JPWO2019189812A1 - Fine bubble generating nozzle, method for mixing bubbles containing fine bubbles in liquid using the fine bubble generating nozzle, bioreactor equipped with the fine bubble generating nozzle, and a plurality of fine bubble generating nozzles A nozzle device for generating fine bubbles - Google Patents

Abstract

An object of the present invention is to provide a nozzle for generating fine bubbles having a simple shape and structure, which can improve the generation efficiency of fine bubbles and efficiently and sufficiently increase the fine bubble content rate of a liquid. Providing a method for mixing bubbles containing fine bubbles in a liquid using a generating nozzle, providing a bioreactor equipped with the fine bubble generating nozzle, and providing a plurality of the fine bubble generating nozzles Another object is to provide a nozzle device for generating fine bubbles. In order to solve the above problems, the fine bubble generating nozzle of the present invention, the liquid flowing through the nozzle body, along a surface perpendicular to the central axis of the nozzle body, through a slit continuously provided on the side surface, gas By supplying, the generation efficiency of fine bubbles can be improved, and the content ratio of fine bubbles in the liquid can be efficiently and sufficiently increased.

Description

  The present invention relates to a fine bubble generation nozzle used for mixing a liquid with bubbles containing fine bubbles of nano bubbles or micro bubbles of gas such as air and oxygen, to obtain a liquid containing fine bubbles of gas. Method for mixing bubbles containing fine bubbles in a liquid using the bubble generating nozzle, bioreactor equipped with the fine bubble generating nozzle, and fine bubble generating nozzle device equipped with a plurality of the fine bubble generating nozzles Regarding

  Focusing on the action of increasing the dissolved oxygen concentration (DO) of the liquid by the fine air bubbles contained in the liquid, the sterilization / sterilization action, etc., the liquid containing the fine air bubbles is shower water, bath water, washing water, washing water. The field of wastewater treatment such as wastewater generated from various industries such as food plants, pulp plants, and chemical plants, domestic wastewater from households, biological reactions [microorganisms or cells (hereinafter also referred to as "microorganisms", etc. It is used in the field of aquaculture of fish and seafood, and the reaction of producing a reaction product in microorganisms, etc.

  In the present invention, bubbles having a number average diameter of 1 μm or more and 100 μm or less are called microbubbles, and bubbles having a number average diameter of less than 1 μm are called nanobubbles. As a method for measuring the bubble diameter of the fine bubbles, an image analysis method, a laser diffraction scattering method, an electrical detection zone method, a resonance mass measurement method, an optical fiber probe method, etc. are generally used, and a method for measuring the bubble diameter of the nanobubbles is used. As the method, a dynamic light scattering method, a Brownian motion tracking method, an electric detection zone method, a resonance type mass measuring method and the like are generally used. "Nano bubbles", which are extremely small bubbles, are also called "ultra fine bubbles". In addition, at present, ISO (International Organization for Standardization) is considering the creation of an international standard related to fine bubble technology. If an international standard is created, the commonly used name “nano bubble” will be used. There is a possibility that it will be unified into "Ultra Fine Bubble".

  The liquid containing such fine gas bubbles is a plurality of jet nozzles provided on the side surface along the surface perpendicular to the central axis of the nozzle body, with respect to the liquid flowing in the nozzle body made of a cylindrical body. A gas containing fine gas bubbles is obtained by injecting gas from. (Patent Documents 1 and 2)

  For example, Patent Document 1 discloses an aeration device 10 for mud, the appearance of which is schematically shown in FIG. 9. In the aeration device 10, an inlet 12 of a nozzle body 11 made of a tubular body is disclosed. The mud is made to flow into the mud from the discharge port 13 and compressed air is blown from a plurality of air outlets 14 provided on the side surface along the surface perpendicular to the central axis of the nozzle body 11 to generate fine bubbles in the mud. It's mixed. In this aeration device 10, as shown in the schematic diagrams of FIGS. 10 and 11, the compressed air blown into the mud flowing in the nozzle body 11 forms a plurality of gas bands A ′, and It flows along the inner surface and becomes fine bubbles B ′ near the discharge port 13.

  However, in the fine bubble generating nozzle in which gas is blown from a plurality of ejection ports provided on the side surface along the surface perpendicular to the central axis of the nozzle body as disclosed in Patent Documents 1 and 2, the nozzle body is Since the gas blown into the liquid flowing inside forms a plurality of strips and flows along the inner surface of the nozzle body, the generation efficiency of fine bubbles is poor and the content ratio of fine bubbles in the liquid can be efficiently and sufficiently increased. Is difficult

  Patent Document 3 discloses a nozzle in which ozone is blown from a jet annular opening toward a high-speed water jet at an opening and is made to flow into the water jet by the action of a circulating vortex. Further, Patent Document 4 discloses a loop-type bubble generating nozzle that agitates and mixes a pressurized liquid and a gas supplied from an annular gap by a loop flow in an agitating / mixing chamber.

