JP2022105432A - Laminated venturi nozzle and microbubble liquid generation device - Google Patents

Abstract

To provide a laminated venturi nozzle which obtains microbubbles having a small bubble diameter and bubble diameter distribution.SOLUTION: A laminated venturi nozzle 10 has grooved blocks 12 formed with two of parallel groove-like venturi flow channel 20 and Y groove-like two-branched flow channel 22, non-grooved blocks 14, connection means 17 for connecting laminated blocks 16 in which a predetermined total number of the grooved blocks 12 and the non-grooved blocks 14 are laminated, and a supply block 18 having one supply flow channel 18A for supplying a gas mixed liquid mixed with gas by pressure dissolving to the laminated blocks 16, in which the laminated block 16 is formed with a plurality of tubular flow channels by laminating the grooved blocks 12 and the non-grooved blocks 14 so that the venturi flow channel 20 and the two-branched flow channel 22 are tubular flow channels, and does not generate bubbles on the supply flow channel from gas-liquid supply means 19 to the laminated block 16.SELECTED DRAWING: Figure 1

Description

The present invention relates to a laminated Venturi nozzle, a method for manufacturing the same, and a microbubble liquid generator, and more particularly to a technique for generating microbubbles by a Venturi structure.

In recent years, microbubble liquid generators that obtain microbubble liquid by blowing microbubbles (bubbles with a diameter of 1 to 100 μm) into a liquid such as water stored in a container have been used in industrial, chemical, medical, agricultural, fishery, etc. It is used in various fields.

For example, microbubbles have a cleaning action that can strongly remove oil stains and float and separate them, so they are used for photoresist removal in the semiconductor field, cleaning of semiconductor wafers, and oil-water separation in the wastewater treatment field. ing. In addition, since microbubbles have a bactericidal action that strongly decomposes bacteria and viruses, they are used for sterilization, sterilization, microbubble bathtubs, etc. in the medical and welfare fields.

Furthermore, due to the physiologically active action of microbubbles, fish and shellfish grow large and delicious, and it helps to promote the growth of plants in hydroponics. Therefore, in the fields of agriculture and fisheries, aquaculture, hydroponics, and microbial activity. It is used for conversion.

However, the existing micro-bubble liquid generator is expensive and difficult to apply to the fields of agriculture, fisheries or wastewater treatment.

In the microbubble liquid generation device, as a method for generating microbubbles, there are a pressure melting method, a shear flow method, a porous plate method, a fine needle method, a Venturi tube method and the like. Although these methods have advantages and disadvantages, the Venturi tube method has a relatively simple structure and can generate microbubbles without the need for a drive unit in the Venturi tube, so it is possible to reduce the cost of the equipment. It has the advantage of being present (for example, Patent Document 1).

The principle of generating microbubbles in the Venturi tube method is to pass a liquid (for example, water) mixed with gas (for example, air or ozone) through the thinnest throat part (also called the throat part) of the Venturi tube at a speed reaching the speed of sound. .. As a result, a shock wave is generated to cause bubble collapse, and fine bubbles are obtained on the downstream side of the throat portion.

The above-mentioned cleaning action, bactericidal action, and bioactive action of the microbubble liquid obtained by the microbubble liquid generator have the effect as the bubble diameter of the microbubble is smaller and the microbubble concentration in the microbubble liquid is larger. It tends to grow. Further, the smaller the variation in the bubble diameter distribution of the microbubbles, the greater the effect tends to be.
Further, there is Patent Document 2 as a bubble generator in which the number of Venturi tubes is increased.

Japanese Unexamined Patent Publication No. 2016-73939 Japanese Unexamined Patent Publication No. 2008-161831

By the way, when microbubbles are generated by the Venturi tube method, the smaller the cross-sectional area of the flow path of the throat portion of the Venturi tube, the more effectively the bubble collapse phenomenon and the like can be obtained to obtain microbubbles having a small bubble diameter.

However, the mechanism of bubble miniaturization in Venturi tubes has not been fully elucidated. That is, the fact is that it has not been fully elucidated how to design the Venturi tube in order to generate a large amount of microbubbles having a small bubble diameter and a small variation in the bubble diameter distribution.

For example, if the cross-sectional area of the flow path of the throat portion is reduced with a single Venturi tube, microbubbles having a small bubble diameter can be obtained, but the amount of bubbles generated is reduced. Therefore, if the microbubble liquid generator is configured with a single Venturi tube, the microbubble concentration in the microbubble liquid cannot be sufficiently obtained. On the contrary, if the microbubble liquid generation device is configured with a single Venturi tube having a large flow path cross-sectional area in the throat portion, the amount of bubbles generated increases, but microbubbles having a small bubble diameter cannot be obtained.

That is, in the case of a single Venturi tube, there is a problem that both obtaining microbubbles having a small bubble diameter and increasing the amount of bubbles generated cannot be satisfied. As a solution to this problem, it is conceivable to increase the number of Venturi pipes.

Patent Document 2 is a bubble generator in which the number of Venturi tubes is increased. Within the scope of claims of Patent Document 2, an inlet flow path having a throttle portion for reducing the pressure of a liquid in which a gas is dissolved and a disk-shaped shape connected to the end of the inlet flow path and coaxial with the inlet flow path are formed. A plurality of outlet flow paths (corresponding to Venturi flow paths) connected to the outer peripheral side of the distribution flow path and arranged around the axis of the distribution flow path are provided, and from each outlet flow path. A bubble generator is disclosed that discharges each liquid containing bubbles.

However, the bubble generator of Patent Document 2 in which the number of Venturi tubes is increased has the following problem.

(1) The flow path shape of the Venturi tube has a throat portion having the smallest flow path cross-sectional area between the flow path reducing portion in which the flow path cross-sectional area gradually shrinks and the flow path expanding portion in which the flow path cross-sectional area gradually expands. The shape. Therefore, in the method of manufacturing a plurality of Venturi tubes by hollowing out a plurality of holes in a block as in Patent Document 2, the Venturi flow path is manufactured with exactly the same shape and the same flow path cross-sectional area with high accuracy. Is difficult. If there are variations in the shape and cross-sectional area of the flow path of a plurality of venturi tubes, variations are likely to occur in the bubble diameter, bubble diameter distribution, and bubble generation amount of the microbubbles for each venturi tube.

(2) Further, in the case of Patent Document 2, an inlet flow path having a throttle portion for reducing the pressure of the liquid in which the gas is dissolved is connected to the end of the inlet flow path in front of the outlet flow path which is a Venturi flow path. It has a disc-shaped distribution channel that is coaxial with the inlet channel, and the cross-sectional area of the channel through which the liquid in which the gas is dissolved is once reduced at the inlet channel and then expanded at the distribution channel. Then, it flows into the outlet flow path (Venturi flow path). That is, if the structure is such that bubbles are generated at the inlet flow path, the distribution flow path, and the outlet flow path, the amount of bubbles generated in the outlet flow path, which is a Venturi tube capable of producing microbubbles, is controlled. Not only is it difficult to control, but it also has the disadvantage that the bubble diameter distribution is small and difficult to control.

The present invention has been made in view of such circumstances, and it is possible to obtain microbubbles having a small bubble diameter and bubble diameter distribution with a large amount of bubbles generated by using a Venturi structure that can be inexpensive in terms of equipment cost. It is an object of the present invention to provide a laminated Venturi nozzle capable of accurately controlling the bubble diameter distribution and the amount of bubbles generated in the Venturi flow path, a method for manufacturing the same, and a microbubble liquid generator.

The laminated Venturi nozzle of the present invention is a Venturi-structured nozzle for generating microbubbles in order to achieve the above object, and the flow path reduction gradually reduces the flow path cross-sectional area on the surface of a block whose both sides are flat. Two parallel groove-shaped venturi channels and two venturi flow paths having a throat portion with the smallest flow path cross-sectional area between the section and the flow path expansion section where the flow path cross-sectional area gradually expands. A grooved block formed so that the Y-groove-shaped two-branch flow paths that communicate with the entrance of the reduced portion are symmetrical, a plate-shaped grooveless block with flat sides, and a grooved block and a grooveless block. It has a connecting means for connecting the laminated blocks in which a predetermined total number of laminated blocks are connected, and a gas-liquid supply means for supplying the liquid for generating the microbubbles and the gas mixed with the liquid to the laminated blocks. In the block, a plurality of tubular flow paths are formed by laminating a grooved block and a grooveless block so that a groove-shaped venturi flow path and a Y-groove-shaped bifurcated flow path become a tubular flow path. At the same time, a fluid outlet and a fluid supply port of the tubular flow path are formed, and the flow path cross-sectional area shifts from reduction to expansion in the liquid and gas fluid supply route from the gas-liquid supply means to the laminated block. It is characterized by having no portion.
Further, the fluid supply route does not have the enlarged / reduced portion, so that the fluid supply route can be configured so as not to generate bubbles. Since the flow path supply route does not have an enlargement / reduction portion, it is impossible for bubbles to be generated from the enlargement / reduction portion.

Here, the predetermined total number of sheets means the total number of the number of grooves with grooves and the number of blocks without grooves constituting the laminated block, and the required number of blocks with grooves and the number of blocks without grooves according to the amount of bubbles generated by the laminated venturi nozzle. Determine the required number of blocks as appropriate.

Further, the liquid and gas fluid supply route from the gas-liquid supply means to the laminated block may be a component of the gas-liquid supply means, or may be a flow path connecting the gas-liquid supply means and the laminated block. It may be both the above-mentioned component and the above-mentioned flow path.

The shape of the grooved block and the grooveless block is preferably a quadrangle, but the shape is not limited to the quadrangle. The connecting means for connecting the grooved block and the grooveless block is preferably detachable, but is not limited to detachable, and a fixing means that cannot be detached once fixed can also be adopted.

According to the laminated Venturi nozzle of the present invention, the two parallel groove-shaped Venturi flow paths and the Y-groove-shaped two-branch flow path communicating with the inlets of the flow path reduction portions of the two Venturi flow paths are symmetrical. A configuration was adopted in which a predetermined total number of grooved blocks and non-grooved blocks formed so as to be formed were laminated to form a tubular Venturi flow path and a two-branch flow path.

This makes it possible to use a cutting method that facilitates high-precision machining to form a flow path. Therefore, since it does not depend on the material of the block, not only the manufacturing cost is low, but also the shape and the cross-sectional area of the flow path of the throat portion are less likely to vary even if the number of venturi flow paths is increased.

Further, the two venturis formed in the grooved block and one bifurcated flow path are formed so as to be symmetrical with respect to the axis of symmetry.

In addition, since the grooved block and the grooveless block constituting the laminated block can be detachably connected by the connecting means, the number of Venturi flow paths formed in the laminated block, in other words, the amount of air bubbles generated can be easily changed. Can be done.

With these configurations, it is possible to provide a laminated Venturi nozzle capable of obtaining microbubbles having a small bubble diameter and a small bubble diameter distribution with a large amount of bubbles generated by using a Venturi structure that can be inexpensive in terms of equipment cost.

Further, according to the laminated Venturi nozzle of the present invention, bubbles are not generated in the fluid supply route of liquid and gas from the gas-liquid supply means to the laminated block, so that the bubble diameter distribution of the microbubbles generated in the Venturi flow path is not generated. And the amount of bubbles generated can be controlled accurately.

According to the aspect of the laminated Venturi nozzle of the present invention, it is preferable that the fluid supply route does not have a reduction / expansion portion in which the cross-sectional area of the flow path shifts from reduction to expansion. In this way, the fluid supply route of the liquid and gas from the gas-liquid supply means to the laminated block does not have a shrinking / expanding portion where the cross-sectional area of the flow path shifts from shrinking to expanding, so that the front stage of the Venturi flow path Can prevent bubbles from being generated.

By the way, as in Patent Document 2, if the fluid supply route of the liquid and gas in the front stage of the Venturi flow path has a reduced / enlarged portion in which the cross-sectional area of the channel shifts from shrinking to expanding, bubbles are generated in the shrinking / expanding portion. , The amount of bubbles generated in the Venturi flow path fluctuates.

According to the aspect of the laminated Venturi nozzle of the present invention, the gas-liquid supply means supplies the laminated block with one gas-liquid supply flow path for supplying a gas mixed liquid in which a gas is mixed with a liquid by pressure dissolution. It is preferably a block.

