JP2001259395A - Aerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aerator for continuously feeding a large amount of foams of uniform foam size of approximately several tens μm into a treatment liquid by a small amount of consumption energy. SOLUTION: The aerator is provided with a jet flow forming tank 3 with a jet outlet 4 opened on its bottom 3a to be immersed in the liquid 1 to be treated, the liquid feed means 7 feeding a liquid W into the jet flow forming tank 3 in the jet direction of forming swirl flows swirling inside the tank along the peripheral wall of the jet flow forming tank 3 and a gas feed means 9 naturally sucking air G by swirl flows from a gas introduction inlet 8a provided facing a jet outlet 4 in the jet flow forming tank 3 and feeding the air into the just flow forming tank 3, and the liquid W is fed into the jet flow forming tank 3 to form gas and liquid two phase flows in the jet flow forming tank 3, and the gas and liquid two phase flows are dispersed and jetted from the jet outlet 4 into the liquid 1 to be treated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aerator for generating fine bubbles in a liquid.

[0002]

2. Description of the Related Art As a method for purifying water from rivers, lakes and marshes, and purifying sewage such as domestic wastewater, there is known a method utilizing the biological oxidizing action of aerobic microorganisms in a liquid to be treated. Also, in the purification treatment by such a method, it is also known that it is effective to introduce fine air bubbles into the liquid to be treated in order to activate the biological oxidizing action of aerobic microorganisms.

[0003] Various types of bubble generators have been developed for such purification treatment. For example, in a method using a diffuser, the introduced gas is supplied as bubbles in the liquid through the pores. Further, in the mechanical method, the gas introduced by the rotating wings is fragmented to generate bubbles.

In the method using a diffuser, there is a variation in bubble size due to blockage of pores, a reduction in bubble generation rate, and a limit on the amount of bubble generation. In addition, because the stirring action is insufficient,
Although effective for a limited volume of processing solution, it has the drawback that it is impossible to process a large volume of solution for rivers and lakes. Further, the mechanical method has disadvantages in that the energy consumption is large and the variation in bubble size is large.

[0005] In a conventional bubble generator (hereinafter referred to as an aerator), for example, in the case of using a tube having pores arranged in a liquid tank to be treated, the bubble generator generates bubbles. There are problems that the bubble size varies and the bubble generation rate decreases, and that the amount of bubble generation is limited. In addition, there is a possibility that such blockage of the pores may occur in a relatively short time, and there is also a problem that maintenance of the aerator requires a large amount of labor.

In order to increase the degree of contribution to liquid purification, it is necessary that the generated bubbles and the liquid to be treated are well mixed. That is, it is preferable that the liquid containing gas bubbles (gas-liquid mixed two-phase flow) discharged from the aerator is vigorously discharged into the liquid to be treated, and that the contact between the liquid to be treated and the bubbles is promoted.

Therefore, the present inventors have studied the above problems and have developed an aerator described in Japanese Patent Application Laid-Open No. 10-230150. With this aerator, it has become possible to increase the generation efficiency of bubbles in the liquid to be treated, and to increase the contact efficiency between the bubbles generated by the stirring action of the discharge flow and the liquid to be treated.

[0008]

As a result of a study conducted by the inventors of the present application, it was found that the bubble size was small between the bubble size of the bubbles supplied into the liquid to be treated by the gas-liquid mixed flow and the actual purification performance. It was recognized that the purification performance was improved as the size became uniform. In particular, when a large number of fine and uniform bubbles of about several tens of μm were generated, the purification performance was significantly improved.

That is, even if the total amount of air sent into the liquid is the same, if the bubble size is reduced, the surface area of the bubbles sent out into the liquid increases accordingly, and the contact area with the liquid increases. In addition, the floating time of the bubbles in the liquid becomes longer, and the contact time between the liquid and the bubbles becomes longer. Thereby, the dissolving efficiency of oxygen in the liquid is improved, and the contribution to the activation of the biological oxidizing action by the aerobic microorganisms is increased. Therefore, it is necessary to reduce the bubble size of the bubbles sent into the liquid to be treated for the purification process while reducing the bubble size in order to improve the purification performance.

