JP2022159989A - Device for generating ozone-containing ultrafine bubble liquid, and method for generating ozone-containing ultrafine bubble liquid - Google Patents

Abstract

To provide a device for generating an ozone-containing UFB liquid and a method for generating an ozone-containing UFB liquid with which it is possible to generate an ozone-containing UFB liquid that can be stored for a long time at a high concentration.SOLUTION: A liquid containing oxygen as a dissolved gas is film-boiled to generate a UFB liquid, and the generated UFB liquid is irradiated with UV light.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to an ozone-containing ultra-fine bubble liquid generating apparatus and an ozone-containing ultra-fine bubble liquid generating method.

In Patent Literature 1, oxygen nanobubble water having a diameter of 10 nm or more and 500 nm or less is generated by generating a swirl flow in water mixed with oxygen and causing the swirl flows to collide with each other. Then, it is described that by irradiating the generated oxygen nanobubble water with ultraviolet rays, ozone water containing ozone nanobubbles is generated.

In a liquid containing ultra-fine bubbles (hereinafter also referred to as “UFB”) (nanobubbles) with a diameter of less than 1.0 μm, it is desired that the UFB remain in the liquid without floating. The floating speed of bubbles can be calculated from the Stokes formula, and the speed is proportional to the square of the particle size. Therefore, the particle size of UFB has a large effect as a rate factor, and the particle size of UFB greatly affects the reliability of a liquid containing UFB. In order to obtain a highly reliable UFB liquid, it is desirable to use a UFB with a uniform grain size of about 100 nm in order to suppress the floating speed.

Japanese Unexamined Patent Application Publication No. 2011-200778

However, the bubbles obtained by the method of Patent Literature 1 contain bubbles larger than the desired particle size, and the bubbles larger than the desired particle size float and disappear over time. As a result, there is a problem that it is not possible to obtain a UFB solution with a high concentration that can be stored for a long period of time.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an ozone-containing UFB liquid generating apparatus and an ozone-containing UFB liquid generating method capable of generating an ozone-containing UFB liquid that can be stored for a long time at a high concentration.

Therefore, the apparatus for generating an ozone-containing ultra-fine bubble liquid of the present invention includes an ultra-fine bubble generating means for generating ultra-fine bubbles by causing film boiling in a liquid in which a gas containing oxygen is dissolved by means of a heating part. and irradiating means for irradiating the liquid in which the ultra-fine bubbles are generated with ultraviolet rays.

Further, the method for generating an ozone-containing ultra-fine bubble liquid of the present invention includes an ultra-fine bubble generation step of generating ultra-fine bubbles by causing film boiling in a liquid in which a gas containing oxygen is dissolved by a heat generating part. and an irradiation step of irradiating the liquid in which the ultra-fine bubbles are generated with ultraviolet rays.

According to the present invention, it is possible to provide an ozone-containing UFB liquid generation apparatus and an ozone-containing UFB liquid generation method capable of generating an ozone-containing UFB liquid that can be stored for a long time at a high concentration.

It is a figure which shows an example of the production|generation apparatus of UFB liquid. 4 is a schematic configuration diagram of a pretreatment unit; FIG. FIG. 3 is a diagram for explaining a schematic configuration diagram of a dissolving unit and a dissolving state of a liquid; 1 is a schematic configuration diagram of a T-UFB generation unit; FIG. FIG. 3 is a diagram showing the detailed structure of a heating element; FIG. 4 is a diagram showing how film boiling occurs when a predetermined voltage pulse is applied to a heating element; FIG. 4 is a diagram showing how UFB is generated with the generation and expansion of film boiling bubbles. FIG. 4 is a diagram showing how UFB is generated as a film boiling bubble shrinks. FIG. 4 illustrates how reheating a liquid produces UFB. FIG. 10 is a diagram showing how UFB is generated by impact when film boiling bubbles disappear. 4 is a diagram showing a configuration example of a post-processing unit; FIG. 1 is a schematic diagram showing an apparatus for generating ozone-containing UFB liquid; FIG. 1 is a schematic diagram showing an apparatus for generating ozone-containing UFB liquid; FIG. 1 is a schematic diagram showing an apparatus for generating ozone-containing UFB liquid; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In addition, the following embodiments do not limit the present invention. In this specification, the ozone-containing ultra-fine bubble liquid (ozone-containing UFB liquid) means that the liquid containing ultra-fine bubbles contains ozone. That is, ozone may exist as UFB in the liquid, or may exist in a dissolved state in the liquid. The oxygen-containing ultra-fine bubble liquid (oxygen-containing UFB liquid) also means that oxygen is contained in the liquid containing ultra-fine bubbles, similarly to the ozone-containing UFB liquid.

(First embodiment)
A first embodiment of the present invention will be described below with reference to the drawings.

<<Configuration of UFB liquid generation device>>
An outline of a UFB liquid generating apparatus utilizing the film boiling phenomenon will be described below.

FIG. 1 is a diagram showing an example of a UFB liquid generation apparatus applicable to this embodiment. The ultra-fine bubble liquid generation device 1 of this embodiment includes a pretreatment unit 100 , a dissolution unit 200 , a T-UFB generation unit (ultra-fine bubble generation means) 300 , a post-treatment unit 400 and a collection unit 500 . The liquid W such as tap water supplied to the pretreatment unit 100 is subjected to treatment specific to each unit in the order described above, and is recovered by the recovery unit 500 as a T-UFB liquid. The function and configuration of each unit will be described below. Although the details will be described later, in this specification, UFB generated by utilizing film boiling accompanying rapid heat generation is referred to as T-UFB (Thermal-Ultra Fine Bubble).

FIG. 2 is a schematic configuration diagram of the pretreatment unit 100. As shown in FIG. The pretreatment unit 100 of the present embodiment deaerates the supplied liquid W. As shown in FIG. The pretreatment unit 100 mainly has a deaeration container 101, a shower head 102, a decompression pump 103, a liquid introduction path 104, a liquid circulation path 105, and a liquid extraction path . A liquid W such as tap water is supplied from the liquid introduction passage 104 to the degassing container 101 via the valve 109 . At this time, the shower head 102 provided in the deaeration container 101 atomizes the liquid W into the deaeration container 101 . The shower head 102 is for promoting vaporization of the liquid W, but a centrifugal separator or the like can be substituted as a mechanism for producing the effect of promoting vaporization.

After a certain amount of the liquid W is stored in the degassing container 101, when the decompression pump 103 is operated with all the valves closed, the already vaporized gas component is discharged and dissolved in the liquid W. Vaporization and evacuation of gaseous components present are also promoted. At this time, the internal pressure of the degassing container 101 may be reduced to about several hundred to several thousand Pa (1.0 Torr to 10.0 Torr) while checking the pressure gauge 108 . Gases deaerated by the deaeration unit 100 include, for example, nitrogen, oxygen, argon, carbon dioxide, and the like.

The degassing process described above can be repeatedly performed on the same liquid W by using the liquid circulation path 105 . Specifically, the shower head 102 is operated with the valve 109 of the liquid introduction path 104 and the valve 110 of the liquid outlet path 106 closed and the valve 107 of the liquid circulation path 105 opened. As a result, the liquid W stored in the degassing container 101 and subjected to the degassing process once is sprayed again into the degassing container 101 via the shower head 102 . Furthermore, by activating the decompression pump 103, the vaporization process by the shower head 102 and the degassing process by the decompression pump 103 are performed on the same liquid W at the same time. Then, the gas component contained in the liquid W can be reduced step by step each time the above-described repeated processing using the liquid circulation path 105 is performed. When the liquid W degassed to the desired purity is obtained, the valve 110 is opened to send the liquid W to the dissolving unit 200 through the liquid lead-out path 106 .

