Fluid treatment apparatus, microbubble generation device, and shower head

Abstract

To sufficiently improve fluid treatment efficiency on a fluid treatment apparatus including a Venturi tube.SOLUTION: A fluid treatment apparatus includes: a Venturi tube including a throat part; and a swirl flow generating part. The swirl flow generating part is disposed upstream of the Venturi tube to generate a swirl flow having a ratio (v / u) of a flow velocity v in a swirl direction to a flow velocity u in an axial direction in the throat part being less than 1 in the supplied fluid.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The technology disclosed in this specification relates to a fluid treatment device, a microbubble generator, and a showerhead. [Background technology]

[0002] A microbubble generator for showerheads that uses a Venturi tube is known (see, for example, Patent Document 1). In a microbubble generator using a Venturi tube, cavitation occurs in the throat of the Venturi tube (the part with the smallest flow path cross-sectional area) as the flow rate increases, causing a decrease in pressure, and the air dissolved in the water becomes microbubbles. In this specification, microbubbles refer to fine bubbles with a diameter of 100 μm or less. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-115771 A Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional microbubble generators using a Venturi tube have the problem that they are unable to sufficiently reduce the pressure at the throat of the Venturi tube, and are therefore unable to generate sufficient microbubbles.

[0005] Such a problem is not limited to microbubble generators, but is a common problem to fluid treatment devices that use a Venturi tube to perform some kind of treatment on a fluid. That is, in conventional fluid treatment devices that use a Venturi tube, the pressure at the throat of the Venturi tube cannot be sufficiently reduced, and the fluid treatment efficiency cannot be sufficiently improved.

[0006] This specification discloses a technique that can solve the above-mentioned problems. [Means for solving the problem]

[0007] The technology disclosed in this specification can be realized, for example, in the following forms.

[0008] (1) A fluid processing device disclosed in this specification includes a Venturi tube having a throat, and a swirl flow generating unit. The swirl flow generating unit is disposed upstream of the Venturi tube and generates a swirl flow in a supplied fluid, in which the ratio (v / u) of a flow velocity v in a swirling direction to a flow velocity u in an axial direction at the throat is less than 1.

[0009] Thus, in this fluid processing device, a swirling flow generating section is disposed upstream of the Venturi tube, and the swirling flow generating section generates a relatively weak swirling flow (a swirling flow in which the above-mentioned ratio (v / u) is less than 1) in the supplied fluid. Therefore, due to the presence of the relatively weak swirling flow, separation of the fluid flow from the inner wall surface of the Venturi tube can be suppressed even if the taper angle of the Venturi tube is relatively large. Therefore, according to this fluid processing device, the effect of the diffuser in the Venturi tube can be increased to effectively reduce the pressure in the throat, and as a result, fluid processing can be performed efficiently.

[0010] (2) In the above fluid processing device, the swirling flow generating section may be configured to generate a swirling flow in the supplied fluid, in which the ratio (V / U) of a flow velocity V in the swirling direction to a flow velocity U in the axial direction in the swirling flow generating section is less than 1. If this configuration is adopted, the presence of an even weaker swirling flow effectively suppresses separation of the fluid flow from the inner wall surface of the Venturi tube, while allowing the taper angle of the Venturi tube to be relatively large, and the pressure in the throat of the Venturi tube can be effectively reduced, resulting in more efficient fluid processing.

[0011] (3) In the above-mentioned fluid treatment device, the swirling flow generating section may be configured to include a tubular section and at least one vane housed in the tubular section and having a surface inclined with respect to the axial direction so as to generate the swirling flow. By adopting this configuration, a relatively weak swirling flow can be reliably generated with a simple configuration.

[0012] (4) In the above fluid treatment device, the vane is t max / D min <1 / 5 (where t max is the maximum plate thickness of the vane, and D min is the minimum value of the inner diameter of the swirl flow generating portion.) By adopting this configuration, the plate thickness of the vane is relatively thin, the pressure loss in the swirl flow generating portion can be reduced, the pressure in the throat of the Venturi tube can be reduced more effectively, and the fluid can be treated more efficiently.

[0013] (5) In the above fluid treatment device, in at least one longitudinal section of the vane, the contour line of the downstream end of the vane may have a portion bent at an acute angle. By adopting this configuration, it is possible to promote cavitation at the downstream end of the vane, and to perform fluid treatment more efficiently.

