JP7086435B2 - Micro bubble generation unit and water purification system - Google Patents

Description

The present invention relates to an apparatus for generating microbubbles.

In recent years, paying attention to the fact that microbubbles have a property of adhering and floating pollutants in a liquid, attempts have been made to attach pollutants to the microbubbles and levitate them to purify contaminated water. Microbubbles are fine bubbles having a diameter of 0.5 mm or less, and are also called radical bubbles.
In order to efficiently adhere pollutants to microbubbles, it is effective to flow contaminated water directly into the microbubble generator and generate microbubbles from the contaminated water, so microbubbles are generated in the liquid. Various devices have been proposed (see, for example, Patent Document 1).

The gas-liquid dissolving and mixing device of Patent Document 1 sucks a gas downstream of the throat of the Venturi tube to generate bubbles in a mixer having a Venturi tube, and creates bubbles in a conduit connected to the downstream of the mixer. The liquid and bubbles reach the redistribution device while being dissolved in the liquid, the liquid and bubbles are reaccelerated by the Venturi tube provided in the redistribution device, and the microbubbles are mixed from the nozzle port provided downstream of the redistribution device. The spout is jetted.
However, in a microbubble generator that mixes a liquid and a gas, such as the device of Patent Document 1, the supply path for supplying the gas to the mixer is generally on the wall surface defining the flow path of the liquid in the mixer. , Formed by drilling holes orthogonal to the flow of liquid. Therefore, when the contaminated water is directly flowed into the microbubble generator, the contaminated substance is clogged especially near the outlet of the supply path for supplying the gas, and the microbubble generator cannot be used immediately.

Therefore, the present inventors have already proposed a fine bubble generator in which the outlet end of the gas supply path for supplying gas opens toward the downstream side of the liquid flow (see Patent Document 2).
The fine bubble generator disclosed in Patent Document 2 includes a gas supply path formed as an L-shaped tube, and the outlet end of the gas supply path is formed in the horizontal portion of the L-shaped tube. Is arranged in parallel with the flow of the liquid to prevent the backflow of the gas. Further, in Patent Document 2, the gas supply path is formed as a hole on the wall surface defining the liquid inflow path so that the outlet end faces the downstream side of the liquid flow with respect to the fine bubble generator. The configuration is also disclosed. According to such a configuration, it is not necessary to form an L-shaped tube, and it is possible to facilitate the manufacture of a fine bubble generator.

Special Fair 6-9391 Japanese Patent No. 6104399

However, in the fine bubble generator disclosed in Patent Document 2, the hole provided as the liquid inflow path is only a hole having a shape such that the outlet end faces the downstream side of the liquid flow, and is specific. Sufficient disclosure was not made regarding the degree of inclination and other structures. Further, it can be said that it is preferable that the apparatus can be manufactured at low cost.

In view of such a situation, it is an object of the present invention to provide a microbubble generation unit and a water purification system that can effectively generate microbubbles while preventing backflow of gas and can be produced at low cost. ..

In order to solve the above problems, the microbubble generation unit of the present invention includes an inflow pipe portion into which a pressurized liquid flows in, a discharge pipe portion in which a liquid containing microbubbles is discharged, and an inflow pipe portion and a discharge pipe portion. A hole located between the throat, which has a smaller pipe cross-sectional area than the inflow pipe and the discharge pipe, and the wall surface of the throat or the discharge pipe, which allows gas to be mixed into the throat or the pipe, and is a liquid. The gas mixing hole is provided so that the angle between the flow direction of the gas and the mixing direction of the gas intersects at a sharp angle.
The gas mixing hole is provided so that the angle between the liquid flow direction and the gas mixing direction intersects at an acute angle, so that the outlet end of the gas mixing hole for mixing the gas is located on the downstream side of the liquid flow. It will open facing you. That is, the gas mixing hole has a structure in which it is difficult for the liquid to enter the gas mixing hole unless the liquid flows backward. By having this configuration, it becomes difficult for the liquid to flow into the gas mixing hole in the normal flow of the liquid. As a result, even if contaminated water containing a contaminated substance is introduced as a liquid, the contaminated substance does not enter the gas mixing hole, and it is possible to prevent the gas mixing hole from being clogged. As a result, even if the contaminated water is poured directly into the microbubble generation unit, the microbubbles can be generated from the contaminated water.

In the microbubble generation unit of the present invention, the inner diameter of the throat portion is formed in a stepped shape of at least two steps so that the liquid inflow pipe portion side is narrower and the discharge pipe portion side is wider, and the outlet end of the gas mixing hole is formed. It is preferable that the inner diameter of the throat is formed in a step other than the narrowest step.
With respect to the inner diameter of the throat, the static pressure generated in the throat can be different by forming at least two steps so that the liquid inflow pipe side is narrower and the discharge pipe side is wider. Then, by providing the outlet end of the gas mixing hole in a step other than the narrowest step of the inner diameter of the throat, the liquid having the lowest pressure in the step having the narrowest inner diameter of the throat became higher pressure thereafter. It can be mixed with a gas at the stage and can promote the dissolution of the gas.