The present invention has been made in view of such a problem, and it is possible to continuously supply a large amount of bubbles having a uniform size of about several tens μm into a liquid to be treated with a small amount of energy consumption. An object of the present invention is to provide an aerator that can be used.

[0011]

According to a first aspect of the present invention, a gas-liquid two-phase flow formed by taking a gaseous phase into a liquid is discharged into the liquid to be treated. In the aerator that supplies fine bubbles to the liquid to be processed, a discharge port is opened at the bottom and the discharge flow forming tank is immersed in the liquid to be processed, and the inside of the tank is formed along the peripheral wall of the discharge flow forming tank. Liquid supply means for pressurizing and supplying liquid to the discharge flow forming tank in a jetting direction that forms a swirling flow, and the swirling flow from a gas inlet provided in the discharge flow forming tank so as to face the discharge port. A gas supply means for supplying a gas to the discharge flow forming tank by allowing the gas to be naturally sucked in, and a gas-liquid two-phase flow formed by pressurizing and supplying a liquid to the discharge flow forming tank from the discharge port. It is characterized in that it is diffused and injected into the liquid to be treated.

In this aerator, the liquid supplied into the discharge flow forming tank by the liquid supply means forms a swirling flow along the peripheral wall of the discharge flow forming tank, and flows toward the discharge port while turning inside the tank. Due to this swirling flow, the center of the discharge flow forming tank becomes low pressure, and gas is introduced into the discharge flow forming tank by natural suction from the gas supply means. When gas is introduced into the tank,
The gas is taken into the swirling liquid center to form a gas-liquid two-phase flow. When the gas-liquid two-phase flow is diffused and ejected from the discharge port of the discharge flow forming tank, a gas mass is formed near the discharge port, and the gas mass is subdivided by a large shear force. In addition, a part of the gas introduced into the discharge flow forming tank dissolves in the liquid, and the dissolved gas is reduced due to the pressure drop when the liquid is diffused and injected into the liquid to be processed from the discharge port of the discharge flow forming tank. Precipitates inside and generates fine bubbles. Thereby, a large amount of substantially uniform and fine bubbles can be stably supplied into the liquid to be treated.

According to a second aspect of the present invention, in the aerator, the gas supply means has a control valve for adjusting an amount of gas introduced into the discharge flow forming tank.

In this aerator, the amount of gas introduced into the discharge flow forming tank by the suction effect of the swirling flow is adjusted by the control valve, so that the air inflow amount can be appropriately adjusted according to the use environment. In addition, the bubble size can be further reduced.

The aerator according to a third aspect of the present invention is characterized in that a gas inlet of the gas supply means is provided with a nozzle for stabilizing gas introduction.

In this aerator, the flow of the gas introduced toward the discharge port of the discharge flow forming tank is stabilized, and the flow of the formed gas-liquid two-phase flow in the liquid to be treated is stabilized. Thereby, the shear stress at the interface between the gas-liquid mixed two-phase flow diffused and injected from the discharge flow forming tank and the liquid to be treated outside the discharge flow forming tank can be stabilized.

According to a fourth aspect of the present invention, in the aerator, the discharge flow forming tank has a circular cross section orthogonal to a center axis of the swirling flow, and the liquid supply means is connected to an inner peripheral surface of the discharge flow forming tank. Are connected in a tangential direction.

In this aerator, the liquid is supplied from the liquid supply means, so that the swirling flow is smoothly formed along the inner peripheral surface of the discharge flow forming tank.

According to a fifth aspect of the present invention, in the aerator, the bottom of the discharge flow forming tank is formed in a conical shape protruding in the direction of jetting the gas-liquid two-phase flow.

In this aerator, since the bottom of the discharge flow forming tank is formed in a conical shape, the flow of the swirling flow generated in the discharge flow forming tank can be made smooth and the pressure loss can be reduced.
For this reason, it is possible to achieve a configuration that consumes less power and has high energy efficiency. In addition, since the axial flow velocity distribution of the liquid in the vicinity of the gas inlet nozzle becomes gentle and the suction force is large and stable, the gas introduction amount can be increased accordingly.

