Fine bubble generating device and method for manufacturing fine bubble generating device

Abstract

A microbubble generating device includes a bubble generator that mixes liquid continuously supplied from a liquid supply source with gas supplied from a gas supply mechanism to generate microbubbles, and discharges a gas-liquid mixture containing the microbubbles. The bubble generator comprises: a manifold having a liquid inlet for supplying liquid, a gas inlet for supplying gas, and an outlet for generating microbubbles and discharging the gas-liquid mixture containing the microbubbles, and formed as a separate component; and a tubular internal component assembled and housed inside the manifold, having a flow path inside for allowing liquid supplied from the liquid inlet to flow to the outlet. The internal component consists of a downstream inner tube and an upstream inner tube, the downstream inner tube being disposed downstream in the direction of liquid flow and formed as a separate component, and the upstream inner tube being disposed upstream and formed as a separate component. The upstream inner tube has a through hole that allows gas supplied from the gas inlet to be introduced into the flow path. The downstream inner tube is connected to the upstream inner tube inside the manifold. The flow path connects the upstream inner tube and the downstream inner tube in a roughly coaxial manner from the liquid inlet to the outlet.

Description

Technical Field

[0001] This invention relates to a microbubble generating apparatus for generating microbubbles in a liquid and a method for manufacturing the microbubble generating apparatus. Background Technology

[0002] Microbubbles with a diameter of less than 50 μm are called "microbubbles" or "nanobubbles," and they possess properties different from larger bubbles (with a diameter of 1 mm or more) found in ordinary carbonated water. These microbubbles exhibit characteristics such as: increased dissolved oxygen and other dissolved gas concentrations due to their high solubility in liquids; negatively charged surface; high solubility of gases like air and oxygen; and various physiologically active effects. Therefore, this microbubble technology is used in various fields.

[0003] For example, in agriculture, in soil cultivation and hydroponics, oxygen can be appropriately supplied to roots prone to oxygen deficiency by dispersing water containing microbubbled air into the culture medium. By creating microbubbles, the amount of dissolved gas increases, and the smaller the bubble diameter, the less likely the bubble is to break and the more stably it remains in the water. As a result, water with a high concentration of dissolved oxygen can be provided to plants, thus accelerating growth and yielding high-quality crops. Furthermore, reports indicate that increasing the dissolved oxygen concentration in water can inhibit anaerobic bacteria and repel pests.

[0004] Furthermore, in the beauty and health fields, it is known that when water containing microbubbled air is used to cleanse hair, scalp, and other skin, the microbubbles selectively adsorb oil and dirt attached to the hair, resulting in excellent cleaning. It is said that the smaller the diameter of the microbubbles, the more they can penetrate into the gaps between hair roots and hair tissue, thus improving the cleaning effect. Additionally, it has been confirmed that the stimulation of sensory nerves by microbubbles increases blood flow and promotes blood circulation.

[0005] As a device for generating such microbubbles, Patent Document 1 discloses a device for generating microbubbles inside a tubular body. The microbubble generating device described in Patent Document 1 is an epoch-making device that can achieve a high concentration of microbubbles in a liquid and generate microbubbles with a diameter of less than tens of micrometers.

[0006] Existing technical documents Patent documents Patent Document 1: International Publication No. 2019 / 212028 Summary of the Invention

[0007] The problem that the invention aims to solve The existing microbubble generator described in Patent Document 1 (see reference) Figure 19 Microbubbles are generated by mixing liquid L continuously supplied from a liquid supply source with gas G supplied from a gas supply mechanism, and the gas-liquid mixture M containing the microbubbles and liquid is discharged. In order to introduce pressurized gas G into the continuously supplied liquid L, high gas pressure must be met around the through-hole 56 through which gas G flows in the tubular body 130, which becomes the liquid flow path 70, and high water pressure must also be met inside the tubular body 130.

[0008] To meet this requirement, in Patent Document 1, the tubular body 130 is integrally formed with the axis of the flow path 70 in a straight line, and the periphery of the through hole 56 is locked by the nut 120, thereby tightly connecting and fixing it to the sleeve 110. However, such a structure has many parts and the manufacturing process is cumbersome.

[0009] This invention is based on the viewpoint that its purpose is to provide a microbubble generator that improves product strength and has low manufacturing cost, as well as a method for manufacturing the microbubble generator.

[0010] Methods for solving problems The inventors' repeated and in-depth research has shown that manufacturing costs can be reduced by combining the individually formed tubular bodies. In Patent Document 1, pressure resistance is ensured by forming the tubular bodies integrally, but according to the configuration of the tubular bodies (internal components) and sleeves (manifolds) of the present invention, it has been found that sufficient pressure resistance can be ensured even when the tubular bodies are divided.

[0011] According to the present invention, a microbubble generating device is provided, comprising a bubble generator that mixes liquid continuously supplied from a liquid supply source with gas supplied from a gas supply mechanism to generate microbubbles, and discharges a gas-liquid mixture containing microbubbles. The bubble generator comprises a manifold and a tubular internal component. The manifold has a liquid inlet for supplying liquid, a gas inlet for supplying gas, and an outlet for generating microbubbles and discharging the gas-liquid mixture containing microbubbles, and is formed as a separate component. The tubular internal component is assembled and housed inside the manifold, and has a flow path inside for allowing liquid supplied from the liquid inlet to flow to the outlet. The internal component consists of a downstream inner tube and an upstream inner tube. The downstream inner tube is disposed downstream in the direction of liquid flow and is formed as a separate component. The upstream inner tube is disposed upstream and is formed as a separate component. The upstream inner tube has a through hole for introducing gas supplied from the gas inlet into the flow path. The downstream inner tube is connected to the upstream inner tube inside the manifold, and the flow path connects the upstream inner tube and the downstream inner tube in a roughly coaxial manner from the liquid inlet to the outlet.

[0012] According to the present invention, a liquid-gas mixture flowing in the flow path inside a bubble generator can be efficiently discharged, containing microbubbles with nanoscale bubble diameters. The bubble generator is configured such that a manifold, formed as a separate component, serves as a sleeve, and internal components are disposed within it. The internal components are assembled by accommodating an upstream inner tube and a downstream inner tube, both formed as separate components, within the manifold. While the assembly process of inserting long tubular members into other tubular members is cumbersome, assembly is easy because the internal components are segmented. Furthermore, pressure resistance is ensured by connecting the upstream and downstream inner tubes within the manifold. Moreover, since the bubble generator is constructed by accommodating internal components within the manifold, product strength is increased, and connection to piping is easy. Therefore, the microbubble generator not only has low manufacturing costs but also reduces maintenance costs.

[0013] Preferably, the downstream inner tube has a downstream connecting portion connected to the upstream inner tube, a downstream end connected to the interior of the outlet portion, and a downstream diameter reduction portion that reduces the inner diameter from the downstream connecting portion toward the downstream end. The upstream inner tube has an upstream diameter reduction portion that reduces the inner diameter toward the downstream side, an expansion portion that expands the inner diameter from the upstream diameter reduction portion toward the downstream side, and an upstream connecting portion connected to the downstream connecting portion. A through hole is disposed in the expansion portion.

[0014] With this configuration, inside the bubble generator, the flow path for the liquid continuously supplied from the liquid supply source is formed such that the diameter of the inner tube first narrows and then widens on the upstream side, then narrows again on the downstream side and widens at the outlet. In the section with a small diameter of the flow path, a depressurization state occurs due to the Venturi effect, resulting in a larger pressure difference with the gas pressurized to above atmospheric pressure. A large amount of gas is drawn into the flow path from the through-hole. In this invention, the flow velocity of the gas introduced into the flow path is increased, and the gas forcefully introduced into the flow path from the through-hole generates a strong swirling flow between the widening section and the downstream narrowing section (gas-liquid mixing section). Therefore, a large amount of gas can be introduced into the flow path, and the gas and liquid are thoroughly mixed inside the flow path to obtain a gas-liquid mixture with a large number of bubbles. Furthermore, because the flow velocity of the gas introduced into the flow path from the through-hole is high, the flow velocity of the liquid (gas-liquid mixture) flowing within the flow path is accelerated. Furthermore, in this invention, the gas-liquid mixture that has passed through the upstream section with a small inner diameter and the gas-liquid mixing section then passes through the downstream section with a small inner diameter. At this time, in the downstream section with a small inner diameter, the pressure is reduced due to the Venturi effect, causing the bubbles in the gas-liquid mixture to expand. However, because the outlet section has a large inner diameter, the flow rate decreases and the pressure increases. Therefore, in the outlet section, the expanded bubbles are crushed and contracted, resulting in microbubbles with even smaller diameters.

[0015] Preferably, the minimum inner diameter of the downstream inner tube is smaller than the minimum inner diameter of the upstream inner tube, and the outlet portion has a portion at least larger than the minimum inner diameter of the downstream inner tube. This allows for smaller bubble diameters, resulting in a gas-liquid mixture with microbubbles having nanometer-scale bubble diameters. It should be noted that, in this specification, nanometer-scale bubble diameters refer to microbubbles with a diameter less than 1 μm.

[0016] Preferably, the downstream end is fitted and connected to the outlet section. This configuration creates a strong connection between the outlet section and the downstream inner tube, improving the pressure resistance of the bubble generator. Furthermore, the fitting allows for the positioning of internal components, facilitating component assembly.

[0017] Preferably, the central axis of the flow path in the downstream narrowing section is coaxial with the central axis of the flow path in the upstream narrowing section. This ensures that the flow velocity of the gas-liquid mixture flowing within the flow path remains high, and therefore, the gas-liquid mixture discharged through the outlet section can also have suitable hydraulic pressure.

[0018] Preferably, the downstream connection is connected to the upstream connection in such a way that its inner surface is substantially the same as the inner surface of the upstream connection. Although the liquid flowing in the flow path in the downstream and upstream connections generates high pressure, the pressure resistance of the microbubble generator is improved by making these inner surfaces the same.

[0019] Preferably, the downstream connection and the upstream connection are connected at their end faces, which are substantially perpendicular to the central axis of the flow path in the upstream narrowing section. With this configuration, the assembly of internal components becomes easier, and the pressure resistance is also improved.

[0020] Preferably, the through-hole is inclined relative to the central axis of the flow path in the upstream constriction section and penetrates the pipe wall of the expansion section. With this configuration, gas is more violently introduced into the gas-liquid mixing section from the through-hole, generating a strong swirling flow within the gas-liquid mixing section, thus obtaining a gas-liquid mixture with a large number of bubbles. Therefore, the gas-liquid mixture discharged according to the present invention can contain microbubbles at a higher concentration.

[0021] Preferably, there are multiple through holes, evenly distributed circumferentially in the expanded diameter section. This allows the pressurized gas to be more violently introduced into the gas-liquid mixing section, generating a strong swirling flow. Consequently, the pressurized gas and liquid are thoroughly mixed in the flow path, resulting in a gas-liquid mixture with a large number of bubbles.

