JP2003322369A - Method and apparatus for generating minus ion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wet method and apparatus for generating minus ion along with mist capable of generating a larger amount of minus ion while significantly reducing the amount that mist is generated, so that it is comfortably usable not only during the winter when it is dry but also during the summer when humidity is high. <P>SOLUTION: The apparatus includes a water tank 3, a mist outlet 4, a fan 5, and an ultrasonic vibrator 6 mounted in the water tank 3. The driving frequency of the ultrasonic vibrator 6 is set at 2-4.7 MHz and the ultrasonic vibrator generates mist in air inside the water tank 3 while at the same time generating minus ion. <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 wet negative ion generating method and apparatus for generating negative ions by mistifying water by utilizing ultrasonic vibration.

[0002]

2. Description of the Related Art Negative ion generation methods include a discharge method that utilizes a discharge action between a pair of electrodes and a wet method that generates negative ions while mistating water by ultrasonic vibration. In the electric discharge method, since positive ions and ozone are generated at the same time as negative ions, their use is limited.

As a typical example of the wet method, an ultrasonic humidifier capable of generating negative ions has been proposed (Japanese Unexamined Patent Publication No. 200-200200).
1-213155). There, an ultrasonic oscillator is arranged on the inner bottom of the water tank, and the ultrasonic oscillator is driven to mist the water, so that mist for humidification and negative ions are simultaneously generated. The driving frequency of the ultrasonic transducer applied to this type of ultrasonic humidifier is set to 1.6 to 1.7 MHz, and as compared with the case of driving at other frequencies, as shown in FIG. Therefore, a protruding amount of mist can be effectively generated.

[0004]

According to the ultrasonic humidifier that generates negative ions by utilizing the generation of mist as described above, since the mist for humidification and the negative ions can be supplied at the same time, it is easy to dry. Overdrying of the room in winter can be prevented, and the indoor air environment can be optimized by the Leonard effect of negative ions.

However, when used in the summer when the humidity is high, a large amount of mist is emitted before an appropriate amount of negative ions are distributed in the room, so that the humidity in the room becomes abnormally high and comfort is impaired. I will end up. Especially in a highly airtight house, since most outside air does not flow in and out, most of the released mist may cause dew condensation. Although it is easy to remove the moisture by the cooling device, the cooling energy, which should be consumed for cooling the air, is consumed for removing the moisture, which is a waste of energy and has the disadvantage of increasing operating costs. If only the mist generation can be stopped with the ultrasonic humidifier, comfort can be improved even in the summer. However, in the wet method, since negative ions are generated by the agglomeration action of minute droplets in the air as described later, it is theoretically impossible to stop only the generation of mist.

Negative ions are generated in the wet method by utilizing the fact that when minute droplets are agglomerated in air, large droplets are positively charged and small droplets are negatively charged. As far as this is concerned, if a smaller mist is generated, a larger amount of negative ions can be generated.

By the way, the diameter D of the droplet when the mist is generated using the ultrasonic transducer is D≈0.34 (8πT / ρF ² ) ^1/3 (T = surface (Tension, ρ = liquid density, F = ultrasonic transducer drive frequency)
It is known that According to this approximate expression, it can be understood that the driving frequency of the ultrasonic transducer influences the particle diameter D of the droplet, and it can be understood that the droplet diameter decreases as the driving frequency increases. The present inventor has focused on this point and has conducted various tests and experiments aiming to generate a larger amount of negative ions while suppressing the generation amount of mist, and as a result, has proposed the present invention.

An object of the present invention is to produce a larger amount of negative ions while significantly suppressing the generation amount of mist,
Therefore, it is an object of the present invention to provide a method and apparatus for producing negative ions that can be used comfortably not only in the dry season but also in the humid summer season.

The object of the present invention is to produce negative ions and a large amount of mist in the winter when it is easy to dry, and to produce a larger amount of negative ions while significantly suppressing the generation of mist in the summer when the humidity is high. An object of the present invention is to provide a negative ion generating method and a negative ion generating device capable of making the indoor air environment comfortable throughout the year.

An object of the present invention is to provide a negative ion generator capable of reliably preventing the ultrasonic transducer from being driven and broken in a no-load state even if the user forgets to supply water. Especially.

