JP2016087524A - Fine bubble generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fine bubble generator which enables even a liquid injected first after a start-up to contain a large amount of fine bubbles.SOLUTION: The fine bubble generator includes a liquid introduction pipe 24, a gas injection part 4 for injecting a gas into the liquid introduction pipe, a booster pump 21 for pressurizing and pressure-feeding a gas-liquid mixture formed by introducing a gas into the liquid in the liquid introduction pipe by the gas injection part, a dissolving tank 1 for pressure-dissolving the liquid and the gas in the gas-liquid mixture fed by the booster pump, a liquid leading-out pipe 41 for leading out the liquid in the dissolving tank, a fine bubble generation nozzle 43 for generating fine bubbles in the liquid in the liquid leading-out pipe and injecting the liquid containing the fine bubbles, a check valve 23 provided in the liquid introduction pipe and configured to permit the flow of the liquid from a liquid supply source to the booster pump while blocking a flow in a reverse direction, a solenoid valve 42 for opening/closing the liquid leading-out pipe, and a control unit 5 for controlling the solenoid valve and closing the solenoid valve when the booster pump is stopped.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fine bubble generating apparatus that is generally used for cleaning, and particularly used for cleaning parts in machining.

Conventionally, as a method of generating fine bubbles called microbubbles or nanobubbles, a swirling flow method in which gas and liquid are swirled at a high speed and bubbles having a micro particle diameter are generated by shearing force, or a gas compressed in a liquid at a stroke is used. In addition to the pressure dissolution method that generates bubbles with a micro particle size by releasing, an ultrasonic method, a fine pore method, and the like are known.
Thus, as an example of an apparatus for generating fine bubbles by a pressure dissolution method, there is a fine bubble generating apparatus disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2012-254407). This fine bubble generating device is a fine bubble generating device that jets fine bubbles into the liquid in the liquid tank after the gas is pressurized and dissolved in the liquid flowing through the pipeline, and the liquid is supplied from the liquid supply source. A suction pipe, a gas introduction part that sucks gas and introduces the gas into the liquid in the suction pipe, and pressurizes the gas-liquid mixed liquid in which the gas is introduced into the liquid in the suction pipe by the gas introduction part. Pressurizing pump for pumping, gas-liquid dissolving tank for pressurizing and dissolving the liquid and gas in the gas-liquid mixed liquid sent by this pressurizing pump, and gas-liquid dissolution pressurized and dissolved by this gas-liquid dissolving tank It is comprised from the bubble generation nozzle which decompresses a liquid and generate | occur | produces a fine bubble.
In addition, when generating fine bubbles by the swirling flow method, a dedicated nozzle is used. For example, the additional device of the swirl type fine bubble generating device shown in Patent Document 2 (Japanese Patent Laid-Open No. 2010-158680) is used as the above-mentioned fine bubbles. Attach to the bubble generation nozzle of the bubble generator.

JP 2012-254407 A JP 2010-158680 A

  However, in the conventional fine bubble generator, when the pressurization pump is stopped, the internal pressure of the entire flow path including the gas-liquid dissolution tank decreases. For this reason, immediately after resuming operation of the pressurizing pump, the internal pressure of the entire flow path does not reach a predetermined value, and the liquid that is ejected first has a problem that the content of fine bubbles is reduced. It was.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a fine bubble generating device that contains a large amount of fine bubbles even when the liquid is first ejected after the start of operation.

In order to achieve the above object, the fine bubble generator of the present invention comprises:
A liquid introduction pipe into which liquid is introduced from a liquid supply source;
A gas injection part for injecting gas into the liquid in the liquid introduction pipe;
A pressurizing pump for pressurizing and feeding the gas-liquid mixture in which the gas is introduced into the liquid in the liquid introduction pipe by the gas injection unit;
A dissolution tank for pressure-dissolving the liquid and gas in the gas-liquid mixture sent by the pressure pump;
A liquid outlet pipe from which a liquid having an increased concentration of dissolved gas is derived in the dissolution tank;
A fine bubble generating nozzle for generating fine bubbles in the liquid in the liquid outlet pipe and injecting a liquid containing the fine bubbles;
A check valve provided in the liquid introduction pipe, allowing a flow of liquid in a direction from the liquid supply source toward the pressurizing pump and preventing a reverse flow;
An electromagnetic valve for opening and closing the liquid outlet pipe;
When the solenoid valve is controlled and the pressurizing pump is stopped, the controller that closes the solenoid valve;
It is comprised from these.

  When driving the pressurizing pump, if the internal pressures of the liquid introduction pipe, the dissolution tank, and the liquid outlet pipe are lower than predetermined values, the control unit operates the pressurization pump with the electromagnetic valve closed. It is preferable to drive the solenoid valve after the internal pressure reaches a predetermined value.

