Microbubble generator

Abstract

To provide a technique capable of appropriately suppressing adhesion of a droplet to at least one liquid level electrode among one or a plurality of liquid level electrodes.SOLUTION: A fine bubble generating device includes: a tank having a supply port and a discharge port; a mixed case for pressurizing and dissolving gas to a liquid; a supply path; an introduction path; a discharge path for discharging the liquid to a liquid tank; a fine bubble generating nozzle; one or a plurality of liquid level electrodes capable of detecting a liquid level in the tank; and an electrode cover provided so as to cover at least one liquid level electrode among the liquid level electrodes. The mixed case is provided with an outflow part. The liquid supplied to the supply port is introduced to the inside of the mixed case through the introduction path, is made to outflow to the outside of the mixed case from the outflow part, and thereby is stored in the tank. When the electrode cover is viewed in an extension direction of at least the one liquid level electrode among the one or the plurality of liquid level electrodes, the electrode cover covers the whole circumference of the liquid level electrode.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] This specification relates to a fine bubble generator.

Background Art

[0002] Patent Document 1 discloses a fine bubble generator including a tank having a supply port and a discharge port, a target member accommodated in the tank and having a through hole, a supply passage for supplying the liquid to the supply port, a discharge passage for discharging the liquid stored in the tank from the discharge port to a liquid tank, a fine bubble generation nozzle provided in the discharge passage for generating fine bubbles by decompressing the liquid in which the gas is pressurized and dissolved, one or a plurality of liquid level electrodes extending in the vertical direction inside the tank and outside the target member and capable of detecting whether the liquid level in the tank is equal to or higher than a predetermined liquid level, and an electrode cover provided so as to cover at least one of the one or a plurality of liquid level electrodes. The liquid supplied from the supply passage to the supply port collides with the target member and is configured to be stored in the tank through the through hole or outside the target member. When the electrode cover is viewed along the extending direction of at least one of the one or a plurality of liquid level electrodes, the electrode cover does not cover the entire circumference of at least one of the one or a plurality of liquid level electrodes.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a fine bubble generator, gas contained in the liquid in the tank rises in the liquid, and foam is generated on the liquid surface. Therefore, due to the rupture of the foam or the like, liquid droplets may scatter above the liquid surface. When the liquid droplets scattered from the liquid surface adhere to the liquid level electrode, there is a possibility that the liquid level electrode becomes sticky. If the liquid level electrode becomes sticky, there is a risk of erroneously detecting the liquid level of the tank. For this reason, in the fine bubble generator of Patent Document 1, in order to suppress the adhesion of the liquid droplets scattered from the liquid surface to the liquid level electrode, an electrode cover that covers at least one of the one or more liquid level electrodes is provided. However, in the electrode cover of Patent Document 1, it is impossible to suppress the adhesion of the liquid droplets scattered from the liquid surface to the liquid level electrode in a portion of the entire circumference of at least one of the one or more liquid level electrodes that is not covered by the electrode cover. Therefore, it is not possible to appropriately suppress the adhesion of the liquid droplets to at least one of the one or more liquid level electrodes. This specification provides a technique capable of appropriately suppressing the adhesion of liquid droplets to at least one of the one or more liquid level electrodes.

Means for Solving the Problems

[0005] The microbubble generator disclosed in this specification includes a tank having a supply port and a discharge port, a mixing case housed in the tank for pressurizing and dissolving the gas in the tank into the liquid flowing into the interior, a supply path for supplying the liquid to the supply port, an introduction path for introducing the liquid supplied to the supply port into the interior of the mixing case, a discharge path for discharging the liquid stored in the tank from the discharge port to a liquid tank, a microbubble generation nozzle provided in the discharge path for generating microbubbles by decompressing the liquid in which the gas is pressurized and dissolved, one or more liquid level electrodes extending vertically inside the tank and outside the mixing case for detecting whether the liquid level in the tank is equal to or higher than a predetermined liquid level, and an electrode cover provided so as to cover at least one of the one or more liquid level electrodes. The mixing case is provided with an outflow portion through which the liquid flows out. The liquid supplied from the supply path to the supply port is introduced into the interior of the mixing case through the introduction path, and is configured to be stored in the tank by flowing out from the outflow portion to the outside of the mixing case. When the electrode cover is viewed along the extending direction of at least one of the one or more liquid level electrodes among the one or more liquid level electrodes, the electrode cover covers the entire circumference of at least one of the one or more liquid level electrodes.

[0006] According to the above configuration, the electrode cover can suppress droplets scattered from the liquid surface from adhering to the liquid level electrode at the entire circumference of at least one of the one or more liquid level electrodes. Therefore, the adhesion of droplets to at least one of the one or more liquid level electrodes can be appropriately suppressed.

[0007] In one or more embodiments, the microbubble generator may further include a pressure pump provided in the supply path, a gas introduction mechanism capable of introducing gas into the tank, and a control device. The control device drives the pressure pump to pressurize and supply the liquid from the supply path to the supply port, and supplies the liquid in which the gas is pressurized and dissolved from the discharge port to the liquid tank through the discharge path, and performs a pressurized liquid supply operation. By operating the gas introduction mechanism, a gas introduction operation for introducing the gas into the tank may be configured to be executable, including a microbubble generation operation. When the lowest liquid level among the predetermined liquid levels detected by the one or more liquid level electrodes is defined as the lower limit liquid level, in the microbubble generation operation, if it is detected that the liquid level in the tank is lower than the lower limit liquid level during the execution of the gas introduction operation, the control device may be configured to stop the gas introduction operation and execute only the pressurized liquid supply operation to raise the liquid level in the tank. The lower end of the electrode cover may be located at a position lower than the lower limit liquid level.

[0008] When the lower end of the electrode cover is located at a position lower than the liquid level in the tank, the electrode cover suppresses the gas contained in the liquid in the tank from rising in the liquid and entering the inside of the electrode cover. In this case, inside the electrode cover, the generation of foam on the liquid surface is suppressed, and the scattering of liquid droplets upward from the liquid surface is suppressed. According to the above configuration, during the execution of the microbubble generation operation, the lower end of the electrode cover is always located at a position lower than the liquid level in the tank. Therefore, during the execution of the microbubble generation operation, inside the electrode cover, the generation of foam on the liquid surface is always suppressed, and the scattering of liquid droplets upward from the liquid surface is always suppressed. Therefore, according to the above configuration, the adhesion of liquid droplets to at least one of the one or more liquid level electrodes can be more appropriately suppressed. In this specification, "inside the electrode cover" means the side covering the liquid level electrode of the electrode cover.

[0009] In one or more embodiments, the one or more liquid level electrodes may include a first liquid level electrode capable of detecting whether the liquid level in the tank is equal to or higher than a first liquid level, and a second liquid level electrode capable of detecting whether the liquid level in the tank is equal to or higher than a second liquid level that is higher than the first liquid level. The lower limit liquid level may be the first liquid level. In the microbubble generation operation, when it is detected that the liquid level in the tank is equal to or higher than the second liquid level during the stop of the gas introduction operation, the control device may be configured to start the gas introduction operation to lower the liquid level in the tank.

[0010] According to the above configuration, the control device controls the operation of the gas introduction mechanism using the first liquid level electrode and the second liquid level electrode so that the liquid level of the tank changes between the first liquid level and the second liquid level. And the lower end of the electrode cover covering at least one of the one or more liquid level electrodes is located at a position lower than the first liquid level. According to the above configuration, in a microbubble generation device that controls the liquid level of a tank using two liquid level electrodes, the scattering of liquid droplets inside the electrode cover is always suppressed. For this reason, in a microbubble generation device that controls the liquid level of a tank using two liquid level electrodes, the adhesion of liquid droplets to at least one of the one or more liquid level electrodes can be appropriately suppressed.

[0011] In one or more embodiments, the electrode cover may be provided so as to cover the second liquid level electrode among the one or more liquid level electrodes.

[0012] When the control device controls the operation of the gas introduction mechanism so that the liquid level of the tank changes between the first liquid level and the second liquid level, since the first liquid level electrode is frequently immersed in the liquid, scale is relatively unlikely to occur on the first liquid level electrode. On the other hand, since the second liquid level electrode is hardly immersed in the liquid, scale is relatively likely to occur on the second liquid level electrode. According to the above configuration, the electrode cover is provided so as to cover the second liquid level electrode. For this reason, the adhesion of liquid droplets to the second liquid level electrode where scale is relatively likely to occur can be appropriately suppressed.

[0013] In one or more embodiments, the one or more liquid level electrodes may include only a third liquid level electrode capable of detecting whether the liquid level in the tank is equal to or higher than a third liquid level. The electrode cover may be provided to cover the third liquid level electrode. The lower limit liquid level may be the third liquid level. When the control device detects that the liquid level in the tank is lower than the lower limit liquid level and stops the gas introduction operation during the microbubble generation operation, the control device maintains the state in which the gas introduction operation is stopped until a predetermined time elapses after stopping the gas introduction operation, and may be configured to start the gas introduction operation after the elapse of the predetermined time.

[0014] According to the above configuration, the control device controls the operation of the gas introduction mechanism using the third liquid level electrode so that the liquid level of the tank is maintained at or above the third liquid level. And the lower end of the electrode cover covering at least one of the one or more liquid level electrodes is located at a position lower than the third liquid level. According to the above configuration, in the microbubble generator that controls the liquid level of the tank using one liquid level electrode, the scattering of droplets inside the electrode cover is always suppressed. For this reason, in the microbubble generator that controls the liquid level of the tank using one liquid level electrode, the adhesion of droplets to at least one of the one or more liquid level electrodes can be appropriately suppressed.

[0015] In one or more embodiments, the third liquid level may be located at a position higher than the lower end of the mixing case. The lower end of the electrode cover may be located at a position lower than the lower end of the mixing case.

[0016] The liquid supplied to the tank is stored along the shape of the outer surface of the mixing case and the shape of the inner surface of the tank. For this reason, the horizontal cross-sectional area of the liquid stored in the tank is relatively large at a position lower than the lower end of the mixing case and relatively small at a position higher than the lower end of the mixing case. Therefore, the amount per unit area of the gas rising in the liquid is relatively small at a position lower than the lower end of the mixing case and relatively large at a position higher than the lower end of the mixing case. According to the above configuration, the electrode cover extends to a position where the amount per unit area of the gas rising in the liquid is relatively small. For this reason, the electrode cover can further suppress the gas contained in the liquid in the tank from rising in the liquid and entering the inside of the electrode cover.

