Patent Description:
In the past, a processing apparatus that uses high-voltage plasma in the atmosphere for oxidation processing on NO in exhaust gases discharged from engines and other internal combustion engines has been proposed.

To generate high-voltage plasma, in the case of utilizing a voltage conversion transformer often used in a low frequency band of <NUM> or less, it is necessary to reduce the inductance (reactance) at high frequencies greater than or equal to <NUM>. This means that the number of coil turns and the coil size need to be reduced and the diameter of the coil used as an electric wire becomes small, thus resulting in a problem that it is not possible to input a large amount of power.

On the other hand, in the case of increasing the voltage while maintaining the characteristic impedance low at, for example, 50Ω without the above voltage conversion, power of <NUM> kW (= <NUM><NUM>·<NUM>/<NUM>) is necessary for a voltage of <NUM> V, for instance. It is difficult in practice to provide a power source device that inputs such an amount of power.

In view of the above, Non Patent Literature (NPL) <NUM> below proposes a plasma reactor that generates plasma between electrodes by applying, to the electrodes, high-voltage pulses having a frequency of several kilohertz and a peak voltage in a range of from <NUM> V to <NUM> V for the oxidation of NO in exhaust gases discharged from engines and other internal combustion engines.

[NPL <NUM>] Complete NOx Removal Technology Using Nonequilibrium Plasma and Chemical Process (Performances of Ordinary and Barrier Type Plasma Reactors), <NPL>).

<CIT> (<NUM>-<NUM>-<NUM>) discloses an example of a high voltage plasma generator configured to generate a resonance by electric power feeding of a high frequency signal.

However, conventional air purification systems serving as plasma reactors have a problem that sufficient power is not supplied to the electrodes due to impedance mismatching of the signal of the applied pulse voltage. In addition, with high-voltage pulses of several kilohertz, the time between high-voltage pulses is longer than the electric discharge time caused by high-voltage pulses. At this time, electrons once ionized from gas recombine, and thus a large amount of energy needs to be supplied for electron ionization every time high-voltage pulses are applied. As a result, the apparatus has a low power efficiency. Therefore, even if plasma is generated, the amount of bacteria, viruses, etc. in the air decomposed by plasma is low relative to the input power.

In addition, it is difficult for conventional air purification systems to reduce: dissociation of nitrogen molecules which is, along with dissociation of oxygen molecules, induced by an intense electric field corresponding to a pulse apex value; and nitrogen oxides generated by the dissociation of nitrogen molecules. It is also difficult with the conventional technology to enable generation of ozone while preventing generation of nitrogen oxides.

In view of this, in order to address the issues described above, the present disclosure has an object to provide an air purification system and protective clothing capable of decomposing bacteria, viruses etc. in the air by efficiently generating plasma while reducing input power as compared to the conventional technology.

In order to achieve the above object, an air purification system according to an aspect of the present disclosure is an air purification system that generates plasma using voltage, the air purification system including: a first electrode that generates electromagnetic resonance when power is supplied; a second electrode disposed surrounding the first electrode in a state of being separated from the first electrode; a power feeder that supplies power to the first electrode; an electric field probe that measures an intensity of an electric field between the first electrode and the second electrode; and a controller that controls the power supplied to the first electrode, wherein the controller performs control by adjusting a frequency of the power supplied to the first electrode and a position at which the power is supplied to the first electrode, to maximize an output value of a signal indicating the intensity of the electric field measured by the electric field probe.

The air purification system further incorporates therein a detector that monitors the amounts of ozone and nitrogen oxides generated. With the amounts of ozone and nitrogen oxides generated set as targets to be controlled, the air purification system changes alternating current (AC) power, the frequency, and the power feeding point to be able to control the electric field applied to plasma so that an energy at which oxygen molecules are dissociated by plasma and ozone is thereby generated but nitrogen molecules are not dissociated and generation of nitrogen oxides is thereby minimized is inputted to gas molecules.

In order to achieve the above object, protective clothing according to an aspect of the present disclosure includes: an air purification system; and a covering body that is provided with the air purification system and covers a surface of a body of a person, and the air purification system purifies air taken in from outside and supplies purified air into the covering body.

Note that these general or specific aspects may be implemented by a system, a method, an integrated circuit, a computer program, or a computer-readable recording medium such as CD-ROM, or by any combination thereof.

The invention relates to an air purification system as defined in claim <NUM>. Advantageous embodiments are disclosed in the dependent claims.

According to the present disclosure, it is possible to decompose bacteria, viruses etc. in the air by efficiently generating plasma while reducing input power as compared to the conventional technology.

Hereinafter, embodiments according to the present invention are described in detail with reference to the drawings. The embodiments described below each illustrate one specific example of the present invention. Therefore, the numerical values, shapes, materials, constituent elements, the arrangement and connection of the constituent elements, steps, and the processing order of the steps etc. shown in the embodiments below are mere examples, and are not intended to limit the present invention. Accordingly, among the constituent elements included in the following embodiments, constituent elements not recited in any of the independent claims are described as optional constituent elements.

Note that the drawings are represented schematically and are not necessarily precise illustrations. In addition, in the figures, the same reference signs are given to essentially the same constituent elements, and redundant descriptions may be omitted or simplified.

Also, in the following embodiments, the term "substantially" is used. For example, the term "substantially the central portion" is intended to mean not only a portion that is exactly central, but also a portion that is essentially central, that is, including several percentages of margins of errors, for instance. Also, the term "substantially the central portion" means a central portion within a range in which advantageous effects of the present disclosure can be yielded. The same applies to other expressions including "substantial".

Hereinafter, an air purification system and protective clothing according to embodiments of the present disclosure are described.

A configuration of air purification system <NUM> according to the present embodiment is described.

<FIG> is a schematic diagram illustrating air purification system <NUM> according to Embodiment <NUM>. <FIG> is a schematic diagram schematically illustrating, for example, the flow of air taken into air purification system <NUM> according to Embodiment <NUM> and changes of power feeding point F at which power feeder <NUM> supplies power to linear electrode <NUM>.

As illustrated in <FIG> and <FIG>, air purification system <NUM> is an air purifier that decomposes, that is, kills, and removes bacteria, viruses etc., with use of a high-voltage plasma generation device capable of generating high-frequency plasma (hereinafter simply referred to as "plasma") using a high voltage in the high-frequency band. In the present embodiment, air purification system <NUM> generates plasma using a high voltage obtained by modulating a carrier wave having a frequency in a range of from <NUM> to <NUM>. Note that a high voltage is, for example, a voltage of approximately <NUM> V or higher. The high voltage in the present embodiment may be in a range of from <NUM><NUM> V to <NUM><NUM> V.

Also, the high frequency band refers to frequencies of approximately <NUM> or higher. The high frequency band in the present embodiment may be at least <NUM> and at most <NUM>. The plasma in the present embodiment is atmospheric pressure plasma generated in the atmosphere at the normal pressure. Note that air purification system <NUM> can also decompose and remove particulates floating in the air, such as dust, pollen, mites, and smoke.

Air purification system <NUM> includes first housing <NUM>, linear electrode <NUM>, power feeder <NUM>, electric field probe <NUM>, second amplifier <NUM>, cymoscope <NUM>, voltage converter <NUM>, actuator <NUM>, controller <NUM>, duct <NUM>, second housing <NUM>, filter <NUM>, and fan <NUM>.

First housing <NUM> forms (defines) space 10a that is elongated and accommodates linear electrode <NUM> in a state of being separated from linear electrode <NUM>. First housing <NUM> is grounded and thus functions as a ground electrode. First housing <NUM> is disposed surrounding linear electrode <NUM> to accommodate linear electrode <NUM>. Supports 16a for coupling linear electrode <NUM> are disposed and fixed in space 10a, which is the inside of first housing <NUM>. Supports 16a are support components that separate linear electrode <NUM> from the inner wall surface of first housing <NUM> and support linear electrode <NUM> in a predetermined orientation. Supports 16a are formed using a material such as polytetrafluoroethylene, for example.

First housing <NUM> is formed using a conductive material having high electrical conductivity, such as silver, copper, or aluminum, for example. First housing <NUM> is an example of a second electrode.

