Microbubble generation system

Abstract

In a microbubble generation system where the microbubble generation circuit and the reheating circuit do not share a flow path, this invention provides a technology that allows the pressurized tank to be cleaned with clean water. [Solution] The microbubble generation system comprises a microbubble generation circuit equipped with a pump, a pressurized tank, and a microbubble generation unit, a water supply channel, and a gas introduction mechanism. The water flow path in the microbubble generation circuit does not overlap with the water flow path in the reheating circuit for reheating the bathtub water. The microbubble generation circuit defines a first flow path that sends bathtub water to the bathtub via the pump, pressurized tank, and microbubble generation unit, and a second flow path that sends water from the water supply channel to the bathtub via the pressurized tank. The microbubble generation system is capable of performing a microbubble generation operation in which the pump is driven with the first flow path defined in the microbubble generation circuit, and a tank cleaning operation in which the second flow path is defined in the microbubble generation circuit and water from the water supply channel is sent to the pressurized tank.

Description

Technical Field

[0004] , , , , ,

[0001] The technology disclosed in this specification relates to a microbubble generation system.

Background Art

[0002] Patent Document 1 discloses a microbubble generation system including a pump for pumping water, a pressure tank for pressurizing and dissolving gas in water, a microbubble generation unit for precipitating the gas dissolved in water as microbubbles, a microbubble generation circuit connected to a bathtub and provided with the pump, the pressure tank, and the microbubble generation unit, and a gas introduction mechanism for introducing gas into the microbubble generation circuit. The microbubble generation circuit defines a first flow path for sending water from the bathtub through the pump, the pressure tank, and the microbubble generation unit back to the bathtub. The flow path through which water flows in the microbubble generation circuit has a portion in common with the flow path through which water flows in a heating-up circuit for heating up the water in the bathtub.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The pressurized tank through which the bathtub water flows may accumulate dirt (e.g., sebum) contained in the bathtub water. In the microbubble generation system of Patent Document 1, the microbubble generation circuit and the reheating circuit share a flow path, so when water from the water source (i.e., clean water) flows into the reheating circuit, that water also flows into the pressurized tank provided in the microbubble generation circuit. This allows the pressurized tank to be cleaned. However, the microbubble generation circuit and the reheating circuit may not share a flow path. In this case, even if water from the water source flows into the reheating circuit, that water does not flow into the microbubble generation circuit, so the pressurized tank cannot be cleaned with clean water. This specification provides a technology that enables the pressurized tank to be cleaned with clean water in a microbubble generation system in which the microbubble generation circuit and the reheating circuit do not share a flow path. [Means for solving the problem]

[0005] In a first aspect of this technology, the microbubble generation system may include a pump for pumping water, a pressurized tank for dissolving gas in water under pressure, a microbubble generation unit for precipitating the gas dissolved in water as microbubbles, a microbubble generation circuit connected to a bathtub and equipped with the pump, the pressurized tank, and the microbubble generation unit, a water supply channel through which water supplied from a water source flows and whose downstream end is connected to the middle of the microbubble generation circuit, and a gas introduction mechanism for introducing gas into the microbubble generation circuit. The water flow path in the microbubble generation circuit does not have to have a portion in common with the water flow path in the reheating circuit for reheating the water in the bathtub. The microbubble generation circuit may define a first flow path that sends water from the bathtub to the bathtub via the pump, the pressurized tank, and the microbubble generation unit, and a second flow path that sends water from the water supply channel to the bathtub via the pressurized tank. The microbubble generation system may be configured to perform a microbubble generation operation, which supplies water containing microbubbles to the bathtub by driving the pump with the first flow path defined in the microbubble generation circuit, and a tank cleaning operation, which cleans the pressurized tank by defining a second flow path in the microbubble generation circuit and flowing water from the water supply channel to the pressurized tank.

[0006] With the above configuration, the microbubble generation system can circulate water from the water source (i.e., clean water) into the pressurized tank by performing a tank cleaning operation. This allows the pressurized tank to be cleaned with clean water. Furthermore, with the above configuration, the microbubble generation system can supply the microbubbles generated in the microbubble generation unit to the bathtub by performing a microbubble generation operation.

[0007] In a second aspect of this technology, the microbubble generation system may further include a cistern in the first aspect, which includes a reservoir provided in the water supply channel for storing water supplied from the water source in an open state to the atmosphere, and an overflow channel for discharging water that overflows from the reservoir. The second channel may be a channel for sending water from the water supply channel to the bathtub via the pump and the pressurized tank.

[0008] When a cistern is installed in the water supply channel to prevent backflow of water to the water source, a pump is required to draw water from the reservoir. With the above configuration, the pump installed for performing the microbubble generation operation can also be used as a pump to draw water from the reservoir. Therefore, there is no need to install a separate pump to draw water from the reservoir, and the number of parts in the microbubble generation system can be reduced.

[0009] In a third aspect of this technology, in the first or second aspect described above, the gas introduction mechanism may be switchable between an ON state in which gas is introduced into the microbubble generation circuit and an OFF state in which gas is not introduced into the microbubble generation circuit. The microbubble generation system may further include a water level electrode provided in the pressurized tank for detecting the water level in the pressurized tank. The microbubble generation system may be configured to switch the gas introduction mechanism between the ON state and the OFF state according to the water level in the pressurized tank detected by the water level electrode.

[0010] If dirt adheres to the water level electrode, detection failure may occur. With the above configuration, the water level electrode installed in the pressurized tank can be cleaned by flowing water from the water source (i.e., clean water) into the pressurized tank. This prevents dirt from adhering to the water level electrode, and thus prevents detection failures from occurring.

[0011] In a fourth aspect of this technology, in any one of the first to third aspects described above, the microbubble generation circuit may include a first switching valve, a second switching valve, a first bathtub passage having one end connected to the first switching valve and the other end connected to the bathtub, a second bathtub passage having one end connected to the second switching valve and the other end connected to the bathtub, a tank supply passage having one end connected to the first switching valve and the other end connected to the outlet of the pressurized tank, a tank return passage having one end connected to the second switching valve and the other end connected to the inlet of the pressurized tank, a connecting passage having one end connected to the first switching valve and the other end connected to the second switching valve, and a return passage having one end connected in the middle of the connecting passage and the other end connected in the middle of the tank return passage. The first switching valve may be configured to switch the flow state of water between one end of the first bathtub passage, one end of the tank supply passage, and one end of the connecting passage. The second switching valve may be configured to switch the flow state of water between one end of the second bathtub passage, one end of the tank return passage, and the other end of the connecting passage. The pump may be provided in the return passage. The microbubble generating unit may be provided in the first bathtub passage. The downstream end of the water supply passage may be connected in the middle of the return passage. The microbubble generating system may further include a third switching valve that switches between a state that allows water supply from the water supply passage to the return passage and a state that prohibits it.

