Microbubble generating device, water heater and dishwasher

Abstract

A microbubble generating device has an inflow portion, an outflow portion, a first microbubble generating portion provided between the inflow portion and the outflow portion, and a second microbubble generating portion provided between the first microbubble generating portion and the outflow portion. The first microbubble generating portion has a Venturi portion having a reduced-diameter flow path whose flow path diameter is reduced from upstream to downstream and an enlarged-diameter flow path whose flow path diameter is enlarged from upstream to downstream. The second microbubble generating portion has a plurality of swirl flow generating portions arranged along a downstream-side central axis direction of the second microbubble generating portion. The plurality of swirl flow generating portions each has a shaft portion extending along the downstream-side central axis direction, an outer peripheral portion surrounding the shaft portion, and a plurality of blade portions provided between the shaft portion and the outer peripheral portion, which generate a swirl flow flowing in a prescribed swirl direction with respect to the shaft portion.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a microbubble generator, a water heater, and a dishwasher. Background Technology

[0002] Japanese Patent Publication No. 2018-8193 discloses a microbubble generating device, comprising an inlet for gas-dissolved water to flow in, an outlet for gas-dissolved water to flow out, and a microbubble generating section disposed between the inlet and outlet. The microbubble generating section has a narrowing flow path and an expanding flow path, wherein the diameter of the narrowing flow path decreases from upstream to downstream; the expanding flow path is disposed downstream of the narrowing flow path, and its diameter increases from upstream to downstream. Summary of the Invention

[0003] [The technical problem that the invention aims to solve]

[0004] In the microbubble generating apparatus described in Japanese Patent Publication No. 2018-8193, water containing dissolved gas (hereinafter sometimes referred to as "gas-dissolved water") flows into the narrowed flow path of the microbubble generating section via an inlet. The gas-dissolved water experiences an increased flow velocity as it passes through the narrowed flow path, resulting in depressurization. Bubbles are generated due to the depressurization of the gas-dissolved water. Then, the gas-dissolved water is gradually pressurized as it passes through an expanding flow path. When the gas-dissolved water, after bubble generation due to depressurization, is pressurized, the bubbles contained within it break apart into microbubbles. Thus, in the microbubble generating apparatus of Japanese Patent Publication No. 2018-8193, microbubbles are generated by the microbubble generating section. However, in the microbubble generating apparatus of Japanese Patent Publication No. 2018-8193, the amount of microbubbles generated by the microbubble generating apparatus may be insufficient.

[0005] This specification provides a technique for generating microbubbles in large quantities.

[0006] [Technical solutions used to solve technical problems]

[0007] The microbubble generator disclosed in this specification includes an inlet section, an outlet section, a first microbubble generating section, and a second microbubble generating section. The inlet section receives gas-dissolved water; the outlet section receives the gas-dissolved water; the first microbubble generating section is disposed between the inlet section and the outlet section; the second microbubble generating section is disposed between the first microbubble generating section and the outlet section. The first microbubble generating section has a venturi portion with a narrowing flow path and an expanding flow path, wherein the diameter of the narrowing flow path varies from upstream to downstream. The diameter is reduced; the diameter expansion flow path is located downstream of the diameter reduction flow path, and the flow path diameter increases from upstream to downstream. The second microbubble generating section has a plurality of swirling flow generating sections arranged along the downstream central axis direction of the second microbubble generating section. The plurality of swirling flow generating sections each have a shaft section, an outer peripheral section and a plurality of blade sections. The shaft section extends along the downstream central axis direction; the outer peripheral section surrounds the shaft section; the plurality of blade sections are disposed between the shaft section and the outer peripheral section to generate a swirling flow that flows relative to the shaft section in a predetermined swirling direction.

[0008] According to the above structure, the dissolved gas water flowing into the microbubble generator flows into the first microbubble generating section. The dissolved gas water flowing into the first microbubble generating section experiences an increased flow velocity as it passes through a narrowing flow path, resulting in depressurization. Bubbles are generated due to the depressurization of the dissolved gas water. Next, the dissolved gas water is gradually pressurized as it passes through an expanding flow path. When the dissolved gas water, after bubble generation due to depressurization, is pressurized, the bubbles contained in the dissolved gas water break apart into microbubbles. Then, the dissolved gas water passing through the first microbubble generating section flows into the swirling flow generating section of the second microbubble generating section. The dissolved gas water flowing into the swirling flow generating section becomes a swirling flow flowing in a predetermined swirling direction. The microbubbles in the dissolved gas water become even finer bubbles due to the shear force generated by the swirling flow, and the number of microbubbles increases. Compared to a structure where the dissolved gas water passes through one swirling flow generating section, passing the dissolved gas water through multiple swirling flow generating sections extends the path of the dissolved gas water as a swirling flow. Therefore, the microbubbles in the dissolved gas water are made into even finer bubbles, and the number of microbubbles is increased. Thus, a large number of microbubbles can be generated.

[0009] In one or more embodiments, the direction opposite to the predetermined swirling direction is defined as the opposite swirling direction. The plurality of blades in the swirling flow generating section can be configured such that the end of a specific blade in the swirling direction is located on the opposite swirling direction side of the end of a blade adjacent to that specific blade in the swirling direction. When viewing the swirling flow generating section from the downstream central axis direction, the swirling flow generating section can be provided with a plurality of first openings. When viewing the swirling flow generating section from the downstream central axis direction, the plurality of first openings can be respectively surrounded by the end of the specific blade in the swirling direction, the end of the adjacent blade in the opposite swirling direction, the shaft portion, and the outer peripheral portion. When the second microbubble generating section is viewed from the direction of the downstream central axis, the multiple blades of the downstream swirling flow generating section, that is, the multiple swirling flow generating section that is different from the swirling flow generating section provided on the upstream side, can be configured such that, on the upstream side of the downstream swirling flow generating section, at least a portion of the corresponding first opening of the multiple first openings of the upstream swirling flow generating section adjacent to the downstream swirling flow generating section overlaps with at least a portion of the corresponding first opening of the upstream swirling flow generating section adjacent to the downstream swirling flow generating section.

[0010] According to the above structure, when viewing the second microbubble generating section from the downstream central axis direction, compared to a structure where the multiple blades of the downstream swirling flow generating section do not overlap with the corresponding first openings of the multiple first openings of the upstream swirling flow generating section, the amount of dissolved gaseous water flowing out of the upstream swirling flow generating section that does not pass through the blades of the downstream swirling flow generating section but passes through the downstream swirling flow generating section can be reduced. That is, the amount of dissolved gaseous water reaching the blades of the downstream swirling flow generating section can be increased. Therefore, the amount of dissolved gaseous water flowing as a swirling flow can be increased. Therefore, a larger quantity of microbubbles can be generated.

[0011] In one or more embodiments, when the second microbubble generating section is viewed from the downstream central axis direction, the plurality of blades of the downstream swirling flow generating section can be configured to overlap with the corresponding first opening of the plurality of first openings of the upstream swirling flow generating section.

[0012] According to the above structure, most of the dissolved water in the gas flowing out from the upstream swirling flow generating section will flow into the blade section of the downstream swirling flow generating section. Therefore, the amount of dissolved water in the gas flowing as a swirling flow can be increased. Therefore, a larger quantity of microbubbles can be generated.

[0013] In one or more embodiments, the downstream end of the swirling flow generating section may be provided with a plurality of second openings. The plurality of second openings may be surrounded by the swirling direction end of the specific blade portion, the swirling direction end of the adjacent blade portion, the shaft portion, and the outer peripheral portion, respectively. When viewing the second microbubble generating section from the downstream central axis direction, the ends of the plurality of blade portions of the downstream swirling flow generating section on the opposite swirling direction side may be located near the center portion in the swirling direction of the corresponding second opening among the plurality of second openings.

[0014] According to the above structure, a portion of the dissolved water flowing from the upstream swirling flow generating section collides with the end of the blade section of the downstream swirling flow generating section in the opposite direction of swirling. Through this collision, microbubbles within the dissolved water break down into even finer bubbles, increasing the number of microbubbles. Furthermore, a portion of the dissolved water flowing from the upstream swirling flow generating section is sheared as it passes through the end of the blade section of the downstream swirling flow generating section in the opposite direction of swirling. This shearing further breaks down the microbubbles within the dissolved water into even finer bubbles, further increasing the number of microbubbles. Therefore, a large quantity of microbubbles can be generated.

[0015] In one or more embodiments, the first microbubble generating unit may have a plurality of venturi portions. The plurality of venturi portions may include a plurality of outer venturi portions arranged around the central axis of the first microbubble generating unit, i.e., the upstream central axis. The number of the plurality of outer venturi portions may be the same as the number of the plurality of blade portions of the upstreammost swirling flow generating unit located on the upstream side of the plurality of swirling flow generating units. The downstream end of the expansion flow path of each of the plurality of outer venturi portions may face the corresponding blade portion of the plurality of blade portions of the upstreammost swirling flow generating unit.

[0016] According to the above structure, most of the dissolved water in the gas flowing out of the first microbubble generating section will flow into the blade section of the upstream swirling flow generating section. Therefore, the amount of dissolved water in the gas flowing as a swirling flow can be increased. Therefore, a larger quantity of microbubbles can be generated.

[0017] In one or more embodiments, the first microbubble generating unit may have a plurality of Venturi portions. The plurality of Venturi portions may include a plurality of outer Venturi portions arranged around the central axis of the first microbubble generating unit, i.e., the upstream central axis. The number of the plurality of outer Venturi portions may be the same as the number of the plurality of blade portions of the upstreammost swirling flow generating unit located on the upstream side. The downstream end of the expansion flow path of each of the plurality of outer Venturi portions may face the end of the corresponding blade portion of the upstreammost swirling flow generating unit on the opposite swirling direction side.

[0018] According to the above structure, a portion of the dissolved water gas flowing out from the first microbubble generation unit collides with the end of the blade portion of the upstream swirling flow generation unit on the opposite side of its swirling direction. Through this collision, the microbubbles within the dissolved water break down into even finer bubbles, increasing the number of microbubbles. Furthermore, a portion of the dissolved water gas flowing out from the first microbubble generation unit is sheared as it passes through the end of the blade portion of the upstream swirling flow generation unit on the opposite side of its swirling direction. This shearing further breaks down the microbubbles within the dissolved water into even finer bubbles, further increasing the number of microbubbles. Therefore, it is possible to generate a large quantity of microbubbles.

[0019] In one or more embodiments, the microbubble generating device may further include a main housing housing the first microbubble generating section and the second microbubble generating section. The main housing housing may have a first positioning section and a second positioning section, wherein the first positioning section is used to position the first microbubble generating section and the main housing housing; and the second positioning section is used to position the second microbubble generating section and the main housing housing.

[0020] According to the above structure, by positioning the first microbubble generating part and the main body shell by the first positioning part, and positioning the second microbubble generating part and the main body shell by the second positioning part, the multiple outer Venturi portions of the first microbubble generating part and the multiple blade portions of the upstream swirling flow generating part of the second microbubble generating part are positioned. Therefore, most of the dissolved water in the gas flowing out of the first microbubble generating part can flow into the blade portion of the upstream swirling flow generating part, or collide with the end of the blade portion of the upstream swirling flow generating part in the opposite direction of swirling, or shear it as it passes through the end of the blade portion of the upstream swirling flow generating part in the opposite direction of swirling. Therefore, a large number of microbubbles can be generated.

[0021] In one or more embodiments, each of the plurality of swirling flow generating units may have an upstream-side protrusion protruding upstream or an upstream-side recessed portion recessed downstream at its upstream end. When the upstream-side protrusion is provided at the upstream end of the swirling flow generating unit, a downstream-side recessed portion is provided at the downstream end; conversely, when the upstream-side recess is provided at the upstream end of the swirling flow generating unit, a downstream-side protrusion protruding downstream is provided at the downstream end. The upstream-side protrusion may have a shape corresponding to the second positioning part and the downstream-side recessed portion. The upstream-side recessed portion may have a shape corresponding to the second positioning part and the downstream-side protrusion.

