阅读说明：本技术 微小气泡生成方法和微小气泡生成装置 (Method and apparatus for generating fine bubbles ) 是由 藤田勇仁 小林正史 切石壮 于 2018-12-25 设计创作，主要内容包括：本发明提供一种能在液体中高效生成直径为纳米级的微小气泡的微小气泡生成方法和装置。微小气泡生成装置包括：储液槽(10)；将储存在储液槽(10)中的液体吸起并送出的送液机构(20)；对送液机构(20)送液途中的液体释放气体的气体释放机构(30)；将由气体释放机构(30)释放有气体的液体加以储存的储液槽(40)。气体释放机构(30)具有：在气体释放面开口有孔径(众数径)为1.5μm以下的大量气体释放孔的气体释放部件(32)；和在与气体释放部件(32)的气体释放面的接触面形成有槽的基底部件,送液机构(20)以使液体与气体释放部件(32)的相对速度成为1m/sec以上的方式,使该液体在由气体释放部件(32)的气体释放面和基底部件(31)的槽包围的流路FC中流动,从而使液体沿着气体释放部件(32)的气体释放面移动。(The present invention provides a method and an apparatus for generating fine bubbles capable of efficiently generating fine bubbles having a diameter of a nanometer order in a liquid. The microbubble generation device includes: a reservoir (10); a liquid feeding mechanism (20) for sucking up and feeding out the liquid stored in the liquid storage tank (10); a gas release mechanism (30) for releasing gas to the liquid during the liquid feeding of the liquid feeding mechanism (20); a reservoir tank (40) for storing the liquid in which the gas is released by the gas release mechanism (30). The gas release mechanism (30) comprises: a gas release member (32) having a plurality of gas release holes with a pore diameter (mode diameter) of 1.5 μm or less opened on a gas release surface; and a base member having a groove formed in a contact surface with the gas release surface of the gas release member (32), wherein the liquid feeding mechanism (20) moves the liquid along the gas release surface of the gas release member (32) by causing the liquid to flow through a flow channel FC surrounded by the gas release surface of the gas release member (32) and the groove of the base member (31) so that the relative speed of the liquid and the gas release member (32) becomes 1m/sec or more.)

1. A method for generating fine bubbles having a diameter of a nanometer order in a liquid, the method comprising:

bringing a liquid into contact with a gas discharge surface of a gas discharge member, the gas discharge surface having a plurality of gas discharge holes with a pore diameter (mode diameter) of 1.5[ mu ] m or less;

and releasing the gas from the gas releasing member into the liquid while relatively moving the liquid along the gas releasing surface of the gas releasing member so that the relative speed with the gas releasing member becomes 1m/sec or more.

2. The method of generating fine bubbles according to claim 1, wherein:

the pore size distribution of the gas release pores satisfies (D90-D10)/D50 of 3.0 or less, where D10 represents a pore size where the cumulative number of pores from the small diameter side is 10% of the total number of pores, D50 represents a pore size where the cumulative number of pores from the small diameter side is 50% of the total number of pores, and D90 represents a pore size where the cumulative number of pores from the small diameter side is 90% of the total number of pores.

3. The method of producing fine bubbles according to claim 1 or 2, wherein:

the liquid is moved along the gas discharge surface of the gas discharge member by disposing the gas discharge member in the flow of the liquid.

4. The method of producing fine bubbles according to claim 1 or 2, wherein:

a liquid flow path is provided on the gas discharge surface of the gas discharge member in a state where the liquid is in contact with the gas discharge surface, and the liquid is moved along the gas discharge surface of the gas discharge member by flowing the liquid through the flow path.

5. The method of producing fine bubbles according to claim 1 or 2, wherein:

the gas discharge member has a cylindrical shape or a cylindrical shape having the gas discharge holes opened on an outer peripheral surface as a gas discharge surface,

the gas release member in a cylindrical shape or a cylindrical shape is rotated at a fixed position around an axial center in a state of being immersed in a stationary liquid.

6. A fine bubble generating apparatus for generating fine bubbles having a diameter of a nanometer order in a liquid, the apparatus comprising:

a gas release mechanism having a gas release member having a plurality of gas release holes opened in a gas release surface; and

a relative movement unit that relatively moves the liquid along the gas discharge surface of the gas discharge member,

the pore diameter (mode diameter) of the gas release holes of the gas release member is 1.5[ mu ] m or less,

the relative movement means relatively moves the liquid along the gas discharge surface of the gas discharge member so that the relative speed between the liquid and the gas discharge member becomes 1m/sec or more, and discharges the gas from the gas discharge member into the liquid.

