JP5825852B2 - Fine bubble generating nozzle and fine bubble generating device - Google Patents

Description

  The present invention relates to a fine bubble generating nozzle that generates fine gas bubbles in a target liquid by ejecting a pressurized liquid in which the gas is dissolved under pressure into the target liquid, and a fine equipped with the fine bubble generating nozzle. The present invention relates to a bubble generating device.

  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. According to Patent Document 2, the cross-sectional area of the throat portion of the redistributor is preferably about 1.5 times the total cross-sectional area of the plurality of 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 that generates fine bubbles of the gas in the target liquid by ejecting a pressurized liquid in which the gas is dissolved under pressure into the target liquid, It has an inner surface which is part of a circle cone shall be the central axis of the nozzle passage, and a tapered portion flow path area is gradually reduced in the direction of flow of the pressurized liquid, a substantially cylindrical shape of the inner surface The nozzle and the tapered portion are connected to each other, and the throat portion having the smallest channel area in the nozzle channel and the periphery of the nozzle are separated from the nozzle. An enlarging part that enlarges the flow area of the pressurized liquid between the jet outlet and the target liquid by surrounding, the taper part, the throat part and the enlarging part are on the central axis An annular jet centered on the jet outlet is provided continuously. An end face of the mouth and a substantially cylindrical surface centered on the central axis, and an inner side surface forming an external flow path between the jet outlet end face and the enlarged portion opening provided at the end of the enlarged portion. An angle formed by the inner surface of the tapered portion is 90 ° or less, and a length of the throat portion is 1.1 times or more and 10 times or less of a diameter of the throat portion. There is .
The invention according to claim 2 is the fine bubble generating nozzle according to claim 1, wherein an angle formed between a tangent line passing through the center of the ejection port and in contact with the enlarged portion opening and the central axis is 14 .3 ° or more.
A third aspect of the present invention is the fine bubble generating nozzle according to the first or second aspect, wherein an angle formed by the end face of the jet outlet and the central axis is 90 °.

Invention of Claim 4 is the fine bubble production | generation nozzle in any one of Claim 1 thru | or 3 , Comprising: The branch part which branches a pressurized liquid into the said nozzle flow path and another nozzle flow path, The taper portion and the throat portion have the same structure, the taper portion and the throat portion forming another nozzle flow path, and the structure similar to the enlarged portion. And another enlarged portion that forms another external flow channel continuous with the one nozzle flow channel.

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

The invention according to claim 6 is the fine bubble generating device according to claim 5 , wherein the pressurized liquid generating unit mixes and ejects the gas and the liquid, and the mixing nozzle. The mixed fluid after being ejected flows in a pressurized environment, and the first fluid flow path where the mixed fluid immediately after being ejected from the mixing nozzle collides with the mixed fluid, and is positioned below the first fluid flow path. And a second flow path in which the mixed fluid dropped from the first flow path flows in a pressurized environment.

The invention according to claim 7 is the fine bubble generating device according to claim 5 or 6, and is provided in the connection pipe for connecting the pressurized liquid generation unit and the fine bubble generation nozzle, and the connection pipe. A regulating valve that adjusts the pressure of the pressurized liquid in the connection pipe, a pressure sensor that measures the pressure in the pressurized liquid generating section, and a valve that controls the regulating valve based on an output from the pressure sensor And a control unit.

  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 sectional drawing of another microbubble production | generation apparatus. It is an expanded sectional view of another fine bubble production | generation nozzle. It is sectional drawing of the fine bubble production | generation nozzle which concerns on 2nd Embodiment. It is sectional drawing which shows a part of other fine bubble production | generation apparatus. It is sectional drawing of the fine bubble production | generation nozzle which concerns on 3rd Embodiment. It is a front view of a fine bubble production | generation nozzle. It is a rear view of a fine bubble production | generation nozzle. It is a top view of the fine bubble production | generation nozzle which concerns on 4th Embodiment. It is a front view of a fine bubble production | generation nozzle. It is sectional drawing of a fine bubble production | generation nozzle.

