Fine bubble supply device and aqueous solution supply device

Abstract

To provide a technique capable of increasing the amount of fine bubbles supplied to a bathtub.SOLUTION: A fine bubble supply device comprises: a circulation path that circulates water in a bathtub; an upstream pump provided in the circulation path; a downstream pump provided on a downstream side of the upstream pump in the circulation path; a gas introduction section provided on an upstream side of the downstream pump in the circulation path; a tank provided on a downstream side of the downstream pump in the circulation path; a fine bubble generation nozzle provided on a downstream side of the tank in the circulation path; and a control device. The control device is capable of executing a fine bubble supply operation in which the upstream pump and the downstream pump are driven to send water in the bathtub to the tank and to send the water in the tank to the bathtub through the fine bubble generation nozzle. During execution of the fine bubble supply operation, the pressure of the water flowing through the circulation path on the upstream side of the downstream pump is lower than the pressure of the gas introduced into the circulation path through the gas introduction section, and the pressure of the water flowing through the circulation path between the downstream pump and the tank is higher than the pressure of the gas introduced into the circulation path through the gas introduction section.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a fine bubble supplying device and an aqueous solution supplying device. [Background technology]

[0002] Patent Document 1 discloses a fine-bubble supply device including a circulation path for circulating water in a bathtub, a pump provided in the circulation path, a fine-bubble generating nozzle provided in the circulation path downstream of the pump, a gas inlet connected to a gas cartridge filled with a predetermined gas and introducing the gas filled in the gas cartridge into the fine-bubble generating nozzle, and a control device. The control device is configured to drive the pump to perform a fine-bubble supply operation for sending the water in the bathtub to the bathtub via the fine-bubble generating nozzle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-81360 Summary of the Invention [Problem to be solved by the invention]

[0004] One of the principles of microbubble generation is that water with dissolved gas is decompressed as it flows through a microbubble generating nozzle, causing the gas dissolved in the water to precipitate as microbubbles. According to this principle, the greater the amount of gas dissolved in the water flowing through the microbubble generating nozzle, the greater the amount of microbubbles that precipitate from the microbubble generating nozzle. In the microbubble supply device of Patent Document 1, gas is mixed into the water only after the water reaches the microbubble generating nozzle. Therefore, only a small amount of gas dissolves in the water flowing through the microbubble generating nozzle, which may result in a small amount of microbubbles precipitating from the microbubble generating nozzle. As a result, the amount of microbubbles supplied to the bathtub may be small. This specification provides a technology that can increase the amount of microbubbles supplied to the bathtub or the amount of gas dissolved in the water supplied to the bathtub. [Means for solving the problem]

[0005] In a first aspect of the present technology, a fine-bubble supply device may include a circulation path for circulating water in a bathtub, an upstream pump provided in the circulation path, a downstream pump provided in the circulation path downstream of the upstream pump, a gas inlet provided in the circulation path upstream of the downstream pump, a gas cartridge filled with a predetermined gas connected thereto, and the gas inlet provided to introduce the gas from the gas cartridge into the circulation path, a tank provided in the circulation path downstream of the downstream pump for dissolving the gas in the water, a fine-bubble generating nozzle provided in the circulation path downstream of the tank, and a control device. The control device may be configured to drive the upstream pump and the downstream pump to send the water in the bathtub to the tank and to perform a fine-bubble supply operation for sending the water in the tank to the bathtub through the fine-bubble generating nozzle. During the fine-bubble supply operation, the pressure of the water flowing through the circulation path upstream of the downstream pump may be lower than the pressure of the gas introduced into the circulation path via the gas inlet. The pressure of the water flowing through the circulation path between the downstream pump and the tank during the fine bubble supply operation may be higher than the pressure of the gas introduced into the circulation path through the gas introduction part.

[0006] According to the above configuration, a tank is provided downstream of the gas inlet in the circulation path, and a fine-bubble generating nozzle is provided downstream of the tank. Therefore, water mixed with gas passes through the tank and is then supplied to the fine-bubble generating nozzle. This increases the amount of gas dissolved in the water flowing through the fine-bubble generating nozzle, thereby increasing the amount of fine bubbles that precipitate in the fine-bubble generating nozzle. Furthermore, according to the above configuration, the water pressure at the location of the circulation path where the gas inlet is provided is lower than the pressure of the gas introduced into the circulation path via the gas inlet. Therefore, a relatively large amount of gas is introduced into the circulation path. This significantly increases the amount of gas dissolved in the water flowing through the fine-bubble generating nozzle, thereby significantly increasing the amount of fine bubbles that precipitate in the fine-bubble generating nozzle. Therefore, according to the above configuration, the amount of fine bubbles supplied to the bathtub can be increased.

[0007] In a second aspect of the present technology, in the first aspect, a pressure of the water flowing through the circulation path upstream of the upstream pump during the fine-bubble supply operation may be lower than atmospheric pressure. A pressure of the water flowing through the circulation path between the upstream pump and the tank during the fine-bubble supply operation may be higher than atmospheric pressure. The gas introduction part may be provided in the circulation path between the upstream pump and the downstream pump.