7. The microbubble generator according to claim 6, wherein:

the pore size distribution of the gas release pores satisfies (D90-D10)/D50 of 3.0 or less, where D10 represents a pore size where the cumulative number of pores from the small diameter side is 10% of the total number of pores, D50 represents a pore size where the cumulative number of pores from the small diameter side is 50% of the total number of pores, and D90 represents a pore size where the cumulative number of pores from the small diameter side is 90% of the total number of pores.

8. The microbubble generator according to claim 6 or 7, wherein:

the gas release mechanism includes a flow path forming member that is attached in a state of surface contact with a gas release surface of the gas release member and has a groove formed on a contact surface with the gas release surface of the gas release member,

the relative movement means causes the liquid to flow through a flow path surrounded by the gas discharge surface of the gas discharge member and the groove of the flow path forming member, thereby moving the liquid along the gas discharge surface of the gas discharge member.

9. The microbubble generator according to claim 6 or 7, wherein:

the gas discharge member has a cylindrical shape or a cylindrical shape having the gas discharge holes opened on an outer peripheral surface as a gas discharge surface,

the relative movement means rotates the gas discharge member in a fixed position around an axis, the gas discharge member being in a cylindrical shape or a cylinder shape in a state of being immersed in a stationary liquid.

Technical Field

The present invention relates to a method and an apparatus for generating fine bubbles having a diameter of a nanometer order in a liquid.

Background

Patent document 1, for example, discloses a method for generating fine bubbles in a liquid. The method for generating fine bubbles comprises immersing a porous body having a large number of gas release holes with a pore diameter of 5 μm in a liquid stored in a storage tank, supplying bubbles to the liquid by releasing gas from the porous body, applying vibration of the porous body at a frequency of 1kHz or less in a direction substantially perpendicular to a release direction of the bubbles, and applying vibration of the porous body at a frequency of 1kHz or less in a direction substantially perpendicular to the release direction of the bubbles, whereby the bubbles released from the porous body are made fine by shear force, and the fine bubbles can be generated in the liquid.

Disclosure of Invention

Technical problem to be solved by the invention

However, in the method for generating fine bubbles described in patent document 1, the pore diameter of the gas release pores of the porous body for supplying the bubbles is relatively large, and fine bubbles (microbubbles) having a bubble diameter of about several tens μm to several hundreds μm can be generated, but fine bubbles having a bubble diameter of a nanometer order cannot be generated.

Further, in order to apply vibration having a frequency of 1kHz or less to the porous body in a direction substantially perpendicular to the direction of release of the bubbles, an excitation device capable of arbitrarily setting the frequency and amplitude of the generated vibration and a vibration transmission member for transmitting the vibration generated by the excitation device to the porous body immersed in the liquid are required, and there is a problem that an apparatus for carrying out the method for generating fine bubbles cannot be made compact and downsized.

Accordingly, an object of the present invention is to provide a method and an apparatus for generating fine bubbles, which can efficiently generate fine bubbles having a diameter of a nanometer order in a liquid.

Means for solving the problems

In order to solve the above problem, the invention according to claim 1 provides a fine bubble generation method for generating fine bubbles having a diameter of a nanometer order in a liquid, the fine bubble generation method comprising: bringing a liquid into contact with a gas discharge surface of a gas discharge member, the gas discharge surface having a plurality of gas discharge holes with a pore diameter (mode diameter) of 1.5[ mu ] m or less; the gas is released from the gas releasing member into the liquid while relatively moving the liquid along the gas releasing surface of the gas releasing member so that the relative speed with the gas releasing member becomes 1[ m/sec ] or more.

The invention of claim 2 is characterized in that, in the microbubble generation method of the invention of claim 1, the pore size distribution of the gas release pores satisfies (D90-D10)/D50 ≦ 3.0, when the pore size at which the cumulative pore number from the small diameter side becomes 10% of the total pore number is D10, the pore size at which the cumulative pore number from the small diameter side becomes 50% of the total pore number is D50, and the pore size at which the cumulative pore number from the small diameter side becomes 90% of the total pore number is D90.

The invention of claim 3 is the method for generating fine bubbles according to the invention of claim 1 or claim 2, wherein the gas releasing member is disposed in a liquid flow, and the liquid is moved along the gas releasing surface of the gas releasing member.

The invention of claim 4 is the method for generating fine bubbles of the invention of claim 1 or claim 2, wherein a liquid flow path is provided on the gas emitting surface of the gas emitting member in a state where the liquid is in contact with the gas emitting surface, and the liquid is moved along the gas emitting surface of the gas emitting member by flowing through the liquid flow path.

The invention according to claim 5 is the method for producing fine bubbles according to the invention according to claim 1 or claim 2, wherein the gas discharge member has a cylindrical shape or a cylindrical shape having the gas discharge holes opened on an outer peripheral surface thereof as a gas discharge surface, and the gas discharge member in the cylindrical shape or the cylindrical shape is rotated (reversed in position) around an axis as a center in a state of being immersed in the stationary liquid.

