JP2014104441A - Fine bubble generating nozzle and fine bubble generating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate fine bubbles stably.SOLUTION: A fine bubble generating nozzle 2 includes a first taper part 212, a first throat part 213, a first enlarged part 221, a second taper part 222, a second throat part 223, a second enlarged part 231, a third taper part 232, a third throat part 233, and a third enlarged part 234, which are arranged in series from the upstream side of a nozzle flow passage 20. A pressurized liquid into which gas is pressurized-dissolved is accelerated at the first taper part 212, and is jetted from the first throat part 213 to the first enlarged part 221. Therefore, gas dissolved in the pressurized liquid is precipitated in the liquid as fine bubbles, and the fine bubbles are made further finer. The fine bubble containing liquid is accelerated at the second taper part 222, is jetted from the second throat part 223 to the second enlarged part 231, is accelerated at the third taper part 232, and is jetted from the third throat part 233 to the third enlarged part 234. Therefore, fine bubbles are made further finer. As a result, it is possible to generate fine bubbles stably in a large quantity.

Description

  The present invention relates to a fine bubble generation nozzle that generates a liquid containing fine bubbles from a pressurized liquid in which a gas is dissolved under pressure, and a fine bubble generation device including the fine bubble generation nozzle.

  In recent years, liquids containing fine bubbles having a diameter of 1 mm or less have been used in various fields, and various apparatuses for generating fine bubbles in liquids have been proposed. For example, in the fine bubble generator of Patent Document 1, a mixed fluid in which a gas and a liquid are mixed is swirled at high speed in a fluid swirl chamber, and the bubbles are refined by a shearing force generated in the swirl flow. The refined bubbles are supplied together with the liquid.

  Moreover, in the gas-liquid dissolution mixing apparatus of patent document 2, the mixed fluid which flows through a pipe line is ejected from the nozzle part by which the several nozzle hole was provided in the end surface, after passing through the redistributor which has a venturi pipe. In the redistributor, liquid and air bubbles gathered at the top of the conduit are accelerated at the throat of the venturi. Further, the liquid and the bubbles are mixed in the duct of the nozzle portion and then ejected from the plurality of nozzle holes in a state where the bubbles are distributed in the liquid. Since the nozzle hole is smaller than the duct, the liquid passing through the nozzle hole is accelerated and the static pressure is lowered. For this reason, the gas melt | dissolved in the liquid precipitates as a microbubble. In addition, bubbles that are not dissolved in the liquid are also subdivided due to, for example, turbulence in the flow when accelerated by the nozzle holes.

Japanese Patent No. 4129290 Japanese Patent Publication No. 6-93991

  By the way, in recent years, a liquid containing fine bubbles (so-called nanobubbles) having a diameter of less than 1 μm has been attracting attention in various fields. A large amount of fine bubbles can be stably generated, and a liquid containing fine bubbles can be supplied at various flow rates. The technology to supply with

  However, in the apparatus of Patent Document 1, the structure for generating the swirl flow is complicated and there are many design parameters. Therefore, when the supply flow rate is changed, a long time is required for the design for stably generating fine bubbles. Moreover, when increasing a supply flow rate, the force added to the nozzle for supplying a bubble and a liquid to a water tank etc. will become large. In order to reduce the force applied to the nozzle, it is conceivable to distribute the generated bubbles to a plurality of nozzles. However, in the apparatus of Patent Document 1, the generated bubbles are biased to one side even if the apparatus is slightly inclined. Therefore, the bubbles cannot be supplied uniformly and stably by the plurality of nozzles.

  This invention is made | formed in view of the said subject, and aims at producing | generating a fine bubble stably.

  The invention according to claim 1 is a fine bubble generating nozzle for generating a liquid containing fine bubbles from a pressurized liquid obtained by pressure-dissolving a gas, and from upstream to downstream of a nozzle channel to which the pressurized liquid is supplied. An upstream tapered portion in which the flow area gradually decreases toward the upstream, a downstream end of the upstream tapered portion, an upstream throat portion for ejecting fluid from the upstream tapered portion from the upstream outlet, and the upstream outlet Connected to the enlarged portion for expanding the flow area, connected to the downstream end of the enlarged portion, connected to the downstream tapered portion where the flow area gradually decreases from upstream to downstream, and connected to the downstream end of the downstream tapered portion And a downstream throat portion that ejects the fluid from the downstream taper portion from the downstream ejection port.

  The invention according to claim 2 is the fine bubble generating nozzle according to claim 1, wherein the inner surface of the upstream taper portion and the inner surface of the downstream taper portion are respectively centered on the central axis of the nozzle flow path. The angle formed by the inner surface of the upstream taper portion and the angle formed by the inner surface of the downstream taper portion are each 90 ° or less in a cross section that is a part of a conical surface and includes the central axis.

  The invention according to claim 3 is the fine bubble generating nozzle according to claim 1 or 2, wherein the length of the upstream throat is 1.1 to 10 times the diameter of the upstream throat. Yes, the length of the downstream throat is 1.1 to 10 times the diameter of the downstream throat.

  A fourth aspect of the present invention is the fine bubble generating nozzle according to any one of the first to third aspects, wherein the diameter of the downstream throat is equal to or larger than the diameter of the upstream throat.

  The invention according to claim 5 is the fine bubble generating nozzle according to any one of claims 1 to 4, and spreads from the upstream outlet of the enlarged portion in a cross section including a central axis of the nozzle flow path. The angle formed by the surface and the central axis is not less than 45 ° and not more than 90 °.

  A sixth aspect of the present invention is the fine bubble generating nozzle according to any one of the first to fifth aspects, wherein another nozzle flow path having the same structure as the nozzle flow path, and a pressurized liquid The apparatus further includes a branching portion that branches into the nozzle channel and the another nozzle channel.

  A seventh aspect of the invention is a fine bubble generating device, wherein the fine bubble generating nozzle according to any one of the first to sixth aspects, and a pressure generating liquid that is supplied to the fine bubble generating nozzle. A pressure fluid generating unit.

  The invention described in claim 8 is the micro-bubble generating device according to claim 7, wherein the pressurizing liquid channel connecting the pressurizing liquid generating section and the microbubble generating nozzle, and the pressurizing liquid An adjustment valve provided in the flow path for adjusting the pressure of the pressurized liquid in the pressurized liquid flow path, a pressure sensor for measuring the pressure in the pressurized liquid generating section, and an output from the pressure sensor A valve control unit for controlling the regulating valve.

  A ninth aspect of the invention is a fine bubble generating device, wherein the fine bubble generating nozzle according to any one of the first to sixth aspects is added to the pressure generating liquid that is supplied to the fine bubble generating nozzle. A pressure liquid generating section; and a storage section for storing a target liquid to which the liquid generated by the fine bubble generating nozzle is supplied. It is a downstream jet port, and a hole is provided on the inner surface of the reservoir portion that is recessed toward the outside and connected to the downstream jet port so as to expand a flow passage area from the downstream jet port to the inner surface.

  In the present invention, fine bubbles can be stably generated.

It is sectional drawing of the microbubble production | generation apparatus which concerns on 1st Embodiment. It is an expanded sectional view of a mixing nozzle. It is an expanded sectional view of a fine bubble production nozzle. It is an expanded sectional view of a fine bubble production nozzle. It is an expanded sectional view of another fine bubble production | generation nozzle. It is a figure which shows the relationship between the distance between throat parts and the density of a fine bubble. It is sectional drawing of the fine bubble production | generation nozzle which concerns on 2nd Embodiment. It is sectional drawing of the microbubble production | generation apparatus which concerns on 3rd Embodiment. It is sectional drawing of a horizontal flow path. It is a figure which expands and shows a dam part. It is a figure which shows the relationship between the height of a liquid level, and the increase rate of a gas-liquid contact area. It is a figure which expands and shows another dam part. It is sectional drawing which shows another dissolution flow path part. It is sectional drawing of the microbubble production | generation apparatus which concerns on 4th Embodiment. It is sectional drawing of the fine bubble production | generation nozzle which concerns on 5th Embodiment. It is the figure which looked at the fine bubble production | generation nozzle from the front end side. It is sectional drawing of the fine bubble production | generation nozzle which concerns on 6th Embodiment. It is the figure which looked at the fine bubble production | generation nozzle from the front end side.

  FIG. 1 is a cross-sectional view showing a microbubble generator 1 according to a first embodiment of the present invention. The fine bubble generating device 1 includes a fine bubble generating nozzle 2, a pressurized liquid generating unit 3, a pressurized liquid flow path 4, and a storage unit 5. The pressurized liquid channel 4 connects the pressurized liquid generating unit 3 and the fine bubble generating nozzle 2. The tip of the fine bubble generating nozzle 2 is connected to the side wall 51 of the reservoir 5. The storage unit 5 stores the target liquid 91. The pressurizing liquid generating unit 3 generates a pressurizing liquid 71 obtained by pressurizing and dissolving a gas in the liquid, and supplies the pressurizing liquid 71 to the fine bubble generating nozzle 2 through the pressurizing liquid channel 4. The fine bubble generation nozzle 2 generates a liquid containing fine bubbles (hereinafter, referred to as “fine bubble-containing liquid 73”) from the pressurized liquid 71, and the fine bubble-containing liquid 73 is added to the target liquid 91 stored in the storage unit 5. Supply.

  In the fine bubble generating device 1 according to the present embodiment, the pressurized liquid generating unit 3 generates a pressurized liquid 71 in which air is dissolved under pressure. Further, the fine bubble generating nozzle 2 generates a fine bubble-containing liquid 73 that is water including fine air bubbles (so-called nanobubbles) having a diameter of less than 1 μm, and is supplied into the target liquid 91 that is water. In FIG. 1, in order to facilitate understanding of the drawing, fluids such as the pressurized liquid 71 and the target liquid 91 are indicated by a diagonal line with broken lines (the same applies to the following similar drawings). In the fine bubble generating device 1, a pressurized liquid 71 obtained by dissolving various types of gas in various types of liquid under pressure may be used.

  The pressurized liquid generating unit 3 includes a mixing nozzle 31, a dissolution channel unit 32, and a pump 33. In the pressurized liquid generating unit 3, the liquid (water in the present embodiment) pumped to the mixing nozzle 31 by the pump 33 and the gas (air in the present embodiment) sucked from the outside are mixed into the mixing nozzle. 31 is mixed and ejected into the dissolution channel portion 32. The inside of the dissolution channel portion 32 is pressurized and is in a state where the pressure is higher than the atmospheric pressure (hereinafter referred to as “pressurized environment”), and the liquid and gas ejected from the mixing nozzle 31 are mixed. While a fluid (hereinafter referred to as “mixed fluid 72”) flows in the dissolution flow path section 32 in a pressurized environment, the gas is pressurized and dissolved in the liquid to generate the pressurized liquid 71.

  FIG. 2 is an enlarged cross-sectional view of the mixing nozzle 31. The mixing nozzle 31 mixes the liquid inlet 311 into which the liquid pumped by the pump 33 flows in, the gas inlet 319 into which gas flows, the liquid flowing in from the liquid inlet 311 and the gas flowing in from the gas inlet 319. And a mixed fluid ejection port 312 for ejecting the mixed fluid 72 (see FIG. 1). The liquid inlet 311, the gas inlet 319, and the mixed fluid outlet 312 are each substantially circular.

