JP6746298B2 - Micro bubble generation system - Google Patents

Description

The present invention relates to a microbubble generation system.

The micro bubbles having a size of less than 1 μm mixed in the liquid are also called ultra fine bubbles. Ultrafine bubbles in the liquid have a diameter shorter than the wavelength of visible light, and therefore, scattering of visible light does not occur in the liquid. Therefore, even if the liquid containing the ultra fine bubbles is visually observed, the presence of the ultra fine bubbles cannot be visually confirmed, and the liquid remains transparent. Further, it is known that the ultra fine bubbles mixed in the liquid exist in a state of being suspended in the liquid and remain in the liquid for a long time (for example, several months).

Water mixed with ultrafine bubbles (hereinafter referred to as "UFB-containing water") has higher detergency than normal water, has a high oxygen content, and does not contain chemical substances and is easy to be post-treated. Therefore, it is used in the fields of washing industrial products and foods, wastewater treatment, beauty, aquaculture, hydroponic cultivation, and the like.

In Patent Document 1 below, a micro-bubble generating device has a cylindrical body that extends vertically and in which a fluid flows from one end side to the other end side, and an axial direction is vertically arranged in the cylindrical body to form an uneven portion. It is described that a rotor having an outer peripheral surface, a stator having an inner peripheral surface in which a concavo-convex portion is formed in a cylindrical body, and a motor connected to the rotor to rotate the rotor are described. Then, when the motor is driven to rotate the rotor with respect to the stator, the uneven portions relatively move in the circumferential direction, and compression and opening forces are periodically applied to the fluid in the fluid passage, so that the fluid is It is contracted and expanded periodically. As a result, it is described that when the microbubble generator is applied to a hydrogen water production apparatus, hydrogen gas becomes microbubbles and is contained in water.

Japanese Patent No. 5475273

The UFB-containing water has the effect of enhancing the detergency when the density of ultrafine bubbles is high, and the UFB-containing water having a high density can be diluted before use. Therefore, if UFB-containing water with a high density of ultrafine bubbles can be generated using the ultrafine bubble generator, UFB-containing water with high detergency can be generated, and the ultrafine bubble generator can be operated efficiently. There are advantages.

The inventors of the present invention have found that in the micro-bubble generating device including the rotor and the stator as described in Patent Document 1 described above, the bubble density can be increased by adjusting the rotor rotation speed. Is obtained by. However, there is a limit to the range in which the bubble density can be increased only by adjusting the rotor rotation speed, and it has been difficult to increase the bubble density above a certain level with respect to the generated UFB-containing water.

Further, as a result of studying the micro-bubble generating device by the inventors of the present application, it is said that the bubble density can be increased by increasing the surface areas of the rotor and the stator that exert a shearing force on the fluid between the rotor and the stator. Knowledge is obtained. Therefore, the inventors of the present application have invented a microbubble mixed fluid generation device including a rotor and a stator described in, for example, Japanese Patent Application No. 2014-157688, and can increase the bubble density of UFB-containing water generated. However, it has been desired to produce UFB-containing water having a higher bubble density.

The present invention has been made in view of such circumstances, and provides a microbubble generation system capable of efficiently generating a microbubble-containing liquid having a high bubble density of ultrafine bubbles having a diameter of less than 1 μm. The purpose is to

In order to solve the above problems, the microbubble generation system of the present invention employs the following means.
That is, the microbubble generating system according to the present invention stores a gas-containing liquid supplied from the pump, and a pump that is supplied with the liquid and takes in gas while boosting the pressure of the gas and transfers the gas-containing liquid. Ultra fine bubble generation device for generating an ultra fine bubble containing liquid, which has a pressure tank, a rotor for applying a shearing force to a gas containing liquid supplied from the pressure tank and decompressed, and a motor for rotating the rotor. With.

According to this configuration, after the gas is dissolved in the liquid in the pressure tank, the pressure of the liquid is reduced, the dissolved gas is made into bubbles, and the bubbles contained in the liquid are further subdivided by the ultrafine bubble generation device. As a result, the bubble density of ultrafine bubbles can be increased.

The above invention may further include a liquid tank for storing the ultrafine bubble-containing liquid supplied from the ultrafine bubble generation device and supplying the stored ultrafine bubble-containing liquid to the pump.

With this configuration, the ultrafine bubble-containing liquid generated by the ultrafine bubble generation device can be circulated repeatedly, and the bubble density of the ultrafine bubbles can be increased.

In the above invention, the liquid tank includes a first tank and a second tank which are partitioned from each other by a partition plate, and the first tank is supplied with the ultrafine bubble-containing liquid from the ultrafine bubble generating device, The second tank is supplied with the ultrafine bubble-containing liquid from the first tank over the upper end of the partition plate.

According to this configuration, the liquid stored in the first tank supplied from the ultrafine bubble generator is filled up to the upper end of the partition plate, and then is supplied to the second tank over the upper end of the partition plate. At this time, after bubbles having a relatively large diameter rise to the liquid level in the first tank, the bubbles floating on the water surface at the upper end of the partition plate are blocked and disappear, so that the liquid supplied to the second tank It is possible to reduce bubbles having a relatively large diameter included in the above.

