Patent Application
20220288542
The present disclosure relates to a manufacturing apparatus of an ultra fine bubble-contained liquid.
In recent years, the technique has been developed that applies the characteristic of a fine bubble, such as a micro bubble whose diameter is the micrometer size and a nano bubble whose diameter is the nanometer size. In particular, the usefulness of an ultra fine bubble (in the following, also referred to as “UFB”) whose diameter is less than 1.0 μm has been verified in a variety of fields.
Japanese Patent No. 6118544 has disclosed a fine air bubble generation apparatus that generates fine bubbles by jetting a pressurized liquid in which gas is pressure-dissolved from a decompression nozzle. Further, Japanese Patent No. 4456176 has disclosed an apparatus that generates fine bubbles by repeating division and integration of a gas-mixed liquid using a mixing unit.
Both in the apparatus described in Japanese Patent No. 6118544 and in the apparatus described in Japanese Patent No. 4456176, in addition to the UFB whose diameter is the nanometer size, the milli bubble whose diameter is the millimeter size and the micro bubble whose diameter is the micrometer size are generated in a comparatively large amount. However, the buoyant force acts on the milli bubble and the micro bubble, and therefore, there is a tendency for them to gradually float up to the liquid surface and become extinct in long-term preservation.
On the other hand, the UFB whose diameter is the nanometer size is unlikely to be affected by the buoyant force and floats in the liquid while performing Brownian motion, and therefore, is suitable to long-term preservation. However, even the UFB is affected by the extinction of the milli bubble and the micro bubble and becomes less in number as time elapses in a case where the UFB is generated together with the milli bubble and the micro bubble or the gas-liquid interface energy is small. Consequently, despite the existence of the many FUBs at the time of generation, the number is reduced at the time of the actual utilization of the UFB and it is not possible to obtain a sufficient utilization effect.
Consequently, in view of the above-described problem, an object of one embodiment of the present invention is to provide a manufacturing apparatus of an ultra fine bubble-contained liquid that can be utilized effectively because high concentration ultra fine bubbles are maintained for a long time at the time of manufacturing of the ultra fine bubble-contained liquid.
One embodiment of the present invention is a manufacturing apparatus of an ultra fine bubble-contained liquid, which includes: a container having a gas supply port through which gas is introduced and a liquid supply port through which a liquid is introduced; and a generation unit inside the container, which is configured to cause an ultra fine bubble to occur in the liquid in which the gas is dissolved.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
In the following, an outline of a UFB generation apparatus that utilizes a film boiling phenomenon is explained.
After a certain amount of the liquid W is stored in the deaeration container 101, in a case where the decompression pump 103 is activated in the state where all the valves are closed, the gas component already vaporized is discharged and at the same time, the vaporization and discharge of the gas component dissolved in the liquid W are also facilitated. At this time, it is sufficient to reduce the internal pressure of the deaeration container 101 to about several hundred to several thousand Pa (1.0 Torr to 10.0 Torr) while checking a pressure gauge 108. The gas that is deaerated by the preprocessing unit 100 includes, for example, nitrogen, oxygen, argon, carbon dioxide and the like.
It is possible to repeatedly perform the deaeration processing explained above for the same liquid W by utilizing the liquid circulation passage 105. Specifically, in the state where the valve 109 of the liquid introduction passage 104 and a valve 110 of the liquid discharge passage 106 are closed and a valve 107 of the liquid circulation passage 105 is open, the shower head 102 is activated. Due to this, the liquid W stored in the deaeration container 101 and for which the deaeration processing has been performed once is sprayed again within the deaeration container 101 via the shower head 102. Further, by activating the decompression pump 103, the vaporization processing by the shower head 102 and the deaeration processing by the decompression pump 103 are performed repeatedly for the same liquid W. Then, each time the above-described repetition processing utilizing the liquid circulation passage 105 is performed, it is possible to reduce the gas component included in the liquid W stepwise. In a case where the liquid W deaerated to a predetermined purity is obtained, by opening the valve 110, the liquid W is sent to the dissolving unit 200 via the liquid discharge passage 106.
In
By performing the deaeration processing as above as preprocessing, in a dissolving process described later, it is possible to increase the purity and solubility for the liquid W of desired gas. Further, in the T-UFB generation unit, to be described later, it is possible to increase the purity of a desired UFB included in the liquid W. That is, by providing the preprocessing unit 100 before the dissolving unit 200 and the T-UFB generation unit 300, it is made possible to efficiently generate the UFB-contained liquid of high purity.
The liquid W supplied from the preprocessing unit 100 is supplied to the dissolving container 201 through the liquid introduction passage 204 and stored therein. On the other hand, gas G is supplied to the dissolving container 201 through the gas introduction passage 205.