  The flow path cross section of the nozzle flow path 310 from the liquid inlet 311 to the mixed fluid outlet 312 and the flow path cross section of the gas flow path 3191 from the gas inlet 319 to the nozzle flow path 310 are also substantially circular. The channel cross section means a cross section perpendicular to the central axis of the flow path such as the nozzle flow path 310 and the gas flow path 3191, that is, a cross section perpendicular to the flow of fluid flowing through the flow path. In the following description, the area of the channel cross section is referred to as “channel area”. The nozzle flow path 310 is a Venturi tube having a flow path area that becomes smaller in the middle of the flow path.

  The mixing nozzle 31 includes an introduction portion 313, a first taper portion 314, a throat portion 315, a gas mixing portion 316, and a second portion that are continuously arranged in order from the liquid inlet 311 toward the mixed fluid outlet 312. A tapered portion 317 and a lead-out portion 318 are provided. The mixing nozzle 31 also includes a gas supply unit 3192 in which a gas flow path 3191 is provided.

  In the introduction part 313, the flow path area is substantially constant at each position in the direction of the central axis J1 of the nozzle flow path 310. In the first taper portion 314, the flow path area gradually decreases in the liquid flow direction (that is, toward the downstream side). In the throat 315, the flow path area is substantially constant. The channel area of the throat 315 is the smallest in the nozzle channel 310. In the nozzle channel 310, even if the channel area slightly changes in the throat 315, the entire portion having the smallest channel area is regarded as the throat 315. In the gas mixing unit 316, the flow channel area is substantially constant and is slightly larger than the flow channel area of the throat 315. In the second taper portion 317, the flow path area gradually increases toward the downstream side. In the derivation unit 318, the flow path area is substantially constant. The channel area of the gas channel 3191 is also substantially constant, and the gas channel 3191 is connected to the gas mixing unit 316 of the nozzle channel 310.

  In the mixing nozzle 31, the liquid that has flowed into the nozzle channel 310 from the liquid inlet 311 is accelerated by the throat portion 315 and the static pressure is lowered, and the pressure in the nozzle channel 310 is reduced in the throat portion 315 and the gas mixing portion 316. Becomes lower than atmospheric pressure. Thereby, gas is attracted | sucked from the gas inflow port 319, passes the gas flow path 3191, flows in into the gas mixing part 316, is mixed with the liquid, and the mixed fluid 72 (refer FIG. 1) is produced | generated. The mixed fluid 72 is decelerated at the second tapered portion 317 and the outlet portion 318 to increase the static pressure, and is ejected into the dissolution channel portion 32 via the mixed fluid ejection port 312.

  As shown in FIG. 1, the dissolution channel section 32 includes a first horizontal channel 321, a second horizontal channel 322, a third horizontal channel 323, and a fourth horizontal channel 324 that are stacked in the vertical direction. And a fifth horizontal flow path 325. In the following description, when the first horizontal flow path 321, the second horizontal flow path 322, the third horizontal flow path 323, the fourth horizontal flow path 324, and the fifth horizontal flow path 325 are collectively indicated, “horizontal flow path 321”. ~ 325 ". The horizontal flow paths 321 to 325 are parts that form an internal space through which liquid flows. The horizontal flow paths 321 to 325 are pipelines extending in the horizontal direction, and the cross section perpendicular to the longitudinal direction of the horizontal flow paths 321 to 325 is substantially rectangular. In the present embodiment, the width of the horizontal flow paths 321 to 325 is about 40 mm.

  The mixing nozzle 31 is attached to the upstream end of the first horizontal flow path 321 (that is, the left end in FIG. 1), and the mixed fluid 72 after being ejected from the mixing nozzle 31 is It flows toward the right side in FIG. 1 under a pressurized environment. In the present embodiment, the mixed fluid 72 immediately after being ejected from the mixing nozzle 31 is ejected from above the liquid level of the mixed fluid 72 in the first horizontal flow path 321, and is downstream of the first horizontal flow path 321. It collides directly with the liquid surface before colliding with the wall surface (that is, the right wall surface in FIG. 1). In order to cause the mixed fluid 72 ejected from the mixing nozzle 31 to directly collide with the liquid surface, the length of the first horizontal flow path 321 is set to the center of the mixed fluid ejection port 312 (see FIG. 2) of the mixing nozzle 31. It is preferable to make it larger than 7.5 times the vertical distance between the lower surface of one horizontal flow path 321.

  In the pressurized liquid generating unit 3, a part or the whole of the mixed fluid ejection port 312 of the mixing nozzle 31 may be located below the liquid level of the mixed fluid 72 in the first horizontal flow path 321. As a result, the mixed fluid 72 immediately after being ejected from the mixing nozzle 31 directly collides with the mixed fluid 72 flowing in the first horizontal flow channel 321 in the first horizontal flow channel 321 as described above.

  A substantially circular opening 321 a is provided on the lower surface of the downstream end portion of the first horizontal flow path 321, and the mixed fluid 72 flowing through the first horizontal flow path 321 is located below the first horizontal flow path 321. It falls to the 2nd horizontal flow path 322 located through the opening 321a. The fluid flowing through the horizontal flow paths 321 to 325 is not necessarily in a gas-liquid mixed state, but is simply referred to as “mixed fluid 72” (the same applies to other embodiments). . In the second horizontal flow path 322, the mixed fluid 72 that has dropped from the first horizontal flow path 321 flows from the right side to the left side in FIG. 1 in a pressurized environment, and the downstream end of the second horizontal flow path 322. It falls to the 3rd horizontal flow path 323 located under the 2nd horizontal flow path 322 through the substantially circular opening 322a provided in the lower surface. In the third horizontal flow path 323, the mixed fluid 72 dropped from the second horizontal flow path 322 flows from the left side to the right side in FIG. It drops to a fourth horizontal flow path 324 located below the third horizontal flow path 323 through a substantially circular opening 323a provided on the lower surface of the first horizontal flow path. As shown in FIG. 1, in the first horizontal flow path 321 to the fourth horizontal flow path 324, the mixed fluid 72 is divided into a liquid layer containing bubbles and a gas layer located thereabove.

  In the fourth horizontal flow path 324, the mixed fluid 72 that has dropped from the third horizontal flow path 323 flows from the right side to the left side in FIG. 1 in a pressurized environment, and the downstream end of the fourth horizontal flow path 324. It flows into the fifth horizontal flow path 325 located below the fourth horizontal flow path 324 (that is, falls) through a substantially circular opening 324a provided on the lower surface of the first horizontal flow path. In the fifth horizontal flow path 325, unlike the first horizontal flow path 321 to the fourth horizontal flow path 324, there is no gas layer, and in the liquid filling the fifth horizontal flow path 325, The air bubbles are slightly present in the vicinity of the upper surface of the five horizontal flow paths 325. In the fifth horizontal flow path 325, the mixed fluid 72 flowing in from the fourth horizontal flow path 324 flows from the left side to the right side in FIG.

  In the pressurization liquid production | generation part 3, the horizontal flow paths 321-325 of the dissolution flow path part 32 flow down from the top to the bottom, repeating steps gradually (that is, the flow in the horizontal direction and the flow in the downward direction). In the mixed fluid 72 (flowing alternately and repeatedly), the gas is gradually dissolved in the liquid under pressure. In the fifth horizontal flow path 325, the concentration of the gas dissolved in the liquid is substantially equal to 60% to 90% of the (saturated) solubility of the gas under a pressurized environment. And the excess gas which did not melt | dissolve in the liquid exists in the 5th horizontal flow path 325 as a bubble of the magnitude | size which can be visually recognized. Since the direction of the flow of the mixed fluid 72 in the horizontal channels 321 to 325 adjacent to each other in the vertical direction is reversed, the pressurized liquid generating unit 3 can be reduced in size.

  The dissolution channel part 32 further includes an excess gas separation part 326 extending upward from the upper surface on the downstream side of the fifth horizontal channel 325, and the excess gas separation part 326 is filled with the mixed fluid 72. The cross section perpendicular to the vertical direction of the surplus gas separation part 326 is substantially rectangular, and the upper end of the surplus gas separation part 326 is opened to the atmosphere via a pressure adjustment throttle part 327. The bubbles of the mixed fluid 72 flowing through the fifth horizontal flow path 325 rise in the surplus gas separation unit 326 and are released into the atmosphere.

  In this manner, the excess gas is separated from the mixed fluid 72, whereby the pressurized liquid 71 that does not substantially include bubbles of a size that can be easily visually recognized is generated, and is downstream of the fifth horizontal channel 325. Is sent to the pressurized liquid flow path 4 connected to the end of this (that is, the right end in FIG. 1). In the present embodiment, the pressurized liquid 71 dissolves a gas that is about twice or more the gas (saturated) solubility under atmospheric pressure. The liquid of the mixed fluid 72 flowing through the horizontal flow paths 321 to 325 in the dissolution flow path section 32 can also be regarded as the pressurized liquid 71 in the process of generation.

  The fine bubble generating device 1 further includes a regulating valve 61, a pressure sensor 62, and a valve control unit 63. The adjustment valve 61 is provided in the pressurizing fluid channel 4 and adjusts the pressure of the pressurizing fluid 71 in the pressurizing fluid channel 4. The pressure sensor 62 is disposed above the first horizontal flow path 321 and measures the pressure in the dissolution flow path section 32 of the pressurized liquid generating section 3. An exhaust valve 64 is also provided above the first horizontal flow path 321. In the microbubble generator 1, the measured value of the pressure in the dissolution flow path portion 32 output from the pressure sensor 62 is a predetermined pressure (preferably, 0.1 MPa to 0.45 MPa). The regulating valve 61 is controlled by the valve control unit 63. In other words, the valve control unit 63 controls the adjustment valve 61 based on the output from the pressure sensor 62. Thereby, even if the viscosity of the mixed fluid 72 changes due to a temperature change, the pressure change in the dissolution channel portion 32 is reduced. The adjusting valve 61 may be manually operated. The pressurizing liquid 71 guided from the dissolution channel portion 32 to the pressurizing liquid channel 4 flows into the fine bubble generating nozzle 2.

  FIG. 3 is an enlarged sectional view showing the fine bubble generating nozzle 2. The fine bubble generating nozzle 2 includes a substantially cylindrical first nozzle portion 21, a second nozzle portion 22, and a third nozzle portion 23, which are directed from the pressurized liquid flow path 4 toward the storage portion 5 (that is, from upstream). It is formed by connecting in order (downstream). The upstream end portion of the first nozzle portion 21 is an attachment portion 219 that is attached to the downstream end portion of the pressurized liquid channel 4. The downstream end of the attachment portion 219 becomes a nozzle inlet 201 into which the pressurized liquid 71 flows from the pressurized liquid channel 4. The downstream end of the third nozzle portion 23 is a nozzle outlet 202 that opens toward the target liquid 91 (see FIG. 1) in the reservoir 5. The nozzle inlet 201 and the nozzle outlet 202 are each substantially circular. The cross section of the nozzle flow path 20 from the nozzle inlet 201 to the nozzle outlet 202 (that is, the cross section perpendicular to the central axis J2 of the nozzle flow path 20) is also substantially circular.

