JP7709924B2 - Microbubble generator - Google Patents

Description

This specification relates to a microbubble generating device.

Patent Document 1 discloses a fine bubble generating device including a tank for pressurizing and dissolving a gas in a liquid, a tank supply path for supplying the liquid to the tank, a pressure pump provided in the tank supply path, a tank discharge path for discharging the liquid in which the gas is pressurized and dissolved from the tank to a liquid tank, a fine bubble generating nozzle provided in the tank discharge path for reducing the pressure of the liquid in which the gas is pressurized and dissolved to generate fine bubbles, 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, two liquid level electrodes capable of detecting whether the liquid level in the tank is equal to or higher than a predetermined liquid level, and a control device. The gas introduction mechanism includes a pressure reduction section for reducing the pressure of the liquid and passing it through, a gas introduction port for introducing the gas by the negative pressure of the liquid in the pressure reduction section, and a gas introduction valve for opening and closing the gas introduction port. The control device can perform a fine bubble generating operation in which the pressurizing pump is driven to pressurize and supply the liquid from the tank supply path to the tank, and the liquid in which the gas is pressurized and dissolved is supplied from the tank to the liquid tank via the tank discharge path. During the fine bubble generating operation, the control device drives the tank circulation pump to circulate the liquid in the tank through the tank circulation path, thereby supplying the gas introduced from the gas inlet to the tank, and controls the opening and closing operation of the gas introduction valve based on information regarding whether the liquid level in the tank detected by one of the two liquid level electrodes is equal to or higher than the lower liquid level and information regarding whether the liquid level in the tank detected by the other of the two liquid level electrodes is equal to or higher than the upper liquid level.

JP 2015-127052 A

In a fine bubble generator, it may be necessary to reduce the amount of information related to the liquid level in the tank in order to ensure rapidity in the judgment process related to the opening and closing of the gas introduction valve. In the fine bubble generator of Patent Document 1, the control device is configured to control the opening and closing operation of the gas introduction valve based on information related to whether the liquid level in the tank is equal to or higher than the lower liquid level and information related to whether the liquid level in the tank is equal to or higher than the upper liquid level. In such a fine bubble generator, the amount of information related to the liquid level in the tank is relatively large, and the judgment process related to the opening and closing of the gas introduction valve may be lacking in rapidity. This specification provides a technology that can reduce the amount of information related to the liquid level in the tank and ensure rapidity in the judgment process related to the opening and closing of the gas introduction valve. In this specification, for a fine bubble generator equipped with two liquid level electrodes, the two liquid level electrodes may be described as "lower liquid level electrode" and "upper liquid level electrode". Here, the "lower liquid level" is a liquid level lower than the "upper liquid level".

The microbubble generating device disclosed in this specification includes a tank for pressurizing and dissolving a gas in a liquid, a tank supply path for supplying the liquid to the tank, a pressure pump provided in the tank supply path, a tank discharge path for discharging the liquid in which the gas is pressurized and dissolved from the tank to a liquid tank, a microbubble generating nozzle provided in the tank discharge path for reducing the pressure of the liquid in which the gas is pressurized and dissolved to generate microbubbles, 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, a liquid level electrode capable of detecting whether the liquid level in the tank is equal to or higher than a predetermined liquid level, and a control device. The gas introduction mechanism includes a pressure reduction section for reducing the pressure of the liquid and passing it through, a gas introduction port for introducing the gas by the negative pressure of the liquid in the pressure reduction section, and a gas introduction valve for opening and closing the gas introduction port. The control device can perform a fine bubble generating operation in which the pressurizing pump is driven to pressurize and supply the liquid from the tank supply path to the tank, and the liquid in which the gas is pressurized and dissolved is supplied from the tank to the liquid tank via the tank discharge path. During the fine bubble generating operation, the control device drives the tank circulation pump to circulate the liquid in the tank through the tank circulation path, thereby supplying the gas introduced from the gas inlet to the tank, and controls the opening and closing of the gas introduction valve based on information on whether the liquid level in the tank detected by the liquid level electrode is equal to or higher than a predetermined liquid level.

Another fine bubble generating device disclosed in this specification includes a tank for pressurizing and dissolving a gas in a liquid, a tank supply path for supplying the liquid to the tank, a pressure pump provided in the tank supply path, a tank discharge path for discharging the liquid in which the gas is pressurized and dissolved from the tank to a liquid tank, a fine bubble generating nozzle provided in the tank discharge path for reducing the pressure of the liquid in which the gas is pressurized and dissolved to generate fine bubbles, 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, a single liquid level electrode capable of detecting whether the liquid level in the tank is equal to or higher than a predetermined liquid level, and a control device. The gas introduction mechanism includes a pressure reduction section for reducing the pressure of the liquid and passing it through, a gas introduction port for introducing the gas by the negative pressure of the liquid in the pressure reduction section, and a gas introduction valve for opening and closing the gas introduction port. The control device can perform a fine bubble generating operation in which the pressurized pump is driven to pressurize and supply the liquid from the tank supply path to the tank, and the liquid in which the gas is pressurized and dissolved is supplied from the tank to the liquid tank via the tank discharge path. During the fine bubble generating operation, the control device drives the tank circulation pump to circulate the liquid in the tank through the tank circulation path, thereby supplying the gas introduced from the gas inlet to the tank, and controls the opening and closing of the gas introduction valve based on information regarding whether the liquid level in the tank detected by the single liquid level electrode is equal to or higher than a predetermined liquid level.

According to the above configuration, the control device is configured to control the opening and closing operation of the gas introduction valve based on information regarding whether the liquid level in the tank is equal to or higher than a predetermined liquid level, which is detected by one liquid level electrode. This reduces the amount of information regarding the liquid level in the tank, and ensures rapid decision-making regarding the opening and closing of the gas introduction valve.

In one or more embodiments, when the control device detects that the liquid level in the tank is lower than the predetermined liquid level with the gas introduction valve open during the execution of the fine bubble generating operation, the control device may close the gas introduction valve, maintain the gas introduction valve closed until a first predetermined time has elapsed since the gas introduction valve was closed, and open the gas introduction valve after the first predetermined time has elapsed.

In a micro-bubble generator, droplets scattered from the liquid surface of the tank may adhere to the level electrode, causing slime to form on the level electrode. If slime forms on the level electrode, the tank's liquid level may be erroneously detected. For example, if a micro-bubble generator has a lower level electrode and an upper level electrode, and the control device controls the opening and closing operation of the gas introduction valve so that the tank's liquid level fluctuates between the lower level and the upper level, the upper level electrode is hardly immersed in the liquid. As a result, the upper level electrode cannot suppress the generation of slime, and the tank's liquid level may be erroneously detected. With the above configuration, the level electrode can be frequently immersed in liquid during the micro-bubble generating operation, thereby suppressing the generation of slime on the level electrode. As a result, erroneous detection of the tank's liquid level can be suppressed.

In one or more embodiments, the control device may determine, during the execution of the fine bubble generating operation, the elapsed time from when the gas introduction valve, which is in the closed state, is opened until the liquid level electrode detects that the liquid level in the tank is lower than the predetermined liquid level and the gas introduction valve is closed as the intake time, and if the intake time exceeds an upper intake time limit, reduce the rotation speed of the pressure pump when the pressure pump is subsequently driven.

If the intake time is too long, it is assumed that either too much liquid is supplied to the tank or too little gas is introduced by the gas introduction mechanism. Furthermore, the higher the rotation speed of the pressurizing pump, the greater the amount of liquid supplied to the tank, and the lower the rotation speed of the pressurizing pump, the less the amount of liquid supplied to the tank. With the above configuration, if the intake time exceeds the upper intake time limit, i.e., if the intake time is too long, the rotation speed of the pressurizing pump can be reduced to reduce the amount of liquid supplied to the tank and shorten the intake time.

In one or more embodiments, the control device may, during the execution of the fine bubble generating operation, determine as an intake time the elapsed time from when the gas introduction valve, which is in the closed state, is opened until the liquid level in the tank is detected by the liquid level electrode to be lower than the predetermined liquid level and the gas introduction valve is closed, and if the intake time falls below a lower limit intake time, increase the rotation speed of the pressure pump when driving the pressure pump thereafter.

If the intake time is too short, it is assumed that either the amount of liquid supplied to the tank is too small or the amount of gas introduced by the gas introduction mechanism is too large. With the above configuration, if the intake time falls below the lower limit intake time, i.e., if the intake time is too short, the rotation speed of the pressurizing pump is increased to increase the amount of liquid supplied to the tank and extend the intake time.