In a case where a predetermined amount of the liquid W and the gas G is stored in the dissolving container 201, the pressure pump 207 is activated and the internal pressure of the dissolving container 201 is increased to about 0.5 MPa. Between the pressure pump 207 and the dissolving container 201, a safety valve 208 is arranged. Further, by rotating the rotation plate 202 in the liquid via the rotation shaft 203, the gas G supplied to the dissolving container 201 is turned into air bubbles and dissolving into the liquid W is facilitated by increasing the contact area with the liquid W. Then, the work such as this is continued until the solubility of the gas G reaches substantially the maximum saturated solubility. At this time, in order to dissolve the gas as much as possible, it may also be possible to arrange a unit configured to reduce the temperature of the liquid. Further, in a case of an insoluble gas, it is also possible to increase the internal pressure of the dissolving container 201 to 0.5 MPa or higher. In that case, it is necessary to make optimum the material and the like of the container in view of safety.
In a case where the liquid W in which the component of the gas G is dissolved in a desired concentration is obtained, the liquid W is discharged via the liquid discharge passage 206 and supplied to the T-UFB generation unit 300. At this time, a back pressure valve 209 adjusts the flow pressure of the liquid W so that the pressure at the time of supply does not become higher than necessary.
In
At the bottom surface of the chamber 301, an element substrate 12 on which a heating element 10 is provided is arranged. By applying a predetermined voltage pulse to the heating element 10, a bubble 13 (in the following, also referred to as film boiling bubble 13) generated by film boiling occurs in the area that comes into contact with the heating element 10. Then, an ultra fine bubble (UFB 11) containing the gas G is generated accompanying expansion and contraction of the film boiling bubble 13. As a result of that, from the liquid discharge passage 303, the UFB-contained liquid W in which the many UFBs 11 are included is discharged.
As shown in
On the front surface of the protective layer 309, at the portion corresponding to a heat acting portion 311, which eventually functions as the heating element 10, and on the periphery thereof, an anti-cavitation film 310 for protecting the protective layer 309 from the chemical and physical impacts accompanying heat generation of the resistant layer 307 is formed. On the front surface of the resistant layer 307, the area in which the wire 308 is not formed is the heat acting portion 311 at which the resistant layer 307 generates heat. The heat generation portion of the resistant layer 307 at which the wire 308 is not formed functions as the heating element (heater) 10. As described above, the layers in the element substrate 12 are formed sequentially on the front surface of the silicon substrate 304 by the semiconductor manufacturing technique and due to this, the silicon substrate 304 is provided with the heat acting portion 311.
The configuration shown in
The P-MOS 320 includes a source area 325 and a drain area 326, which are formed by introducing N-type or P-type impurities partially into the front layer of the N-type well area 322, a gate wire 335 and the like. The gate wire 335 is deposited via a gate insulation film 328 having a thickness of several hundred A on the front surface of the portion of the N-type well area 322 except for the source area 325 and the drain area 326.
The N-MOS 321 includes the source area 325 and the drain area 326, which are formed by introducing N-type or P-type impurities partially into the front layer of the P-type well area 323, the gate wire 335 and the like. The gate wire 335 is deposited via the gate insulation film 328 having a thickness of several hundred A on the front surface of the portion of the P-type well area 323 except for the source area 325 and the drain area 326. The gate wire 335 includes polysilicon having a thickness of 3,000 Å to 5,000 Å deposited by the CVD method. By the P-MOS 320 and the N-MOS 321, a C-MOS logic is configured.
In the P-type well area 323, at the portion different from the N-MOS 321, an N-MOS transistor 330 for driving an electrothermal conversion element (heating resistance element) is formed. The N-MOS transistor 330 includes a source area 332 and a drain area 331, which are formed partially on the front layer of the P-type well area 323 by the process, such as introduction and diffusion of impurities, a gate wire 333 and the like. The gate wire 333 is deposited via the gate insulating film 328 on the front surface of the portion except for the source area 332 and the drain area 331 in the P-type well area 323.
In this example, as the transistor for driving the electrothermal conversion element, the N-MOS transistor 330 is used. However, the driving transistor may be any transistor having the capacity to individually drive a plurality of electrothermal conversion elements and capable of obtaining the fine structure as described above and is not limited to the N-MOS transistor 330. Further, in this example, the electrothermal conversion element and the driving transistor thereof are formed on the same substrate, but it may also be possible to form these on separate substrates.
Between each element, such as 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 separation area 324 having a thickness of 5,000 Å to 10,000 Å is formed by field oxidation. By this oxide film separation area 324, each element is separated. In the oxide film separation area 324, the portion corresponding to the heat acting portion 311 functions as a first heat storage layer 334 on the silicon substrate 304.