[0008] If the water pressure at the location of the circulation path where the gas inlet is provided is lower than atmospheric pressure, an excessively large amount of gas may be introduced into the circulation path. In this case, an excessively large amount of gas may be supplied to the downstream pump, causing the downstream pump to run idle. With the above configuration, the water pressure at the location of the circulation path where the gas inlet is provided is higher than atmospheric pressure, preventing an excessively large amount of gas from being introduced into the circulation path. This prevents an excessively large amount of gas from being supplied to the downstream pump, thereby preventing the downstream pump from running idle.

[0009] In a third aspect of the present technology, in the first or second aspect, the fine bubble supply device may further include an additional pump provided in the circulation path between the downstream pump and the tank.

[0010] According to the above configuration, the number of pumps that pump water toward the tank can be increased, thereby increasing the pressure of the water sent to the tank and increasing the solubility of gas in water. This increases the amount of gas dissolved in water, thereby further increasing the amount of gas dissolved in water flowing through the fine-bubble generating nozzle. This further increases the amount of fine bubbles that precipitate in the fine-bubble generating nozzle, thereby further increasing the amount of fine bubbles supplied to the bathtub.

[0011] In a fourth aspect of the present technology, in any one of the first to third aspects, the gas may be carbon dioxide gas.

[0012] It is known that immersing a user's body in water containing fine bubbles of carbon dioxide gas (a so-called carbonated bath) causes the carbon dioxide gas to be absorbed into the user's body, and the carbon dioxide gas absorbed into the body promotes blood flow. With the above configuration, the fine bubbles of carbon dioxide gas can be supplied to the bathtub using the fine bubble supply device, allowing the user to take a carbonated bath.

[0013] In a fifth aspect of the present technology, in any one of the first to fourth aspects, the microbubble supply device may further include a bubble splitting section that is provided downstream of the gas introduction section in the circulation path and splits the gas bubbles contained in the water.

[0014] Undissolved gas exists as bubbles in the water in the circulation path. If the gas bubbles are large, the surface area of ​​the bubbles (i.e., the interfacial area between the gas and water) per bubble volume (i.e., the amount of gas) becomes small, and the rate at which the gas dissolves in the water decreases. For this reason, the gas may not completely dissolve in the water, and the amount of gas dissolved in the water flowing through the circulation path may decrease. As a result, the amount of fine bubbles precipitated in the fine-bubble generating nozzle may become small. According to the above configuration, the bubble splitting section can split the gas bubbles and make them finer. This makes it possible to increase the surface area of ​​the bubbles (i.e., the interfacial area between the gas and water) per bubble volume (i.e., the amount of gas), and therefore the rate at which the gas dissolves in the water can be increased. This makes it possible to increase the amount of gas dissolved in the water flowing through the circulation path, and therefore the amount of fine bubbles precipitated in the fine-bubble generating nozzle.

[0015] According to a sixth aspect of the present technology, in the fifth aspect, the bubble breakup section may be provided downstream of the gas introduction section and upstream of the downstream pump in the circulation path.

[0016] If large bubbles flow into the downstream pump together with water, the downstream pump may temporarily idle, which may cause a temporary delay in the fine-bubble supply operation. Reducing the amount of gas introduced from the gas introduction section to the circulation path is one possible means of suppressing this. However, reducing the amount of gas introduced from the gas introduction section to the circulation path may reduce the amount of gas dissolved in the water flowing through the circulation path, which may result in a reduced amount of fine bubbles precipitated in the fine-bubble generating nozzle. In contrast, with the above-described configuration, the bubble breakup section disposed upstream of the downstream pump can break up and refine the gas bubbles. This prevents large bubbles from flowing into the downstream pump together with water, thereby preventing the downstream pump from temporarily idling and preventing a temporary delay in the fine-bubble supply operation. Therefore, the amount of gas introduced from the gas introduction section to the circulation path can be increased compared to a conventional configuration not equipped with a bubble breakup section. This increases the amount of gas dissolved in the water flowing through the circulation path, thereby increasing the amount of fine bubbles precipitated in the fine-bubble generating nozzle.

[0017] In a seventh aspect of the present technology, an aqueous solution supplying device may include a circulation path for circulating water in a bathtub, an upstream pump provided in the circulation path, a downstream pump provided in the circulation path downstream of the upstream pump, a gas inlet provided in the circulation path upstream of the downstream pump, a gas cartridge filled with a predetermined gas connected thereto, and the gas inlet provided to introduce the gas from the gas cartridge into the circulation path, a tank provided in the circulation path downstream of the downstream pump for dissolving the gas in the water, and a control device. The control device may be configured to drive the upstream pump and the downstream pump to send the water in the bathtub to the tank and to perform an aqueous solution supplying operation for sending the water in the tank to the bathtub. During the aqueous solution supplying operation, the pressure of the water flowing through the circulation path upstream of the downstream pump may be lower than the pressure of the gas introduced into the circulation path via the gas inlet. The pressure of the water flowing through the circulation path between the downstream pump and the tank during the aqueous solution supply operation may be higher than the pressure of the gas introduced into the circulation path via the gas introduction part.

