JP2003088740A - Bubble generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bubble generator which can generates fine bubbles in a liquid, can improve the cleaning action by extending the dwell time of bubbles in the liquid, has a simple structure, and is prepared and operated at a low cost. SOLUTION: The bubble generator 10 is equipped with a motor 1 and a rotating cylinder 3 directly connected to the rotating shaft 2 of the motor 1. The rotating shaft 2 has an air suction port 4 in the axial direction and has such a structure that air flows to the rotating cylinder 3 communicated with the rotating shaft 2. At the end of the rotating cylinder 3 reverse to the end directly connected to the rotating shaft 2, an air diffusion pipe 5 is set so as to be rotatable together with the rotating cylinder 3. The air diffusion pipe 5 has air diffusion holes 33 for releasing bubbles into a liquid, and the air diffusion holes 33 are formed in the circumferential and axial directions of the air diffusion pipe 5. By rotating the air diffusion pipe 5 together with the rotating cylinder 3, bubbles are released from the air diffusion holes 33 into the liquid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bubble generator, and more particularly to a device for purifying by generating a fine bubble by passing a gas such as air in a liquid.

[0002]

2. Description of the Related Art A system for purifying water is one of the essential techniques for human life, and various techniques have been developed and improved especially with the development of urban life. Also recently
Due to the great interest in environmental issues, purification of sewage and conservation of water quality are positioned as important technologies that lead to the conservation of ecosystems.

As the water system requiring water purification and water quality conservation, for example, drainage derived from industries such as domestic wastewater and industrial wastewater, as well as pond lakes and the sea are targeted.

Wastewater from factories is recognized as one of the causes of environmental problems, especially water pollution. For example, wastewater originating in the textile industry, food industry, chemical industry, etc. needs to be treated with particular care. There is. Examples of the causative substance of water pollution contained in these industrial wastewaters include organic wastes discharged during food processing, coloring components used for coloring fibers, and the like. In addition, since a large amount of industrial water is used in the metal coating industry, a large amount of factory wastewater is discharged. Therefore, these industries require large-scale wastewater treatment facilities.

Domestic wastewater mainly refers to sewage, and these are usually treated collectively in a sewage treatment plant. Due to the development of urban life and increasing environmental awareness, domestic wastewater treatment technology
It is recognized as an important technology for purifying the water quality of water sources and ensuring the safety of drainage.

[0006] As such a water purification / water quality conservation technique, various devices for injecting air into water have been developed as a technique for decomposing and removing organic substances and bacteria in water, and are widely used in wastewater treatment and the like. There is. As a device for generating bubbles in a liquid, various devices such as a device having a relatively simple structure in which air is pumped by a pump and a device for sending air into the liquid by rotating a propeller are put into practical use. ing.

By the way, the purpose of generating bubbles in the liquid is
Dissolving and removing organic substances and bacteria in water by improving the stirring effect due to the generation of bubbles, and improving the dissolved oxygen concentration (DO value) in the liquid to accelerate the decomposition action of organic substances by aerobic bacteria, or The adsorption of contaminants by the bubbles is desirable, but for this purpose, it is desirable that the residence time of the bubbles in the liquid is as long as possible. For that purpose, it is effective to make the bubble diameter as small as possible due to the problem of buoyancy. However, the bubbles generated by the bubble generating device according to the conventional technology are limited to have a diameter of 20 μm to 30 μm at the smallest, and it has been impossible to generate fine bubbles having a diameter smaller than this.

For example, in the case of the propeller rotating type, the number of rotations of the motor must be increased in order to reduce the bubble diameter. Currently, a high-performance motor capable of rotating 10,000 revolutions / minute has been developed, but a large amount of power is required to increase the number of revolutions of the motor due to the resistance of water to the propeller. For this reason, in the actual device, the number of rotations of the motor is currently suppressed to about several thousand rotations / minute, and with the propeller rotation type, small bubbles are generated in the liquid to the extent that sufficient retention time is realized. It was difficult to design a device that could do it.

Further, when air is blown in using a pump, if the hole diameter is reduced to obtain fine bubbles,
Since the pump pressure must be increased and a large amount of power is required, the cost is increased.

[0010] To solve these problems, Japanese Patent Laid-Open No. 2001-2
Japanese Patent No. 25060 proposes the following technique as a method for obtaining fine bubbles. That is, fine bubbles are generated by generating cavitation in water by ultrasonic irradiation. Alternatively, chloride ions are added to the liquid and an electrode plate is placed in the liquid to generate fine bubbles. Here, the fine bubbles are 10 μm in diameter.
It refers to the following bubbles.