[0014] (6) In the above-mentioned fluid treatment device, the swirling flow generating section may have a cylindrical section located at the center of the swirling flow generating section and extending in the axial direction, and a bullet-shaped section located downstream of the vane and the cylindrical section and tapering toward the downstream side. By adopting this configuration, the presence of the bullet-shaped section can suppress the pressure drop downstream of the vane, and the pressure at the throat of the Venturi tube can be reduced more effectively, thereby making it possible to more efficiently treat the fluid.

[0015] (7) In the above fluid treatment device, the distance L from the downstream end of the vane to the upstream end of the Venturi tube sw D min ·cotθ is greater than (where Dmin is the minimum value of the inner diameter of the swirl flow generating portion.) By adopting this configuration, the vane is disposed relatively far from the Venturi tube, so that the swirl flow can be stably formed on the upstream side of the Venturi tube, the pressure at the throat of the Venturi tube can be reduced more effectively, and the fluid can be treated more efficiently.

[0016] (8) In the above-mentioned fluid processing device, the taper angle ψ of the Venturi tube may be 10 degrees or more. In a normal Venturi tube, in order to increase the amount of microbubbles, it is necessary to increase the taper angle ψ. However, if the taper angle ψ is set to 10 degrees or more, the fluid separates at the taper section downstream of the throat, and the pressure at the throat cannot be sufficiently reduced, and a large amount of microbubbles cannot be generated. By adopting this configuration, even if the taper angle ψ of the Venturi tube is set to 10 degrees or more, the separation of the fluid is suppressed by the swirling flow, so that the pressure at the throat can be sufficiently reduced (the pressure can be sufficiently reduced to the same extent as in a configuration in which the taper angle ψ is less than 10 degrees), and the amount of microbubbles generated can be increased.

[0017] The techniques disclosed in this specification can be realized in various forms, for example, in the form of a fluid processing device, a microbubble generator, a shower head, a fluid mixing device, and methods of manufacturing and using the same. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is an explanatory diagram illustrating a schematic configuration of a shower head 10 according to a first embodiment. [Diagram 2] FIG. 1 is an explanatory diagram showing a vertical cross-sectional configuration of a microbubble generator 100 according to a first embodiment. [Diagram 3] FIG. 1 is an explanatory diagram showing the configuration of a microbubble generator 100X according to a comparative example. [Figure 4] FIG. 13 is an explanatory diagram showing a vertical cross-sectional configuration of a microbubble generator 100a according to a second embodiment. [Diagram 5] FIG. 11 is an explanatory diagram showing a front configuration of a swirling flow generating section 110a according to a second embodiment; [Figure 6] FIG. 11 is an explanatory diagram showing the performance evaluation results for the vane angle θ of the vane 113 of the swirl flow generating portion 110. [Figure 7] FIG. 13 is an explanatory diagram showing the performance evaluation results for the taper angle ψ of the Venturi tube 120. [Figure 8] FIG. 13 is an explanatory diagram showing the performance evaluation results for the taper angle ψ of the Venturi tube 120. [Figure 9] FIG. 13 is an explanatory diagram showing the performance evaluation results of the bullet-shaped portion 117 of the swirl flow generating portion 110. [Figure 10] An explanatory diagram showing the performance evaluation results of microbubble generation [Figure 11] An explanatory diagram showing the performance evaluation results of microbubble generation [Figure 12] An explanatory diagram showing the performance evaluation results of microbubble generation [Figure 13] An explanatory diagram showing the performance evaluation results of microbubble generation [Figure 14] FIG. 1 is an explanatory diagram showing the configuration of a fluid mixing device 102 as a fluid processing device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] A. First embodiment: A-1. Shower head 10 configuration: Fig. 1 is an explanatory diagram showing the schematic configuration of a showerhead 10 according to a first embodiment. Fig. 1 shows a cross-sectional configuration (and a portion of a side configuration) of the showerhead 10. The showerhead 10 is a device that is connected to the end of a shower hose (water supply pipe) (not shown) and discharges water (including hot water) supplied through the shower hose as shower water.

[0020] Shower head 10 includes a head portion 11, a grip portion 12, and a hose connection portion 13. Grip portion 12 is a generally rod-shaped portion that is held by a user. Hose connection portion 13 is provided at one end of grip portion 12. A shower hose (not shown) is connected to hose connection portion 13. Head portion 11 is provided at the other end of grip portion 12. Head portion 11 has a water discharge surface 14, and multiple water discharge holes 15 are formed in water discharge surface 14.

[0021] The shower head 10 further includes a microbubble generator 100, an upstream water passage section 16 connected to the upstream side of the microbubble generator 100, and a downstream water passage section 17 connected to the downstream side of the microbubble generator 100.

