manganese dioxide (MnO₂)-copper oxide (CuO) compound catalyst built therein, wherein titanium dioxide (TiO₂) photocatalyst particles having a diameter of 100 nm or less are evenly applied or coated on the surface of the catalyst at 50 to 80%, An atmospheric pressure plasma air purification device characterized in that the intensity and amount of ultraviolet (UV) irradiation that promotes ozone (O3) decomposition reaction in the catalyst filter unit are automatically controlled based on the concentration of ozone (O3) contained in the internal air detected by the ozone sensor unit.

2. In paragraph 1, An atmospheric pressure plasma air purification device characterized in that the plasma discharge module is controlled to operate (ON) by receiving power at regular intervals within a duty ratio range of 20 to 50% per cycle, and is automatically controlled based on the concentration of ozone (O3) contained in the internal air detected by the ozone sensor unit.

3. In paragraph 1, An atmospheric pressure plasma air purification device characterized in that the UV generating device of the above UV irradiation unit uses at least four semiconductor LEDs having a light wavelength of 250 nm to 400 nm and an UV light emission output of 10 mW to 1,000 mW to irradiate UV onto the catalyst filter unit, thereby increasing the activity of the catalytic reaction and promoting the ozone (O3) decomposition reaction.

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