In one or more embodiments, the control device, during the execution of the fine bubble generating operation, may determine as an intake time the elapsed time from when the gas introduction valve is opened from the closed state until the liquid level electrode detects that the liquid level in the tank is lower than the predetermined liquid level and closes the gas introduction valve, and if the intake time exceeds an upper intake time limit, may increase the rotation speed of the tank circulation pump when driving the tank circulation pump thereafter with the gas introduction valve open.

If the intake time is too long, it is assumed that either too much liquid is supplied to the tank or too little gas is introduced by the gas introduction mechanism. Furthermore, when the gas introduction valve is open, the higher the rotation speed of the tank circulation pump, the greater the amount of gas introduced by the gas introduction mechanism, and the lower the rotation speed of the tank circulation pump, the less gas is introduced by the gas introduction mechanism. With the above configuration, if the intake time exceeds the upper intake time limit, i.e., if the intake time is too long, the rotation speed of the tank circulation pump can be increased to increase the amount of gas introduced by the gas introduction mechanism and shorten the intake time.

In one or more embodiments, the control device, during the execution of the fine bubble generating operation, may determine as an intake time the elapsed time from when the gas introduction valve, which is in the closed state, is opened until the liquid level in the tank is detected by the liquid level electrode to be lower than the predetermined liquid level and the gas introduction valve is closed, and if the intake time falls below a lower limit intake time, the rotation speed of the tank circulation pump may be reduced when the tank circulation pump is subsequently driven with the gas introduction valve open.

If the intake time is too short, it is assumed that either the amount of liquid supplied to the tank is too small or the amount of gas introduced by the gas introduction mechanism is too large. With the above configuration, if the intake time falls below the lower limit intake time, i.e., if the intake time is too short, the rotation speed of the tank circulation pump is reduced to reduce the amount of gas introduced by the gas introduction mechanism and extend the intake time.

In one or more embodiments, the control device may determine whether or not a stop condition for stopping the fine bubble generating operation is satisfied during the execution of the fine bubble generating operation, and may execute a stop process for stopping the fine bubble generating operation when the stop condition is satisfied. When the stop process is executed, the control device may open the gas introduction valve while driving the pressurizing pump and the tank circulation pump, and when the liquid level electrode detects that the liquid level in the tank is lower than the predetermined liquid level while the gas introduction valve is open, close the gas introduction valve, and maintain the gas introduction valve closed for a second predetermined time that is longer than the first predetermined time from when the gas introduction valve is closed, and after the second predetermined time has elapsed, stop the pressurizing pump and the tank circulation pump to stop the fine bubble generating operation.

According to the above configuration, the micro-bubble generating operation can be stopped while the level electrode is immersed in the liquid. This can suppress the generation of slime on the level electrode and prevent erroneous detection of the tank's liquid level. Furthermore, according to the above configuration, when the micro-bubble generating operation is stopped, the level electrode is immersed in the liquid up to a portion above the portion that is immersed in the liquid during normal operation. Therefore, the generation of slime on the level electrode can be more appropriately suppressed.

In one or more embodiments, when the control device detects that the liquid level in the tank is equal to or higher than the predetermined liquid level with the gas introduction valve closed during the execution of the fine bubble generating operation, the control device may open the gas introduction valve, maintain the gas introduction valve open for a period from when the gas introduction valve is opened until a third predetermined time has elapsed, and close the gas introduction valve after the third predetermined time has elapsed.

For example, if the micro-bubble generator is equipped with a lower liquid level electrode and an upper liquid level electrode, and the control device controls the opening and closing operation of the gas introduction valve so that the liquid level in the tank fluctuates between the lower liquid level and the upper liquid level, the length of the lower liquid level electrode needs to be relatively long. In this case, this may lead to an increase in the weight of the entire device. With the above configuration, the length of the liquid level electrode can be made relatively short. This allows the weight of the entire device to be reduced.

In one or more embodiments, the liquid may be water. The liquid tank may be a bathtub that a user uses to bathe.

The above configuration allows a micro-bubble generator that generates micro-bubbles in the water in a bathtub used by a user for bathing to reduce the amount of information related to the tank's water level and ensure rapid decision-making regarding the opening and closing of the gas introduction valve.

FIG. 2 is a diagram showing a schematic configuration of a water heating device 2 according to the first to third embodiments. 10 is a diagram showing a schematic example of the flow of water in the bathtub adapter 132 of the hot water device 2 of Examples 1 to 3. FIG. 13 is a diagram showing another example of water flow in the bathtub adapter 132 of the hot water device 2 of Examples 1 to 3. FIG. 3 is a diagram showing a schematic example of a water flow in the hot water device 2 of the first to third embodiments. FIG. 10 is a diagram showing another example of the water flow in the hot water device 2 of the first to third embodiments. FIG. FIG. 10 is a diagram showing a schematic diagram of still another example of the water flow in the hot water device 2 of the first to third embodiments. 4 is a flowchart of a process executed by a control device 150 during a fine bubble generating operation of the hot water device 2 of the first embodiment. 11 is a flowchart of a stop process executed by the control device 150 in the process shown in FIG. 7, the process shown in FIG. 9, or the process shown in FIG. 10 during the fine bubble generating operation of the hot water device 2 in any one of the first to third embodiments. 10 is a flowchart of a process executed by a control device 150 during a fine bubble generating operation of a hot water device 2 of a second embodiment. 13 is a flowchart of a process executed by a control device 150 during a fine bubble generating operation of a hot water device 2 of a third embodiment.

Example 1
1, the hot water device 2 of this embodiment includes a heat source unit 10, an air pressurized dissolution unit 50, a bathtub adapter 132, and a control device 150. The hot water device 2 heats water supplied from a water supply source 200 such as a tap, and can supply the water heated to a desired temperature to a faucet 250 installed in a kitchen or the like, or to a bathtub 130 installed in a bathroom. The hot water device 2 can also generate fine air bubbles in the water in the bathtub 130 that a user uses for bathing.

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

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

The upstream end of the bypass passage 20 is connected to the water supply passage 16, and the downstream end of the bypass passage 20 is connected to the hot water outlet passage 18. The bypass servo 22 is provided at the point where the bypass passage 20 connects to the water supply passage 16. The bypass servo 22 can adjust the ratio of the flow rate of water flowing from the water supply passage 16 to the hot water outlet passage 18 via the first heat source unit 12 and the flow rate of water flowing from the water supply passage 16 to the hot water outlet passage 18 via the bypass passage 20 by adjusting the opening degree of the built-in valve body. By adjusting the opening degree of the bypass servo 22, the hot water outlet passage 18 downstream of the point where the bypass passage 20 connects is supplied with water whose temperature has been adjusted to the desired temperature by mixing high-temperature water flowing from the first heat source unit 12 and low-temperature water flowing from the bypass passage 20 at a desired ratio. The hot water outlet passage 18 downstream of the point where the bypass passage 20 connects is provided with an outlet hot water temperature thermistor 18a that detects the temperature of the water in the hot water outlet passage 18.

The upstream end of the molten metal pouring passage 24 is connected to the molten metal outlet passage 18 downstream of the point where the bypass passage 20 is connected, and the downstream end of the molten metal pouring passage 24 is connected to the circulation return passage 32. The molten metal filling valve 26 is provided in the molten metal pouring passage 24 and opens and closes the molten metal pouring passage 24. The molten metal filling valve 26 is normally kept in a closed state. The water volume sensor 28 is provided in the molten metal pouring passage 24 and detects the amount of water flowing through the molten metal pouring passage 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 pressurized dissolution unit 50, and the downstream end of the circulation return path 32 is connected to the second heat source device 14. The upstream end of the circulation outward path 30 is connected to the second heat source device 14, and the downstream end of the circulation outward path 30 is connected to the heat source outward path 68 (details will be described later) of the air pressurized dissolution unit 50. The second heat source device 14 is a combustion heat source device that heats water by, for example, burning gas. The second heat source device 14 heats the water flowing in from the circulation return path 32 and sends the heated water to the circulation outward path 30. A circulation return path thermistor 32a that detects the temperature of the water in the circulation return path 32 is provided near the upstream end of the circulation return path 32. A circulation outward path thermistor 30a that detects the temperature of the water in the circulation outward path 30 is provided near the downstream end of the circulation outward path 30.

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

(Configuration of the air pressurized dissolving unit 50)
The air pressurization dissolution 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 outward path 64, a connecting passage 66, a first three-way valve 80, a second three-way valve 82, a check valve 84, a tank water supply valve 86, a first pressurization pump 88, a second pressurization pump 90, a tank circulation path 92, a tank circulation pump 94, and a gas introduction mechanism 96.