[0022] The microbubble generator 100 is a device that generates microbubbles in water supplied through an upstream water passage section 16 and discharges the water containing the microbubbles toward the water discharge hole 15 through a downstream water passage section 17. The microbubble generator 100 is an example of a fluid processing device. In this embodiment, the microbubble generator 100 is housed in the grip section 12. However, the microbubble generator 100 may be disposed in the head section 11.

[0023] Fig. 2 is an explanatory diagram showing a vertical cross-sectional configuration of the microbubble generator 100 of the first embodiment. The microbubble generator 100 includes a Venturi tube 120 and a swirling flow generating section 110. The Venturi tube 120 and the swirling flow generating section 110 are arranged coaxially. Fig. 2 shows a central axis Ax of the microbubble generator 100 (the swirling flow generating section 110 and the Venturi tube 120). Hereinafter, the direction from the upstream side to the downstream side in the microbubble generator 100 (the direction parallel to the central axis Ax) is also referred to as the axial direction.

[0024] The Venturi tube 120 is a tubular mechanism that increases the flow velocity by throttling the flow of a fluid supplied from the upstream side, thereby generating low pressure in the portion where the flow is throttled. The Venturi tube 120 has an upstream tapered portion 121, a throat portion 122, and a downstream tapered portion 123.

[0025] The upstream taper section 121 is a tapered section whose flow path cross-sectional area gradually decreases from the upstream side to the downstream side. The throat section 122 is connected to the downstream end of the upstream taper section 121 and is a section having the smallest flow path cross-sectional area in the Venturi tube 120. The throat section 122 may have a predetermined length in the axial direction, or may be a section that has substantially no length in the axial direction. The downstream taper section 123 is connected to the downstream end of the throat section 122 and is a tapered section whose flow path cross-sectional area gradually increases from the upstream side to the downstream side. Hereinafter, in a vertical cross section (for example, the cross section shown in FIG. 2) including the central axis Ax of the microbubble generator 100, the opening angle ψ (in this embodiment, twice the angle between the inner wall surface 124 and the central axis Ax) of the inner wall surface 124 of the downstream taper section 123 of the Venturi tube 120 is referred to as the taper angle ψ of the Venturi tube 120. The taper angle ψ of the Venturi tube 120 is set to a relatively large value, for example, 10 degrees or more. The taper angle ψ of the Venturi tube 120 may be 20 degrees or more, 30 degrees or more, or 45 degrees or more. In addition, the taper angle ψ of the Venturi tube 120 may be less than 80 degrees, less than 70 degrees, or less than 60 degrees.

[0026] The Venturi tube 120 generates microbubbles in water supplied from the upstream side. That is, as the flow rate increases, the pressure decreases at the throat 122 of the Venturi tube 120, causing cavitation, and the air dissolved in the water becomes microbubbles. The Venturi tube 120 is connected to the downstream water passage 17 (FIG. 1) arranged downstream of the microbubble generator 100, and the water containing the microbubbles generated in the Venturi tube 120 is supplied to the water outlet 15 via the downstream water passage 17.

[0027] The swirling flow generating unit 110 is a device that generates a swirling flow in a fluid supplied from the upstream side. The swirling flow is a fluid flow that rotates around the central axis Ax of the microbubble generator 100. The swirling flow generating unit 110 is connected to the upstream end of the Venturi tube 120. The water flow to which the swirling flow has been imparted in the swirling flow generating unit 110 is supplied to the Venturi tube 120. The inner diameter D of the swirling flow generating unit 110 is larger than the inner diameter d of the throat portion 122 of the Venturi tube 120.

[0028] The swirling flow generating section 110 of this embodiment is configured to generate a relatively weak swirling flow in the water supplied from the upstream side. Specifically, the swirling flow generating section 110 is configured to generate a swirling flow in the water supplied from the upstream side, in which the ratio (v / u) of the flow velocity v in the swirling direction to the flow velocity u in the central axis Ax direction at the throat 122 of the Venturi tube 120 is less than 1. The swirling flow generating section 110 may also be configured to generate an even weaker swirling flow in the water supplied from the upstream side. Specifically, the swirling flow generating section 110 may also be configured to generate a swirling flow in the water supplied from the upstream side, in which the ratio (V / U) of the flow velocity V in the swirling direction to the flow velocity U in the central axis Ax direction at the swirling flow generating section 110 is less than 1. Note that, according to the conservation laws of mass and angular momentum, the relationship of ratio (v / u)<ratio (V / U) holds. Hereinafter, the ratio of the flow velocity in the swirling direction to the flow velocity in the central axis Ax direction will be referred to as the swirl parameter S. w It is also called.