First housing <NUM> is elongated in the same direction as the longitudinal direction of linear electrode <NUM> so as to accommodate linear electrode <NUM>. In the present embodiment, first housing <NUM> is shaped according to the shape of linear electrode <NUM>, e.g., cylindrical, but the shape of first housing <NUM> is not particularly limited.

First housing <NUM> includes inlet 12a through which air is taken in and vent 12b through which the air taken in through inlet 12a is discharged to duct <NUM>. Inlet 12a is formed on one end side of first housing <NUM> in the longitudinal direction, and vent 12b is formed on the other end side of first housing <NUM> in the longitudinal direction. The air etc. that is present outside first housing <NUM> is taken in and passes through inlet 12a. Duct <NUM> is connected to vent 12b. The air etc. that has passed through inlet 12a and flowed through space 10a of first housing <NUM> passes through vent 12b and flows into duct <NUM>.

Also, first housing <NUM> includes frame <NUM> which is like a mesh. Frame <NUM> is provided at inlet 12a and covers the opening surface of inlet 12a.

Linear electrode <NUM> is an elongated electrode which is long in a predetermined direction. Linear electrode <NUM> is accommodated in first housing <NUM> and is provided in a state of being separated from first housing <NUM>. Specifically, linear electrode <NUM> is disposed in a predetermined orientation in the longitudinal direction of first housing <NUM> and fixed to first housing <NUM> via supports 16a in a state of being coupled to supports 16a to be separated from the inner wall surface of first housing <NUM>.

Linear electrode <NUM> is formed using a conductive material having high electrical conductivity, such as silver, copper, or aluminum, for example. Linear electrode <NUM> is an example of a first electrode. Note that the first electrode may be a plate-shaped electrode and is not limited to linear electrode <NUM>.

As illustrated in <FIG>, modulated or unmodulated AC power supplied from power feeder <NUM> is applied to power feeding point F of linear electrode <NUM>. Power feeding point F is substantially the central portion of linear electrode <NUM> in the longitudinal direction and is the point to which modulated or unmodulated AC power supplied from power feeder <NUM> is applied. According to the output value (e.g., output voltage) of a signal indicating the intensity of the electric field measured by electric field probe <NUM>, the position of power feeding point F is changed by a predetermined distance in the longitudinal direction of linear electrode <NUM> from substantially the half-length position of linear electrode <NUM>. The length of linear electrode <NUM> is the sum of the length of the main body of linear electrode <NUM> and the lengths of first dielectric <NUM> and second dielectric <NUM> in the longitudinal direction of linear electrode <NUM>.

First dielectric <NUM> and second dielectric <NUM> are provided at an end of linear electrode <NUM> (an end portion closer to inlet 12a). First dielectric <NUM> and second dielectric <NUM> are provided to linear electrode <NUM> so as not to expose one end of linear electrode <NUM>. First dielectric <NUM> is a dielectric material which is highly resistant to heat and is disposed around linear electrode <NUM> at one end of linear electrode <NUM>. Second dielectric <NUM> is a dielectric material which is highly resistant to heat and is disposed on the end surface of one end of linear electrode <NUM>. Each of first dielectric <NUM> and second dielectric <NUM> is, for example, ceramic such as quartz glass or alumina. In the present embodiment, first dielectric <NUM> is synthetic quartz and second dielectric <NUM> is alumina.

Linear electrode <NUM> generates resonance in first housing <NUM> when AC power is supplied from power feeder <NUM>. AC power is supplied to linear electrode <NUM> to generate resonance at maximum efficiency.

<FIG> is a schematic diagram illustrating changes of the half wavelength during resonance in air purification system <NUM> according to Embodiment <NUM>. The half wavelength during resonance in space 10a of first housing <NUM> represents the sum of the length of linear electrode <NUM> in the longitudinal direction and the length of plasma generated in plasma generation region P between one end of linear electrode <NUM> and inlet 12a of first housing <NUM> (the length in parallel to the longitudinal direction of linear electrode <NUM>). Part a of <FIG> illustrates a state in which no plasma is generated in plasma generation region P. As illustrated by the dashed lines, the half wavelength of an electromagnetic wave during resonance of the electromagnetic wave in linear electrode <NUM> is the length of linear electrode <NUM> in the longitudinal direction. In other words, λ/<NUM> = L, where λ/<NUM> is the half-wavelength of the electromagnetic wave during resonance of the electromagnetic wave in linear electrode <NUM>, and L is the length of linear electrode <NUM>. Next, part b of <FIG> illustrates the state in which plasma starts being generated in plasma generation region P. As illustrated by the dashed lines, the half wavelength of the electromagnetic wave during resonance of the electromagnetic wave is the sum of the length of linear electrode <NUM> in the longitudinal direction and the length of plasma. In other words, λ/<NUM> = L + d, where d (variable) is the length of plasma. Next, part c of <FIG> illustrates the state in which plasma has reached the maximum size in plasma generation region P, and illustrates the half wavelength of the electromagnetic wave during resonance, as illustrated by the dashed lines.

In the present embodiment, the length of linear electrode <NUM> is set to effectively generate plasma in plasma generation region P in the frequency band of from <NUM> to <NUM>.

Plasma generation region P is a region between one end of linear electrode <NUM> and the opening surface of inlet 12a, and is a region in space 10a of first housing <NUM> for generating plasma. A first shortest distance between one end of linear electrode <NUM> and the opening surface of inlet 12a in plasma generation region P is shorter than a second shortest distance between the other end of linear electrode <NUM> and the opening surface of vent 12b. By making the first shortest distance shorter than the second shortest distance, plasma is effectively generated in plasma generation region P. When first housing <NUM> is viewed in the longitudinal direction, plasma generation region P covers and overlaps the opening surface of inlet 12a. In plasma generation region P, the size of plasma generated and the projection surface area facing the opening surface change according to the AC power supplied to linear electrode <NUM>.

As illustrated in <FIG> and <FIG>, through supply, via first amplifier <NUM>, of modulated or unmodulated AC current outputted by frequency changing oscillator + modulator <NUM> controlled by controller <NUM>, power feeder <NUM> supplies the modulated or unmodulated AC current to power feeding point F of linear electrode <NUM>. Power feeder <NUM> includes frequency changing oscillator + modulator <NUM>, first amplifier <NUM>, power feeding terminal <NUM>, and power feeding line <NUM>.

Frequency changing oscillator + modulator <NUM> has the functions of both a voltage control oscillator and a modulator that supply modulated AC power or unmodulated AC current to power feeding point F of linear electrode <NUM> via first amplifier <NUM>. Specifically, by being controlled by controller <NUM> to maximize the output value of the signal measured by electric field probe <NUM> (or to cause the output value to reach a local maximum), frequency changing oscillator + modulator <NUM> controls the frequency of the AC power supplied to linear electrode <NUM>. In other words, frequency changing oscillator + modulator <NUM> is controlled by controller <NUM> so that the phase of the current (or voltage) when supplying the AC power amplified by first amplifier <NUM> to power feeding point F and the phase of the current during resonance caused in space 10a of first housing <NUM> become the same phase (the phases are synchronized). The frequency changing oscillator + modulator outputs, to first amplifier <NUM>, the AC current that is controlled to synchronize these phases.

First amplifier <NUM> amplifies the AC power outputted by frequency changing oscillator + modulator <NUM>, and supplies the amplified AC power to power feeding point F via power feeding line <NUM>. Although first amplifier <NUM> amplifies the AC power by a predetermined factor, the amount of amplification may be settable as appropriate.

Power feeding terminal <NUM> is a connection terminal for supplying the AC power amplified by first amplifier <NUM> to power feeding point F of linear electrode <NUM>. Power feeding terminal <NUM> is fixed to first housing <NUM> to electrically connect power feeding line <NUM> and power feeding point F of linear electrode <NUM>. Power feeding terminal <NUM> is a holder that holds power feeding line <NUM> against first housing <NUM>.

Power feeding line <NUM> is a power line for supplying the AC power amplified by first amplifier <NUM> to power feeding point F of linear electrode <NUM>. Power feeding line <NUM> is held by power feeding terminal <NUM> and can be moved, together with power feeding terminal <NUM>, by actuator <NUM> in the longitudinal direction of linear electrode <NUM>. Note that power feeding line <NUM> may be the only constituent element which can be moved by actuator <NUM> in the longitudinal direction of linear electrode <NUM>.