Although FIG. 2 shows the degassing unit 100 that vaporizes the dissolved matter by reducing the pressure of the gas portion, the method of degassing the dissolved liquid is not limited to this. For example, a heat boiling method in which the liquid W is boiled to vaporize the dissolved matter may be employed, or a membrane degassing method in which a hollow fiber is used to increase the interface between the liquid and the gas may be employed. SEPAREL series (manufactured by Dainippon Ink Co., Ltd.) is commercially available as a degassing module using hollow fibers. This uses poly-4-methylpentene-1 (PMP) as the raw material of the hollow fiber membrane, and is mainly used for the purpose of degassing air bubbles from the ink supplied to the piezo head. Furthermore, two or more of the vacuum degassing method, the heat boiling method, and the membrane degassing method may be used in combination.

By performing the above-described deaeration treatment as a pretreatment, the purity and solubility of the desired gas in the liquid W can be increased in the dissolution treatment described later. Furthermore, in the T-UFB generation unit, which will be described later, the concentration of desired UFB contained in the liquid W can be increased. That is, by providing the pretreatment unit 100 before the dissolution unit 200 and the T-UFB generation unit 300, it becomes possible to efficiently generate a highly concentrated UFB liquid.

3(a) and 3(b) are diagrams for explaining the schematic configuration of the dissolving unit 200 and the dissolving state of the liquid. The dissolution unit 200 is a unit that dissolves a desired gas in the liquid W supplied from the pretreatment unit 100 . The dissolving unit 200 of this embodiment mainly has a dissolving container 201 , a rotating shaft 203 to which a rotating plate 202 is attached, a liquid introduction path 204 , a gas introduction path 205 , a liquid outlet path 206 and a pressure pump 207 .

The liquid W supplied from the pretreatment unit 100 is supplied to the dissolution container 201 through the liquid introduction path 204 and stored therein. On the other hand, the gas G is supplied to the dissolving container 201 through the gas introduction path 205 .

When predetermined amounts of the liquid W and the gas G are stored in the dissolving container 201, the pressure pump 207 is operated to increase the internal pressure of the dissolving container 201 to approximately 0.5 MPa. A safety valve 208 is arranged between the pressure pump 207 and the dissolving container 201 . Further, by rotating the rotating plate 202 in the liquid via the rotating shaft 203, the gas G supplied to the dissolution container 201 is bubbled, the contact area with the liquid W is increased, and the dissolution into the liquid W is facilitated. Facilitate. Such operations are continued until the solubility of the gas G reaches approximately the maximum saturation solubility. At this time, means for lowering the temperature of the liquid may be arranged in order to dissolve as much gas as possible. Moreover, in the case of a hardly soluble gas, it is possible to increase the internal pressure of the dissolving container 201 to 0.5 MPa or higher. In that case, it is necessary to optimize the material of the container from a safety point of view.

After obtaining the liquid W in which the components of the gas G are dissolved at the desired concentration, the liquid W is discharged through the liquid lead-out path 206 and supplied to the T-UFB generation unit 300 . At this time, the back pressure valve 209 adjusts the flow pressure of the liquid W so that the pressure during supply does not become higher than necessary.

FIG. 3(b) is a diagram schematically showing how the mixed gas G is dissolved in the dissolution container 201. As shown in FIG. Bubbles 2 containing the component of gas G mixed in liquid W dissolve from the portion in contact with liquid W. As shown in FIG. Therefore, the bubble 2 gradually shrinks, and the gas-dissolved liquid 3 exists around the bubble 2 . Since buoyancy acts on the bubble 2 , the bubble 2 moves to a position off the center of the gas-dissolved liquid 3 or separates from the gas-dissolved liquid 3 to become a residual bubble 4 . That is, the liquid W supplied to the T-UFB generation unit 300 through the liquid lead-out path 206 includes the gas-dissolved liquid 3 surrounding the bubbles 2 and the gas-dissolved liquid 3 and the bubbles 2 separated from each other. There are mixed states.

In the figure, the gas-dissolved liquid 3 means "a region in the liquid W in which the dissolved concentration of the mixed gas G is relatively high". In the gas component actually dissolved in the liquid W, the concentration is highest around the bubble 2 or even in the state separated from the bubble 2, and the concentration of the gas component is continuous as the distance from that position increases. relatively low. That is, in FIG. 3B, the area of the gas-dissolved liquid 3 is surrounded by a dashed line for explanation, but such a clear boundary does not actually exist. Further, in the present embodiment, gas that is not completely dissolved is allowed to exist in the liquid in the form of bubbles.

FIG. 4 is a schematic diagram of the T-UFB generation unit 300. As shown in FIG. The T-UFB generation unit 300 mainly includes a chamber 301, a liquid introduction path 302, and a liquid outlet path 303. Flow from the liquid introduction path 302 through the chamber 301 toward the liquid outlet path 303 is generated by a flow pump (not shown). formed by Various types of pumps such as diaphragm pumps, gear pumps, and screw pumps can be used as fluid pumps. The liquid W introduced from the liquid introduction path 302 is mixed with the gas-dissolved liquid 3 of the gas G mixed by the dissolving unit 200 .

An element substrate 12 provided with heat generating elements 10 is arranged on the bottom surface of the chamber 301 . By applying a predetermined voltage pulse to the heating element 10 , a bubble 13 caused by film boiling (hereinafter also referred to as a film boiling bubble 13 ) is generated in a region in contact with the heating element 10 . As the film boiling bubbles 13 expand and contract, ultra-fine bubbles (UFB 11) containing the gas G are generated. As a result, the UFB liquid W containing many UFBs 11 is led out from the liquid lead-out path 303 .

5A and 5B are diagrams showing the detailed structure of the heating element 10. FIG. FIG. 5(a) shows the vicinity of the heating elements 10, and FIG. 5(b) shows a cross-sectional view of the element substrate 12 in a wider area including the heating elements 10. As shown in FIG.

As shown in FIG. 5A, in the element substrate 12 of this embodiment, a thermal oxide film 305 as a heat storage layer and an interlayer film 306 also serving as a heat storage layer are laminated on the surface of a silicon substrate 304. . A SiO ₂ film or a SiN film can be used as the interlayer film 306 . A resistance layer 307 is formed on the surface of the interlayer film 306 , and wiring 308 is partially formed on the surface of the resistance layer 307 . As the wiring 308, an Al alloy wiring such as Al, Al--Si, or Al--Cu can be used. A protective layer 309 made of an SiO ₂ film or a Si ₃ N ₄ film is formed on the surfaces of these wirings 308 , resistance layer 307 and interlayer film 306 .

On the surface of the protective layer 309, the portion corresponding to the heat acting portion 311 that eventually becomes the heating element 10 and its surroundings are covered with the protective layer 309 against chemical and physical impacts accompanying the heat generation of the resistance layer 307. An anti-cavitation film 310 is formed to protect the . A region on the surface of the resistance layer 307 where the wiring 308 is not formed is a heat acting portion 311 where the resistance layer 307 generates heat. A heat-generating portion of the resistance layer 307 where the wiring 308 is not formed functions as a heat-generating element (heater) 10 . Thus, the layers of the element substrate 12 are sequentially formed on the surface of the silicon substrate 304 by semiconductor manufacturing techniques, whereby the silicon substrate 304 is provided with the heat acting portion 311 .

Note that the configuration shown in the drawing is an example, and various other configurations are applicable. For example, a configuration in which the resistive layer 307 and the wiring 308 are stacked in reverse order, and a configuration in which an electrode is connected to the lower surface of the resistive layer 307 (so-called plug electrode configuration) are applicable. In other words, as will be described later, any configuration may be used as long as the liquid can be heated by the heat acting portion 311 to cause film boiling in the liquid.