[0029] The swirling flow generating section 110 includes a substantially cylindrical tubular section 111 and a wing body 112 housed in the tubular section 111. The wing body 112 has at least one vane 113. The vane 113 is a wing having a surface 114 inclined with respect to the direction of the central axis Ax. The surface 114 of the vane 113 is substantially parallel to the central axis Ax in the upstream portion, and is inclined with respect to the direction of the central axis Ax in the downstream portion. Hereinafter, in a vertical section (for example, the section shown in FIG. 2) including the central axis Ax of the microbubble generator 100, the maximum value of the angle between the surface 114 of the vane 113 and the central axis Ax is referred to as the vane angle θ of the vane 113. In this embodiment, the wing body 112 has four vanes 113. Each vane 113 is disposed substantially evenly around the central axis Ax. In addition, the vane angles θ of each vane 113 are substantially the same as each other.

[0030] The larger the vane angle θ of each vane 113 of the blade body 112, the greater the swirl parameter S w The ratio (V / U) of the flow velocity V in the swirling direction to the flow velocity U in the direction of the central axis Ax becomes large, and the swirl parameter S w In other words, the larger the vane angle θ of each vane 113 of the wing body 112, the stronger the swirling flow that is generated. Conversely, the smaller the vane angle θ of each vane 113 of the wing body 112, the weaker the swirling flow that is generated. In this embodiment, the vane angle θ of each vane 113 is set so that the supplied water has the above-mentioned relatively weak swirling flow (swirl parameter S at the throat 122 of the Venturi tube 120). w The vane angle θ of each vane 113 is set so that the supplied water is subjected to a swirl parameter S w The vane angle θ may be set so as to generate a swirling flow in which the vane angle θ is less than 1. The vane angle θ may be equal to or greater than 20 degrees, or may be equal to or greater than 30 degrees. In addition, the vane angle θ may be less than 60 degrees, or may be less than 45 degrees.

[0031] In this embodiment, each vane 113 of the wing body 112 has a relatively thin plate shape. Specifically, each vane 113 is configured to satisfy the following formula (1). t max / D min <1 / 5 ···(1) (However, t max is the maximum thickness t of the vane 113, D min is the minimum value of the inner diameter of the swirl flow generating portion 110.)

[0032] In this embodiment, the downstream end of each vane 113 of the wing body 112 forms a sharp edge. Specifically, in at least one longitudinal section of the vane 113, the contour line of the downstream end of the vane 113 has a portion 115 bent at an acute angle.

[0033] In this embodiment, a predetermined distance or more is ensured between each vane 113 of the blade body 112 and the Venturi tube 120. Specifically, the distance L from the downstream end of the vane 113 to the upstream end of the Venturi tube 120 is sw D min -Cotθ is over.

[0034] A-2. Operation of shower head 10: When water is supplied to the shower head 10 through a shower hose (not shown) connected to the hose connection part 13 (FIG. 1) of the shower head 10, the water flows into the microbubble generator 100 through the upstream water passage part 16.

[0035] A swirling flow is imparted to the water that has flowed into the microbubble generator 100 in the swirling flow generating section 110. When the water to which a swirling flow has been imparted is supplied to the Venturi tube 120, the water flows from the upstream taper section 121 to the throat section 122, and as the flow rate increases, the pressure decreases, causing cavitation. The air dissolved in the water turns into microbubbles, and the water containing the microbubbles is discharged through the downstream taper section 123.

[0036] The water containing microbubbles discharged from the Venturi tube 120 reaches the water discharge surface 14 via the downstream water passage 17, and is discharged to the outside from a plurality of water discharge holes 15 formed in the water discharge surface 14.

[0037] A-3. Advantages of this embodiment: As described above, the microbubble generator 100 constituting the showerhead 10 of this embodiment includes the Venturi tube 120 and the swirling flow generating unit 110. The swirling flow generating unit 110 is disposed upstream of the Venturi tube 120. The swirling flow generating unit 110 generates a swirling flow in the supplied water, in which the ratio (v / u) of the flow velocity v in the swirling direction to the flow velocity u in the axial direction at the throat 122 of the Venturi tube 120 is less than 1. Therefore, as described in detail below, according to the microbubble generator 100 of this embodiment, the pressure at the throat 122 of the Venturi tube 120 can be effectively reduced, and microbubbles can be effectively generated.

[0038] 3 is an explanatory diagram showing the configuration of a microbubble generator 100X of a comparative example. The microbubble generator 100X of the comparative example differs from the microbubble generator 100 of this embodiment in that it does not have a swirling flow generating part 110. In the microbubble generator 100X of the comparative example, the taper angle ψ of the Venturi tube 120 is set to a relatively large value (for example, 10 degrees or more) like the microbubble generator 100 of this embodiment.