  However, the nozzles disclosed in Patent Documents 3 and 4 described above mix liquid and gas by generating a turbulent flow at a specific location such as an opening or a stirring / mixing chamber. Nozzle, such as the nozzles disclosed in the above-mentioned Patent Documents 1 and 2, blows a gas to a liquid flowing in the nozzle body and flows along the inner surface of the nozzle body, generating fine bubbles having a simple shape and structure. It is not a nozzle.

JP-A-2004-121988 JP, 2006-034235, A Japanese Patent No. 3686763 Japanese Patent No. 5002480

  The inventors of the present invention use a fine bubble generating nozzle having a nozzle body having a simple shape and structure made of a tubular body, improve the generation efficiency of fine bubbles, and efficiently and sufficiently increase the fine bubble content rate of liquid. The inventors of the present invention have made the present invention through extensive experiments and studies.

  That is, an object of the present invention is to provide a fine bubble generation nozzle having a simple shape and structure, which can improve the generation efficiency of fine bubbles and efficiently and sufficiently increase the fine bubble content rate of a liquid. To provide a method for mixing bubbles containing fine bubbles into a liquid using the fine bubble generating nozzle, to provide a bioreactor equipped with the fine bubble generating nozzle, and to provide a plurality of the fine bubble generating nozzles. An object of the present invention is to provide a nozzle device for generating fine bubbles, which is provided with the present invention.

  The inventors of the present invention generate a fine bubble by generating a fine bubble generating nozzle having a conventional simple shape and structure (that is, flowing a gas blown into a liquid flowing in the nozzle body along an inner surface of the nozzle body). In a conventional nozzle), surprisingly, by supplying gas to the liquid flowing through the nozzle body, along a surface perpendicular to the central axis of the nozzle body, through a slit provided continuously on the side surface. The inventors of the present invention have found that the generation efficiency of fine bubbles can be improved and the content of fine bubbles in a liquid can be efficiently and sufficiently increased.

The gist of the present invention is shown below.
(1) A fine bubble generation nozzle for mixing bubbles containing fine bubbles of nano bubbles or micro bubbles into a liquid to obtain a liquid containing the fine bubbles,
On the upstream side, an inflow port into which the liquid flows is provided, and on the downstream side, a nozzle body formed of a tubular body provided with an ejection port for ejecting the liquid mixed with the bubbles containing the fine bubbles,
Along the surface perpendicular to the central axis of the nozzle body, a slit continuously provided on the side surface,
A nozzle for generating fine bubbles, comprising a gas supply unit connected to the slit and supplying gas to the slit.
(2) The fine bubble generating nozzle according to (1), wherein the slit has an acute angle θ that is inclined upstream with respect to a plane perpendicular to the central axis of the nozzle body.
(3) The nozzle for generating fine bubbles according to (1) or (2), wherein the slit is provided in a plurality of stages on the nozzle body.
(4) The nozzle body is formed of one tubular body, and the slit is provided by cutting the peripheral surface of the one tubular body, leaving a connection part in part. The nozzle for generating fine bubbles according to any one of (1) to (3).
(5) The nozzle body is formed of two or more tubular bodies, and the slit is formed in a connecting portion of the tubular bodies. (1) to (3) The nozzle for generating fine bubbles according to any one of claims.
(6) The fine bubble generating nozzle according to any one of (1) to (5), wherein the inner diameter of the nozzle body near the discharge port is gradually expanded toward the downstream side.
(7) The fine bubble generating nozzle according to any one of (1) to (6), wherein the fine bubble generating nozzle is used for a chemical reaction.
(8) The fine bubble generating nozzle according to any one of (1) to (6), wherein the fine bubble generating nozzle is used for a biological reaction.
(9) A method of mixing bubbles containing fine bubbles of nano bubbles or micro bubbles into a liquid using the fine bubble generating nozzle according to any one of (1) to (8).
(10) A culture tank containing a culture solution and a biological culture solution containing an aerobic or facultative anaerobic microorganism, and a biological culture solution extracted from the culture tank contains bubbles containing fine bubbles of nanobubbles or microbubbles A bioreactor, comprising: the microbubble-generating nozzle according to (8); and a pipe line that recirculates the bioculture liquid containing the microbubbles into the culture tank.
(11) The amount of the biological culture solution that is withdrawn from the culture tank and contains bubbles containing fine bubbles of nanobubbles or microbubbles and then is returned to the culture tank per minute, and the amount of the biological culture solution stored in the culture tank is The bioreactor according to (10), which is set to 1% or more and less than 48% of the amount of the liquid.
(12) A plurality of the fine bubble generating nozzles according to any one of (1) to (8) are provided in parallel, and in each fine bubble generating nozzle, the fine bubbles of nano bubbles or micro bubbles are parallel to the liquid. A nozzle device for generating fine bubbles, comprising mixing bubbles containing bubbles to obtain a liquid containing the fine bubbles.

