JP6691716B2 - Method and device for generating fine bubbles - Google Patents

Description

  The present invention relates to a method and apparatus for generating fine bubbles, and more particularly to a method and apparatus for generating fine bubbles using an ejector.

  For the purpose of improving / improving the water quality, fine bubbles may be supplied to water in aquaculture ponds of seafood, closed water areas of lakes / marshes / rivers / lakes, wastewater treatment plants, sewage treatment plants, etc. (See Patent Documents 1 and 2). The fine bubbles are fine bubbles having a particle size of 100 μm or less (for example, several tens of μm to several μm), which are also called fine bubbles, microbubbles, or nanobubbles, and are not found in ordinary bubbles (for example, bubbles having a particle size of 1 mm or more). For example, it has a small buoyancy and floats in water for a long time to reach various parts, and also has a feature that it floats in water and shrinks and disappears (completely dissolves).

  By supplying the fine bubbles to water and completely dissolving them, for example, it is expected that the dissolved oxygen concentration in various parts of the water can be efficiently increased and the water quality can be improved and improved. It has also been reported that water containing fine bubbles has an active effect on microorganisms, plants, and animals, and can be used, for example, to increase the yield of eggplants, tomatoes, and the like (see Non-Patent Document 1). Further, in the fields of pharmaceuticals and foods, fine gas bubbles containing various gases (oxygen, ozone, nitrogen, etc.) are used. For example, it is recognized that fine gas bubbles containing ozone gas have a strong bactericidal effect. ing.

  An example of a conventional method for supplying fine bubbles to water (in liquid) is to pass the liquid through a small-diameter pipe of an ejector at high speed, and use the negative pressure generated by the liquid flow from the gas phase Pa to the liquid phase Pb. The gas is sucked (self-sucking), and the sucked gas is finely crushed by the cavitation generated by the expansion of the downstream pipeline to generate fine bubbles (see Non-Patent Document 2). For example, as shown in FIG. 6A, a fine bubble generator 60 using an ejector 62 (hereinafter sometimes referred to as an ejector type fine bubble generator) has a pump 63 in a liquid phase Pb in a liquid storage tank 61. The ejector 62 is arranged, and the pressurized liquid Q sucked by the pump 63 is circulated to the ejector 62 via the liquid flow path 64 and the flow rate adjusting valve 65. Further, one end of the gas supply passage 66 is connected to the ejector 62, and the opening / closing cock 67 at the other end of the gas supply passage 66 is arranged in communication with the gas phase Pa (see Patent Document 1).

  FIG. 6B shows a cross-sectional view of an example of the ejector 62. The ejector 62 of the illustrated example has a hollow portion 62a that takes in the pressurized liquid Q from the liquid flow path 64, and an enlarged diameter inlet (pipe line inlet) 62b is provided on the upstream side of the hollow portion 62a so that the cross section is substantially T-shaped. In addition, a fine intake hole 62e is provided in the middle portion (small-diameter conduit) of the conduit whose diameter is smaller than that of the inlet to connect one end of the gas supply passage 66. The pressurized liquid Q flowing in from the pipe inlet 62b produces a negative pressure when passing through the small-diameter pipe, and the gas G is sucked from the gas supply passage 66 through the fine suction holes 62e and mixed with the liquid. The mixed gas G is sent to the conduit outlet 62c together with the pressurized liquid Q, finely crushed by the cavitation generated by the expansion of the outlet conduit, and released as fine bubbles S.

  FIG. 6C shows a cross-sectional view of another example of the ejector (venturi) 62 in which a reduced diameter portion (small diameter conduit) 62d is provided in the middle portion of the hollow conduit 62a. The ejector 62 of the illustrated example is provided with a fine suction hole 62e for connecting one end of the gas supply passage 66 to the reduced diameter portion 62d, and when the pressurized liquid Q flowing from the conduit inlet 62b passes through the reduced diameter portion 62d. A negative pressure is generated in the gas, and the gas G is sucked from the gas supply path 66 through the fine intake holes 62e and mixed with the liquid. The gas G mixed with the pressurized liquid Q is crushed by the cavitation generated by the expansion of the pipeline on the downstream side, and becomes fine bubbles S and is discharged from the pipeline outlet 62c.