On the front surface of each element of the P-MOS 320, the N-MOS 321, and the N-MOS transistor 330, an interlayer insulating film 336 including a PSG film having a thickness of about 7,000 Å, a BPSG film or the like is formed by the CVD method. After flattening the interlayer insulating film 336 by heat processing, an Al electrode 337 that becomes a first wire layer is formed via a contact hole penetrating through the interlayer insulating film 336 and the gate insulating film 328. On the front surfaces of the interlayer insulating film 336 and the Al electrode 337, an interlayer insulating film 338 including a SiO2 film having a thickness of 10,000 Å to 15,000 Å is formed by the plasma CVD method. On the front surface of the interlayer insulating film 338, at the portion corresponding to the heat acting portion 311 and the N-MOS transistor 330, the resistant layer 307 including a TaSiN film having a thickness of about 500 Å is formed by the cosputter method. The resistant layer 307 is electrically connected with the Al electrode 337 in the vicinity of the drain area 331 via a through hole formed in the interlayer insulating film 338. On the front surface of the resistant layer 307, the Al wire 308 as s second wire layer that becomes a wire to each electrothermal conversion element is formed. The protective layer 309 on the front surfaces of the wire 308, the resistant layer 307, and the interlayer insulating film 338 includes a SiN film having a thickness of 3,000 Å formed by the plasma CVD method. The anti-cavitation film 310 deposited on the front surface of the protective layer 309 is at least one or more metals selected from Ta, Fe, Ni, Cr, Ge, Ru, Zr, Ir and the like and includes a thin film having a thickness of about 2,000 Å. As the resistant layer 307, it is possible to apply various materials capable of causing film boiling to take place in a liquid, such as TaN0.8, CrSiN, TaAl, WSiN and the like other than TaSiN described above.
Before a voltage is applied to the heating element 10, substantially the atmospheric pressure is kept within the chamber 301. In a case where a voltage is applied to the heating element 10, film boiling takes place in the liquid in contact with the heating element 10 and the air bubble (in the following, referred to as film boiling bubble 13) having occurred expands by a high pressure that acts from the inside (timing 1). The foaming pressure at this time is regarded as about 8 to 10 MPa and this is close to the value of the saturated vapor pressure of water.
The voltage application time (pulse width) is about 0.5 pec to 10.0 μsec, but even after the voltage is no longer applied, the film boiling bubble 13 expands by the inertia of the pressure obtained at timing 1. However, inside the film boiling bubble 13, the negative pressure having occurred accompanying the expansion gradually becomes large and acts in the direction in which the film boiling bubble 13 contracts. Then, after a while, at timing 2 at which the inertial force and the negative pressure become in equilibrium, the volume of the film boiling bubble 13 reaches the maximum and after that, the film boiling bubble 13 contracts rapidly by the negative pressure.
At the time of the film boiling bubble 13 becoming extinct, the film boiling bubble 13 does not become extinct at the entire surface of the heating element 10 but becomes extinct in a very small area at one or more portions. Because of this, in the heating element 10, in the very small area in which the film boiling bubble 13 becomes extinct, a force larger than that at the time of foaming indicated by timing 1 occurs (timing 3).
The occurrence, expansion, contraction, and extinction of the film boiling bubble 13 as explained above are repeated each time the voltage pulse is applied to the heating element 10 and the new UFB 11 is generated each time.
Next, the way the UFB 11 is generated in each process of the occurrence, expansion, contraction, and extinction of the film boiling bubble 13 is explained in more detail.
The surface temperature of the heating element 10 rises up to about 600 to 800° C. during the application of the pulse after that as well and the liquid on the periphery of the film boiling bubble 13 is also heated rapidly. In
The gas-dissolved liquid 3 included in the un-foamed negative pressure area 15 exceeds the pressure solubility limit and precipitates as an air bubble. The diameter of the precipitated air bubble is about 100 nm and does not become extinct in a short time after that and floats while keeping independence within the liquid W. In the present embodiment, the air bubble that precipitates in this manner by the pressure action at the time of contraction of the film boiling bubble 13 is referred to as a second UFB 11B.
In this case, the gas-dissolved liquid 3 included in the un-foamed negative pressure area 15 is resonated by the impact wave at the time of disappearance of the film boiling bubble 13 and at the timing at which the low-pressure surface 17B passes, the gas-dissolved liquid 3 exceeds the pressure solubility limit and makes a phase transition. That is, at the same time as the extinction of the film boiling bubble 13, many air bubbles precipitate within the un-foamed negative pressure area 15. In the present embodiment, the air bubble such as this, which is generated by the impact wave at the time of disappearance of the film boiling bubble 13, is referred to as a fourth UFB 11D.
The fourth UFB 11D that is generated by the impact wave at the time of disappearance of the film boiling bubble 13 appears suddenly in a very short time (less than or equal to 1 μS) in a very narrow thin film area. The diameter is sufficiently smaller than those of the first to third UFBs and the gas-liquid interface energy is higher than those of the first to third UFBs. Because of this, it is considered that the fourth UFB 11D has a characteristic different from those of the first UFB 11A to the third UFB 11C and produces a different effect.
