JP2006136819A - Liquid processing apparatus and liquid processing system using the same - Google Patents

Abstract

【Task】
Providing liquid processing technology that maintains the quality of liquid resources and enables sterilization and reuse.
[Solution]
A supersonic flow is formed by a liquid into which a gas is injected, and bubbles in the liquid are destroyed by the supersonic flow to generate microbubbles. The microbubbles are irradiated with ultrasonic waves to individually form the microbubbles. Cavitation is crushed, and bacteria in the liquid are killed at high temperature and high pressure at the time of cavitation crushing.
[Selection] Figure 2

Description

  The present invention relates to a technique for sterilizing Legionella bacteria in a liquid such as hot spring water, and more particularly to a sterilization technique in a processing system that circulates and reuses a liquid such as a circulating hot spring system.

  Conventionally, liquid sterilization techniques include those using a sterilizing agent such as chlorine and those using ultrasonic waves. In the case of using ultrasonic waves, the target liquid is irradiated with ultrasonic waves and sterilized and sterilized by shock wave pressure by cavitation. In addition, as a document description technique related to the present invention, for example, the technique described in Japanese Patent Application Laid-Open No. 2003-230824 (hereinafter referred to as Patent Document 1), Ultrasonic Technical Handbook, Junichi Miyoshi, Nikkan Kogyo Shimbun There are techniques described in (hereinafter referred to as Non-Patent Document 1), cavitation basics and recent advances, edited by Yoji Kato, and Tsuji Shoten (hereinafter referred to as Non-Patent Document 2). Patent Document 1 describes a technique in which a surfactant is included in a liquid in order to suppress the coalescence of a large number of micro bubbles generated in a micro-bubble generating unit. The relationship between the action of bubbles generated in the liquid and the ultrasonic waves is described, and Non-Patent Document 2 describes the density and action of bubbles generated in the liquid.

Japanese Patent Laid-Open No. 2003-230824 Ultrasonic Technical Handbook, Junichi Miyoshi, Nikkan Kogyo Shimbun Cavitation basics and recent progress, Yoji Kato, Tsuji Shoten

Although the liquid quality can be maintained with the above-mentioned conventional technology in which sterilization is performed by irradiating a liquid with ultrasonic waves, the sterilization rate is low because the number of cavitation nuclei in the liquid is small compared to the number of bacteria, and about 3% is the limit. It is.
An object of the present invention is to make it possible to further improve the sterilization rate without using a sterilizing agent in a liquid processing technique for performing a sterilization process in a liquid in view of the situation of the above prior art.
An object of the present invention is to provide a liquid processing technique that solves the above-described problems and enables liquid resources to be sterilized and reused with high efficiency without changing the quality.

  In order to solve the above-described problems, in the present invention, as a liquid processing apparatus for sterilizing a liquid, a supersonic flow is formed with a liquid into which gas is injected on a liquid flow path, and the supersonic flow causes the liquid to flow into the liquid. The microbubbles are generated by destroying the bubbles, and the microbubbles are irradiated with ultrasonic waves to cavitate the microbubbles independently (breaking the bubbles based on the volume change of expansion and contraction). The liquid is sterilized with the energy generated when the cavitation is crushed.

  According to the present invention, bacteria in a liquid can be effectively eliminated without changing the quality of the liquid resource. The operation cost can be reduced by reusing the liquid.

The best mode for carrying out the present invention will be described below with reference to the drawings.
1-4 is explanatory drawing of the Example of this invention. FIG. 1 is a diagram showing a configuration example of a circulating hot spring water treatment system as an embodiment of the liquid treatment system of the present invention, FIG. 2 is a configuration example diagram of a liquid treatment apparatus as one embodiment of the present invention, and FIG. FIG. 4 is a structural example diagram of a microbubble generating unit constituting the liquid processing apparatus of FIG. 2, and FIG. 4 is a characteristic diagram showing the relationship between the bubble content in the liquid and the sound velocity.

  In FIG. 1, 1 is a bathtub, 2 is hot spring water, 3 is a hair collector for capturing hair in the hot spring water 2, 4 is a pump for forcibly circulating the hot spring water 2, 5 is a hot spring Filter for increasing cleanliness of hot spring water by decomposing and removing organic waste in the water by microbial activity, 6 is a liquid processing apparatus of the present invention for sterilizing a filtered liquid such as hot spring water 2, Is a heater for raising the temperature of hot spring water.

