JP2003340454A - Plasma sterilizer and plasma sterilized refreshing water device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma sterilized refreshing water device which is low in impressed voltage, is safe and is mechanically simple. <P>SOLUTION: Coaxial electrodes 2 and 3 are installed in water and the size of the circular core-like electrode 3 on the inner side is made extremely smaller than the size of the cylindrical electrode 2 on the outer side. A power source 1 is connected between the electrodes 2 and 3 to enhance insulation characteristics between the electrodes 2 and 3 and to generate an electric discharge 4 between the electrodes 2 and 3 by a low voltage. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma sterilization device and a plasma sterilization cooler.

[0002]

2. Description of the Related Art Conventionally, the technologies disclosed in the following technical fields have been disclosed.

(1) A sterilizer using a high voltage pulse (see, for example, Japanese Patent Laid-Open No. 63-82666) uses a coaxial cylindrical tube and a pulse generator, but it is dangerous because a voltage of 20 kV needs to be applied. In addition, it is considered that a large amount of ozone is generated. Therefore, it can be said that sterilization also has a large proportion of ozone.

(2) Wastewater treatment device (Japanese Patent Laid-Open No. 2001-25
No. 2665), a protrusion is attached to an electrode inside a coaxial cylinder to perform pulse discharge. The discharge voltage is 50 kV, and it is considered that a large amount of ozone is generated as in (1) above.

(3) In addition to this, there is a method in which an electric field in water is strengthened by covering the electrodes with an insulating material to cause electric discharge, but the insulating material may be dissolved by the electric discharge, and it is used in the discharging part for drinking water. That is not the right thing to do.

[0006]

As described above, each of the conventional sterilizers has a problem and is not technically satisfactory.

In view of the above situation, it is an object of the present invention to provide a plasma sterilizer and a plasma sterilizer / cooler which have a low applied voltage, are safe, and have a simple structure.

[0008]

In order to achieve the above object, the present invention provides [1] a plasma sterilizer in which a coaxial electrode is installed in water, and a circular core inside the outer cylindrical electrode has a size smaller than that of the outer cylindrical electrode. It is characterized in that the size of the electrode is extremely small, a power source is connected between the electrodes to enhance the insulation between the electrodes, and a discharge is generated between the electrodes at a low voltage.

[2] The plasma sterilizer according to the above [1] is characterized in that the power source comprises a dry battery (3 V) and an igniter.

[3] In the plasma sterilizer according to the above [1], a hole is formed in the side surface of the outer cylindrical electrode to allow water to flow into the inside, and an electric field is generated between the hole and the inner circular core electrode. It is characterized in that it concentrates on the periphery to enhance the electric field strength and enhance the efficiency of the discharge path to water.

[4] In the plasma sterilizer according to the above [1], a high-voltage impulse voltage of short wavelength is applied between the electrodes.

[5] In the plasma sterilizer according to the above [1], brush-like plasma is generated between the electrodes, and ultraviolet rays or high-energy electrons generated by the discharge sterilize the water. .

[6] In a plasma sterilizer-cooled water cooler, coaxial electrodes are installed in water, the size of the inner circular core electrode is made extremely smaller than the size of the outer cylindrical electrode, and a power source is provided between the electrodes. It is characterized in that fresh air is added to sterilized water in addition to a water purifying unit that connects the electrodes to enhance insulation between the electrodes and causes discharge between the electrodes at a low voltage.

As described above, 1. Since the coaxial electrode is installed in water and the size of the inner circular core electrode is made extremely smaller than the size of the outer cylindrical electrode, the insulation between the electrodes is increased and the voltage between the electrodes is reduced at a low voltage. A discharge can be generated.

2. Since it can be discharged at a low voltage, the power source can be composed of only a dry battery (3V) and an igniter, and can be commercialized for portable use.

3. Since the coaxial cylindrical electrode and the circular core electrode are used as the electrodes, the electric field can be strengthened by the cylindrical effect.

4. The structure in which a hole is formed on the side surface of the outer cylindrical electrode to make the water inflow (outlet) port concentrate the electric field around the hole and the inner circular core electrode, strengthening the electric field strength and making the discharge path The efficiency can be increased.

5. A high-voltage impulse voltage of short wavelength is applied between the electrodes. With this system, a pulsed high electric field is generated between the electrodes, an intense underwater discharge is generated, and a brush-like plasma is generated between the electrodes. Ultraviolet rays and high-energy electrons generated by this discharge can sterilize the water.