FIG. 5B is an example of a cross-sectional view of a region including a circuit connected to the wiring 308 in the element substrate 12. As shown in FIG. An N-type well region 322 and a P-type well region 323 are partially provided on the surface layer of the silicon substrate 304, which is a P-type conductor. A P-MOS 320 is formed in the N-type well region 322 and an N-MOS 321 is formed in the P-type well region 323 by introducing and diffusing impurities such as ion implantation by a general MOS process.

The P-MOS 320 is composed of a source region 325 and a drain region 326 formed by partially introducing an N-type or P-type impurity into the surface layer of the N-type well region 322, a gate wiring 335, and the like. A gate wiring 335 is deposited on the surface of the portion of the N-type well region 322 excluding the source region 325 and the drain region 326 via a gate insulating film 328 with a thickness of several hundred angstroms.

The N-MOS 321 is composed of a source region 325 and a drain region 326 formed by partially introducing an N-type or P-type impurity into the surface layer of a P-type well region 323, a gate wiring 335, and the like. A gate wiring 335 is deposited on the surface of the portion of the P-type well region 323 excluding the source region 325 and the drain region 326 via a gate insulating film 328 with a thickness of several hundred angstroms. The gate wiring 335 is made of polysilicon deposited by CVD to a thickness of 3000 Å to 5000 Å. These P-MOS 320 and N-MOS 321 constitute a C-MOS logic.

In the P-type well region 323, an N-MOS transistor 330 for driving an electrothermal conversion element (heating resistance element) is formed in a portion different from the N-MOS 321. As shown in FIG. The N-MOS transistor 330 is composed of a source region 332 and a drain region 331 partially formed in the surface layer of the P-type well region 323 by steps such as impurity introduction and diffusion, a gate wiring 333, and the like. A gate wiring 333 is deposited on the surface of a portion of the P-type well region 323 excluding the source region 332 and the drain region 331 via a gate insulating film 328 .

In this example, an N-MOS transistor 330 is used as a driving transistor for the electrothermal transducer. However, the drive transistor may be any transistor that has the ability to individually drive a plurality of electrothermal conversion elements and that can obtain the fine structure described above. Not limited. Also, in this example, the electrothermal conversion element and its driving transistor are formed on the same substrate, but they may be formed on separate substrates.

Between the P-MOS 320 and the N-MOS 321, and between the N-MOS 321 and the N-MOS transistor 330, an oxide film isolation region 324 is formed by field oxidation to a thickness of 5000 Å to 10000 Å. ing. Each device is isolated by this oxide film isolation region 324 . A portion of the oxide film isolation region 324 corresponding to the heat acting portion 311 functions as the first heat storage layer 334 on the silicon substrate 304 .

An interlayer insulating film 336 made of a PSG film or a BPSG film having a thickness of about 7000 Å is formed on the surface of each element of the P-MOS 320, N-MOS 321 and N-MOS transistor 330 by CVD. After the interlayer insulating film 336 is flattened by heat treatment, an Al electrode 337 serving as a first wiring layer is formed via a contact hole penetrating the interlayer insulating film 336 and the gate insulating film 328 . An interlayer insulating film 338 made of an SiO2 film with a thickness of 10000 Å to 15000 Å is formed on the surfaces of the interlayer insulating film 336 and the Al electrode 337 by plasma CVD. A resistive layer 307 made of a TaSiN film having a thickness of about 500 .ANG. The resistance layer 307 is electrically connected to the Al electrode 337 near the drain region 331 through a through hole formed in the interlayer insulating film 338 . Al wiring 308 is formed on the surface of the resistance layer 307 as a second wiring layer serving as wiring to each electrothermal conversion element. The wiring 308, the resistance layer 307, and the protective layer 309 on the surface of the interlayer insulating film 338 are made of a 3000 Å thick SiN film formed by plasma CVD. The anti-cavitation film 310 deposited on the surface of the protective layer 309 is made of at least one metal selected from Ta, Fe, Ni, Cr, Ge, Ru, Zr, Ir, etc., and is a thin film with a thickness of about 2000 Å. consists of Various materials other than TaSiN, such as TaN _0.8 , CrSiN, TaAl, and WSiN, can be used for the resistive layer 307 as long as they can cause film boiling in a liquid.

FIGS. 6A and 6B are diagrams showing how film boiling occurs when a predetermined voltage pulse is applied to the heating element 10. FIG. Here, the case of film boiling under atmospheric pressure is shown. In FIG. 6A, the horizontal axis indicates time. The vertical axis of the lower graph indicates the voltage applied to the heating element 10, and the vertical axis of the upper graph indicates the volume and internal pressure of the film boiling bubbles 13 generated by film boiling. On the other hand, FIG. 6(b) shows how the film boiling bubbles 13 correspond to timings 1 to 3 shown in FIG. 6(a). Each state will be described below in chronological order.

Before the voltage is applied to the heating element 10, the inside of the chamber 301 is maintained at substantially atmospheric pressure. When a voltage is applied to the heating element 10, film boiling occurs in the liquid in contact with the heating element 10, and the generated bubbles (hereinafter referred to as film boiling bubbles 13) expand due to the high pressure acting from the inside (timing 1). . The foaming pressure at this time is considered to be about 8 to 10 MPa, which is close to the saturated vapor pressure of water.

The voltage application time (pulse width) is about 0.5 μsec to 10.0 μsec. However, inside the film boiling bubble 13 , the negative pressure generated along with the expansion gradually increases and acts in the direction of shrinking the film boiling bubble 13 . The volume of the film boiling bubble 13 reaches its maximum at timing 2 when the inertial force and the negative pressure are balanced, and then rapidly shrinks due to the negative pressure.

When the film boiling bubble 13 disappears, the film boiling bubble 13 disappears not in the entire surface of the heating element 10 but in one or more very small areas. Therefore, in the heating element 10, a force larger than that generated at the time of foaming shown at timing 1 is generated in a very small area where the film boiling bubbles 13 disappear (timing 3).

Generation, expansion, contraction and disappearance of the film boiling bubbles 13 as described above are repeated each time a voltage pulse is applied to the heating element 10, and a new UFB 11 is generated each time.

Next, how the UFB 11 is generated in each process of generation, expansion, contraction and disappearance of the film boiling bubbles 13 will be described in more detail.

7A to 7D are diagrams showing how the UFB 11 is generated as the film boiling bubbles 13 are generated and expanded. FIG. 7A shows the state before a voltage pulse is applied to the heating element 10. FIG. Inside the chamber 301, the liquid W mixed with the gas-dissolved liquid 3 is flowing.

FIG. 7(b) shows how a voltage is applied to the heating element 10 and the film boiling bubbles 13 are generated uniformly over almost the entire area of the heating element 10 in contact with the liquid W. FIG. When a voltage is applied, the surface temperature of the heating element 10 rises rapidly at a rate of 10° C./μsec or more, and when it reaches approximately 300° C., film boiling occurs and film boiling bubbles 13 are generated.

After that, the surface temperature of the heating element 10 rises to about 600 to 800° C. during application of the pulse, and the liquid around the film boiling bubble 13 is also rapidly heated. In the drawing, a region of the liquid located around the film boiling bubbles 13 and rapidly heated is shown as an unfoamed high-temperature region 14 . The gas-dissolved liquid 3 contained in the unfoamed high-temperature region 14 exceeds the thermal solubility limit and precipitates to become UFB. The deposited bubbles have a diameter of about 10 nm to 100 nm and have a high gas-liquid interfacial energy. Therefore, it floats in the liquid W while maintaining its independence without disappearing in a short time. In the present embodiment, such bubbles generated by thermal action during expansion of film boiling bubbles 13 are referred to as first UFB 11A.

FIG. 7C shows the expansion process of the film boiling bubbles 13 . Even after the application of the voltage pulse to the heating element 10 ends, the film boiling bubbles 13 continue to expand due to the inertia of the force obtained when they are generated, and the non-bubbled high-temperature regions 14 also move and diffuse due to inertia. That is, in the process in which the film boiling bubbles 13 expand, the gas-dissolved liquid 3 contained in the unfoamed high-temperature region 14 is newly precipitated as bubbles to form the first UFB 11A.