[0022] Preferably, a gap is formed between the outer surface of the narrowed and widened sections on the upstream side and the inner surface of the manifold, with each through hole extending from the gap to the flow path. This configuration allows for more efficient introduction of pressurized gas into the gas-liquid mixing section.

[0023] Preferably, the liquid inlet, gas inlet, and outlet are each formed with threads for connection to other piping. This configuration allows for efficient and more secure piping connection to the bubble generator, and also improves the pressure resistance of the bubble generator.

[0024] Furthermore, according to the present invention, a method for manufacturing a microbubble generating device is provided, wherein the microbubble generating device mixes a liquid continuously supplied from a liquid supply source with a gas supplied from a gas supply mechanism to generate microbubbles, and discharges a gas-liquid mixture formed by the microbubbles and the liquid. The manufacturing method includes: a step of forming a manifold as an independent component, the manifold having a liquid inlet for supplying liquid to the interior, a gas inlet for supplying gas to the interior, and an outlet for generating microbubbles and discharging a gas-liquid mixture containing microbubbles; a step of forming a downstream inner tube as an independent component, the downstream inner tube being disposed downstream in the direction of liquid flow; a step of forming an upstream inner tube as an independent component, the upstream inner tube being disposed upstream in the direction of liquid flow and having a through hole for introducing gas supplied from the gas inlet; and a step of assembling and accommodating the downstream inner tube and the upstream inner tube communicating with the downstream inner tube inside the formed manifold in such a way that the formed upstream inner tube and the formed downstream inner tube are coaxially arranged to form a flow path for allowing liquid supplied from the liquid inlet to flow to the outlet.

[0025] According to the present invention, a gas-liquid mixture containing microbubbles with nanometer-scale bubble diameters can be effectively discharged from a liquid-gas mixture flowing in a flow path inside a bubble generator. The bubble generator is configured with a manifold formed as a separate component as a sleeve, and internal components are arranged inside it. The internal components are assembled by connecting an upstream inner tube and a downstream inner tube, both formed as separate components, inside the manifold. Assembly operations such as inserting long tubular members into the interior of other tubular members are very cumbersome, but by dividing the internal components, assembly is made easier. Furthermore, by connecting the upstream and downstream inner tubes inside the manifold, pressure resistance is also ensured. Furthermore, since the bubble generator is constructed by accommodating internal components inside the manifold, product strength is improved, and connection to piping is easy. Therefore, the microbubble generating device not only has low manufacturing costs but also reduces maintenance costs.

[0026] Preferably, the downstream inner tube forming process includes a process of forming a downstream inner tube having a downstream connecting portion connected to the upstream inner tube, a downstream end connected to the interior of the outlet portion, and a downstream diameter reduction portion that reduces the inner diameter from the downstream connecting portion toward the downstream end. The upstream inner tube forming process includes a process of forming an upstream inner tube and distributing a through hole in the diameter expansion portion. The upstream inner tube has an upstream diameter reduction portion that reduces the inner diameter toward the downstream side, a diameter expansion portion that expands the inner diameter from the upstream diameter reduction portion toward the downstream side, and an upstream connecting portion connected to the downstream connecting portion.

[0027] Preferably, the downstream inner tube forming process or the upstream inner tube forming process includes a process of forming such that the minimum inner diameter of the downstream inner tube is smaller than the minimum inner diameter of the upstream inner tube, and the manifold forming process includes a process of forming such that the outlet portion has a portion that is at least larger than the minimum inner diameter of the downstream inner tube.

[0028] Preferably, the assembly process includes a process in which the downstream end of the downstream inner tube is fitted and connected to the outlet portion of the aforementioned manifold.

[0029] Preferably, the assembly process includes a process in which the central axis of the flow path in the downstream diameter reduction section of the downstream inner tube and the central axis of the flow path in the upstream diameter reduction section of the upstream inner tube are arranged coaxially.

[0030] Preferably, the assembly process includes connecting the inner surface of the downstream connecting portion of the downstream inner tube to the upstream connecting portion in a manner where the inner surface of the upstream connecting portion of the upstream inner tube is approximately the same as the inner surface of the upstream connecting portion of the upstream inner tube.

[0031] Preferably, the assembly process includes connecting the downstream connecting portion of the downstream inner tube and the upstream connecting portion of the upstream inner tube to each other through an end face that is substantially perpendicular to the central axis of the flow path in the upstream diameter reduction portion of the upstream inner tube.

[0032] Preferably, the upstream inner tube forming process includes forming the upstream inner tube by means of a through hole that is inclined relative to the central axis of the flow path in the upstream reduced diameter section and penetrates the tube wall of the expanded diameter section.

[0033] Preferably, the upstream inner tube forming process includes the process of forming a plurality of through holes evenly arranged circumferentially on the enlarged diameter portion.

[0034] Preferably, the assembly process includes assembling the tube in such a way that a gap is formed between the outer surface of the upstream-side reduced-diameter section and the expanded-diameter section of the upstream inner tube and the inner surface of the manifold, so that multiple through holes extend from the gap to the flow path.

[0035] Preferably, the manifold forming process includes forming threads for connection with other piping in the liquid inlet, gas inlet, and outlet sections.

[0036] Invention Effects According to the present invention, a microbubble generating apparatus and a method for manufacturing the microbubble generating apparatus can be provided, exhibiting the following excellent effects. Specifically, in the microbubble generating apparatus, the bubble generator is assembled such that an upstream inner tube and a downstream inner tube, each formed as an independent component, are housed within a manifold, and the upstream and downstream inner tubes are connected within the manifold, thereby facilitating assembly and providing excellent pressure resistance. Furthermore, a gas-liquid mixture containing microbubbles with nanometer-sized diameters can be efficiently discharged. Attached Figure Description

[0037] [ Figure 1 ] Figure 1 This is a diagram illustrating the configuration of a microbubble generating apparatus according to one embodiment of the present invention.

[0038] [ Figure 2 ] Figure 2 It shows the composition Figure 1 A three-dimensional view of the outline of the bubble generator in the microbubble generating device shown.

[0039] [ Figure 3 ] Figure 3 yes Figure 2 An exploded perspective view of the bubble generator shown.

[0040] [ Figure 4 ] Figure 4 It is shown Figure 3A three-dimensional view of the outline of a portion of the manifold shown.

[0041] [ Figure 5 ] Figure 5 It is shown Figure 4 The diagram shows a front view of the manifold configuration.

[0042] [ Figure 6 ] Figure 6 yes Figure 4 The cross-sectional view along line VI-VI is shown.

[0043] [ Figure 7 ] Figure 7 yes Figure 4 The cross-sectional view along line VII-VII is shown.

[0044] [ Figure 8 ] Figure 8 It is shown Figure 3 A three-dimensional view of the outline of the downstream inner tube section shown.

[0045] [ Figure 9 ] Figure 9 It is shown Figure 8 The diagram shows a front view of the downstream inner tube.

[0046] [ Figure 10 ] Figure 10 It is shown Figure 8 The diagram shows the bottom view of the downstream inner tube.

[0047] [ Figure 11 ] Figure 11 It is shown Figure 3 A three-dimensional view of the outline of the upstream inner tube section shown.

[0048] [ Figure 12 ] Figure 12 It is shown Figure 11 The diagram shows a front view of the upstream inner tube.

[0049] [ Figure 13 ] Figure 13 It is shown Figure 11 The diagram shows the bottom view of the upstream inner tube.

[0050] [ Figure 14 ] Figure 14 It is shown Figure 2 The diagram shows a front view of the bubble generator.

[0051] [ Figure 15 ] Figure 15 It is shown Figure 2 The diagram shows the bottom view of the bubble generator.

[0052] [ Figure 16 ] Figure 16 yes Figure 2 The cross-sectional view along the XVI-XVI line is shown.

[0053] [ Figure 17 ] Figure 17 yes Figure 2 The cross-sectional view along line XVII-XVII is shown.

[0054] [ Figure 18 ] Figure 18 It is shown Figure 1 A partially enlarged cross-sectional view showing the function of the microbubble generator.

[0055] [ Figure 19 ] Figure 19 This is a partially enlarged cross-sectional view showing the outline of a prior art microbubble generator. Detailed Implementation

[0056] Hereinafter, embodiments of the present invention will be described in detail using the accompanying drawings. Although the drawings will be used as needed for explanation, the illustrations are merely schematic and illustrative for the purpose of understanding the present invention, and the appearance, size, and proportions may differ from the actual object. Furthermore, although the following description focuses on specific embodiments, it is not limited to these embodiments.

[0057] (The overall structure of the microbubble generator) First, the overall structure of the microbubble generating device of this embodiment will be described. Figure 1 This diagram illustrates the usage state of a microbubble generator 1 according to an embodiment of the present invention, used in a beauty salon or similar setting. Figure 1 As shown, the microbubble generating device 1 includes a bubble generator 2 that generates microbubbles and discharges a gas-liquid mixture M containing microbubbles. The bubble generator 2 mixes liquid L with gas G, generating microbubbles internally. Figure 1 As shown, the bubble generator 2 is connected via piping 4 to a water valve 7, such as a tap water supply source, so that liquid L is continuously supplied. Additionally, the bubble generator 2 is connected via piping 5 to a compressor 8, such as a gas supply mechanism, so that pressurized gas G is supplied. Furthermore, the bubble generator 2 is connected via piping 6 to a discharge device such as a shower head 3, so that a gas-liquid mixture M containing microbubbles can be continuously discharged from the shower head 3.

[0058] Figure 18 This is a partially enlarged cross-sectional view illustrating the function of the microbubble generating device 1 in this embodiment. (As shown...) Figure 18As shown, the bubble generator 2 is assembled such that a downstream inner pipe 30 and an upstream inner pipe 50, both formed as separate components, are housed inside a cylindrical manifold 10. These two inner pipes serve as internal components of a flow path 70 that forms a flow of liquid L or gas G. A liquid inlet 20 is located at the upstream end of the manifold 10, with a liquid supply port 21 connected to a water valve via a piping 4. Conversely, a outlet 26 is located at the downstream end of the manifold 10, with an outlet 27 for discharging the gas-liquid mixture M generated inside the bubble generator 2. Furthermore, a gas inlet 14 with a gas supply port 15 is located on the main body 12 connecting the liquid inlet 20 and the outlet 26. Gas L is supplied to the interior of the manifold 10 from the gas supply port 15, which is connected to a compressor 8 via a piping 5.