Electric field probe <NUM> is a sensor that measures the intensity of the electric field between linear electrode <NUM> and first housing <NUM> when the amplified AC power is supplied to linear electrode <NUM>. Electric field probe <NUM> measures the intensity of the electric field in space 10a of first housing <NUM>, and outputs a measurement signal (a measured signal) whose output value is proportional to the intensity of the electric field to cymoscope <NUM> via second amplifier <NUM>. As described later, electric field probe <NUM> outputs a measurement signal whose output value is maximized (or reaches a local maximum) by controller <NUM> controlling power feeder <NUM> and voltage converter <NUM>.

Electric field probe <NUM> is fixed to first housing <NUM>. Electric field probe <NUM> is disposed at a position on first housing <NUM> which is closer to vent 12b of first housing <NUM> and which faces the other end of linear electrode <NUM>.

Second amplifier <NUM> amplifies the measurement signal outputted by electric field probe <NUM>, and outputs the amplified measurement signal to cymoscope <NUM>. Although second amplifier <NUM> amplifies the measurement signal by a predetermined factor, the amount of amplification may be settable as appropriate.

Cymoscope <NUM> obtains the measurement signal amplified by second amplifier <NUM>, and performs detection on the measurement signal obtained. For example, cymoscope <NUM> performs detection on the measurement signal using a Schottky barrier diode. Cymoscope <NUM> outputs, to controller <NUM>, a signal that indicates the detection result of the detection performed on the measurement signal. The signal indicating the detection result is a signal that indicates a result of monitoring the intensity of the electric field in first housing <NUM>.

Voltage converter <NUM>, by being controlled by controller <NUM>, adjusts the voltage that voltage converter <NUM> supplies to actuator <NUM> based on a variable power source such as an external power source. By being controlled by controller <NUM> according to the detection result of the detection performed on the measurement signal by cymoscope <NUM>, voltage converter <NUM> adjusts the voltage that voltage converter <NUM> supplies to actuator <NUM>. In other words, voltage converter <NUM> drives actuator <NUM> by adjusting the voltage that voltage converter <NUM> applies to actuator <NUM>.

Actuator <NUM> is coupled to power feeding terminal <NUM> of power feeder <NUM>, and is driven when a voltage is applied by voltage converter <NUM>. Actuator <NUM> is a piezoelectric element etc. that expands and contracts when driven by voltage application, for example. When driven by voltage application by voltage converter <NUM>, actuator <NUM> moves power feeding line <NUM> in the longitudinal direction of linear electrode <NUM>. In other words, by moving power feeding line <NUM>, actuator <NUM> changes the position of power feeding point F at which AC power is supplied to linear electrode <NUM>. Specifically, as illustrated in <FIG>, actuator <NUM> adjusts the position of power feeding point F with respect to linear electrode <NUM> by moving the position of power feeding point F with respect to linear electrode <NUM> by distance Δx in the longitudinal direction of linear electrode <NUM>. Given that an arbitrary reference position has been set, distance Δx is the amount of change in position with respect to the reference position, and is dependent on voltage Vin<NUM> supplied from voltage converter <NUM>. The reference position is, for example, the initial position in the state in which AC power is not supplied to linear electrode <NUM>, or the position at the half-length of linear electrode <NUM> in the longitudinal direction.

With linear electrode <NUM>, the equivalent electrode length changes because the average conductivity varies according to the density of plasma generated. This results in a slight movement in the position of the matching power feeding point. The higher the resonance Q factor is, the higher the efficiency of plasma generation is with respect to the input power and the higher the efficiency of virus decomposition is. However, the higher the Q factor is, the more important it becomes to control power feeding point F and the resonant frequency in accordance with this slight movement w. The present disclosure provides a solution to this problem.

Controller <NUM> is, for example, a microcontroller. Controller <NUM> controls power feeder <NUM> and voltage converter <NUM>.

By controlling power feeder <NUM>, controller <NUM> controls the AC power supplied to linear electrode <NUM>. That is to say, controller <NUM> controls the frequency of the AC power supplied to linear electrode <NUM>, to maximize the output value of the signal measured by electric field probe <NUM>. Specifically, controller <NUM> controls the frequency of the AC power supplied to linear electrode <NUM>, by controlling frequency changing oscillator + modulator <NUM> according to the detection result of the detection performed on the measurement signal by cymoscope <NUM>. At this time, controller <NUM> controls frequency changing oscillator + modulator <NUM> so that the phase of the current (or voltage) supplied to power feeding point F and the phase of the current (or voltage) during resonance caused in space 10a of first housing <NUM> become the same phase.

By controlling voltage converter <NUM>, controller <NUM> also controls the voltage applied to actuator <NUM>. That is to say, controller <NUM> controls the position at which the AC power is supplied to linear electrode <NUM>, to maximize the output value of the signal measured by electric field probe <NUM>. In other words, controller <NUM> adjusts the position of power feeding point F by controlling actuator <NUM> according to the detection result of the detection performed by cymoscope <NUM> on the measurement signal.

In automatic control of maintaining this resonance state, the detection result of the detection performed on the measurement signal by cymoscope <NUM> (the detection result indicates a local maximum in the resonance state) is a control quantity, and the frequency of the power outputted from frequency changing oscillator + modulator <NUM> and the position of power feeding point F corresponding to the output of voltage converter <NUM> correspond to an adjustment quantity in this automatic control.

Controller <NUM> performs feedback control by adjusting the frequency of the AC power supplied to linear electrode <NUM> and the voltage applied to actuator <NUM> for adjusting the position of feeding point F, to maximize the output value of the measurement signal measured by electric field probe <NUM> which senses the intensity of the electric field in first housing <NUM>.

Duct <NUM> is a pipe which connects space 10a of first housing <NUM> and space 50a of second housing <NUM> and through which the air taken in through inlet 12a of first housing <NUM> passes. One end of duct <NUM> is connected to vent 12b of first housing <NUM>, and the other end of duct <NUM> is connected to vent 50b of second housing <NUM>. That is to say, duct <NUM> guides the air flowing in space 10a of first housing <NUM> to space 50a of second housing <NUM>.

Second housing <NUM> forms (defines) space 50a that accommodates filter <NUM> and fan <NUM>. Filter <NUM> and fan <NUM> are disposed and fixed in space 50a, which is the inside of second housing <NUM>. Second housing <NUM> is formed using a conductive material having high electrical conductivity, such as silver, copper, or aluminum. Second housing <NUM> may be an example of a component of the second electrode.

In the present embodiment, the shape of second housing <NUM> is an elongated cylindrical shape, for example, but is not particularly limited.

Second housing <NUM> includes vent 50b through which the air guided by duct <NUM> passes and outlets <NUM> through which the air that has entered through vent 50b is discharged to the outside of second housing <NUM>. Vent 50b is formed on one end of second housing <NUM> in the longitudinal direction, and outlets <NUM> are formed on the other end of second housing <NUM> in the longitudinal direction. Duct <NUM> is connected to vent 50b. The air etc. that has passed through first housing <NUM> and duct <NUM> passes through vent 50b. Outlets <NUM> allow discharge, to the outside, of the air that has passed through vent 50b and then passed through filter <NUM> etc. in space 50a of second housing <NUM>.

Filter <NUM> can remove ozone contained in the air generated by plasma generation when the air flowing from the vent 50b side to the outlets <NUM> side of second housing <NUM> (the air taken in through inlet 12a of first housing <NUM>) passes through filter <NUM>. Filter <NUM> is disposed in the vicinity of outlets <NUM> in space 50a of second housing <NUM> to remove ozone. Such filter <NUM> includes activated carbon.

Filter <NUM> can also adsorb, for example, remnants of bacteria, viruses, etc. Filter <NUM> adsorbs, for example, remnants of bacteria, viruses, etc. contained in the air that has passed through first housing <NUM> and duct <NUM>.

Fan <NUM> is a blower that generates an airflow inside first housing <NUM>, duct <NUM>, and second housing <NUM> to allow intake of the air through inlet 12a of first housing <NUM> and discharge of the air through outlets <NUM> of second housing <NUM>. Fan <NUM> is located in space 50a of second housing <NUM>. In the present embodiment, fan <NUM> is disposed closer to outlets <NUM> of second housing <NUM> than filter <NUM> is. When the electric motor of fan <NUM> drives the propeller of fan <NUM> to rotate (i.e., when fan <NUM> is driven), the air is taken in through inlet 12a of first housing <NUM> and passes through space 10a of first housing <NUM> and the inside of duct <NUM> in the stated order, and then reaches space 50a of second housing <NUM>, passes through filter <NUM>, and is discharged through outlets <NUM> of second housing <NUM>.