[0011]

The present invention provides a method for producing a negative ion by driving an ultrasonic transducer 6 placed in water to produce a mist in the air facing the water surface and at the same time produce a negative ion, The ultrasonic transducer 6 is driven at a drive frequency of 2 to 4.7 MHz when negative ions are generated. Here, drive frequency is 2 to 4.7
The numerical limitation to MHz is a practical problem because when the driving frequency of the ultrasonic transducer 6 is less than 2 MHz, the amount of mist generated sharply increases and the amount of negative ions generated decreases. On the other hand, the drive frequency of the ultrasonic transducer 6 is
This is because if the frequency exceeds 4.7 MHz, the amount of negative ions produced will be reduced and the amount of mist produced will be extremely reduced.

In the above-mentioned negative ion generating method, the water depth V from the water surface to the vibration surface of the ultrasonic vibrator 6 is 5
It is desirable to set to ~ 36 mm to generate mist and negative ions.

Further, as shown in FIG. 6, an ultrasonic vibrator 28 for generating a mist and an ultrasonic vibrator 6 for generating negative ions are arranged in water, and either one of the ultrasonic vibrators 6 and 28 is arranged. , Or both can be driven so that the amount of mist generated can be selected to be large or small.

The anion generator of the present invention has a water tank 3 for storing water for mist generation, a mist outlet 4 arranged facing the opening surface of the water tank 3, and pressurized air in the inner space of the water tank 3. It is equipped with a blower fan 5 for feeding to the mist outlet 4 via the ultrasonic transducer 6 mounted on the water tank 3, and the driving frequency of the ultrasonic transducer 6 is set to 2 to 4.7 MHz. Thus, at the same time as generating mist in the air in the water tank 3, negative ions are generated.

In the above negative ion generator, it is desirable to set the water depth V from the water surface in the water tank 3 to the vibration surface of the ultrasonic vibrator 6 to 5 to 36 mm.

Further, according to the present invention, as shown in FIG.
An ultrasonic oscillator 28 for generating mist and an ultrasonic oscillator 6 for generating negative ions are respectively arranged in
The ultrasonic oscillator 28 for generating mist is arranged at a position deeper than the ultrasonic oscillator 6 for generating negative ions.
Generally, when drying in the winter or the like, since the ultrasonic vibrator 28 for generating mist is mainly used, the amount of water used increases and can be used to the end if the water is deep. In addition, since the two oscillators have different water levels, when the two oscillators are simultaneously driven, mutual interference of ultrasonic vibrations can be reduced. In this example, the ultrasonic transducer 2 for generating mist
Since the drive frequency of 8 is set to 1.6 to 1.7 MHz, the water level is preferably about 45 mm, and the drive frequency of the ultrasonic transducer 6 for generating negative ions is set to about 3 MHz, so the water level is about 27 mm. It has become.

Further, as shown in FIG. 5, the present invention is provided with a case 20 fixed to the water tank 3 and a lid 21 for sealing the upper surface of the opening of the case 20, and the bottom wall side of the case 20. The ultrasonic oscillator 6 is attached, and the ultrasonic oscillator 6 and the lid 21 are attached.
A liquid for blocking the no-load drive of the ultrasonic transducer 6 may be sealed in the space inside the case between the and.

The water supply tank 2, the water tank 3, the passage 11 connected to the water tank 3, and the mist adhering wall between the water tank 3 and the mist outlet 4 are preferably subjected to antibacterial treatment.

[0019]

In the method and apparatus for producing negative ions of the present invention, the ultrasonic oscillator 6 is driven at a higher drive frequency than the conventional ultrasonic oscillator 6.
To generate negative ions. In particular,
Ultrasonic transducer 6 by specifying the drive frequency to 2 to 4.7 MHz
By driving the, it is possible to generate a larger amount of negative ions while significantly suppressing the generation amount of mist. Therefore, according to the method and apparatus for generating negative ions of the present invention, it is possible to effectively supply negative ions in the winter when it is easy to dry, and even in summer when the humidity is high, the indoor humidity is higher than that. It is possible to release a larger amount of negative ions into the room while avoiding
The Leonard effect can optimize the indoor air environment.

When the water depth V when driving the ultrasonic vibrator 6 is set to 5 to 36 mm to generate mist and negative ions, when the ultrasonic vibrator 6 is driven at the above-mentioned suitable driving frequency, Since mist and negative ions can be generated in a state where the amount of negative ions generated per driving power of the ultrasonic transducer 6 is the largest, the running cost of the ion generator can be reduced.