  The fine bubble generating nozzle 2 includes an introduction portion 211, a first taper portion 212, a first throat portion 213, a first expansion portion 221, and a second taper portion 222 that are sequentially continuous from the upstream side of the nozzle flow path 20. The second throat portion 223, the second enlarged portion 231, the third tapered portion 232, the third throat portion 233, and the third enlarged portion 234 are provided. The introduction part 211, the first taper part 212, and the first throat part 213 are formed in the first nozzle part 21. The first enlarged portion 221, the second tapered portion 222, and the second throat portion 223 are formed in the second nozzle portion 22. The second enlarged portion 231, the third tapered portion 232, the third throat portion 233, and the third enlarged portion 234 are formed in the third nozzle portion 23.

  The inner surface of the introduction part 211 is a substantially cylindrical surface centering on the central axis J2 of the nozzle flow path 20, and the flow path area of the introduction part 211 is substantially constant. The first taper part 212 is connected to the downstream end of the introduction part 211. The flow path cross section at the upstream end of the first tapered portion 212 matches the flow path cross section at the downstream end of the introduction section 211. The inner surface of the first tapered portion 212 is a part of a substantially conical surface with the central axis J2 as the center. The flow path area of the first taper portion 212 gradually decreases from the upstream to the downstream of the nozzle flow path 20 (that is, toward the direction in which the pressurized liquid 71 flows). In the cross section including the central axis J2, the angle α1 formed by the inner surface of the first tapered portion 212 is preferably 10 ° or more and 90 ° or less.

  The first throat part 213 is connected to the downstream end of the first taper part 212. The flow path cross section at the upstream end of the first throat 213 matches the flow path cross section at the downstream end of the first taper section 212. The inner surface of the first throat 213 is a substantially cylindrical surface centered on the central axis J2, and the flow path area of the first throat 213 is substantially constant. The flow path area of the first throat portion 213 is the smallest in the first nozzle portion 21. The length of the first throat 213 in the axial direction toward the central axis J2 is preferably 1.1 times or more and 10 times or less the diameter of the flow path cross section of the first throat 213, more preferably 1. It is 5 times or more and 2 times or less. In the following description, the length of the channel in the axial direction is simply referred to as “length”, and the diameter of the channel cross section is simply referred to as “diameter”. The opening at the downstream end of the first throat portion 213 is a first ejection port 217 that ejects the fluid flowing from the first taper portion 212 to the first throat portion 213 as a jet flow downstream. Even if the flow path area slightly changes in the first throat portion 213, the entire portion of the first nozzle portion 21 having the smallest flow path area is regarded as the first throat portion 213.

  The first enlarged portion 221 is connected to the first jet port 217 of the first throat portion 213 and enlarges the flow path area from the first throat portion 213. The inner surface of the first enlarged portion 221 has a substantially annular first surface 221a extending from the edge of the first ejection port 217 to the radially outer side (that is, the radially outer side centered on the central axis J2), and the first surface. It has the substantially cylindrical 2nd surface 221b extended in parallel with the central axis J2 toward the downstream from the outer periphery of 221a. In the cross section including the central axis J2, the angle β1 formed by the first surface 221a of the first enlarged portion 221 and the central axis J2 is preferably 45 ° or more and 90 ° or less. In the present embodiment, the angle β1 formed by the first surface 221a of the first enlarged portion 221 and the central axis J2 is 90 °. In other words, the channel cross section at the upstream end of the first enlarged portion 221 is larger than the first jet outlet 217 of the first throat 213, and the outer peripheral edge of the channel cross section is from the edge of the first jet outlet 217. It is spaced around radially outward and is located around the first jet outlet 217.

  The second tapered portion 222 is connected to the downstream end of the first enlarged portion 221. The flow path cross section at the upstream end of the second taper portion 222 matches the flow path cross section at the downstream end of the first enlarged portion 221. The inner surface of the second taper portion 222 is a part of a substantially conical surface with the central axis J2 as the center. The flow path area of the second taper portion 222 gradually decreases from upstream to downstream. In the cross section including the central axis J2, the angle α2 formed by the inner surface of the second tapered portion 222 is preferably 10 ° or more and 90 ° or less.

  The second throat portion 223 is connected to the downstream end of the second taper portion 222. The flow path cross section at the upstream end of the second throat 223 matches the flow path cross section at the downstream end of the second taper section 222. The inner surface of the second throat 223 is a substantially cylindrical surface centered on the central axis J2, and the flow path area of the second throat 223 is substantially constant. The flow path area of the second throat portion 223 is the smallest in the second nozzle portion 22. The length of the second throat 223 is preferably 1.1 to 10 times the diameter of the second throat 223, and more preferably 1.5 to 2 times. The opening at the downstream end of the second throat portion 223 is a second ejection port 227 that ejects the fluid flowing from the second taper portion 222 to the second throat portion 223 as a jet flow downstream. Even when the flow path area slightly changes in the second throat portion 223, the entire portion of the second nozzle portion 22 having the smallest flow path area is regarded as the second throat portion 223.

  The second enlarged portion 231 is connected to the second jet outlet 227 of the second throat portion 223 and enlarges the flow path area from the second throat portion 223. The inner surface of the second enlarged portion 231 is parallel to the central axis J2 from the outer peripheral edge of the first surface 231a toward the downstream side, and a substantially annular first surface 231a extending radially outward from the edge of the second ejection port 227. And a substantially cylindrical second surface 231b. In the cross section including the central axis J2, the angle β2 formed by the first surface 231a of the second enlarged portion 231 and the central axis J2 is preferably 45 ° or more and 90 ° or less. In the present embodiment, the angle β2 formed by the first surface 231a of the second enlarged portion 231 and the central axis J2 is 90 °. In other words, the channel cross section at the upstream end of the second enlarged portion 231 is larger than the second jet outlet 227 of the second throat 223, and the outer peripheral edge of the channel cross section is from the edge of the second jet outlet 227. It is spaced from the outside in the radial direction and is located around the second ejection port 227.

  The third tapered portion 232 is connected to the downstream end of the second enlarged portion 231. The flow path cross section at the upstream end of the third tapered portion 232 matches the flow path cross section at the downstream end of the second enlarged portion 231. The inner surface of the third taper portion 232 is a part of a substantially conical surface with the central axis J2 as the center. The flow path area of the third taper portion 232 gradually decreases from upstream to downstream. In the cross section including the central axis J2, the angle α3 formed by the inner surface of the third taper portion 232 is preferably 10 ° or more and 90 ° or less.

  The third throat portion 233 is connected to the downstream end of the third taper portion 232. The flow path cross section at the upstream end of the third throat 233 coincides with the flow path cross section at the downstream end of the third taper part 232. The inner surface of the third throat 233 is a substantially cylindrical surface centered on the central axis J2, and the flow path area of the third throat 233 is substantially constant. The flow path area of the third throat portion 233 is the smallest in the third nozzle portion 23. The length of the third throat 233 is preferably 1.1 to 10 times the diameter of the third throat 233, and more preferably 1.5 to 2 times. The opening at the downstream end of the third throat portion 233 is a third outlet 237 that ejects the fluid flowing from the third taper portion 232 to the third throat portion 233 as a jet flow downstream. Even when the flow path area slightly changes in the third throat portion 233, the entire portion of the third nozzle portion 23 having the smallest flow path area is regarded as the third throat portion 233. Preferably, the diameter of the third throat 233 is equal to or greater than the diameter of the second throat 223, and the diameter of the second throat 223 is equal to or greater than the diameter of the first throat 213.

  The third enlarged portion 234 is connected to the third outlet 237 of the third throat portion 233 and enlarges the flow path area from the third throat portion 233. The downstream end of the third enlarged portion 234 is the nozzle outlet 202. The inner surface of the third enlarged portion 234 is parallel to the central axis J2 from the outer peripheral edge of the first surface 234a toward the downstream side, and a substantially annular first surface 234a that extends radially outward from the edge of the third ejection port 237. And a substantially cylindrical second surface 234b. In the cross section including the central axis J2, the angle β3 formed by the first surface 234a of the third enlarged portion 234 and the central axis J2 is preferably 45 ° or more and 90 ° or less. In the present embodiment, the angle β3 formed by the first surface 234a of the third enlarged portion 234 and the central axis J2 is 90 °. In other words, the channel cross section at the upstream end of the third enlarged portion 234 is larger than the third jet outlet 237 of the third throat 233, and the outer peripheral edge of the channel cross section is from the edge of the third jet outlet 237. It is spaced from the outside in the radial direction and is located around the third ejection port 237.

  In the present embodiment, the first tapered portion 212, the second tapered portion 222, and the third tapered portion 232 have the same shape. Moreover, the 1st expansion part 221 and the 2nd expansion part 231 are the same shapes. The diameters of the first enlargement part 221, the second enlargement part 231 and the third enlargement part 234 are about 4 times the diameter of the first throat part 213, the diameter of the second throat part 223 and the diameter of the third throat part 233, respectively. About 5 times. The diameters of the first throat portion 213, the second throat portion 223, and the third throat portion 233 are desirably increased from upstream to downstream, and more desirably increased at a rate of 7% or less. Here, the increase rate is (the diameter of the downstream throat−the diameter of the upstream throat) ÷ the diameter of the downstream throat × 100 (%). For example, if the upstream throat is the first throat 213, the downstream throat is the second throat 223, and the upstream throat is the second throat 223, the downstream throat is the third throat. 233.

  In the fine bubble generating nozzle 2, the pressurized liquid 71 that has flowed into the nozzle flow path 20 from the nozzle inlet 201 flows into the first throat 213 while being gradually accelerated in the first taper portion 212. The flow rate of the pressurized liquid 71 in the first throat 213 is preferably 7 m to 30 m per second. In the first throat 213, the static pressure of the pressurized liquid 71 decreases, so that the gas dissolved in the pressurized liquid 71 becomes supersaturated and precipitates in the liquid as fine bubbles. The liquid containing fine bubbles, that is, the fine bubble-containing liquid 73 is ejected as a jet from the first ejection port 217 toward the first enlarged portion 221. Precipitation of fine bubbles is continued in the fine bubble-containing liquid 73 ejected to the first enlarged portion 221. The fine bubbles are further refined by a shearing force or the like generated in the first enlarged portion 221 by the jet flow from the first jet outlet 217.

  The fine bubble-containing liquid 73 flowing through the first enlarged portion 221 flows into the second throat portion 223 while being gradually accelerated in the second tapered portion 222, and jets from the second jet port 227 toward the second enlarged portion 231. Erupted as. The fine bubbles in the fine bubble-containing liquid 73 are further refined by a shearing force or the like generated in the second enlarged portion 231 by the jet flow.