However, the technique disclosed in Japanese Patent Laid-Open No. 2001-225060 requires expensive equipment such as an ultrasonic oscillator used for ultrasonic irradiation and an ultrasonic vibrator. Also, the generation of cavitation due to ultrasonic waves is greatly affected by parameters such as the volume and depth of the storage tank that performs ultrasonic irradiation, and the device design must be changed depending on the usage conditions in order to use it as a general-purpose technique. . In addition, because it uses an ultrasonic vibrator, an electrode plate, a chloride ion supply device, etc., it is basically limited to use as a fixed type device, especially if it is suitable for use in pond lakes and the sea, etc. There wasn't. Furthermore, it was not intended to impart impact to organic substances and bacteria by continuous generation of fine bubbles.

[0012]

As described above, as a water treatment technology, there has been a demand for a bubble generating apparatus that generates fine bubbles at a low cost and that limits the type of drainage and the installation location of the apparatus. .

The present invention has been made in consideration of the above circumstances, and it is possible to improve the purifying action by generating fine bubbles in the liquid and prolonging the residence time of the bubbles in the liquid. It is also an object of the present invention to provide a bubble generating device which has a simple structure and which can be manufactured and operated at low cost.

[0014]

In order to solve the above-mentioned problems, the bubble generating apparatus according to the present invention has an intake port formed along the axial direction of the rotating shaft as described in claim 1. A motor for high-speed rotation, one end of which is directly connected to the rotation shaft of the motor in a state of communicating with the intake port of the rotation shaft, and the other end of which is suspended to a predetermined depth in the liquid and rotates integrally with the rotation shaft. It has a rotary cylinder of a length and a peripheral wall of a perfect circular shape which is concentric with the rotary cylinder at the other end of the rotary cylinder and has a large number of small air diffuser holes penetrating the peripheral wall. An air diffuser is provided for discharging gas into the liquid through the air diffuser holes by suction force toward the outer circumference based on the difference in peripheral speed between the inner and outer circumferences of the peripheral wall.

In order to solve the above-mentioned problems, the bubble generating apparatus according to the present invention sets the rotation speed of the rotating shaft to 10,000 rpm or more, as described in claim 2. Further, as described in claim 3, the air diffuser has a diameter of 1 mm or less.

In order to solve the above-mentioned problems, the bubble generating apparatus according to the present invention has a gas blowing device connected to the intake port of the rotating shaft as described in claim 4, or As described in Item 5, the gas is high concentration oxygen or ozone.

In order to solve the above-mentioned problems, the bubble generating apparatus according to the present invention comprises, as described in claim 6, a guide tube for inserting the rotary cylinder inside the rotary cylinder, The liquid retained between the rotary cylinder and the guide tube is caused to function to hold the rotary cylinder.

Further, in order to solve the above-mentioned problems, the bubble generating apparatus according to the present invention, as set forth in claim 7, is an organic matter in liquid due to collision impact of bubbles generated by rotation of the rotating shaft. Or as a liquid purification device for crushing and purifying bacteria, or as described in claim 8,
It is applied as a liquid purification device that ionizes water molecules by cavitation generated in the solution by the rotation of the rotating shaft and decomposes organic substances and bacteria in the liquid.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a plan view showing the structure of the bubble generating apparatus according to this embodiment. As shown in FIG. 1, this bubble generator is used for the liquid surface of the liquid to be purified, for example, the wastewater treatment facility such as a wastewater reservoir of a factory or a water purification plant, or the water surface or the sea surface of a pond or lake that requires water quality conservation. Is installed in.

The bubble generating device 10 is schematically shown as a motor 1.
And a rotary cylinder 3 whose one end is directly connected to the rotary shaft 2 of the motor 1. The motor 1 is installed so that the rotating shaft 2 is perpendicular to the liquid surface. The rotary shaft 2 has an intake port 4 penetrating in the axial direction, that is, the vertical direction.
Communicate with the inside of the rotary cylinder 3. As a result, the rotating shaft 2
The structure is such that air flows in between the rotary cylinder 3 and the rotary cylinder 3. The other end of the rotary cylinder 3 is vertically inserted at a constant depth position in the liquid, and an air diffuser 5 is integrally rotatable at the tip thereof. The details will be described below.

The motor 1 is supported from below by a plate-shaped motor support 6 horizontally provided above the liquid surface, and is fixed by fixing means 6a such as bolts and nuts. The motor support 6 is fixed to a float 7 floating on the liquid surface by fixing means 7a such as bolts.