Further, the fourth UFB 11D occurs uniformly at many portions in the concentric sphere-shaped area in which the impact wave propagates, and therefore, the fourth UFB 11D exists uniformly within the chamber 301 from the time in point of generation. At the timing at which the fourth UFB 11D is generated, the first to third UFBs already exist in a large number, but it is unlikely that the existence of these first to third UFBs largely affects the generation of the fourth UFB 11D. Further, it is also unlikely that the occurrence of the fourth UFB 11D causes the first to third UFBs to become extinct.
As explained above, the FUB 11 occurs in a plurality of stages from the occurrence of the film boiling bubble 13 by the heat generation of the heating element 10 until the disappearance of the film boiling bubble 13. In the example described above, the example until the film boiling bubble 13 disappears is shown, but the example in which the UFB is generated is not limited to this. For example, it is possible to generate the UFB also in a case where the film boiling bubble 13 does not disappear by communicating with the atmosphere before the generated film boiling bubble 13 disappears.
Next, a survival characteristic of the UFB is explained. The higher the temperature of the liquid, the lower the solubility characteristic of the gas component is and the lower the temperature, the higher the solubility characteristic of the gas component is. That is, the higher the temperature of the liquid, the more likely the phase transition of the dissolved gas component is facilitated and the UFB becomes more likely to be generated. The liquid temperature and the gas solubility are in an inversely proportional relationship and by the rise in the liquid temperature, the gas having exceeded the saturated solubility becomes an air bubble and precipitates into the liquid.
Because of this, in a case where the liquid temperature rises rapidly from the normal temperature, the solubility characteristic drops immediately and the UFB begins to be generated. Then, as the temperature rises, the thermal solubility characteristic becomes low and the situation in which the many UFBs are generated is brought about.
On the contrary, in a case where the liquid temperature drops from the normal temperature, the gas solubility characteristic becomes high and the generated UFB becomes more likely to liquefy. However, the temperature such as this is sufficiently lower than the normal temperature. Further, even though the liquid temperature drops, the UFB having occurred once has a high internal pressure and high gas-liquid interface energy, and therefore, the possibility that a pressure high enough to destroy the gas-liquid interface acts is very faint. That is, the UFB having been generated once does not simply become extinct as long as the liquid is preserved at the normal temperature and pressure.
In the present embodiment, it can be said that the first UFB 11A explained in
On the other hand, in the relationship between the liquid pressure and the solubility characteristic, the higher the liquid pressure, the higher the gas solubility characteristic is and the lower the pressure, the lower the solubility characteristic is. That is, the lower the liquid pressure, the more likely the phase transition of the gas-dissolved liquid dissolved in the liquid into gas is facilitated, and therefore, the UFB becomes more likely to be generated. In a case where the liquid pressure drops from the normal pressure, the solubility characteristic becomes low immediately and the UFB begins to be generated. Then, as the pressure drops, the pressure solubility characteristic becomes low and the situation in which the many UFBs are generated is brought about.
On the contrary, in a case where the liquid pressure rises from the normal pressure, the gas solubility characteristic becomes high and the generated UFB becomes more likely to liquefy. However, the pressure such as this is sufficiently higher than the atmospheric pressure and further, even though the liquid pressure rises, the UFB having occurred once has a high internal pressure and high gas-liquid interface energy, and therefore, the possibility that a pressure high enough to destroy the gas-liquid interface acts is very faint. That is, the UFB having been generated once does not simply become extinct as long as the liquid is preserved at the normal temperature and pressure.
In the present embodiment, it can be said that the second UFB 11B explained in
In the above, the first to fourth UFBs whose generation factors are different are explained individually, but the above-described generation factors occur simultaneously at many portions accompanying the event, that is, the film boiling. Because of this, there is a case where at least two or more kinds of UFB among the first to fourth UFBs are generated at the same time or a case where the UFB is generated by the cooperation of these generation factors with one another. However, it is common to all the generation factors that these generation factors are brought about by the film boiling phenomenon. In the following, in the present specification, the method of generating the UFB by utilizing film boiling accompanying the rapid heat generation such as this is referred to as the T-UFB (Thermal-Ultra Fine Bubble) generation method. Further, the UFB generated by the T-UFB generation method is referred to as T-UFB and the liquid containing the T-UFB generated by the T-UFB generation method is referred to as T-UFB-contained liquid.