In this way, by supplying a gas mixture in which a gas is pressurized and dissolved in a liquid to a plurality of Venturi flow paths formed in a laminated block, the gas-liquid volume flow rate ratio (β) for each Venturi flow path varies. Is less likely to occur. Further, since the gas mixed liquid is supplied to the laminated block from the supply block having one supply flow path, the inlet flow rate (inlet pressure) of the plurality of Venturi flow paths is less likely to vary.

According to the aspect of the laminated venturi nozzle of the present invention, the laminated block is formed in the laminated direction of the laminated block, and is formed on the surface of the grooved block and the gas supply hole for communicating the grooved block and the non-grooved block. A groove-shaped gas supply groove having one end communicating with the throat portion of the groove-shaped venturi flow path and the other end communicating with the gas supply hole, and the gas / liquid supply means is a fluid supply port of the laminated block. It has a liquid supply flow path for supplying a liquid to the stacking block and a gas supply flow path for supplying a gas to a gas supply hole formed in the laminated block. It is preferable to separately supply the throat portion of the venturi flow path formed in the laminated block.

In the embodiment of the present invention, the liquid for generating microbubbles is supplied to the fluid supply port of the laminated block, and the gas is separately supplied to the throat portion of the Venturi flow path formed in the laminated block, and the grooved block. It has a gas supply structure because it is a laminated block in which and a grooveless block are laminated. That is, a gas supply hole is formed in the laminated block in the stacking direction of the grooved block and the grooveless block in which a predetermined total number of layers are laminated, and a venturi flow having a groove-like end on the surface of the grooved block. A groove-shaped gas supply groove was formed so as to communicate with the throat portion of the road and the other end to communicate with the gas supply hole. The gas-liquid supply means is configured to include a liquid supply flow path for supplying liquid to the fluid supply port of the laminated block and a gas supply flow path for supplying gas to the gas supply hole formed in the laminated block. I made it.

In this way, by directly supplying the gas to the throat portion of the Venturi flow path, even in the case of a corrosive gas, for example, the equipment of the gas-liquid supply means is not corroded.

According to the aspect of the laminated Venturi nozzle of the present invention, it is preferable that the cross-sectional shape of the tubular Venturi flow path and the bifurcated flow path formed in the laminated block is a square or a rectangular rectangle. As a result, when forming a groove in a block with a groove by cutting, it is easier to cut with higher accuracy than other groove shapes such as a semicircle.

According to the aspect of the laminated Venturi nozzle of the present invention, the plurality of tubular flow paths formed in the laminated block are formed so as to be substantially located on the circumference about the axis of the supply flow path in the supply block. Is preferable. Here, the supply flow path in the supply block means a part of the flow path provided in the fluid supply route of the liquid and gas from the gas-liquid supply means to the laminated block.

As a result, the plurality of tubular flow paths formed in the laminated block have a symmetric positional relationship with respect to the axis of one supply flow path of the supply block, and thus a plurality of bifurcated flows from the supply flow path. When the gas mixed liquid is supplied to a plurality of Venturi flow paths via the passage, the gas mixed liquid can be supplied more evenly.

According to the aspect of the laminated Venturi nozzle of the present invention, it is preferable that the number of each of the grooved block and the grooveless block in the predetermined total number of laminated blocks is set by the number of formed venturi flow paths. As a result, the amount of bubbles generated can be easily changed by simply changing the number of grooved blocks and the number of non-grooved blocks constituting the laminated block.

According to the aspect of the laminated venturi nozzle of the present invention, a fitting notch for fitting and connecting the supply block to the laminated block is formed on the block side on the side where the fluid supply port of the laminated block is formed. Is preferable. This enables accurate positioning connection between the laminated block and the supply block. Therefore, it is possible to perform positioning with high accuracy so that the plurality of tubular flow paths formed in the laminated block are substantially positioned on the circumference centered on the axis of one supply flow path of the supply block. ..

According to the aspect of the laminated venturi nozzle of the present invention, in the laminating of the grooved block and the grooveless block constituting the laminated block, the front surface and the back surface of the grooved blocks or the front surface and the grooveless block of the grooved block are overlapped. The flow path cross-sectional area of the tubular flow path can be changed depending on whether the blocks are aligned or the surfaces of the grooved blocks are overlapped with each other. As a result, the number of Venturi flow paths and the flow path cross-sectional area of the Venturi flow path, particularly the flow path cross-sectional area of the throat portion, can be changed as necessary even though the laminated blocks have the same number of layers.

According to the aspect of the laminated Venturi nozzle of the present invention, the laminated block has a three-dimensional structure in which four or more Venturi flow paths are formed by laminating three or more layers according to the amount of microbubbles generated. preferable. In the case of two-layer lamination, it is difficult to obtain the effect of flexible number of venturis, which is a feature of the present invention.

According to the aspect of the laminated Venturi nozzle of the present invention, in the Venturi flow path, the rectangular vertical width and the horizontal width of the throat portion are 1.0 mm or more and 5.0 mm or less, and the length is 1.0 mm or more and 5.0 mm or less. It is preferable to have. It is not only difficult to cut the width of the throat portion to less than 1.0 mm, but also foreign matter such as dust is likely to be clogged in the throat portion. Further, when the width of the throat portion exceeds 5.0 mm, there is a balance with the flow rate of the gas mixed liquid, but the choked flow in which the flow velocity exceeds the speed of sound is less likely to occur.

Further, the length of the throat portion should be as short as possible, but it is difficult to make it less than 1.0 mm in terms of cutting. Further, if it exceeds 5.0 mm, pressure recovery (pressure rise) in the flow path expansion portion is less likely to occur, and bubbles are less likely to collapse.

The method for manufacturing a laminated Venturi nozzle of the present invention is a method for manufacturing a Venturi-structured nozzle for generating microbubbles. Two groove-shaped Venturi flow paths having a flow path expansion section in which the flow path cross-sectional area gradually expands following the path reduction section, and a Y groove communicating with the inlet of the flow path reduction section of the two Venturi flow paths, respectively. A grooved block forming step that forms a grooved block formed so that the two-branched flow path is symmetrical, and a plate-like plate that is formed to the same size as the grooved block and is flat on both sides. A plurality of grooved blocks and grooveless blocks are laminated so that the grooveless block forming step of forming the grooveless block and the grooved Venturi flow path and the grooved bifurcated flow path become a tubular flow path. A laminated block forming step of forming a tubular flow path and forming a fluid outlet of a Venturi flow path and a fluid supply port of a two-branch flow path, and a grooved block and a grooveless block of the laminated block. A reduction / enlargement part in which the cross-sectional area of the flow path shifts from reduction to expansion while supplying a gas mixture liquid in which gas is pressurized and dissolved to a plurality of fluid supply ports formed in a laminated block and a connection step for detachably connecting the two. It is characterized by comprising a supply block connecting step of connecting a supply block having one supply flow path which does not have.

By implementing the method for manufacturing a laminated Venturi nozzle of the present invention, the above-mentioned laminated Venturi nozzle can be manufactured.

According to the aspect of the method for manufacturing a laminated Venturi nozzle of the present invention, in the grooved block forming step, it is preferable to form a groove-shaped Venturi flow path and a groove-shaped bifurcated flow path by cutting. By forming by cutting, it is possible to form a groove of a Venturi flow path or a two-branch flow path with high accuracy regardless of the material of the block.

The microbubble liquid generator of the present invention is a microbubble liquid generator that generates a microbubble liquid by blowing microbubbles into a liquid, and includes a container for storing the liquid and a circulation pipe for extracting the liquid from the container and returning it to the container again. , A circulation pump installed in the circulation pipe, a pressure-dissolving device installed on the upstream side of the circulation pump of the circulation pipe to pressurize and dissolve gas in the liquid flowing through the circulation pipe, and a gas supply pipe to the pressure-dissolving device. It is characterized by being provided with an air supply device for supplying gas via the above and the laminated venturi nozzle connected to a return position of a circulation pipe.

According to the microbubble liquid generation device of the present invention, since the laminated venturi nozzle of the present invention is used, it is possible to generate a microbubble liquid in which a large amount of microbubbles having a small bubble diameter and bubble diameter distribution are blown into the liquid. It is possible to accurately control the bubble diameter distribution and the amount of bubbles generated in the microbubbles generated in the flow path.

The laminated Venturi nozzle of the present invention is a Venturi structure nozzle for generating microbubbles in order to achieve the above object, and the flow path reduction gradually reduces the flow path cross-sectional area on the surface of a block whose both sides are flat. A grooved block in which at least one groove-shaped Venturi flow path having a throat portion having the smallest flow path cross-sectional area is formed between the portion and the flow path expansion portion in which the flow path cross-sectional area gradually expands, and both sides A connecting means for connecting a flat plate-shaped non-grooved block, a laminated block in which a grooved block and a non-grooved block are laminated, and a liquid for generating a microbubble in the Venturi flow path formed in the laminated block. It has a gas-liquid supply means for supplying a gas to be mixed with a liquid, and the laminated block has a grooved block and a grooveless block so that a grooved Venturi flow path becomes a tubular flow path, and microbubbles are generated. It has a three-dimensional structure in which two or more Venturi flow paths are formed by stacking three or more layers according to the amount, and a fluid outlet and a fluid supply port of the tubular flow path are formed and laminated from the gas-liquid supply means. It is characterized in that no bubbles are generated in the liquid supply route of the liquid reaching the block and the gas.

The laminated Venturi nozzle of the present invention is a case where a grooved block in which at least one groove-shaped Venturi flow path is formed and a grooveless block are laminated to form a laminated block. The laminated block has two or more venturis by laminating three or more layers of a grooved block and a grooveless block according to the amount of microbubbles generated so that the grooved venturi flow path becomes a tubular flow path. It has a three-dimensional structure in which the flow path is formed, and the fluid outlet and the fluid supply port of the tubular flow path are formed. Furthermore, bubbles are not generated in the liquid and gas fluid supply routes from the gas-liquid supply means to the laminated block.

As a result, microbubbles with a small bubble diameter and bubble diameter distribution can be obtained with a large amount of bubbles generated by using a Venturi structure that can be inexpensive in terms of equipment cost, and the bubble diameter of the microbubbles generated in the Venturi flow path. It is possible to provide a laminated Venturi nozzle capable of accurately controlling the distribution and the amount of bubbles generated.

In the aspect of the laminated Venturi nozzle of the present invention, it is preferable that the fluid supply route does not have a shrinking / expanding portion in which the cross-sectional area of the flow path shifts from shrinking to expanding. In this way, the fluid supply route of the liquid and gas from the gas-liquid supply means to the laminated block does not have a shrinking / expanding portion where the cross-sectional area of the flow path shifts from shrinking to expanding, so that the front stage of the Venturi flow path Can prevent bubbles from being generated.

According to the laminated Venturi nozzle of the present invention and the manufacturing method thereof, it is possible to obtain microbubbles having a small bubble diameter and a small variation in the bubble diameter distribution with a large amount of bubbles generated in a Venturi structure capable of low cost in terms of equipment cost. It is an object of the present invention to provide a laminated Venturi nozzle capable of accurately controlling the bubble diameter distribution and the amount of bubbles generated in the microbubbles generated in the Venturi flow path, and a method for manufacturing the same.

Further, according to the microbubble liquid generation device of the present invention, it is possible to generate a microbubble liquid in which a large amount of microbubbles having a small bubble diameter and bubble diameter distribution are blown into the liquid.