JP, 2005-334869, A JP, 2006-167612, A

Himuro Shozo "Fundamental of Fine Bubbles and Its Applications" Science Material No. 80, Jikkyo Shuppan, September 26, 2016, Internet <http: // www. jikkyo. co. jp / download / detail / 45/99992657592> Fine Bubble Society Association, Koichi Terasaka et al., "Introduction to Fine Bubbles, Chapter 6, Fine Bubble Generation Technology," Nikkan Kogyo Shimbun, November 28, 2016, pp. 167-192

  However, the conventional ejector-type micro-bubble generator 60 shown in FIG. 6 has a problem that the micro-intake holes 62e of the ejector 62 may be blocked by, for example, suspended matter contained in the pressurized liquid Q. The blockage of the fine intake holes 62e can occur not only by the suspended matter in the pressurized liquid Q but also by metal corrosion (for example, local corrosion of stainless steel) or the like. For example, in a fish farm or a closed water area, it is often necessary to continue the supply of fine bubbles for a long period of time, but when the fine intake holes 62 are closed, the suction of the gas G stops and the generation of the fine bubbles S stops, so unmanned When the ejector type fine bubble generator 60 is used in the fish farm, the ocean, etc., another measure is required to prevent the generation of the fine bubbles S. In order to utilize the fine bubbles S in an unmanned ocean or fish farm, it is difficult to stop the suction of the gas G, and an ejector-type fine bubble generator capable of stably supplying the fine bubbles S even when continuously used for a long period of time. Development is desired.

  Therefore, an object of the present invention is to provide an ejector type fine bubble generating method and device capable of continuously supplying fine bubbles for a long period of time.

Referring to the embodiment of FIGS . 1 and 2, in the method for generating fine bubbles according to the present invention, the inlet 12 and the outlet 13 have a predetermined inner diameter R1 and a reduced diameter portion 14 is formed on an inner peripheral surface 15a of a predetermined depth portion L1. uneven inner peripheral surface 15a of the hollow outer tube exit side wall 15 on the exit side wall 15 inner circumferential surface 15a vent hole 16 that the outlet-side wall 15 with one puncture a stocked a central axis I in a tangential direction of the 10 2B, the outer diameter R3 is smaller than the predetermined inner diameter R1 of the hollow outer tube 10 and the inner diameter R2 is the same as the reduced diameter portion 14, and the outer peripheral surface 25b of the predetermined depth portion L2 is smaller than the predetermined inner diameter R1. and larger one end 22 of hollow tube 20 flange 24 is formed with an outer diameter of R0 to fit the core to the outlet 13 of the hollow outer tube 10 plugged write Mutotomoni insertion end curved no unevenness of the outer peripheral surface 25b (FIG. 1 (A) arrow B and FIG. 2 (B) ), middle The flange 24 of the hollow inner pipe 20 is fixed around the outlet 13 of the outer pipe 10, and the insertion end 22 of the hollow inner pipe 20 is formed with the reduced diameter portion 14 of the hollow outer pipe 10 (= L1-L2). The pressurizing liquid Q is introduced from the inlet 12 while being opposed to each other (see FIGS. 1B and 2A ) and communicating the vent hole 16 of the hollow outer tube 10 with the gas phase Pa (see FIG. 6). The hollow inner tube 20 is formed between the hollow outer tube 10 and the hollow inner tube 20 from the gas phase Pa through the pores 16 and the minute gap E, and the annular inner surface having no unevenness and the minute gap E. The gas G is sucked in and the sucked gas G is discharged from the other end 23 of the hollow inner tube 20 while being crushed.

Further, referring to the embodiments of FIGS . 1 and 2, in the fine bubble generator according to the present invention, the inlet 12 and the outlet 13 have a predetermined inner diameter R1 and a reduced diameter portion 14 is formed on the inner peripheral surface 15a of the predetermined depth portion L1. It is and the outlet-side peripheral wall 15 an outlet side wall 15 inner circumferential surface 15a tangentially without irregularities to the inner peripheral surface 15a of the exit-side wall 15 of the vent holes 16 which align a central axis I with one puncture the curved surface of the to ( 2B), the outer diameter R3 smaller than the predetermined inner diameter R1 of the hollow outer tube 10 and the same inner diameter R2 as the reduced diameter portion 14 and the predetermined inner diameter R1 on the outer peripheral surface 25b of the predetermined depth portion L2. A flange 24 having a larger outer diameter R0 is formed, and one end 22 is inserted into the outlet 13 of the hollow outer tube 10 with its center aligned, and the outer peripheral surface 25b of the insertion end is a curved surface without unevenness (see FIG. 2B). Hollow inner tube 20 and hollow outer tube 1 A fixing member 30 for fixing the flange 24 of the hollow inner pipe 20 is provided around the outlet 13 of the hollow inner pipe 20, and the forming end L2 of the flange 24 of the hollow inner pipe 20 is inserted into the hollow outer pipe 10. The gas chamber 28 is set so as to face the diameter portion 14 with a minute gap E (= L1-L2), and an annular gas chamber 28 having no unevenness on the inner surface is formed between the hollow outer tube 10 and the hollow inner tube 20. ( See FIG. 1B and FIG. 2A ).