  The nozzle for generating fine bubbles of the present invention has a simple shape and structure, can improve the generation efficiency of fine bubbles, and can efficiently and sufficiently increase the content rate of fine bubbles in a liquid.

  Further, the method of mixing bubbles containing fine bubbles in a liquid using the nozzle for generating fine bubbles of the present invention is a simple and economical method for efficiently and sufficiently increasing the fine bubble content rate to form fine bubbles in a liquid. Bubbles containing can be mixed.

  Further, the bioreactor equipped with the nozzle for generating fine bubbles of the present invention can efficiently and sufficiently increase the fine bubble content rate to mix the bubbles containing fine bubbles in the liquid simply and economically. By providing the nozzle for generating fine bubbles, the stress and damage to the microorganisms and the like can be reduced, and the biological reaction can be performed efficiently and economically.

  Further, a fine bubble generating nozzle device provided with a plurality of the fine bubble generating nozzles of the present invention, by forming a fine bubble generating nozzle device by providing a plurality of fine bubble generating nozzles in parallel, A liquid containing bubbles can be generated more efficiently.

It is a schematic diagram which shows the external appearance of 1st Embodiment of the nozzle for micro air bubble generation of this invention. It is a schematic diagram which shows the cross section of 1st Embodiment of the nozzle for fine bubble generation of this invention. It is a schematic diagram which shows the II cross section in FIG. It is a schematic diagram which shows the external appearance of the nozzle for fine bubble generation of FIG. 1 which provided the gas supply part. It is a schematic diagram which shows the cross section of 2nd Embodiment of the nozzle for micro air bubble generation of this invention. It is a schematic diagram which shows the cross section of 3rd Embodiment of the nozzle for fine bubble generation of this invention. It is a schematic diagram which shows the cross section of 4th Embodiment of the nozzle for fine air bubble generation of this invention. It is a schematic diagram of a culture device for microorganisms and the like showing an application example of the nozzle for generating fine bubbles of the present invention. It is a schematic diagram which shows the external appearance of the nozzle for fine bubble generation of patent document 1. It is a schematic diagram which shows the cross section of the nozzle for fine bubble generation of patent document 1. It is a schematic diagram which shows the II-II cross section in FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not limited thereto.

<General fine bubble generation nozzle>
First, the nozzle of the present invention, such as the nozzles disclosed in Patent Documents 1 and 2 above, has a simple shape of a type in which a gas is blown into a liquid flowing in the nozzle body and flows along the inner surface of the nozzle body. A fine bubble generating nozzle having a structure will be described.

  As shown in FIGS. 1 to 3 (present invention) and FIGS. 9 to 11 (conventional example), the fine bubble generating nozzle having the simple shape and structure is supplied from the inflow ports 2 and 12, and the nozzle main bodies 1 and 11 are supplied. With respect to the liquid flowing inside, along the surface perpendicular to the central axis of the nozzle bodies 1 and 11, the slit 4 provided continuously on the side surface, and on the side surface along the surface perpendicular to the central axis. A gas is blown from a supply port such as the air jet port 14, and the blown gas flows along the inner surfaces of the nozzle bodies 1 and 11, fine bubbles B and B ′ are gradually formed, and near the discharge ports 3 and 13. To form a large amount of fine bubbles B and B '.

<Characteristics of the nozzle for generating fine bubbles of the present invention>
In the conventional nozzle for generating fine bubbles as shown in FIGS. 9 to 11, the nozzles provided on the side surface along the surface perpendicular to the central axis of the nozzle body 11 with respect to the liquid flowing in the nozzle body 11 made of a tubular body. The gas blown from the plurality of air jets 14 thus formed forms a plurality of gas bands A ′ and flows along the inner surface of the nozzle body 11 into fine bubbles B ′ in the vicinity of the discharge port 13. The production efficiency of is small, and it is difficult to efficiently and sufficiently increase the content of fine bubbles in the liquid.

  On the other hand, in the fine bubble generating nozzle of the present invention as shown in FIGS. 1 to 3 (present invention), a surface perpendicular to the central axis of the nozzle body 1 with respect to the liquid flowing in the nozzle body 1 formed of a tubular body. The gas blown from the slits 4 provided continuously along the side surface along the inner surface of the nozzle body 1 has a wide thin layer A (hereinafter also referred to as “thin layer A”) in which the gas is continuous. Flow along the inner surface of the nozzle body 1 to gradually form the fine bubbles B, and a large amount of the fine bubbles B are formed in the vicinity of the discharge port 3, thus improving the generation efficiency of the fine bubbles, The content of fine bubbles in the liquid can be efficiently and sufficiently increased.