[0022] According to the above structure, the main body shell and the upstreammost swirling flow generating unit can be positioned using the upstream side protrusion or concave portion at the upstream end of the swirling flow generating unit, and two adjacent swirling flow generating units in the downstream central axis direction can also be positioned. In this case, it is not necessary to provide a different structure from the upstream side protrusion or concave portion in order to position the main body shell and the upstreammost swirling flow generating unit at the upstream end of the upstreammost swirling flow generating unit. Therefore, the structure of multiple swirling flow generating units can be common.

[0023] In one or more embodiments, the plurality of venturi portions may further include an inner venturi portion extending along the upstream central axis. The downstream end of the expansion flow path of the inner venturi portion may face the axis of the upstreammost swirling flow generating portion. The opening area of ​​the downstream end of the expansion flow path of the inner venturi portion may be smaller than the area of ​​the axis of the upstreammost swirling flow generating portion when viewed from the downstream central axis direction.

[0024] According to the above structure, compared to a structure where the opening area at the downstream end of the expanded flow path in the inner venturi section is larger than the area of ​​the shaft portion of the upstream swirling flow generating section, most of the dissolved gas water flowing out from the inner venturi section can collide with the shaft portion of the upstream swirling flow generating section. Through this collision between the dissolved gas water and the shaft portion, the microbubbles within the dissolved gas water break down into even finer bubbles, increasing the quantity of microbubbles. Therefore, a large number of microbubbles can be generated further.

[0025] In one or more embodiments, the opening area may be smaller than the area of ​​the upstream end of the shaft portion of the upstream swirling flow generating portion when viewed from the downstream central axis direction.

[0026] A portion of the dissolved water gas flowing out from the inner venturi section can flow towards the outer side of the shaft of the upstream swirling flow generating section. According to this structure, the amount of dissolved water gas colliding with the shaft (specifically, the upstream end) of the upstream swirling flow generating section can be increased. Therefore, a larger quantity of microbubbles can be generated.

[0027] In one or more embodiments, the upstream end of the shaft portion of the upstreammost swirling flow generating portion may be provided with a recess that is recessed towards the downstream side.

[0028] According to the above structure, the dissolved water gas flowing out from the inner venturi collides with the concave portion. Then, the dissolved water gas that collided with the concave portion flows towards the inner venturi collides. In this case, the dissolved water gas flowing out from the inner venturi collides with the dissolved water gas that has flowed towards the inner venturi collides due to the collision with the concave portion. Through the collision of the dissolved water gas with each other, the microbubbles within the dissolved water gas break into even finer bubbles, and the amount of microbubbles increases. Therefore, it is possible to generate a large number of microbubbles.

[0029] In one or more embodiments, the upstream side surface of the plurality of blade portions may be provided with a protrusion that protrudes upstream.

[0030] According to the above structure, the dissolved water flowing on multiple blade sections collides with the protrusions. Through this collision, the microbubbles within the dissolved water break down into even finer bubbles, increasing the quantity of microbubbles. Therefore, it is possible to generate a large number of microbubbles.

[0031] In one or more embodiments, the downstream end of the expansion flow path of each of the plurality of outer venturi portions may face the protrusion provided on the corresponding blade portion of the plurality of blade portions of the upstream swirling flow generating portion.

[0032] Based on the above structure, the dissolved water from the gas flowing out of the outer venturi portion can reliably collide with the protrusion. Therefore, it is possible to generate a large number of microbubbles.

[0033] In one or more embodiments, the microbubble generating device may have a rectifier disposed between the second microbubble generating section and the outflow section, which rectifies the flow of gas-dissolved water from the second microbubble generating section from a swirling flow to a straight flow.

[0034] The flow of dissolved gas from the second microbubble generation unit is a swirling flow (i.e., turbulent flow). When the dissolved gas flows in a swirling flow, it is more likely to collide with the wall (hereinafter referred to as "wall") that defines the flow path downstream of the rectifier, compared to a straight flow (i.e., laminar flow). Therefore, when the flow of dissolved gas from the second microbubble generation unit is not rectified from a swirling flow to a straight flow, a relatively large amount of dissolved gas collides with the wall. In this case, the pressure loss within the microbubble generator increases, and the amount of dissolved gas flowing within the microbubble generator decreases. According to the above structure, by having the dissolved gas from the second microbubble generation unit pass through the rectifier, the flow of dissolved gas is rectified from a swirling flow (i.e., turbulent flow) to a straight flow (i.e., laminar flow). Therefore, the amount of dissolved gas colliding with the wall can be reduced, thereby reducing the pressure loss within the microbubble generator. Therefore, it is possible to increase the amount of water dissolved in the gas flowing in the microbubble generator.

[0035] In addition, this specification discloses a water heater having the above-mentioned microbubble generating device.

[0036] According to the above structure, gas-dissolved water passing through the microbubble generator is supplied to the hot water supply unit. That is, gas-dissolved water containing a large number of microbubbles can be supplied to the hot water supply unit. Because the gas-dissolved water contains a large number of microbubbles, the cleaning power when washing the user's body is improved. Therefore, the convenience for users of the water heater can be improved.

[0037] In addition, this specification discloses a dishwasher having the above-described microbubble generating device.

[0038] According to the above structure, gas-dissolved water passing through the microbubble generator is supplied to the dishwasher's washing tank. That is, gas-dissolved water containing a large number of microbubbles can be supplied to the washing tank. Because the gas-dissolved water contains a large number of microbubbles, the cleaning power when washing dishes is improved. Therefore, the convenience for users of the dishwasher can be increased. Attached Figure Description

[0039] Figure 1 This is a perspective view of the microbubble generating device 2 according to the first embodiment.

[0040] Figure 2 This is a cross-sectional view of the microbubble generating device 2 according to the first embodiment.

[0041] Figure 3 This is a perspective view of the microbubble generator 2 according to the first embodiment after the main housing 10 has been removed.

[0042] Figure 4This is a view of the first microbubble generation unit 20 in the first embodiment from the upstream side.

[0043] Figure 5 This is a diagram showing the first microbubble generation unit 20 of the first embodiment viewed from the downstream side.

[0044] Figure 6 This is a diagram showing the swirling flow generation section 50 of the second microbubble generation section 22 as described in the first embodiment, viewed from the upstream side.

[0045] Figure 7 This is a perspective view of the swirling flow generation section 50 of the second microbubble generation section 22 involved in the first embodiment, viewed from the upstream side.

[0046] Figure 8 yes Figure 2 Sectional view of VIII-VIII.

[0047] Figure 9 This is a view of the second microbubble generation unit 22 in the first embodiment from the upstream side.

[0048] Figure 10 This is a cross-sectional view of the microbubble generating device 2 according to the second embodiment.

[0049] Figure 11 This is a cross-sectional view of the microbubble generating device 2 according to the third embodiment.

[0050] Figure 12 This is a diagram showing the swirling flow generation section 350 of the second microbubble generation section 22 as described in the fourth embodiment, viewed from the upstream side.

[0051] Figure 13 This is a cross-sectional view of the microbubble generating device 2 according to the fourth embodiment.

[0052] Figure 14 This is a perspective view of the swirling flow generation section 350 of the second microbubble generation section 22 involved in the fourth embodiment, viewed from the downstream side.

[0053] Figure 15 This is a diagram showing the swirling flow generation section 350 of the second microbubble generation section 22 as described in the fourth embodiment, viewed from the downstream side.

[0054] Figure 16 yes Figure 13 Sectional view of XIV-XIV.

[0055] Figure 17 This is a diagram showing the second microbubble generation unit 22 as described in the fourth embodiment from the upstream side.

[0056] Figure 18 yes Figure 13Sectional view of XVIII-XVIII.

[0057] Figure 19 This is a diagram schematically showing the structure of the hot water system 402 according to the first embodiment.

[0058] Figure 20 This is a schematic diagram showing the structure of the dishwasher 510 according to the second embodiment.

[0059] Figure 21 This is a cross-sectional view of the microbubble generating device 2 according to the fifth embodiment.

[0060] Figure 22 This is a view of the main housing 610 involved in the fifth embodiment from the upstream side.

[0061] Figure 23 This is a perspective view of the first microbubble generation unit 620 in the fifth embodiment as viewed from the downstream side.

[0062] Figure 24 This is a perspective view of the swirling flow generation section 650 of the second microbubble generation section 622 involved in the fifth embodiment, viewed from the upstream side.

[0063] Figure 25 This is a perspective view of the swirling flow generation section 650 of the second microbubble generation section 622 involved in the fifth embodiment, viewed from the downstream side.

[0064] Figure 26 yes Figure 21 XXVI-XXVI sectional views.

[0065] Figure 27 This is a perspective view of the second microbubble generation unit 622 in the fifth embodiment as viewed from the upstream side.

[0066] Figure 28 This is a cross-sectional view of the microbubble generating device 2 according to the sixth embodiment.

[0067] Figure 29 This is a perspective view of the rectifier 770 involved in the sixth embodiment, viewed from the upstream side.

[0068] Figure 30 This is a cross-sectional view of the microbubble generating device 2 according to the 7th embodiment. Detailed Implementation

[0069] (First Embodiment)

[0070] like Figure 1As shown, the microbubble generator 2 has a main housing 10, an inlet 12, and an outlet 14. The main housing 10 has a generally cylindrical shape. The inlet 12 is screwed to the upstream end 10a of the main housing 10. An inlet 12a is formed on the inlet 12. The outlet 14 is screwed to the downstream end 10b of the main housing 10. An outlet 14a is formed on the outlet 14. Hereinafter, the central axis A of the microbubble generator 2 will sometimes be abbreviated as "central axis A".

[0071] like Figure 2 As shown, a first microbubble generating unit 20 and a second microbubble generating unit 22 disposed downstream of the first microbubble generating unit 20 are housed in the main body housing 10. The first microbubble generating unit 20 and the second microbubble generating unit 22 are disposed along the central axis A.

[0072] (Structure of the first microbubble generation section 20;) Figures 2-5 )

[0073] like Figure 3 As shown, the first microbubble generating unit 20 has a first main body 30 and a second main body 32 disposed downstream of the first main body 30. The outer diameter of the first main body 30 decreases as it moves downstream. The outer diameter of the second main body 32 increases as it moves downstream. The central axis of the first microbubble generating unit 20 is aligned with the central axis A.

[0074] like Figure 4 As shown, the first microbubble generating section 20 includes an inner venturi portion 34 and six outer venturi portions 36. The inner venturi portion 34 is located at the center of the first microbubble generating section 20. The inner venturi portion 34 is positioned on the central axis A. Figure 2 As shown, the inner venturi portion 34 has a narrowing flow path 38 and an expanding flow path 40. The diameter of the narrowing flow path 38 decreases from upstream to downstream. The expanding flow path 40 is located downstream of the narrowing flow path 38, and its diameter increases from upstream to downstream. The narrowing flow path 38 is located in the first main body portion 30. The diameter of the upstream end of the narrowing flow path 38 is smaller than the diameter of the inlet 12a of the inflow portion 12. The expanding flow path 40 is located in the second main body portion 32.

[0075] like Figure 4 As shown, six outer venturi portions 36 are arranged radially outward from the inner venturi portion 34 relative to the central axis A. The six outer venturi portions 36 are equally spaced along the circumferential direction of the central axis A. Similar to the inner venturi portion 34, each of the six outer venturi portions 36 has a narrowing flow path 38 and a widening flow path 40 (see reference). Figure 5 ).like Figure 2As shown, the upstream flow path 42 within the first microbubble generating section 20 is defined by the narrowing flow path 38 and the widening flow path 40. Water flowing into the first microbubble generating section 20 from the inlet 12 flows into the second microbubble generating section 22 via the upstream flow path 42.

