JP2023012783A - Fine bubble generation device - Google Patents

Abstract

To provide a technology capable of stably and continuously generating fine bubbles in liquid of a liquid tank.SOLUTION: A control device of a fine bubble generation device can execute fine bubble generation operation for driving a booster pump, pressurizing and supplying liquid from a tank supply passage to a tank, and supplying the liquid with gas dissolved under pressure from the tank to a liquid tank through a tank exhaust passage. The control device can execute tank circulation operation for circulating the liquid in the tank with a tank circulation passage by a tank circulation pump during the execution of the fine bubble generation operation, and generating negative pressure in a decompression part of a gas introduction mechanism. The control device is configured so as to open a second gas introduction valve first, and then, open a first gas introduction valve in the case of opening both the first gas introduction valve and the second gas introduction valve from a closed state when the fine bubble generation operation is executed and the tank circulation operation is executed.SELECTED DRAWING: Figure 5

Description

The technology disclosed in this specification relates to a microbubble generator.

Patent Document 1 discloses a tank for pressurizing and dissolving a gas into a liquid, a tank supply path for supplying the liquid to the tank, a pressurizing pump provided in the tank supply path, and the gas from the tank to the liquid tank. a tank discharge path for discharging the liquid in which the gas is pressurized and dissolved; and a microbubble generating nozzle provided in the tank discharge path for decompressing the liquid in which the gas is pressurized and dissolved to generate microbubbles. , a micro-bubble generator provided with a gas introduction mechanism provided in the tank and a controller. The gas introduction mechanism includes a gas introduction port that introduces the gas, a gas introduction path that communicates between the tank and the gas introduction port, and a gas introduction mechanism that opens and closes the gas introduction path. Equipped with a valve. The control device supplies the liquid from the tank to the liquid tank while the gas introduction valve is open, thereby performing a gas introduction operation for introducing the gas into the tank, and closing the gas introduction valve. In this state, the pressurizing pump is driven to pressurize and supply the liquid from the tank supply path to the tank, and the gas is pressurized and dissolved from the tank to the liquid tank through the tank discharge path. The microbubble generation operation for supplying the liquid is alternately performed.

Japanese Patent Application Laid-Open No. 2009-18118

In the microbubble generator of Patent Document 1, the gas introduction operation and the microbubble generation operation cannot be performed at the same time, and the gas is supplied to the tank in the gas introduction operation, and the gas is consumed from the tank in the microbubble generation operation. Therefore, the gas introduction operation and the fine bubble generation operation must be performed alternately. However, during execution of the gas introduction operation, it is not possible to generate microbubbles in the liquid supplied from the tank to the liquid tank. It has been difficult to stably and continuously generate microbubbles in the liquid in the liquid tank. The present specification provides a technique capable of stably and continuously generating microbubbles in a liquid in a liquid tank.

The microbubble generator disclosed in the present specification includes a tank for pressurizing and dissolving gas in a liquid, a tank supply path for supplying the liquid to the tank, a pressure pump provided in the tank supply path, and the a tank discharge path for discharging the liquid in which the gas is pressurized and dissolved from the tank to the liquid tank; A fine bubble generating nozzle to be generated and the tank discharge path are provided separately, and a tank circulation path for sending the liquid from an outlet connected to the tank to an inlet connected to the tank, and the tank A tank circulation pump provided in the circulation path, a gas introduction mechanism provided in the tank circulation path, and a control device are provided. The gas introduction mechanism includes a decompression section that decompresses the liquid to pass through, a gas introduction port that introduces the gas by the negative pressure of the liquid in the decompression section, and a gas that communicates the decompression section and the gas introduction port. an introduction path, a first gas introduction valve provided in the gas introduction path for opening and closing the gas introduction path, and a first gas introduction valve provided in the gas introduction path between the first gas introduction valve and the gas introduction port. and includes a second gas introduction valve for opening and closing the gas introduction path. The first gas introduction valve is configured to receive a force in the direction of opening the first gas introduction valve when negative pressure of the liquid in the decompression section acts. The second gas introduction valve is configured to receive a force in the direction of closing the second gas introduction valve when the negative pressure of the liquid in the decompression section acts. The control device drives the pressure pump to pressurize and supply the liquid from the tank supply passage to the tank, and pressurize the gas from the tank to the liquid tank through the tank discharge passage. A microbubble generation operation can be performed that supplies the dissolved liquid. The control device causes the tank circulation pump to circulate the liquid in the tank through the tank circulation path during execution of the fine bubble generation operation, thereby generating a negative pressure in the decompression unit of the gas introduction mechanism. Circulating operation can be performed. When opening both the first gas introduction valve and the second gas introduction valve from a closed state, the control device first opens the second gas introduction valve, and then opens the first gas introduction valve. It is configured to open the introduction valve.

In the fine bubble generator described above, even during the fine bubble generation operation, the tank circulation operation is performed with the first gas introduction valve and the second gas introduction valve opened, so that the gas introduction mechanism can be introduced to supply gas to the tank. Therefore, it is not necessary to interrupt the microbubble generation operation in order to supply the gas to the tank, and the microbubble generation operation can be continued. With such a configuration, it is possible to stably and continuously generate fine bubbles in the liquid in the liquid tank.

Further, in the fine bubble generator described above, the gas introduction path is provided with the first gas introduction valve and the second gas introduction valve, and the second gas introduction valve is provided between the first gas introduction valve and the gas introduction port. When the negative pressure of the liquid in the decompression section acts on the first gas introduction valve, a force in the direction of opening the first gas introduction valve acts on the first gas introduction valve, and the second gas introduction valve acts on the second gas introduction valve. When the negative pressure acts, a force acts to close the second gas introduction valve. For this reason, for example, when both the first gas introduction valve and the second gas introduction valve are to be opened from the closed state when the fine bubble generation operation and the tank circulation operation are being performed at the same time, the first gas introduction valve must be opened first. If the gas introduction valve is opened, the negative pressure of the liquid in the decompression section will act on the second gas introduction valve when the second gas introduction valve is subsequently opened, and the second gas introduction valve may not operate smoothly. be. As in the above configuration, when both the first gas introduction valve and the second gas introduction valve are opened from the closed state, by opening the second gas introduction valve first, the liquid in the decompression section is Negative pressure can be suppressed from acting on the second gas introduction valve, and the second gas introduction valve can be operated smoothly.

In the microbubble generating device, the control device first reduces the flow rate of the pressurizing pump to the first when opening the first gas introduction valve from the closed state during execution of the microbubble generating operation. It may be configured such that the first flow rate is reduced to a second flow rate that is smaller than the first flow rate, and then the first gas introduction valve is opened.

When the fine bubble generating operation is executed, if the flow rate of the pressurizing pump is large, the pressure in the tank increases, and the pressure of the liquid in the decompression section of the gas introduction mechanism also increases. That is, the negative pressure of the liquid in the decompression section becomes smaller. Conversely, when the flow rate of the pressurizing pump is small, the pressure in the tank becomes low, and the pressure of the liquid in the decompression section of the gas introduction mechanism also becomes low. That is, the negative pressure of the liquid in the decompression section increases. Since the force in the direction of opening the first gas introduction valve acts on the first gas introduction valve due to the negative pressure of the liquid in the decompression section, the pressure of the liquid in the decompression section is low when the first gas introduction valve is opened. The more smoothly the first gas introduction valve can be operated. According to the above configuration, when the first gas introduction valve is opened from the closed state, the flow rate of the pressurizing pump is first reduced from the first flow rate to the second flow rate. Since the pressure of the liquid in the decompression section is lowered and then the first gas introduction valve is opened, the first gas introduction valve can be operated smoothly. Note that the first flow rate and the second flow rate can be set to arbitrary flow rates, respectively. For example, the first flow rate may be the flow rate of the pressurizing pump when performing the fine bubble generation operation with the first gas introduction valve closed, and the second flow rate may be the flow rate with the first gas introduction valve open. It may be the flow rate of the pressurizing pump when performing both the microbubble generation operation and the tank circulation operation in the state where the pressure is maintained. Alternatively, the first flow rate may be the flow rate of the pressure pump when the liquid level in the tank is rising during the microbubble generation operation, and the second flow rate is the microbubble generation operation and the tank It may be the flow rate of the pressurizing pump when the liquid level in the tank is falling during both circulation operations.

In the microbubble generator, the control device first reduces the flow rate of the tank circulation pump to a third The flow rate may be increased to a fourth flow rate that is greater than the third flow rate, and then the first gas introduction valve may be opened.