Further, the invention of claim 6 is a microbubble generator for generating microbubbles having a diameter of a nanometer order in a liquid, the apparatus comprising: a gas release mechanism having a gas release member having a large number of gas release holes opened in a gas release surface; and a relative movement means for relatively moving a liquid along the gas discharge surface of the gas discharge member, wherein the aperture diameter (mode diameter) of the gas discharge holes of the gas discharge member is 1.5[ mu ] m or less, and the relative movement means relatively moves the liquid along the gas discharge surface of the gas discharge member so that the relative velocity between the liquid and the gas discharge member is 1[ m/sec ] or more, and discharges the gas from the gas discharge member into the liquid.

The invention of claim 7 is characterized in that, in the microbubble generator of the invention of claim 6, the pore size distribution of the gas release pores satisfies (D90-D10)/D50 ≤ 3.0, where D10 represents a pore size where the cumulative pore size from the small diameter side is 10% of the total pore size, D50 represents a pore size where the cumulative pore size from the small diameter side is 50% of the total pore size, and D90 represents a pore size where the cumulative pore size from the small diameter side is 90% of the total pore size.

The invention of claim 8 is the microbubble generation device of claim 6 or claim 7, wherein the gas release member includes a flow path forming member that is attached in surface contact with the gas release surface of the gas release member and has a groove formed on a contact surface with the gas release surface of the gas release member, and the relative movement means moves the liquid along the gas release surface of the gas release member by causing the liquid to flow through a flow path surrounded by the gas release surface of the gas release member and the groove of the flow path forming member.

The invention according to claim 9 is the microbubble generator according to claim 6 or claim 7, wherein the gas discharge member has a cylindrical shape or a cylindrical shape having the gas discharge holes opened in an outer peripheral surface as a gas discharge surface, and the relative movement means rotates the gas discharge member in the cylindrical shape or the cylindrical shape immersed in the stationary liquid at a fixed position around the axis.

Effects of the invention

As described above, in the method for generating fine bubbles of the invention of claim 1 and the apparatus for generating fine bubbles of the invention of claim 6, the gas released from the gas release holes having a hole diameter (mode diameter) of 1.5[ μm ] or less is divided into fine bubbles having a bubble diameter of 1.5 μm or less and released into the liquid by relatively moving the liquid along the gas release surface of the gas release member so that the relative velocity becomes 1[ m/sec ] or more and releasing the gas from the gas release member into the liquid, and the fine bubbles in the liquid are gradually contracted to generate fine bubbles having a nanometer order. Therefore, it is not necessary to provide a vibration applying means for applying vibration to the gas releasing member as in the conventional art, and the microbubble generator can be made compact and small.

In the method for producing fine bubbles according to the invention of claim 2 and the apparatus for producing fine bubbles according to the invention of claim 7, the pore diameter distribution of the gas release pores satisfies (D90-D10)/D50 ≦ 3.0 when the pore diameter from the small-diameter side where the cumulative pore count is 10% of the total pore count is D10, the pore diameter from the small-diameter side where the cumulative pore count is 50% of the total pore count is D50, and the pore diameter from the small-diameter side where the cumulative pore count is 90% of the total pore count is D90, and therefore, a large amount of nano-sized fine bubbles having small pore diameter variation and small bubble diameter variation can be produced.

Further, in order to relatively move the liquid along the bubble discharging surface of the bubble discharging member, as in the method for generating fine bubbles of the invention of claim 3, the liquid is moved along the gas discharging surface of the gas discharging member by disposing the gas discharging member in the liquid flow, or as in the method for generating fine bubbles of the invention of claim 4, a flow path for the liquid is provided on the gas discharging surface of the gas discharging member in a state where the liquid is in contact with the gas discharging surface, and the liquid is moved along the gas discharging surface of the gas discharging member by flowing the liquid in the flow path, or as in the method for generating fine bubbles of the invention of claim 5 and the apparatus for generating fine bubbles of the invention of claim 9, the gas discharging member having a cylindrical shape or a cylindrical shape is rotated at a fixed position with the axial core as the center in a state of being immersed in the stationary liquid, the gas release member has gas release holes opened in an outer peripheral surface as a gas release surface.

In particular, when the flow path of the liquid is provided on the gas discharge surface of the gas discharge member in a state where the liquid is in contact with the gas discharge surface, as in the fine bubble generating device according to the invention of claim 8, the flow path forming member having the groove formed on the contact surface with the gas discharge surface of the gas discharge member is attached to the gas discharge head in a state where the flow path forming member is in surface contact with the gas discharge surface of the gas discharge member, whereby a portion surrounded by the gas discharge surface of the gas discharge member and the groove of the flow path forming member can be used as the flow path.