  In the preferred embodiment, as shown in FIG. 2 (C), the inner diameter R2 of the hollow inner tube 20 is gradually increased from the one end 22 side to the other end 23 side, and the gas G sucked into the hollow inner tube 20 has an inner diameter R2. Grind by expanding R2. In a further preferred embodiment, as shown in FIG. 4 (E), the insertion end 22 of the hollow inner tube 20 is provided with an unevenness 22c along the inner circumferential direction, and an unevenness is formed on the outer peripheral edge of the minute gap E.

The method and apparatus for producing fine bubbles according to the present invention is such that the outlet side peripheral wall 15 having the predetermined inner diameter R1 of the hollow outer tube 10 having the reduced diameter portion 14 formed on the inner peripheral surface 15a of the predetermined depth portion L1 has the outlet side peripheral wall 15 thereof. the vent hole 16 aligned a central axis I in a tangential direction to the inner peripheral surface 15a without irregularities a curved surface of the outlet-side wall 15 with one puncture of the inner peripheral surface 15a, is smaller than the outer diameter R3 and contracted the predetermined inner diameter R1 The end 22 of the hollow inner tube 20 having the same inner diameter R2 as the portion 14 and the flange 24 having the outer diameter R0 larger than the predetermined inner diameter R1 formed on the outer peripheral surface 25b of the predetermined depth portion L2 is aligned with the outlet 13 of the hollow outer tube 10. hollow the insertion end 22 of the hollow inner tube 20 together to a pointing write Mutotomoni insertion end outer peripheral surface 25b curved without irregularities to the to fix the flange 24 of the hollow tube 20 around the outlet 13 of the hollow outer tube 10 Reduction of outer tube 10 The pressurized liquid Q is introduced from the inlet 12 while facing the portion 14 with the minute gap E (= L1-L2) and communicating the vent hole 16 of the hollow outer tube 10 with the gas phase Pa. The gas G is sucked from the gas phase Pa into the hollow inner tube 20 through the annular gas chamber 28 formed between the hollow outer tube 10 and the hollow inner tube 20 and having no unevenness on the inner surface and the minute gap E. Moreover, since the sucked gas G is discharged from the other end 23 of the hollow inner tube 20 while being crushed, the following advantageous effects are obtained.

(A) Insert the hollow inner pipe 20a having the outer diameter R3 smaller than the inner diameter R1 into the outlet 13 having the inner diameter R1 of the hollow outer pipe 10 having the reduced diameter portion 14 formed on the inner peripheral surface 15a. By forming the ventilation hole 16 in the peripheral wall 15, a cylindrical shape surrounded by the outer peripheral surface 25b of the hollow inner tube 20 and the inner peripheral surface 15a of the hollow outer tube 10 around the hollow inner tube 20 for introducing the pressurized liquid Q. An annular gas chamber 28 can be formed that extends to.
(B) Further, by making the insertion end 22 of the hollow inner pipe 20 face the reduced diameter portion 14 of the hollow outer pipe 10 with the minute gap E, the entire circumference of the cross section of the hollow inner pipe 20 (360 It is possible to form an annular slit that contacts the gas chamber 28 over a degree.

(C) By sucking the gas G in the gas chamber 28 into the pressurized liquid Q through the annular slit having the minute gap E over the entire circumference, compared with the conventional point-like minute intake hole 62e (see FIG. 6). The suction of the gas G is not likely to be stopped due to clogging, etc., and the fine bubbles S can be stably generated even after continuous use for a long period of time.
(D) By swirling the gas G in the annular gas chamber along the inner peripheral wall of the hollow outer tube 10, the variation of the gas G in the gas chamber 28 is avoided, and the pressurized liquid Q is supplied from the annular slit over the entire circumference. Mixing of the sucked gas (bubbles) G can be made uniform.

(E) Further, the inner peripheral surface 15a of the hollow outer tube 10 connected to the ventilation hole 16 is formed into a curved surface without unevenness, and the friction loss of the gas flow path along the inner peripheral surface 15a is suppressed so that the pressurized liquid Q is sucked. It can be expected to further homogenize the mixing of the gas G to be generated and eventually to homogenize the generated fine bubbles S.
(F) Furthermore, by forming the unevenness 22c along the inner circumferential direction on the insertion end 22 of the hollow inner tube 20 and forming the unevenness on the outer peripheral edge of the annular slit, the pressurized liquid is crushed while the gas G is crushed from the annular slit. It can be sucked to Q, and it can be expected that the diameter of the generated fine bubbles S can be reduced.