When the tank circulation operation is executed, if the flow rate of the tank circulation pump is small, the pressure of the liquid in the decompression section of the gas introduction mechanism becomes high. That is, the negative pressure of the liquid in the decompression section becomes smaller. Conversely, when the flow rate of the tank circulation pump is large, the pressure of the liquid in the decompression section of the gas introduction mechanism becomes low. That is, the negative pressure of the liquid in the decompression section increases. Since the force in the direction of opening the first gas introduction valve acts on the first gas introduction valve due to the negative pressure of the liquid in the decompression section, the pressure of the liquid in the decompression section is low when the first gas introduction valve is opened. The more smoothly the first gas introduction valve can be operated. According to the above configuration, when the first gas introduction valve is opened from the closed state, by first increasing the flow rate of the tank circulation pump from the third flow rate to the fourth flow rate, the gas introduction mechanism Since the pressure of the liquid in the decompression section is lowered and then the first gas introduction valve is opened, the first gas introduction valve can be operated smoothly. Note that the third flow rate and the fourth flow rate can be set to arbitrary flow rates, respectively. For example, the third flow rate is the flow rate of the tank circulation pump when the fine bubble generation operation is performed with the first gas introduction valve closed (when the tank circulation operation is performed with the first gas introduction valve closed is the flow rate of the tank circulation pump at that time, which is zero when the tank circulation operation is not performed with the first gas introduction valve closed), and the fourth flow rate is the flow rate of the It may be the flow rate of the tank circulation pump when performing both the fine bubble generation operation and the tank circulation operation with the gas introduction valve open. Alternatively, the third flow rate may be the flow rate of the tank circulation pump when the liquid level in the tank rises during the fine bubble generation operation, and the fourth flow rate is the fine bubble generation operation and the tank It may be the flow rate of the tank circulation pump when the liquid level in the tank is falling during both circulation operations.

In the microbubble generator, the controller closes the first gas introduction valve first when closing both the first gas introduction valve and the second gas introduction valve from an open state. , and then the second gas introduction valve may be closed.

In the fine bubble generator described above, the gas introduction path is provided with the first gas introduction valve and the second gas introduction valve, and the second gas introduction valve is provided between the first gas introduction valve and the gas introduction port. When the negative pressure of the liquid in the decompression section acts on the first gas introduction valve, a force in the direction of opening the first gas introduction valve acts on the first gas introduction valve, and the negative pressure of the liquid in the decompression section acts on the second gas introduction valve. acts, a force acts in the direction of closing the second gas introduction valve. For this reason, for example, when both the first gas introduction valve and the second gas introduction valve are closed while the fine bubble generation operation and the tank circulation operation are being performed at the same time, the second gas introduction valve must be closed first. If the gas introduction valve is closed, when the second gas introduction valve is closed, the negative pressure of the liquid in the decompression part acts on the second gas introduction valve, and the valve body of the second gas introduction valve strongly collides with the valve seat. This may lead to noise generation and damage to the second gas introduction valve. As in the above configuration, when both the first gas introduction valve and the second gas introduction valve are closed from the open state, the first gas introduction valve is closed first, and then the second gas introduction valve is closed. When the introduction valve is closed, the negative pressure of the liquid in the decompression part can be suppressed from acting on the second gas introduction valve, and the valve body of the second gas introduction valve strongly collides with the valve seat. , the generation of noise and damage to the second gas introduction valve can be suppressed.

In the microbubble generator, the liquid may be water, and the liquid bath may be a bathtub used by a user for bathing.

According to the above configuration, fine air bubbles can be stably and continuously generated in the water of the bathtub used by the user for bathing.

It is a figure which shows typically the structure of the water heater 2 of an Example. Fig. 4 is a cross-sectional view showing a state in which both the first gas introduction valve 106 and the second gas introduction valve 108 are closed in the gas introduction mechanism 96 of the water heater 2 of the embodiment; Fig. 4 is a cross-sectional view showing a state in which both the first gas introduction valve 106 and the second gas introduction valve 108 are open in the gas introduction mechanism 96 of the water heater 2 of the embodiment; Fig. 4 is a cross-sectional view showing a state in which the first gas introduction valve 106 is open and the second gas introduction valve 108 is closed, in the gas introduction mechanism 96 of the water heater 2 of the embodiment; Fig. 4 is a cross-sectional view showing a state in which the first gas introduction valve 106 is closed and the second gas introduction valve 108 is open in the gas introduction mechanism 96 of the water heater 2 of the embodiment; It is a figure which shows typically the cross section of the bathtub adapter 132 of the water heater 2 of an Example. 4 is a flow chart of processing executed by the controller 150 in the hot water filling operation of the water heater 2 of the embodiment. It is a figure which shows typically the example of the flow of the water in the water heater 2 of an Example. FIG. 4 is a diagram schematically showing another example of water flow in the water heater 2 of the embodiment; 4 is a flow chart of processing executed by the control device 150 in microbubble generation operation of the water heater 2 of the embodiment. 4 is a flow chart of air introduction amount adjustment processing executed by the control device 150 in the microbubble generation operation of the water heater 2 of the embodiment. FIG. 5 is a diagram schematically showing still another example of water flow in the water heater 2 of the embodiment; FIG. 5 is a diagram schematically showing still another example of water flow in the water heater 2 of the embodiment; 9 is a flowchart of air introduction amount adjustment processing executed by the control device 150 in the microbubble generating operation of the water heater 2 of the modified example. It is a figure which shows typically the structure of the water heater 2 of another modification.

(Example)
As shown in FIG. 1, the water heater 2 of this embodiment includes a heat source unit 10, an air pressure dissolving unit 50, a bathtub adapter 132, and a control device 150. As shown in FIG. The water heater 2 heats water supplied from a water supply source 200 such as tap water, and supplies the water heated to a desired temperature to the faucet 250 installed in the kitchen or the like and the bathtub 130 installed in the bathroom. can do. Moreover, the water heater 2 can generate fine air bubbles in the water of the bathtub 130 used by the user for bathing.

(Configuration of heat source unit 10)
The heat source unit 10 includes a first heat source device 12, a second heat source device 14, a water supply path 16, a hot water outlet path 18, a bypass path 20, a bypass servo 22, a hot water pouring path 24, and a hot water filling valve 26. , a water quantity sensor 28 , an outward circulation path 30 , a return circulation path 32 , a bathtub circulation pump 34 , and a water flow switch 36 .

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 . The upstream end of the hot water outlet 18 is connected to the first heat source machine 12 , and the downstream end of the hot water outlet 18 is connected to the callan 250 . The first heat source device 12 is, for example, a combustion heat source device that heats water by combustion of gas. The first heat source machine 12 heats the water flowing from the water supply channel 16 and sends the heated water to the hot water outlet channel 18 .

The upstream end of the bypass 20 is connected to the water supply channel 16 and the downstream end of the bypass 20 is connected to the hot water outlet 18 . A bypass servo 22 is provided at a location where the bypass passage 20 connects to the water supply passage 16 . By adjusting the degree of opening of the built-in valve body, the bypass servo 22 controls the flow rate of water flowing from the water supply path 16 to the hot water supply path 18 via the first heat source machine 12 and the bypass path 20 from the water supply path 16. It is possible to adjust the flow rate of the water flowing through to the hot water outlet 18 . By adjusting the degree of opening of the bypass servo 22, high-temperature water flowing from the first heat source machine 12 and low-temperature water flowing from the bypass 20 flow into the hot water outlet passage 18 on the downstream side of the location where the bypass 20 is connected. are mixed in a desired ratio, and water adjusted to a desired temperature is supplied. A hot water outlet temperature thermistor 18a for detecting the temperature of the water in the hot water outlet path 18 is provided in the hot water outlet 18 downstream of the location where the bypass 20 is connected.

The upstream end of the hot water pouring channel 24 is connected to the hot water outlet channel 18 on the downstream side of the location where the bypass 20 is connected, and the downstream end of the hot water pouring channel 24 is connected to the circulation return channel 32 . The hot water filling valve 26 is provided in the pouring path 24 and opens and closes the pouring path 24 . The hot water filling valve 26 is normally closed. A water quantity sensor 28 is provided in the pouring path 24 and detects the quantity of water flowing through the pouring path 24 .

The upstream end of the circulation return path 32 is connected to the heat source return path 60 (details will be described later) of the air pressure melting unit 50 , and the downstream end of the circulation return path 32 is connected to the second heat source machine 14 . The upstream end of the outward circulation path 30 is connected to the second heat source device 14, and the downstream end of the outward circulation path 30 is connected to the outward heat source path 68 (details will be described later) of the pressurized air melting unit 50. . The second heat source device 14 is, for example, a combustion heat source device that heats water by combustion of gas. The second heat source machine 14 heats the water flowing from the return circulation path 32 and sends the heated water to the outward circulation path 30 . A return circulation path thermistor 32 a for detecting the temperature of the water in the return circulation path 32 is provided near the upstream end of the return circulation path 32 . An outward circulation path thermistor 30 a that detects the temperature of the water in the outward circulation path 30 is provided near the downstream end of the outward circulation path 30 .

The bathtub circulation pump 34 is provided in the return circulation path 32 on the downstream side of the connection point of the hot water supply path 24 , and sends out the water in the return circulation path 32 toward the second heat source machine 14 . The water flow switch 36 is provided between the bathtub circulation pump 34 and the second heat source machine 14 in the return circulation path 32 and detects whether or not water is flowing through the return circulation path 32 .

(Configuration of air pressurized dissolving unit 50)
The air pressurized dissolving unit 50 includes a tank 52, a heat source return path 60, a heat source outward path 68, a tank return path 74, a tank connection path 76, a tank outward 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 pressure pump 88, a second pressure pump 90, a tank suction passage 92, a tank circulation pump 94, and a gas introduction mechanism. It has 96.

The tank 52 can store water inside. Inside the tank 52, a low water level electrode 52a, a high water level electrode 52b and a ground electrode 52c for detecting the water level in the tank 52 are installed. The water level detected by the low water level electrode 52a (hereinafter also referred to as the lower water level) is lower than the water level detected by the high water level electrode 52b (hereinafter also referred to as the upper water level). When the low water level electrode 52 a and the high water level electrode 52 b contact the surface of the water stored in the tank 52 , current flows between them and the ground electrode 52 c to output an ON signal to the controller 150 . The tank 52 is used to pressurize and dissolve air in water to produce air-dissolved water.