[0018] In the aqueous solution supply device of Patent Document 1, gas is mixed into the water only when the water reaches the fine-bubble generating nozzle located immediately before the bathtub. Therefore, there is a risk that only a small amount of gas will be dissolved in the water supplied to the bathtub. In contrast, with the above configuration, a tank is provided upstream of the bathtub in the circulation path, and a gas inlet is provided upstream of the tank. Therefore, the water mixed with gas passes through the tank before being supplied to the bathtub. This increases the amount of gas dissolved in the water supplied to the bathtub. Furthermore, with the above configuration, the water pressure at the point in the circulation path where the gas inlet is provided is lower than the pressure of the gas introduced into the circulation path via the gas inlet. Therefore, a relatively large amount of gas is introduced into the circulation path. This significantly increases the amount of gas dissolved in the water supplied to the bathtub. [Brief explanation of the drawings]

[0019] [Figure 1]1 is a diagram schematically illustrating the configuration of a fine bubble supplying device 2 according to a first embodiment. [Figure 2] 3 is a diagram schematically illustrating the flow of water when a fine bubble supply operation is being performed in the fine bubble supply device 2 according to the first embodiment. FIG. [Figure 3] FIG. 10 is a diagram schematically illustrating the configuration of a fine bubble supplying device 2 according to a second embodiment. [Figure 4] FIG. 4 is an enlarged view of an area A in FIG. [Figure 5] FIG. 10 is a cross-sectional perspective view of a bubble breaking section 60 provided in a fine bubble supplying device 2 according to a second embodiment. [Figure 6] 10 is a diagram schematically illustrating another example of the bubble breakup section 60 provided in the fine bubble supplying device 2 according to the second embodiment. [Figure 7] 10 is a diagram schematically illustrating yet another example of the bubble breakup section 60 provided in the fine bubble supplying device 2 according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0020] Example 1 The fine bubble supplying device 2 shown in Fig. 1 is a device for supplying fine bubbles to a bathtub 100. The fine bubble supplying device 2 includes a circulation path 4, an upstream pump 6, a downstream pump 8, an additional pump 10, a gas introduction section 12, a tank 14, a circulation device 16, a control device 18, and a housing 20. The housing 20 accommodates a part of the circulation path 4, the upstream pump 6, the downstream pump 8, the additional pump 10, the gas introduction section 12, the tank 14, and the control device 18. The remainder of the circulation path 4 and the circulation device 16 are disposed outside the housing 20.

[0021] The circulation device 16 includes a suction passage 22 connected to the upstream end of the circulation passage 4, and a discharge passage 24 connected to the downstream end of the circulation passage 4. A fine-bubble generating nozzle 26 is provided in the discharge passage 24. The fine-bubble generating nozzle 26 is a so-called venturi nozzle, and reduces the pressure of water passing through the discharge passage 24.

[0022] The circulation path 4 includes a first water path 41, a second water path 42, a third water path 43, a fourth water path 44, and a fifth water path 45. The upstream end of the first water path 41 is connected to the suction path 22 of the circulation device 16. The downstream end of the first water path 41 is connected to the suction port of the upstream pump 6. The upstream end of the second water path 42 is connected to the discharge port of the upstream pump 6. The downstream end of the second water path 42 is connected to the suction port of the downstream pump 8. The upstream end of the third water path 43 is connected to the discharge port of the downstream pump 8. The downstream end of the third water path 43 is connected to the suction port of the additional pump 10. The upstream end of the fourth water path 44 is connected to the discharge port of the additional pump 10. The downstream end of the fourth water path 44 is connected to the tank water supply port 14a formed in the tank 14. The upstream end of the fifth water path 45 is connected to the tank drain port 14b formed in the tank 14. The downstream end of the fifth water passage 45 is connected to the discharge passage 24 of the circulation device 16 .

[0023] The upstream pump 6 sucks in water from the first water passage 41 and pumps it toward the second water passage 42. The upstream pump 6 is a self-priming pump that can suck in water from the upstream water passage (first water passage 41) even if the upstream water passage (first water passage 41) is not filled with water. The downstream pump 8 sucks in water from the second water passage 42 and pumps it toward the third water passage 43. The downstream pump 8 is a non-self-priming pump that cannot suck in water from the upstream water passage (second water passage 42) unless the upstream water passage (second water passage 42) is filled with water. The additional pump 10 sucks in water from the third water passage 43 and pumps it toward the fourth water passage 44. The additional pump 10 is a non-self-priming pump that cannot suck in water from the upstream water passage (third water passage 43) unless the upstream water passage (third water passage 43) is filled with water. The additional pump 10 is provided to further increase the pressure of the water pumped by the downstream pump 8 and send it to the tank 14 .

