JP2023002197A - Ultra fine bubble concentrated liquid production method - Google Patents

Abstract

To provide ultra fine bubble liquid with a high number density of ultra fine bubbles.SOLUTION: A method for producing ultra fine bubble concentrated liquid comprises: (a) a first liquid preparation process for preparing a first liquid containing a first fluid in a liquid state and a second fluid in a gaseous state, in which bubbles of the second fluid having a diameter of less than 1 μm are mixed in the first fluid at a first number density; (b) a concentration process for selectively solidifying the first fluid by cooling the first liquid while agitating it; and (c) a separation process for separating the first fluid solidified by the concentration process (b) from a concentrated liquid in which bubbles of the second fluid are mixed in the unsolidified first fluid at a second number density higher than the first number density.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a technology for producing an ultra-fine bubble concentrate.

There is a technique for concentrating the number density of ultra-fine bubbles contained in ultra-fine bubble water by heating the ultra-fine bubble water under reduced pressure conditions to vaporize the liquid component of the ultra-fine bubble water (for example, Non-Patent Document 1 reference). In addition, Non-Patent Document 2 describes the results of evaluating the stability of ultra-fine bubbles in high-temperature and low-temperature environments.

Shunya Tanaka, 3 others, “Concentration and Dilution of Ultrafine Bubbles in Water”, Colloids and Interfaces, (Switzerland), Multidisciplinary Digital Publishing Institute (MDPI), 5 November 2020 Takaki Kobayashi (Niigata University), 6 others, ``Study of stability of ultra-fine bubbles in high and low temperature environments'', Proceedings of Multiphase Flow Symposium 2020, Japan Society for Multiphase Flow, (Japan), Japan Society for Multiphase Flow, August 21, 2020

An ultra-fine bubble liquid is a liquid in which a large number of fine bubbles are present, and the diameter of each of the large number of bubbles is less than 1 μm. In general, it is known as ultra-fine bubble water, in which a large number of fine air bubbles are present in water, and because it has different characteristics from water and carbonated water, it is being considered for use in various industrial fields. there is Further, in consideration of stabilizing the performance of the ultra-fine bubble liquid or facilitating the handling of the ultra-fine bubble liquid, a technique for controlling the number density of the ultra-fine bubbles, in other words, the number concentration of the ultra-fine bubbles is desired.

As a method for producing an ultra-fine bubble liquid, various methods are known, for example, a method in which a gas-liquid mixed fluid is swirled to shear the gas-liquid mixed fluid. However, there is a limit to the number density of ultra-fine bubbles in an ultra-fine bubble liquid obtained by a general method for producing ultra-fine bubble water. The inventor of the present application is studying a technique for producing an ultra-fine bubble liquid having a high number density of ultra-fine bubbles.

In the case of the method of vaporizing the liquid component of the ultra-fine bubbled water and concentrating the number density of the ultra-fine bubbles contained in the ultra-fine bubbled water, as in the above-mentioned Patent Document 1, high-concentration ultra-fine bubbled water is obtained. can.

However, in the case of the above method, since a heating process is included in the concentration step, the properties of the resulting ultra-fine bubble liquid are limited. For example, when the liquid to be processed to be subjected to the concentration step contains volatile components such as flavors, the volatile components are vaporized by applying the heating process.

An object of the present invention is to provide a technique for producing an ultra-fine bubble liquid having a high number density of ultra-fine bubbles.

A method for producing an ultra-fine bubble concentrate, which is one embodiment, includes the following steps.
(A) a first fluid comprising a first fluid in a liquid state and a second fluid in a gaseous state, wherein bubbles of the second fluid having a diameter of less than 1 μm are mixed in the first fluid at a first concentration; The process of preparing a liquid.
(B) a step of selectively solidifying the first fluid by cooling the first liquid while stirring;
(C) the first fluid solidified in the step (B) and the first fluid that has not solidified are mixed with the bubbles of the second fluid at a second concentration higher than the first volume concentration; separating the concentrated liquid and the

According to a representative embodiment of the present invention, an ultra-fine bubble liquid having a high number density of ultra-fine bubbles can be obtained.

FIG. 4 is an explanatory diagram schematically showing the behavior of non-ultrafine bubbles and ultrafine bubbles present in water. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram showing an example of a flow of a method for producing a concentrate of ultra-fine bubbles according to an embodiment; FIG. 4 is a cross-sectional view showing an ultra-fine bubble liquid before concentration treatment; 4 is a cross-sectional view schematically showing a state in which the ultra-fine bubble liquid before the concentration treatment shown in FIG. 3 is supplied into the container of the concentrator used in the concentration step shown in FIG. 2. FIG. 5 is a cross-sectional view schematically showing a state in which part of the fluid is formed as a solidified film in the container by operating the stirring mechanism and the cooling mechanism of the concentrator shown in FIG. 4 at the same time. . 6 is an enlarged sectional view schematically showing a state in which the solidified film and the concentrated liquid shown in FIG. 5 are separated; FIG. FIG. 4 is a cross-sectional view showing a first liquid that is a modification to FIG. 3; FIG. 8 is a cross-sectional view schematically showing a state in which the ultra-fine bubble liquid before the concentration treatment shown in FIG. 7 is supplied into the container of the concentrating device, which is a modified example of the concentrating device shown in FIG. 4 . FIG. 9 is a cross-sectional view schematically showing a state in which part of the fluid is formed as a solidified film in the storage section by simultaneously operating the stirring mechanism section and the cooling mechanism section of the concentrator shown in FIG. 8 ; FIG. 3 is an explanatory diagram showing a modified example of the flow shown in FIG. 2; FIG. 11 is a cross-sectional view showing a state after the step of adding the first liquid shown in FIG. 10; FIG. 11 is a cross-sectional view showing a state after the second concentration step shown in FIG. 10;