[0059] like Figure 18 As shown, the internal space of the internal components (downstream inner tube 30 and upstream inner tube 50) constitutes a flow path 70. The flow path 70 extends from the upstream side of the upstream inner tube 50 to the downstream side of the downstream inner tube 30, with the axis Cz along the Z-axis as its center. That is, the center of the cross-section perpendicular to the Z-axis in the flow path 70 is approximately a straight line. Therefore, backflow and velocity reduction of the liquid L or gas-liquid mixture M flowing in the flow path 70 toward the flow direction F are suppressed, and smooth flow of the liquid L, etc., inside the flow path 70 is maintained. The flow path 70 has a first flow path section 71 that accelerates the flow velocity and a second flow path section 72 (gas-liquid mixing section) located downstream theredown for mixing the liquid G and gas G. It should be noted that, in this specification, downstream refers to the direction in which the liquid L and gas-liquid mixture M flow, and in the bubble generator 2, it refers to the side with the outlet 27 in the Z-axis direction. In addition, upstream refers to the source from which liquid L and gas-liquid mixture M flow, and in bubble generator 2, it refers to the side with liquid supply port 21 in the Z-axis direction.

[0060] like Figure 18As shown, the downstream diameter of the first flow path section 71 decreases and connects to the second flow path section 72. Therefore, the liquid L flowing in the first flow path section 71 is continuously supplied to the second flow path section while the flow rate increases. Furthermore, the second flow path section 72 expands in diameter downstream from the portion of the first flow path section 71 with the smallest inner diameter φ7. A through-hole 56 is provided near the downstream side of the portion of the first flow path section 71 with the smallest inner diameter φ7, connecting to the second flow path section 72 from the outside of the upstream inner tube 50. Gas G supplied from the gas inlet section 14 passes through the through-hole 56 and is supplied to the second flow path section 72 from the outside of the upstream inner tube 50. According to the Venturi effect, the liquid L becomes depressurized near the portion with the smallest inner diameter φ7. As a result, gas G is violently introduced into the second flow path section 72 from the through-hole 56, and then a strong swirling flow is generated in the first gas-liquid mixing section 24. Therefore, in the second flow path section 72, gas G and liquid L are thoroughly mixed to obtain a gas-liquid mixture M with a large number of bubbles.

[0061] The second flow path section 72 tapers in diameter further downstream, causing the gas-liquid mixture M to be in a depressurized state due to the Venturi effect. The downstream side of the second flow path section 72 has a minimum inner diameter φ5 and connects to the generation section 29. It should be noted that the minimum diameter φ5 at the second flow path section 72 is not particularly limited, but it is preferably smaller than the minimum diameter φ7 at the first flow path section 71. With this configuration, the gas-liquid mixture M can be forcefully supplied to the generation section 29. Furthermore, compared to the minimum diameter φ5 of the second flow path section 72, the inner diameter φ2 at the generation section 29 increases dramatically. This increases the pressure difference between the second flow path section 72 and the generation section 29, thus promoting the crushing and contraction of bubbles in the gas-liquid mixture M at the generation section 29, generating microbubbles.

[0062] (Overall structure of the bubble generator) Next, the structure of bubble generator 2 will be described in detail. Figure 2 This is a three-dimensional diagram that schematically shows the structure of bubble generator 2. (See diagram for example.) Figure 2 As shown, the bubble generator 2 has a liquid inlet 20 for supplying liquid into the interior and an outlet 26 for discharging the gas-liquid mixture to the exterior. Additionally, the bubble generator 2 has a main body 12 extending along the Z-axis and connecting the liquid inlet 20 and the outlet 20. The bubble generator 2 has a liquid supply port 21 at the liquid inlet 20 and a discharge port 27 at the outlet 26, and has a cylindrical structure connecting them with an axis Cz along the Z-axis as the central axis. Furthermore, the bubble generator 2 has a gas inlet 14 for supplying gas into the interior. The gas inlet 14 has a gas supply port 15 connected to the interior on a first surface 11b1 of the outer surface 11b of the main body 12, with an axis Cy along the Y-axis as the central axis. It should be noted that in the figures, the X-axis, Y-axis, and Z-axis are perpendicular to each other.

[0063] Figure 3 This is an exploded perspective view showing the structure of bubble generator 2. (See diagram below.) Figure 3 As shown, the bubble generator 2 has a manifold 10 with a cylindrical main body 12, and a downstream inner tube 30 and an upstream inner tube 50 housed inside the main body 12 about an axis Cz. The downstream inner tube 30 is connected to the outlet 26 inside the main body 12 by fitting with its downstream end 35. The upstream inner tube 50 is disposed inside the main body 12 upstream of the downstream inner tube 30, and the connecting end face 58 of the upstream connecting portion 57 is connected to the connecting end face 33 of the downstream connecting portion 32 of the downstream inner tube 30. In this embodiment, the manifold 10 functions as a sleeve that completely houses the downstream inner tube 30 and the upstream inner tube 50.

[0064] The materials of the manifold 10, downstream inner pipe 30, and upstream inner pipe 50 are not particularly limited, but are preferably materials that are not easily corroded by water. Furthermore, the manifold 10, downstream inner pipe 30, and upstream inner pipe 50 are preferably formed of a material with sufficient strength so that they will not break even if pressurized gas is introduced into the liquid flowing inside. Examples of materials for the manifold 10, downstream inner pipe 30, and upstream inner pipe 50 include rigid PVC (vinyl chloride resin), aluminum, and stainless steel (SUS), but stainless steel is particularly preferred. The manifold 10, downstream inner pipe 30, and upstream inner pipe 50 are preferably each integrally formed.

[0065] Figure 4 This is a perspective view showing the configuration of the manifold 10. The manifold 10 has a liquid inlet 20 with a liquid supply port 21 and a discharge port 26 with a discharge port 27. Additionally, the manifold 10 has a main body 12 connecting the liquid inlet 20 and the discharge port 27. The manifold 10 connects the liquid supply port 21 to the discharge port 27, forming a cylindrical structure with an inner surface 11a. In the main body 12, the gas supply port 15 of the gas inlet 14, which supplies gas to the interior, penetrates the pipe wall 10b (see reference). Figure 7 ).

[0066] like Figure 4 As shown, the outer surface 11b of the main body 12 and the liquid inlet 20 of the manifold 10 has a first surface 11b1, a second surface 11b2, a third surface 11b3, a fourth surface 11b4, a fifth surface 11b5, and a sixth surface 11b6, and has a generally regular hexagonal prism shape that is approximately long in the Z-axis direction from the first end surface 11b1 to the second end surface 11b2 (see reference). Figure 7 Therefore, the manifold 10 can be easily held in place with a wrench, hex wrench, etc.

[0067] like Figure 4As shown, a thread 22 is formed on the inner circumferential surface of the liquid inlet 20, so that it can be connected with... Figure 1 The pipe 4 shown is threaded. Additionally, the outlet portion 26 of the manifold 10 has a thread 28 on its outer peripheral surface and protrudes from the second end face 11b2 forming the regular hexagonal prism shape to the front end face 11c3, allowing it to connect with… Figure 1 The pipe 6 shown is threaded. A thread 16 is formed on the inner circumferential surface of the gas inlet 12, allowing it to connect with… Figure 1 The pipe shown is threaded. Therefore, it allows for easy connection with… Figure 1 The connection work for pipes 4, 5, 6, etc., is shown. It should be noted that in this embodiment, a chamfer is formed at the end in the Z-axis direction to facilitate holding with a hex wrench (see reference). Figure 5 ).

[0068] The manifold 10 has a depth D0 in the Y-axis direction (refer to...). Figure 7 ), Width W0 in the X-axis direction (refer to) Figure 5 ) and the length H0 in the Z-axis direction (refer to Figure 5 The depth D0, width W0, and length H0 are not particularly limited. For example, the depth D0 can be 20mm to 50mm, but from the viewpoint of reducing manufacturing costs, miniaturizing the product, and increasing product strength, it is preferably 22mm to 30mm. The depth D0 preferably corresponds to the existing wrench size. The width W0 preferably corresponds to the depth D0, so that its shape is a regular hexagon in plan view, and can be 23mm to 58mm. The length H0 can be 40mm to 170mm, but from the viewpoint of reducing manufacturing costs, miniaturizing the product, and increasing product strength, the length H0 is preferably 45mm to 65mm. In addition, when the pressure of the liquid supplied to the interior and the pressure of the pressurized gas are high, the depth D0, width W0, and length H0 can be further increased according to the aforementioned pressure.

[0069] Figure 5 and Figure 6 The length H1 of the liquid inlet portion 20 from the first end face 11b1 to the stop face 11a0 is not particularly limited and can be 7mm to 25mm. From the viewpoint of reducing manufacturing costs, miniaturizing the product, and improving product strength, the length H1 is preferably 8mm to 12mm. Furthermore, the length H2 of the main body portion 12 from the stop face 11a0 to the second end face 11b2 is not particularly limited and can be 20mm to 120mm. From the viewpoint of reducing manufacturing costs, miniaturizing the product, and improving product strength, the length H2 is preferably 30mm to 40mm.

[0070] like Figure 5As shown, in this embodiment, the front end face 11c3 of the outlet portion 26 is located at a position protruding from the second end face 11c2, which is slightly hexagonal in shape, in the Z-axis direction with a length H3. The protruding length H3 of the outlet portion 26 is not particularly limited and can be 7mm to 25mm. From the viewpoints of reducing manufacturing costs, miniaturizing the product, improving product strength, and generating fine bubbles effectively, the length H3 is preferably 8mm to 12mm. It should be noted that when the pressure of the liquid supplied to the interior and the pressure of the pressurized gas are high, the lengths H1, H2, and H3 can be further increased according to the depth D0, width W0, and length H0.

[0071] like Figure 6 As shown, the manifold 10 has an inner surface 11a1 of the main body portion forming a cylindrical interior 10a extending along the Z-axis direction and an inner surface 11a3 of the outlet portion (see reference). Figure 7 ).like Figure 6 and Figure 7 As shown, in this embodiment, the inner diameter φ2 of the outlet portion 26 is smaller than the inner diameter φ1 of the interior 10a in the main body portion 12, but the inner diameters φ1 and φ2 are not particularly limited. However, the inner diameter φ1 in the main body portion 12 is preferably a size that can accommodate the internal components (downstream inner tube 30 and upstream inner tube 50) inside the interior 10a of the manifold 10 and allow the downstream inner tube 30 and upstream inner tube 50 to be embedded. For example, the inner diameter φ1 can be 10mm to 25mm, and is preferably 15mm to 20mm. In addition, the inner diameter φ2 at the outlet portion 26 is preferably a size that allows the downstream end 35 of the downstream inner tube 30 to be embedded. For example, the inner diameter φ2 can be 8mm to 20mm, and is preferably 12mm to 18mm. Figure 7 The wall thickness D1 of the manifold 10 shown is not particularly limited. For example, the wall thickness D1 of the manifold 10b can be 2 mm to 12 mm. From the viewpoint of reducing manufacturing costs, miniaturizing the product, and improving product strength, the wall thickness D1 of the manifold 10b is preferably 3 mm or more. It should be noted that when the pressure of the liquid supplied to the inside and the pressure of the pressurized gas are high, the inner diameter φ1, φ2, and wall thickness D1 can be further increased according to the depth D0, width W0, and length H0.