[0012] With the above configuration, when water supply from the water supply channel to the microbubble generation circuit is unnecessary (for example, when performing microbubble generation operation), the third switching valve can be made to prohibit the supply of water from the water supply channel to the microbubble generation circuit. This suppresses the unnecessary consumption of water from the water source.

[0013] In a fifth aspect of this technology, in the fourth aspect described above, the third switching valve may be provided at a water supply point to which the downstream end of the water supply channel is connected, and the supply channel may be divided into a first supply channel upstream of the water supply point and a second supply channel downstream of the water supply point. The third switching valve may be configured to switch the flow state of water between the downstream end of the first supply channel, the upstream end of the second supply channel, and the downstream end of the water supply channel. The pump may be provided in the second supply channel. When the microbubble generation system defines the first flow path in the microbubble generation circuit, the third switching valve may be configured to allow water flow at the downstream end of the first supply channel, allow water flow at the upstream end of the second supply channel, and prohibit water flow at the downstream end of the water supply channel. In the case where the microbubble generation system defines the second flow path in the microbubble generation circuit, the third switching valve may be configured to prohibit the flow of water at the downstream end of the first supply path, allow the flow of water at the upstream end of the second supply path, and allow the flow of water at the downstream end of the water supply path.

[0014] If a third switching valve is not installed at the water supply point (i.e., the point where the downstream end of the water supply channel is connected in the distribution channel), the pump will draw in not only water from the water supply channel but also water from the first distribution channel during the tank cleaning operation. In this case, the water flow rate from the water supply channel to the microbubble generation circuit (i.e., the flow rate of clean water supplied to the microbubble generation circuit) will decrease, and the cleaning effect of the pressurized tank may be weakened. In contrast, with the above configuration, during the tank cleaning operation, the third switching valve prevents water from the first distribution channel from flowing into the second distribution channel, thus preventing the pump from drawing in water from the first distribution channel. This increases the water flow rate from the water supply channel to the microbubble generation circuit (i.e., the flow rate of clean water supplied to the microbubble generation circuit), thereby enhancing the cleaning effect of the pressurized tank.

[0015] In a sixth aspect of this technology, in the fourth aspect described above, the third switching valve may be provided at a water supply point to which the downstream end of the water supply channel is connected, and the supply channel may be divided into a first supply channel upstream of the water supply point and a second supply channel downstream of the water supply point. The third switching valve may be configured to switch the flow state of water between the downstream end of the first supply channel, the upstream end of the second supply channel, and the downstream end of the water supply channel. The pump may be provided in the second supply channel. The microbubble generation system may also have a third flow path defined in the microbubble generation circuit, which allows the second switching valve to allow water to flow at one end of the second bathtub passage, to allow water to flow at one end of the tank return passage, and to allow water to flow at the other end of the connecting passage, and allows the third switching valve to allow water to flow at the downstream end of the first return passage, to allow water to flow at the upstream end of the second return passage, and to allow water to flow at the downstream end of the water supply passage, thereby causing water from the water supply passage to flow into the second switching valve via the third switching valve and the second return passage, a portion of the water flowing into the second switching valve to be sent to the bathtub via the second bathtub passage, and the remainder of the water flowing into the second switching valve to flow back into the second switching valve via the connecting passage, the first return passage, the third switching valve, and the second return passage. The microbubble generation system may be configured to further perform a return path cleaning operation, which cleans the return path, by driving the pump with the third flow path defined in the microbubble generation circuit.

[0016] With the above configuration, the microbubble generation system can circulate water from the water source throughout the entire microbubble generation circuit by performing tank cleaning and supply path cleaning operations. This allows the entire microbubble generation circuit to be cleaned with clean water. [Brief explanation of the drawing]

[0017] [Figure 1] This diagram schematically shows the configuration of the bath system 2 according to the embodiment. [Figure 2]It is a diagram schematically showing the flow of water when the hot water filling operation is executed in the bathtub system 2 according to the embodiment. [Figure 3] It is a diagram schematically showing the flow of water when the reheating operation is executed in the bathtub system 2 according to the embodiment. [Figure 4] It is a diagram schematically showing the flow of water when the air introduction step of the microbubble generation operation is executed in the bathtub system 2 according to the embodiment. [Figure 5] It is a diagram schematically showing the flow of water when the microbubble generation step of the microbubble generation operation is executed in the bathtub system 2 according to the embodiment. [Figure 6] It is a diagram schematically showing the flow of water when the cold water relaxation operation is executed in the bathtub system 2 according to the embodiment. [Figure 7] It is a diagram schematically showing the flow of water when the return path cleaning step of the microbubble generation circuit cleaning operation is executed in the bathtub system 2 according to the embodiment. [Figure 8] It is a diagram schematically showing the flow of water when the tank cleaning step of the microbubble generation circuit cleaning operation is executed in the bathtub system 2 according to the embodiment. [Figure 9] It is a diagram schematically showing the flow of water when the tank cleaning step of the microbubble generation circuit cleaning operation is executed in the bathtub system 2 according to the modification example. [Figure 10] It is a diagram schematically showing the flow of water when the tank cleaning step of the microbubble generation circuit cleaning operation is executed in the bathtub system 2 according to another modification example. [Figure 11] It is a diagram schematically showing the configuration of the bathtub system 2 according to yet another modification example.

Mode for Carrying Out the Invention

[0018] (Example) As shown in FIG. 1, the bath system 2 includes a heat source unit 10, an air dissolution unit 50, and a bathtub adapter 150. The bath system 2 can heat the water supplied from a water supply source 202 such as a water supply and supply the heated water at a desired temperature to a kitchen sink 204 installed in a kitchen or the like or a bathtub 206 installed in a bathroom. The bath system 2 can circulate and heat the water in the bathtub 206. Further, the bath system 2 can generate fine bubbles in the water in the bathtub 206 used by a user for bathing.

[0019] (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 distribution path 16, a hot water outlet path 18, a heat source bypass path 20, a bypass servo 22, a first hot water injection path 24, a water filling valve 26, a water volume sensor 28, a supplementary heating forward path 30, a supplementary heating return path 32, a circulation pump 34, a water flow switch 36, and a heat source controller 38.

[0020] The upstream end of the water distribution path 16 is connected to the water supply source 202. The downstream end of the water distribution 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. The downstream end of the hot water outlet path 18 is connected to the kitchen sink 204. The first heat source machine 12 heats water, for example, by combustion of gas. The first heat source machine 12 heats the water flowing in from the water distribution path 16 and sends out the heated water to the hot water outlet path 18.