The tank 52 is used to generate air-dissolved water by pressurizing and dissolving air in water. The tank 52 can store water inside. Inside the tank 52, a water level electrode 54 for detecting the water level in the tank 52 and an earth electrode (not shown) are installed. When the water level electrode 54 comes into contact with the surface of the water stored in the tank 52, a current flows between the water level electrode 54 and the earth electrode, and an ON signal is output to the control device 150. In other words, the water level electrode 54 is configured to be able to detect whether the water level in the tank 52 is equal to or higher than a predetermined water level. Hereinafter, the water level in the tank 52 detected by the water level electrode 54 may be referred to as the "boundary water level."

One end of the heat source return line 60 is connected to the communication passage 66, and the other end of the heat source return line 60 is connected to the circulation return line 32 of the heat source unit 10. The communication passage 66 connects the first three-way valve 80 and the second three-way valve 82. The first three-way valve 80 is connected to the communication passage 66, the first bathtub water passage 62, and the tank forward line 64. The first three-way valve 80 can be switched between a first communication state (see FIG. 6) in which the tank forward line 64 and the first bathtub water passage 62 are connected, a second communication state (see FIG. 1) in which the tank forward line 64 and the communication passage 66 are connected, and a third communication state (see FIG. 4 and FIG. 5) in which the first bathtub water passage 62, the tank forward line 64, and the communication passage 66 are connected. The upstream end of the tank outgoing line 64 is connected to the bottom of the tank 52, and the downstream end of the tank outgoing line 64 is connected to the first three-way valve 80. The tank outgoing line 64 is provided with a check valve 84 that allows water to flow from the tank 52 to the first three-way valve 80 and prohibits water from flowing from the first three-way valve 80 to the tank 52. One end of the first bathtub water passage 62 is connected to the first three-way valve 80, and the other end of the first bathtub water passage 62 is connected to the bathtub adapter 132.

One end of the heat source outgoing line 68 is connected to the circulation outgoing line 30 of the heat source unit 10, and the other end of the heat source outgoing line 68 is connected to the second three-way valve 82. The second three-way valve 82 is connected to the communication passage 66, the heat source outgoing line 68, and the second bathtub water passage 70. The second three-way valve 82 can switch between a fourth communication state (see FIG. 6) in which the second bathtub water passage 70 and the communication passage 66 are connected, and a fifth communication state (see FIG. 1, FIG. 4, FIG. 5) in which the heat source outgoing line 68 and the second bathtub water passage 70 are connected. One end of the second bathtub water passage 70 is connected to the second three-way valve 82, and the other end of the second bathtub water passage 70 is connected to the bathtub adapter 132.

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

The upstream end of the tank circulation path 92 (hereinafter also referred to as the outlet 92a) is connected to the bottom of the tank 52, and the downstream end of the tank circulation path 92 is connected to the tank return path 74 downstream of the second pressure pump 90. The water level at the point where the outlet 92a of the tank circulation path 92 is connected to the tank 52 is lower than the boundary water level. The tank circulation pump 94 is provided in the tank circulation path 92. The tank circulation pump 94 draws water from the tank 52 into the tank circulation path 92 through the outlet 92a, and discharges water from the tank circulation path 92 into the tank 52 through the water supply port 74a at the downstream end of the tank return path 74.

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

(Configuration of bathtub adaptor 132)
Next, the bathtub adaptor 132 provided on the wall 130a of the bathtub 130 will be described with reference to Figures 2 and 3. Figure 2 shows the flow of water in the bathtub adaptor 132 when water flows from the first bathtub water channel 62 toward the bathtub 130 and from the bathtub 130 toward the second bathtub water channel 70 (for example, the state shown in Figure 6). Figure 3 shows the flow of water in the bathtub adaptor 132 when water flows from the bathtub 130 toward the first bathtub water channel 62 and from the second bathtub water channel 70 toward the bathtub 130 (for example, the state shown in Figure 5).

The bathtub adapter 132 has a first water passage 136 and a second water passage 138. The first water passage 136 is connected to the first bathtub water passage 62, and the second water passage 138 is connected to the second bathtub water passage 70. The first water passage 136 branches into a first discharge passage 136a and a first suction passage 136b. The first discharge passage 136a is connected to a first discharge port 134a provided on the front surface 132a of the bathtub adapter 132. The water discharged from the first discharge port 134a into the bathtub 130 is discharged in front of the wall portion 130a of the bathtub 130, that is, in a direction perpendicular to the wall portion 130a of the bathtub 130. The first discharge passage 136a is provided with a backflow prevention portion 140a that prevents water from flowing from the bathtub 130 toward the first bathtub water passage 62, and a fine bubble generating nozzle 142 that is arranged upstream of the backflow prevention portion 140a (on the first bathtub water passage 62 side). The fine bubble generating nozzle 142 reduces the pressure of the water passing through the fine bubble generating nozzle 142. The first suction passage 136b is connected to a first suction port 134b provided on the front surface 132a of the bathtub adapter 132. The first suction passage 136b is provided with a backflow prevention portion 140b that prevents water from flowing from the first bathtub water passage 62 toward the bathtub 130.

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

(Configuration of the control device 150)
The control device 150 shown in Fig. 1 controls the operation of each component of the heat source unit 10 and the air pressurized dissolution unit 50. The control device 150 is configured to be able to communicate with a remote control 154 that can be operated by a user. The control device 150 includes a memory 152, and is capable of storing various settings input by the user, such as the set temperature and set water volume for the water filling operation, and the set temperature for the reheating operation. The user can use the remote control 154 to instruct the start and end of the water filling operation, reheating operation, and fine bubble generation operation, which will be described later.

(Bath filling operation)
The water filling operation starts when the user instructs the remote control 154 to start the water filling operation. Alternatively, the water filling operation may start when the user sets the start time of the water filling operation on the remote control 154 and the control device 150 determines that the start time of the water filling operation has arrived. When starting the water filling operation, the control device 150 sets the first three-way valve 80 and the second three-way valve 82 to the third communication state and the fifth communication state, respectively (see Figs. 4 and 5). When the water filling operation starts, the control device 150 opens the water filling valve 26 and starts heating by the first heat source unit 12. As a result, as shown in Fig. 4, water adjusted to the set temperature flows from the hot water outlet path 18 through the hot water supply path 24 into the circulation return path 32. The water that flows into the circulation return path 32 branches into a flow toward the upstream side (i.e., the heat source return path 60) and a flow toward the downstream side (i.e., the second heat source unit 14). Water flowing from the circulation return line 32 to the heat source return line 60 flows into the bathtub 130 via the communication passage 66, the first three-way valve 80, the first bathtub water passage 62, and the bathtub adapter 132. Water flowing from the circulation return line 32 to the second heat source unit 14 flows into the bathtub 130 via the circulation forward line 30, the heat source forward line 68, the second three-way valve 82, the second bathtub water passage 70, and the bathtub adapter 132. The control device 150 waits until the accumulated water volume detected by the water volume sensor 28 reaches the set water volume for the bath filling operation. The accumulated water volume here means the accumulated water volume detected by the water volume sensor 28 since the bath filling operation started. When the accumulated water volume reaches the set water volume, the control device 150 closes the bath filling valve 26 and ends the heating of water by the first heat source unit 12. Thereafter, the control device 150 notifies the user via the remote control 154 that the water filling operation has been completed, and ends the water filling operation.

(Reheating operation)
The reheating operation starts when the user instructs the start of the reheating operation on the remote control 154. Alternatively, the reheating operation may start when the control device 150 determines that the temperature detected by the circulation return thermistor 32a does not reach the set temperature after the first heat source unit 12 has finished heating the water during the bath filling operation. When starting the reheating operation, the control device 150 sets the first three-way valve 80 to the third communication state and the second three-way valve 82 to the fifth communication state (see Figures 4 and 5). From this state, the control device 150 drives the bathtub circulation pump 34 and starts heating the water by the second heat source unit 14. As a result, as shown in Figure 5, the water in the bathtub 130 is sent to the second heat source unit 14 via the bathtub adapter 132, the first bathtub water passage 62, the first three-way valve 80, the communication passage 66, the heat source return path 60, and the circulation return path 32. The water heated by the second heat source unit 14 is returned to the bathtub 130 via the circulation outward path 30, the heat source outward 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 circulation return thermistor 32a becomes equal to or higher than the set temperature, the control device 150 stops the bathtub circulation pump 34 and ends the heating of water by the second heat source unit 14. The control device 150 then notifies the user via the remote control 154 that the reheating operation has been completed, and ends the reheating operation.