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 . A communication passage 66 , a first bathtub water passage 62 , and a tank forward passage 64 are connected to the first three-way valve 80 . The first three-way valve 80 is in a first communication state (see FIGS. 12 and 13) in which the tank outward passage 64 and the first bathtub water passage 62 are in communication, and a second communication state in which the tank outward passage 64 and the communication passage 66 are in communication. A state (see FIG. 1) and a third communication state (see FIGS. 8 and 9) in which the first bathtub water channel 62, the tank outward channel 64, and the communication channel 66 are in communication can be switched. The upstream end of the tank outward passage 64 is connected to the lower portion of the tank 52 , and the downstream end of the tank outward passage 64 is connected to the first three-way valve 80 . The forward tank passage 64 is provided with 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. ing. One end of the first bathtub water channel 62 is connected to the first three-way valve 80 and the other end of the first bathtub water channel 62 is connected to the bathtub adapter 132 .

One end of the heat source outward path 68 is connected to the circulation outward path 30 of the heat source unit 10 , and the other end of the heat source outward path 68 is connected to the second three-way valve 82 . The second three-way valve 82 is connected with the communication passage 66 , the heat source outward passage 68 , and the second bathtub water passage 70 . The second three-way valve 82 is in a fourth communication state (see FIGS. 12 and 13) in which the second bathtub water passage 70 and the communication passage 66 communicate, and in a fifth communication state (see FIGS. 12 and 13) in which the heat source outward passage 68 and the second bathtub water passage 70 communicate. 1, 8, and 9) can be switched. One end of the second bathtub water channel 70 is connected to the second three-way valve 82 , and the other end of the second bathtub water channel 70 is connected to the bathtub adapter 132 .

The upstream end of the tank return path 74 is connected to the heat source outward path 68 , and the downstream end of the tank return path 74 is connected to the upstream end of the tank connection path 76 . A downstream end of the tank connection path 76 (hereinafter also referred to as an inflow port 76 a ) is connected to the top of the tank 52 . The water level at the point where the inlet 76a of the tank connection path 76 is connected to the tank 52 is higher than the upper limit water level detected by the high water level electrode 52b. 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 closed. The first pressurizing pump 88 and the second pressurizing pump 90 are provided downstream of the tank water supply valve 86 in the tank return path 74 . The first pressurization pump 88 and the second pressurization pump 90 pressurize the water in the tank return path 74 and send it out toward the tank connection path 76 . In the tank return path 74 , the first pressure pump 88 is arranged upstream of the second pressure pump 90 . The water sent from the tank return path 74 to the tank connection path 76 flows into the tank 52 through the inflow port 76a.

An upstream end of the tank suction path 92 (hereinafter also referred to as an outflow port 92 a ) is connected to the bottom of the tank 52 . The water level at the point where the outlet 92a of the tank suction passage 92 is connected to the tank 52 is lower than the lower limit water level detected by the low water level electrode 52a. A downstream end of the tank suction passage 92 is connected to an upstream end of the tank connection passage 76 . A tank circulation pump 94 is provided in the tank suction path 92 . The tank circulation pump 94 sucks the water in the tank 52 into the tank suction passage 92 through the outflow port 92 a and sends the water in the tank suction passage 92 toward the tank connection passage 76 . The water sent from the tank suction passage 92 to the tank connection passage 76 flows into the tank 52 through the inflow port 76a.

The gas introduction mechanism 96 is provided in the tank suction passage 92 on the upstream side 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 , a first gas introduction valve 106 and a second gas introduction valve 108 . Water flows into the water inlet pipe 98 from the upstream side of the tank suction passage 92 . The water discharge pipe 100 causes water to flow out to the downstream side of the tank suction passage 92 . A venturi tube 102 communicates the water inlet pipe 98 and the water outlet pipe 100 . The diameter of venturi tube 102 is smaller than the diameters of inlet pipe 98 and outlet pipe 100 . The water flowing through the gas introduction mechanism 96 is decompressed to a pressure lower than atmospheric pressure when flowing from the water inlet pipe 98 to the venturi pipe 102 , and is increased to the original pressure when flowing from the venturi pipe 102 to the water outlet pipe 100 . The upstream end of gas introduction path 104 (hereinafter also referred to as gas introduction port 110 ) is open to the atmosphere, and the downstream end is connected to venturi tube 102 . A first gas introduction valve 106 and a second gas introduction valve 108 are provided in the gas introduction path 104 and open and close the gas introduction path 104 respectively. In the gas introduction path 104, the first gas introduction valve 106 is arranged downstream of the second gas introduction valve 108 (closer to the venturi tube 102). If both the first gas introduction valve 106 and the second gas introduction valve 108 are open when water flows through the gas introduction mechanism 96, air is sucked into the gas introduction passage 104 from the gas introduction port 110, and the venturi Air is mixed with the water flowing through tube 102 . Air introduced by the gas introduction mechanism 96 is mixed with water flowing through the tank suction passage 92 and flows into the tank 52 via the tank connection passage 76 .

Even if the gas introduction mechanism 96 as described above is provided in the tank return path 74 , air can be introduced by the gas introduction mechanism 96 when water is supplied from the tank return path 74 to the tank 52 . However, with such a configuration, the pressure loss in the tank return path 74 increases, and the pressure of the water sent to the tank 52 by the first pressure pump 88 and the second pressure pump 90 decreases. Moreover, in such a configuration, if the amount of air introduced by the gas introduction mechanism 96 is increased, the pressure of the water sent to the tank 52 is reduced, and the pressure of the water sent to the tank 52 is increased. As a result, the amount of air introduced by the gas introduction mechanism 96 is reduced. On the other hand, in this embodiment, since the gas introduction mechanism 96 is provided in the tank suction path 92 provided separately from the tank return path 74, the pressure loss in the tank return path 74 can be reduced. Also, a large amount of air can be introduced by the gas introduction mechanism 96 while sending water at high pressure from the tank return path 74 to the tank 52 .

(Configuration of gas introduction mechanism 96)
As shown in FIG. 2, the first gas introduction valve 106 and the second gas introduction valve 108 are arranged to face each other. In the following description, the portion of the gas introduction path 104 between the venturi tube 102 and the first gas introduction valve 106 is also referred to as a first gas introduction path 104a. The portion between 108 is also referred to as a second gas introduction path 104b, and the portion between the second gas introduction valve 108 and the gas introduction port 110 is also referred to as a third gas introduction path 104c.

The first gas introduction valve 106 includes a valve chamber 106a, a valve seat 106b, a valve body 106c, a plunger 106d, a coil 106e, and a spring 106f. The valve chamber 106a communicates with the first gas introduction path 104a and communicates with the second gas introduction path 104b via the valve seat 106b. The valve body 106c can be seated on the valve seat 106b, and when the valve body 106c is seated on the valve seat 106b, communication between the valve chamber 106a and the second gas introduction passage 104b is blocked. The valve body 106c is held at the tip of the plunger 106d. Plunger 106d incorporates a core (not shown) made of a magnetic material. Coil 106e exerts a magnetic attraction force on the core of plunger 106d when energized. That is, when the coil 106e is energized, the magnetic attraction force acts on the plunger 106d in the direction in which the valve element 106c separates from the valve seat 106b. The spring 106f applies an urging force to the plunger 106d in the direction in which the valve body 106c is seated on the valve seat 106b. As shown in FIG. 2, when the coil 106e is not energized, the spring 106f exerts a biasing force on the plunger 106d, causing the valve body 106c to be seated on the valve seat 106b and the first gas introduction valve 106 to close. be done. As shown in FIG. 3, when the coil 106e is energized, the magnetic attraction force acting on the plunger 106d from the coil 106e exceeds the biasing force acting on the plunger 106d from the spring 106f. , and the first gas introduction valve 106 is opened. In the first gas introduction valve 106, when the pressure in the first gas introduction passage 104a is lower than the pressure in the second gas introduction passage 104b, the pressure difference causes the valve element 106c to move away from the valve seat 106b. acts on plunger 106d.

The second gas introduction valve 108 includes a valve chamber 108a, a valve seat 108b, a valve body 108c, a plunger 108d, a coil 108e, and a spring 108f. The valve chamber 108a communicates with the third gas introduction path 104c and communicates with the second gas introduction path 104b via the valve seat 108b. The valve body 108c can be seated on the valve seat 108b, and when the valve body 108c is seated on the valve seat 108b, communication between the valve chamber 108a and the second gas introduction passage 104b is blocked. The valve body 108c is held at the tip of the plunger 108d. The plunger 108d incorporates a core (not shown) made of magnetic material. Coil 108e exerts a magnetic attraction force on the core of plunger 108d when energized. That is, when the coil 108e is energized, the magnetic attraction force acts on the plunger 108d in the direction in which the valve element 108c separates from the valve seat 108b. The spring 108f applies an urging force to the plunger 108d in the direction in which the valve body 108c is seated on the valve seat 108b. As shown in FIG. 2, when the coil 108e is not energized, the spring 108f exerts an urging force on the plunger 108d, so that the valve body 108c is seated on the valve seat 108b and the second gas introduction valve 108 is closed. be done. As shown in FIG. 3, when the coil 108e is energized, the magnetic attraction force acting on the plunger 108d from the coil 108e exceeds the biasing force acting on the plunger 108d from the spring 108f. , and the second gas introduction valve 108 is opened. In the second gas introduction valve 108, when the pressure in the second gas introduction passage 104b is lower than the pressure in the third gas introduction passage 104c, the pressure difference causes the valve element 108c to be seated on the valve seat 108b. acts on plunger 108d.