In the microbubble generation unit of the present invention, it is preferable that the inner diameter of the throat portion is formed in a three-step step shape that expands toward the discharge pipe portion side. The process of forming in a step shape can be performed at a lower cost than the process of forming in a tapered shape. Therefore, by forming the inner diameter of the throat in a three-step step shape that expands toward the discharge pipe side, the static pressure of the throat gradually increases from the upstream to the downstream, while having a sufficient effect. , It can be configured to suppress the processing cost.

In the micro-bubble generation unit of the present invention, it is preferable that the outlet end of the gas mixing hole is provided at the position of the middle stage of the three stages. By providing the outlet end of the gas mixing hole at the position of the middle of the three stages, the liquid flowing from the inflow pipe portion became higher pressure after the static pressure became the lowest in the front stage of the throat. It can be mixed with a gas in the state, and the dissolution of the liquid and the gas is promoted.

In the microbubble generation unit of the present invention, the angle between the flow direction of the liquid and the mixing direction of the gas is preferably in the range of 60 to 80 °, more preferably 70 to 78 °, and further preferably 70 °. It is 75 °. The angle at which the gas mixing hole is provided is within the above range. If it exceeds 80 °, backflow of gas or clogging of pollutants is likely to occur, and if it is less than 60 °, the difficulty of processing increases and it is manufactured. This is because the cost is high.

It is preferable that the microbubble generation unit of the present invention is provided with a check valve at the inlet end of the gas mixing hole. The check valve is required when adjusting the pressure and shutting off the power supply because the suction pressure changes to the output pressure when the in and out pressures are equal. Therefore, by providing the check valve, it is possible to more effectively prevent the backflow of gas.

The water purification system of the present invention includes the microbubble generation unit described in any of the above, a contaminated water tank that supplies contaminated water to the inflow pipe portion of the unit, and a liquid containing microbubbles discharged from the discharge pipe portion of the unit. It is equipped with a septic tank that floats and separates.
In the water purification system of the present invention, since the microbubble generation unit can generate microbubbles from the contaminated water, the contaminated water (liquid) flowing out from the contaminated water tank is directly flowed into the microbubble generation unit and discharged from the microbubble generation unit. It is possible to adopt a configuration in which the microbubbles to be generated flow into the septic tank.

According to the microbubble generation unit and the water purification system of the present invention, there is an effect that microbubbles can be effectively generated and can be produced at low cost while preventing backflow of gas.

Cross-sectional image of the microbubble generation unit of Example 1 System configuration diagram of the water purification system of Example 1 Cross-sectional image of the microbubble generation unit of Example 2

Hereinafter, an example of the embodiment of the present invention will be described in detail with reference to the drawings. The scope of the present invention is not limited to the following examples and illustrated examples, and many changes and modifications can be made.

FIG. 1 shows a cross-sectional image of the microbubble generation unit of the first embodiment. As shown in FIG. 1, the microbubble generation unit 1 includes an inflow pipe portion 21 into which a pressurized liquid flows in, a discharge pipe portion 23 for discharging the generated microbubbles, and an inflow pipe portion 21 and a discharge pipe portion 23. Consists of a throat 22 connecting to. The inflow pipe portion 21, the throat portion 22, and the discharge pipe portion 23 are connected in order to form a flow path for the liquid flowing from the inflow pipe portion 21. The throat portion 22 is provided with a gas mixing hole 3.

The inflow pipe portion 21 is formed of a tubular portion 21a having the largest diameter and a conical base portion 21b whose diameter gradually decreases toward the throat portion 22 side. Further, the discharge pipe portion 23 is formed of a conical base portion 23b whose diameter gradually increases from the throat portion 22 and a tubular portion 23a having a large diameter thereof. As for the specific diameter, when the diameter R1 of the cylindrical portion 21a is ₁ , the diameter _R2 of the tubular portion 23a is 0.75. The reason why the diameter _R2 of the tubular portion 23a is smaller than the diameter _R1 of the tubular portion 21a is to moderate the opening pressure.