In the above invention, the partition plate has an inclined plate provided on an upper end thereof and inclined downward from the first tank to the second tank.

According to this structure, when the ultrafine bubble-containing liquid is supplied from the first tank to the second tank over the upper end of the partition plate, the ultrafine bubble-containing liquid flows on the inclined plate. At this time, on the inclined plate, the flow velocity Va of the liquid near the plate surface becomes lower than the flow velocity Vb of the liquid near the surface due to the resistance of the plate surface. As a result, the bubbles in the flow of the liquid are attracted to the surface side having a high velocity, and the bubbles having a relatively large diameter contained in the liquid easily come into contact with the air, so that the ability to eliminate the bubbles can be improved.

In the above invention, a pipe connecting the pressure tank and the ultra fine bubble generator may be further provided, and a first valve provided in the pipe for adjusting the pressure in the pressure tank may be further provided.

According to this configuration, the pressure in the pressure tank is adjusted by the first valve, and for example, the pressure in the pressure tank can be increased and the bubble density can be increased.

In the above invention, the rotation speed of the motor of the ultrafine bubble generation device may be adjustable.

According to this configuration, the rotation speed of the motor is adjusted. For example, the bubble density can be increased by increasing the rotation speed of the motor to increase the rotation speed of the rotor.

In the above invention, a second valve provided in the pump and capable of adjusting the amount of gas taken in by the pump may be further provided.

According to this configuration, the ratio of the amount of air taken in by the pump to the amount of circulating liquid can be changed, and the bubble density can be increased by setting the ratio appropriately.

In the above invention, a cooling device for cooling the liquid containing ultrafine bubbles stored in the liquid tank may further be provided.

According to this configuration, the temperature of the ultrafine bubble-containing liquid that rises by passing through the ultrafine bubble generation device and is supplied to the liquid tank can be lowered. To cool the ultrafine bubble-containing liquid stored in the liquid tank, install another cooling water tank outside the liquid tank and cool the ultrafine bubble-containing liquid in the liquid tank with the low-temperature cooling water tank. The cooling coil may be inserted into the liquid containing ultrafine bubbles in the liquid tank to cool the liquid containing ultrafine bubbles.

According to the present invention, it is possible to efficiently generate a microbubble-containing liquid having a high bubble density of ultrafine bubbles having a diameter of less than 1 μm.

It is a block diagram which shows the microbubble generation system which concerns on one Embodiment of this invention. It is a graph which shows the relationship between bubble density and the pressure in a pressure tank. It is a graph which shows the relationship between a bubble density and the relative rotor rotation speed in an ultrafine bubble generator. It is a graph which shows the relationship between the average particle diameter of the bubble in ultrafine bubble containing water, and relative rotor rotation speed. 6 is a graph showing the relationship between bubble density and operating time when the air supply amount is changed. 6 is a graph showing the relationship between bubble density and operating time when the rotor speed is changed. 6 is a graph showing the relationship between bubble density and operating time when the presence or absence of a pressure tank is changed while rotating the rotor of the ultrafine bubble generation device. It is a longitudinal section of a fluid shearing part showing one embodiment of the present invention. FIG. 9 is a cross-sectional view taken along the line IX-IX in FIG. 8. It is sectional drawing which shows one Example of a rotor. It is a longitudinal cross-sectional view which shows the 1st modification of the water tank of the microbubble generation system which concerns on one Embodiment of this invention. It is a longitudinal cross-sectional view which shows the 2nd modification of the water tank of the microbubble generation system which concerns on one Embodiment of this invention.

Embodiments according to the present invention will be described below with reference to the drawings.
The microbubble generation system according to the present embodiment mixes air with water to generate microbubble-containing water (hereinafter referred to as “UFB-containing water”) containing ultrafine bubbles having a diameter of less than 1 μm. The microbubble generation system according to the present invention may be applied to liquids other than water, and the gas contained in the liquid and forming bubbles is not limited to air, but may be oxygen, carbon dioxide, nitrogen, hydrogen, or the like. Good.

As shown in FIG. 1, the microbubble generation system 100 includes a pump 102, a pressure tank 103, a first valve 104, an ultrafine bubble generation device (hereinafter referred to as “UFB generation device”) 105, and a water tank 106. A circulation pipe 107, etc., which is connected between these components and circulates water, is provided.

The pump 102 pressurizes while introducing air into the water flowing through the circulation pipe 107. The pump 102 sucks the water stored in the water tank 106, takes in the air in the atmosphere, and discharges the air-containing water. At this time, the water flowing inside the pump 102 is stirred by the blades of the pump 102, and the air-containing water discharged from the pump 102 is mixed with fine bubbles. The air-containing water discharged by the pump 102 is supplied to the pressure tank 103.

The pump 102 is provided with an air intake port that takes in air. A second valve 108 or the like may be provided at the air intake port so that the intake amount of air can be adjusted. In addition, in the present embodiment, the pump 102 has a configuration that directly takes in air from the atmosphere, but, for example, the pump 102 may be connected to a cylinder or the like to take in gas from the cylinder.