As shown in FIG. 6, an ultrasonic oscillator 28 for generating a mist and an ultrasonic oscillator 6 for generating negative ions are arranged in water, and either one of the ultrasonic oscillators 6 and 28 is disposed. According to the negative ion generating method and the apparatus for driving both or both of them to select the amount of mist generated, the driving mode of both ultrasonic transducers 6 and 28 can be changed. It is possible to generate mist and negative ions by the operation mode in which generation is suppressed, the operation mode in which a larger amount of mist is generated, and the intermediate operation mode between them, and the indoor air environment can be optimized all year round. For example, in the winter when it is easy to dry, the mist generated by the mist generation ultrasonic vibrator 28 maintains an appropriate humidity and the ultrasonic vibrator 6 that generates negative ions supplies negative ions. In the summer, it is possible to drive only the ultrasonic vibrator 6 that generates negative ions and prevent the increase in humidity.

As shown in FIG. 5, a case 20 fixed to the water tank 3 and a lid 21 for sealing the upper opening are provided, and the ultrasonic transducer 6 and the lid 21 mounted on the bottom wall of the case 20. According to the negative ion generator in which the liquid is sealed in the space in the case between the ultrasonic transducer 6 and the ultrasonic transducer 6 by the liquid sealed in the case 20 even if water is not stored in the water tank 3. Since a drive load can be applied to, even if you forget to replenish water,
It is possible to reliably prevent the ultrasonic vibrator 6 from being driven by the unloaded state and self-destroying.

[0023] If water-contacting portions such as the water tank 2 and the water tank 3 and the mist adhering wall between the water tank 3 and the mist outlet 4 are subjected to antibacterial treatment, germs and mold in the air will propagate. By blocking, the inside of the negative ion generator can be maintained in a sanitary state.

[0024]

(First Embodiment) FIGS. 1 to 5 show an embodiment of an ion generating method and an ion generating apparatus according to the present invention. In the ion generating method of the present invention, as shown in FIG. 1, the ultrasonic transducer 6 arranged in water is driven to generate mist in the air facing the water surface and simultaneously generate negative ions. At that time, set the ultrasonic transducer 6 to 2 to 4.7 MHz
It is characterized in that it is driven at the driving frequency of. Further, it is characterized in that the water depth from the water surface to the vibration surface of the ultrasonic transducer 6 is set to 5 to 36 mm to generate mist and negative ions.

Further, as shown in FIG. 6, an ultrasonic oscillator 28 for generating a mist and an ultrasonic oscillator 6 for producing negative ions are arranged in water, and both ultrasonic oscillators 6 and
One of the features is that one or both of 28 are driven so that the generation amount of mist can be selected to be large or small.

In FIG. 1, the ion generator comprises a hollow main body case 1, a water supply tank 2 which is detachably attached to the main body case 1, and water for mist generation which is incorporated in the main body case 1. Water tank 3 for storing, mist outlet 4 arranged facing the opening surface of water tank 3, blower fan 5 for sending pressurized air to mist outlet 4 via the internal space of water tank 3, and water tank 3 Ultrasonic transducer 6 attached to the
And a drive circuit for the ultrasonic transducer 6 and the like.

The outer shape of the main body case 1 is an L-shape that is long in the left and right, the mist outlet 4 is arranged on the upper surface wall on the upper stage side, and the water supply tank 2 is placed on the upper surface of the tank stand 7 on the lower stage side. ing. A water tap 8 is provided on the lower surface of the water supply tank 2, and the water in the tank is opened by the opening projection 10 provided on the pan 9 to open the water in the tank to the pan 9 and a hose (passage) 11. It can be fed to the water tank 3 via. Code 12
Is a filter. The water level in the water tank 3 is defined by the water tap 8. When the water level drops, the opening of the water tap 8 is exposed to the air, and the water in the tank flows down to restore the water level to the specified water level.

The mist outlet 4 is formed of a tapered conical body, and a flange provided at the base end thereof is rotatably supported by a retaining ring 14 so that the cylindrical tip can be oriented in any direction. . In order to prevent the diffusion of mist and negative ions generated in the gas layer in the water tank 3, a guide cylinder 15 connected to the inner end of the mist outlet 4 is provided in the main body case 1, and the lower end of the guide cylinder 15 closely faces the water surface. It is supposed to do.

