JPH07270097A - Method and apparatus for generating cavitation - Google Patents

Abstract

PURPOSE:To effectively generate a cavitation by a simple, low-cost apparatus structure. CONSTITUTION:The apparatus for generating a cavitation comprises a mixer 1 for mixing liquid A with gas B to mixed liquid C, and a cavitation generator 8 for generating the cavitation by feeding the liquid C. The generator 8 has a cylinder 8a in which the liquid C flows, a nozzle 8d provided at a center of the cylinder 8a toward a downstream side to inject high-pressure liquid A or the liquid C, and a slewing guide 8e provided between the cylinder 8a and the nozzle 8d to slew the liquid C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for generating cavitation. More specifically, a method of generating cavitation for performing cleaning or the like by utilizing the cavitation effect that is a shock wave that breaks air bubbles,
A cavitation generator suitable for carrying out this method.

[0002]

2. Description of the Related Art Conventionally, as a method of generating cavitation, for example, the method described in Japanese Utility Model Publication No. 5-39355 is known.

This conventional method for generating cavitation is built in a cleaning device, and a gaseous cavitation is obtained by mixing a cleaning liquid (liquid) forming a pulsating flow and a gas pressure-fed from a gas cylinder with a mixer. Is generated. The cleaning device utilizing the cavitation effect has a feature that it is more effective for cleaning the object to be cleaned having a closed structure than each cleaning means such as disassembly cleaning, chemical cleaning, and jet water cleaning.

[0004]

In the above-mentioned conventional method for generating cavitation, the high pressure regulating valve, the high pressure on-off valve, the accumulator and the like must be equipped as means for forming a high pressure pulsating flow in the liquid. However, there is a problem that the device structure becomes complicated and the manufacturing cost increases.

Further, since the liquid and the gas are mixed and the cavitation is performed at the same time, the liquid and the gas are not sufficiently mixed, and the bubbles formed are not uniform, so that the effective cavitation is performed. There is a problem that it does not occur.

Further, the gas supplied from the gas cylinder must be mixed with the liquid by gas-liquid mixing, and carbon dioxide gas is used as the gas. Therefore, it is necessary to equip each part such as a gas cylinder and pay sufficient attention to gas management under high pressure, which causes a restriction on work.

The present invention has been made in consideration of the above problems, and is suitable for implementing a method for generating cavitation that can effectively generate cavitation with a simple and inexpensive apparatus configuration, and to carry out this method. It is an object of the present invention to provide a cavitation generation device that is effective.

[0008]

In order to solve the above-mentioned problems, the method of generating cavitation according to the present invention is, as described in claim 1, swirling a mixed liquid obtained by mixing a gas with a liquid, and mixing the mixed liquid. A means for injecting the mixed liquid from the swirl center of the liquid toward the downstream side to rapidly reduce the pressure is adopted. Further, as described in claim 2, means for bringing the gas of the mixed liquid into a saturated state or a supersaturated state is adopted.

Further, in order to solve the above-mentioned problems, the cavitation generator according to the present invention has, as described in claim 3, a mixer for mixing a gas with a liquid to form a mixed liquid, and a mixed liquid. It consists of a cavitation generator that is fed in to generate cavitation, and the cavitation generator is composed of a tubular body through which the mixed liquid flows, a conical portion having a tapered outer shape toward the downstream side at the center of the tubular body, and a tubular body. And a conical portion, which is provided between the conical portion and the conical portion, and comprises a swirl guide portion for swirling the mixed liquid. Further, in the cavitation generator of claim 3, as described in claim 4, means for opening a nozzle for injecting a jet flow at the tapered tip can be adopted in the conical portion, or in claim 5. Thus, it is possible to employ means characterized in that the mixer is a vortex pump.

[0010]

According to the above-mentioned means, in the first aspect, the decompressed portion is formed in the flow of the mixed liquid due to the swirling of the mixed liquid, and the formation of the depressurized portion is promoted in the mixed liquid when passing through the tapered outer shape of the conical portion. As a result, cavitation occurs. Cavitation is effectively generated due to the fact that the mixed liquid contains a sufficient amount of gas and the generated bubbles have a uniform size.

According to the second aspect of the invention, in the above-described operation, when the gas is saturated with the liquid, the size of the bubbles generated becomes more uniform, and the cavitation becomes more effective.

In the third aspect, when the cavitation is generated by the device configuration including the cylindrical body, the conical portion, and the swirl guide portion, the passage of the mixed liquid promotes the formation of the reduced pressure to generate the cavitation and the mixed liquid. The turning of is accurate.