Drawings

FIG. 1 is a schematic configuration diagram showing one embodiment of a microbubble generator according to the present invention.

FIG. 2 is a plan view showing a gas release mechanism of the microbubble generator mounted thereon.

FIG. 3 is a bottom view showing the gas release mechanism of the same.

Fig. 4 is a sectional view taken along line X-X of fig. 2.

FIG. 5 is an exploded sectional view showing the gas release mechanism as above.

FIG. 6 is a plan view showing a base member constituting the gas release mechanism of the same.

Fig. 7(a) and (b) are schematic diagrams showing a modified pattern of a flow path provided on a gas discharge surface of a gas discharge member constituting a gas discharge mechanism.

Fig. 8 is a perspective view showing a modification of the above-described gas release member.

Fig. 9(a) and (b) are schematic diagrams showing a modification of the gas release mechanism using a cylindrical gas release member.

Fig. 10 is a schematic view showing another modification of the gas release mechanism using a cylindrical gas release member.

FIG. 11 is a schematic view showing a microbubble generator according to another embodiment of the microbubble generator described above.

FIG. 12 is a schematic configuration diagram showing another embodiment of the microbubble generator as described above.

FIG. 13 is a schematic configuration diagram showing another embodiment of the microbubble generator as described above.

FIG. 14 is a schematic configuration diagram showing another embodiment of the microbubble generator as described above.

Detailed Description

Hereinafter, embodiments will be described with reference to the drawings. FIG. 1 shows a schematic configuration of a microbubble generator according to the present invention. As shown in the figure, the microbubble generator 1 includes: a reservoir 10 for storing liquid; a liquid feeding mechanism (relative movement means) 20 for sucking up and feeding out the liquid stored in the liquid reservoir 10; a gas releasing mechanism 30 for releasing gas from the liquid being fed by the liquid feeding mechanism 20; and a reservoir 40 for storing the liquid after the gas is released from the gas release mechanism 30.

As shown in the drawing, the liquid feeding mechanism 20 includes: a liquid sending tube 21 and a liquid sending tube 22 forming a liquid flow path; a variable flow rate type liquid sending pump 23 provided in the liquid sending pipe 22; and a valve 24 provided in a portion of the liquid sending pipe 21 for adjusting a negative pressure of the gas releasing mechanism 30, the liquid stored in the liquid reservoir 10 is sent out to the liquid reservoir 40 through the gas releasing mechanism 30.

As shown in fig. 1 to 6, the gas release mechanism 30 includes: a base member (flow path forming member) 31 formed of a resin molded product, having a spiral groove 31b formed in a circular recess bottom surface 31 a; a disk-shaped gas releasing member 32 disposed with its lower surface (gas releasing surface) in contact with the bottom surface 31a of the recess of the base member 31; an annular gasket 33 disposed so as to be in surface contact with a peripheral edge portion of an upper surface of the disk-shaped gas releasing member 32; and a circular cap 34 formed of a resin molded product and fitted in the recess of the base member 31 in a state where the annular packing 33 is pressed downward, wherein a liquid flow path FC is formed by the spiral groove 31b and the lower surface (gas release surface) of the gas release member 32 in a state where the liquid is in contact with the lower surface (gas release surface) of the gas release member 32, and an air supply chamber GR is formed between the upper surface of the gas release member 32 and the lower surface of the cap 34 by the annular packing 33. The grid portion in fig. 6 shows a spiral groove 31 b.

As shown in fig. 5 and 6, a screw hole 31c vertically penetrating the center side end of the spiral groove 31b is formed in the base member 31, and the downstream side end of the liquid sending tube 21 of the liquid sending mechanism 20 is connected to the gas release mechanism 30 via a pipe joint 35 screwed into the screw hole 31 c.

A bamboo-shoot-shaped pipe joint 31d connected to the upstream end of the liquid sending pipe 22 of the liquid sending mechanism 20 is integrally formed on the side surface of the base member 31, and a flow path 31e connecting the pipe joint 31d and the outer end of the spiral groove 31b is formed inside the base member 31.

Therefore, the liquid stored in the reservoir 10 is sent from the liquid sending tube 21 of the liquid sending mechanism 20 to the gas releasing mechanism 30, sent to the liquid sending tube 22 of the liquid sending mechanism 20 through the flow path FC and the flow path 31e of the base member 31, and sent from the liquid sending tube 22 to the reservoir 40.