The blower fan 5 comprises a centrifugal fan 5a and a motor 5b, and is arranged at the inner bottom of the main body case 1 at the side end on the tank base 7 side. Filter 17 for dust removal
The air taken in through
After being sucked into the inside of a and being pressurized, it blows out from the outlet 18. Since the inside of the main body case 1 is divided into a fan chamber and an air supply chamber by a partition wall 19, the pressurized air blown out from the blowout port 18 bypasses the lower part of the water tank 3 and the peripheral wall to bypass the air inside the water tank 3. After entering the layer portion and further flowing into the guide cylinder 15 through the gap between the lower end of the guide cylinder 15 and the water surface, it is discharged from the mist outlet 4. Due to this air flow, the mist and negative ions generated near the center of the lower surface of the guide cylinder 15 are released into the room.

The ultrasonic vibrator 6 is composed of a disk-shaped vibrating element 6a having electrodes fixed on the front and back sides, and a rubber packing 6b mounted on the outer periphery of the vibrating element 6a, and a guide tube 15 It is arranged on the bottom wall of the water tank 3 facing it, and is fixed by a holder 19. The drive surface of the vibrating element 6a is the water tank 3
Is in contact with water through the opening 16 provided in the bottom wall of the.

By driving the ultrasonic transducer 6, the water surface directly facing the guide tube 15 bulges in a pointed manner, and the mist is separated from the pointed portion by its inertial force. At this time, a part of the mist is negatively charged, or a minute mist that is negatively charged is generated due to the slumping action due to the collision of the mists, and becomes a negative ion. If the water stored in the water tank 3 is hard water or tap water containing a small amount of chlorine, a water filter can be installed at a submerged portion of the water tank 3 to soften the water. Further, the above filter can contain the ion exchange resin and the antibacterial resin to clean the mist generated by the ion generation.

In the anion generator having the above structure, the operating conditions for producing a larger amount of negative ions while suppressing the amount of mist produced were confirmed by tests. The test is a first test for confirming the correlation between the driving frequency of the ultrasonic transducer 6 and the amount of negative ions generated, and a second test for confirming the correlation between the driving frequency of the ultrasonic transducer 6 and the amount of mist generated. And a third test for confirming the water depth at which the amount of negative ions produced becomes maximum when the ultrasonic transducer 6 is driven at a certain driving frequency.

The ultrasonic vibrators 6 used in the test were prepared by using seven kinds of vibrating elements 6a each having a diameter of 20 mm and different resonance frequencies. The thickness dimension of the vibrating element 6a becomes thicker as the resonance frequency becomes lower, and becomes thinner as the resonance frequency becomes higher. For example, the resonance frequency is 1.6MH.
The thickness dimension of the z vibration element 6a is 1.2 mm, and the thickness dimension of the vibration element 6a having a resonance frequency of 2.5 MHz is 0.8 mm.

In the first test, seven kinds of ultrasonic transducers 6 exchangeably mounted in the water tank 3 were driven at different driving frequencies, and the number of negative ions was measured at a position 30 cm away from the mist outlet 4. By the way, the amount of mist generated greatly differs depending on the driving frequency of the ultrasonic transducer 6, and the thicker the thickness of the vibrating element 6a and the lower the driving frequency,
Drive power (input power) increases. Further, the amount of mist generated increases, and the amount of negative ions generated also increases. Specifically, as shown in FIG. 3, there is a peak of the amount of mist generation in the vicinity of 1.6 MHz.

Therefore, in the first test, the amount of negative ions produced was measured when the same amount of mist was produced per unit time. That is, the measurement result was adjusted by fixing the energy equivalent (at 3 cc / 10 minutes). The test results are shown in Table 1, and the diagram is shown in FIG.

[0036]

[Table 1]

As can be understood from FIG. 2, the peak of the amount of negative ions produced is around 4 MHz, and is 2 to 4.7 M.
It can be seen that negative ions can be effectively generated (20,000 or more) in the driving frequency band near Hz.
However, when the driving frequency is less than 2 MHz or more than 5 MHz, the production amount of negative ions is 200 in both cases.
It falls below 00.

In the second test, the seven types of ultrasonic transducers 6 exchangeably mounted in the water tank 3 were driven at different driving frequencies, and the amount (volume) of mist emitted from the mist outlet 4 per hour was measured. It was measured. The test results are shown in Table 2,
The chart is shown in FIG.