(Fine bubble generation operation)
The fine bubble generating operation is started when the user instructs the start of the fine bubble generating operation on the remote control 154. In addition, in the hot water device 2 of this embodiment, the fine bubble generating operation is also automatically started after the above-mentioned water filling operation is completed. In other words, the fine bubble generating operation is executed in conjunction with the execution of the water filling operation. When starting the fine bubble generating operation, the control device 150 sets the first three-way valve 80 and the second three-way valve 82 to the third communication state and the fifth communication state, respectively (see Figures 4 and 5). In addition, the control device 150 sets the tank water supply valve 86 to an open state. From this state, the control device 150 executes the process shown in Figure 7.

In S2, the control device 150 drives the tank circulation pump 94. This causes water to circulate between the tank 52 and the tank circulation path 92.

In S4, the control device 150 opens the gas introduction valve 106. This introduces air into the water flowing through the gas introduction mechanism 96 of the tank circulation path 92.

In S6, the control device 150 starts supplying water containing dissolved air from the tank 52 to the bathtub 130. Specifically, as shown in FIG. 6, the control device 150 sets the first three-way valve 80 to the first communication state, sets the second three-way valve 82 to the fourth communication state, and drives the bathtub circulation pump 34, the first pressurizing pump 88, and the second pressurizing pump 90. As a result, water from the bathtub 130 is supplied to the tank 52 via the bathtub adapter 132, the second bathtub water passage 70, the second three-way valve 82, the communication passage 66, the heat source return path 60, the circulation return path 32, the second heat source unit 14, the circulation outward path 30, the heat source outward path 68, and the tank return path 74. At this time, water pressurized by the first pressurizing pump 88 and the second pressurizing pump 90 is supplied from the tank return path 74 to the tank 52. As a result, air is pressurized and dissolved in the water inside the tank 52. The water with the air dissolved under pressure is then supplied to the bathtub 130 from the tank 52 via the tank outflow path 64, the first three-way valve 80, the first bathtub water path 62, and the bathtub adapter 132. At this time, the water with the air dissolved under pressure is depressurized to below atmospheric pressure as it passes through the fine bubble generating nozzle 142 of the first discharge path 136a of the bathtub adapter 132, and is pressurized to atmospheric pressure as it is sprayed into the bathtub 130, generating fine bubbles in the water in the bathtub 130.

In S8, the control device 150 determines whether the water level of the tank 52 falls below the boundary water level based on the presence or absence of an ON signal output from the water level electrode 54. In this embodiment, the amount of air introduced into the gas introduction mechanism 96 when the gas introduction valve 106 is open is greater than the amount of air in the fine bubbles generated in the water of the bathtub 130. Therefore, when the gas introduction valve 106 is open, the amount of air in the tank 52 increases and the water level of the tank 52 falls. If the water level of the tank 52 is equal to or greater than the boundary water level (NO), the process repeats S8. If the water level of the tank 52 falls below the boundary water level (YES), the process proceeds to S10.

In S10, the control device 150 closes the gas introduction valve 106. This stops the introduction of air into the water flowing through the gas introduction mechanism 96 of the tank circulation path 92. With the gas introduction valve 106 closed, no air is supplied to the tank 52, so the amount of air in the tank 52 decreases and the water level in the tank 52 rises. Note that in this embodiment, the tank circulation pump 94 continues to operate even while the gas introduction valve 106 is closed. This promotes the flow of water in the tank 52 and promotes the pressurized dissolution of air into the water in the tank 52.

In S12, the control device 150 starts timing the water level rise time using a built-in timer (not shown).

In S14, the control device 150 determines whether the water level rise time, which began to be timed in S12, exceeds a first predetermined time (e.g., 90 seconds). If the water level rise time is equal to or less than the first predetermined time (NO), the process repeats S14. If the water level rise time exceeds the first predetermined time (YES), the process proceeds to S16.

In S16, the control device 150 ends the measurement of the water level rise time using a built-in timer (not shown).

In S18, the control device 150 opens the gas introduction valve 106. This resumes the introduction of air into the water flowing through the gas introduction mechanism 96 of the tank circulation path 92.

In S20, the control device 150 starts timing the inhalation time using a built-in timer (not shown).

In S22, the control device 150 determines whether the water level of the tank 52 falls below the boundary water level based on the presence or absence of an ON signal output from the water level electrode 54. If the water level of the tank 52 is equal to or higher than the boundary water level (NO), the process repeats S22. If the water level of the tank 52 falls below the boundary water level (YES), the process proceeds to S24.

In S24, the control device 150 closes the gas introduction valve 106. This stops the introduction of air into the water flowing through the gas introduction mechanism 96 of the tank circulation path 92.

In S26, the control device 150 ends the measurement of the inhalation time using a built-in timer (not shown). The control device 150 stores the inhalation time when the measurement is ended in the memory 152.

In S28, the control device 150 determines whether the intake time stored in the memory 152 in S26 exceeds a predetermined upper intake time limit (e.g., 120 seconds). If the intake time exceeds the upper intake time limit (YES), the process proceeds to S30. If the intake time is equal to or less than the upper intake time limit (NO), the process proceeds to S32.

In S30, the control device 150 reduces the rotational speed of the first pressure pump 88 and the second pressure pump 90 by a predetermined value (e.g., 10 Hz). This reduces the amount of water supplied to the tank 52 when the first pressure pump 88 and the second pressure pump 90 are subsequently driven. After S30, the process proceeds to S32.

In S32, the control device 150 determines whether the intake time stored in the memory 152 in S26 is below a predetermined lower limit intake time (e.g., 60 seconds). If the intake time is below the lower limit intake time (YES), the process proceeds to S34. If the intake time is equal to or greater than the lower limit intake time (NO), the process proceeds to S36.

In S34, the control device 150 increases the rotation speed of the first pressure pump 88 and the second pressure pump 90 by a predetermined value (e.g., 10 Hz). This increases the amount of water supplied to the tank 52 when the first pressure pump 88 and the second pressure pump 90 are subsequently driven. After S34, the process proceeds to S36.

In S36, the control device 150 determines whether the stop condition for stopping the fine bubble generating operation is satisfied. In this embodiment, the stop condition is that the operation time of the fine bubble generating operation has reached the set time. The operation time of the fine bubble generating operation is the elapsed time since the start of the fine bubble generating operation. In the hot water device 2 of this embodiment, when the fine bubble generating operation is performed independently without being linked to the execution of the water filling operation, the set time is set to, for example, 10 minutes. In contrast, when the fine bubble generating operation is performed in conjunction with the execution of the water filling operation, the set time is set to, for example, 30 minutes. If the stop condition is not satisfied (NO), the process returns to S12. If the stop condition is satisfied (YES), the process proceeds to S38.

In S38, the control device 150 executes a stop process (see FIG. 8) to stop the microbubble generating operation. After S38, the process in FIG. 7 ends.

In the above, it has been described that the control device 150 determines whether or not the stop condition is satisfied in the process of S36. However, the control device 150 can determine whether or not the stop condition is satisfied even during the execution of the processes from S2 to S34. Furthermore, the control device 150 is configured to stop the process being executed and execute the process of S38 (i.e., the stop process) if it determines that the stop condition is satisfied even during the execution of the processes from S2 to S34.

(Stopping process)
8, in S52, if the gas introduction valve 106 is closed, the control device 150 opens the gas introduction valve 106. This restarts the introduction of air into the water flowing through the gas introduction mechanism 96 of the tank circulation path 92.

In S54, the control device 150 determines whether the water level of the tank 52 falls below the boundary water level based on the presence or absence of an ON signal output from the water level electrode 54. If the water level of the tank 52 is equal to or higher than the boundary water level (NO), the process repeats S54. If the water level of the tank 52 falls below the boundary water level (YES), the process proceeds to S56.

In S56, the control device 150 closes the gas introduction valve 106. This stops the introduction of air into the water flowing through the gas introduction mechanism 96 of the tank circulation path 92.

In S58, the control device 150 starts timing the water level rise time using a built-in timer (not shown).

In S60, the control device 150 determines whether the water level rise time, which began to be timed in S58, exceeds a second predetermined time (e.g., 180 seconds), which is longer than the first predetermined time. If the water level rise time is equal to or shorter than the second predetermined time (NO), the process repeats S60. If the water level rise time exceeds the second predetermined time (YES), the process proceeds to S62.

In S62, the control device 150 ends the measurement of the water level rise time using a built-in timer (not shown).

In S64, the control device 150 stops the bathtub circulation pump 34, the first pressure pump 88, and the second pressure pump 90, and ends the supply of air-dissolved water from the tank 52 to the bathtub 130.