The throat portion 22 is composed of a throat front stage 22a, a throat middle stage 22b, and a throat rear stage 22c, and is provided so that the diameter gradually increases from the throat front stage 22a to the throat middle stage 22b and the throat rear stage 22c. There is.
The front throat 22a, the middle throat 22b, and the rear throat 22c all have a tubular shape having a smaller diameter than the inflow pipe 21 and the discharge pipe 23, and the pipe cross-sectional area is the inflow pipe 21 and the discharge pipe 21 and the discharge. It is smaller than the pipe portion 23. Specifically, when the diameter R ₁ of the tubular portion 21a is 1, the diameter R ₃ of the throat front stage 22a is 0.33, the diameter R ₄ of the throat middle stage 22b is 0.42, and the throat rear stage 22c. The diameter R ₅ of is 0.5. The reason why the throat portion 22 is provided so as to gradually increase in diameter is to gradually increase the static pressure of the liquid flowing into the throat portion 22, and the throat portion 22 is not tapered but has a stepped shape. By providing it, it is possible to process it at low cost.

A male screw portion 4a is provided at the end of the inflow pipe portion 21 opposite to the throat portion 22, and a male screw portion 4b is provided at the end of the discharge pipe portion 23 opposite to the throat portion 22. It can be connected to a joint or the like having a female screw portion. Unlike the above configuration, for example, a female screw portion may be provided on the inner wall of at least one end of the inflow pipe portion 21 and the discharge pipe portion 23.

The gas mixing hole 3 is provided so that the angle between the liquid flow direction and the gas mixing direction intersects at an acute angle. That is, the gas mixing hole 3 is formed on the wall surface defining the middle stage 22b of the throat as a hole having a shape such that the outlet end 3b faces the downstream side of the liquid flow with respect to the microbubble generation unit 1. Here, the angle θ indicates the angle of the gas mixing hole 3 with respect to the direction perpendicular to the flow direction of the liquid, and is 15 °. Further, when the diameter R1 of the tubular portion 21a is ₁ , the diameter R6 of the gas mixing hole ₃ is 0.29.
In this way, by forming the hole so that the outlet end 3b of the gas mixing hole 3 faces the discharge pipe portion 23, it is possible to prevent backflow of gas and clogging of pollutants. Further, since the angle θ is set to 15 °, it is possible to manufacture the gas at low cost while having the effect of preventing backflow of gas and clogging.
Since the female screw portion 5 is formed in the gas mixing hole 3, for example, a member having a check valve and a male screw portion is screwed and fixed to prevent a backflow of liquid. It is also possible to prevent it more reliably.

Next, a method of generating microbubbles by the microbubble generation unit 1 formed as described above will be described. First, from the tank for storing the liquid, the liquid pressurized through a known pump (not shown) flows into the inflow pipe portion 21 through the hose 8a. At the same time, gas is supplied from the gas mixing hole 3 to the middle stage 22b of the throat. Since the static pressure in the throat 22 is relatively negative, the gas does not require a gas supply device or the like and is naturally sucked into the middle throat 22b through the gas mixing hole 3.
The liquid flowing into the inflow pipe portion 21 is pressurized and has a high pressure, but the static pressure is the lowest in the throat front stage 22a having the smallest diameter. After that, the static pressure gradually increases in the process of being guided to the discharge pipe portion 23 having a larger diameter through the middle stage 22b of the throat and the rear 22c of the throat. Therefore, the gas sucked into the middle stage 22b of the throat dissolves in the liquid. After that, when the pressure of the pressurized liquid decreases, the gas dissolved in the liquid becomes supersaturated. Then, the gas that cannot be dissolved in the liquid becomes microbubbles, which generates microbubbles.

Next, the purification of contaminated water by the water purification system will be described with reference to FIG. FIG. 2 shows a system configuration diagram of the water purification system of the first embodiment. As shown in FIG. 2, the water purification system 10 floats and separates the microbubble generation unit 1, the contaminated water tank 6 that supplies contaminated water to the microbubble generation unit 1, and the microbubbles discharged from the microbubble generation unit 1. It consists of 7. The contaminated water tank 6 and the microbubble generation unit 1 are connected by a hose 8a, and the microbubble generation unit 1 and the septic tank 7 are connected by a hose 8b. The microbubble generation unit 1 and the hose 8a are connected by using a joint 9a having a female screw portion (not shown), and similarly, the microbubble generation unit 1 and the hose 8b are connected to the female screw portion (not shown). ) Is connected using a joint 9b.

The contaminated water containing the contaminated material in the contaminated water tank 6 is pumped from the contaminated water tank 6 by a pump (not shown) and flows into the microbubble generation unit 1 through the hose 8a. In this process, it is pressurized by a pump and flows into the microbubble generation unit 1 in a high pressure state. For the inflowing liquid, microbubbles are generated by the microbubble generation method of the microbubble generation unit 1 described above.

Since the generated microbubbles are negatively charged, the positively charged pollutants contained in the contaminated water adhere to the generated microbubbles while passing through the discharge pipe portion 23 of the microbubble generation unit 1. Then, the microbubbles to which the contaminated substance is attached are conveyed to the septic tank 7 through the hose 8b together with the liquid from which the contaminated substance has been removed.