  In the configuration of FIG. 1, for example, hot spring water 2 used for bathing in the bathtub 1 is discharged from the drain of the bathtub 1, hair is removed by the hair collector 3, and the water pressure is increased through the pump 4. And sent to the filter 5 side. After the organic waste is decomposed and removed by the filter 5, it is further supplied to the liquid processing device 6. In the liquid processing apparatus 6, when bacteria such as Legionella bacteria in the hot spring water 2 are present, the bacteria are exterminated by a high temperature and high pressure generated by cavitation collapse of microbubbles. The temperature of the sterilized hot spring water 2 is raised to a predetermined temperature by the heater 7 and is appropriately supplied to the bathtub 1. Thus, in the circulation type hot spring water treatment system of FIG. 1, the hot spring water 2 is a circulation system formed by the bathtub 1, the hair collector 3, the pump 4, the filter 5, the liquid treatment device 6, and the heater 7. Is circulated and reused while being sterilized.

FIG. 2 is a configuration diagram of a liquid processing apparatus 6 as an embodiment of the present invention.
In FIG. 2, 10 is a component of the liquid processing apparatus 6 that performs sterilization processing of liquid such as hot spring water, a micro bubble generating unit that generates micro bubbles in liquid such as hot spring water, and 11 is a liquid. An ultrasonic irradiating unit 13 that is a component of the processing device 6 and irradiates ultrasonic waves to cavitate the generated microbubbles, so that the microbubble generating unit 10 can generate microbubbles. This is a gas injection unit that forcibly injects gas into the microbubble generation unit 10. The gas injection unit 13 may not be included in the liquid processing apparatus 6 and may be provided as a separate component from the liquid processing apparatus 6. In the micro-bubble generating unit 10, after a gas such as air is injected into a liquid such as hot spring water so that bubbles are generated in the liquid, the liquid is put into a supersonic flow state, for example, a diameter of 1 × 10 ^-6 m microbubbles are generated. The ultrasonic irradiation unit 11 irradiates the generated microbubbles with ultrasonic waves, so that the microbubbles are individually cavitation crushed before the bubble nuclei merge with each other. That is, each of the microbubbles undergoes a large volume change of expansion and contraction due to the ultrasonic wave, and is destroyed in the process of the volume change. At the time of the cavitation crushing, each microbubble to be broken generates a high temperature and a high pressure. Bacteria such as Legionella bacteria present in liquids such as hot spring water are killed by one or both of high temperature and high pressure during the cavitation collapse.

FIG. 3 is a diagram illustrating a configuration example of the microbubble generation unit 10 included in the liquid processing apparatus 6 of FIG.
3, (a) is a sectional view of the microbubble generator 10, (b) is a diagram showing an example of distribution characteristics of the flow velocity v in the liquid in the flow direction of the microbubble generator 10 of (a), (C) is a diagram showing an example of the distribution characteristic of the pressure p in the same liquid, (d) is a diagram showing an example of the characteristic of the bubble content rate (hereinafter referred to as bubble content rate) V in the liquid, (e) ) Is a diagram showing an example of the distribution characteristics of the sound velocity c in the same liquid, and (f) is a diagram collectively showing the distribution characteristics of the flow velocity v in (b) and the distribution characteristics of the sound velocity c in (e). is there.

  In FIG. 3 (a), 23 is a liquid inlet through which liquid is introduced, 14 is a gas inlet through which gas is injected into the liquid, and 21 is a first part through which gas is injected into the liquid. The main body part 28 is a throttle part as a second part that increases the flow rate of the liquid more than the speed of sound in the liquid and increases the content rate of bubbles by greatly reducing the cross-sectional area of the flow path with respect to the main body part 21. Is a divergent nozzle part as a third part that is formed continuously with the throttle part 28 and breaks down the bubbles in the liquid and generates microbubbles by the entry of the supersonic flow generated in the throttle part 28; Is the tip of the divergent nozzle portion 22 in the axial direction. The main body portion 21 forms a cylindrical channel, and bubbles are generated in the liquid by a gas such as air injected from the gas inlet 14 in the cylindrical channel. The throttle portion 28 has a flow path cross-sectional area of 1/10 or less with respect to the main body portion 21. The liquid containing bubbles is forced to flow from the cylindrical channel of the main body 21 into the reduced channel of the throttle unit 28. The distal end portion 29 of the divergent nozzle portion 22 discharges the processed liquid. When the opening angle of the tip portion 29 is less than 40 °, the flow velocity distribution characteristic and pressure distribution characteristic of the liquid flowing through the divergent nozzle part 22 can be stabilized.