FIG. 7(d) shows a state in which the film boiling bubble 13 has reached its maximum volume. The film boiling bubble 13 expands due to inertia, but the negative pressure inside the film boiling bubble 13 gradually increases with the expansion, and acts as a negative pressure to contract the film boiling bubble 13 . Then, when this negative pressure balances with the inertial force, the volume of the film boiling bubbles 13 reaches its maximum, and thereafter begins to contract.

8A to 8C are diagrams showing how the UFB 11 is generated as the film boiling bubbles 13 contract. FIG. 8(a) shows a state in which the film boiling bubbles 13 have started contracting. Even if the film boiling bubble 13 starts contracting, the surrounding liquid W still has an inertial force in the expanding direction. Therefore, the inertial force acting in the direction away from the heating element 10 and the force directed toward the heating element 10 due to the contraction of the film boiling bubble 13 act on the extreme periphery of the film boiling bubble 13, resulting in a decompressed region. Become. In the drawing, such a region is indicated as an unfoamed negative pressure region 15. FIG.

The gas-dissolved liquid 3 contained in the unfoamed negative pressure region 15 exceeds the pressure solubility limit and precipitates as bubbles. The precipitated bubbles have a diameter of about 100 nm, and do not disappear in a short period of time and float in the liquid W while maintaining their independence. In the present embodiment, the bubbles deposited by the pressure action when the film boiling bubbles 13 contract in this manner are referred to as second UFB 11B.

FIG. 8(b) shows the shrinking process of the film boiling bubble 13. FIG. The speed at which the film boiling bubbles 13 shrink is accelerated by the negative pressure, and the unfoamed negative pressure region 15 also moves with the contraction of the film boiling bubbles 13 . That is, in the process of contraction of the film boiling bubbles 13, the gas-dissolved liquid 3 at the location through which the unfoamed negative pressure region 15 passes is deposited one after another to form the second UFB 11B.

FIG. 8(c) shows the state just before the film boiling bubble 13 disappears. The accelerated contraction of the film boiling bubbles 13 also increases the moving speed of the surrounding liquid W, but pressure loss occurs due to the flow path resistance in the chamber 301 . As a result, the area occupied by the unfoamed negative pressure area 15 becomes even larger, and a large number of second UFBs 11B are generated.

FIGS. 9A to 9C are diagrams showing how UFB is generated by reheating the liquid W when the film boiling bubbles 13 contract. FIG. 9A shows a state in which the surface of the heating element 10 is covered with shrinking film boiling bubbles 13 .

FIG. 9(b) shows a state in which the shrinkage of the film boiling bubble 13 progresses and a part of the surface of the heating element 10 is in contact with the liquid W. FIG. At this time, heat remains on the surface of the heating element 10 to such an extent that film boiling does not occur even when the liquid W comes into contact with the surface. In the figure, the area of the liquid that is heated by contact with the surface of the heating element 10 is shown as an unfoamed reheating area 16 . Although film boiling does not occur, the gas-dissolved liquid 3 contained in the unfoamed reheating region 16 is precipitated beyond the thermal solubility limit. In the present embodiment, bubbles generated by reheating the liquid W when the film boiling bubbles 13 contract in this manner are referred to as third UFB 11C.

FIG. 9(c) shows a state in which the shrinkage of the film boiling bubbles 13 has progressed further. As the film boiling bubbles 13 become smaller, the area of the heat generating element 10 in contact with the liquid W becomes larger, so the third UFB 11C is generated until the film boiling bubbles 13 disappear.

FIGS. 10(a) and 10(b) are diagrams showing how UFB is generated by an impact (so-called cavitation) when the film boiling bubbles 13 generated by film boiling are destroyed. FIG. 10(a) shows a state immediately before the film boiling bubble 13 disappears. The film boiling bubbles 13 are rapidly contracted by the internal negative pressure, and are surrounded by the non-foamed negative pressure region 15 .

FIG. 10(b) shows the state immediately after the film boiling bubble 13 disappears at the point P. FIG. When the film boiling bubble 13 disappears, the acoustic wave spreads concentrically with the point P as a starting point due to the impact. Acoustic waves are a general term for elastic waves that propagate regardless of gas, liquid, or solid. be done.

In this case, the gas-dissolved liquid 3 contained in the unfoamed negative pressure region 15 is resonated by the shock wave when the film boiling bubbles 13 disappear, and undergoes a phase transition exceeding the pressure solubility limit at the timing when the low pressure surface 17B passes. . That is, at the same time when the film boiling bubbles 13 disappear, a large number of bubbles are precipitated in the non-bubbled negative pressure region 15 . In this embodiment, a bubble generated by a shock wave when the film boiling bubble 13 disappears is called a fourth UFB 11D.

A fourth UFB 11D generated by a shock wave when the film boiling bubble 13 is destroyed suddenly appears in a very narrow film-like region in a very short time (1 μs or less). The diameter is significantly smaller than the first to third UFBs, and the gas-liquid interfacial energy is higher than the first to third UFBs. Therefore, it is considered that the fourth UFB 11D has different properties and produces different effects from those of the first to third UFBs 11A to 11C.

In addition, since the fourth UFB 11D is generated uniformly throughout the concentric spherical region where the shock wave propagates, it uniformly exists within the chamber 301 from the time of generation. At the timing when the fourth UFB 11D is generated, many first to third UFBs already exist, but the existence of these first to third UFBs does not greatly affect the generation of the fourth UFB 11D. do not have. Also, the generation of the fourth UFB 11D does not cause the first to third UFBs to disappear.

As described above, the UFB 11 is generated in a plurality of stages from the generation of the film boiling bubbles 13 by the heat generated by the heating element 10 to the disappearance of the bubbles. In the above example, an example was shown until the film boiling bubbles 13 disappeared, but the present invention is not limited to this in order to generate UFB. For example, by communicating with the atmosphere before the generated film boiling bubbles 13 disappear, UFB can be generated even when the film boiling bubbles 13 are not exhausted.

Next, residual characteristics of UFB will be described. The higher the temperature of the liquid, the lower the dissolution properties of the gaseous components, and the lower the temperature, the higher the dissolution properties of the gaseous components. That is, the higher the temperature of the liquid, the more likely the phase transition of dissolved gaseous components is promoted, and the more easily the UFB is generated. The temperature of the liquid and the solubility of the gas are in an inversely proportional relationship. As the temperature of the liquid rises, the gas exceeding the saturation solubility becomes bubbles and precipitates in the liquid.

Therefore, when the temperature of the liquid rises sharply from room temperature, the dissolution characteristics suddenly drop, and UFB begins to be generated. Then, as the temperature rises, the thermal dissolution characteristics decrease, resulting in a situation in which a large amount of UFB is generated.

Conversely, when the temperature of the liquid drops from room temperature, the dissolution properties of the gas increase and the UFB produced tends to liquefy. However, such temperatures are well below ambient temperature. Furthermore, even if the temperature of the liquid drops, the UFB once generated has a high internal pressure and a high gas-liquid interfacial energy, so the possibility of a pressure high enough to break the gas-liquid interface is extremely low. That is, the UFB once produced does not disappear easily as long as the liquid is stored at normal temperature and normal pressure.

In this embodiment, the first UFB 11A described in FIGS. 7A to 7C and the third UFB 11C described in FIGS. It can be said that the UFB is generated using

On the other hand, in the relationship between liquid pressure and dissolution characteristics, the higher the liquid pressure, the higher the gas dissolution characteristics, and the lower the pressure, the lower the dissolution characteristics. That is, the lower the pressure of the liquid, the more likely the phase transition of the gas-dissolved liquid dissolved in the liquid to the gas is promoted, and the UFB is likely to be generated. When the pressure of the liquid is lowered from normal pressure, the dissolution characteristics drop sharply and UFB begins to be generated. As the pressure decreases, the pressure dissolution characteristics decrease, resulting in a situation in which a large amount of UFB is generated.