[0021] The upstream end of the heat source bypass 20 is connected to the water distribution channel 16. The downstream end of the heat source bypass 20 is connected to the hot water outlet channel 18. A bypass servo 22 is installed at the point where the heat source bypass 20 connects to the water distribution channel 16. By adjusting the opening degree of the built-in valve body, the bypass servo 22 can adjust the ratio of the flow rate of water flowing from the water distribution channel 16 to the hot water outlet channel 18 via the first heat source unit 12 and the flow rate of water flowing from the water distribution channel 16 to the hot water outlet channel 18 via the heat source bypass 20. By adjusting the opening degree of the bypass servo 22, the hot water outlet channel 18 downstream of the point where the heat source bypass 20 connects is supplied with water that has been mixed in a desired ratio with high-temperature water flowing from the first heat source unit 12 and low-temperature water flowing from the heat source bypass 20, and is heated to a desired temperature. A hot water outlet temperature thermistor 18a is provided in the hot water outlet channel 18 downstream of the point where the heat source bypass 20 connects to detect the temperature of the water in the hot water outlet channel 18.

[0022] The upstream end of the first hot water supply channel 24 is connected to the outlet channel 18 downstream of the point where the heat source bypass channel 20 is connected. The downstream end of the first hot water supply channel 24 is connected to the reheating return channel 32. A hot water supply valve 26 is provided in the first hot water supply channel 24 and opens and closes the first hot water supply channel 24. The hot water supply valve 26 is normally closed. A water volume sensor 28 is provided in the first hot water supply channel 24 and detects the amount of water flowing through the first hot water supply channel 24.

[0023] The upstream end of the reheating return path 32 is connected to the third adapter passage 156 of the bathtub adapter 150. The downstream end of the reheating return path 32 is connected to the second heat source unit 14. The upstream end of the reheating supply path 30 is also connected to the second heat source unit 14. The downstream end of the reheating supply path 30 is connected to the fourth adapter passage 158 of the bathtub adapter 150. The second heat source unit 14 heats the water, for example, by the combustion of gas. The second heat source unit 14 heats the water flowing in from the reheating return path 32 and sends the heated water to the reheating supply path 30. The reheating return path 32 is equipped with a reheating return path thermistor 32a for detecting the water temperature in the reheating return path 32. The reheating supply path 30 is equipped with a reheating supply path thermistor 30a for detecting the water temperature in the reheating supply path 30.

[0024] The circulation pump 34 is located in the reheating return path 32 downstream of the connection point of the first hot water supply path 24, and sends the water from the reheating return path 32 toward the second heat source unit 14. The water flow switch 36 is located between the circulation pump 34 and the second heat source unit 14 in the reheating return path 32, and detects whether or not water is flowing in the reheating return path 32.

[0025] The heat source controller 38 includes a CPU, ROM, RAM, etc. The heat source controller 38 controls the operation of each component of the heat source unit 10. The heat source controller 38 is configured to communicate with a user-operable remote control (not shown). The user can input various settings such as the set temperature and set water volume for the hot water filling operation described later, and can also instruct the start and end of the hot water filling operation via the remote control.

[0026] (Configuration of the air dissolution unit 50) The air dissolution unit 50 includes a pressurized tank 52, a gas introduction mechanism 54, a return pump 56, a first pressurized pump 58, a second pressurized pump 60, a first three-way valve 62, a second three-way valve 64, a third three-way valve 66, a tank water supply valve 68, a first check valve 70, a water flow switch 72, a first air dissolution passage 82, a second air dissolution passage 84, a tank forward passage 86, a tank return passage 88, a connecting passage 90, a first return passage 92, and a second return passage 94. In this embodiment, the first return passage 92 and the second return passage 94 are collectively referred to as return passages 92 and 94.

[0027] The first air dissolution passage 82 has one end connected to the first three-way valve 62 and the other end connected to the first adapter passage 152 of the bathtub adapter 150. The second air dissolution passage 84 has one end connected to the second three-way valve 64 and the other end connected to the second adapter passage 154 of the bathtub adapter 150. The tank supply passage 86 has one end connected to the first three-way valve 62 and the other end connected to the outlet 52b of the pressurized tank 52. The tank return passage 88 has one end connected to the second three-way valve 64 and the other end connected to the inlet 52a of the pressurized tank 52. The connecting passage 90 has one end connected to the first three-way valve 62 and the other end connected to the second three-way valve 64. The first return passage 92 has its upstream end connected in the middle of the connecting passage 90 and its downstream end connected to the third three-way valve 66. The second supply line 94 has its upstream end connected to the third three-way valve 66 and its downstream end connected to the middle of the tank return line 88.

[0028] The first three-way valve 62 switches the flow state of water between one end of the first air dissolution passage 82, one end of the tank supply passage 86, and one end of the connecting passage 90 by switching the position of the valve body inside it. In this embodiment, the position of the valve body of the first three-way valve 62 is switched between a first valve position (see Figures 1, 2, 3, 5, and 7) that allows water flow at one end of the first air dissolution passage 82, allows water flow at one end of the tank supply passage 86, and prohibits water flow at one end of the connecting passage 90; a second valve position (see Figures 6 and 8) that allows water flow at one end of the first air dissolution passage 82, allows water flow at one end of the tank supply passage 86, and allows water flow at one end of the connecting passage 90; and a third valve position (see Figure 4) that prohibits water flow at one end of the first air dissolution passage 82, allows water flow at one end of the tank supply passage 86, and allows water flow at one end of the connecting passage 90.

[0029] The second three-way valve 64 switches the flow state of water between one end of the second air dissolution passage 84, one end of the tank return passage 88, and the other end of the connecting passage 90 by switching the position of the valve body it contains. In this embodiment, the position of the valve body of the second three-way valve 64 can be switched between a fourth valve position (see Figures 1, 2, 3, 5, and 8) that allows water to flow at one end of the second air dissolution passage 84, prohibits water flow at one end of the tank return passage 88, and allows water to flow at the other end of the connecting passage 90; a fifth valve position (see Figures 4 and 6) that allows water to flow at one end of the second air dissolution passage 84, prohibits water flow at one end of the tank return passage 88, and prohibits water flow at the other end of the connecting passage 90; and a sixth valve position (see Figure 7) that allows water to flow at one end of the second air dissolution passage 84, prohibits water flow at one end of the tank return passage 88, and allows water to flow at the other end of the connecting passage 90.

[0030] The third three-way valve 66 switches the flow state of water between the downstream end of the first supply channel 92, the upstream end of the second supply channel 94, and the downstream end of the intake channel 114 (details will be described later) by switching the position of the valve body it contains. In this embodiment, the position of the valve body of the third three-way valve 66 can be switched between the following positions: a seventh valve position (see Figures 1, 2, 3, 4, 5, and 6) that allows water flow at the downstream end of the first supply channel 92, allows water flow at the upstream end of the second supply channel 94, and prohibits water flow at the downstream end of the intake channel 114; an eighth valve position (see Figure 8) that prohibits water flow at the downstream end of the first supply channel 92, allows water flow at the upstream end of the second supply channel 94, and allows water flow at the downstream end of the intake channel 114; and a ninth valve position (see Figure 7) that allows water flow at the downstream end of the first supply channel 92, allows water flow at the upstream end of the second supply channel 94, and allows water flow at the downstream end of the intake channel 114.