Almost all the air bubbles generated by the T-UFB generation method have a diameter of 1.0 μm or less and the milli bubble and the micro bubble are unlikely to be generated. That is, according to the T-UFB generation method, only the UFB is generated efficiently. Further, the T-UFB that is generated by the T-UFB generation method has higher gas-liquid interface energy than that of the UFB generated by the conventional method and does not simply become extinct as long as being preserved at the normal temperature and pressure. Furthermore, even in a case where a new T-UFB is generated by new film boiling, it is unlikely that the T-UFB generated previously becomes extinct because of the impact thereof. That is, it can be said that the number of T-UFBs included in the T-UFB-contained liquid and the concentration thereof have the hysteresis characteristic for the number of times of occurrence of film boiling in the T-UFB-contained liquid. In other words, it is possible to adjust the concentration of the T-UFB included in the T-UFB-contained liquid by controlling the number of heating elements arranged in the T-UFB generation unit 300 and the number of times of application of the voltage pulse to the heating element.
The cation exchange resin 412 is a synthetic resin obtained by introducing the functional group (ion exchange group) into the high molecular matrix having a three-dimensional mesh structure and the synthetic resin exhibits a spherical particle having a diameter of about 0.4 to 0.7 mm. The high molecular matrix is generally a copolymer of styrene-divinylbenzene and as the functional group, for example, it is possible to use the methacrylic acid-based functional group or the acrylic acid-based functional group. However, the above-described materials are examples. As long as it is possible to effectively remove desired inorganic ions, the above-described materials can be changed in a variety of ways. The UFB-contained liquid W absorbed by the cation exchange resin 412 and from which inorganic ions are removed are collected by the water collection pipe 414 and sent to the next process via the liquid discharge passage 415.
The impurities that are removed by the filtration filter 422 include organic materials that can be mixed in a tube or each unit and mention is made of, for example, organic compounds including silicon, siloxane, epoxy and the like. As the filter film that can be used as the filtration filter 422, mention is made of a sub micrometer mesh filter capable of removing microorganisms as small as bacteria and a nanometer mesh filter capable of removing microorganisms as small as viruses.
After a certain amount of the UFB-contained liquid W is stored in the accommodation container 421, in a case where the vacuum pump 423 is stopped and the valve 424 is opened, the T-UFB-contained liquid in the accommodation container 421 is sent to the next process via the liquid discharge passage 426. Here, as the method of removing impurities of organic matter, the vacuum filtration method is adopted, but as the filtration method using a filter, it is also possible to adopt, for example, the gravity filtration method or the pressure filtration method.
First, in the state where the valve 433 is closed, a predetermined amount of the UFB-contained liquid W is stored in the precipitation container 431 through the liquid introduction passage 432 and this state is left as it is for a while. During this time, the solid bodies included in the UFB-contained liquid W precipitate onto the bottom of the precipitation container 431 by the gravity. Further, among the bubbles included in the UFB-contained liquid, the bubble whose size is comparatively large, such as the micro bubble, floats up to the liquid surface by the buoyant force and is removed from the UFB-contained liquid. In a case where the valve 433 is opened after a sufficiently long time elapses, the UFB-contained liquid W from which solid bodies and large-size bubbles have been removed is sent to the collection unit 500 via the liquid discharge passage 434.
Here, the effect of returning the generated T-UFB-contained liquid W to the dissolving unit 200 again is explained briefly in accordance with the verification contents obtained by the inventors of the present invention performing specific verification. First, in the T-UFB generation unit 300, the 10,000 heating elements 10 were arranged on the element substrate 12. As the liquid W, industrial pure water was used and the industrial pure water was caused to flow through 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 whose voltage is 24 V and whose pulse width is 1.0 μs was applied to each heating element at a drive frequency of 10 KHz.
In a case where the generated T-UFB-contained liquid W was collected by the collection unit 500 instead of returning it to the dissolving unit 200, that is, the number of times of circulation was set to one, in the T-UFB-contained liquid W collected by the collection unit 500, 3.6 billion UFBs were detected in 1.0 mL. On the other hand, in a case where the operation to return the T-UFB-contained liquid W to the dissolving unit 200 was performed nine times, that is, the number of times of circulation was set to ten, in the T-UFB-contained liquid W collected by the collection unit 500, 36 billion UFBs were detected in 1.0 mL. That is, it was confirmed that the UFB content concentration becomes higher in proportion to the number of times of circulation. The number density of UFBs as described above was obtained by counting the UFBs whose diameter is less than 1.0 μm included in the UFB-contained liquid W having a predetermined volume using the measuring instrument (model number SALD-7500) made by Shimadzu Corporation.
The collection unit 500 collects and preserves the UFB-contained liquid W sent from the post-processing unit 400. The T-UFB-contained liquid collected by the collection unit 500 is a UFB-contained liquid of high purity from which various impurities have been removed.
In the collection unit 500, it may also be possible to perform the filtering processing in several stages and classify the UFB-contained liquid W according to T-UFB size. Further, it is predicted that the T-UFB-contained liquid W obtained by the T-UFB generation method has a temperature higher than the normal temperature, and therefore, it may also be possible to provide a cooling unit in the collection unit 500. It may also be possible to provide the cooling unit such as this in part of the post-processing unit 400.
