JP6731586B2 - Nano bubble generator - Google Patents

Description

The present invention relates to a nanobubble generating device, and more particularly to a device for generating highly stable nanobubbles.

A liquid (mainly water) containing fine particles of gas is called micro-bubble water or nano-bubble water, and its use in a wide range of fields has been tried, and its bactericidal effect, deodorant effect, growth stimulating effect on plants, etc. have been reported. ing.

As a method for generating nano bubble water or micro bubble water, there are a pressure dissolution type and a method using an aspirator.

The pressure dissolution type utilizes the fact that a target gas is pressurized and melted in an airtight liquid container, and fine bubbles are formed in the liquid when the pressure is released.

In addition, the method using an aspirator is that water is pressure-fed to the aspirator, and fine bubbles are generated in the liquid when the gas taken in by the negative pressure generated on the output side of the aspirator and the liquid fed under pressure are mixed. Is used.

Furthermore, as disclosed in Japanese Patent No. 3682286, Japanese Patent No. 3822839, etc., the liquid is swirled in a spiral shape to take in gas at the swirling center, and the taken-in gas when the liquid is released from the swirling state. There is also an attempt to utilize the fact that is diffused in the liquid as fine particles.

In either method, micro-order bubbles are obtained in the liquid, and when ultrasonic waves are applied to the micro-order bubbles, the micro-order bubbles become nano-sized bubbles of smaller size. Alternatively, it is considered that there are air bubbles that are already in the nano-order before ultrasonic waves are applied.

Japanese Patent No. 3682286 Japanese Patent No. 3822839

With any of the above methods, it is possible to generate nano-order bubbles (nano-bubbles) and micro-order bubbles (micro-bubbles) in the liquid, but the quality, especially the life, is several seconds to several times for micro-order bubbles. Bubbles of nano-order disappearing in 10 seconds, so-called nano bubbles are limited to 1 month (see Comparative Example of the present application).

As mentioned above, the liquid (water) containing nano-order bubbles is being considered for use in various fields such as medical, industrial, and agricultural purposes, but as mentioned above, it has a life of only about one month. Then, the producer is required to make the product and immediately to ship it, and the user is required to purchase it and immediately use it, so that the stockpile cannot be reserved in advance.

Therefore, when it is attempted to use nano-order bubbles for stimulating the growth of plants, it is necessary to have a nano-bubble generator as a facility near the farm. However, the nano (micro) bubble generator as a facility is expensive and not in a state where it can be easily purchased.

The present invention has been proposed in view of the above-mentioned conventional circumstances, and an object of the present invention is to provide a nanobubble generation device in which the generated nanoparticles have a long stability period, and the structure is simple and inexpensive. And

According to the present invention, when a liquid is pumped by a pump, an aspirator is interposed in a flow path of the liquid to generate a bubble mixed liquid. The bubble mixture from the aspirator from the nozzle, at a position above the liquid ejection port than draft position, but will be ejected to the outside, the nozzle at this time, tip, from draft on the sidewalls of the container Opened in parallel at the upper position, the bubble-mixed liquid from the aspirator is jetted from the tip so as to form a liquid film spreading along the shape of the wall surface. As a result, the particle size adjusting plate is formed. That is, cavitation is formed between the liquid film and the wall surface of the container, and the cavitation adjusts the particle size of bubbles contained in the liquid.
The bubbles of which the particle size is adjusted are housed in a reservoir of water together with a liquid film covering the bubbles, and are made into nano by ultrasonic waves from an ultrasonic transmitter placed here.

With the above configuration, first, micro-sized bubbles or nano-ordered bubbles are formed in the aspirator, and when the pressure in the hose from the aspirator to the nozzle is high, a part of the gas is dissolved in the liquid under pressure. Become.

When the bubble-mixed liquid is discharged from the nozzle toward the particle size adjusting plate, the liquid is a thin film-like surface along the particle size adjusting plate because the adjusting plate is parallel to the jetting direction of the nozzle. (Liquid film) is formed. At this time, an extremely thin cavitation with a negative pressure corresponding to the speed of the liquid, which is covered with the liquid film, is formed at the boundary between the particle size adjusting plate and the liquid film, and the gas contained in the liquid is attracted to the cavitation. .. Further, when the gas is dissolved under pressure in the liquid, the dissolved gas is returned to the gas by cavitation. The gas formed at this time becomes fine particles having a particle size (micro-order) according to the thickness of cavitation, and the liquid is stored in the container in a state of being clouded by the fine particles. By applying ultrasonic waves to the fine particles with an ultrasonic oscillator, nanobubbles having a long life can be generated.

