JP4872937B2 - Fine bubble generating apparatus and method - Google Patents

Description

  The present invention relates to a fine bubble generating apparatus and method in which the diameter and generation amount of fine bubbles are stabilized.

  [Non-Patent Document 1] describes the use and effect of fine bubbles in purification, sterilization, and disinfection. In [Non-Patent Document 1], fine bubbles are bubbles called microbubbles having a diameter of 50 micrometers or less, and in general, bubbles in this region have a diameter due to the gas in the bubbles being dissolved into the surrounding liquid phase. Therefore, it is described that the internal pressure becomes high pressure and high temperature due to the effect of surface tension, and a pressure wave is generated with free radicals having high oxidizing power such as OH radicals when extinguished. Hereinafter, a fine bubble is defined as a bubble having a diameter of about 50 micrometers or less.

  In general, as a method for generating fine bubbles, there is known a method in which a gas-liquid two-phase flow of gas and liquid is made into fine bubbles using a swirl flow, a swirl of a swirl flow, stirring, a venturi tube, or the like. Further, there is a method in which a gas-liquid two-phase flow is pressurized and then rapidly reduced in a narrow channel to precipitate dissolved gas as fine bubbles. This method tends to have a higher power consumption per generated bubble amount than other methods, but is distributed in a region where the bubble diameter is relatively small.

In [Patent Document 1], ozone gas is sucked by an ejector and mixed into a liquid phase, and a gas-liquid two-phase flow pressurized by a pump is decompressed by an orifice and injected into a dissolution tank to form fine bubbles. A processing apparatus is disclosed, and it is described that a set pressure at an orifice is 4 kg / cm ² , and an orifice diameter d / pipeline diameter D ratio = 0.4.

  [Patent Document 2] discloses a microbubble generator having a configuration similar to that of [Patent Document 1] and using a orifice having a half-moon shaped slit to generate a fine bubble by performing inverter control of a pump. . It is described that the pump discharge pressure is adjusted to the optimum pressure when the gas is mixed and the discharge amount and the discharge pressure fluctuate by changing the rotation speed of the pump by inverter control.

  [Patent Document 3] describes the generation of fine bubbles that change the cross-sectional area of a narrow channel using a device that can change the channel area of the narrow channel that depressurizes a pressurized gas-liquid two-phase flow. An apparatus is disclosed.

JP-A-10-225696 JP 2003-117365 A Japanese Patent Laid-Open No. 10-99877 “Characteristics of Water and New Utilization Technology”, NTS Corporation, pages 142-146, 2004

  The conventional technique described in [Non-Patent Document 1] describes the characteristics of fine bubbles, but does not disclose a specific method for generating fine bubbles.

  In the prior art described in [Patent Document 1], the mixed water is pressurized on the upstream side of the orifice by a high-pressure pump and is reduced when passing through the orifice to generate fine bubbles. Therefore, there is a problem that cannot be coped with when it is necessary to change the flow rate of the mixed water of ozone fine bubbles. Moreover, since the diameter and generation amount of fine bubbles change when the pressurizing pressure changes, there is a problem that the ozone dissolution efficiency changes and the water treatment performance becomes unstable.

  In the conventional technique described in [Patent Document 2], the pressure applied to the orifice can be controlled by controlling the pump rotation speed with an inverter. 1] When dealing with a change in the flow rate of ozone fine bubble mixed water as in the case of 1], there is a problem that the pressurized pressure is changed and stable fine bubbles cannot be generated.

  In the conventional technique described in [Patent Document 3], the pressure of the orifice flow path is variably adjusted to control the pressurization pressure, and the flow rate of the ozone fine bubble mixed water can be controlled. When the restriction of the flow path changes, the flow rate when passing through the orifice changes, and the amount of pressure reduction in the orifice portion for generating fine bubbles changes. If the balance between pressure and pressure changes, the diameter and amount of microbubbles change, which causes a problem that the ozone dissolution efficiency changes and the water treatment performance becomes unstable. That is, if the channel cross-sectional area of the narrow channel is small, the flow rate cannot be increased, and the amount of bubbles generated is reduced. Conversely, if the channel cross-sectional area is large, the generated bubbles are coarsened. As described above, there is a problem in that stable bubble generation cannot be performed because the amount of generated bubbles is insufficient or the bubble diameter becomes coarse.

  The inventors made a plurality of perforated plates having different numbers of holes, and conducted experiments by boosting the gas-liquid two-phase flow of air and tap water with a high-pressure pump and injecting them into the perforated plates. If they are different, the pressure on the upstream side of the perforated plate changes, and it has been confirmed that the generation amount of fine bubbles changes. In addition, as a result of producing a plurality of perforated plates with the same number of holes and changing the hole diameter and conducting the same experiment, when the hole diameter increases, the bubble diameter distribution of the generated bubbles shifts to the larger bubble side. Make sure you do.

  A first object of the present invention is to provide a fine bubble generating apparatus and method that can stably generate fine bubbles and that are excellent in economy.

  The second object of the present invention is to provide a fine bubble generating apparatus and method for stably generating fine bubbles by changing the number of holes through which the rotation speed of the pump and the gas-liquid two-phase flow can flow. There is.

  A third object of the present invention is to provide a fine bubble generating apparatus and method that can control the inflow pressure and flow rate to the fine bubble generating apparatus and can stably generate fine bubbles.