[0031] The pressurized tank 52 can store water inside. The inlet 52a of the pressurized tank 52 is located on the upper side of the pressurized tank 52. The outlet 52b of the pressurized tank 52 is located on the bottom of the pressurized tank 52. Inside the pressurized tank 52, a low-level electrode 102a, a high-level electrode 102b, and a ground electrode 102c are installed to detect the water level inside the pressurized tank 52. The water level detected by the low-level electrode 102a (hereinafter also referred to as the lower limit water level) is lower than the water level detected by the high-level electrode 102b (hereinafter also referred to as the upper limit water level). When the low-level electrode 102a and the high-level electrode 102b each come into contact with the water surface stored in the pressurized tank 52, a current flows between them and the ground electrode 102c, and a water level detection signal is output to the air dissolution controller 100. The pressurized tank 52 is used to produce air-dissolved water by pressurizing and dissolving air in water.

[0032] The gas introduction mechanism 54 includes an air introduction passage 104 and an air introduction valve 106. One end of the air introduction passage 104 is open to the atmosphere. The other end of the air introduction passage 104 is connected to the top of the pressurized tank 52. The air introduction passage 104 introduces air into the pressurized tank 52. The air introduction valve 106 is provided in the air introduction passage 104 and opens and closes the air introduction passage 104. The air introduction valve 106 is normally closed.

[0033] The return pump 56 is located in the second return line 94. The return pump 56 sends the water from the second return line 94 towards the tank return line 88.

[0034] The water flow switch 72 is located in the second return path 94 downstream of the return pump 56. The water flow switch 72 detects whether or not water is flowing in the second return path 94.

[0035] The tank water supply valve 68 is located in the tank return path 88, between the point where the second supply path 94 connects and the pressurized tank 52. The tank water supply valve 68 opens and closes the tank return path 88. The tank water supply valve 68 is normally closed.

[0036] The first pressurizing pump 58 and the second pressurizing pump 60 are located in the tank return path 88, between the tank water supply valve 68 and the pressurized tank 52. The first pressurizing pump 58 and the second pressurizing pump 60 pressurize the water in the tank return path 88 and send it towards the pressurized tank 52. In the tank return path 88, the first pressurizing pump 58 is located upstream of the second pressurizing pump 60.

[0037] The first check valve 70 is located in the tank supply passage 86. The first check valve 70 allows water to flow from the pressurized tank 52 toward the first three-way valve 62, and prevents water from flowing from the first three-way valve 62 toward the pressurized tank 52.

[0038] The air dissolution unit 50 further includes a water supply channel 112, a water intake channel 114, a cistern 116, a second check valve 118, a water volume servo 120, a water volume sensor 122, and a water supply valve 124.

[0039] The upstream end of the supplementary water channel 112 is connected to the outlet channel 18. The downstream end of the supplementary water channel 112 is connected to the inlet 126a of the reservoir 126 of the cistern 116. The upstream end of the intake channel 114 is connected to the outlet 126b of the reservoir 126 of the cistern 116. The downstream end of the intake channel 114 is connected to the third three-way valve 66.

[0040] The water supply channel 112 is equipped with, in order from upstream to downstream, a second check valve 118, a water flow servo 120, a water flow sensor 122, and a water supply valve 124. The second check valve 118 allows water to flow from upstream to downstream in the water supply channel 112 and prohibits water to flow from downstream to upstream. The water flow servo 120 adjusts the flow rate of water flowing into the water supply channel 112 by adjusting the opening degree of its built-in valve body. The water flow sensor 122 detects the amount of water flowing into the water supply channel 112. The water supply valve 124 opens and closes the water supply channel 112. The water supply valve 124 is normally closed.

[0041] The cistern 116 includes a water reservoir 126 for storing water. The inlet 126a of the water reservoir 126 is located on the upper side of the water reservoir 126. The outlet 126b of the water reservoir 126 is located on the bottom of the water reservoir 126. The water reservoir 126 is open to the atmosphere. The water reservoir 126 is equipped with a water level sensor (not shown) for detecting the water level inside. In this embodiment, when the water level detected by the water level sensor falls below a predetermined level, the water supply valve 124 is opened, and water is supplied to the water reservoir 126 via the water supply channel 112. In this way, the water reservoir 126 is supplied with water as needed. The cistern 116 also further includes an overflow channel 128 for discharging water that overflows from the water reservoir 126. The upstream end of the overflow channel 128 is connected to the inside of the water reservoir 126 via an overflow port 130 that opens into the inside of the water reservoir 126. The downstream end of the overflow channel 128 is connected to a drainage point (not shown). In the vertical direction, the lower end of the overflow port 130 is positioned below the lower end of the inlet 126a of the water reservoir 126. If the water level inside the water reservoir 126 reaches the height of the lower end of the overflow port 130, the water in the water reservoir 126 flows into the overflow port 130. The water that flows into the overflow port 130 is discharged to the drainage point via the overflow channel 128. This prevents the water in the water reservoir 126 from flowing back towards the water supply channel 112. In other words, the cistern 116 functions as a backflow prevention device that prevents the water in the water reservoir 126 (including water downstream of the water reservoir 126) from flowing back to the water supply source 202 via the water supply channel 112 by separating the water supply channel 112 from the water in the water reservoir 126.

[0042] The air dissolution unit 50 further includes an air dissolution controller 100. The air dissolution controller 100 includes a CPU, ROM, RAM, etc. The air dissolution controller 100 controls the operation of each component of the air dissolution unit 50. The air dissolution controller 100 is configured to communicate with a user-operable remote control (not shown). The user can instruct the air dissolution controller 100 to start or stop the microbubble generation operation, which will be described later, via the remote control.

[0043] (Configuration of Bathtub Adapter 150) The bathtub adapter 150 comprises a first adapter passage 152, a second adapter passage 154, a third adapter passage 156, a fourth adapter passage 158, and a microbubble generating nozzle 160. The first adapter passage 152 connects the other end of the first air dissolution passage 82 to the inside of the bathtub 206. The second adapter passage 154 connects the other end of the second air dissolution passage 84 to the inside of the bathtub 206. The third adapter passage 156 connects the upstream end of the reheating return path 32 to the inside of the bathtub 206. The fourth adapter passage 158 connects the downstream end of the reheating forward path 30 to the inside of the bathtub 206. On the outer surface of the bathtub adapter 150, the fourth adapter passage 158 opens downward. This prevents the water sent to the bathtub 206 via the fourth adapter passage 158 (for example, water heated by the second heat source unit 14 during reheating operation) from being forcefully discharged towards the user while they are bathing. In addition, a microbubble generating nozzle 160 is provided in the first adapter passage 152. The microbubble generating nozzle 160 is equipped with a venturi (not shown) and reduces the pressure of the water passing through the microbubble generating nozzle 160, causing the gas dissolved in the water to precipitate as microbubbles.