The aerator according to a sixth aspect is characterized in that the bottom of the discharge flow forming tank is formed in a flat plate shape.

In this aerator, the discharge flow forming tank can be made simple, the production cost can be reduced, and the size of the aerator can be reduced.

According to a seventh aspect of the present invention, in the aerator of the present invention, the liquid supply means is connected to a wall of the discharge flow forming tank located at a predetermined height from a bottom of the discharge flow forming tank.

In this aerator, the liquid is supplied from a position at a predetermined height from the bottom in the discharge flow forming tank and is continuously swirled between the predetermined heights. Can be uniformly diffused.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a view showing an embodiment of an aerator according to the present invention, FIG. 2 is a configuration diagram of an aerator of the present embodiment, (a) is a longitudinal sectional view, and (b) is A in FIG. 2 (a). FIG. The aerator 100 of the present embodiment is used in a state where it is immersed in a processing tank 2 in which a liquid 1 to be treated is stored as shown in FIG. 1 and has a uniform size of about several tens μm in the liquid 1 to be treated. It is characterized by supplying a large amount of fine bubbles stably.

As shown in FIGS. 1 and 2, the aerator 100 of the present embodiment has a cylindrical peripheral wall and a conical bottom 3a protruding outward. A discharge flow forming tank 3 having a discharge port 4 opened at the center of the tank, a liquid supply means 7 for supplying the liquid W into the discharge flow forming tank 3 through a pipe 5, and a discharge flow through a pipe 8 Gas supply means 9 for introducing air G into the forming tank 3 by natural suction is provided. The processing tank 2 has a volume according to the processing performance of the aerator 100, and as the required processing amount increases or decreases, the processing capacity or the number of aerators corresponding to the processing amount is used as appropriate. Alternatively, a processing tank having a volume corresponding to the processing performance of the aerator is appropriately selected.

The liquid supply means 7 is connected with a pump (not shown) to a pipe 5 communicating with the discharge flow forming tank 3, and pressurizes and supplies the liquid W to the discharge flow forming tank 3 in a state where the pressure is increased. In the present embodiment, the liquid W supplied by the liquid supply means 7 to the discharge flow forming tank 3 is the same as the liquid 1 to be processed stored in the processing tank 2, but is not limited to this. It may be a liquid. The connection angle of the pipe 5 to the discharge flow forming tank 3 defines the direction in which the liquid W supplied to the discharge flow forming tank 3 is jetted, and the liquid W flows along the peripheral wall of the discharge flow forming tank 3. It is set so as to form a swirling flow swirling in the tank. That is, in the present embodiment, FIG.
As shown in the figure, the pipe line 5 is tangentially connected to the inner peripheral surface of the discharge flow forming tank 3. The pipe 5 is connected to the wall of the discharge flow forming tank 3 at a position separated from the bottom of the discharge flow forming tank 3 by a predetermined height, here, at a position close to the height H of the aerator, so that the pipe 5 The supplied liquid continues to swirl in the discharge flow forming tank 3. Thereby, the bias of the swirling flow is eliminated, and the jet is uniformly diffused from the discharge port.

The gas supply means 9 is provided with a gas introduction port 8a so as to face the discharge port 4 of the discharge flow forming tank 3, and supplies air into the tank. The gas inlet 8a is arranged by extending one end of the conduit 8 into the tank so as to be immersed in the liquid in the tank, and a nozzle 10 for stabilizing the introduction of air is provided at the tip thereof. I have. The other end of the pipe 8 is open to the atmosphere, and air at atmospheric pressure is introduced into the discharge flow forming tank 3 by natural suction. Although not shown, it is preferable to provide a control valve for adjusting the air introduction amount in the middle of the pipe 8. Further, in order to simplify the configuration, the gas inlet 8a is provided facing the discharge port 4 at the center of the tank end face opposite to the bottom 3a of the discharge flow forming tank without extending the pipe 8 into the tank. May be adopted.