[0017] In one or more embodiments, when the control device executes the gas introduction operation during the pressurized liquid supply operation in the microbubble generation operation, at the start of the gas introduction operation, the pressurized liquid supply operation may be interrupted, and at the stop of the gas introduction operation, the interrupted pressurized liquid supply operation may be restarted.

[0018] When the pressurized liquid supply operation is not interrupted when the gas introduction operation is executed, it is necessary to adjust the amount of gas supplied to the tank in the gas introduction operation so that it exceeds the amount of gas consumed from the tank in the pressurized liquid supply operation, which may complicate the process. According to the above configuration, since the pressurized liquid supply operation is interrupted when the gas introduction operation is executed, there is no need to adjust the amount of gas supplied to the tank in the gas introduction operation and the amount of gas consumed from the tank in the pressurized liquid supply operation, and the process can be simplified.

[0019] In one or more embodiments, when the control device executes the gas introduction operation during the pressurized liquid supply operation in the microbubble generation operation, the control device may be configured to execute the gas introduction operation without interrupting the pressurized liquid supply operation.

[0020] When interrupting the pressurized liquid supply operation to execute the gas introduction operation, the fine bubbles generated in the liquid in the liquid tank during the pressurized liquid supply operation may disappear during the execution of the gas introduction operation, and it may not be possible to continuously and stably generate fine bubbles in the liquid in the liquid tank. According to the above configuration, it is not necessary to interrupt the pressurized liquid supply operation to execute the gas introduction operation, and the pressurized liquid supply operation can be continuously executed. According to the above configuration, fine bubbles can be continuously and stably generated in the liquid in the liquid tank.

[0021] In one or more embodiments, the electrode cover may be integrally formed seamlessly with a part of the mixing case.

[0022] In the manufacturing process of the fine bubble generator, it may be desired to reduce the number of parts. According to the above configuration, the number of parts can be reduced compared to the case where the electrode cover and the mixing case are provided separately.

[0023] In one or more embodiments, the liquid may be water. The liquid tank may be a bathtub used by a user for bathing.

[0024] According to the above configuration, in a fine bubble generator that generates fine bubbles in the water of a bathtub used by a user for bathing, the adhesion of liquid droplets to at least one of the one or more liquid level electrodes can be appropriately suppressed.

Brief Description of the Drawings

[0025]

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Embodiments for Carrying Out the Invention

[0026] (Example) As shown in FIG. 1, the hot water device 2 of this example includes a heat source unit 10, an air pressurization and dissolution unit 50, a bathtub adapter 132, and a control device 150. The hot water device 2 can heat the water supplied from a water supply source 200 such as a water pipe, and supply the heated water to a faucet 250 installed in a kitchen or the like, or a bathtub 130 installed in a bathroom at a desired temperature. Further, the hot water device 2 can generate fine bubbles in the water of the bathtub 130 used by the user for bathing.

[0027] (Configuration of the heat source unit 10) The heat source unit 10 includes a first heat source machine 12, a second heat source machine 14, a water supply path 16, a hot water outlet path 18, a bypass path 20, a bypass servo 22, a pouring path 24, a pouring valve 26, a water volume sensor 28, a circulation forward path 30, a circulation return path 32, a bathtub circulation pump 34, and a water flow switch 36.

[0028] The upstream end of the water supply path 16 is connected to the water supply source 200, and the downstream end of the water supply path 16 is connected to the first heat source machine 12. Also, the upstream end of the hot water outlet path 18 is connected to the first heat source machine 12, and the downstream end of the hot water outlet path 18 is connected to the faucet 250. The first heat source machine 12 is, for example, a combustion heat source machine that heats water by burning gas. The first heat source machine 12 heats the water flowing in from the water supply path 16 and sends out the heated water to the hot water outlet path 18.

[0029] The upstream end of the bypass passage 20 is connected to the water supply passage 16, and the downstream end of the bypass passage 20 is connected to the hot water outlet passage 18. The bypass servo 22 is provided at the location where the bypass passage 20 connects to the water supply passage 16. The bypass servo 22 can adjust the ratio of the flow rate of water flowing from the water supply passage 16 through the first heat source machine 12 to the hot water outlet passage 18 and the flow rate of water flowing from the water supply passage 16 through the bypass passage 20 to the hot water outlet passage 18 by adjusting the opening degree of the built-in valve element. By adjusting the opening degree of the bypass servo 22, hot water flowing in from the first heat source machine 12 and cold water flowing in from the bypass passage 20 are mixed at a desired ratio in the hot water outlet passage 18 on the downstream side of the connection location of the bypass passage 20, and water adjusted to a desired temperature is supplied. A hot water outlet thermistor 18a for detecting the temperature of the water in the hot water outlet passage 18 is provided in the hot water outlet passage 18 on the downstream side of the connection location of the bypass passage 20.

[0030] The upstream end of the pouring passage 24 is connected to the hot water outlet passage 18 on the downstream side of the connection location of the bypass passage 20, and the downstream end of the pouring passage 24 is connected to the circulation return passage 32. The pouring valve 26 is provided in the pouring passage 24 and opens and closes the pouring passage 24. The pouring valve 26 is normally in a closed state. The water volume sensor 28 is provided in the pouring passage 24 and detects the water volume of the water flowing through the pouring passage 24.

[0031] The upstream end of the circulation return passage 32 is connected to the heat source return passage 60 (details will be described later) of the air pressurization and dissolution unit 50, and the downstream end of the circulation return passage 32 is connected to the second heat source machine 14. Also, the upstream end of the circulation forward passage 30 is connected to the second heat source machine 14, and the downstream end of the circulation forward passage 30 is connected to the heat source forward passage 68 (details will be described later) of the air pressurization and dissolution unit 50. The second heat source machine 14 is, for example, a combustion heat source machine that heats water by gas combustion. The second heat source machine 14 heats the water flowing in from the circulation return passage 32 and sends the heated water out to the circulation forward passage 30. A circulation return thermistor 32a for detecting the temperature of the water in the circulation return passage 32 is provided near the upstream end of the circulation return passage 32. A circulation forward thermistor 30a for detecting the temperature of the water in the circulation forward passage 30 is provided near the downstream end of the circulation forward passage 30.

[0032] The bathtub circulation pump 34 is provided in the circulation return path 32 on the downstream side of the connection point of the hot water supply path 24, and sends out the water in the circulation return path 32 toward the second heat source unit 14. The water flow switch 36 is provided between the bathtub circulation pump 34 and the second heat source unit 14 in the circulation return path 32, and detects whether water is flowing in the circulation return path 32.

[0033] (Configuration of the air pressurization dissolution unit 50) The air pressurization dissolution unit 50 includes a tank 52, a heat source return path 60, a heat source forward path 68, a tank return path 74, a tank forward path 64, a communication path 66, a first three-way valve 80, a second three-way valve 82, a check valve 84, a tank water supply valve 86, a first pressurization pump 88, a second pressurization pump 90, a tank circulation path 92, a tank circulation pump 94, and a gas introduction mechanism 96.

[0034] (Configuration of the tank 52) The tank 52 can store water inside. Further, the tank 52 is used to pressurize and dissolve air in water to generate air-dissolved water.

[0035] As shown in FIG. 2, the tank 52 includes a tank upper part 520 and a tank lower part 522. The tank upper part 520 includes an electrode installation part 540, a first water supply port 74a, and a second water supply port 74b. The tank lower part 522 includes a case installation part 550, a drain port 64a, and a circulation opening 92a (see FIG. 3). The tank upper part 520 and the tank lower part 522 are fixed to each other by screws (not shown). The tank upper part 520 and the tank lower part 522 have an inner surface in a substantially cylindrical shape centered on an axis A along the vertical direction. And inside the tank 52, a mixing case 4 is accommodated. The mixing case 4 includes a case main body 40, a stirring part 42, a case lid 44, and an introduction pipe 46. Also, an electrode unit 54 is installed in the electrode installation part 540.

[0036] As shown in FIG. 3, the drain port 64a and the circulation opening 92a are provided on the lower surface of the lower tank portion 522 and open downward. Therefore, the water stored in the tank 52 is configured to be guided to the drain port 64a and the circulation opening 92a along the inner surface of the tank 52. In the present embodiment, when the lower tank portion 522 is viewed from above along the axis A, the drain port 64a and the circulation opening 92a are arranged at positions that do not overlap the axis A, respectively.

[0037] As shown in FIG. 4, when the lower tank portion 522 and the case main body 40 are viewed from above along the axis A, the drain port 64a (see FIG. 3) is arranged at a position hidden by the case main body 40. Further, when the lower tank portion 522 and the case main body 40 are viewed from above along the axis A, a part of the circulation opening 92a is arranged between the inner surface of the lower tank portion 522 and the outer surface of the first side wall portion 402 described later.

[0038] (Configuration of the case main body 40) As shown in FIG. 2, the case main body 40 includes a substantially disk-shaped first bottom plate portion 400 that extends horizontally, a first side wall portion 402 that extends upward from the peripheral edge of the first bottom plate portion 400, a plurality of outflow portions 404 formed by notching the upper end portion of the first side wall portion 402, and a plate-like member 406 and a plurality of mounting members 408 provided on the first side wall portion 402. In the present embodiment, the first bottom plate portion 400, the first side wall portion 402, the plate-like member 406, and the plurality of mounting members 408 are integrally formed without joints. Further, the first side wall portion 402 is formed in a substantially cylindrical shape centered on the axis A.

[0039] As shown in FIG. 4, the plate-like member 406 and the plurality of mounting members 408 are in contact with the case installation portion 550 of the lower tank portion 522 from above. Therefore, the case main body 40 is supported by the lower tank portion 522 via the plate-like member 406 and the plurality of mounting members 408.

[0040] In this embodiment, four outflow portions 404 are provided. Therefore, in this embodiment, the plurality of outflow portions 404 may be distinguished as a first outflow portion 404a, a second outflow portion 404b, a third outflow portion 404c, and a fourth outflow portion 404d.