From a state in which both the first gas introduction valve 106 and the second gas introduction valve 108 are closed (see FIG. 2) to a state in which both the first gas introduction valve 106 and the second gas introduction valve 108 are open (see FIG. 3) A case of switching to . As shown in FIG. 4, when the first gas introduction valve 106 is opened first, the first gas introduction passage 104a and the second gas introduction passage 104b communicate with each other while the second gas introduction valve 108 is closed. In this state, when the pressure of the water flowing through the venturi tube 102 is low (that is, the negative pressure of the water in the venturi tube 102 is large), the pressure of the second gas introduction passage 104b is lower than the pressure of the third gas introduction passage 104c. , and the differential pressure acts in the direction of closing the second gas introduction valve 108 . Therefore, it becomes difficult to open the second gas introduction valve 108 smoothly. On the other hand, as shown in FIG. 5, when the second gas introduction valve 108 is opened first, the second gas introduction passage 104b is blocked from the first gas introduction passage 104a. and the pressure of the third gas introduction passage 104c, the second gas introduction valve 108 can be opened smoothly. Moreover, in the state shown in FIG. 5, the second gas introduction path 104b communicates with the third gas introduction path 104c. In this state, when the pressure of the water flowing through the venturi tube 102 is low (that is, the negative pressure of the water in the venturi tube 102 is large), the pressure of the first gas introduction passage 104a becomes lower than the pressure of the second gas introduction passage 104b. , and the differential pressure acts in the direction of opening the first gas introduction valve 106 . Therefore, the first gas introduction valve 106 can be opened smoothly.

From the state in which both the first gas introduction valve 106 and the second gas introduction valve 108 are open (see FIG. 3), to the state in which both the first gas introduction valve 106 and the second gas introduction valve 108 are closed (see FIG. 2) A case of switching to . As shown in FIG. 4, when the second gas introduction valve 108 is closed first, the first gas introduction valve 106 is open, so the first gas introduction path 104a and the second gas introduction path 104b are in communication. In this state, when the pressure of the water flowing through the venturi tube 102 is low (that is, the negative pressure of the water in the venturi tube 102 is large), the pressure of the second gas introduction passage 104b is lower than the pressure of the third gas introduction passage 104c. , and the differential pressure acts in the direction of closing the second gas introduction valve 108 . Therefore, when the second gas introduction valve 108 is closed, the valve body 108c may violently collide with the valve seat 108b, resulting in noise generation and damage to parts. On the other hand, as shown in FIG. 5, if the first gas introduction valve 106 is closed first, the second gas introduction path 104b is cut off from the first gas introduction path 104a. A large differential pressure does not occur between the pressure and the pressure of the third gas introduction passage 104c. Therefore, when the second gas introduction valve 108 is closed, it is possible to prevent the valve body 108c from vigorously colliding with the valve seat 108b, thereby suppressing noise generation and component damage.

(Configuration of bathtub adapter 132)
Next, the bathtub adapter 132 provided on the wall portion 130a of the bathtub 130 will be described with reference to FIGS. 6(a) and 6(b). FIG. 6A shows a state in which water flows from the first bathtub water channel 62 toward the bathtub 130 and water flows from the bathtub 130 toward the second bathtub water channel 70 (for example, the state of FIG. 12). Water flow in adapter 132 is shown. FIG. 6(b) shows a state in which water flows from the bathtub 130 toward the first bathtub water channel 62 and water flows from the second bathtub water channel 70 toward the bathtub 130 (for example, the state of FIG. 9). Water flow in adapter 132 is shown.

Bathtub adapter 132 includes a first water channel 136 and a second water channel 138 . The first water channel 136 communicates with the first bathtub water channel 62 , and the second water channel 138 communicates with the second bathtub water channel 70 . The first water channel 136 branches into a first discharge channel 136a and a first suction channel 136b. The first discharge passage 136 a communicates with a first discharge port 134 a provided on the front surface 132 a of the bathtub adapter 132 . Water discharged from the first outlet 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. As shown in FIG. In the first discharge passage 136a, a non-return portion 140a for preventing the flow of water from the bathtub 130 toward the first bathtub water passage 62, and a non-return portion 140a disposed on the upstream side (first bathtub water passage 62 side) of the non-return portion 140a. A fine bubble generating nozzle 142 is provided. The fine bubble generation nozzle 142 decompresses the water passing through the fine bubble generation nozzle 142 . The first suction path 136b communicates with a first suction port 134b provided on the front surface 132a of the bathtub adapter 132. As shown in FIG. The first suction passage 136b is provided with a non-return portion 140b that prevents water from flowing from the first bathtub water passage 62 toward the bathtub 130. As shown in FIG.

The second water channel 138 branches into a second discharge channel 138a and a second suction channel 138b. The second suction path 138b communicates with a second suction port 134c provided on the front surface 132a of the bathtub adapter 132 . The second suction passage 138b is provided with a non-return portion 140c that prevents water from flowing from the second bathtub water passage 70 toward the bathtub 130. As shown in FIG. The second discharge passage 138 a communicates with a second discharge port 134 d provided on the lower surface 132 b 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. As shown in FIG. A non-return portion 140d that prevents water from flowing from the bathtub 130 toward the second bathtub water passage 70 is provided in the second discharge passage 138a.

(Configuration of control device 150)
A control device 150 shown in FIG. 1 controls the operation of each component of the heat source unit 10 and the pressurized air melting unit 50 . Control device 150 is configured to communicate with a user-operable remote control 154 . The control device 150 includes a memory 152, and can store various settings such as the set temperature and the set amount of water for the hot water refilling operation and the set temperature for the reheating operation input by the user. Via the remote controller 154, the user can instruct the start and end of the hot water filling operation, the microbubble generation operation, and the reheating operation, which will be described later.

(Hot water filling operation)
The hot water filling operation is started when the user instructs the start of the hot water filling operation with the remote controller 154 . Alternatively, the hot water filling operation may be started 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 hot water filling operation start time has arrived. When the hot water filling operation is started, the control device 150 puts the first three-way valve 80 and the second three-way valve 82 in the third communication state and the fifth communication state, respectively (see FIGS. 8 and 9). From this state, the control device 150 executes the processing shown in FIG.

In S2, control device 150 executes an air removal process. Specifically, the controller 150 opens the hot water filling valve 26 and starts heating the water by the first heat source machine 12 . As a result, as shown in FIG. 8, the water whose temperature is adjusted to the set temperature flows from the hot water supply path 18 to the circulation return path 32 via the hot water supply path 24 . The water that has flowed into the circulation return path 32 branches into a flow toward the upstream side (that is, the heat source return path 60) and a flow toward the downstream side (that is, the second heat source machine 14). Water flowing from the circulation return path 32 to the heat source return path 60 flows into the bathtub 130 via the communication path 66 , the first three-way valve 80 , the first bathtub water path 62 and the bathtub adapter 132 . Water flowing from the return circulation path 32 to the second heat source machine 14 flows into the bathtub 130 via the outward circulation path 30 , the outward heat source path 68 , the second three-way valve 82 , the second bathtub water passage 70 , and the bathtub adapter 132 . As a result, the insides of the first bathtub water passage 62 and the second bathtub water passage 70 are filled with water, and the air remaining inside the first bathtub water passage 62 and the second bathtub water passage 70 is discharged to the bathtub 130 . When the integrated amount of water detected by the water amount sensor 28 reaches a predetermined value (for example, 6 L), the control device 150 closes the hot water supply valve 26, terminates the heating by the first heat source device 12, and terminates the air removal process. .

In S<b>4 , control device 150 executes remaining water detection processing for bathtub 130 . Specifically, as shown in FIG. 9, the control device 150 drives the bathtub circulation pump 34 to determine whether there is residual water in the bathtub 130 based on whether the water flow switch 36 detects water flow. to judge whether When there is no remaining water in the bathtub 130 and the bathtub adapter 132 is not submerged in water, even if the bathtub circulation pump 34 is driven, the water flow switch 36 does not detect the water flow. In contrast, when the bathtub 130 has residual water and the bathtub adapter 132 is submerged in water, when the bathtub circulation pump 34 is activated, the water flow switch 36 detects the water flow. If there is residual water in bathtub 130 in S4 (in the case of YES), the process proceeds to S6. If there is no residual water in bathtub 130 in S4 (NO), the process proceeds to S10.