Note that the driving of fan <NUM> may be controlled by controller <NUM>. That is to say, controller <NUM> may control the driving of fan <NUM> when controlling power feeder <NUM> and voltage converter <NUM>.

A description is given of the relationship between the frequency of the AC power supplied to power feeding point F and the position of power feeding point F at which the AC power is supplied, that maximizes the output value of the signal measured by electric field probe <NUM>. The following expressions (<NUM>) to (<NUM>) are given, where Vin<NUM> denotes a voltage that voltage converter <NUM> supplies to actuator <NUM>; v<NUM> denotes a variable dependent on voltage Vin<NUM>; Vin<NUM> denotes a control voltage of the frequency changing oscillator included in frequency changing oscillator + modulator <NUM> which corresponds to the frequency of the power supplied to power feeding point F; v<NUM> denotes a variable dependent on voltage Vin<NUM>; and V<NUM> denotes a voltage of the output signal of the cymoscope which indicates the detection result that cymoscope <NUM> outputs to controller <NUM> and which corresponds to the electric field at the electrode end. <NUM>] <MAT>
[Math. <NUM>] <MAT>
[Math. <NUM>] <MAT>.

Using Expressions <NUM> through <NUM> above, function g(v<NUM>, v<NUM>) that maximizes the output value of the signal measured by electric field probe <NUM> is calculated. In other words, the maximum value of g(v<NUM>, v<NUM>) is calculated.

Satisfying Expressions <NUM> and <NUM> below is a condition for maximizing the electric field. On the basis of g(v<NUM>, v<NUM>), new functions are defined as shown in Expressions <NUM> and <NUM>. <NUM>] <MAT>
[Math. <NUM>] <MAT>
[Math. <NUM>] <MAT>
[Math. <NUM>] <MAT>.

Calculation, using Expressions <NUM> and <NUM>, of point (v<NUM>, v<NUM>) at which each of g<NUM>(v<NUM>,v<NUM>) and g<NUM>(v<NUM>,v<NUM>) becomes <NUM> is expressed as Expressions <NUM> and <NUM> below. <NUM>] <MAT>
[Math. <NUM>] <MAT>.

In Expressions <NUM> and <NUM>, assume <MAT> and <MAT> , and ignore <MAT> Then, Expressions <NUM> and <NUM> in which <MAT> and <MAT> are used are expressed as below. <NUM>] <MAT>
[Math. <NUM>] <MAT>.

Solving Expressions <NUM> and <NUM> leads to Expressions <NUM> and <NUM>. <NUM>] <MAT>
[Math. <NUM>] <MAT>.

Operations of air purification system <NUM> according to the present embodiment are described.

As illustrated in <FIG> and <FIG>, when air purification system <NUM> is driven, controller <NUM> controls the driving of power feeder <NUM> and voltage converter <NUM>. At this time, controller <NUM> may drive fan <NUM> along with power feeder <NUM> and voltage converter <NUM>.

By controlling power feeder <NUM>, controller <NUM> causes generation of plasma in plasma generation region P. When the rotation of fan <NUM> causes intake of, for example, the air containing bacteria, viruses, etc. through inlet 12a of first housing <NUM>, the air passes through plasma generation region P formed between inlet 12a and linear electrode <NUM>.

As illustrated in <FIG>, bacteria, viruses, etc. contained in the air are decomposed and sterilized by plasma when passing through plasma generation region P. For example, molecules, atoms, ions, electrons, etc. dissociated by plasma generation, as well as ozone and ultraviolet rays generated by plasma, collide with and decompose bacteria, viruses etc. Particulates contained in the air, such as dust, pollen, mites, and smoke are also decomposed. <FIG> is a schematic diagram illustrating how viruses are decomposed in plasma generation region P of air purification system <NUM> according to Embodiment <NUM>.

As illustrated in <FIG>, dust such as remnants of bacteria, viruses, etc. that have been decomposed passes through space 10a of first housing <NUM> together with the air, flows into second housing <NUM> via duct <NUM>, and is removed from the air by being adsorbed by filter <NUM> of second housing <NUM>. As a result, the air that has passed through filter <NUM> is purified and discharged through outlets <NUM> of second housing <NUM>. In such a manner, air purification system <NUM> can remove, from the air, bacteria, viruses etc. contained in the air, and supply the purified air.

Note that as a variation of Embodiment <NUM>, in the case of using above-described filter <NUM> as first filter <NUM>, air purification system <NUM> may include second filter <NUM> different from first filter <NUM>.

<FIG> is a schematic diagram schematically illustrating, for example, the flow of air taken into air purification system <NUM> according to the variation of Embodiment <NUM> and changes of power feeding point F at which power feeder <NUM> supplies power to linear electrode <NUM>.

As illustrated in <FIG>, second filter <NUM> is disposed between first filter <NUM> and vent 50b of second housing <NUM>. In other words, second filter <NUM> is disposed upstream of first filter <NUM> in the air flow. Second filter <NUM> is, for example, an NO<NUM> filter.

Advantageous effects of air purification system <NUM> according to the present embodiment are described.

As described above, air purification system <NUM> according to the present embodiment is air purification system <NUM> that generates plasma using voltage, and includes: linear electrode <NUM> that generates electromagnetic resonance when AC power is supplied; first housing <NUM> disposed surrounding linear electrode <NUM> in a state of being separated from linear electrode <NUM>; power feeder <NUM> that supplies AC power to linear electrode <NUM>; electric field probe <NUM> that measures the intensity of an electric field between linear electrode <NUM> and first housing <NUM>; and controller <NUM> that controls the AC power supplied to linear electrode <NUM>. Controller <NUM> performs control by adjusting the frequency of the power supplied to linear electrode <NUM> and the position at which the power is supplied to linear electrode <NUM>, to maximize the output value of a signal indicating the intensity of the electric field measured by electric field probe <NUM>.

With this, it is possible to generate plasma between linear electrode <NUM> and first housing <NUM> by supplying AC power to linear electrode <NUM>. Controller <NUM> controls the frequency of the AC power and the position at which the AC power is supplied to linear electrode <NUM>. Therefore, the AC power can be synchronized with (follow) a change in the resonance frequency caused by plasma generation so that the phase of the current when supplying the AC power to linear electrode <NUM> and the phase of the current during resonance caused in linear electrode <NUM> become the same phase. At this time, since the AC power synchronized with a change in the resonance frequency can be supplied to linear electrode <NUM>, it is possible to perform control that allows maintaining an electromagnetic resonance state at all times and allows maximizing at all times the output value of the signal measured by electric field probe <NUM>.

Accordingly, air purification system <NUM> can decompose bacteria, viruses etc. contained in the air by efficiently generating plasma while reducing input power as compared to the conventional technology.

In particular, since air purification system <NUM> can reduce the input power, creation of a high-voltage circuit, a step-up transformer, etc., is less likely to be difficult, and power feeder <NUM>, which is the power source of air purification system <NUM>, does not become greater in size. Air purification system <NUM> can also reduce heat generation in power feeder <NUM> caused by an increase in the current value and reduce damages and the like of the electrodes caused by heat generation. Therefore, the manufacturing cost of air purification system <NUM> does not rise.

Note that air purification system <NUM> may be designed to increase the Q factor of resonance, in which case the AC power inputted to linear electrode <NUM> can be reduced.

Note that there are also methods for removing bacteria, viruses, etc. by chemical means using, for example, peracetic acid, hydrogen peroxide, ethylene oxide gas, or ozone; however, there are concerns about their impacts on the human body. In addition, there are also methods for removing bacteria, viruses, etc. by physical means such as high-pressure steam, radiation, and ultraviolet rays; however, these methods are not realistic in terms of, for example, their impacts on the human body, restrictions on usage conditions, and low energy efficiency. In contrast, air purification system <NUM> according to the present embodiment can remove bacteria, viruses, etc. more inexpensively and effectively than the conventional technology.