  The fine bubble-containing liquid 73 flowing through the second enlarged portion 231 flows into the third throat portion 233 while being gradually accelerated at the third tapered portion 232, and jets from the third outlet 237 toward the third enlarged portion 234. Erupted as. The fine bubbles in the fine bubble-containing liquid 73 are further refined by a shearing force or the like generated in the third enlarged portion 234 by the jet flow. The fine bubble-containing liquid 73 passes through the third expansion part 234 and diffuses into the target liquid 91 in the storage part 5. The fine bubbles generated by the fine bubble generating nozzle 2 contain many so-called nanobubbles having a diameter of less than 1 μm.

  The target liquid 91 containing fine bubbles is taken out of the reservoir 5 via a delivery pipe (not shown) and used for various purposes. The target liquid 91 is used for cleaning semiconductor devices, for example. In addition, the target liquid 91 taken out from the storage unit 5 is returned to the pump 33 of the pressurized liquid generating unit 3, and stored via the pressurized liquid generating unit 3, the pressurized liquid channel 4 and the fine bubble generating nozzle 2. You may circulate to the part 5. Thereby, the density of fine bubbles in the target liquid 91 in the reservoir 5 (that is, the number of fine bubbles present in the unit volume of the target liquid 91) can be increased.

  In the fine bubble generating device 1, the driving of the pump 33 is stopped in the pressurized liquid generating unit 3 when the generation of the fine bubbles is stopped. The exhaust valve 64 is opened until the liquid flow from the pump 33 to the mixing nozzle 31 stops. Thereby, the pressurized gas in the dissolution flow path portion 32 is released to the outside through the exhaust valve 64. As a result, it is possible to prevent the liquid from flowing back to the mixing nozzle 31 and the pump 33 due to the expansion of the gas in the dissolution channel portion 32.

  FIG. 4 is a diagram for explaining the pressure loss in each part of the fine bubble generating nozzle 2. As shown in FIG. 4, the pressure loss in the introduction part 211 and the first taper part 212 is ΔPa1, and the pressure loss in the first throat part 213 is ΔPb1. Further, the pressure loss at the first enlarged portion 221 and the second taper portion 222 is ΔPa2, and the pressure loss at the second throat portion 223 is ΔPb2. The pressure loss at the second enlarged portion 231 and the third tapered portion 232 is ΔPa3, and the pressure loss at the third throat portion 233 is ΔPb3. The 3rd expansion part 234 is a short channel open | released toward the target liquid 91 in the storage part 5 open | released by air | atmosphere. Therefore, since the pressure loss in the third enlarged portion 234 is small, it is ignored here. An inlet pressure P0, which is a pressure at the nozzle inlet 201 when the pressure at the nozzle outlet 202 is set as a reference (zero), is expressed as Equation 1. The inlet pressure P0 automatically becomes a predetermined pressure when the valve control unit 63 controls the regulating valve 61 based on the output from the pressure sensor 62 (see FIG. 1). In the present embodiment, the inlet pressure P0 is about 0.1 MPa to about 0.5 MPa.

  ΔPbi in Equation 1 is a pressure loss in each throat. Since each throat portion is short, the pressure loss ΔPbi in each throat portion can be regarded as only a loss due to dynamic pressure, ignoring a loss due to friction. Therefore, ΔPbi is proportional to the square of the flow velocity at each throat.

  As described above, in each enlarged portion, the fine bubbles are further refined by the shearing force generated by the jet flow ejected from the throat connected to the upstream end of each enlarged portion. The state of the jets ejected from each throat to the enlarged part is approximately similar, and the shear stress generated in each enlarged part is proportional to the flow velocity of the jet from the throat. Therefore, the shearing force that is considered to be caused by the shearing stress, that is, the force that further refines the fine bubbles is proportional to the flow velocity of the jet from the throat. In other words, the force that further refines the fine bubbles in the jet from each throat is proportional to the square root of the pressure loss ΔPbi in each throat. For this reason, the direction which provides a some throat part can utilize a pressure effectively as force which refines | miniaturizes a bubble compared with the case where the throat part is one. For example, if the pressure loss ΔPbi in one throat is 200, the force for refining bubbles in the throat is 14.4 (= square root of 200), but instead of the throat, two throats are used. Is provided, the force for refining the bubbles in the two throats is 20 (= square root of 100 + square root of 100), and the force for refining the bubbles increases.

  In the fine bubble generating nozzle 2, it is considered that the fine bubbles are further refined when a force greater than a predetermined shearing force acts on the fine bubbles. However, not all of the fine bubbles contained in the fine bubble-containing liquid 73 ejected from the throat are refined to a desired size by one ejection. In the fine bubble generating nozzle 2, since a plurality of throat portions are provided in the nozzle flow path 20, the pressure loss ΔPbi in each throat portion is smaller than when only one throat portion is provided. However, since the shear force acting on the fine bubbles in the jet from the throat is proportional to the square root of the pressure loss ΔPbi of each throat as described above, even if the pressure loss ΔPbi is reduced to some extent, the shear force is It is larger than the size sufficient for further miniaturizing the fine bubbles.

For this reason, in the fine bubble generating nozzle 2, a plurality of throat portions are arranged in series in the nozzle flow path 20, and the fine bubble-containing liquid 73 is ejected a plurality of times, thereby further updating the fine bubbles in the fine bubble-containing liquid 73. Refinement can be performed multiple times. As a result, a large amount of fine bubbles (nanobubbles) can be stably generated. In measurement by LM10 and LM20 of NanoSight Limited, nanobubbles distributed in a range of less than 1 μm with a diameter of about 100 nm as a center are about 400 million in the target liquid 91 of 1 cm ³ by the fine bubble generation nozzle 2. Are generated. The “diameter of the fine bubbles” refers to the diameter measured by the measuring device.

  In the fine bubble generating nozzle 2, the fluid pressure loss (= ΔPa 1 + ΔPb 1) from the nozzle inlet 201, which is the upstream end of the nozzle flow path 20, to the first jet port 217 of the first throat 213 is the pressurized liquid at the nozzle inlet 201. It is preferably 30% or more of the inlet pressure P0 which is a pressure of 71. Thereby, in the 1st throat part 213 and the 1st expansion part 221, a large amount of fine bubbles can be deposited from the pressurizing liquid 71. As a result, the fine bubble generating nozzle 2 can generate a large amount of fine bubbles more stably. Here, the first taper portion 212, the first throat portion 213, the first jet port 217, the first enlarged portion 221, the second taper portion 222, the second throat portion 223, and the second jet port 227 are respectively connected to the upstream taper portion. , Upstream throat, upstream jet, enlarged portion, downstream taper, downstream throat, and downstream jet, the upstream throat (first throat 213) is the most upstream throat of the nozzle channel 20. is there. Further, the pressure loss of the fluid from the nozzle inlet 201 to the upstream jet outlet (first jet outlet 217) is preferably 30% or more of the inlet pressure P0 as described above.

  On the other hand, the second taper portion 222, the second throat portion 223, the second jet port 227, the second enlarged portion 231, the third taper portion 232, the third throat portion 233, and the third jet port 237 are respectively connected to the upstream taper portion, If considered as the upstream throat, upstream jet, enlarged portion, downstream taper, downstream throat, and downstream jet, the downstream jet (third jet 237) is the most downstream jet in the nozzle channel 20. The third enlarged portion 234 is another enlarged portion that is connected to the downstream outlet and expands the flow path area. By providing the 3rd expansion part 234, it controls that the flow of the object liquid 91 in the storage part 5 influences with respect to the fine bubble containing liquid 73 immediately after being ejected from the 3rd jet nozzle 237. Can do. Thereby, also in the fine bubble-containing liquid 73 immediately after ejection from the third ejection port 237, further refinement of the fine bubbles is stably performed, so that a large amount of fine bubbles can be generated more stably. .

  As described above, in the fine bubble generating nozzle 2, the inner surface of the first taper portion 212 is a part of a conical surface centered on the central axis J2 of the nozzle flow path 20, and as shown in FIG. In the cross section including J2, the angle α1 formed by the inner surface of the first tapered portion 212 is 90 ° or less. Thereby, the pressurizing liquid 71 can be rapidly accelerated while suppressing the pressure loss of the pressurizing liquid 71 in the first tapered portion 212. Further, from the viewpoint of shortening the length of the fine bubble generating nozzle 2 while maintaining the diameters of the introduction part 211 and the first throat part 213, the angle α1 formed by the inner surface of the first taper part 212 is 10 ° or more. It is preferable.

  Similarly, in the second taper portion 222, the inner surface of the second taper portion 222 is a part of a conical surface with the central axis J2 as the center, and the angle α2 formed by the inner surface of the second taper portion 222 is 10 ° or more and 90 °. When the angle is less than or equal to °, the length of the second tapered portion 222 can be shortened, and the fine bubble-containing liquid 73 can be accelerated quickly while suppressing the pressure loss of the fine bubble-containing liquid 73 in the second tapered portion 222. can do. Similarly, in the third taper portion 232, the inner surface of the third taper portion 232 is a part of a conical surface centered on the central axis J2, and the angle α3 formed by the inner surface of the third taper portion 232 is 10 ° or more 90 °. When the angle is less than or equal to °, the length of the third tapered portion 232 can be shortened, and the fine bubble-containing liquid 73 can be accelerated quickly while suppressing the pressure loss of the fine bubble-containing liquid 73 in the third tapered portion 232. can do.

  In the fine bubble generating nozzle 2, as described above, the diameter of the plurality of throats gradually increases from the upstream side of the nozzle flow path 20 to the downstream side, so that a large amount of fine bubbles can be generated more stably. it can. Further, even when the diameters of the first throat 213, the second throat 223, and the third throat 233 are all about 2.60 mm, a large amount of fine bubbles can be stably generated. From the above, in order to more stably generate a large amount of fine bubbles, the diameter of the third throat 233 is preferably equal to or larger than the diameter of the second throat 223, and the diameter of the second throat 223 is The diameter of the first throat 213 is preferable. In the fine bubble generating nozzle 2, the diameter of the first throat 213 is slightly larger than the diameter of the second throat 223, and the diameter of the second throat 223 is larger than the diameter of the third throat 233. Even if it is slightly larger, fine bubbles can be stably produced in large quantities.

  As described above, the length of the first throat 213 is 1.1 times or more the diameter of the first throat 213. Thereby, the flow in the 1st throat part 213 is stabilized, and in the jet flow ejected from the 1st throat part 213 and the 1st jet nozzle 217, a fine bubble is stably produced | generated in large quantities. Furthermore, further miniaturization of the fine bubbles is stably performed by a shearing force or the like generated by the jet flow from the first jet outlet 217. The lengths of the second throat 223 and the third throat 233 are 1.1 times or more the diameters of the second throat 223 and the third throat 233, respectively. Thereby, the flow in the 2nd throat part 223 and the 3rd throat part 233 is stabilized, and further refinement | miniaturization of a fine bubble is stably by the jet flow ejected from the 2nd jet nozzle 227 and the 3rd jet nozzle 237, respectively. Done. As a result, a large amount of fine bubbles can be generated more stably.