<About ultra fine bubbles>
FIG. 1 is an explanatory diagram schematically showing the behavior of non-ultrafine bubbles and ultrafine bubbles present in water. In the example shown in FIG. 1, the liquid 10 is water. Each of the ultra-fine bubbles 20A and the non-ultra-fine bubbles 20B is air bubbles. Various substances can be used for the liquid and bubbles of the ultra-fine bubble liquid produced by the technique described below, but in the following embodiments, the liquid 10 is water and the ultra-fine bubbles 20A are air. A case will be taken up and explained as an example.

In the example shown in FIG. 1, there are a plurality of bubbles 20 in liquid 10 including ultra-fine bubbles 20A and non-ultra-fine bubbles 20B. The ultra-fine bubbles 20A and the non-ultra-fine bubbles 20B can be distinguished by the diameter of the air bubbles 20. FIG. The bubble diameter D1 of the ultra-fine bubbles 20A is less than 1 μm. The bubble diameter D2 of the non-ultra-fine bubbles 20B is 1 μm or more. Since the ultra-fine bubbles 20A have a small bubble diameter, they have a shape that can be regarded as almost spherical. On the other hand, the non-ultra-fine bubbles 20B include those existing in the liquid 10 in various shapes such as elliptical spheres as illustrated in FIG. In FIG. 1, the short diameter of the elliptical sphere is shown as the bubble diameter D2 for convenience, but the bubble diameter D2 of the non-ultra-fine bubbles 20B is defined as the diameter when the non-ultra-fine bubbles 20B are converted into a sphere. The bubble diameter D1 of the ultra-fine bubbles 20A is defined as the diameter when each bubble 20 is converted into a sphere, like the bubble diameter D2 described above.

As schematically shown by arrows in FIG. 1, the non-ultra-fine bubbles 20B float toward the liquid surface 10t due to buoyancy generated in the liquid 10 and burst at the liquid surface 10t.

On the other hand, since the ultra-fine bubbles 20A have a small bubble diameter D1 of 1 μm or less, they can stably maintain their shape in the liquid 10 . In addition, since the bubble diameter D1 of the ultra-fine bubbles 20A is small, the floating speed of the ultra-fine bubbles 20A calculated by the Stokes equation is faster than the random movement speed of the ultra-fine bubbles 20A in the up, down, left, right, front and back due to the Brownian motion. slow. As a result, the ultra-fine bubbles 20A do not float toward the liquid surface 10t and can continue to float in the liquid 10 for a long period of time.

Among the non-ultra-fine bubbles 20B, those with a relatively small bubble diameter D2 (for example, 100 μm or less) are called microbubbles, and are sometimes collectively called fine bubbles as the ultra-fine bubbles 20A. It can be visually identified as follows. That is, water containing microbubbles is cloudy. On the other hand, water containing only the ultra-fine bubbles 20A is colorless and transparent. This is because most of the ultra-fine bubbles 20A do not scatter visible light due to the small bubble diameter D1 of the ultra-fine bubbles 20A.

<Number density of ultra-fine bubbles>
The inventor of the present application is studying a technique for controlling the number density of ultra-fine bubbles. The “ultra-fine bubble number density” is the number of ultra-fine bubbles contained in a unit volume of ultra-fine bubble liquid. "Ultra-fine bubble number density" can also be read as "ultra-fine bubble number concentration".

The number density of ultra-fine bubbles in the ultra-fine bubble liquid can be measured, for example, as follows. In the nanoparticle tracking method, which is a representative measurement method, the ultrafine bubble liquid is irradiated with a two-dimensional plane laser beam, and the number of ultrafine bubbles in the volume of the field of view is determined from the photographing of the laser scattered light spots from the ultrafine bubbles moving in Brownian motion. The number density can be obtained by counting .

Methods for producing an ultra-fine bubble liquid include the following methods. For example, in the pressurized dissolution manufacturing method, the second fluid is pressurized and dissolved in the liquid first fluid, and then the pressure is rapidly reduced to vaporize the second fluid by utilizing the supersaturated state. This is a foaming method. The gas-liquid mixed fluid shearing production method is a method of pulverizing a gas-liquid mixed fluid in which gas and liquid are mixed to generate fine bubbles. Methods for pulverizing the gas-liquid mixed fluid include, for example, a method of swirling the gas-liquid mixed fluid and utilizing its swirling force, and a method of passing the gas-liquid mixed fluid through a static mixer and utilizing its shearing force. and can be exemplified. Further, the aeration type manufacturing method is a method of supplying gas into a liquid through a porous film having fine pores formed therein.

