JPH07163630A - Fine bubble generating device - Google Patents

Abstract

PURPOSE:To supply stable fine bubbles free from the ingress of large bubbles even at the re-start of a pump unit. CONSTITUTION:A water line 4 for connecting a hot water supply port 2 and a jet hole 3 in a bathtub 1 is provided with an air supply section 6 having a solenoid valve 5, a pump 7 and an accumulator respectively in order from the port 2. An operation start signal from an operation switch 9 capses the solenoid valve 5 to open and at the same time, actuates the pump 7. Fine bubbles are delivered to the bathtub 1 on the operation of the pump 7. Also, a control section 11 is formed in such state as equipped with a delay means 10 for closing the solenoid valve 5 with an operation stop signal from the switch 9, and stopping the pump 7 in the preset time after the closure of the valve 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fine bubble generator for discharging fine bubbles into a bath.

[0002]

2. Description of the Related Art Conventionally, a fine bubble generator as shown in FIG. 7 has been known. This conventional micro-bubble generating device forms a water channel 4 connecting a hot water inlet 2 and an injection port 3 provided in a bathtub 1, and an air supply unit having a solenoid valve 5 in order from the hot water inlet 2 side. 6, a pump 7, and an accumulator 8 are arranged. Reference numeral 16 in FIG. 7 denotes a motor for operating the pump 7, and a part of the pipes forming the water channel 4, the pump 7, the motor 16, the accumulator 8,
The control unit 11 and the like are incorporated in the pump unit A. Reference numeral 9 in the figure denotes an operation switch, which is a motor 1 for operating the pump 7 in response to an operation start signal from the operation switch 9.
6 is turned on, the solenoid valve 5 is opened at the same time, and an operation stop signal from the operation switch 9 turns off the motor 16 and at the same time closes the solenoid valve 5.

FIG. 8 shows a time chart of a conventional example. As shown in this time chart, when the operation switch 9 is operated to be turned on and a start signal is sent to the control section 11, the control section 11 causes A signal for driving the motor 16 for operating the pump and a signal for opening the solenoid valve 5 of the air supply unit 6 are sent, the motor 16 is turned on to operate the pump 7, and at the same time the solenoid valve 5 is operated. Opens and bathtub 1
The pump 7 inhales the bath water and the air in the atmosphere. The bath water and air inhaled by the pump 7 are pump 7
It is pressurized to about 6 kg / cm ² inside, and the air is pressure-dissolved in the bath water and sent to the injection port 3 side. On the way, the accumulator 8 is rectified to separate the pressurized dissolved water of air from the surplus air, and the surplus air is exhausted to the atmosphere from the exhaust unit 14 to convey only the pressurized dissolved water to the injection port 3. Will be done. Here, the exhaust part 14 may partially discharge water during exhaust. The pressurized dissolved water sent to the injection port 3 through the accumulator 8 decompresses the pressurized dissolved water of air at the injection port 3, and further bundles about 10 wire meshes of about 100 mesh built in the injection port 3. By passing through the net cartridge, fine air bubbles having a diameter of about 10 μ are generated and are discharged into the bath 1. Then, by pressing the operation switch 9 again and turning it on again, a stop signal is sent to the control unit 11, the motor 16 is turned off, the operation of the pump 7 is stopped, and the solenoid valve 5 is closed at the same time, so that the bath water and air are separated. The suction and the conveyance of the pressurized dissolved water to the injection port 3 are stopped.

[0004]

However, once the operation of generating fine bubbles is stopped, the pump unit A and the bathtub 1 are
The pressurized dissolved water remaining in the pipe forming the water passage 4 between the injection ports 3 is depressurized, and the air dissolved in the bath water is deposited, and the deposited air is ejected during the next operation. Therefore, there is a problem in that a large bubble having a diameter of several cm is generated, which gives a bather discomfort. 9A and 9B show states inside the water channel 4 when the pump unit A is operating and when the pump unit A is stopped. In FIG. 9A, the pressurized dissolved water B is present in the water channel 4. However, (b) shows a state in which the bath water C and the deposition air D are separated in the water channel 4.

The present invention has been made in view of the above-mentioned problems of the conventional example, and an object thereof is to supply stable fine bubbles in which large bubbles are not mixed even when the pump unit is restarted. (EN) Provided is a fine bubble generating device capable of taking a comfortable bath.