[0041] The plurality of mounting members 408 are provided at predetermined angular intervals along the circumferential direction of the axis A. In this embodiment, three mounting members 408 are provided. Therefore, in this embodiment, the plurality of mounting members 408 may be distinguished as a first mounting member 408a, a second mounting member 408b, and a third mounting member 408c. The first mounting member 408a, the second mounting member 408b, and the third mounting member 408c are provided at 90° intervals along the circumferential direction of the axis A.

[0042] The plate-like member 406 is a flat plate having a substantially fan shape centered on the axis A. The plate-like member 406 is provided along the horizontal direction. The plate-like member 406 is provided within a predetermined angular range (for example, within an angular range of 70°) of the entire circumference of the first side wall portion 402 along the circumferential direction of the axis A. The plate-like member 406 protrudes radially outward from the outer surface of the first side wall portion 402 toward the axis A. Further, when the case body 40 is viewed from above along the axis A, the portion of the first side wall portion 402 where the plate-like member 406 is provided overlaps with all of the portion of the first side wall portion 402 where the first outflow portion 404a is provided. Further, when the case body 40 is viewed from above along the axis A, the distance in the circumferential direction of the axis A from the centroid of the plate-like member 406 to the centroid of the first outflow portion 404a is smaller than the distance in the circumferential direction of the axis A from the centroid of the plate-like member 406 to the centroid of the drain port 64a and is also smaller than the distance in the circumferential direction of the axis A from the centroid of the plate-like member 406 to the centroid of the circulation opening 92a.

[0043] As shown in FIG. 5, the plate-shaped member 406 is disposed below the first outflow portion 404a and above the drain port 64a and the circulation opening 92a. Further, the vertical distance from the plate-shaped member 406 to the first outflow portion 404a is smaller than the vertical distance from the plate-shaped member 406 to the drain port 64a and smaller than the vertical distance from the plate-shaped member 406 to the circulation opening 92a.

[0044] (Configuration of the stirring unit 42) As shown in FIG. 2, the stirring unit 42 includes a substantially disk-shaped second bottom plate portion 420 that extends horizontally, a second side wall portion 422 that extends upward from the peripheral edge of the second bottom plate portion 420, an insertion tube 424 and a fitting member 426 provided along the tangential direction of the second side wall portion 422, and a flange portion 428 that protrudes radially outward of the second side wall portion 422 at the upper portion of the second side wall portion 422. In this embodiment, the second bottom plate portion 420, the second side wall portion 422, the insertion tube 424, the fitting member 426, and the flange portion 428 are integrally formed without joints. Further, the second side wall portion 422 is formed in a substantially cylindrical shape centered on the axis A.

[0045] As shown in FIG. 5, the flange portion 428 is in contact with the upper end portion of the first side wall portion 402 of the case body 40 from above. For this reason, the stirring unit 42 is supported by the case body 40 via the flange portion 428. In a state where the stirring unit 42 is supported by the case body 40, the insertion tube 424 is fitted into a part of the fourth outflow portion 404d of the case body 40, and the fitting member 426 is fitted into a part of the first outflow portion 404a.

[0046] The stirring unit 42 further includes a jet outlet 425 formed in the second bottom plate portion 420. The second bottom plate portion 420 is disposed at a position spaced apart from the first bottom plate portion 400 of the case body 40 in the vertical direction. Further, the outer diameter of the second side wall portion 422 is smaller than the inner diameter of the first side wall portion 402 of the case body 40. Accordingly, a gap communicating the jet outlet 425 with the plurality of outflow portions 404 is provided between the stirring unit 42 and the case body 40.

[0047] (Configuration of the case lid 44) As shown in FIG. 2, the case lid 44 includes a substantially disc-shaped upper plate portion 440 that extends horizontally, a diameter-expanded portion 442 that is connected to the peripheral edge portion of the upper plate portion 440 and expands radially outward in the diameter direction of the axis A as it goes downward, a side plate portion 444 that extends downward from the lower end of the diameter-expanded portion 442, and an electrode cover 446 that is provided on the side plate portion 444 and extends in the vertical direction. In this embodiment, the upper plate portion 440, the diameter-expanded portion 442, the side plate portion 444, and the electrode cover 446 are integrally formed without joints. The electrode cover 446 is formed in a shape along the inner surfaces of the upper part 520 and the lower part 522 of the tank. Further, the upper plate portion 440 is provided with communication air holes (not shown).

[0048] As shown in FIG. 5, the case lid 44 is provided so as to cover the upper part of the case body 40 and the stirring portion 42. The space between the case lid 44 and the stirring portion 42 is sealed by a seal member (not shown). Therefore, the case lid 44 suppresses the water introduced into the stirring portion 42 from flowing out between the case lid 44 and the stirring portion 42 to the outside of the mixing case 4. Further, the case lid 44 suppresses the water from splashing above the tank 52 when water flows out from the plurality of outflow portions 404 of the case body 40.

[0049] (Configuration of the introduction pipe 46) The introduction pipe 46 is attached to the stirring portion 42 by being inserted into the insertion pipe 424 of the stirring portion 42. The introduction pipe 46 is provided so as to communicate the first water supply port 74a and the second water supply port 74b of the upper part 520 of the tank with the inside of the stirring portion 42. Therefore, the introduction pipe 46 can introduce the water supplied to the first water supply port 74a and the second water supply port 74b of the upper part 520 of the tank into the inside of the stirring portion 42.

[0050] (Configuration of the electrode unit 54) As shown in FIG. 2, the electrode unit 54 includes a high water level electrode 54a, a low water level electrode 54b, and a ground electrode 54c. The high water level electrode 54a, the low water level electrode 54b, and the ground electrode 54c extend vertically inside the tank 52 and outside the mixing case 4. When the high water level electrode 54a and the low water level electrode 54b come into contact with the water surface stored in the tank 52, a current flows between them and outputs an ON signal to the control device 150. That is, each of the high water level electrode 54a and the low water level electrode 54b is configured to be able to detect whether the water level in the tank 52 is equal to or higher than a predetermined water level. Hereinafter, the water level in the tank 52 detected by the low water level electrode 54b may be referred to as the "first water level". The water level in the tank 52 detected by the high water level electrode 54a may be referred to as the "second water level". The lower end of the high water level electrode 54a is at a position higher than the lower end of the low water level electrode 54b. Therefore, the second water level is higher than the first water level.

[0051] As shown in FIG. 6, the high water level electrode 54a is covered by an electrode cover 446. On the other hand, the low water level electrode 54b and the ground electrode 54c are not covered by the electrode cover 446. The lower end of the electrode cover 446 is at a position lower than the lower ends of the high water level electrode 54a, the low water level electrode 54b, and the ground electrode 54c. Also, the lower end of the electrode cover 446 is at a position lower than the lower end of the mixing case 4.

[0052] As shown in FIG. 7, when the electrode cover 446 is viewed from below, the electrode cover 446 covers the entire circumference of the high water level electrode 54a.

[0053] (Flow of water in the tank 52) As shown in FIG. 5, water supplied from the first water supply port 74a and the second water supply port 74b is introduced into the inside of the agitator 42 through the introduction pipe 46. The water introduced into the inside of the agitator 42 flows downward while swirling in a spiral shape inside the agitator 42. When the water swirls inside the agitator 42, a large negative pressure is generated near the center of the agitator 42. Therefore, the air that has accumulated at the top of the tank 52 is taken into the inside of the agitator 42 through the air communication hole (not shown) of the case lid 44. The air taken into the inside of the agitator 42 is caught in the water swirling inside the agitator 42. As a result, the air is dissolved in the water, and air-dissolved water is generated. The air-dissolved water generated inside the agitator 42 is ejected from the ejection port 425 toward the first bottom plate portion 400 of the case body 40. The air-dissolved water ejected from the ejection port 425 collides with the first bottom plate portion 400, changes direction, flows upward through the gap formed between the second side wall portion 422 and the first side wall portion 402, and flows out of the mixing case 4 from the multiple outlet portions 404 of the case main body 40. The air-dissolved water that flows out from the multiple outlet portions 404 flows downward through the gap formed between the inner surface of the tank 52 and the first side wall portion 402, and is stored in the tank 52. Note that the solid arrows in FIG. 5 indicate the flow of water.

[0054] As shown in FIG. 8, the air-dissolved water flowing out of the plurality of outlets 404 collides with the plate-shaped member 406 when flowing downward through the gap formed between the inner surface of the tank 52 and the first side wall 402. The air-dissolved water that collides with the plate-shaped member 406 changes direction so that it flows horizontally along the plate-shaped member 406. When the plate-shaped member 406 changes direction of the air-dissolved water, the air-dissolved water is decelerated. Therefore, if undissolved air is mixed in the air-dissolved water, the undissolved air is separated from the air-dissolved water by the deceleration of the air-dissolved water. Then, the air separated from the air-dissolved water returns to the upper part of the tank 52. As described above, in the hot water device 2 of this embodiment, the amount of undissolved air contained in the air-dissolved water that is guided to the drain outlet 64a (see FIG. 3) and the circulation opening 92a (see FIG. 3) can be reduced. Note that the solid arrows in FIG. 8 indicate the flow of water.

[0055] (Configuration of Each Water Passage in the Air Pressure Dissolution Unit 50) As shown in FIG. 1, one end of the heat source return path 60 is connected to the communication path 66, and the other end of the heat source return path 60 is connected to the circulation return path 32 of the heat source unit 10. The communication path 66 connects the first three-way valve 80 and the second three-way valve 82. The first three-way valve 80 is connected to the communication path 66, the first bathtub water passage 62, and the tank forward path 64. The first three-way valve 80 can switch between a first communication state (see FIG. 14) in which the tank forward path 64 and the first bathtub water passage 62 are in communication, a second communication state (see FIG. 1) in which the tank forward path 64 and the communication path 66 are in communication, and a third communication state (see FIGS. 11 and 12) in which the first bathtub water passage 62, the tank forward path 64, and the communication path 66 are in communication. The upstream end of the tank forward path 64 is connected to the tank 52 via the drain port 64a, and the downstream end of the tank forward path 64 is connected to the first three-way valve 80. A check valve 84 that allows water to flow from the tank 52 toward the first three-way valve 80 and prohibits water from flowing from the first three-way valve 80 toward the tank 52 is provided in the tank forward path 64. One end of the first bathtub water passage 62 is connected to the first three-way valve 80, and the other end of the first bathtub water passage 62 is connected to the bathtub adapter 132.