[0044] Next, we will explain the hot water filling operation and reheating operation performed by the heat source controller 38.

[0045] (Water filling operation: Figure 2) The bath filling operation starts when the user instructs the user to start the bath filling operation using the remote control. Alternatively, the bath filling operation may start when the user sets the start time for the bath filling operation using the remote control, and the heat source controller 38 determines that the start time for the bath filling operation has arrived. When the bath filling operation starts, the heat source controller 38 opens the bath filling valve 26 and starts heating with the first heat source unit 12. As a result, as shown in Figure 2, water heated to the set temperature flows from the outlet passage 18 through the first hot water supply passage 24 into the reheating return passage 32. A portion of the water that flows into the reheating return passage 32 flows toward the upstream end of the reheating return passage 32 and flows into the bathtub 206 via the third adapter passage 156. The remaining water that flows into the reheating return passage 32 flows toward the downstream end of the reheating return passage 32 and flows into the second heat source unit 14. The water flowing into the second heat source unit 14 flows into the bathtub 206 via the reheating supply path 30 and the fourth adapter passage 158. At this time, the second heat source unit 14 does not heat the water and simply functions as a water flow path. The heat source controller 38 waits until the cumulative water volume detected by the water volume sensor 28 reaches the set water volume for the bathtub filling operation. The cumulative water volume here refers to the cumulative water volume detected by the water volume sensor 28 since the start of the bathtub filling operation. When the cumulative water volume reaches the set water volume, the heat source controller 38 closes the bathtub filling valve 26 and terminates the heating of the water by the first heat source unit 12. After that, the heat source controller 38 terminates the bathtub filling operation.

[0046] (Reheating operation: Figure 3) The reheating operation starts when the user instructs the reheating operation to start using the remote control. Alternatively, the reheating operation may start after the first heat source unit 12 has finished heating the water during the bath filling operation, if the heat source controller 38 determines that the temperature detected by the reheating return path thermistor 32a is below the set temperature. When the reheating operation starts, the heat source controller 38 drives the circulation pump 34 and starts heating the water with the second heat source unit 14. As a result, as shown in Figure 3, the water in the bathtub 206 is sent to the second heat source unit 14 via the third adapter passage 156 and the reheating return path 32. The water heated by the second heat source unit 14 is returned to the bathtub 206 via the reheating outbound path 30 and the fourth adapter passage 158. When the temperature detected by the reheat return path thermistor 32a exceeds the set temperature, the heat source controller 38 stops the circulation pump 34 and terminates the heating of water by the second heat source unit 14. After that, the heat source controller 38 terminates the reheat operation.

[0047] Next, we will describe the microbubble generation operation, chilled water relaxation operation, and microbubble generation circuit cleaning operation performed by the air dissolution controller 100.

[0048] (Microbubble generation operation) The microbubble generation operation is initiated when the user commands the start of the microbubble generation operation using the remote control. The microbubble generation operation includes an air introduction step and a microbubble generation step. The air introduction step and the microbubble generation step are performed alternately based on the water levels detected by the low water level electrode 102a and the high water level electrode 102b.

[0049] (Air introduction process: Figure 4) The air introduction process is performed at the start of the microbubble generation operation and after the completion of the microbubble generation process, and is carried out until the water level in the pressurized tank 52 falls below the lower limit water level. When the air introduction process is started, the air dissolution controller 100 sets the valve body of the first three-way valve 62 to the third valve position, the valve body of the second three-way valve 64 to the fifth valve position, and the valve body of the third three-way valve 66 to the seventh valve position. The air dissolution controller 100 also opens the air introduction valve 106 and closes the tank water supply valve 68, and then drives the return pump 56. As a result, as shown in Figure 4, the water in the pressurized tank 52 is drawn into the return pump 56 via the tank forward passage 86, the first three-way valve 62, the connecting passage 90, the first return passage 92, the third three-way valve 66, and the second return passage 94. Furthermore, the water discharged by the return pump 56 flows into the bathtub 206 via the second return passage 94, the tank return passage 88, the second three-way valve 64, the second air dissolution passage 84, and the second adapter passage 154. As the water in the pressurized tank 52 is discharged into the bathtub 206, air is introduced into the pressurized tank 52 via the air introduction passage 104. During the air introduction process, the water level in the pressurized tank 52 decreases.

[0050] (Microbubble generation process: Figure 5) The microbubble generation process is started after the air introduction process is completed and continues until the water level in the pressurized tank 52 reaches or exceeds the upper limit. When the microbubble generation process is started, the air dissolution controller 100 sets the valve body of the first three-way valve 62 to the first valve position, the valve body of the second three-way valve 64 to the fourth valve position, and the valve body of the third three-way valve 66 to the seventh valve position. The air dissolution controller 100 also closes the air introduction valve 106, opens the tank water supply valve 68, and drives the return pump 56, the first pressurized pump 58, and the second pressurized pump 60. As a result, as shown in Figure 5, water in the bathtub 206 is supplied to the pressurized tank 52 via the second adapter passage 154, the second air dissolution passage 84, the second three-way valve 64, the connecting passage 90, the first return passage 92, the third three-way valve 66, the second return passage 94, and the tank return passage 88. At this time, water pressurized by the first pressurizing pump 58 and the second pressurizing pump 60 is supplied from the tank return line 88 to the pressurizing tank 52. As a result, air is pressurized and dissolved into the water inside the pressurizing tank 52. The water with pressurized and dissolved air is then returned from the pressurizing tank 52 to the bathtub 206 via the tank forward line 86, the first three-way valve 62, the first air dissolution passage 82, and the first adapter passage 152. As the water with pressurized and dissolved air passes through the microbubble generating nozzle 160 provided in the first adapter passage 152, the pressure is reduced to below atmospheric pressure due to the Venturi effect. At this time, microbubbles are generated in the water with pressurized and dissolved air. As a result, in the microbubble generation process, water containing microbubbles is supplied to the bathtub 206. In the microbubble generation process, the flow rate of water supplied from the bathtub 206 to the pressurizing tank 52 is greater than the flow rate of water supplied from the pressurizing tank 52 to the bathtub 206, so the water level in the pressurizing tank 52 rises.

[0051] When the number of times the air introduction process and the microbubble generation process are executed reaches a predetermined number of repetitions (for example, 5 times), the air dissolution controller 100 stops the return pump 56, the first pressurizing pump 58, and the second pressurizing pump 60, and closes the tank water supply valve 68. After that, the air dissolution controller 100 terminates the microbubble generation operation.

