JP3081983B2 - Fine bubble generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microbubble generator as a flotation separator in the field of wastewater treatment and a microbubble generator used in various fields such as a microbubble generator and a gas dissolving apparatus in various industrial fields. .

[0002]

2. Description of the Related Art A conventional bubble generating device is a device for generating gas by depressurizing a gas that is potentially dissolved in water, or forcibly dissolving a pressurized gas in water in a special pressure vessel. An apparatus or the like that generates air bubbles by returning the pressure to a normal pressure state after use (hereinafter, referred to as the former) is used.

[0003] As another bubble atomizing and dispersing apparatus, there is an apparatus in which a water pump having a nozzle for gas-liquid mixing at a discharge portion is disposed in a tank (Japanese Utility Model Laid-Open No. 4-57300). Hereinafter the latter).

[0004]

The former air bubble generator is a powerful blower for generating a depressurized / pressurized state.
In addition to the need for a pressure control device such as a compressor and the need for a decompression tank or a pressurized tank in the process, energy consumption during operation of the device is large.
The scale of the device becomes large, and miniaturization is difficult. Power costs associated with energy consumption are high. There is a drawback that noise is generated with the operation of the blower compressor.

[0005] In addition, the latter air bubble dispersing and dispersing apparatus is not capable of sufficiently reducing air bubbles by a simple mixing operation of air bubbles and water, and is capable of substantially obtaining fine air bubbles having a diameter of 1 mm or less. difficult. When used in a solid-liquid separator in the wastewater treatment field, when the water in the tank is circulated and used as bubble generation water, the solid content is destroyed by strong stirring by the rotating blades inside the water supply pump, There is a drawback that the solid matter is dispersed due to the generation of a violent water flow discharged from the water supply pump, and the quality of the treated water deteriorates.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has a simple structure and a small size, and is used in various fields such as a flotation apparatus in a wastewater treatment field, a microbubble generator in various industrial fields, and a gas dissolution apparatus. It is an object of the present invention to provide a microbubble generating device which can obtain microbubbles ideal for application to a device.

[0007]

According to the present invention, there is provided a microbubble generator according to the present invention, wherein each discharge port of a pump having two rotating blades having different discharge pressures, one of which has a high discharge pressure and the other has a low discharge pressure. Is connected by a pressure-resistant pipe, a supply pipe for supplying water together with air is connected to a suction port of a pump having a high discharge pressure among the pumps, and a flow rate for controlling flow rate and pressure is connected to a suction port of a pump having a low discharge pressure. A nozzle provided with an adjustment valve is provided, and fine bubbles are generated from the nozzle by utilizing a pressure difference when both pumps are operated.

A small air pump for quantitatively mixing air and an air supply nozzle having a flow rate adjusting function are connected to a supply pipe connected to the suction port of the high discharge pressure pump. Further, the pump having the two rotating blades is a centrifugal pump, and a pump having a low discharge pressure is installed in a water tank or floated above water.

[0009]

The microbubble generator according to the present invention has a basic principle in which a gas is dissolved in water under pressure as in the pressurized bubble generator described in the former of the prior art section, and then the pressure is reduced to normal pressure. It is common that the gas having the difference in the saturation solubility of the gas under each pressure is precipitated as bubbles. However, while the former conventional pressurized bubble generator uses a powerful compressor, the microbubble generator according to the present invention has a discharge at one high discharge pressure and another at a low discharge pressure. The discharge ports of the pumps having two rotating blades having different pressures are connected by pressure-resistant pipes, and by operating both pumps simultaneously, a pressure difference is generated inside the connected pressure-resistant pipes.