Explanatory drawing explaining the whole structure of the laminated Venturi nozzle of 1st Embodiment of this invention. Perspective view of the grooved block Perspective view of ungrooved block Perspective view of supply block Assembly drawing of laminated blocks Perspective view connecting the supply block to the laminated block Explanatory drawing of four Venturi flow paths in another aspect of the laminated Venturi nozzle of the present invention. Explanatory drawing of two Venturi flow paths in another aspect of the laminated Venturi nozzle of the present invention. Explanatory drawing when the flow path cross-sectional area of a throat portion is expanded by another aspect of the laminated Venturi nozzle of this invention. Explanatory diagram of the mechanism that generates microbubbles in the Venturi structure Explanatory drawing of a laminated Venturi nozzle tested for an appropriate flow path cross-sectional area of the throat Explanatory drawing of the laminated Venturi nozzle used for control 1 of verification test 1 Graph showing test results when the gas-liquid volume flow rate ratio of verification test 1 is 0.02 Graph showing test results when the gas-liquid volume flow rate ratio of verification test 1 is 0.007 Table of number distribution of bubble diameter in verification test 1 A graph showing the test results when the gas-liquid volume flow rate ratio of the verification test 2 is 0.013. A graph showing the test results when the gas-liquid volume flow rate ratio of the verification test 2 is 0.004. Table of number distribution of bubble diameter in verification test 2 A graph investigating the effect of the relationship between the cross-sectional area of the flow path of the throat and the flow rate of the gas mixture on the bubble diameter. Explanatory drawing explaining the whole structure of the microbubble liquid generator Explanatory drawing of laminated Venturi nozzle when gas is directly supplied to Venturi flow path Perspective view of a grooved block when gas is directly supplied to the Venturi flow path. Perspective view of a grooveless block when supplying gas directly to the Venturi flow path A perspective view of another aspect of the grooved block when the gas is directly supplied to the Venturi flow path. Explanatory drawing explaining the whole structure of the laminated Venturi nozzle of the 2nd Embodiment of this invention.

Hereinafter, a preferred embodiment of the laminated Venturi nozzle according to the present invention, a method for manufacturing the same, and a microbubble liquid generator will be described in detail with reference to the accompanying drawings.

[First Embodiment of Laminated Venturi Nozzle]
In the first embodiment of the laminated Venturi nozzle, when the grooved block and the grooveless block are laminated to form a three-dimensional structure of the laminated block, if the venturi flow path is only in the vertical direction (stacking direction) of the three-dimensional structure. By forming it in the lateral direction as well, two parallel Venturi flow paths are formed in the grooved block so that the amount of microbubbles generated can be increased.

FIG. 1A is a plan view of the laminated Venturi nozzle according to the first embodiment of the present invention from above, and FIG. 1B is a front view of the laminated Venturi nozzle from the front side (the side where the fluid is ejected). It is a figure.

2 is a perspective view of the grooved block, and FIG. 3 is a perspective view of the grooveless block. FIG. 4 is a perspective view of the supply block.

As shown in FIG. 1, in the laminated venturi nozzle 10 of the embodiment of the present invention, mainly a grooved block 12, a grooveless block 14, a grooved block 12 and a grooveless block 14 are laminated in a predetermined total number of sheets. The laminated block 16, the connecting means 17 for detachably connecting the laminated blocks 16, and the gas-liquid supply means 19 for supplying the liquid for generating microbubbles to the laminated block 16 and the gas mixed with the liquid (FIG. 20). (See), and is configured not to generate bubbles in the liquid and gas fluid supply routes from the gas-liquid supply means 19 to the laminated block 16.

Then, in the laminated Venturi nozzle 10 of the first embodiment of the present invention, as a component of the gas-liquid supply means 19, a gas mixed liquid in which a gas is mixed with a liquid by pressure dissolution is supplied to the laminated block 16. The case where the supply block 18 having one supply flow path 18A is provided will be described below.

Here, the predetermined total number of sheets means the total number of the number of grooved blocks 12 and the number of non-grooved blocks 14 constituting the laminated block 16, and the amount of bubbles generated in the laminated venturi nozzle 10 (that is, the number of venturi flow paths). The required number of grooved blocks 12 and the required number of non-grooved blocks 14 are appropriately determined accordingly.

Then, in the laminated venturi nozzle 10 of the first embodiment, as shown in FIG. 1 (B), a case of a four-layer structure of four blocks as a predetermined total number of laminated blocks 16 will be described. The predetermined total number of laminated blocks 16 is not limited to four, and can be changed according to the amount of microbubbles generated by the laminated venturi nozzle 10.

Further, in the first embodiment, the bolt 17A and the nut 17B (see FIG. 5) will be described as examples of the connecting means 17. Further, in the following description, the front side and the rear side of the block or the flow path are referred to as the front side when viewed from the flow direction of the gas mixture, and the upstream side as the rear side.

As shown in FIG. 2, the grooved block 12 has a channel reducing portion 20A in which the cross-sectional area of the flow path is gradually reduced and a flow path in which the cross-sectional area of the flow path is gradually expanded on a plate-shaped block surface having flat and rectangular surfaces on both sides. Two parallel groove-shaped venturi flow paths 20 and 20 having a throat portion 20C having the smallest flow path cross-sectional area are formed between the enlargement portion 20B and the throat portion 20C. Further, a Y-groove-shaped bifurcated flow path 22 communicating with the inlet 20E (synonymous with the inlet of the Venturi flow path 20) of the flow path reduction portion 20A of the two Venturi flow paths 20 is formed.

The two-branch flow path 22 has a semi-ring cylinder shape or a U-shape as shown in FIG. 1 so that turbulence does not occur in the flow of the fluid branching from the fluid supply port 22A to the two Venturi flow paths 20. Is preferable. If the two-branch flow path 22 has an angular portion or a stepped portion, turbulent flow is generated in that portion, and bubbles are likely to be generated in a portion other than the Venturi flow path 20. The reason why it is not preferable for the present invention that bubbles are generated in a portion other than the Venturi flow path 20 will be described in the portion (Structure F) described below.

The groove shape of the groove-shaped Venturi flow path 20 formed in the grooved block 12 is preferably a square or a rectangular rectangle. When the Venturi flow path 20 is formed by cutting, the flow path cross-sectional area is the largest between the flow path reduction portion 20A in which the flow path cross-sectional area gradually shrinks and the flow path expansion portion 20B in which the flow path cross-sectional area gradually expands. It is possible to perform cutting with higher accuracy by forming the venturi flow path 20 having a small throat portion 20C in a rectangular groove shape than in forming a groove shape other than the rectangular shape.

Further, the front end of the venturi flow path 20 is opened to the front side 12A of the grooved block 12 to form the fluid ejection port 20D, and the rear end of the two-branch flow path 22 is on the rear side 12B of the grooved block 12. It is opened to form the fluid supply port 22A. Then, as shown in FIG. 1, the two parallel Venturi flow paths 20 and the one bifurcated flow path 22 communicating with them are formed so as to be symmetrical with respect to the axis of symmetry N.

Further, as shown in FIG. 2, bolt holes 24, 24 ... Are formed at three locations of the grooved block 12, and the supply block 18 is fixed to the laminated block 16 on the back surface side of the grooved block 12. A screw hole 26 (a hole in which a female screw is engraved and does not penetrate) is formed. Further, a fitting notch 28 into which the supply block 18 is fitted is formed at the central portion of the rear end of the grooved block 12 in the block width direction.

As shown in FIG. 3, the grooveless block 14 is formed to have the same size as the grooved block 12, and is formed into a quadrangular plate shape having flat sides on both sides. Further, bolt holes 24 are formed at three positions of the grooveless block 14 at the same positions as the grooved block 12. That is, when the laminated block 16 is formed, the bolt holes 24 of the grooved block 12 and the grooveless block 14 communicate with each other. Further, on one side of the grooveless block 14, a screw hole 26 (a non-penetrating hole in which a female screw is engraved) for fixing the supply block 18 to the laminated block 16 is formed as in the grooved block 12. .. Further, a fitting notch 28 into which the supply block 18 is fitted is formed in the central portion of the rear end of the grooveless block 14 in the block width direction, similarly to the grooved block 12. That is, when the laminated block 16 is formed, the fitting notch 28 between the grooved block 12 and the grooveless block 14 matches.

As shown in FIG. 4, the supply block 18 is a pair of upper and lower surfaces of the laminated block 16 that are fitted to each other at the upper and lower positions of a substantially square block through which one circular tubular supply flow path 18A penetrates. The overhanging portion 30 is formed in an overhanging U-shape. The upper overhanging portion is referred to as an upper overhanging portion 30A, and the lower overhanging portion is referred to as a lower overhanging portion 30B. Further, through holes 34, 34 ... Through which the screws 32, 32 ... Screwed into the screw holes 26 described above penetrate are formed in the upper overhanging portion 30A and the lower overhanging portion 30B. Further, the width P of the supply block 18 is formed so as to be fitted in the above-mentioned fitting notch 28.

As described above, one of the major features of the laminated venturi nozzle 10 of the present invention is that bubbles are not generated in the liquid and gas fluid supply routes from the gas / liquid supply means 19 to the laminated block 16. Specifically, it is required that the liquid and gas fluid supply route from the gas-liquid supply means 19 to the laminated block 16 does not have a reduction / expansion portion in which the cross-sectional area of the flow path shifts from reduction to expansion.

The liquid and gas fluid supply route from the gas / liquid supply means 19 to the laminated block 16 may be a component of the gas / liquid supply means 19, or connects the gas / liquid supply means 19 and the laminated block 16. It may be a flow path, and may be both the above-mentioned component and the above-mentioned flow path. Further, the fluid supply route is not limited to a flow path such as piping, but also includes equipment such as a pump 44 (see FIG. 20) for flowing a fluid.

Therefore, when the supply block 18 is a flow path connecting the gas-liquid supply means 19 and the laminated block 16, the flow path cross-sectional area of the circular tubular supply flow path 18A of the supply block 18 also shifts from reduction to expansion. It is required not to have an enlarged part. Further, the pump 44 for flowing the fluid is preferably a pump that does not generate cavitation.
Next, a method of manufacturing the laminated venturi nozzle 10 according to the first embodiment will be described.

[Method of manufacturing the laminated Venturi nozzle of the first embodiment]
The method for manufacturing the laminated venturi nozzle 10 of the first embodiment is mainly composed of a grooved block forming step, a grooveless block forming step, a laminated block forming step, a connecting step, and a supply block connecting step. ..

In the grooved block forming step, the grooved block 12 shown in FIG. 2 is manufactured by cutting. For example, using a machining center, a cutting process is performed on the surface of a quadrangular plate-shaped block whose both sides are flat so that the groove-shaped Venturi flow path 20 and the Y-groove-shaped bifurcated flow path 22 are symmetrical. Further, the above-mentioned fitting notch 28, bolt hole 24, and the like are formed.

In the grooveless block forming step, the grooveless block 14 shown in FIG. 3 is manufactured by cutting. For example, using a machining center, it is formed to have the same size as the grooved block 12.

In the laminated block forming step, as shown in FIG. 5, a predetermined total number of grooved blocks 12 and grooveless blocks 14 are laminated. That is, the front surface on which the groove of the grooved block 12 located at the bottom is formed and the back surface on which the groove of the grooved block 12 located second from the bottom is not formed are overlapped. Next, the front surface on which the groove of the grooved block 12 located second from the bottom is formed and the back surface on which the groove of the grooved block 12 located third from the bottom is not formed are overlapped. Finally, the grooved surface of the grooved block 12 located third from the bottom and the grooveless block 14 are superposed.

As a result, as shown in FIG. 1, fluid supply ports 22A (3 pieces) to the bifurcated flow path 22 and fluid ejection ports 20D (6 pieces) from the Venturi flow path 20 are opened at both ends of the tubular flow path. A laminated block 16 having a four-layer structure is formed. Therefore, the Venturi flow path 20 can be multi-layered with a simple configuration in which the grooved block 12 and the grooveless block 14 are simply laminated.

In the connecting step, the formed laminated block 16 is detachably connected with a bolt 17A and a nut 17B. That is, as shown in FIG. 5, the bolt 17A is inserted into the bolt holes 24, 24 ... Of the three grooved blocks 12 constituting the laminated block 16 and the one ungrooved block 14, and formed at the tip of the bolt. The laminated block 16 is detachably fixed by screwing the female screw of the nut 17B into the male screw.

In the supply block connecting step, as shown in FIG. 6, the supply block 18 is connected to the rear end of the laminated block 16. That is, in order to connect the supply block 18 to the laminated block 16, the supply block 18 is laminated so that the upper overhanging portion 30A and the lower overhanging portion 30B of the supply block 18 sandwich the upper surface and the lower surface of the laminated block 16. It is inserted into the fitting notch 28 of 16. As a result, the supply block 18 is fitted to the laminated block 16. In this state, the four screws 32 are screwed into the screw holes 26 of the laminated block 16 through the through holes 34 of the supply block 18. As a result, the supply block 18 can be connected and fixed to the laminated block 16 in a state of being accurately positioned.