In S<b>6 , the control device 150 performs processing for determining the amount of remaining water in the bathtub 130 . Specifically, the controller 150 drives the bathtub circulation pump 34 and stores the temperature detected by the return circulation thermistor 32a as the temperature before heating. After that, the control device 150 starts heating water by the second heat source machine 14 . As a result, as shown in FIG. 9, residual water in the bathtub 130 flows through the bathtub adapter 132, the first bathtub water channel 62, the first three-way valve 80, the communication channel 66, the heat source return channel 60, and the circulation return channel 32 to the second It is sent to the heat source machine 14 . The remaining water heated by the second heat source machine 14 is returned to the bathtub 130 via the outward circulation path 30 , the outward heat source path 68 , the second three-way valve 82 , the second bathtub water passage 70 , and the bathtub adapter 132 . When the temperature detected by the return circulation thermistor 32a reaches or exceeds the set temperature, the controller 150 stores the temperature detected by the return circulation thermistor 32a as the post-heating temperature, stops the bathtub circulation pump 34, and stops the second The heating of water by the heat source device 14 is finished. Then, the control device 150 calculates the remaining water amount of the bathtub 130 from the temperature rise width obtained by subtracting the pre-heating temperature from the post-heating temperature and the integrated heating amount in the second heat source device 14 in S6.

In S8, control device 150 subtracts the amount of water remaining in bathtub 130 determined in S6 from the set amount of water for the hot water filling operation to update the set amount of water for the hot water filling operation.

In S<b>10 , the controller 150 opens the hot water filling valve 26 and starts heating by the first heat source machine 12 . As a result, as shown in FIG. 8, the water whose temperature is adjusted to the set temperature flows from the hot water supply path 18 to the circulation return path 32 via the hot water supply path 24 . The water that has flowed into the circulation return path 32 branches into a flow toward the upstream side (that is, the heat source return path 60) and a flow toward the downstream side (that is, the second heat source machine 14). Water flowing from the circulation return path 32 to the heat source return path 60 flows into the bathtub 130 via the communication path 66 , the first three-way valve 80 , the first bathtub water path 62 and the bathtub adapter 132 . Water flowing from the return circulation path 32 to the second heat source machine 14 flows into the bathtub 130 via the outward circulation path 30 , the outward heat source path 68 , the second three-way valve 82 , the second bathtub water passage 70 , and the bathtub adapter 132 .

In S12, the control device 150 waits until the integrated amount of water detected by the water amount sensor 28 reaches the set amount of water for the hot water filling operation. The cumulative amount of water referred to here is the sum of the cumulative amount of water detected by the water amount sensor 28 in the air removal process in S2 and the cumulative amount of water after the start of filling the bathtub 130 in S10. When the cumulative amount of water reaches the set amount of water (if YES), the process proceeds to S14.

In S<b>14 , the control device 150 closes the hot water filling valve 26 and ends the heating of water by the first heat source machine 12 .

In S16, the control device 150 drives the bathtub circulation pump 34 to obtain the temperature detected by the return circulation thermistor 32a as the temperature of the bathtub water. Then, control device 150 determines whether or not the bathtub water temperature is equal to or higher than the set temperature. If the bathtub water temperature is less than the set temperature (NO), the process proceeds to S18. If the bathtub water temperature is equal to or higher than the set temperature (if YES), the process proceeds to S20.

In S<b>18 , the control device 150 performs reheating of the water in the bathtub 130 . Specifically, controller 150 drives bathtub circulation pump 34 and starts water heating by second heat source device 14 . As a result, as shown in FIG. 9, the water in the bathtub 130 flows through the bathtub adapter 132, the first bathtub water channel 62, the first three-way valve 80, the communication channel 66, the heat source return channel 60, and the circulation return channel 32 to the second heat source. sent to machine 14. The water heated by the second heat source machine 14 is returned to the bathtub 130 via the outward circulation path 30 , the outward heat source path 68 , the second three-way valve 82 , the second bathtub water passage 70 , and the bathtub adapter 132 . When the temperature detected by the return circulation thermistor 32a reaches or exceeds the set temperature, the control device 150 stops the bathtub circulation pump 34 and ends the water heating by the second heat source device 14 .

In S20, control device 150 notifies the user via remote control 154 that the hot water filling operation has been completed. After S20, the process of FIG. 7 ends.

(Fine bubble generation operation)
The microbubble generation operation is started when the user instructs the start of the microbubble generation operation with the remote controller 154 . Further, in the water heater 2 of the present embodiment, after the above-described hot water filling operation is completed, the microbubble generating operation is automatically started. That is, the microbubble generation operation is performed in conjunction with the execution of the hot water filling operation. The control device 150 puts the first three-way valve 80 and the second three-way valve 82 in the third communication state and the fifth communication state, respectively, when starting the microbubble generation operation (see FIGS. 8 and 9). From this state, the control device 150 executes the processing shown in FIG.

In S32, control device 150 executes a cold water mitigation process. Specifically, the controller 150 drives the bathtub circulation pump 34 when the temperature detected by the outward circulation thermistor 30a and the return circulation thermistor 32a is equal to or lower than a predetermined temperature, and also causes the second heat source device 14 to heat the water. Start heating. As a result of this cold water mitigation process, when low-temperature water remains inside the outward circulation path 30 and the return circulation path 32, as shown in FIG. It flows into the bathtub adapter 132 via the two-bathtub channel 70 and is discharged from the second outlet 134d of the bottom surface 132b of the bathtub adapter 132 into the bathtub 130 . Therefore, even if the user is taking a bath in the bathtub 130, it is possible to prevent low-temperature water from being discharged directly toward the user's body. When a predetermined time has passed since the start of the cold water relaxation process, the control device 150 stops the bathtub circulation pump 34, ends the water heating by the second heat source machine 14, and ends the cold water relaxation process.

At S<b>34 , the controller 150 opens the second gas introduction valve 108 .

At S<b>36 , the controller 150 drives the tank circulation pump 94 . This initiates water circulation between tank 52 and tank suction passage 92 and tank connection passage 76 . When driving the tank circulation pump 94 in S34, the controller 150 sets the rotation speed of the tank circulation pump 94 to a higher rotation speed than the standard rotation speed (for example, 120% of the standard rotation speed). to control the tank circulation pump 94.

At S<b>38 , the controller 150 opens the first gas introduction valve 106 . As a result, air is introduced into the water flowing through the gas introduction mechanism 96 of the tank suction path 92 .

In S40, the controller 150 controls the tank circulation pump 94 so that the rotation speed of the tank circulation pump 94 becomes the standard rotation speed. This reduces the flow rate of water pumped by the tank circulation pump 94 .

In S<b>42 , control device 150 starts supplying air-dissolved water from tank 52 to bathtub 130 . Specifically, as shown in FIG. 12, the control device 150 sets the first three-way valve 80 to the first communication state and sets the second three-way valve 82 to the fourth communication state, and then controls the bathtub circulation pump 34, The first pressure pump 88 and the second pressure pump 90 are driven. As a result, the water in the bathtub 130 flows through the bathtub adapter 132, the second bathtub water passage 70, the second three-way valve 82, the communication passage 66, the heat source return passage 60, the circulation return passage 32, the second heat source machine 14, the circulation outward passage 30, and the heat source outward passage 68. , a tank return path 74 and a tank connection path 76 to the tank 52 . At this time, water pressurized by the first pressure pump 88 and the second pressure pump 90 is supplied to the tank 52 . As a result, the air is pressurized and dissolved in the water inside the tank 52 . Then, the water in which the air is pressurized and dissolved is supplied from the tank 52 to the bathtub 130 via the tank outward passage 64 , the first three-way valve 80 , the first bathtub water passage 62 and the bathtub adapter 132 . At this time, the water in which the air is pressurized and dissolved is depressurized to below atmospheric pressure when passing through the fine bubble generating nozzle 142 of the first discharge passage 136a of the bathtub adapter 132, and is jetted into the bathtub 130. , the pressure is increased to the atmospheric pressure, and microbubbles are generated in the water in the bathtub 130 .

At S44 shown in FIG. 10, the control device 150 executes the air introduction amount adjustment process shown in FIG.

In S62 shown in FIG. 11, the control device 150 determines whether or not the water level of the tank 52 is below the minimum water level based on the detection signal from the low water level electrode 52a. In this embodiment, in the gas introduction mechanism 96, the amount of air introduced when the first gas introduction valve 106 and the second gas introduction valve 108 are open is larger than the amount of fine air bubbles generated in the water in the bathtub 130. many. Therefore, when the first gas introduction valve 106 and the second gas introduction valve 108 are open, the amount of air in the tank 52 increases and the water level in the tank 52 decreases. If the water level in the tank 52 is below the lower limit water level (if YES), the process proceeds to S64. If the water level in the tank 52 is equal to or higher than the lower limit water level (NO), the process proceeds to S68.

In S<b>64 , the control device 150 closes the first gas introduction valve 106 . This stops the introduction of air into the water flowing through the gas introduction mechanism 96 of the tank suction path 92 . In this embodiment, even while the first gas introduction valve 106 is closed, the tank circulation pump 94 continues to be driven. This promotes water flow within the tank 52 and promotes pressurized dissolution of air into the water in the tank 52 .

At S<b>66 , the control device 150 closes the second gas introduction valve 108 .

In S68, the controller 150 determines whether the water level of the tank 52 is equal to or higher than the upper limit water level based on the detection signal from the high water level electrode 52b. Air is not supplied to the tank 52 when the first gas introduction valve 106 and the second gas introduction valve 108 are closed, so the amount of air in the tank 52 decreases and the water level in the tank 52 rises. If the water level in the tank 52 is equal to or higher than the upper limit water level (if YES), the process proceeds to S70. If the water level in the tank 52 is lower than the upper limit water level (NO), the process of FIG. 11 ends and the process proceeds to S46 (see FIG. 10).