  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, and a connection pipe 4. The connection pipe 4 connects the fine bubble generating nozzle 2 and the pressurized liquid generating unit 3. The pressurized liquid generating unit 3 generates a pressurized liquid 71 in which a gas is dissolved under pressure, and supplies the pressurized liquid 71 to the fine bubble generating nozzle 2 through the connection pipe 4. The fine bubble generating nozzle 2 generates the gas fine bubbles in the target liquid 92 by ejecting the pressurized liquid 71 into the target liquid 92 in the water tank 91. In the fine bubble generating apparatus 1 according to the present embodiment, air bubbles having a diameter of less than 1 μm are ejected by ejecting a pressurized liquid 71 obtained by pressurizing and dissolving air in water into a target liquid 92 that is water. (So-called nanobubbles) are generated in the target liquid 92. In FIG. 1, in order to facilitate understanding of the drawing, a parallel oblique line is given to the fluid such as the target liquid 92 by a broken line (the same applies to FIGS. 4 and 7).

  The pressurized liquid generating unit 3 includes a mixing nozzle 31 and a pressurized liquid generating container 32. In the pressurized liquid generating unit 3, the liquid (water in the present embodiment) pumped to the mixing nozzle 31 by a pump (not shown) and the gas sucked from the outside (air in the present embodiment) It is mixed by the mixing nozzle 31 and ejected toward the pressurized liquid generating container 32. The pressurized liquid generating container 32 is pressurized and 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 the fluid (hereinafter referred to as “mixed fluid 72”) flows in the pressurized liquid generating container 32 under 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 includes a liquid inlet 311 into which the liquid pumped by the above-mentioned pump flows in, a gas inlet 319 into which gas flows in, a liquid flowing in from the liquid inlet 311, and a gas flowing in from the gas inlet 319. A mixed fluid ejection port 312 is provided 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 part 313, a first taper part 314, a throat part 315, a gas mixing part 316, a second taper part 317, and the like, which are sequentially arranged from the liquid inlet 311 toward the mixed fluid outlet 312. A derivation unit 318 is 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 pressurized liquid generating container 32 via the mixed fluid ejection port 312.

  As shown in FIG. 1, the pressurized liquid generation container 32 includes a first flow path 321, a second flow path 322, a third flow path 323, a fourth flow path 324, and a fifth flow path 325 that are stacked in the vertical direction. Is provided. In the following description, the first flow path 321, the second flow path 322, the third flow path 323, the fourth flow path 324, and the fifth flow path 325 are collectively referred to as “flow paths 321 to 325”. The flow paths 321 to 325 are pipelines extending in the horizontal direction, and the cross section perpendicular to the longitudinal direction of the flow paths 321 to 325 is substantially rectangular. In the present embodiment, the width of the flow paths 321 to 325 is about 40 mm.

  The mixing nozzle 31 is attached to the upstream end portion of the first flow path 321 (that is, the left end portion in FIG. 1), and the mixed fluid 72 after being ejected from the mixing nozzle 31 is added. It flows toward the right side in FIG. 1 under a pressure 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 flow path 321, and the wall surface on the downstream side of the first flow path 321. Before colliding with (that is, the right wall surface in FIG. 1), it directly collides with the liquid surface. 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 flow path 321 is set to the center of the mixed fluid ejection port 312 (see FIG. 2) of the mixing nozzle 31 and the first. It is preferable to make it larger than 7.5 times the vertical distance between the lower surface of the channel 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 flow path 321. As a result, in the same manner as described above, the mixed fluid 72 immediately after being ejected from the mixing nozzle 31 directly collides with the mixed fluid 72 flowing in the first channel 321 in the first channel 321.

  A substantially circular opening 321 a is provided on the lower surface of the downstream end portion of the first flow path 321, and the mixed fluid 72 flowing through the first flow path 321 is located below the first flow path 321. It falls to the two flow paths 322 through the opening 321a. In the second flow path 322, the mixed fluid 72 that has dropped from the first flow path 321 flows from the right side to the left side in FIG. 1 in a pressurized environment, and on the lower surface of the downstream end of the second flow path 322. The liquid drops to the third flow path 323 located below the second flow path 322 through the provided substantially circular opening 322a. In the third flow path 323, the mixed fluid 72 dropped from the second flow path 322 flows from the left side to the right side in FIG. 1 in a pressurized environment, and on the lower surface of the downstream end of the third flow path 323. It drops to the fourth flow path 324 located below the third flow path 323 through the provided substantially circular opening 323a. As shown in FIG. 1, in the first flow path 321 to the fourth flow path 324, the mixed fluid 72 is divided into a liquid layer containing bubbles and a gas layer located thereabove.