The figure which shows the outline|summary of this invention. The top view of the container part of FIG. Comparative example. Comparative example and the present invention. The figure which shows the principle of this invention. The graph which shows the example of a measurement result. The figure which shows other embodiment of this invention. The figure which shows the example of cavitation.

1 shows an embodiment of the present invention, and FIG. 2 is a plan view of a container portion. Hereinafter, a case where water is used as a liquid and air is used as a gas will be described as an example.

Water from the container 10 is pumped to the aspirator 12 via the hose 15 and the pump 11. In the aspirator 12, the air is taken into the water by utilizing the negative pressure when the water to be pumped is ejected. The air taken in will form bubbles in the water. Therefore, by adjusting conditions such as the inflow pressure of water into the aspirator 12 and the amount of air taken in, micro- or nano-order bubbles are formed in the water at this stage. Will be done. It goes without saying that air bubbles with a diameter larger than the micro and nano orders are mixed.

In this way, the water containing bubbles is further pumped and ejected from the nozzle 13 at the tip of the hose 14. Here, when the nozzle diameter is small, the water is pressurized in the hose 14 and a part of the air bubbled as described above is dissolved in the water.

The tip of the nozzle 13 is against the wall surface w of the container 10 (the wall surface w has the function of adjusting the particle size as described below, so the particle size adjusting plate may be used as a superordinate concept). Water is sprayed from the nozzle 13 along the wall surface w of the container 10 to form a water film m that spreads along the shape of the wall surface w. It will be submerged in the water stored in the container 21. At this time, a very thin planar negative pressure layer (cavitation c) is formed between the water film m ejected from the nozzle 13 and the container 10.

As described below, the water containing micro-order bubbles is cavitationally c sinked into the accumulated water in the container 10 and ultrasonic waves are applied thereto, where the micro-order bubbles become nano-order bubbles. Of course, some bubbles are already in the nano-order when emitted from the nozzle 13.

In FIG. 1, water is sucked up by the pump 11 from the container 10 (water source) and returns to the container 10 again. In this case, the water in the container 10 is circulated several times, but it is not always necessary to circulate the water if the functions of the pump 11 and the aspirator 12 are sufficient.

FIG. 5 is a diagram for explaining the principle of the present invention.

As shown in FIG. 5, water in which micro- or nano-order bubbles have been formed in the aspirator 12 is ejected from the nozzle 13 and becomes a water film m which flows down planarly along the container wall surface w. At this time, an extremely thin negative pressure cavitation c covered with the water film is formed between the water film m and the container wall surface w. According to Bernoulli's theorem, the magnitude of the negative pressure becomes lower as the ejection speed from the nozzle 13 becomes higher. Micro- or nano-order bubbles formed by the aspirator 12 and present in the water film m are drawn into the cavitation c.

Further, the air taken in by the aspirator 12 may be dissolved in water by the pressure in the hose 14, but at this time, the dissolved air returns to gas by the negative pressure of the cavitation c, and The gas is restrained by cavitation c. Therefore, it is estimated that the bubbles b1 having a particle size regulated by the thickness of the cavitation c are formed between the water film m and the container wall surface w.

In this state, the bubble b1 is submerged in the water stored in the container 10 along the wall surface w of the container while being covered with the water film m on the upper side thereof. After this, it will float again on the surface of the water, and when the ejection from the nozzle 12 is started, the surface of the water becomes cloudy with the bubbles. The particle size of the cloudy bubbles is considered to be in the micro order, which can be inferred from the state of particles that are visually cloudy and cloudy.

At this time, the air bubbles b2 having a large buoyancy and a particle size of micro-order or more are also emitted from the nozzle 13, but since such air bubbles have a large buoyancy, they are emitted into the air without being restricted by the cavitation c. it is conceivable that. That is, the micro- or nano-order bubbles b1 and the bubbles b2 scattered in the air are separated by the container wall surface (particle size adjusting plate), and only the bubbles having a diameter equal to or smaller than a predetermined value regulated by the thickness of the cavitation c are contained in the stored water. Will exist.

The micro-order air bubbles that make the surface of the water cloudy in this way gradually disappear when the jet of water from the nozzle 13 is stopped, but unlike the air bubbles of the milli-order which have a large buoyancy, they remain in water. The time is relatively long, lasting from 30 seconds to nearly 1 minute. Since the invention of the present application is to generate nanobubbles (here, the water surface is cloudy), ultrasonic waves are applied by an ultrasonic transmitter placed in the reservoir. As a result, the micro-order bubbles are instantly destroyed and become nano-order bubbles that cannot be visually observed.