In the case of the above method, an ultra-fine bubble liquid can be produced, but it is difficult to control the number density of ultra-fine bubbles in the liquid. Therefore, the inventors of the present application have investigated a method of controlling the number density of ultra-fine bubbles by diluting or concentrating the ultra-fine bubble liquid obtained by the above-described methods. As described in Non-Patent Document 1, it has been found that the number density of ultra-fine bubbles can be reduced to a predetermined value by diluting the ultra-fine bubble water. As a method for increasing the number density of ultra-fine bubbles to a predetermined value, as described in Non-Patent Document 1 above, an evaporator is used to heat ultra-fine bubble water under reduced pressure conditions to remove moisture. There is a method of concentrating ultra-fine bubble water by vaporizing it. However, a concentration method that does not require a heating process has not been found.

As an application of the ultra-fine bubble liquid, the added value may be improved by adding an additive to the ultra-fine bubble liquid. There are various modifications of additives, but in the case of highly volatile additives such as flavors, the additives may volatilize during the heating process during concentration. Therefore, the inventors of the present application have investigated a method capable of concentrating an ultra-fine bubble liquid containing, for example, a highly volatile material as an additive.

<Method for Producing Ultra-Fine Bubble Concentrate>
The method for producing a concentrate of ultra-fine bubbles according to the present embodiment, which will be described below, comprises a first liquid preparation step, a concentration step, and a separation step, as shown in FIG. FIG. 2 is an explanatory diagram showing an example of the flow of the method for producing a concentrate of ultra-fine bubbles according to the present embodiment. FIG. 3 is a cross-sectional view showing the ultra-fine bubble liquid before concentration treatment.

In the first liquid preparation step shown in FIG. 2, the first liquid UFB1 shown in FIG. 3 is prepared. The first liquid UFB 1 includes a liquid state fluid (first fluid) 11 and a gaseous state fluid (second fluid) 21 . The first liquid UFB1 is a so-called ultra-fine bubble liquid, and the diameter of the bubbles 21A of the fluid 21 (bubble diameter D1 shown in FIG. 1) is less than 1 μm. Liquid 30 containing fluid 11 is mixed with bubbles 21A at a first number density. Since the first liquid UFB1 is an ultra-fine bubble liquid before concentration treatment, the value of the first number density is arbitrary. For example, the first number density (number of bubbles 21A contained in 1 ml of first liquid UFB1) is, for example, about 0.1×10 ⁸ to 30×10 ⁸ /mL.

As an example, the liquid 30 made up of the fluid 11 is water, and the bubbles 21A made up of the fluid 21 are air. However, the materials used for fluid 11 and fluid 21 have various applications. For example, as will be described later as a modified example, a liquid obtained by dissolving a volatile substance such as a flavor in the fluid 11 that is water can be used instead of the liquid 30 . As for the fluid 21, in addition to air, a fluid containing an inert gas such as nitrogen or a rare gas, or a reactive gas such as ozone can be used.

A known method can be adopted as a method for manufacturing the first liquid UFB1. For example, the pressure dissolution type production method, the gas-liquid mixed fluid shearing type production method, the gas-liquid mixed fluid pulverization method, or the air diffusion type production method described above can be used. A first liquid UFB1, which is an ultra-fine bubble liquid in which ultra-fine bubbles are dispersed at a first number density, is obtained by any of the methods described above.

Next, in the concentration step shown in FIG. 2, the fluid 11 is selectively solidified by cooling the first liquid UFB1 while stirring. That is, the method for producing an ultra-fine bubble concentrated liquid according to the present embodiment concentrates the ultra-fine bubble liquid by using a cooling process. 4 is a cross-sectional view schematically showing a state in which the ultra-fine bubble liquid before the concentration treatment shown in FIG. 3 is supplied into the container of the concentrating device used in the concentrating step shown in FIG. 2; is. 5 is a cross-sectional view schematically showing a state in which part of the fluid is formed as a solidified film in the container by operating the stirring mechanism and the cooling mechanism of the concentrator shown in FIG. 4 at the same time. .

The concentration step shown in FIG. 2 is performed by, for example, the concentration apparatus 100 shown in FIG. The ultra-fine bubble liquid concentrator 100 includes a container 40 for containing the first liquid UFB1, a stirring mechanism 50 capable of stirring the first liquid UFB1 in the container 40, and a and a cooling mechanism section 60 capable of cooling the first liquid UFB1.

In the example shown in FIG. 4, the stirring mechanism unit 50 of the concentrating device 100 includes a rotating shaft 51 that rotates within the housing unit 40, stirring blades 52 attached to the rotating shaft 51, a motor 53 that drives the rotating shaft 51, It has The cooling mechanism section 60 of the concentrating device 100 includes a refrigerant 61 arranged around the housing section 40 and a bathtub 62 containing the refrigerant 61 . Further, in the example shown in FIG. 4 , the bathtub 62 is provided with a supply port 62A for the coolant 61 and a discharge port 62B for the coolant 61 . The refrigerant 61 supplied from the supply port 62A convects within the bathtub 62 and is discharged from the discharge port 62B.