[0039]

[Table 2]

As shown in FIG. 3, the peak of the amount of mist generation is in a narrow range where the driving frequency of the ultrasonic transducer 6 is around 1.6 MHz, and the amount of mist generation sharply decreases on both sides of the driving frequency. That is, it can be seen that the drive frequency range in which a larger amount of negative ions can be generated while suppressing the amount of mist generated is in the band of 2 MHz or higher. Incidentally, as the driving frequency of the ultrasonic transducer 6 becomes higher, the particle size of mist becomes smaller, but the driving frequency becomes 5 MHz.
When the above is reached, almost no mist is generated, and thus the absolute amount of negative ions is drastically reduced.

Therefore, in the present invention, the first test and the second test
From the result of the test, the driving frequency of the ultrasonic vibrator 6 capable of generating a larger amount of negative ions while setting the amount of mist generation suppressed is set to 2 to 4.7 MHz, and more preferably
It was set to 2.5-4.5MHz so that negative ions could be effectively generated.

In the third test, seven kinds of ultrasonic transducers 6 were exchanged and mounted in the water tank 3, and the water depth V from the water surface to the vibrating surface of the ultrasonic transducer 6 was continuously changed at each driving frequency, The water level with the largest amount of negative ion generation per driving power was investigated. In other words, I searched for a water level that requires less running cost. The test results are shown in Table 3, and the chart is shown in FIG.

[0043]

[Table 3]

As shown in FIG. 4, the driving frequency band of the ultrasonic transducer 6 specified in the first test and the second test is 2 to 4.7 MHz.
It is understood that the water depth V of z should be 36 to 22 mm.
It should be noted that the shallower the water depth V is, the smaller the driving load of the ultrasonic vibrator 6 is. However, if the ultrasonic vibrator 6a is driven in a state where the surface of the vibrator 6a is exposed to the air, the vibrator 6a is destroyed, so that the water depth V of at least 5 mm Should be obtained. In addition,
The same test was performed using the ultrasonic transducer 6 in which the diameter of the vibrating element 6a was 25 mm, but similar results were obtained.

As described above, the ultrasonic transducer 6 is set to 2 to 4.7.
An ion generator driven at a drive frequency of MHz can generate a larger amount of negative ions while suppressing the amount of mist generated, and therefore indoor humidity becomes abnormally high even in the summer when the humidity is high. While avoiding, you can send a large amount of negative ions and make the indoor air environment comfortable. A water tank 2, a water tank 3, a passage 11 connected to the water tank 3,
It is desirable that the guide cylinder 15 and the mist adhering wall between the water tank 3 and the mist outlet 4 are made of an antibacterial material.

FIG. 5 shows another embodiment of the ion generator according to the present invention. There, the ultrasonic transducer 6 is driven in a no-load state due to misunderstanding by the user or inadvertent mistake,
The vibrating element 6a can be surely prevented from self-destructing. Specifically, a case 20 that opens upward is provided, this is fixed to the bottom wall of the water tank 3, and the upper surface of the opening of the case 20 is sealed with a lid 21.

The lid 21 is formed of a thin synthetic resin such as polycarbonate or polyethylene terephthalate or a thin metal plate such as stainless steel, and the converging portion 2 is formed in the center thereof.
2 was formed in the shape of a partial sphere that is recessed downward. The ultrasonic transducer 6 is attached to the bottom wall of the case 20, and a diffusion prevention cylinder 23 that prevents diffusion of vibration waves is fixed in the space inside the case 20 between the ultrasonic transducer 6 and the lid 21. Water was enclosed in 20. The liquid sealed in the case 20 may be a liquid other than water, for example, alcohol can be sealed. Also,
An air phase may exist in a part of the case 20 after the liquid is sealed.

In this embodiment, the upper surface of the vibrating element 6a is covered with the corrosion resistant layer 24 made of a stainless sheet or a plastic film so that the electrode and the vibrating element 6a can be protected. Further, in this embodiment, the water level sensor 25 is arranged inside the water tank 3, and the water level sensor 25
The water depth V can be maintained at a constant amount by opening and closing the solenoid valve 26 provided in the middle of the water supply passage 11a based on the output signal from the.