  The lengths of the first throat portion 213, the second throat portion 223, and the third throat portion 233 are not more than 10 times the diameters of the first throat portion 213, the second throat portion 223, and the third throat portion 233, respectively. Thereby, in each of the 1st throat part 213, the 2nd throat part 223, and the 3rd throat part 233, it can prevent that resistance which arises in fluid becomes large too much, and the 1st throat part 213, 2nd Highly accurate formation of the throat 223 and the third throat 233 can also be facilitated. From the viewpoint of more stably generating a large amount of fine bubbles, the lengths of the first throat 213, the second throat 223, and the third throat 233 are the first throat 213 and the second throat, respectively. It is more preferable that the diameter is 1.5 to 2 times the diameter of 223 and the third throat 233.

  In the fine bubble generating nozzle 2, in the cross section including the central axis J2, the angle β1 between the first surface 221a of the first enlarged portion 221 and the central axis J2, the first surface 231a of the second enlarged portion 231 and the central axis J2 And the angle β3 formed between the first surface 234a of the third enlarged portion 234 and the central axis J2 are each 90 °. Thereby, the influence which the inner surface of an expansion part has with respect to the jet flow spouted from the spout of a throat toward each expansion part can be reduced. As a result, a large amount of fine bubbles can be generated more stably.

  FIG. 5 is a cross-sectional view showing another preferred fine bubble generating nozzle. In the fine bubble generating nozzle 2a shown in FIG. 5, in the first enlargement unit 221, the second enlargement unit 231, and the third enlargement unit 234, the above-mentioned angles β1, β2, and β3 are 45 °, respectively. The first surface 221a of the first enlarged portion 221, the first surface 231a of the second enlarged portion 231, and the first surface 234a of the third enlarged portion 234 are each part of a substantially conical surface centered on the central axis J2. It is. The flow passage area of the first enlarged portion 221 gradually increases from the first jet port 217 to the boundary between the first surface 221a and the second surface 221b, and is constant from the boundary to the downstream end of the second surface 221b. The same applies to the flow passage areas of the second enlarged portion 231 and the third enlarged portion 234. Also in the fine bubble generating nozzle 2a, it is possible to reduce the influence of the inner surface of the enlarged portion on the jet flow ejected from the throat outlet toward each enlarged portion. As a result, a large amount of fine bubbles can be generated more stably. For these reasons, by setting the above-mentioned angles β1, β2, and β3 to 45 ° or more and 90 ° or less, a large amount of fine bubbles can be generated more stably.

  In the fine bubble generating nozzle 2 shown in FIG. 4, the total length of the first enlarged portion 221 and the second tapered portion 222, that is, the first jet port 217 and the second throat portion which are the downstream ends of the first throat portion 213. A distance between the upstream end of 223 (hereinafter referred to as “distance between throats”) L1 is about 4.6 times the diameter of the first enlarged portion 221. Further, the inter-throat distance L2 between the second jet port 227 of the second throat 223 and the upstream end of the third throat 233 is about 4.6 times the diameter of the second enlarged portion 231.

  FIG. 6 is generated when the lengths of the first enlarged portion 221 and the second enlarged portion 231 are changed and the throat distances L1 and L2 are changed in the fine bubble generating nozzle 2 shown in FIG. 3 and FIG. It is a figure which shows the density of the fine bubble formed. As shown in FIG. 6, in the fine bubble generating nozzle 2 in which the throat distances L1 and L2 are about 4.6 times the diameter of the enlarged portion, the throat distances L1 and L2 are about the diameter of the enlarged portion, respectively. Compared with the case of 3.2 times and the case of about 6 times, fine bubbles can be generated more stably and in large quantities. From the viewpoint of more stably generating a large amount of fine bubbles, the throat distance L1 is preferably not less than 3.5 times and not more than 5.5 times the diameter of the first enlarged portion 221. L2 is preferably not less than 3.5 times and not more than 5.5 times the diameter of the second enlarged portion 231.

  As described above, the fine bubble generating nozzle 2 is formed by connecting the first nozzle portion 21, the second nozzle portion 22, and the third nozzle portion 23. By manufacturing the 1st nozzle part 21, the 2nd nozzle part 22, and the 3rd nozzle part 23 separately, the fine bubble production | generation nozzle 2 can be manufactured easily and with high precision. Further, by disassembling the fine bubble generating nozzle 2 into the first nozzle portion 21, the second nozzle portion 22, and the third nozzle portion 23, the maintenance of the fine bubble generating nozzle 2 can be easily performed.

  FIG. 7 is an enlarged cross-sectional view of the fine bubble generating nozzle 2b of the fine bubble generating apparatus according to the second embodiment of the present invention. The fine bubble generating apparatus according to the second embodiment includes a fine bubble generating nozzle 2b having a tip part structure different from that of the fine bubble generating nozzle 2 instead of the fine bubble generating nozzle 2 shown in FIG. Moreover, the shape of the site | part to which the fine bubble production | generation nozzle 2b of the storage part 5 is attached differs from what is shown in FIG. Other configurations are the same as those of the fine bubble generating device 1 shown in FIG. 1, and the same reference numerals are given to the corresponding configurations in the following description.

  In the fine bubble generating nozzle 2b shown in FIG. 7, the third enlarged portion 234 is omitted from the fine bubble generating nozzle 2 shown in FIG. Therefore, the third outlet 237 of the fine bubble generating nozzle 2 b is the nozzle outlet 202 that is the most downstream outlet of the nozzle channel 20 and the downstream end of the nozzle channel 20.

  As shown in FIG. 7, a through hole 530 is provided in the side wall 51 of the reservoir 5. The tip of the fine bubble generating nozzle 2 b is inserted into the through hole 530 from the outside of the reservoir 5, and the fine bubble generating nozzle 2 b is attached to the side wall portion 51. As a result, a hole 53 that is recessed outward is provided on the inner surface 52 of the side wall 51 of the reservoir 5. The bottom surface 53a of the hole 53 is the tip surface of the fine bubble generating nozzle 2b. The third outlet 237 of the fine bubble generating nozzle 2 b is located at the center of the bottom surface 53 a of the hole 53 and is connected to the hole 53. The bottom surface 53a of the hole 53 is a substantially annular surface centering on the central axis J2 of the fine bubble generating nozzle 2b, and spreads radially outward from the edge of the third ejection port 237. The inner surface 53b of the hole 53 is a substantially cylindrical surface centered on the central axis J2 of the fine bubble generating nozzle 2b, and the cross section of the hole 53 perpendicular to the central axis J2 is substantially circular.

  The hole 53 enlarges the flow path area from the third ejection port 237 to the inner surface 52 of the side wall 51 of the reservoir 5 as compared with the third throat 233. That is, the hole 53 plays the same role as the third enlarged portion 234 of the fine bubble generating nozzle 2 shown in FIG. By providing the hole 53 in the reservoir 5, the flow of the target liquid 91 (see FIG. 1) in the reservoir 5 can flow without the third enlarged portion 234 in the fine bubble generating nozzle 2 b. It is possible to inhibit the fine bubble-containing liquid 73 immediately after being ejected from 237 from being affected. Thereby, also in the fine bubble-containing liquid 73 immediately after ejection from the third ejection port 237, further refinement of the fine bubbles is stably performed, so that a large amount of fine bubbles can be generated more stably. .

  FIG. 8 is a cross-sectional view showing a fine bubble generating device 1a according to the third embodiment. In the fine bubble generating device 1a, the pressurized liquid generating unit 3 includes a dissolution channel unit 32a having a structure different from that of the dissolution channel unit 32 shown in FIG. Other configurations are the same as those of the fine bubble generating device 1 shown in FIG. 1, and the same reference numerals are given to the corresponding configurations in the following description.

  As shown in FIG. 8, the dissolution channel portion 32a includes a first horizontal channel 321, a second horizontal channel 322, a third horizontal channel 323, and a first horizontal channel arranged in order from the upper side to the lower side. A four horizontal flow path 324 and a fifth horizontal flow path 325 are provided. The horizontal flow paths 321 to 325 are connected in series by a connection flow path 320 curved in an angle shape. The inner surfaces of the horizontal flow path and the connection flow path 320 are mirror-finished, for example. FIG. 9 is a view showing a longitudinal section of the horizontal flow paths 321 to 325 at the position of the arrow AA in FIG. The cross section perpendicular to the longitudinal direction of the horizontal flow paths 321 to 325 is substantially circular.

  As shown in FIG. 8, the mixing nozzle 31 that ejects the mixed fluid 72 is ejected at the upstream end of the first horizontal flow path 321 (that is, the left end in FIG. 8), as in FIG. It is attached. The mixed fluid 72 is ejected from the mixing nozzle 31 above the liquid level of the mixed fluid 72 in the first horizontal flow path 321 and directly collides with the liquid level. A part or the whole of the mixed fluid ejection port 312 (see FIG. 2) of the mixing nozzle 31 may be positioned below the liquid level of the mixed fluid 72 in the first horizontal flow path 321. Thereby, the mixed fluid 72 immediately after being ejected from the mixing nozzle 31 directly collides with the mixed fluid 72 flowing in the first horizontal flow path 321.

  As shown in FIGS. 8 and 9, a damming portion 34 is provided at the lower part of the downstream end of the first horizontal flow path 321. The blocking portion 34 prevents the flow of the mixed fluid 72 in the first horizontal flow path 321, whereby the mixed fluid 72 is stored so as to stay in the first horizontal flow path 321. The mixed fluid 72 overflows beyond the blocking portion 34, falls in the connection channel 320, and flows into the upstream end of the second horizontal channel 322.

  In the second horizontal flow path 322, the mixed fluid 72 flows from the right side to the left side in FIG. Also in the second horizontal flow path 322, a damming portion 34 is provided below the downstream end. In the second horizontal flow path 321, the blocking portion 34 prevents the flow of the mixed fluid 72, whereby the mixed fluid 72 is stored so as to stay in the second horizontal flow path 321. The mixed fluid 72 overflows beyond the blocking portion 34, falls in the connection channel 320, and flows into the upstream end of the third horizontal channel 322.

  Similarly, the third horizontal flow path 323 and the fourth horizontal flow path 324 are also provided with a damming portion 34 to store the mixed fluid 72. As described above, the blocking portion 34 is a portion that is fixed to the lower portion of the horizontal flow path and blocks the lower portion. At the ends of the third and fourth horizontal flow paths 323 and 324, the mixed fluid 72 falls toward the next horizontal flow path. In the third horizontal channel 323, the mixed fluid 72 flows from the left side to the right side in FIG. 1 under a pressurized environment, and in the fourth horizontal channel 324, the mixed fluid 72 flows from the right side to the left side in the pressurized environment. It flows to. In the first horizontal channel 321 to the fourth horizontal channel 324, the mixed fluid 72 flows below the gas while in contact with the gas.

  Unlike the first to fourth horizontal flow paths 321-324, the fifth horizontal flow path 325 is not provided with the damming portion 34. There is no gas layer in the fifth horizontal flow path 325, and in the liquid that fills the fifth horizontal flow path 325, there are slight bubbles near the upper surface of the fifth horizontal flow path 325. It has become. In the fifth horizontal flow path 325, the mixed fluid 72 flowing in from the fourth horizontal flow path 324 flows from the left side to the right side in FIG. The fifth horizontal channel 325 is longer than the other horizontal channels 321 to 324.