[0024] The gas introduction section 12 includes a regulator device 28, a gas introduction path 30, and a gas introduction valve 32. A gas cartridge 150 is detachably attached to the regulator device 28. The gas cartridge 150 of this embodiment is filled with carbon dioxide gas. The regulator device 28 adjusts the carbon dioxide gas filled in the gas cartridge 150 to a predetermined gas introduction pressure PG and supplies it to the gas introduction path 30. The gas introduction pressure PG is, for example, within a range of 30 kPa to 200 kPa, and is 60 kPa in this embodiment. It should be noted that the pressure values ​​described in this specification are differential pressures (gauge pressures) with respect to atmospheric pressure.

[0025] The upstream end of the gas introduction path 30 is connected to the regulator device 28. The downstream end of the gas introduction path 30 is connected to the second water path 42 of the circulation path 4. The gas introduction valve 32 is an electromagnetic valve that opens and closes the gas introduction path 30. Normally, the gas introduction valve 32 is closed, and the introduction of gas through the gas introduction path 30 is prohibited. When the gas introduction valve 32 is opened, the introduction of gas through the gas introduction path 30 is permitted. In this case, carbon dioxide gas filled in the gas cartridge 150 is adjusted to the gas introduction pressure PG in the regulator device 28 and then introduced into the second water path 42 through the gas introduction path 30.

[0026] Carbon dioxide gas flows into tank 14 along with the water flowing through circulation path 4. A portion of the carbon dioxide gas dissolves in the water flowing through circulation path 4 and then flows into tank 14. Meanwhile, the remainder of the carbon dioxide gas flows into tank 14 without dissolving in the water, and then separates from the water and accumulates in the upper part of tank 14. In this embodiment, the carbon dioxide gas that accumulates in the upper part of tank 14 is also referred to as retained gas. A gas-liquid dissolver 34 housed in tank 14 dissolves this retained gas in the water that has flowed into tank 14. Specifically, the gas-liquid dissolver 34 swirls the water that has flowed into tank 14 to generate a swirling flow. This swirling flow entrains the retained gas, causing it to be mixed again with the water. This dissolves the retained gas in the water.

[0027] The control device 18 includes a CPU, a ROM, and a RAM. The control device 18 controls the operation of each component of the fine bubble supply device 2 by the CPU executing processing in accordance with information stored in the ROM and RAM. The control device 18 is configured to be able to communicate with a remote control 200 that can be operated by a user. The user can instruct the control device 18 to start or end a fine bubble supply operation, which will be described later, via the remote control 200. The preliminary operation and fine bubble supply operation executed by the control device 18 will be described below.

[0028] (Preliminary run) The preliminary operation is performed prior to the fine-bubble supply operation. Specifically, the preliminary operation is initiated when the circulation device 16 is placed in the water (also referred to as bathtub water) stored in the bathtub 100 and the user issues a command to start the fine-bubble supply operation via the remote control 200. When the preliminary operation is initiated, the control device 18 drives the upstream pump 6, causing the upstream pump 6 to self-prime and introduce bathtub water into the circulation path 4. The control device 18 terminates the preliminary operation when a water flow sensor (not shown) installed in the fourth water path 44 detects a water flow (i.e., when at least the water path from the bathtub 100 to the additional pump 10 is filled with bathtub water). By performing the preliminary operation, the downstream pump 8 and the additional pump 10, which are non-self-priming pumps, are primed, enabling them to suck and pump water. Note that when the preliminary operation is terminated, the upstream pump 6 may remain running or may be stopped.

[0029] (Fine bubble supply operation) The microbubble supply operation begins after the preliminary operation ends. When the microbubble supply operation begins, the control device 18 drives the upstream pump 6, downstream pump 8, and additional pump 10 and opens the gas introduction valve 32. As a result, as shown in FIG. 2 , bath water is supplied to the tank 14 via the suction passage 22, the first water passage 41, the upstream pump 6, the second water passage 42, the downstream pump 8, the third water passage 43, the additional pump 10, and the fourth water passage 44. Carbon dioxide gas stored in the gas cartridge 150 is mixed with the bath water flowing through the second water passage 42 via the regulator device 28 and the gas introduction passage 30 and then supplied to the tank 14 together with the bath water. The carbon dioxide gas mixed with the bath water is pressurized and dissolved in the bath water as it flows through the circulation passage 4. After being supplied to the tank 14, the carbon dioxide gas is entrained in the swirling flow generated by the gas-liquid dissolver 34 and dissolved in the bath water. As a result, water with dissolved carbon dioxide gas (also called carbonated water) is stored inside the tank 14. The carbonated water stored inside the tank 14 is supplied from the tank 14 to the bathtub 100 via the fifth water passage 45 and the discharge passage 24. The carbonated water is depressurized to below atmospheric pressure when passing through the fine bubble generating nozzle 26 provided in the discharge passage 24, and is then pressurized to atmospheric pressure when discharged into the bathtub 100. As a result, fine bubbles of carbon dioxide gas are precipitated in the water supplied into the bathtub 100. In other words, fine bubbles of carbon dioxide gas are supplied to the bathtub 100. When a predetermined time (e.g., 30 minutes) has elapsed since the start of the fine bubble supply operation, the control device 18 closes the gas introduction valve 32 and stops the upstream pump 6, the downstream pump 8, and the additional pump 10, thereby ending the fine bubble supply operation. Alternatively, when the user issues an instruction to end the fine bubble supply operation via the remote control 200, the control device 18 closes the gas introduction valve 32 and stops the upstream pump 6, the downstream pump 8, and the additional pump 10, thereby ending the fine bubble supply operation. Note that, for the sake of explanation, arrows are used in Figure 2 to indicate the flow of water and the flow of carbon dioxide gas.