[0076] (Structure of the second microbubble generation section 22;) Figure 2 , Figures 6-9 )

[0077] like Figure 2 As shown, the second microbubble generating unit 22 has four swirling flow generating units 50. The four swirling flow generating units 50 are arranged along the central axis A. The central axis of the second microbubble generating unit 22 is aligned with the central axis A. Furthermore, the terms "clockwise direction" and "counterclockwise direction" as described below refer to the direction when viewing the microbubble generating device 2 from the upstream side along the central axis A.

[0078] like Figure 6 As shown, the swirling flow generating unit 50 includes: a shaft portion 52; an outer peripheral portion 54 surrounding the shaft portion 52; and a six-blade portion 56 disposed between the shaft portion 52 and the outer peripheral portion 54, generating a swirling flow that flows clockwise relative to the shaft portion 52. The shaft portion 52 has a cylindrical shape. The outer peripheral portion 54 has a cylindrical shape. Figure 2 As shown, the outer diameter of the outer peripheral portion 54 is the same as the inner diameter of the main body housing 10. The shaft portion 52 and the outer peripheral portion 54 are arranged along the central axis A. Therefore, the central axis of the shaft portion 52 and the central axis of the outer peripheral portion 54 coincide with the central axis of the second microbubble generating section 22. Figure 6 As shown, the blade portion 56 connects the outer wall of the shaft portion 52 to the inner wall of the outer peripheral portion 54. (As...) Figure 7 As shown, the blade portion 56 is inclined downstream in a clockwise direction. A protrusion 58 protruding upstream is provided on the upstream side surface of the blade portion 56. When the swirling flow generating portion 50 is viewed from the central axis A direction, the protrusion 58 has a hexagonal cross-sectional shape. Furthermore, in modified examples, the cross-sectional shape of the protrusion 58 can be circular, fan-shaped, triangular, teardrop-shaped, etc. The blade portion 56 has an outflow end 60 on the clockwise side and an inflow end 62 on the counterclockwise side. Figure 6 As shown, when viewing the swirling flow generating section 50 from the direction of the central axis A, six first openings 64 are provided on the swirling flow generating section 50. Figure 6(The thicker part). The six first openings 64 are respectively surrounded by the outflow end 60 of one of the six blade portions 56, the inflow end 62 of the blade portion 56 adjacent to that blade portion 56 in the clockwise direction, the shaft portion 52, and the outer peripheral portion 54. In the following, the four swirling flow generating portions 50 are sometimes referred to as "first swirling flow generating portion 50", "second swirling flow generating portion 50", "third swirling flow generating portion 50", and "fourth swirling flow generating portion 50" in the order arranged from the upstream side to the downstream side. In addition, in Figure 3 For ease of observation, the reference numerals representing the shaft portion 52, outer peripheral portion 54, and blade portion 56 of the second to fourth swirling flow generating portions 50 have been omitted.

[0079] like Figure 8 As shown, the first swirling flow generating section 50 (i.e., the upstream swirling flow generating section 50) is configured such that the downstream ends of the expansion flow paths 40 of each of the six outer Venturi portions 36 of the first microbubble generating section 20 are located facing the protrusions 58 provided on the corresponding blade portions 56 of the six blade portions 56 of the first swirling flow generating section 50. Furthermore, the first swirling flow generating section 50 is configured such that the downstream ends of the expansion flow paths 40 of the inner Venturi portion 34 are located facing the shaft portion 52 of the first swirling flow generating section 50. The opening area of ​​the downstream end of the expansion flow path 40 of the inner Venturi portion 34 is smaller than the area of ​​the outer shape of the upstream end 52a of the shaft portion 52 of the first swirling flow generating section 50 when viewed from the central axis A direction.

[0080] Reference Figure 9 This explains the relationship between two adjacent swirling flow generating units 50 along the central axis A. Figure 9 The image shows a first swirling flow generating section 50 and a second swirling flow generating section 50 located downstream of the first swirling flow generating section 50. Figure 9 In the diagram, for ease of understanding, the six blades 56 of the second swirling flow generating section 50 are represented in gray. The first opening 64 is surrounded by a thick line. The second swirling flow generating section 50 is configured such that, when viewed from the central axis A, the six blades 56 of the second swirling flow generating section 50 completely overlap with the corresponding first opening 64 of the six first openings 64 of the first swirling flow generating section 50. That is, the four swirling flow generating sections 50 are configured such that, when viewed from the central axis A, the six blades 56 of the downstream swirling flow generating section 50 of two adjacent swirling flow generating sections 50 in the central axis A direction completely overlap with the corresponding blades 56 of the six first openings 64 of the upstream swirling flow generating section 50.

[0081] Next, the microbubbles generated by the microbubble generator 2 will be explained. The microbubble generator 2 generates microbubbles using water in which air is dissolved (hereinafter referred to as "air-dissolved water"). The air-dissolved water can be water supplied by a water source such as a water pipe (so-called tap water), or it can be water generated by an air-dissolved water generator that dissolves air obtained from the outside in water. Furthermore, in a modified example, in addition to air, gases such as carbon dioxide, hydrogen, and oxygen can be dissolved in the water.

[0082] like Figure 2 As shown, the air-dissolved water flowing into the microbubble generator 2 flows into the upstream flow path 42 within the first microbubble generating unit 20 via the inlet 12a of the inlet section 12. The air-dissolved water flowing into the upstream flow path 42 then flows into the inner venturi section 34 and the outer venturi section 36. The air-dissolved water flowing into the inner venturi section 34 flows into the narrowing flow path 38. The air-dissolved water flowing into the narrowing flow path 38 experiences an increased flow velocity as it passes through the narrowing flow path 38, resulting in decompression. Bubbles are generated due to the decompression of the air-dissolved water. The air-dissolved water passing through the narrowing flow path 38 flows into the expanding flow path 40. The air-dissolved water flowing into the expanding flow path 40 experiences a decreased flow velocity as it passes through the expanding flow path 40, resulting in pressurization. When the air-dissolved water, after bubble generation due to decompression, is pressurized, the bubbles contained in the air-dissolved water break apart into microbubbles. The water passing through the expanding flow path 40 flows into the second microbubble generating unit 22. In this way, microbubbles are generated by air-dissolved water passing through the inner venturi section 34. Similarly, air-dissolved water passing through the outer venturi section 36 also generates microbubbles. Air-dissolved water flowing through the upstream flow path 42 within the first microbubble generation section 20 flows into the second microbubble generation section 22.

[0083] The dissolved water from the air flowing out of the first microbubble generating section 20 will flow into the first swirling flow generating section 50 at the upstream side of the second microbubble generating section 22. For example... Figure 8As shown, dissolved air flowing from the inner Venturi portion 34 of the first microbubble generating section 20 collides with the upstream end 52a of the shaft portion 52 of the first swirling flow generating section 50. The collision of the dissolved air with the upstream end 52a causes the microbubbles within the dissolved air to break into even finer bubbles, increasing the number of microbubbles. Additionally, dissolved air flowing from the outer Venturi portion 36 of the first microbubble generating section 20 collides with the protrusion 58 of the blade portion 56 of the first swirling flow generating section 50. The collision of the dissolved air with the protrusion 58 causes the microbubbles within the dissolved air to break into even finer bubbles, increasing the number of microbubbles. After colliding with the protrusion 58, the dissolved air passes through the blade portion 56. The dissolved air, passing through the blade portion 56, becomes a swirling flow flowing clockwise. The microbubbles within the dissolved air are further amplified by the shear force generated by the swirling flow, increasing the number of microbubbles. Figure 9 As shown, dissolved air flowing from the outflow side end 60 of the blade portion 56 of the first swirling flow generating section 50 flows into the blade portion 56 of the second swirling flow generating section 50. A portion of the dissolved air flowing into the blade portion 56 of the second swirling flow generating section 50 collides with the protrusion 58 of the blade portion 56. As the dissolved air continues to flow on the blade portions 56 of both the first and second swirling flow generating sections 50, the amount of dissolved air increases due to the shearing effect of the swirling flow. Therefore, the microbubbles within the dissolved air become finer bubbles, and the amount of microbubbles increases. Then, as... Figure 2 As shown, dissolved air water passes through the third and fourth swirling flow generating units 50, which are located downstream of the second swirling flow generating unit 50. Since the dissolved air water passes through a total of four swirling flow generating units 50, the microbubbles within the dissolved air water are refined, generating a large number of microbubbles. Furthermore, the dissolved air water flowing in from the second microbubble generating unit 22 flows outward from the outlet 14a.

[0084] As mentioned above, such as Figure 2As shown, the microbubble generator 2 includes: an inlet 12 for supplying dissolved air water (an example of "dissolved gas water"); an outlet 14 for supplying dissolved air water; a first microbubble generating section 20 disposed between the inlet 12 and the outlet 14; and a second microbubble generating section 22 disposed between the first microbubble generating section 20 and the outlet 14. The first microbubble generating section 20 has an outer venturi portion 36, which includes: a narrowing flow path 38 whose diameter decreases from upstream to downstream; and an expanding flow path 40 disposed downstream of the narrowing flow path 38 whose diameter increases from upstream to downstream. The second microbubble generating unit 22 has four swirling flow generating units 50 arranged along the central axis A. Each of the four swirling flow generating units 50 has: a shaft portion 52 extending along the central axis A; an outer peripheral portion 54 surrounding the shaft portion 52; and six blade portions 56 disposed between the shaft portion 52 and the outer peripheral portion 54, generating a swirling flow that flows clockwise relative to the shaft portion 52 (an example of a "prescribed swirling direction"). According to this structure, the air-dissolved water flowing into the microbubble generating device 2 then flows into the first microbubble generating unit 20. The air-dissolved water flowing into the first microbubble generating unit 20 experiences an increased flow velocity as it passes through the narrowing flow path 38, resulting in depressurization. Bubbles are generated due to the depressurization of the air-dissolved water. Then, the air-dissolved water is gradually pressurized as it passes through the widening flow path 40. When the air-dissolved water, after bubble generation due to depressurization, is pressurized, the bubbles contained in the air-dissolved water break apart into microbubbles. Next, the air-dissolved water passing through the first microbubble generation unit 20 flows into the swirling flow generation unit 50 of the second microbubble generation unit 22. The air-dissolved water flowing into the swirling flow generation unit 50 becomes a swirling flow flowing in a clockwise direction. The microbubbles in the air-dissolved water become finer bubbles due to the shear force generated by the swirling flow, and the number of microbubbles increases. Compared to a structure where the air-dissolved water passes through one swirling flow generation unit 50, passing the air-dissolved water through four swirling flow generation units 50 extends the path of the air-dissolved water as a swirling flow. Therefore, the microbubbles in the air-dissolved water become finer bubbles, and the number of microbubbles increases. Thus, a large number of microbubbles can be generated.

[0085] In addition, such as Figure 6 As shown, the six blades 56 in the swirling flow generating section 50 are respectively configured such that the outflow end 60 (an example of the "swirling direction side end") of one of the six blades 56 is located in the counterclockwise direction (an example of the "swirling opposite direction side end") of the inflow end 62 (an example of the "swirling opposite direction side end") of the blade 56 adjacent to the other blade 56 in the clockwise direction. When the swirling flow generating section 50 is viewed from the direction of the central axis A, the swirling flow generating section 50 is provided with six first openings 64 ( Figure 6(The thicker part). When viewing the swirling flow generating section 50 from the direction of the central axis A, the six first openings 64 are respectively surrounded by the outflow side end 60 of one blade section 56, the inflow side end 62 of the adjacent blade section 56, the shaft section 52, and the outer peripheral section 54. Moreover, as Figure 9 As shown, when viewing the second microbubble generating section 22 from the direction of the central axis A, the six blades 56 of the second swirling flow generating section 50 (an example of a "downstream swirling flow generating section") are each configured to overlap at least a portion of the corresponding first opening 64 of the six first openings 64 of the first swirling flow generating section 50 (an example of an "upstream swirling flow generating section"). With this structure, compared to a structure where the six blades 56 of the second swirling flow generating section 50 do not overlap with the corresponding first openings 64 of the six first openings 64 of the first swirling flow generating section 50, the amount of dissolved air flowing from the first swirling flow generating section 50 that passes through the second swirling flow generating section 50 but not through the blades 56 can be reduced. That is, the amount of dissolved air reaching the blades 56 of the second swirling flow generating section 50 can be increased. Therefore, it is possible to increase the amount of dissolved water in the air flowing as a swirling stream. Therefore, it is possible to generate a large number of microbubbles.