The bottom 3a of the discharge flow forming tank 3 is shown in FIG.
As shown in (1), it is formed in a conical shape protruding outward in the ejection direction from the discharge port 4 so that the swirling flow smoothly goes to the discharge port 4.

Next, the operation of the aerator 100 will be described. In the aerator 100 having the above configuration, as shown in FIG. 1, a swirling flow is formed in the discharge flow forming tank 3 by pressurizing and supplying the liquid W to the discharge flow forming tank 3 by the liquid supply means 7. After the swirling flow has swirled the inner peripheral surface of the discharge flow forming tank 3,
The flow comes out of the discharge port 4, and the pressure in the central part is reduced in the discharge flow forming tank 3 by the centrifugal force due to the swirling. For this reason, the air G is introduced into the liquid in the tank by the suction action from the gas inlet 8 a to the discharge flow forming tank 3. The air introduced at this time gathers at the center by the swirling flow to form an air core 11, and forms a gas-liquid two-phase flow together with the swirling flow of the liquid.

The gas-liquid two-phase flow formed in the discharge flow forming tank 3 is diffused and injected into the liquid 1 to be processed from the discharge port 4. At this time, an air pocket 12 which is a lump of air injected from the nozzle 10 is formed near the discharge port 4, and fine bubbles are generated by a shearing action at a boundary between the air pocket and the liquid 1 to be treated. When a certain distance from the discharge port 4 is reached, the gas-liquid mixed flow 1 in which the microbubbles 14 are mixed substantially uniformly.
It becomes 6.

In such an aerator 100,
The gas-liquid interfacial tension in the gas-liquid mixed two-phase flow discharged from the discharge port 4 of the discharge flow forming tank 3 is σ _{w / g} , and the gas-liquid mixed two-phase flow and the liquid 1 to be treated outside the discharge flow forming tank 3 are different from each other. Assuming that the shear stress at the interface 18 between S and S is S, and the diameter of the bubble generated in the gas-liquid mixed flow 16 is d _a , the following equation is established. d _a = 4 (σ _{w / g} ) / S

That is, as the shear stress S increases and the gas-liquid interfacial tension σ _{w / g} decreases, the gas-liquid mixed two-phase flow is discharged from the discharge port 4 of the discharge flow forming tank 3. The bubble size in the mixed gas-liquid flow is reduced, and the variation in bubble size is suppressed. Further, the mixing ratio of bubbles in the generated gas-liquid mixed flow 16 is also increased. Therefore, in order to obtain a large amount of small-sized bubbles, the shear stress S at the interface 18 between the gas-liquid mixed two-phase flow and the liquid 1 to be treated is increased, and the interfacial tension σ _{w / g} of the gas-liquid is reduced. It becomes important. According to the aerator of the present embodiment, the air jetted from the discharge port 4 is forcibly passed through the interface having a large shear stress, thereby achieving the miniaturization of the bubble size and the reduction of the variation in the bubble size. ing.

Hereinafter, the effects of the aerator 100 will be described in detail. According to the configuration of the aerator, the gas discharged by the gas supply means 9 stays surrounded by the interface 18 having a large shear stress at a position where the discharge force from the discharge port 4 and the buoyancy of the gas itself are balanced. , Forming an air pocket 12. The gas in the air pocket 12 is dispersed in the liquid to be processed after passing through the interface 18 having a large shear stress, so that the gas in the air pocket 12 is caused to be sheared by the contact between the introduced gas and the interface 18. It is divided efficiently and finely.

Further, since the nozzle 10 is provided at the gas inlet 8a of the gas supply means 9, the state of introduction of the gas introduced from the inside of the discharge flow forming tank 3 toward the outlet 4 is stabilized. The discharge speed of the gas-liquid mixed two-phase flow discharged from the discharge port 4 of the discharge flow forming tank 3 can be stabilized. Thus, it is possible to stabilize the shear stress S at the interface 18 between the gas-liquid mixed two-phase flow diffused and injected from the discharge port 4 of the discharge flow forming tank 3 and the liquid 1 to be treated outside the discharge flow forming tank 3. it can. Comparing the case where the nozzle 10 is mounted and the case where the nozzle 10 is not mounted, the stability of the shear stress S at the interface 18 between the gas-liquid mixed two-phase flow discharged from the aerator 100 and the liquid 1 to be treated outside the discharge flow forming tank 3 The difference in sex is remarkable, and a large amount of fine-sized air bubbles can be discharged stably in the case of wearing. Further, by stabilizing the shear stress S in a large state, the mixing ratio of the fine bubbles 14 in the gas-liquid mixed flow 16 can be increased.