In S66, the control device 150 stops the tank circulation pump 94. This ends the circulation of water between the tank 52 and the tank circulation path 92. After S66, the processing in FIG. 8 ends.

In this way, in the stop process, the control device 150 can stop the fine bubble generating operation with the water level electrode 54 submerged in water. At this time, since the water level in the tank 52 at the time the process in FIG. 8 is completed is higher than the water level in the tank 52 at the time the gas introduction valve 106 is opened in S18 in FIG. 7, the water level electrode 54 is submerged in water up to a part above the part that is submerged in water during normal operation. This makes it possible to appropriately suppress the occurrence of slime on the water level electrode 54.

Example 2
The hot water device 2 of this embodiment has a configuration substantially similar to that of the hot water device 2 of embodiment 1. In the hot water device 2 of this embodiment, when performing the fine bubble generating operation, the control device 150 performs the process shown in Fig. 9 instead of the process shown in Fig. 7. The following describes the process shown in Fig. 9 in terms of differences from the process shown in Fig. 7.

In the process shown in FIG. 9, if the intake time stored in memory 152 in S26 exceeds the upper intake time limit (YES in S28), the process proceeds to S70. In S70, the control device 150 increases the rotation speed of the tank circulation pump 94 by a predetermined value (e.g., 10 Hz). This increases the amount of air introduced by the gas introduction mechanism 96 when the tank circulation pump 94 is subsequently driven with the gas introduction valve 106 open. After S70, the process proceeds to S32.

On the other hand, if the intake time stored in memory 152 in S26 falls below the lower limit intake time (YES in S32), processing proceeds to S72. In S72, the control device 150 reduces the rotation speed of the tank circulation pump 94 by a predetermined value (e.g., 10 Hz). As a result, when the tank circulation pump 94 is subsequently driven with the gas introduction valve 106 open, the amount of air introduced by the gas introduction mechanism 96 decreases. After S72, processing proceeds to S36.

In addition, in S70 of the process shown in FIG. 9, the control device 150 may be configured to increase the rotation speed of the tank circulation pump 94 when the tank circulation pump 94 is subsequently driven with the gas introduction valve 106 open, but not to increase the rotation speed of the tank circulation pump 94 when the tank circulation pump 94 is subsequently driven with the gas introduction valve 106 closed. Similarly, in S72 of the process shown in FIG. 9, the control device 150 may be configured to reduce the rotation speed of the tank circulation pump 94 when the tank circulation pump 94 is subsequently driven with the gas introduction valve 106 open, but not to reduce the rotation speed of the tank circulation pump 94 when the tank circulation pump 94 is subsequently driven with the gas introduction valve 106 closed.

Example 3
The hot water device 2 of this embodiment has a configuration substantially similar to that of the hot water device 2 of Example 1. In the hot water device 2 of this embodiment, when performing the fine bubble generating operation, the control device 150 executes the process shown in Fig. 10 instead of executing the process shown in Fig. 7 .

In S82, the control device 150 drives the tank circulation pump 94. This causes water to circulate between the tank 52 and the tank circulation path 92.

In S84, the control device 150 starts supplying the air-dissolved water from the tank 52 to the bathtub 130. At this time, the control device 150 performs the same process as S8 in FIG. 7.

In S86, the control device 150 determines whether the water level of the tank 52 is equal to or higher than the boundary water level based on the presence or absence of an ON signal output from the water level electrode 54. If the water level of the tank 52 is below the boundary water level (NO), the process repeats S86. If the water level of the tank 52 is equal to or higher than the boundary water level (YES), the process proceeds to S88.

In S88, the control device 150 opens the gas introduction valve 106. This starts the introduction of air into the water flowing through the gas introduction mechanism 96 of the tank circulation path 92.

In S90, the control device 150 starts timing the water level drop time using a built-in timer (not shown).

In S92, the control device 150 determines whether the water level drop time, which began to be measured in S90, exceeds a third predetermined time (e.g., 90 seconds). If the water level drop time is equal to or less than the third predetermined time (NO), the process repeats S92. If the water level drop time exceeds the third predetermined time (YES), the process proceeds to S94.

In S94, the control device 150 ends the measurement of the water level drop time using a built-in timer (not shown).

In S96, the control device 150 closes the gas introduction valve 106. This stops the introduction of air into the water flowing through the gas introduction mechanism 96 of the tank circulation path 92.

In S98, the control device 150 starts timing the exhaust time using a built-in timer (not shown).

In S100, the control device 150 determines whether the water level of the tank 52 is equal to or higher than the boundary water level based on the presence or absence of an ON signal output from the water level electrode 54. If the water level of the tank 52 is below the boundary water level (NO), the process repeats S100. If the water level of the tank 52 is equal to or higher than the boundary water level (YES), the process proceeds to S102.

In S102, the control device 150 opens the gas introduction valve 106. This resumes the introduction of air into the water flowing through the gas introduction mechanism 96 of the tank circulation path 92.

In S104, the control device 150 ends the measurement of the exhaust time using a built-in timer (not shown). The control device 150 stores the exhaust time when the measurement is ended in the memory 152.

In S106, the control device 150 determines whether the exhaust time stored in the memory 152 in S104 exceeds a predetermined upper exhaust time limit (e.g., 120 seconds). If the exhaust time exceeds the upper exhaust time limit (YES), the process proceeds to S108. If the exhaust time is equal to or less than the upper exhaust time limit (NO), the process proceeds to S110.

In S108, the control device 150 increases the rotation speed of the first pressurizing pump 88 and the second pressurizing pump 90 by a predetermined value (e.g., 10 Hz). This increases the amount of water supplied to the tank 52 when the first pressurizing pump 88 and the second pressurizing pump 90 are subsequently driven. After S108, the process proceeds to S110.

In S110, the control device 150 determines whether the exhaust time stored in the memory 152 in S104 is below a predetermined lower limit exhaust time (e.g., 60 seconds). If the exhaust time is below the lower limit exhaust time (YES), the process proceeds to S112. If the exhaust time is equal to or greater than the lower limit exhaust time (NO), the process proceeds to S114.

In S112, the control device 150 reduces the rotational speeds of the first pressure pump 88 and the second pressure pump 90 by a predetermined value (e.g., 10 Hz). This reduces the amount of water supplied to the tank 52 when the first pressure pump 88 and the second pressure pump 90 are subsequently driven. After S112, the process proceeds to S114.

In S114, the control device 150 determines whether the stop condition for stopping the microbubble generating operation is satisfied. If the stop condition is not satisfied (NO), the process returns to S90. If the stop condition is satisfied (YES), the process proceeds to S116.

In S116, the control device 150 executes a stop process (see FIG. 8) to stop the microbubble generating operation. After S116, the process in FIG. 10 ends.

In the above, it has been described that the control device 150 determines whether or not the stop condition is satisfied in the process of S114. However, the control device 150 can determine whether or not the stop condition is satisfied even during the execution of the processes from S82 to S112. Furthermore, the control device 150 is configured to stop the process being executed and execute the process of S116 (i.e., the stop process) if it determines that the stop condition is satisfied even during the execution of the processes from S82 to S112.

10, the control device 150 may be configured to reduce the rotation speed of the tank circulation pump 94 by a predetermined value (e.g., 10 Hz) instead of increasing the rotation speed of the first pressurizing pump 88 and the second pressurizing pump 90 by a predetermined value. As a result, when the tank circulation pump 94 is subsequently driven with the gas introduction valve 106 open, the amount of air introduced by the gas introduction mechanism 96 decreases. Similarly, in S112 of the process shown in FIG. 10, the control device 150 may be configured to increase the rotation speed of the tank circulation pump 94 by a predetermined value (e.g., 10 Hz) instead of reducing the rotation speed of the first pressurizing pump 88 and the second pressurizing pump 90 by a predetermined value. As a result, when the tank circulation pump 94 is subsequently driven with the gas introduction valve 106 open, the amount of air introduced by the gas introduction mechanism 96 increases.

(Modification)
In the above-described hot water device 2, air is introduced into the tank 52, but instead of air, gas such as carbon dioxide gas, hydrogen, oxygen, etc. may be introduced into the tank 52. In this case, a gas-filled tank (not shown) filled with gas may be connected to the gas inlet 104a of the gas introduction path 104.

In the above-mentioned hot water device 2, during the bath filling operation, a set amount of water is stored in the bathtub 130 based on the accumulated water volume detected by the water volume sensor 28. In another embodiment, the hot water device 2 may be configured to be provided with a water level sensor capable of detecting the water level of the bathtub 130, for example, and to store water at the set water level in the bathtub 130 based on the water level of the bathtub 130 detected by the water level sensor during the bath filling operation.