  In the pressurizing liquid generating unit 3, the horizontal flow paths 321 to 325 and the connection flow path 320 flow down from top to bottom while repeating slowing up and down in steps (that is, alternating the horizontal flow and the downward flow). In the mixed fluid 72 (flowing repeatedly), the gas is gradually dissolved in the liquid under pressure. In the fifth horizontal flow path 325, the concentration of the gas dissolved in the liquid is substantially equal to 60% to 90% of the (saturated) solubility of the gas under a pressurized environment. And the excess gas which did not melt | dissolve in the liquid exists in the 5th horizontal flow path 325 as a bubble of the magnitude | size which can be visually recognized. Since the direction of the flow of the mixed fluid 72 in the horizontal flow paths adjacent to each other in the upper and lower directions is reversed, the pressurized liquid generating unit 3 can be reduced in size.

  FIG. 10 is an enlarged view showing the damming portion 34 together with the cross section of the horizontal flow path. The dam member 34 has a linear shape in which the upper end 341 is horizontal and perpendicular to the direction in which the channel extends, and has a minute through-hole 342 that penetrates the dam member 34 along the horizontal channel at the lowermost part. The upper side of the upper end 341 is an opening 35 through which the mixed fluid 72 overflowing from the blocking portion 34 flows. When manufacturing the dissolution channel portion 32a, first, a plate member is prepared in which a minute through hole 342 and a semicircular opening 35 are formed on a disc having the same size as the cross section of the horizontal channel. Then, welding is performed such that the plate member is sandwiched between the horizontal flow paths 321 to 324 and the connection flow path 320.

  By providing the blocking portion 34, the height of the liquid level, that is, the water level is maintained substantially constant in the first to fourth horizontal flow paths 321 to 324 even if the temperature or viscosity of the mixed fluid 72 changes. Is done. As a result, the contact area between the gas and the mixed fluid 72 is maintained approximately constant in the first to fourth horizontal flow paths 321 to 324. As a result, the production capacity of the pressurized liquid 71 can be easily predicted by calculation at the time of design. Moreover, even if the production amount of the pressurizing liquid 71 is changed, the pressurizing liquid 71 in which a desired amount of gas is dissolved per unit volume can be easily obtained.

  In particular, when the pressurization liquid generating unit 3 is required to have sanitary cleanliness (so-called sanitary characteristics) such as food and medicine, or the high degree of cleanliness such as ultrapure water used for semiconductor processing or the like. When required, the cross section of the tube forming the flow path is preferably a circular shape that can be easily mirror-finished, and a sanitary circular tube can be easily obtained.

  When the flow path cross section is circular, as shown in FIG. 11, the gas-liquid contact area greatly varies due to slight vertical movement of the liquid level as the liquid level moves up and down from the center of the flow path. In FIG. 11, the radius of the horizontal channel is expressed as “1”, and the larger the absolute value of the increase rate of the gas-liquid contact area, the greater the change in the gas-liquid contact area with respect to the liquid level fluctuation. ing. When the blocking part 34 is not provided, the liquid level greatly varies depending on the production amount of the pressurized liquid 71. Therefore, it is particularly preferable that the damming portion 34 is provided when the cross section of the horizontal flow path is circular. The liquid level is preferably maintained at 0.8 to 1.2 in FIG. Moreover, since the gas-liquid contact area can be maintained wide by the damming portion 34, the pressurized liquid generating portion 3 can be downsized.

  Furthermore, since the cross section of the flow path is circular, the pressure resistance performance of the flow path can be improved. Thereby, a pipe wall can be made thin. In addition, as long as the cross section of the inner surface of a flow path is circular, the external shape of a flow path may be other shapes, such as a rectangle.

  The dam member 34 is provided in the first to fourth horizontal flow paths 321 to 324 between the downstream connection flow path 320, that is, at a position immediately before the mixed fluid 72 is directed to the next horizontal flow path. Therefore, the contact area between the gas and the liquid can be increased in each horizontal flow path. As a result, the production capacity of the pressurized liquid 71 can be improved.

  Since the minute piercing hole 342 is provided in the damming part 34, a part of the mixed fluid 72 dammed by the damming part 34 is next to the minute through hole 342 while the pressurized liquid 71 is produced. To the horizontal channel. The amount of the mixed fluid 72 flowing out from the minute through-hole 342 is small, and the state where the mixed fluid 72 overflows from the damming portion 34 is maintained. For example, the amount of the mixed fluid 72 flowing down from the minute through hole 342 is 1/5 or less, more preferably 1/10 or less, of the mixed fluid 72 exceeding the dam portion 34. On the other hand, by providing the minute through hole 342, after the production of the pressurizing liquid 71 is stopped, the liquid remaining in the dissolving channel part 32a is naturally allowed to flow into the pressurized liquid channel 4 side, that is, the dissolving channel part. 32a can be discharged to the outside. Therefore, when the sanitary characteristic is required for the dissolution channel portion 32a, it is particularly preferable that the minute passage hole 342 is provided in the dissolution channel portion 32a.

  As shown in FIG. 8, the dissolution flow path portion 32 a further includes a surplus gas separation section 326 extending upward from the upper surface on the downstream side of the fifth horizontal flow path 325, and the surplus gas separation section 326 contains the mixed fluid 72. It is full. The surplus gas separation part 326 is divided into two parts at the lower part and connected to the fifth horizontal flow path 325, respectively, and connected to one at the upper part. Each pipe line of the surplus gas separation unit 326 is also circular in cross section. The upper end portion of the surplus gas separation unit 326 is opened to the atmosphere via the throttle unit 327. The bubbles of the mixed fluid 72 flowing through the fifth horizontal flow path 325 rise in the surplus gas separation unit 326 and are discharged together with the surplus mixed fluid 72. By separating the lower part of the surplus gas separation part 326 into two parts, the surplus gas is more reliably separated. In addition, the lower part of the excess gas separation part 326 may be divided into three or more, and may be only one.

  In this manner, the excess gas is separated from the mixed fluid 72, whereby the pressurized liquid 71 that does not substantially include bubbles of a size that can be easily visually recognized is generated, and is downstream of the fifth horizontal channel 325. Is sent to the pressurized liquid flow path 4 connected to the end of this (that is, the right end in FIG. 1). In the present embodiment, the pressurized liquid 71 dissolves a gas that is about twice or more the gas (saturated) solubility under atmospheric pressure. The mixed fluid 72 that flows through the horizontal flow paths 321 to 325 and the connection flow path 320 in the dissolution flow path section 32a can also be regarded as the pressurized liquid 71 that is being generated.

  The fine bubble generating device 1a further includes a regulating valve 61, a pressure sensor 62, and a valve control unit 63, similarly to the fine bubble generating device 1 shown in FIG. In the present embodiment, a proportional control valve is used as the regulating valve 61, but the regulating valve 61 may be another type of valve such as a relief valve, a normal valve, or a fixed throttle. An exhaust valve 64 is also provided above the first horizontal flow path 321. In the fine bubble generating device 1a, the measurement value of the pressure in the dissolution channel 32a output from the pressure sensor 62 is set to a predetermined pressure (preferably 0.1 MPa to 0.45 MPa). The regulating valve 61 is controlled by the valve control unit 63. The pressurizing liquid 71 guided from the dissolution channel portion 32 a to the pressurizing liquid channel 4 flows into the fine bubble generating nozzle 2.

  FIG. 12 is a diagram illustrating another example of the blocking portion. The dam member 34a shown in FIG. 12 is a beam-like member provided in a horizontal channel and in a direction that is horizontal and perpendicular to the direction in which the channel extends. The mixed fluid 72 flows down to the next horizontal flow path beyond the upper end 341 of the blocking portion 34. In addition, a gap between the lower end of the damming portion 34 and the lower portion of the horizontal flow path functions as a minute through hole 342. The action and effect of the blocking portion 34a in FIG. 12 are the same as those shown in FIG.

  FIG. 13 is a diagram illustrating another example of a portion other than the surplus gas separation unit 326 of the dissolution flow path unit 32a. In the dissolution flow path part 32a of FIG. 13, the weir part 34 is provided with the minute through hole 342 omitted from that shown in FIG. Further, in the dissolution flow path portion 32a, a bypass flow path 36 that connects the horizontal flow paths arranged in the vertical direction is provided on the upstream side of the damming portion 34 instead of the minute through hole 342. That is, a bypass channel 36 that connects the first horizontal channel 321 and the second horizontal channel 322 up and down is provided on the upstream side of the blocking portion 34 of the first horizontal channel 321, and the second horizontal channel 322. A bypass channel 36 that connects the second horizontal channel 322 and the third horizontal channel 323 up and down is provided on the upstream side of the blocking portion 34, and the third horizontal channel 323, the fourth horizontal channel 324, In the same manner, a bypass channel 36 is also provided between the fourth horizontal channel 324 and the fifth horizontal channel 325. The horizontal channels lined up and down communicate with each other through the connection channel 320, while the bypass channel 36 is a minute channel that separately communicates these horizontal channels. Other structures of the fine bubble generating device 1a and the dissolution flow path portion 32a are the same as those shown in FIG.

  Also in the dissolution channel part 32a shown in FIG. 13, the height of the liquid surface of the mixed fluid 72 is provided in the first to fourth horizontal channels 321 to 324 by providing the blocking part 34 as in FIG. Is maintained approximately constant. Thereby, the contact area of gas and liquid is maintained substantially constant. As a result, the pressurized liquid 71 in which a desired amount of gas is dissolved per unit volume can be easily obtained. Moreover, since the dam member 34 is provided at a position immediately before the mixed fluid 72 heads to the next horizontal flow path, the contact area between the gas and the liquid can be increased in each horizontal flow path.

  Since the bypass flow path 36 is provided on the upstream side of the damming portion 34, a part of the mixed fluid 72 blocked by the damming portion 34 while the pressurized liquid 71 is produced is It flows down from 36 to the next horizontal flow path. The amount of the mixed fluid 72 flowing down from the bypass channel 36 is small, and the state where the mixed fluid 72 overflows from the damming portion 34 is maintained. The amount of the mixed fluid 72 flowing down the bypass flow path 36 is 1/5 or less, more preferably 1/10 or less, of the mixed fluid 72 exceeding the blocking portion 34. On the other hand, by providing the bypass flow path 36, as in the case of FIG. 8, after the production of the pressurizing liquid 71 is stopped, the liquid remaining in the dissolution flow path section 32a is naturally allowed to flow into the pressurizing liquid flow path 4. Can be drained to the side.

  The micro through-hole 342 in FIG. 10, the micro through-hole 342 in FIG. 12, and the bypass flow path 36 in FIG. 13 included in the damming portion 34 in FIG. 8 are all upstream of the damming portions 34 and 34 a. The space in the horizontal flow path (that is, the lower portion of the space where the mixed fluid 72 is stored by the damming portions 34 and 34a) and the space downstream of the damming portions 34 and 34a are connected to each other, and the horizontal on the upstream side A part of the mixed fluid 72 stored in the flow path functions as a communication flow path that leads to a space downstream of the blocking portions 34 and 34a. The communication channel having such a function can be easily realized by the structures shown in FIGS. 10, 12, and 13, but the communication channel is not limited to these structures. For example, a communication flow path that guides the mixed fluid 72 stored by the damming portion 34 to the connection flow path 320 may be provided. Further, the bypass flow path 36 may be provided away from the damming portion 34 on the upstream side.