Hereinafter, modes and embodiments for carrying out the present invention will be described with reference to the accompanying drawings.
It is explanatory drawing of one Example of the fine bubble generator by this invention. It is explanatory drawing of the other Example of the fine bubble generator by this invention. It is explanatory drawing of the hollow outer tube which comprises the microbubble generator of this invention. It is explanatory drawing of the hollow inner pipe | tube which comprises the microbubble generator of this invention. It is explanatory drawing of the connection conduit which comprises the microbubble generator of this invention. It is explanatory drawing of an example of the conventional fine bubble generator.

  FIG. 1 shows an embodiment of a fine bubble generator 1 of the present invention for supplying fine bubbles S to a target water area such as a fish farm or a closed water area. The generator 1 shown in FIG. 1 (A) has a hollow outer tube 10a in which a vent hole 16 is formed in a peripheral wall 15 of a hollow portion 11 having a predetermined inner diameter R1, and an end 22 of the hollow outer tube 10a is aligned with an outlet 13 of the hollow outer tube 10a. It has a hollow inner tube 20a to be inserted therein and a connecting conduit 40a which is aligned with the inlet 12 of the hollow outer tube 10a and pressed against it. As shown in FIG. 1B, the hollow outer pipe 10a, the hollow inner pipe 20a, and the connecting conduit 40a are combined and integrated by the fixing means 30 to form an ejector. The material of each of the tubes 10a, 20a, 40a can be arbitrarily selected, but can be made of, for example, stainless steel or synthetic resin. However, the connecting conduit 40a is not essential to the present invention as will be described later, and can be omitted.

  In FIG. 1B, the vent hole 16 of the hollow outer tube 10a is connected to the gas phase Pa by connecting to the gas supply passage 66 (see FIG. 6), for example. Then, for example, the liquid channel 64 (see FIG. 6) is connected to the connecting conduit 40a, the pressurized liquid Q is introduced into the inlet 12 of the hollow outer tube 10a through the connecting conduit 40a, and the pressurized liquid Q is introduced from the vent hole 16. The gas G is sucked in (self-priming) and mixed. The pressurized liquid Q mixed with the gas G is introduced from the outlet 13 of the hollow outer pipe 10a to one end 22 of the hollow inner pipe 20a and is discharged from the other end 23 of the hollow inner pipe 20a. The mixed gas (bubbles) G is crushed by the cavitation generated by the expansion of the pipeline, and the fine bubbles S are generated.

  In the illustrated hollow outer tube 10a, an inlet 12 and an outlet 13 have a hollow portion 11 having a predetermined inner diameter R1, and a reduced diameter portion 14 is formed from the outlet 13 of the hollow portion 11 to an inner peripheral surface 15a of a predetermined depth portion L1. The vent hole 16 is formed in the peripheral wall 15 on the outlet side of the reduced diameter portion 14. When the pressurized liquid Q introduced from the inlet 12 passes through the reduced diameter portion 14 by providing the reduced diameter portion (small diameter pipe line) 14 with the small inner diameter R2 between the inlet 12 and the outlet 13 of the predetermined inner diameter R1. A negative pressure is generated in the air, and the gas G can be sucked from the ventilation hole 16.

  In the illustrated example, the inlet 12 and the outlet 13 of the hollow outer tube 10a have the same inner diameter R1, but if the reduced diameter portion 14 can be formed at the predetermined depth portion L1, the inner diameters of the inlet 12 and the outlet 13 have different sizes. May be The amount of intake air from the ventilation hole 16 can be adjusted by providing a valve in the gas supply passage 66 connected to the ventilation hole 16, for example. Therefore, the diameter of the ventilation hole 16 can be set arbitrarily, and it is also effective to make the ventilation hole 16 a relatively large diameter in order to prevent clogging (see FIG. 3A).

  FIG. 3 (A) shows another embodiment of the hollow outer tube 10a, and a side view of the inlet side thereof is shown in FIG. 3 (B). The flange 44 of the connecting conduit 40a, which will be described later, is pressed against the peripheral end surface of the inlet 12 of the hollow outer tube 10a and fixed, but as shown in FIG. 3B, for fixing the connecting conduit 40a to the inlet peripheral surface 12a. The fixing means 30 (bolt hole or the like) can be provided. Further, the inlet 12 of the hollow outer tube 10a is provided with a fitting portion (diameter expansion portion) 12b to which a fitting projection 43b (see FIG. 5A) provided on the pressing surface of the flange 44 of the connecting conduit 40a is fitted. be able to.