[0056] One end of the heat source forward path 68 is connected to the circulation forward path 30 of the heat source unit 10, and the other end of the heat source forward path 68 is connected to the second three-way valve 82. The second three-way valve 82 is connected to the communication path 66, the heat source forward path 68, and the second bathtub water passage 70. The second three-way valve 82 can switch between a fourth communication state (see FIG. 14) in which the second bathtub water passage 70 and the communication path 66 are in communication and a fifth communication state (see FIGS. 1, 11, and 12) in which the heat source forward path 68 and the second bathtub water passage 70 are in communication. One end of the second bathtub water passage 70 is connected to the second three-way valve 82, and the other end of the second bathtub water passage 70 is connected to the bathtub adapter 132.

[0057] The upstream end of the tank return path 74 is connected to the heat source forward path 68, and the downstream end of the tank return path 74 is connected to the tank 52 via the first water supply port 74a. The tank water supply valve 86 is provided in the tank return path 74 and opens and closes the tank return path 74. The tank water supply valve 86 is normally in a closed state. The first pressurizing pump 88 and the second pressurizing pump 90 are provided in the tank return path 74 between the tank water supply valve 86 and the tank 52. The first pressurizing pump 88 and the second pressurizing pump 90 pressurize the water in the tank return path 74 and send it out toward the tank 52. In the tank return path 74, the first pressurizing pump 88 is arranged upstream of the second pressurizing pump 90.

[0058] The upstream end of the tank circulation path 92 is connected to the tank 52 via the circulation opening 92a, and the downstream end of the tank circulation path 92 is connected to the tank 52 via the second water supply port 74b. The tank circulation pump 94 is provided in the tank circulation path 92. The tank circulation pump 94 sucks the water in the tank 52 into the tank circulation path 92 via the circulation opening 92a, and discharges the water in the tank circulation path 92 into the tank 52 via the second water supply port 74b.

[0059] (Configuration of the gas introduction mechanism 96) The gas introduction mechanism 96 is provided in the tank circulation path 92 upstream of the tank circulation pump 94. The gas introduction mechanism 96 includes a water inlet pipe 98, a water outlet pipe 100, a Venturi pipe 102, a gas introduction path 104, and a gas introduction valve 106. Water flows into the water inlet pipe 98 from the upstream side of the tank circulation path 92. The water outlet pipe 100 discharges water to the downstream side of the tank circulation path 92. The Venturi pipe 102 connects the water inlet pipe 98 and the water outlet pipe 100. The diameter of the Venturi pipe 102 is smaller than the diameters of the water inlet pipe 98 and the water outlet pipe 100. The water flowing through the gas introduction mechanism 96 is depressurized to a pressure lower than the atmospheric pressure when flowing from the water inlet pipe 98 to the Venturi pipe 102, and is pressurized to the original pressure when flowing from the Venturi pipe 102 to the water outlet pipe 100. The upstream end of the gas introduction path 104 (hereinafter also referred to as the gas inlet 104a) is open to the atmosphere, and the downstream end is connected to the Venturi pipe 102. The gas introduction valve 106 is provided in the gas introduction path 104 and opens and closes the gas introduction path 104. When the gas introduction valve 106 is open when water is flowing through the gas introduction mechanism 96, air is sucked into the gas introduction path 104 from the gas inlet 104a, and the air is mixed with the water flowing through the Venturi pipe 102. The air introduced through the gas introduction path 104 flows into the tank 52 together with the water flowing through the tank circulation path 92. The gas introduction valve 106 is normally in a closed state.

[0060] (Configuration of the bathtub adapter 132) Subsequently, with reference to FIGS. 9 and 10, the bathtub adapter 132 provided on the wall portion 130a of the bathtub 130 will be described. FIG. 9 shows the flow of water in the bathtub adapter 132 when water is flowing from the first bathtub water path 62 toward the bathtub 130 and water is flowing from the bathtub 130 toward the second bathtub water path 70 (for example, the state in FIG. 14). FIG. 10 shows the flow of water in the bathtub adapter 132 when water is flowing from the bathtub 130 toward the first bathtub water path 62 and water is flowing from the second bathtub water path 70 toward the bathtub 130 (for example, the state in FIG. 12).

[0061] The bathtub adapter 132 includes a first water passage 136 and a second water passage 138. The first water passage 136 communicates with the first bathtub water passage 62, and the second water passage 138 communicates with the second bathtub water passage 70. The first water passage 136 branches into a first discharge passage 136a and a first suction passage 136b. The first discharge passage 136a communicates with a first discharge port 134a provided on the front surface 132a of the bathtub adapter 132. The water discharged from the first discharge port 134a into the bathtub 130 is discharged in front of the wall portion 130a of the bathtub 130, that is, in a direction perpendicular to the wall portion 130a of the bathtub 130. In the first discharge passage 136a, a check portion 140a that prevents the flow of water from the bathtub 130 toward the first bathtub water passage 62 and a fine bubble generation nozzle 142 disposed upstream of the check portion 140a (on the side of the first bathtub water passage 62) are provided. The fine bubble generation nozzle 142 reduces the pressure of the water passing through the fine bubble generation nozzle 142. The first suction passage 136b communicates with a first suction port 134b provided on the front surface 132a of the bathtub adapter 132. In the first suction passage 136b, a check portion 140b that prevents the flow of water from the first bathtub water passage 62 toward the bathtub 130 is provided.

[0062] The second water passage 138 branches into a second discharge passage 138a and a second suction passage 138b. The second suction passage 138b communicates with a second suction port 134c provided on the front surface 132a of the bathtub adapter 132. In the second suction passage 138b, a check portion 140c that prevents the flow of water from the second bathtub water passage 70 toward the bathtub 130 is provided. The second discharge passage 138a communicates with a second discharge port 134d provided on the lower surface 132b of the bathtub adapter 132. The water discharged from the second discharge port 134d is discharged downward, that is, in a direction parallel to the wall portion 130a of the bathtub 130. In the second discharge passage 138a, a check portion 140d that prevents the flow of water from the bathtub 130 toward the second bathtub water passage 70 is provided.

[0063] (Configuration of the control device 150) The control device 150 shown in FIG. 1 controls the operations of the components of the heat source unit 10 and the air pressurization dissolution unit 50. The control device 150 is configured to be communicable with a remote controller 154 operable by a user. The control device 150 includes a memory 152 and can store various settings such as the set temperature and set water volume in the water heating operation input by the user, and the set temperature in the reheating operation. The user can instruct the start and end of the water heating operation, reheating operation, and fine bubble generation operation, which will be described later, via the remote controller 154.

[0064] (Water heating operation) The hot water filling operation starts when the user instructs the start of the hot water filling operation on the remote controller 154. Alternatively, the hot water filling operation may start when the user sets the start time of the hot water filling operation on the remote controller 154 and the control device 150 determines that the start time of the hot water filling operation has arrived. When starting the hot water filling operation, the control device 150 sets the first three-way valve 80 and the second three-way valve 82 to the third communication state and the fifth communication state, respectively (see FIGS. 11 and 12). When the hot water filling operation is started, the control device 150 opens the hot water filling valve 26 and starts heating by the first heat source unit 12. As a result, as shown in FIG. 11, the water adjusted to the set temperature flows from the hot water outlet passage 18 into the circulation return passage 32 via the hot water pouring passage 24. The water flowing into the circulation return passage 32 branches into a flow toward the upstream side (i.e., the heat source return passage 60) and a flow toward the downstream side (i.e., the second heat source unit 14). The water flowing from the circulation return passage 32 into the heat source return passage 60 flows into the bathtub 130 via the communication passage 66, the first three-way valve 80, the first bathtub water passage 62, and the bathtub adapter 132. The water flowing from the circulation return passage 32 into the second heat source unit 14 flows into the bathtub 130 via the circulation forward passage 30, the heat source forward passage 68, the second three-way valve 82, the second bathtub water passage 70, and the bathtub adapter 132. The control device 150 waits until the integrated water volume detected by the water volume sensor 28 reaches the set water volume in the hot water filling operation. Here, the integrated water volume means the integrated water volume detected by the water volume sensor 28 since the start of the hot water filling operation. When the integrated water volume reaches the set water volume, the control device 150 closes the hot water filling valve 26 and ends the heating of the water by the first heat source unit 12. Thereafter, the control device 150 notifies the user via the remote controller 154 that the hot water filling operation has been completed and ends the hot water filling operation.

[0065] (Keep-warm operation) The boost operation starts when the user instructs the start of the boost operation on the remote controller 154. Alternatively, the boost operation may start when the control device 150 determines that the temperature detected by the circulation return thermistor 32a is less than the set temperature after the first heat source unit 12 finishes heating water in the filling operation. When starting the boost operation, the control device 150 sets the first three-way valve 80 to the third communication state and the second three-way valve 82 to the fifth communication state (see FIGS. 11 and 12). From this state, the control device 150 drives the bathtub circulation pump 34 and starts heating water by the second heat source unit 14. As a result, as shown in FIG. 12, the water in the bathtub 130 is sent to the second heat source unit 14 via the bathtub adapter 132, the first bathtub water passage 62, the first three-way valve 80, the communication passage 66, the heat source return passage 60, and the circulation return passage 32. The water heated by the second heat source unit 14 is returned to the bathtub 130 via the circulation forward passage 30, the heat source forward passage 68, the second three-way valve 82, the second bathtub water passage 70, and the bathtub adapter 132. When the temperature detected by the circulation return thermistor 32a becomes equal to or higher than the set temperature, the control device 150 stops the bathtub circulation pump 34 and ends the heating of water by the second heat source unit 14. Thereafter, the control device 150 notifies the user via the remote controller 154 that the boost operation has been completed and ends the boost operation.

[0066] (Fine bubble generation operation) The fine bubble generation operation starts when the user instructs the start of the fine bubble generation operation on the remote controller 154. Also, in the hot water supply device 2 of the present embodiment, after the above-described filling operation is completed, the fine bubble generation operation is automatically started. That is, the fine bubble generation operation is executed in conjunction with the execution of the filling operation. When starting the fine bubble generation operation, the control device 150 sets the first three-way valve 80 and the second three-way valve 82 to the third communication state and the fifth communication state, respectively (see FIGS. 11 and 12). Further, the control device 150 opens the tank water supply valve 86. From this state, the control device 150 executes the process shown in FIG. 13.