The pressure tank 103 temporarily stores the air-containing water supplied from the pump 102, and supplies the air-containing water to the UFB generation device 105 via the first valve 104. The pressure in the pressure tank 103 is adjusted by changing the throttle amount of the first valve 104.

The high pressure in the pressure tank 103 causes air to dissolve in water. After that, when the pressure is supplied from the pressure tank 103 to the UFB generator 105, the pressure is reduced, and the air dissolved in the water is contained in the water as bubbles. Most of the bubbles at this time are so-called micro bubbles having a size of 1 μm or more.

A branch pipe 120 is connected to the circulation pipes 107 before and after the pump 102, and the branch pipe 120 is provided with a third valve 119. When the third valve 119 is in the open state, the air-containing water branches from the circulation pipe 107 on the downstream side of the pump 102, flows into the branch pipe 120, and joins with the upstream side of the pump 102. When the throttle amount of the first valve 104 is changed, by adjusting the throttle amount of the third valve 119, the flow rate of the air-containing water flowing through the circulation pipe 107 can be made constant. The flow rate of the air-containing water flowing through the circulation pipe 107 is measured, for example, on the downstream side of the UFB generation device 105.

The UFB generation device 105 applies a force to the water supplied from the pressure tank 103 via the first valve 104 so as to shear the water between the outer peripheral surface of the rotor and the inner peripheral surface of the casing. As a result, the UFB generator 105 finely subdivides the bubbles existing in the water to reduce the bubble size and increase the number of bubbles. As a result, the density of ultrafine bubbles contained in the air-containing water increases.

In the UFB generation device 105, an inverter motor is installed vertically with its main shaft facing vertically upward, and a cylindrical fluid shearing part is installed on the upper part. The fluid shearing section will be described later.

The UFB generator 105 supplies the generated UFB-containing water to the water tank 106.

The water tank 106 is a container that stores UFB-containing water. When the microbubble generation system 100 is in operation, the UFB-containing water is supplied from the UFB generation device 105 to the water tank 106, and the stored UFB-containing water is supplied from the water tank 106 to the pump 102.

As shown in FIG. 1, the water tank 106 may include a first tank 113 and a second tank 114 that are separated from each other by a partition plate 112. The UFB-containing water is supplied from the UFB generator 105 to the first tank 113, and the UFB-containing water is supplied to the second tank 114 from the first tank 113 over the upper end of the partition plate 112. The UFB-containing water stored in the first tank 113 supplied from the UFB generator 105 is filled up to the upper end of the partition plate 112, and then is supplied to the second tank 114 over the upper end of the partition plate 112. The UFB-containing water stored in the second tank 114 is supplied from the second tank 114 to the pump 102.

At this time, after bubbles having a relatively large diameter (for example, bubbles having a diameter larger than that of micro bubbles) rise to the liquid surface of the first tank 113, the bubbles floating on the water surface are blocked by the upper end of the partition plate 112. As a result, the bubbles contained in the liquid supplied to the second tank 114 and having a relatively large diameter can be reduced. Further, in the second tank 114, since there are few bubbles having a relatively large diameter, it is possible to prevent the bubbles existing in the liquid in the second tank 114 from joining, coalescing and coalescing.
The first tank 113 may be provided with a water flow forming plate 115 having an opening 116 formed near the bottom surface. As a result, a water flow from the bottom to the top can be formed inside the first tank 113.

A water cooling device 109 for cooling the water tank 106 may be provided around the water tank 106. The water cooling device 109 includes a cooling water tank 110 for immersing the water tank 106 in cooling water, a cooling coil 111 provided in the cooling water tank 110, and the like. The medium cooled by the chiller flows in the cooling coil 111, and the cooling coil 111 lowers the temperature of the cooling water in the cooling water tank 110. As a result, the temperature of the UFB-containing water in the water tank 106 that rises by passing through the UFB generator 105 and is supplied to the water tank 106 can be lowered by the cooling water in the cooling water tank 110.

In order to reduce the temperature of the UFB-containing water in the water tank 106, the cooling coil may be installed inside the UFB-containing water stored in the water tank 106 without providing the water cooling device 109. Thereby, the temperature of the UFB-containing water in the water tank 106 supplied to the water tank 106 can be lowered by the cooling coil.

In the microbubble generation system 100 described above, water is stored in the water tank 106 before the operation is started. Further, the opening degree of the second valve 108 provided at the air intake port is adjusted according to the amount of air supplied to the pump 102, and the first valve 104 is opened according to the pressure in the pressure tank 103. Adjust the degree. Further, the opening degree of the third valve 119 is also adjusted according to the opening degree of the first valve 104. Further, the number of rotations of the rotor of the UFB generator 105 is also set.

The adjustment of the supply air amount by the second valve 108, the adjustment of the pressure in the pressure tank 103 by the first valve 104, and the like are not limited to before the operation is started, and may be appropriately performed without stopping the operation during the operation. Is. For example, when the temperature of the air-containing water circulating through the microbubble generation system 100 rises during operation, the amount of dissolved gas in the water decreases, so that the second valve 108 is throttled to collect air in the pressure tank 103. It needs to be prevented. Further, when the temperature of the circulating air-containing water rises, the viscosity of the water decreases and the circulation flow rate increases, so it is necessary to squeeze the first valve 104 and the third valve 119 to finely adjust the circulation flow rate in the decreasing direction. ..