At S<b>70 , the controller 150 opens the second gas introduction valve 108 .

At S<b>72 , the control device 150 stops the second pressurizing pump 90 . As a result, the flow rate of water delivered by the first pressurizing pump 88 and the second pressurizing pump 90 is reduced.

In S74, the controller 150 controls the tank circulation pump 94 so that the rotation speed of the tank circulation pump 94 is higher than the standard rotation speed (for example, the rotation speed is 120% of the standard rotation speed). This increases the flow rate of water pumped by the tank circulation pump 94 .

At S<b>76 , the controller 150 opens the first gas introduction valve 106 . This restarts the introduction of air into the water flowing through the gas introduction mechanism 96 of the tank suction path 92 .

In S78, the controller 150 controls the tank circulation pump 94 so that the rotation speed of the tank circulation pump 94 becomes the standard rotation speed. This reduces the flow rate of water pumped by the tank circulation pump 94 .

In S<b>80 , control device 150 restarts driving of second pressurization pump 90 . As a result, the flow rate of water delivered by the first pressurization pump 88 and the second pressurization pump 90 increases. After S80, the process of FIG. 11 ends and the process proceeds to S46 (see FIG. 10).

In S46 of FIG. 10, the control device 150 determines whether or not the operating time of the microbubble generating operation has reached the set time. Here, the operating time of the microbubble generation operation is the elapsed time from the start of the microbubble generation operation. In the water heater 2 of the present embodiment, when the microbubble generation operation is executed independently without interlocking with the execution of the hot water filling operation, the set time is set to 10 minutes, for example. Unlike this, when the microbubble generation operation is executed in conjunction with the execution of the hot water filling operation, the set time is set to, for example, 30 minutes. If the operating time has not reached the set time (NO), the process returns to S44. When the operating time reaches the set time (YES), the process proceeds to S48.

At S<b>48 , the control device 150 stops the bathtub circulation pump 34 , the first pressure pump 88 , and the second pressure pump 90 to terminate the supply of air-dissolved water from the tank 52 to the bathtub 130 .

In S50, the controller 150 closes the first gas introduction valve 106 if the first gas introduction valve 106 is open. This completes the introduction of air into the water flowing through the gas introduction mechanism 96 of the tank suction path 92 .

In S52, the controller 150 closes the second gas introduction valve 108 if the second gas introduction valve 108 is open.

In S54, control device 150 executes a tank cleaning process. Specifically, the controller 150 opens the hot water filling valve 26 and starts heating the water by the first heat source machine 12 . As a result, as shown in FIG. 13, the water whose temperature is adjusted to the set temperature flows from the hot water supply path 18 to the circulation return path 32 via the hot water supply path 24 . The water that has flowed into the circulation return path 32 branches into a flow toward the upstream side (that is, the heat source return path 60) and a flow toward the downstream side (that is, the second heat source machine 14). Water flowing from the circulation return path 32 to the heat source return path 60 flows into the bathtub 130 via the communication path 66 , the second three-way valve 82 , the second bathtub water path 70 , and the bathtub adapter 132 . Further, the water flowing from the return circulation path 32 to the second heat source unit 14 includes the return circulation path 30, the heat source return path 68, the tank return path 74, the tank connection path 76, the tank 52, the tank return path 64, the first three-way valve 80, and the first bathtub water path. 62, flows into the bathtub 130 via the bathtub adapter 132; As a result, the inside of the tank 52, the tank suction path 92, and the tank connection path 76 are washed.

At S<b>56 , the controller 150 stops the tank circulation pump 94 . This completes the circulation of water between the tank 52 and the tank suction passage 92 and tank connection passage 76 . After S62, the process of FIG. 10 ends.

(Reheating operation)
The reheating operation is started when the user instructs the start of the reheating operation with the remote controller 154 . When starting the reheating operation, the control device 150 places the first three-way valve 80 in the third communication state and the second three-way valve 82 in the fifth communication state (see FIGS. 8 and 9). From this state, the controller 150 drives the bathtub circulation pump 34 and starts heating water by the second heat source machine 14 . As a result, as shown in FIG. 9, the water in the bathtub 130 flows through the bathtub adapter 132, the first bathtub water channel 62, the first three-way valve 80, the communication channel 66, the heat source return channel 60, and the circulation return channel 32 to the second heat source. sent to machine 14. The water heated by the second heat source machine 14 is returned to the bathtub 130 via the outward circulation path 30 , the outward heat source path 68 , the second three-way valve 82 , the second bathtub water passage 70 , and the bathtub adapter 132 . When the temperature detected by the return circulation thermistor 32a reaches or exceeds the set temperature, the control device 150 stops the bathtub circulation pump 34 and ends the water heating by the second heat source device 14 . After that, the control device 150 informs the user that the reheating operation is completed via the remote control 154, and ends the reheating operation.

(Modification)
In the above water heater 2, when executing the fine bubble generation operation, the control device 150 performs the process shown in FIG. 14 instead of executing the process shown in FIG. may be executed. In the following, differences between the processing shown in FIG. 14 and the processing shown in FIG. 11 will be described.

In the process shown in FIG. 14, first, in S82, the controller 150 waits until the elapsed time from opening the first gas introduction valve 106 in S38 (see FIG. 10) or S76 reaches the first predetermined time. The first predetermined time is the time assumed for the water level in the tank 52 to drop from the upper limit water level to the lower limit water level with the first gas introduction valve 106 and the second gas introduction valve 108 open. 10) is shorter than the set time. When the elapsed time from opening the first gas introduction valve 106 reaches the first predetermined time (YES), the process proceeds to S64.

Moreover, in the process shown in FIG. 14, after S66, the process proceeds to S84. In S84, the controller 150 waits until the elapsed time from closing the first gas introduction valve 106 in S64 reaches the second predetermined time. The second predetermined time is an assumed time until the water level in the tank 52 rises from the lower limit water level to the upper limit water level with the first gas introduction valve 106 and/or the second gas introduction valve 108 closed. (See FIG. 10). When the elapsed time after closing the first gas introduction valve 106 reaches the second predetermined time (if YES), the process proceeds to S70.

According to the processing shown in FIG. 14, opening and closing of the first gas introduction valve 106 and the second gas introduction valve 108 can be switched without using detection signals from the low water level electrode 52a and the high water level electrode 52b.

(Other modifications)
In the above-described water heater 2, the cold water mitigation process in S32 of FIG. 10 may be omitted in the microbubble generation operation that is performed in conjunction with the hot water filling operation.

In the water heater 2 described above, the tank cleaning process of S54 in FIG. 10 may be omitted.

In the above-described water heater 2, even if the operation time reaches the set time in the operation time determination process in S46 of FIG. Instead of proceeding to S48, the process may return to S44 and continue the microbubble generation operation.

In the water heater 2 described above, the order of the processes of S34 and S36 in FIG. 10 may be changed. That is, the control device 150 may drive the tank circulation pump 94 in S36 after the cold water relaxation process in S32, and then open the second gas introduction valve 108 in S34.

In the water heater 2 described above, the controller 150 may stop the tank circulation pump 94 after the first gas introduction valve 106 is closed in S64 of FIG. 11 or FIG. In this case, in subsequent S74, the controller 150 drives the tank circulation pump 94 again so that the rotation speed of the tank circulation pump 94 is higher than the standard rotation speed (for example, 120% of the standard rotation speed). ), the tank circulation pump 94 is controlled.

In the water heater 2 described above, the order of the processes of S70, S72, and S74 in FIG. 11 or 14 may be changed. For example, if YES in S68 of FIG. 11 or S84 of FIG. The rotation speed may be higher than the standard rotation speed, and then the second gas introduction valve 108 may be opened in S70.

In the water heater 2 described above, the control device 150 reduces the rotational speed of the first pressure pump 88 and/or the second pressure pump 90 instead of stopping the second pressure pump 90 in S72 of FIG. 11 or FIG. The rotation speed of the first pressurization pump 88 and/or the second pressurization pump 90 may be controlled so that the rotation speed is lower than the standard rotation speed (for example, the rotation speed is 80% of the standard rotation speed). . Even with such a configuration, it is possible to reduce the flow rate of the water pumped by the first pressurization pump 88 and the second pressurization pump 90 by the process of S72. In this case, instead of restarting the driving of the second pressure pump 90 in S80 of FIG. 11 or FIG. The rotation speed of the first pressurization pump 88 and/or the second pressurization pump 90 may be controlled so that the rotation speed becomes the standard rotation speed.

In the above-described water heater 2, when the fine bubble generation operation is executed in conjunction with the execution of the hot water filling operation, the end notification of hot water filling in S20 of FIG. 7 is not performed at the end of the hot water filling operation. You can do it while driving. More specifically, after the operating time of the microbubble generation operation reaches a predetermined notification time (for example, 2 minutes) for generating sufficient microbubbles in the water of the bathtub 130, the hot water filling end notification may be performed. With such a configuration, the timing for the user to enter the bathroom can be delayed, and the user can be prevented from entering the bathroom before sufficient microbubbles are generated in the water of the bathtub 130 .

In the water heater 2 described above, the user may be able to switch via the remote control 154 whether or not to perform the microbubble generation operation in conjunction with the execution of the hot water filling operation.