[0072] like Figure 6 As shown, the inner surface 11a1 of the main body is connected to a stop surface 11a0 that is substantially perpendicular to it. The inner surface 11a1 of the main body and the inner surface 11a3 of the outlet are connected by a positioning surface 11a2 that is perpendicular to them. The stop surface 11a0 defines the downstream position where the aforementioned pipe 4 can be inserted. The positioning surface 11a2 is connected to the stepped surface 38 of the downstream inner pipe 30 (see reference 11a0). Figure 9 The contact allows for the positioning of the downstream inner tube 30.

[0073] like Figure 8 As shown, the downstream inner tube 30 has a tube wall 31 that extends approximately along the Z-axis and has an outer surface 31b and an inner surface 31a, and has a generally tubular shape about the axis Cz. Additionally, as... Figure 9 As shown, the downstream inner tube 30 generally has a downstream end 35 located on the downstream side, a downstream connecting portion 32 located on the upstream side, and a downstream reduced diameter portion 34 located between the downstream end 35 and the downstream connecting portion 32.

[0074] like Figure 9 As shown, the first portion 31a1, which serves as the inner surface 31a at the downstream connecting portion 32, extends with a length H4 in the Z-axis direction. Additionally, the third portion 31a3, which also serves as the inner surface 31a at the downstream end 35, extends with a length H6 in the Z-axis direction. The inner diameter φ5 at the downstream end 35 of the downstream inner tube 30 is smaller than the inner diameter φ6 at the downstream connecting portion 32 of the downstream inner tube 30. Furthermore, the downstream diameter reduction portion 34 has a length H5 in the Z-axis direction, and the second portion 31a2, which serves as the inner surface 31a at the downstream diameter reduction portion 34, is continuously connected from the first portion 31a toward the third portion 31a3 in an arc-like manner. The inner diameter of the downstream diameter reduction portion 34 of the downstream inner tube 30 decreases from the downstream connecting portion 32 toward the downstream end 35.

[0075] Figure 9 The thickness D2 of the pipe wall 31 at the downstream connection 32 shown is not particularly limited, but from the viewpoint of ease of assembly and product strength, it is preferably 2 mm or more. Figure 9 and Figure 10 The diameter φ3 of the downstream inner tube 30 shown is preferably designed to be the same as or less than the inner diameter φ1 of the inner tube 10a in the manifold 10, so that the downstream inner tube 30 can be embedded into the manifold 10 (see reference). Figure 7 ).

[0076] like Figure 9 As shown, the connecting end face 33 of the downstream connecting portion 32 of the downstream inner tube 30 is perpendicular to the Z-axis direction, and the front end portion 36 of the downstream end portion 35 is configured and connected to the outlet portion 26 (see reference). Figure 6 The internal structure of the manifold 10 is highlighted. The front end 36 has a front outer surface 37 formed along the inner surface 11a3 of the outlet and an end face 39 perpendicular to the front outer surface 37. The outer surface 31b and the front outer surface 37 are connected by a stepped surface 38 perpendicular to them. The stepped surface 38 of the downstream end 35 abuts against the positioning surface 11a2 of the manifold 10. In addition, the corner where the stepped surface 38 intersects with the outer surface 31b is preferably chamfered to facilitate the insertion of the downstream inner tube 30 from the liquid supply port 21 of the manifold 10 into the interior 10a.

[0077] In order to Figure 9 and Figure 10 The front end 36 of the downstream end 35 shown can be fitted into the outlet 26. The diameter φ4 at the front end 36 is preferably designed to be the same as or less than the inner diameter φ2 of the interior 10a of the outlet 26 (see reference). Figure 4 The protruding length H12 of the front end portion 36 is not particularly limited, but from the viewpoint that the front end portion 36 is fitted into and fixed to the outlet portion 26, it is preferably 0.5 mm or more. In addition, in order to facilitate the fitting of the front end portion 36 of the downstream end portion 35 into the outlet portion 26, the corner where the front outer surface 37 intersects with the end face 39 is preferably chamfered.

[0078] Figure 9 The inner diameter φ6 at the downstream connection 32, the inner diameter φ5 at the downstream end 35 of the downstream inner tube 30, and the radius of the arc formed by the second portion 31a2 of the inner surface 31a are not particularly limited. From the viewpoint of ease of manufacture, product miniaturization, and good mixing of gas and liquid, the inner diameter φ6 is preferably 8mm to 20mm, more preferably 10mm to 15mm. From the viewpoint of ease of manufacture, product miniaturization, and good mixing of gas and liquid, the inner diameter φ5 is preferably 3mm to 15mm, more preferably 5mm to 8mm. From the viewpoint of ease of manufacture, product miniaturization, and good mixing of gas and liquid, Figure 9 The radius of the arc formed by the second part 31a2 shown can be 15mm to 20mm, preferably 16mm to 18mm. It should be noted that the second part 31a2 of the inner surface 31a can be a straight line connecting the first part 31a to the third part 31a3 without forming an arc. Furthermore, when the pressure of the liquid supplied to the interior or the pressure of the pressurized gas is high, the radius of the arc formed by the inner diameters φ6 and φ5 and the second part 31a2 can be further increased based on the depth D0, width W0, and length H0.

[0079] Figure 9The lengths H4 of the downstream connecting portion 32, H5 of the downstream constricted portion 34, and H6 of the downstream end portion 35 are not particularly limited. However, if the downstream inner tube 30 becomes longer overall in the Z-axis direction, it becomes difficult to insert and assemble the downstream inner tube 30 into the manifold 10. Furthermore, if the downstream inner tube 30 is relatively short overall, it is impossible to adequately ensure gas-liquid mixing in the gas-liquid mixing section (second flow path portion 72). Therefore, the lengths H4, H5, and H6 can be appropriately designed from these perspectives; for example, the length H4 can be 1 mm to 15 mm, the length H5 can be 7 mm to 20 mm, and the length H6 can be 2 mm to 15 mm. Preferably, the length H4 is 1 mm to 5 mm, the length H5 is 5 mm to 12 mm, and the length H6 is 2 mm to 5 mm. It should be noted that when the pressure of the liquid supplied to the interior and the pressure of the pressurized gas are relatively high, the lengths H4, H5, H6, H12, and D2 can be further increased based on the depth D0, width W0, and length H0.

[0080] like Figure 11 As shown, the upstream inner tube 50 generally has a roughly tubular shape with axis Cz as its central axis. Figure 12 As shown, the thickness D3 of the upstream inner tube 50 from its outer surface 51b to its inner surface 51a is approximately constant, and it has a shape that narrows in such a way that the inner diameter φ7 at the narrowing portion 60 is smaller than the inner diameter φ8 at both ends in the Z-axis direction and becomes the smallest inner diameter in the upstream inner tube 50. The thickness D3 of the tube wall 51 is not particularly limited, but preferably the thickness D2 of the tube wall 31 at the downstream connection portion 32 of the downstream inner tube 30 (refer to...) Figure 9 The diameters at both ends of the upstream inner tube 50 in the Z-axis direction are preferably equal to the diameter φ3 of the downstream inner tube 30, and are preferably designed to be the same as or less than the inner diameter φ1 of the inner tube 10a in the manifold 10, so that it can be embedded in the manifold 10 (see reference). Figure 7 Additionally, the upstream inner tube 50 generally has an upstream end 52, an upstream reduced diameter portion 54, an expanded diameter portion 55, and an upstream connecting portion 57.

[0081] like Figure 12As shown, the first portion 51a1 at the upstream end 52, which serves as the inner surface 51a, extends along the Z-axis with a length H7. Furthermore, the fourth portion 51a4 at the upstream connecting portion 57, which also serves as the inner surface 51a, extends along the Z-axis with a length H10. Additionally, the upstream-side tapered portion 54 has a length H8 along the Z-axis, and the second portion 51a2 at the upstream-side tapered portion 54, which serves as the inner surface 51a, is continuously connected from the first portion 51a1 toward the narrowed portion 60, which has the minimum inner diameter φ7. The inner diameter of the upstream-side tapered portion 54 of the upstream inner tube 50 decreases in diameter from the upstream end 52 toward the narrowed portion 60. Furthermore, the expanding portion 55 has a length H9 along the Z-axis, and the third portion 51a3 at the expanding portion 55, which serves as the inner surface 51a, is continuously connected from the narrowed portion 60 toward the upstream connecting portion 57. The inner diameter of the expanding portion 55 of the upstream inner tube 50 increases in diameter from the narrowed portion 60 toward the upstream connecting portion 57.

[0082] like Figure 13 As shown, the upstream inner tube 50 has multiple through holes 56. Each through hole 56 is rotationally symmetrical about the axis Cz, and is evenly distributed in the enlarged diameter section 55 at 90° intervals. Figure 12 As shown, the through hole 56 penetrates the pipe wall 51 from the outer surface 51b of the enlarged diameter portion 55 toward the third portion 51a3 of the inner surface, with its central axis Cg inclined at an angle θ1 relative to the axis Cz. Furthermore, the through hole 56 is formed such that its center O1 in the outer surface 51b is located downstream of position C0 on the Z-axis of the narrowed portion 60 at a distance H11 in the Z-axis direction. The length H11 can be, for example, 5 mm or less. Additionally, the inner diameter φ9 of the through hole 56 is not particularly limited, but is preferably smaller than the minimum inner diameter φ7 of the upstream inner pipe 50, for example, it can be 2 mm to 7 mm. The angle θ1 is not limited, but is preferably 20° to 50°.

[0083] like Figure 12 As shown, the connecting end face 58 of the upstream connecting portion 57 and the end face 53 of the upstream end portion 52 of the upstream inner tube 50 are perpendicular to the Z-axis direction. The connecting end face 58 of the upstream connecting portion 57 abuts against the connecting end face 33 of the downstream connecting portion 32. The end face 53 of the upstream end portion 52 intersects the outer surface 51b approximately perpendicularly. On the other hand, in order to facilitate the insertion of the upstream inner tube 50 from the liquid supply port 21 of the manifold 10 into the interior 10a, it is preferable that the corner where the connecting end face 58 of the upstream connecting portion 57 intersects the outer surface 51b is chamfered.

[0084] Figure 12 The inner diameter φ8 of the upstream connecting portion 57 and the upstream end portion 52 of the upstream inner tube 50 shown is not particularly limited. The inner diameter φ8 at the upstream end portion 52 can be designed to have the same value as the inner diameter φ6 at the downstream connecting portion 32, and preferably is equal to the inner diameter φ6 at the downstream connecting portion 32 (see reference). Figure 9 With this configuration, when the upstream connecting portion 57 is connected to the downstream connecting portion 32 inside the manifold 10, the fourth portion 51a4 of the inner surface of the upstream connecting portion 57 and the first portion 31a1 of the inner surface of the downstream connecting portion 32 will be substantially the same surface. "Substantially the same surface" means that as long as the surface is smooth enough not to reduce the flow rate of the liquid flowing inside the internal components, even the presence of slight steps is acceptable. In this specification, "substantially the same surface" also includes the case where there are steps of 0.5 mm or less between the fourth portion 51a4 of the inner surface of the upstream connecting portion 57 and the first portion 31a1 of the inner surface of the downstream connecting portion 32.

