JPH057752A - Apparatus for stirring and mixing liquid and air - Google Patents

Abstract

PURPOSE:To enhance the generation efficiency of air bubbles in a stirring and mixing device rotating the driving body in an outer shell body under water surface at a high speed to dissolve air in water. CONSTITUTION:In an apparatus wherein a linear columnar driving body 1 is inserted in and attached to a linear cylindrical outer shell body 2 whose upper end opening part 4 opened to the air is arranged so as to protrude from the surface of the water and the gap 7 between the outer shell body 2 and the driving body 1 is set to as small a value as possible within such a range that water can invade in the gap 7 at the time of the high speed rotation of the driving body 1 to be positioned within the gap 7, the driving body 1 is rotated at a peripheral speed of 10-20m/s within such a range that centrifugal force acts on the water invading in the gap 7 to be positioned therein. When the peripheral speed is lower than said speed, air bubbles become coarse and, when the peripheral speed is higher than said speed, sliding is generated between the outer peripheral surface of the driving body 1 and water, thus the generation efficiency of air bubbles is lowered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stirrer for mixing a liquid and a gas so that the gas can be more efficiently dissolved in the liquid.

[0002]

2. Description of the Related Art When a gas such as air is supplied into a liquid such as water in the form of bubbles and the gas is to be dissolved in the liquid, if the bubbles are large, the buoyancy causes the liquid to reach the liquid surface in a short time. Since air bubbles cannot float in the liquid for a sufficient time for the gas to dissolve in the liquid because it floats, extremely small bubbles in the liquid are generated by violently swirling the liquid in the gas atmosphere. A mixing and stirring apparatus for a liquid and a gas has been proposed in which the gas and the gas are efficiently dissolved in the liquid by generating a large number of bubbles in the liquid for a long time. (See Japanese Patent Publication No. 61-36448).

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The apparatus disclosed in Japanese Patent No. 448 has a linear cylindrical outer shell body in which an upper end opening opening in a gas atmosphere to be mixed is arranged so as to project above the liquid surface to be mixed, and the outer shell. It consists of a linear cylindrical or linear cylindrical driving body that is inserted and assembled coaxially over the entire length of the body and is driven to rotate at a high speed, and drives the gap between the outer shell and the driving body. The liquid is set to a value as small as possible within the range where the liquid can enter the gap during high-speed rotation of the body, and the rotational speed of the drive body rotated at a high speed is 7,000 rpm or more. Furthermore 8000
It is said that rpm or more is desirable.

By the way, the stirring and mixing of the liquid and the gas in such a device is based on the viscosity of the liquid and the gas. However, according to the experiments confirmed by the inventors, extremely small bubbles are found in the liquid. It was found that the peripheral speed of the driving body has an appropriate range for efficient generation. That is, the present invention is a further development of the technique disclosed in Japanese Patent Publication No. 61-36448, and in particular, a liquid and a gas capable of efficiently generating extremely small air bubbles in water. The object is to provide a stirring and mixing device.

[0005]

In order to achieve the above-mentioned object, the present invention has the above-mentioned structure at a peripheral speed within a range in which a centrifugal force acts on a liquid located in a gap between an outer shell and a driving body. The drive shall be rotated. In particular, when water and air are stirred and mixed, the peripheral speed of the driving body is 10 to 20 m /
Set to s. A diffuser plate is provided at the lower end of the drive body to radiate the liquid containing bubbles discharged downward from the lower end opening of the outer shell obliquely upward or downward depending on the depth of the liquid. Is good.

[0006]

The liquid containing bubbles is discharged downward from the lower end opening of the outer shell when the driving body is rotationally driven at high speed in the outer shell. This is due to the action of moving and entraining the gas in a violent vortex and pushing it out from the lower end opening of the outer shell by centrifugal force. Since such a motion of the liquid is caused by the liquid rotating with the outer peripheral surface of the driving body due to its viscosity, it is desirable that the peripheral speed of the driving body is as high as possible in order to give sufficient motion to the liquid. . In particular, since the subdivision of bubbles is performed by the vortex motion, it is necessary to make the vortex motion extremely intense in order to make the bubbles extremely fine.