  In order to achieve the above object, the fine bubble generating device of the present invention includes an inverter for controlling the rotational speed of a pump connected to the gas-liquid two-phase flow generating device, and the passage of the gas-liquid two-phase flow connected to the pump. A perforated plate unit including a driving device for changing the cross-sectional area of the flow path used in the control unit, and a control device for controlling the inverter and the driving device. The driving device is controlled by a command from the control device to control the gas-liquid two-phase. The flow passage cross-sectional area used for the flow passage is changed and the inverter is controlled to maintain the pressurized pressure of the pump within the allowable range to change the flow rate of the gas-liquid two-phase flow.

  A plurality of flow paths provided with a perforated plate are connected in parallel, an open / close valve is provided in each flow path, and the open / close control of the open / close valve is performed to change the cross-sectional area of the flow path through which the gas-liquid two-phase flow passes.

  As a result, the gas-liquid two-phase flow is pressurized with a pump, and injected into the narrow channel to reduce the pressure, thereby precipitating the gas dissolved in the liquid and generating fine bubbles. By changing the number of holes through which the gas-liquid two-phase flow passes, that is, by changing the cross-sectional area of the flow path, the flow rate can be controlled while maintaining the conditions for generating fine bubbles. In this way, the pressurized pressure and the flow rate are controlled by changing the number of holes through which the gas-liquid two-phase flow passes and controlling the inverter to control the rotation speed of the pump.

  As the perforated plate, a perforated plate having a plurality of holes having one or more types of cross-sectional areas and a perforated plate in which holes having different numbers of holes per unit area are distributed may be used.

  Further, the perforated plate can be back-flow washed to avoid clogging of the holes in the perforated plate. In addition, an end face structure that contacts the porous plate is provided on the flow restricting plate, and when the flow restricting plate moves on the surface of the porous plate, the end face structure scrapes off and removes the deposit on the surface of the porous plate. Also good.

  Further, in order to improve the gas dissolution efficiency, a pressure tank in which a pressurized gas-liquid two-phase flow stays is provided in the flow path between the pump and the perforated plate unit, or the gas utilization efficiency is improved. Therefore, when the gas-liquid two-phase flow flows into the porous plate unit by providing a flow channel control plate in the flow channel between the pump and the porous plate unit in order to refine the coarse bubbles flowing out of the porous plate. A swirling flow may be given.

  According to the present invention, when the amount of fine bubbles generated is changed, the rotational speed and flow cross-sectional area of the pump are changed, so that an excessive pressure increase is suppressed by maintaining the pressurizing pressure within a range necessary for generating fine bubbles. Therefore, fine bubbles can be generated efficiently and with a stable bubble diameter distribution.

  Provided are a fine bubble generating device and a method for generating a fine bubble having a stable bubble diameter and generated amount by controlling the pressure and flow rate of a gas-liquid two-phase flow with the fine bubble generating device.

  A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a configuration diagram of a fine bubble generating apparatus according to the present embodiment.

  As shown in FIG. 1, the fine bubble generating apparatus of the present embodiment includes a flow path 9 a connected to a gas-liquid two-phase flow generating apparatus (not shown), a pump 1 connected to the flow path 9 a, and a pump 1. A connected inverter (not shown), a porous plate unit 4 connected to the pump 1 through a flow path 9b, a pressure gauge 5 provided in the flow path 9b, and a drive device 7 installed in the porous plate unit 4; The flow path 9 c connected to the perforated plate unit 4, the flow meter 6 provided in the flow path 9 c, the control device 3, and the input device 8 connected to the control device 3. Here, water is used as the gas-liquid two-phase flow liquid, and air, ozone, nitrogen, oxygen, or carbon dioxide is used as the gas.

  The pressure gauge 5 and the flow meter 6 and the control device 3 are connected by a signal line, and the control device 3 receives signals from the pressure gauge 5 and the flow meter 6. The inverter and drive device 7 and the control device 3 are connected by a signal line, and a control signal is transmitted from the control device 3 to the inverter and drive device 7.

  The perforated plate unit 4 is configured as shown in FIGS. A circular plate-like perforated plate 100 fixed to the wall surface of a perforated plate unit 4 (not shown) and provided with a plurality of straight tubular holes 103 having the same diameter in the range of 0.1 to 5 mm, and FIGS. As shown in FIG. 5, the circular plate-like flow restricting plate 101 is provided so as to rotate around the central axis of the porous plate 100 and to face the porous plate 100, and is connected by the fixed plate 104 at the center of the flow restricting plate 101. The rotary shaft 102 is configured. The rotation shaft 102 is connected to the driving device 7, and the rotation angle is controlled by the driving device 7. As shown in FIG. 4, a hole 103 is formed in a half region of the perforated plate 100, and a flow restricting plate 101 formed in a semicircular shape as shown in FIGS. The number of holes through which the flow can pass changes. In this embodiment, the flow path restriction plate 101 is an example of a semicircular shape, but may be a fan shape. If the diameter of the hole 103 is in the range of 0.5 to 2 mm, the generation of fine bubbles is further stabilized and the generation efficiency is improved.

  The perforated plate 100 may be structured to be fixed to the flow path 9b, and the perforated plate 100 and the flow path restricting plate 101 are in contact with each other as long as no frictional force that hinders the rotation of the flow restricting plate 101 is generated. Yes. Further, when the flow path restricting plate 101 is rotated, the drive device 7 is controlled to move the shaft 102 in the axial direction so that a gap is formed between the porous plate 100 and the flow restricting plate 101, and You may make it water flow by making the flow-path restriction | limiting board 101 contact.