[0030] During the execution of the fine bubble supply operation, the pressure of the water flowing through the first water passage 41 becomes a first pressure P1 (for example, -20 kPa) lower than the atmospheric pressure. This is because the water in the bathtub 100, which is under a pressure approximately equal to the atmospheric pressure, is depressurized by the suction of the upstream pump 6 and flows into the first water passage 41. Also, during the execution of the fine bubble supply operation, the pressure of the water flowing through the second water passage 42 is a second pressure P2 (for example, 30 kPa) higher than the atmospheric pressure and lower than the aforementioned gas introduction pressure PG. In this embodiment, the pressure difference PG - P2 between the gas introduction pressure PG and the second pressure P2 is adjusted so as to be, for example, 50 kPa or less (that is, not excessively large). Further, during the execution of the fine bubble supply operation, the pressure of the water flowing through the third water passage 43 is a third pressure P3 (for example, 200 kPa) higher than the gas introduction pressure PG. Also, during the execution of the fine bubble supply operation, the pressure of the water flowing through the fourth water passage 44 is a fourth pressure P4 (for example, 350 kPa) higher than the third pressure P3. Therefore, during the execution of the fine bubble supply operation, P1 < 0 < P2 < PG < P3 < P4. This pressure magnitude relationship is realized by the control device 18 adjusting the outputs of the upstream pump 6, the downstream pump 8, and the additional pump 10. Note that the pressure of the water flowing through the fourth water passage 44 (the fourth pressure P4) can also be said to be the pressure in the tank 14 or the pressure of the water flowing through the fifth water passage 45.

[0031] (Features of Example 1) In this embodiment, the water pressure (second pressure P2) of the second water passage 42, in which the gas introduction part 12 is provided, of the circulation path 4 is lower than the pressure (gas introduction pressure PG) of the carbon dioxide gas introduced into the circulation path 4 through the gas introduction part 12. Therefore, a relatively large amount of carbon dioxide gas is introduced into the circulation path 4. The pressure of the water into which the carbon dioxide gas has been introduced is then increased by the downstream pump 8 and the additional pump 10. This increases the amount of carbon dioxide gas dissolved in the water flowing through the fine bubble generating nozzle 26, thereby increasing the amount of fine carbon dioxide gas bubbles precipitated in the fine bubble generating nozzle 26. Therefore, the amount of fine carbon dioxide gas bubbles supplied to the bathtub 100 can be increased. Furthermore, in this embodiment, the water pressure (second pressure P2) of the second water passage 42, in which the gas introduction part 12 is provided, of the circulation path 4 is higher than atmospheric pressure. Therefore, an excessively large amount of carbon dioxide gas is prevented from being introduced into the circulation path 4. This prevents an excessively large amount of carbon dioxide gas from being supplied to the downstream pump 8 and the additional pump 10, thereby preventing the downstream pump 8 and the additional pump 10 from running idle. Furthermore, in this embodiment, the pressure difference (PG-P2) between the pressure of the carbon dioxide gas introduced into the circulation path 4 (gas introduction pressure PG) and the pressure of the water in the second water path 42 (second pressure P2) is adjusted to be small. This also prevents an excessively large amount of carbon dioxide gas from being introduced into the circulation path 4, thereby preventing an excessively large amount of carbon dioxide gas from being supplied to the downstream pump 8 and the additional pump 10, and preventing the downstream pump 8 and the additional pump 10 from running idle. Furthermore, in this embodiment, the fine bubble supply device 2 can be used to supply fine bubbles of carbon dioxide gas to the bathtub 100, allowing the user to take a carbonated bath.

[0032] Example 2 As shown in Fig. 3, the fine bubble supplying device 2 of this embodiment is obtained by adding a bubble breakup section 60 to the fine bubble supplying device 2 of Example 1 (see Figs. 1 and 2). The bubble breakup section 60 is provided in the second water passage 42 of the circulation path 4, downstream of the gas inlet section 12 and upstream of the downstream pump 8. As shown in Fig. 4, the bubble breakup section 60 breaks up carbon dioxide bubbles B introduced from the gas inlet section 12 into circulation path 4, generating finer bubbles B'.