  The tubular body of the nozzle body 1 used in the present invention may have a circular or rectangular cross-sectional shape, but a circular shape is preferable. By making the cross-sectional shape circular, the thickness of the thin layer A can be made uniform, and the content of fine bubbles in the liquid tends to be efficiently increased. The cross-sectional shape of the tubular body of the nozzle body 1 may be a perfect circle as shown in FIG. 3, or may be a substantially perfect circle or an ellipse.

  In the present invention, the slits 4 are “provided along a surface perpendicular to the central axis of the nozzle body 1 (hereinafter, also referred to as“ vertical surface ”)”, but this is provided substantially along the vertical surface. Means to be done. Further, in the present invention, the slit 4 is “continuously provided on the side surface of the nozzle body 1”, but as will be described later, when the nozzle body 1 is formed by one tubular body, the slit 4 is formed. It is also possible to leave a connecting part in a part so that the nozzle main body 1 is not separated by providing.

  In addition, it is preferable to arrange a rod-shaped body, preferably a rod-shaped body having a circular cross-section, along the central axis of the nozzle body 1 formed of a tubular body. Accordingly, even if the amount of liquid supplied to the nozzle body 1 is the same, the flow velocity of the liquid flowing in the nozzle body 1 (hereinafter, also referred to as “liquid flow velocity”) can be increased, so that the thin layer A is stabilized. It is possible to efficiently form a liquid, and it is possible to efficiently generate a liquid containing fine bubbles of nano bubbles or micro bubbles.

In order to smoothly form the thin layer A using the fine bubble generating nozzle of the present invention,
1) the flow velocity of the liquid, and 2) the flow velocity of the gas blown from the slit 4 in a direction orthogonal to the flow of the liquid in the nozzle body 1 (hereinafter, also referred to as “gas flow velocity”).
It is necessary to have an appropriate balance of. When the flow velocity of the gas is too high as compared with the flow velocity of the liquid, the gas is blown into the vicinity of the central axis of the nozzle body 1 and it becomes difficult to form the thin layer A. On the other hand, when the flow velocity of the gas is too low as compared with the flow velocity of the liquid, the liquid leaks from the slit 4 to the outside of the nozzle body 1.

<Gas supply unit>
As shown in FIG. 4, in the fine bubble generating nozzle of the present invention, a gas supply unit 5 for supplying a pressurized gas (for example, pressurized air and / or oxygen) is connected to the slit 4. . Suitably, the gas supply part 5 is airtightly provided outside the nozzle body 1 so as to surround the slit 4.

  The pressure of the gas supplied to the gas supply unit 5 (hereinafter, also referred to as “gas pressure”) is basically set so that the liquid does not leak from the slit 4 to the outside of the nozzle body 1. The pressure is preferably higher than the pressure of the liquid flowing in the nozzle body 1.

  On the other hand, when the pressure of the gas is increased, the flow velocity of the gas is increased accordingly. Therefore, when the pressure of the gas is increased too much, the flow velocity of the gas becomes too large as compared with the flow velocity of the liquid, and it is difficult to form the thin layer A. Tends to be.

  The pressure of the gas can be set to an appropriate value in consideration of these factors, but normally, the lower limit is the pressure (for example, 1.5 atm) at which the liquid does not leak from the slit 4 to the outside of the nozzle body 1. It is preferable that the value is 3.0 atm and the upper limit value is 3.0 atm.

<Slit>
As shown in FIGS. 1-2 and 5-7, the slit 4 of the present invention is a pore continuously provided on the side surface along the surface perpendicular to the central axis of the nozzle body 1.

  The gap between the slits 4 can be set to an appropriate value capable of forming the thin layer A in consideration of the liquid flow rate, the gas flow rate, and the gas pressure.

  Further, if the gap of the slit 4 is too narrow, the generation efficiency of the fine bubbles B decreases, and if it is too wide, it becomes difficult to form the fine bubbles B from the thin layer A in the vicinity of the discharge port 3, so these factors are also taken into consideration. You can set an appropriate value.

  The gap of the slit 4 can be set to an appropriate value in consideration of these factors, but is usually 0.5 mm to 2.0 mm, preferably 0.5 mm to 1.5 mm, more preferably 0.5 mm. It can be set in the range of 0.8 mm.

  In order to efficiently increase the content of fine bubbles in the liquid, it is preferable to increase the flow rate of gas to increase the amount of gas blown, but on the other hand, in the above <Features of the nozzle for generating fine bubbles of the present invention>. As described above, as the gas flow velocity becomes higher than the liquid flow velocity, it becomes difficult to form the thin layer A.