  3D is a side view of the hollow outer tube 10a shown in FIG. 3A on the outlet side. A flange 24 of a hollow inner tube 20a, which will be described later, is pressed against the peripheral end surface of the outlet 13 of the hollow outer tube 10a and fixed, but as shown in FIG. 3D, the hollow inner tube 20a is fixed to the outlet peripheral surface 13a. A fixing means 30 (bolt hole or the like) for fixing can be provided. Further, at the outlet 13 of the hollow outer tube 10a, there is provided a fitting portion (expanded portion) 13b for fitting a fitting projection 22b (see FIG. 4 (A)) provided on the pressing surface of the flange 24 of the hollow inner tube 20a. Can be provided.

  Returning to the embodiment of FIG. 1, the hollow inner tube 20a of the illustrated example has a hollow portion 21 having an outer diameter R3 smaller than a predetermined inner diameter R1 of the outlet 13 of the hollow outer tube 10a. The inner diameter R2 is the same as the above, and a flange 24 having an outer diameter R0 larger than the predetermined inner diameter R1 is formed on the outer peripheral surface 25b of the predetermined depth portion L2 from one end (insertion end) 22 of the hollow portion 21. In the illustrated example, the flange 24 of the hollow inner pipe 20a has the same outer diameter R0 as the outlet of the hollow outer pipe 10a, but the flange 24 need only be larger than the outlet inner diameter R1 of the hollow outer pipe 10a, and not necessarily the outlet outer diameter R0. Need not be the same size as. Further, in the illustrated example, the flange 24 is located at a depth L3 from the other end 23 of the hollow inner pipe 20a, but the distance between the flange 24 and the other end 23 is not limited to the illustrated example, and for example, the flange 24 and the other end 23 may be used. The flange 24 may be formed on the outer peripheral surface of the other end 23 of the hollow inner tube 20a by setting the distance L3 to zero.

  As shown by the arrow B in FIG. 1 (A), one end 22 of the hollow inner pipe 20a is inserted into the outlet 13 of the hollow outer pipe 10a while being aligned, and the flange 24 of the hollow inner pipe 20a is surrounded by the outlet of the hollow inner pipe 20a. The insertion end 22 of the hollow inner tube 20a is pressed against the surface 13a to face the reduced diameter portion 14 of the hollow outer tube 10a. As shown in FIG. 1B, a portion (a portion having a predetermined depth from one end 22) L2 forming the flange 24 of the hollow inner tube 20a is such that the insertion end 22 of the hollow inner tube 20a has a reduced diameter of the hollow outer tube 10a. It is set so as to face the portion 14 with a minute gap E (= L1-L2), that is, to be slightly smaller than the predetermined depth L1 of the reduced diameter portion 14 of the hollow outer tube 10a. For example, the insertion end 22 of the hollow inner tube 20a and the reduced diameter portion 14 of the hollow outer tube 10a are set to face each other with a minute gap E of about 0.1 mm to 10 mm, preferably about 0.5 mm to 6 mm. ..

  After inserting the hollow inner tube 20a into the outlet 13 of the hollow outer tube 10a, the flange 24 of the hollow inner tube 20a is fixed to the outlet peripheral surface 13a of the hollow outer tube 10a. For example, the fixing means 30 such as an adhesive or welding may be used to firmly fix, but preferably the fixing means 30 such as a bolt is used to fix the hollow inner tube 20a and the hollow outer tube 10a in a separable manner. To do. By using the fixing means 30 such as a bolt, the hollow inner tube 20a and the hollow outer tube 10a can be separated from each other for maintenance and repair, if necessary. Further, if necessary, the tightening strength of bolts or the like may be adjusted or a gasket or the like may be sandwiched to adjust the minute gap E between the insertion end 22 of the hollow inner tube 20a and the reduced diameter portion 14 of the hollow outer tube 10a. It is possible.

  As shown in FIG. 1 (B), since the outer diameter R3 of the hollow inner tube 20a is smaller than the outlet inner diameter R1 of the hollow outer tube 10a, the outer peripheral surface 25b of the hollow inner tube 20a fitted to the hollow outer tube 10a. An annular gas chamber 28 extending in a cylindrical shape can be formed between and the inner peripheral surface 15a of the hollow outer tube 10a (see also FIG. 1D). Further, the outlet side peripheral wall 15 of the hollow outer tube 10a is provided with the vent hole 16, so that the gas G is taken into the annular gas chamber 28 from the gas phase Pa by communicating the vent hole 16 with the gas phase Pa. be able to.