Then, since the pressure of the liquid is increased by the liquid supply means 7 to introduce air into the liquid, the dissolution of air into the liquid is promoted. Further, since the air introduced into the discharge flow forming tank 3 increases the chance of contact between the air and the liquid due to the swirling flow, the dissolution into the liquid is promoted. For this reason, when the gas-liquid two-phase flow is diffused and injected from the discharge port 3 of the discharge flow forming tank 3, the deposition (bubbling) of the dissolved gas in the liquid is promoted by the decompression action.

Further, the swirling force of the liquid supplied into the discharge flow forming tank 3 by the liquid supply means 7 presses the gas flow in the direction of the center of rotation, thereby reducing the pressure when the gas is discharged from the discharge flow forming tank 3. It also has the effect of promoting the deposition of gas and the formation of fine particles, thereby increasing the mixing ratio of bubbles in the gas-liquid mixed flow 16.

Further, by forming the bottom 3a of the discharge flow forming tank 3 in a conical shape, the flow of the swirling flow generated in the discharge flow forming tank becomes smooth and the pressure loss is reduced. For this reason,
An aerator with a low energy requirement and high energy efficiency can be provided. In addition, the axial flow velocity distribution of the liquid in the vicinity of the gas inlet nozzle becomes gentle, and the suction force is large and stable, so that the gas introduction amount can be increased accordingly.

As described above, the aerator 10 of the present embodiment is
In the case of 0, the above effects act synergistically, so that it is possible to stably supply a large amount of fine bubbles having a diameter of about several tens of μm at a constant size. Further, the energy for flowing the liquid and the gas and dispersing the bubbles is small, so that the energy consumption of the entire apparatus can be reduced and the noise can be reduced. Then, in order to supply the liquid under pressure, the stirring action of the liquid is improved, the relative speed between the liquid and the bubbles is increased, the renewal speed of the surface coating of the bubbles is increased, and oxygen is introduced into the liquid to be treated. The moving speed can be improved.

If this aerator 100 is used for purification processing, excellent purification performance can be obtained, and at the same time, the size and cost of the purification device can be reduced. The aerator 100 is operated by combining a plurality of discharge flow forming tanks 3 each having a gas inlet 8a, and branching and connecting a single liquid supply means 7 and a single gas supply means 9. You can also. Therefore, it can be easily adapted to large-capacity processing such as purification of rivers and lakes.

In order to increase the reliability of miniaturization and stabilization of the bubble size, it is preferable to set the dimensions and conditions of each part of the apparatus as follows. V ₁ = 0.1 to 100 m / sec V ₂ = 20 to 200 m / sec d ₀ /D=0.05 to 0.5 d ₁ / d ₀ = 0.1 to 1 h / H = 0 to 1 θ = 30 ° to 180 ° where V ₁ is the flow velocity of the air injected from the nozzle 10,
V ₂ is the flow velocity of the gas-liquid two-phase flow discharged from the discharge port 4, D is the inner diameter of the discharge flow forming tank 3, d ₀ is the inner diameter of the discharge port 4, theta is the apex angle of the bottom 3a, H is the discharge flow formed The height of the tank 3, d ₁ is the inner diameter of the nozzle 10, and h is the height of the nozzle 10 in the tank.