In particular, according to the present invention, in addition to the occurrence of the cavitation, a jet flow is ejected from the nozzle, so that the difference between the pressure and the flow velocity of the liquid mixture that causes the cavitation is caused, and the pressure is rapidly reduced so that the super-pressure is reduced. Cavitation occurs.

Further, in the present invention, in the vortex flow pump, the mixed gas is mixed in the liquid as fine bubbles.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a cavitation generating method and a cavitation generating device according to the present invention will be described below with reference to the drawings.

In this embodiment, as shown in FIG. 3, the cleaning device is incorporated in the cleaning liquid supply system of the cleaning device.

The mixer 1 for mixing the liquid B (cleaning liquid) A with the gas B to form a mixed liquid (mixed cleaning liquid) C is preferably composed of a vortex pump. The vortex pump can mix the gas B with the liquid A by stirring to mix the fine bubbles in the mixed liquid C. The mixer 1 is connected to a storage tank 2 in which the liquid A is stored, and as the liquid A, water or a cleaning liquid can be suitably adopted.

The suction side of the mixer 1 is opened to the atmosphere through the valve 3 so that the gas (air) B is sucked in at a negative pressure. Furthermore, this mixer 1
Is controlled by the inverter 4 and is set by a sequencer or the like so that the mixed liquid C can be discharged at a constant pressure.

A pressure dissolution tank 5 is connected to the downstream side of the mixer 1.

The pressure dissolution tank 5 is for holding the pressure of the mixed liquid C and temporarily storing it. In this pressure dissolution tank 5,
An opening / closing valve 6 is provided to discharge the excess gas B to saturate the mixed liquid C. Here, the saturated state means a state in which the dissolution of the gas B is limited under the set pressure and temperature.

Manual valves 7 and 7 ′ are connected to the downstream side of the pressure dissolution tank 5.

The manual valves 7 and 7 ′ maintain the pressure of the mixed solution C in the pressure dissolution tank 5 and regulate the flow rate of the mixed solution C flowing out from the pressure dissolution tank 5. In addition, this manual valve 7
Is connected to the bypass system 12.

A cavitation generator 8 is connected to the downstream side of the manual valve 7 '.

The cavitation generator 8 is shown in FIGS.
As shown in detail in FIG.
b, a conical portion 8c, a nozzle 8d, a swivel guide portion 8e, and a guide vane 8f. The cylindrical body 8a is formed in a cylindrical shape and is connected to the downstream side of the manual valve 7 '. The body portion 8b has a thick cylindrical shape and is installed at the center of the cylindrical body 8a, and has a guide surface 8g that is curved toward the upstream side. The body portion 8b is supported by the swivel guide portion 8e, and although it varies depending on the pressure and the flow velocity, it can be preferably installed at a ratio of 10: 7 with respect to the inner diameter of the cylindrical body 8a. The conical portion 8c has a tapered shape from the body portion 8b toward the downstream side. The nozzle 8d is arranged inside the conical portion 8c, and the discharge port is directed to the downstream side at the center of the cylindrical body 8a. In addition, this nozzle 8d is
It is arranged even outside of a and is connected to the storage tank 2 via a high-pressure pump 9. The turning guide portion 8e is a cylindrical body 8a.
It is hung and fixed between the inner wall and the body portion 8b, and is arranged in a swirl wing shape.

The high-pressure pump 9 supplies a water flow having a constant pressure and flow velocity to the cavitation generator 8, and the nozzle 8d
Is jetted as a jet stream.

In this cavitation generator 8, the mixed liquid C is guided from the upstream side inside the cylindrical body 8a to the guide surface 8g on the barrel portion 8a.
At the same time as being guided around b, it is swung by the swivel guide portion 8e, and the reduced pressure or stirring state is promoted. Since the mixed liquid C passes through the conical portion 8c while swirling, a reduced pressure portion is formed in the flow. That is, the swirling flow D of the mixed liquid C causes an imbalance in pressure to form a low pressure portion. Therefore, cavitation occurs. At this time, the gas B is saturated in the mixed liquid C and the fine bubbles are also mixed, so that the sizes of the formed bubbles are made uniform and the cavitation is effectively generated.

Further, in the cavitation generator 8, the high pressure liquid A is jetted from the nozzle 8d. The injection of the liquid A is performed at the center of the swirling flow D of the mixed liquid C described above, and the pressure of the mixed liquid C and the pressure higher than the flow velocity,
It becomes the flow velocity. Therefore, the mixed liquid C is rapidly decompressed by the jet stream E and cavitation is generated in the mixed liquid F.
Becomes In this case, the jet flow E is always held at a constant difference.