  Further, the hollow portion 21 of the hollow inner pipe 20a has the same inner diameter R2 as the reduced diameter portion 14 of the hollow outer pipe 10a, and the insertion end 22 of the hollow inner pipe 20a and the reduced diameter portion 14 of the hollow outer pipe 10a and the minute gap E. By facing each other, it is possible to form an annular slit having a minute gap E in contact with the gas chamber 28 over the entire circumference of 360 degrees in the small-diameter conduit connecting the reduced diameter portion 14 and the hollow portion 21 of the hollow inner tube 20a. (See also Figure 1C). That is, as will be described later, when the pressurized liquid Q is introduced into the small-diameter conduit that connects the reduced-diameter portion 14 of the hollow outer pipe 10a and the hollow portion 21 of the hollow inner pipe 20a, a small amount is generated from the entire circumference of the small-diameter pipe passage. The gas G in the gas chamber 28 can be sucked (self-sucking) through the annular slit of the gap E.

  FIG. 4 (A) shows another embodiment of the hollow inner tube 20a, and a side view of the insertion end side is shown in FIG. 4 (B). As shown in the figure, the flange 24 of the hollow inner tube 20a can be provided with a fixing means 30 (bolt hole or the like) for fixing to the outlet peripheral surface 13a of the hollow outer tube 10a. Further, the pressing surface of the flange 24 of the hollow inner tube 20a can be provided with a fitting projection 22b which is fitted to the fitting portion (diameter expansion portion) 13b of the outlet 13 of the hollow outer tube 10a.

  Returning to the embodiment of FIG. 1 again, the connecting conduit 40a of the illustrated example has a hollow portion 41 having the same predetermined inner diameter R1 as the inlet 12 of the hollow outer tube 10a, and an outer peripheral surface of one end 43 of which is larger than the predetermined inner diameter R1. A flange 44 having a diameter R0 is formed. In the illustrated example, the flange 44 of the connecting conduit 40a has the same outer diameter R0 as the outlet of the hollow outer tube 10a, but the flange 44 may be larger than the inner diameter R1 of the inlet of the hollow outer tube 10a.

  As shown by the arrow B in FIG. 1 (A), the flange 44 at the one end 43 of the connecting conduit 40a is pressed against the inlet 12 of the hollow outer tube 10a while being aligned, and fixed to the inlet peripheral surface 12a. For example, the fixing means 30 such as an adhesive or welding can be used to firmly fix it, but like the hollow inner tube 20a, the connecting conduit 40a can also be separated using the fixing means 30 such as a bolt. It is desirable to fix it to the hollow outer tube 10a. By using the fixing means 30 such as a bolt, the connecting conduit 40a and the hollow outer tube 10a can be separated from each other as required to perform maintenance and repair.

  FIG. 5A shows another embodiment of the connection conduit 40a, and a side view of the pressing end side is shown in FIG. 5B. As shown in the figure, the flange 44 of the connecting conduit 40a can be provided with fixing means 30 (bolt holes or the like) for fixing to the inlet peripheral surface 12a of the hollow outer tube 10a. Further, the pressing surface of the flange 44 of the connecting conduit 40a may be provided with a fitting projection 43b which is fitted to the fitting portion (diameter expansion portion) 12b of the inlet 12 of the hollow outer tube 10a.

  In the present invention, the connection conduit 40a has a function of connecting the liquid flow path 64 (see FIG. 6) to the inlet 12 of the hollow outer tube 10a. That is, one end 43 of the connection conduit 40a is fixed to the inlet 12 of the hollow outer tube 10a, and the other end 42 is connected to the liquid flow path 64. As shown in the connecting conduit 40b of FIG. 5C, a mounting portion (for example, a screwing portion) 45 of the liquid flow path 64 can be provided on the outer peripheral surface of the connecting conduit 40a as required. The pressurized liquid Q introduced from the liquid flow path 64 to the inlet 12 of the hollow outer pipe 10a via the connection conduit 40a has a small diameter in which the reduced diameter portion 14 of the hollow outer pipe 10a and the hollow portion 21 of the hollow inner pipe 20a are continuous. A negative pressure is generated when the gas G passes through the pipeline, and as shown in FIG. 1C, the gas G in the gas chamber 28 is sucked (automatically) from the annular slit of the minute gap E formed over the entire circumference of the small diameter pipeline. It is sucked) and mixed.

  However, the connection conduit 40a is not essential to the present invention, and the connection conduit 40a can be omitted if the liquid flow path 64 can be directly connected to the inlet 12 of the hollow outer tube 10a. That is, an ejector is composed only of the hollow outer pipe 10a and the hollow inner pipe 20a, and the liquid flow path 64 (see FIG. 6) is directly connected to the inlet 12 of the hollow outer pipe 10a. It is also effective to provide a mounting portion (for example, a screwing portion) of the liquid flow path 64 on the outer peripheral surface of the inlet 12 of the hollow outer tube 10a. Also in this case, the gas G in the gas chamber 28 is sucked from the annular slit of the minute gap E when passing through the small-diameter conduit connecting the reduced diameter portion 14 of the hollow outer pipe 10a and the hollow portion 21 of the hollow inner pipe 20 ( It is self-primed and mixed with the pressurized liquid Q.