  In the fourth flow path 324, the mixed fluid 72 dropped from the third flow path 323 flows from the right side to the left side in FIG. 1 in a pressurized environment, and on the lower surface of the downstream end portion of the fourth flow path 324. It flows (i.e., falls) into the fifth flow path 325 located below the fourth flow path 324 through the provided substantially circular opening 324a. In the fifth channel 325, unlike the first channel 321 to the fourth channel 324, there is no gas layer, and the fifth channel 325 is in the liquid that fills the fifth channel 325. There are slight bubbles in the vicinity of the upper surface. In the fifth flow path 325, the mixed fluid 72 flowing in from the fourth flow path 324 flows from the left side to the right side in FIG.

  In the pressurization liquid production | generation part 3, the flow paths 321-325 of the pressurization liquid production | generation container 32 flow down from top to bottom, repeating steps gradually (namely, the flow in a horizontal direction and the flow in a downward direction). In the mixed fluid 72 (flowing alternately and repeatedly), the gas is gradually dissolved in the liquid under pressure. In the fifth 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 was not melt | dissolved in the liquid exists in the 5th flow path 325 as a bubble of the magnitude | size which can be visually recognized.

The pressurized liquid generation container 32 further includes a surplus gas separation unit 326 extending upward from the upper surface on the downstream side of the fifth flow path 325, and the surplus gas separation unit 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 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. It is sent out to the connecting pipe 4 connected to the end (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 flow paths 321 to 325 in the pressurized liquid generation container 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 51, a pressure sensor 52, and a valve control unit 53. The adjustment valve 51 is provided in the connection pipe 4 and adjusts the pressure of the pressurized liquid 71 in the connection pipe 4. The pressure sensor 52 is disposed above the first flow path 321 and measures the pressure in the pressurized liquid generating container 32 of the pressurized liquid generating unit 3. An exhaust valve 61 is also provided above the first flow path 321. In the fine bubble generating device 1, the measured value of the pressure in the pressurized liquid generating container 32 output from the pressure sensor 52 is set to a predetermined pressure (preferably 0.1 MPa to 0.45 MPa). Further, the regulating valve 51 is controlled by the valve control unit 53. In other words, the valve control unit 53 controls the adjustment valve 51 based on the output from the pressure sensor 52. The pressurized liquid 71 that has passed through the connection pipe 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 pressurized liquid inlet 21 through which the pressurized liquid 71 flows from the connection pipe 4 and a pressurized liquid outlet 22 that opens toward the target liquid 92. The pressurized liquid inlet 21 and the pressurized liquid outlet 22 are each substantially circular, and the cross section of the nozzle flow path 20 from the pressurized liquid inlet 21 toward the pressurized liquid outlet 22 is also substantially circular.

  The fine bubble generating nozzle 2 includes an introduction part 23, a taper part 24, and a throat part 25 that are sequentially arranged from the pressurized liquid inlet 21 toward the pressurized liquid outlet 22. In the introduction portion 23, the flow channel area is substantially constant at each position in the direction of the central axis J <b> 2 of the nozzle flow channel 20. In the taper portion 24, the flow path area gradually decreases in the direction in which the pressurized liquid 71 (see FIG. 1) flows (that is, toward the downstream side). The inner surface of the tapered portion 24 is a part of a substantially conical surface with the central axis J2 of the nozzle channel 20 as the center. In the cross section including the central axis J2, the angle α formed by the inner surface of the tapered portion 24 is preferably 10 ° or more and 90 ° or less.

  The throat part 25 connects the taper part 24 and the pressurized liquid ejection port 22. The inner surface of the throat portion 25 is a substantially cylindrical surface, and the flow path area is substantially constant in the throat portion 25. The diameter of the channel cross section in the throat 25 is the smallest in the nozzle channel 20, and the channel area of the throat 25 is the smallest in the nozzle channel 20. The length of the throat 25 is preferably 1.1 to 10 times the diameter of the throat 25, and more preferably 1.5 to 2 times. In the nozzle channel 20, even if the channel area slightly changes in the throat portion 25, the entire portion having the smallest channel area is regarded as the throat portion 25.