[0085] Figure 12 The inner diameter φ7 at the narrowing section 60 shown is preferably larger than the inner diameter φ5 at the downstream end 35 of the downstream inner tube 30 (refer to...). Figure 9 For example, from the viewpoints of ease of manufacture, miniaturization of the product, and good mixing of gas and liquid, the inner diameter φ7 is preferably 5mm to 20mm, more preferably 6mm to 10mm.

[0086] Figure 12 The lengths H7 of the upstream end 52, H8 of the upstream narrowing portion 54, H9 of the expanding portion 55, and H10 of the upstream end 37 are not particularly limited. However, if the upstream inner tube 50 becomes longer overall in the Z-axis direction, it will be difficult to insert and assemble the upstream inner tube 50 into the manifold 10. Furthermore, if the upstream inner tube 50 is longer than the outer diameter of the narrowing portion 60, the strength of the periphery of the narrowing portion 60 will decrease. The lengths H7, H8, H9, and H10 can be appropriately designed from these perspectives. For example, the length H7 can be 1 mm to 15 mm, the length H8 can be 4 mm to 20 mm, the length H9 can be 4 mm to 20 mm, and the length H10 can be 1 mm to 15 mm. Preferably, the length H7 is 1 mm to 5 mm, the length H8 is 7 mm to 12 mm, the length H9 is 7 mm to 12 mm, and the length H10 is 1 mm to 5 mm. It should be noted that when the pressure of the liquid supplied to the interior and the pressure of the pressurized gas are relatively high, the lengths H7, H8, H9, H10, H11, and D3 can be further increased based on the depth D0, width W0, and length H0.

[0087] Figure 14 This is a front view showing the configuration of the bubble generator 2 after the manifold 10 and internal components (downstream inner tube 30 and upstream inner tube 50) are assembled. Figure 14As shown, the minimum inner diameter φ0 in the liquid inlet 20 is greater than the diameter φ3 of the internal component. Therefore, the internal component can be inserted from the liquid supply port 21 of the liquid inlet 20. When assembling the bubble generator 2, first, the downstream inner tube 30 is inserted from the liquid supply port 21, and then the upstream inner tube 50 is inserted, thereby assembling the bubble generator 2, wherein the downstream inner tube 30 and the upstream inner tube 50 are housed inside the manifold 10.

[0088] Figure 17 This is a cross-sectional view of the bubble generator 2 after the manifold 10 and internal components (downstream inner pipe 30 and upstream inner pipe 50) are assembled. The liquid inlet 20, gas inlet 14, and outlet 26 are threaded. The microbubble generator 1 can be assembled by connecting the liquid inlet 20 to the water valve 7 via the piping 4, the gas inlet 14 to the compressor 8 via the piping 5, and the outlet 26 to the shower head 7. This microbubble generator 1 not only has low manufacturing costs but also reduces maintenance costs.

[0089] like Figure 17 As shown, the inner diameter φ2 at the outlet 26 is larger than the minimum inner diameter φ5 in the downstream inner tube 30. Furthermore, the end face 39 of the front end 36 is perpendicular to the axis Cz of the flow path 70. That is, the diameter φ5 on the downstream side of the flow path 70 rapidly expands to a diameter φ2 in the generation section 29. Additionally, the point in the downstream inner tube 30 where the minimum inner diameter φ5 is located is at the most downstream front end 36, and the minimum inner diameter φ5 is smaller than the minimum inner diameter φ7 of the upstream inner tube 50. Therefore, the gas-liquid mixture flows fastest through the front end 36 of the downstream inner tube 30 in the flow path 70, resulting in a depressurized state. Thus, the gas-liquid mixture continuously flowing in the flow path 70 is rapidly pressurized in the generation section 29 of the outlet 26, thereby better crushing the bubbles contained in the liquid, resulting in a gas-liquid mixture with microbubbles having a diameter in the nanometer range (less than 1 μm).

[0090] like Figure 17 As shown, the internal component has an upstream diameter reduction section 54, where the first flow path portion 71, with a diameter of φ8 at the most upstream side of the flow path 70, is reduced to a minimum diameter of φ7. Additionally, the internal component has an expansion section 55, where the second flow path portion 72 of the flow path 70 is expanded to a diameter of φ6. Therefore, in the flow path 70 surrounding the narrowing section 60, the liquid is accelerated and depressurized, thus enabling efficient introduction of gas into the second flow path portion 72 of the liquid flow path 70.

[0091] like Figure 14 As shown, the downstream inner pipe 30 and the upstream inner pipe 50 are arranged side by side in the Z-axis direction with the same central axis Cz inside the manifold 10. Figure 15As shown, the flow path 70 within the internal components extends to the outlet 27 of the outlet section 26 with the same axis Cz as its center. Therefore, the flow velocity of the gas-liquid mixture flowing within the flow path 70 is maintained at a high level, and the gas-liquid mixture discharged through the outlet section 26 can also have suitable hydraulic pressure. It should be noted that, as... Figure 17 As shown, the manifold 10 and its internal components are preferably designed such that the narrowed portion 60 of the upstream inner tube 50 is positioned in the XY plane of the gas supply port 15, which has a central axis Cy. This configuration allows for the efficient introduction of gas into the liquid flow path.

[0092] Figure 16 This is a cross-sectional view of the gas supply port 15 in the XY plane with its central axis Cy. (Example) Figure 16 As shown, a gap 80 is formed between the outer surface 51b and the inner surface 11a1 of the main body of the manifold 10, such that it surrounds the outer surface 51b of the narrowed portion 60 of the upstream inner tube 50 circumferentially. Furthermore, all the through holes 56 extend from the gap 80 to the flow path 70. Therefore, the gas supplied from the gas supply port 15 to the interior of the manifold 10 is supplied to all the through holes 56 via the gap 80, and then to the flow path 70 via all the through holes 56. Each through hole 56 is equally arranged, the central axis Cg of the through hole 56 is inclined relative to the central axis Cz of the flow path, and penetrates the pipe wall 51 of the expanded diameter portion 55 (see reference). Figure 12 With this configuration, the gas introduced into the flow path 70 is more violently introduced from the through holes 56. By supplying gas from all the through holes 56 in this way, a strong swirling flow is well generated in the second flow path section 72, thus obtaining a gas-liquid mixture with a large number of bubbles. Therefore, in this embodiment, the gas-liquid mixture discharged from the microbubble generator can contain a higher concentration of microbubbles.

[0093] In addition, such as Figure 17 As shown, the downstream inner tube 30 is configured such that the stepped surface 38 abuts against the positioning surface 11a2 of the manifold 10. Furthermore, the upstream inner tube 50 is configured such that the end face 53 of the upstream end 52 is flush with the stop surface 11a0 of the manifold 10. With this configuration, the internal components (upstream inner tube 50 and downstream inner tube 30) are completely contained within the manifold 10 as a sleeve. Therefore, if the bubble generator 2 is connected to pipes 4, 5, and 6, no internal components are exposed outside the manifold 10, significantly improving the product strength of the bubble generator 2 (see reference). Figure 18 ).

[0094] Furthermore, such as Figure 17 As shown, since the end face 53 of the upstream end 52 is approximately flush with the stop face 11a0 of the manifold 10, liquid is difficult to enter between the manifold 10 and the upstream end 52, thus improving product strength. Figure 18As shown, if the pipe 4 is threadedly connected to the manifold 10 such that its end abuts against each of the end face 53 and the stop face 11a0, the strong connection formed by the threaded connection between the pipe 4 and the manifold 10 can make the internal components more securely housed in the manifold 10. Furthermore, as... Figure 17 As shown, the connecting end face 58 of the upstream inner tube 50 and the connecting end face 33 of the downstream inner tube 30 are internally connected further downstream of the gas supply port 15 of the manifold 10. Connecting the upstream inner tube 50 and the downstream inner tube 30 at this location facilitates assembly and ensures product strength. It should be noted that regarding the connection between the upstream inner tube 50 and the downstream inner tube 30, even if the connecting end faces do not directly contact each other, as long as the connection forms a gap that prevents leakage of the gas-liquid mixture from the flow path, it is sufficient. For example, the connection can be made using adhesives, gaskets, etc., to improve airtightness. Alternatively, other tubular components can be arranged therein to indirectly connect the upstream inner tube 50 and the downstream inner tube 30.

[0095] Figure 17 This is a cross-sectional view of the YZ plane of flow path 70 with its central axis Cz. (Example) Figure 17 As shown, the downstream inner tube 30 is connected to the outlet portion 26 of the manifold 10 by fitting together with the front end portion 36 of the downstream end portion 35. This configuration creates a strong connection between the outlet portion 26 and the downstream inner tube 30, improving the pressure resistance of the bubble generator 2. Furthermore, the fitting facilitates the positioning of internal components, making assembly easier. Additionally, the outer surface 37 of the front end portion 36 abuts against the inner surface 11a3 of the outlet portion. Furthermore, the stepped surface 38 of the downstream inner tube 30 abuts against the positioning surface 11a2. Further, the outer surface 31b of the downstream inner tube 30 abuts against the inner surface 11a1 of the main body. Therefore, except for the chamfered portion, the downstream inner tube 30 is substantially seamlessly embedded in the manifold 10, thereby strengthening the connection between the manifold 10 and the downstream inner tube 30 and improving product strength.

[0096] like Figure 17As shown, the connecting end face 33 of the downstream connecting portion 32 and the connecting end face 58 of the upstream connecting portion 57 are substantially perpendicular to the axis Cz of the flow path 70. This configuration facilitates the assembly of internal components, and the connecting end faces can be connected to each other substantially without gaps, except for the chamfered portion, resulting in excellent pressure resistance. Furthermore, since the downstream connecting portion 32 is connected to the upstream connecting portion with its inner surface first portion 31a1 and the inner surface fourth portion 51a4 of the upstream connecting portion 57 being substantially coplanar, the pressure resistance of the microbubble generator can be improved. Additionally, the outer surface 51b of the upstream connecting portion 57 and the outer surface 51b of the upstream end 52 of the upstream inner tube 50 abut against the inner surface 11a1 of the main body. Therefore, the downstream inner tube 50 is embedded into the manifold 10 substantially without gaps, except for the chamfered portion and the gap 80, thereby strengthening the connection between the manifold 10 and the upstream inner tube 50 and improving product strength.