Then, the operation of the pump 102 and the UFB generator 105 is started, and water is circulated in the circulation pipe 107. In the pump 102, while the water is supplied from the water tank 106, the air is taken in from the atmosphere and the air-containing water is generated. The air-containing water generated by the pump 102 is supplied to the pressure tank 103 and temporarily stored in the pressure tank 103. In the pressure tank 103, the pressure of the air-containing water becomes high, and the air dissolves in the water.

The air-containing water stored in the pressure tank 103 is supplied to the UFB generator 105 via the first valve 104. When passing through the first valve 104, the pressure of the air-containing water decreases, and the air dissolved in the water becomes bubbles and is contained in the water. Therefore, the UFB generator 105 is supplied with water containing bubbling air.

In the UFB generation device 105, a shearing force acts on water containing bubbling air so as to shear between the outer peripheral surface of the rotor and the inner peripheral surface of the casing. As a result, the bubbles existing in the water are finely subdivided, the bubble size is reduced and the number of bubbles is increased.

After that, the UFB-containing water generated by the UFB generation device 105 is supplied to the water tank 106. The UFB-containing water supplied to the water tank 106 is temporarily stored in the water tank 106 and is again supplied to the pump 102. Water repeatedly circulates within the microbubble generation system 100 during operation. As a result, the density of ultrafine bubbles contained in water increases.

As described above, according to the present embodiment, after dissolving air in water in the pressure tank 103, decompressing the water makes the dissolved air into bubbles, and further the bubbles contained in the water in the UFB generation device 105 are removed. The number of bubbles is increased while subdividing to reduce the bubble size. This makes it possible to efficiently generate UFB-containing water having a high bubble density.

Next, the results when UFB-containing water is generated by actually applying the above-described microbubble generation system 100 will be described.

In the following, in the microbubble generation system 100, the circulation flow rate is 7 L/min and the water amount is 20 L. Therefore, if the circulation is continued for 1 hour (60 minutes), the water in the microbubble generation system 100 is circulated 21 times (21 Pass). The water was maintained at around 35°C. In the UFB generator 105, the gap between the inner peripheral surface of the casing and the outer peripheral surface of the rotor is 0.5 mm. The water circulated in the microbubble generation system 100 was pure water that was ion-exchanged after distillation. In addition, a nanoparticle analyzer (NanoSight LM10) was used to measure the bubble density of the ultra fiber bull contained in the UFB-containing water, and the measurement sensitivity was set to the default value. When the pressure in the pressure tank 103 is changed, the throttle amount of the first valve 104 is adjusted, and the throttle amount of the third valve 119 is also adjusted at the same time in order to keep the circulation flow rate constant.

FIG. 2 is a graph showing the relationship between the bubble density and the pressure inside the pressure tank 103. When the operation time of the microbubble generation system 100 was set to 60 minutes, the pressure in the pressure tank 103 was changed, and as a result, the bubble density shown in FIG. 2 was obtained.

As a result, as compared with the case where the UFB-containing water is generated without using the pressure tank 103 (the pressure in the pressure tank is 0 kPa), the case where the UFB-containing water is generated using the pressure tank 103 has a higher bubble density. You can see that it can be increased. Further, the higher the pressure in the pressure tank 103, the higher the bubble density. For example, when the pressure is 0.2 MPa, it is 1×10 ⁸ cells/mL, whereas when the pressure is 0.5 MPa, it is 4×10 ⁸ to 5×10 ⁸ cells/mL.

FIG. 3 is a graph showing the relationship between the bubble density and the relative rotor speed in the UFB generator 105. When the operating time of the micro-bubble generation system 100 is 60 minutes and the amount of air taken in by the pump 102 is 8% of the circulation flow rate (since the circulation flow rate is 7 L/min, the air amount is 0.56 L/min). In Fig. 3, as a result of changing the rotor rotation speed, the bubble density obtained was the result shown in Fig. 3. The horizontal axis of the graph in FIG. 3 indicates that when the pressure in the pressure tank 103 is 0.5 MPa, the bubble density is 2.4×10 ⁸ cells/mL, and when the pressure is 0.18 MPa, 0.25×10 ⁸ cells/mL. When the rotor rotational speed is 1.0, the rotor rotational speed is 1.0 and is represented by a relative value.

As a result, when the pressure in the pressure tank 103 is the same (0.5 MPa in this embodiment), the rotor is not rotated, that is, the rotor is rotated as compared with the case where the UFB generator 105 is not used. It can be seen that the bubble density can be increased. Further, the higher the rotor speed, the higher the bubble density. For example, when the pressure is 0.5 MPa, it is 2.4×10 ⁸ cells/mL, whereas it is 4×10 ⁸ cells/mL when the rotor rotation speed is slightly doubled. When the pressure is 0.18MPa, it is 0.25×10 ⁸ pcs/mL, whereas when the rotor speed is slightly doubled, it is from 1×10 ⁸ pcs/mL to 2×10 ⁸ pcs/mL. is there.