  The fine bubble generating nozzle 2 is also provided continuously to the throat portion 25 and encloses the periphery of the pressurizing liquid jet port 22 away from the pressurizing liquid jet port 22, and the end of the enlarging unit 27 An enlarged portion opening 28 provided in the portion is provided. The flow path 29 between the pressurized liquid jet port 22 and the enlarged portion opening 28 is a flow path provided outside the pressurized liquid jet port 22 and is hereinafter referred to as an “external flow path 29”. The channel cross section of the external channel 29 and the enlarged portion opening 28 are substantially circular, and the channel area of the external channel 29 is substantially constant. The diameter of the external flow path 29 is larger than the diameter of the throat portion 25 (that is, the diameter of the pressurized liquid ejection port 22). In the following description, an annular surface between the edge of the inner peripheral surface of the enlarged portion 27 on the side of the pressurized liquid jet port 22 and the edge of the pressurized liquid jet port 22 is referred to as a “jet port end surface 221”. In the present embodiment, the angle formed by the central axis J2 of the nozzle flow path 20 and the external flow path 29 and the jet end face 221 is about 90 °. The diameter of the external channel 29 is 10 mm to 20 mm, and the length of the external channel 29 is approximately equal to the diameter of the external channel 29. In the fine bubble generating nozzle 2, an external channel 29 that is a recess is formed at the end opposite to the pressurizing liquid inlet 21, and the pressurizing liquid that is an opening smaller than the bottom at the bottom of the recess. It can be understood that the spout 22 is formed. In the enlargement unit 27, the flow path area of the pressurized liquid 71 between the pressurized liquid ejection port 22 and the target liquid 92 in the water tank 91 is enlarged.

  In the fine bubble generating nozzle 2, the pressurized liquid 71 that has flowed into the nozzle flow path 20 from the pressurized liquid inlet 21 flows to the throat part 25 while being gradually accelerated in the tapered part 24, and passes through the throat part 25. It is ejected as a jet from the pressurized liquid ejection port 22. The flow rate of the pressurizing liquid 71 in the throat 25 is preferably 10 m to 30 m per second, and in this embodiment is about 20 m per second. In the throat 25, the static pressure of the pressurized liquid 71 is reduced, so that the gas in the pressurized liquid 71 becomes supersaturated and precipitates in the liquid as fine bubbles. The fine bubbles pass through the external flow path 29 of the enlarged portion 27 together with the pressurized liquid 71 and diffuse into the target liquid 92 in the water tank 91. In the fine bubble generating nozzle 2, the fine bubbles are deposited while the pressurized liquid 71 passes through the external flow path 29. The fine bubbles generated by the fine bubble generating nozzle 2 are so-called nano bubbles having a diameter of less than 1 μm. When the ejection of the liquid and the fine bubbles from the fine bubble generating nozzle 2 is stopped, the external flow path 29 is filled with the target liquid 92.

As described above, in the fine bubble generating nozzle 2, the tapered portion 24 in which the flow passage area gradually decreases in the direction in which the pressurized liquid 71 flows, and the throat portion in which the flow passage area is the smallest in the nozzle flow passage 20. By providing 25, it is possible to stably generate a large amount of fine bubbles, particularly fine bubbles (nanobubbles) having a diameter of less than 1 μm. According to the measurement by Nippon Kantam Design Co., Ltd. nanosite, the nanobubbles distributed in the range of less than 1 μm centered on about 100 nm by the fine bubble generation nozzle 2 are 100 million to 200 million in the target liquid 92 of 1 cm ^3. About one is generated. In the following description, the number of nanobubbles generated by the fine bubble generating nozzle 2 in the 1 cm ³ target liquid 92 is referred to as “nanobubble generation density”.

  In the fine bubble generating nozzle 2, the enlarged portion 27 surrounding the periphery of the pressurized liquid ejection port 22 is provided, so that the flow of the target liquid 92 in the water tank 91 is added immediately after being ejected from the pressurized liquid ejection port 22. An influence on the pressure fluid 71 can be suppressed. Thereby, also in the pressurizing liquid 71 immediately after jetting from the pressurizing liquid jet port 22, nanobubbles are deposited stably, so that a large amount of nanobubbles can be generated more stably.