Further, the shape of the discharge flow forming tank 3 is not limited to the cylindrical shape or the combination of the cylinder and the cone in the present embodiment, and the liquid supplied by the liquid supply means flows along the peripheral wall in the tank. For example, the shape may be an ellipsoid or a sphere, as long as the shape forms a swirling flow. That is, the shape of the discharge flow forming tank 3 may be any shape as long as the cross section orthogonal to the center axis of the swirling flow is formed in a circular shape. As described above, by providing a control valve for adjusting the air flow rate in the middle of the pipe 8 of the gas supply means 9 and adjusting the amount of introduced air, the shape of the aerator and fluctuations in operating conditions can be improved. The bubble size can be kept fine and constant, and the operating conditions can be adjusted according to the use environment so that the aerator can always be operated in an optimal state.

Next, a modified example of the aerator of this embodiment will be described. FIG. 3 is a longitudinal sectional view showing the configuration of the aerator of the present modification. This aerator 200 is also used in a state of being immersed in the processing tank 2 in which the liquid 1 to be treated is stored as in FIG. 1, and fine bubbles of a uniform size having a diameter of about several tens μm are formed in the liquid 1 to be treated. Stable mass supply. Note that members having the same functions as in FIG. 2 are given the same reference numerals, and description thereof is omitted here.

The aerator 200 of this modified example includes a discharge flow forming tank 20 having a discharge port 4 opened at the center of a bottomed cylindrical bottom 20a, and the bottom 20a of the discharge flow forming tank 20 has a flat shape. Is formed. According to this configuration, the discharge flow forming tank 20 can be formed into a simple shape that can be easily processed, the manufacturing cost can be reduced, and the size of the aerator can be reduced because there is no protrusion.

[0045]

The results of generating air bubbles using the aerator according to the present invention will be described below. In this embodiment, an aerator having the following dimensions and having the shape shown in FIG. 3 was operated under the conditions of the water inflow pressure, the water flow rate, and the throttle valve opening degree shown in Table 1 to obtain the air flow rate and the air flow rate. The number average cell diameter was measured. Inner diameter D of discharge flow forming tank = 40 mm Height H in discharge flow forming tank H = 40 mm Diameter d ₀ of discharge port 4 = φ6 mm Inner diameter d _{1 of} nozzle 10 = φ1 mm Inner diameter d _{2 of} liquid supply pipe line 5 = φ6 mm The gas supply means is provided with a throttle valve to adjust the amount of air supplied by natural suction.

[0046]

[Table 1]

Table 1 and FIG. 4, which is a graph of Table 1, show the water flow rate (l / min) with respect to the inflow pressure (MPa) of the water supplied from the pipe 5 and the middle of the gas supply pipe 8. Air flow (l / m) for various setting conditions of the opening degree of the throttle valve provided in
in) and the number average cell diameter determined from the number distribution of generated bubbles. "Adjustment" of the throttle valve opening in the table
Means the valve opening when the generated bubbles are substantially fine bubbles, as determined by visual inspection. The air flow rate is a value calculated from the amount of air obtained by collecting generated bubbles in a container for a predetermined time. Under any conditions, when the valve opening is reduced from the state where the throttle valve is fully opened, the bubble size is reduced, and is reduced from about several hundred μm to about several tens μm. Also, as the water pressure increases and the water flow rate increases, the air flow rate increases and the average bubble size tends to decrease.

FIG. 5 is a graph showing the results of confirming the effect of the aerator according to the present invention, showing how the oxygen supply amount and the dissolved oxygen concentration change depending on the air supply method. Here, as the air supply method, a natural suction method, a natural suction method in which the air supply amount is adjusted by a control valve using a natural suction method, and a forced blowing method in which air is forcibly supplied by an air compressor or the like are used. Was. In the case of the natural aspiration type and the adjusted natural aspiration type, the effect of reducing the bubble size is large, and even if the oxygen supply amount is about 1 g / l, the dissolved oxygen concentration is 8%.
mg / l or more, and the dissolved oxygen concentration sharply increases even if the oxygen supply amount is small. In particular, in the regulated natural aspiration type, the dissolved oxygen concentration is 8 m even when the supplied oxygen amount is 0.1 g / l or less.
g / l or more, and the increasing rate of the dissolved oxygen concentration is even greater than in the naturally aspirated type, whereby oxygen can be moved into the liquid to be treated most efficiently. On the other hand, in the forced blowing type, the increasing rate of the dissolved oxygen concentration is smaller than that in the natural aspiration type and the adjusted natural aspiration type, and is greatly reduced.