Further, FIG. 4 is a graph showing the relationship between the average particle diameter of bubbles in UFB-containing water and the relative rotor rotational speed. When the operation time of the micro-bubble generation system 100 is 60 minutes and the amount of air taken in by the pump 102 is 8% of the circulation flow rate, the rotor rotation speed is changed, and the average particle size is shown in FIG. The results shown were obtained. The horizontal axis of the graph in FIG. 4 is the same as the horizontal axis of the graph in FIG. 3, and when the pressure in the pressure tank 103 is 0.5 MPa, the bubble density is 2.4×10 ⁸ cells/mL and the pressure is 0.18. In the case of MPa, it is a relative value with the rotor speed of 1.0 at 0.25×10 ⁸ pieces/mL.

As a result, when the pressure in the pressure tank 103 is the same (0.5 MPa in this embodiment), the average particle size is about 120 nm to 130 nm both when the rotor is not rotated and when the rotor is rotated. There was no significant difference between the two. Also, the average particle size was about 120 to 130 nm both when the pressure was 0.5 MPa and when the pressure was 0.18 MPa, and no significant difference was observed between the two.

From the above, it can be seen that ultrafine bubbles are generated even when the rotor is not rotated. However, in order to increase the bubble density, the rotor tank speed should be set high while the pressure tank 103 pressure is increased. I know that is good.

FIG. 5 is a graph showing the relationship between the bubble density and the operating time when the air supply amount is changed. When the pressure in the pressure tank 103 was set to 0.5 MPa, the air taken in by the pump 102 was changed, and as a result, the increase in bubble density with the increase in operating time was as shown in FIG.

It can be seen that the bubble density rises as the operating time increases both when the air volume ratio taken in by the pump 102 is 8% and when it is 16%. Further, when the air taken in by the pump 102 is set to 16%, no significant difference can be seen up to about 60 minutes of operation time compared to the case where it is set to 8%, but the bubble density is low after 90 minutes. The result has been obtained. It is considered that this is because when the ratio of the amount of air taken in by the pump 102 is 16%, the amount of air dissolved in water is limited, and the amount of air accumulated in the pressure tank 103 without being dissolved in water increases. .. On the other hand, when the air volume ratio taken in by the pump 102 is set to a low value close to 0%, it is presumed that the result that the bubble density does not increase can be obtained. Therefore, it is recognized that the air supply amount has an appropriate value.

FIG. 6 is a graph showing the relationship between bubble density and operating time when the rotor rotation speed is changed. When the pressure in the pressure tank 103 is set to 0.5 MPa, the presence or absence of air taken in by the pump 102 and the presence or absence of rotation of the rotor are made different, and as a result, the increase in bubble density with the increase in operating time is shown in FIG. The following results were obtained.

No air taken in by the pump 102, no rotor rotation, when the air amount taken in by the pump 102 is 8%, with rotor rotation, and when the air amount taken by the pump 102 is 8%, no rotor rotation A comparison was made for the three cases with and without.

When there is no air taken in by the pump 102 and no rotor rotation, air is not taken in by the pump 102, and there is no air that is a generation source of microbubbles. Therefore, the measured bubble density value is , Indicates background or noise. On the other hand, when the ratio of the amount of air taken in by the pump 102 is 8% and the rotor is not rotated, that is, when the air is taken in by the pump 102 but the UFB generation device 105 is not operated, the pressure tank 103 is used. It shows the bubble density of the micro bubbles generated when the air dissolved in water is released. In this case, the bubble density was 1.47×10 ⁸ cells/mL after 60 minutes of operation. On the other hand, when the air taken in by the pump 102 is 8% and the rotor is rotated, that is, when the UFB generation device 105 is operated, the air bubbles dissolved in water in the pressure tank 103 are released into fine bubbles. In addition, the density of micro bubbles generated in the UFB generator 105 is shown. In this case, the bubble density was 4.28×10 ⁸ cells/mL after 60 minutes of operation. That is, it can be seen that by operating the UFB generator 105, the bubble density increases about three times in 60 minutes of operation time. Therefore, it can be said that the ratio of ultrafine bubbles generated in the UFB generation device 105 is high.

FIG. 7 is a graph showing the relationship between bubble density and operating time when the presence or absence of the pressure tank 103 is changed while rotating the rotor of the UFB generator 105. When the rotor was rotated, the presence or absence of the pressure tank 103 was changed, and as a result, an increase in bubble density with an increase in operating time was obtained as shown in FIG. 7.

When the rotor was rotated without providing the pressure tank 103, the bubble density was 0.3 to 0.5×10 ⁸ cells/mL after 60 minutes of operation. On the other hand, when the pressure tank 103 is provided and the rotor is rotated, the bubble density becomes 4×10 ⁸ cells/mL in 60 minutes, which is about 10 times as high as that without the pressure tank 103. It turns out that In addition, when the pressure tank 103 is provided and the rotor is rotated, it is found that the bubble density continues to increase as the operating time increases, and the bubble density is 10×10 ⁸ cells/mL in 210 minutes of operating time. Became.