  As described above, in the fine bubble generating nozzle 2, the inner surface of the tapered portion 24 is a part of a conical surface centered on the central axis J <b> 2 of the nozzle flow path 20, and the tapered portion 24 in the cross section including the central axis J <b> 2. The angle α formed by the inner surface is 90 ° or less. Thereby, a large amount of nanobubbles can be generated more stably. Further, from the viewpoint of shortening the length of the fine bubble generating nozzle 2 while maintaining the diameters of the introduction portion 23 and the throat portion 25 of the fine bubble generating nozzle 2, the angle α formed by the inner surface of the tapered portion 24 is 10 ° or more. It is preferable that

  In the fine bubble generating nozzle 2, the length of the throat portion 25 is 1.1 to 10 times the diameter of the throat portion 25. When the length of the throat part 25 is 1.1 times or more of the diameter, a large amount of nanobubbles can be generated more stably. For example, when the length of the throat 25 is 0.53 times the diameter, the generation density of nanobubbles is about 56 million, whereas the length of the throat 25 is 1.57 times the diameter. The generation density of nanobubbles is about 11 million. Further, since the length of the throat portion 25 is 10 times or less of the diameter, it is possible to prevent the resistance generated in the pressurized liquid 71 in the throat portion 25 from becoming excessively large, and the high accuracy of the throat portion 25. Can be easily formed. From the viewpoint of more stably generating a large amount of nanobubbles, it is more preferable that the length of the throat portion 25 is 1.5 to 2 times the diameter.

  In the fine bubble generating device 1 shown in FIG. 1, when the fine bubble generation is stopped, the driving of the pump that pumps the liquid to the mixing nozzle 31 of the pressurized liquid generating unit 3 is stopped. The exhaust valve 61 is opened until the liquid flow from the pump to the mixing nozzle 31 stops. Thereby, the pressurized gas in the pressurized liquid generating container 32 is released to the outside through the exhaust valve 61. As a result, it is possible to prevent the liquid from flowing back to the mixing nozzle 31 and the pump due to the expansion of the gas in the pressurized liquid generating container 32.

  FIG. 4 is a view showing another preferred arrangement of the regulating valve 51 provided in the connection pipe 4. In the fine bubble generating device 1, the connection pipe 4 includes a main pipe 41 that connects the pressurized liquid generating container 32 and the fine bubble generating nozzle 2, and a branch pipe 42 that is connected to the main pipe 41. It is provided in the branch pipe 42 of the pipe 4. Also in this case, similarly to the above, the pressure in the pressurized liquid generating container 32 is set to a predetermined value by controlling the adjustment valve 51 based on the output from the pressure sensor 52 by the valve control unit 53. Pressure.

In the fine bubble generating nozzle 2 described above, the inner side surface of the enlarged portion 27 is a substantially cylindrical surface centered on the central axis J2 of the external flow path 29. However, in the technology related to the present invention, other shapes are used. Also good. FIG. 5 is a cross-sectional view showing the fine bubble generating nozzle 2 according to the related art, and corresponds to FIG. 3 described above. As shown in FIG. 5, in the fine bubble generating nozzle 2, the inner surface of the enlarged portion 27 is a part of a substantially conical surface centered on the central axis J <b> 2 of the external flow channel 29. The area gradually increases with distance from the pressurized liquid jet port 22. In the example shown in FIG. 5, in the cross section including the central axis J2 of the external flow path 29, the angle β formed between the tangent line 272 that is in contact with the enlarged portion 27 through the center of the pressurized liquid ejection port 22 and the central axis J2 is , Approximately 45 °.

  The inner side surface of the external channel 29 may have a shape other than a substantially cylindrical surface or a substantially conical surface. However, the above-mentioned angle β is preferably 14.3 ° or more. Thereby, the influence which the inner surface of the external flow path 29 has with respect to the jet of the pressurizing liquid 71 ejected from the pressurizing liquid spout 22 can be reduced, and a large amount of nanobubbles can be generated more stably. be able to.

  Next, a microbubble generator according to a second embodiment of the present invention will be described. In the fine bubble generating apparatus according to the second embodiment, a fine bubble generating nozzle 2a shown in FIG. 6 is provided 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 FIG. 6, the fine bubble generating nozzle 2 a includes an introduction part 23, a branch part 231, and two sets of a taper part 24, a throat part 25, and an enlarged part 27. The two sets of the taper portion 24, the throat portion 25, and the enlarged portion 27 have the same structure. In the fine bubble generating nozzle 2 a, one nozzle flow path 20 is formed by one set of taper portion 24 and throat portion 25, and the other set of taper portion 24 and throat portion 25 extends in parallel to the nozzle flow path 20. Another nozzle channel 20 is formed. Further, an external flow path 29 is formed by one enlarged portion 27, and another external flow path 29 is formed by another enlarged portion 27. The shapes of the nozzle channels 20 and the external channels 29 are the same as those in the first embodiment.