The gas release member 32 is formed of a gas-permeable porous body made of porous ceramics such as porous alumina and porous glass, and a large number of gas release holes having a pore diameter (モード diameter: mode diameter) of 1.5[ mu ] m or less are opened in the lower surface. Specifically, of 6 kinds of the gas release holes having pore diameters (mode diameters) of 1.5 μm, 1 μm, 0.8 μm, 0.4 μm, 0.05 μm, and 0.005 μm, a total of 12 kinds of the gas release members 32 having 2 pore diameter distributions were used for the respective pore diameters. Further, regarding the pore diameter distribution of the gas release pores, when the pore diameter at which the cumulative pore number from the small diameter side becomes 10% of the total pore number is D10, the pore diameter at which the cumulative pore number from the small diameter side becomes 50% of the total pore number is D50, and the pore diameter at which the cumulative pore number from the small diameter side becomes 90% of the total pore number is D90, the evaluation was made based on the value of (D90-D10)/D50. It is considered that the small value of the difference in pore diameter is small, and the large value is large. The values of the pore diameters (mode diameters) of the gas release holes of each gas releasing member 32, D10, D50, and D90 were determined by measuring 3 pore diameter distributions of a test piece (20mm × 5mm) cut out from each gas releasing member 32 by a gas adsorption method using a pore diameter distribution measuring instrument (POROUS alumina: Perm-Porometer manufactured by POROUS MATERIALS, usa, and Nano-PermPoro meter manufactured by seikawa digital image co.

A screw hole 34a penetrating the center of the lid 34 vertically is formed, and a gas supply pipe for supplying various gases to the gas supply chamber GR can be connected through a pipe joint 36 screwed to the screw hole 34 a. In each of the embodiments described later, air is used as the gas, and therefore the pipe joint 36 is opened to the atmosphere without particularly connecting an air supply pipe.

In the microbubble generation device 1 configured as described above, when the liquid is introduced into the reservoir 10 and the liquid-sending pump 23 is operated, the liquid in the reservoir 10 is sent to the reservoir 40 through the flow path FC of the gas release mechanism 30, and the inside of the flow path FC of the gas release mechanism 30 on the suction side of the liquid-sending pump 23 is at a negative pressure, and therefore air is sucked out into the liquid passing through the flow path FC from the gas release hole of the gas release member 32 opened on the lower surface by the negative pressure. When the pump flow rate is adjusted so that the flow rate of the liquid in the flow path FC of the gas release mechanism 30 becomes 1[ m/sec ] or more, the air sucked out of the gas release hole of the gas release member 32 into the liquid passing through the flow path FC is divided into fine bubbles of 1.5 μm or less by the flow of the liquid flowing through the flow path FC, the fine bubbles gradually contract to generate fine bubbles of nanometer order, and the liquid containing the fine bubbles of nanometer order is stored in the reservoir 40.

Hereinafter, examples 1 to 19 of the present invention and comparative examples 1 to 7 for generating fine bubbles of air in pure water by using the above-described fine bubble generating apparatus 1 will be described with reference to table 1, but the present invention is not limited to the following examples.

(example 1)

As shown in table 2, as the gas release means 32 of the gas release mechanism 30, pure water was introduced into the reservoir 10 using a means in which the hole diameter (mode diameter) of the gas release hole was 1.5 μm and the hole diameter distribution (D90-D10)/D50 was 2.898, and the liquid-sending pump 23 was operated in a state in which the pump flow rate was adjusted so that the flow rate in the flow channel FC of the gas release mechanism 30 became 2[ m/sec ], thereby generating fine bubbles of air in the pure water.

(example 2)

As shown in Table 2, fine bubbles of air were generated in pure water in the same manner as in example 1, except that the gas release member 32 of the gas release mechanism 30 was a member having 1 μm pore diameter (mode diameter) of the gas release pores and 2.591 pore diameter distribution (D90-D10)/D50.

(example 3)

As shown in table 2, fine bubbles of air were generated in pure water in the same manner as in example 1, except that the gas release member 32 of the gas release mechanism 30 was a member in which the pore diameter (mode diameter) of the gas release pores was 0.8 μm and the pore diameter distribution (D90-D10)/D50 was 2.268.

(example 4)

As shown in table 2, fine bubbles of air were generated in pure water in the same manner as in example 1, except that the gas release member 32 of the gas release mechanism 30 was a member in which the pore diameter (mode diameter) of the gas release pores was 0.4 μm and the pore diameter distribution (D90-D10)/D50 was 1.553.

(example 5)

As shown in table 2, fine bubbles of air were generated in pure water in the same manner as in example 1, except that the gas release member 32 of the gas release mechanism 30 was a member in which the pore diameter (mode diameter) of the gas release pores was 0.05 μm and the pore diameter distribution (D90-D10)/D50 was 1.206.