The microbubbles that have reached the septic tank 7 float in the septic tank 7 with contaminants attached due to the rising nature of the microbubbles. After that, the microbubbles disappear in the ascending process, and only the pollutants are retained in the upper part of the septic tank 7. Since the microbubbles are gradually rising, the pollutants retained in the upper part of the septic tank 7 continue to accumulate in the upper part of the septic tank 7. After the pollutants are levitated and separated in this way, the scrubber 7a provided on the upper part of the septic tank 7 scrubs and recovers the pollutants that have floated and accumulated. In this way, pollutants are removed and contaminated water is purified.

The water purification system 10 of Example 1 can also be used, for example, to float and separate tritium from contaminated water containing tritium (tritium). Further, the microbubble generation unit 1 of Example 1 can also be used for producing carbon dioxide gas-containing water or carbon dioxide gas-containing liquid fertilizer for hydroponics, or for producing an emulsion fuel. Specifically, water or liquid fertilizer containing carbon dioxide gas can be generated by supplying water or liquid fertilizer from the inflow pipe portion 21 of the microbubble generation unit 1 and supplying carbon dioxide gas from the gas mixing hole 3. When the water or liquid fertilizer is supplied in hydroponic cultivation, carbon dioxide gas evaporates from the water or liquid fertilizer supplied to the roots of the plant, and the carbon dioxide gas comes into direct contact with the stomata on the back side of the leaves of the plant. As a result, carbon dioxide gas can be efficiently absorbed by a plant having a property of absorbing carbon dioxide gas from the stomata on the back side of the leaf. Further, by supplying water and oil from the inflow pipe portion 21 of the microbubble generation unit 1, water can be dispersed in the oil to generate an emulsion fuel. As a result, the emulsion fuel can be easily produced without using the surfactant conventionally used for producing the emulsion fuel.

FIG. 3 shows a cross-sectional image of the microbubble generation unit of the second embodiment. As shown in FIG. 3, the microbubble generation unit 11 has an inflow pipe portion 21 into which the pressurized liquid flows in, a discharge pipe portion 23 to discharge the generated microbubbles, and an inflow pipe, as in the first embodiment. It is composed of a throat portion 22 connecting the portion 21 and the discharge pipe portion 23.
However, unlike the first embodiment, the throat portion 22 is composed of two stages, a throat front stage 22a and a throat rear stage 22c, and the gas mixing hole 3 is formed on the wall surface defining the throat rear stage 22c with microbubbles. The outlet end 3b is formed as a hole with respect to the generation unit 11 so as to face the downstream side of the flow of the liquid.
By forming the throat portion 22 in two stages in this way, it becomes easier to manufacture and it becomes possible to manufacture the throat portion 22 at low cost. Further, since the gas mixing hole 3 is provided on the wall surface defining the throat rear stage 22c having a larger diameter instead of the throat front stage 22a having the smallest diameter, it is possible to effectively dissolve the gas in the liquid. be.

The present invention is useful as a contaminated water purification device. It can also be used as a device for desalination of seawater.

1,11 Micro bubble generation unit 3 Gas mixing hole 3a Inlet end 3b Outlet end 4a, 4b Male screw part 5 Female screw part 6 Contaminated water tank 7 Septic tank 7a Scrubber 8a, 8b Hose 9a, 9b Fitting 10 Water purification system 21 Inflow pipe part 21a, 23a Cylindrical part 21b, 23b Conical base part 22 Throat part 22a Throat front part 22b Throat middle part 22c Throat part rear part 23 Discharge pipe part R diameter θ angle

Claims (5)

The inflow pipe where the pressurized liquid flows in, and
The discharge pipe section that discharges the liquid containing microbubbles,
A throat portion located between the inflow pipe portion and the discharge pipe portion and having a smaller pipe cross section than the inflow pipe portion and the discharge pipe portion.
A hole formed in the wall surface of the throat or the discharge pipe to allow gas to be mixed into the throat, and the angle between the flow direction of the liquid and the mixing direction of the gas intersects at an acute angle. Hole,
Equipped with
The inner diameter of the throat portion is formed in a three-step step shape that expands toward the discharge pipe portion side.
The outlet end of the gas mixing hole is a microbubble generation unit characterized in that the inner diameter of the throat is formed in a step other than the narrowest. The microbubble generation unit according to claim 1 , wherein the outlet end of the gas mixing hole is provided at a position in the middle of the three stages. The microbubble generation unit according to claim 1 or 2 , wherein the angle is in the range of 60 to 80 °. The microbubble generation unit according to any one of claims 1 to 3 , wherein a check valve is provided at the inlet end of the gas mixing hole. The microbubble generation unit according to any one of claims 1 to 4 .
A contaminated water tank that supplies contaminated water to the inflow pipe of the unit,
A septic tank that floats and separates the liquid containing microbubbles discharged from the discharge pipe of the unit.
A water purification system equipped with.

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