FIG. 6 shows another embodiment of the ion generator according to the present invention. There, the ultrasonic transducer 28 for generating mist and the ultrasonic transducer 6 for generating negative ions are arranged adjacent to each other on the bottom wall of the water tank 3. The ultrasonic transducer 28 for generating mist is composed of a disk-shaped vibrating element 28a and a rubber packing 28b attached to the outer peripheral edge of the vibrating element 28a, and is fixed by a holder 19. The ultrasonic oscillator 28 for generating mist is arranged at a position deeper (45 mm) than the ultrasonic oscillator 6 for generating negative ions, and its drive frequency is set to 1.6 to 1.7 MHz.

As described above, according to the ion generator provided with the ultrasonic vibrator 28 for generating mist and the ultrasonic vibrator 6 for generating negative ions, in the winter when it is easy to dry each ultrasonic wave Negative ions can be generated while generating a large amount of mist by simultaneously driving the vibrators 6 and 28 or driving only the ultrasonic vibrator 28 for generating mist. In the summer when the humidity is high, only the ultrasonic oscillator 6 for generating negative ions can be driven to generate negative ions while suppressing the generation of mist. When both ultrasonic transducers 6 and 28 are driven simultaneously, the inside of the water tank 3 should be divided into individual ultrasonic transducers 6 and 28 in order to prevent buffering of the oscillated ultrasonic waves. You can

Since the present invention is characterized in that the drive frequency of the ultrasonic transducer 6 is limited to a specific frequency band, the difference in the structure of the ion generator and the difference in the method of mixing mist and pressurized air. The technical idea of the present invention can be widely applied regardless of the above.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of an ion generator.

FIG. 2 is a chart showing the test results of the first test.

FIG. 3 is a chart showing test results of a second test.

FIG. 4 is a chart showing test results of a third test.

FIG. 5 is a sectional view showing another embodiment of the ion generator.

FIG. 6 is a sectional view showing still another embodiment of the ion generator.

[Explanation of symbols]

3 aquarium 4 mist exit 5 Blower fan 6 Ultrasonic transducer for negative ion generation 28 Ultrasonic transducer for mist generation

Claims (8)

[Claims] 1. A method for producing negative ions, in which an ultrasonic transducer 6 disposed in water is driven to generate mist in the air facing the water surface and at the same time negative ions are generated. Is generated at a drive frequency of 2 to 4.7 MHz. 2. The method for producing negative ions according to claim 1, wherein the water depth V from the water surface to the vibration surface of the ultrasonic transducer 6 is set to 5 to 36 mm to generate mist and negative ions. 3. An ultrasonic transducer 28 for generating mist in water.
And an ultrasonic transducer 6 for generating negative ions are arranged, and either or both of the ultrasonic transducers 6 and 28 can be driven to select a large or small amount of mist generation. 2. The method for producing negative ions according to 2. 4. A water tank 3 for storing water for mist generation,
The mist outlet 4 arranged to face the opening surface of the water tank 3, a blower fan 5 for sending pressurized air to the mist outlet 4 through the internal space of the water tank 3, and an ultrasonic wave mounted on the water tank 3. It has a vibrator 6 and sets the drive frequency of the ultrasonic vibrator 6 to 2 to 4.7 MHz to generate mist in the air in the water tank 3 and at the same time,
A negative ion generator that generates negative ions. 5. The anion generator according to claim 4, wherein the water depth V from the water surface in the water tank 3 to the vibration surface of the ultrasonic transducer 6 is set to 5 to 36 mm. 6. An ultrasonic transducer 2 for generating mist in a water tank 3.
8 and the ultrasonic vibrator 6 for generating negative ions are arranged respectively, and the ultrasonic vibrator 28 for generating mist is arranged at a position deeper than the ultrasonic vibrator 6 for generating negative ions. 6. The negative ion generator according to claim 4, wherein the driving frequency is set to 1.6 to 1.7 MHz. 7. A case 20 fixed to the water tank 3 and a lid 21 for sealing the upper surface of the opening of the case 20. An ultrasonic transducer 6 is attached to the bottom wall side of the case 20, The negative ion generation device according to claim 4, wherein a liquid that blocks no-load driving of the ultrasonic vibrator 6 is enclosed in a space inside the case between the ultrasonic vibrator 6 and the lid 21. 8. The anion generator according to claim 4, wherein the water supply tank 2, the water tank 3, the passage 11 connected to the water tank 3, and the mist adhering wall between the water tank 3 and the mist outlet 4 are subjected to antibacterial treatment.