In addition, in FIG. 5, the state in which the cavitation c and the water film m are separated is shown, but this is only a schematic diagram for helping understanding, and in reality, there is no such a clear boundary, It is a pressure space in which the negative pressure gradually increases from the surface side of the membrane m (upper side in FIG. 5) toward the container wall surface w.

Table 1 shows the number and lifetime of nano-order bubbles produced in various modes. Here, an element for generating a fog of 1.7 MHz was used as the ultrasonic transmitter, and the measuring device was a nanosite manufactured by Japan Tandem Co., Ltd. The particle size distribution typically gives a distribution curve having a peak in the vicinity of 100 nm between 50 nm and 200 nm as shown in FIG. 6, for example. This distribution curve is slightly different depending on the jetting speed from the nozzle or the jetting mode as in the following samples (a) to (d).

In Table 1, sample (a) corresponds to FIG. 3(a), and is an example in which the nozzle opening is directly discharged into water accumulated in the container to form nano-order bubbles. In this example, micro-order bubbles are also formed but disappear at the time of measurement, and bubbles above the micro-order disappear due to buoyancy immediately after being ejected.

The sample (b) corresponds to FIG. 3(b), and is an example in which ultrasonic waves are further applied by the ultrasonic wave generator 30 to the embodiment of FIG. 3(a). In this example, because ultrasonic waves are applied, bubbles of micro-order do not disappear and become bubbles of nano-order by ultrasonic waves.Furthermore, bubbles of micro-order and above do not break even by ultrasonic waves and scatter into the air immediately by buoyancy. To do.

Sample (c) corresponds to Fig. 4(a), and is an example in which water is jetted along the wall surface of the container to form micro (nano)-order bubbles. Sample (d) corresponds to FIG. 4(b) and is an example (Example of the present application) in which ultrasonic waves are further applied to the example of FIG. 4(a). 3(c) is a plan view of FIG. 3(a)(b), and FIG. 4(c) is a plan view of FIG. 4(a)(b). ), the ultrasonic transmitter of FIG. 4(b) is omitted.

In this embodiment, the water in the container 10 passes through the nozzle 13 about 10 times, the ejection speed from the nozzle 13 is about 8 to 9 m/s, and the blowing pressure to the aspirator 12 is about 7 Mp.

In Table 1, sample (b) has more fine particles than sample (a) and sample (d) has more ultrasonic waves than sample (c). On the other hand, the sample (c) has a longer life than the sample (a) and the sample (d) has a longer life than the sample (b) and is stable. That is, it is considered that the bubble-mixed water ejected from the nozzle 13 is caused to flow along the wall surface w of the container. In particular, since the sample (d) is subjected to ultrasonic waves along the wall surface w of the container, it has a large number of nano-sized bubbles and has a life of 3 months or more, proving its high practicality.

The measurement of the nanosite utilizes the reflection of laser light, and there is an index called Relative Intensity which represents the ratio of the light intensity from each particle at this time. Even if the particle size is the same, there are particles with strong light and particles with weak light. Therefore, looking at the distribution of Relative Intensity for each of the above samples, the longer the life of the sample, the narrower the range of Relative Intensity is distributed, that is, the difference in the reflection intensity of light from each particle is small, but the life is short. The sample shows a spread in the distribution of Relative Intensity.

According to Bernoulli's theorem, the cavitation c has a larger negative pressure as the ejection velocity increases. Although it is merely visual observation, when the ejection speed is about 8 to 9 m/s or more, a cloudy state is formed in the accumulated water at the moment of ejection from the nozzle 13, and the nozzle diameter is increased to increase the ejection speed to 5 m/s. If it is set to about s, a cloudy state can be observed in the accumulated water after a while from the jet from the nozzle 13. When the nozzle diameter is further increased and the jetting speed is set to about 2 to 3 m/s, the accumulated water does not reach "white turbidity", and bubbles can be confirmed to the extent that vague clouds are drifting. Even in this state, if the water filled in the container 10 is continuously rotated several times by the pump 11 (even if it takes time), the number of bubbles in the nano-order increases, and the duration (life) is 8 to 9 m/s. It is comparable to the nano-sized bubbles formed before and after.

Samples (e) and (f) in Table 2 are those in which water containing fine bubbles was generated under the same conditions as sample (d), and the number of particles was measured with time. Sample (e) was stored refrigerated at 15°C, and sample (f) was stored at room temperature. In sample (f), the number of samples rapidly declined at the time of measurement at the 4th month. It is considered that one of the reasons is that the high temperature continued for the summer when two months passed. In any case, when the device of the present invention is used, a stable number can be maintained for 3 months or more.