Air purification system <NUM> according to the present embodiment includes actuator <NUM> that changes the position of power feeding point F at which power feeder <NUM> supplies the AC power to linear electrode <NUM>. Controller <NUM> adjusts the position of power feeding point F by controlling actuator <NUM>.

With this, controller <NUM> can change the position of power feeding point F to maximize the output value of the signal measured by electric field probe <NUM>. Therefore, with air purification system <NUM>, the AC power can easily follow a change in the resonance frequency in electromagnetic resonance caused by plasma generation.

In air purification system <NUM> according to the present embodiment, controller <NUM> controls actuator <NUM> and power feeder <NUM> by controlling two parameters, namely the frequency and the position of power feeding point F on linear electrode <NUM>, to cause the output voltage of electric field probe <NUM> to reach a local maximum. In other words, controller <NUM> performs feedback control by adjusting the frequency and the position of power feeding point F on linear electrode <NUM>, to cause the output voltage of electric field probe <NUM> to reach a local maximum.

With this, since the resonance can be maintained, plasma can be efficiently generated while more reliably reducing the input power.

In air purification system <NUM> according to the present embodiment, first housing <NUM> is a housing including inlet 12a through which the air is taken in. Air purification system <NUM> includes filter <NUM> that is disposed in the vicinity of outlets <NUM> through which the air taken in through inlet 12a is discharged, and that, when the air taken in through inlet 12a passes through, removes nitrogen oxides and ozone generated by a plasma reactor including linear electrode <NUM> and first housing <NUM>.

With this, it is possible to supply purified air from which dust such as remnants of bacteria and viruses, etc., decomposed by plasma has been removed.

In air purification system <NUM> according to the present embodiment, linear electrode <NUM> is an elongated electrode. First housing <NUM> forms, in the longitudinal direction of linear electrode <NUM>, space 10a that is elongated and accommodates linear electrode <NUM>. In space 10a, plasma generation region P for generating plasma is provided between linear electrode <NUM> and inlet 12a of first housing <NUM>.

With this, since plasma generation region P is provided in the vicinity of inlet 12a, it is possible to ensure that the air passing through inlet 12a passes through plasma generation region P. Therefore, bacteria, viruses, etc. contained in the air can be reliably decomposed.

Air purification system 2a according to the present embodiment is described.

The present embodiment is different from Embodiment <NUM> in that air purification system 2a according to the present embodiment further includes second filter unit <NUM>, heater <NUM>, third filter unit <NUM>, and first detector 105a. A configuration of main body 1a in air purification system 2a according to the present embodiment is the same as the configuration of the air purification system according to Embodiment <NUM>, and the same reference signs are given to the same constituent elements and detailed descriptions thereof are omitted. In the present embodiment, air purification system <NUM> according to Embodiment <NUM> is referred to as main body 1a.

<FIG> is a block diagram illustrating air purification system 2a according to Embodiment <NUM> which further includes, for example, flow control valve <NUM> having a flow meter. <FIG> is a schematic diagram illustrating main body 1a of air purification system 2a according to Embodiment <NUM>.

As illustrated in <FIG> and <FIG>, air purification system 2a includes main body 1a, second filter unit <NUM>, heater <NUM>, third filter unit <NUM>, and first detector 105a.

Main body 1a includes plasma reactor 3a and first filter unit 60a.

Plasma reactor 3a includes spectroscope <NUM> and third dielectric <NUM>, as well as first housing <NUM>, linear electrode <NUM>, electric field probe <NUM>, actuator <NUM>, power feeding terminal <NUM>, and power feeding line <NUM>. Note that plasma reactor 3a may selectively include one or more of the following constituent elements: frequency changing oscillator + modulator <NUM>, first amplifier <NUM>, second amplifier <NUM>, second amplifier <NUM>, cymoscope <NUM>, voltage converter <NUM>, controller <NUM>, and duct <NUM>.

Note that in the present embodiment, air purification system 2a includes, instead of the first amplifier of Embodiment <NUM>, first amplifier <NUM> and second amplifier <NUM>. First amplifier <NUM> is, for example, an operational amplifier that converts impedance, and second amplifier <NUM> is, for example, a power amplifier. First amplifier <NUM> and second amplifier <NUM> are included in the configuration of power feeder <NUM>.

Spectroscope <NUM> is disposed on the inlet 12a side of first housing <NUM>. Specifically, spectroscope <NUM> is fixed to the outer surface of first housing <NUM>, on the inlet 12a side of first housing <NUM>. Spectroscope <NUM> detects the emission intensity of plasma in plasma generation region P. Note that spectroscope <NUM> may output the detection result to controller <NUM>, and controller <NUM> may adjust the frequency (frequency changing oscillator + modulator <NUM>) and the position of the power feeding point (the output voltage of the voltage converter) according to the detection result.

Third dielectric <NUM> is disposed in space 10a of first housing <NUM>. Specifically, third dielectric <NUM> is disposed in the vicinity of inlet 12a to surround or interpose inlet 12a of first housing <NUM>. Third dielectric <NUM> is disposed also in the vicinity of second dielectric <NUM> disposed at one end of linear electrode <NUM>. Third dielectric <NUM> is a dielectric material that is highly resistant to heat. Third dielectric <NUM> is, for example, ceramic such as quartz glass or alumina.

First filter unit 60a includes second housing <NUM>, first filter <NUM>, second filter <NUM>, fan <NUM>, and flow control valve <NUM> having a flow meter. Note that first filter unit 60a may include duct <NUM>. Although activated carbon is used for first filter <NUM> in the present embodiment, ammonia may be used instead of activated carbon to catalytically decompose nitrogen oxides.

Flow control valve <NUM> having a flow meter is disposed between fan <NUM> and first filter <NUM>. That is to say, flow control valve <NUM> having a flow meter measures and controls the flow rate of the air that flows from first filter <NUM> to fan <NUM> and has passed through first filter <NUM>.

Before the air is taken in as outside air through inlet 12a of first housing <NUM> included in plasma reactor 3a, second filter unit <NUM> filters such air. That is to say, second filter unit <NUM> is an air filter disposed upstream of plasma reactor 3a. Second filter unit <NUM> removes suspended particulates contained in the air before taken into plasma reactor 3a. Suspended particulates include not only bacteria and viruses but also particulates such as dust, pollen, mites, and smoke. Second filter unit <NUM> is, for example, activated carbon, a photocatalyst, a high efficiency particulate air (HEPA) filter, an ultra low penetration air (ULPA) filter, a medium efficiency particulate air (MEPA) filter, etc. The air which has passed through second filter unit <NUM> and from which suspended particulates have been removed, flows into heater <NUM>.

By adjusting the amount of moisture contained in the air that has passed through second filter unit <NUM>, heater <NUM> adjusts the amount of moisture (humidity) of the air flowing into plasma reactor 3a of main body 1a. Heater <NUM> includes a humidity control heater for adjusting the humidity of the air that passes through heater <NUM> and a mist separator that separates, from the air, moisture contained in the air. The air which has passed through heater <NUM> and whose humidity has been adjusted flows into plasma reactor 3a.

Plasma reactor 3a decomposes bacteria, viruses, etc. contained in the air that has flowed into plasma reactor 3a from heater <NUM>. The AC power controlled by controller <NUM> is supplied to plasma reactor 3a so that, by plasma, an energy which is intermediate between the dissociation energy of oxygen molecules contained in the air (approximately <NUM> eV) and the dissociation energy of nitrogen molecules (approximately <NUM> eV) is applied to gas molecules and only the oxygen molecules are thereby dissociated. The air that has passed through plasma reactor 3a is filtered by first filter unit 60a and flows into third filter unit <NUM>.

Third filter unit <NUM> filters the air that has passed through plasma reactor 3a and first filter unit 60a. That is to say, third filter unit <NUM> is an air filter disposed downstream of plasma reactor 3a. Third filter unit <NUM> removes dust contained in the air that has passed through plasma reactor 3a. Third filter unit <NUM> is, for example, activated carbon, a photocatalyst, an HEPA filter, a ULPA filter, an MEPA filter, etc. The air which has passed through third filter unit <NUM> and from which dust has been removed (purified air) flows into first detector 105a.

First detector 105a detects and measures the contents of ozone and nitrogen oxides contained in the air that has been generated through plasma generation and purified. First detector 105a outputs, to controller <NUM>, the measurement result of the contents of ozone and nitrogen oxides contained in the purified air. First detector 105a is an example of a detector.