[0039] In the microbubble generator 100X of the comparative example, a straight water flow that does not substantially include a swirling flow is supplied to the Venturi tube 120. At this time, as in the microbubble generator 100 of the present embodiment, as the flow rate increases when the water flows from the upstream taper section 121 to the throat section 122, the pressure decreases and cavitation occurs, the air dissolved in the water becomes microbubbles, and the water containing the microbubbles is discharged through the downstream taper section 123. However, since the water flow supplied to the Venturi tube 120 does not substantially include a swirling flow, separation of the water flow FL from the inner wall surface 124 occurs in the downstream taper section 123 of the Venturi tube 120. Therefore, in the microbubble generator 100X of the comparative example, the pressure in the throat section 122 of the Venturi tube 120 cannot be effectively reduced, and microbubbles cannot be effectively generated.

[0040] In contrast, in the microbubble generator 100 of this embodiment, the swirling flow generating section 110 is disposed upstream of the Venturi tube 120. The swirling flow generating section 110 generates a relatively weak swirling flow (a swirling flow in which the ratio (v / u) is less than 1) in the supplied water. Therefore, as shown in FIG. 2, in the microbubble generator 100 of this embodiment, even if the taper angle ψ of the Venturi tube 120 is relatively large (for example, even if it is 10 degrees or more), the presence of a relatively weak swirling flow can suppress separation of the water flow FL from the inner wall surface 124 in the downstream taper section 123 of the Venturi tube 120. Therefore, according to the microbubble generator 100 of this embodiment, the effect of the diffuser in the Venturi tube 120 can be increased to effectively reduce the pressure in the throat section 122, and as a result, the efficiency of generating microbubbles by the Venturi tube 120 can be improved. The mechanism by which the separation of the water flow FL from the inner wall surface 124 at the downstream taper section 123 of the Venturi tube 120 can be suppressed by imparting a swirling flow to the water flow supplied to the Venturi tube 120 is not entirely clear, but it is thought that this is due to the Coanda effect, in which the swirling flow jet is attracted to the wall surface.

[0041] Moreover, in the microbubble generator 100 of this embodiment, the swirling flow generating section 110 is configured to generate a swirling flow in the supplied fluid, in which the ratio (V / U) of the flow velocity V in the swirling direction to the flow velocity U in the axial direction in the swirling flow generating section 110 is less than 1. Therefore, according to the microbubble generator 100 of this embodiment, the presence of an even weaker swirling flow effectively suppresses separation of the water flow FL from the inner wall surface 124 in the downstream taper section 123 of the Venturi tube 120, while making the taper angle ψ of the Venturi tube 120 relatively large, and the pressure in the throat section 122 of the Venturi tube 120 can be reduced even more effectively, resulting in even more effective generation of microbubbles.

[0042] Moreover, in the microbubble generator 100 of this embodiment, the swirling flow generating part 110 includes a tubular part 111 and at least one vane 113 housed in the tubular part 111. The vane 113 has a surface 114 that is inclined with respect to the direction of the central axis Ax so as to generate the above-mentioned relatively weak swirling flow. Therefore, according to the microbubble generator 100 of this embodiment, a relatively weak swirling flow can be reliably generated with a simple configuration.

[0043] In the microbubble generator 100 of this embodiment, the vane 113 has a diameter of t max / D min <1 / 5 (where t max is the maximum plate thickness t of the vane 113, and D min is the minimum value of the inner diameter of the swirling flow generating part 110.) Therefore, according to the microbubble generator 100 of this embodiment, the plate thickness t of the vane 113 is relatively thin, and the pressure loss of the swirling flow generating part 110 can be reduced. Therefore, the pressure in the throat part 122 of the Venturi tube 120 can be reduced more effectively, and microbubbles can be generated more effectively.

[0044] In the microbubble generator 100 of this embodiment, in at least one longitudinal section of the vane 113, the contour line of the downstream end of the vane 113 has an acutely angled portion 115. Therefore, according to the microbubble generator 100 of this embodiment, it is possible to promote cavitation at the downstream end of the vane 113, and to generate microbubbles more effectively.

[0045] In the microbubble generator 100 of this embodiment, the distance L from the downstream end of the vane 113 of the swirling flow generating section 110 to the upstream end of the Venturi tube 120 is sw D min Therefore, according to the microbubble generator 100 of this embodiment, by disposing the vane 113 relatively far from the Venturi tube 120, a swirling flow can be stably formed on the upstream side of the Venturi tube 120. Therefore, the pressure in the throat 122 of the Venturi tube 120 can be reduced more effectively, and microbubbles can be generated more effectively.