6. By adding fresh air to sterilized water, you can make delicious drinking water.

7. The discharge voltage is lowered (2-3 kV) by forming a water inlet hole on the side surface of the outer cylindrical electrode and making the inner circular core electrode much smaller than the outer cylindrical electrode. be able to.

8. Since the voltage is low, ozone generation is suppressed.

9. Since the electrodes are not covered with the insulator, the insulator is not dissolved by the discharge.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below.

FIG. 1 is a schematic diagram of a discharge device of a plasma sterilizer showing an embodiment of the present invention, and FIG. 2 is a diagram (substitute photograph) showing a streamer-like plasma by the discharge device.

In these figures, 1 is a power source, 2 is a coaxial cylindrical electrode having a large diameter arranged outside, and 3 is a circular core electrode having a small diameter arranged inside the coaxial cylindrical electrode 2 (for example, , A rod-shaped electrode, a cylindrical electrode, a cylindrical electrode, etc.), 4 is a brush-shaped plasma (discharge), 5 is water to be supplied, 6 is arranged outside the coaxial cylindrical electrode 2, and a brush-shaped plasma (discharge) ) 4 is a coaxial cylindrical tube for introducing water 5 and 7 is a hole formed on the side surface of the coaxial cylindrical electrode 2 in the vicinity of the circular core electrode 3.

As shown in FIG. 1, the voltage of a 1.5 V dry battery is converted into a high voltage by an igniter to be a power source 1 for discharging, and the high voltage from the power source 1 is used as a coaxial cylindrical electrode 2 and a circular core electrode. 3 is applied. As a result, a brush discharge 4 is generated between the cylindrical electrode 2 and the circular core electrode 3 together with the spark discharge.

Here, the features of the discharge device of the plasma sterilizer will be described. The discharge device is composed of a coaxial cylindrical electrode 2 and a circular core electrode 3, and the inner circular shape with respect to the size of the outer coaxial cylindrical electrode 2. The size of the core electrode 3 is extremely small. The reason for this is to enhance the insulation between the coaxial cylindrical electrode 2 and the circular core electrode 3. For example, the coaxial cylindrical electrode 2
Is a stainless steel tube having an inner diameter of 1.8 mm and a length of 10 mm, and the circular core electrode 3 is a stainless steel rod having a diameter of 1 mm and a length of 1 mm.

The supplied water 5 flows into the circular core electrode 3 through a hole 7 formed in the side surface of the coaxial cylindrical electrode 2 near the circular core electrode 3. Since lines of electric force are concentrated around the hole 7, discharge easily occurs in a region where water flows.

The coaxial cylindrical tube 6 is an insulator (acrylic) and supports the coaxial cylindrical electrode 2 and blocks the water 5. The voltage waveform of the power supply 1 is a half sine wave pulse (voltage 2-3
kV), or a dry battery (3V) and an igniter are used. The frequency is determined according to the flow velocity.

By the electric discharge, the water 5 is decomposed into hydrogen and oxygen by electrolysis between the electrodes 2 and 3, and many bubbles are generated by the electric force. Since the air bubbles (air) contain dirty components, water 5 can be sterilized by performing air bubble discharge.

The principle of the plasma sterilizer of the present invention will be described below.

FIG. 3 is a diagram showing a discharge state and a discharge voltage waveform generated between the electrodes of the plasma sterilization apparatus of the present invention. FIG. 3 (a) shows a discharge state generated between the electrodes.
(B) shows the waveform of the discharge voltage. Note that FIG.
In (b), the frequency is 8 Hz.

As shown in FIG. 3 (a), a spark discharge 4a that directly causes a discharge and a bubble discharge 4b that discharges in bubbles are generated between the outer coaxial cylindrical electrode 2 and the inner circular core electrode 3. It As shown in FIG. 3B (not shown), the discharge waveform uses impulse.

FIG. 4 shows a state in which electric discharge occurs through the bubbles 8 generated by the electric discharge (because the inlet of the water 5 through the hole 7 becomes a strong electric field, the electric bubbles 8 are generated in this portion).

By using such an inflow mechanism of the water 5, the discharge effect on the water 5 can be improved.

Next, a plasma sterilization water cooler showing an embodiment of the present invention will be described.

Conventionally, since a large amount of chlorine is injected and heat treatment is carried out by boiling in order to sterilize general bacteria, Escherichia coli, and mold, "umami" as drinking water disappears due to chlorine and high temperature.