  When the rotation shaft 102 is rotated by controlling the driving device 7, a part of the hole 103 is blocked by the flow path restricting plate 101, so that, for example, the state shown in FIG. 2 is changed to the state shown in FIG. The number of holes used for water flow varies. The number of holes used for water flow is referred to as an effective number of holes for convenience.

  In the example shown in FIGS. 2 to 6, the example in which the flow path restriction plate 101 is rotated is shown, but the flow path restriction plate 101 may be translated in the diameter direction along the porous plate 100. Further, a plurality of elongated flow restricting plates 101 may be provided in the diameter direction of the porous plate 100, and the effective pore count may be changed by rotating the flow restricting plate 101 so as to be parallel or perpendicular to the flow direction. Good.

  In the example shown in FIGS. 2 to 6, the hole 103 provided in the perforated plate 100 has been described as a straight tubular hole. However, like the perforated plate 110 shown in FIG. 7, the cross-sectional area of the intermediate portion of the hole 112 is increased. 8 or a shape in which the cross-sectional area inside the hole of the perforated plate changes in the direction of the flow path, such as a shape in which the cross-sectional area of the intermediate portion of the hole 115 becomes small, such as the perforated plate 113 shown in FIG. May be. When such a perforated plate having a hole shape is used, the pressure change occurs not only between the upstream and downstream sides of the perforated plate but also inside the hole, so that the bubbles can be further refined.

  Further, instead of providing a plurality of holes in the perforated plate, a plurality of slits may be provided. In the example shown in FIG. 9, linear slits 121 having a shape in which holes are connected to the right half side of the porous plate 120 are formed radially. In the example shown in FIG. 10, a plurality of linear slits 123 are formed in the vertical direction of the porous plate 122. In addition, this slit is formed in the shape with which the hole was continued, and does not necessarily need to be a straight line.

By operating a keyboard or the like, the target value Q _B of the fine bubble generation amount is input to the input device 8. Further, an allowable deviation amount ΔQ when the amount of generated fine bubbles deviates from the target value Q _B and a control width ΔN when increasing or decreasing the number of rotations of the pump are input. The input target value Q _B of the fine bubble generation amount, deviation amount ΔQ, and control width ΔN are transmitted to the control device 3. The control device 3 receives the pressure measurement value of the pressure gauge 5 installed in the flow path 9b and the discharge flow rate measurement value of the fine bubble-containing water 11 of the flow meter 6 installed in the flow path 9c.

The control device 3 calculates the discharge flow rate Q _O of the fine bubble-containing water 11 necessary for obtaining the target value Q _B of the fine bubble generation amount. The control device 3 is configured so that the pressurization pressure of the perforated plate unit 4 does not exceed the allowable range of deviation from the set value input from the input device 8 and the rotational speed N of the pump 1 necessary for obtaining the discharge flow rate Q _O. Then, the number of holes of the perforated plate unit 4 is calculated. Based on this calculated value, the control device 3 controls the inverter 2 and the drive device 7.

  The rotation speed command value of the pump 1 is transmitted from the control device 3 to the inverter 2 to control the inverter 2, and the pump 1 is operated according to the rotation speed command value. A control signal is transmitted from the control device 3 to the drive device 7 to control the rotation angle of the flow path restriction plate 101 of the perforated plate unit 4 so that the number of effective holes is calculated.

  The gas-liquid two-phase flow 10 from the gas-liquid two-phase flow generator flows into the flow path 9a, and the gas-liquid two-phase flow 10 in which the gas is pressurized and dissolved by the pump 1 is a perforated plate unit. 4 flows in. The gas-liquid two-phase flow 10 is rapidly depressurized when passing through the perforated plate unit 4, and dissolved gas is deposited to form fine bubbles. Fine bubble-containing water 11 containing fine bubbles is discharged from the flow path 9c.

FIG. 11 is a control flowchart of the first embodiment and shows an operation method for obtaining the fine bubble generation amount Q _B. The operation method of Example 1 will be described in more detail with reference to FIG.

In step S1, the control device 3 uses the numerical value 1 to calculate the fine bubble-containing water from the target value Q _B of the fine bubble generation amount input from the input device 8 and the fine bubble content rate r _{B of} the fine bubble-containing water. 11 discharge flow rate Q _O is determined and the pump is started. Here, the content rate r _B can be obtained in advance by experiments from the relationship between the pressurizing pressure and the hole diameter, or by providing a device for measuring the content rate in addition to the flow meter 6.
(Equation 1)
Q _O = Q _B / r _B (1)
In step S2, the control device 3 compares the measured value Q _f of the discharge flow rate of the fine bubble-containing water 11 measured by the flow meter 6 with the target value Q _O. When the measured value Q _f is lower than the target value Q _O , the process proceeds to step 3S, and when it is higher, the process proceeds to step S4.

In step S3, the control device 3 compares the absolute value of the difference between the target value Q _O and the measured value Q _f with an allowable deviation amount ΔQ, and if the absolute value of this difference is smaller than the deviation amount ΔQ, the flow rate is It judges that it is in the control target range and proceeds to step S5. When the absolute value of this difference is larger than the deviation amount ΔQ, it is determined that the flow rate is insufficient with respect to the control target range, and the inverter 2 is controlled to increase the rotation speed N of the pump 1 by a set control width ΔN. Then, the process returns to step S2.