Conversely, when the pressure of the liquid rises from normal pressure, the dissolution properties of the gas rise and the produced UFB tends to liquefy. However, such a pressure is sufficiently higher than the atmospheric pressure, and even if the pressure of the liquid rises, the UFB once generated has a high internal pressure and a high gas-liquid interfacial energy, which destroys the gas-liquid interface. It is extremely unlikely that such high pressure would act. That is, the UFB once produced does not disappear easily as long as the liquid is stored at normal temperature and normal pressure.

In this embodiment, the second UFB 11B described in FIGS. 8A to 8C and the fourth UFB 11D described in FIGS. It can be said that the UFB is generated using

Although the first to fourth UFBs having different generating factors have been individually described above, the above-described generating factors occur simultaneously and frequently in association with the phenomenon of film boiling. Therefore, at least two types of UFBs among the first to fourth UFBs may be generated simultaneously, and these generation factors may cooperate with each other to generate UFBs. However, it is common that all generation factors are caused by the film boiling phenomenon. Hereinafter, in this specification, the method of generating UFB by utilizing film boiling accompanying rapid heat generation is referred to as T-UFB (Thermal-Ultra Fine Bubble) generating method. Further, the UFB produced by the T-UFB producing method is called T-UFB, and the liquid containing T-UFB produced by the T-UFB producing method is called T-UFB liquid.

Most of the bubbles generated by the T-UFB generation method are 1.0 μm or less, and millibubbles and microbubbles are difficult to generate. That is, according to the T-UFB generation method, only UFBs are efficiently generated. In addition, the T-UFB produced by the T-UFB production method has a higher gas-liquid interfacial energy than the UFB produced by the conventional method, and does not easily disappear as long as it is stored at normal temperature and normal pressure. Furthermore, even if a new T-UFB is generated by a new film boiling, the previously generated T-UFB will not disappear due to the impact. In other words, it can be said that the number and concentration of T-UFB contained in the T-UFB liquid have hysteresis characteristics with respect to the number of occurrences of film boiling in the T-UFB liquid. In other words, the concentration of T-UFB contained in the T-UFB liquid can be adjusted by controlling the number of heating elements arranged in the T-UFB generation unit 300 and the number of voltage pulse applications to the heating elements.

Refer to FIG. 1 again. After the T-UFB liquid W having the desired UFB concentration is generated in the T-UFB generation unit 300 , the UFB liquid W is supplied to the post-treatment unit 400 .

11A to 11C are diagrams showing configuration examples of the post-processing unit 400 of this embodiment. The post-treatment unit 400 of the present embodiment removes impurities contained in the UFB liquid W in stages in the order of inorganic ions, organic substances, and insoluble solids. The post-treatment unit as irradiation means for irradiating the oxygen-containing UFB liquid with ultraviolet rays will be described later.

FIG. 11(a) shows a first post-treatment mechanism 410 for removing inorganic ions. The first post-treatment mechanism 410 includes an exchange container 411 , a cation exchange resin 412 , a liquid introduction path 413 , a water collection pipe 414 and a liquid outlet path 415 . The exchange container 411 contains a cation exchange resin 412 . The UFB liquid W generated by the T-UFB generation unit 300 is injected into the exchange container 411 via the liquid introduction path 413 and absorbed by the cation exchange resin 412, where cations as impurities are removed. . Such impurities include metal materials separated from the element substrate 12 of the T-UFB generation unit 300, such as SiO ₂ , SiN, SiC, Ta, Al ₂ O ₃ , Ta ₂ O ₅ and Ir. be done.

The cation exchange resin 412 is a synthetic resin in which a functional group (ion exchange group) is introduced into a polymer base having a three-dimensional network structure. presenting. A styrene-divinylbenzene copolymer is generally used as the polymer base, and methacrylic acid-based and acrylic acid-based functional groups can be used as the functional group. However, the above materials are only examples. Various changes can be made to the above materials as long as the desired inorganic ions can be effectively removed. The UFB liquid W absorbed by the cation exchange resin 412 and from which the inorganic ions have been removed is collected by the water collection pipe 414 and sent to the next step through the liquid lead-out path 415 .

FIG. 11(b) shows a second post-treatment mechanism 420 for removing organics. The second post-treatment mechanism 420 includes a container 421 , a filtration filter 422 , a vacuum pump 423 , a valve 424 , a liquid introduction path 425 , a liquid extraction path 426 and an air suction path 427 . The inside of the storage container 421 is divided into upper and lower regions by a filtration filter 422 . The liquid introduction path 425 connects to the upper area of the upper and lower areas, and the air suction path 427 and the liquid lead-out path 426 connect to the lower area. When the vacuum pump 423 is driven with the valve 424 closed, the air in the container 421 is discharged through the air suction path 427, the pressure inside the container 421 becomes negative, and the UFB liquid W is introduced from the liquid introduction path 425. is introduced. Then, the UFB liquid W from which impurities have been removed by the filtration filter 422 is stored in the container 421 .

Impurities removed by the filtration filter 422 include organic materials that may be mixed in the tubes and units, such as organic compounds containing silicon, siloxane, and epoxy. Filter membranes that can be used for the filtration filter 422 include a sub-μm mesh filter that can remove even bacteria and an nm mesh filter that can remove viruses.

After a certain amount of the UFB liquid W is stored in the container 421, the vacuum pump 423 is stopped and the valve 424 is opened. be. Here, the vacuum filtration method is used as a method for removing organic impurities, but gravity filtration or pressure filtration can also be used as a filtration method using a filter.

FIG. 11(c) shows a third post-treatment mechanism 430 for removing undissolved solids. The third post-treatment mechanism 430 comprises a sedimentation container 431 , a liquid introduction channel 432 , a valve 433 and a liquid outlet channel 434 .

First, with the valve 433 closed, a predetermined amount of the UFB liquid W is stored in the precipitation container 431 from the liquid introduction path 432 and left for a while. During this time, solids contained in the UFB liquid W settle to the bottom of the sedimentation container 431 due to gravity. Among the bubbles contained in the UFB liquid, relatively large bubbles such as microbubbles also rise to the liquid surface due to buoyancy and are removed from the UFB liquid. When the valve 433 is opened after a sufficient amount of time has passed, the UFB liquid W from which solid matter and large-sized bubbles have been removed is sent to the recovery unit 500 through the liquid lead-out path 434 .

Please refer to FIG. 1 again. The T-UFB liquid W from which impurities have been removed in the post-processing unit 400 may be sent to the recovery unit 500 as it is, or may be returned to the dissolving unit 200 again. In the latter case, the dissolved gas concentration of the T-UFB liquid W, which has decreased due to the production of T-UFB, can be replenished to the saturation state in the dissolving unit 200 again. Further, if new T-UFB is generated by the T-UFB generation unit 300, the concentration of UFB in the T-UFB liquid can be further increased based on the characteristics described above. That is, the UFB content concentration can be increased by the number of circulations through the dissolving unit 200, the T-UFB generation unit 300, and the post-treatment unit 400, and after the desired UFB content concentration is obtained, the UFB liquid W is added. Liquid can be sent to the recovery unit 500 .

Here, the effect of returning the generated T-UFB liquid W to the dissolving unit 200 again will be briefly described according to the details of verification specifically verified by the present inventors. First, in the T-UFB generation unit 300, 10,000 heating elements 10 are arranged on the element substrate 12. FIG. Industrial pure water was used as the liquid W, and was made to flow in the chamber 301 of the T-UFB generation unit 300 at a flow rate of 1.0 liter/hour. In this state, a voltage pulse with a voltage of 24 V and a pulse width of 1.0 μs was applied to each heating element at a driving frequency of 10 KHz.