In addition, it is preferable that the internal pressures of the liquid introduction pipe, the dissolution tank, and the liquid lead-out pipe are 0.2 to 0.4 [MPa].

  According to the fine bubble generating device of the present invention, the internal pressure of the entire flow path is maintained even when the pressurization pump is stopped. Many bubbles can be included.

It is a figure which shows the whole structure of a microbubble generator. It is a figure for demonstrating exchange of the signal between members, such as a control part and other sensors. It is a figure which shows the timing chart of the pressure control by a control part. It is a graph which shows distribution according to particle size about the number of fine bubbles contained per 1 milliliter of jetting liquid, when the internal pressure of a dissolution tank is set as 0.2MPa and 0.4MPa. It is a graph which shows distribution according to particle size about the number of fine bubbles contained per 1 milliliter of propellants when the internal pressure of a dissolution tank is set as 0.6 MPa and 0.8 MPa.

  Embodiments of a microbubble generator according to the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an overall configuration of the fine bubble generating device 10. As shown in the figure, the fine bubble generating apparatus 10 includes a dissolution tank 1, a liquid introduction unit 2, a gas injection unit 3, a liquid lead-out unit 4, and a control unit 5 (see FIG. 2).

  The dissolution tank 1 is a pressure vessel in which a mixture of water 9 and air is accommodated, and is a tank for increasing oxygen concentration in the water 9 by dissolving oxygen in the air in the water 9. The water 9 is industrial water here, and is supplied into the dissolution tank 1 by the liquid introduction part 2. LS1L provided in the dissolution tank 1 is a sensor for detecting the lower limit when the water level of 9 in the dissolution tank 1 is lowered, and LS1U is a sensor for detecting that the water level has increased. . The dissolution tank 1 is provided with a pressure sensor PS1 for measuring the internal pressure of the dissolution tank 1. The contents of control based on the detection of each sensor will be described later.

  The liquid introduction unit 2 includes a pressurizing pump 21, a strainer 22, a check valve 23, and a liquid introduction pipe 24. The pressurizing pump 21, the strainer 22, and the check valve 23 are provided in the middle of the liquid introduction pipe 24, one end of the liquid introduction pipe 24 is connected to the water tank 7, and the other end of the liquid supply pipe 24 is It is connected to the opening 11 at the top of the dissolution tank 1 and constitutes a supply path for supplying water 9 of the water tank 7 to the dissolution tank 1.

  When the pressurizing pump 21 is driven, the water 9 in the water tank 7 is sucked into the liquid introduction pipe 24 by the pressurizing pump 21. The water 9 sucked into the liquid introduction pipe 24 flows in the direction indicated by the arrow a, is filtered when passing through the strainer 22, and then passes through the check valve 23. The check valve 23 allows the flow of the water 9 only in the direction indicated by the arrow b and blocks the flow in the opposite direction. The water 9 after passing through the check valve 23 is a gas injection part. 3 is a mixture of water 9 and air. This mixture flows in the direction indicated by the arrow c, is pressurized to a pressure of, for example, about 0.3 [MPa] by the pressure pump 21, flows in the direction indicated by the arrow d, and is sent to the dissolution tank 1.

  The gas injection unit 3 includes a gas introduction pipe 31, an electromagnetic valve 32, a check valve 33, and a gas suction port 34. The gas introduction pipe 31 joins the liquid introduction pipe 24 at the AC point A and is an introduction path for sending the air sucked from the gas suction port 34 to the liquid introduction pipe 24, and is indicated by an arrow e by the pressurizing pump. Send air in the direction. Then, a mixture of air and water 9 is generated at the merge point A. The gas introduction pipe 31 is provided with an electromagnetic valve 32 and a check valve 33. The check valve 33 allows the flow of air only in the direction indicated by the arrow f, and blocks the flow of air and water 9 in the opposite direction. The electromagnetic valve 32 switches between the derivation of air from the gas inlet 34 to the liquid introduction pipe 24 and its prohibition by opening and closing the gas flow path of the liquid introduction pipe 31.

  The liquid lead-out unit 4 includes a liquid lead-out pipe 41, an electromagnetic valve 42 provided in the liquid lead-out pipe 41, and a fine bubble generation nozzle 43. One end of the liquid outlet pipe 41 is connected to an opening (not shown) provided at the bottom of the dissolution tank 1, and the mixture of air and water 9 in the dissolution tank 1 flows in the direction indicated by the arrow g. A fine bubble generating nozzle 43 is connected to the other end of the liquid outlet pipe 41. The electromagnetic valve 42 switches between the derivation of the liquid from the dissolution tank 1 to the fine bubble generating nozzle 43 and the prohibition thereof by opening and closing the liquid flow path of the liquid derivation tube 42. When the electromagnetic valve 42 is in the open state, a mixture of air and water 9 flows in the direction indicated by the arrow h, and a liquid containing fine bubbles is ejected from the fine bubble generating nozzle 43. The fine bubble generating nozzle 43 is a well-known one configured to generate fine bubbles by a swirling flow method, and uses, for example, an additional device of a swirling fine bubble generating device disclosed in Japanese Patent Application Laid-Open No. 2010-158680. .