In step S4, the control device 3 compares the absolute value of the difference between the target value Q _O and the measured value Q _f with the deviation amount ΔQ as in step S3, and _if the absolute value of this difference is smaller than the deviation amount ΔQ. The flow rate is determined to be within the control target range, and the process proceeds to step S5. If the absolute value of the difference is larger than the deviation amount ΔQ, it is determined that the flow rate is excessive with respect to the control target range, and the inverter 2 is controlled to reduce the pump rotational speed N by the set width ΔN. Return to S2.

In step S5, the control device 3 compares the measured value P of the pressure gauge 5 with the pressure lower limit value _{Pmin of the} set value. If the measured value is higher than the lower limit value, the process proceeds to step S6. If it is lower, the drive device 7 is activated to reduce the effective hole number m of the perforated plate unit 4 by the set control width Δm, and the process returns to step S2. The lower limit value P _min is set to 0.3 PMa, for example.

  Here, the pressurization pressure was within an allowable range of 0.1 MPa to 1.0 MPa. Regarding the pressurizing pressure, the range in which fine bubble generation is more stable and advantageous in terms of cost is in the range of 0.3 MPa to 0.7 MPa.

In step S6, the control device 3 compares the measured value P of the pressure gauge 5 with the pressure upper limit value P _{max of the} set value. If the measured value is lower than the upper limit value, the process ends. If it is higher, the drive device 7 is activated to increase the effective hole number m of the perforated plate unit 4 by the set control width Δm, and the process returns to step S2.

  The operation and effect of such control will be described with reference to FIG.

  The broken line in FIG. 12 shows the case where the effective flow rate is changed to change the flow path cross-sectional area and the pump rotational speed control is performed, and the solid line indicates that the flow path cross-sectional area is fixed and the pump rotational speed is fixed. The case where control is performed is shown. Here, the number of effective holes is continuously changed, and the flow path cross-sectional area is changed smoothly.

  The upper diagram in FIG. 12 shows the relationship between the pressurized pressure and the gas-liquid two-phase flow rate, which intersects with the number of effective holes of the same channel cross-sectional area. It shows that the pressure and pressure can be controlled to be substantially constant or within an allowable range. On the other hand, when the cross-sectional area of the flow path is fixed, in order to increase the flow rate of the gas-liquid two-phase flow, it is necessary to increase the pressurization pressure by increasing the rotational speed of the pump. In order to reduce the pressure, it is necessary to lower the pressurization pressure by lowering the rotational speed of the pump.

  Thus, when the flow path cross-sectional area is fixed, in order to change the flow rate of the gas-liquid two-phase flow, it is necessary to change the pressurized pressure, so the conditions for generating fine bubbles change. However, in this embodiment, the pressurized pressure can be controlled to be constant or within an allowable range, and the pore diameter remains the same even if the flow path cross-sectional area is changed. Can be generated. Although FIG. 12 shows that the flow rate control can be performed widely even when the flow path cross-sectional area is fixed, the control width is not so large in practice.

  The lower diagram of FIG. 12 is a diagram showing the relationship of the pump power consumption with respect to the gas-liquid two-phase flow rate, and the pump power consumption can be reduced at a portion where the gas-liquid two-phase flow rate is large and a processing amount is required. Here, it is assumed that the power consumption of the pump is proportional to the product of the pressure and the flow rate.

  According to the present embodiment, when the amount of fine bubbles generated is changed, the number of rotations of the pump and the cross-sectional area of the pump are changed, so that an excessive pressure rise is suppressed by maintaining the pressurizing pressure within a range necessary for generating fine bubbles. Therefore, fine bubbles can be generated efficiently and with a stable bubble diameter distribution.

  A second embodiment of the present invention will be described with reference to FIGS. FIG. 13 is a configuration diagram of the fine bubble generating device of the present embodiment.

  The fine generation apparatus of the present embodiment is configured in the same manner as in the first embodiment, but in this embodiment, instead of installing the perforated plate unit 4, a perforated plate unit 40 is used as a rear stage of the pump 1 in the flow path 9b. A plurality of branch channels are provided, and perforated plates 40-1 to 40-n each having a fixed number of holes via valves 70-1 to 70-n are installed in each branch channel. The plurality of perforated plates 40-1 to 40-n are joined and connected to the flow path 9c. Each of the valves 70-1 to 70-n is connected to the control device 3 through a signal line, and performs opening / closing control of the valves 70-1 to 70-n. Here, when the flow path 9c can be extended for each of the valves 70-1 to 70-n, the plurality of perforated plates 40-1 to 40-n do not necessarily have to merge.

  The number of holes provided in each of the perforated plates 40-1 to 40-n may be changed for each perforated plate, may be the same, or may be partially the same and the rest may be changed. The control device 3 controls the opening and closing of the valves 70-1 to 70-n. The number of valves to be opened can be controlled between 1 and n, and the opening and closing is controlled so as to match the number of effective holes to be set. Even if the number of holes and the hole diameter are the same in the perforated plate, the positions of the holes differ depending on whether they are provided on the outer peripheral side of the perforated plate as shown in FIG. 14 or on the inner peripheral side of the perforated plate as shown in FIG. May be properly used depending on the flow rate. By forming the hole positions in this way, it is possible to use them properly when, for example, it is desired to flow around the inner peripheral side.

  The control of the present embodiment is performed in the same manner as the control flowchart of the first embodiment shown in FIG. When the number of holes of each of the perforated plates 40-1 to 40-n is made equal, the control device 3 increases or decreases the number of open valves 70-1 to 70-n in steps S5 and S6 in FIG. The effective number of holes is controlled in stages. Further, when the number of holes formed in the perforated plates 40-1 to 40-n is different, the opening or closing of the valves 70-1 to 70-n is switched, and the flow path or the hole in which the perforated plate having a large number of holes is installed. The number of effective holes is switched by opening a flow path in which a small number of perforated plates are installed.