Therefore, when the supply block 18 is connected to the laminated block 16, a plurality of tubular flow paths (six Venturi flow paths and three bifurcated flow paths communicating with the six venturi flow paths) formed in the laminated block 16 are supplied. If the block 18 is designed in advance so as to be substantially located on the circumference centered on the axis M of the supply flow path 18A, a plurality of tubular flow paths are thin with respect to the axis M of the supply flow path 18A. It can be arranged to be metric.

In FIG. 1B, six fluid outlets 20D are arranged by arranging six fluid outlets 20D of the Venturi flow path on the circumference centered on the axis M of the supply channel 18A. It shows that they are arranged at substantially equidistant distances F around the axis M.
As a result, when the gas mixture is supplied from one supply flow path 18A of the supply block 18 to the six Venturi flow paths 20 of the laminated block 16, the gas mixture can be supplied more evenly. Therefore, when the Venturi flow paths 20 are mulched, the gas mixture can be uniformly and stably supplied to each Venturi flow path 20.

By each of the above steps, the laminated venturi nozzle 10 according to the first embodiment of the present invention can be manufactured. A pipe 36 for supplying the gas mixed liquid to the supply block 18 is connected to the supply block 18 of the manufactured laminated venturi nozzle 10. A male screw 36A is engraved at the tip of the pipe 36, and a female screw 18B to be screwed into the male screw 36A of the pipe 36 is engraved on the inner surface of the circular tubular supply flow path 18A of the supply block 18.

7 to 9 show another aspect of the laminated Venturi nozzle 10 in which the number of Venturi flow paths 20 formed in the laminated block 16 having a four-layer structure and the cross-sectional area of the flow path of the Venturi flow path 20 are changed.

In addition, (B) of FIGS. 7 to 9 is shown sideways in order to match the correspondence with the Venturi flow path 20 of (A), but the upper side of (A) is the lower side on the right side of (B). The side is on the left. Therefore, the case where the grooved block 12 and the grooveless block 14 are laminated from the left side (lower side) to the right side (upper side) is described. The same applies to FIGS. 1, 11 and 12.

FIG. 7 shows a case where four Venturi flow paths 20 having the same flow path cross-sectional area as in FIG. 1 are formed in the laminated block 16. FIG. 7A is a plan view of the laminated venturi nozzle 10 as viewed from above, and FIG. 7B is a front view of the laminated venturi nozzle 10 as viewed from the front side.

As shown in FIG. 7B, the laminated block 16 having four venturi flow paths 20 has a grooveless block 14, a grooved block 12, a grooveless block 14, and a grooved block 12 from the left side (lower side). It is formed by laminating in the order of. That is, the laminated block 16 having the four Venturi flow paths 20 is composed of two grooved blocks 12 and two grooveless blocks 14, although the predetermined total number of the laminated blocks 16 is the same as that in FIG. ..

FIG. 8 shows a case where two Venturi flow paths 20 having the same flow path cross-sectional area as in FIG. 1 are formed on the laminated block 16. FIG. 8A is a plan view of the laminated venturi nozzle 10 as viewed from above, and FIG. 8B is a front view of the laminated venturi nozzle 10 as viewed from the front side.

As shown in FIG. 8B, the laminated block 16 having two Venturi flow paths 20 has a grooveless block 14, a grooveless block 14, a grooved block 12, and a grooveless block 14 from the left side (lower side). It is formed by laminating in the order of. That is, the laminated block 16 having the two Venturi flow paths 20 is composed of one grooved block 12 and three grooveless blocks 14, although the predetermined total number of the laminated blocks 16 is the same as that in FIG. ..

FIG. 9 shows a laminated Venturi nozzle 10 having a four-layer structure having two Venturi flow paths 20, but it is a case where it is desired to make the flow path cross-sectional area of the Venturi flow path 20 larger than that in FIG. As shown in FIG. 9B, the laminated block 16 having two Venturi flow paths 20 having a larger flow path cross-sectional area than FIG. 8 has a grooveless block 14 and a grooved block 12 from the left side (lower side). , The grooved block 12 and the non-grooved block 14 are laminated in this order, and can be formed by superimposing the surfaces on which the grooves of the two grooved blocks 12 are formed.

As shown in FIGS. 7 to 9, in the lamination of the grooved block 12 and the grooveless block 14 constituting the laminated block 16, the front surface and the back surface of the grooved blocks 12 or the front surface and the grooveless block of the grooved block 12 are formed. The number of venturi flow paths 20 formed in the laminated block 16 and the cross-sectional area of the flow paths can be changed depending on whether the 14 is overlapped or the surfaces of the grooved blocks 12 are overlapped with each other.

In this way, by changing the combination method of the grooved block 12 and the grooveless block 14 constituting the laminated block 16 and changing the flow path cross-sectional area of the venturi flow path 20, the throat having a great influence on the generation of microbubbles. The cross-sectional area of the flow path of the portion 20C can be easily changed.

Further, also in the case of the laminated venturi nozzle 10 of FIGS. 7 to 9, the supply block 18 is fitted in a state of being positioned on the laminated block by forming a four-layer structure without changing the number of layers of the laminated block 16. Can be done. As a result, when the gas mixture is supplied from one supply flow path 18A of the supply block 18 to the plurality of Venturi flow paths 20 of the laminated block 16, the gas mixture can be supplied more evenly.

Although the present embodiment has been described by forming the laminated block 16 into a four-layer structure, in this case, the maximum number of six venturi flow paths 20 is reached. Therefore, if it is desired to further increase the number of Venturi flow paths 20, it is necessary to increase the number of layers. Also in this case, a plurality of tubular flow paths (Venturi flow path 20 and the bifurcated flow path 22 communicating with the venturi flow path 20) are substantially located on the circumference of the supply flow path 18A of the supply block 18 about the axis M. It is preferable to do so. Therefore, the diameter of the supply flow path 18A formed in the supply block 18, the distance between the upper overhanging portion 30A and the lower overhanging portion 30B, the distance between the two parallel Venturi flow paths 20 formed in the grooved block 12, and the like are also appropriate. Need to be adjusted.

The laminated venturi nozzle 10 of the first embodiment of the present invention configured as described above has the following configurations A to F.
(Structure A) The Venturi flow path 20 is a tubular flow path (Venturi flow path) in which a groove is formed on the surface of a plate-shaped block whose both sides are flat and square, and another block is laminated to close the opening surface of the groove. 20 and 2 branch flow paths 22). That is, a groove that becomes the Venturi flow path 20 and the two-branch flow path 22 is formed by flat surface processing capable of high-precision machining, and a plurality of Venturi flow paths 20 and the two-branch flow path 22 are formed by a simple method of laminating blocks. I tried to form a three-dimensional structure with.

As described above, in the formation of the Venturi flow path 20 and the two-branch flow path 22, by adopting the method of forming a groove on the block surface, the Venturi flow path 20 and the two-branch flow path 22 can be formed by cutting. As a result, since it does not depend on the material of the block, various materials such as resin-based materials and metal-based materials can be used, and the manufacturing cost can be reduced. Further, if a fluororesin such as PTFE is used as a material, a gas mixture of a strong acid or a strong alkali can be handled.

Further, by forming the Venturi flow path 20 and the two-branch flow path 22 by cutting, for example, a Venturi flow path formed by forming a flow path hole in a Venturi tube or a block formed by winding a metal plate into a tubular shape. The shape of the flow path and the cross-sectional area of the flow path can be formed with high accuracy. In particular, if the cutting of the block surface is performed by an NC (Numerical Control) cutting machine such as a machining center, a plurality of uniform Venturi flow paths can be formed with high accuracy. As a result, even if a plurality of Venturi flow paths 20 having a small flow path cross-sectional area of the throat portion 20C are manufactured in order to generate microbubbles having a small bubble diameter, the shape and flow path cross-sectional area of each Venturi flow path 20 vary. Can be prevented. As a result, it is considered that the bubble diameter of the microbubbles can be reduced, and the bubble diameter distribution and the amount of bubbles generated for each Venturi flow path 20 are unlikely to vary.

(Structure B) The number of groove-shaped flow paths formed on the surface of the grooved block 12 is two, and the inlets of the flow path reduction portions 20A of the two parallel groove-shaped venturi flow paths 20 and the two venturi flow paths 20. The Y-groove-shaped bifurcated flow path 22 communicating with 20E is configured to have a symmetrical symmetry. As a result, the flow rate, the flow velocity, and the like of the gas mixed liquid flowing through the two Venturi flow paths 20 are equalized. As a result, it is considered that the bubble diameter of the microbubbles can be reduced, and the bubble diameter distribution and the amount of bubbles generated in each Venturi flow path are unlikely to vary. In this case, the larger the number of flow paths formed on the block surface, the more difficult it is to make it symmetric, and the more difficult it is to equalize the flow rate, flow rate, etc. of the gas mixture flowing through the flow paths. It is considered appropriate to form two Venturi flow paths 20.

(Structure C) The number of venturi flow paths 20 can be changed by laminating a predetermined total number of grooved blocks 12 and non-grooved blocks 14 to form a laminated block 16, and the amount of microbubbles generated is small. We have made it easy to handle from to large flow rates. In other words, the number of venturi flow paths 20 can be changed extremely easily by simply stacking the grooved block 12 and the grooveless block 14 to assemble the three-dimensional structure of the laminated block 16 according to the desired amount of microbubbles generated. I did it. This makes it possible to obtain a flexible effect on the number of Venturi flow paths.

The number of laminated blocks 16 is more preferably a three-dimensional structure in which four or more Venturi flow paths 20 are formed by stacking three or more layers according to the amount of microbubbles generated. In the case of two-layer stacking, it is difficult to obtain the above-mentioned flexible effect of the number of Venturi flow paths.

(Structure D) The gas mixture is supplied to the fluid supply ports 22A of the plurality of bifurcated flow paths 22 formed in the laminated block 16 by one supply flow path 18A. As a result, the gas mixed liquid is introduced into the laminated block 16 from one supply flow path 18A, and then is evenly shunted inside the laminated block 16 having the symmetric bifurcated flow path 22. Therefore, the inlet flow rate (inlet pressure) for each of the plurality of Venturi flow paths 20 is less likely to vary. As a result, it is considered that the bubble diameter of the microbubbles can be reduced, and the bubble diameter distribution and the amount of bubbles generated for each Venturi flow path 20 are unlikely to vary.

(Structure E) In the generation of microbubbles having a Venturi structure, a gas can be mixed with the liquid flowing through the Venturi flow path 20 at the throat portion (also referred to as “throat portion”). However, as in the present invention, by supplying the laminated block 16 with a gas mixture in which a gas is previously dissolved and mixed in the liquid by pressure dissolution, the gas-liquid volume flow rate ratio (β) for each of the plurality of Venturi flow paths 20 Is less likely to vary. As a result, it is considered that the bubble diameter of the microbubbles can be reduced, and the bubble diameter distribution and the amount of bubbles generated for each Venturi flow path 20 are unlikely to vary. The gas-liquid volume flow rate ratio (β) will be described later.

(Structure F) The liquid and gas fluid supply routes from the gas-liquid supply means 19 to the laminated block 16 do not generate bubbles. Specifically, as described above, the fluid supply route of the liquid and gas from the gas-liquid supply means 19 to the laminated block 16 does not have a reduction / expansion portion in which the cross-sectional area of the flow path shifts from reduction to expansion. did.

The above configurations A to E are components that make it difficult for the bubble diameter distribution and the amount of bubble generation of the microbubbles to vary. It is necessary to accurately control the bubble diameter distribution and the amount of bubbles generated in the microbubbles generated in the above, and the configuration F becomes important.

That is, the amount of bubbles generated is determined by the relationship between the flow rate of the liquid and the flow rate of the gas, but the gas dissolved in the liquid is generated as bubbles by the fluid supply route of the liquid and the gas from the gas-liquid supply means 19 to the laminated block 16. Then, the amount of bubbles generated in the venturi flow path 20 formed to generate microbubbles in the laminated block 16 varies depending on the degree of generation. This makes it difficult to control the amount of bubbles generated in the microbubbles, which causes variations in the bubble diameter distribution and the amount of bubbles generated.