  FIG. 2 is a diagram for explaining exchange of signals between the control unit 5 and other members such as sensors, and FIG. 3 is a diagram illustrating a timing chart of pressure control by the control unit 5. As shown in FIG. 2, the control unit 5 receives signals from the liquid level lower limit detection sensor LS1L, the liquid level upper limit detection sensor LS1U, and the pressure sensor PS1, and opens and closes the electromagnetic valve 32 and the electromagnetic valve 42 based on the received signals. Control. The control unit 5 receives an operation instruction signal from the operation unit and controls the operation of the pressure pump 21. Here, the operation instruction signal of the pressurizing pump 21 is generated when a switch or the like provided in the operation unit is operated by the operator.

  As shown in FIG. 3, when the pressure pump drive instruction signal is received at time T1, the operation of the pressure pump 21 is started and signals from the liquid level lower limit detection sensor LS1L, the liquid level upper limit detection sensor LS1U and the pressure sensor PS1 are displayed. Accept. At this time, when the internal pressure of the dissolution tank 1 does not reach a predetermined value (for example, 0.3 MPa), the electromagnetic valve 42 maintains a closed state. Thereby, the internal pressure of the dissolution tank 1 rises. Further, when a predetermined amount of water 9 is not stored in the dissolution tank 1, the electromagnetic valve 32 is kept closed. Thereby, the water level in the dissolution tank 1 rises.

  At time T2, when the water level of the dissolution tank 1 rises to the lower limit value and the liquid level of the water 9 is detected by the liquid level lower limit detection value sensor LS1L, an ON signal is output from the liquid level lower limit detection sensor LS1L. When this ON signal is received, assuming that a predetermined amount of water 9 has been stored in the dissolution tank 1, an intermittent operation instruction signal is issued to the electromagnetic valve 32, and the electromagnetic valve 32 repeats opening and closing at intervals of 1 second. At the open timing, air is sucked from the gas suction port 34, so that a mixture of air and water 9 is supplied to the dissolution tank 1. On the other hand, since the suction of air is blocked at the timing of the closed state, only water 9 is supplied to the dissolution tank 1.

  At a time T3, when a predetermined amount of water 9 is stored in the dissolution tank 1 and the pressure in the dissolution tank 1 rises to a predetermined value, an opening instruction signal is issued to the electromagnetic valve 42, and the electromagnetic valve 42 is opened. Thus, the liquid containing the fine bubbles is ejected from the fine bubble generating nozzle 43.

  At time T4, when the water level of the dissolution tank 1 rises to the upper limit value due to some trouble during injection and the liquid level of the water 9 is detected by the liquid level upper limit detection sensor LS1U, the liquid level upper limit detection sensor LS1U. An ON signal is output from. When this ON signal is received, an opening instruction signal is issued to the electromagnetic valve 32, assuming that the amount of water in the dissolution tank 9 exceeds a predetermined amount, and the electromagnetic valve 32 stops intermittent operation and enters an open state. Thereby, since the ratio of the air supplied to the dissolution tank 1 becomes high, the water level of the dissolution tank 1 falls as a result.

  At time T5, when the water level of the dissolution tank 1 falls and the liquid level of the water 9 is no longer detected by the liquid level upper limit detection sensor LS1U, an OFF signal is output from the liquid level upper limit detection sensor LS1U. When this OFF signal is received, assuming that the amount of water in the dissolution tank 9 has returned to a predetermined amount, an intermittent operation instruction signal is issued again to the electromagnetic valve 32, and the electromagnetic valve 32 repeats opening and closing at intervals of 1 second.

  At time T6, when the water level in the dissolution tank 1 drops to the lower limit value due to some trouble during the injection and the liquid level of the water 9 is not detected by the liquid level lower limit detection sensor LS1L, the liquid level lower limit detection sensor LS1L Outputs an OFF signal. When this OFF signal is received, the solenoid valve 32 is issued a closing instruction signal because the amount of water in the dissolution tank 9 is insufficient, and the solenoid valve 32 stops intermittent operation and enters a closed state. Thereby, since the ratio of the water 9 supplied to the dissolution tank 1 becomes high, the water level of the dissolution tank 1 rises as a result.