[0067] In S2, the control device 150 drives the tank circulation pump 94. As a result, water circulates between the tank 52 and the tank circulation passage 92.

[0068] In S4, the control device 150 starts the first air introduction operation. Specifically, the control device 150 opens the gas introduction valve 106. During the execution of the first air introduction operation, air is introduced into the water flowing through the gas introduction mechanism 96 of the tank circulation path 92.

[0069] In S6, the control device 150 starts the pressurized water supply operation. Specifically, as shown in FIG. 14, the control device 150 sets the first three-way valve 80 to the first communication state and the second three-way valve 82 to the fourth communication state, and then drives the bathtub circulation pump 34, the first pressurization pump 88, and the second pressurization pump 90. During the execution of the pressurized water supply operation, the water in the bathtub 130 passes through the bathtub adapter 132, the second bathtub water path 70, the second three-way valve 82, the communication path 66, the heat source return path 60, the circulation return path 32, the second heat source unit 14, the circulation forward path 30, the heat source forward path 68, and the tank return path 74 and is supplied to the tank 52. At this time, the water pressurized by the first pressurization pump 88 and the second pressurization pump 90 is supplied from the tank return path 74 to the tank 52. As a result, air is pressurized and dissolved in the water inside the tank 52. Then, the water in which air is pressurized and dissolved is supplied from the tank 52 to the bathtub 130 via the tank forward path 64, the first three-way valve 80, the first bathtub water path 62, and the bathtub adapter 132. At this time, when the water in which air is pressurized and dissolved passes through the fine bubble generation nozzle 142 of the first discharge path 136a of the bathtub adapter 132, it is depressurized to below atmospheric pressure, and when it is ejected into the bathtub 130, it is pressurized to atmospheric pressure, and fine bubbles are generated in the water of the bathtub 130.

[0070] In S8, the control device 150 determines whether the water level in the tank 52 is lower than the first water level based on the detection signal from the low water level electrode 54b. In this embodiment, in the gas introduction mechanism 96, the amount of air introduced when the gas introduction valve 106 is open is larger than the amount of air in the fine bubbles generated in the water in the bathtub 130. Therefore, when the gas introduction valve 106 is open, the amount of air in the tank 52 increases, and the water level in the tank 52 decreases. When the water level in the tank 52 is equal to or higher than the first water level (in the case of NO), the process proceeds to S12. When the water level in the tank 52 is lower than the first water level (in the case of YES), the process proceeds to S10.

[0071] In S10, if the first air introduction operation is being executed, the control device 150 stops the first air introduction operation. Specifically, the control device 150 closes the gas introduction valve 106. As a result, the introduction of air into the water flowing through the gas introduction mechanism 96 in the tank circulation path 92 is stopped. When the gas introduction valve 106 is closed, no air is supplied to the tank 52, so the amount of air in the tank 52 decreases, and the water level in the tank 52 rises. In this embodiment, even while the gas introduction valve 106 is closed, the driving of the tank circulation pump 94 continues as it is. As a result, the flow of water in the tank 52 is promoted, and the pressure dissolution of air into the water in the tank 52 is promoted.

[0072] In S12, the control device 150 determines whether the water level in the tank 52 is equal to or higher than the second water level based on the detection signal from the high water level electrode 54a. When the water level in the tank 52 is lower than the second water level (in the case of NO), the process proceeds to S16. When the water level in the tank 52 is equal to or higher than the second water level (in the case of YES), the process proceeds to S14.

[0073] In S14, if the first air introduction operation has been stopped, the control device 150 starts the first air introduction operation. As a result, the introduction of air into the water flowing through the gas introduction mechanism 96 in the tank circulation path 92 is resumed.

[0074] In S16, the control device 150 determines whether the operation time of the fine bubble generation operation has reached the set time. Here, the operation time of the fine bubble generation operation is the elapsed time since the start of the fine bubble generation operation. In the hot water supply device 2 of the present embodiment, when the fine bubble generation operation is executed independently without being linked to the execution of the water filling operation, the set time is set to, for example, 10 minutes. Different from this, when the fine bubble generation operation is executed in conjunction with the execution of the water filling operation, the set time is set to, for example, 30 minutes. If the operation time has not reached the set time (in the case of NO), the process returns to S8. When the operation time reaches the set time (when it becomes YES), the process proceeds to S18.

[0075] In S18, the control device 150 stops the pressurized water supply operation. Specifically, the control device 150 stops the bathtub circulation pump 34, the first pressurizing pump 88, and the second pressurizing pump 90.

[0076] In S20, if the first air introduction operation is being executed, the control device 150 stops the first air introduction operation.

[0077] In S22, the control device 150 stops the tank circulation pump 94. As a result, the circulation of water between the tank 52 and the tank circulation path 92 stops. After S22, the process of FIG. 13 ends.

[0078] Thus, in the hot water supply device 2 of the present embodiment, the control device 150 is configured to control the operation of the gas introduction mechanism 96 using the high water level electrode 54a and the low water level electrode 54b so that the water level in the tank 52 transitions between the first water level and the second water level during the fine bubble generation operation. Further, the control device 150 is configured to execute the first gas introduction operation without interrupting the pressurized water supply operation when the first gas introduction operation is executed during the execution of the pressurized water supply operation in the fine bubble generation operation.

[0079] (Embodiment 2) As shown in FIG. 15, the hot water device 2A of this embodiment has substantially the same configuration as the hot water device 2 of Embodiment 1. In the hot water device 2A, instead of including the tank 52, the air pressurization and dissolution unit 50 includes a tank 72. Further, in the hot water device 2A, when executing the fine bubble generation operation, instead of the control device 150 executing the process shown in FIG. 13, the process shown in FIG. 19 is executed. Hereinafter, the differences between the tank 72 and the tank 52 and the differences between the process shown in FIG. 19 and the process shown in FIG. 13 will be described.

[0080] (Differences between the tank 72 and the tank 52) As shown in FIG. 16, the tank 72 includes a tank upper portion 720 instead of the tank upper portion 520. And the tank upper portion 720 includes an electrode installation portion 740 instead of the electrode installation portion 540. An electrode unit 754 is installed in the electrode installation portion 740 instead of the electrode unit 54.

[0081] The electrode unit 754 includes a single water level electrode 754a and a ground electrode 754b. The single water level electrode 754a and the ground electrode 754b extend in the vertical direction inside the tank 72 and outside the mixing case 4. When the single water level electrode 754a comes into contact with the water surface of the water stored in the tank 72, a current flows between the single water level electrode 754a and the ground electrode 754b, and an ON signal is output to the control device 150. That is, the single water level electrode 754a is configured to be able to detect whether the water level in the tank 72 is equal to or higher than a predetermined water level. Hereinafter, the water level in the tank 72 detected by the single water level electrode 754a may be referred to as the "third water level". The lower end of the single water level electrode 754a is at a position higher than the lower end of the mixing case 4. For this reason, the third water level is at a position higher than the lower end of the mixing case 4.

[0082] As shown in FIG. 17, a single water level electrode 754a is covered by an electrode cover 446. On the other hand, the ground electrode 754b is not covered by the electrode cover 446. The lower end of the electrode cover 446 is at a position lower than the lower end of the single water level electrode 754a and the lower end of the ground electrode 754b. Also, the lower end of the electrode cover 446 is at a position lower than the lower end of the mixing case 4.

[0083] As shown in FIG. 18, when the electrode cover 446 is viewed from below, the electrode cover 446 covers the entire circumference of the single water level electrode 754a.

[0084] (Differences between the process shown in FIG. 13 and the process shown in FIG. 19) In the process shown in FIG. 19, after S6, the process proceeds to S32. In S32, the control device 150 determines whether the water level in the tank 72 is below the third water level based on the presence or absence of an ON signal output from the single water level electrode 754a. If the water level in the tank 72 is at or above the third water level (NO), the process repeats S32. If the water level in the tank 72 is below the third water level (YES), the process proceeds to S10. And after S10, the process proceeds to S34.

[0085] In S34, the control device 150 starts measuring the water level rise time using a built-in timer (not shown). After S34, the process proceeds to S36.

[0086] In S36, the control device 150 determines whether the water level rise time started in S34 exceeds a first predetermined time (for example, 90 seconds). If the water level rise time is less than or equal to the first predetermined time (NO), the process repeats S36. If the water level rise time exceeds the first predetermined time (YES), the process proceeds to S38.

[0087] In S38, the control device 150 ends the measurement of the water level rise time by a built-in timer (not shown). After S38, the process proceeds to S14.

[0088] As described above, in the hot water supply device 2A, in the fine bubble generation operation, the control device 150 is configured to control the operation of the gas introduction mechanism 96 so that the water level in the tank 72 is maintained at the third water level or higher using a single water level electrode 754a. Further, in the fine bubble generation operation, when the first gas introduction operation is executed during the pressurized water supply operation, the control device 150 is configured to execute the first gas introduction operation without interrupting the pressurized water supply operation.

[0089] (Example 3) As shown in FIG. 20, the hot water supply device 2B of this embodiment has substantially the same configuration as the hot water supply device 2 of Example 1. In the hot water supply device 2B, instead of including the tank 52, the air pressurization and dissolution unit 50 includes a tank 352. The tank 352 does not have the circulation opening 92a in the tank 52. Instead of including the first water supply port 74a and the second water supply port 74b in the tank 52, the tank 352 includes a third water supply port 374. The downstream end of the tank return path 74 is connected to the third water supply port 374. Further, in the hot water supply device 2B, instead of including the tank circulation path 92, the tank circulation pump 94, and the gas introduction mechanism 96, the air pressurization and dissolution unit 50 includes a gas introduction path 300 and an air pump 302. The upstream end of the gas introduction path 300 (hereinafter also referred to as the gas inlet 300a) is open to the atmosphere, and the downstream end is connected to the tank 52. The air pump 302 is provided in the gas introduction path 300. When the air pump 302 is driven, air is introduced into the tank 52 through the gas introduction path 300.

[0090] Further, in the hot water supply device 2B, when executing the fine bubble generation operation, instead of the control device 150 executing the process shown in FIG. 13, the process shown in FIG. 21 is executed.