[0097] It should be noted that in this embodiment, the manifold 10 is connected to the internal components (downstream inner tube 30 and upstream inner tube 50) by embedding, but adhesives or the like can also be used for fixation. However, from the viewpoint of eliminating the possibility of adhesive fragments or the like mixing into the gas-liquid mixture, it is preferable not to use adhesives or the like, but to design them to be of appropriate size so that sufficient fixation strength can be obtained by embedding the internal components into the manifold 10.

[0098] As described above, the microbubble generator 1 can mix pressurized gas with liquid flowing in the flow path 70 inside the bubble generator 2, and efficiently discharge a gas-liquid mixture containing microbubbles with nanometer-sized diameters. That is, the gas-liquid mixture flowing from the flow path 70 generates microbubbles in the generation section 29. The flow path 70 can be easily formed by using the manifold 10 as a sleeve, inserting the downstream inner tube 30 and the upstream inner tube 50 from the liquid supply port 21. Therefore, the bubble generator 2 is easy to assemble. Furthermore, the downstream inner tube 30 and the upstream inner tube 50 can form a strong connection inside the manifold 10, thus providing excellent resistance not only to external impacts but also to the pressure resistance of the fluid flowing in the flow path.

[0099] This invention is not limited to the above-described embodiments, and its technical scope also includes various design modifications that do not depart from the inventive spirit described in the claims.

[0100] The size and number of through holes of the microbubble generator can be appropriately varied according to factors such as the liquid flow rate, the diameter of the flow path, and the pressure of the mixed gas. For example, in applications such as agriculture where a microbubble generator is needed to discharge a gas-liquid mixture containing a large number of microbubbles, it can be a bubble generator with a length H0 exceeding 30 cm and a width W0 exceeding 15 cm. It should be noted that, provided sufficient product strength can be ensured, the length H0 can be increased relative to the width W0 to ensure that the gas-liquid mixing section 72 is longer.

[0101] In addition, in the above embodiment, the internal components are divided into two parts: the upstream inner tube and the downstream inner tube. However, they can also be divided into three or more parts and housed inside the manifold.

[0102] Next, the manufacturing method of the microbubble generating device 1 in the embodiments of the present invention will be described.

[0103] In this manufacturing method, the manifold 10, the downstream inner tube 30, and the upstream inner tube 50 are each formed as independent components. Then, in the assembly process, the downstream inner tube 30 and the upstream inner tube 50 are housed in the manifold 10 for assembly. That is, the manufacturing method includes: a step of forming a manifold 10 as an independent component, the manifold 10 having a liquid inlet 20 for supplying liquid to the interior, a gas inlet 14 for supplying gas to the interior, and an outlet 26 for generating microbubbles and discharging a gas-liquid mixture containing microbubbles; a step of forming a downstream inner tube 30 as an independent component, the downstream inner tube 30 being disposed downstream in the direction of liquid flow; a step of forming an upstream inner tube 50 as an independent component, the upstream inner tube 50 being disposed upstream in the direction of liquid flow and having a through hole 56 for introducing gas supplied from the gas inlet 14; and a step of assembling and accommodating the downstream inner tube 30 and the upstream inner tube 50 communicating with the downstream inner tube 30 inside the formed manifold 10 in such a way that the formed upstream inner tube 50 and the formed downstream inner tube 30 are coaxially arranged to form a flow path for allowing liquid supplied from the liquid inlet 20 to flow to the outlet 26.

[0104] According to the microbubble generator 1 manufactured by this method, a liquid-gas mixture flowing in the flow path inside the bubble generator 2 can be efficiently discharged, containing microbubbles with nanometer-sized bubble diameters. The bubble generator 2 is configured such that a manifold 10, formed as a separate component, serves as a sleeve, and internal components are arranged inside it. The internal components are assembled by housing and connecting an upstream inner tube 50 and a downstream inner tube 30, both formed as separate components, inside the manifold 10. Assembly operations such as inserting long tubular components into the interior of other tubular components are very cumbersome, but by dividing the internal components, assembly becomes easier. Furthermore, by connecting the upstream inner tube 50 and the downstream inner tube 30 inside the manifold 10, pressure resistance is also ensured. Furthermore, since the bubble generator 2 is constructed by housing internal components inside the manifold 10, product strength is improved, and connection to piping is easy. Therefore, the microbubble generator 1 not only has low manufacturing cost, but also reduces maintenance costs.

[0105] The downstream inner tube forming process preferably includes a process of forming a downstream inner tube 30, which has a downstream connecting portion 32 connected to the upstream inner tube 50, a downstream end portion 35 connected to the interior of the outlet portion 26, and a downstream diameter reduction portion 34 whose inner diameter decreases from the downstream connecting portion 32 toward the downstream end portion 35. The upstream inner tube forming process preferably includes a process of forming an upstream inner tube 50 and distributing a through hole 56 in an expansion portion 55, which has an upstream diameter reduction portion 54 whose inner diameter decreases toward the downstream side, an expansion portion 55 whose inner diameter increases from the upstream diameter reduction portion 54 toward the downstream side, and an upstream connecting portion 57 connected to the downstream connecting portion 32.

[0106] The downstream inner tube forming process or the upstream inner tube forming process preferably includes a process in which the minimum inner diameter of the downstream inner tube 30 is smaller than the minimum inner diameter of the upstream inner tube 50, and the manifold forming process preferably includes a process in which the outlet portion 26 has a portion that is at least larger than the minimum inner diameter of the downstream inner tube 30.

[0107] The assembly process preferably includes a process in which the downstream end 35 of the downstream inner tube 30 is fitted and connected to the outlet portion 26 of the manifold 10.

[0108] The assembly process preferably includes a process in which the central axis of the flow path 70 in the downstream diameter reduction section 34 of the downstream inner tube 30 and the central axis of the flow path 70 in the upstream diameter reduction section 54 of the upstream inner tube 50 are arranged coaxially.

[0109] The assembly process preferably includes connecting the inner surface of the downstream connecting portion 32 of the downstream inner tube 30 to the upstream connecting portion 57 in such a way that the inner surface of the upstream connecting portion 57 of the upstream inner tube 50 is substantially the same as the inner surface of the upstream connecting portion 57 of the upstream inner tube 50.

[0110] The assembly process preferably includes a process in which the downstream connecting portion 32 of the downstream inner tube 30 and the upstream connecting portion 57 of the upstream inner tube 50 are connected to each other by end faces 33 and 53 that are substantially perpendicular to the central axis of the flow path 70 in the upstream diameter reduction portion 54 of the upstream inner tube 50.

[0111] The upstream inner tube forming process preferably includes forming the upstream inner tube 50 by having the through hole 56 inclined relative to the central axis of the flow path 70 in the upstream reduced diameter portion 54 and passing through the tube wall of the expanded diameter portion 55.

[0112] The upstream inner tube forming process preferably includes the process of forming a plurality of through holes 56 evenly arranged in the circumferential direction of the enlarged diameter portion 55.

[0113] The assembly process preferably includes assembling the pipe by forming a gap 80 between the outer surface of the upstream reduced diameter portion 54 and the expanded diameter portion 55 of the upstream inner tube 50 and the inner surface of the manifold 10, so that the plurality of through holes 56 extend from the gap to the flow path 70.

[0114] The manifold forming process preferably includes forming threads 22, 16 and 28 for threaded connection with other pipes in the liquid inlet 20, gas inlet 14 and outlet 26 respectively.

[0115] Example The present invention will be further described in detail below by way of examples, but the present invention is not limited to these examples.

[0116] [Example] 1. Determination of particle size, etc., of microbubbles contained in gas-liquid mixtures (1) A gas-liquid mixture M is generated using the microbubble generator 1 of the present invention, and the particle size distribution of the microbubbles contained in the gas-liquid mixture M is measured. It should be noted that a nanoparticle analysis system (model: NanoSight NS300, Malvern, UK) is used to measure the particle size distribution of the microbubbles. The microbubble generator 1 uses... Figure 1 The apparatus involved in the embodiment shown is connected to a bubble generator 2, a compressor 8 which serves as a gas supply mechanism, and a shower head 3 for measurement.

[0117] Specifically, Figure 2 The manifold 10, downstream inner tube 30, and upstream inner tube 50 shown are assembled to function as a bubble generator 2. The manifold 10 of the bubble generator 2 has... Figures 4-7 The tube shown is roughly hexagonal prism in shape and is made of stainless steel with a length H0 (total length) of 55 mm, a depth D0 of 25 mm, a length H1 of 10 mm for the liquid inlet 20, a length H2 of 35 mm for the main body 12, a protruding length H3 of 10 mm for the outlet 26, an inner diameter φ1 of 18 mm for the inner diameter φ2 of the inner diameter φ2 of the outlet 26, an internal thread 22 of G1 / 2 (JIS standard) for the liquid inlet 20, and an external thread 28 of G1 / 2 (JIS standard) for the outlet 26. The manifold 10 is manufactured by forming a gas inlet 14 with an internal thread 16 of Rc1 / 8 (JIS standard) on the main body 12 of this stainless steel tube.

[0118] In addition, as the downstream inner tube 30, it has Figures 8-10 The tube shown has a cylindrical shape and is made of stainless steel with a diameter of φ3 of 18 mm, a length of H4 of the downstream connecting part 32 of 2 mm, a length of H5 of the downstream side narrowing part 34 of 10 mm, a length of H6 of the downstream end 35 of 3 mm, a diameter of φ4 of 14 mm at the front end 36, an inner diameter of φ6 of 13 mm at the downstream connecting part 32, an inner diameter of φ5 of 6.5 mm at the downstream end 35, and a radius of 17.01 for the arc formed by the second part 31a of the inner surface 31a.

[0119] In addition, as the upstream inner tube 50, it has Figures 11-13 The tube shown has a cylindrical shape and is made of stainless steel with a diameter of φ3 of 18 mm and a wall thickness of D3 of 2.5 mm. It is processed to have a length of H7 of 2 mm for the upstream end 52, a length of H8 of 8 mm for the upstream side reduced diameter portion 54, a length of H9 of 8 mm for the expanded diameter portion 55, a length of H10 of 2 mm for the upstream connecting portion 57, an inner diameter of φ8 of 13 mm for the upstream end 52 and the upstream connecting portion 57, a minimum inner diameter of φ7 of 8 mm, an inner diameter of φ9 of 3 mm for each of the four through holes 56, an inclination angle θ1 of 30° for each through hole 56, and a distance H11 of 2 mm between the center O1 of the outer surface 51b of the through hole 56 and the position C0 of the minimum inner diameter φ7.

[0120] Additionally, the compressor 8 uses an air compressor SR-045 (Fujiwara Sangyo Co., Ltd. product, model: SRL04SPT-01), which is connected to the bubble generator 2 via piping 5. The water valve 7 uses a tap, with a hose directly connected to the tap and then connected to the bubble generator 2 via piping 4. The shower head 3 uses a shower head with a spray nozzle diameter as small as 0.3mm (Arromic Co., Ltd. product, product name: Pro Shower Clear ProC-48N).