  FIG. 14 is a cross-sectional view showing a fine bubble generating device 1b according to the fourth embodiment. In the fine bubble generating device 1b, a filter 8 is disposed between the pressurized liquid generating unit 3 and the fine bubble generating nozzle 2. Other configurations are the same as those of the fine bubble generating device 1 shown in FIG. 1, and the same reference numerals are given to the corresponding configurations in the following description.

  In the fine bubble generating device 1b shown in FIG. 14, when the pressurized liquid 71 passes through the filter 8, particles in the pressurized liquid 71 are removed. Particles are generated from raw water, a pump 33, a mixing nozzle 31, a flow path, and the like. The minimum particle diameter that can be removed by the filter 8 (the minimum diameter when the particle is regarded as a sphere) is the mode value of the diameter of the fine bubbles generated when the pressurized liquid 71 passes through the fine bubble generation nozzle 2. That is, it is smaller than the diameter of the bubble with the largest number. Specifically, the average width of the through holes of the filter 8 is smaller than the mode value of the diameter of the fine bubbles. In other words, the size of the particles that can be removed by the filter 8 is smaller than the most frequent size of the fine bubbles. However, when the minimum diameter (size) of the particles that can be removed by the filter 8 is provided by the manufacturer of the filter 8, the value may be regarded as the minimum diameter.

  In the fine bubble generating device 1 b, when passing through the filter 8, there are no fine bubbles in the pressurized liquid 71, or most of the existing bubbles are not captured by the filter 8. Therefore, particles in the pressurizing liquid 71 are removed by the filter 8, but gas dissolved in the pressurizing liquid 71 passes through the filter 8. Then, when the pressurized liquid 71 passes through the fine bubble generating nozzle 2, a large amount of fine bubbles are generated from the pressurized liquid 71.

  If a liquid containing fine bubbles is generated and then a filter is used to remove particles from the liquid, the fine bubbles in the liquid are trapped by the filter and large bubbles are generated in the filter. There is a possibility that a phenomenon such as a decrease in the number of particles or a decrease in the processing flow rate of the filter may occur. In the fine bubble generating device 1b, the pressurized liquid 71 passes through the filter 8 on the upstream side of the fine bubble generating nozzle 2, thereby generating a liquid containing fine bubbles and from which particles are removed. Is done.

  In the fine bubble generating device 1 b, an auxiliary filter having an average through hole width larger than that of the filter 8 may be provided on the pressurized liquid channel 4 between the dissolution channel unit 32 and the filter 8. Since the minimum diameter of particles that can be removed by the auxiliary filter is larger than the minimum diameter of particles that can be removed by the filter 8, large particles in the pressurized liquid 71 are removed by the auxiliary filter, and the filter 8 is sufficiently small. Particles are removed. As a result, the life of the filter 8 can be extended. Since the fine filter 8 is expensive, the running cost of the filter 8 can be reduced by providing the auxiliary filter as described above.

  For example, the auxiliary filter removes particles having a minimum diameter of 1000 nm or more, and the filter 8 removes particles having a minimum diameter of 100 nm or more. In some cases, the filter 8 removes particles having a minimum diameter of 30 nm or 15 nm. In the manufacturing process of a semiconductor device, when the fine bubble generating device 1b shown in FIG. 14 is used for cleaning liquid generation of a wafer cleaning device, if the minimum line width of the semiconductor circuit is 19 nm, for example, the mode of the diameter of the nanobubbles Is about 100 nm, and the minimum diameter of particles removed by the filter 8 is about 15 nm.

  FIG. 15 is an enlarged cross-sectional view of the fine bubble generating nozzle 2c of the fine bubble generating apparatus according to the fifth embodiment of the present invention. FIG. 16 is a view of the fine bubble generating nozzle 2c as viewed from the front end side (downstream end side). The fine bubble generating apparatus according to the fifth embodiment includes a fine bubble generating nozzle 2c having a structure different from that of the fine bubble generating nozzle 2 instead of the fine bubble generating nozzle 2 shown in FIG. Other configurations are the same as those of the fine bubble generating device 1 shown in FIG. 1, and the same reference numerals are given to the corresponding configurations in the following description.

  As shown in FIGS. 15 and 16, the fine bubble generating nozzle 2c has a substantially cylindrical shape centered on the central axis J3. The fine bubble generating nozzle 2 c includes two nozzle channels 20, a first branch part 251, a second branch part 252, a third branch part 253, and a lead-out part 26. The two nozzle channels 20 have the same structure, and are arranged in parallel to the central axis J3 as shown in FIG. Each nozzle flow path 20 is similar to the nozzle flow path 20 of the fine bubble generating nozzle 2 shown in FIG. 3, the introduction part 211, the first taper part 212, the first throat part 213, which are continuous in order from the upstream side, The first enlarged portion 221, the second tapered portion 222, the second throat portion 223, the second enlarged portion 231, the third tapered portion 232, the third throat portion 233, and the third enlarged portion 234 are provided. . The introduction part 211 is shared by the two nozzle channels 20. The shape of each tapered portion, each throat portion, and each enlarged portion is substantially the same as that of the nozzle channel 20 shown in FIG.

  Two first taper portions 212 are connected to the downstream end of the introduction portion 211. Between the two 1st taper parts 212, the 1st branch part 251 located on the central axis J3 is arrange | positioned. In the present embodiment, the outer surface of the first branch portion 251 is the inner surface of the two first tapered portions 212. The pressurizing liquid 71 (see FIG. 1) guided from the pressurizing liquid channel 4 to the introducing portion 211 is branched into two first tapered portions 212 by the first branching portion 251. In other words, the first branching unit 251 branches the pressurized liquid 71 into the two nozzle channels 20.

  The pressurized liquid 71 branched to each first tapered portion 212 is ejected from the first ejection port 217 of the first throat portion 213 to the first enlarged portion 221. As described above, in the first throat portion 213 and the first enlarged portion 221, the gas dissolved in the pressurized liquid 71 is precipitated as fine bubbles, and the fine bubbles are further refined by a shearing force or the like generated by the jet flow. Is done. The two first enlarged portions 221 merge at the downstream portion, and the fine bubble-containing liquid 73 (see FIG. 1) flowing through each first enlarged portion 221 joins before flowing into the second tapered portion 222. .

  Between the two 2nd taper parts 222, the 2nd branch part 252 located on the central axis J3 is arrange | positioned. The fine bubble-containing liquid 73 is branched into two second tapered portions 222 by the second branch portion 252. The fine bubble-containing liquid 73 branched to each second tapered portion 222 is ejected from the second ejection port 227 of the second throat 223 to the second enlarged portion 231. Thereby, the fine bubbles in the fine bubble-containing liquid 73 are further refined. The two second enlarged portions 231 merge at the downstream portion in the same manner as the first enlarged portion 221, and the fine bubble-containing liquid 73 flowing through each second enlarged portion 231 is before flowing into the third tapered portion 232. To join.

  Between the two third taper portions 232, a third branch portion 253 located on the central axis J3 is disposed. The fine bubble-containing liquid 73 is branched into two third tapered portions 232 by the third branch portion 253. The fine bubble-containing liquid 73 branched to each third tapered portion 232 is ejected from the third ejection port 237 of the third throat 233 to the third enlarged portion 234. Thereby, the fine bubbles in the fine bubble-containing liquid 73 are further refined. The downstream ends of the two third enlarged portions 234 are connected to the derivation unit 26, and the fine bubble-containing liquid 73 ejected from each third ejection port 237 to the third enlarged portion 234 passes through the derivation unit 26. And supplied into the target liquid 91 (see FIG. 1) in the reservoir 5.

  In the fine bubble generating nozzle 2c, by providing a plurality of nozzle channels 20 arranged in parallel, the diameters of the first jet port 217, the second jet port 227, and the third jet port 237 are not increased, or The supply amount of the fine bubble-containing liquid 73 to the target liquid 91 can be increased while suppressing the increase in diameter. Thereby, increase of the force added to the fine bubble production | generation nozzle 2c by ejection of the fine bubble containing liquid 73 can be suppressed. Moreover, the enlargement of the storage part 5 and the fine bubble production | generation apparatus can be suppressed. Thus, by using the fine bubble generating nozzle 2c, it is possible to easily cope with a change in the flow rate of the fine bubble-containing liquid 73, that is, a change in the supply amount of the fine bubbles.

  In the fine bubble generating nozzle 2 c, the gas is dissolved in the pressurized liquid 71 on the upstream side of the first branch portion 251, and is present uniformly in the pressurized liquid 71. Therefore, when the first branch portion 251 branches to the plurality of nozzle channels 20, the gas is prevented from being biased to any of the nozzle channels 20. As a result, the amount of fine bubbles ejected from the plurality of nozzle channels 20 can be made uniform. Moreover, since the downstream part of the some 1st expansion part 221 and the downstream part of the some 2nd expansion part 231 have joined, the quantity of the fine bubble ejected from the several nozzle flow path 20 is made further equal. can do.

  In the fine bubble generating device 1 shown in FIG. 1, the pressurized liquid flow path 4 is branched into two pipes, and the target liquid in the reservoir 5 is supplied from two fine bubble generating nozzles 2 provided at the ends of the two pipes. The fine bubble-containing liquid 73 may be supplied to 91. As described above, in the pressurizing liquid 71 in the pressurizing liquid channel 4, the gas is dissolved in the pressurizing liquid 71 and is present uniformly in the pressurizing liquid 71. Therefore, when the pressurized liquid channel 4 is branched into a plurality of pipes, the gas is prevented from being biased to any one of the pipes. As a result, the amount of fine bubbles ejected from the plurality of fine bubble generating nozzles 2 can be made uniform.

  FIG. 17 is an enlarged cross-sectional view of the fine bubble generating nozzle 2d of the fine bubble generating apparatus according to the sixth embodiment of the present invention. FIG. 18 is a view of the fine bubble generating nozzle 2d as viewed from the front end side (downstream end side). The fine bubble generating apparatus according to the sixth embodiment includes a fine bubble generating nozzle 2d having a structure different from that of the fine bubble generating nozzle 2 instead of the fine bubble generating nozzle 2 shown in FIG. Other configurations are the same as those of the fine bubble generating device 1 shown in FIG. 1, and the same reference numerals are given to the corresponding configurations in the following description.

  As shown in FIGS. 17 and 18, the fine bubble generating nozzle 2d has a substantially cylindrical shape centered on the central axis J3. The fine bubble generating nozzle 2 d includes seven nozzle channels 20, a first branch part 251, a second branch part 252, a third branch part 253, and a lead-out part 26. The seven nozzle channels 20 have the same structure as each other, and are arranged in parallel to the central axis J3. Specifically, one nozzle channel 20 is located on the central axis J3, and the other six nozzle channels 20 are arranged at equiangular intervals around the nozzle channel 20 on the central axis J3. .