[0033] As shown in FIG. 5, the bubble breakup section 60 includes a casing 62 and multiple swirl flow generators 64. The interior space of the casing 62 functions as part of the second water passage 42 (see FIG. 3) of the circulation path 4. An inlet 66 through which water flows in is formed at the upstream end of the casing 62. An outlet 68 through which water flows out is formed at the downstream end of the casing 62. The multiple swirl flow generators 64 are arranged inside the casing 62 so as to be aligned in the direction of water flow. The multiple swirl flow generators 64 are densely arranged inside the casing 62, and their respective positions are fixed relative to the casing 62. Note that in FIG. 5, some of the multiple swirl flow generators 64 are omitted in order to show the interior space of the casing 62. Each of the multiple swirl flow generators 64 includes a shaft portion 70 extending from the upstream side to the downstream side, an outer peripheral portion 72 surrounding the radial outside of the shaft portion 70, and multiple blade portions 74 provided between the shaft portion 70 and the outer peripheral portion 72. The outer surface of the outer peripheral portion 72 has a shape that conforms to the inner surface of the casing 62. A swirl flow path 76 is formed between the shaft portion 70, the outer peripheral portion 72, and the multiple blade portions 74. When water flows through the second water passage 42 during the fine bubble supply operation, the water flows into the swirl flow path 76 of the swirl flow generator 64. The water flowing through the swirl flow path 76 generates a swirl flow in which the water flows spirally around the shaft portion 70. At this time, carbon dioxide bubbles contained in the water are broken up by the shear force caused by the swirl flow, becoming finer bubbles.

[0034] (Features of Example 2) (See FIGS. 1 and 3 ) When the gas introduction pressure PG in the regulator device 28 is increased and the amount of gas introduced from the gas introduction section 12 is increased, the carbon dioxide gas may form large bubbles immediately after introduction. If these large bubbles flow into the downstream pump 8 together with water, the downstream pump 8 may temporarily idle, which may temporarily disrupt the fine bubble supply operation. In this regard, the configuration of Example 2 (see FIG. 3 ) can break up and refine carbon dioxide gas bubbles using the bubble breakup section 60 disposed between the gas introduction section 12 and the downstream pump 8. This prevents large bubbles from flowing into the downstream pump 8 together with water, thereby preventing the downstream pump 8 from temporarily idling and temporarily disrupting the fine bubble supply operation. On the other hand, the configuration of Example 1 (see FIG. 1 ) does not include the bubble breakup section 60 and therefore does not have a means for breaking up large bubbles formed upstream of the downstream pump 8. For this reason, the only way to prevent the formation of large bubbles is to reduce the gas introduction pressure PG in the regulator device 28 and the amount of gas introduced from the gas introduction section 12. Therefore, compared to the configuration of Example 1 (i.e., a configuration not provided with the bubble-breaking section 60), the configuration of Example 2 (i.e., a configuration provided with the bubble-breaking section 60) makes it possible to increase the gas introduction pressure PG in the regulator device 28 and increase the amount of gas introduced from the gas introduction section 12. For example, the gas introduction pressure PG in Example 2 is set to a pressure within a range of 1.1 to 2.0 times the gas introduction pressure PG in Example 1. This increases the amount of carbon dioxide gas dissolved in the water flowing through the circulation path 4, thereby increasing the amount of fine carbon dioxide gas bubbles precipitated in the fine-bubble generating nozzle 26. As a result, the configuration of Example 2 (i.e., a configuration provided with the bubble-breaking section 60) makes it possible to shorten the time required to complete the fine-bubble supply operation compared to the configuration of Example 1 (i.e., a configuration not provided with the bubble-breaking section 60). The "time required to complete the fine bubble supply operation" here is specified as the time required, for example, to start the fine bubble supply operation with a predetermined amount (e.g., 100 L) of bath water stored in bathtub 100, and for the concentration of carbon dioxide gas dissolved in the bath water to reach a predetermined target concentration (e.g., 1000 ppm).The time required to complete the fine bubble supply operation is 30 minutes in the configuration of Example 1, whereas the time required to complete the fine bubble supply operation is reduced to 20 minutes in the configuration of Example 2. By reducing the time required to complete the fine bubble supply operation, the user's waiting time is reduced, improving the usability of the fine bubble supply device 2.

[0035] (See FIG. 4) Furthermore, according to the configuration of Example 2, carbon dioxide gas bubbles present in the water in the circulation path 4 break up in the bubble breakup section 60, which increases the surface area of ​​the bubbles (i.e., the interface area between the carbon dioxide gas and the water) per bubble volume (i.e., the amount of carbon dioxide gas). As a result, the rate at which carbon dioxide gas dissolves in the water flowing through the circulation path 4 increases. This also contributes to increasing the amount of carbon dioxide gas dissolved in the water flowing through the circulation path 4, and ultimately contributes to shortening the time required to complete the fine bubble supply operation.