[0006]

In order to solve the problems of the above-mentioned conventional examples and achieve the object of the present invention, the fine bubble generating apparatus of the present invention comprises a hot water inlet 2 and an injection port 3 provided in a bathtub 1. An air supply unit 6 with a solenoid valve 5, a pump, and an accumulator 8 are arranged in this order from the hot water inlet 2 side in a water channel 4 that connects to the water passage 4. The pump 7 is operated and the solenoid valve 5 of the air supply unit 6 is opened. 2 for sucking air supplied from the air supply unit 6
Dissolved under pressure with the pump 7 in the bath water sucked from
An operation switch 9 is used in a fine bubble generator in which the pressurized dissolved water of air is separated from excess air by an accumulator 8 and the pressurized dissolved water is decompressed by the injection port 3 to generate fine bubbles in the bath 1. Solenoid valve 5 by the operation start signal from
Means for opening the pump 7 and operating the pump 7, closing the solenoid valve 5 in response to an operation stop signal from the operation switch 9 and stopping the operation of the pump 7 after a certain time delay from the closing of the solenoid valve 5. It is characterized in that a control unit 11 including 10 is provided.

A hot water inlet 2 and a jet port 3 provided in the bathtub 1
An air supply unit 6 with a solenoid valve 5, a pump 7, and an accumulator 8 are arranged in this order from the hot water inlet 2 side in a water passage 4 that connects with the solenoid valve 5 of the air supply unit 6 while operating the pump 7. Open and the air supplied from the air supply unit 6 is melted under pressure in the bath water sucked from the hot water inlet 2 by the pump 7, and the pressurized melted water of air and the surplus air are separated by the accumulator 8 and pressurized. In a fine bubble generator for decompressing dissolved water at the jet port 3 to generate fine bubbles in the bathtub 1, the water channel 4 is provided between the accumulator 8 and the jet port 3 of the water channel 4 and the drain port 3 side and drainage. A switching valve 12 for switching to the portion 15 side is provided, the solenoid valve 5 is opened by an operation start signal from the operation switch 9 and the pump 7 is operated, and the solenoid valve 5 is closed by an operation stop signal from the operation switch 9. Of the solenoid valve 5 After that, the delay means 10 for stopping the operation of the pump 7 after a fixed time delay, and the switching valve 12 is switched so that the drain portion 15 side is opened and the injection port 3 side is closed at the same time when the solenoid valve 5 is closed and the operation of the pump 7 is stopped. Switching valve 12
It is also preferable that the controller 11 is provided with a switching controller 13 that switches the drain part 15 side to be closed and the injection port 3 side to be open.

[0008]

According to the present invention having the above structure, however, the solenoid valve 5 is activated by the operation start signal from the operation switch 9.
Means for opening the pump 7 and operating the pump 7, closing the solenoid valve 5 in response to an operation stop signal from the operation switch 9 and stopping the operation of the pump 7 after a certain time delay from the closing of the solenoid valve 5. Since the control unit 11 provided with 10 is provided, when the operation switch 9 is operated and the operation stop signal is sent, the electromagnetic valve 5 is closed and the air supply is stopped. Pump 7 operates for a certain time,
When the pressure-dissolved water of the air in the water channel 4 is discharged into the bathtub 1, the operation of the pump 7 is stopped, and when the operation switch 9 is operated again to restart the pump unit, large bubbles are generated. Can be prevented from mixing.