[0091] As shown in FIG. 21, in S52, the control device 150 starts the second air introduction operation. Specifically, the control device 150 drives the air pump 302 after setting the first three-way valve 80 and the second three-way valve 82 to the second communication state and the fifth communication state (see FIG. 20), respectively. During the execution of the second air introduction operation, air is introduced into the tank 352 through the gas introduction path 300.

[0092] In S54, based on the detection signal from the low water level electrode 54b, the control device 150 determines whether the water level in the tank 352 is below the first water level. When the second air introduction operation is executed with the pressurized water supply operation (described later) stopped, since the amount of air in the tank 352 increases, the water level in the tank 352 will drop. When the water level in the tank 352 is equal to or higher than the first water level (NO case), the process proceeds to S60. When the water level in the tank 352 is below the first water level (YES case), the process proceeds to S56.

[0093] In S56, when the second air introduction operation is in progress, the control device 150 stops the second air introduction operation. Specifically, the control device 150 stops the air pump 302. As a result, the introduction of air into the tank 352 is stopped.

[0094] In S58, when the pressurized water supply operation is stopped, the control device 150 starts the pressurized water supply operation. Specifically, as shown in FIG. 22, the control device 150 sets the first three-way valve 80 and the second three-way valve 82 to the first communication state and the fourth communication state, respectively, and then drives the bathtub circulation pump 34, the first pressurizing pump 88, and the second pressurizing pump 90. As a result, the pressurized dissolution of air into the water in the tank 352 is promoted, and the supply of air-dissolved water from the tank 352 to the bathtub 130 is started. When the second air introduction operation is stopped, since no air is supplied to the tank 352, the amount of air in the tank 352 decreases, and the water level in the tank 352 rises.

[0095] In S60, based on the detection signal from the high water level electrode 54a, the control device 150 determines whether the water level in the tank 352 is equal to or higher than the second water level. When the water level in the tank 352 is below the second water level (NO case), the process proceeds to S66. When the water level in the tank 352 is equal to or higher than the second water level (YES case), the process proceeds to S62.

[0096] In S62, when the second air introduction operation has stopped, the control device 150 starts the second air introduction operation. As a result, the introduction of air into the inside of the tank 352 resumes.

[0097] In S64, when the pressurized water supply operation is being executed, the control device 150 stops the pressurized water supply operation. As a result, the supply of air-dissolved water from the tank 352 to the bathtub 130 stops. Also, since the second air introduction operation is executed while the pressurized water supply operation is stopped, the water level in the tank 352 decreases.

[0098] In S66, the control device 150 determines whether the operation time of the fine bubble generation operation has reached the set time. If the operation time has not reached the set time (in the case of NO), the process returns to S54. When the operation time reaches the set time (when it becomes YES), the process proceeds to S68.

[0099] In S68, when the pressurized water supply operation is being executed, the control device 150 stops the pressurized water supply operation.

[0100] In S70, when the second air introduction operation is being executed, the control device 150 stops the second air introduction operation. After S70, the process of FIG. 21 ends.

[0101] In this way, in the hot water device 2B, the control device 150 is configured to control the operation of the air pump 302 using the high water level electrode 54a and the low water level electrode 54b so that the water level in the tank 352 changes between the first water level and the second water level during the fine bubble generation operation. Also, the control device 150 is configured to interrupt the pressurized water supply operation at the start of the second air introduction operation and resume the interrupted pressurized water supply operation at the stop of the second air introduction operation when the second air introduction operation is executed during the execution of the pressurized water supply operation in the fine bubble generation operation.

[0102] In the water heater 2B, the tank 352 may be provided with the electrode unit 754 of the second embodiment instead of the electrode unit 54. In this case, the control device 150 may be configured to control the operation of the air pump 302 using a single water level electrode 754a so that the water level in the tank 352 is maintained at the third water level or higher during the microbubble generation operation. Also in this case, when the control device 150 executes the second air introduction operation during the pressurized water supply operation in the microbubble generation operation, the control device 150 may be configured to interrupt the pressurized water supply operation at the start of the second air introduction operation and resume the interrupted pressurized water supply operation at the stop of the second air introduction operation.

[0103] (Modification example) In the above-described water heater 2 (or water heater 2A, water heater 2B), air is introduced into the tank 52 (or tank 72, tank 352). However, instead of air, a gas such as carbon dioxide gas, hydrogen, or oxygen may be introduced into the tank 52 (or tank 72, tank 352). In this case, a gas-filled tank (not shown) filled with the gas may be connected to the gas inlet 104a of the gas introduction passage 104 (or the gas inlet 300a of the gas introduction passage 300).

[0104] In the above-described water heater 2 (or water heater 2A, water heater 2B), the heat source unit 10 is connected to the calan 250, and the air pressurization and dissolution unit 50 is connected to the bathtub 130. In another embodiment, the heat source unit 10 may be connected to another heat utilization location, or the air pressurization and dissolution unit 50 may be connected to another liquid tank.

[0105] In the above-described water heater 2 (or water heater 2A), the drain port 64a and the circulation opening 92a are provided on the lower surface of the lower part 522 of the tank and open downward. In another embodiment, each of the drain port 64a and the circulation opening 92a may not be provided on the lower surface of the lower part 522 of the tank and may not open downward. For example, at least one of the drain port 64a and the circulation opening 92a may be provided on the side surface of the lower part 522 of the tank and may open in the horizontal direction.

[0106] In the above-described hot water device 2 (or hot water device 2A, hot water device 2B), the plate-like member 406 is integrally formed with the first side wall portion 402 seamlessly. In another embodiment, the plate-like member 406 may be provided separately from the first side wall portion 402.

[0107] In the above-described hot water device 2 (or hot water device 2A, hot water device 2B), the plate-like member 406 is provided along the horizontal direction. In another embodiment, the plate-like member 406 may not be provided along the horizontal direction. For example, the plate-like member 406 may be provided along a plane inclined with respect to the horizontal direction.

[0108] In the above-described hot water device 2 (or hot water device 2A, hot water device 2B), the plate-like member 406 is a flat plate having a substantially fan-shaped shape centered on the axis A. In another embodiment, the plate-like member 406 may not have a substantially fan-shaped shape centered on the axis A, or may not be a flat plate. For example, the plate-like member 406 may be a flat plate having a substantially circular shape centered on the axis A, or may be a plate having a substantially fan-shaped shape centered on the axis A and curved upward toward the circumferential end portion of the axis A.

[0109] In the above-described hot water device 2 (or hot water device 2A, hot water device 2B), the plate-like member 406 is in contact with the case installation portion 550 of the lower part 522 of the tank from above. That is, the plate-like member 406 protrudes radially outward of the axis A beyond the inner surface of the lower part 522 of the tank. In another embodiment, the plate-like member 406 may not protrude radially outward of the axis A beyond the inner surface of the lower part 522 of the tank.

[0110] In the above-described hot water device 2 (or hot water device 2A, hot water device 2B), the electrode cover 446 is integrally formed seamlessly with the upper plate portion 440, the enlarged diameter portion 442, and the side plate portion 444. In another embodiment, the electrode cover 446 may be provided separately from the upper plate portion 440, the enlarged diameter portion 442, and the side plate portion 444. In yet another embodiment, a part of the electrode cover 446 may be constituted by the inner surface of the tank 52 (or tank 72, tank 352), and the remaining part of the electrode cover 446 may be integrally formed seamlessly with the upper plate portion 440, the enlarged diameter portion 442, and the side plate portion 444. Also in this case, when the electrode cover 446 is viewed from below, the electrode cover 446 may cover the entire circumference of the high water level electrode 54a (or single water level electrode 754a).

[0111] In the above-described hot water device 2 (or hot water device 2B), the electrode cover 446 covers only the high water level electrode 54a. In another embodiment, the electrode cover 446 may cover at least one of the water level electrodes including the high water level electrode 54a, the low water level electrode 54b, and the ground electrode 54c. For example, the electrode cover 446 may cover both the high water level electrode 54a and the low water level electrode 54b.

[0112] In the above-described hot water device 2A, the electrode cover 446 covers only the single water level electrode 754a. In another embodiment, the electrode cover 446 may cover both the single water level electrode 754a and the ground electrode 754b.

[0113] In the above-described hot water device 2 (or hot water device 2A, hot water device 2B), a water level electrode for detecting the water level in the tank 52 (or tank 72, tank 352) may be provided in addition to the high water level electrode 54a and the low water level electrode 54b (or single water level electrode 754a).

[0114] The lengths of the high water level electrode 54a and the low water level electrode 54b (or single water level electrode 754a) in the above-described hot water device 2 (or hot water device 2A, hot water device 2B) may be appropriately changed. That is, the first water level and the second water level (or third water level) in the above-described hot water device 2 may be appropriately changed.

[0115] In the above-described hot water device 2 (or hot water device 2A), in the tank circulation path 92, the gas introduction mechanism 96 is arranged upstream of the tank circulation pump 94. In another embodiment, in the tank circulation path 92, the gas introduction mechanism 96 may be arranged downstream of the tank circulation pump 94.

[0116] In the above-described hot water device 2 (or hot water device 2A), the downstream end of the tank circulation path 92 is connected to the tank return path 74 downstream of the second pressurizing pump 90. In another embodiment, the downstream end of the tank circulation path 92 may not be connected to the tank return path 74 and may be provided separately from the tank return path 74 with respect to the tank 52 (or tank 72).

[0117] In the above-described hot water device 2 (or hot water device 2A, hot water device 2B), in the filling operation, based on the integrated water volume detected by the water volume sensor 28, the set water volume of water is stored in the bathtub 130. In another embodiment, the hot water device 2 (or hot water device 2A, hot water device 2B) may be provided with a water level sensor capable of detecting the water level of the bathtub 130, for example, and in the filling operation, based on the water level of the bathtub 130 detected by the water level sensor, the water of the set water level may be stored in the bathtub 130.

[0118] In the above-described hot water device 2 (or hot water device 2A, hot water device 2B), whether or not to execute the fine bubble generation operation in conjunction with the execution of the filling operation may be switchable by the user via the remote controller 154.

[0119] In the above-described hot water device 2 (or hot water device 2A or hot water device 2B), when the operation time of the fine bubble generation operation reaches the set time (YES in S16 of FIG. 13, YES in S16 of FIG. 19, or YES in S66 of FIG. 21), the control device 150 ends the fine bubble generation operation. In another embodiment, the control device 150 may end the fine bubble generation operation even when the operation time of the fine bubble generation operation has not reached the set time. For example, the control device 150 may end the fine bubble generation operation when the user instructs to end the fine bubble generation operation via the remote control 154.