From the above, after air is dissolved in water in the pressure tank 103, the water is decompressed to make the dissolved air into bubbles, and further, by subdividing the bubbles contained in the water in the UFB generation device 105, It can be said that the bubble density of ultrafine bubbles can be increased significantly. In addition, as an operating condition for increasing the bubble density, the air amount ratio taken into the pump 102 has an appropriate amount, while the higher the pressure in the pressure tank 103, the higher the bubble density can be. The higher the rotor speed, the higher the bubble density can be.

It has been observed that when the UFB generation device 105 is not operated, that is, the water containing microbubbles generated after passing through the pressure tank 103 is cloudy and floats on the water surface and bursts. Therefore, microbubbles, which are larger in size than ultrafine bubbles, are dominant. On the other hand, when the UFB generation device 105 is operated, it is measured that ultrafine bubbles remain in the generated microbubble-containing water for a long time, and the obtained microbubble-containing water is not clouded. Has been observed. Therefore, micro bubbles are hardly generated, and water in which ultra fine bubbles are dominant is obtained.

In the microbubble generation system 100 according to the present embodiment described above, the type of microbubble-containing water that is finally obtained can be changed by switching whether the operation of the UFB generation device 105 is started or stopped. it can. That is, by starting the operation of the UFB generation device 105, it is possible to obtain the ultrafine bubble-containing water containing fine bubbles, and by stopping the operation of the UFB generation device 105, Obtainable. Ultrafine bubble-based microbubble-containing water is used for cleaning or sterilization, and microbubble-based microbubble-containing water is used for water treatment by flotation separation, baths and the like.

Further, according to the present embodiment, by adjusting the pressure in the pressure tank 103 and the rotation speed of the UFB generation device 105, high density UFB-containing water can be obtained. The high-density UFB-containing water has high cleaning or sterilizing power. Further, since the high-density UFB-containing water can be diluted, by generating the high-density UFB-containing water by the microbubble generation system 100 according to the present embodiment, a large amount of UFB-containing water is efficiently generated. it can.

The fluid shearing section 8 will be described below.

First, as shown in FIG. 8, a partition plate 11 formed of a thick steel plate or the like is fastened to a plurality of bolts 12, and a cylindrical bearing holder 13 extending through the partition plate 11 along the vertical direction is formed. It is fixed. Further, an outer casing 15 having a cylindrical container shape having a diameter larger than that of the bearing holder 13 and having an upper portion closed off is detachably fixed to the upper surface of the partition plate 11 by a plurality of bolts 16. An O-ring 17 liquid-tightly seals between the partition plate 11 and the outer casing 15.

Further, as shown in FIG. 9, a cylindrical inner casing 19 is detachably fixed to the outer peripheral surface of the bearing holder 13. A main shaft 7, a bearing holder 13, an outer casing 15, an inner casing 19, and an inner rotor 27 described later of an inverter motor (not shown) are arranged in a straight line along a common vertical central axis C. As shown in FIGS. 8 and 9, the inner peripheral surface of the outer casing 15 has a fixed-side fluid shear surface 15a, and the outer peripheral surface of the inner casing 19 has a fixed-side fluid shear surface 19a. These fixed-side fluid shear surfaces 15a and 19a are formed around a common central axis C, have different diameters, and overlap in the radial and axial directions. The fixed-side fluid shear surfaces 15a and 19a are uneven as will be described later.

As shown in FIG. 8, the vertical drive shaft 23 is rotatably supported around the central axis C by a pair of upper and lower bearings 21 and 22 (bearings) press-fitted into the upper and lower ends of the bearing holder 13. Is connected to the main shaft 7 of the inverter motor via a joint 24. A cylindrical inner rotor 27 that covers the inner casing 19 is fixed to the upper portion of the drive shaft 23 by, for example, a plurality of bolts 28 so as to be integrally rotated and detachably attached to the drive shaft 23. That is, the inner rotor 27 is cantilevered from below by the bearings 21 and 22 and the drive shaft 23, and if the outer casing 15 is removed, the bolt 28 is pulled out to free the axial end ( Here it can be removed towards the top).

The inner rotor 27 is rotationally driven by the inverter motor and rotates inside the outer casing 15. Here, of the bearings 21 and 22 that axially support the inner rotor 27, the upper bearing 22 is arranged at an axially intermediate portion of the inner rotor 27. That is, the bearing 22 is arranged at a height between the lower end portion 27c and the upper end portion 27d of the inner rotor 27. A mechanical seal 30 is provided above the bearing holder 13 to prevent the drive shaft 23 from coming off and to prevent the drive shaft 23 from being waterproof.