[0086] In particular, in this embodiment, when viewing the second microbubble generating section 22 from the direction of the central axis A, the six blade sections 56 of the second swirling flow generating section 50 are respectively configured to completely overlap with the corresponding first opening 64 of the six first opening sections 64 of the first swirling flow generating section 50. According to the above structure, most of the air-dissolved water flowing out of the first swirling flow generating section 50 flows into the blade sections 56 of the second swirling flow generating section 50. Therefore, the amount of air-dissolved water flowing as a swirling flow can be increased. Therefore, a larger quantity of microbubbles can be generated.

[0087] In addition, such as Figure 8 As shown, the first microbubble generating unit 20 has six outer venturi portions 36 arranged around the central axis A. The number of outer venturi portions 36 (i.e., six) is the same as the number of blade portions 56 (i.e., six) of the first swirling flow generating unit 50 (an example of the "upstream swirling flow generating unit"). The downstream end of the expansion flow path 40 of each of the six outer venturi portions 36 faces the corresponding blade portion 56 of the six blade portions 56 of the first swirling flow generating unit 50. With this structure, most of the air-dissolved water flowing out of the first microbubble generating unit 20 flows into the blade portion 56 of the first swirling flow generating unit 50. Therefore, the amount of air-dissolved water flowing as a swirling flow can be increased. Therefore, a larger quantity of microbubbles can be generated.

[0088] In addition, such as Figure 8As shown, the first microbubble generating unit 20 also has an inner venturi portion 34 extending along the central axis A. The downstream end of the expanding flow path 40 of the inner venturi portion 34 faces the shaft portion 52 of the first swirling flow generating unit 50. The opening area of ​​the downstream end of the expanding flow path 40 of the inner venturi portion 34 is smaller than the area of ​​the shaft portion 52 of the first swirling flow generating unit 50 when viewed from the direction of the central axis A. According to this structure, compared with a structure in which the opening area of ​​the downstream end of the expanding flow path 40 of the inner venturi portion 34 is larger than the area of ​​the shaft portion 52 of the first swirling flow generating unit 50, most of the air-dissolved water flowing out of the inner venturi portion 34 can collide with the shaft portion 52 of the first swirling flow generating unit 50. Through the collision between the air-dissolved water and the shaft portion 52, the microbubbles in the air-dissolved water break into finer bubbles, and the amount of microbubbles increases. Therefore, it is possible to generate a large number of microbubbles. Furthermore, compared to a structure where the opening area of ​​the downstream end of the expanded flow path 40 in the inner venturi portion 34 is larger than the area of ​​the shaft portion 52 of the first swirling flow generating section 50 when viewed from the central axis A direction, the amount of air-dissolved water that passes through the first opening 64 and flows out of the first swirling flow generating section 50 without colliding with the shaft portion 52 of the first swirling flow generating section 50 can be reduced. That is, the amount of air-dissolved water that collides with the shaft portion 52 of the first swirling flow generating section 50 can be increased. Therefore, a larger quantity of microbubbles can be generated.

[0089] In addition, such as Figure 8 As shown, the opening area of ​​the downstream end of the expanding flow path 40 of the inner venturi portion 34 is smaller than the area of ​​the upstream end 52a of the shaft portion 52 of the first swirling flow generating unit 50 when viewed from the central axis A direction. A portion of the air-dissolved water flowing out from the inner venturi portion 34 can flow towards the outer direction of the shaft portion 52 of the first swirling flow generating unit 50. According to the above structure, the amount of air-dissolved water colliding with the shaft portion 52 (specifically, the upstream end 52a) of the first swirling flow generating unit 50 can be increased. Therefore, a larger quantity of microbubbles can be generated.

[0090] In addition, such as Figure 6 As shown, protrusions 58 protruding upstream are provided on the upstream side surface of the six blade sections 56. According to this structure, the air-dissolved water flowing on the six blade sections 56 collides with the protrusions 58. Through this collision, microbubbles within the air-dissolved water break down into even finer bubbles, increasing the amount of microbubbles. Therefore, a large quantity of microbubbles can be generated.

[0091] In addition, such as Figure 8As shown, the downstream end of the expansion flow path 40 of each of the six outer venturi portions 36 faces the protrusion 58 provided on the corresponding blade portion 56 of the six blade portions 56 of the first swirling flow generating section 50. With this structure, dissolved water from the air flowing out of the outer venturi portions 36 can reliably collide with the protrusion 58. Therefore, a large number of microbubbles can be generated.

[0092] (Second Embodiment)

[0093] Reference Figure 10 The microbubble generating apparatus 2 of the second embodiment will be described below. Furthermore, in the following description, the same reference numerals will be used to refer to common structures among the embodiments, and their descriptions will be omitted.

[0094] The structure of the four swirling flow generating sections 150 of the microbubble generator 2 in this embodiment is the same as that of the four swirling flow generating sections 50 in the first embodiment (see reference). Figure 2 The construction of the shaft portion 152 differs from that of the shaft portion 52 in the first embodiment (see reference 1). Figure 2 The construction differs. A recess 152b, recessed downstream, is provided at the upstream end 152a of the shaft portion 152. The recess 152b has a shape corresponding to a cylindrical shape. The diameter of the recess 152b is approximately the same as the flow path diameter at the downstream end of the inner venturi portion 34. Furthermore, in a modified example, the diameter of the recess 152b may be larger or smaller than the flow path diameter at the downstream end of the inner venturi portion 34.

[0095] As mentioned above, such as Figure 10 As shown, a recessed portion 152b is provided at the upstream end 152a of the shaft portion 152 of the first swirling flow generating section 150, extending downstream. With this structure, dissolved air flowing from the inner venturi portion 34 collides with the recessed portion 152b. Furthermore, the dissolved air that collides with the recessed portion 152b flows towards the inner venturi portion 34. In this case, dissolved air flowing from the inner venturi portion 34 collides with dissolved air that has flowed towards the inner venturi portion 34 due to colliding with the recessed portion 152b. Through this collision of dissolved air with each other, microbubbles within the dissolved air break apart into even finer bubbles, increasing the amount of microbubbles. Therefore, it is possible to generate a larger quantity of microbubbles.

[0096] (Third Embodiment)

[0097] Reference Figure 11 The microbubble generator 2 of the third embodiment will be described. The structure of the four swirling flow generating units 250 of the microbubble generator 2 of this embodiment is the same as that of the four swirling flow generating units 150 of the second embodiment (see reference). Figure 10 The construction of the shaft portion 252 differs from that of the shaft portion 252 in the second embodiment (see reference 252). Figure 10The construction differs. A recess 252b, which is recessed downstream, is provided at the upstream end 252a of the shaft portion 252. The recess 252b has a shape corresponding to a hemispherical shape. Similar to the structure of the second embodiment, with this structure, microbubbles can be generated in large quantities by the collision of dissolved air with each other. In addition, compared with the structure of the second embodiment, the retention of dissolved air passing through the recess 252b can be suppressed.

[0098] (Example 4)

[0099] Reference Figures 12-17 This section describes the microbubble generator 2 of the fourth embodiment. The structure of the four swirling flow generating sections 350 of the microbubble generator 2 of this embodiment is the same as that of the four swirling flow generating sections 50 of the first embodiment (see reference). Figure 2 The structures of ) are different.

[0100] like Figure 12 As shown, the swirling flow generating section 350 has a shaft portion 352, an outer peripheral portion 354 surrounding the shaft portion 352, and six blade portions 356. The shaft portion 352 has a cylindrical shape. The outer peripheral portion 354 has a cylindrical shape. Figure 13 As shown, the outer diameter of the outer peripheral portion 354 is the same as the inner diameter of the main body housing 10. The shaft portion 352 and the outer peripheral portion 354 are arranged along the central axis A. The blade portion 356 connects the outer wall of the shaft portion 352 to the inner wall of the outer peripheral portion 354. The blade portion 356 tilts downstream in a clockwise direction. Figure 12 As shown, the blade portion 356 has an outflow end 360 on the clockwise side and an inflow end 362 on the counterclockwise side. When viewing the swirling flow generating portion 350 from the direction of the central axis A, six first openings 363 are provided on the swirling flow generating portion 350. Figure 12 (The thicker part). The six first openings 363 are each surrounded by the outflow end 360 of one of the six blade portions 356, the inflow end 362 of the blade portion 356 adjacent to that blade portion 356 in the clockwise direction, the shaft portion 352, and the outer peripheral portion 354. Figure 14 As shown, six second openings 364 are provided at the downstream end of the swirling flow generating section 350. Figure 15 As shown in the thick lines, the six second openings 364 are respectively surrounded by the outflow end 360 of one of the six blade portions 356, the outflow end 360 of the blade portion 356 adjacent to that blade portion 356 in the clockwise direction, the shaft portion 352 and the outer peripheral portion 354.

[0101] like Figure 16As shown, the first swirling flow generating section 350 (i.e., the upstream swirling flow generating section 350) is configured such that the downstream ends of the expansion flow paths 40 of each of the six outer venturi sections 36 are located facing the inflow-side ends 362 of the corresponding blade sections 356 among the plurality of blade sections 356 of the first swirling flow generating section 350. Furthermore, the first swirling flow generating section 350 is configured such that the downstream ends of the expansion flow paths 40 of the inner venturi section 34 are located facing the shaft section 352 of the first swirling flow generating section 350. The opening area of ​​the downstream end of the expansion flow path 40 of the inner venturi section 34 is smaller than the area of ​​the outer shape of the upstream end 352a of the shaft section 352 of the first swirling flow generating section 350 when viewed from the central axis A direction.

[0102] Reference Figure 17 , Figure 18 This explains the relationship between two adjacent swirling flow generating sections 350 along the central axis A. Figure 17 , Figure 18 The first swirling flow generating unit 350 and the second swirling flow generating unit 350 are shown in the diagram. Figure 17 , 18 In the diagram, for ease of understanding, the six blade sections 356 of the second swirling flow generating section 350 are represented in gray. For example... Figure 17 As shown, the second swirling flow generating section 350 is configured such that, when viewed from the direction of the central axis A, a portion of each of the six blade portions 356 of the second swirling flow generating section 350 (specifically, a portion of the inflow-side end 362) overlaps with the corresponding first opening 363 of the six first opening portions 363 of the first swirling flow generating section 350. That is, when viewed from the direction of the central axis A, the blade portions 356 of the second swirling flow generating section 350 do not completely overlap with the blade portions 356 of the first swirling flow generating section 350. Figure 18 As shown, the second swirling flow generating section 350 is configured such that, when viewed from the direction of the central axis A, the inflow-side end 362 of each of the plurality of blade portions 356 of the second swirling flow generating section 350 is located at the plurality of second openings 364 of the first swirling flow generating section 350. Figure 18 The second swirling flow generating section 350 is located near the center of the corresponding second opening 364 in the clockwise direction in the thicker part of the first swirling flow generating section 350. In other words, when the swirling flow generating section 350 is viewed from the direction of the central axis A, the inflow-side end 362 of each of the plurality of blades 356 of the second swirling flow generating section 350 is located near the center of the clockwise direction between the outflow-side end 360 of one of the plurality of blades 356 of the first swirling flow generating section 350 and the outflow-side end 360 of the blades 356 adjacent to that one blade.

[0103] Next, the microbubbles generated by the microbubble generating apparatus 2 of this embodiment will be described. The flow of air-dissolved water passing through the first microbubble generating unit 20 is the same as in the first embodiment. Therefore, the flow of air-dissolved water passing through the second microbubble generating unit 22 of this embodiment will be described below.