[0046] B. Second embodiment: Fig. 4 is an explanatory diagram showing a vertical cross-sectional configuration of a microbubble generator 100a of the second embodiment. Fig. 5 is an explanatory diagram showing a front configuration of a swirling flow generating unit 110a of the second embodiment. In the following, among the configurations of the microbubble generator 100a of the second embodiment, the same configurations as those of the microbubble generator 100 of the first embodiment described above are denoted by the same reference numerals and the description thereof will be omitted as appropriate.

[0047] The microbubble generator 100a of the second embodiment differs from the microbubble generator 100 of the first embodiment in the configuration of the swirling flow generating part 110a. Specifically, in the microbubble generator 100a of the second embodiment, the swirling flow generating part 110a has a cylindrical part 116 and a shell-shaped part 117. The cylindrical part 116 is located at the center of the swirling flow generating part 110a and is a cylindrical part extending in the direction of the central axis Ax. Each vane 113 is fixed to the outer circumferential surface of the cylindrical part 116. The shell-shaped part 117 is located downstream of the vane 113 and the cylindrical part 116 and is a shell-shaped part whose diameter decreases toward the downstream side.

[0048] In the microbubble generator 100a of the second embodiment, the presence of the bullet-shaped part 117 can suppress the pressure drop downstream of the vane 113. Therefore, according to the microbubble generator 100a of the second embodiment, the pressure in the throat part 122 of the Venturi tube 120 can be more effectively reduced, and microbubbles can be more effectively generated.

[0049] C. Performance evaluation: The microbubble generators of the above-mentioned respective embodiments were prototyped and various performance evaluations were carried out.

[0050] 6 is an explanatory diagram showing the performance evaluation results for the vane angle θ of the vane 113 of the swirling flow generating part 110. FIG. 6 shows the relationship between the upstream pressure (gauge pressure) P0 and the flow rate (volume flow rate) Q of the microbubble generator 100 when the configuration (configuration of the first embodiment) not having the cylindrical part 116 and the bullet-shaped part 117 is adopted as the swirling flow generating part 110, the inner diameter D of the swirling flow generating part 110 is fixed to 3 mm, the taper angle ψ of the Venturi tube 120 is fixed to 10 degrees, and the vane angle θ is varied. In the performance evaluation described in this specification, the inner diameter D of the swirling flow generating part 110 and the inner diameter d of the throat part 122 of the Venturi tube 120 are set to have a relationship of D=2d.

[0051] As shown in FIG. 6, regardless of the vane angle θ, the flow rate Q increases as the upstream pressure P0 increases. Also, the flow rate Q at a certain upstream pressure P0 tends to decrease as the vane angle θ increases. This is believed to be because the pressure loss in the swirl flow generating section 110 increases as the vane angle θ increases. Referring to FIG. 6, it can be seen that if the vane angle θ is less than 45 degrees, the flow rate Q at a certain upstream pressure P0 does not change much, but if the vane angle θ is 45 degrees or more, the degree of decrease in the flow rate Q at a certain upstream pressure P0 increases. Referring to this result, it can be said that the vane angle θ is preferably less than 60 degrees, and more preferably less than 45 degrees.

[0052] 7 and 8 are explanatory diagrams showing the performance evaluation results for the taper angle ψ of the Venturi tube 120. Fig. 7 and Fig. 8 respectively show the relationship between the upstream pressure P0 and the pressure P1 of the throat 122 of the microbubble generator 100 when the inner diameter D of the swirling flow generating part 110 is fixed to 3 mm, the vane angle θ of the swirling flow generating part 110 is fixed to 30 degrees, and the taper angle ψ is varied in the case of adopting a configuration (configuration of the first embodiment) without the bullet-shaped part 117 as the swirling flow generating part 110 and a configuration (configuration of the second embodiment) with the bullet-shaped part 117 as the swirling flow generating part 110.

[0053] 7 and 8, pressure P1 at throat 122 of Venturi tube 120 is sufficiently small regardless of taper angle ψ. With reference to this result, it can be said that by arranging swirl flow generating section 110 on the upstream side of Venturi tube 120, pressure P1 at throat 122 of Venturi tube 120 can be effectively reduced regardless of taper angle ψ, and as a result, microbubbles can be effectively generated.