The above is the outline of the UFB generation apparatus 1 and it is of course possible to change the plurality of units as shown schematically and it is not necessary to prepare all the units. It may also be possible to omit part of the above-described units in accordance with the kind of the liquid W and the gas G that are used or the purpose of use of the T-UFB-contained liquid that is generated, and it may also be possible to further add another unit other than the above-described units.
For example, in a case where the gas that is contained in the UFB is the atmosphere, it is possible to omit the preprocessing unit 100 and the dissolving unit 200. On the contrary, in a case where it is desired to contain a plurality of kinds of gas in the UFB, it may also be possible to further add the dissolving unit 200.
Further, it is also possible to integrate the functions of the several units shown in
Further, it may also be possible to provide the removal unit for removing impurities as shown in
In particular, in a case where the impurity removal unit by an ion exchange resin, which is shown in
<<Liquid and Gas that can be Used for T-UFB-Contained Liquid>>
Here, the liquid W that can be used for generating the T-UFB-contained liquid is explained. As the liquid W that can be used in the present embodiments, mention is made of, for example, pure water, deionized water, distilled water, bioactive water, magnetically activated water, lotion, tap water, seawater, river water, service and waste water, lake water, groundwater, rain water and the like. Further, it is also possible to use a mixed liquid including these liquids and the like. Furthermore, it is also possible to use a mixed solvent of water and a water-soluble organic solvent. The water-soluble organic solvent that is used by being mixed with water is not limited in particular and as specific examples, mention is made of as follows. Alkyl alcohols whose carbon number is 1 to 4, 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. Ketone or ketoalcohols, such as acetone and diacetone alcohol. Cyclic ethers, such as tetrahydrofuran and dioxane. Glycols, such as 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-pentanediol, diethylene glycol, triethylene glycol, and thiodiglycol. Lower alkyl ethers of multivalent alcohols, 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, and triethylene glycol monobutyl ether. Polyalkylene glycols, such as polyethylene glycol and polypropylene glycol. Triols, such as glycerin, 1, 2, 6-hexanetriol, and trimethylolpropane. These water-soluble organic solvents can be used alone or two or more kinds may be used together.
As the gas component that can be introduced in the dissolving unit 200, mention is made of, for example, hydrogen, helium, oxygen, nitrogen, methane, fluorine, neon, carbon dioxide, ozone, argon, chlorine, ethane, propane, air and the like. Further, a mixed gas including some of those described above may be accepted. Furthermore, it is not necessarily required to dissolve a material in the gas state in the dissolving unit 200 and it may also be possible to fuse a liquid or solid consisting of desired components in the liquid W. As dissolving in this case, in addition to natural dissolving, dissolving by applying a pressure may be accepted and dissolving accompanied by hydration by electrolytic dissociation, ionization, and chemical reaction may be accepted.
<<Specific Example in a Case where Ozone Gas is Used>>
Here, as one specific example, a case where ozone gas is used as the gas component is explained. First, as the ozone gas generation method, mention is made of the discharge method, the electrolysis method, and the ultraviolet light method. In the following, these methods are explained in order.
The discharge method includes the silent discharge method and the surface discharge method. In the silent discharge method, an alternating-current high voltage is applied between a pair of electrodes arranged in the form of parallel flat plates or in the form of coaxial cylinder while causing oxygen-contained gas to flow. Due to this, discharge takes place in the oxygen-contained gas and ozone gas is generated. It is necessary for one of or both the front surfaces of the pair of electrodes to be covered with dielectric, such as glass. The discharge takes place in the gas (air or oxygen) accompanying the alternate fluctuation of the charge between positive and negative on the dielectric front surface.
On the other hand, in the surface discharge method, the front surface of the planar electrode is covered with dielectric, such as ceramics, and a linear electrode is arranged on the front surface of the dielectric and an alternating-current high voltage is applied between the planar electrode and the linear electrode. Due to this, discharge takes place on the front surface of the dielectric and ozone gas is generated.
A pair of electrodes sandwiching an electrolyte membrane is arranged in water and a direct-current voltage is applied between both the electrodes. Due to this, water electrolysis occurs and ozone gas is generated simultaneously with oxygen on the oxygen generation side. As the ozone generator that is practically used, there is one in which porous titanium having a platinum catalyst layer is used as the cathode, porous titanium having a lead dioxide catalyst layer is used as the anode, and perfluoro sulfonic acid cation exchange resin is as used as the electrolyte membrane or the like. According to this generator, it is possible to generate high concentration ozone whose weight percent is 20 or higher.
By utilizing the principle in which the ozone layer of the earth is generated, ozone gas is generated by irradiating the air or the like with ultraviolet light. As the ultraviolet light, normally, a mercury light is used.