[0104] like Figure 13 As shown, air-dissolved water flowing out of the first microbubble generating section 20 flows into the first swirling flow generating section 350 on the upstream side of the second microbubble generating section 22. Figure 16 As shown, dissolved air flowing from the inner venturi portion 34 of the first microbubble generating section 20 collides with the upstream end 352a of the shaft portion 352 of the first swirling flow generating section 350. This causes the microbubbles in the dissolved air to break into even finer bubbles, increasing the number of microbubbles. Additionally, dissolved air flowing from the outer venturi portion 36 of the first microbubble generating section 20 flows towards the inflow-side end 362 of the blade portion 356 of the first swirling flow generating section 350. A portion of the dissolved air flowing from the outer venturi portion 36 collides with the inflow-side end 362 of the blade portion 356 of the first swirling flow generating section 350. This causes the microbubbles in the dissolved air to break into even finer bubbles, increasing the number of microbubbles. Furthermore, when a portion of the air-dissolved water flowing out from the outer venturi portion 36 passes near the inflow-side end 362 of the blade portion 356 of the first swirling flow generating section 350, the microbubbles within the air-dissolved water are sheared. This causes the microbubbles in the air-dissolved water to become even finer bubbles, and increases the number of microbubbles. Then, a portion of the air-dissolved water passes through the blade portion 356 of the first swirling flow generating section 350. The air-dissolved water becomes a swirling flow flowing clockwise as it passes through the blade portion 356. The microbubbles within the air-dissolved water become even finer bubbles due to the shearing force generated by the swirling flow, and the number of microbubbles increases. Next, the air-dissolved water flowing out from the first swirling flow generating section 350 flows into the second swirling flow generating section 350. Figure 18As shown, a portion of the air-dissolved water flowing out from the outflow side end 360 of the blade portion 356 of the first swirling flow generating unit 350 collides with the inflow side end 362 of the blade portion 356 of the second swirling flow generating unit 350. This causes microbubbles in the air-dissolved water to break into even finer bubbles, increasing the number of microbubbles. Furthermore, when a portion of the air-dissolved water flowing out from the outflow side end 360 of the blade portion 356 of the first swirling flow generating unit 350 passes near the inflow side end 362 of the blade portion 356 of the second swirling flow generating unit 350, the microbubbles in the air-dissolved water are sheared. This causes the microbubbles in the air-dissolved water to become even finer bubbles, and increases the number of microbubbles. Then, a portion of the air-dissolved water passes through the blade portion 356 of the second swirling flow generating unit 350. Subsequently, the dissolved air water passes through the third and fourth swirling flow generating units 350, which are located downstream of the second swirling flow generating unit 350. As the dissolved air water passes through a total of four swirling flow generating units 350, the microbubbles within the dissolved air water are refined, generating a large number of microbubbles. Furthermore, as... Figure 13 As shown, the air-dissolved water flowing in from the second microbubble generation section 22 flows out to the outside from the outlet 14a.

[0105] As mentioned above, such as Figure 15 As shown, six second openings 364 are provided at the downstream end of the swirling flow generating section 350. Each of the six second openings 364 is surrounded by the outflow side end 360 of one of the six blade sections 356, the outflow side end 360 of the adjacent blade section 356, the shaft section 352, and the outer peripheral section 354. Figure 18 As shown, when viewing the second microbubble generating unit 22 from the direction of the central axis A, the inflow-side end 362 of each of the plurality of blade portions 356 of the second swirling flow generating unit 350 is located near the center of the corresponding second opening 364 in the clockwise direction among the six second opening portions 364. According to this structure, a portion of the air-dissolved water flowing out of the first swirling flow generating unit 350 collides with the inflow-side end 362 of the blade portions 356 of the second swirling flow generating unit 350. Through this collision, the microbubbles within the air-dissolved water break into even finer bubbles, increasing the amount of microbubbles. Furthermore, a portion of the air-dissolved water flowing out of the first swirling flow generating unit 350 is sheared as it passes through the inflow-side end 362 of the blade portions 356 of the second swirling flow generating unit 350. When air-dissolved water is sheared, the microbubbles within it become even smaller bubbles, increasing their quantity. Therefore, it becomes possible to generate a large number of microbubbles further.

[0106] In addition, such as Figure 16 As shown, the first microbubble generating unit 20 has six outer venturi portions 36 arranged around the central axis A. The number of outer venturi portions 36 (i.e., six) is the same as the number of blade portions 356 (i.e., six) of the first swirling flow generating unit 350 (an example of an "upstream swirling flow generating unit"). The downstream end of the expansion flow path 40 of each of the six outer venturi portions 36 faces the inflow-side end 362 of the corresponding blade portion 356 of the first swirling flow generating unit 350. According to the above structure, a portion of the air-dissolved water flowing out of the first microbubble generating unit 20 collides with the inflow-side end 362 of the blade portion 356 of the first swirling flow generating unit 350. Through the collision between the air-dissolved water and the inflow-side end 362 of the blade portion 356 of the first swirling flow generating unit 350, the microbubbles in the air-dissolved water break into finer bubbles, and the amount of microbubbles increases. Furthermore, a portion of the air-dissolved water flowing out of the first microbubble generating section 20 is sheared as it passes through the inflow-side end 362 of the blade portion 356 of the first swirling flow generating section 350. When the air-dissolved water is sheared, the microbubbles within it become even finer bubbles, increasing the quantity of microbubbles. Therefore, it is possible to generate a larger quantity of microbubbles.

[0107] Hereinafter, useful embodiments of the microbubble generating apparatus 2 of the first to fourth embodiments will be described.

[0108] (First embodiment; Structure of hot water system 402 using microbubble generator 2)

[0109] Figure 19 The hot water system 402 shown can heat water supplied from a water source 404, such as a water pipe, and supply the heated water to the desired temperature to a faucet 406 installed in the kitchen or other areas, and to a bathtub 408 installed in the bathroom. Additionally, the hot water system 402 can reheat the water in the bathtub 408.

[0110] The hot water system 402 includes a first heat source 410, a second heat source 412, and a combustion chamber 414. The first heat source 410 is used to supply hot water to the faucet 406 or to dispense hot water into the bathtub 408. The second heat source 412 is used to reheat the bathtub 408. The interior of the combustion chamber 414 is divided into a first combustion chamber 418 and a second combustion chamber 420 by a partition wall 416. The first heat source 410 is housed in the first combustion chamber 418, and the second heat source 412 is housed in the second combustion chamber 420.

[0111] The first heat source unit 410 has a first burner 422 and a first heat exchanger 424. The second heat source unit 412 has a second burner 426 and a second heat exchanger 428.

[0112] The upstream end of the first heat exchanger 424 of the first heat source unit 410 is connected to the downstream end of the water supply path 430. Water is supplied from the water source 404 to the upstream end of the water supply path 430. The downstream end of the first heat exchanger 424 is connected to the upstream end of the hot water supply path 432. The water supply path 430 and the hot water supply path 432 are connected via a bypass path 434. A bypass servo 436 is provided at the connection point between the water supply path 430 and the bypass path 434. The bypass servo 436 adjusts the ratio of the flow rate of water from the water supply path 430 to the first heat source unit 410 to the flow rate of water from the water supply path 430 to the bypass path 434. Low-temperature water via the water supply path 430 and the bypass path 434, and high-temperature water via the water supply path 430, the first heat source unit 410, and the hot water supply path 432 are mixed at the connection point between the bypass path 434 and the hot water supply path 432. A water flow sensor 438 and a water flow servo 440 are installed on the water supply path 430 upstream of the bypass servo 436. The water flow sensor 438 detects the flow rate of water flowing through the water supply path 430. The water flow servo 440 adjusts the flow rate of water flowing through the water supply path 430. A heat exchanger outlet thermistor 442 is installed upstream of the connection point between the hot water supply path 432 and the bypass path 434.

[0113] The upstream end of the hot water supply path 450 is connected to the hot water discharge path 432 downstream of the connection point of the bypass path 434. A water heater thermistor 444 is installed at the connection point of the hot water supply path 432 and the hot water discharge path 450. A microbubble generator 2 is installed between the connection point of the hot water supply path 432 and the bypass path 434 and the connection point of the hot water supply path 432 and the hot water discharge path 450. Furthermore, in the following, the water passage upstream of the microbubble generator 2 in the hot water supply path 432 is sometimes referred to as the first hot water supply path 432a, and the water passage downstream of the microbubble generator 2 in the hot water supply path 432 is sometimes referred to as the second hot water supply path 432b.

[0114] The downstream end of the hot water discharge path 450 is connected to the upstream end of the reheating path 460 and the downstream end of the first bathtub circulation path 462. The downstream end of the reheating path 460 is connected to the upstream end of the second heat exchanger 428. The upstream end of the first bathtub circulation path 462 is connected to the bathtub 408. A hot water discharge control valve 452 and a one-way valve 454 are provided on the hot water discharge path 450. The hot water discharge control valve 452 opens and closes the hot water discharge path 450. The one-way valve 454 allows water to flow from the upstream side to the downstream side of the hot water discharge path 450 and prevents water from flowing from the downstream side to the upstream side of the hot water discharge path 450. A bathtub circuit thermistor 464 is provided at the connection point of the hot water discharge path 450, the reheating path 460, and the first bathtub circulation path 462. A circulation pump 466 is provided on the reheating path 460.

[0115] The downstream end of the second heat exchanger 428 of the second heat source unit 412 is connected to the upstream end of the second bathtub circulation path 468. The downstream end of the second bathtub circulation path 468 is connected to the bathtub 408. A bathtub-out thermistor 470 is installed on the second bathtub circulation path 468.

[0116] When hot water is supplied to faucet 406 from hot water system 402, the first burner 422 of the first heat source unit 410 is ignited while the hot water control valve 452 is closed. In this case, water supplied from water source 404 to water supply path 430 is heated by heat exchange in the first heat exchanger 424 and then supplied to faucet 406 from hot water supply path 432. By adjusting the combustion rate of the first burner 422 of the first heat source unit 410 and the opening degree of bypass servo 436, the temperature of the water flowing through hot water supply path 432 can be adjusted to the desired temperature. As described above, microbubble generator 2 is provided in hot water supply path 432. Moreover, air (oxygen, carbon dioxide, nitrogen, etc.) is dissolved in the water supplied from water source 404. Therefore, the water supplied to faucet 406 from microbubble generator 2 contains a large number of microbubbles.

[0117] When hot water is released from the hot water system 402 into the bathtub 408, the first burner 422 of the first heat source unit 410 is ignited with the hot water release control valve 452 open. In this case, the water supplied from the water supply source 404 to the water supply path 430 is heated by heat exchange in the first heat exchanger 424 and flows from the hot water supply path 432 into the hot water release path 450. At this time, the water temperature is adjusted to the desired temperature by adjusting the combustion rate of the first burner 422 of the first heat source unit 410 and the opening degree of the bypass servo 436. The water flowing into the hot water release path 450 flows into the bathtub 408 via the first bathtub circulation path 462, and then into the bathtub 408 via the reheat path 460 and the second bathtub circulation path 468. Since the microbubble generator 2 is installed in the hot water supply path 432 (specifically, the first hot water supply path 432a), the water supplied to the bathtub 408 contains a large number of microbubbles.

[0118] When the hot water system 402 reheats the bathtub 408, with the hot water control valve 452 closed, the circulation pump 466 is driven to ignite the second burner 426 of the second heat source unit 412. In this situation, water from the bathtub 408 flows into the first bathtub circulation path 462 and is sent to the second heat source unit 412 via the reheating path 460. The water sent to the second heat source unit 412 is heated through heat exchange in the second heat exchanger 428 and then flows into the second bathtub circulation path 468. At this time, the water temperature is adjusted to the desired temperature by adjusting the combustion rate of the second burner 426 of the second heat source unit 412. The water flowing into the second bathtub circulation path 468 flows back into the bathtub 408.