On the downstream side of the cavitation generator 8,
A body 11 to be cleaned is connected via a four-way valve 10.

The four-way valve 10 switches the mixed liquid F in which cavitation has occurred to the normal or reverse direction and sends it into the object to be cleaned 11. The object to be cleaned 11 is, for example, a synthetic resin molding die,
It is a heat exchanger.

The mixed liquid F sent to the object to be cleaned 11 is
The inside of the object to be cleaned 11 is cleaned by a shock wave generated by breaking bubbles generated by cavitation. At this time, due to the cavitation generation structure composed of the swirling flow in the cavitation generator 8 described above, the cavitation becomes super cavitation by the principle of the ejector and generates a micro jet. In this microjet, the shock wave becomes strong because the bubble is not compressed and reduced in size but compressed and deformed.

The mixed liquid F that has passed through the object to be cleaned 11 is
The cleaning residue is removed from the bypass system 12 by the filter 13 and is returned to the storage tank 2.

The storage tank 2 is provided with a level sensor 14 for the liquid level A '. This level sensor 14
Cooperates with the water supply valve 15 to keep the liquid level A ′ of the storage tank 2 constant. A drain valve 16 is provided at the bottom of the storage tank 2.

As described above, in addition to the illustrated embodiment, an embodiment in which the high-pressure mixed liquid C is injected from the nozzle 8c of the cavitation generator 8 can be adopted.

It is also possible to adopt an embodiment in which the liquid mixture C is made into a gas supersaturated state and jetted as a jet flow E, and the gas in a supersaturated state is dispersed and mixed to generate a large amount of cavitation.

[0035]

As described above, the cavitation generating method and the cavitation generating apparatus according to the present invention have a simple structure because the cavitation is generated not by the pulsating flow but by the swirling flow. There is an effect that can cause cavitation. Further, due to this effect, the manufacturing cost can be reduced in the device configuration.

Also, in common with each claim, since the liquid and the gas are mixed before the swirling flow is generated, the cavitation can be effectively generated by uniforming the sizes of the generated bubbles. There is an effect that can be done.

Further, according to claims 2 and 3, in addition to further uniformizing the size of the bubbles generated in a saturated state or a supersaturated state, a uniform gas-liquid mixture is introduced by introducing the atmosphere without being influenced by gas pressure or the like. It is possible to perform the above, and it is possible to more effectively generate vapor cavitation.

According to claim 4, since the cavitation generator has the cylindrical shape, the conical portion, and the swirl guide portion, swirl flow is likely to occur, and the passage of the mixed liquid promotes the formation of a reduced pressure to further increase the cavitation. It can be effectively generated and has an effect of facilitating connection to a cleaning device or the like.

Further, according to the present invention, in addition to the generation of the cavitation, a jet flow is ejected from the nozzle, so that a difference between the pressure and the flow velocity of the mixed liquid that causes the cavitation is generated, and the pressure is rapidly reduced to super pressure. Cavitation can be generated.

Further, according to the fifth aspect, since micro bubbles can be mixed in the mixed liquid, there is an effect that cavitation can be generated more effectively.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a cavitation generation method and a cavitation generation device according to the present invention.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is a flow path diagram showing a cleaning device incorporating an embodiment of a method and a device for generating cavitation according to the present invention.

[Explanation of symbols]

 1 Mixer 8 Cavitation Generator 8a Cylinder 8b Body 8c Cone 8d Nozzle 8e Swirling Guide 8g Guide Surface A Liquid B Gas C, F Mixed Liquid E Jet Flow

Claims (5)

[Claims] 1. A method of generating cavitation in which a mixed liquid obtained by mixing a gas with a liquid is swirled, and the mixed liquid is jetted toward the downstream side from the swirling center of the mixed liquid to rapidly reduce the pressure. 2. The method for generating cavitation according to claim 1, wherein the gas of the mixed liquid is in a saturated state or a supersaturated state. 3. A mixer for mixing a liquid with a gas to form a mixed liquid, and a cavitation generator for feeding the mixed liquid to generate cavitation. The cavitation generator has a cylindrical body through which the mixed liquid flows. A device for generating cavitation, comprising a conical portion provided in a tapered outer shape toward the downstream side at the center of the tubular body, and a swirl guide portion provided between the tubular body and the conical portion for swirling the mixed liquid. 4. The cavitation generator according to claim 3, wherein a nozzle for injecting a jet flow is opened at the tapered tip of the conical portion. 5. The cavitation generator according to claim 4, wherein the mixer is a vortex pump.