The refrigerant 61 filled in the bath 62 is, for example, a liquid that does not freeze at 0°C or lower (a liquid called antifreeze), and is cooled to a temperature below 0°C. Although the temperature differs depending on the type of the coolant 61, for example, the temperature of the coolant 61 can be set to about -20.degree. C. to -25.degree. At least a portion of the containing portion 40 is immersed in the coolant 61 in the bath 62 . As a result, the first liquid UFB1 in the containing portion 40 is cooled through the containing portion 40. As shown in FIG. Further, by driving the motor 53, the rotation shaft 51 of the stirring mechanism section 50 is rotated. The rotating shaft 51 rotates in the direction indicated by the arrow around a rotating shaft VL1, which is a virtual line indicated by a two-dot chain line in FIG. The stirring blades 52 attached to the rotating shaft 51 rotate as the rotating shaft 51 moves. Since the stirring blades 52 are immersed in the first liquid UFB1 inside the container 40, the first liquid UFB1 is stirred due to the rotation of the stirring blades 52. As shown in FIG.

In the case of the concentrating device 100 shown in FIG. 4, the first liquid UFB1 is cooled while being stirred by simultaneously operating the stirring mechanism section 50 and the cooling mechanism section 60 . Although the number of rotations of the rotating shaft is not particularly limited, for example, a method of rotating at a rotation speed of about 300 to 600 rpm (300 to 600 rotations per minute) can be exemplified.

A portion of the housing portion 40 immersed in the coolant 61 is cooled. In the example shown in FIG. 5, of the inner surface 41 of the accommodating portion 40, the entire bottom surface 41b and a portion of the side surface 41s (the portion connected to the bottom surface 41b) are cooled. If the temperature of this cooled portion is below the freezing point of fluid 11, as shown in FIG. The fluid 11 gradually begins to solidify from the portion that touches the bottom surface 41b (and the cooled portion of the side surface 41s) of the containing portion 40, and the solidified fluid 11 forms a solidified film 31 on the inner surface 41 of the containing portion 40. be. If the fluid 11 is water, the solidified film 31 is ice.

At this time, since the temperature of the coolant 61 is set to a temperature higher than the condensation point of the fluid 21, the fluid 21 does not liquefy and remains in the remaining liquid 30 in a gaseous state. In addition, in the concentration step of the present embodiment, while the first liquid UFB1 (see FIG. 4) containing the fluid 11 and the fluid 21 is continuously stirred, part of the liquid 30 is gradually solidified. Therefore, the air bubbles 21A are less likely to be confined in the solidified film 31 compared to the case where the first liquid UFB1 is instantaneously solidified. Further, when the solidified film 31 made of the substance of the fluid 11 is formed, the wettability of the fluid 11 to the solidified film 31 is higher than that of the fluid 21 . Due to this difference in wettability with respect to the solidified film 31 , the air bubbles 21A are less likely to adhere to the solidified film 31 , and as a result, the solidified film 31 tends to grow as a film of the fluid 11 . Therefore, according to the concentration step of the present embodiment, the fluid 11 can be selectively solidified.

Thus, according to this embodiment, the fluid 11 can be selectively solidified. As a result, the number density (second number density) of bubbles 21A contained in the remaining liquid 30 shown in FIG. density). That is, by the concentration step of the present embodiment, a concentrated liquid UFB2 in which the number density of the bubbles 21A, which are ultra-fine bubbles, is concentrated is obtained. The number density of the concentrated liquid UFB2 increases in proportion to the operation time of the concentrator 100. For example, when the concentrator 100 is operated for 120 minutes, the second number density is about twice the first number density. was confirmed experimentally.

Next, in the separation step shown in FIG. 2, as shown in FIG. 6, the concentrated liquid UFB2 and the solidified film 31 are separated. FIG. 6 is an enlarged cross-sectional view schematically showing a state in which the solidified film and the concentrated liquid shown in FIG. 5 are separated. In the concentrated liquid UFB2, bubbles 21A of the fluid 21 are mixed in the liquid 30 containing the fluid 11 that did not solidify in the concentration process at a second number density higher than the first number density. That is, the concentrated liquid UFB2 is an ultra-fine bubble concentrated liquid in which the number density of ultra-fine bubbles is concentrated compared to the first liquid UFB1 shown in FIG.

The example shown in FIG. 6 shows an example in which only the concentrated liquid UFB2 is selectively transferred into the container 42 by inverting the container 40 taken out from the concentrator 100 shown in FIG. However, the separation method is not limited to the method shown in FIG. For example, a method of transferring the concentrated liquid UFB2 to the container 42 shown in FIG. 6 using a liquid transfer mechanism such as a pump (not shown) while the container 40 is fixed in the concentrating device 100 shown in FIG. 5 can be exemplified. In the case of the present embodiment, since the solidified film 31 is solid, it is relatively easy to separate the concentrator 100 and the solidified film 31 .

Concentrated liquid UFB2, which is an ultra-fine bubble concentrated liquid, is obtained by the above steps. Since the solidified film 31 remaining in the storage section 40 can be easily liquefied by heating, for example, it is preferably removed from the storage section 40 after the liquefaction process.