  In the fine bubble generating nozzle 2a, the pressurized liquid 71 (see FIG. 1) flowing in from the connection pipe 4 passes through the common flow path 232 of the introducing portion 23 and is provided on the central axis J3 of the fine bubble generating nozzle 2a. The branched portion 231 branches into two nozzle channels 20. In each nozzle channel 20, fine bubbles are deposited from the pressurized liquid 71 at the throat 25, and are ejected together with the pressurized liquid 71 from the pressurized liquid ejection port 22 of each nozzle channel 20. Then, it passes through the external flow path 29 of the enlarged portion 27 and diffuses into the target liquid 92 (see FIG. 1). In the fine bubble generating nozzle 2a, the pressurized liquid 71 is ejected from the two pressurized liquid ejection ports 22 in the same direction.

  In the fine bubble generating nozzle 2a, by providing a plurality of nozzle flow paths 20 and a plurality of pressurized liquid ejection ports 22, the diameter of each pressurized liquid ejection port 22 is not increased or an increase in diameter is suppressed. Meanwhile, the supply amount of the pressurized liquid 71 to the target liquid 92 can be increased. Thereby, increase of the force added to the fine bubble production | generation nozzle 2a by ejection of the pressurized liquid 71 can be suppressed. Moreover, the enlargement of the water tank 91 (refer FIG. 1) and the fine bubble production | generation apparatus can be suppressed. Thus, by using the fine bubble generating nozzle 2a, it is possible to easily cope with a change in the flow rate of the pressurized liquid 71, that is, a change in the supply amount of the fine bubbles.

  In the fine bubble generating nozzle 2 a, the gas is dissolved in the pressurizing liquid 71 on the upstream side of the branching portion 231, and exists uniformly in the pressurizing liquid 71. Therefore, it is possible to prevent the gas from being biased to any one of the nozzle channels 20 when branching to the plurality of nozzle channels 20 by the branch portion 231. As a result, the amount of fine bubbles ejected from the plurality of pressurized liquid ejection ports 22 can be made uniform.

  FIG. 7 is a cross-sectional view showing a part of the fine bubble generating device 1a provided with two fine bubble generating nozzles 2a. As shown in FIG. 7, in the fine bubble generating device 1 a, the connection pipe 4 is branched into two pipes 43, and the fine bubble generating nozzle 2 a is provided at the tip of each pipe 43. In the fine bubble generating device 1 a, the gas is dissolved in the pressurized liquid 71 in the connection pipe 4 and is present uniformly in the pressurized liquid 71. Therefore, when branching to the plurality of pipes 43, the gas is prevented from being biased to any one of the pipes 43. As a result, the amount of fine bubbles ejected from the plurality of fine bubble generating nozzles 2a can be made uniform.

  Next, a microbubble generator according to a third embodiment of the present invention will be described. FIG. 8 is a cross-sectional view of the fine bubble generating nozzle 2b of the fine bubble generating apparatus according to the third embodiment. 9 is a front view of the fine bubble generating nozzle 2b as viewed from the enlarged portion opening 28 side, and FIG. 10 is a rear view of the fine bubble generating nozzle 2b as viewed from the pressurized liquid inlet 21 side. In the fine bubble generating apparatus according to the third embodiment, a fine bubble generating nozzle 2b shown in FIGS. 8 to 10 is provided 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. 8 to 10, the fine bubble generating nozzle 2 b includes an introduction part 23, a branch part 231, and six sets of a taper part 24, a throat part 25, and an enlargement part 27. The six sets of the taper portion 24, the throat portion 25, and the enlarged portion 27 have the same structure. In the fine bubble generating nozzle 2 b, six nozzle channels 20 extending in parallel with each other are formed by the six sets of taper portions 24 and throat portions 25, and six external channels 29 are formed by the six enlarged portions 27. The branching portion 231 has a conical shape centered on the central axis J4 of the fine bubble generating nozzle 2b, and the apex faces the pressurized liquid inlet 21. The six sets of nozzle flow paths 20 and the external flow paths 29 are arranged circumferentially around the central axis J4 of the fine bubble generating nozzle 2b, for example, at equal intervals. The shapes of the nozzle channels 20 and the external channels 29 are the same as those in the first embodiment.