In the water heater 2 described above, air is introduced into the tank 52 , but gases such as carbon dioxide gas, hydrogen, and oxygen may be introduced into the tank 52 instead of air. In this case, a gas filling tank (not shown) filled with gas may be connected to the gas introduction port 110 of the gas introduction path 104 .

In the above-described water heater 2, a set amount of water is stored in the bathtub 130 based on the integrated amount of water detected by the water amount sensor 28 during the hot water filling operation. In contrast, the water heater 2 is provided with, for example, a water level sensor capable of detecting the water level of the bathtub 130, and in the hot water filling operation, based on the water level of the bathtub 130 detected by the water level sensor, the water level of the bathtub 130 is set. It is good also as a structure which stores the water of a water level.

In the water heater 2 described above, the heat source unit 10 is connected to the faucet 250 , and the pressurized air dissolving unit 50 is connected to the bathtub 130 . Alternatively, the heat source unit 10 may be connected to other heat utilization locations, and the air pressurized dissolving unit 50 may be connected to other liquid tanks.

In the above-described water heater 2, water is allowed to flow from the upstream side of the tank suction passage 92 to the downstream side of the tank suction passage 92 downstream of the tank circulation pump 94, and the water flow is allowed from the downstream side of the tank suction passage 92 to the upstream side. A check valve (not shown) may be provided to inhibit water flow to the side. By providing a check valve in the tank suction passage 92, even if the tank circulation pump 94 is stopped while the first pressure pump 88 and the second pressure pump 90 are being driven, the first pressure pump 88 , it is possible to prevent the water sent from the tank return path 74 by the second pressure pump 90 from flowing back through the tank suction path 92 .

In the water heater 2 described above, the gas introduction mechanism 96 is arranged upstream of the tank circulation pump 94 in the tank suction passage 92 . Alternatively, the gas introduction mechanism 96 may be arranged downstream of the tank circulation pump 94 in the tank suction path 92 .

In the water heater 2 described above, the downstream end of the tank return path 74 and the downstream end of the tank suction path 92 are connected to the tank 52 via a common tank connection path 76 . In contrast, as shown in FIG. 15, the air pressurized dissolving unit 50 does not have a tank connecting passage 76, and the downstream end of the tank return passage 74 (hereinafter also referred to as the inlet port 74a) and the tank suction passage. The downstream end of 92 (hereinafter also referred to as inlet 92b) may be configured to connect to tank 52 separately. In this case, the water flowing through the tank return path 74 flows into the tank 52 through the inlet 74a, and the water flowing through the tank suction path 92 flows into the tank 52 through the inlet 92b.

As described above, in one or more embodiments, the water heater 2 (an example of a microbubble generator) includes a tank 52 for pressurizing and dissolving air (an example of a gas) in water (an example of a liquid), and a tank 52, a tank return path 74 and a tank connection path 76 (an example of a tank supply path), and a first pressurization pump 88 and a second pressurization pump 90 (an example of a pressurization pump) provided in the tank return path 74. , a tank outward passage 64 for discharging water in which air is pressurized and dissolved from the tank 52 to a bathtub 130 (example of a liquid tank), a first bathtub water passage 62, a bathtub adapter 132 (an example of a tank discharge passage), and a bathtub adapter 132. A microbubble generating nozzle 142 for generating microbubbles by decompressing water in which air is pressurized and dissolved, a tank forward passage 64, a first bathtub water passage 62, and a bathtub adapter 132 are provided separately. A tank suction passage 92 for sending water from an outflow port 92a connected to the tank 52 to an inflow port 76a connected to the tank 52; a tank circulation pump 94 , a gas introduction mechanism 96 provided in the tank suction passage 92 , and a controller 150 . The gas introduction mechanism 96 includes a venturi tube 102 (an example of a decompression unit) through which water is decompressed, a gas introduction port 110 through which air is introduced by the negative pressure of the water in the venturi tube 102, the venturi tube 102 and the gas introduction port. a first gas introduction valve 106 provided in the gas introduction path 104 for opening and closing the gas introduction path 104; and a first gas introduction valve 106 and a gas introduction port in the gas introduction path 104. 110 and includes a second gas introduction valve 108 for opening and closing the gas introduction path 104 . The first gas introduction valve 106 is configured to receive a force in the direction of opening the first gas introduction valve 106 when the negative pressure of water in the venturi tube 102 acts. The second gas introduction valve 108 is configured to receive a force in the direction of closing the second gas introduction valve 108 when the negative pressure of water in the venturi tube 102 acts. 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 and the tank connection path 76 to the tank 52, and from the tank 52 to the tank outward path 64, It is possible to perform a fine bubble generation operation in which water in which air is pressurized and dissolved is supplied to the bathtub 130 via the first bathtub water channel 62 and the bathtub adapter 132 . The controller 150 causes the tank circulation pump 94 to circulate the water in the tank 52 through the tank suction path 92 and the tank connection path 76 during execution of the microbubble generation operation, thereby applying a negative pressure to the venturi tube 102 of the gas introduction mechanism 96. Generating tank circulation operation can be executed. When opening both the first gas introduction valve 106 and the second gas introduction valve 108 from the closed state, the control device 150 first opens the second gas introduction valve 108 and then opens the first gas introduction valve. It is configured to open the valve 106 .

In the water heater 2 described above, even during the microbubble generation operation, the tank circulation operation is performed with the first gas introduction valve 106 and the second gas introduction valve 108 opened, so that the gas introduction mechanism 96 Air can be introduced at to supply the tank 52 with air. Therefore, it is not necessary to interrupt the microbubble generation operation to supply air to the tank 52, and the microbubble generation operation can be continued. With such a configuration, fine air bubbles can be stably and continuously generated in the water in the bathtub 130 .

Further, in the above-described water heater 2, the gas introduction path 104 is provided with the first gas introduction valve 106 and the second gas introduction valve 108, and the second gas introduction valve 108 is provided with the first gas introduction valve 106 and the gas introduction port. 110, and when the negative pressure of water in the venturi tube 102 acts on the first gas introduction valve 106, a force acts in the direction of opening the first gas introduction valve 106, and the second gas introduction valve A force acts on 108 in a direction to close the second gas introduction valve 108 when the negative pressure of water in the venturi tube 102 acts. For this reason, for example, when both the first gas introduction valve 106 and the second gas introduction valve 108 are opened from the closed state while the fine bubble generation operation and the tank circulation operation are being performed at the same time, If the first gas introduction valve 106 is opened, when the second gas introduction valve 108 is subsequently opened, the negative pressure of the water in the venturi tube 102 acts on the second gas introduction valve 108, and the second gas introduction valve 108 may not work smoothly. As in the above configuration, when both the first gas introduction valve 106 and the second gas introduction valve 108 are opened from the closed state while the fine bubble generation operation and the tank circulation operation are being performed at the same time, By opening the second gas introduction valve 108 first, the negative pressure of the water in the venturi tube 102 can be suppressed from acting on the second gas introduction valve 108, and the second gas introduction valve 108 can be operated smoothly. can be made

In the water heater 2, the control device 150, when opening the first gas introduction valve 106 from the closed state during execution of the fine bubble generation operation, first pressurizes the first pressurizing pump 88 and the second pressurizing pump 88. The flow rate of the pump 90 is changed from a first flow rate (for example, the flow rate when both the first pressure pump 88 and the second pressure pump 90 are driven) to a second flow rate (for example, the first pressure pump 88 is driven, the flow rate is reduced to the flow rate when the second pressurizing pump 90 is stopped, and then the first gas introduction valve 106 is opened. The first flow rate can also be said to be the flow rate of the first pressurization pump 88 and the second pressurization pump 90 when the microbubble generating operation is performed with the first gas introduction valve 106 closed. The flow rate can also be said to be the flow rate of the first pressurizing pump 88 and the second pressurizing pump 90 when both the microbubble generation operation and the tank circulation operation are performed with the first gas introduction valve 106 open. Alternatively, the first flow rate can be said to be the flow rate of the first pressurizing pump 88 and the second pressurizing pump 90 when the water level of the tank 52 rises during the fine bubble generation operation. The flow rate can also be said to be the flow rate of the first pressurizing pump 88 and the second pressurizing pump 90 when the water level of the tank 52 decreases during both the fine bubble generation operation and the tank circulation operation.

When the microbubble generating operation is executed, if the flow rates of the first pressurizing pump 88 and the second pressurizing pump 90 are large, the pressure in the tank 52 increases, and the water pressure in the venturi tube 102 of the gas introduction mechanism 96 also increases. Become. That is, the negative pressure of water in the venturi tube 102 is reduced. Conversely, when the flow rates of the first pressurizing pump 88 and the second pressurizing pump 90 are small, the pressure in the tank 52 becomes low, and the water pressure in the venturi tube 102 of the gas introduction mechanism 96 also becomes low. That is, the negative pressure of water in the venturi tube 102 increases. The negative pressure of the water in the venturi tube 102 acts on the first gas introduction valve 106 in the direction of opening the first gas introduction valve 106 . The lower the water pressure, the smoother the first gas introduction valve 106 can be operated. According to the above configuration, when opening the first gas introduction valve 106 from the closed state, the flow rates of the first pressurizing pump 88 and the second pressurizing pump 90 are first reduced from the first flow rate to the second flow rate. By reducing the flow rate, the pressure of the water in the venturi tube 102 of the gas introduction mechanism 96 is lowered, and then the first gas introduction valve 106 is opened, so the first gas introduction valve 106 can be operated smoothly. .