On the basis of the measurement result of the contents of ozone and nitrogen oxides contained in the air measured by first detector 105a, controller <NUM> adjusts the power supplied to linear electrode <NUM> by operating frequency changing oscillator + modulator <NUM> and amplifier <NUM>, in order to perform control to (i) cause the amount of ozone generated due to plasma generation to become constant at all times, and (ii) apply an energy having an intermediate value between the dissociation energy of oxygen molecules and the dissociation energy of nitrogen molecules, at which nitrogen oxides are substantially not generated. This control may be feedback control which includes this operation and adjustment. When the measurement result shows contents of ozone and nitrogen oxides exceeding predetermined values, controller <NUM> performs control to temporarily stop air purification system 2a so as to prevent discharge of the purified air from air purification system 2a.

In order to perform control to cause the amount of ozone to become constant at all times, controller <NUM> performs such operations as follows via frequency changing oscillator + modulator <NUM> on the basis of the measurement result from, for example, first detector 105a: adjustment of the amplitude of the AC power supplied to linear electrode <NUM>; amplitude modulation on the AC power; and adjustment of the amplitude modulation to cause the value of the amplitude modulation to intermittently repeat a given value and zero. This control may be feedback control. For example, controller <NUM> controls the amount of plasma generated, by adjusting the duty cycle of the AC power through amplitude modulation. By doing so, it is possible to control the contents of ozone and nitrogen oxides contained in the purified air.

When controller <NUM> performs amplitude modulation via frequency changing oscillator + modulator <NUM>, the waveform of the AC power supplied to linear electrode <NUM> is a waveform obtained by performing the amplitude modulation on a carrier wave. At this time, controller <NUM> adjusts the power supplied to linear electrode <NUM> via frequency changing oscillator + modulator <NUM>, to perform control to cause the amount of ozone to be, for example, less than or equal to the amount of ozone originally contained in the earth's atmosphere, and preferably, to cause the ozone concentration to be less than or equal to <NUM> ppm. This control may be feedback control.

Advantageous effects of air purification system 2a according to the present embodiment are described.

For example, with conventional air purification systems, it is difficult to control dissociation of nitrogen molecules induced by an intense electric field corresponding to a pulse apex value and to control the nitrogen oxides generated as a result.

In view of this, air purification system 2a according to the present embodiment includes first detector 105a that monitors the amounts of ozone and nitrogen oxides generated. With the amounts of ozone and nitrogen oxides generated set as targets to be controlled, air purification system 2a, for example, adjusts the waveform of the input power, adjusts the amplitude modulation, and adjusts the electric field applied to plasma while maintaining electromagnetic resonance so that an energy at which oxygen molecules are dissociated by plasma and ozone is thereby generated but nitrogen molecules are not dissociated and generation of nitrogen oxides is thereby minimized is inputted to gas molecules. As a result, it is possible to prevent discharge of harmful gas and perform safe and highly efficient air purification. Control corresponding to these adjustments may be feedback control.

As described, in air purification system 2a according to the present embodiment, controller <NUM> obtains from first detector 105a the measurement result of the content of ozone contained in the air that has passed through the region between linear electrode <NUM> and first housing <NUM> (or plasma generation region P), and on the basis of the measurement result obtained, adjusts the power supplied, for controlling the air passing through the region between linear electrode <NUM> and first housing <NUM> to (i) cause the amount of ozone generated due to plasma generation to become constant at all times, and (ii) apply an energy having an intermediate value between the dissociation energy of oxygen molecules and the dissociation energy of nitrogen molecules, at which nitrogen oxides are substantially not generated. This adjustment may be feedback control.

With this, plasma reactor 3a can efficiently generate the minimum ozone necessary for decomposition of viruses, cause the concentration of ozone contained in the purified air to be a concentration harmless to the human body and so on, kill the bacteria and viruses contained in the air, and easily remove the generated ozone using filter <NUM>.

In air purification system 2a according to the present embodiment, the power supplied to linear electrode <NUM> is AC power. Controller <NUM> performs control to cause the amount of ozone generated to become constant at all times. Controller <NUM> adjusts the amplitude of the AC power supplied, so as to cause the amount of ozone generated to be less than or equal to the amount of ozone originally contained in the earth's atmosphere, for example. This control may be feedback control.

In this case, too, it is possible to cause the concentration of ozone contained in the purified air to be a concentration harmless to the human body and so on; for example, cause the amount of ozone to be less than or equal to the amount of ozone originally contained in the earth's atmosphere, and it is also possible to kill the bacteria and viruses contained in the air and easily remove the generated ozone using filter <NUM>.

In air purification system 2a according to the present embodiment, the waveform of the AC power supplied to linear electrode <NUM> is a waveform obtained by performing amplitude modulation on a carrier wave. Controller <NUM> performs control by adjusting the amplitude modulation to cause the amount of ozone generated to become constant; for example, cause the amount of ozone generated to be less than or equal to the amount of ozone originally contained in the earth's atmosphere. This control may be feedback control.

In air purification system 2a according to the present embodiment, the waveform of the AC power supplied to linear electrode <NUM> is a waveform obtained by performing amplitude modulation on a carrier wave. Controller <NUM> performs control to cause the amount of ozone generated to become constant. For example, in order to perform control to cause the amount of ozone to be less than or equal to the amount of ozone originally contained in the earth's atmosphere, the time interval is adjusted to cause the value of the amplitude modulation to intermittently repeat a given value and zero. This control may be feedback control.

In this case, too, it is possible to cause the concentration of ozone contained in the purified air to be a concentration harmless to the human body and so on; for example, to cause the amount of ozone to be less than or equal to the amount of ozone originally contained in the earth's atmosphere, and it is also possible to kill the bacteria and viruses contained in the air and easily remove the generated ozone using filter <NUM>.

Also, in air purification system 2a according to the present embodiment, controller <NUM> adjusts the power supplied, for the purpose of performing control to cause the ozone concentration to be less than or equal to <NUM> ppm. This control may be feedback control.

Also, air purification system 2a according to the present embodiment generates plasma using a high voltage having a continuous wave of a frequency in a range of from <NUM> to <NUM> obtained by performing frequency modulation.

In air purification system 2a, the Q factor becomes <NUM> or greater, and thus, the inputted high-frequency voltage can be boosted precisely by <NUM> times or more. In this case, since the power is supplied from first amplifier <NUM> to linear electrode <NUM> of air purification system 2a at a power efficiency greater than or equal to <NUM>%, the power efficiency is substantially <NUM>%. When a high voltage having a high frequency in a range of from <NUM> to <NUM> is supplied to linear electrode <NUM>, the oscillation amplitude of electrons in first housing <NUM> is not so great and the speed of the electrons is in a limited range, and therefore, high-density plasma can be generated.

For example, the dissociation energy of nitrogen molecules is approximately <NUM> eV, the dissociation energy of oxygen molecules is approximately <NUM> eV, and the envelope breakdown energy of, for example, viruses contained in the air is approximately <NUM> eV or less. In air purification system 2a, an energy of approximately <NUM> eV or greater is applied to gas molecules so that ozone is efficiently generated by dissociating oxygen molecules while inhibiting generation of nitrogen oxides. This allows not only direct attack, i.e., inelastic collision, of ionized ions, electrons, and radicals on viruses, but also: decomposition of the viruses by efficiently generating ozone through dissociation of oxygen molecules; and inhibition of generation of harmful nitrogen oxides. In the present invention, feedback control is performed on a change in the resonance state caused by a change in the plasma state and the type and amount of gas molecules flowing in, so as to maintain the electromagnetic resonance state at all times by adjusting the frequency of the input power and the position of the power feeding point. By doing so, it is possible to maintain high "power-virus" decomposition efficiency. Furthermore, by adjusting the intensity (may be the average intensity) of the input power, e.g., the waveform or amplitude of the input power in the resonance state, control can be performed to cause the concentration of ozone contained in the air that is eventually discharged from the air purifier for human breathing, to be less than or equal to <NUM> ppm or about the concentration of ozone originally contained in the earth's atmosphere, while efficiently generating the minimum ozone necessary for decomposition of viruses. Control corresponding to this series of adjustments may be feedback control.