[0052] (Chilled water mitigation operation: Figure 6) The chilled water relaxation operation is performed prior to the microbubble generation operation when an instruction to perform the microbubble generation operation is given after a predetermined time (for example, 600 seconds) has elapsed since the last completion of the microbubble generation operation. When the chilled water relaxation operation is started, the air dissolution controller 100 sets the position of the valve body of the first three-way valve 62 to the second valve position, the position of the valve body of the second three-way valve 64 to the fifth valve position, and the position of the valve body of the third three-way valve 66 to the seventh valve position. The air dissolution controller 100 also drives the return pump 56 with the air introduction valve 106 and the tank water supply valve 68 closed. As a result, as shown in Figure 6, the water in the bathtub 206 is drawn into the return pump 56 via the first adapter passage 152, the first air dissolution passage 82, the first three-way valve 62, the connecting passage 90, the first return passage 92, the third three-way valve 66, and the second return passage 94. Furthermore, the water discharged by the return pump 56 flows into the bathtub 206 via the second return passage 94, the tank return passage 88, the second three-way valve 64, the second air dissolution passage 84, and the second adapter passage 154. When the time elapsed since the start of the chilled water relaxation operation reaches a predetermined time (for example, 30 seconds), the air dissolution controller 100 stops the return pump 56 and ends the chilled water relaxation operation. The chilled water relaxation operation replaces the water in each passage with the water in the bathtub 206. This prevents the accumulation of low-temperature water in each passage, thus preventing the supply of low-temperature water to the bathtub 206 at the start of the subsequent microbubble generation operation.

[0053] (Microbubble generation circuit cleaning operation) The microbubble generation circuit cleaning operation is started when the microbubble generation operation is completed. Alternatively, the microbubble generation circuit cleaning operation is started when the user instructs the user to start the microbubble generation circuit cleaning operation using the remote control. Once the microbubble generation circuit cleaning operation is started, the transport path cleaning process and the tank cleaning process are executed in order.

[0054] (Transportation path cleaning process: Figure 7) When the return path cleaning process is started, the air dissolution controller 100 sets the position of the valve body of the first three-way valve 62 to the first valve position, the position of the valve body of the second three-way valve 64 to the sixth valve position, and the position of the valve body of the third three-way valve 66 to the ninth valve position. The air dissolution controller 100 also drives the return pump 56. As a result, as shown in Figure 7, the water stored in the reservoir 126 is drawn into the return pump 56 via the intake channel 114, the third three-way valve 66, and the second return path 94. The water discharged by the return pump 56 flows into the second three-way valve 64 via the second return path 94 and the tank return path 88. A portion of the water that flows into the second three-way valve 64 flows into the bathtub 206 via the second air dissolution passage 84 and the second adapter passage 154. The remaining water that has flowed into the second three-way valve 64 is drawn back into the return pump 56 via the connecting passage 90, the first return passage 92, the third three-way valve 66, and the second return passage 94. In this process, the clean water stored in the water reservoir 126 passes through the entirety of the return passages 92 and 94 before being discharged into the bathtub 206. This washes away dirt (e.g., sebum) adhering to the return passages 92 and 94. It also washes away dirt adhering to the connecting passage 90, the tank return passage 88, and the second air dissolution passage 84. When the time elapsed since the start of the return passage cleaning process reaches a predetermined time (e.g., 20 seconds), the air dissolution controller 100 stops the return pump 56 and closes the tank water supply valve 68. After that, the air dissolution controller 100 ends the return passage cleaning process.

[0055] (Tank cleaning process: Figure 8) When the tank cleaning process begins, the air dissolution controller 100 sets the valve body of the first three-way valve 62 to the second valve position, the valve body of the second three-way valve 64 to the fourth valve position, and the valve body of the third three-way valve 66 to the eighth valve position. The air dissolution controller 100 also opens the tank water supply valve 68 and drives the return pump 56. As a result, as shown in Figure 8, the water stored in the reservoir 126 is drawn into the return pump 56 via the intake channel 114, the third three-way valve 66, and the second return channel 94. The water discharged by the return pump 56 flows into the first three-way valve 62 via the second return channel 94, the tank return channel 88, the pressurized tank 52, and the tank forward channel 86. A portion of the water flowing into the first three-way valve 62 flows into the bathtub 206 via the first air dissolution passage 82 and the first adapter passage 152. The remaining water flowing into the first three-way valve 62 flows into the bathtub 206 via the connecting passage 90, the second three-way valve 64, the second air dissolution passage 84, and the second adapter passage 154. In this process, clean water stored in the water reservoir 126 is discharged into the bathtub 206 after passing through the pressurized tank 52. This washes away dirt (e.g., sebum) attached to the pressurized tank 52. Dirt attached to the second return passage 94, the tank return passage 88, the tank forward passage 86, the first air dissolution passage 82, the connecting passage 90, and the second air dissolution passage 84 is also washed away. During the tank cleaning process, the first pressurized pump 58 and the second pressurized pump 60 are stopped and simply function as pathways through which water flows. When the time elapsed since the start of the tank cleaning process reaches a predetermined time (for example, 30 seconds), the air dissolution controller 100 stops the return pump 56 and closes the tank water supply valve 68. After that, the air dissolution controller 100 terminates the tank cleaning process. When the tank cleaning process is completed, the microbubble generation circuit cleaning operation also terminates.

[0056] (Correspondence) In this embodiment, the bath system 2 is an example of a "microbubble generation system". The return pump 56 is an example of a "pump". The pressurized tank 52 is an example of a "pressurized tank". The microbubble generation nozzle 160 is an example of a "microbubble generation unit". The circuit consisting of the third adapter passage 156, the reheating return path 32, the reheating forward path 30, and the fourth adapter passage 158 is an example of a "reheating circuit". The circuit consisting of the first three-way valve 62, the second three-way valve 64, the third three-way valve 66, the first air dissolution passage 82, the second air dissolution passage 84, the tank forward path 86, the tank return path 88, the connecting passage 90, the first return path 92, the second return path 94, the first adapter passage 152, and the second adapter passage 154 is an example of a "microbubble generation circuit". The passage consisting of the water supply channel 112 and the water intake channel 114 is an example of a "water supply channel". The gas introduction mechanism 54 is an example of a "gas introduction mechanism". The state in which the air introduction valve 106 is open is an example of the "ON state". The state in which the air introduction valve 106 is closed is an example of the "OFF state". The low water level electrode 102a, the high water level electrode 102b, and the ground electrode 102c are each examples of "water level electrodes". The water reservoir 126 is an example of a "water reservoir". The overflow channel 128 is an example of an "overflow channel". The cistern 116 is an example of a "cistern". The flow path shown in Figure 5 is an example of a "first flow path". The flow path shown in Figure 8, Figure 9, or Figure 10 is an example of a "second flow path". The flow path shown in Figure 7 is an example of a "third flow path". The first three-way valve 62 is an example of a "first switching valve". The second three-way valve 64 is an example of a "second switching valve". The third three-way valve 66 is an example of a "third switching valve". The passage consisting of the first air dissolution passage 82 and the first adapter passage 152 is an example of a "first bathtub passage". The passage consisting of the second air dissolution passage 84 and the second adapter passage 154 is an example of a "second bathtub passage". The tank supply passage 86 is an example of a "tank supply passage". The tank return passage 88 is an example of a "tank return passage". The connecting passage 90 is an example of a "connecting passage". The return passages 92 and 94 are examples of "return passages". The first return passage 92 is an example of a "first return passage". The second return passage 94 is an example of a "second return passage". The tank cleaning process in the microbubble generation circuit cleaning operation is an example of a "tank cleaning operation", and the return passage cleaning process is an example of a "return passage cleaning operation".