(example 6)

As shown in Table 2, fine bubbles of air were generated in pure water in the same manner as in example 1, except that the gas release member 32 of the gas release mechanism 30 was a member in which the pore diameter (mode diameter) of the gas release pores was 0.005 μm and the pore diameter distribution (D90-D10)/D50 was 1.025.

(example 7)

As shown in table 2, fine bubbles of air were generated in pure water in the same manner as in example 4, except that the pump flow rate was adjusted so that the flow rate in the flow channel FC of the gas release mechanism 30 became 1[ m/sec ].

(example 8)

As shown in table 2, fine bubbles of air were generated in pure water in the same manner as in example 4, except that the pump flow rate was adjusted so that the flow rate in the flow channel FC of the gas release mechanism 30 became 3[ m/sec ].

(example 9)

As shown in table 2, fine bubbles of air were generated in pure water in the same manner as in example 4, except that the pump flow rate was adjusted so that the flow rate in the flow channel FC of the gas release mechanism 30 became 5[ m/sec ].

(example 10)

As shown in table 2, fine bubbles of air were generated in pure water in the same manner as in example 4, except that the pump flow rate was adjusted so that the flow rate in the flow channel FC of the gas release mechanism 30 became 10[ m/sec ].

(example 11)

As shown in table 2, fine bubbles of air were generated in pure water in the same manner as in example 1, except that the gas release member 32 of the gas release mechanism 30 was a member in which the pore diameter (mode diameter) of the gas release pores was 1.5 μm and the pore diameter distribution (D90-D10)/D50 was 8.474.

(example 12)

As shown in table 2, fine bubbles of air were generated in pure water in the same manner as in example 2, except that the gas release member 32 of the gas release mechanism 30 was a member in which the pore diameter (mode diameter) of the gas release holes was 1 μm and the pore diameter distribution (D90-D10)/D50 was 9.611.

(example 13)

As shown in table 2, fine bubbles of air were generated in pure water in the same manner as in example 3, except that the gas release member 32 of the gas release mechanism 30 was a member in which the pore diameter (mode diameter) of the gas release pores was 0.8 μm and the pore diameter distribution (D90-D10)/D50 was 4.893.

(example 14)

As shown in table 2, fine bubbles of air were generated in pure water in the same manner as in example 4, except that the gas release member 32 of the gas release mechanism 30 was a member in which the pore diameter (mode diameter) of the gas release pores was 0.4 μm and the pore diameter distribution (D90-D10)/D50 was 7.474.

(example 15)

As shown in table 2, fine bubbles of air were generated in pure water in the same manner as in example 5, except that the gas release member 32 of the gas release mechanism 30 was a member in which the pore diameter (mode diameter) of the gas release pores was 0.05 μm and the pore diameter distribution (D90-D10)/D50 was 3.980.

(example 16)

As shown in table 2, fine bubbles of air were generated in pure water in the same manner as in example 7, except that the gas release member 32 of the gas release mechanism 30 was a member in which the pore diameter (mode diameter) of the gas release pores was 0.4 μm and the pore diameter distribution (D90-D10)/D50 was 7.474.

(example 17)

As shown in table 2, fine bubbles of air were generated in pure water in the same manner as in example 8, except that the gas release member 32 of the gas release mechanism 30 was a member in which the pore diameter (mode diameter) of the gas release pores was 0.4 μm and the pore diameter distribution (D90-D10)/D50 was 7.474.

(example 18)

As shown in table 2, fine bubbles of air were generated in pure water in the same manner as in example 9, except that the gas release member 32 of the gas release mechanism 30 was a member in which the pore diameter (mode diameter) of the gas release pores was 0.4 μm and the pore diameter distribution (D90-D10)/D50 was 7.474.

(example 19)

As shown in table 2, fine bubbles of air were generated in pure water in the same manner as in example 10, except that the gas release member 32 of the gas release mechanism 30 was a member in which the pore diameter (mode diameter) of the gas release pores was 0.4 μm and the pore diameter distribution (D90-D10)/D50 was 7.474.

Comparative example 1

As shown in table 2, as the gas release means 32 of the gas release mechanism 30, pure water was introduced into the reservoir 10 using a means in which the pore diameter (mode diameter) of the gas release hole was 2 μm and the pore diameter distribution (D90-D10)/D50 was 2.734, and the liquid feed pump 23 was operated in a state in which the pump flow rate was adjusted so that the flow rate in the flow channel FC of the gas release mechanism 30 became 5[ m/sec ], thereby generating fine bubbles of air in the pure water.

Comparative example 2

As shown in table 2, fine bubbles of air were generated in pure water in the same manner as in comparative example 1, except that the gas release member 32 of the gas release mechanism 30 was a member in which the pore diameter (mode diameter) of the gas release pores was 2.5 μm and the pore diameter distribution (D90-D10)/D50 was 2.649.