  3A to 3F, when a liquid is introduced into the main body portion 21, a gas is injected into the liquid from the gas injection port 14, and bubbles are formed in the liquid. The liquid containing the bubbles is forced to flow from the main body portion 21 to the throttle portion 28, and the flow velocity v of the liquid begins to increase in the throttle portion 28 as apparent from Bernoulli's theorem (FIG. 3B). The pressure p begins to decrease (FIG. 3 (c)). When the pressure p decreases, the bubbles contained in the liquid expand and the bubble content V increases (FIG. 3 (d)). Further, the sound velocity c in the liquid decreases as the bubble content V increases. (FIG. 3 (e)). This tendency is remarkable at the positions of the regions A and B (FIG. 3A) in the divergent nozzle portion 22 past the position of the throttle portion. The speed of sound c in the liquid becomes the lowest value when the bubble content V in the liquid increases to about 50%, for example, and is about 23.9 m / s (FIG. 4). From the time when the liquid flows into the region A, the flow velocity v of the liquid exceeds the sound velocity c in the liquid and becomes a supersonic flow. The supersonic flow is accelerated by the flow path diameter expanding structure of the divergent nozzle portion 22. The decrease in the pressure p in the supersonic flow reaches, for example, several atmospheres. If the flow velocity of the main body 21 is 1 m / s, for example, and the rate of reduction of the flow path cross-sectional area in the throttle 28 is 1/30, the flow rate in the region A is 30 m / s.

The position in the axial direction of the distal end portion 29 of the divergent nozzle portion 22, the liquid is in a substantially stationary state, the pressure is a constant value p _b of about atmospheric pressure. Any region C of divergent nozzle portion 22 near the tip portion 29, the liquid is in a substantially stationary state, the pressure of the liquid is in a static pressure state close to the constant value p _b. For this reason, in the position x1 (FIG. 3A) in the region B adjacent to the region C, a collision between the supersonic flow liquid from the region A side and the substantially stationary liquid occurs, A shock wave is generated. Up to or near position x1, the liquid increases in flow velocity v (FIG. 3 (b)), decreases in pressure p (FIG. 3 (c)), increases in bubble content V (FIG. 3 (d)) and The sonic velocity c continues to decrease (FIG. 3 (e)), and the supersonic flow state is maintained. However, after the collision, the liquid pressure suddenly recovers at or near the position x1, and thereby the region B , The bubbles in the liquid in C are greatly reduced, and the bubble content V decreases. For this reason, the speed of sound c in the liquid rises to about 1400 m / s. At the position x1 or in the vicinity thereof, as described above, the supersonic flow liquid enters the substantially stationary liquid, so that the expanded bubbles are destroyed and more microbubbles are generated. That is, in the region B, bubbles in the liquid are destroyed by the supersonic flow, and microbubbles are generated.

The ultrasonic irradiation unit 11 (FIG. 2) irradiates the microbubbles generated in the region B with ultrasonic waves, and crushes the microbubbles independently. That is, when an ultrasonic wave is irradiated, microbubbles serving as nuclei expand during the negative pressure period of the ultrasonic wave to generate cavitation bubbles. The expanded cavitation bubbles collapse in the process of contracting during the positive pressure period of ultrasonic waves. At the time of crushing, a strong shock wave that diffuses spherically around the crushing point, high temperature, and high pressure are generated. Bacteria such as Legionella in the liquid are killed by energy based on temperature and pressure generated during the cavitation collapse. When the frequency of the ultrasonic wave irradiated to the microbubbles from the ultrasonic irradiation unit 11 is 15 kHz, for example, cavitation collapse of 15000 times / s occurs. Depending on the cavitation collapse, for example, 10000 / m ⁻³ microbubbles are generated, and the number of bacteria in the liquid can be increased. Further, the temperature generated when the cavitation is collapsed reaches several thousand degrees Celsius, and the pressure reaches several tens of thousands Pa. Bacteria are killed corresponding to each of the microbubbles by the energy of one or both of the temperature and pressure.