A switching valve 12 is provided between the accumulator 8 of the water channel 4 and the injection port 3 to switch the water channel 4 between the injection port 3 side and the drainage section 15 side, and a solenoid valve is operated by an operation start signal from the operation switch 9. 5 is opened and the pump 7 is operated, the electromagnetic valve 5 is closed by an operation stop signal from the operation switch 9, and the delay means 10 stops the operation of the pump 7 after a certain time delay from the closing of the electromagnetic valve 5. Simultaneously with the closing of the solenoid valve 5, the switching valve 12 is switched so that the drain portion 15 side is open and the injection port 3 side is closed, and when the operation of the pump 7 is stopped, the switching valve 12 is closed and the drain port 15 side is closed. Control unit 1 provided with a switching control means 13 for switching so that the side is opened.
In the device provided with 1, when the operation switch 9 is operated and the operation stop signal is sent to the control unit 11, the solenoid valve 5 is closed and the air supply is stopped. For a period of time, the pump 7 is operated and the switching valve 12 is switched at the same time as the supply of air is stopped, and the supply of fine bubbles to the bathtub 1 side is stopped at the same time as the operation of the operation switch 9 is stopped. When the pressurized dissolved water is drained to the drain portion 15 side and the pressurized dissolved water of the air in the water channel 4 is completely drained to the drain portion 15 side, the operation of the pump 7 is stopped,
Along with this, the switching valve 12 is closed on the drain portion 15 side and opened on the injection port 3 side. Therefore, when the operation switch 9 is operated again to restart the pump unit, large bubbles can be prevented from entering.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the accompanying drawings. 1 to 3 show one embodiment of the present invention. As shown in FIG. 1, a bathtub 1 is provided with a hot water inlet 2 and a jet port 3. The hot water inlet 2 and the jet port 3 are connected to a water channel 4.
Are connected to each other by a pipe constituting the. An air supply unit 6 with a solenoid valve 5, a pump 7, and an accumulator 8 are arranged in this water path 4 in this order from the hot water inlet 2 side. In FIG. 1, 16 is a motor for operating the pump 7, and 14 is an exhaust portion provided in the accumulator 8. Reference numeral 11 in the figure is a control unit. Then, a part of the pipes forming the water channel 4, the pump 7, the motor 16, the accumulator 8 with the exhaust unit 14, the control unit 11, and the like are incorporated in the pump unit A.

Reference numeral 9 in the drawing denotes an operation switch, and in the embodiment shown in the accompanying drawings, an example in which it is mounted on the flange portion of the bathtub 1 is shown, but the mounting position is not limited to the flange portion of the bathtub 1. , Various other mounting points can be selected. FIG. 2 shows a block circuit diagram of the above-described embodiment of the present invention. When a signal from the operation switch 9 is sent to the control unit 11, the solenoid valve 5 receives the signal from the control unit 11.
Is opened and closed, and the motor 16 for operating the pump 7 is turned on,
It is designed to be turned off. Here, in the present embodiment, the control unit 11 is provided with the delay means 10 for delaying when the motor 16 for operating the pump 7 is turned off.

FIG. 3 is a time chart showing the operation of the above embodiment of the present invention. The operation of this embodiment will be described below based on this time chart. First, when the operation switch 9 is operated to start the operation and the operation switch 9 is turned on, an operation start signal from the operation switch 9 is sent to the control unit 11, and by the control signal from the control unit 11,
At the same time when the solenoid valve 5 is opened, the motor 16 is turned on and the pump 7 is operated. Therefore, the bath water in the bathtub 1 is sucked from the hot water inlet 2, and the air in the atmosphere is sucked from the air supply unit 6 and sucked into the pump 7. Bath water and air drawn into the pump 7 is about 6 kg inside the pump 7.
/ Cm ² and the air is pressurized and dissolved in the bath water and sent to the injection port 3 side. Along the way, accumulator 8
Is rectified to separate the pressurized dissolved water of air from the surplus air, the surplus air is exhausted to the atmosphere from the exhaust unit 14, and only the pressurized dissolved water is conveyed to the injection port 3. Here, there is a case where the exhaust unit 14 partially discharges the water together with the exhaust. The pressurized dissolved water sent to the injection port 3 through the accumulator 8 is depressurized by the pressurized dissolved water of air at the injection port 3, and about 10 wire meshes of about 100 mesh built in the injection port 3 are bundled. By passing through a net cartridge (not shown), fine bubbles having a diameter of about 10 μ are generated and are discharged into the bath 1.