[0119] As mentioned above, such as Figure 19 As shown, the hot water system 402 (an example of a "water heater") includes a microbubble generating device 2. With this configuration, water (an example of "gas-dissolved water") passing through the microbubble generating device 2 is supplied to the faucet 406 and the bathtub 408. That is, water containing a large number of microbubbles can be supplied to the faucet 406 and the bathtub 408. Because the water contains a large number of microbubbles, the cleaning power when washing the user's body is enhanced. Therefore, the convenience for users utilizing the hot water system 402 can be improved.

[0120] (Second embodiment; structure of dishwasher 510 utilizing microbubble generator 2)

[0121] Figure 20 This is a longitudinal sectional view of dishwasher 510. Dishwasher 510 is a pull-out dishwasher. Dishwasher 510 has a main body 512, a washing tank 514, a door 515, and a controller 560.

[0122] An operation panel 516 and an exhaust path 518 are provided on the door 515. The operation panel 516 is equipped with various buttons such as a start button and lights. The exhaust path 518 extends from the inside to the outside of the cleaning tank 514.

[0123] The cleaning tank 514 is housed within the space formed by the main body 512 and the door 515. The cleaning tank 514 is slidably supported by the main body 512. The cleaning tank 514 is connected to the door 515. The cleaning tank 514 is formed as a box shape with an open top. A cover 556 is disposed on top of the cleaning tank 514. The cover 556 is connected to the cleaning tank 514 via a lifting mechanism (not shown).

[0124] The washing tank 514 houses a washing nozzle 520, a dish basket 561 for holding various tableware 519, a leftover food filter 517, a heater 530, a thermistor 555, etc. The washing nozzle 520 consists of a tower-type nozzle section 523 and a horizontal nozzle section 524, wherein the tower-type nozzle section 523 consists of an upper nozzle 521 and a lower nozzle 522. Multiple spray nozzles 521a, 522a, and 524a are formed on the washing nozzle 520. An electric heater 530 for heating the washing water or the air inside the washing tank 514 is installed near the bottom surface 539 of the washing tank 514. A thermistor 555 is installed on the bottom surface 539 of the washing tank 514.

[0125] A water level detection unit 545 is provided on the lower part of the outer front side of the cleaning tank 514 to detect the water level inside the cleaning tank 514. The water level when cleaning water is normally supplied to the cleaning tank 514 (hereinafter referred to as "cleaning water level") is indicated by a double-dotted line of the attached drawing 554. A pump 527 is provided below the bottom surface 539 of the cleaning tank 514. The pump 527 rotates the impeller 528 by a built-in electric motor. A cleaning nozzle 520 is rotatably mounted on the bottom surface 539 of the cleaning tank 514. The cleaning nozzle 520 is connected to the first outlet 511 of the pump 527.

[0126] A suction recess 531 is formed at the bottom of the washing tank 514. The upper opening of the suction recess 531 is covered by a leftover food filter 517. A water level detection unit 545 is connected to the suction recess 531 via a water level path 550. A pump 527 is connected to the suction recess 531 via a first suction flow path 532. One end of a second suction flow path 574 is connected to the first suction flow path 532. The other end of the second suction flow path 574 is connected to an opening 572 in the rear wall 551 of the washing tank 514. A flow path switching valve 576 is installed at the connection between the first suction flow path 532 and the second suction flow path 574.

[0127] A drying fan 552 is installed on the outer side of the rear wall 551 of the cleaning tank 514. The drying fan 552 is driven by a built-in motor to rotate the fan 553. The drying fan 552 is connected to the inside of the cleaning tank 514 through a drying path 563. The drying fan 552 is configured to be higher than the cleaning water level 554.

[0128] A drain hose 534 is connected to the rear wall 533 of the main body 512. The drain hose 534 is connected to the second outlet 535 of the pump 527 through a drain path 536. The drain path 536 is connected to the cleaning tank 514 through an exhaust path 537. A drain check valve 538 is installed near the connection between the drain path 536 and the drain hose 534.

[0129] A water supply hose 540 is connected to a step formed horizontally in the middle of the rear wall 533 of the main body 512. Water from a water source such as a water supply pipe (not shown) can be directly supplied to the water supply hose 540, or heated hot water can be supplied to it. A water supply valve 541 is installed on the inner side of the rear wall 533. The inlet 544 of the water supply valve 541 is connected to the water supply hose 540 through a first water supply path 542. The outlet 564 of the water supply valve 541 is connected to the cleaning tank 514 through a second water supply path 543. A microbubble generator 2 is installed in the middle of the second water supply path 543.

[0130] The controller 560 has a CPU, ROM, RAM, etc., and controls the operation of the dishwasher 510. By controlling the operation of the dishwasher 510, the controller 560 executes the cleaning operation to clean the tableware 519 in the washing tank 514.

[0131] (Cleaning operation)

[0132] When the controller 560 receives a start operation for the dishwashing operation from the user via the control panel 516, it sequentially executes the washing process, the rinsing process, and the drying process.

[0133] During the cleaning process, the controller 560 opens the water supply valve 541, supplying cleaning water to the cleaning tank 514 from the water supply hose 540. When the controller 560 determines that the required amount of cleaning water for the cleaning process has been supplied to the cleaning tank 514, it closes the water supply valve 541. Next, the controller 560 drives the pump 527 to rotate the impeller 528 forward and activates the heater 530. Cleaning water is drawn into the pump 527 from the suction recess 531. The cleaning water drawn into the pump 527 is sent to the cleaning nozzles 520 and forcefully sprayed out from the spray ports 521a, 522a, and 524a. The controller 560 ends the cleaning process after a first predetermined time (e.g., 5 minutes) from the start of the cleaning process. Alternatively, the controller 560 drives the pump 527 to reverse the impeller 528, thereby draining the cleaning water from the cleaning tank 514. As described above, a microbubble generator 2 is installed midway through the second water supply path 543. Furthermore, air (oxygen, carbon dioxide, nitrogen, etc.) is dissolved in the water supplied from the water supply hose 540. Therefore, the water supplied to the cleaning tank 514 from the microbubble generator 2 contains a large number of microbubbles. The dirt adhering to the tableware 519 is adsorbed onto the surface of the microbubbles contained in the cleaning water. By containing a large number of microbubbles in the cleaning water, more dirt can be adsorbed.

[0134] During the rinsing process, controller 560 opens water supply valve 541, supplying rinsing water from water supply hose 540 to rinsing tank 514. When the required amount of rinsing water for the rinsing process has been supplied to rinsing tank 514, controller 560 closes water supply valve 541. Controller 560 drives pump 527 and causes impeller 528 to rotate forward. As a result, rinsing water in rinsing tank 514 is sprayed from rinsing nozzle 520 onto tableware 519 housed in cutlery basket 561, rinsing the tableware 519. Controller 560 ends the rinsing process after a second predetermined time (e.g., 5 minutes) from the start of the rinsing process. Additionally, controller 560 drives pump 527 and causes impeller 528 to rotate in reverse, thereby draining rinsing water from rinsing tank 514.

[0135] In the drying process, the controller 560 heats the air in the washing tank 514 using the heater 530 to dry the tableware 519. When the elapsed time since the start of drying of the tableware 519 reaches the third predetermined time, the controller 560 stops the heating by the heater 530 and ends the drying process.

[0136] As mentioned above, such as Figure 20 As shown, the dishwasher 510 includes a microbubble generator 2. With this configuration, cleaning water (an example of "gas-dissolved water") passing through the microbubble generator 2 is supplied to the cleaning tank 514. That is, cleaning water containing a large number of microbubbles can be supplied to the cleaning tank 514. Because the cleaning water contains a large number of microbubbles, the cleaning power when cleaning dishes 519 is improved. Therefore, the convenience for users of the dishwasher 510 can be improved.

[0137] The microbubble generating apparatus 2 according to embodiments 5 to 7 will be described below.

[0138] (5th embodiment)

[0139] Reference Figures 21-27 This section describes the microbubble generator 2 of the fifth embodiment. The structure of the main body housing 610, inflow section 612, first microbubble generating section 620, and second microbubble generating section 622 of the microbubble generator 2 of this embodiment is the same as that of the microbubble generator 2 of the fourth embodiment (see reference 4). Figure 13 )different.

[0140] like Figure 21As shown, the inner wall 612b of the downstream end of the inlet 612 expands in diameter from upstream to downstream. The diameter D1 of the downstream end of the inlet 612 is larger than the diameter D2 of the circle formed by connecting the radially outer surfaces of the six outer Venturi portions 36. With this structure, dissolved air flowing out of the inlet 612 can flow more evenly into the six outer Venturi portions 36. Furthermore, in a modified example, the diameter D1 of the downstream end of the inlet 612 may also be the same as the diameter D2 of the circle formed by connecting the radially outer surfaces of the six outer Venturi portions 36.

[0141] like Figure 22 As shown, the main body housing 610 has a first protrusion 616a to a sixth protrusion 616f that protrude radially inward from the inner wall 610c of the main body housing 610. As... Figure 21 As shown, the first protrusion 616a to the sixth protrusion 616f are arranged along the central axis A at the boundary between the first microbubble generating section 620 and the second microbubble generating section 622. Figure 22 As shown, the first protrusion 616a to the sixth protrusion 616f are arranged in a circumferential direction. The circumferential width of the first protrusion 616a, the third protrusion 616c, the fourth protrusion 616d, and the sixth protrusion 616f is smaller than the circumferential width of the second protrusion 616b and the fifth protrusion 616e. A first positioning groove 618a is formed between the first protrusion 616a and the second protrusion 616b, between the second protrusion 616b and the third protrusion 616c, between the fourth protrusion 616d and the fifth protrusion 616e, and between the fifth protrusion 616e and the sixth protrusion 616f. A second positioning groove 618b is formed between the first protrusion 616a and the sixth protrusion 616f, and between the third protrusion 616c and the fourth protrusion 616d. The circumferential width of the first positioning groove 618a is smaller than the circumferential width of the second positioning groove 618b.

[0142] like Figure 23 As shown, four positioning protrusions 620a protruding downstream are provided at the downstream end of the first microbubble generating section 620. The four positioning protrusions 620a are disposed in the four first positioning grooves 618a of the main body housing 610 (see reference). Figure 22 The corresponding position has a shape corresponding to the four first positioning slots 618a.

[0143] like Figure 24 As shown, the swirling flow generating unit 650 has a shaft portion 352, an outer peripheral portion 354 surrounding the shaft portion 352, and six blade portions 356. Two upstream-side protrusions 654a protruding upstream are provided at the upstream end of the outer peripheral portion 354. The two upstream-side protrusions 654a are disposed in two second positioning grooves 618b of the main body housing 610 (see reference). Figure 22The corresponding position has a shape corresponding to the two second positioning slots 618b. For example... Figure 25 As shown, two downstream recesses 654b, recessed towards the upstream side, are provided at the downstream end of the outer peripheral portion 354. The two downstream recesses 654b are positioned corresponding to the two upstream protrusions 654a and have shapes corresponding to the two upstream protrusions 654a. That is, the upstream protrusions 654a (refer to...) Figure 24 It has a second positioning groove 618b that corresponds to the downstream recess 654b and the main housing 610 (see reference). Figure 22 The corresponding shapes of these two sides.