On the other hand, by making the gas dissolved in the liquid generate as bubbles only in the Venturi flow path 20 formed in the laminated block 16, the relationship between the flow rate of the liquid and the flow rate of the gas can be clearly grasped. , It becomes easy to control the amount of bubbles generated in the microbubbles. Further, since the bubbles generated in other than the Venturi flow path 20 are not mixed, the variation in the bubble diameter distribution of the microbubbles can be reduced.

The liquid and gas fluid supply route from the gas-liquid supply means 19 to the laminated block 16 does not have a reduction / expansion portion in which the cross-sectional area of the flow path shifts from reduction to expansion, so that the flow path is other than the Venturi flow path 20. It is possible to prevent the generation of air bubbles as much as possible. If there is a minute enlarged portion in the fluid supply route, the cross-sectional area of the flow path is large and a structure similar to that of the Venturi flow path is formed, and bubbles having a large bubble diameter are likely to be generated.

Although not shown, if air bubbles are inevitably generated in the liquid and gas fluid supply route from the gas-liquid supply means 19 to the laminated block 16, a defoaming means is provided immediately before the laminated block 16. You can also do it.

[Proof experiment to solve the problem of laminated Venturi nozzle]
Next, with respect to the laminated venturi nozzle 10 of the first embodiment of the present invention configured as described above, a proof experiment as to whether or not the above-mentioned problem of the present invention can be solved will be described.

As shown in FIGS. 10A and 10B, the principle of generating microbubbles in the Venturi structure is that the gas mixed liquid introduced from the inlet 20E of the Venturi flow path 20 gradually shrinks in the cross-sectional area of the flow path. The pressure gradually decreases and the flow velocity increases as the flow path reducing portion 20A progresses. Then, in the throat portion 20C having the smallest cross-sectional area of the Venturi flow path 20, the flow velocity increases to the extent that it exceeds the speed of sound. After that, the pressure of the gas mixed liquid recovers and gradually increases as it advances through the flow path expanding portion 20B where the cross-sectional area of the flow path gradually increases.

As described above, when the cross-sectional area of the throat portion 20C is small, a choked flow is generated in the gas mixture to limit the flow rate, and the flow velocity increases to the extent that it exceeds the speed of sound, as shown in FIG. 10 (A). Immediately after leaving the throat portion 20C, the bubble K expands once, but after that, it causes a sudden contraction, division, and collapse of the bubble K, and microbubbles are generated.

That is, in the generation of microbubbles, how to design the flow path cross-sectional area of the throat portion 20C required to generate the choked flow is an important point including the bubble collapse phenomenon. Therefore, before the verification test, the appropriate dimensions in the cross section of the flow path of the throat portion 20C were investigated.

11A is a plan view of the laminated venturi nozzle 10 for testing, FIG. 11B is a front view, and FIG. 11C is an enlarged view of a circled portion of FIG. 11A.
As shown in FIG. 11, a four-layer structure laminated block having one Venturi flow path 20 having a square flow path cross-sectional shape as a nozzle having a Venturi structure for examining an appropriate dimension of the flow path cross section of the throat portion 20C. 16 was assembled as described above. Then, by connecting the supply block 18 to the assembled laminated block 16, the laminated venturi nozzle 10 for testing was obtained. The grooved block 12 for testing in FIG. 11 has one venturi flow path 20 and does not have two venturi flow paths 20, but the reference numerals are the same 12.

The grooved block 12 and the grooveless block 14 used in the laminated venturi nozzle 10 for the test were plate-shaped blocks having a width W of 50 mm and a length L of 90 mm and having flat surfaces on both sides. Further, the width D1 of the inlet 20E of the flow path reducing portion 20A in the Venturi flow path 20 is set to 10 mm, and the width D2 of the fluid ejection port 20D which is the outlet of the flow path expanding portion 20B is set to 7 mm. Further, the opening angle θ of the flow path expanding portion 20B was set to 6 °.

Further, the throat portion 20C has a square shape in which the horizontal width D3 and the vertical width D3 of the flow path cross section are the same, and a plurality of laminated venturi nozzles for testing in which the width D3 and the length T of the throat portion 20C are changed are manufactured. The appropriate dimensions of the throat portion 20C were investigated. In this case, the vertical width of the inlet 20E of the flow path reducing portion 20A and the vertical width of the fluid ejection port 20D of the flow path expanding portion 20B are the same as the width D3 of the throat portion.

As a result, it was found that the width (square) D3 of the throat portion 20C is preferably 1.0 mm or more and 5.0 mm or less. It is not only difficult in terms of cutting to make the width (square) D3 of the throat portion 20C less than 1.0 mm, but also foreign matter such as dust is likely to be clogged in the throat portion 20C. Further, when the width (square) D3 of the throat portion 20C exceeds 5.0 mm, there is a balance with the flow rate of the gas mixed liquid, but the choked flow in which the flow velocity exceeds the speed of sound is less likely to occur.

Further, the length T of the throat portion 20C is preferably 1.0 mm or more and 5.0 mm or less. The length T of the throat portion 20C should be as short as possible, but it is difficult to make it less than 1.0 mm in terms of cutting. Further, if it exceeds 5.0 mm, pressure recovery (pressure increase) in the flow path expanding portion 20B is less likely to occur, and bubbles are less likely to collapse.

In the above test for investigating the appropriate dimensions of the throat portion 20C, the cross-sectional shape of the flow path of the throat portion 20C was made square. However, even when the cross-sectional shape of the flow path is rectangular, it can be made rectangular as long as the vertical width and the horizontal width are 1.0 mm or more and 5.0 mm or less within the above preferable dimensional range.

(Proof test 1)
Next, the flow path cross-sectional area of the throat portion 20C (in the case of a plurality of venturi flow paths 20, the total flow path cross-sectional area) is made the same, and the number of venturi flow paths 20 is two laminated Venturi nozzles (sample 1). And, the bubble diameter distribution was investigated with the laminated Venturi nozzle (control 1) having one Venturi flow path.

As the laminated venturi nozzle of sample 1, the one shown in FIG. 8 was used, and the width D3 of the throat portion 20C was made into a square of 1.5 mm. That is, the cross-sectional area of the flow path in the throat portion 20C of the laminated Venturi nozzle of the sample 1 is 1.5 mm * 1.5 mm = 2.25 mm ² , and the total flow path breakage of the throat portions 20C in the two Venturi flow paths 20. The area will be 4.5 mm ² . Further, as the laminated venturi nozzle 10 of the control 1, as shown in FIG. 12, a single venturi flow path 20 having a flow path cross-sectional area of the throat portion 20C equal to that of the sample 1 was used. ..

That is, as shown in FIG. 12B, the laminated venturi nozzle 10 of the control 1 is laminated in the order of the grooveless block 14, the grooved block 12, the grooved block 12, and the grooveless block 14 from the left side (lower side). The laminated block 16 was formed by superimposing the surfaces of the two grooved blocks 12 on which the grooves were formed. The laminated venturi nozzle 10 of the control 1 has a rectangular shape with a width of 1.5 mm and a height of 3.0 mm of the throat portion 20C.

A gas mixture in which air was mixed with water was supplied to each of the laminated venturi nozzles 10 of the sample 1 and the control 1 described above at a flow rate of 10 L / min. Then, the bubble diameter distribution in Sample 1 and Control 1 was measured by passing the gas mixture ejected from the laminated Venturi nozzle 10 through the flow cell of SALD-2300, which is a laser diffraction type particle size distribution measuring device manufactured by Shimadzu Corporation. ..

The measurement results are shown in the graphs of FIGS. 13 and 14. FIG. 13 shows a control 1 (one Venturi flow path) having the same total flow path cross-sectional area of 4.5 mm ² of the throat portion 20C shown in (A) and a sample 1 (two Venturi flows) shown in (B). The bubble diameter distribution is measured when the gas-liquid volume flow rate ratio (β) is 0.02.

Further, FIG. 14 shows control 1 (one Venturi flow path) having the same total flow path cross-sectional area of the throat portion 20C shown in (A) and sample 1 (two Venturi flow paths) shown in (B). , The bubble diameter distribution was measured when the gas-liquid volume flow rate ratio (β) was 0.007. That is, FIG. 14 shows a case where the amount of gas in the gas mixture is smaller than that in FIG. Here, the gas-liquid volume flow rate ratio (β) is the ratio (%) of the volume flow rate of the gas to the total volume flow rate of the gas (for example, air) and the liquid (for example, water), and is the ratio of the gas contained in the liquid. Is shown.

In FIGS. 13 and 14, the horizontal axis indicates the particle size (μm) of the bubble. The vertical axis on the left side is the relative particle amount (integrated%) and is shown by the curve A, and the vertical axis on the right side is the relative particle amount (frequency%) and is shown by the bar graph B. Further, in the table of FIG. 15, based on the measurement results shown in the graphs of FIGS. 13 and 14, the bubble diameter is defined as the median diameter (particle diameter at which the cumulative frequency becomes 50%), the mode diameter (most frequent particle diameter), and the mode diameter. The average diameter (arithmetic average diameter) is shown in three types, and the bubble diameter distribution is shown in standard deviation.

(Result of verification test 1)
As a result, as can be seen from the table of FIG. 15, by passing 10 L / min of the gas mixed solution through the Venturi flow path 20 having a flow path cross-sectional area of 4.5 mm ² of the throat portion 20C, microbubbles having a bubble diameter in the vicinity of 30 μm are formed. Can be caused. Then, when the total flow path cross-sectional area of the throat portion 20C and the flow rate of the gas mixed liquid are the same, the two Venturi flow paths 20 are used regardless of whether the gas-liquid volume flow rate ratio (β) is 0.02 or 0.007. The laminated venturi nozzle of the sample 1 having the sample 1 is shifted to the side where the peak of the bubble diameter distribution is smaller than that of the laminated venturi nozzle of the control 1 having one venturi flow path 20. This can be seen by looking at the shift amount S1 between the center line X1 of the maximum peak of the bar graph in the control 1 of FIG. 13 (A) and the center line X2 of the maximum peak of the bar graph in the sample 1 of (B). Similarly, it can be seen by looking at the shift amount S2 between the center line X3 of the maximum peak of the bar graph in the control 1 of FIG. 14 (A) and the center line X4 of the maximum peak of the bar graph in the sample 1 of (B).

(Proof test 2)
Next, a laminated Venturi nozzle (Sample 2) having the same flow path cross-sectional area of the throat portion 20C and six Venturi flow paths 20 and a laminated Venturi nozzle (control) having one Venturi flow path 20. We investigated how the bubble diameter distribution would be in 2).

As the laminated venturi nozzle 10 of the sample 2, the one shown in FIG. 1 was used, and the width D3 of the throat portion 20C in each venturi flow path 20 was made into a square of 1.5 mm. That is, the cross-sectional area of the flow path in the throat portion 20C of the laminated Venturi nozzle of the sample 2 is 1.5 mm * 1.5 mm = 2.25 mm ² , and the total flow path breakage of the throat portions 20C in the six Venturi flow paths 20. The area will be 13.50 mm ² .

Further, although the laminated venturi nozzle 10 of the control 2 is not shown, one venturi flow path 20 has the same flow path cross-sectional area of the throat portion 20C as the sample 2, and other conditions are the same as the sample 2. I made it like this. As a result, the flow path cross-sectional area was not exactly the same as that of sample 2, but it was 12.57 mm ² , which was almost the same.

Then, for each of the sample 2 and the control 2, a gas mixture in which air was mixed with water was supplied to each of the laminated venturi nozzles 10 at a flow rate of 10 L / min, as in the verification test 1. Then, the bubble diameter distribution in the sample 2 and the control 2 was measured by passing the gas mixture ejected from the laminated Venturi nozzle 10 through the flow cell of SALD-2300, which is a laser diffraction type particle size distribution measuring device manufactured by Shimadzu Corporation. ..

The measurement results are shown in the graphs of FIGS. 16 and 17. FIG. 16 shows control 2 (one Venturi flow path) having substantially the same total flow path cross-sectional area of the throat portion 20C shown in (A) and sample 2 (six Venturi flow paths) shown in (B). , The bubble diameter distribution was measured when the gas-liquid volume flow rate ratio (β) was 0.013.