[0121] As experimental conditions, the pressurized gas G is air, and the pressure of the pressurized gas generated by the compressor is set to 0.19 MPa. In addition, the water pressure of the liquid L (i.e., water) supplied from the water valve 6 to the bubble generator 2 is set to 0.15 MPa, and the water flow rate is set to 20 L / min.

[0122] [Comparative Example] 2. Determination of particle size, etc., of microbubbles contained in gas-liquid mixtures (2) As a comparative example, using the prior art microbubble generating apparatus described in Patent Document 1, a gas-liquid mixture M was generated under the same experimental conditions as in the example, and the particle size distribution of the microbubbles contained in the gas-liquid mixture M was measured. In the comparative example, the prior art microbubble generating apparatus described in Patent Document 1 was used... Figure 19 The microbubble generator 101 shown.

[0123] Specifically, the bubble generator 102 of the microbubble generating device 101 has a first tubular body 130 made of a rigid PVC tube with a diameter φ103 of 18 mm, an inner diameter φ108 of 13 mm, and a wall thickness of 2.5 mm, and a second tubular body 150 made of a rigid PVC tube with an outer diameter of 24 mm, an inner diameter φ102 of 18 mm, and a wall thickness of 3 mm. The total length H100 of the bubble generator 102 is 20.6 cm. The first tubular body 130 is formed by deep drawing the outer periphery until the minimum inner diameter φ107 of the upstream tapering section reaches 8 mm, and after deep drawing the outer periphery of the downstream PVC tube, the tube is cut to present an end with a minimum inner diameter φ105 of 6.4 mm. In addition, four through holes 156 with a diameter of 2.5 mm are formed at approximately 90-degree intervals on the circumferential direction of the outer wall of the first tubular body 130. A first tubular body 130 is inserted into a cylindrical sleeve 110, the two ends of which are locked by nuts 120 and spacers, thereby airtightly fixing the first tubular body 130 to the sleeve 110. A pipe 4 connected to a water valve is connected to the first tubular body 130 via a liquid inlet 20, which serves as an adapter. Additionally, a pipe 5 connected to the compressor 8 is connected to a gas inlet formed in the sleeve 110. A pipe 6 connected to the shower head is connected to a second tubular body 150.

[0124] In the examples and comparative examples, the gas-liquid mixture was measured five times. The results are shown in Table 1.

[0125] [Table 1]

[0126] As shown in Table 1, it can be seen that by using the microbubble generator 1 described in the embodiments, a gas-liquid mixture containing a large number of nanoscale (bubble diameter less than 1 μm) microbubbles can be obtained. Specifically, in the gas-liquid mixture obtained by the microbubble generator 1 of the embodiments, the average particle size of the bubbles is 114.2 nm, the standard deviation (SD) of the measured bubble particle size is 39.0, and these microbubbles have an average size of 7.14 × 10⁻⁶ per mL. 7 The concentration of particles was considered. Furthermore, in the examples, 90% of the bubbles in the gas-liquid mixture were 167.0 nm or smaller. In contrast, in the gas-liquid mixture obtained in the comparative example, the average bubble size was 120.9 nm, and the standard deviation (SD) of the measured bubble size was 39.0. These fine bubbles had an average size of 3.22 × 10⁻⁶ per mL. 7 The particle concentration is used to determine the inclusion. Additionally, in the comparative example, 90% of the bubbles in the gas-liquid mixture were below 185.1 nm.

[0127] Therefore, it can be seen that the microbubble generator 1 of the embodiment contains finer microbubbles and a higher concentration of microbubbles in the obtained gas-liquid mixture compared to the comparative example. Furthermore, compared to the total length H100 of the microbubble generator 101 of the comparative example (20.6 cm), the total length H0 of the microbubble generator 1 of the embodiment is 55 mm. Although this represents a reduction of less than 30% compared to the conventional design, it can still withstand the pressure of air G and water M under the same conditions. Additionally, it can be confirmed that the microbubble generator 1 of the embodiment has fewer components and fewer manufacturing steps compared to the microbubble generator 101 of the comparative example.

[0128] Industrial availability The microbubble generator of the present invention is used to produce a gas-liquid mixture containing microbubbles, and can be appropriately used in the fields of beauty and health, agriculture, etc.

[0129] Explanation of reference numerals in the attached figures 1. Microbubble generator 2. Bubble Generator 10 manifold 10a Internal 10b pipe wall 11a Inner surface 11a0 Stop surface 11a1 Main body inner surface 11a2 Positioning Surface 11a3 Inner surface of the outlet section 11b Outer surface 11b1 First Page 11b2 Second page 11b3 Third page 11b4 Fourth page 11b5 Fifth page 11b6, Page 6 11c1 First end face 11c2 Second end face 11c3 front end 12 Main body 14 Gas Inlet Section 15 Gas supply ports 16 thread 20 Liquid Inlet Section 21 Liquid supply port 22 thread 26 Export Section 27 Discharge outlets 28 thread 29 Generation Department 30 Downstream inner pipe 31 Pipe wall 31a Inner surface 31a1 Part 1 31a2 Part Two 31a3 Part Three 31b Outer surface 32 Downstream connection 33 End face 34 Downstream side narrowing section 35 Downstream end 36. Front end 37 Front outer surface 38 Stepped surface 39 End face 50 Upstream side inner pipe 51 Pipe wall 51a Inner Surface 51a1 Part 1 51a2 Part Two 51a3 Part Three 51a4 Part Four 51b outer surface 52 Upstream end 53 End face 54. Upstream side narrowing section 55. Expanded Diameter Section 56 Through holes 57. Upstream connecting part 58 end face 60 Narrowing section 70 flow path 71 First flow path section 72 Second flow path section (gas-liquid mixing section) 80 gap 3 Shower head 4, 5, 6 piping 7. Liquid supply source 8. Gas supply mechanism L liquid G pressurized gas M gas-liquid mixture 101 Microbubble Generator 102 Bubble Generator 110 casing 120 nuts 130 First tubular body 150 Second tubular body Claims (as amended under Article 19 of the Treaty) 1. [Corrected] A microbubble generating device, wherein the microbubble generating device is a microbubble generating device having a bubble generator, wherein the bubble generator mixes liquid continuously supplied from a liquid supply source with gas supplied from a gas supply mechanism to generate microbubbles, and discharges the gas-liquid mixture of the microbubbles and the liquid. The bubble generator is characterized by having a manifold and tubular internal components. The manifold has a liquid inlet for supplying the liquid to its interior, a gas inlet for supplying the gas to its interior, and an outlet for generating the microbubbles and discharging the gas-liquid mixture containing the microbubbles, and is formed as a separate component. The tubular internal component is assembled and housed inside the manifold, and has a flow path inside for the liquid supplied from the liquid inlet to flow to the outlet. The internal components consist of a downstream inner tube and an upstream inner tube. The downstream inner tube is disposed downstream of the direction of liquid flow and is formed as a separate component, while the upstream inner tube is disposed upstream and is formed as a separate component. The upstream inner tube is provided with a through hole that allows the gas supplied from the gas inlet to be introduced into the flow path. The downstream inner pipe is connected to the upstream inner pipe inside the manifold. The flow path connects the upstream inner tube and the downstream inner tube in a substantially coaxial manner between the liquid inlet and the outlet. The downstream inner tube has a downstream connecting portion connected to the upstream inner tube, a downstream end connected to the interior of the outlet portion, and a downstream diameter-reducing portion that narrows the inner diameter from the downstream connecting portion toward the downstream end. The upstream inner tube has an upstream diameter reduction section that narrows its inner diameter toward the downstream side, an expansion section that widens its inner diameter from the upstream diameter reduction section toward the downstream side, and an upstream connecting section that connects to the downstream connecting section. The through hole is located in the enlarged diameter section. 2. [Delete]. 3. The microbubble generator according to claim 1, characterized in that the minimum inner diameter of the downstream inner tube is smaller than the minimum inner diameter of the upstream inner tube. The outlet portion has a portion that is at least larger than the minimum inner diameter of the downstream inner tube. 4. [After correction] The microbubble generating device according to claim 1, wherein the downstream end is fitted and connected to the outlet part. 5. [After correction] The microbubble generating device according to claim 1, characterized in that the central axis of the flow path in the downstream diameter reduction section and the central axis of the flow path in the upstream diameter reduction section are arranged coaxially. 6. [After correction] The microbubble generating device according to claim 1, wherein the downstream connecting part is connected to the upstream connecting part in such a way that the inner surface of the downstream connecting part is substantially the same as the inner surface of the upstream connecting part. 7. [After correction] The microbubble generating device according to claim 1, characterized in that the downstream connecting part and the upstream connecting part are connected at the end face of the flow path that is substantially perpendicular to the central axis of the upstream side narrowing part. 8. [After correction] The microbubble generating device according to claim 1, wherein the through hole is inclined relative to the central axis of the flow path in the upstream constriction section and penetrates the pipe wall of the expansion section. 9. [After correction] The microbubble generating device according to claim 1, wherein the through holes are multiple and are evenly arranged in the circumferential direction of the enlarged diameter portion. 10. [Corrected] The microbubble generator according to claim 1, characterized in that a gap is formed between the outer surfaces of the upstream constricted portion and the expanded portion and the inner surface of the manifold. Each of the through holes extends from the gap to the flow path. 11. The microbubble generator according to claim 1, characterized in that the liquid inlet, the gas inlet, and the outlet are respectively formed with threads for threaded connection with other pipes. 12. [Corrected] A method for manufacturing a microbubble generator, wherein the microbubble generator mixes a liquid continuously supplied from a liquid supply source with a gas supplied from a gas supply mechanism to generate microbubbles, and discharges a gas-liquid mixture of the microbubbles and the liquid. The manufacturing method is characterized by comprising: The manifold forming process involves forming the manifold as an independent component, wherein the manifold has a liquid inlet for supplying liquid to the interior, a gas inlet for supplying gas to the interior, and an outlet for generating microbubbles and exporting the gas-liquid mixture containing the microbubbles. The downstream inner tube forming process is a process in which the downstream inner tube is formed as an independent component, and the downstream inner tube is disposed on the downstream side in the direction of liquid flow. The upstream inner tube forming process involves forming the upstream inner tube as a separate component. The upstream inner tube is positioned upstream of the liquid flow direction and has a through-hole for introducing gas supplied from the gas inlet. An assembly process in which the downstream inner tube and the upstream inner tube communicating with the downstream inner tube are assembled and housed inside the formed manifold in the following manner: the formed upstream inner tube and the formed downstream inner tube are coaxially arranged to form a flow path for allowing liquid supplied from the liquid inlet to flow to the outlet. The downstream inner tube forming process includes the process of forming a downstream inner tube, the downstream inner tube having a downstream connecting portion connected to the upstream inner tube, a downstream end connected to the interior of the outlet portion, and a downstream diameter reduction portion that reduces the inner diameter from the downstream connecting portion toward the downstream end. The upstream inner tube forming process includes forming an upstream inner tube and arranging the through hole in the enlarged diameter section. The upstream inner tube has an upstream diameter reduction section that reduces the inner diameter toward the downstream side, an enlarged diameter section that expands the inner diameter from the upstream diameter reduction section toward the downstream side, and an upstream connecting section that is connected to the downstream connecting section. 13. [Deleted]. 14. [After correction] The method for manufacturing a microbubble generator according to claim 12, characterized in that, The downstream inner tube forming process or the upstream inner tube forming process includes a process of forming such that the minimum inner diameter of the downstream inner tube is smaller than the minimum inner diameter of the upstream inner tube. The manifold forming process includes a process of forming a portion such that the outlet portion has a diameter at least larger than the minimum inner diameter of the downstream inner tube. 15. [After correction] The method for manufacturing a microbubble generating device according to claim 12, characterized in that the assembly process includes a process in which the downstream end of the downstream inner tube is fitted and connected to the outlet portion of the manifold. 16. [Corrected] The method for manufacturing a microbubble generating device according to claim 12, characterized in that the assembly process includes a process in which the central axis of the flow path in the downstream diameter reduction section of the downstream inner tube and the central axis of the flow path in the upstream diameter reduction section of the upstream inner tube are arranged coaxially. 17. [Corrected] The method for manufacturing a microbubble generating device according to claim 12, characterized in that the assembly process includes a process of connecting the downstream connecting portion of the downstream inner tube to the upstream connecting portion in such a manner that the inner surface of the downstream connecting portion of the downstream inner tube is substantially the same as the inner surface of the upstream connecting portion of the upstream inner tube. 18. [Corrected] The method for manufacturing a microbubble generating device according to claim 12, characterized in that the assembly process includes a process in which the downstream connecting portion of the downstream inner tube and the upstream connecting portion of the upstream inner tube are connected to each other by an end face that is substantially perpendicular to the central axis of the flow path in the upstream diameter reduction portion of the upstream inner tube. 19. [Corrected] The method for manufacturing a microbubble generating device according to claim 12, characterized in that the upstream inner tube forming step includes a step of forming the upstream inner tube by means of the through hole being inclined relative to the central axis of the flow path in the upstream reduced diameter section and penetrating the tube wall of the expanded diameter section. 20. [Corrected] The method for manufacturing a microbubble generating device according to claim 12, characterized in that the upstream inner tube forming process includes the process of forming a plurality of through holes evenly arranged in the circumferential direction of the enlarged diameter portion. 21. [Corrected] The method for manufacturing a microbubble generating device according to claim 12, characterized in that the assembly step includes a step of assembling the device in such a way that a gap is formed between the outer surfaces of the upstream-side reduced diameter portion and the expanded diameter portion of the upstream-side inner tube and the inner surface of the manifold, thereby extending the plurality of through holes from the gap to the flow path. 22. [Corrected] The method for manufacturing a microbubble generator according to claim 12 is characterized in that the manifold forming process includes forming threads for threaded connection with other pipes in the liquid inlet, the gas inlet and the outlet respectively.