  As described above, in the first embodiment, the effective hole number is changed by the rotation of the flow path restriction plate 101. Therefore, a mechanical movable part and a motor are required. In this embodiment, the hole number is changed by opening and closing the valve. Therefore, there is an advantage that the configuration is simplified, reliability is improved, and maintenance is easy.

  The operation and effect of the control as described above will be described with reference to FIG.

  The broken line in FIG. 16 shows the case where the effective hole number is changed stepwise to change the flow passage cross-sectional area stepwise and the rotation speed of the pump is controlled. The solid line shows the flow passage cross-sectional area. This shows a case where the rotation speed control of the pump is performed in a fixed state.

  The upper diagram in FIG. 16 shows the relationship between the pressurized pressure and the gas-liquid two-phase flow rate. When the channel cross-sectional area is changed stepwise by switching the branch channel, the flow of a certain branch channel is shown. It shows that the pressurized pressure can be controlled within the allowable range by changing the flow rate of the gas-liquid two-phase flow by changing the rotational speed of the pump with the path cross-sectional area and switching the flow path cross-sectional area. . That is, when the pressurized pressure exceeds the allowable value, the control device 3 switches the flow path to increase the flow path cross-sectional area, so that the pressurized pressure fluctuates within a certain fluctuation range but is maintained within the allowable range. Is done.

  On the other hand, when the cross-sectional area of the flow path is fixed, in order to increase the flow rate of the gas-liquid two-phase flow, it is necessary to increase the pressurization pressure by increasing the rotational speed of the pump. In order to reduce the pressure, it is necessary to lower the pressurization pressure by lowering the rotational speed of the pump.

  Thus, when the cross-sectional area of the flow path is fixed, in order to change the flow rate of the gas-liquid two-phase flow, it is necessary to change the pressurization pressure significantly. However, in this embodiment, the pressurized pressure can be controlled within an allowable range, and the pore diameter remains the same even if the flow path cross-sectional area is changed step by step. Fine bubbles can be generated.

  The lower diagram of FIG. 12 is a diagram showing the relationship between the pump power consumption and the gas-liquid two-phase flow rate. The gas-liquid two-phase flow rate is large, and no excessive pressure loss occurs in the portion where the processing amount is required. Therefore, the power consumption of the pump can be reduced.

  According to the present embodiment, when the amount of fine bubbles generated is changed, the number of rotations of the pump and the cross-sectional area of the pump are changed, so that an excessive pressure rise is suppressed by maintaining the pressurizing pressure within a range necessary for generating fine bubbles. Therefore, fine bubbles can be generated efficiently and with a stable bubble diameter distribution.

  According to the present embodiment, when changing the amount of fine bubbles generated, the number of rotations of the pump and the cross-sectional area of the narrow channel are changed, so that the pressurizing pressure is maintained within the range necessary for generating fine bubbles. It is possible to suppress an excessive increase in pressure. For this reason, fine bubbles can be generated efficiently and with a stable bubble diameter distribution.

  A third embodiment of the present invention will be described with reference to FIGS. 17 to 23 are configuration diagrams of the perforated plate unit of this embodiment.

  The perforated plate unit of the present embodiment is a modification of the perforated plate unit 4 shown in FIGS. 2 to 6 of the first embodiment.

  As shown in FIGS. 17 to 23, in the perforated plate 211, a circular plate is divided into a plurality of regions, each having a different hole diameter, and a hole having a different cross-sectional area is provided in each region. Yes. Alternatively, the hole diameter may be the same for each region in the porous plate 211 and the holes having the same cross-sectional area may be provided so that the number of holes per unit surface area is different. The flow restricting plate is provided on the front and back of the porous plate 211, the semicircular flow restricting plate 211 is provided on the front side (upstream side), and the semicircular flow restricting plate 212 is provided on the back side (downstream side). Is provided. A shaft 214 is fitted in the center of the flow path restriction plate 211 and is fixed to the shaft 214 by a fixing plate 216. A shaft 215 is fitted in the center of the flow path restriction plate 212 and is fixed to the shaft 215 by a fixing plate 217. The shaft 215 is hollow, the shaft 214 is inserted into the space of the hollow portion, and the shaft 215 and the shaft 216 are independently rotated by the driving device 7.

  The control device 3 controls the drive device 7 to rotate the shaft 215 and the shaft 216 independently, and controls the rotation angle of the front-side flow path restriction plate 211 and the rotation angle of the back-side flow restriction plate 212 to control the air flow. The location, number of holes, and channel area of the holes through which the liquid two-phase flow passes are adjusted to control the required effective number of holes or the required channel cross-sectional area. In the above description, the flow restricting plates 211 and 212 have been described as being semicircular, but the shape can be modified.

  According to the present embodiment, holes can be provided on the entire surface of the perforated plate, the cross-sectional area of the narrow channel can be changed more finely, and the amount of fine bubbles generated can be controlled smoothly. Further, since the fluctuation of the pressurizing pressure at the time of changing the flow rate is suppressed, the rapid flow rate / pressure fluctuation to the pump is alleviated, and the burden on the pump is reduced.

  A fourth embodiment of the present invention will be described with reference to FIGS. FIG. 24 is a configuration diagram of the fine bubble generating device of the present embodiment, and FIG. 25 is a control flowchart of an operation method during back-flow cleaning in the fine bubble generating device of the present embodiment.