[0036] (Variation) (See FIGS. 1 and 3) In the first and second embodiments, the downstream end of the gas introduction path 30 may be connected to the first water path 41. That is, the downstream end of the gas introduction path 30 may be connected to the circulation path 4 upstream of the upstream pump 6.

[0037] (See FIGS. 1 and 3) In the first and second embodiments, the fine bubble supplying device 2 may further include a pump other than the upstream pump 6, the downstream pump 8, and the additional pump 10. This pump may be provided in any of the first water passage 41, the second water passage 42, the third water passage 43, the fourth water passage 44, and the fifth water passage 45.

[0038] In the first and second embodiments, the fine bubble supplying device 2 does not necessarily have to include the additional pump 10 (see FIGS. 1 and 3).

[0039] (See FIGS. 1 and 3) In the first and second embodiments, instead of the gas cartridge 150, a gas cartridge filled with a gas other than carbon dioxide gas (e.g., nitrogen gas, hydrogen gas) may be attached to the regulator device 28. In this way, the fine bubble supply device 2 may supply fine bubbles of a gas other than carbon dioxide gas to the bathtub 100.

[0040] (See FIGS. 1 and 3.) In the first and second embodiments, the tank 14 may be provided with a water level sensor (e.g., an electrode rod) that detects the water level in the tank 14. In this case, the control device 18 may control the fine bubble supply device 2 based on the water level in the tank 14 detected by the water level sensor during the fine bubble supply operation. For example, the control device 18 may close the gas introduction valve 32 when the water level in the tank 14 falls below a predetermined lower threshold. This stops the introduction of carbon dioxide gas into the circulation path 4, and the water level in the tank 14 may rise as the carbon dioxide gas dissolves in the water in the tank 14. Thereafter, the control device 18 may open the gas introduction valve 32 when the water level in the tank 14 exceeds a predetermined upper threshold. This resumes the introduction of carbon dioxide gas into the circulation path 4, and the gaseous carbon dioxide gas accumulates in the tank 14, causing the water level in the tank 14 to drop. According to this example, the water level in the tank 14 is normally maintained between the lower threshold and the upper threshold. This prevents the water level in the tank 14 from becoming too low or too high.

[0041] (See Figures 1 and 3.) In Examples 1 and 2, the fine bubble generating nozzle 26 may not be provided in the discharge path 24 of the circulation device 16. As a result, compared to the configurations described in Examples 1 and 2, the amount of fine bubbles supplied to the bathtub 100 may be reduced, but high-concentration carbonated water may be supplied to the bathtub 100. The effects of a carbonated bath (e.g., promoting blood flow and relieving fatigue) are achieved by allowing the user to absorb carbon dioxide transdermally. Therefore, from the perspective of providing a carbonated bath, the carbon dioxide may be absorbed transdermally by the user via fine bubbles of carbon dioxide gas, or via carbonated water. The configuration of this modified example allows the user to absorb carbon dioxide transdermally mainly via carbonated water. In light of this, the fine bubble supply device 2 described in Examples 1 and 2 can also be called a "carbonated water supply device 2," and the fine bubble supply operation can also be called a "carbonated water supply operation."

[0042] (See Figures 1 and 3) In Example 2, the bubble breakup section 60 may be provided in any water channel of the circulation path 4, as long as it is downstream of the gas introduction section 12. For example, the bubble breakup section 60 may be provided in the third water channel 43, the fourth water channel 44, or the fifth water channel 45.

[0043] In the second embodiment, the bubble-breaking unit 60 may break up carbon dioxide bubbles in a manner different from that of the casing 62 and the multiple swirl flow generators 64 (see FIG. 5). As shown in FIG. 6, the bubble-breaking unit 60 may include an orthogonal plate 82 arranged perpendicular to the direction of water flow in the circulation path 4. In this example, carbon dioxide bubbles may flow with the water and break up by colliding with the upstream surface of the orthogonal plate 82. As shown in FIG. 7, the bubble-breaking unit 60 may include parallel plates 84 arranged parallel to the direction of water flow in the circulation path 4. In this example, carbon dioxide bubbles may flow with the water and break up by colliding with the upstream end of the parallel plate 84.