The fine bubbles are generated in the bathtub 1 in this way. When it is desired to stop the generation of the fine bubbles, the operation switch 9 is turned on again by operating the operation switch 9, and the operation stop signal is sent to the control unit 11. To the solenoid valve 5 at the same time when the operation of the operation switch 9 is stopped by the signal from the control unit 11.
Is closed and the air supply is stopped, but the control means 11
The delaying means 10 provided in the above makes it possible to stop the operation of the pump 9 by turning off the motor 16 after a fixed time elapses from the closing of the solenoid valve 5. Therefore, the operation switch 9 is operated to stop and the air supply is stopped at the same time as the operation stop signal is sent. However, the operation of the pump 7 is continued for a certain period of time after the air supply is stopped, and the air in the water channel 4 is added. The pressure-dissolved water is discharged into the bath 1. Then, the pressurized dissolved water of the air in the water channel 4 is discharged into the bath 1 and then the pump 7 is stopped. For this reason, the delay time until the operation of the pump 7 is stopped is determined in advance at the time when the pressurized dissolved water of the air in the water channel 4 is completely discharged into the bathtub 1, and at the same time or a little less than this. The operation of the pump 7 is stopped after a delay. As the delay means 10, for example, a timer or a microcomputer can be used. By providing the delay unit 10 as described above and stopping the operation of the pump 7 after continuing the operation of the pump 7 for a certain period of time after stopping the supply of air, no pressurized dissolved water of air remains in the water channel 4. When the pressure-dissolved water remains in the water channel 4 while the operation is stopped, the pressure-dissolved water is decompressed and the dissolved air is deposited, so that the water and the air are separated and remain in the water channel 4. As a result, when the operation switch 9 is re-operated and the pump unit A is restarted, the air deposited in the water channel 4 in the initial stage of the restart becomes a large bubble from the injection port 3. Therefore, it is possible to eliminate the problem that the liquid is discharged into the bathtub 1 as a result.

Next, another embodiment of the present invention will be described with reference to FIGS. Also in this embodiment, FIG.
As shown in FIG. 3, the hot water inlet 2 and the injection port 3 provided in the bathtub 1 are connected to each other by a pipe forming a water channel 4, and the water channel 4
An air supply unit 6 with a solenoid valve 5, a pump 7 driven by a motor 16, and an accumulator 8 with an exhaust unit 14 are arranged in the middle of the water intake port 2 side in order.
The basic configuration in which a part of the piping constituting the pump, the pump 7, the motor 16, the accumulator 8 with the exhaust unit 14, the control unit 11 and the like are incorporated in the pump unit A is the same as in the above-described embodiment. In addition to the above-described configuration, in the present embodiment, a switching valve 12 such as an electric valve that switches the water passage 4 between the injection port 3 side and the drain portion 15 side is provided between the accumulator 8 of the water channel 4 and the injection port 3. It is provided.

FIG. 5 shows a block circuit diagram of this embodiment. When a signal from the operation switch 9 is sent to the control unit 11, the signal from the control unit 11 opens and closes the solenoid valve 5,
Further, the motor 16 for operating the pump 7 is turned on and off, and the switching valve 12 is opened and closed.
Here, in the present embodiment, the control unit 11 has a delay means for closing the electromagnetic valve 5 by the operation stop signal from the operation switch 9 and stopping the operation of the pump 7 after a certain time delay from the closing of the electromagnetic valve 5. 10 and the switching valve 1 at the same time when the solenoid valve 5 is closed
Switching control means for switching 2 so that the drain portion 15 side is open and the injection port 3 side is closed, and when the operation of the pump 7 is stopped, the switching valve 12 is switched so that the drain port 15 side is closed and the injection port 3 side is open. And 13 are provided.

FIG. 6 is a time chart showing the operation of this embodiment. The operation of this embodiment will be described below based on this time chart. First, when the operation switch 9 is operated to start the operation and the operation switch 9 is turned on, an operation start signal from the operation switch 9 is sent to the control unit 11, and the solenoid valve 5 is operated by the control signal from the control unit 11. At the same time, the motor 16 is turned on and the pump 7 is operated. Therefore, the bath water in the bathtub 1 is sucked from the hot water inlet 2, and the air in the atmosphere is sucked from the air supply unit 6 and sucked into the pump 7. The bath water and air sucked into the pump 7 are pressurized to about 6 kg / cm ² inside the pump 7, and the air is pressurized and dissolved in the bath water and sent to the injection port 3 side. On the way, rectification is performed by the accumulator 8 to separate pressurized dissolved water of air and surplus air, the surplus air is exhausted to the atmosphere from the exhaust unit 14, and only the pressurized dissolved water is conveyed to the injection port 3. To be done. Here, there is a case where the exhaust unit 14 partially discharges the water together with the exhaust. The pressurized dissolved water sent to the injection port 3 through the accumulator 8 is depressurized by the pressurized dissolved water of air at the injection port 3, and about 10 wire meshes of about 100 mesh built in the injection port 3 are bundled. By passing through a net cartridge (not shown), fine bubbles having a diameter of about 10 μ are generated and are discharged into the bath 1.