  The fine bubble generating apparatus of the present embodiment is configured in the same manner as in the first embodiment shown in FIG. 1, but a valve 12 is installed in the flow path 9a, an inflow pipe 16 is installed in the valve 12, and the flow path A valve 13 and a valve 14 are installed between the pump 1 of 9b and the perforated plate unit 4, a valve 15 is installed in the flow path 9c, the valve 13 and the valve 15 are connected by a pipe 17, and a drain pipe is connected to the valve 14 18 is provided. Each of the valves 12, 13, 14, and 15 is configured by a three-way valve, and is connected to the control device 3 through a signal line, and switching control of opening and closing is performed by a command from the control device 3.

  During normal operation, the valve 12 opens on the flow path 9a side and closes the inflow pipe 16 side. Each of the valve 13 and the valve 15 is opened on the channel 9b side, opened on the channel 9c side, and closed on the pipe 17 side. The valve 14 opens the flow path 9b side and closes the drain pipe 18 side. As a result, the gas-liquid two-phase flow 10 is pressurized by the pump 1 to generate fine bubbles in the perforated plate unit 4 and flow out as a fine bubble flow 11.

  When the blockage of the porous plate in the porous plate unit 4 is detected due to the suspended matter in the liquid phase, the deposition / adhesion of dissolved components, etc., the control device 3 switches the valves 12 to 15 and performs the backwash operation.

  During the backwash operation, the valve 12 closes the flow path 9a side and opens the inflow pipe 16 side. Each of the valve 13 and the valve 15 is closed on the flow path 9b side, closed on the flow path 9c side, and opened on the pipe 17 side. The valve 14 closes the flow path 9b side and opens the drain pipe 18 side.

  The backwash water flowing in from the inflow pipe 16 is pressurized by the pump 1, flows through the pipe 17, flows into the perforated plate unit 4 from the flow path 9 c side, and is discharged from the drain pipe 18 after washing the holes of the perforated plate unit 4. Is done. Instead of the perforated plate unit 4, the perforated plate of Example 2 may be installed.

  Switching to the backwash operation is performed according to the flowchart shown in FIG.

  In step S <b> 11, the control device 3 activates the driving device 7 to set the effective hole number of the perforated plate unit 4 to the calibration target value mp. In step S12, the control device 3 controls the inverter 2 to start the pump 1, and controls the rotation speed of the pump 1 so that the measured value of the flow meter 6 becomes the calibration target value Qp.

  In step S13, the measured value P of the pressure gauge 5 is measured, and it is determined whether or not the difference between the measured value P and the calibration target value Pp is larger than the allowable deviation amount ΔP. When the difference between the measured value P and the calibration target value Pp is larger than the tolerance ΔP of the deviation amount, the porous plate in the porous plate unit 4 is clogged due to precipitation or adhesion of suspended matter or dissolved components in the liquid phase. Is determined, and the process proceeds to step S14.

  In step S14, the valves 12 to 15 are switched to the backwash channel. That is, as described above, the valve 12 closes the flow path 9a side, the inflow pipe 16 side opens, and the valves 13 and 15 close the flow path 9b side, close the flow path 9c side, and close the pipe 17 side, respectively. The valve 14 is opened, the flow path 9b side is closed, and the drain pipe 18 side is opened.

  In step S <b> 15, the control device 3 starts the pump 1 and operates the pump 1 for the set operation time to perform the backwashing of the perforated plate unit 4. When the set operation time has elapsed, the pump 1 is stopped, and in step S16, the open / close states of the valves 12 to 15 are switched to switch to the flow path for generating fine bubbles during normal operation, and the process returns to step S2.

  The calibration target values mp and Qp and the operation time of the pump 1 during backwashing are input from the input device 8.

  In the above description, the example in which the backwash operation is performed when the difference between the calibration target value and the measured value is larger than the allowable value has been described. However, the control device 3 performs time measurement with a timer and is input from the input device 8. The backwashing start time and the time interval for starting the backwashing are switched to the flow path for backwashing, and the pump 1 is operated for the set operation time. You may control to return to the bubble production | generation flow path.

  When the perforated plate unit 4 is used, a protruding portion or a brush-like component that contacts the perforated plate in the axial direction of the flow path restricting plate may be attached. Moreover, you may have the part processed by the acute angle with respect to the porous plate surface in the axial direction part of the flow-path restriction | limiting board. When there are a plurality of flow path restriction plates as shown in the third embodiment, this processing may be performed on the front face flow restriction plate. In this case, the flow path restriction plate may be moved to the entire movable region during the operation at a set time interval during the fine bubble generation operation or before the pump is activated during the backwash operation. An end face structure that contacts the perforated plate may be provided on the flow path restricting plate, and when the flow restricting plate moves on the surface of the perforated plate, deposits on the surface of the porous plate may be scraped off and peeled off by the end face structure. Thus, blockage of the holes of the perforated plate can be avoided.

  According to the present embodiment, since the deposits in the narrow channel can be removed, the fine bubble generating device can be prevented from being blocked and the pressurization pressure can be prevented from rising. Further, since the change in the bubble diameter distribution due to the change in the hole cross-sectional area and hole shape of the perforated plate can be avoided, the fine bubbles can be generated more efficiently and with a stable bubble diameter distribution.