[0049]

According to the aerator of the present invention, the liquid supply means pressurizes and supplies the liquid into the discharge flow forming tank to form a swirl flow, and the swirl flow causes the gas to be sucked from the gas supply means. Then, it is introduced into the discharge flow forming tank by natural suction. Then, a gas-liquid two-phase flow is formed in the discharge flow forming tank, and the gas-liquid two-phase flow is diffused and ejected from the discharge port of the discharge flow forming tank. This makes it possible to continuously supply a large amount of fine and uniform bubbles in the liquid to be treated with low energy consumption. By using this aerator for the purification process, it is possible to obtain excellent purification performance, and at the same time, it is possible to reduce the size and cost of the purification device.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of an aerator according to the present invention.

2A and 2B are diagrams showing a configuration of an aerator, wherein FIG. 2A is a longitudinal sectional view, and FIG. 2B is a sectional view taken along the line AA in FIG. 2A.

FIG. 3 is a longitudinal sectional view showing a configuration of a modified example of the aerator of the present invention.

FIG. 4 is a graph showing an air flow rate and a number average bubble diameter with respect to various setting conditions of a water flow rate and a throttle valve opening with respect to an inflow pressure of water.

FIG. 5 is a graph showing the results of confirming the effect of the aerator according to the present invention, showing how the oxygen supply amount and the dissolved oxygen concentration change depending on the air supply method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 To-be-processed liquid 2 Processing tank 3, 20 Discharge flow formation tank 3a, 20a Bottom 4 Discharge port 7 Liquid supply means 8a Gas introduction port 9 Gas supply means 10 Nozzle 14 Bubbles 16 Gas-liquid mixture flow 100, 200 Aerator G Air W Liquid

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yoshio Yoshimi 8-1 Hirai Hinodemachi, Nishitama-gun, Tokyo Nippon Steel Mining Co., Ltd. (72) Inventor Michio Nonaka 1-31-20F Shimotakaido, Suginami-ku, Tokyo Terms (reference) 4D029 AA09 AB01 BB11 4G035 AB16 AC44 AE13

Claims (7)

[Claims] 1. An aerator that supplies fine gas bubbles to a liquid to be processed by discharging a gas-liquid two-phase flow formed by taking a gas phase into a liquid into the liquid to be processed. A discharge flow forming tank immersed in the liquid to be treated, and a liquid for pressurizing and supplying the liquid to the discharge flow forming tank in a jetting direction of a swirling flow swirling in the tank along the peripheral wall of the discharge flow forming tank. A supply unit, and a gas supply unit that supplies gas to the discharge flow forming tank by causing the gas to be naturally sucked by the swirling flow from a gas introduction port provided in the discharge flow forming tank so as to face the discharge port. An aerator, wherein a gas-liquid two-phase flow formed by pressurizing and supplying a liquid to the discharge flow forming tank is diffused and injected into the liquid to be processed from the discharge port. 2. The aerator according to claim 1, wherein said gas supply means has a control valve for adjusting an amount of gas introduced into said discharge flow forming tank. 3. The aerator according to claim 1, wherein a nozzle for stabilizing gas introduction is provided at a gas introduction port of the gas supply means. 4. The discharge flow forming tank has a circular cross section perpendicular to a swirling center axis of the swirling flow, and the liquid supply means is tangentially directed to an inner peripheral surface of the discharge flow forming tank. The aerator according to any one of claims 1 to 3, wherein the aerator is connected. 5. The discharge flow forming tank according to claim 1, wherein a bottom portion of the discharge flow forming tank is formed in a conical shape protruding in a jet direction of the gas-liquid two-phase flow. Aerator. 6. The discharge flow forming tank according to claim 1, wherein the bottom of the discharge flow forming tank is formed in a flat plate shape.
The aerator according to the item. 7. The discharge flow forming tank according to claim 1, wherein the liquid supply means is connected to a wall of the discharge flow forming tank located at a predetermined height from a bottom of the discharge flow forming tank. The aerator according to the item.