  At time T7, when the water level of the dissolution tank 1 rises and the liquid level of the water 9 is detected by the liquid level lower limit detection sensor LS1L, an ON signal is output from the liquid level upper limit detection sensor LS1L. When this ON signal is received, assuming that the amount of water in the dissolution tank 9 has returned to a predetermined amount, an intermittent operation instruction signal is issued again to the electromagnetic valve 32, and the electromagnetic valve 32 repeats opening and closing at intervals of 1 second.

  When the pressurization pump stop instruction signal is received at time T8, the operation of the pressure pump 21 is stopped, and a close instruction signal is issued to the solenoid valve 32 and the solenoid valve 42, and the solenoid valve 32 and the solenoid valve 42 are Closed. Thereby, the internal pressure of the whole microbubble generator 10 is maintained at a predetermined value.

  At time T9, when the pressurization pump re-drive instruction signal is received from the micro-bubble generating nozzle 43 to restart the injection of the liquid containing the micro-bubbles, the operation of the pressure pump 21 is restarted and the liquid level lower limit detection sensor LS1L, The signals of the liquid level upper limit detection sensor LS1U and the pressure sensor PS1 are received. At this time, the internal pressure of the dissolution tank 1 is maintained at a predetermined value (for example, 0.3 MPa), and an opening instruction signal is issued to the electromagnetic valve 42. When a predetermined amount of water 9 is stored in the dissolution tank 1, an intermittent operation instruction signal is issued to the electromagnetic valve 32. If the internal pressure of the dissolution tank 1 does not reach a predetermined value, the solenoid valve 42 remains closed until the internal pressure of the dissolution tank 1 reaches a predetermined value, and water 9 When a predetermined amount is accommodated, the electromagnetic valve 32 is kept closed until a predetermined amount of water 9 is accommodated in the dissolution tank 1.

  4 and 5 show that the internal pressure of the dissolution tank 1 is 0.2 MPa (upper view of FIG. 4), 0.4 MPa (lower view of FIG. 4), 0.6 MPa (upper view of FIG. 5), and 0.8 MPa ( FIG. 6 is a graph showing the distribution according to particle diameter with respect to the number of fine bubbles contained per milliliter of liquid ejected from the fine bubble generating nozzle 43 when set in the lower diagram of FIG. This result indicates that when the internal pressure of the dissolution tank 1 is 0.2 MPa to 0.4 MPa, a large number of 10 μm fine bubbles are distributed. Can be generated.

  According to the fine bubble generating device 10, since the internal pressure of the entire flow path of the device is maintained even when the pressurizing pump 21 is stopped, high-quality fine bubbles can be stably stabilized immediately after the operation of the pressurizing pump 21 is resumed. Can be supplied. In particular, by setting the internal pressure to 0.2 MPa to 0.4 MPa, a large number of micro bubbles having a micro diameter can be generated.

DESCRIPTION OF SYMBOLS 1 Dissolution tank 2 Liquid introduction part 3 Liquid lead-out part 4 Gas injection part 5 Control part 7 Water tank 9 Water 21 Pressurization pumps 23 and 33 Check valve 24 Liquid introduction pipes 32 and 42 Electromagnetic valve 41 Liquid lead-out pipe 43 Fine bubble generation nozzle

Claims (3)

A liquid introduction pipe into which liquid is introduced from a liquid supply source;
A gas injection part for injecting gas into the liquid in the liquid introduction pipe;
A pressurizing pump for pressurizing and feeding the gas-liquid mixture in which the gas is introduced into the liquid in the liquid introduction pipe by the gas injection unit;
A dissolution tank for pressure-dissolving the liquid and gas in the gas-liquid mixture sent by the pressure pump;
A liquid outlet pipe from which a liquid having an increased concentration of dissolved gas is derived in the dissolution tank;
A fine bubble generating nozzle for generating fine bubbles in the liquid in the liquid outlet pipe and injecting a liquid containing the fine bubbles;
A check valve provided in the liquid introduction pipe, allowing a flow of liquid in a direction from the liquid supply source toward the pressurizing pump and preventing a reverse flow;
An electromagnetic valve for opening and closing the liquid outlet pipe;
When the solenoid valve is controlled and the pressurizing pump is stopped, the controller that closes the solenoid valve;
A microbubble generator characterized by comprising:   When driving the pressurizing pump, if the internal pressure of the liquid introduction pipe, the dissolution tank, and the liquid outlet pipe is lower than a predetermined value, the control unit drives the pressurization pump with the electromagnetic valve closed. 2. The fine bubble generating device according to claim 1, wherein the electromagnetic valve is opened after the internal pressure reaches a predetermined value. 4. The microbubble generator according to claim 1, wherein internal pressures of the liquid introduction pipe, the dissolution tank, and the liquid outlet pipe are 0.2 to 0.4 [MPa].

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