The float 7 is, for example, an annular member formed of a material having a large buoyancy, and is arranged concentrically with the rotary shaft 2 so as to surround the outer periphery of the motor 1 in this embodiment. Due to the buoyancy of the float 7, the bubble generator 10 is installed in a state of floating on the liquid surface.

The lower end side of the rotary cylinder 3 is inserted into the guide tube 8 and is suspended in the liquid up to a certain depth X which is a bubble generation position in the liquid.

The guide tube 8 is an open tube having an inner diameter larger than the outer diameter of the rotary cylinder 3. The guide tube 8 is a support rod 9
It is held in the liquid by the guide tube flanges 11 and 12. The method of holding the guide tube 8 will be described in detail below.

The support rod 9 is a rod-shaped member, which is fixed to the motor support 6 by fixing means 9a such as bolts and nuts and is suspended in water in parallel with the rotary shaft 3. A plurality of support rods 9 are provided in the circumferential direction of the motor support 6. The support rod 9 is provided with fixing means 9b and 9c such as nuts, and fixes the guide pipe flanges 11 and 12 near the liquid surface and near the lower end of the support rod 9, respectively. The guide tube flanges 11 and 12 insert the guide tube 8 therein, and vertically hold the upper opening 8a of the guide tube 8 so as to project above the liquid surface.

The guide tube 8 is fixed only by the supporting rod 9 and the guide tube flanges 11 and 12, and since the guide tube 8 is not provided with a holding mechanism such as a bearing,
The rotary cylinder 3 and the guide tube 8 do not come into contact with each other at any part.

If the support rod 9 cannot be installed at the same position as the bolt hole positions of the guide pipe flanges 11 and 12, the support rod 6 and the guide rods are guided by using the flange auxiliary plates 11a and 12a as shown in FIG. The pipe flanges 11 and 12 are fixed. The flange auxiliary plates 11a and 12a are plate-shaped members that expand the edge portions of the guide pipe flanges 11 and 12.
In this case, the flange auxiliary plates 11a and 12a are fixed to the support rod 9 by the above-mentioned fixing means 9b and 9c, and the flange auxiliary plates 11a and 12a and the guide pipe flanges 11 and 12 are fixed by fixing means such as bolts 11b and 12b. To be done.

Further, the depth Y of the guide tube 8 suspended in the liquid is set so that the dispersion cylinder 5 projects into the liquid from the lower opening 8b of the guide tube 8. It is configured to be smaller than size X.

Next, the structure of the motor 1 will be described with reference to FIG. The motor 1 is a brushless motor, and the motor 1 is capable of high speed rotation of tens of thousands of revolutions / minute, for example, 30,000 revolutions / minute.

The rotary shaft 2 is rotatably supported by bearings 21 and 22. Bearing 2
The bearings 1 and 22 are fixed to the frame 25 by bearing retainers 23a and 23b and a nut 24.

The frame 25 is a cover member which is composed of a plurality of members and constitutes the main body of the motor 1, and a cylindrical cavity 26 is provided in the frame 25. The rotary shaft 2 is inserted into the cavity 26, and a magnet 27 as a rotor provided on the outer peripheral portion of the rotary shaft 2, a stator 28 surrounding the magnet 27, and a spacer 29 are housed. The rotating shaft 2 is rotated at a high speed in the cavity 29 in the frame 25. The bearings 21 and 22 are the only parts where the rotary shaft 2 mechanically contacts.

A flange portion 30 is provided on the connection side of the rotary shaft 2 with the rotary cylinder 3, that is, on the lower portion of the rotary shaft 2, and the rotary shaft 2 and the rotary cylinder 3 have a flange portion 30 and a rotary cylinder connecting flange. 31 is connected by being fixed by a fixing means such as a bolt nut 31a. Air is taken in from the intake port 4 by driving the motor 1, and the air flows to the rotary cylinder 3 and the air diffuser pipe 5 provided at the tip of the rotary cylinder 3.

Next, the structure of the air diffuser 5 will be described with reference to FIG.

FIG. 3 shows the structure of the air diffuser 5. Air diffuser 5
Is a circular tube having a constant thickness and a short axis and one end opened, and the bottom of the air diffusing tube 5 is closed for the purpose of discharging bubbles from the air diffusing holes 33. The open end of the air diffuser 5 is fixed to the lower end of the rotary cylinder 3 by a fixing method such as welding or screwing. The air diffuser 5 has a peripheral wall 32 having a true circular cross section that is concentric with the rotary cylinder 3, and the peripheral wall 32 is provided with a large number of air diffuser holes 33 that are pores for discharging bubbles into the liquid. And are arranged in a precise arrangement in the axial direction.