In the above-mentioned hot water device 2, the heat source unit 10 is connected to the faucet 250, and the air pressure dissolution unit 50 is connected to the bathtub 130. In another embodiment, the heat source unit 10 may be connected to another heat utilization location, and the air pressure dissolution unit 50 may be connected to another liquid tank.

In the above-mentioned hot water device 2, the gas introduction mechanism 96 is disposed upstream of the tank circulation pump 94 in the tank circulation path 92. In another embodiment, the gas introduction mechanism 96 may be disposed downstream of the tank circulation pump 94 in the tank circulation path 92.

In the hot water device 2 described above, the downstream end of the tank circulation path 92 is connected to the tank return path 74 downstream of the second pressure pump 90. In another embodiment, the downstream end of the tank circulation path 92 does not need to be connected to the tank return path 74, and may be provided separately from the tank return path 74 for the tank 52.

In the above-mentioned hot water device 2, only one water level electrode, the water level electrode 54, is provided to detect the water level in the tank 52. In another embodiment, multiple water level electrodes may be provided to detect the water level in the tank 52.

In the hot water device 2 described above, the user may be able to switch via the remote control 154 whether or not to execute the fine bubble generating operation in conjunction with the execution of the hot water filling operation.

In the above hot water device 2, when the intake time exceeds the upper intake time limit (YES in S28 in FIG. 7 or FIG. 9), the control device 150 is configured to reduce the rotation speed of the first pressurizing pump 88 and the second pressurizing pump 90 by a predetermined value (S30 in FIG. 7) or increase the rotation speed of the tank circulation pump 94 by a predetermined value (S70 in FIG. 9). In another embodiment, when the intake time exceeds the upper intake time limit, the control device 150 may be configured to reduce the rotation speed of the first pressurizing pump 88 and the second pressurizing pump 90 by a predetermined value and increase the rotation speed of the tank circulation pump 94 by a predetermined value. In yet another embodiment, when the intake time exceeds the upper intake time limit, the control device 150 may be configured to shorten the first predetermined time in S14 in FIG. 7 or FIG. 9 instead of correcting the rotation speeds of the first pressurizing pump 88, the second pressurizing pump 90, and the tank circulation pump 94. This reduces the time it takes to raise the water level in the tank 52 (the time it takes to repeatedly execute S14) when it is detected that the water level in the tank 52 has subsequently fallen below the boundary water level and the water level in the tank 52 is raised (YES in S8).

In the above hot water device 2, when the intake time is below the lower limit intake time (YES in S32 in FIG. 7 or FIG. 9), the control device 150 is configured to increase the rotation speed of the first pressurizing pump 88 and the second pressurizing pump 90 by a predetermined value (S34 in FIG. 7) or reduce the rotation speed of the tank circulation pump 94 by a predetermined value (S72 in FIG. 9). In another embodiment, when the intake time is below the lower limit intake time, the control device 150 may be configured to increase the rotation speed of the first pressurizing pump 88 and the second pressurizing pump 90 by a predetermined value and reduce the rotation speed of the tank circulation pump 94 by a predetermined value. In yet another embodiment, when the intake time is below the lower limit intake time, the control device 150 may be configured to extend the first predetermined time in S14 in FIG. 7 or FIG. 9 instead of correcting the rotation speeds of the first pressurizing pump 88, the second pressurizing pump 90, and the tank circulation pump 94. As a result, if it is subsequently detected that the water level in the tank 52 falls below the boundary water level and the water level in the tank 52 is raised (YES in S8), the time for which the water level in the tank 52 is raised (the time for which S14 is repeatedly executed) is extended.

In the hot water device 2 described above, the stop condition for stopping the fine bubble generating operation is that the operating time of the fine bubble generating operation has reached a set time. In another embodiment, the stop condition does not have to be that the operating time of the fine bubble generating operation has reached a set time. For example, the stop condition may be that the user issues an instruction to end the fine bubble generating operation via the remote control 154.

The length of the water level electrode 54 in the above-mentioned hot water device 2 may be changed as appropriate. In other words, the boundary water level in the above-mentioned hot water device 2 may be changed as appropriate.

In the above hot water device 2, the first specified time, the second specified time, the third specified time, the upper limit intake time, the lower limit intake time, the correction value for the rotation speed of the first pressure pump 88 and the second pressure pump 90, the correction value for the rotation speed of the tank circulation pump 94, and the set time for stopping the fine bubble operation may each be changed as appropriate.

(Correspondence)
As described above, in one or more embodiments, the hot water device 2 (an example of a fine bubble generating device) includes the tank 52 for pressurizing and dissolving air (an example of a gas) in water (an example of a liquid), the tank return path 74 (an example of a tank supply path) for supplying water to the tank 52, the first pressure pump 88 and the second pressure pump 90 (an example of a pressure pump) provided in the tank return path 74, the tank forward path 64 for discharging the water in which the air has been pressurized and dissolved from the tank 52 to the bathtub 130 (an example of a liquid tank), the first bathtub water path 62, the bathtub adaptor 132 (an example of a tank discharge path), and the bathtub adaptor 132. The apparatus includes a fine bubble generating nozzle 142 that generates fine bubbles by reducing the pressure of the water, a tank circulation path 92 that is provided separately from the tank outflow path 64, the first bath water path 62, and the bath adapter 132 and sends water from an outlet 92a connected to the tank 52 to a water supply port 74a (an example of an inlet) connected to the tank 52, a tank circulation pump 94 provided in the tank circulation path 92, a gas introduction mechanism 96 provided in the tank circulation path 92, a water level electrode 54 (an example of a liquid level electrode) that can detect whether the water level of the tank 52 is equal to or higher than a boundary water level (an example of a predetermined liquid level), and a control device 150. The gas introduction mechanism 96 includes a Venturi tube 102 (an example of a pressure reducing section) that reduces the pressure of the water and passes it through, a gas introduction port 104a that introduces air by the negative pressure of the water in the Venturi tube 102, and a gas introduction valve 106 that opens and closes the gas introduction port 104a. The control device 150 can execute a fine bubble generating operation, in which water is pressurized and supplied from the tank return line 74 to the tank 52 by driving the first pressure pump 88 and the second pressure pump 90, and water in which air is pressurized and dissolved is supplied from the tank 52 to the bathtub 130 via the tank forward line 64, the first bathtub water line 62, and the bathtub adapter 132. The control device 150 supplies air introduced from the gas inlet 104a to the tank 52 by driving the tank circulation pump 94 to circulate the water in the tank 52 through the tank circulation line 92, and controls the opening and closing operation of the gas introduction valve 106 based on the presence or absence of an ON signal output from the water level electrode 54 (an example of information related to whether the liquid level in the tank detected by the liquid level electrode is equal to or higher than a predetermined liquid level).

In one or more embodiments, the hot water device 2 (an example of a fine bubble generating device) includes a tank 52 that pressurizes and dissolves air (an example of a gas) in water (an example of a liquid), a tank return line 74 (an example of a tank supply line) that supplies water to the tank 52, a first pressure pump 88 and a second pressure pump 90 (an example of a pressure pump) provided in the tank return line 74, a tank forward line 64 that discharges water in which air has been pressurized and dissolved from the tank 52 to a bathtub 130 (an example of a liquid tank), a first bathtub water line 62, a bathtub adapter 132 (an example of a tank discharge line), and a bathtub adapter 132 that is provided with a tank outlet line 64 that discharges water in which air has been pressurized and dissolved from the tank 52 to a bathtub 130 (an example of a liquid tank). The device includes a fine bubble generating nozzle 142 that generates fine bubbles by applying pressure to the tank, a tank circulation path 92 that is provided separately from the tank outflow path 64, the first bathtub water path 62, and the bathtub adapter 132 and sends water from an outlet 92a connected to the tank 52 to a water supply port 74a (an example of an inlet) connected to the tank 52, a tank circulation pump 94 provided in the tank circulation path 92, a gas introduction mechanism 96 provided in the tank circulation path 92, a single water level electrode 54 (an example of a liquid level electrode) that can detect whether the water level of the tank 52 is equal to or higher than a boundary water level (an example of a predetermined liquid level), and a control device 150. The gas introduction mechanism 96 includes a Venturi tube 102 (an example of a pressure reducing section) that reduces the pressure of the water and passes it through, a gas introduction port 104a that introduces air by the negative pressure of the water in the Venturi tube 102, and a gas introduction valve 106 that opens and closes the gas introduction port 104a. The control device 150 can perform a fine bubble generating operation by driving the first pressure pump 88 and the second pressure pump 90 to pressurize and supply water from the tank return line 74 to the tank 52, and supplying water with air pressurized and dissolved therein from the tank 52 to the bathtub 130 via the tank forward line 64, the first bathtub water line 62, and the bathtub adapter 132. The control device 150 drives the tank circulation pump 94 to circulate the water in the tank 52 through the tank circulation line 92, thereby supplying air introduced from the gas inlet 104a to the tank 52, and controlling the opening and closing of the gas introduction valve 106 based on the presence or absence of an ON signal output from a single water level electrode 54 (an example of information related to whether the liquid level in the tank detected by the liquid level electrode is equal to or higher than a predetermined liquid level).