[0120] The first predetermined time in the above-described hot water device 2A and the set time for stopping the fine bubble operation in the above-described hot water device 2 (or hot water device 2A or hot water device 2B) may be changed as appropriate.

[0121] (Corresponding relationship) As described above, in one or more embodiments, the hot water device 2 (or the hot water device 2A, the hot water device 2B) (an example of a fine bubble generator) includes a tank 52 (or the tank 72, the tank 352) having a first water supply port 74a (or the third water supply port 374) (an example of a supply port) and a drain port 64a (an example of a discharge port), a mixing case 4 housed in the tank 52 (or the tank 72, the tank 352) and configured to pressurize and dissolve air (an example of a gas) in the tank 52 (or the tank 72, the tank 352) into water (an example of a liquid) flowing into the interior, a tank return path 74 (an example of a supply path) that supplies water to the first water supply port 74a (or the third water supply port 374), an introduction pipe 46 (an example of an introduction path) that introduces the water supplied to the first water supply port 74a and the second water supply port 74b (or the third water supply port 374) into the interior of the mixing case 4, a tank forward path 64 (an example of a discharge path) that discharges the water stored in the tank 52 (or the tank 72, the tank 352) from the drain port 64a to a bathtub 130 (an example of a liquid tank), a fine bubble generating nozzle 142 provided in the tank forward path 64 and configured to generate fine bubbles by decompressing the water in which air is pressurized and dissolved, a high water level electrode 54a and a low water level electrode 54b (or a single water level electrode 754a) (an example of one or more liquid level electrodes) that extend vertically inside the tank 52 (or the tank 72, the tank 352) and outside the mixing case 4 and are capable of detecting whether the water level in the tank 52 (or the tank 72, the tank 352) is equal to or higher than a predetermined water level, and an electrode cover 446 provided so as to cover the high water level electrode 54a (or the single water level electrode 754a) (an example of at least one of one or more liquid level electrodes). The mixing case 4 is provided with a plurality of outflow portions 404 from which water flows out. The water supplied from the tank return path 74 to the first water supply port 74a (or the third water supply port 374) is introduced into the interior of the mixing case 4 via the introduction pipe 46 and flows out from the plurality of outflow portions 404 to the outside of the mixing case 4, so as to be stored in the tank 52 (or the tank 72, the tank 352). When the electrode cover 446 is viewed from below (an example of when viewed along the extending direction of at least one of one or more liquid level electrodes), the electrode cover 446 covers the entire circumference of the high water level electrode 54a (or the single water level electrode 754a).

[0122] According to the above configuration, the electrode cover 446 can suppress the adhesion of water droplets (examples of liquid droplets) scattered from the water surface (example of a liquid level surface) to the high water level electrode 54a (or the single water level electrode 754a) over the entire circumference of the high water level electrode 54a (or the single water level electrode 754a). Therefore, the adhesion of water droplets to the high water level electrode 54a (or the single water level electrode 754a) can be appropriately suppressed.

[0123] In one or more embodiments, the hot water device 2 (or the hot water device 2A, the hot water device 2B) further includes a first pressurizing pump 88 and a second pressurizing pump 90 (examples of pressurizing pumps) provided in the tank return path 74, a gas introduction mechanism 96 (or an air pump 302) (an example of a gas introduction mechanism) capable of introducing air into the tank 52 (or the tank 72, the tank 352), and a control device 150. The control device 150 drives the first pressurizing pump 88 and the second pressurizing pump 90 to pressurize and supply water from the tank return path 74 to the first water supply port 74a (or the third water supply port 374), and supplies water in which air is pressurized and dissolved from the drain port 64a to the bathtub 130 via the tank forward path 64, which is a pressurized water supply operation (an example of a pressurized liquid supply operation), and operates the gas introduction mechanism 96 (or the air pump 302) to introduce air into the tank 52 (or the tank 72, the tank 352), which is a first gas introduction operation (or a second gas introduction operation), and is configured to be able to execute a fine bubble generation operation including these operations. When the lowest first water level (or the boundary water level) among the predetermined water levels detected by the high water level electrode 54a and the low water level electrode 54b (or the single water level electrode 754a) is set as the lower limit water level, in the fine bubble generation operation, when it is detected that the water level in the tank 52 (or the tank 72, the tank 352) is lower than the lower limit water level during the execution of the first gas introduction operation (or the second gas introduction operation), the control device 150 stops the first gas introduction operation (or the second gas introduction operation) and is configured to raise the water level in the tank 52 (or the tank 72, the tank 352) by executing only the pressurized water supply operation. The lower end of the electrode cover 446 is located at a position lower than the lower end of the low water level electrode 54b (or the lower end of the single water level electrode 754a). That is, the lower end of the electrode cover 446 is located at a position lower than the lower limit water level.

[0124] When the lower end of the electrode cover 446 is at a position lower than the water level in the tank 52 (or tank 72, tank 352), the electrode cover 446 suppresses the air contained in the water in the tank 52 (or tank 72, tank 352) from rising in the water and entering the inside of the electrode cover 446. In this case, inside the electrode cover 446, the generation of foam on the water surface is suppressed, and the scattering of water droplets above the water surface is suppressed. According to the above configuration, during the execution of the fine bubble generation operation, the lower end of the electrode cover 446 is always at a position lower than the water level in the tank 52 (or tank 72, tank 352). Therefore, during the execution of the fine bubble generation operation, inside the electrode cover 446, the generation of foam on the water surface is always suppressed, and the scattering of water droplets above the water surface is always suppressed. Thus, according to the above configuration, the adhesion of water droplets to the high water level electrode 54a (or the single water level electrode 754a) can be more appropriately suppressed.

[0125] In one or more embodiments, one or more water level electrodes include a low water level electrode 54b (an example of a first liquid level electrode) capable of detecting whether the water level in the tank 52 (or tank 352) is equal to or higher than a first water level (an example of a first liquid level) and a high water level electrode 54a (an example of a second liquid level electrode) capable of detecting whether the water level in the tank 52 (or tank 352) is equal to or higher than a second water level (an example of a second liquid level) that is higher than the lower water level. The lower water level is the first water level. In the fine bubble generation operation, when it is detected that the water level in the tank 52 (or tank 352) is equal to or higher than the second water level during the stop of the first gas introduction operation (or the second gas introduction operation), the control device 150 is configured to start the first gas introduction operation (or the second gas introduction operation) to lower the water level in the tank 52 (or tank 352).

[0126] According to the above configuration, the control device 150 uses the low water level electrode 54b and the high water level electrode 54a to control the operation of the gas introduction mechanism 96 (or the air pump 302) so that the water level in the tank 52 (or the tank 352) changes between the first water level and the second water level. And the lower end of the electrode cover 446 covering the high water level electrode 54a is at a position lower than the lower end of the low water level electrode 54b (an example of being lower than the first liquid level). According to the above configuration, in the water heater 2 (or the water heater 2B) that controls the water level in the tank 52 (or the tank 352) using the low water level electrode 54b and the high water level electrode 54a (an example of two liquid level electrodes), the scattering of water droplets inside the electrode cover 446 is always suppressed. For this reason, in the water heater 2 (or the water heater 2B) that controls the water level in the tank 52 (or the tank 352) using the low water level electrode 54b and the high water level electrode 54a, the adhesion of droplets to the high water level electrode 54a can be appropriately suppressed.

[0127] In one or more embodiments, the electrode cover 446 is provided to cover the high water level electrode 54a among the low water level electrode 54b and the high water level electrode 54a.

[0128] When the control device 150 controls the operation of the gas introduction mechanism 96 (or the air pump 302) so that the water level in the tank 52 (or the tank 352) changes between the first water level and the second water level, since the low water level electrode 54b is frequently immersed in water, slime is relatively unlikely to occur on the low water level electrode 54b. On the other hand, since the high water level electrode 54a is hardly immersed in water, slime is relatively likely to occur on the high water level electrode 54a. According to the above configuration, the electrode cover 446 is provided to cover the high water level electrode 54a. For this reason, the adhesion of water droplets to the high water level electrode 54a where slime is relatively likely to occur can be appropriately suppressed.

[0129] In one or more embodiments, one or more water level electrodes include only a single water level electrode 754a (an example of a third liquid level electrode) capable of detecting whether the water level in the tank 72 (or the tank 352) is equal to or higher than a third water level (an example of a third liquid level). The electrode cover 446 is provided to cover the single water level electrode 754a. The lower limit water level is the third water level. When the control device 150 detects that the water level in the tank 72 (or the tank 352) is lower than the lower limit water level during the fine bubble generation operation and stops the first gas introduction operation (or the second gas introduction operation), the control device 150 maintains the stopped state of the first gas introduction operation (or the second gas introduction operation) until a first predetermined time elapses after stopping the first gas introduction operation (or the second gas introduction operation), and is configured to start the first gas introduction operation (or the second gas introduction operation) after the elapse of the first predetermined time.

[0130] According to the above configuration, the control device 150 controls the operation of the gas introduction mechanism 96 (or the air pump 302) using the single water level electrode 754a so that the water level in the tank 72 (or the tank 352) is maintained at or above the third water level. The lower end of the electrode cover 446 covering the single water level electrode 754a is at a position lower than the lower end of the single water level electrode 754a (an example of a position lower than the third liquid level). According to the above configuration, in the hot water device 2B that controls the water level in the tank 72 (or the tank 352) using the single water level electrode 754a (an example of one liquid level electrode), the scattering of water droplets inside the electrode cover 446 is always suppressed. Therefore, in the hot water device 2A (or the hot water device 2B) that controls the water level in the tank 72 (or the tank 352) using the single water level electrode 754a, the adhesion of water droplets to the single water level electrode 754a can be appropriately suppressed.

[0131] In one or more embodiments, the third water level is at a position higher than the lower end of the mixing case 4. The lower end of the electrode cover 446 is at a position lower than the lower end of the mixing case 4.