The fine air bubbles are generated in the bathtub 1 in this way. When it is desired to stop the generation of the fine air bubbles, the operation switch 9 is turned on again by operating the operation switch 9. To the solenoid valve 5 at the same time when the operation of the operation switch 9 is stopped by the signal from the control unit 11.
Is closed and the supply of air is stopped, and at the same time, the switching valve control means 13 switches the switching valve 12 so that the drain portion 15 side is open and the injection port 3 side is closed.
The delaying means 10 provided in the above makes it possible to stop the operation of the pump 7 by turning off the motor 16 after a certain time delay from the closing of the solenoid valve 5. Therefore, the operation switch 9 is operated to stop and the air supply is stopped at the same time as the operation stop signal is sent. However, the operation of the pump 7 is continued for a certain period of time after the air supply is stopped, and the air in the water channel 4 is added. The pressure-dissolved water is drained from the drainage unit 15 to the outside of the system. And waterway 4
The pump 7 stops its operation after the pressurized dissolved water of the inside air is drained from the drainage section 15. When the operation of the pump 7 is stopped, the switching valve control means 13 switches the switching valve 12 so that the drain portion 15 side is closed and the injection port 3 side is opened. Therefore, the delay time until the operation of the pump 7 is stopped is determined in advance at the time when the pressurized dissolved water of the air in the water channel 4 is completely discharged from the drainage unit 15, and at the same time or a little less than this. The operation of the pump 7 is stopped after a delay. As the delay means 10, for example, a timer or a microcomputer can be used. By providing the delay means 10 as described above, the pump 7 can be operated for a certain period of time after the air supply is stopped.
The operation of the pump 7 is stopped after the operation of No. 1 is continued, and the switching valve control means 13 causes the switching valve 12 to be closed at the same time as the electromagnetic valve 5 is closed on the drain side and the injection port 3 side. By switching and switching the operation of the pump 7 so that the drain valve side is closed and the injection port 3 side is opened when the operation of the pump 7 is stopped, no pressurized dissolved water of air remains in the water channel 4, and when the operation is stopped. When the pressure-dissolved water remains in the water channel 4, the pressure-dissolved water is decompressed and the dissolved air is deposited, so that the water channel 4
As a result, the situation where water and air are separated and left inside is not caused, and as a result, when the operation switch 9 is re-operated to restart the pump unit A, the water channel 4 is restarted at the initial stage of restarting. This prevents the air that has been deposited inside from becoming a large bubble from the injection port 3 and being discharged into the bathtub 1. Moreover, since the switching valve 12 is switched so that the drain portion 15 side is open and the injection port 3 side is closed at the same time as the operation of the operation switch 9 is stopped, the injection from the injection port 3 into the bathtub 1 is stopped. At the same time when the operation of the operation switch 9 is stopped, the injection from the injection port 3 is stopped, and even though the operation is stopped, the injection is performed from the injection port 3 for a certain period of time, which makes the user feel uncomfortable. There is no such thing.

[0018]

According to the first aspect of the present invention, the solenoid valve is opened by the operation start signal of the operation switch and the pump is operated, and the solenoid valve is closed by the operation stop signal of the operation switch. In addition, since a control unit is provided with a delay means that stops the pump operation after a certain time delay from the closing of the solenoid valve, when the operation switch is operated and a stop signal is sent, the solenoid valve turns off. Then, the supply of air is stopped, but the pump continues to operate for a certain period of time after the supply of air is stopped, and the operation of the pump is stopped after the pressurized dissolved water of air in the water channel is discharged into the bathtub. Therefore, when the operation switch is re-operated and the pump unit is restarted, it is possible to prevent large bubbles from being mixed into the bathtub from the injection port, and it is possible to comfortably bathe due to the generation of fine bubbles.