As shown in FIGS. 8 and 9, the outer peripheral surface of the inner rotor 27 has a movable fluid shearing surface 27a facing the fixed fluid shearing surface 15a of the outer casing 15 with a space of, for example, 0.5 mm to 3 mm. Has become. The inner peripheral surface of the inner rotor 27 is a movable fluid shear plane 27b that faces the fixed fluid shear plane 19a of the inner casing 19 with a gap of, for example, 0.5 mm to 3 mm. The fluid shear spaces 31, 32 are respectively provided between the fixed-side fluid shear planes 15a, 19a of the outer casing 15 and the inner casing 19 and the movable-side fluid shear planes 27a, 27b of the inner rotor 27, which face the fixed side fluid shear planes 15a, 19a, respectively. Are formed. The fluid shear spaces 31 and 32 have different diameters, overlap in the radial direction and the axial direction, and communicate with each other. That is, the fluid shear space 32 has a smaller diameter than the fluid shear space 31 and overlaps with the inner circumferential side of the fluid shear space 31, and a communication passage 33 formed between the inner rotor 27 and the partition plate 11 is interposed therebetween. Communicate with each other.

In each of these fluid shear spaces 31, 32, an uneven fluid shear shape is formed on at least one of the fixed-side fluid shear surfaces 15a, 19a and the movable-side fluid shear surfaces 27a, 27b. For example, in the fluid shear space 31, both the fixed fluid shear plane 15a and the movable fluid shear plane 27a are provided with an uneven fluid shear shape such that the cross section orthogonal to the central axis C is gear-shaped. (It is described in a simplified manner in FIG. 9).
Further, in the fluid shear space 32, similar fixed (shear-like) fluid shear shapes are given to both the fixed fluid shear surface 19a and the movable fluid shear surface 27b. (Simplified in FIG. 9)
The fixed-side fluid shear surface 19a has a large number of slit grooves extending in the axial direction over the entire circumference of the cylindrical inner casing 19, and the inner casing 19 is formed on the outer peripheral surfaces of the bearing holder 13 and the mechanical seal 30. By closely fitting, the cross-sectional shape at the position of the slit groove is formed into an uneven shape.

As shown in FIG. 8, a fluid inlet portion 36 is provided at the center of the upper surface of the outer casing 15, and a fluid outlet portion 37 is provided at the upper outer peripheral surface of the outer casing 15. The fluid inlet portion 36 allows water, in which a gas such as air and oxygen is mixed by the pump 102 and the pressure tank 103, to flow from the rotation center portion of the inner rotor 27 into the fluid shear space 32 on the upstream side on the radially inner side. Is provided. Further, the fluid outlet portion 37 is provided so as to allow water to flow out from the fluid shear space 31 on the downstream side, which is on the radially outer side.

Specifically, the fluid inlet portion 36 is, for example, a tubular shape fixed to the central portion of the upper surface of the outer casing 15 along the central axis C, and is formed along the axial center from the upper end portion of the drive shaft 23. It communicates with the cardiac inflow passage 40. Since the drive shaft 23 (shaft center inflow passage 40) rotates relative to the fluid inlet port 36, relative rotation between the members 36 and 40 is possible between the fluid inlet port 36 and the shaft center inlet passage 40. In addition, a seal member (not shown) that prevents water from flowing into the fluid shear space 31 on the downstream side from the fluid inlet portion 36 is interposed.

As shown in FIG. 8, the drive shaft 23 is formed with a plurality of horizontal passages 41 that extend horizontally from the lower end of the shaft center inflow passage 40. These horizontal passages 41 are formed inside the inner rotor 27, respectively. The plurality of vertical passages 42 communicate with each other, and each vertical passage 42 communicates with the fluid shear space 32. Therefore, the water flowing in from the fluid inlet portion 36 is supplied to the fluid shear space 32 through the axial inflow passage 40, the horizontal passage 41, and the vertical passage 42.

On the other hand, the fluid outlet portion 37 has a pipe shape that extends horizontally in a tangential direction to the outer peripheral contour of the outer casing 15 in a plan view, and communicates with the uppermost portion of the fluid shear space 31 as shown in FIG. 8. ing. Then, as the inner rotor 27 rotates, the water in the fluid shear space 31 on the downstream side flows out from the fluid outlet portion 37.
The fluid shearing section 8 is configured as described above.

FIG. 10 shows an example of the cross-sectional shape of the fluid shearing section 8 of the UFB generator 105 used when performing the measurement described with reference to FIGS. 2 to 7.

The fixed fluid shear planes 15a of the outer casing 15, the fixed fluid shear planes 19a of the inner casing 19, and the movable fluid shear planes 27a of the inner rotor 27 have uneven concave and convex fluid shear shapes. The concave and convex fluid shearing shapes of the movable-side fluid shearing surface 27b of the inner rotor 27 are grooves having a substantially semicircular cross section.

In addition, in the above-described embodiment, the case where the water tank 106 includes two tanks, that is, the first tank 113 and the second tank 114 that are partitioned by the partition plate 112, as illustrated in FIG. 1, has been described. Is not limited to this example. The water tank 106 may include, for example, three or more tanks partitioned by two or more partition plates. FIG. 11 includes a first tank 113, a second tank 114, and a third tank 118. The first tank 113 and the second tank 114 are partitioned by a partition plate 112, and the second tank 114 and the third tank 118 are partitioned. An example partitioned by a plate 117 is shown.