In the water heater 2, the controller 150 first reduces the flow rate of the tank circulation pump 94 to the third flow rate (for example, , the flow rate when the tank circulation pump 94 is driven at a standard rotation speed) to a fourth flow rate larger than the third flow rate (for example, the flow rate when the tank circulation pump 94 is driven at a high rotation speed), and then It is configured to open the first gas introduction valve 106 . The third flow rate is the flow rate of the tank circulation pump 94 when the fine bubble generation operation is performed with the first gas introduction valve 106 closed (the tank circulation operation is performed with the first gas introduction valve 106 closed). If it is performed, it is the flow rate of the tank circulation pump 94 at that time, and if the tank circulation operation is not performed with the first gas introduction valve 106 closed, it is zero). The flow rate can also be said to be the flow rate of the tank circulation pump 94 when both the fine bubble generating operation and the tank circulation operation are performed with the first gas introduction valve 106 open. Alternatively, the third flow rate can be the flow rate of the tank circulation pump 94 when the water level of the tank 52 is rising during the fine bubble generation operation, and the fourth flow rate is the fine bubble generation operation and the tank It can also be said that this is the flow rate of the tank circulation pump 94 when the water level of the tank 52 is decreasing during both circulation operations.

When the tank circulation operation is executed, if the flow rate of the tank circulation pump 94 is small, the water pressure in the venturi tube 102 of the gas introduction mechanism 96 increases. That is, the negative pressure of water in the venturi tube 102 is reduced. Conversely, when the flow rate of the tank circulation pump 94 is large, the water pressure in the venturi tube 102 of the gas introduction mechanism 96 becomes low. That is, the negative pressure of water in the venturi tube 102 increases. The negative pressure of the water in the venturi tube 102 acts on the first gas introduction valve 106 in the direction of opening the first gas introduction valve 106 . The lower the water pressure, the smoother the first gas introduction valve 106 can be operated. According to the above configuration, when the first gas introduction valve 106 is opened from the closed state, the flow rate of the tank circulation pump 94 is first increased from the third flow rate to the fourth flow rate, thereby introducing the gas. Since the water pressure in the venturi tube 102 of the mechanism 96 is lowered and then the first gas introduction valve 106 is opened, the first gas introduction valve 106 can be operated smoothly.

In the water heater 2, when both the first gas introduction valve 106 and the second gas introduction valve 108 are closed from the open state, the control device 150 first closes the first gas introduction valve 106, and then closes the first gas introduction valve 106. is configured to close the second gas introduction valve 108 immediately.

In the water heater 2 described above, the gas introduction passage 104 is provided with the first gas introduction valve 106 and the second gas introduction valve 108 . When the negative pressure of the water in the venturi tube 102 acts on the first gas introduction valve 106, a force acts in the direction of opening the first gas introduction valve 106, and the second gas introduction valve 108 , when the negative pressure of water in the venturi tube 102 acts, a force acts in the direction of closing the second gas introduction valve 108 . For this reason, for example, when both the first gas introduction valve 106 and the second gas introduction valve 108 are closed from the open state when the fine bubble generation operation and the tank circulation operation are being performed at the same time, If the second gas introduction valve 108 is closed, the negative pressure of the water in the venturi tube 102 acts on the second gas introduction valve 108 when the second gas introduction valve 108 is closed, and the valve of the second gas introduction valve 108 The body 108c may strongly collide with the valve seat 108b, causing noise and damage to the second gas introduction valve 108. As in the above configuration, when both the first gas introduction valve 106 and the second gas introduction valve 108 are closed from the open state, by first closing the first gas introduction valve 106, after that When the second gas introduction valve 108 is closed, the negative pressure of the water in the venturi tube 102 can be suppressed from acting on the second gas introduction valve 108, and the valve body 108c of the second gas introduction valve 108 is the valve seat. It is possible to suppress the generation of noise and damage to the second gas introduction valve 108 due to strong collision with 108b.

Although each embodiment has 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 in the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims as of the filing. In addition, the techniques exemplified in this specification or drawings can simultaneously achieve a plurality of purposes, and achieving one of them has technical utility in itself.

2: Water heater 10: Heat source unit 12: First heat source device 14: Second heat source device 16: Water supply path 18: Hot water outlet path 18a: Hot water outlet temperature thermistor 20: Bypass path 22: Bypass servo 24: Hot water pouring path 26: Hot water filling Valve 28 : Water volume sensor 30 : Outgoing circulation path 30a : Outgoing circulation thermistor 32 : Returning circulation path 32a : Returning circulation thermistor 34 : Bathtub circulation pump 36 : Water flow switch 50 : Air pressurized dissolving unit 52 : Tank 52a : Low water level electrode 52b : High Water level electrode 52c : Earth electrode 60 : Heat source return path 62 : First bathtub water path 64 : Tank outward path 66 : Communication path 68 : Heat source outward path 70 : Second bathtub water path 74 : Tank return path 74a : Inlet 76 : Tank connection path 76a : Flow Inlet 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 suction passage 92a : Outlet 92b : Inlet 94: Tank circulation pump 96: Gas introduction mechanism 98: Water inlet pipe 100: Water outlet pipe 102: Venturi pipe 104: Gas introduction passage 104a: First gas introduction passage 104b: Second gas introduction passage 104c: Third gas introduction passage 106: First gas introduction valve 106a: valve chamber 106b: valve seat 106c: valve element 106d: plunger 106e: coil 106f: spring 108: second gas introduction valve 108a: valve chamber 108b: valve seat 108c: valve element 108d: plunger 108e: Coil 108f : Spring 110 : Gas inlet 130 : Bathtub 130a : Wall 132 : Bathtub adapter 132a : Front surface 132b : Lower surface 134a : First outlet 134b : First suction port 134c : Second suction port 134d : Second outlet 136: first water channel 136a: first discharge channel 136b: first suction channel 138: second water channel 138a: second discharge channel 138b: second suction channel 140a: non-return portion 140b: non-return portion 140c: non-return portion 140d : Non-return part 142 : Fine bubble generating nozzle 150 : Control device 152 : Memory 154 : Remote controller 200 : Water supply source 250 : Callan

Claims (5)

a tank for pressurizing and dissolving a gas in a liquid;
a tank supply path for supplying the liquid to the tank;
a pressurizing pump provided in the tank supply channel;
a tank discharge path for discharging the liquid in which the gas is pressurized and dissolved from the tank to the liquid tank;
a microbubble generating nozzle provided in the tank discharge passage for generating microbubbles by depressurizing the liquid in which the gas is pressurized and dissolved;
a tank circulation path provided separately from the tank discharge path for sending the liquid from an outlet connected to the tank to an inlet connected to the tank;
a tank circulation pump provided in the tank circulation path;
a gas introduction mechanism provided in the tank circulation path;
Equipped with a control device,
The gas introduction mechanism is
a decompression unit for decompressing and passing the liquid;
a gas introduction port for introducing the gas by the negative pressure of the liquid in the decompression unit;
a gas introduction path communicating between the decompression unit and the gas introduction port;
a first gas introduction valve provided in the gas introduction path for opening and closing the gas introduction path;
a second gas introduction valve provided between the first gas introduction valve and the gas introduction port in the gas introduction path and opening and closing the gas introduction path;
The first gas introduction valve is configured to receive a force in the direction of opening the first gas introduction valve when negative pressure of the liquid in the decompression unit acts,
The second gas introduction valve is configured to receive a force in the direction of closing the second gas introduction valve when the negative pressure of the liquid in the decompression unit acts,
The control device drives the pressure pump to pressurize and supply the liquid from the tank supply passage to the tank, and pressurize the gas from the tank to the liquid tank through the tank discharge passage. It is possible to perform a microbubble generation operation that supplies the dissolved liquid,
The control device causes the tank circulation pump to circulate the liquid in the tank through the tank circulation path during execution of the fine bubble generation operation, thereby generating a negative pressure in the decompression unit of the gas introduction mechanism. Circulating operation can be performed,
When opening both the first gas introduction valve and the second gas introduction valve from a closed state, the control device first opens the second gas introduction valve, and then opens the first gas introduction valve. A microbubble generator configured to open an inlet valve. When the first gas introduction valve is opened from the closed state during execution of the fine bubble generation operation, the control device first reduces the flow rate of the pressure pump from the first flow rate to the first flow rate. 2. The microbubble generator of claim 1, wherein the flow rate is reduced to a second flow rate smaller than the flow rate, and then the first gas introduction valve is opened. When the first gas introduction valve is opened from the closed state during execution of the tank circulation operation, the control device first reduces the flow rate of the tank circulation pump from the third flow rate to the third flow rate. 3. The microbubble generator according to claim 1 or 2, configured to increase the flow rate to a large fourth flow rate and then open the first gas introduction valve. When closing both the first gas introduction valve and the second gas introduction valve from an open state, the control device first closes the first gas introduction valve and then closes the second gas introduction valve. 4. Microbubble generator according to any one of claims 1 to 3, configured to close the introduction valve. the liquid is water,
5. The microbubble generator according to any one of claims 1 to 4, wherein the liquid tank is a bathtub used by a user for bathing.

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