Further, FIG. 17 shows the control 2 (one Venturi flow path) having substantially the same total flow path cross-sectional area of the throat portion 20C shown in (A) and the sample 2 (six Venturi flow paths) shown in (B). The bubble diameter distribution was measured when the gas-liquid volume flow rate ratio (β) was 0.004. That is, FIG. 17 shows a case where the amount of gas in the gas mixture is smaller than that in FIG.

In FIGS. 16 and 17, as in the verification test 1, the horizontal axis indicates the particle size (μm) of the bubble. The vertical axis on the left side is the relative particle amount (integrated%) and is shown by the curve A, and the vertical axis on the right side is the relative particle amount (frequency%) and is shown by the bar graph B.

Further, in the table of FIG. 18, based on the measurement results shown in the graphs of FIGS. 16 and 17, the bubble diameter is defined as the median diameter (particle diameter at which the cumulative frequency becomes 50%), the mode diameter (most frequent particle diameter), and the mode diameter. The average diameter (arithmetic average diameter) is shown in three types, and the bubble diameter distribution is shown in standard deviation.

(Result of verification test 2)
As a result, as can be seen from the table of FIG. 18, when the gas mixed solution 10 L / min is passed through the Venturi flow path 20 having a flow path cross-sectional area of about 13 mm ² of the throat portion 20C, the bubble diameter is around 500 to 700 μm. It becomes larger than 1 to 100 μm defined as microbubbles. However, even in the verification test 2, when the total flow path cross-sectional area of the throat portion 20C and the flow rate of the gas mixed liquid are the same, the laminated Venturi nozzle 10 of the sample 2 having six Venturi flow paths 20 has one Venturi flow. The bubble diameter distribution is shifted to the side smaller than that of the laminated venturi nozzle 10 of the control 2 having a path. This can be seen by looking at the shift amount S3 between the center line Y1 of the maximum peak of the bar graph of the control 2 in FIG. 16 (A) and the center line Y2 of the maximum peak of the bar graph of the sample 2 in (B). Similarly, it can be seen by looking at the shift amount S4 between the center line Y3 of the maximum peak of the bar graph of control 2 in FIG. 17 (A) and the center line Y4 of the maximum peak of the bar graph of sample 2 in (B).

From the above verification test 1 and verification test 2, if the total flow path cross-sectional area of the throat portion 20C is the same, the venturi flow path 20 is mulched rather than one venturi flow path 20 (with a plurality of venturi flow paths 20). It can be seen that the bubble diameter can be made finer by constructing).

Further, when the standard deviations of the sample 1 and the control 1 in the table of FIG. 15 are compared, the sample 1 (two) in which the venturi flow path 20 is mulched is slightly smaller than that of the control 1 having one venturi flow path 20. Although it has become larger, it can be said that it is almost the same. On the other hand, when the standard deviations of the sample 2 and the control 2 in the table of FIG. 18 are compared, when the gas-liquid volume flow rate ratio (β) is 0.013, the venturi flow path 20 is Venturi as compared with the one control 2. The sample 2 (6 pieces) in which the flow paths 20 are mulched is slightly smaller. Further, when the gas-liquid volume flow rate ratio (β) is 0.004, the sample 2 (6 lines) in which the venturi flow path 20 is mulched is slightly smaller than the control 2 in which the venturi flow path 20 is one line. Although it has become larger, it can be said that it is almost the same. In particular, it should be noted that the standard deviation of the laminated Venturi nozzle 10 of the sample 2 mulched in the six Venturi flow paths 20 is smaller than that of the laminated Venturi nozzle 10 of the sample 1 mulched in the two Venturi flow paths 20. Deserves.

On the other hand, from the comparison of the bubble diameters between the verification test 1 and the verification test 2, when the flow rates of the gas mixed liquids are the same, the verification test 2 in which the flow path cross-sectional area of the throat portion 20C is large is the verification test in which the flow path cross-sectional area is small. It can be seen that the bubble diameter is larger than that of 1. It is considered that this is because when the cross-sectional area of the flow path of the throat portion 20C becomes large, the choked flow is less likely to occur and the bubble collapse is less likely to occur.

That is, the bubble diameter is related to the flow path cross-sectional area of the throat portion 20C and the flow rate of the gas mixed liquid. It turns out that it is necessary to make appropriate adjustments.

Therefore, the effect of the relationship between the cross-sectional area of the flow path of the throat portion 20C and the flow rate of the gas mixture on the bubble diameter was investigated by a homogeneous flow model (hereinafter referred to as a homogeneous flow model test). The homogeneous flow model regards a two-phase flow as a flow in which a gas phase and a liquid phase are uniformly mixed at the same velocity, and is particularly effective for a bubble flow or the like.

(Homogeneous flow model test)
FIG. 19 is a graph for investigating the influence of the relationship between the flow path cross-sectional area of the throat portion 20C and the flow rate of the gas mixed liquid on the bubble diameter using a homogeneous flow model. In FIG. 19, the horizontal axis is the gas-liquid volume flow rate ratio (β) and is represented by a logarithm (log). The vertical axis shows the flow rate (L / min) of the gas mixture.

The different flow path cross-sectional areas of the throat portion 20C are the case where the flow path cross-sectional area of the throat portion 20C is 2.25 mm ² (No. 1) and the case of 4.5 mm ² (No. 2) in one Venturi flow path 20. , And 9.0 mm ² for the three levels (No. 3).

Then, for each of No. 1 to No. 3, the flow rate of the gas mixed liquid was changed so that the inlet pressures of the inlet 20E of the venturi flow path 20 were 0.1 MPa, 0.2 MPa, and 0.3 MPa. In this case, if the inlet pressure of the venturi flow path 20 is the same even if the flow path cross-sectional area of the throat portion 20C is different, the flow velocity in the throat portion 20C can be regarded as the same, and it is presumed that the bubble diameters are the same. be able to. Further, the flow path cross-sectional area of the throat portion 20C and the gas mixture are defined with the range of 0.007 to 0.02, which is the range of the gas-liquid volume mixing ratio (β) of the verification test 1 in which microbubbles are generated, as a boundary line. The effect of the relationship with the flow rate on the bubble diameter was evaluated.

(Evaluation results)
Although the bubble diameter is not shown in FIG. 19, as described above, if the inlet pressure of the venturi flow path 20 is the same, the flow velocity at the throat portion 20C can be regarded as the same, and the bubble diameter is the same. I guessed that it would be, and evaluated it.

(A) From the comparison of No1 to No3, it can be seen that in order to obtain the same bubble diameter, the larger the flow path cross-sectional area of the throat portion 20C, the larger the flow rate of the gas mixed liquid is required.

(B) Comparing No. 1 to No. 3 for each of the inlet pressures of the Venturi flow path 20 of 0.1 MPa, 0.2 MPa, and 0.3 MPa, the smaller the flow path cross-sectional area of the throat portion 20C, the smaller the flow rate of the gas mixture. It can be seen that the bubble diameter can be obtained. For example, comparing No3: 0.3 MPa, No2: 0.3 MPa, and No1: 0.3 MPa, in order to obtain the same bubble diameter, No3: 0.3 MPa requires a flow rate of about 12 L / min, and No2: 0.3 MPa requires a flow rate of about 6 L / min, and No1: 0.3 MPa requires a flow rate of about 3 L / min.

(C) Comparing the inclination angles R1, R2, and R3 in the boundary line range of the curves of No. 1 to No. 3 when the inlet pressure of the venturi flow path 20 is 0.3 MPa, the larger the flow path cross-sectional area of the throat portion 20C, the larger the inclination angle. You can see that it gets bigger. This means that the larger the flow path cross-sectional area of the throat portion 20C, the greater the influence of the flow rate of the gas mixture on the bubble diameter and the greater the influence of the gas-liquid volume flow rate ratio (β) on the bubble diameter. do. That is, the larger the flow path cross-sectional area of the throat portion 20C, the narrower the range of the appropriate gas-liquid volume flow rate ratio (β) for obtaining microbubbles, and the variation in the bubble diameter distribution. It causes.

[Summary of verification test and homogeneous flow model test]
From the results of the verification test 1 and the verification test 2, it was proved that the bubble diameter can be reduced by mulching the Venturi flow paths. Further, it was proved that the bubble diameter distribution having the same standard deviation as that of one Venturi flow path 20 can be obtained by mulching the Venturi flow paths 20 so as to satisfy the above configurations A to E.

From the results of the homogeneous flow model test, if the flow path cross-sectional area of the throat portion 20C of the Venturi flow path 20 is the same, the bubble diameter also changes when the flow rate of the gas mixture (inlet pressure of the Venturi flow path 20) changes, and bubbles It can be seen that the diameter depends on the flow rate of the gas mixture. It can also be seen that when the gas-liquid volume flow rate ratio (β) is reduced, it is necessary to increase the flow rate of the gas mixture in order to obtain the same bubble diameter. In particular, when the flow path cross-sectional area of the throat portion 20C is large, it is easily affected by the gas-liquid volume flow rate ratio (β).

Therefore, in addition to mulching the venturi flow path 20, the flow rate and gas-liquid volume flow rate ratio of the gas mixed liquid supplied to the laminated Venturi nozzle 10 according to the total flow path cross section of the mulched throat portions 20C ( By appropriately adjusting β), a large amount of microbubbles having a small bubble diameter and a small variation in the bubble diameter distribution can be generated. In this case, by mulching the Venturi flow paths 20 and reducing the flow rate of the gas mixture to one Venturi flow path 20, the influence of the gas-liquid volume flow rate ratio (β) on the flow rate of the gas mixture is reduced. It is possible to stably obtain microbubbles having a small bubble diameter and a small variation in the bubble diameter distribution.

Therefore, as in the laminated Venturi nozzle 10 of the first embodiment of the present invention, by mulching the Venturi flow paths 20 so as to satisfy the above configurations A to E, the Venturi flow having a small flow path cross-sectional area is achieved. By forming a plurality of paths 20, a large amount of microbubbles (equivalent to one Venturi flow path 20) having a small bubble diameter and a small variation in the bubble diameter distribution in a Venturi structure that can be inexpensively installed. Can occur. Further, by satisfying the above configuration F, it becomes easy to control the amount of bubbles generated in the microbubbles, and bubbles generated in other than the Venturi flow path 20 are not mixed, so that the variation in the bubble diameter distribution of the microbubbles can be reduced.

Next, a microbubble liquid generation device using the laminated venturi nozzle 10 according to the first embodiment of the present invention configured as described above will be described.

[Micro bubble liquid generator]
FIG. 20 is an overall configuration diagram illustrating a microbubble liquid generation device that generates a microbubble liquid in which microbubbles are blown into a liquid. In the micro-bubble liquid generation device of the present embodiment, the case where water is used as the liquid and air is used as the gas will be described, but the present invention is not limited to water or air.

As shown in FIG. 20, the microbubble liquid generator 38 according to the embodiment of the present invention mainly has a container 40 for storing water and a circulation pipe 42 for extracting water from the container 40 and returning it to the container 40 (FIG. 6). (Corresponding to the pipe 36), a circulation pump 44 provided in the circulation pipe 42, a pressure melting device 46 provided on the upstream side of the circulation pump 44 of the circulation pipe 42 to pressurize and dissolve air in water, and a pressure dissolution device 46. It is composed of an air supply device 50 that supplies air to the device 46 via an air pipe 48, and a laminated venturi nozzle 10 of the present invention connected to a return position of the circulation pipe 42.

The container 40, the circulation pipe 42, the circulation pump 44, the pressure melting device 46, the air pipe 48, and the air supply device 50 mainly constitute the air-liquid supply means 19.
In FIG. 20, the circulation pipe 42 is shown by a solid line and the air pipe 48 is shown by a broken line.

The container 40 is formed of, for example, a cylindrical shape by a hard transparent resin such as acrylic resin, and the container 40 is covered with a lid 40A. The container 40 is placed on the rack 52 placed on the floor 51, and a plurality of openings 54, 54 through which the circulation pipe 42 and the air pipe 48 penetrate are formed on the upper surface of the rack 52. A discharge pipe 56 for discharging the water in the container 40 to the outside is connected to the bottom of the container 40, and an on-off valve 58 is provided in the discharge pipe 56.