  Since the fine bubble generator 1 of the present invention forms the annular slit of the minute gap E over the entire circumference in the small diameter conduit of the pressurized liquid Q, and sucks the gas G into the pressurized liquid Q through the annular slit, Compared to the conventional point-by-point suction of the gas G by the fine intake holes 62e described with reference to FIG. 6, it is possible to eliminate the possibility of stopping the suction of the gas G due to clogging or the like. Even if a part of the slit is closed due to metal corrosion or the like, the annular slit is formed over the entire circumference, so that the entire slit can be prevented from being closed and the suction of the gas G can be continued. Further, by sucking the gas G from the annular slit over the entire circumference, the suction force of the gas G is increased as compared with the conventional point-wise suction, and the amount of the gas G mixed with the pressurized liquid Q, and thus the hollow outer tube. It is possible to increase the amount of the fine bubbles S discharged from the outlet 13 of 10a through the hollow inner tube 20a.

  Further, the fine bubble generator 1 of the present invention can also adjust the particle size of the fine bubbles S to be discharged by adjusting the size of the minute gap E of the annular slit. That is, by making the minute gap E small or large, it is possible to make the particle size of the gas (bubble) G sucked and mixed by the pressurized liquid Q from the minute gap E small or large. In the present invention, the gas G mixed with the pressurized liquid Q is crushed into fine bubbles S when the pressurized liquid Q is discharged, but the particle size of the gas G should be made small or large at the stage of mixing with the pressurized water Q. Thereby, the particle size of the discharged fine bubbles S can be adjusted.

  Thus, it is possible to achieve the object of the present invention to provide an "ejector-type fine bubble generating method and device capable of continuously supplying fine bubbles for a long period of time".

  Since the annular slit having the minute gap E over the entire circumference makes the entire periphery of the small-diameter pipe contact the gas G, the mixing of the pressurized liquid Q and the gas G becomes non-uniform in each portion in contact with the gas G. Can also be considered. The non-uniformity of the mixing in each part may cause the non-uniformity of the particle size of the generated fine bubbles S. In the fine bubble generator 1 of the present invention, the annular gas chamber 28 extending in a cylindrical shape is formed around the small diameter conduit, and the gas chamber 28 and the pressurized liquid Q are brought into contact with each other through the annular slit. By avoiding the variation of the gas G in the gas chamber 28, it is possible to prevent the mixture of the pressurized liquid G and the gas G from becoming non-uniform in each part.

  Specifically, as shown in FIG. 1D, it is desirable to swirl the gas G in the annular gas chamber 28 along the inner peripheral wall of the hollow outer tube 10a. This figure shows a cross-sectional view of the ejector shown in FIG. 1 (B) taken along the line DD, showing the inner peripheral surface 15a of the hollow outer tube 10a with the central axis I of the vent hole 16 of the hollow outer tube 10a offset from the center. It indicates that they are aligned along the tangential direction. With such arrangement of the vent holes 16, the gas G can be sucked from the gas phase Pa along the tangential direction of the inner peripheral surface 15a, and the sucked gas G can be swirled along the inner peripheral wall of the hollow outer tube 10a. .. By swirling the gas G in the gas chamber 28, it can be expected that variations in the mixing of the pressurized liquid G and the gas G over the entire circumference will be eliminated, and that the particle size of the generated fine bubbles S will be uniform.

  FIG. 2 (A) shows another embodiment of the micro-bubble generating device 1 of the present invention in which the inner peripheral surface 15a of the outlet side peripheral wall 15 connected to the ventilation hole 16 of the hollow outer tube 10a has a curved surface without irregularities. As described above, the micro-bubble generating device 1 of the present invention forms the annular gas chamber 28 that extends in a cylindrical shape around the small-diameter conduit, and forms the gas chamber 2 through the annular slit of the minute gap E over the entire circumference. Since the gas G and the pressurized liquid Q are brought into contact with each other, the mixture of the pressurized liquid Q and the gas G may be non-uniform for each part. Whilst the gas G in the gas chamber 28 is swirled, the variation in mixing can be suppressed to a certain extent, but in order to generate the fine bubbles S having a uniform particle size, it is desirable to make the variation in mixing as small as possible.