Claims

1. A microbubble generating device, wherein the microbubble generating device is a microbubble generating device having a bubble generator, wherein the bubble generator mixes liquid continuously supplied from a liquid supply source with gas supplied from a gas supply mechanism to generate microbubbles, and discharges the gas-liquid mixture of the microbubbles and the liquid. Its features are, The bubble generator has a manifold and tubular internal components. The manifold has a liquid inlet for supplying the liquid to its interior, a gas inlet for supplying the gas to its interior, and an outlet for generating the microbubbles and discharging the gas-liquid mixture containing the microbubbles, and is formed as a separate component. The tubular internal component is assembled and housed inside the manifold, and has a flow path inside for the liquid supplied from the liquid inlet to flow to the outlet. The internal components consist of a downstream inner tube and an upstream inner tube. The downstream inner tube is disposed downstream of the direction of liquid flow and is formed as a separate component, while the upstream inner tube is disposed upstream and is formed as a separate component. The upstream inner tube is provided with a through hole that allows the gas supplied from the gas inlet to be introduced into the flow path. The downstream inner pipe is connected to the upstream inner pipe inside the manifold. The flow path connects the upstream inner tube and the downstream inner tube in a substantially coaxial manner between the liquid inlet and the outlet.

2. The microbubble generator according to claim 1, characterized in that, The downstream inner tube has a downstream connecting portion connected to the upstream inner tube, a downstream end connected to the interior of the outlet portion, and a downstream diameter-reducing portion that narrows the inner diameter from the downstream connecting portion toward the downstream end. The upstream inner tube has an upstream diameter reduction section that narrows its inner diameter toward the downstream side, an expansion section that widens its inner diameter from the upstream diameter reduction section toward the downstream side, and an upstream connecting section that connects to the downstream connecting section. The through hole is located in the enlarged diameter section.

3. The microbubble generator according to claim 1, characterized in that, The minimum inner diameter of the downstream inner tube is smaller than the minimum inner diameter of the upstream inner tube. The outlet portion has a portion that is at least larger than the minimum inner diameter of the downstream inner tube.

4. The microbubble generator according to claim 2, characterized in that, The downstream end is fitted into and connected to the outlet portion.

5. The microbubble generator according to claim 2, characterized in that, The central axis of the flow path in the downstream diameter reduction section is coaxial with the central axis of the flow path in the upstream diameter reduction section.

6. The microbubble generator according to claim 2, characterized in that, The downstream connecting portion is connected to the upstream connecting portion in such a way that its inner surface is substantially the same as the inner surface of the upstream connecting portion.

7. The microbubble generator according to claim 2, characterized in that, The downstream connection and the upstream connection are connected at an end face that is substantially perpendicular to the central axis of the flow path in the upstream narrowing section.

8. The microbubble generator according to claim 2, characterized in that, The through hole is inclined relative to the central axis of the flow path in the upstream diameter reduction section and penetrates the pipe wall of the diameter expansion section.

9. The microbubble generator according to claim 2, characterized in that, The through holes are multiple and are evenly arranged circumferentially in the enlarged diameter section.

10. The microbubble generator according to claim 2, characterized in that, A gap is formed between the outer surfaces of the upstream constricted section and the constricted section and the inner surface of the manifold. Each of the through holes extends from the gap to the flow path.

11. The microbubble generator according to claim 1, characterized in that, The liquid inlet, the gas inlet, and the outlet are each formed with threads for connection to other piping threads.

12. A method for manufacturing a microbubble generator, wherein the microbubble generator mixes a liquid continuously supplied from a liquid supply source with a gas supplied from a gas supply mechanism to generate microbubbles, and discharges a gas-liquid mixture of the microbubbles and the liquid. Its features are, The manufacturing method comprises: The manifold forming process involves forming the manifold as an independent component, wherein the manifold has a liquid inlet for supplying liquid to the interior, a gas inlet for supplying gas to the interior, and an outlet for generating microbubbles and exporting the gas-liquid mixture containing the microbubbles. The downstream inner tube forming process is a process in which the downstream inner tube is formed as an independent component, and the downstream inner tube is disposed on the downstream side in the direction of liquid flow. The upstream inner tube forming process involves forming the upstream inner tube as a separate component. The upstream inner tube is positioned upstream of the liquid flow direction and has a through-hole for introducing gas supplied from the gas inlet. An assembly process in which the downstream inner tube and the upstream inner tube communicating with the downstream inner tube are assembled and housed inside the formed manifold in the following manner: the formed upstream inner tube and the formed downstream inner tube are coaxially arranged to form a flow path for allowing liquid supplied from the liquid inlet to flow to the outlet.

13. The method for manufacturing the microbubble generator according to claim 12, characterized in that, The downstream inner tube forming process includes the process of forming a downstream inner tube, the downstream inner tube having a downstream connecting portion connected to the upstream inner tube, a downstream end connected to the interior of the outlet portion, and a downstream diameter reduction portion that reduces the inner diameter from the downstream connecting portion toward the downstream end. The upstream inner tube forming process includes forming an upstream inner tube and arranging the through hole in the enlarged diameter section. The upstream inner tube has an upstream diameter reduction section that reduces the inner diameter toward the downstream side, an enlarged diameter section that expands the inner diameter from the upstream diameter reduction section toward the downstream side, and an upstream connecting section that is connected to the downstream connecting section.

14. The method for manufacturing the microbubble generator according to claim 12, characterized in that, The downstream inner tube forming process or the upstream inner tube forming process includes a process of forming such that the minimum inner diameter of the downstream inner tube is smaller than the minimum inner diameter of the upstream inner tube. The manifold forming process includes forming a portion such that the outlet portion has a diameter at least larger than the minimum inner diameter of the downstream inner tube.

15. The method for manufacturing the microbubble generator according to claim 13, characterized in that, The assembly process includes the process of fitting and connecting the downstream end of the downstream inner tube with the outlet portion of the manifold.

16. The method for manufacturing the microbubble generator according to claim 13, characterized in that, The assembly process includes arranging the central axis of the flow path in the downstream diameter reduction section of the downstream inner tube and the central axis of the flow path in the upstream diameter reduction section of the upstream inner tube on the same axis.

17. The method for manufacturing the microbubble generator according to claim 13, characterized in that, The assembly process includes connecting the downstream connecting portion of the downstream inner tube to the upstream connecting portion in such a manner that the inner surface of the downstream connecting portion of the downstream inner tube is substantially the same as the inner surface of the upstream connecting portion of the upstream inner tube.

18. The method for manufacturing the microbubble generator according to claim 13, characterized in that, The assembly process includes connecting the downstream connecting portion of the downstream inner tube and the upstream connecting portion of the upstream inner tube to each other via an end face that is substantially perpendicular to the central axis of the flow path in the upstream diameter reduction portion of the upstream inner tube.

19. The method for manufacturing the microbubble generator according to claim 13, characterized in that, The upstream inner tube forming process includes forming the upstream inner tube by means of the through hole being inclined relative to the central axis of the flow path in the upstream reduced diameter section and penetrating the tube wall of the expanded diameter section.

20. The method for manufacturing the microbubble generator according to claim 13, characterized in that, The upstream inner tube forming process includes the process of forming a plurality of through holes that are evenly arranged circumferentially in the enlarged diameter section.

21. The method for manufacturing the microbubble generator according to claim 13, characterized in that, The assembly process includes assembling the tube in such a way that a gap is formed between the outer surfaces of the upstream-side reduced diameter portion and the expanded diameter portion of the upstream inner tube and the inner surface of the manifold, thereby extending the plurality of through holes from the gap to the flow path.

22. The method for manufacturing the microbubble generator according to claim 12, characterized in that, The manifold forming process includes forming threads for connection with other piping in the liquid inlet, the gas inlet, and the outlet.

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