  In order to achieve both the “improvement of the content of fine bubbles in the liquid” and the “stable formation of the thin layer A”, the slit 4 is provided on the upstream side with respect to the plane perpendicular to the central axis of the nozzle body 1. It is preferable to incline. As a result, even if the gas flow velocity itself is increased, the gas flow velocity in the direction orthogonal to the liquid flow in the nozzle body 1 can be reduced, which hinders the formation of the thin layer A. The angle θ (hereinafter, also referred to as “tilt angle θ”) inclined to the upstream side with respect to the plane perpendicular to the central axis of the nozzle body 1 stabilizes the thin layer A according to the flow velocity of the liquid, the flow velocity of the gas, and the like. Can be sharpened so that it can be formed as desired. In consideration of the above effect, the inclination angle θ is preferably 0 ° or more and 80 ° or less, more preferably 60 ° or more and 80 ° or less, and further preferably 70 ° or more and 80 ° or less.

  Further, in order to achieve both the “improvement of the content of fine bubbles in the liquid” and the “stable formation of the thin layer A”, it is also preferable to provide the nozzle body 1 with a plurality of slits 4. As a result, the amount of gas blown in can be increased without increasing the gas flow rate itself. It is preferable that the number of steps of the slit 4 is large from the viewpoint of increasing the amount of gas blown, but if it is too large, the structure of the nozzle becomes complicated and the manufacturing cost and maintenance cost increase, so consider these factors. It can be set appropriately. Generally, the number of steps of the slit 4 is preferably 1 to 3.

<Formation of slits>
As shown in FIG. 1 and FIG. 2 (first embodiment of the nozzle for generating fine bubbles of the present invention), the slit 4 forms the nozzle body 1 with one tubular body 1 a, and a connecting portion is provided in a part thereof. It can be formed by cutting the peripheral surface of the tubular body, and FIG. 5 (second embodiment of the fine bubble generating nozzle of the present invention) and FIG. 6 (fine bubble generating nozzle of the present invention). No. 3) and FIG. 7 (fourth embodiment of the nozzle for generating fine bubbles of the present invention), the nozzle body 1 is formed of two or more tubular bodies 1b, 1c, etc. It can also be formed at the connecting portion of the tubular bodies 1b, 1c and the like.

  In the second embodiment of the nozzle for generating fine bubbles of the present invention shown in FIG. 5, the nozzle body 1 is formed by two tubular bodies 1b and 1c having a circular cross-sectional shape, and these tubular bodies 1b and 1c are formed. Although the slit 4 having the inclination angle θ is formed at the connection portion of the nozzle body 1, in the second embodiment, the cleaning of the slit 4 becomes difficult because the slit 4 having a small cross section becomes long. There is a concern that the pressure of the gas supplied to the device will drop due to the pressure loss.

  The third embodiment of the nozzle for generating fine bubbles of the present invention shown in FIG. 6 eliminates the above-mentioned concern. In the tubular body 1c having a circular cross-sectional shape, the tubular body 1b having a circular cross-sectional shape is used. The length of the slit 4 is shortened by cutting the tip of the connecting portion. Thereby, the cleaning of the slit 4 can be facilitated and the pressure loss of the gas supplied into the nozzle body 1 can be reduced.

<Discharge port>
As shown in FIG. 2, in the vicinity of the discharge port 3, the thin layer A separates from the inner surface of the nozzle body 1 to form fine bubbles B, but in order to facilitate the separation of the thin layer A from the inner surface of the nozzle body 1, The inner diameter of the nozzle body 1 near the discharge port 3 can be gradually expanded toward the downstream side.

  Further, as in the fourth embodiment of the nozzle for generating fine bubbles of the present invention shown in FIG. 7, unevenness is formed on the inner surface of the nozzle body 1 in the vicinity of the discharge port 3 to cause turbulent flow in the liquid flow. The formation of the fine bubbles B can be promoted. As means for forming irregularities on the inner surface of the nozzle body 1, means for cutting the inner surface of the nozzle body 1 to form concave portions, means for joining a coiled member to the inner surface of the nozzle body 1 to form convex portions, and the like Is mentioned.

<Use of nozzle>
The fine bubble generating nozzle of the present invention can efficiently and sufficiently increase the fine bubble content rate and mix the bubbles containing the fine bubbles into the liquid easily and economically. Utilizing the effect of increasing concentration (DO), sterilization and sterilization,
〇 Manufacture and supply of shower water, bathtub water, washing water, cleaning water, etc.
-Wastewater generated from various industries such as food plants, pulp plants, and chemical plants, wastewater treatment such as household wastewater,
-Aquaculture of fish and shellfish-It can be used in a wide range of fields such as chemical reactions and biological reactions.

  In particular, the nozzle for generating fine bubbles of the present invention can be suitably used in a chemical reaction using a reaction liquid in which a solid catalyst is dispersed as a liquid, and a biological reaction using a culture liquid containing a microorganism as a liquid.