[0144] like Figure 26 As shown, the four positioning protrusions 620a of the first microbubble generating unit 620 engage with the four first positioning grooves 618a of the main body housing 10. That is, the first positioning grooves 618a and the positioning protrusions 620a are mechanisms for positioning the first microbubble generating unit 620 in the central axis A direction and the circumferential direction. The two upstream protrusions 654a of the second microbubble generating unit 622 (specifically, the upstream swirling flow generating unit 650) engage with the two second positioning grooves 618b of the main body housing 10. That is, the second positioning grooves 618b and the upstream protrusions 654a are mechanisms for positioning the second microbubble generating unit 622 (specifically, the upstream swirling flow generating unit 650) in the central axis A direction and the circumferential direction. Furthermore, as... Figure 27 As shown, the upstream protrusion 654a of the downstream swirling flow generating section 650 of the two adjacent swirling flow generating sections 650 in the direction of the central axis A engages with the downstream concave portion 654b of the upstream swirling flow generating section 650. That is, the upstream protrusion 654a and the downstream concave portion 654b are mechanisms for positioning the two adjacent swirling flow generating sections 650 in the direction of the central axis A and in the circumferential direction.

[0145] As mentioned above, such as Figure 21 As shown, the microbubble generating device 2 has a main housing 610 that houses the first microbubble generating section 620 and the second microbubble generating section 622. Figure 26As shown, the main housing 610 has a first positioning groove 618a (an example of "first positioning part") for positioning the first microbubble generating part 620 in the main housing 610 and a second positioning groove 618b (an example of "second positioning part") for positioning the second microbubble generating part 622 in the main housing 610. According to this structure, by positioning the first microbubble generating part 620 and the main housing 610 by the first positioning groove 618a and positioning the second microbubble generating part 622 and the main housing 610 by the second positioning groove 618b, the six outer Venturi portions 36 of the first microbubble generating part 620 and the six blade portions 356 of the upstream swirling flow generating part 650 of the second microbubble generating part 622 are positioned. Therefore, most of the dissolved water in the gas flowing out of the first microbubble generating section 620 can collide with the inflow end 362 of the blade portion 356 of the upstream swirling flow generating section 650, or be sheared as it passes through the inflow end 362 of the blade portion 356 of the upstream swirling flow generating section 650. Therefore, a large number of microbubbles can be generated.

[0146] In one or more embodiments, such as Figure 27 As shown, in each of the plurality of swirling flow generating units 650, an upstream-side protrusion 654a protruding upstream is provided at the upstream end, and a downstream-side recess 654b recessed upstream is provided at the downstream end. The upstream-side protrusion 654a has a shape corresponding to the second positioning groove 618b and the downstream-side recess 654b. According to the above structure, the main body housing 610 and the most upstream swirling flow generating unit 650 can be positioned using the upstream-side protrusion 654a of the swirling flow generating unit 650, and two adjacent swirling flow generating units 650 in the direction of the positioning center axis A can be positioned. In this case, it is not necessary to provide a different structure from the upstream-side protrusion 654a in order to position the main body housing 610 and the most upstream swirling flow generating unit 650 at the upstream end of the most upstream swirling flow generating unit 650. Therefore, the structure of the plurality of swirling flow generating units 650 can be common.

[0147] (Sixth Embodiment)

[0148] Reference Figure 28 , Figure 29 This describes the microbubble generator 2 of the sixth embodiment. The internal structure of the main housing 10 of the microbubble generator 2 in this embodiment is the same as that of the microbubble generator 2 of the first embodiment (see reference). Figure 2 )different.

[0149] like Figure 28As shown, the second microbubble generating unit 722 has three swirling flow generating units 50. A rectifier 770 is provided on the flow path 760 between the second microbubble generating unit 722 and the outflow unit 14. The flow path 760 is defined by the main body housing 10. The flow path axis of the flow path 760 is aligned with the central axis A. Figure 29 As shown, the rectifier 770 has a shaft portion 772, an outer peripheral portion 774 surrounding the shaft portion 772, six first rectifier walls 776, and six second rectifier walls 778. Figure 28 As shown, the outer diameter of the outer peripheral portion 774 is the same as the inner diameter of the main housing 10. The shaft portion 772 and the outer peripheral portion 774 are arranged along the central axis A. Figure 29 As shown, the first rectifier wall 776 and the second rectifier wall 778 extend radially inward from the inner wall of the outer peripheral portion 774. The first rectifier wall 776 and the second rectifier wall 778 have a flat plate shape along the radial and central axis A directions. The radially inward end of the first rectifier wall 776 is connected to the shaft portion 772. Six first rectifier walls 776 are arranged at equal intervals along the circumferential direction of the central axis A. The radially inward end of the second rectifier wall 778 is located radially outward from the outer wall of the shaft portion 772. The second rectifier wall 778 is disposed between two adjacent first rectifier walls 776 in the circumferential direction. Furthermore, in a modified example, more than two rectifiers 770 may be provided within the main housing 10.

[0150] As mentioned above, such as Figure 28As shown, the microbubble generator 2 has a rectifier 770 disposed between the second microbubble generating section 722 and the outlet section 14, which rectifies the flow of air-dissolved water flowing out of the second microbubble generating section 722 from a swirling flow flowing clockwise to a straight flow. The flow of air-dissolved water from the second microbubble generating section 722 to the rectifier 770 is a swirling flow (i.e., turbulent flow) flowing clockwise. When the flow of air-dissolved water is turbulent, compared to when the flow of air-dissolved water is a straight flow (i.e., laminar flow), the air-dissolved water is more likely to collide with the inner wall 14b (an example of a "wall") of the outlet section 14, which defines a flow path that causes the air-dissolved water to flow downstream of the rectifier 770. Therefore, when the flow of air-dissolved water exiting the second microbubble generating section 722 is not rectified from a swirling flow to a straight flow, a relatively large amount of air-dissolved water collides with the inner wall 14b of the outlet section 14. In this case, the pressure loss within the microbubble generating device 2 increases, and the amount of air-dissolved water flowing within the microbubble generating device 2 decreases. According to the above structure, by having the air-dissolved water exiting the second microbubble generating section 722 pass through the rectifier 770, the flow of air-dissolved water is rectified from a swirling flow to a straight flow. Therefore, the amount of air-dissolved water colliding with the inner wall 14b of the outlet section 14 can be reduced, thereby reducing the pressure loss within the microbubble generating device 2. Therefore, the amount of air-dissolved water flowing within the microbubble generating device 2 can be increased.

[0151] (Seventh Embodiment)

[0152] Reference Figure 30 This section describes the microbubble generator 2 of the seventh embodiment. The structure of the outlet 814 and the structure of the first microbubble generating section 820 of the microbubble generator 2 of this embodiment are the same as those of the microbubble generator 2 of the first embodiment (see reference 1). Figure 2 )different.

[0153] like Figure 30 As shown, the outflow section 814 has a first outflow path 816 and a second outflow path 818. The first outflow path 816 is a path extending along the central axis A. The second outflow path 818 is a path extending along a second central axis A2 orthogonal to the central axis A. In the following, it will sometimes be referred to as... Figure 30 The left and right sides are respectively designated as "first upstream direction" and "first downstream direction". Figure 30 The area below and above are respectively designated as "Second Upstream Direction" and "Second Downstream Direction".

[0154] The upstream end of the first outflow path 816 is connected to the downstream end of the second microbubble generating section 22, and the downstream end of the first outflow path 816 is connected to the upstream end of the second outflow path 818. An outlet 818a is formed at the downstream end of the second outflow path 818. A step portion 819 protruding in the first downstream direction is provided at the connection between the downstream end of the first outflow path 816 and the upstream end of the second outflow path 818. According to the above structure, the flow of air-dissolved water from the first outflow path 816 to the second outflow path 818 is obstructed by the step portion 819. As a result, the flow of air-dissolved water becomes turbulent near the inner wall 816a of the first outflow path 816. Consequently, the amount of air-dissolved water colliding with the inner wall 816a can be increased, and the amount of microbubbles can be increased.

[0155] The first microbubble generating unit 820 has a first main body 830 and a second main body 832. The outer wall 830a of the first main body 830 narrows from a first upstream direction to a first downstream direction. An upstream flange 834 is provided at the end of the outer wall 830a of the first main body 830 in the first upstream direction. The upstream flange 834 extends radially outward from the end of the outer wall 830a of the first main body 830 in the first upstream direction and is formed along the entire circumference. The outer circumferential surface of the upstream flange 834 abuts against the inner wall 10c of the main body housing 10. A first recess 834a with a radially inwardly recessed shape is provided in the upstream flange 834. The first recess 834a is provided at the center of the upstream flange 834 in the direction of the central axis A and is formed along the entire circumference. The outer wall 832a of the second main body 832 widens from a first upstream direction to a first downstream direction. A downstream flange 836 is provided at the end of the outer wall 832a of the second main body 832 in the first downstream direction. The downstream flange 836 extends radially outward from the end of the outer wall 832a of the second main body 832 in the first downstream direction and is formed along the entire circumference. The outer circumferential surface of the downstream flange 836 abuts against the inner wall 10c of the main body housing 10. A second recess 836a with an inwardly recessed shape is provided in the downstream flange 836. The second recess 836a is provided at the center of the downstream flange 836 in the direction of the central axis A and is formed along the entire circumference. A sealing member 838 is disposed in the first recess 834a and the second recess 836a. A space S is formed between the inner wall 10c of the main body housing 10 and the outer wall 830a of the first main body 830 and the outer wall 832a of the second main body 832.

[0156] Without a sealing member 838 in the first microbubble generating section 820, dissolved air water flowing into the first microbubble generating section 820 from the inlet 12 may sometimes seep into the space S, causing water to accumulate in the space S. When the dissolved air water accumulated in the space S freezes, its volume increases, and the main body shell 10 may be damaged. According to the above structure, water seepage into the space S can be suppressed. Therefore, damage to the main body shell 10 can be prevented.

[0157] The embodiments have been described in detail above, but these are merely illustrative examples and do not limit the technical solutions. The technology described in the technical solutions includes various modifications and alterations to the specific examples illustrated above.

[0158] (First Modification) The number of swirling flow generating units 50, 150, 250, and 350 in the second microbubble generating unit 22 is not limited to 4, but may be 2, 3, or 5 or more.

[0159] (Second variation) The number of blade sections 56 and 356 in the swirling flow generating sections 50, 150, 250 and 350 is not limited to 6, but may be 2 to 5 or more than 7.

[0160] (3rd Modification) The blade portions 56 and 356 of the swirling flow generating portions 50, 150, 250, and 350 may also tilt downstream as they gravitate in a counterclockwise direction. In this modification, the counterclockwise direction and the clockwise direction are examples of "prescribed swirling direction" and "opposite swirling direction," respectively.

[0161] (4th variation) The number of outer Venturi portions 36 of the first microbubble generating section 20 may be more or less than the number of blade portions 56 of the swirling flow generating section 50 of the second microbubble generating section 22.

[0162] (Fifth Modification) In the first embodiment, when the swirling flow generating section 50 is viewed from the direction of the central axis A, the six blade sections 56 of the second swirling flow generating section 50 can completely overlap with the six blade sections 56 of the first swirling flow generating section 50. The same applies to the second to fourth embodiments.

[0163] (Sixth Modification) The first microbubble generating section 20 may not have six outer Venturi portions 36, but only an inner Venturi portion 34. Alternatively, in another modification, the first microbubble generating section 20 may not have an inner Venturi portion 34, but only one or more outer Venturi portions 36.

[0164] (Seventh Modification) In the direction of the central axis A, the downstream ends of the six outer venturi portions 36 of the first microbubble generating section 20 may face the first opening 64 of the first swirling flow generating section 50 of the second microbubble generating section 22. In this case, the six outer venturi portions 36 may be inclined relative to the direction of the central axis A.

[0165] (Eighth Modification) The area of ​​the upstream end 52a of the shaft portion 52 of the first swirling flow generating section 50 of the second microbubble generating section 22 can be smaller than the opening area of ​​the downstream end of the inner Venturi portion 34 of the first microbubble generating section 20. Furthermore, in this modification, it is preferable that the area of ​​the shaft portion 52 of the swirling flow generating section 50, when viewed from the central axis A direction, is larger than the opening area of ​​the downstream end of the inner Venturi portion 34 of the first microbubble generating section 20. For example, the upstream end of the shaft portion 52 can have a hemispherical shape. Additionally, the shaft portion 52 can expand in diameter from upstream to downstream.