[0054] Fig. 9 is an explanatory diagram showing the performance evaluation results for the bullet-shaped portion 117 of the swirling flow generating portion 110. Fig. 9 shows the relationship between the upstream pressure P0 and the flow rate Q of the microbubble generator 100 when the inner diameter D of the swirling flow generating portion 110 is fixed to 3 mm, the vane angle θ of the swirling flow generating portion 110 is fixed to 30 degrees, and the taper angle ψ of the Venturi tube 120 is varied in the case where a configuration not having the bullet-shaped portion 117 is adopted as the swirling flow generating portion 110 (configuration of the first embodiment, shown as "E1" in Fig. 9) and a configuration having the bullet-shaped portion 117 is adopted as the swirling flow generating portion 110 (configuration of the second embodiment, shown as "E2" in Fig. 9).

[0055] 9, regardless of the taper angle ψ, when a configuration having the bullet-shaped portion 117 is adopted as the swirling flow generating portion 110 (E2), the flow rate Q at a certain upstream pressure P0 tends to be larger (i.e., the pressure loss in the swirling flow generating portion 110 is smaller) compared to when a configuration not having the bullet-shaped portion 117 is adopted as the swirling flow generating portion 110 (E1). Referring to this result, it can be said that by adopting a configuration having the bullet-shaped portion 117 as the swirling flow generating portion 110, the pressure drop on the downstream side of the vane 113 can be suppressed, the pressure in the throat portion 122 of the Venturi tube 120 can be reduced more effectively, and microbubbles can be generated more effectively.

[0056] 10 to 13 are explanatory diagrams showing the performance evaluation results of microbubble generation. Each figure shows a photograph showing the state of microbubble generation when a microbubble generator having the following configuration was operated. FIG. 10 shows the microbubble generation state by a microbubble generator of a comparative example that does not have a swirling flow generating section 110, FIG. 11 shows the microbubble generation state by a microbubble generator (see FIG. 2) in which the taper angle ψ of the Venturi tube 120 is 10 degrees, the vane angle θ of the swirling flow generating section 110 is 30 degrees, and there is no bullet-shaped section 117, FIG. 12 shows the microbubble generation state by a microbubble generator (see FIG. 4) in which the taper angle ψ of the Venturi tube 120 is 10 degrees, the vane angle θ of the swirling flow generating section 110 is 30 degrees, and there is a bullet-shaped section 117, and FIG. 13 shows the microbubble generation state by a microbubble generator (see FIG. 4) in which the taper angle ψ of the Venturi tube 120 is 14 degrees, the vane angle θ of the swirling flow generating section 110 is 30 degrees, and there is a bullet-shaped section 117. In each figure, the upper, middle, and lower rows show the microbubble generation conditions when the inner diameter d of the throat 122 of the Venturi tube 120 is 1.5 mm, 2 mm, and 3 mm, respectively. The flow rate was 9 L / min, the water pressure at the upstream end of the device was 0.15 MPa, and no air was supplied.

[0057] It can be seen that the microbubble generation state by the microbubble generator having the swirling flow generating part 110 (FIGS. 11 to 13) is higher in white turbidity and generates a larger amount of microbubbles than the microbubble generation state by the microbubble generator not having the swirling flow generating part 110 (FIG. 10). In addition, since a large amount of microbubbles is generated even when the taper angle ψ of the Venturi tube 120 is 10 degrees or more, it is recognized that the occurrence of separation of the fluid in the taper part 123 downstream of the throat part 122 of the Venturi tube 120 is suppressed. In reference to this result, it can be said that if the swirling flow generating part 110 is arranged on the upstream side of the Venturi tube 120, the pressure P1 of the throat part 122 of the Venturi tube 120 can be sufficiently reduced even when the taper angle ψ is 10 degrees or more, and as a result, microbubbles can be effectively generated.

[0058] D. Variations: The technology disclosed in this specification is not limited to the above-described embodiments, and can be modified in various forms without departing from the spirit of the invention. For example, the following modifications are also possible.

[0059] The configuration of the shower head 10 in the above embodiment is merely an example, and various modifications are possible. For example, the plate thickness t of the vane 113 and the distance L from the downstream end of the vane 113 to the upstream end of the Venturi tube 120 in the above embodiment may be changed. sw This is merely an example and various modifications are possible.

[0060] In the above embodiment, in at least one longitudinal section of the vane 113, the contour line of the downstream end of the vane 113 has a portion 115 bent at an acute angle, but the vane 113 does not necessarily have to have such a portion.

[0061] In the above embodiment, the wing body 112 having the vane 113 is used as the swirling flow generating section 110, but other configurations may be adopted for the swirling flow generating section 110.