  That is, the solid catalyst used in the chemical reaction is fragile, and the activity of the microorganisms used in the biological reaction decreases due to stress and damage. However, in the fine bubble generating nozzle of the present invention, the thin layer A is the solid catalyst. Since it plays the role of a cushion that prevents the microorganisms and the like from colliding with the inner surface of the nozzle body 1, it is possible to reduce the damage to the solid catalyst and the stress and damage to the microorganisms and the like. Further, in the microbubble generating nozzle of the present invention, the microbubble content can be efficiently and sufficiently increased even if the flow velocity of the liquid is reduced, so that the solid catalyst is not broken, and the microorganisms are not stressed or damaged. can do.

<Bioreactor>
Among them, the nozzle for generating fine bubbles of the present invention cultivates aerobic or facultative anaerobic microorganisms (hereinafter, also referred to as “microorganisms and the like”) to generate reaction products in the microorganisms and the like. It can be used particularly preferably in a bioreactor for growing a.

In the bioreactor shown in FIG.
1) a step of withdrawing a biological culture solution 6 containing a culture solution and microorganisms from a culture tank 7,
2) A step of supplying the extracted biological culture solution 6 to the micro / nano bubble generation tank 8 to cause the micro / nano bubble generation device 9 to contain fine bubbles, and 3) a reflux conduit for the biological culture solution 6 containing the fine bubbles. A biological reaction is carried out in the step of returning to the culture tank 7 through the above. By using the nozzle for generating fine bubbles of the present invention as the "micro / nano bubble generator 9", as shown in FIG. Plays a role of a cushion for preventing the collision of the inner surface of the nozzle body 1 with the inner surface of the nozzle body 1 and can reduce stress and damage received by microorganisms and the like.

  Further, as the "micro / nano bubble generator 9", by using the fine bubble generating nozzle of the present invention capable of efficiently producing a liquid having a high fine bubble content, the fine bubble generating nozzle 9 is extracted from the culture tank 7, and after culturing after containing fine bubbles. Since the amount of the biological culture solution 6 refluxed to the tank 7 can be set to be as low as 1% or more and less than 48% of the amount of the biological culture solution 6 stored in the culture tank 7 per minute, microorganisms can be circulated by liquid circulation. It is possible to reduce the stress and damage received by the etc.

<Method of mixing bubbles containing fine bubbles in liquid>
The method of mixing bubbles containing fine bubbles in the liquid of the present invention can be carried out by using the above-mentioned fine bubble generating nozzle, and simply and economically efficiently and sufficiently increase the fine bubble content rate, It is possible to mix bubbles containing fine bubbles.

<Nozzle device for generating fine bubbles>
The fine bubble generating nozzle of the present invention can efficiently generate a liquid having a high fine bubble content rate, and a plurality of fine bubble generating nozzles are provided in parallel to form a fine bubble generating nozzle device. This makes it possible to more efficiently generate the liquid containing the fine bubbles.

  This fine bubble generating nozzle device collects the liquid containing fine bubbles from the liquid supply unit that distributes and supplies the liquid to the inlet of each fine bubble generating nozzle, and the discharge port of each fine bubble generating nozzle. A fine air bubble-containing liquid recovery unit is provided for recovery.

  Next, the fine bubble generating nozzle of the present invention will be described using Examples and Comparative Examples, but the present invention is not limited to these Experimental Examples and Comparative Experimental Examples.

<Examples 1-2 and Comparative Examples 1-2>
In Examples 1 and 2 and Comparative Examples 1 and 2 below, as summarized in Table 1, nozzles for generating fine bubbles having the following shapes and structures were used.
〇 Nozzle body: Cylindrical body with an inner diameter of 6.0 mm and circular cross section 〇 Slits or holes provided in the nozzle body:
[Example 1] An angle θ inclined to the upstream side with respect to a surface perpendicular to the central axis of the nozzle body, which is continuously provided on the side surface along a surface perpendicular to the central axis of the nozzle body, is 0 °, Slits with a gap of 0.8 mm [Example 2] Along the surface perpendicular to the central axis of the nozzle body, which was continuously provided on the side surface, the upstream side of the surface perpendicular to the central axis of the nozzle body. Slits having an inclined angle θ of 75 ° and a gap of 0.8 mm [Comparative Example 1] Centers of the nozzle body, which are continuously provided on the side surface at equal intervals along a plane perpendicular to the central axis of the nozzle body. Angle θ inclined to the upstream side with respect to the plane perpendicular to the axis is 0 °, and three holes having a diameter of 1.0 mm [Comparative Example 2] Along the plane perpendicular to the central axis of the nozzle main body Angle θ that is inclined at the upstream side with respect to the plane perpendicular to the central axis of the nozzle body, which is provided at equal intervals, is 0 °, 3 holes with a diameter of 2.0 mm 〇 Number of slits or holes: 1 step

  An aqueous solution of glucose having a concentration of 10% by mass (hereinafter, referred to as “dextrose aqueous solution”) was flown into the nozzles for generating fine bubbles of Examples 1 and 2 and Comparative Examples 1 and 2 from the inlet at one end of the nozzle body. While supplying 16 m / sec, air was supplied from a slit or a hole provided in the nozzle body at an air flow rate of 30 L / min to prepare an aqueous glucose solution in which fine air bubbles were mixed.