  5 to 8 are other embodiments of the liquid processing apparatus. 1 to 4 used in the description of FIGS. 5 to 8 are used with the same reference numerals as those in FIGS.

  FIG. 5 shows a configuration in which the microbubble generation unit 10 and the ultrasonic wave irradiation unit 11 constituting the liquid processing apparatus 6 are arranged as the liquid processing apparatus 6, that is, in the divergent nozzle unit 22 of the microbubble generation unit 10. It is a structural example at the time of arranging the ultrasonic irradiation part 11 in the insertion state. The basic configuration and action of the microbubble generator 10 are the same as in the configuration of FIG. In FIG. 5, reference numeral 30 denotes an ultrasonic transducer that constitutes the ultrasonic irradiation unit 11. The microbubbles generated by the supersonic flow in the region B are irradiated with ultrasonic waves from the ultrasonic transducer 30 to cavitate the microbubbles individually. Bacteria in the liquid are killed by the cavitation collapse.

  FIG. 6 is also a configuration in which the microbubble generating unit 10 and the ultrasonic irradiation unit 11 constituting the liquid processing apparatus 6 are arranged to overlap each other. In the configuration of FIG. 6, an example is provided in which a facing surface facing the ultrasonic transducer as the ultrasonic irradiation unit 11 is provided across the portion of the region B of the divergent nozzle unit 22 of the microbubble generation unit 10. is there. The basic configuration and action of the microbubble generator 10 are the same as in the configuration of FIG. In FIG. 6, 31 is an ultrasonic transducer constituting the ultrasonic irradiation unit 11, and 33 is a facing surface. The distance D between the ultrasonic transducer 31 and the facing surface 33 is set to be approximately an integral multiple of a quarter wavelength of the ultrasonic wave. With such a configuration, the microbubbles generated by the supersonic flow in the region B are cavitation crushed with high efficiency by the ultrasonic waves from the ultrasonic transducer 31.

  FIG. 7 is also a configuration in which the microbubble generation unit 10 and the ultrasonic irradiation unit 11 constituting the liquid processing apparatus 6 are arranged to overlap each other. The configuration in FIG. 7 is an example in the case where the periphery of the region B of the divergent nozzle portion 22 of the microbubble generator 10 is surrounded by an ultrasonic transducer as the ultrasonic irradiation unit 11. The basic configuration and action of the microbubble generator 10 are the same as in the configuration of FIG. In FIG. 7, reference numeral 32 denotes a cylindrical ultrasonic transducer that constitutes the ultrasonic irradiation unit 11. The ultrasonic transducer 32 irradiates the region B with ultrasonic waves from its periphery, and crushes the microbubbles in a highly efficient state.

  FIG. 8 shows a case where a swirl of liquid is formed in advance in the main body 21 of the microbubble generator 10 to generate vortex cavitation. In FIG. 8, 34 is a swirl flow generating mechanism provided in the main body 21, and 35 is a vortex cavitation generated by the swirl flow generating mechanism 34. The swirl flow generating mechanism 34 converts the laminar flow from the liquid inlet 23 into a swirling swirl flow. Due to the generation of the vortex, vortex cavitation 35 due to dissolved gas is generated on the axis of the vortex, and the vortex cavitation 35 is expanded into a larger bubble by the throttle portion 28. For this reason, in the region B, more and more microbubbles are formed, and the formed microbubbles are cavitation crushed with high efficiency. In this configuration, even when the gas content is low, bubbles (vortex cavitation 35) are formed on the axis of the vortex. In addition, by forcibly introducing gas from the outside (gas injection unit 13), the gas-liquid ratio can be arbitrarily set or adjusted, or the gas ratio in the liquid can be increased. The flow rate ratio between liquid and gas is expected to be possible up to about 20%, for example. It is also possible to control the size of the generated microbubbles by controlling the flow rate ratio.