In a case where ozone gas is used as the gas component, it may also be possible to further add the ozone gas generation unit that adopts the methods (1) to (3) described above to the UFB generation apparatus 1 in
Next, the dissolving method of generated ozone gas is explained. As the method suitable to dissolving ozone gas in the liquid W, in addition to the pressure dissolving method shown in
This is a method in which ozone gas is included in the liquid W as bubbles in a mixed manner and ozone gas is dissolved while causing ozone gas to flow together with the liquid W. For example, there is a bubbling method in which ozone gas is blown into a container in which the liquid W is stored from the bottom of the container, an ejector method in which a narrow section is provided in part of a pipe through which the liquid W is caused to flow and ozone gas is blown into the narrow section, a method in which the liquid W and ozone gas are stirred by a pump, or the like. This is a comparatively compact dissolving method and also used in a water purification plant and the like.
This is a method in which the liquid W is caused to flow through the porous Teflon (registered trademark) membrane and ozone gas is caused to flow outside thereof, and ozone gas is absorbed and dissolved into the liquid W.
(iii) Filled Layer Dissolving Method
This is a method in which the liquid W is caused to flow from the top of a filled layer and ozone gas is caused to flow from the bottom, and thereby, ozone gas and the liquid are caused to flow in opposite directions and ozone gas is dissolved into the liquid W within the filled layer.
In a case where the methods (i) to (iii) described above are adopted, it is sufficient to change the dissolving unit 200 of the UFB generation apparatus 1 from the configuration shown in
In particular, for ozone gas whose purity is high, it is required to purchase it in a gas cylinder and the use thereof is limited unless a special environment is prepared from the standpoint of the strong poisonous characteristic. Because of this, it is difficult to generate the ozone micro bubble and the ozone ultra fine bubble by the conventional generation method of the micro bubble or the ultra fine bubble by introducing air (for example, the venturi method, the swirl flow method, the pressure dissolving method and the like).
On the other hand, as the method of generating ozone-dissolved water, a method is useful from the standpoint of safety and easiness, in which ozone is generated from oxygen supplied by the discharge method, the electrolysis method, or the ultraviolet light method and the ozone is dissolved into water or the like at the same time of the generation thereof.
However, in a case where the cavitation method or the like is adopted, it is possible to generate the ozone ultra fine bubble by using ozone-dissolved water, but the size of the apparatus becomes large and such a problem remains that it is not possible to increase the density of the ozone ultra fine bubble.
In contrast to this, the T-UFB generation method of the present embodiment is more excellent that other generation methods, such as the cavitation method, in that it is possible to relatively reduce the size of the apparatus and generate high concentration ozone ultra fine bubbles from ozone-dissolved water.
Next, the features and effects of the T-UFB generation method explained as above are explained in comparison to the conventional UFB generation method. For example, in the conventional air bubble generation apparatus represented by the venturi method, air bubbles of various sizes are generated in the downstream area of a decompression structure by providing the mechanical decompression structure, such as a decompression nozzle, in part of the flow passage and a liquid is caused to flow under a predetermined pressure so that the liquid passes the decompression structure.
In this case, among the generated air bubbles, the buoyant force acts on the bubbles whose size is comparatively large, such as the milli bubble and the micro bubble, and therefore, after a while, they float up to the liquid surface and become extinct. Further, the UFB on which the buoyant force does not act does not have so large gas-liquid interface energy, and therefore, it becomes extinct together with the milli bubble and the micro bubble. In addition, even by arranging the above-described decompression structure in series and causing the same liquid to flow through the decompression structure repeatedly, it is not possible to preserve the UFBs whose number corresponds to the number of times of repetition for a long time. That is, it is difficult to keep the UFB contain concentration at a predetermined value for a long time in the UFB-contained liquid generated by the conventional UFB generation method.
In contrast to this, in the T-UFB generation method of the present embodiment, which utilizes film boiling, the rapid change in temperature from the normal temperature to about 300° C. and the rapid change in pressure from the normal pressure to about several MPa are caused to take place locally in the very close vicinity of the heating element. This heating element has the shape of a rectangle whose one side is about several tens of μm to hundred μm. Compared to the conventional UFB generator, the size is about 1/10 to 1/100. Further, by the gas-contained liquid existing in the very thin film area on the front surface of the film boiling bubble instantaneously (for a very short time less than or equal to a microsecond) exceeding the thermal solubility limit or the pressure solubility limit, the phase transition takes place and the UFB precipitates. In this case, the bubbles whose size is comparatively large, such as the milli bubble and the micro bubble, is hardly generated and in the liquid, the UFB whose diameter is about 100 nm is contained with very high purity. Further, the T-UFB thus generated has sufficiently high gas-liquid interface energy, and therefore, the T-UFB is unlikely to be damaged in the normal environment and can be preserved for a long time.