On the other hand, it is necessary to finish the outer peripheral surface of the driving body to be an extremely smooth surface. If the outer peripheral surface is not smooth, the driving body will vibrate due to friction with the liquid, and the bubbles will be made into desired fine particles. It will not be possible to increase the peripheral speed until it is divided into two. However, it was found that the bubble generation efficiency decreases at a certain stage when the peripheral speed of the driving body whose outer peripheral surface is extremely smooth is gradually increased in the course of the experiment. Considering this phenomenon, the reason is that when the peripheral speed of the driving body becomes too high, slippage occurs between the smooth outer peripheral surface and the liquid, so that the liquid does not rotate easily and the centrifugal force decreases. It has been found.

That is, the peripheral speed of the driving body has an appropriate range according to the viscosity of the liquid. If the peripheral speed is too low, the bubbles become coarse, and conversely if the peripheral speed is too high, the power of the drive motor increases. This causes a phenomenon that the amount of bubbles generated is rather reduced. According to experiments, in the case of stirring and mixing water and air, the peripheral speed suitable for efficiently generating bubbles having a diameter of 10 ⁻⁵ mm or less was 10 to 20 m / s. Therefore, the rotation speed of the driving body must be determined based on the outer diameter of the driving body and an appropriate value of the peripheral speed according to the viscosity of the liquid.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a partial vertical sectional front view of a stirring and mixing apparatus of water and air showing an embodiment of the present invention. In the figure,
The stirring and mixing device is composed of a linear cylindrical outer shell body 2 and a linear cylindrical drive body 1. The outer shell 2 is fixed at its upper end to a base plate 9 immovably arranged immediately above the water surface in a state where the upper end opening 4 of its cylindrical wall 3 is not closed, and is opened in an air atmosphere to be stirred and mixed. The part 4 is arranged so as to project above the water surface where it is agitated and mixed.
A window hole 6 is opened in the upper part of the cylindrical wall 3 in water, and the lower end opening 5 is opened in water. A net 6a is stretched to prevent dust from entering the window hole 6. A mounting plate 10 is fixed on the base plate 9 with a certain space therebetween, and a motor 11 as a drive source is fixed to the mounting plate 10.

Further, the driving body 1 has a length larger than that of the outer shell body 2 described above and has a structure in which the outer peripheral surface thereof is extremely smooth, and is inserted into the outer shell body 2 coaxially. It is assembled. The gap 7 formed between the outer shell 2 and the driving body 1 is set to a value as small as possible within a range where water can enter the gap 7 when the driving body 1 rotates at high speed. There is. The driving body 1 is configured such that a bearing body 14 fixed to a mounting plate 10 on which a motor 11 is mounted firmly holds an upper portion extending upward, and can rotate at high speed in a stable state. . A pulley 12 is fixed to the portion of the driving body 1 located between the base plate 9 and the mounting plate 10, and is fixed to the shaft of the motor 11 and positioned between the base plate 9 and the mounting plate 10. A transmission belt is stretched between the driving pulley 1 and the driving pulley 13, and the driving body 1 is rotationally driven at a peripheral speed of 10 to 20 m / s.

Water mixed with air is discharged from the lower end opening 5 of the outer shell body 2 as will be described later. However, in order to disperse this water in a wide range in the water, the water is mixed in the lower end portion of the driving body 1. A disk-shaped diffuser plate 8 is attached. This diffusion plate 8 forms a radial water flow in the water immediately below the lower end opening 5 of the outer shell 2 as the drive body 1 rotates at high speed. The water mixed with the air discharged from the lower end opening 5 of the outer shell 2 can ride on this water flow and be dispersed in all directions.