  According to the embodiment of the present invention described with reference to FIGS. 1 to 8 above, bacteria in the liquid can be efficiently removed without changing the quality of the liquid such as hot spring water, and the circulation type liquid treatment Is possible. The operation cost can be reduced by reusing the liquid.

  In addition, although the Example of the said FIGS. 1-8 demonstrated about the liquid processing apparatus used for a circulation type hot spring water processing system, this invention is not limited to this. The system may not be a circulation type, the liquid treatment device may be used in addition to the hot spring water treatment system, and the liquid to be sterilized may be, for example, seawater, river water, lake water, dam water, sewage, Liquids other than hot spring water, such as sewage tank water, aquaculture tank water, aquarium water for aquatic organisms, bioreactor liquid, hydroponics water, and the like may be used. Further, the liquid processing apparatus is not limited to the one shown in FIGS. For example, the main body portion 21 and the divergent nozzle portion 22 may have a separate configuration or an integrated configuration.

It is a figure which shows the structural example of the circulation type hot spring water treatment system as an Example of this invention. It is a block diagram of a liquid processing apparatus as an embodiment of the present invention. FIG. 3 is a configuration example diagram of a microbubble generator that constitutes the liquid processing apparatus of FIG. 2. It is a characteristic view which shows the relationship between the bubble content rate in a liquid, and a sound speed. It is another Example figure of a liquid processing apparatus. It is another Example figure of a liquid processing apparatus. It is another Example figure of a liquid processing apparatus. It is another Example figure of a liquid processing apparatus.

Explanation of symbols

1 ... tub,
2 ... hot spring water,
3 ... hair collector,
4 ... pump,
5 ... filter,
6 ... Liquid treatment device,
7 ... heater,
10: Microbubble generator,
11 ... ultrasonic irradiation part,
13 ... gas injection part,
23. Liquid inlet,
14 ... Gas inlet,
21 ... body part,
28: Aperture part,
22 ... Suehiro nozzle part,
29 ... the tip,
30, 31, 32 ... ultrasonic transducer,
33 ... opposite surface,
34 ... Swirl flow generating mechanism,
35 ... Vortex cavitation.

Claims (6)

A liquid processing apparatus for sterilizing a liquid,
On the liquid flow path, the flow of the liquid into which the gas is injected is a supersonic flow, and the microbubble generation unit generates a microbubble by destroying the bubbles in the liquid by the supersonic flow;
Ultrasonic irradiation unit for irradiating the microbubbles of the microbubble generating unit with ultrasonic waves, and cavitation crushing the microbubbles individually,
A liquid processing apparatus characterized in that the liquid is sterilized with energy by cavitation collapse of the microbubbles. A liquid processing apparatus for sterilizing a liquid,
The first portion into which the gas is injected on the liquid flow path and the change in the cross-sectional area of the flow path increase the liquid flow rate from the sonic velocity in the liquid to form a supersonic flow and increase the bubble content. A microbubble generating part comprising: a second part to be generated; and a third part that breaks the bubble by the entry of the supersonic flow and generates a microbubble;
Ultrasonic irradiation unit that irradiates the generated microbubbles with ultrasonic waves and cavitates the microbubbles individually, and
And a liquid processing apparatus characterized in that the sterilization processing in the liquid is performed with the energy generated by cavitation collapse of the microbubbles.   In the microbubble generating unit, the second part includes a throttle part in which a cross-sectional area of the flow path is reduced more than that of the first part, and a cross-sectional area of the flow path along the liquid flow direction. The liquid processing apparatus according to claim 2, wherein the liquid processing apparatus has a divergent portion that is gradually increased.   3. The liquid processing apparatus according to claim 1, wherein the microbubble generating unit has a configuration in which an opening angle of a downstream end portion of the flow path is less than about 40 °.   The liquid processing apparatus according to claim 2, wherein the microbubble generation unit is configured such that the first portion generates a swirling flow of liquid. A liquid processing apparatus according to any one of claims 1 to 5, a tank for storing liquid, and a pump for supplying liquid from the tank to the liquid processing apparatus, wherein the liquid is supplied to the tank and the liquid processing apparatus. A liquid processing system characterized in that it is sterilized while circulating between them.

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