In this embodiment, as shown in FIG. 5, it is necessary to selectively solidify the fluid 11 while stirring the liquid 30. Also, the solidified film 31 may interfere with the rotating operation of the rotating shaft 51 . Therefore, it is preferable to complete the concentration process before the thickness of the solidified film 31 becomes thick enough to contact the stirring blade 52 and the rotating shaft 51, and remove the solidified film 31 after the separation process.

When an ultra-fine bubble concentrated liquid with a higher concentration rate than the concentrated liquid UFB2 is required, the concentrated liquid UFB2 shown in FIG. 6 is regarded as the first liquid UFB1 shown in FIG. 3, and the concentration step shown in FIG. and separation steps are preferably repeated. To control the number density of ultra-fine bubbles in the obtained ultra-fine bubble concentrate by controlling the volume of the solidified film 31 formed in the concentration step and the number of repetitions of the concentration step and the separation step shown in FIG. can be done.

<Modification containing volatile substance>
Next, a particularly effective usage example by applying the method for producing an ultra-fine bubble concentrate according to the present embodiment will be described. FIG. 7 is a cross-sectional view showing a first liquid that is a modification to FIG.

The first liquid UFB3 shown in FIG. 7 is different from the first liquid UFB1 shown in FIG. . The volatile substance 12 is a substance that is more volatile than the fluid 11, such as flavor. As described above, the method for producing an ultra-fine bubble concentrated liquid according to the present embodiment can concentrate an ultra-fine bubble liquid without using a heating process. It is particularly effective when used for the concentration of

In addition, in the case of the method of adding the volatile substance 12 as an additive substance to the ultra-fine bubble concentrated liquid concentrated to a predetermined number density, a heating process can also be included in the concentration process. However, the higher the number density of the ultra-fine bubbles, the higher the possibility that the ultra-fine bubbles existing in the liquid will aggregate. For this reason, during the operation of adding the additive substance and dissolving it into the ultra-fine bubble concentrated liquid, there is a high possibility that the ultra-fine bubbles existing in the liquid will agglomerate. Therefore, from the viewpoint of ease of work, even if the volatile substance 12 is added as an additive substance, the method of the present embodiment that can add the volatile substance at the stage of the first liquid UFB3 before concentration is Advantageous. Moreover, in the case of the method of the present embodiment, volatilization of flavor can be suppressed even when the raw material contains a flavor component, for example, when the liquid 30 contains fruit juice.

Even when the first liquid UFB3 shown in FIG. 7 is used, the number density of ultra-fine bubbles in the first liquid UFB1 containing the volatile substance 12 is concentrated by the same method as described using FIGS. be able to.

In the concentration step, the solidified film 31 is formed in a state in which the volatile substance 12 (see FIG. 7) is dissolved in the fluid 11 shown in FIG. Therefore, the components of the volatile substance 12 are less likely to be included in the solidified film 31 . As a result, the volatile substance 12 is less likely to be taken into the solidified film 31, so the remaining concentrated liquid UFB2 is in a state in which the bubbles 21A, which are ultra-fine bubbles, and the volatile substance 12 are concentrated.

<Modified example of concentrator>
Next, modifications to the concentrator 100 shown in FIGS. 4 and 5 will be described. 8 is a cross-sectional view schematically showing a state in which the ultra-fine bubble liquid before the concentration process shown in FIG. 7 is supplied into the container of the concentrating device, which is a modification of the concentrating device shown in FIG. It is a diagram. 9 is a cross-sectional view schematically showing a state in which part of the fluid is formed as a solidified film in the container by simultaneously operating the stirring mechanism and the cooling mechanism of the concentrator shown in FIG. . The process flow of the method for producing the ultra-fine bubble concentrate using the concentrator 101 (see FIG. 8) described in this section is the same as that shown in FIG. Therefore, the following description will be made with reference to FIG. 2 as necessary.

Since the first liquid preparation step shown in FIG. 2 has already been described, redundant description will be omitted. The first liquid prepared in the first liquid preparation step in this modification may be the first liquid UFB1 shown in FIG. You can stay. In the following description, an example using the first liquid UFB3 shown in FIG. 7 will be described as a representative example.

In the concentration step shown in FIG. 2, the fluid 11 is selectively solidified by cooling the first liquid UFB3 while stirring. The concentration step of this modified example is performed, for example, by a concentration device 101 shown in FIG. The ultra-fine bubble liquid concentrating device 101 includes a storage section 40 for storing the first liquid UFB1, a stirring mechanism section 50 capable of stirring the first liquid UFB1 in the storage section 40, and and a cooling mechanism section 60 capable of cooling the first liquid UFB1. This point is similar to the concentrator 100 shown in FIG.