  The KLA [mass transfer capacity coefficient (/ h)] of the obtained glucose aqueous solution mixed with fine air bubbles was measured. The results are shown in Table 2.

KLA [mass transfer capacity coefficient (/ h)] is generally used as an index representing the dissolved oxygen concentration (DO) of a liquid, and the larger this value, the higher the dissolved oxygen concentration of the liquid. There is. That is, in order for oxygen in the air to be dissolved in the liquid to become dissolved oxygen, the gas phase oxygen molecule O ₂ must move into the liquid. This oxygen transfer rate OTR is represented by the following general formula (1). Therefore, the larger the value of KLA, the higher the dissolved oxygen concentration of the liquid.
_{OTR = KLA × (C S -C} ) ··· (1)
In this equation (1),
OTR: Oxygen transfer rate (mg / L · h)
KLA: Mass transfer capacity coefficient (/ h)
C _S : Saturation solubility of oxygen in water (mg / L)
C: Solubility of oxygen in water (mg / L).

  From the comparison between Examples 1 and 2 (the shape of the air supply port is “slit”) and Comparative Examples 1 and 2 (the shape of the air supply port is “hole”), the shape of the air supply port provided in the nozzle body is “slit”. It can be seen that, by setting "," the concentration of dissolved oxygen in the liquid can be significantly increased as compared with the case of forming "pores" (Comparative Examples 1 and 2).

  Further, comparing Example 1 (angle θ is 0 °) and Example 2 (angle θ is 75 °), by inclining the slit to the upstream side with respect to the plane perpendicular to the central axis of the nozzle body, It can be seen that the concentration of dissolved oxygen in the liquid can be increased.

  In addition, in the dextrose aqueous solution in which the fine air bubbles of the air obtained in Example 2 (the shape of the air supply port is “slit”) and Comparative Example 1 (the shape of the air supply port is “hole”) are mixed, The bubble size distribution of bubbles was measured using an image analysis particle size measuring device (manufactured by Microtrac Bell). The bubble size distribution of Example 2 is shown in Table 3, and the bubble size distribution of Comparative Example 1 is shown in Table 4.

  The bubble distributions shown in Tables 3 and 4 were measured for 1 minute using the above-described measuring device, the horizontal axis represents the particle size (μm) of the bubbles, and the vertical axis represents each bubble diameter with respect to the total number of measured bubbles. The percentage (%) of air bubbles is shown.

  Air bubble size distribution of fine air bubbles in Example 2 (air supply port shape is "slit") and fine air bubble bubbles in Comparative Example 1 (air supply port shape is "hole") From the comparison with the diameter distribution (Table 4), by making the shape of the air supply port provided in the nozzle body a "slit", the bubble diameter of the fine air bubbles can be made smaller and the bubble diameter can be made smaller than when it is a "hole". It can be seen that the distribution of can be sharpened.

1 Nozzle main body 1a Cylindrical body 1b Cylindrical body 1c Cylindrical body 2 Inlet port 3 Discharge port 4 Slit 5 Gas supply part 6 Biological culture liquid 7 Culture tank 8 Micro / nano bubble generating tank 9 Micro / nano bubble generating device 10 Aeration device 11 Nozzle main body 12 Inlet 13 Discharge Port 14 Air Jet A A wide continuous thin layer of gas (formed along the inner surface of the nozzle body) A ′ (formed along the inner surface of the nozzle body) multiple bands of gas B Micro Bubble B'Micro Bubble