Here, it should be noted that the sample (a), that is, even if the output of the aspirator 12 is ejected from the nozzle 13 as it is, nano-sized bubbles (temporarily also micro-ordered bubbles) are formed. .. Furthermore, when ultrasonic waves are applied to it (the sample (b) above), the micro-sized bubbles are also nanosized, so that a larger number of nano-sized bubbles are formed than in the case of the sample (d) in Table 1. That is the point.

From this fact, when the output of the aspirator 12 is ejected from the nozzle 13 as it is, when the nano- or micro-order bubbles are not formed, the cavitation c does not absorb the fine bubbles, so that the nano-order bubbles of the present invention (Table One sample (d)) is not formed. Since the pressure-dissolved water forms bubbles having a diameter corresponding to the thickness of the cavitation at the time of ejection from the nozzle 13, it is necessary to be pressure-dissolved between the aspirator 12 and the nozzle 13.

Therefore, the essence of the present invention is that the formed micro/nano-order bubbles or the pressurized dissolved water are guided to the cavitation c to form bubbles having a particle size equal to or smaller than the size regulated by the cavitation c. The bubbles guided to the cavitation c are divided even if the diameter is larger than the thickness of the cavitation c at the beginning, and are regulated by the thickness of the cavitation c according to the flow, so that the number increases as the accumulated water becomes cloudy. Thought to be a thing.

The opening position of the nozzle 13 is a position above the draft as shown in FIGS. However, as long as the ejection velocity as described above is secured, it may be opened in water, but in order to form a water film with a ejection velocity of 5 m/s or more in water, a considerable pump is required. The ability is required and the cost is high. Further, in order to exert the effect of the negative pressure of the cavitation c on the water film, it is considered that the thickness of the water film should be thin, but the presence of the surrounding water does not allow this.

The ejection direction of the nozzle 13 is not particularly limited, but it is a direction in which the water film m is easily formed, and when the container wall surface w is used as a particle size adjusting plate, it is generally a horizontal direction.

Further, the container wall surface w has a function of a particle size adjusting plate for adjusting the particle size of micro-order bubbles to a size not more than the size regulated by the cavitation c, but its shape is not particularly limited. When the container wall surface w is used as the particle size adjusting plate as shown in FIGS. 1 and 3, the shape of the container is limited. That is, in FIG. 1, it is a curved surface using a part of a cylinder, and in FIG. 3, it is a flat surface. Of course, it is recognized that a plate other than the container 10 may be used. When using a curved surface, it is necessary that the curved surface is curved in the direction of receiving the water flow from the nozzle 13. For example, even if the nozzle is arranged tangentially outside the cylinder, the liquid (water) ejected from the nozzle is not caught by the curved surface.

FIG. 6(a) shows an example of a particle size adjusting plate utilizing a plane different from the wall surface of the container, FIG. 6(b) is a side view thereof, and FIG. 6(c) is its a-a sectional view.

The two flat plates 51a and 51b are fixed with a predetermined gap (for example, 1 mm or less) fixed to form a fan-shaped water channel 52. The bubble-mixed liquid ejected from the nozzle 13 forms cavitation c between the flat plates 51a and 51b on both sides to form micro-order bubbles. In this case, since the bubble mixed liquid is ejected while being in contact with the particle size adjusting plates (flat plates 51a, 51b) on both sides, compared to the case where only one side (container surface side) is in contact with water as in the above example. Although the deceleration effect works and a large effect cannot be expected, it has the advantage that it can be used as a throw-in type because it does not receive the pressure of the accumulated water even if it is submerged.

Next, there are various forms of the cavitation c. For example, as shown in FIG. 8, when a part of the hose 12 is thickened and high-speed water is flowed from the smaller diameter to the thicker, the hose 12 is changed from the thinner part to the thicker part. The step portion 40 at the time of transition becomes negative pressure (that is, cavitation). Even in this state, micro- and nano-order bubbles can be formed, but the effect is far inferior to the case of using planar cavitation as in the present application.

Further, even by simply flowing water at a high speed in a hose having a uniform diameter, cavitation can be made in a portion along the peripheral wall portion, and bubbles partially collect in the cavitation. However, as a whole, the central part of the hose has a larger flow velocity than the part near the peripheral wall, and according to Bernoulli's theorem, the pressure in the radial direction of the hose becomes smaller toward the central part, so that all the bubbles cause cavitation in the peripheral wall. I don't concentrate. Therefore, in this case, the effect of reducing the particle size in the cavitation of the peripheral wall of the hose 14 is small.