In such a structure, in the gap 7 formed between the outer shell 2 and the driving body 1, the window hole 6 of the cylindrical wall 3 of the outer shell 2 and the lower end of the outer shell 2 are formed. Water enters the opening 5 and the upper opening 4 of the outer shell 2 is always open, so that air is supplied from the upper opening 4. From this state, drive unit 1
When rotated at a peripheral speed of ˜20 m / s, water and air in the gap 7 contacting the outer peripheral surface of the driving body 1 rotate due to its viscosity, following the rotational movement of the driving body 1 and causing a violent vortex motion. Further, the centrifugal force causes the pressure in the vicinity of the inner peripheral surface of the outer shell 2 to rise and move downward. The air drawn into the water by the swirling motion is vigorously stirred and subdivided into water by the high-speed rotating operation of the driving body 1 and the vigorous swirling motion of the water, and is formed into extremely fine bubbles. Then, the bubbles are vigorously discharged downward from the lower end opening 5 of the outer shell 2 together with the water that vigorously swirls, and are further dispersed on the water flow in the radial direction by the diffusion plate 8 to a long distance.

The air and water in the gap 7 are discharged to the outside from the lower end opening 5 of the outer shell 2 by the high speed rotation operation of the driving body 1, so that the water level in the gap 7 is lowered. Since the window hole 6 is opened in the cylindrical wall 3 of the outer shell body 2 just below the water surface, water is always supplied to the inside of the gap 7 through the window hole 6, and therefore the inside of the gap 7 is The water level never drops below this window 6. In the illustrated embodiment, the drive body 1 is rotated via the transmission belt between the pulleys 12 and 13, but it is also possible to drive the drive body 1 by directly connecting it to the motor shaft.

2 (A) to 2 (C) respectively show a diffusion plate 8.
2 shows another embodiment of the present invention. The disc-shaped diffuser plate 8 of FIG. 1 has an outer diameter smaller than the inner diameter of the outer shell body 2, and the water discharged downward from the lower end opening 5 of the outer shell body 2 is slightly a little as shown by an arrow in FIG. Emitted downward. In (A), the diffusion plate 8 is in the shape of a dish that is convex upward, and the water that is diffused is further downward and bubbles are dispersed to a deep portion in the water. Such a diffusion plate 8 is suitable when the water depth is deeper than the underwater length of the driving body 1. On the other hand, (B) shows the diffuser plate 8 having a concave dish shape, and (C) shows a disk shape having an outer diameter larger than the inner diameter of the outer shell body 2. As shown in the figure, the water containing bubbles is released diagonally upward and the bubbles are dispersed near the water surface.
Such a diffuser plate 8 is suitable when the outer shell 2 opens at the bottom of the water tank.

[0015]

The present invention pays attention to the peripheral speed of the driving body, and experimentally finds that the desired air bubbles cannot be efficiently obtained even if the peripheral speed is too low or too high. When air is dissolved in water, the peripheral speed of the driving body is 10-2.
By setting it to 0 m / s, it is possible to efficiently generate extremely fine bubbles regardless of the outer diameter of the driving body.

[Brief description of drawings]

FIG. 1 is a partial vertical sectional front view showing an embodiment of the present invention.

2A to 2C are vertical cross-sectional views showing different embodiments of the diffusion plate.

[Explanation of symbols]

1 driver 2 outer shell 7 Gap 8 diffuser

Claims (3)

[Claims] 1. A linear cylindrical outer shell body having an upper end opening opened in a mixed gas atmosphere and projecting above the liquid surface to be mixed, and coaxial with the entire length of the outer shell body. It is composed of a linear cylindrical shape or a linear cylindrical shape driving body that is inserted and assembled on the core and is driven to rotate at a high speed, and a gap between the outer shell body and the driving body is provided when the driving body rotates at a high speed. Within the gap between the outer shell and the driver, in the stirring and mixing apparatus for liquid and gas, which is set to the smallest possible value within the range where the liquid can enter the gap. A stirring device for mixing liquid and gas, wherein the driving body is rotated at a peripheral speed in a range where centrifugal force acts on the liquid. 2. When water and air are mixed by stirring,
The liquid / gas stirring and mixing apparatus according to claim 1, wherein the peripheral speed of the driving body is set to 10 to 20 m / s. 3. A diffuser plate for radiating a liquid containing bubbles discharged downward from the lower end opening of the outer shell in an obliquely upward or obliquely downward direction is provided at the lower end of the driving body. The agitating and mixing apparatus for liquid and gas according to claim 1 or 2.