A concentrating device 101 as a modified example shown in FIG. 8 differs from the concentrating device 100 shown in FIG. 4 in the following points. The bottom surface 46b of the storage unit 45 provided in the concentrator 101 has a round bottom and does not have a boundary with the side surface. In the concentration step, a solidified film 31 (see FIG. 9) made of the fluid 11 is formed on the inner surface 46 of the container 45 including the bottom surface 46b. In other words, the inner surface 46 of the housing portion 45 on which the solidified film 31 is formed in the concentration step is a curved surface. In addition, the stirring mechanism 50 of the concentrating device 101 has a motor (driving motor) connected to the storage section 45 in a state in which the storage section 45 can be driven to rotate around the rotation axis (first rotation axis) VL2. part) 53 . In the concentration step, the first liquid UFB3 in the storage section 45 is agitated by rotating the storage section 45 itself while part of the storage section 45 (bottom surface 46 b ) is cooled by the cooling mechanism section 60 .

The cooling mechanism section 60 of the concentrating device 101 includes a refrigerant 61 arranged around the housing section 40 and a bathtub 62 containing the refrigerant 61 . In the example shown in FIG. 8 , the bathtub 62 is provided with a supply port 62A for the coolant 61 and a discharge port 62B for the coolant 61 . The refrigerant 61 supplied from the supply port 62A convects within the bathtub 62 and is discharged from the discharge port 62B. The cooling mechanism section 60 is the same as the concentrator 100 shown in FIG.

The refrigerant 61 filled in the bath 62 is, for example, a liquid that does not freeze at 0°C or lower (a liquid called antifreeze), and is cooled to a temperature below 0°C. For example, the temperature of the coolant 61 can be set to about -20°C to -25°C. At least a portion of the containing portion 45 is immersed in the coolant 61 in the bath 62 . As a result, the first liquid UFB3 in the containing portion 45 is cooled through the containing portion 45. As shown in FIG. Further, by driving the motor 53, the accommodating portion 45 itself rotates around the rotation axis VL2. The first liquid UFB3 contained in the containing portion 45 moves and is stirred within the containing portion 45 as the containing portion 45 rotates.

In the case of the concentrating device 101 shown in FIG. 8, the first liquid UFB3 is cooled while being stirred by simultaneously operating the stirring mechanism section 50 and the cooling mechanism section 60 . Although the number of rotations of the rotation operation of the housing part 45 is not particularly limited, for example, a method of rotating at a rotation speed of about 300 to 600 rpm can be exemplified as in the example described with reference to FIG.

The first liquid UFB1 is cooled by the cold heat of the coolant 61 through the storage portion 45. As shown in FIG. Therefore, the point that the solidified film 31 formed by selectively solidifying the fluid 11 is formed on the inner surface 46 of the housing portion 45 is the same as the example described with reference to FIG. 5 . Since the temperature of the coolant 61 is set to a temperature higher than the condensation point of the fluid 21, the fluid 21 does not liquefy and remains in the remaining liquid 30 in a gaseous state. Also in this modification, while the first liquid UFB3 (see FIG. 8) containing the fluid 11, the volatile substance 12, and the fluid 21 is continuously stirred, part of the liquid 30 is gradually solidified. Therefore, the air bubbles 21A are less likely to be confined in the solidified film 31 compared to the case where the first liquid UFB3 is instantaneously solidified. Further, when the solidified film 31 made of the substance of the fluid 11 is formed, the wettability of the fluid 11 to the solidified film 31 is higher than that of the fluid 21 . Due to this difference in wettability with respect to the solidified film 31 , the air bubbles 21A are less likely to adhere to the solidified film 31 , and as a result, the solidified film 31 tends to grow as a film of the fluid 11 . Therefore, according to the concentration step of the present embodiment, the fluid 11 can be selectively solidified.

Similar to the examples described with reference to FIGS. 4 and 5, the fluid 11 can be selectively solidified also in this modification. As a result, the number density (second number density) of bubbles 21A contained in the remaining liquid 30 shown in FIG. density). That is, by the concentration step of the present embodiment, a concentrated liquid UFB4 in which the number density of the bubbles 21A, which are ultra-fine bubbles, is concentrated is obtained. Concentrated liquid UFB4 is an ultra-fine bubble concentrated liquid in which the number density of ultra-fine bubbles is concentrated compared to the first liquid UFB3 shown in FIG.

In addition, in the case of this modification, since the accommodating portion 45 itself rotates, the inner surface 46 of the accommodating portion 45 is cooled over a wide range. The point that the solidified film 31 is formed on the portion including the bottom surface 46b of the inner surface 46 of the accommodating portion 45 is the same as the example described with reference to FIG. However, in the case of this modification, the area of the portion of the inner surface 46 where the solidified film 31 is formed is wider than in the example shown in FIG.

In particular, in the case of the example shown in FIG. 8, the rotation axis VL2 is inclined at an angle of less than 90 degrees with respect to the liquid surface UFBt of the first liquid UFB3 when it is stationary in the container 45. As shown in FIG. In the example shown in FIG. 8, the rotation axis VL2 is inclined at an angle of about 30 degrees with respect to the liquid surface UFBt of the first liquid UFB3 when it is stationary in the container 45. In the example shown in FIG. In this case, since the area of the portion of the containing portion 45 that is immersed in the coolant 61 is increased, the area of the portion where the solidified film 31 is formed can be increased. If the area of the portion where the solidified film 31 is formed can be increased as in this modified example, the concentration efficiency in one concentration step can be improved.