By driving the motor 1, the air diffusing tube 5 horizontally rotates in the liquid around the vertical axis. During this rotation,
Since the outer peripheral surface of the air diffuser 5 has a perfect circular cross section, water resistance hardly occurs, and the air diffuser 5 smoothly rotates in a non-resistance state. Therefore,
High-efficiency rotation is achieved without causing the wave like when the screw is rotating. When the air diffuser 5 rotates integrally with the rotary cylinder 3, a peripheral speed difference is generated between the inside and the outside of the peripheral wall 32 of the air diffuser 5, and bubbles are discharged into the liquid from the air diffuser 33. In FIG. 3, the arrow indicates the air flow direction.

When the liquid is purified by the bubble generating apparatus shown in FIG. 1, first, the motor 1 is driven and the rotary shaft 2 is rotated, so that the rotary cylinder 3 and the air diffusing pipe 5 are caused by the rotation of the rotary shaft 3. Rotate together. In the air diffuser 5, the inflowing air is discharged into the liquid as fine bubbles due to the peripheral speed difference between the inner wall and the outer wall of the peripheral wall 32. Therefore, the pressure inside the rotary cylinder 3 is always negative while the motor 1 is being driven, and the outside air continuously flows in through the intake port 4, so that bubbles are continuously discharged into the liquid.

A mechanism by which the rotary cylinder 3 of the bubble generating apparatus according to the present invention rotates stably will be described with reference to FIG.

Usually, when the rotating shaft is rotated at a high speed of 10,000 rpm or more, the rotating shaft is shaken. Therefore, unless the end of the rotating shaft is fixed with a bearing, stable rotation cannot be obtained. However, since it is difficult to install a normal bearing underwater, it has been a bottleneck in designing a water purification device.

However, in the bubble generating apparatus according to the present invention, the rotary cylinder 3 does not need to be fixed by a fixing means such as a bearing other than connecting to the rotary shaft 2 of the motor 1. By providing the guide tube 8, an air layer 41 and a liquid layer 42 are formed between the rotary cylinder 3 and the guide tube 8 as shown in FIG. 4, and this phenomenon causes the liquid layer 42 to serve as a bearing. This is because it functions and the rotary cylinder 3 is stably held. According to the implementation of the present inventors, the rotary cylinder 3 and the guide tube 8
The distance between and is preferably about 10 mm, and a good holding action for the rotary cylinder 3 can be obtained.

The guide tube 8 may be made of an inexpensive material, such as a polyvinyl resin tube, does not require any mechanical elements such as bearings other than the motor 1, and has a simple device structure, so that the manufacturing cost can be kept low. Not only is it possible, but because there is no contact part, the consumption of parts is small,
It is economical.

The mechanism for holding the rotating shaft by installing the guide tube shown in the bubble generating apparatus according to the present invention is not limited to the application to the water treatment device, but can be widely applied to devices that rotate the shaft in liquid. It is a mechanism that can.

Experimental examples of the bubble generator according to the present invention will be described below.

The present inventors manufactured the bubble generator shown in FIG. 1 and examined the bubble generation state and bubble diameter.

Air diffuser holes 33 are provided in the peripheral wall 32 of the air diffuser pipe 5. The diffuser holes had a diameter of 0.5 mm, and 10 diffusers were provided in the circumferential direction of the diffuser tube 5, and 20 rows were provided in the axial direction. The air diffuser 5 was attached to the tip of the rotary cylinder 3 so that the lower surface of the air diffuser 5 was installed at a water depth of 655 mm, and was suspended in water.

Next, the motor 1 is driven and the number of revolutions is 30,000.
When rotated at a speed of rotation / minute, bubbles were generated in the liquid as described below.

[0047]

[Equation 1] 30000 revolutions / minute × 10 pieces / 60 = 5 kHz

When the diameter of the bubble generated at this time was measured, it was found that the diameter of the bubble was 10 μm or less, and that the generation of extremely fine bubbles was 20 to 30 μm as compared with the bubble diameter of 20 to 30 μm which can be generated by the conventional bubble generator. Was confirmed to be possible.