[0132] The water supplied to the tank 72 (or the tank 352) is stored along the shape of the outer surface of the mixing case 4 and the shape of the inner surface of the tank 72 (or the tank 352). For this reason, the horizontal cross-sectional area of the water stored in the tank 72 (or the tank 352) is relatively large at a position lower than the lower end of the mixing case 4 and relatively small at a position higher than the lower end of the mixing case 4. Therefore, the amount of air rising in the water per unit area is relatively small at a position lower than the lower end of the mixing case 4 and relatively large at a position higher than the lower end of the mixing case 4. According to the above configuration, the electrode cover 446 extends to a position where the amount of air rising in the water per unit area is relatively small. For this reason, the electrode cover 446 can further suppress the air contained in the water in the tank 72 (or the tank 352) from rising in the water and entering the inside of the electrode cover 446.

[0133] In one or more embodiments, when the control device 150 executes the second gas introduction operation during the pressurized water supply operation in the fine bubble generation operation, at the start of the second gas introduction operation, the pressurized water supply operation is interrupted, and at the stop of the second gas introduction operation, the interrupted pressurized water supply operation is restarted.

[0134] When the pressurized water supply operation is not interrupted when the gas introduction operation is executed, it is necessary to adjust the amount of air supplied to the tank 352 in the gas introduction operation so that it exceeds the amount of air consumed from the tank 352 in the pressurized water supply operation, and the process may become complicated. According to the above configuration, since the pressurized water supply operation is interrupted when the second gas introduction operation is executed, there is no need to adjust the amount of air supplied to the tank 352 in the second gas introduction operation and the amount of air consumed from the tank 352 in the pressurized water supply operation, and the process can be simplified.

[0135] In one or more embodiments, when the control device 150 executes the first gas introduction operation during the pressurized water supply operation in the fine bubble generation operation, the control device 150 is configured to execute the first gas introduction operation without interrupting the pressurized water supply operation.

[0136] When interrupting the pressurized water supply operation to execute the gas introduction operation, the fine bubbles generated in the water of the bathtub 130 during the pressurized water supply operation may disappear during the execution of the gas introduction operation, and there is a possibility that the fine bubbles cannot be continuously and stably generated in the water of the bathtub 130. According to the above configuration, it is not necessary to interrupt the pressurized water supply operation to execute the first gas introduction operation, and the pressurized water supply operation can be continuously executed. According to the above configuration, the fine bubbles can be continuously and stably generated in the water of the bathtub 130.

[0137] In one or more embodiments, the electrode cover 446 is integrally formed seamlessly with the case lid 44 (an example of a part of the mixing case).

[0138] In the manufacturing process of the hot water device 2 (or the hot water device 2A, the hot water device 2B), there may be a case where it is desired to reduce the number of parts. According to the above configuration, the number of parts can be reduced compared to the case where the electrode cover 446 and the mixing case 4 are provided separately.

[0139] In one or more embodiments, the liquid is water. The liquid tank is the bathtub 130 used by the user for bathing.

[0140] According to the above configuration, in the hot water device 2 (or the hot water device 2A, the hot water device 2B) that generates fine bubbles in the water of the bathtub 130 used by the user for bathing, the adhesion of water droplets to the high water level electrode 54a (or the single water level electrode 754a) can be appropriately suppressed.

[0141] Although the embodiments have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Also, the technology illustrated in this specification or the drawings can achieve multiple purposes simultaneously, and achieving one of these purposes itself has technical utility.

Explanation of Symbols

[0142] 2, 2A, 2B: Hot water device 4: Mixing case 10: Heat source unit 12: First heat source machine 14: Second heat source machine 16: Water supply path 18: Hot water outlet path 18a: Hot water outlet temperature thermistor 20: Bypass path 22: Bypass servo 24: Pouring path 26: Valve 28: Water volume sensor 30: Circulation forward path 30a: Circulation forward path thermistor 32: Circulation return path 32a: Circulation return path thermistor 34: Bathtub circulation pump 36: Water flow switch 40: Case body 42: Stirring part 44: Case cover 46: Introduction pipe 50: Air pressurization dissolution unit 52, 72, 352: Tank 54, 754: Electrode unit 54a: High water level electrode 54b: Low water level electrode 54c, 754b: Earth electrode 60: Heat source return path 62: First bathtub water path 64: Tank forward path 64a: Drainage port 66: Communication path 68: Heat source forward path 70: Second bathtub water path 74: Tank return path 74a: First water supply port 74b: Second water supply port 80: First three-way valve 82: Second three-way valve 84: Check valve 86: Tank water supply valve 88: First pressurizing pump 90: Second pressurizing pump 92: Tank circulation path 92a: Circulation opening 94: Tank circulation pump 96: Gas introduction mechanism 98: Inlet pipe 100: Outlet pipe 102: Venturi tube 104: Gas introduction path 104a: Gas inlet 106: Gas introduction valve 130: Bathtub 130a: Wall part 132: Bathtub adapter 132a: Front surface 132b: Bottom surface 134a: First discharge port 134b: First suction port 134c: Second suction port 134d: Second discharge port 136: First water path 136a: First discharge path 136b: First suction path 138: Second water path 138a: Second discharge path 138b: Second suction path 140a, 140b, 140c, 140d: Check part 142: Microbubble generation nozzle 150: Control device 152: Memory 154: Remote control 200: Water supply source 250: Faucet 300: Gas introduction path 300a: Gas inlet 302: Air pump 374: Third water supply port 400: First bottom plate part 402: First side wall part 404: Plural outflow parts 404a: First outflow part 404b: Second outflow part 404c: Third outflow part 404d: Fourth outflow part 406: Plate-shaped member 408: Plurality of placement members 408a: First placement member 408b: Second placement member 408c: Third placement member 420: Second bottom plate part 422: Second side wall part 424: Insertion tube 425: Jet outlet 426: Fitting member 428: Flange part 440: Upper plate part 442: Diameter-expanded part 444: Side plate part 446: Electrode cover 520, 720: Tank upper part 522: Tank lower part 540, 740: Electrode installation part 550: Case installation part 754a: Single water level electrode

Claims

1. A tank having a supply port and a discharge port, A mixing case that is accommodated in the tank and pressurizes and dissolves the gas in the tank into the liquid flowing into the interior thereof, A supply path that supplies the liquid to the supply port, An introduction path that introduces the liquid supplied to the supply port into the interior of the mixing case, A discharge path that discharges the liquid stored in the tank from the discharge port to a liquid tank, A fine bubble generation nozzle that is provided in the discharge path and generates fine bubbles by depressurizing the liquid in which the gas is pressurized and dissolved, One or a plurality of liquid level electrodes that extend in the vertical direction inside the tank and outside the mixing case and can detect whether the liquid level in the tank is equal to or higher than a predetermined liquid level, An electrode cover provided so as to cover at least one of the one or a plurality of liquid level electrodes, The mixing case is provided with an outflow portion through which the liquid flows out, The liquid supplied from the supply path to the supply port is introduced into the interior of the mixing case via the introduction path and flows out from the outflow portion to the outside of the mixing case, thereby being configured to be stored in the tank, When the electrode cover is viewed along the extending direction of at least one of the one or a plurality of liquid level electrodes, the electrode cover covers the entire circumference of at least one of the one or a plurality of liquid level electrodes. A fine bubble generator.

2. A pressure pump provided in the supply path, A gas introduction mechanism capable of introducing gas into the tank, A control device, The control device, A pressurized liquid supply operation in which the pressure pump is driven to pressurize and supply the liquid from the supply path to the supply port and supply the liquid in which the gas is pressurized and dissolved from the discharge port to the liquid tank via the discharge path, A fine bubble generation operation including a gas introduction operation in which the gas is introduced into the tank by operating the gas introduction mechanism is configured to be executable, When the lowest liquid level among the predetermined liquid levels detected by the one or a plurality of liquid level electrodes is set as the lower limit liquid level, In the microbubble generation operation, when it is detected that the liquid level in the tank is lower than the lower limit liquid level during the execution of the gas introduction operation, the control device stops the gas introduction operation and increases the liquid level in the tank by only executing the pressurized liquid supply operation. The microbubble generator according to claim 1, wherein the lower end of the electrode cover is located at a position lower than the lower limit liquid level.

3. The one or more liquid level electrodes include a first liquid level electrode capable of detecting whether the liquid level in the tank is equal to or higher than a first liquid level, and a second liquid level electrode capable of detecting whether the liquid level in the tank is equal to or higher than a second liquid level higher than the first liquid level. The lower limit liquid level is the first liquid level. In the microbubble generation operation, when it is detected that the liquid level in the tank is equal to or higher than the second liquid level during the stop of the gas introduction operation, the control device starts the gas introduction operation to lower the liquid level in the tank. The microbubble generator according to claim 2 is configured as such.

4. The electrode cover is provided so as to cover the second liquid level electrode among the one or more liquid level electrodes. The microbubble generator according to claim 3 is configured as such.

5. The one or more liquid level electrodes include only a third liquid level electrode capable of detecting whether the liquid level in the tank is equal to or higher than a third liquid level. The electrode cover is provided so as to cover the third liquid level electrode. The lower limit liquid level is the third liquid level. In the microbubble generation operation, when the control device detects that the liquid level in the tank is lower than the lower limit liquid level and stops the gas introduction operation, the control device maintains the state in which the gas introduction operation is stopped until a predetermined time elapses after the gas introduction operation is stopped, and starts the gas introduction operation after the predetermined time elapses. The microbubble generator according to claim 2 is configured as such.

6. The third liquid level is located at a position higher than the lower end of the mixing case. The lower end of the electrode cover is located at a position lower than the lower end of the mixing case. The microbubble generator according to claim 5 is configured as such.

7. In the microbubble generation operation, when the gas introduction operation is executed during the pressurized liquid supply operation, the control device is configured to interrupt the pressurized liquid supply operation at the start of the gas introduction operation and resume the interrupted pressurized liquid supply operation at the stop of the gas introduction operation. The microbubble generator according to any one of claims 2 to 6.

8. In the microbubble generation operation, when the gas introduction operation is executed during the pressurized liquid supply operation, the control device is configured to execute the gas introduction operation without interrupting the pressurized liquid supply operation. The microbubble generator according to any one of claims 2 to 6.

9. The electrode cover is integrally formed seamlessly with a part of the mixing case. The microbubble generator according to any one of claims 1 to 8.

10. The liquid is water, The liquid tank is a bathtub used by a user for bathing. The microbubble generator according to any one of claims 1 to 9.

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