The separating step shown in FIG. 2 can be applied by replacing the portion described as the accommodating portion 40 with the accommodating portion 45 in the embodiment described using FIG. Therefore, overlapping explanations are omitted.

Concentrated liquid UFB4, which is an ultra-fine bubble concentrated liquid, is obtained by the above steps. Since the solidified film 31 remaining in the storage section 45 can be easily liquefied by heating, for example, it is preferably removed from the storage section 45 after the liquefaction process.

In the case of this modification, as shown in FIG. 9, the liquid 30 is stirred by the rotation of the container 45, so that the solidified film 31 and the stirring blades 52 are separated from each other like the concentrator 100 described with reference to FIG. No contact concerns. Therefore, the next concentration step can be performed without removing the remaining solidified film 31 . In other words, in the case of this modification, when an ultra-fine bubble concentrate with a higher concentration rate than the concentrate UFB4 is required, ultra-fine bubbles in the ultra-fine bubble concentrate obtained by controlling the time of the concentration process The bubble number density can be controlled. Alternatively, the concentration step can be repeated multiple times before the separation step is performed. This modification will be described later.

<Modified Example of Concentration Process>
Next, a modification of the concentration process shown in FIG. 2 will be described. FIG. 10 is an explanatory diagram showing a modification of the flow shown in FIG. FIG. 11 is a cross-sectional view showing the state after the first liquid adding step shown in FIG. 12 is a cross-sectional view showing the state after the second concentration step shown in FIG. 10. FIG. The method for producing an ultra-fine bubble concentrate shown in FIG. 10 differs from the method for producing an ultra-fine bubble concentrate shown in FIG. 2 in the concentration step. In the method for producing an ultra-fine bubble concentrate shown in FIG. 10, the concentration step includes a first concentration step, a first liquid addition step, and a second concentration step.

In the case of this modification, the first liquid UFB1 shown in FIG. 3 or the first liquid UFB3 shown in FIG. 7 is prepared. In the case of this modification, a large amount of ultra-fine bubble concentrated liquid can be produced compared to the method shown in FIG. 2, so a large amount of the first liquid UFB1 or UFB3 is prepared accordingly. The manufacturing method shown in FIG. 10 can be applied to both the embodiment described using FIGS. 3-5 and the embodiment described using FIGS. 7-9. In the following, as a representative example, the case of applying the example described with reference to FIGS. 7 to 9 will be described.

In the first concentration step, part of the first liquid UFB3 shown in FIG. 7 is contained in the container 45 shown in FIG. This is a step of selectively solidifying the fluid 11 contained in a portion of the first liquid UFB3 (the portion contained in the container 45) by cooling while stirring to obtain a concentrated liquid UFB4 (see FIG. 9). The processing in this step is the same as the concentration step described with reference to FIGS. 8 and 9, so redundant description will be omitted. In the case of this modification, the first concentration step is an intermediate stage of the concentration step, so the concentrated liquid UFB4 is not a final product but an intermediate product.

The first liquid adding step is a step of supplying another part of the first liquid UFB3 shown in FIG. . The first liquid adding step is performed with the concentrated liquid UFB4 shown in FIG. Therefore, although the concentrated liquid UFB4 is diluted, the number density of ultra-fine bubbles in the second liquid UFB5 shown in FIG. 11 is higher than the number density of ultra-fine bubbles in the first liquid UFB3 shown in FIG.

In the second concentration step, after the first liquid addition step, the second liquid UFB5 shown in FIG. The fluid 11 contained in is selectively solidified to obtain a concentrate UFB6 shown in FIG.

The separating step shown in FIG. 10 can be applied by replacing the portion described as the accommodating portion 40 with the accommodating portion 45 in the embodiment described using FIG. Therefore, overlapping explanations are omitted.

As in this modification, in the concentration step, by performing the concentration process multiple times, compared to the method of concentrating the first liquid UFB3 at once, the ultra-fine bubbles in the finally obtained ultra-fine bubble concentrated liquid can increase the number density of

Note that FIG. 10 describes an embodiment including two concentration steps between the first liquid preparation step and the separation step. However, the number of concentration steps included between the first liquid preparation step and the separation step is not limited to two, and may be three or more.

In addition, although this modified example has been described as a modified example of the embodiment described using FIGS. 7 to 9, it can also be applied as a modified example of the example described using FIGS. However, in the case of the concentrating device 100 shown in FIG. 5, if the solidified film 31 comes into contact with the stirring blades 52, it becomes difficult to perform a sufficient stirring process. On the other hand, in the case of the concentrating device 101 shown in FIG. 8, no member for agitation is arranged in the accommodating section 45, so there are no restrictions like the concentrating device 100. FIG. Therefore, it is particularly effective to apply this modified example to the concentrating device 101 shown in FIG.

Moreover, as an application of this modified example, the following modified examples are conceivable. That is, in the flow shown in FIG. 10, there is a method of forming a solidified film 31 made of a solidified substance of the fluid 11 on the inner surface 46 of the containing portion 45 before the concentration process starts. For example, if the liquid 30 contains a plurality of materials other than the fluid 11, and if the freezing points of some of the plurality of materials are close to the freezing point of the fluid 11, the materials will be included in the solidified film 31 in the concentration process. Sometimes.