The fine air bubbles of 10 μm or less generated in this experimental example have a long residence time in the liquid, and as a result, the dissolved amount of air in the liquid is increased, so that the dissolved oxygen amount can be improved. .

Further, in the present experimental example, since bubbles are generated at a high frequency of 5 kHz, impacts due to the collision of bubbles on organic substances and bacteria in the liquid are continuously repeated, and organic substances and bacteria are destroyed by the collision pressure of the bubbles. Since it is pulverized and removed, it has a high purification effect.

According to the study by the present inventors, the diameter of the air diffuser 33 is preferably 1.0 mm or less, and particularly 0.5 m.
What is provided in m is capable of generating fine bubbles of 10 μm or less under the operating conditions of the rotation speed of the motor 1 of 30,000 rotations / minute.

Further, it was confirmed that the operating load of the motor 1 in the present experimental example is about 400 to 500 W, and the electric power cost related to the operation can be suppressed.

Further, according to the bubble generating apparatus of the present invention, the high speed rotation of the motor 1 causes cavitation in the liquid. An ultrasonic oscillator is known as a device for decomposing stains to which cavitation is applied, but cavitation generated by the bubble generating device according to the present invention has an impact effect on organic substances and bacteria, like cavitation by an ultrasonic oscillator. , With the effect of purifying water quality.

Although this cavitation does not occur when the number of rotations of the motor is about several thousand revolutions, the bubble generating apparatus according to the present invention realizes high-speed rotation of 10,000 revolutions / minute or more, so that it is easy to generate cavitation.

Further, since the cavitation generation by the bubble generating device according to the present invention is a simple mechanism by the rotation of the motor 1, the device structure is simple and the device manufacturing cost and running cost are higher than those of the ultrasonic oscillator. Is low.

It is known that some water molecules are separated into hydrogen ions and hydroxide ions by the occurrence of cavitation. Organic compounds and bacteria are decomposed by the ionized water molecules. That is, in the bubble generating apparatus according to the present invention, in addition to the effect of continuous collision of bubbles, the effect of decomposing organic substances by cavitation is also provided, so that the water purification action is further improved.

Another embodiment of the bubble generating apparatus according to the present invention will be described with reference to FIG.

The embodiment of the bubble generator shown in FIG. 5 is an embodiment in which gas is blown into the liquid by using the gas supply device 50 instead of air.

In the present embodiment, the intake port 4 of the bubble generating device
To the gas supply cable 5 via the coupling device 51.
2 is connected to the gas supply device 50. The coupling device 51 is configured so that the gas supply cable 52 does not rotate integrally with the rotating shaft 2. The gas supply cable 52 is composed of a steel pipe, copper tubing, or a flexible resin pipe.

According to the bubble generating apparatus of this embodiment, it is possible to blow in a gas other than air, which is effective for purifying water.

As such a gas, for example, high-concentration oxygen or ozone can be used instead of air. Air is composed of about 20% oxygen and 80% nitrogen, and nitrogen is also considered to be a cause of eutrophication of water and a cause of water pollution such as red tide. Therefore, by supplying high-concentration oxygen instead of air, it is possible to improve the dissolved oxygen concentration in the liquid, avoid the problem of eutrophication, more effectively decompose organic substances and bacteria, and purify water. it can.

Further, ozone has a high sterilizing effect, and the use of ozone as a blowing gas enhances the effect of sterilizing bacteria in the liquid. Therefore, the bubble generating apparatus according to the present invention can be used as a more effective water purifying apparatus. Can be used.

[0063]

As described above, according to the bubble generating apparatus of the present invention, since fine bubbles are generated in the liquid by the high speed rotating diffusing pipe, the residence time of the bubbles in the liquid is lengthened. It is possible, and as a result, the amount of air dissolved in the liquid is improved, so that the purification action can be improved.

Further, according to the bubble generating apparatus of the present invention, since high-frequency fine bubbles are emitted into the liquid, impact force is applied to organic substances and bacteria by continuous collision of the fine bubbles. Organic substances and bacteria inside are pulverized and removed, and a high purification action can be obtained.

Further, according to the bubble generating apparatus of the present invention, since cavitation is generated in water, the impact of cavitation and the action of water molecules ionized by the generation of cavitation cause organic substances and bacteria in the liquid to be removed. Since it is decomposed, the purifying action can be improved.

Further, according to the bubble generating apparatus of the present invention, the rotary shaft of the motor is provided with the intake port along the axial direction, and the air is circulated in the liquid through the rotary shaft.
A device such as a pump for circulating air in the liquid is not required, the device structure can be simplified, and a high purification action can be obtained while keeping the manufacturing cost and running cost low.