  As shown in FIG. 17, each nozzle flow path 20 is similar to the nozzle flow path 20 of the fine bubble generating nozzle 2 shown in FIG. 3, an introduction portion 211 that is continuous in order from the upstream side, a first taper portion 212, The first throat 213, the first enlarged portion 221, the second tapered portion 222, the second throat portion 223, the second enlarged portion 231, the third tapered portion 232, the third throat portion 233, and the second 3 enlargement unit 234. The introduction part 211 is shared by the seven nozzle channels 20. The shape of each tapered portion, each throat portion, and each enlarged portion is substantially the same as that of the nozzle channel 20 shown in FIG.

  Seven first tapered portions 212 are connected to the downstream end of the introducing portion 211. A first branch portion 251 is disposed between the seven first taper portions 212. A second branch portion 252 is disposed between the seven second taper portions 222, and a third branch portion 253 is disposed between the seven third taper portions 232. The seven first enlarged portions 221 and the seven second enlarged portions 231 merge at their respective downstream portions. The downstream ends of the seven third enlarged portions 234 are connected to the derivation unit 26.

  In the fine bubble generating nozzle 2d, the pressurizing liquid 71 guided from the pressurizing liquid channel 4 to the introduction unit 211 is branched into the seven nozzle channels 20 by the first branching unit 251. In the nozzle flow path 20, the gas dissolved in the pressurized liquid 71 is precipitated as fine bubbles, and the fine bubbles are further refined. Then, the fine bubble-containing liquid 73 ejected from the third ejection port 237 of each nozzle channel 20 to the third enlarged portion 234 is supplied into the target liquid 91 in the reservoir 5 via the outlet 26. .

  In the fine bubble generating nozzle 2d, similarly to the fine bubble generating nozzle 2c shown in FIG. 15, by providing a plurality of nozzle channels 20 arranged in parallel, the first jet port 217, the second jet port 227, and the third nozzle channel 20 are provided. The supply amount of the fine bubble-containing liquid 73 to the target liquid 91 can be increased without increasing the diameter of the ejection port 237 or while suppressing the increase in the diameter. Thereby, increase of the force added to the fine bubble production | generation nozzle 2d by ejection of the fine bubble containing liquid 73 can be suppressed. Moreover, the enlargement of the storage part 5 and the fine bubble production | generation apparatus can be suppressed. Thus, by using the fine bubble generating nozzle 2d, it is possible to easily cope with a change in the flow rate of the fine bubble-containing liquid 73, that is, a change in the supply amount of the fine bubbles.

  In the fine bubble generating nozzle 2d, the gas is dissolved in the pressurizing liquid 71 on the upstream side of the first branching portion 251 and exists uniformly in the pressurizing liquid 71. Therefore, when the first branch portion 251 branches to the plurality of nozzle channels 20, the gas is prevented from being biased to any of the nozzle channels 20. As a result, the amount of fine bubbles ejected from the plurality of nozzle channels 20 can be made uniform. Moreover, since the downstream part of the some 1st expansion part 221 and the downstream part of the some 2nd expansion part 231 have joined, the quantity of the fine bubble ejected from the several nozzle flow path 20 is made further equal. can do.

  As mentioned above, although embodiment of this invention has been described, this invention is not limited to the said embodiment, A various change is possible.

  In the fine bubble generating nozzle described above, the inner surfaces of the first taper part 212, the second taper part 222, and the third taper part 232 do not necessarily have to be part of a substantially conical surface, for example, the inner side of the substantially conical surface. It may be a curved surface that bulges in a convex shape, or a curved surface that bulges in a concave shape outside the substantially conical surface. Further, even if the structure is different from the example shown in FIG. 7, the fine bubble-containing liquid 73 immediately after being ejected from the third ejection port 237 is not significantly affected by the flow of the target liquid 91 in the reservoir 5. If the fine bubble generating nozzle is arranged as described above, the third expansion unit 234 may be omitted from the fine bubble generating nozzle.

  In the fine bubble generating nozzle described above, the cross section of the nozzle flow path 20 is not limited to a circle, and may be a rectangle, for example. When the cross section of the flow path is not circular, the length of the first throat 213 is preferably 1.1 to 10 times the effective diameter of the first throat 213 (more preferably 1.5 to 2). Times or less). The same applies to the second throat 223 and the third throat 233. Thereby, it is possible to stably generate a large amount of fine bubbles while preventing the resistance generated in the fluid from becoming excessively large. Preferably, the effective diameter of the first throat 213 is equal to or less than the effective diameter of the second throat 223, and the effective diameter of the second throat 223 is equal to or less than the effective diameter of the third throat 233. Thereby, a large amount of fine bubbles can be generated more stably.

  For the fine bubble generating nozzle 2 shown in FIG. 3, under the above conditions relating to the inlet pressure P0, the size of each part of the nozzle flow path 20, etc., the structure having three throat parts has a structure having two throat parts, and Compared with the structure having four throats, a large amount of fine bubbles can be stably generated. In the fine bubble generating nozzle, the number of the plurality of throat portions provided in series in the nozzle flow path 20 may be variously changed in accordance with the change in conditions such as the inlet pressure P0. For example, the first tapered portion 212, the first throat portion 213, the first enlarged portion 221, the second tapered portion 222, and the second throat portion 223 are provided, and the second outlet 227 of the second throat portion 223 is provided. A fine bubble generating nozzle that ejects the fine bubble-containing liquid 73 from the target liquid 91 to the target liquid 91 may be used in the fine bubble generating device.

  In the pressurized liquid generating unit 3, if the gas supplied from the mixing nozzle 31 is completely dissolved in the liquid before reaching the pressurized liquid channel 4, the surplus gas separating unit 326 may be omitted. In the dissolution channel sections 32 and 32a, the five horizontal channels 321 to 325 do not necessarily have to be stacked in the vertical direction, and stepwise so that the mixed fluid flows in the same horizontal channel. It may be arranged. Moreover, the number of horizontal flow paths is not limited to five, and may be variously changed. However, by providing another channel through which the mixed fluid that has dropped from the horizontal channel to which the mixing nozzle 31 is attached, the amount of gas that is pressurized and dissolved in the liquid can be increased.

  The pressurized liquid generating unit is not limited to those having the above-described structure, and those having various structures may be used. For example, a pressurized tank that sprays liquid from the upper part of a pressurized tank and sends gas at the same time and performs pressure dissolution in the tank may be used as the pressurized liquid generating unit. In the above embodiment, the gas is sucked from the gas inlet 319 when the pressure in the nozzle flow path 310 in the gas mixing unit 316 is lower than the atmospheric pressure in the mixing nozzle 31. By connecting a cylinder or the like to 319, the gas may be supplied to the gas mixing unit 316 via the gas inlet 319 in a state where the pressure in the nozzle flow path 310 in the gas mixing unit 316 is equal to or higher than atmospheric pressure. .

  The above-mentioned fine bubble generating apparatus may be used for generating fine bubbles (so-called microbubbles) having a diameter of 1 μm or more and less than 1 mm. Also in this case, a large amount of microbubbles can be stably generated as in the above embodiment.

  The configurations in the above-described embodiments and modifications may be combined as appropriate as long as they do not contradict each other.

DESCRIPTION OF SYMBOLS 1, 1a, 1b Fine bubble production | generation apparatus 2, 2a-2d Fine bubble production | generation nozzle 3 Pressurization liquid production | generation part 4 Pressurization liquid flow path 5 Reservation part 20 Nozzle flow path 52 Inner surface 53 Hole part 61 Adjustment valve 62 Pressure sensor 63 Valve Control part 71 Pressure liquid 73 Fine bubble content liquid 212 1st taper part 213 1st throat part 217 1st outlet 221 1st enlarged part 221a (the 1st enlarged part) 1st surface 222 2nd taper part 223 2nd Throat 227 Second outlet 231 Second enlarged portion 231a (second enlarged portion) first surface 232 Third tapered portion 233 Third throat 237 Third outlet 251 First branch portion J2 (nozzle flow path) Central axis

Claims (9)

A fine bubble generating nozzle for generating a liquid containing fine bubbles from a pressurized liquid obtained by dissolving gas under pressure,
An upstream taper portion in which the channel area gradually decreases from the upstream side to the downstream side of the nozzle channel to which the pressurized liquid is supplied;
An upstream throat portion connected to a downstream end of the upstream taper portion, and ejecting fluid from the upstream taper portion from an upstream jet port;
An enlarged portion that connects to the upstream jet port and expands the flow path area;
Connected to the downstream end of the enlarged portion, a downstream taper portion where the flow path area gradually decreases from upstream to downstream, and
A downstream throat connected to the downstream end of the downstream taper and ejecting the fluid from the downstream taper from a downstream jet;
A fine bubble generating nozzle comprising: It is a fine bubble production | generation nozzle of Claim 1, Comprising:
The inner surface of the upstream taper portion and the inner surface of the downstream taper portion are each a part of a conical surface centered on the central axis of the nozzle channel,
In the cross section including the central axis, the angle formed by the inner surface of the upstream taper portion and the angle formed by the inner surface of the downstream taper portion are each 90 ° or less. The fine bubble generating nozzle according to claim 1 or 2,
The length of the upstream throat is 1.1 to 10 times the diameter of the upstream throat,
The length of the downstream throat is 1.1 to 10 times the diameter of the downstream throat. The fine bubble generating nozzle according to any one of claims 1 to 3,
The diameter of the downstream throat portion is equal to or larger than the diameter of the upstream throat portion. The fine bubble generating nozzle according to any one of claims 1 to 4,
In the cross section including the central axis of the nozzle flow path, an angle formed by a surface extending from the upstream jet port of the enlarged portion and the central axis is 45 ° or more and 90 ° or less, . The fine bubble generating nozzle according to any one of claims 1 to 5,
Another nozzle channel having the same structure as the nozzle channel;
A branching portion for branching the pressurized liquid into the nozzle channel and the another nozzle channel;
A fine bubble generating nozzle further comprising: A microbubble generator,
A fine bubble generating nozzle according to any one of claims 1 to 6,
A pressurized liquid generating unit that generates a pressurized liquid and supplies the pressurized liquid to the fine bubble generating nozzle;
A fine bubble generating apparatus comprising: It is a fine bubble production | generation apparatus of Claim 7, Comprising:
A pressurized liquid flow path connecting the pressurized liquid generating section and the fine bubble generating nozzle;
An adjustment valve that is provided in the pressure liquid flow path and adjusts the pressure of the pressure liquid in the pressure liquid flow path;
A pressure sensor for measuring the pressure in the pressurized liquid generating unit;
A valve control unit that controls the regulating valve based on an output from the pressure sensor;
A fine bubble generating apparatus, further comprising: A microbubble generator,
A fine bubble generating nozzle according to any one of claims 1 to 6,
A pressurized liquid generating unit that generates a pressurized liquid and supplies the pressurized liquid to the fine bubble generating nozzle;
A reservoir for storing a target liquid to which liquid generated by the fine bubble generating nozzle is supplied;
With
The downstream jet port of the fine bubble generating nozzle is the most downstream jet port of the nozzle channel;
A fine bubble generating device characterized in that an inner surface of the reservoir portion is provided with a hole that is recessed outward and is connected to the downstream jet port, and expands a flow passage area from the downstream jet port to the inner surface. .

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