According to the above configuration, the control device 150 is configured to control the opening and closing operation of the gas introduction valve 106 based on the presence or absence of an ON signal output from one water level electrode 54. This reduces the amount of information related to the water level of the tank 52, and ensures rapid decision-making processing related to the opening and closing of the gas introduction valve 106.

In one or more embodiments, when the control device 150 detects via the water level electrode 54 that the water level in the tank 52 is lower than the boundary water level while the gas introduction valve 106 is open during the execution of the fine bubble generating operation, the control device 150 closes the gas introduction valve 106, keeps the gas introduction valve 106 closed until a first predetermined time has elapsed since the gas introduction valve 106 was closed, and opens the gas introduction valve 106 after the first predetermined time has elapsed.

In the hot water device 2, water droplets scattered from the water surface of the tank 52 may adhere to the water level electrode 54, which may cause slime to form on the water level electrode 54. If slime forms on the water level electrode 54, there is a risk of erroneous detection of the water level of the tank 52. For example, if the hot water device 2 has a lower water level electrode and an upper water level electrode, and the control device 150 controls the opening and closing operation of the gas introduction valve 106 so that the water level of the tank 52 transitions between the lower water level and the upper water level, the upper water level electrode is hardly immersed in water. For this reason, the occurrence of slime cannot be suppressed on the upper water level electrode, and there is a risk of erroneous detection of the water level of the tank 52. According to the above configuration, the occurrence of slime on the water level electrode 54 can be suppressed by frequently immersing the water level electrode 54 in water during the execution of the fine bubble generation operation. Therefore, erroneous detection of the water level of the tank 52 can be suppressed.

In one or more embodiments, the control device 150, during the execution of the fine bubble generating operation, determines the elapsed time from when the gas introduction valve 106, which is in a closed state, is opened until the water level electrode 54 detects that the water level in the tank 52 is lower than the boundary water level and closes the gas introduction valve 106 as the intake time, and if the intake time exceeds the upper intake time limit, reduces the rotation speed of the first pressure pump 88 and the second pressure pump 90 when driving the first pressure pump 88 and the second pressure pump 90 thereafter.

If the intake time is too long, it is assumed that the amount of water supplied to the tank 52 is too large or the amount of air introduced by the gas introduction mechanism 96 is too small. In addition, the higher the rotation speed of the first pressurizing pump 88 and the second pressurizing pump 90, the more water is supplied to the tank 52, and the lower the rotation speed of the first pressurizing pump 88 and the second pressurizing pump 90, the less water is supplied to the tank 52. According to the above configuration, when the intake time exceeds the upper intake time limit, i.e., when the intake time is too long, the rotation speed of the first pressurizing pump 88 and the second pressurizing pump 90 is reduced to reduce the amount of water supplied to the tank 52 and shorten the intake time.

In one or more embodiments, the control device 150, during the execution of the fine bubble generating operation, determines the elapsed time from when the gas introduction valve 106, which is in a closed state, is opened until the water level electrode 54 detects that the water level in the tank 52 is lower than the boundary water level and closes the gas introduction valve 106 as the intake time, and if the intake time falls below the lower limit intake time, increases the rotation speed of the first pressure pump 88 and the second pressure pump 90 when driving them thereafter.

If the intake time is too short, it is assumed that the amount of water supplied to the tank 52 is too small, or the amount of air introduced by the gas introduction mechanism 96 is too large. With the above configuration, if the intake time falls below the lower limit intake time, i.e., if the intake time is too short, the rotation speed of the first pressure pump 88 and the second pressure pump 90 can be increased to increase the amount of water supplied to the tank 52 and extend the intake time.

In one or more embodiments, the control device 150, during the execution of the fine bubble generating operation, determines the elapsed time from when the gas introduction valve 106, which is in a closed state, is opened until the water level electrode 54 detects that the water level in the tank 52 is lower than the boundary water level and closes the gas introduction valve 106 as the intake time, and if the intake time exceeds the upper intake time limit, increases the rotation speed of the tank circulation pump 94 when driving the tank circulation pump 94 with the gas introduction valve 106 open thereafter.

If the intake time is too long, it is assumed that either too much water is being supplied to the tank 52 or too little air is being introduced by the gas introduction mechanism 96. Furthermore, when the gas introduction valve 106 is open, the higher the rotation speed of the tank circulation pump 94, the greater the amount of air being introduced by the gas introduction mechanism 96, and the lower the rotation speed of the tank circulation pump 94, the less the amount of air being introduced by the gas introduction mechanism 96. With the above configuration, if the intake time exceeds the upper intake time limit, i.e., if the intake time is too long, the rotation speed of the tank circulation pump 94 can be increased to increase the amount of air being introduced by the gas introduction mechanism 96 and shorten the intake time.

In one or more embodiments, the control device 150, during execution of the fine bubble generating operation, determines the elapsed time from when the gas introduction valve 106, which is in a closed state, is opened until the water level electrode 54 detects that the water level in the tank 52 is lower than the boundary water level and closes the gas introduction valve 106 as the intake time, and if the intake time falls below the lower limit intake time, reduces the rotation speed of the tank circulation pump 94 when the tank circulation pump 94 is subsequently driven with the gas introduction valve 106 open.

If the intake time is too short, it is assumed that either the amount of water supplied to the tank 52 is too small or the amount of air introduced by the gas introduction mechanism 96 is too large. With the above configuration, if the intake time falls below the lower limit intake time, i.e., if the intake time is too short, the rotation speed of the tank circulation pump 94 is reduced to reduce the amount of air introduced by the gas introduction mechanism 96 and extend the intake time.

In one or more embodiments, the control device 150 is capable of determining whether or not a stop condition for stopping the fine bubble generating operation is satisfied during the execution of the fine bubble generating operation, and executes a stop process for stopping the fine bubble generating operation when the stop condition is satisfied. When the stop process is executed, the control device 150 opens the gas introduction valve 106 while driving the first pressurizing pump 88, the second pressurizing pump 90, and the tank circulation pump 94, and when the water level electrode 54 detects that the water level of the tank 52 is lower than the boundary water level while the gas introduction valve 106 is open, closes the gas introduction valve 106, and maintains the gas introduction valve 106 closed until a second predetermined time, which is longer than the first predetermined time, has elapsed since the gas introduction valve 106 was closed, and after the second predetermined time has elapsed, stops the first pressurizing pump 88, the second pressurizing pump 90, and the tank circulation pump 94 to stop the fine bubble generating operation.

According to the above configuration, the microbubble generating operation can be stopped while the water level electrode 54 is submerged in water. This can suppress the occurrence of slime on the water level electrode 54 and suppress erroneous detection of the water level of the tank 52. Furthermore, according to the above configuration, when the microbubble generating operation is stopped, the water level electrode 54 is submerged in water up to a portion above the portion that is submerged in water during normal operation. Therefore, the occurrence of slime on the water level electrode 54 can be more appropriately suppressed.

In one or more embodiments, when the control device 150 detects via the water level electrode 54 that the water level of the tank 52 is equal to or higher than the boundary water level while the gas introduction valve 106 is closed during the execution of the fine bubble generating operation, the control device 150 opens the gas introduction valve 106, keeps the gas introduction valve 106 open until a third predetermined time has elapsed since the gas introduction valve 106 was opened, and closes the gas introduction valve 106 after the third predetermined time has elapsed.

For example, if the hot water device 2 is equipped with a lower water level electrode and an upper water level electrode, and the control device 150 controls the opening and closing operation of the gas introduction valve 106 so that the water level of the tank 52 fluctuates between the lower water level and the upper water level, the length of the lower water level electrode needs to be relatively long. In this case, this may lead to an increase in the weight of the entire hot water device 2. With the above configuration, the length of the water level electrode 54 can be made relatively short. This allows the entire hot water device 2 to be made lighter.

In one or more embodiments, the liquid is water. The liquid reservoir is a bathtub 130 in which a user bathes.