The suction port of a pump having rotating blades of high discharge pressure functions as a suction port of the apparatus, and the suction port of a pump having rotating blades of low discharge pressure functions as a discharge port of the apparatus. Is equipped with a small air pump for quantitative mixing of air and an air supply nozzle with a flow rate control function, and a flow rate control at the discharge port of this device for the purpose of controlling the flow rate and the pressure inside the device. A nozzle equipped with a valve is provided, which enables the gas to be dissolved in water without using a powerful compressor, a pressurized tank, or the like, thereby realizing the above-mentioned problem.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be specifically described below with reference to the drawings. (Structure of the device) A water tank 8 (400 mm wide × 7 long in this example)
(00 mm × 500 mm in depth and an effective volume of 120 liters were used, but the size is not necessarily limited to this). At the end, the discharge water amount is, for example, 5 m ³ / hr, and the discharge water pressure is 5 kgf / cm.
^The discharge port of the multi-stage centrifugal pump 1 having a capacity of ² (refers to a pump having rotary blades with high discharge pressure) (the pump is not limited to the spiral type as long as it has rotary blades) Is a submersible centrifugal pump 4 having a capacity of, for example, 10 m ³ / hr and a discharge water pressure of 1 kgf / cm ² (refers to a pump having a rotary blade with a low discharge pressure). (Not limited to the formula).

The suction port of the pump 1 having the rotary blades with high discharge pressure is connected by a water supply pipe 9 to another water tank 14 filled with water. An air supply pipe 11 is connected to a suction port of the pump 1 having a rotating blade with a high discharge pressure from a small-sized air pump 10 of a dry cell type so that gas can be pumped quantitatively. However, the capacity of the air pump at this time is sufficient to overcome the water pressure due to the difference in water level between the connection between the water supply pipe 9 and the air supply pipe 11 and the water tank 14 connected thereto, and is used in a domestic fish tank. That is, a discharge capacity of 1000 ml / min or less is also possible. A nozzle (not shown) provided with a flow rate control valve 12 for the purpose of flow rate adjustment and pressure adjustment during operation is provided at the suction port 6 of the pump 4 having a rotor blade with a low discharge pressure, that is, the discharge port of the present apparatus. installed.

(Operation of the apparatus) Here, both pumps 1, 4
At the same time, each pump starts suctioning water. However, since the pump 4 is lower than the discharge pressure of the pump 1, the water sent from the pump 1 flows inside the pump 4 in a direction opposite to the original flow direction of the pump. The liquid is discharged from the suction port 4, that is, the discharge port 6 of the present apparatus at, for example, 1 m ³ / hr. At this time, a pressure of, for example, 1 kgf / cm ² , which is equal to the discharge pressure capability of the pump 4, should be generated inside the pressure-resistant pipe 7 connecting the respective pumps 1, 4. When water passes through a nozzle (not shown) provided with a flow rate control valve 12 provided at the discharge port, a passage resistance is generated, and the pressure in the pipe reaches, for example, 4 kgf / cm ² .

(Generation of Air Bubbles) A dry battery type small air pump 10 passes through a water supply pipe 9 connected to a suction port of the pump 1 through an air supply pipe 11, for example, 200 to 500 c.
A gas of about c / min is quantitatively pumped. The gas is mixed with water to form bubbles having a diameter of several mm and supplied to the inside of the pump 1. Bubbles are destroyed by the rotating blades inside the pump 1 and become, for example, about 1 to 2 mm in diameter. Connected pressure-resistant pipe 7
Is pressurized at, for example, 4 kgf / cm ² , so that the gas dissolves in water to a saturated dissolution concentration. The water in which the gas is dissolved at a pressure of, for example, 4 kgf / cm ² passes through the inside of the pump 4, is dispersed again by the rotating blades of the pump 4, and finally passes through a nozzle (not shown) equipped with a flow control valve 12. Then, when discharged into the water tank, it is released from the pressurized state to the normal pressure environment. When the water in which the gas thus dispersed is dissolved is discharged from the nozzle, the ambient pressure is reduced to a normal pressure state. (100μ
m) Precipitates as the following fine bubbles.

When this apparatus is operated for 40 seconds, for example, the water in the water tank 8 becomes turbid because light passing through the water is scattered by fine bubbles. The smaller and larger the amount of generated bubbles, the greater the degree of light scattering, and thus the shorter the reach of light. For example, the amount of water discharged by the present apparatus for 40 seconds is about 11 liters, and the amount of water to be mixed corresponds to an effective volume of the water tank 8 of, for example, 10% of 120 liters. The present apparatus, a conventional bubble generator using a compressor and a pressurized tank, and a conventional air-bubble bubble generator using a gas-liquid mixing nozzle and a water pump are operated under the same conditions, and operated. Table 1 shows the results of comparing the light reaching distances of the light (wavelength 780 nm).