When the generated T-UFB liquid W is recovered by the recovery unit 500 without being returned to the dissolving unit 200, that is, when the number of circulations is set to 1, the T-UFB liquid W recovered by the recovery unit 500 has the following effects: 1. 3.6 billion UFBs per 0 mL were identified. On the other hand, when the operation of returning the T-UFB solution W to the dissolution unit 200 is performed 9 times, that is, when the number of circulations is 10, the T-UFB solution W recovered by the recovery unit 500 contains 36 billion UFBs have been confirmed. That is, it was confirmed that the UFB content concentration increased in proportion to the number of circulations. The number density of UFB as described above is obtained by counting UFB41 having a diameter of less than 1.0 μm contained in a predetermined volume of UFB liquid W using a measuring instrument (model number SALD-7500) manufactured by Shimadzu Corporation. did.

The recovery unit 500 recovers and stores the UFB liquid W sent from the post-treatment unit 400 . The T-UFB liquid recovered by the recovery unit 500 becomes a high-purity UFB liquid from which various impurities are removed.

In the collection unit 500, several stages of filtering may be performed to classify the UFB liquid W according to T-UFB size. In addition, since the T-UFB liquid W obtained by the T-UFB production method is expected to have a temperature higher than normal temperature, the recovery unit 500 may be provided with cooling means. Note that such a cooling means may be provided in a part of the post-processing unit 400 .

The above is the outline of the UFB liquid generation apparatus 1, but the plurality of units shown in the figure can of course be changed, and it is not necessary to prepare all of them. Depending on the type of liquid W and gas G to be used and the purpose of use of the T-UFB liquid to be generated, some of the units described above may be omitted, or another unit may be added in addition to the units described above. may

For example, when the gas contained in the UFB is the atmosphere, the degassing unit 100 and the dissolving unit 200 can be omitted. Conversely, if it is desired to include multiple types of gases in the UFB, additional dissolving units 200 may be added.

Also, the functions of several units shown in FIG. 1 can be combined into one unit. For example, the melting unit 200 and the T-UFB generation unit 300 can be integrated by disposing the heating element 10 in the melting container 201 shown in FIGS. 3(a) and 3(b). Specifically, an electrode type T-UFB module is incorporated in a gas dissolving container (high pressure chamber), and a plurality of heaters arranged in the module are driven to generate film boiling. In this way, a T-UFB containing the gas can be produced while dissolving the gas in one unit. In this case, by arranging the T-UFB module at the bottom of the gas dissolving vessel, the heat generated by the heater causes Marangoni convection, and the liquid in the vessel can be heated to some extent without providing circulation/stirring means. Allow to stir.

11(a) to 11(c) for removing impurities may be provided upstream of the T-UFB generation unit 300 as part of the pretreatment unit. It may be provided both downstream. When the liquid supplied to the UFB liquid generator is tap water, rain water, contaminated water, or the like, the liquid may contain organic or inorganic impurities. If the liquid W containing such impurities is supplied to the T-UFB generation unit 300, there is a risk that the heating elements 10 will be degraded or salting out will occur. By providing a mechanism as shown in FIGS. 11(a) to 11(c) upstream of the T-UFB generation unit 300, the impurities as described above are removed in advance, and the UFB liquid with higher purity is produced. Efficient generation is possible.

In particular, when the impurity removal unit using the ion exchange resin shown in FIG. 11(a) is provided in the pretreatment unit, the placement of the anion exchange resin contributes to the efficient generation of the T-UFB liquid. This is because it has been confirmed that the ultra-fine bubbles generated by the T-UFB generation unit 300 have a negative charge. Therefore, by removing impurities having the same negative charge in the pretreatment unit, a T-UFB liquid with high purity can be produced. As the anion exchange resin used here, both a strongly basic anion exchange resin having a quaternary ammonium group and a weakly basic anion exchange resin having a primary to tertiary amine group are suitable. Which of these is appropriate depends on the type of liquid used. Normally, when tap water or pure water is used as the liquid, the latter weakly basic anion exchange resin alone can sufficiently perform the function of removing impurities.

<< Liquid that can be used for T-UFB liquid >>
Here, the liquid W contained in the T-UFB liquid will be described. Examples of the liquid W that can be used in the present embodiment include pure water, ion-exchanged water, distilled water, physiologically active water, magnetically active water, lotion, tap water, seawater, river water, sewage water, lake water, groundwater, Examples include rainwater. Mixed liquids containing these liquids can also be used. A mixed solvent of water and a water-soluble organic solvent can also be used. The water-soluble organic solvent to be mixed with water is not particularly limited, but specific examples include the following. Alkyl alcohols having 1 to 4 carbon atoms such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol and tert-butyl alcohol. amides such as N-methyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N,N-dimethylformamide and N,N-dimethylacetamide; ketones or ketoalcohols such as acetone and diacetone alcohol; cyclic ethers such as tetrahydrofuran and dioxane; ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol; 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 3-methyl-1,5- glycols such as pentanediol, diethylene glycol, triethylene glycol and thiodiglycol; Polyethylene glycol such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether. lower alkyl ethers of hydric alcohols; polyalkylene glycols such as polyethylene glycol and polypropylene glycol; triols such as glycerin, 1,2,6-hexanetriol and trimethylolpropane; These water-soluble organic solvents may be used alone or in combination of two or more.

<<Gas that can be used for T-UFB liquid>>
Next, gas contained in the T-UFB liquid will be described. Gases that can be used in this embodiment include oxygen in the T-UFB liquid before ultraviolet irradiation and ozone in the T-UFB liquid after ultraviolet irradiation. That is, in the present embodiment, it is sufficient that oxygen is changed to ozone by irradiating the oxygen-containing UFB liquid with ultraviolet rays.

Gases that can be introduced into the dissolving unit 200 include, in addition to oxygen, hydrogen, helium, nitrogen, methane, fluorine, neon, carbon dioxide, ozone, argon, chlorine, ethane, propane, air, and the like. It may also be a mixed gas containing some of the above. Furthermore, the dissolution unit 200 does not necessarily have to dissolve a substance in a gaseous state, and may dissolve a liquid or solid composed of desired components into the liquid W. FIG. Dissolution in this case may be spontaneous dissolution, dissolution by application of pressure, hydration by ionization, ionization, or dissolution accompanied by chemical reaction.

<<UV irradiation>>
Here, ultraviolet irradiation will be described. In the present embodiment, first, a liquid in which a gas containing oxygen is dissolved is subjected to film boiling by means of a heating unit to generate an oxygen-containing ultra-fine bubble liquid (oxygen-containing UFB liquid). Then, an ozone-containing UFB liquid is generated by irradiating the oxygen-containing UFB liquid with ultraviolet rays.

A well-known thing can be used as an ultraviolet-irradiation apparatus. For example, a typical example is a mercury lamp using quartz as the glass, but similar effects can also be obtained with recent mercury-free ozone lamps and excimer lamps using a desired gas as the discharge gas. In particular, the ultraviolet irradiation device is preferably an excimer lamp that uses xenon as a discharge gas and has an emission wavelength of 172 nm. In addition, it is preferable to use a material having ozone resistance as a liquid-contacting member for the ozone-containing UFB liquid after ultraviolet irradiation. As the ozone-resistant material, it is preferable to use titanium as a metal, fluorine-based polymer (PFA, PTFE, etc.) as a resin, and quartz as a glass.

After the oxygen-containing UFB liquid is generated, the oxygen-containing UFB liquid is irradiated with ultraviolet rays by an ultraviolet irradiation device, and when oxygen molecules absorb photons with a wavelength of 184.9 nm, they dissociate into oxygen atoms, and the oxygen atoms combine with oxygen molecules to form ozone. is generated to obtain an ozone-containing UFB liquid.