[0057] If the reheating circuit and the microbubble generation circuit were to share a flow path, it would be necessary to link the heat source unit 10 and the air dissolution unit 50 via communication. In this embodiment, since the reheating circuit and the microbubble generation circuit do not share a flow path, there is no need to link the heat source unit 10 and the air dissolution unit 50. This improves the compatibility between the heat source unit 10 and the air dissolution unit 50. For example, a heat source unit 10 and an air dissolution unit 50 from different manufacturers can be combined.

[0058] Furthermore, according to this embodiment, by performing a microbubble generation circuit cleaning operation, water from the water supply source 202 (i.e., clean water) can be circulated throughout the entire microbubble generation circuit. This allows the entire microbubble generation circuit to be cleaned with clean water.

[0059] As shown in Figure 7, in the return channel cleaning process of the microbubble generation circuit cleaning operation, a flow path (also called an internal circulation flow path) is formed by the tank return path 88, the second three-way valve 64, the connecting passage 90, the first return channel 92, the third three-way valve 66, and the second return channel 94, which circulate water within the microbubble generation circuit. In the return channel cleaning process, it takes a certain amount of time (for example, 10 seconds) to replace the water in the internal circulation flow path with clean water from the water supply channel. Therefore, if the execution time of the return channel cleaning process is short, the dirt in the internal circulation flow path may not be completely removed, and dirt may remain in the internal circulation flow path. However, in this embodiment, since the tank cleaning process is performed after the return channel cleaning process, even if dirt remains in the internal circulation flow path in the return channel cleaning process, clean water from the water supply channel flows into a part of the internal circulation flow path (the connecting passage 90 and the second return channel 94 in the example of Figure 8) in the subsequent tank cleaning process, and the remaining dirt is washed away. This prevents dirt from remaining throughout the internal circulation channel when the microbubble generation circuit cleaning operation is completed.

[0060] Furthermore, according to this embodiment, by providing the return pump 56 in the second return passage 94, the return pump 56 can perform multiple roles. Specifically, by driving the return pump 56 with the valve body of the third three-way valve 66 in the eighth valve position or the ninth valve position, the return pump 56 provided in the second return passage 94 can draw water stored in the reservoir 126 into the intake passage 114. Also, by driving the return pump 56 with the valve body of the third three-way valve 66 in the seventh valve position, the return pump 56 provided in the second return passage 94 can draw water from the communication passage 90 into the first return passage 92. As a result, the return pump 56 can be shared between each process of the microbubble generation operation, the chilled water relaxation operation, and each process of the microbubble generation circuit cleaning operation. With this configuration, there is no need to separately provide a pump for drawing water stored in the reservoir 126 into the intake channel 114 and a pump for drawing water from the connecting passage 90 into the first supply channel 92, thus reducing the number of pumps provided in the microbubble generation circuit.

[0061] (modified version) The water supply source 202 may be connected to the upstream end of the water supply channel 112 instead of the hot water outlet channel 18. In other words, the water supply source 202 may be connected to the air dissolution unit 50 without going through the heat source unit 10.

[0062] The air dissolution unit 50 does not necessarily have a cistern 116. That is, the upstream end of the intake channel 114 and the downstream end of the supplemental channel 112 may be connected. In this case, during the microbubble generation circuit cleaning operation, instead of driving the return pump 56, the supplemental valve 124 may be opened and water from the water source 202 may be introduced into the air dissolution unit 50 using the water pressure from the water source 202.

[0063] The air dissolution unit 50 may be equipped with an on-off valve for opening and closing the intake channel 114 instead of the third three-way valve 66. This on-off valve may be closed when the microbubble generation circuit cleaning operation is not performed, prohibiting the flow of water through the intake channel 114. This on-off valve may be opened when the microbubble generation circuit cleaning operation is performed, allowing the flow of water through the intake channel 114.

[0064] (See Figure 8) During the tank cleaning process of the microbubble generation circuit cleaning operation, the first pressure pump 58 and / or the second pressure pump 60 may be driven instead of the return pump 56. Alternatively, all of the return pump 56, the first pressure pump 58, and the second pressure pump 60 may be driven. In this case as well, water will flow in the tank cleaning process in the same manner as in Figure 8.

[0065] In the microbubble generation circuit cleaning operation, the air dissolution controller 100 may be configured to perform a return path cleaning process after performing a tank cleaning process.

[0066] The microbubble generation circuit cleaning operation does not necessarily include a return path cleaning process. That is, the air dissolution controller 100 may be configured to perform only a tank cleaning process as the microbubble generation circuit cleaning operation.

[0067] As shown in Figure 9, during the tank cleaning process, the valve body of the first three-way valve 62 may be in the first valve position. In this case, all of the water flowing into the first three-way valve 62 may flow into the bathtub 206 via the first air dissolution passage 82 and the first adapter passage 152.

[0068] As shown in Figure 10, during the tank cleaning process, the valve body of the first three-way valve 62 may be in the third valve position. In this case, all of the water flowing into the first three-way valve 62 may flow into the bathtub 206 via the connecting passage 90, the second three-way valve 64, the second air dissolution passage 84, and the second adapter passage 154.

[0069] As shown in Figure 11, the bathtub adapter 150 may be divided into a bathtub adapter 150a for the heat source unit 10 and a bathtub adapter 150b for the air dissolution unit 50.