FIG. 5 is a schematic diagram of a plasma sterilization cooler showing an embodiment of the present invention.

In this figure, 100 is a water cooler and 10
1 is a water purification unit, 102 is a waste removal unit, 103 is an air mixing unit, 104 is a cool air cylinder, 105 is a discharge power source, 1
Reference numeral 06 is tap water, 107 is treated fresh water, and 108 is a sterilized air exhaust port.

The plasma sterilization cooler of the present invention is as follows.
In the water purifying section 101, air bubbles of dirty air dissolved in the tap water 106 are generated by pressure fluctuation due to electric discharge,
Performs bubble sterilization by streamer discharge. Next, the accelerated electrons dissociate chlorine from water molecules.

In the air mixing section 103, the cool air cylinder 1
The fresh air from 04 is melted in and can be obtained as the fresh water 107.

The above process is included.

A plurality of discharge devices shown in FIG. 1 are installed in the water purification section 101 according to the size of the water cooler.

When an igniter is used as a power source, a portable water purifier having a sterilizing effect can be manufactured, and drinking water can be obtained anywhere with one dry battery.

Next, the sterilizing effect of underwater plasma will be described.

FIG. 6 shows the bactericidal effect.

Plasma sterilizer (underwater plasma generator) described above (cylindrical electrode: diameter 2 mm, length 10 mm)
Escherichia coli was placed in 9 cc of water in a container equipped with the above, and the sterilization effect by the plasma in the electrode was examined. The water containing E. coli was allowed to flow out of the container through the electrode. Also, the discharge is an igniter (high voltage generator: input voltage 3V,
A frequency of 15 Hz and an output voltage of 10 kV) were used.

FIG. 6 (a) is a view of the bacteria on the petri dish, FIG.
(B) shows the relationship between the number of bacteria and time. Note that FIG.
In (b), N is the number of E. coli and N ₀ is the number of E. coli before discharge (initial value).

As shown in FIG. 6 (b), the Escherichia coli decreased with the discharge time, and almost disappeared in 150 seconds. This is probably because E. coli was killed by the high-energy electrons generated in the plasma.

Next, a first application example of the present invention will be described.

FIG. 7 is a schematic view showing a plasma sterilization apparatus showing a first application example of the present invention, FIG. 7 (a) is a schematic view of the element, and FIG. 7 (b) is a perspective view showing the whole. Is.

As shown in this figure, by attaching a large number of electrodes to a water pipe as a set, tap water in which the air component in the water is discharge sterilized can be obtained.

The boiling sterilization requires a large amount of heat and thus requires a large amount of electric power, but the electric discharge sterilization using the plasma sterilization apparatus of the present invention does not require boiling water and consumes less power. Also, there is no problem of post-processing.

Next, a second application example of the present invention will be described.

FIG. 8 is a block diagram of a plasma sterilizer showing a second application example of the present invention, in which the water injection port 20 of the washing machine 200 is used.
1 is equipped with the discharge device shown in FIG. 1, and the water after air bubbles are discharged from the tap water is injected into the washing machine 200. In addition,
9 is a water pipe.

In this figure, the water from which air bubbles have been removed easily penetrates into the laundry and is effective in removing dirt. Therefore, less detergent is required.

Next, the underwater plasma generation method will be described.

(1) Cylindrical electrode (diameter 2 mm, length 10)
mm) was used to perform the experiment.

The electric field E in the electrode tube and the impedance z between the electrodes are as follows.

1 / z = 1 / R + jωC I = V _d / | z | E = V _d / [rln (b / a)] where V _d is the discharge voltage, I is the interelectrode current, and R is the interelectrode. Resistance, C is the capacitance between the electrodes, a is the radius of the inner electrode, and b is the radius of the outer electrode.

In order to generate an underwater discharge, it is necessary to prevent a short circuit between the electrodes due to water, that is, to increase the insulation between the electrodes (I = 0). Therefore, increase R,
It is sufficient to reduce C.

When the applied discharge voltage is constant and the radius a of the inner electrode is constant, the radius b of the outer electrode increases and the electric field weakens. Therefore, the larger the diameter of the outer electrode (the diameter of the inner electrode is constant: the diameter is 1 mm), the thinner the discharge path of the spark discharge becomes.

The reason why the inner electrode is covered with an insulator is to increase the insulation between the electrodes.

When not covered with an insulator, underwater plasma can be formed by shortening the length of the inner electrode and increasing the resistance between the electrodes.