Ozone at a concentration less than or equal to <NUM> ppm can be removed by filter <NUM>, for example. The result of detection by first detector 105a is fed back to controller <NUM> to apply, to gas molecules inputted to plasma reactor 3a, an energy that is greater than equal to the dissociation energy of oxygen and less than or equal to the dissociation energy of nitrogen, or an energy equivalent to the dissociation energy of oxygen. Thus, it is possible to supply, as purified air necessary for human breathing, purified air in which the generation of nitrogen oxides is inhibited while the minimum amount of ozone necessary for decomposition of bacteria, viruses, etc. is generated.

Supply of a high voltage having a high frequency to linear electrode <NUM> results in application of an energy which exceeds the dissociation energy of nitrogen molecules contained in the gas inputted to plasma reactor 3a. This causes generation of nitrogen oxides due to nitrogen molecules contained in the air and generation of excessive ozone for the purpose of decomposing viruses. By controlling the plasma generation (By controller <NUM> controlling the high-frequency AC power supplied to linear electrode <NUM>) to cause no generation of nitrogen oxides and cause the concentration of ozone contained in the purified air to be a concentration harmless to the human body and so on (e.g., <NUM> ppm), it is possible to kill bacteria and viruses contained in the air using the minimum amount of ozone necessary, and easily remove excess ozone using filter <NUM>.

<FIG> is a block diagram illustrating air purification system 2b according to Variation <NUM> of Embodiment <NUM> which includes second filter unit <NUM>, heater <NUM>, second detector 105b, first filter unit 60a, first detector 105a, and pipe 17a. In <FIG>, the flow of air, as outside air, is illustrated by solid arrows, and the flow of signals such as a measurement result is illustrated by dashed arrows.

Air purification system 2b according to the present variation is different from the air purification system according to Embodiment <NUM> in that, for example, main body 1b includes controller <NUM>.

Air purification system 2b according to Variation <NUM> of Embodiment <NUM> includes main body 1b, second filter unit <NUM>, heater <NUM>, second detector 105b, first filter unit 60a, and first detector 105a. In the present variation, air purification system 2b does not include the third filter unit included in Embodiment <NUM>. In the present variation, first filter unit 60a is used instead of the third filter unit included in Embodiment <NUM>.

Main body 1b includes plasma reactor 3b and controller <NUM>. In the present embodiment, main body 1b does not include first filter unit 60a. First filter unit 60a is disposed downstream of plasma reactor 3b because the air that has passed through plasma reactor 3b flows into first filter unit 60a. Note that although main body 1b includes frequency changing oscillator + modulator <NUM>, first amplifier <NUM>, second amplifier <NUM>, second amplifier <NUM>, cymoscope <NUM>, voltage converter <NUM>, duct <NUM>, second housing <NUM>, filter <NUM>, fan <NUM>, and so on illustrated in <FIG>, the configuration is simplified in <FIG>.

Plasma reactor 3b includes first housing <NUM>, linear electrode <NUM>, power feeder <NUM>, electric field probe <NUM>, actuator <NUM>, spectroscope <NUM>, third dielectric <NUM>, first amplifier <NUM>, second amplifier <NUM>, second amplifier <NUM>, cymoscope <NUM>, and voltage converter <NUM>.

Second detector 105b is disposed between plasma reactor 3b and first filter unit 60a. The air that has passed through plasma reactor 3b passes through second detector 105b. Second detector 105b detects and measures the contents of ozone and nitrogen oxides contained in a gas which has been purified by plasma and in which bacteria, viruses, etc. have been decomposed by plasma. As with first detector 105a, second detector 105b also outputs, to controller <NUM>, the measurement result of the contents of ozone and nitrogen oxides contained in the purified air. Second detector 105b may also be an example of the detector.

Using the measurement result of second detector 105b as the control target, controller <NUM> adjusts the AC power supplied from power feeder <NUM> to linear electrode <NUM> of plasma reactor 3b. This adjustment may be feedback control. When the measurement result shows contents of ozone and nitrogen oxides exceeding predetermined values, controller <NUM> adjusts the AC power supplied to linear electrode <NUM>, to inhibit generation of ozone and nitrogen oxides. This adjustment may be feedback control.

Air purification system 2b according to the present variation includes pipe 17a that returns the air that has passed through second detector 105b, to plasma reactor 3b. For example, pipe 17a makes connection from the outlet side to the inlet 12a side of first housing <NUM> included in plasma reactor 3b. In the present embodiment, pipe 17a makes connection from a duct connecting second detector 105b and first filter unit 60a to a duct connecting heater <NUM> and plasma reactor 3b. Pipe 17a returns part of the air that has passed through first housing <NUM>, to the inlet 12a side of first housing <NUM> for circulation. Note that pipe 17a may be provided with a fan or the like to return the air to plasma reactor 3b.

The purified gas that has passed through first filter unit 60a passes through first detector 105a.

Such air purification system 2b according to the present variation includes pipe 17a which returns, to the inlet 12a side, part of the air that has been taken in through inlet 12a and has passed through the inside of first housing <NUM> (plasma reactor 3b).

According to this, by returning part of the air that has passed through first housing <NUM>, to the inlet 12a side, it is possible to ensure again that suspended matter such as bacteria and viruses is decomposed. The above-described circulation of part of the air that has passed through first housing <NUM> enables further purification of the air.

<FIG> is a block diagram illustrating air purification system 2c according to Variation <NUM> of Embodiment <NUM> which includes second filter unit <NUM>, heater <NUM>, second detector 105b, pipe 17a, first filter unit 60a, and first detector 105a, and in which second detector 105b is provided to pipe 17a.

Air purification system 2c according to the present variation is different from the air purification system according to Variation <NUM> of Embodiment <NUM> in that second detector 105b is provided on pipe 17a.

As illustrated in <FIG>, pipe 17a makes connection from a duct connecting plasma reactor 3b and first filter unit 60a to a duct connecting heater <NUM> and plasma reactor 3b. Second detector 105b is disposed on pipe 17a. Note that although main body 1b includes frequency changing oscillator + modulator <NUM>, first amplifier <NUM>, second amplifier <NUM>, second amplifier <NUM>, cymoscope <NUM>, voltage converter <NUM>, duct <NUM>, second housing <NUM>, filter <NUM>, fan <NUM>, and so on illustrated in <FIG>, the configuration is simplified in <FIG>.

First filter unit 60a is connected to plasma reactor 3b and filters the air that has passed through plasma reactor 3b.

In air purification system 2c, controller <NUM> adjusts the intensity or waveform (the average intensity) of the power inputted to the plasma reactor, for the purpose of applying, to molecules (e.g., O<NUM>, N<NUM>) contained in the air taken into air purification system 2c, an energy that is less than or equal to the dissociation energy of N<NUM> (e.g., approximately <NUM> eV) and is in the vicinity of the dissociation energy of O<NUM> (e.g., approximately <NUM> eV), in order to prevent generation of nitrogen oxides that are harmful to the human body. This adjustment may be feedback control. Controller <NUM> performs control to cause the output of second detector 105b disposed inside or outside plasma reactor 3b to be an amount of generated ozone of <NUM> ppm or less, for example.

As described, in the present variation, controller <NUM> adjusts the input power inputted to plasma reactor 3b, for the purpose of applying, to a gas taken into plasma reactor 3b, an energy that is greater than or equal to the dissociation energy of oxygen molecules contained in the air taken in through inlet 12a and is less than or equal to the dissociation energy of nitrogen molecules. This adjustment may be feedback control.

<FIG> is a block diagram illustrating air purification system 2e according to Variation <NUM> of Embodiment <NUM> which includes second filter unit <NUM>, heater <NUM>, and first detector 105a, and in which main body 1c including controller <NUM> and so on is used.

Air purification system 2e according to the present variation is different from the air purification system according to Variation <NUM> of Embodiment <NUM> in that the second detector and the pipe are not included and that main body 1c includes first filter unit 60a.

As illustrated in <FIG>, main body 1c according to the present variation includes plasma reactor 3b, first filter unit 60a, and controller <NUM>. Note that although main body 1c includes frequency changing oscillator + modulator <NUM>, first amplifier <NUM>, second amplifier <NUM>, second amplifier <NUM>, cymoscope <NUM>, voltage converter <NUM>, duct <NUM>, second housing <NUM>, filter <NUM>, fan <NUM>, and so on illustrated in <FIG>, the configuration is simplified in <FIG>.