  The gas dissolution efficiency of the gas-liquid two-phase flow 10 flowing into the perforated plate unit 4 affects the fine bubble number concentration of the water 11 containing fine bubbles. When the fine bubble number concentration is low, the amount of fine bubbles cannot be secured even if the flow rate of the fine bubble-containing water 11 is increased. Even if the gas injection rate of the gas-liquid two-phase flow flowing into the pump 1 is increased, if the dissolution efficiency is low, the fine bubbles cannot be fully utilized because they flow out into the fine bubble mixed water 11 as coarse bubbles.

  In the present embodiment, a method of improving the gas dissolution efficiency in the subsequent stage of the pump 1 and further increasing the fine bubble number concentration of the fine bubble-containing water 11 will be described with reference to FIG. FIG. 26 is a block diagram of the fine bubble generating apparatus of the present embodiment.

  The fine bubble generating apparatus of the present embodiment is configured in the same manner as the fine bubble generating apparatus of the first embodiment or the second embodiment, but the pressure is increased upstream of the pressure gauge 5 between the pump 1 and the perforated plate unit 4. A tank 21 is installed. The pressure tank 21 has a structure that can withstand the pressurizing pressure necessary for generating fine bubbles. The gas-liquid two-phase flow 10 pressurized by the pump 1 stays in the pressure tank 21 under a high-pressure condition, so that gas dissolution proceeds.

  According to the present embodiment, the dissolved gas concentration of the gas-liquid two-phase flow flowing into the narrow channel can be increased, and the number concentration of fine bubbles precipitated due to the reduced pressure increases, so the amount of fine bubbles generated per flow rate can be reduced. Increase more. For this reason, the utilization efficiency of the gas inject | poured before the pump improves, and it can produce | generate a fine bubble more efficiently.

  The present embodiment can be applied to any one of Embodiments 2 to 4. When the embodiment is applied to Embodiment 4, the valve 14 and the drain pipe 18 are installed in the subsequent stage of the pressure tank 21.

  When the perforated plate unit 4 is used, the gas that could not be dissolved is accumulated near the entrance of the perforated plate, and when it reaches a predetermined amount, it may pass through the perforated plate as a gas phase. In principle, gas that has not been dissolved under pressure does not become microbubbles even under reduced pressure. Therefore, coarse bubbles are periodically mixed in the water 11 containing fine bubbles flowing out of the perforated plate, and the upper gas phase. The gas utilization efficiency is reduced due to desorption.

  In the present embodiment, a method of making the coarse bubbles flowing out downstream of the perforated plate into fine bubbles by changing the inflow state of the gas-liquid two-phase flow downstream of the pump 1 will be described with reference to FIG.

  The fine bubble generating apparatus of the present embodiment is configured in the same manner as the fine bubble generating apparatus of the first or second embodiment, but a fluid control plate 22 is installed between the pump 1 and the perforated plate unit 4. . The fluid control plate 22 turns the gas-liquid two-phase flow pressurized by the pump 1 and increases the gas phase ratio in the vicinity of the center in the pipe cross-sectional direction when flowing into the perforated plate unit 4. When the hole positions of the perforated plate unit 4 are provided near the center and near the periphery, the gas-liquid two-phase flow with a high gas phase ratio flowing out from the center and a relatively low flow rate has a relatively high liquid phase ratio flowing out from the periphery. A shearing force is applied by a high-speed two-phase flow. As a result, when coarse bubbles are mixed in the gas-liquid two-phase flow flowing out from the center, the coarse bubbles are refined by this shearing force.

  The present embodiment can be applied to any one of Embodiments 2 to 4. When the embodiment is applied to Embodiment 4, the valve 14 and the drain pipe 18 are installed in the subsequent stage of the fluid control plate 22.

  According to the present embodiment, the gas-liquid two-phase flow flowing into the perforated plate unit 4 is divided into portions having different gas phase ratios, and a shearing force is generated between these gas-liquid two-phase flows at the subsequent stage of the perforated plate. As a result, even if coarse bubbles that cannot be made into microbubbles even if the pressure is reduced to the perforated plate, the microbubbles are mechanically made after flowing out of the perforated plate, so the efficiency of using the gas injected in the previous stage of the pump is improved. To do. As a result, fine bubbles can be generated more efficiently.

BRIEF DESCRIPTION OF THE DRAWINGS The block diagram of the fine bubble production | generation apparatus which is Example 1 of this invention. The top view which shows the structure of the perforated panel unit of a present Example. The longitudinal cross-sectional view which shows the structure of the perforated panel unit of a present Example. The top view of the perforated panel of a present Example. The top view of the flow-path restriction | limiting board of a present Example. The top view which shows the structure of the perforated panel unit of a present Example. The longitudinal cross-sectional view which shows the structure of the narrow channel of a present Example. The longitudinal cross-sectional view which shows the structure of the narrow channel of a present Example. The top view which shows the structure of the narrow flow path of a present Example. The top view which shows the structure of the narrow flow path of a present Example. The control flowchart figure of a present Example. The figure explaining the effect | action and effect of a present Example. The block diagram of the fine bubble production | generation apparatus which is Example 2 of this invention. The top view of the perforated panel of a present Example. The top view of the perforated panel of a present Example. The figure explaining the effect | action and effect of a present Example. The top view which shows the structure of the perforated plate unit of the microbubble production | generation apparatus which is Example 3 of this invention. The longitudinal cross-sectional view which shows the structure of the perforated panel unit of a present Example. The top view of the perforated panel of a present Example. The top view of the flow-path restriction | limiting board of a present Example. The top view which shows the structure of the perforated panel unit of a present Example. The top view of the flow-path restriction | limiting board of a present Example. The top view of the flow-path restriction | limiting board of a present Example. The block diagram of the fine bubble production | generation apparatus which is Example 4 of this invention. The control flowchart figure by a present Example. The block diagram of the microbubble production | generation apparatus which is Example 5 of this invention. The block diagram of the microbubble production | generation apparatus which is Example 6 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Pump, 2 ... Inverter, 3 ... Control apparatus, 4 ... Perforated board unit, 5 ... Pressure gauge, 6 ...
Flow meter, 7 ... Drive device, 8 ... Input device, 9 ... Flow path, 12, 13, 14, 15 ... Valve, 16 ...
Inflow pipe, 17 ... pipe, 18 ... drain pipe, 21 ... pressure tank, 22 ... fluid control plate, 100 ... perforated plate, 101 ... channel restriction plate, 102 ... shaft, 103 ... hole, 104 ... fixing plate.