In the case where the solidified film 31 made of the solidified substance of the fluid 11 is formed on the inner surface 46 of the storage portion 45 before the concentration process starts, the wettability of the liquid 30 to the fluid 11 is particularly high. Even if the liquid 30 contains a substance that is easily coagulated, the fluid 11 can easily be selectively solidified.

This modification can also be applied to the manufacturing flow shown in FIG. 2 and the manufacturing flow described with reference to FIGS. That is, in the concentrating apparatus shown in FIG. 5, when the solidified film 31 made of the solidified substance of the fluid 11 is formed in advance on the inner surface 41 of the container 40, the wettability of the liquid 30 to the fluid 11 is particularly high. , the fluid 11 can easily be selectively coagulated even when the liquid 30 contains a substance that easily coagulates.

The present invention is not limited to the above embodiments and examples, and can be modified in various ways without departing from the scope of the invention. For example, in the above description, an example in which air is used as the second fluid and water is used as the first fluid, and an example in which a flavor is added to the first fluid are described. can apply various modifications. As the second fluid, for example, an inert gas such as nitrogen or a rare gas, or a fluid containing radical molecules such as ozone can be used. As the first fluid, for example, fuel-based oil and food-based oil can be exemplified. Further, for example, various modifications have been described above, but a part of the embodiment can be applied in combination with another embodiment.

INDUSTRIAL APPLICABILITY The present invention can be used for ultra-fine bubble liquids used in various industrial fields.

10: Liquid, 10t, UFBt: Liquid level, 11: Fluid (first fluid), 12: Volatile substance, 20: Bubbles, 20A: Ultra fine bubbles, 20B: Non-ultra fine bubbles, 21: Fluid (second fluid ), 21A: Bubbles, 30: Liquid, 31: Solidified film, 40, 45: Storage part, 41, 46: Inner surface, 41b, 46b: Bottom surface, 41s: Side surface, 50: Stirring mechanism part, 51: Rotating shaft, 52 : stirring blade, 53: motor (driving unit), 60: cooling mechanism unit, 61: refrigerant, 62: bathtub, 62A: supply port, 62B: discharge port, 100, 101: concentrator, D1, D2: bubble diameter, UFB1, UFB3: first liquid, UFB2, UFB4, UFB6: concentrated liquid, UFB5: second liquid VL1, VL2: rotating shaft

Claims (8)

(a) a first fluid comprising a first fluid in a liquid state and a second fluid in a gaseous state, wherein bubbles of the second fluid having a diameter of less than 1 μm are mixed in the first fluid at a first number density; A step of preparing a liquid,
(b) selectively solidifying the first fluid by cooling the first liquid while stirring;
(c) the bubbles of the second fluid in the first fluid solidified in the step (b) and the first fluid that did not solidify at a second number density higher than the first number density; separating the mixed concentrate;
A method for producing an ultra-fine bubble concentrate, comprising: In claim 1,
The step (b) is carried out in an ultra-fine bubble liquid concentrator,
The ultra-fine bubble liquid concentrator,
a container for containing the first liquid;
a stirring mechanism part capable of stirring the first liquid in the storage part;
a cooling mechanism part capable of cooling the first liquid in the storage part;
with
The method for producing an ultra-fine bubble concentrate, wherein in the step (b), the solidified first fluid is formed as a solidified film on the inner surface of the container. In claim 2,
The stirring mechanism part of the concentrator is
a rotating shaft that rotates within the housing;
a stirring blade attached to the rotating shaft;
a motor that drives the rotating shaft;
A method for producing an ultra-fine bubble concentrate, comprising: In claim 2,
the inner surface of the accommodating portion on which the solidified film is formed in the step (b) is a curved surface;
The stirring mechanism of the concentrator includes a drive unit connected to the storage unit in a state capable of driving the storage unit to rotate about a first rotation axis,
In the step (b), in a state in which a portion of the containing portion is cooled by the cooling mechanism portion, the containing portion itself rotates, thereby agitating the first liquid in the containing portion, ultra-fine bubbles. A method for producing a concentrate. 5. The method for producing an ultra-fine bubble concentrated liquid according to claim 4, wherein the first rotating shaft is inclined at an angle of less than 90 degrees with respect to the surface of the first liquid when it is stationary in the container. In claim 4,
The step (b) is
(b1) cooling a portion of the first liquid while stirring the portion of the first liquid in a state in which the portion of the first liquid is contained in the containing portion; selectively solidifying the fluid to obtain a first concentrate;
(b2) after the step (b1), supplying another part of the first liquid to the first concentrated liquid in the container to form a second liquid;
(b3) after the step (b2), by cooling the second liquid while stirring, the first fluid contained in the second liquid is selectively solidified to obtain a second concentrated liquid; ,
A method for producing an ultra-fine bubble concentrate, comprising: In claim 1,
A method for producing an ultra-fine bubble concentrated liquid, wherein a volatile substance having a boiling point lower than that of the first fluid is dissolved in the first liquid. In claim 2,
A method for producing an ultra-fine bubble concentrate, wherein a first solidified film made of a solidified substance of the first fluid is formed on the inner surface of the storage portion before starting the step (b).

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