With the above configuration, in the hot water heater 2 that generates fine bubbles in the water of the bathtub 130 that the user uses for bathing, the amount of information related to the water level of the tank 52 can be reduced, and rapid decision-making processing related to opening and closing the gas introduction valve 106 can be ensured.

Although the embodiments have been described in detail above, they are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples given above. The technical elements described in this specification or drawings are technically useful either alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology illustrated in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of these objectives is itself technically useful.

2: Hot water device 10: Heat source unit 12: First heat source unit 14: Second heat source unit 16: Water supply line 18: Hot water outlet line 18a: Outlet water temperature thermistor 20: Bypass line 22: Bypass servo 24: Hot water supply line 26: Valve 28: Water volume sensor 30: Circulation forward line 30a: Circulation forward line thermistor 32: Circulation return line 32a: Circulation return line thermistor 34: Bathtub circulation pump 36: Water flow switch 50: Air pressure dissolving unit 52: Tank 54: Water level electrode 60: Heat source return line 62: First bathtub water line 64: Tank forward line 66: Communication passage 68: Heat source forward line 70: Second bathtub water line 74: Tank return line 74a: Water supply port 80: First three-way valve 82: Second three-way valve 84 : check valve 86 : tank water supply valve 88 : first pressure pump 90 : second pressure pump 92 : tank circulation path 92a : outlet 94 : tank circulation pump 96 : gas introduction mechanism 98 : water inlet pipe 100 : water outlet pipe 102 : venturi tube 104 : gas introduction path 104a : gas introduction port 106 : gas introduction valve 130 : bathtub 130a : wall 132 : bathtub adapter 132a : front surface 132b : bottom surface 134a : first outlet port 134b : first suction port 134c : second suction port 134d : second outlet port 136 : first water passage 136a : first outlet passage 136b : first suction passage 138 : second water passage 138a : second outlet passage 138b : Second suction passage 140a, 140b, 140c, 140d : Non-return section 142 : Micro-bubble generating nozzle 150 : Control device 152 : Memory 154 : Remote control 200 : Water supply source 250 : Faucet

Claims (10)

A tank for dissolving gas under pressure in liquid;
a tank supply line for supplying the liquid to the tank;
a pressure pump provided in the tank supply line;
a tank discharge passage for discharging the liquid in which the gas is pressurized and dissolved from the tank to a liquid tank;
a fine bubble generating nozzle provided in the tank discharge path for generating fine bubbles by reducing the pressure of the liquid in which the gas is pressurized and dissolved;
a tank circulation path that is provided separately from the tank discharge path and that sends 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;
a liquid level electrode capable of detecting whether the liquid level in the tank is equal to or higher than a predetermined liquid level;
A control device,
The gas introduction mechanism includes:
a pressure reducing section for reducing the pressure of the liquid and passing the liquid therethrough;
a gas inlet port that introduces the gas by negative pressure of the liquid in the pressure reducing section;
a gas introduction valve for opening and closing the gas introduction port,
The control device includes:
a fine bubble generating operation can be performed in which the pressurizing pump is driven to pressurize and supply the liquid from the tank supply path to the tank, and the liquid in which the gas is pressurized and dissolved is supplied from the tank to the liquid tank via the tank discharge path,
During the execution of the fine bubble generating operation,
The tank circulation pump is driven to circulate the liquid in the tank through the tank circulation path, thereby supplying the gas introduced through the gas inlet to the tank;
a control unit for controlling an opening and closing operation of the gas introduction valve based on information regarding whether the liquid level in the tank detected by the liquid level electrode is equal to or higher than a predetermined liquid level. The control device includes:
During the execution of the fine bubble generating operation,
when the liquid level electrode detects that the liquid level in the tank is lower than the predetermined liquid level while the gas introduction valve is open, the gas introduction valve is closed;
The gas introduction valve is maintained in a closed state until a first predetermined time has elapsed since the gas introduction valve was closed;
2. The fine bubble generating device according to claim 1, wherein the gas introduction valve is opened after the first predetermined time has elapsed. The control device includes:
During the execution of the fine bubble generating operation,
specifying an intake time as an elapsed time from when the gas introduction valve is opened from the closed state until when the liquid level electrode detects that the liquid level in the tank is lower than the predetermined liquid level and the gas introduction valve is closed;
3. The fine-bubble generating device according to claim 2, wherein, when the intake time exceeds an upper intake time limit, the number of revolutions of the pressure pump when the pressure pump is subsequently driven is reduced. The control device includes:
During the execution of the fine bubble generating operation,
specifying an intake time as an elapsed time from when the gas introduction valve is opened from the closed state until when the liquid level electrode detects that the liquid level in the tank is lower than the predetermined liquid level and the gas introduction valve is closed;
4. The fine-bubble generating device according to claim 2, wherein, when the intake time falls below a lower limit intake time, the rotational speed of the pressure pump is increased when the pressure pump is subsequently driven. The control device includes:
During the execution of the fine bubble generating operation,
specifying an intake time as an elapsed time from when the gas introduction valve is opened from the closed state until when the liquid level electrode detects that the liquid level in the tank is lower than the predetermined liquid level and the gas introduction valve is closed;
5. The fine-bubble generating device according to claim 2, wherein, when the intake time exceeds an upper limit intake time, the rotation speed of the tank circulating pump is increased when the tank circulating pump is driven thereafter with the gas introduction valve open. The control device includes:
During the execution of the fine bubble generating operation,
specifying an intake time as an elapsed time from when the gas introduction valve is opened from the closed state until when the liquid level electrode detects that the liquid level in the tank is lower than the predetermined liquid level and the gas introduction valve is closed;
6. The fine-bubble generating device according to claim 2, wherein, when the intake time falls below a lower limit intake time, the rotation speed of the tank circulating pump is reduced when the tank circulating pump is subsequently driven with the gas introduction valve open. The control device includes:
During the execution of the fine bubble generating operation,
It is possible to determine whether a stop condition for stopping the fine bubble generating operation is satisfied,
When the stop condition is satisfied, a stop process is executed to stop the fine bubble generating operation.
When the stop process is executed,
opening the gas introduction valve while driving the pressure pump and the tank circulation pump;
when the liquid level electrode detects that the liquid level in the tank is lower than the predetermined liquid level while the gas introduction valve is open, the gas introduction valve is closed;
The gas introduction valve is maintained in a closed state until a second predetermined time, which is longer than the first predetermined time, has elapsed since the gas introduction valve was closed;
7. The fine-bubble generating device according to claim 2, wherein the pressurizing pump and the tank circulating pump are stopped to stop the fine-bubble generating operation after the second predetermined time has elapsed. The control device includes:
During the execution of the fine bubble generating operation,
when the liquid level electrode detects that the liquid level in the tank is equal to or higher than the predetermined liquid level while the gas introduction valve is closed, the gas introduction valve is opened;
The gas introduction valve is maintained in an open state until a third predetermined time has elapsed since the gas introduction valve was opened,
2. The fine bubble generating device according to claim 1, wherein the gas introduction valve is closed after the third predetermined time has elapsed. A tank for dissolving gas under pressure in liquid;
a tank supply line for supplying the liquid to the tank;
a pressure pump provided in the tank supply line;
a tank discharge passage for discharging the liquid in which the gas is pressurized and dissolved from the tank to a liquid tank;
a fine bubble generating nozzle provided in the tank discharge path for generating fine bubbles by reducing the pressure of the liquid in which the gas is pressurized and dissolved;
a tank circulation path that is provided separately from the tank discharge path and that sends 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;
a single level electrode capable of detecting whether the liquid level in the tank is equal to or higher than a predetermined liquid level;
A control device is provided.
The gas introduction mechanism includes:
a pressure reducing section for reducing the pressure of the liquid and passing the liquid therethrough;
a gas inlet port that introduces the gas by negative pressure of the liquid in the pressure reducing section;
a gas introduction valve for opening and closing the gas introduction port,
The control device includes:
a fine bubble generating operation can be performed in which the pressurizing pump is driven to pressurize and supply the liquid from the tank supply path to the tank, and the liquid in which the gas is pressurized and dissolved is supplied from the tank to the liquid tank via the tank discharge path,
During the execution of the fine bubble generating operation,
The tank circulation pump is driven to circulate the liquid in the tank through the tank circulation path, thereby supplying the gas introduced through the gas inlet to the tank;
a control unit for controlling an opening and closing operation of the gas introduction valve based on information regarding whether the liquid level in the tank detected by the single liquid level electrode is equal to or higher than a predetermined liquid level. the liquid is water,
The fine bubble generating device according to claim 1 , wherein the liquid tank is a bathtub used by a user for bathing.