Claims (8)

  A pump connected to the gas-liquid two-phase flow generator, an inverter for controlling the number of revolutions of the pump, a plurality of flow paths branched at the subsequent stage of the pump, and a valve in each of the plurality of flow paths And a perforated plate unit having a fixed flow path cross-sectional area connected thereto, and a control device for controlling the opening and closing of the inverter and the valve, provided by the control device for each of the plurality of branch flow paths. A fine bubble generating apparatus that selectively opens and closes the valve. The flow path cross-sectional area is more than the same diameter of the hole, the hole generation device microbubble of claim 1 which is formed in one of slit bets shape Tsu communication. 2. The fine structure according to claim 1, wherein the flow path cross-sectional area is formed of a plurality of holes having the same diameter, and the number of holes of at least some of the porous plate units is different from the number of holes of other porous plate units. Bubble generator.   The apparatus for generating fine bubbles according to any one of claims 1 to 3, wherein a pressure tank or a fluid control plate is installed in a flow path between the pump and the porous plate unit. One three-way valve is provided at the front stage of the pump, two at the downstream stage of the pump at the rear stage of the pump, and one at the rear stage of the perforated plate unit, and backwash water is supplied when the three-way valve is switched. The microbubble generating device according to any one of claims 1 to 3, wherein a pipe connected to a three-way valve is connected so as to flow from the downstream side to the upstream side of the perforated plate unit. In an inverter that controls the number of revolutions of a pump connected to a gas-liquid two-phase flow generator and a controller that controls opening and closing of a valve, the target value of the fine bubble generation amount is determined from the input target value of the fine bubble generation amount. And the discharge flow rate of the fine bubble-containing water by the ratio of the fine bubble content rate calculated from the set or set pressure, and the measured flow rate of the calculated discharge flow rate and the gas-liquid two-phase flow comparing the case from the discharge flow rate measurement values are computed for the large decrease the pump speed by the inverter, the case from the discharge flow rate measurement values are computed for the small pump rotational speed by the inverter And a plurality of flow paths branched at the subsequent stage of the pump and connected to each of the plurality of flow paths with valves so that the deviation between the set pressure value and the measured pressure value is within an allowable value. Fixed Selectively opening and closing control and the method of generating the micro-bubbles for reducing increase in the valve channel cross-sectional area of the perforated plate unit having a flow path cross-sectional area of several or numbers slits. In an inverter that controls the number of revolutions of a pump connected to a gas-liquid two-phase flow generator and a controller that controls opening and closing of a valve, the target value of the fine bubble generation amount is determined from the input target value of the fine bubble generation amount. And the discharge flow rate of the fine bubble-containing water by the ratio of the fine bubble content rate calculated from the set or set pressure, and the measured flow rate of the calculated discharge flow rate and the gas-liquid two-phase flow comparing, each from the discharge flow rate the flow rate measurement value is calculated with the case of a large decrease of the pump speed by the inverter, a plurality of flow paths branching at a later stage of the pump, the plurality of flow path The flow passage cross-sectional area of a perforated plate unit having a fixed flow passage cross-sectional area with a number of holes or slits connected with a valve is reduced by selectively opening and closing the valve, and the pressure is set to a set value. To keep the above Together if from the discharge flow amount measured value is calculated for small increase pump speed by the inverter, pressure flow path cross-sectional area of the plurality of perforated plate unit is increased by selectively controlling opening and closing said valve Is maintained at the set value, and the fine bubble generation method is controlled to the target fine bubble generation amount. In an inverter that controls the number of revolutions of a pump connected to a gas-liquid two-phase flow generator and a controller that controls opening and closing of a valve, the target value of the fine bubble generation amount is determined from the input target value of the fine bubble generation amount. And the discharge flow rate of the fine bubble-containing water by the ratio of the fine bubble content rate calculated from the set or set pressure, and the measured flow rate of the calculated discharge flow rate and the gas-liquid two-phase flow If the measured flow rate is greater than the calculated flow rate, a plurality of flow paths branched at a later stage of the pump and a fixed connection connected to each of the plurality of flow paths with valves. If the flow passage cross-sectional area of the perforated plate unit having a flow passage cross-sectional area having a number of holes or slits is decreased by selectively opening and closing the valve, and the flow rate measurement value is smaller than the calculated discharge flow rate, The valve cross-sectional area of the plurality of perforated plate units Increases in selectively opening and closing control, increase or decrease the pump speed by the inverter, so as to maintain the pressure to the set value, fine bubble generation method of controlling the fine bubbles generated amount of target.

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