The gist of the present invention is shown below.
(1) A fine bubble generation nozzle for mixing bubbles containing fine bubbles of nano bubbles or micro bubbles into a liquid to obtain a liquid containing the fine bubbles,
On the upstream side, an inflow port into which the liquid flows is provided, and on the downstream side, a nozzle body formed of a tubular body provided with an ejection port for ejecting the liquid mixed with the bubbles containing the fine bubbles,
Along the surface perpendicular to the central axis of the nozzle body, a slit continuously provided on the side surface,
Connected to said slit, have a gas supply unit for supplying gas to said slit,
The nozzle body has a circular cross-sectional shape and has no step on the inner surface ,
A nozzle for generating fine bubbles.
(2) The fine bubble generating nozzle according to (1), wherein the slit has an acute angle θ that is inclined upstream with respect to a plane perpendicular to the central axis of the nozzle body.
(3) The nozzle for generating fine bubbles according to (1) or (2), wherein the slit is provided in a plurality of stages on the nozzle body.
(4) The nozzle body is formed of one tubular body, and the slit is provided by cutting the peripheral surface of the one tubular body, leaving a connection part in part. The nozzle for generating fine bubbles according to any one of (1) to (3).
(5) The nozzle body is formed of two or more tubular bodies, and the slit is formed in a connecting portion of the tubular bodies. (1) to (3) The nozzle for generating fine bubbles according to any one of claims.
(6) The fine bubble generating nozzle according to any one of (1) to (5), wherein the inner diameter of the nozzle body near the discharge port is gradually expanded toward the downstream side.
(7) The fine bubble generating nozzle according to any one of (1) to (6), wherein the fine bubble generating nozzle is used for a chemical reaction.
(8) The fine bubble generating nozzle according to any one of (1) to (6), wherein the fine bubble generating nozzle is used for a biological reaction.
(9) A method of mixing bubbles containing fine bubbles of nano bubbles or micro bubbles into a liquid using the fine bubble generating nozzle according to any one of (1) to (8).
(10) A culture tank containing a culture solution and a biological culture solution containing an aerobic or facultative anaerobic microorganism, and a biological culture solution extracted from the culture tank contains bubbles containing fine bubbles of nanobubbles or microbubbles A bioreactor, comprising: the microbubble-generating nozzle according to (8); and a pipe line that recirculates the bioculture liquid containing the microbubbles into the culture tank.
(11) The amount of the biological culture solution that is withdrawn from the culture tank and contains air bubbles containing fine bubbles of nanobubbles or microbubbles and then is returned to the culture tank per minute, and the amount of the biological culture solution is stored in the culture tank. The bioreactor according to (10), which is set to 1% or more and less than 48% of the amount of the liquid.
(12) A plurality of the fine bubble generating nozzles according to any one of (1) to (8) are provided in parallel, and in each fine bubble generating nozzle, the fine bubbles of nano bubbles or micro bubbles are parallel to the liquid. A nozzle device for generating fine bubbles, comprising mixing bubbles containing bubbles to obtain a liquid containing the fine bubbles.

Claims (12)

A fine bubble generating nozzle for mixing a liquid with bubbles containing fine bubbles of nanobubbles or microbubbles to obtain a liquid containing the fine bubbles,
On the upstream side, an inflow port into which the liquid flows is provided, and on the downstream side, a nozzle body formed of a tubular body provided with an ejection port for ejecting the liquid mixed with the bubbles containing the fine bubbles,
Along the surface perpendicular to the central axis of the nozzle body, a slit continuously provided on the side surface,
A nozzle for generating fine bubbles, comprising a gas supply unit connected to the slit and supplying gas to the slit.   The fine bubble generating nozzle according to claim 1, wherein the slit has an acute angle θ with which the slit is inclined upstream with respect to a plane perpendicular to the central axis of the nozzle body.   The fine bubble generating nozzle according to claim 1 or 2, wherein the slits are provided in a plurality of stages on the nozzle body.   The nozzle main body is formed of one tubular body, the slit is provided by cutting the peripheral surface of the one tubular body, leaving a connection portion in part. The nozzle for generating fine bubbles according to claim 1.   4. The nozzle body according to claim 1, wherein the nozzle body is formed of two or more tubular bodies, and the slit is formed in a connecting portion of the tubular bodies. A nozzle for generating fine bubbles.   The fine bubble generating nozzle according to any one of claims 1 to 5, wherein an inner diameter of the nozzle body near the discharge port is gradually expanded toward the downstream side.   The fine bubble generating nozzle according to claim 1, wherein the fine bubble generating nozzle is used for a chemical reaction.   The fine bubble generating nozzle according to any one of claims 1 to 6, wherein the fine bubble generating nozzle is used for a biological reaction.   A method for mixing bubbles containing fine bubbles of nanobubbles or microbubbles with a liquid using the fine bubble generating nozzle according to any one of claims 1 to 8. A culture tank containing a culture solution and a biological culture solution containing an aerobic or facultative anaerobic microorganism, and
The microbubble-generating nozzle according to claim 8, wherein the biological culture liquid extracted from the culture tank contains bubbles containing fine bubbles of nanobubbles or microbubbles.
A conduit for returning the biological culture solution containing the fine bubbles to the culture tank;
A bioreactor comprising:   The amount of the biological culture solution that is withdrawn from the culture tank and contains the bubbles containing fine bubbles of nanobubbles or microbubbles and then is returned to the culture tank is the amount of the biological culture solution stored in the culture tank per minute. The bioreactor according to claim 10, which is set to 1% or more and less than 48%.   A plurality of nozzles for generating fine bubbles according to any one of claims 1 to 8 are provided in parallel, and in each of the nozzles for generating fine bubbles, liquid containing fine bubbles of nano bubbles or micro bubbles is parallel to the liquid. A fine bubble generating nozzle device, characterized in that a liquid containing the fine bubbles is mixed.

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