Although the details of why the ozone-containing UFB liquid obtained in this manner can be stored for a long time at a high concentration are unknown, the present inventors presume the reason as follows.

In the dissolution unit, the gas dissolves in the liquid according to Henry's Law, depending on the rate of introduction of the gas and the solubility of the gas in the liquid. It is speculated that the UFB contained in the liquid maintains an equilibrium state between the gas in the UFB and the gas dissolved in the liquid. Therefore, if the ozone in the liquid is consumed, it is assumed that ozone is supplied from the UFB side to maintain the equilibrium state, and as a result, the ozone concentration in the liquid is maintained for a long period of time.

FIG. 12 is a schematic diagram showing an ozone-containing ultra-fine bubble liquid generator 700. As shown in FIG. The dissolution unit 200 and the T-UFB generation unit 300 are connected to each other by piping. The T-UFB generation unit 300 and the post-processing unit 400 are connected to each other by piping. The liquid is transferred by a pump (not shown) arranged in the middle of the pipe.

The irradiation of ultraviolet rays from the ultraviolet lamp (ultraviolet irradiation device) 600 can be generated by irradiation in the liquid or by irradiation from the outside of the liquid. In addition, the UFB liquid to which the ultraviolet rays are irradiated may be in a stopped water state or a flowing water state, and in the flowing water state, it is possible to be in any state of circulation or agitation.

After a gas containing oxygen (eg, air) is dissolved in a liquid in the dissolving unit 200, UFB is generated in the T-UFB generation unit 300 to obtain a UFB liquid containing oxygen. Thereafter, in the post-treatment unit 400, the obtained UFB liquid containing oxygen is irradiated with ultraviolet rays using the ultraviolet lamp 600 to ozonize the oxygen, thereby obtaining an ozone-containing UFB liquid. In such an ozone-containing UFB liquid generator, after the oxygen-containing UFB liquid is generated, the oxygen is ozonized by irradiation with ultraviolet rays. Therefore, it is not necessary to use a member that guarantees ozone resistance as a wetted member up to the UFB generation step, and the cost reduction of the apparatus can be expected. In the configuration example of FIG. 12, the wetted members of the dissolution unit 200, the T-UFB generation unit 300, the piping connecting them, and the piping connecting the T-UFB generation unit 300 and the post-treatment unit 400 , there is no need to use a member that guarantees ozone resistance.

Thus, an aqueous liquid containing oxygen as a dissolved gas is film-boiling to generate an oxygen-containing UFB liquid, and the generated oxygen-containing UFB liquid is irradiated with ultraviolet rays. Accordingly, it is possible to provide an ozone-containing UFB liquid generation apparatus and an ozone-containing UFB liquid generation method that can efficiently generate an ozone-containing UFB liquid that can be stored for a long time at a high concentration.

(Second embodiment)
A second embodiment of the present invention will be described below with reference to the drawings. Since the basic configuration of this embodiment is the same as that of the first embodiment, the characteristic configuration will be described below.

FIG. 13 is a schematic diagram showing an ozone-containing UFB liquid generating apparatus 800 of this embodiment. In the ozone-containing UFB liquid generation apparatus 800, after the gas containing oxygen is dissolved in the liquid in the dissolving unit 200, the flying droplets containing UFB generated in the T-UFB generation unit 300 are irradiated with the ultraviolet lamp 600 from the outer periphery. to generate an ozone-containing UFB liquid. The T-UFB generation unit 300 in this embodiment has an ejection opening for ejecting droplets, and ejects droplets containing UFB from the ejection opening. Further, the ultraviolet lamp 600 in this embodiment is a ring-shaped lamp, and droplets containing oxygen-containing UFB are caused to fly inside the ring of the ring-shaped ultraviolet lamp to irradiate the droplets with ultraviolet rays. In the ozone-containing UFB liquid generating apparatus 800, droplets are discharged from the liquid lead-out path 303 shown in FIG. Recover the ozone-containing UFB fluid. The recovery unit 500 is preferably made of ozone-resistant material such as titanium for metal, fluorine-based polymer (PFA, PTFE, etc.) for resin, and quartz for glass. In this embodiment, the recovery unit 500 may be a member that guarantees ozone resistance.

In this embodiment, an example of using a ring-shaped ultraviolet lamp as the ultraviolet lamp 600 has been described, but the shape of the ultraviolet irradiation device is not limited to this. Any shape is acceptable as long as the flying droplets containing UFB can be irradiated with ultraviolet rays.

(Third Embodiment)
A third embodiment of the present invention will be described below with reference to the drawings. Since the basic configuration of this embodiment is the same as that of the first embodiment, the characteristic configuration will be described below.

FIG. 14 is a schematic diagram showing an ozone-containing UFB liquid generating apparatus 900 of this embodiment. In the ozone-containing UFB liquid generation apparatus 900, after the gas containing oxygen is dissolved in the liquid in the dissolving unit 200, the flying droplets containing UFB generated in the T-UFB generation unit 300 are exposed to the ultraviolet lamp 600 from the outer periphery. to obtain droplets of the ozone-containing UFB liquid. The T-UFB generation unit 300 in this embodiment has an ejection opening for ejecting droplets, and ejects droplets containing UFB from the ejection opening. Further, the ultraviolet lamp 600 in this embodiment is a ring-shaped lamp, and droplets containing oxygen-containing UFB are caused to fly inside the ring of the ring-shaped ultraviolet lamp to irradiate the droplets with ultraviolet rays. The ozone-containing UFB liquid generator 900 is intended to make the obtained ozone-containing UFB liquid into a mist and spray it in space. In such an ozone-containing UFB liquid generating apparatus 900 , the ozone-containing UFB liquid is not stored after the ozone-containing UFB liquid is generated by irradiating ultraviolet rays from the ultraviolet lamp 600 . Therefore, there is no need to use a member that guarantees ozone resistance for any member, and cost reduction of the device can be expected.

In this embodiment, an example of using a ring-shaped ultraviolet lamp as the ultraviolet lamp 600 has been described, but the shape of the ultraviolet irradiation device is not limited to this. Any shape is acceptable as long as the flying droplets containing UFB can be irradiated with ultraviolet rays.

(Other embodiments)
In the above embodiment, an example in which the dissolving unit 200 and the T-UFB generating unit 300 are connected by piping has been described, but the present invention is not limited to this. The dissolution unit 200 and the T-UFB generation unit 300 may be constructed integrally. Further, the ozone-containing UFB liquid generating apparatus may not include the dissolving unit 200 . A liquid in which a gas containing oxygen is dissolved in advance may be injected into the T-UFB generation unit 300 to generate an oxygen-containing UFB liquid, and the generated oxygen-containing UFB liquid may be irradiated with ultraviolet rays.

Hereinafter, using the ozone-containing UFB liquid generation apparatus 700 shown in FIG. 12, the ozone-containing UFB liquid was generated by changing each generation condition, and the results of verification of the generated ozone-containing UFB liquid will be described. .

In the T-UFB generation unit 300, 10,000 heating elements were arranged on one substrate, and a total of 10 substrates were mounted in series. A pulse signal (pulse width: 1.0 μs, voltage: 24 V) was applied to these heating elements at a driving frequency of 20 kHz, water was supplied according to the conditions of each example, and the flow velocity V was set to 1.0 L. /h, various UFB liquids were experimentally produced. The surface temperature of the heating element was measured from changes in electric resistance by setting a thermocouple on the heating element. The ozone concentration in the prototype UFB liquid was measured by a predetermined color reaction.

Ozone was generated by irradiating ultraviolet rays from an ultraviolet lamp 600 to various kinds of UFB liquids produced as a trial. A 0.3 A, 4.1 W low-pressure mercury lamp containing emission wavelengths of 184.9 nm and 253.7 nm was used as the ultraviolet lamp 600, and ultraviolet rays were irradiated for 5 minutes. Ozone concentration was measured by a given color reaction.