[0016]

[Table 1]

As shown in Table 1, it has been confirmed that the form and amount of bubbles generated in the present apparatus are equivalent to those of the bubble generating apparatus used in the pressure flotation method.

In a state where the pulp is dispersed in the water tank 8, the present apparatus and the above-described conventional two types of bubble generating apparatuses are provided.
The ability to generate air bubbles and cause the air bubbles to adhere to the pulp fiber and float on the water surface was compared. 100 mg /
l of pulp powder was introduced, air bubbles were introduced from each device for 40 seconds, and then the pulp fiber component remaining in water after removing the pulp fiber component which floated by standing still for 5 minutes is shown in Table 2. Show.

[0019]

[Table 2]

As shown in the above Table 2, it was confirmed that the present apparatus also had the same effect as the bubble generating apparatus used in the pressure flotation method in terms of the separation effect by the fine bubbles.

[0021]

According to the microbubble generator according to the present invention, each discharge port of a pump having two rotating blades having different discharge pressures, one of which has a high discharge pressure and the other has a low discharge pressure, is connected to a pressure-resistant pipe. A supply pipe for supplying water together with air to a suction port of a pump having a high discharge pressure among the pumps, and a flow control valve for performing flow rate and pressure control is provided at a suction port of the pump having a low discharge pressure. A nozzle was installed, and fine bubbles were generated from the nozzle using the pressure difference during the operation of both pumps, so that gas can be dissolved in water with a simple structure using a commercially available pump. In a water tank at normal pressure than a pump having a rotor with low discharge pressure,
The gas that has become supersaturated due to the pressure difference has a diameter of 0.1
It can be generated as very small microbubbles of less than mm, and exhibits excellent effects in various fields.

Further, the structure of the microbubble generator according to the present invention is a simple structure based on a pump having two rotating blades facing each other. The need for a compressor is eliminated, and the operating cost can be kept low. In particular,
If applied to the flotation separation method in wastewater treatment, the state of generated bubbles can generate bubbles comparable to the conventional pressure flotation method.In addition, because the device structure is simple and small, it can be applied to small and medium-sized devices. The introduction is also feasible.

Further, when used as a gas dissolving apparatus in the field of fish farming, the discharged water can be used as a water supplying apparatus rich in dissolved gas since the gas is in a saturated concentration state. Further, since it is small and inexpensive, it can be widely used as a small-scale auxiliary device having a limited installation space.

Furthermore, by connecting a small air pump and an air supply nozzle to a supply pipe connected to the suction port of the high discharge pressure pump, quantitative mixing of air is reliably performed, and flow rate is adjusted. It can be performed properly and can be operated continuously.

The pump having the two rotors is a centrifugal pump. By installing a pump having a low discharge pressure in a water tank or floating above the water, a commercially available pump can be used. Pressure pump installation space
There is no need to secure the outside of the water tank, and a more compact design can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing one embodiment of the present invention.

[Explanation of symbols]

1 high discharge pressure spiral pump 2 high discharge pressure spiral pump suction port (suction port of this device) 3 high discharge pressure spiral pump discharge port 4 low discharge pressure spiral pump 5 spiral pump discharge port 6 spiral pump suction port (Discharge port of this device) 7 Pressure-resistant pipe 8 Water tank 9 Water supply pipe 10 Small air pump 11 Air supply pipe 12 Flow control valve 13 Flange 14 Another water tank

Claims (3)

(57) [Claims] 1. A pump having two discharge blades having different discharge pressures, one of which has a high discharge pressure and the other of which has a low discharge pressure, has respective discharge ports connected by pressure-resistant piping. A supply pipe that supplies water together with air is connected to the suction port of the pressure pump, and a nozzle equipped with a flow rate adjustment valve that controls the flow rate and pressure is installed at the suction port of the low discharge pressure pump. A microbubble generator, wherein microbubbles are generated from the nozzle using a pressure difference at the time. 2. A small air pump for quantitatively mixing air into a supply pipe connected to a suction port of the high discharge pressure pump.
2. The microbubble generator according to claim 1, wherein a pump and an air supply nozzle having a flow control function are connected. 3. The microbubble generation according to claim 1, wherein the pump having two rotating blades is a centrifugal pump, and a pump having a low discharge pressure is installed in a water tank or installed floating on water. apparatus.