[0166] (9th variation) In the hot water system 402 of the first embodiment, the microbubble generator 2 may be installed in the water supply path 430, the hot water discharge path 450, the reheating path 460, the first bathtub circulation path 462 or the second bathtub circulation path 468.

[0167] (10th variation) In the dishwasher 510 of the first embodiment, the microbubble generator 2 may be provided in the first suction flow path 532 or the second suction flow path 574.

[0168] (11th Modification) In the 5th embodiment, an upstream recess that is recessed towards the downstream side can be provided at the upstream end of the swirling flow generating section 650, and a downstream protrusion that is protruding towards the downstream side can be provided at the downstream end. The upstream recess has a shape corresponding to the downstream protrusion. In this modification, the main body housing 10 can replace the first protrusion 616a to the sixth protrusion 616f and have an annular portion that protrudes radially inward from the inner wall 610c of the main body housing 610. Moreover, a protrusion that protrudes towards the downstream side and has a shape corresponding to the upstream recess can be provided on the downstream side surface of the annular portion (an example of the "second positioning portion"). According to this structure, it is not necessary to provide a different structure from the upstream recess in order to position the main body housing 610 and the upstreammost swirling flow generating section 650 at the upstream end of the upstreammost swirling flow generating section 650. Therefore, the structures of multiple swirling flow generating sections 650 can be common.

[0169] (12th variation) In the fifth embodiment, the upstream side protrusion 654a of the upstream side of the plurality of swirling flow generating parts 650 may have a shape corresponding to the second positioning groove 618b of the main body housing 610, but does not have a shape corresponding to the downstream side recess 654b of the swirling flow generating part 650.

[0170] (13th Modification) Main body shell 10 of the first embodiment (refer to) Figure 2 The device may have a first positioning part that positions the first microbubble generating part 20 to the main body housing 10 and a second positioning part that positions the second microbubble generating part 22 to the main body housing 10. With this structure, by positioning the first microbubble generating part 20 and the main body housing 10 by the first positioning part, and by positioning the second microbubble generating part 22 and the main body housing 10 by the second positioning part, the six outer Venturi portions 36 of the first microbubble generating part 20 and the six blade portions 56 of the upstream swirling flow generating part 50 of the second microbubble generating part 22 are positioned. Therefore, most of the dissolved water in the gas flowing out of the first microbubble generating part 20 can flow into the blade portions 56 of the upstream swirling flow generating part 50. Thus, a large quantity of microbubbles can be generated.

[0171] The technical elements described in this specification or drawings exert their technical usefulness individually or in various combinations, and are not limited to the combinations described in the technical solution at the time of the application. Furthermore, the technology illustrated in this specification or drawings can achieve multiple objectives simultaneously, and achieving any one of these objectives is itself technically useful.

Claims

1. A microbubble generator, characterized in that, It has an inflow section, an outflow section, a first microbubble generating section, and a second microbubble generating section, wherein, The inlet section is for gas-dissolving water to flow in; The outlet section is for the gas-dissolved water to flow out; The first microbubble generating section is disposed between the inflow section and the outflow section; The second microbubble generating section is disposed between the first microbubble generating section and the outflow section. The first microbubble generating section has a Venturi section, which has a narrowing flow path and an expanding flow path. The diameter of the narrowing flow path decreases from upstream to downstream. The expanding flow path is located downstream of the narrowing flow path, and its diameter increases from upstream to downstream. The second microbubble generating section has a plurality of swirling flow generating sections arranged along the downstream central axis of the second microbubble generating section. The plurality of swirling flow generating sections each have a shaft section, an outer peripheral section, and a plurality of blade sections, wherein... The shaft extends along the downstream central axis direction; The outer peripheral portion surrounds the shaft portion; The plurality of blade portions are disposed between the shaft portion and the outer peripheral portion, generating a swirling flow that flows relative to the shaft portion in a predetermined swirling direction. When the direction opposite to the specified direction of rotation is taken as the opposite direction of rotation. The plurality of blades in the swirling flow generating section are respectively configured such that the end of a specific blade in the swirling direction is located on the opposite side of the end of the blade adjacent to the specific blade in the swirling direction. When viewed from the downstream central axis direction, the swirling flow generating section is provided with a plurality of first openings. When the swirling flow generating section is viewed from the downstream central axis direction, the plurality of first openings are respectively surrounded by the end of the specific blade section on the swirling direction side, the end of the adjacent blade section on the opposite swirling direction side, the shaft section, and the outer peripheral section. When the second microbubble generating section is viewed from the direction of the downstream central axis, the multiple blades of the downstream swirling flow generating section, which is different from the swirling flow generating section located on the upstream side, are respectively configured such that, on the upstream side of the downstream swirling flow generating section, at least a portion of the corresponding first opening of the multiple first openings of the upstream swirling flow generating section adjacent to the downstream swirling flow generating section overlaps with at least a portion of the corresponding first opening of the upstream swirling flow generating section adjacent to the downstream swirling flow generating section.

2. The microbubble generator according to claim 1, characterized in that, When the second microbubble generating section is viewed from the downstream central axis direction, the plurality of blades of the downstream swirling flow generating section are respectively configured to overlap with the corresponding first opening of the plurality of first openings of the upstream swirling flow generating section.

3. The microbubble generator according to claim 1, characterized in that, The downstream end of the swirling flow generating section is provided with multiple second openings. The plurality of second openings are respectively surrounded by the end portion of the specific blade portion on the rotation direction side, the end portion of the adjacent blade portion on the rotation direction side, the shaft portion, and the outer peripheral portion. When the second microbubble generating section is viewed from the downstream central axis direction, the ends of the multiple blades of the downstream swirling flow generating section on the opposite swirling direction side are located near the center of the corresponding second opening in the swirling direction among the multiple second openings.

4. A microbubble generator, characterized in that, It has an inflow section, an outflow section, a first microbubble generating section, and a second microbubble generating section, wherein, The inlet section is for gas-dissolving water to flow in; The outlet section is for the gas-dissolved water to flow out; The first microbubble generating section is disposed between the inflow section and the outflow section; The second microbubble generating section is disposed between the first microbubble generating section and the outflow section. The first microbubble generating section has a Venturi section, which has a narrowing flow path and an expanding flow path. The diameter of the narrowing flow path decreases from upstream to downstream. The expanding flow path is located downstream of the narrowing flow path, and its diameter increases from upstream to downstream. The second microbubble generating section has a plurality of swirling flow generating sections arranged along the downstream central axis of the second microbubble generating section. The plurality of swirling flow generating sections each have a shaft section, an outer peripheral section, and a plurality of blade sections, wherein... The shaft extends along the downstream central axis direction; The outer peripheral portion surrounds the shaft portion; The plurality of blade portions are disposed between the shaft portion and the outer peripheral portion, generating a swirling flow that flows relative to the shaft portion in a predetermined swirling direction. The first microbubble generating section has a plurality of Venturi portions. The plurality of Venturi portions include a plurality of outer Venturi portions arranged around the central axis of the first microbubble generating portion, i.e., the upstream central axis. The number of the plurality of outer venturi portions is the same as the number of the plurality of blade portions in the upstreammost swirling flow generating section of the plurality of swirling flow generating sections. The downstream end of the expansion flow path of each of the plurality of outer venturi portions faces the corresponding blade portion of the plurality of blade portions of the upstream swirling flow generating portion.

5. A microbubble generator, characterized in that, It has an inflow section, an outflow section, a first microbubble generating section, and a second microbubble generating section, wherein, The inlet section is for gas-dissolving water to flow in; The outlet section is for the gas-dissolved water to flow out; The first microbubble generating section is disposed between the inflow section and the outflow section; The second microbubble generating section is disposed between the first microbubble generating section and the outflow section. The first microbubble generating section has a Venturi section, which has a narrowing flow path and an expanding flow path. The diameter of the narrowing flow path decreases from upstream to downstream. The expanding flow path is located downstream of the narrowing flow path, and its diameter increases from upstream to downstream. The second microbubble generating section has a plurality of swirling flow generating sections arranged along the downstream central axis of the second microbubble generating section. The plurality of swirling flow generating sections each have a shaft section, an outer peripheral section, and a plurality of blade sections, wherein... The shaft extends along the downstream central axis direction; The outer peripheral portion surrounds the shaft portion; The plurality of blade portions are disposed between the shaft portion and the outer peripheral portion, generating a swirling flow that flows relative to the shaft portion in a predetermined swirling direction. The first microbubble generating section has a plurality of Venturi portions. The plurality of Venturi portions include a plurality of outer Venturi portions arranged around the central axis of the first microbubble generating portion, i.e., the upstream central axis. The number of the plurality of outer venturi portions is the same as the number of the plurality of blade portions in the upstreammost swirling flow generating section of the plurality of swirling flow generating sections. The downstream end of the expansion flow path of each of the plurality of outer venturi portions faces the end of the corresponding blade portion of the plurality of blade portions of the upstream swirling flow generating portion in the opposite direction of swirling.

6. The microbubble generator according to claim 4 or 5, characterized in that, The microbubble generating device also has a main housing that houses the first microbubble generating section and the second microbubble generating section. The main housing has a first positioning part and a second positioning part, wherein, The first positioning part is used to position the first microbubble generating part on the main body shell; The second positioning part is used to position the second microbubble generating part on the main body shell.

7. The microbubble generator according to claim 6, characterized in that, In each of the plurality of swirling flow generating sections, An upstream convex portion protruding upstream or an upstream concave portion recessed downstream is provided at the upstream end. At the downstream end, when the upstream side protrusion is provided at the upstream end of the swirling flow generating section, a downstream side recess that is recessed towards the upstream side is provided; when the upstream side recess is provided at the upstream end of the swirling flow generating section, a downstream side protrusion that is protruding towards the downstream side is provided. The upstream convex portion has a shape corresponding to the second positioning portion and the downstream concave portion. The upstream side recess has a shape corresponding to the second positioning part and the downstream side protrusion.

8. The microbubble generator according to claim 4 or 5, characterized in that, The plurality of venturi portions further include an inner venturi portion extending along the upstream central axis. The downstream end of the expansion flow path in the inner venturi portion faces the axial portion of the upstream swirling flow generating portion. The opening area at the downstream end of the expanded flow path in the inner venturi portion is smaller than the area of ​​the axial portion of the upstream swirling flow generating portion when viewed from the downstream central axis direction.

9. The microbubble generator according to claim 8, characterized in that, The opening area is smaller than the area of ​​the upstream end of the shaft portion of the upstream swirling flow generating section when viewed from the downstream central axis direction.

10. The microbubble generator according to claim 9, characterized in that, The upstream end of the shaft portion of the upstream swirling flow generating section is provided with a recess that extends downstream.

11. The microbubble generator according to claim 1, 4, or 5, characterized in that, The upstream side of each of the plurality of blades is provided with a protrusion that protrudes upstream.

12. The microbubble generator according to claim 11, characterized in that, The first microbubble generating section has a plurality of Venturi portions. The plurality of Venturi portions include a plurality of outer Venturi portions arranged around the central axis of the first microbubble generating portion, i.e., the upstream central axis. The number of the plurality of outer venturi portions is the same as the number of the plurality of blade portions in the upstreammost swirling flow generating section of the plurality of swirling flow generating sections. The downstream end of the expansion flow path of each of the plurality of outer venturi portions faces the protrusion provided on the corresponding blade portion of the plurality of blade portions of the upstream swirling flow generating portion.

13. The microbubble generator according to claim 1, 4, or 5, characterized in that, The microbubble generator also has a rectifier. The rectifier is located between the second microbubble generating section and the outflow section, and rectifies the flow of dissolved water in gas flowing out of the second microbubble generating section from a swirling flow to a straight flow.

14. A water heater, characterized in that, The microbubble generating apparatus having any one of claims 1 to 13.

15. A dishwasher, characterized in that, The microbubble generating apparatus having any one of claims 1 to 13.

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