For measurement of UFB, a measuring instrument (model number SALD-7500) manufactured by Shimadzu Corporation was used to measure the average particle size and concentration of UFB contained in the UFB liquid.

(Example 1)
Using water in which 18 ppm of oxygen is dissolved, an oxygen-containing UFB liquid is generated at a surface temperature of the heating element of 305°C (liquid temperature: 25°C), and the generated oxygen-containing UFB liquid is irradiated with an emission wavelength of 185 nm from a low-pressure mercury lamp. to obtain an ozone-containing UFB liquid. The amount of impurities mixed in the obtained ozone-containing UFB liquid was judged to be superior or inferior to contamination from the results of chemical oxygen demand (COD) measurement.

As an effect of the ozone-containing UFB liquid, the sterilization function is well known. The same volume of ozone-containing water was added to an aqueous solution containing approximately 100 cells/ml of Escherichia coli and Staphylococcus aureus, and the bactericidal effect was verified. Initial and post-verification bacterial count evaluations were carried out using the product name "Sanai Biochecker TTC" (manufactured by Sanai Oil Co., Ltd.).

In addition, in order to verify the storage stability of ozone in the ozone-containing UFB liquid, the ozone concentration after one week in an environment of 5° C. was verified by color reaction.

(Example 2)
An ozone-containing UFB liquid was produced in the same manner as in Example 1, except that the liquid temperature during the production of the oxygen-containing UFB liquid was cooled to 5°C. By cooling, the surface temperature of the heating element was 295°C.

(Example 3)
An ozone-containing UFB liquid was produced in the same manner as in Example 1, except that 2 ppm of ozone was dissolved together with oxygen in the water during the production of the oxygen-containing UFB liquid.

(Example 4)
An ozone-containing UFB liquid was produced in the same manner as in Example 1, except that the gas used in producing the oxygen-containing UFB liquid was changed from oxygen to air.

(Example 5)
In Example 1, in the same manner as in Example 1, except that the ultraviolet lamp was changed from a low-pressure mercury lamp to a xenon excimer lamp with an input voltage of DC 12 V and a power consumption of 6 W, which can irradiate ultraviolet rays including an emission wavelength of 172 nm. An ozone-containing UFB fluid was produced.

(Comparative example 1)
In Example 1, a sample was prepared in the same manner as in Example 1, except that oxygen was not dissolved in water in the dissolution unit 200, and water from which oxygen dissolved in water was degassed was used. produced a liquid.

(Comparative example 2)
A sample liquid was produced in the same manner as in Example 1, except that the gas used in producing the oxygen-containing UFB liquid was changed from oxygen to nitrogen.

(Comparative Example 3)
A sample liquid was produced in the same manner as in Example 1, except that the heating element in the T-UFB generation unit 300 was not energized.

(Comparative Example 4)
A sample liquid was produced in the same manner as in Example 1, except that the post-treatment unit 400 did not irradiate ultraviolet rays.

(Comparative Example 5)
UFB production was changed to microporous rather than T-UFB production. Specifically, instead of the T-UFB generation unit 300, the gas phase and the water phase are separated through a microporous membrane, the liquid phase is circulated with a negative pressure using a suction pump, and oxygen is generated through the micropores. A sample liquid was produced in the same manner as in Example 1, except that an oxygen-containing UFB liquid was prepared by aspirating . As the microporous membrane, a filtration membrane with a molecular weight cut off of 1000 (Minimate manufactured by Nihon Pall Co., Ltd.) was used.

(Comparative Example 6)
The ozone-containing UFB liquid produced in the same manner as in Comparative Example 5 was filtered using a filtration membrane (Minimate manufactured by Nippon Pall Co., Ltd.) with a molecular weight cut off of 500, and half of the concentrated liquid was recovered to produce a sample liquid.

(Comparative Example 7)
The ozone-containing UFB liquid produced in the same manner as in Comparative Example 5 was filtered using a filtration membrane (Minimate manufactured by Nihon Pall Co., Ltd.) with a molecular weight cut off of 500, and half of the permeated liquid was collected to produce a sample liquid.

(Comparative Example 8)
UFB generation was performed by changing to a swirling flow method instead of the T-UFB generation method. Specifically, in place of the T-UFB generation unit 300, a shower head capable of generating UFB liquid (trade name: Bolina, manufactured by Tanaka Kinzoku Co., Ltd.) was used in the same manner as in Example 1. A sample liquid was produced.

Tables 1 and 2 show the evaluation results of the sample liquids produced in the above examples and comparative examples. "-" in Table 2 means that the measurement could not be performed.

(Evaluation criteria)
Contamination criteria: COD by potassium permanganate color reaction
A 0 ppm or more, less than 5 ppm B 5 ppm or more, less than 10 ppm C 10 ppm or more

Judgment criteria for bactericidal effect: Reduction rate of E. coli after 24 hours of dilution A 90% or more B 50% or more, less than 90% C less than 50%

Judgment criteria for storage stability: Ozone concentration A 1 ppm or more, B 0.1 ppm or more, less than 1 ppm, C less than 0.1 ppm due to color reaction after 1 week in an environment at 5 ° C.

As shown in Table 1, in Examples 1 to 4, it was possible to obtain substantially satisfactory evaluation results.

Claims (11)

an ultra-fine bubble generating means for generating ultra-fine bubbles by causing film boiling in a liquid in which a gas containing oxygen is dissolved by means of a heating part;
irradiating means for irradiating the liquid in which the ultra-fine bubbles are generated with ultraviolet rays;
An apparatus for generating an ozone-containing ultra-fine bubble liquid, comprising: 2. The apparatus for generating an ozone-containing ultra-fine bubble liquid according to claim 1, wherein said ultra-fine bubble generating means has an ejection port, and ejects droplets in which said ultra-fine bubbles are generated from said ejection port. 3. The apparatus for generating an ozone-containing ultra-fine bubble liquid according to claim 2, wherein the irradiation means irradiates the droplets discharged from the discharge port with ultraviolet rays. The irradiation means is ring-shaped,
4. The apparatus for generating an ozone-containing ultra-fine bubble liquid according to claim 2, wherein said ultra-fine bubble generating means discharges droplets inside said ring-shaped irradiation means. 5. The apparatus for generating an ozone-containing ultra-fine bubble liquid according to any one of claims 2 to 4, wherein the ultra-fine bubble generating means spatially sprays the liquid droplets. A storage means for storing the liquid irradiated with ultraviolet rays by the irradiation means,
5. The apparatus for generating an ozone-containing ultra-fine bubble liquid according to any one of claims 1 to 4, wherein the storage means has ozone resistance. 7. The apparatus for generating ozone-containing ultra-fine bubble liquid according to claim 6, wherein said storage means is made of at least one material selected from titanium, fluoropolymer, and quartz. 8. The apparatus for generating ozone-containing ultra-fine bubble liquid according to any one of claims 1 to 7, wherein said irradiation means irradiates ultraviolet rays including emission wavelengths of 184.9 nm and 253.7 nm. further comprising dissolving means for dissolving a gas containing oxygen in the liquid;
The ozone-containing ultra-fine bubble liquid generating apparatus according to any one of claims 1 to 8, wherein the ultra-fine bubble generating means generates ultra-fine bubbles in the liquid in which the gas containing oxygen is dissolved by the dissolving means. 10. The ozone-containing ultra-fine bubble liquid generating apparatus according to claim 9, wherein the dissolving means dissolves oxygen in the liquid. an ultra-fine bubble generating step of generating ultra-fine bubbles by causing film boiling in a liquid in which a gas containing oxygen is dissolved by means of a heating part;
an irradiation step of irradiating the liquid in which the ultra-fine bubbles are generated with ultraviolet rays;
A method for producing an ozone-containing ultra-fine bubble liquid, comprising:

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