The bactericidal effect of underwater plasma is shown in FIG.
It is similar to that shown in (b).

Next, the generation of bubbles will be described.

FIG. 9 is a diagram (substituting photograph) showing the generation of bubbles in the plasma sterilizer.

Bubbles are generated even when plasma is generated in water,
Rather, in the case of a high-frequency hot water generator, much more occurs, and the hot water jumps out at the moment the switch is turned on. Since the underwater plasma generates light, the energy is used for light emission, and the thermalization phenomenon hardly occurs. Therefore, underwater plasma is applicable to sterilization in water, dissociation of liquid components, and the like.

The present invention is not limited to the above embodiments, and various modifications can be made based on the spirit of the present invention, and these modifications are not excluded from the scope of the present invention.

[0070]

As described in detail above, according to the present invention, the following effects can be achieved.

(1) Tap water can be sterilized with a small amount of electric power by pulse discharge. Moreover, since no chemicals such as chlorine for disinfection are used, the taste of water is not lost. In addition, good drinking water can be made by dissolving cool air in water.

(2) Since discharge is used, there is no problem in post-treatment.

(3) Since air bubbles in water can be eliminated, the cleaning effect is improved and the amount of detergent can be reduced.

(4) By using an igniter as a power source, a portable sterilizable water purifier can be obtained, and drinking water can be obtained at ease anywhere.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a discharge device of a plasma sterilizer showing an embodiment of the present invention.

FIG. 2 is a diagram showing a streamer-like plasma by a discharge device of a plasma sterilizer showing an embodiment of the present invention (substitute photograph).
Is.

FIG. 3 is a diagram showing a state of discharge occurring between electrodes of a plasma sterilizer of the present invention and a discharge voltage waveform.

FIG. 4 is a diagram showing a state of discharging through bubbles generated by discharging.

FIG. 5 is a schematic view of a plasma sterilization cooler showing an embodiment of the present invention.

FIG. 6 is a diagram showing the sterilizing effect of the plasma sterilization cooler of the present invention.

FIG. 7 is a schematic diagram showing a discharge device of a plasma sterilizer showing a first application example of the present invention.

FIG. 8 is a configuration diagram of a discharge device of a plasma sterilizer showing a second application example of the present invention.

FIG. 9 is a diagram (substitute photograph) showing a bubble generation state of the plasma sterilization apparatus of the present invention.

[Explanation of symbols]

1 power supply 2 Outer coaxial cylindrical electrode 3 Inner circular core electrode 4 Brush-like plasma (discharge) 4a spark discharge 4b Bubble discharge 5 Water supplied 6 coaxial cylindrical tube 7 Holes formed on the side surface of the coaxial cylindrical electrode 8 bubbles 9 water pipes 100 water cooler 101 Water Purification Department 102 Waste removal section 103 Air mixing section 104 cool air cylinder 105 Discharge power supply 106 tap water 107 treated cool water 108 Sterilized air outlet 200 washing machine 201 water inlet

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Claims (6)

[Claims] 1. A coaxial electrode is installed in water, the size of an inner circular core electrode is made extremely smaller than the size of an outer cylindrical electrode, a power source is connected between the electrodes, and insulation between the electrodes is provided. A plasma sterilizer characterized in that the discharge is generated between the electrodes at a low voltage while improving the conductivity. 2. The plasma sterilizer according to claim 1, wherein the power source comprises a dry battery (3V) and an igniter. 3. The plasma sterilizer according to claim 1, wherein a hole is formed in a side surface of the outer cylindrical electrode to allow water to flow into the inside, and an electric field is generated around the hole and the inner circular core electrode. A plasma sterilizer characterized by concentrating and enhancing the electric field strength and increasing the efficiency of the discharge path to water. 4. The plasma sterilizer according to claim 1, wherein a high-voltage impulse voltage having a short wavelength is applied between the electrodes. 5. The plasma sterilizer according to claim 1, wherein a brush-like plasma is generated between the electrodes,
A plasma sterilizer characterized by performing sterilization in water with ultraviolet rays and high-energy electrons generated by this discharge. 6. A coaxial electrode is installed in water, the size of an inner circular core electrode is made extremely smaller than the size of an outer cylindrical electrode, a power source is connected between the electrodes, and insulation between the electrodes is provided. Plasma sterilizer-type water cooler characterized in that fresh air is added to sterilized water in addition to a water purifying section that enhances the property and causes discharge between the electrodes at a low voltage.