[0070] The technical elements described herein or in the drawings demonstrate technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies illustrated herein or in the drawings can achieve multiple objectives simultaneously, and achieving even one of these objectives constitutes technical usefulness in itself. [Explanation of Symbols]

[0071] 2: Bath system, 10: Heat source unit, 12: First heat source unit, 14: Second heat source unit, 16: Water distribution channel, 18: Hot water outlet channel, 18a: Hot water outlet temperature thermistor, 20: Heat source bypass channel, 22: Bypass servo, 24: First hot water supply channel, 26: Hot water filling valve, 28: Water volume sensor, 30: Reheating supply channel, 30a: Reheating supply channel thermistor, 32: Reheating return channel, 32a: Reheating return channel thermistor, 34: Circulation pump, 3 6: Water flow switch, 38: Heat source controller, 50: Air dissolution unit, 52: Pressurized tank, 52a: Inlet, 52b: Outlet, 54: Gas introduction mechanism, 56: Return pump, 58: First pressurized pump, 60: Second pressurized pump, 62: First three-way valve, 64: Second three-way valve, 66: Third three-way valve, 68: Tank water supply valve, 70: First check valve, 72: Water flow switch, 82: First air dissolution passage, 84: Second air dissolution passage Path, 86: Tank supply path, 88: Tank return path, 90: Connecting passage, 92: First supply path, 94: Second supply path, 100: Air dissolution controller, 102a: Low water level electrode, 102b: High water level electrode, 102c: Ground electrode, 104: Air inlet path, 106: Air inlet valve, 112: Water supply path, 114: Water intake path, 116: Cistern, 118: Second check valve, 120: Water volume servo, 122: Water volume sensor, 124: Water supply Valve, 126: Water reservoir, 126a: Inlet, 126b: Outlet, 128: Overflow passage, 130: Overflow outlet, 150: Bathtub adapter, 150a: Bathtub adapter, 150b: Bathtub adapter, 152: First adapter passage, 154: Second adapter passage, 156: Third adapter passage, 158: Fourth adapter passage, 160: Microbubble generating nozzle, 202: Water source, 204: Faucet, 206: Bathtub

Claims

1. A pump that pressurizes water, A pressurized tank for dissolving gas in water under pressure, A microbubble generating unit that precipitates gas dissolved in water as microbubbles, A microbubble generating circuit is connected to the bathtub and includes the pump, the pressurized tank, and the microbubble generating unit. A water supply channel through which water supplied from a water source flows, and whose downstream end is connected to the middle of the microbubble generation circuit, A microbubble generation system comprising a gas introduction mechanism for introducing gas into the microbubble generation circuit, The water flow path in the microbubble generation circuit does not have any common parts with the water flow path in the reheating circuit for reheating the water in the bathtub. The aforementioned microbubble generation circuit is A first channel that sends water from the bathtub to the bathtub via the pump, the pressurized tank, and the microbubble generating unit, A second flow path is defined for sending water from the aforementioned water supply channel to the bathtub via the pressurized tank, The aforementioned microbubble generation system is By driving the pump with the first flow path defined in the microbubble generation circuit, a microbubble generation operation is performed in which water containing microbubbles is supplied to the bathtub, A microbubble generation system configured to perform a tank cleaning operation, which involves defining the second flow path in the microbubble generation circuit and flowing water from the water supply channel into the pressurized tank to clean the pressurized tank.

2. The microbubble generation system further comprises a cistern including a water reservoir provided in the water supply channel and storing water supplied from the water source in an open state to the atmosphere, and an overflow channel for discharging water that overflows from the water reservoir. The microbubble generation system according to claim 1, wherein the second flow path is a flow path that sends water from the water supply channel to the bathtub via the pump and the pressurized tank.

3. The gas introduction mechanism is switchable between an ON state in which gas is introduced into the microbubble generation circuit and an OFF state in which gas is not introduced into the microbubble generation circuit. The microbubble generation system is provided in the pressurized tank and further includes a water level electrode for detecting the water level in the pressurized tank. The microbubble generation system according to claim 1, wherein the microbubble generation system is configured to switch the gas introduction mechanism between the ON state and the OFF state according to the water level in the pressurized tank detected by the water level electrode.

4. The aforementioned microbubble generation circuit is First switching valve and The second switching valve, A first bathtub passage, one end of which is connected to the first switching valve and the other end of which is connected to the bathtub, A second bathtub passage, one end of which is connected to the second switching valve and the other end of which is connected to the bathtub, A tank forward path, one end of which is connected to the first switching valve and the other end of which is connected to the outlet of the pressurized tank, A tank return line, one end of which is connected to the second switching valve and the other end of which is connected to the inlet of the pressurized tank, A communication passage having one end connected to the first switching valve and the other end connected to the second switching valve, The system includes a transfer path, one end of which is connected to the middle of the aforementioned connecting passage and the other end of which is connected to the middle of the tank return path. The first switching valve is configured to switch the flow state of water between one end of the first bathtub passage, one end of the tank supply passage, and one end of the connecting passage. The second switching valve is configured to switch the flow state of water between one end of the second bathtub passage, one end of the tank return passage, and the other end of the connecting passage. The pump is provided in the transport path, The microbubble generating unit is provided in the first bathtub passage, The downstream end of the water supply channel is connected to the middle of the transfer channel. The microbubble generation system according to claim 2, further comprising a third switching valve that switches between a state that allows water supply from the water supply channel to the return channel and a state that prohibits water supply.

5. The third switching valve is installed at the water supply point to which the downstream end of the water supply channel is connected within the supply channel, and divides the supply channel into a first supply channel upstream of the water supply point and a second supply channel downstream of the water supply point. The third switching valve is configured to switch the flow state of water between the downstream end of the first supply line, the upstream end of the second supply line, and the downstream end of the water supply line. The pump is provided in the second supply path, When the microbubble generation system defines the first flow path in the microbubble generation circuit, the third switching valve is configured to allow water flow at the downstream end of the first supply path, allow water flow at the upstream end of the second supply path, and prohibit water flow at the downstream end of the water supply path. The microbubble generation system according to claim 4, wherein, when the microbubble generation circuit defines the second flow path, the third switching valve is configured to prohibit the flow of water at the downstream end of the first supply path, allow the flow of water at the upstream end of the second supply path, and allow the flow of water at the downstream end of the water supply path.

6. The third switching valve is installed at the water supply point to which the downstream end of the water supply channel is connected within the supply channel, and divides the supply channel into a first supply channel upstream of the water supply point and a second supply channel downstream of the water supply point. The third switching valve is configured to switch the flow state of water between the downstream end of the first supply line, the upstream end of the second supply line, and the downstream end of the water supply line. The pump is provided in the second supply path, The microbubble generation system allows the second switching valve to allow water to flow at one end of the second bathtub passage, to allow water to flow at one end of the tank return passage, and to allow water to flow at the other end of the connecting passage, and allows the third switching valve to allow water to flow at the downstream end of the first return passage, to allow water to flow at the upstream end of the second return passage, and to allow water to flow at the downstream end of the water supply passage, thereby causing water from the water supply passage to flow into the second switching valve via the third switching valve and the second return passage, sending a portion of the water flowing into the second switching valve to the bathtub via the second bathtub passage, and allowing the remaining portion of the water flowing into the second switching valve to flow back into the second switching valve via the connecting passage, the first return passage, the third switching valve, and the second return passage. The microbubble generation system according to claim 4, further configured to perform a return path cleaning operation for cleaning the return path by driving the pump with the third flow path defined in the microbubble generation circuit.

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