In the circulation pipe 42, the draining side of the container 40 for draining water penetrates the end position of the bottom of the container 40 to open into the container 40, and the return side for returning water to the container 40 penetrates the center position of the bottom of the container 40 to enter the container. It is open in 40. The container 40 penetrating portion of the circulation pipe 42 is shielded by the shield members 60, 60 ... In the middle of the circulation pipe 42, a circulation pump 44 for sending water (or a gas mixture) flowing through the circulation pipe 42, a flow rate adjusting valve 62 for adjusting the flow rate of the gas mixture in which air is pressurized and dissolved in water, A flow meter 64 for measuring the flow rate of the gas mixture and a pressure gauge 66 for measuring the inlet pressure of the gas mixture supplied to the laminated venturi nozzle 10 are provided.

The pressure melting device 46 may be any device as long as it can efficiently dissolve air in water, and for example, a pressure melting tank can be used. The pressure-dissolving tank produces a gas mixture in which air is pressure-dissolved in water by showering water while supplying air into the pressure-resistant tank.

As the air supply device 50, for example, a compressor can be used. The air pipe 48 extending from the air supply device 50 is connected to the pressure melting device 46 via a flow rate adjusting valve 68 and an on-off valve 70 for adjusting the flow rate of the gas.

As the laminated venturi nozzle 10, the laminated venturi nozzle of the first embodiment of the present invention described above is used. The circulation pipe 42 corresponds to the pipe 36. Therefore, a male screw is engraved on the return side of the circulation pipe 42, and a female screw is formed in the supply flow path 18A of the supply block 18 of the laminated venturi nozzle 10. Therefore, by preparing a plurality of laminated Venturi nozzles 10 having different numbers of Venturi flow paths 20 and the total flow path cross-sectional area of the throat portions 20C, they can be easily replaced with the laminated Venturi nozzles 10 to be used.

Next, a method of generating the microbubble liquid using the microbubble liquid generation device 38 configured as described above will be described.
After storing water in the container 40, the number of venturi flow paths 20 of the laminated venturi nozzle 10 to be used and the total flow path cross-sectional area of the throat portion 20C are determined according to the amount of microbubble liquid to be generated, the microbubble concentration, and the like. ..

Next, the circulation pump 44 is operated and the air supply device 50 is operated. As a result, the pressure-dissolving device 46 prepares a gas mixture in which air is pressure-dissolved in water, and the prepared gas mixture flows through the circulation pipe 42 and is sent to the laminated Venturi nozzle 10. The gas mixed liquid sent to the laminated Venturi nozzle becomes a gas mixed liquid containing microbubbles and is blown into the water in the container 40 from the fluid ejection port 20D. In this case, the flow rate adjusting valve 68 is adjusted to mix with water so that the laminated venturi nozzle 10 efficiently generates microbubbles according to the total flow path cross-sectional area of the throat portion 20C of the laminated venturi nozzle 10. To adjust. Further, the flow rate adjusting valve 62 is adjusted while looking at the flow meter 64 and the pressure gauge 66 to adjust the flow rate of the gas mixed liquid sent to the laminated venturi nozzle 10. Specifically, the flow rate adjusting valve 68 and the flow rate adjusting valve 62 are adjusted with reference to the graph of FIG.

As a result, the water in the container 40 becomes cloudy due to the microbubbles blown from the laminated Venturi nozzle 10, and a microbubble liquid is generated.

In the microbubble liquid generation device 38 of the embodiment of the present invention, since the laminated venturi nozzle 10 of the first embodiment of the present invention is used as the device for generating microbubbles, the cost of the device can be reduced. It is possible to generate a microbubble liquid containing a large amount of microbubbles having a Venturi structure and a small bubble diameter and a small variation in the bubble diameter distribution. In addition, the bubble diameter distribution and the amount of bubbles generated in the microbubbles generated in the Venturi flow path 20 can be controlled with high accuracy.

In the laminated venturi nozzle 10 and the microbubble liquid generation device 38 of the first embodiment of the present invention described above, the gas / liquid supply means 19 for supplying the liquid and gas for generating microbubbles to the laminated block 16. The case of the supply block 18 having one supply flow path for supplying the gas mixed liquid in which the gas is mixed with the liquid by pressure dissolution in the laminated block 16 has been described.

However, only the liquid for generating microbubbles is supplied from the above-mentioned supply block 18 to the laminated block 16, and the gas supplies the gas supply channel 27 to the throat portion 20C of the venturi flow path 20 formed in the laminated block 16. The gas-liquid supply means 19 can also be configured to be separately supplied via the gas-liquid supply means 19.

Next, a modified example of the gas-liquid supply means 19 in which the liquid is supplied from the supply block 18 and the gas is directly supplied to the throat portion 20C of the venturi flow path 20 formed in the laminated block 16 will be described.

(Modified example of gas / liquid supply means)
In the modification of the air / liquid supply means 19, the laminated block 16 and the air / liquid supply means 19 are modified as follows. That is, the laminated block 16 is a gas supply hole 21 formed in the laminated direction (longitudinal direction) of the grooved block 12 and the grooveless block 14 laminated in the laminated block 16 in a predetermined total number, and the grooved block 12. A groove-shaped gas formed on the surface (the surface on which the groove of the venturi flow path 20 is formed), one end communicating with the throat portion 20C of the groove-shaped venturi flow path 20, and the other end communicating with the gas supply hole 21. It has a supply groove 23 and.

Further, the gas / liquid supply means 19 includes a liquid supply flow path 25 (corresponding to the circulation pipe 42 in FIG. 20 and the supply flow path 18A of the supply block 18) for supplying liquid to the fluid supply port 22A of the laminated block 16 and a laminated block. It has a gas supply flow path 27 (see FIG. 20) for supplying gas to the gas supply hole 21 bored in 16.

As shown in FIG. 20, by switching the gas supplied from the air supply device 50 with the switching valve 29, the gas can be supplied to the pressure melting device 46 or the throat portion 20C of the venturi flow path 20. Can be done.

Using FIGS. 21, 22, and 23, an example of a modification of the gas-liquid supply means 19 is a laminated structure composed of four layers of a grooved block 12 and a grooveless block 14 and six venturi flow paths 20 formed. The case of block 16 (in the case of FIG. 1) will be described.

That is, as shown in FIGS. 21A and 21B, one gas supply hole 21 is bored so as to penetrate the four layers of the laminated block 16 in the laminated direction (longitudinal direction). As shown in FIGS. 22 and 23, the gas supply hole 21 is formed at the same location of the grooved block 12 (3 sheets) and the grooveless block 14 (1 sheet). As shown in FIG. 21, the gas supply hole 21 is preferably formed at the position of the axis of symmetry N of the grooved block 12. Then, the gas supply flow path 27 (see FIG. 20) is connected to both of the gas supply holes 21.

In FIG. 21, the gas supply holes 21 penetrating the four layers of the laminated block 16 are provided so that gas can be supplied from both sides of the laminated block 16, but one end of the gas supply holes 21 is blocked. It may be drilled so that gas can be supplied from one side of the laminated block 16.
In particular, when the number of laminated blocks is four or more, it is desirable to enable gas to be supplied from both sides of the laminated block 16 because the flow rate and pressure of the gas can be equalized without being dispersed among the layers in the supply of gas. ..

Further, as shown in FIGS. 21 and 22, one end communicates with the throat portion 20C of the groove-shaped venturi flow path 20 and the other end communicates with the gas supply hole 21 on the surface of the three grooved blocks 12. A groove-shaped gas supply groove 23 is formed. Since the two venturi flow paths 20 are formed in the grooved block 12, two equidistant gas supply grooves 23 are formed on the left and right from the gas supply hole 21. The cross-sectional shape of the flow path of the gas supply groove 23 is preferably a square having a length and width of about 1 mm in accordance with the throat portion 20C having a square cross section.

Then, the liquid supply flow path 25 is communicated with the fluid supply port 22A of the laminated block 16, and the gas supply flow path 27 is communicated with the gas supply hole 21. As a result, the gas for generating microbubbles is directly supplied from the gas supply flow path 27 to the throat portion 20C of the venturi flow path 20 through the gas supply hole 21 and the gas supply groove 23, and the liquid supply flow path 25 is provided. It mixes with the liquid supplied to the Venturi flow path 20 via.
At this time, since the throat portion 20C is in a reduced pressure state by flowing a fluid such as water, air is naturally sucked from the gas supply hole 21 and the fluid in the throat portion is also mixed.

By forming the gas supply hole 21 penetrating the grooved block 12 and the grooveless block 14 in the stacking direction as described above, the gas is collectively supplied to the six Venturi flow paths 20 formed in the laminated block 16. Therefore, the gas can be evenly supplied to each Venturi flow path 20. In particular, by supplying gas from both sides of the laminated block 16 (upper surface and lower surface in the laminated direction of the laminated block 16), it is possible to supply the gas more evenly to the six Venturi flow paths 20 formed in the laminated block 16.

Further, one gas supply hole 21 is formed on the axis of symmetry N, and the gas supply groove 23 is equidistant to two parallel ventilated flow paths 20 formed symmetrically with the axis of symmetry N sandwiched from the gas supply hole 21. Formed by distance. As a result, gas can be supplied at an equal flow rate to all the Venturi flow paths 20 formed in the laminated block 16.

Further, in the length T of the throat portion 20C (see (C) in FIG. 11), the penetrating position (connection position) of the gas supply hole 21 to the throat portion 20C becomes the pressure after the fluid pressure becomes the lowest. It is preferably near the fluid outlet in the throat portion 16C to be recovered. In this way, since the negative pressure is generated by connecting the gas supply hole 21 to the position of the throat portion 20C where the pressure is the lowest, the gas can be automatically sucked into the venturi flow path 20 by the ejector effect. .. Therefore, the gas can be more evenly supplied to the plurality of Venturi flow paths 20 formed in the laminated block 16.

In FIGS. 21 and 22, the gas supply groove 23 is made orthogonal to the axis of symmetry N of the grooved block 12. That is, the gas is supplied from the direction orthogonal to the flow direction of the liquid flowing through the throat portion 20C of the Venturi flow path 20. However, as shown in FIG. 24, it is more preferable that the gas is supplied to the throat portion 20C from diagonally rearward. That is, as shown in FIG. 24, the gas supply hole 21 formed on the axis of symmetry N is formed at the upstream position of the throat portion 20C when viewed from the flow direction of the liquid flowing through the venturi flow path 20, and the liquid flow. The gas supply groove 23 is formed at an acute angle with respect to the direction. As a result, the flow direction of the liquid and the supply direction of the gas become substantially the moving directions, so that the gas is more easily sucked into the throat portion 20C, and the gas can be more evenly supplied to all the Venturi flow paths 20. ..

Further, since the structure is such that the laminated Venturi nozzle 10 of the present invention is formed by laminating the grooved block 12 and the grooveless block 14 to form the laminated block 16, the venturi flow path 20 is increased. For directly supplying gas to the throat portion 20C of the venturi flow path 20 with an extremely simple structure in which a gas supply hole 21 is formed in the stacking direction of the laminated block 16 and a gas supply groove 23 is formed in the grooved block 12. A flow path can be formed. Further, since a flow path for directly supplying gas to the throat portion 20C of the venturi flow path 20 is automatically formed according to the number of grooved blocks 12 used for the laminated block 16, the number of venturi flow paths 20 is increased. It is not necessary to increase or decrease the number of flow paths for directly supplying to the throat portion 20C.

[Second Embodiment of Laminated Venturi Nozzle]
In the first embodiment of the laminated Venturi nozzle 10 described above, the amount of microbubbles generated can be increased by forming the Venturi flow path 20 not only in the vertical direction (stacking direction) of the three-dimensional structure but also in the horizontal direction. In addition, two parallel Venturi flow paths 20 were formed in the grooved block 12.

However, the basic feature of the laminated Venturi nozzle 10 of the present invention is to form a laminated Venturi nozzle in which the amount of microbubbles generated can be freely changed by an extremely simple method of laminating a grooved block 12 and a grooveless block 14. A second embodiment of the laminated Venturi nozzle described below can be configured.