According to the second aspect of the present invention, a switching valve is provided between the accumulator of the water channel and the injection port to switch the water channel between the injection port side and the drainage side, and the electromagnetic switch is activated by the operation start signal from the operation switch. The valve is opened and the pump is operated, the electromagnetic valve is closed by the operation stop signal from the operation switch, and the delay means for stopping the operation of the pump after a certain time delay from the closing of the electromagnetic valve, and the closing of the electromagnetic valve. At the same time, the switching valve is switched so that the drain side is opened and the injection side is closed, and the switching valve is switched so that the drain side is closed and the injection side is opened when the pump is stopped. Since the control unit is provided, when the operation switch is operated and an operation stop signal is sent to the control unit, the solenoid valve closes and the air supply is stopped. When the operation is continued and the air supply is stopped, the switching valve is switched, the operation of the operation switch is stopped, and at the same time, the supply of fine bubbles to the bathtub side is stopped, and the pressurized dissolved water of the air in the water channel is drained. Drained to the side,
When the pressurized dissolved water of the air in the water channel is completely drained to the drain side, the pump operation is stopped, and accordingly, the switching valve is such that the drain side is closed and the injection port side is open. As a result, when the operation switch is re-operated and the pump unit is restarted, large bubbles can be prevented from mixing into the bathtub from the injection port, and comfortable bathing due to the generation of fine bubbles can be achieved. If the switch is operated to stop,
At the same time, the discharge from the injection port is stopped, so that even if the operation is stopped, the injection is performed from the injection port for a certain period of time and the user does not feel discomfort. After the operation of stopping the operation, the pressurized dissolved water accumulated in the water channel can be discharged to the outside of the system, and as a result, the bath can be more comfortably bathed.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention.

FIG. 2 is a block diagram of the above.

FIG. 3 is a time chart showing the same operation.

FIG. 4 is a schematic configuration diagram of another embodiment of the present invention.

FIG. 5 is a block diagram of the same.

FIG. 6 is a time chart showing the same operation.

FIG. 7 is a schematic configuration diagram of a conventional example.

FIG. 8 is a time chart showing the same operation.

9 (a) and 9 (b) are explanatory views showing states in the water channel when the pump unit is operating and when the pump unit is stopped in the conventional example.

[Explanation of symbols]

 1 Bathtub 2 Hot water inlet 3 Injection port 4 Water channel 5 Solenoid valve 6 Air supply part 7 Pump 8 Accumulator 9 Operation switch 10 Delay means 11 Control part 12 Changeover valve 13 Changeover control means 15 Drainage part

Claims (2)

[Claims] 1. An air supply unit with a solenoid valve, a pump, and an accumulator are arranged in this order from the water intake port side in a water passage connecting the water intake port and the injection port provided in a bathtub. Open the solenoid valve of the supply part to pressurize the air supplied from the air supply part into the bath water sucked in from the hot water inlet with a pump, separate the pressurized dissolved water of the air from the excess air with an accumulator, and add it. In a fine bubble generator that decompresses the pressure-dissolved water at the injection port to generate fine bubbles in the bath, the electromagnetic valve is opened by the operation start signal of the operation switch and the pump is operated, A fine air bubble generator comprising a control unit provided with a delay means for closing the solenoid valve in response to an operation stop signal and for stopping the operation of the pump after a certain time delay from the closing of the solenoid valve. . 2. An air supply unit with a solenoid valve, a pump, and an accumulator are arranged in this order from the water intake port side in a water channel connecting the water intake port and the injection port provided in the bathtub, and the pump is operated and the air is supplied. Open the solenoid valve of the supply part to pressurize the air supplied from the air supply part into the bath water sucked in from the hot water inlet with a pump, separate the pressurized dissolved water of the air from the excess air with an accumulator, and add it. In a fine bubble generator that decompresses pressure-dissolved water at the injection port to generate fine bubbles in the bath, switching between switching the water passage between the accumulator of the water passage and the injection outlet A valve is provided, the solenoid valve is opened by the operation start signal from the operation switch and the pump is operated, the solenoid valve is closed by the operation stop signal from the operation switch, and the po The delay means to stop the pump operation and the switching valve is switched so that the drain side is open and the injection port side is closed at the same time when the solenoid valve is closed, and the switch valve is injected with the drain side closed when the pump stops operating. A fine air bubble generator, comprising a control unit having a switching control means for switching so that the mouth side is opened.