In the example of FIG. 11, the first tank 113 is supplied with UFB-containing water from the UFB generator 105, and the second tank 114 and the third tank 118 are the first tank 113 and the second tank 114 to the partition plate 112, respectively. The UFB-containing water is supplied over the upper end of 117. The UFB-containing water stored in the third tank 118 is supplied from the third tank 118 to the pump 102. As a result, since the bubbles floating on the water surface are blocked and disappear by the partition plates 112 and 117 over a plurality of times, the defoaming ability can be improved as compared with the case of using two tanks.
In the example shown in FIG. 11, the water flow forming plate 115 having the opening 116 formed near the bottom is provided inside the first tank 113 and the second tank 114 as in the example shown in FIG. There is.

Further, in the above-described embodiment, the partition plate 112 of the water tank 106 is provided at the upper end of the partition plate 112, as shown in FIG. 12, and is arranged from the first tank 113 on the upstream side to the second tank 114 on the downstream side. An inclined plate 112a that is inclined to the right may be formed. Thereby, when the UFB-containing water is supplied from the first tank 113 to the second tank 114 over the upper end of the partition plate 112, the UFB-containing water flows on the inclined plate 112a. At this time, on the inclined plate 112a, the water flow velocity Va on the side closer to the plate surface becomes slower than the water flow velocity Vb on the side closer to the surface due to the resistance of the plate surface. As a result, the bubbles in the water flow are attracted to the surface side having a high velocity, and the bubbles having a relatively large diameter contained in the water easily come into contact with the air, so that the ability to eliminate the bubbles can be improved.
The partition plate 117 shown in FIG. 11 may also be provided with an inclined plate.

100 Micro Bubble Generation System 102 Pump 103 Pressure Tank 104 First Valve 105 Ultra Fine Bubble Generation Device (UFB Generation Device)
106 water tank 107 circulation pipe 108 second valve 110 cooling water tank 111 cooling coils 112, 117 partition plate 112a inclined plate 113 first tank 114 second tank 115 water flow forming plate 116 opening 118 third tank 119 third valve 120 branch pipe

Claims (8)

A pump which is supplied with a liquid and takes in gas while pressurizing the liquid and transferring a gas-containing liquid,
A pressure tank which stores the gas-containing liquid supplied from the pump, the pressure of which is increased by the pump;
For the gas-containing liquid supplied from the pressure tank and decompressed, an outer casing having an upper part closed on a cylindrical container, a rotor provided inside the outer casing to apply a shearing force, and the rotor is rotated. And a cylindrical inner casing covered by the rotor , wherein the outer casing, the rotor and the inner casing are arranged along a common central axis and contain ultra fine bubbles having a diameter of less than 1 μm. An ultra fine bubble generation device for generating an ultra fine bubble containing liquid,
Equipped with
The ultrafine bubble generation device,
An upstream fluid shear space in which the gas-containing liquid flows between the inner peripheral surface of the rotor and the inner casing,
A downstream fluid shear space in which the gas-containing liquid flows between the outer peripheral surface of the rotor and the inner peripheral surface of the outer casing,
A fluid inlet for flowing the gas-containing liquid in the fluid shear space of the upstream,
A fluid outlet for discharging the fluid from the fluid shear space of the downstream,
A first passage communicating with the fluid inlet portion and formed inside the rotor along the axial center of the rotor;
A second passage communicating with the first passage and formed in the rotor so as to extend in a direction intersecting with the first passage;
Equipped with
The first passage and the second passage are provided between the fluid inlet portion and the upstream fluid shear space in the flow of the fluid,
The fluid shear space on the upstream side has a smaller diameter than the fluid shear space on the downstream side and overlaps with the inner circumferential side of the fluid shear space on the downstream side,
A microbubble generation system , wherein an uneven fluid shearing shape is formed in at least one of the upstream fluid shearing space and the downstream fluid shearing space . A pipe connecting the pressure tank and the ultra fine bubble generator,
A first valve provided in the pipe for adjusting the pressure in the pressure tank;
The microbubble generation system according to claim 1 , further comprising: The microbubbles according to claim 1 or 2 , further comprising a liquid tank that stores the ultrafine bubble-containing liquid supplied from the ultrafine bubble generation device and that supplies the stored ultrafine bubble-containing liquid to the pump. Generation system. The liquid tank includes a first tank and a second tank which are separated from each other by a partition plate, the first tank is supplied with the ultrafine bubble-containing liquid from the ultrafine bubble generating device, and the second tank is The microbubble generation system according to claim 3 , wherein the ultrafine bubble-containing liquid is supplied from the first tank over the upper end of the partition plate. The microbubble generation system according to claim 4 , further comprising an inclined plate provided on an upper end of the partition plate and inclined downward from the first tank to the second tank. The microbubble generation system according to any one of claims 1 to 5 , wherein the motor of the ultrafine bubble generation device has an adjustable rotation speed. The microbubble generation system according to any one of claims 1 to 6 , further comprising a second valve provided in the pump and capable of adjusting an amount of the gas taken in by the pump. The microbubble generation system according to any one of claims 3 to 5 , further comprising a cooling device that cools the liquid containing ultrafine bubbles stored in the liquid tank.

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