Comparative example 3

As shown in table 2, fine bubbles of air were generated in pure water in the same manner as in comparative example 1, except that the gas release member 32 of the gas release mechanism 30 was a member in which the pore diameter (mode diameter) of the gas release holes was 5 μm and the pore diameter distribution (D90-D10)/D50 was 2.981.

Comparative example 4

As shown in table 2, fine bubbles of air were generated in pure water in the same manner as in example 4, except that the pump flow rate was adjusted so that the flow rate in the flow channel FC of the gas release mechanism 30 became 0.8[ m/sec ].

Comparative example 5

As shown in table 2, fine bubbles of air were generated in pure water in the same manner as in example 4, except that the pump flow rate was adjusted so that the flow rate in the flow channel FC of the gas release mechanism 30 became 0.5[ m/sec ].

Comparative example 6

As shown in table 2, fine bubbles of air were generated in pure water in the same manner as in example 4, except that the pump flow rate was adjusted so that the flow rate in the flow channel FC of the gas release mechanism 30 became 0.3[ m/sec ].

Comparative example 7

As shown in table 2, fine bubbles of air were generated in pure water in the same manner as in example 4, except that the pump flow rate was adjusted so that the flow rate in the flow channel FC of the gas release mechanism 30 became 0.1[ m/sec ].

The produced water obtained in examples 1 to 19 and comparative examples 1 to 7 was left to stand for 15 minutes, and then gently stirred with a stirring rod, and the mode diameter, D90, D50, D10, and the number of bubbles contained in the produced water were measured 5 times using a nanoparticle analysis system (NanoSight LM10, malvern instruments ltd), and the average values thereof are shown in table 1.

[ Table 1]

From Table 1, it was confirmed that the gas releasing member 32 having a pore diameter (mode diameter) of 1.5 μm or less and a small variation in pore diameter distribution ((D90-D10)/D50 ≦ 3) was used so that the flow rate in the flow channel FC of the gas releasing mechanism 30 was 1[ m/sec ]]In the produced water obtained in examples 1 to 10 in which the pump flow rate was adjusted in the above manner, the bubble diameter (mode diameter) was about 100nm, and the fine bubbles having a small distribution irregularity of bubble diameters ((D90-D10)/D50 ≦ 3) were 10 to 10⁸Orders of magnitude of individuals are produced in large quantities.

It was also found that the pores using the gas release pores had a diameter (mode diameter) of 1.5 μm or less and had a large variation in pore size distribution ((D90-D10)/D50)>3) A gas release member 32 for setting the flow velocity in the flow passage FC of the gas release mechanism 30 to 1[ m/sec ]]In examples 11 to 19 in which the pump flow rate was adjusted in the above manner, the bubble diameter (mode diameter) was about 100nm to 170nm, and the bubble diameter distribution had large unevenness ((D90-D10)/D50)>3) The micro-bubbles are 10⁵～10⁸The number of the micro-bubbles generated was larger than that of examples 1 to 10, and the generated micro-bubbles had a larger diameter (mode diameter) and a larger variation in the diameter distribution of the bubbles, and the number of the generated micro-bubbles was small.

On the other hand, it was confirmed that in comparative examples 1 to 3 using the gas release member 32 having the hole diameter (mode diameter) of the gas release hole exceeding 1.5 μm, even if the flow velocity in the flow channel FC of the gas release mechanism 30 is significantly higher than 1[ m/sec ]]5[ m/sec ]]The microbubbles that can be generated have a diameter (mode diameter) of about 160nm to 180nm, are relatively large, and are also generated in a number of 10²～10⁴Of the order of magnitude, are very few.

It was also confirmed that the hole diameter (mode diameter) of the gas release hole was 0.4 μm and significantly reduced to 1.5 μm, and the flow rate in the flow channel FC of the gas release mechanism 30 was set to 1[ m/sec ]]In the reduced comparative examples 4 to 7, the generated microbubbles had a bubble diameter (mode diameter) of about 90nm to 180nm, a breadth, and a generation number of 10²～10⁴Of the order of magnitude, are very few.

According to the above results, to get 10⁵It is necessary to generate fine bubbles having a bubble diameter (mode diameter) of about 100nm to 170nm in order of magnitude of more than one, and to adjust the flow rate in the flow channel FC of the gas release mechanism 30 to 1[ m/sec ] by using the gas release member 32 having a gas release hole with an aperture (mode diameter) of 1.5 μm or less]Above, to use 10⁸The number of the cells is on the order of 100nm in diameter (mode diameter), and the cells are generated in large quantities with small unevenness in cell diameter distribution ((D90-D10)/D50 ≦ 3), and further, it is necessary to suppress the pore diameter distribution (D90-D10)/D50 of the gas releasing pores of the gas releasing member 32 used to 3 or less.