[0044] (Correspondence) The bathtub 100 is an example of a "bathtub." The circulation path 4 is an example of a "circulation path." The upstream pump 6 is an example of an "upstream pump." The downstream pump 8 is an example of a "downstream pump." The additional pump 10 is an example of an "additional pump." The gas cartridge 150 is an example of a "gas cartridge." The gas introduction unit 12 is an example of a "gas introduction unit." The tank 14 is an example of a "tank." The micro-bubble generating nozzle 26 is an example of a "micro-bubble generating nozzle." The control device 18 is an example of a "control device." The first water passage 41 and the second water passage 42 are examples of a "circulation path upstream of the downstream pump." The third water passage 43 and the fourth water passage 44 are examples of a "circulation path between the downstream pump and the tank." The first water passage 41 is an example of a "circulation path upstream of the upstream pump." The second water passage 42, the third water passage 43, and the fourth water passage 44 are examples of a "circulation path between the upstream pump and the tank." The second water passage 42 is an example of a "circulation passage between the upstream pump and the downstream pump." The bubble breakup section 60 is an example of a "bubble breakup section." The fine bubble supplying device 2 is an example of a "fine bubble supplying device." The carbonated water supplying device 2 is an example of an "aqueous solution supplying device."

[0045] The technical elements described in this specification or drawings exhibit technical utility either alone or in various combinations, and are not limited to the combinations set forth in the claims at the time of filing. Furthermore, the technologies illustrated in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of those objectives is itself technically useful. [Explanation of symbols]

[0046] 2: Fine bubble supply device, 4: Circulation path, 6: Upstream pump, 8: Downstream pump, 10: Additional pump, 12: Gas inlet, 14: Tank, 14a: Tank water supply port, 14b: Tank drain port, 16: Circulation device, 18: Control device, 20: Housing, 22: Suction path, 24: Discharge path, 26: Fine bubble generating nozzle, 28: Regulator device, 30: Gas inlet path, 32: Gas inlet valve , 34: Gas-liquid dissolver, 41: First water passage, 42: Second water passage, 43: Third water passage, 44: Fourth water passage, 45: Fifth water passage, 60: Bubble breakup section, 62: Casing, 64: Swirl flow generator, 66: Inlet, 68: Outlet, 70: Shaft, 72: Outer periphery, 74: Blade section, 76: Swirl flow path, 82: Orthogonal plate, 84: Parallel plate, 100: Bathtub, 150: Gas cartridge, 200: Remote control

Claims

1. A circulation path for circulating water in the bathtub; an upstream pump provided in the circulation path; a downstream pump provided downstream of the upstream pump in the circulation path; a gas introduction section that is provided in the circulation path upstream of the downstream pump, to which a gas cartridge filled with a predetermined gas is connected, and that introduces the gas filled in the gas cartridge into the circulation path; a tank provided downstream of the downstream pump in the circulation path, the tank dissolving the gas in the water; a fine bubble generating nozzle provided downstream of the tank in the circulation path; a control device; and the control device is configured to drive the upstream pump and the downstream pump to send the water in the bathtub to the tank and to execute a fine-bubble supply operation to send the water in the tank to the bathtub through the fine-bubble generating nozzle; a pressure of the water flowing through the circulation path upstream of the downstream pump during the fine bubble supply operation is lower than a pressure of the gas introduced into the circulation path through the gas introduction part; a pressure of the water flowing through the circulation path between the downstream pump and the tank during the fine bubble supply operation is higher than a pressure of the gas introduced into the circulation path through the gas inlet.

2. a pressure of the water flowing through the circulation path upstream of the upstream pump during the fine bubble supply operation is lower than atmospheric pressure; a pressure of the water flowing through the circulation path between the upstream pump and the tank during the fine bubble supply operation is higher than atmospheric pressure; The fine bubble supply device according to claim 1 , wherein the gas introduction section is provided in the circulation path between the upstream pump and the downstream pump.

3. The fine bubble supplying device according to claim 1 or 2, further comprising an additional pump provided in the circulation path between the downstream pump and the tank.

4. 3. The fine bubble supplying device according to claim 1, wherein the gas is carbon dioxide gas.

5. 3. The fine bubble supply device according to claim 1, further comprising a bubble breakup section provided downstream of the gas introduction section in the circulation path, for breaking up bubbles of the gas contained in the water.

6. The fine bubble supply device according to claim 5 , wherein the bubble breakup section is provided downstream of the gas introduction section and upstream of the downstream pump in the circulation path.

7. A circulation path for circulating water in the bathtub; an upstream pump provided in the circulation path; a downstream pump provided downstream of the upstream pump in the circulation path; a gas introduction section that is provided in the circulation path upstream of the downstream pump, to which a gas cartridge filled with a predetermined gas is connected, and that introduces the gas filled in the gas cartridge into the circulation path; a tank provided downstream of the downstream pump in the circulation path, the tank dissolving the gas in the water; a control device; and the control device is configured to drive the upstream pump and the downstream pump to send the water in the bathtub to the tank and to perform an aqueous solution supply operation to send the water in the tank to the bathtub; a pressure of the water flowing through the circulation path upstream of the downstream pump during the aqueous solution supply operation is lower than a pressure of the gas introduced into the circulation path through the gas inlet part; the pressure of the water flowing through the circulation path between the downstream pump and the tank during the aqueous solution supply operation is higher than the pressure of the gas introduced into the circulation path through the gas inlet.

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