[0062] In the microbubble generator 100 of the above embodiment, a configuration may be adopted in which air is supplied from the throat 122 of the Venturi tube 120. Even in such a configuration, by applying the technology disclosed in this specification, the pressure in the throat 122 of the Venturi tube 120 can be effectively reduced, the amount of air supplied from the throat 122 can be increased, and microbubbles can be effectively generated.

[0063] Although the microbubble generator 100 has been described in the above embodiment, the technology disclosed in this specification is not limited to the microbubble generator 100, but is generally applicable to fluid processing devices that perform some processing on a fluid. FIG. 14 is an explanatory diagram showing the configuration of a fluid mixing device 102 as a fluid processing device. The fluid mixing device 102 has a similar configuration to the microbubble generator 100 shown in FIG. 2, but is different in that an air supply pipe 230 is connected to the throat 122 of the Venturi tube 120. In the fluid mixing device 102, a process is performed in which a fluid (e.g., a first gas) supplied from the upstream side of the swirling flow generating section 110 is mixed with a fluid (e.g., a second gas) supplied to the throat 122 via the air supply pipe 230, and the mixed fluid is discharged from the Venturi tube 120 to the downstream side. Even in the fluid mixing device 102 having such a configuration, the swirling flow generating section 110 is disposed on the upstream side of the Venturi tube 120. Therefore, due to the presence of a relatively weak swirling flow imparted in the swirling flow generating section 110, even if the taper angle ψ of the Venturi tube 120 is made relatively large (for example, 10 degrees or more), separation of the fluid flow FL from the inner wall surface 124 in the downstream taper section 123 of the Venturi tube 120 can be suppressed, and the diffuser effect in the Venturi tube 120 can be increased to effectively reduce the pressure in the throat portion 122. As a result, mixing of the fluids can be effectively performed. [Explanation of symbols]

[0064] 10: shower head 11: head section 12: grip section 13: hose connection section 14: water outlet surface 15: water outlet hole 16: upstream water passage section 17: downstream water passage section 100: microbubble generator 102: fluid mixer 110: swirl flow generating section 111: tubular section 112: blade body 113: vane 114: surface 115: part 116: cylindrical section 117: bullet-shaped section 120: venturi tube 121: upstream tapered section 122: throat section 123: downstream tapered section 124: inner wall surface 230: air intake pipe

Claims

1. A fluid processing apparatus, A Venturi tube having a throat section, A swirling flow generating unit is positioned upstream of the Venturi tube and generates a swirling flow in the supplied fluid such that the ratio of the flow velocity v in the swirling direction to the flow velocity u in the axial direction at the throat (v / u) is less than 1. A fluid processing apparatus equipped with the following features.

2. A fluid apparatus according to claim 1, The swirling flow generating unit generates a swirling flow in the supplied fluid, wherein the ratio of the flow velocity V in the swirling direction to the flow velocity U in the axial direction in the swirling flow generating unit (V / U) is less than 1.

3. A fluid apparatus according to claim 1 or claim 2, The swirling flow generation unit is, Tubular part, A fluid apparatus comprising at least one vane housed within the tubular portion and having a surface set to be inclined with respect to the axial direction so as to generate the swirling flow.

4. A fluid apparatus according to claim 3, The vane is t ｍａｘ / D ｍｉｎ < 1 / 5 (however t ｍａｘ D is the maximum thickness of the vane, ｍｉｎ A fluid processing apparatus configured to satisfy the following relationship: (where is the minimum value of the inner diameter of the swirling flow generating section.)

5. A fluid apparatus according to claim 3, A fluid apparatus comprising, in at least one longitudinal section of the vane, the contour line of the downstream end of the vane has a portion that is sharply bent.

6. A fluid apparatus according to claim 3, The swirling flow generation unit is, A cylindrical portion located at the center of the swirling flow generating section and extending in the axial direction, A fluid processing apparatus having a bullet-shaped portion positioned downstream of the vane and the cylindrical portion, and which decreases in diameter toward the downstream side.

7. A fluid apparatus according to claim 3, The distance L from the downstream end of the vane to the upstream end of the venturi tube. ｓｗ D ｍｉｎ - greater than cotθ (where D ｍｉｎ is the minimum value of the inner diameter of the swirling flow generating section. ), Fluid processing apparatus.

8. A fluid apparatus according to claim 1, A fluid processing apparatus in which the taper angle ψ of the Venturi tube is 10 degrees or more.

9. A microbubble generator having the fluid processing apparatus described in claim 1.

10. A shower head comprising the microbubble generator described in claim 9.

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