In the above-described embodiment, the spiral flow path FC is provided on the gas discharge surface in order to move the liquid along the gas discharge surface (lower surface) of the gas discharge member 32, but the present invention is not limited to this, and for example, as shown in fig. 7(a), a plurality of linear flow paths FC may be provided in which the gas discharge surface is formed in a horizontal or vertical cross section, and as shown in fig. b, 1 flow path FC may be provided in which both end portions are alternately inverted on the gas discharge surface.

In the above-described embodiment, the gas releasing member 32 having a disk shape is used, but the present invention is not limited thereto, and a cylindrical gas releasing member 32A may be used as shown in fig. 8, for example. In the case of using such a cylindrical gas discharge member 32A, as shown in fig. 9(a) and (B), a gas supply chamber for introducing gas into the hollow portion with both ends closed may be formed, and cylindrical flow path forming members 31A and 31B having 1 spiral groove (see fig. a) formed in the inner peripheral surface or a plurality of linear grooves (see fig. B) extending in the axial direction may be attached in a state where the inner peripheral surface thereof is in contact with the outer peripheral surface of the cylindrical gas discharge member 32A, and a cylindrical body FC for a liquid may be formed by the spiral groove or the linear groove and the outer peripheral surface of the gas discharge member 32A, or conversely, as shown in fig. 10, the hollow portion of the cylindrical gas discharge member 32B may be used as a flow path for a liquid, and the outer peripheral portion of the gas discharge member 32B may be covered with a cylindrical body 37 shown by a two-dot chain line in the figure, thus, a gas supply chamber GR into which gas is introduced is formed on the outer peripheral surface side of the gas release member 32B.

In each of the above embodiments, the flow path forming members 31, 31A, 31B are attached to the lower surface of the disk-shaped gas discharge member 32 or the outer peripheral surface of the cylindrical gas discharge member 32A to form the flow path FC for the liquid, or the hollow part of the cylindrical gas releasing member 32B is used as a flow path of the liquid, however, for example, as shown in FIG. 11, by arranging the gas release member 32C having an outer surface serving as a gas release surface in the liquid flow, the liquid is moved along the outer surface (gas discharge surface) of the gas discharge part 32C, or as shown in fig. 12, in a state where the gas release member 32D having a cylindrical or cylindrical shape with an outer peripheral surface serving as a gas release surface is immersed in a stationary liquid, the liquid is relatively moved along the outer peripheral surface (gas discharge surface) of the gas discharge member 32D by rotating the liquid at a fixed position around the axis.

Further, in each of the above embodiments, the gas release mechanism 30 is disposed on the suction side of the liquid-sending pump 23, but the present invention is not limited to this, and the gas release mechanism 30 may be disposed on the discharge side of the liquid-sending pump 23, as in the fine bubble generating device 2 shown in fig. 13, for example. However, in this case, when the liquid feeding pump 23 is operated, the inside of the flow path FC of the gas release mechanism 30 becomes a positive pressure, and therefore, it is necessary to connect the pipe joint 36 of the gas release mechanism 30 to the air feed pipe 38, provide the air feed pump 39 in the air feed pipe 38, and press out the gas from the gas release surface of the gas release member 32 to the liquid flowing in the flow path FC by the discharge pressure of the air feed pump 39.

In each of the above embodiments, the liquid in the reservoir 10 is sent out to the reservoir 40 through the flow path FC of the gas release mechanism 30, but the present invention is not limited to this, and the liquid in the reservoir 10 may be returned to the reservoir 10 through the flow path FC of the gas release mechanism 30, as in the fine bubble generating device 3 shown in fig. 14, for example.

Industrial applicability of the invention

The method and apparatus for generating fine bubbles according to the present invention can efficiently generate various gases as nano-sized fine bubbles in various liquids, and therefore, by appropriately selecting the liquid and the gas existing as the fine bubbles in the liquid, the method and apparatus can be used in various fields such as treatment of factory waste liquid, cleaning, sterilization, disinfection, preservation of freshness of fresh products, and cultivation of seafood.

Description of reference numerals

1.2, 3 micro-bubble generating device

10. 40 liquid storage tank

20 liquid feeding mechanism (relative moving unit/device)

21. 22 liquid delivery pipe

23 liquid feeding pump

24 valve

30 gas releasing mechanism (component)

31 base member (flow path forming member)

31A, 31B flow passage forming member

31a bottom surface of the recess

31b groove

31c screw hole

31d pipe joint

31e flow path

32. 32A, 32B, 32C, 32D gas releasing member

33 liner

34 cover

34a screw hole

35. 36 piping joint

37 Yen cylinder

38 air supply pipe

39 air pump

FC flow path

GR air supply chamber.