<FIG> is a block diagram illustrating air purification system 2f according to Variation <NUM> of Embodiment <NUM> which includes second filter unit <NUM>, heater <NUM>, and first detector 105a.

Air purification system 2f according to the present variation is different from the air purification system according to Variation <NUM> of Embodiment <NUM> in that main body 1a illustrated in <FIG> is used.

As illustrated in <FIG>, main body 1a includes plasma reactor 3a and first filter unit 60a. Plasma reactor 3a includes first housing <NUM>, linear electrode <NUM>, power feeder <NUM>, actuator <NUM>, spectroscope <NUM>, third dielectric <NUM>, electric field probe <NUM>, second amplifier <NUM>, cymoscope <NUM>, voltage converter <NUM>, controller <NUM>, and so on illustrated in <FIG>.

<FIG> is a block diagram illustrating air purification system <NUM> according to Variation <NUM> of Embodiment <NUM> which includes second filter unit <NUM> and first detector 105a.

Air purification system <NUM> according to the present variation is different from the air purification system according to Variation <NUM> of Embodiment <NUM> in that the heater is not included.

As illustrated in <FIG>, second filter unit <NUM> is connected to main body 1a, and the air that has passed through second filter unit <NUM> is taken into plasma reactor 3b of main body 1a.

<FIG> is a block diagram illustrating air purification system <NUM> according to Variation <NUM> of Embodiment <NUM> which includes first detector 105a.

Air purification system <NUM> according to the present variation is different from the air purification system according to Variation <NUM> of Embodiment <NUM> in that the second filter unit is not included.

As illustrated in <FIG>, plasma reactor 3b of main body 1a directly takes in the air, which is outside air in the surrounding environment.

Protective clothing <NUM> according to the present embodiment is described.

The present embodiment is different from Embodiment <NUM> in that it relates to protective clothing <NUM> that includes air purification system <NUM>. A configuration of air purification system <NUM> according to the present embodiment is the same as the configuration of the air purification system according to Embodiment <NUM>, and the same reference signs are given to the same constituent elements and detailed descriptions thereof are omitted.

<FIG> is a schematic diagram illustrating a front view of protective clothing <NUM> according to Embodiment <NUM> and display 201d of protective clothing <NUM>. <FIG> is a side view of protective clothing <NUM> according to Embodiment <NUM> viewed from a lateral side.

As illustrated in <FIG> and <FIG>, protective clothing <NUM> includes air purification system <NUM>, covering body <NUM>, and display 201d.

Air purification system <NUM> purifies the air taken in from the outside and supplies the purified air into covering body <NUM>. That is to say, air purification system <NUM> purifies the air by decomposing and removing bacteria, viruses, etc. contained in the air, and supplies the purified air into covering body <NUM>.

Covering body <NUM> is provided with air purification system <NUM> and covers the surface of the body of a person. Covering body <NUM> is capable of covering the entire body of a person and maintaining the inside sealed. Covering body <NUM> includes: outer cover 201x that covers the head, upper limb, body trunk, and lower limb of the person wearing covering body <NUM>; helmet 201a to be worn over outer cover 201x to protect the head; gloves 201b that protect both hands; and boots 201c that protect both feet. Outer cover 201x and helmet 201a are joined by a joining component such as a joint. Outer cover 201x and gloves 201b are joined by another joining component. Outer cover 201x and boots 201c are joined by yet another joining component.

On the rear side of covering body <NUM>, casing <NUM> that accommodates air purification system <NUM> is attached. Casing <NUM> is an exterior cover of air purification system <NUM>. Casing <NUM> may be included in the configuration of protective clothing <NUM>, and may be included in the configuration of air purification system <NUM>.

<FIG> is a front view of air purification system <NUM> included in protective clothing <NUM> according to Embodiment <NUM>, illustrating how air purification system <NUM> takes in viruses etc. along with the air. <FIG> is a cross-sectional view of air purification system <NUM> included in protective clothing <NUM> according to Embodiment <NUM> along line XVI-XVI in <FIG>. The arrows in <FIG> represent intake and discharge of the air.

As illustrated in <FIG> and <FIG>, air purification system <NUM> takes in the ambient air through a plurality of inlets 12a formed on the rear side of casing <NUM> (the side opposite to the side where covering body <NUM> is provided). The air taken in is purified by air purification system <NUM> and supplied into protective clothing <NUM> through supply pipe <NUM>. In addition, air purification system <NUM> discharges, through a plurality of outlets <NUM> formed on the rear side of casing <NUM>, the air taken into covering body <NUM>. The air in protective clothing <NUM> is discharged outside protective clothing <NUM> through supply pipe <NUM>. With protective clothing <NUM>, the air purified through air purification system <NUM> is supplied into protective clothing <NUM>, and the air that a person breathed inside protective clothing <NUM> is discharged outside protective clothing <NUM>. The supply of the purified air into protective clothing <NUM> and the discharge of the air are performed using a micro-pump unit, for example. In other words, the purified air is supplied and discharged so that the person can breathe inside protective clothing <NUM>. Note that a carbon dioxide absorber capable of processing carbon dioxide discharged by a person through breathing may be provided inside casing <NUM>.

In the present embodiment, the plurality of inlets 12a and the plurality of outlets <NUM> formed on the rear side of casing <NUM> are alternately arranged one by one. Note that the arrangement of inlets 12a and outlets <NUM> is not limited to the arrangement according to the present embodiment, and they may be alternately arranged two or more by two or more, for example.

Display 201d is a monitor attached to the front side of covering body <NUM>. Display 201d displays information regarding the inside of covering body <NUM>, for example. The information indicates, for example, the level of the purified air inside covering body <NUM>, the temperature and humidity inside covering body <NUM>, and the remaining battery level, etc. Display 201d displays the information by being controlled by controller <NUM> of air purification system <NUM>.

Advantageous effects of protective clothing <NUM> according to the present embodiment are described.

As described above, protective clothing <NUM> according to the present embodiment includes air purification system <NUM> and covering body <NUM> that is provided with air purification system <NUM> and that covers the surface of the body of a person. Air purification system <NUM> purifies the air taken in from the outside and supplies the purified air into covering body <NUM>.

This allows the person to act safely even in an environment where bacteria, viruses, etc. are suspended in the air.

In addition, protective clothing <NUM> also yields the same advantageous effects as those of Embodiment <NUM> etc. described above.

Although the present disclosure has been described above based on Embodiments <NUM> to <NUM>, the present disclosure is not limited to Embodiments <NUM> to <NUM>.

For example, the air purification system and the protective clothing including the air purification system according to Embodiments <NUM> to <NUM> are designed to increase the Q factors of the resonators of the linear electrode and the first housing. The Q factor of the resonance is determined by the ratio between the resistance of the linear electrode and the resistance of the power feeding line (input power loss).

For example, the air purification system according to Embodiment <NUM> may include the plasma reactor and the first filter unit as illustrated in <FIG>.

The present disclosure also encompasses other forms achieved by making various modifications conceivable to those skilled in the art to Embodiments <NUM> to <NUM>, as well as forms implemented by freely combining constituent elements and functions of Embodiments <NUM> to <NUM>.

It remains, that the scope of the invention is defined by the claims.

Claim 1:
An air purification system (<NUM>) that generates plasma using voltage,
the air purification system comprising:
a first linear electrode (<NUM>) that is configured to generate electromagnetic resonance when power is supplied;
a second electrode (<NUM>) disposed surrounding the first electrode in a state of being separated from the first electrode, and comprising an inlet (12a);
a power feeder (<NUM>) that is configured to supply power to the first electrode;
an electric field probe (<NUM>) that is configured to measure an intensity of an electric field between the first electrode and the second electrode; and
a controller (<NUM>) that is configured to control the power supplied to the first electrode,
characterised in that the controller is configured to perform control by adjusting a frequency of the power supplied to the first electrode and a position at which the power is supplied to the first electrode, to cause a half wavelength during the electromagnetic resonance in the second electrode (<NUM>) to be a sum of the length of the first linear electrode (<NUM>) in the longitudinal direction and the length of plasma generated in the same longitudinal direction between one end of the first linear electrode and the inlet (12a), and
maximize an output value of a signal indicating the intensity of the electric field measured by the electric field probe.