  In the fine bubble generating nozzle 2 b, the pressurized liquid 71 that has flowed in from the connection pipe 4 passes through the common flow path 232 of the introduction part 23 and branches into six nozzle flow paths 20 by the branching part 231. In each nozzle channel 20, fine bubbles are deposited from the pressurized liquid 71 at the throat 25, and are ejected together with the pressurized liquid 71 from the pressurized liquid ejection port 22 of each nozzle channel 20. Then, it passes through the external flow path 29 of the enlarged portion 27 and diffuses into the target liquid 92. In the fine bubble generating nozzle 2b, the pressurized liquid 71 is ejected from the six pressurized liquid ejection ports 22 in the same direction.

  In the fine bubble generating nozzle 2b, by providing a plurality of nozzle flow paths 20 and a plurality of pressurized liquid ejection ports 22, as with the fine bubble generating nozzle 2a (see FIG. 6), the flow rate of the pressurized liquid 71 is changed. That is, it is possible to easily cope with a change in the supply amount of fine bubbles. Further, the amount of fine bubbles ejected from the plurality of pressurized liquid ejection ports 22 can be made uniform.

  Next, a microbubble generator according to a fourth embodiment of the present invention will be described. FIGS. 11 and 12 are a plan view and a front view, respectively, of the fine bubble generating nozzle 2c of the fine bubble generating device according to the fourth embodiment. FIG. 13 is a cross-sectional view of the fine bubble generating nozzle 2c cut at the position AA in FIG. In the fine bubble generating apparatus according to the fourth embodiment, a fine bubble generating nozzle 2c shown in FIGS. 11 to 13 is provided instead of the fine bubble generating nozzle 2 shown in FIG. Further, the fine bubble generating nozzle 2 c is submerged in the target liquid 92 from the upper opening of the water tank 91 in a state where the connection pipe 4 for supplying the pressurized liquid 71 is connected to the upper end of the fine bubble generating nozzle 2 c. 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. 11 to 13, the fine bubble generating nozzle 2 c includes an introduction part 23, four branch parts 231, and four sets of a taper part 24, a throat part 25, and an enlarged part 27. The four sets of the taper portion 24, the throat portion 25, and the enlarged portion 27 have the same structure. In the fine bubble generating nozzle 2 c, four nozzle channels 20 are formed by the four sets of taper portions 24 and throat portions 25, and four external channels 29 are formed by the four enlarged portions 27. The shapes of the nozzle channels 20 and the external channels 29 are the same as those in the first embodiment. The four sets of nozzle flow paths 20 and external flow paths 29 are arranged radially about the central axis J5 of the common flow path 232 of the introduction portion 23 extending in the vertical direction. The angle formed by the central axis J2 of each of the two adjacent nozzle channels 20 is 90 °. The four branch portions 231 are arranged between the two adjacent taper portions 24 on the circumference around the central axis J5 of the common flow path 232.

  In the fine bubble generating nozzle 2 c, the pressurized liquid 71 that has flowed in from the connection pipe 4 passes through the common flow path 232 of the introduction part 23 and branches into the four nozzle flow paths 20 by the four branch parts 231. In each nozzle channel 20, fine bubbles are deposited from the pressurized liquid 71 at the throat 25, and are ejected together with the pressurized liquid 71 from the pressurized liquid ejection port 22 of each nozzle channel 20. Then, it passes through the external flow path 29 of the enlarged portion 27 and diffuses into the target liquid 92. In the fine bubble generating nozzle 2c, the pressurized liquid 71 is ejected radially from the four pressurized liquid ejection ports 22 in the horizontal direction.

  In the fine bubble generating nozzle 2c, by providing a plurality of nozzle channels 20 and a plurality of pressurized liquid ejection ports 22, as with the fine bubble generating nozzle 2a (see FIG. 6), the flow rate of the pressurized liquid 71 is changed. That is, it is possible to easily cope with a change in the supply amount of fine bubbles. Further, the amount of fine bubbles ejected from the plurality of pressurized liquid ejection ports 22 can be made uniform.