In particular, in the present embodiment in which the film boiling phenomenon capable of forming the gas interface locally in the liquid, it is possible to form the interface in part of the liquid and make the area that acts in terms of heat and pressure accompanying the formation an extremely local range without affecting the entire liquid area. As a result of that, it is possible to generate the desired UFB stably. Further, by circulating the liquid and further giving the UFB generation condition to the generated liquid, it is possible to additionally generate the new UFB with less influence on the already existing UFB. As a result of that, it is possible to manufacture the UFB liquid with the desired size and concentration comparatively easily.
Further, in the T-UFB generation method, because of having the above-described hysteresis characteristic, it is possible to increase the content concentration up to the desired concentration while maintaining high purity. That is, according to the T-UFB generation method, it is possible to efficiently generate the UFB-contained liquid whose purity and concentration are high and which can be preserved for a long time.
Here, the method of dissolving ozone gas into the liquid W is explained, but the method may be a method of dissolving nitrogen monoxide in place of ozone gas. The case where nitrogen monoxide is used is suitable to the medical clinical application by utilizing the biological activity function.
Further, to the T-UFB manufacturing container 1200, a collection unit 1206 configured to collect the UFB-contained liquid generated within the T-UFB manufacturing container 1200 is also attached. The collection unit 1206 collects the ultra fine bubble-contained liquid generated within the T-UFB manufacturing container 1200 through a collection passage and a collection port (also referred to as discharge port), which the T-UFB manufacturing container 1200 comprises. Then, in order to maintain airtightness of the T-UFB manufacturing container 1200 and high pressure within the container, a hermetic lid 1201 and a sealing material 1202 are arranged. It is possible to control the internal pressure within the T-UFB manufacturing container 1200 to the atmospheric pressure or higher by adjusting the gas introduction pressure from the gas supply unit 1204 in order to increase the internal pressure. Further, in order to increase the gas solubility concentration in the liquid, a cooling unit 1203 that comes into contact with the outer circumferential side surface of the T-UFB manufacturing container 1200 is arranged. By this cooling unit, the liquid temperature within the T-UFB manufacturing container 1200 is adjusted to the temperature lower than or equal to the temperature in the room in which the container is installed (that is, lower than or equal to the environment temperature), desirably, 10° C. or lower.
Next, within the T-UFB manufacturing container 1200 shown in
Within the T-UFB manufacturing container 1400 shown in
Further, within the T-UFB manufacturing container 1400, a filter 1420 in which minute holes are bored is arranged in order to concentrate the generated T-UFBs 1415. This filter has a number of minute holes whose diameter is less than or equal to 1.0 μm and allows only the UFBs whose diameter is less than or equal to 1.0 μm among the plurality of the UFBs having occurred in the T-UFB generation unit 1410 to pass.
Next, by using
Then, by a cooling unit 1503 arranged outside the T-UFB manufacturing container 1500, the gas-dissolved water 1507 at the top is cooled and due to the effect of Marangoni convection, the cooled gas-dissolved water is supplied to the vicinity of the T-UFB generation unit 1510. Due to this, it is possible to suppress the rise in temperature of the substrate of the T-UFB generation unit 1510. Further, by the gas-dissolved water 1507 being cooled, it is possible to increase the solubility of gas supplied from a gas supply unit 1504 and as a result, it is possible to further dissolve the gas into the T-UFB-dissolved water. That is, as regards the solubility of gas in a liquid, the gas saturated solubility is determined depending on temperature and pressure, but the gas having contributed to the UFB generation by the T-UFB generation unit 1510 changes into gas that does not depend on the magnitude of solubility by being included within the UFB. As described above, according to the present embodiment, it is possible to implement a mechanism that reduces the solubility of gas in a liquid and further dissolves the gas into the liquid whose gas solubility has been reduced.
In a case where nitrogen monoxide is dissolved in a liquid, it is preferable to use a CFC-based material having nitrogen monoxide resistance for the pipe and the like through which nitrogen monoxide passes before being dissolved.
It is desirable for the height of the barrier to be not less than 1.0 μm and not more than 100 μm. In view of the initial thickness in film boiling described previously, in a case where the height is not more than or equal to 1.0 μm, the effect of suppression of interference between the adjacent heaters is not obtained. On the other hand, in view of the maximum bubble diameter, in a case where the height is more than or equal to 100 μm, there is a possibility that the liquid supply capacity after bubble disappearance is suppressed. The height of the barrier is preferably 10 to 50 μm.
Further, as the material of the barrier, a film deposition material, such as silicon nitride, a photosensitive epoxy resin or the like is suitable. However, in view of ozone resistance and base resistance, inorganic silicon nitride is preferable.
Although not shown in
According to one embodiment of the present invention, it is made possible to provide a manufacturing apparatus of an ultra fine bubble-contained liquid that can be utilized effectively because high concentration ultra fine bubbles are maintained for a long time at the time of manufacturing of the ultra fine bubble-contained liquid.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2021-040221, filed Mar. 12, 2021, which is hereby incorporated by reference wherein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-040221 | Mar 2021 | JP | national |