Further, according to the bubble generating apparatus of the present invention, since the guide tube is provided on the outer periphery of the rotary cylinder,
Since the rotary cylinder is stably held by the action of the liquid layer and the air layer generated in the space between the rotary cylinder and the guide tube due to the high-speed rotation of the rotary cylinder, a holding mechanism such as a bearing is not required in the guide tube. Fine bubbles can be generated in the device structure, and a high purification action can be obtained at low cost.

Further, a structure in which a gas supply device is connected to the intake port of the motor rotating shaft and a gas such as high-concentration oxygen or ozone is blown in is an organic substance due to aerobic bacteria by increasing the dissolved oxygen concentration in the liquid. Promotes the decomposition of
Or because the sterilization effect by ozone can be obtained,
Further, the purifying action can be improved.

[Brief description of drawings]

FIG. 1 is a plan view showing the overall configuration of an air bubble generating device according to the present invention.

FIG. 2 is a cross-sectional view showing the structure of a motor of a bubble generating device according to the present invention.

FIG. 3 is a cross-sectional view showing the structure of an air diffusing tube of the bubble generating device according to the present invention.

FIG. 4 is an explanatory view illustrating a mechanism in which a rotary cylinder of the bubble generating device according to the present invention stably rotates.

FIG. 5 is a plan view showing another embodiment of the bubble generating device according to the present invention.

[Explanation of symbols]

1 motor 2 rotation axes 3 rotating cylinder 4 air intake 5 Air diffuser 6 motor support 7 floats 8 guide tubes 9 Support rod 10 Bubble generator 11 Guide tube flange (upper side) 12 Guide pipe flange (lower side) 21 Bearing (upper side) 22 Bearing (lower side) 23 Bearing suppression 24 nuts 25 frames 26 cavities 27 magnets 28 Stator 29 Spacer 30 Flange 31 Flange for connecting rotating cylinder 32 scattered cylinders 33 air diffuser 41 Air layer 42 liquid layer 50 gas supply device 51 Coupling device 52 gas supply cable

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C02F 1/50 531 C02F 1/50 531R 540 540A 550 550C 560 560C ZAB ZAB 1/78 1/78 3/20 3/20 DF term (reference) 4D029 AA01 AB02 BB11 CC03 4D037 AA05 AA06 AA11 AB01 AB03 BA26 BB05 CA12 4D050 AA06 AA13 AB06 AB07 BB01 BB02 BD03 CA20 4G035 AB17 AE13 4G037 AA01 EA10

Claims (8)

[Claims] 1. A motor for ultra-high speed rotation, which has an intake port formed along the axial direction of a rotary shaft, and a rotary shaft of the motor, one end of which is directly connected to the intake port of the rotary shaft and the other end of which is directly connected. Is a rotary cylinder of a certain length that is suspended to a predetermined depth in the liquid and integrally rotates with the rotary shaft, and is integrally rotatably provided at the other end of the rotary cylinder, and has a perfect circular cross section concentric with the rotary cylinder. And has a large number of small diameter diffuser holes penetrating the peripheral wall, and the gas is released into the liquid through the diffuser holes by the suction force to the outer peripheral side based on the peripheral speed difference between the inner and outer circumferences of the peripheral wall. An air bubble generator comprising an air diffuser. 2. The rotation speed of the rotary shaft is 10,000 per minute.
The bubble generating device according to claim 1, wherein the bubble generating device is set to rotate or more. 3. The bubble generator according to claim 1, wherein the air diffuser has a diameter of 1 mm or less. 4. The bubble generating device according to claim 1, wherein a gas blowing device is connected to an intake port of the rotary shaft. 5. The bubble generator according to claim 4, wherein the gas is high-concentration oxygen or ozone. 6. A guide tube into which the rotary cylinder is inserted is provided on the outer side of the rotary cylinder, and liquid retained between the rotary cylinder and the guide tube is caused to function for holding the rotary cylinder. 6. The bubble generator according to any one of 1 to 5. 7. The bubble according to any one of claims 1 to 6, which is applied as a liquid purifying apparatus for crushing and purifying organic substances and bacteria in a liquid by collision impact of bubbles generated by rotation of the rotating shaft. Generator. 8. The liquid purification device according to claim 1, wherein the liquid purification device is configured to ionize water molecules by cavitation generated in a solution by rotation of the rotating shaft to decompose organic substances and bacteria in the liquid. Bubble generator.