  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 according to the related art of the present invention, the inner surface of the taper portion 24 does not necessarily need to be a part of a substantially conical surface. For example, the inner surface of the taper portion 24 is convex inward from the substantially conical surface. It may be a curved surface that swells in a concave shape or a curved surface that swells in a concave shape outside the substantially conical surface. In addition, if the fine bubble generating nozzle is arranged so that the pressurized liquid 71 immediately after being ejected from the pressurized liquid ejection port 22 is not significantly affected by the flow of the target liquid 92 in the water tank 91, the The enlargement unit 27 may be omitted from the bubble generation nozzle.

  In the pressurized liquid generation unit 3, if the gas supplied from the mixing nozzle 31 is completely dissolved in the liquid before reaching the connection pipe 4, the surplus gas separation unit 326 may be omitted. In the pressurized liquid generating container 32, the five flow paths 321 to 325 are not necessarily stacked in the vertical direction, and are arranged in a stepped manner so that the mixed fluid flows in the same flow path in the same flow direction. Also good. Further, the number of flow paths is not limited to five, and may be variously changed. However, by providing another flow path for the mixed fluid that has fallen from the flow path 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 Fine bubble production | generation apparatus 2,2a-2c Fine bubble production | generation nozzle 3 Pressurization liquid production | generation part 4 Connection piping 20 Nozzle flow path 22 Pressurization liquid ejection outlet 24 Taper part 25 Throat part 27 Expansion part 31 Mixing nozzle 51 Adjustment valve 52 Pressure Sensor 53 Valve Control Unit 71 Pressurized Liquid 72 Mixed Fluid 92 Target Liquid 231 Branching Section 272 Tangent 321 First Channel 322 Second Channel 323 Third Channel 324 Fourth Channel 325 Fifth Channel J2 Central Axis

Claims (7)

A fine bubble generating nozzle that generates fine bubbles of the gas in the target liquid by ejecting a pressurized liquid in which the gas is dissolved under pressure, into the target liquid,
A tapered portion having an inner surface which is part of a circle cone shall be the central axis of the nozzle channel, the flow passage area in the direction of flow of the pressurized liquid gradually decreased,
An inner surface having a substantially cylindrical surface shape, communicating the jet opening opening toward the target liquid and the tapered portion, and the throat portion having the smallest channel area in the nozzle channel;
Enlarging the flow passage area of the pressurized liquid between the jet outlet and the target liquid by surrounding the jet outlet apart from the jet outlet,
With
The tapered portion, the throat portion, and the enlarged portion are provided continuously on the central axis,
The inner surface of the enlarged portion is
An annular spout end face centering on the spout;
An inner surface that forms an external flow path between the end face of the ejection port and an enlarged portion opening provided at an end of the enlarged portion;
Equipped with a,
In a cross section including the central axis, an angle formed by the inner surface of the tapered portion is 90 ° or less,
The length of the throat is 1.1 to 10 times the diameter of the throat . It is a fine bubble production | generation nozzle of Claim 1, Comprising:
The fine bubble generating nozzle, wherein an angle formed between a tangent line passing through the center of the jet port and in contact with the opening of the enlarged portion and the central axis is 14.3 ° or more. The fine bubble generating nozzle according to claim 1 or 2,
The fine bubble generating nozzle, wherein an angle formed between the end face of the jet port and the central axis is 90 °. The fine bubble generating nozzle according to any one of claims 1 to 3 ,
A branching portion for branching the pressurized liquid into the nozzle channel and another nozzle channel;
Another set of taper and throat having the same structure as the taper and throat, and forming the another nozzle channel;
Another enlarged portion having the same structure as the enlarged portion and forming another external flow channel continuous with the other nozzle flow channel;
A fine bubble generating nozzle further comprising: A microbubble generator,
A fine bubble generating nozzle according to any one of claims 1 to 4 ,
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 5 , Comprising:
The pressurizing liquid generator is
A mixing nozzle for mixing and ejecting the gas and the liquid;
A first flow path in which the mixed fluid after being ejected from the mixing nozzle flows in a pressurized environment, and the mixed fluid immediately after being ejected from the mixing nozzle collides with the mixed fluid;
A second channel that is located below the first channel and in which the mixed fluid dropped from the first channel flows in a pressurized environment;
A fine bubble generating apparatus comprising: It is a fine bubble production | generation apparatus of Claim 5 or 6 ,
A connection pipe for connecting the pressurized liquid generating unit and the fine bubble generating nozzle;
An adjustment valve that is provided in the connection pipe and adjusts the pressure of the pressurized liquid in the connection pipe;
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:

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