If a thin water flow can be formed only along the peripheral wall of the hose 14 (the center part is hollow), the same effect as in FIGS. 4(a) and 4(b) can be obtained. It is possible.

FIGS. 3(a) and 3(b) actually realize the above state as a device. As described above, in the example shown in FIG. 3(a), the accumulated water does not become cloudy as in the example shown in FIGS. 4(a) and 4(b). The sample (a) of Table 1 corresponding to FIG. 3(a) has a small number and a short life. In addition, in the sample (b) of Table 1 corresponding to FIG. 3B, ultrasonic waves are applied to all bubbles of nano-order, micro-order, and milli-order, so the number of bubbles of nano-order at the time of creation is Although it is larger than the sample (d) of the present invention, it is impossible to measure after 2 months since it is severely attenuated with time. It is considered that the particle size is not adjusted by the planar cavitation as in the present invention.

On the other hand, in the present invention, the water discharged from the nozzle tip at a flow velocity of 8 to 9 m/s has already spread to around 100 mm at 30 mm ahead, and the present invention is far larger in terms of the contact area with the wall surface, and , In this part, a thin and stable cavitation c is formed between the container and the peripheral wall of the container, so the particle size of the bubbles created by the nozzle is further reduced by the cavitation c, and stable bubbles with uniform particle size are obtained. The accumulated water becomes cloudy like a fog before ultrasonic waves are applied.

As shown in FIG. 4(b) (Table 1: Sample (d), Sample (e)) using ultrasonic waves of 38 kHz, water was made to contain fine air bubbles of nano order. The number of particles was slightly less than 500 million/ml, which was a little smaller than that of the case of creating at 1.7 MHz, but the particle size distribution has a peak in the vicinity of 200 nm. The life was shorter than the case of forming at 1.7 MHz (3 months or more) and was about 2 months. Therefore, regarding the formation of fine bubbles using the present invention, although the frequency of ultrasonic waves is not limited, the life can be said to be shorter as the wavelength is longer.

As described above, the nanobubble water of the present application (water containing bubbles of nanoorder) has a longer life than nanobubble water produced by other methods, and the following effects are recognized. When the nanobubble water of the present invention was sprayed on one corner of the vineyard of Shirayuri Brewery Co., Ltd. (Katsunuma City, Yamanashi Prefecture), no disease or mold damage occurred on that corner. It is presumed that it has a sterilizing effect on the bacteria that parasitize the fruit trees and an antifungal effect against mold. In addition, when the life of cut roses was tested at the Osaka Tsurumi Flower Center, the nanobubble water of the present invention lasted longer than the case of using a commercially available life prolonging agent. It is considered to exert a sterilizing effect on bacteria which naturally exist in water and shorten the life of flowers. Furthermore, by using the nanobubble water of the present invention for cleaning the wastewater pipe of the condominium, the slime adhering to the pipe could be completely removed. In addition, there is a lot of complaints from residents due to a bad odor caused by cleaning the pipes using ordinary water, but the nano bubble water of the present invention did not cause any bad odor. It is considered that it has a large penetrating effect on slime and a large deodorizing effect.

The case where air is used as the gas and water is used as the liquid has been described above, but the present invention is not limited to this.

As described above, according to the present invention, the bubble mixed liquid formed by the aspirator or the bubble mixed liquid formed after being pressure-dissolved in the liquid is reprocessed to nanosize bubbles having a uniform diameter. Therefore, it has a long life, and its utility value in the medical, agricultural and industrial fields is extremely high.

10, container 11, pump 12, aspirator 13, nozzle 14, 15 hose c, cavitation m, water film w, container wall surface

Claims (1)

A pump for pumping the liquid stored in the container ,
An aspirator that mixes a gas with respect to the liquid pumped from the pump to generate a bubble mixed liquid,
The tip is opened in parallel with respect to the wall surface of the container at a position above the draft so that the bubble mixed liquid from the aspirator forms a liquid film spreading from the tip along the shape of the wall surface. A nozzle that jets to
Cavitation formed between the liquid film and the container wall surface, for adjusting the particle size of the bubbles contained in the liquid, a particle size adjusting plate utilizing the shape of the container wall surface ,
An ultrasonic transmitter that applies ultrasonic waves to the liquid from the particle size adjusting plate,
An apparatus for producing nanobubbles, comprising:

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