In the laminated venturi nozzle 10 of the second embodiment of the present invention, as shown in FIGS. 25A and 25, a flow in which the cross-sectional area of the flow path gradually decreases on the surface of the block whose both sides are flat. A groove in which at least one groove-shaped venturi flow path 20 having a throat portion 20C having the smallest flow path cross-sectional area is formed between the path reduction portion 20A and the flow path expansion portion 20B in which the flow path cross-sectional area gradually expands. Formed on the laminated block 16 and the connecting means 17 for connecting the present block 12, the plate-shaped non-grooved block 14 having flat surfaces on both sides, and the laminated block 16 in which the grooved block 12 and the non-grooved block 14 are laminated. The laminated block 16 has a gas-liquid supply means 19 (see FIG. 20) that supplies a liquid for generating microbubbles and a gas to be mixed with the liquid in the venturi flow path 20, and the laminated block 16 has a groove-shaped venturi flow path. A three-dimensional structure in which two or more venturi flow paths 20 are formed by stacking three or more layers of a grooved block 12 and a grooveless block 14 according to the amount of microbubbles generated so that 20 becomes a tubular flow path. In addition, the fluid outlet 20D and the fluid supply port 22A of the tubular flow path are formed, and the liquid and gas fluid supply routes from the gas-liquid supply means 19 to the laminated block 16 do not generate bubbles.

The specific configuration in which bubbles are not generated in the liquid and gas fluid supply route from the gas-liquid supply means 19 to the laminated block 16 is the same as that of the laminated venturi nozzle 10 of the first embodiment, and the flow path cross-sectional area is the same. Does not have a reduction / enlargement part that shifts from reduction to enlargement.

Note that FIG. 25 shows the case of the laminated block 16 in which the two venturi flow paths 20 are formed in a three-dimensional structure in which the two grooved blocks 12 and the two grooveless blocks 14 are laminated in four layers. Any three-dimensional structure may be used in which two or more Venturi flow paths 20 are formed by stacking three or more layers according to the amount of microbubbles generated.

The laminated venturi nozzle 10 of the second embodiment of the present invention configured as described above satisfies the configurations of the above configurations A to F excluding configuration B and configuration D described in the first embodiment. It is formed so as to have the same effect as that of the first embodiment.

Further, also in the case of the laminated venturi nozzle 10 of the second embodiment, as described in the modified example (FIGS. 21 to 24) of the gas-liquid supply means 19 in the laminated venturi nozzle 10 of the first embodiment. The supply block 18 may be configured to supply only the liquid for generating microbubbles to the laminated block 16 and separately supply the gas to the throat portion 20C of the venturi flow path 20 formed in the laminated block 16. can.

In the laminated venturi nozzle 10 of the second embodiment, the reason why the laminated block is set to three or more layers and the two-layer laminate is removed is that in the case of the second embodiment, the laminated block is formed in the grooved block 12. This is because the case where the number of Venturi flow paths 20 is one is included, and it is difficult to obtain the above-mentioned flexible effect of the number of Venturi flow paths.

10 ... Laminated Venturi Nozzle, 12 ... Grooved Block, 12A ... Front Side, 12B ... Rear Side, 14 ... No Groove Block, 16 ... Laminated Block, 17 ... Connecting Means, 17A ... Bolt, 17B ... Nut, 18 ... Supply Block, 18A ... Supply flow path, 18B ... Female screw, 19 ... Gas / liquid supply means, 20 ... Venturi flow path, 20A ... Flow path reduction section, 20B ... Flow path expansion section, 20C ... Throat section, 20D ... Fluid spout , 20E ... inlet, 21 ... gas supply hole, 22 ... 2 branch flow path, 22A ... fluid supply port, 23 ... gas supply groove, 24 ... bolt hole, 25 ... liquid supply flow path, 26 ... screw hole, 27 ... gas Supply flow path, 28 ... fitting notch, 29 ... switching valve, 30 ... overhanging part, 30A ... upper overhanging part, 30B ... lower overhanging part, 32 ... screw, 34 ... through hole, 36 ... piping, 36A ... male Screw, 38 ... micro bubble fluid generator, 40 ... container, 42 ... circulation pipe, 44 ... circulation pump, 46 ... pressure melting device, 48 ... air pipe, 50 ... air supply device, 51 ... floor, 52 ... rack, 54 ... Opening, 56 ... Discharge pipe, 58 ... Open / close valve, 60 ... Shield member, 62 ... Flow adjustment valve, 64 ... Flow meter, 66 ... Pressure gauge, 68 ... Flow adjustment valve, 70 ... Open / close valve, N ... Axis of symmetry , M ... Axial core, K ... Bubble, F ... Distance, D1 ... Venturi flow path inlet width, D2 ... Venturi flow path fluid outlet width, D3 ... Throat part width, T ... Throat part length, L ... block length, W ... block width, S1 to S4 ... shift amount, P ... supply block width, A ... curve, B ... graph

Claims (16)

In a Venturi-structured nozzle for generating microbubbles,
On the surface of the block whose both sides are flat, there is a throat portion with the smallest flow path cross-sectional area between the flow path reduction part where the flow path cross-sectional area gradually shrinks and the flow path expansion part where the flow path cross-sectional area gradually expands. A groove formed so that two parallel groove-shaped Venturi flow paths and a Y-groove-shaped two-branch flow path communicating with the inlet of the flow path reduction portion of the two Venturi flow paths are symmetrical. With a block,
A plate-shaped non-grooved block with flat sides and
A connecting means for connecting a laminated block in which a predetermined total number of the grooved block and the grooveless block are laminated,
The laminated block has a gas-liquid supply means for supplying a liquid for generating the microbubbles and a gas to be mixed with the liquid.
The laminated block has a plurality of grooves by laminating the grooved block and the grooveless block so that the groove-shaped venturi flow path and the Y-groove-shaped bifurcated flow path become a tubular flow path. A tubular flow path is formed, and a fluid outlet and a fluid supply port of the tubular flow path are formed.
A laminated Venturi nozzle, characterized in that the fluid supply route of the liquid and the gas from the gas-liquid supply means to the laminated block does not have a shrinking / expanding portion in which the cross-sectional area of the flow path shifts from shrinking to expanding. The laminated venturi nozzle according to claim 1, wherein the fluid supply route does not generate bubbles because it does not have the reduced / enlarged portion. The gas-liquid supply means according to claim 1 or 2, wherein the gas-liquid supply means is a supply block having one supply flow path for supplying a gas mixture in which the gas is mixed with the liquid by pressure dissolution in the laminated block. Laminated Venturi Nozzle. The laminated block is
A gas supply hole formed in the stacking direction of the laminated block and communicating the grooved block and the grooveless block,
It has a groove-shaped gas supply groove formed on the surface of the grooved block, one end communicating with the throat portion of the groove-shaped Venturi flow path and the other end communicating with the gas supply hole. ,
The air-liquid supply means is
A liquid supply flow path for supplying the liquid to the fluid supply port of the laminated block,
It has a gas supply flow path for supplying the gas to the gas supply hole bored in the laminated block.
The laminated venturi nozzle according to claim 1 or 2, wherein the liquid is supplied to the fluid supply port of the laminated block, and the gas is separately supplied to the throat portion of the venturi flow path formed in the laminated block. The laminated Venturi nozzle according to any one of claims 1 to 4, wherein the Venturi flow path and the bifurcated flow path formed in the laminated block have a square or rectangular cross-sectional shape. The third aspect of claim 3, wherein the four or more Venturi flow paths formed in the laminated block are formed so as to be substantially located on the circumference of the supply block about the axis of the supply flow path. Laminated Venturi nozzle. The laminated venturi nozzle according to any one of claims 1 to 6, wherein the number of each of the grooved block and the grooveless block of the laminated block is set by the number of formed venturi flow paths. The laminate according to claim 3, wherein a fitting notch for fitting and connecting the supply block to the laminated block is formed on the block side of the laminated block on the side where the fluid supply port is formed. Venturi nozzle. In the laminating of the grooved block and the grooveless block constituting the laminated block, the front surface and the back surface of the grooved blocks or the front surface of the grooved block and the grooveless block are overlapped with each other, and the groove is formed. The laminated venturi nozzle according to any one of claims 1 to 8, wherein the flow path cross-sectional area of the venturi flow path can be changed depending on the case where the surfaces of the existing blocks are overlapped with each other. The one according to any one of claims 1 to 9, wherein the laminated block has a three-dimensional structure in which four or more Venturi flow paths are formed by laminating three or more layers according to the amount of microbubbles generated. Laminated Venturi Nozzle. Any one of claims 4 to 10 in which the rectangular vertical width and horizontal width of the throat portion in the Venturi flow path are 1.0 mm or more and 5.0 mm or less and the length is 1.0 mm or more and 5.0 mm or less. The laminated Venturi nozzle described in the section. In the method of manufacturing a Venturi-structured nozzle for generating microbubbles,
On the surface of the block whose both sides are flat, two groove-shaped Venturi flow paths having a flow path expansion portion in which the flow path cross-sectional area gradually expands following the flow path reduction portion in which the flow path cross-sectional area gradually shrinks, and the above-mentioned A grooved block forming step of forming a grooved block formed so that the Y-groove-shaped bifurcated flow paths communicating with the inlets of the flow path reduction portions of the two Venturi flow paths are symmetrical.
A grooveless block forming process for forming a plate-shaped grooveless block with flat surfaces on both sides,
A plurality of tubular flow paths are formed by laminating the grooved block and the grooveless block so that the groove-shaped Venturi flow path and the Y-groove-shaped bifurcated flow path become a tubular flow path. In addition, a step of forming a laminated block that forms a fluid outlet and a fluid supply port of the tubular flow path, and
A connecting step of connecting the grooved block and the grooveless block of the laminated block,
A single supply flow path that supplies a gas mixture in which a gas is pressurized and dissolved to a plurality of the fluid supply ports formed in the laminated block and does not have a reduction / expansion portion in which the cross-sectional area of the flow path shifts from reduction to expansion. A method for manufacturing a laminated Venturi nozzle, which comprises a supply block connecting process for connecting a supply block having a. The method for manufacturing a laminated Venturi nozzle according to claim 12, wherein in the grooved block forming step, the groove-shaped venturi flow path and the Y-groove-shaped bifurcated flow path are formed by cutting. In a microbubble liquid generator that generates microbubble liquid by blowing microbubbles into a liquid,
The container for storing the liquid and
A circulation pipe that draws out the liquid from the container and returns it to the container again.
The circulation pump provided in the circulation pipe and
A pressure-dissolving device provided on the upstream side of the circulation pump of the circulation pipe to pressurize and dissolve a gas in the liquid flowing through the circulation pipe.
An air supply device that supplies the gas to the pressure melting device via a gas supply pipe,
The microbubble liquid generation device comprising the laminated venturi nozzle according to any one of claims 1 to 11 connected to the return position of the circulation pipe. In a Venturi-structured nozzle for generating microbubbles,
On the surface of the block whose both sides are flat, there is a throat portion with the smallest flow path cross-sectional area between the flow path reduction part where the flow path cross-sectional area gradually shrinks and the flow path expansion part where the flow path cross-sectional area gradually expands. A grooved block with at least one grooved Venturi flow path,
A plate-shaped non-grooved block with flat sides and
A connecting means for connecting the laminated block in which the grooved block and the grooveless block are laminated, and
The Venturi flow path formed in the laminated block has a gas-liquid supply means for supplying a liquid for generating the microbubbles and a gas mixed with the liquid.
Two of the laminated blocks are formed by laminating three or more layers of the grooved block and the grooveless block according to the amount of microbubbles generated so that the grooved Venturi flow path becomes a tubular flow path. In addition to the three-dimensional structure in which the above Venturi flow path is formed, the fluid outlet and the fluid supply port of the tubular flow path are formed.
A laminated Venturi nozzle, characterized in that the fluid supply route of the liquid and the gas from the gas-liquid supply means to the laminated block does not have a shrinking / expanding portion in which the cross-sectional area of the flow path shifts from shrinking to expanding. The laminated venturi nozzle according to claim 15, wherein bubbles are not generated in the fluid supply route because the fluid supply route does not have the reduced / enlarged portion.

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