  The fine bubble generator 1 shown in FIG. 2 (A) uses a hollow outer tube 10b in which the inner peripheral surface 15a of the outlet side peripheral wall 15 is a curved surface without unevenness, and friction loss of the gas flow path along the inner peripheral surface 15a. Is small. Another example of the hollow outer tube 10b in which the inner peripheral surface 15a is a curved surface without unevenness is shown in FIG. 3 (C). The hollow outer tube 10b of the illustrated example has the same side view as the hollow outer tube 10a described above in the inlet side and the outlet side shown in FIGS. 3B and 3D, but the gas G in the gas chamber 28 flows. By forming the inner peripheral surface 15a of the hollow outer tube 10a into a curved surface without irregularities, turbulent flow in the gas chamber 28 is prevented from occurring and a smooth flow is secured.

  Preferably, as shown in FIG. 2 (A), the outer peripheral surface 25b on the insertion end 22 side is combined with the hollow inner tube 20b having a curved surface without unevenness. Another example of the hollow outer tube 10b in which the outer peripheral surface 25b has a curved surface without unevenness is shown in FIG. 4 (C). That is, the inner peripheral surface 15a of the hollow outer tube 10b is formed into a curved surface without unevenness, and the outer peripheral surface 25b of the hollow inner tube 20a which is inserted into the outlet 13 of the hollow outer tube 10a by centering is formed into a curved surface with no unevenness. The entire inner surface of the gas chamber 28 around the pipe is made into a curved surface without unevenness to prevent the turbulent flow of the gas G from occurring. As shown in FIG. 2 (B), by making the entire inner surface of the gas chamber 28 into a curved structure, the gas G in the gas chamber 2 can be smoothly flowed through the annular slit of the minute gap E, and the pressure is increased. It can be expected that the variation in the mixing of the liquid Q and the gas G can be suppressed to be small.

  FIG. 2C shows another embodiment of the fine bubble generator 1 of the present invention in which the inner diameter R2 of the hollow inner tube 20 is gradually increased from the one end 22 side to the other end 23 side. As described above, in the fine bubble generator 1 of the present invention, the gas (bubbles) G is crushed by the cavitation caused by the expansion of the conduit at the time of discharging the pressurized liquid Q to generate the fine bubbles S, but before the discharge. By gradually increasing the inner diameter R2 of the hollow inner tube 20, the hollow inner tube 20 functions similarly to the ejector (venturi) 62 described above with reference to FIG. The gas (bubbles) G can be collapsed by the change, and the diameter of the discharged fine bubbles S can be reduced.

  The fine bubble generator 1 shown in FIG. 2 (C) uses a hollow inner tube 20c in which the distance between the flange 24 and the other end 23 is lengthened and the inner diameter R2 is gradually enlarged toward the other end 23 side. .. Another example of the hollow inner tube 20c in which the inner diameter R2 is gradually enlarged is shown in FIG. The hollow inner pipe 20c of the illustrated example has the same side view as the hollow inner pipes 20a, 20c described above in the insertion end side shown in FIG. 4B, but has an inner diameter R2 from the one end 22 side to the other end 23 side. The distance L4 between the flange 24 and the other end 23 is lengthened so that the distance gradually increases.

  Preferably, as shown in FIG. 4 (E), an annular slit having a minute gap E is provided at the insertion end 22 of the hollow inner tube 20 so as to form an unevenness 22c along the inner circumferential direction and to mix the pressurized liquid Q and the gas G. Unevenness is formed on the outer peripheral edge of the. The gas G sucked into the pressurized liquid Q through the annular slit is mixed as a bubble decomposed by the spiral shear flow formed on the outer periphery of the annular slit, but the outer peripheral edge of the annular slit is long and By using a complicated shape, it is expected that the bubbles to be mixed will be decomposed and the particle size will be reduced. As shown in FIG. 4D, by gradually enlarging the inner diameter R2 of the hollow inner tube 20b toward the other end 23 side, the fine bubbles S in the pressurized water Q before being discharged can be finely divided, but it is mixed with the pressurized water Q. By reducing the particle size of the gas (bubbles) G, it is expected that the diameter of the discharged fine bubbles S can be further reduced.

DESCRIPTION OF SYMBOLS 1 ... Micro bubble generator 10 (10a, 10b) ... Hollow outer tube 11 ... Hollow part 12 ... Hollow part inlet 12a ... Inlet peripheral surface (outer tube end surface) 12b ... Fitting part 13 ... Hollow part outlet 13a ... Outlet peripheral surface (Outer tube end face)
13b ... Fitting part 14 ... Reduced diameter part 15 ... Peripheral wall 15a ... Inner peripheral surface 15b ... Outer peripheral surface 16 ... Vent hole 20 (20a, 20b, 20c) ... Hollow inner tube 21 ... Hollow part 22 ... Inserting end (one end)
22a ... One end opening 22b ... Fitting protrusion 22c ... Unevenness 23 ... Other end 23a ... Other end opening 24 ... Flange 25 ... Peripheral wall 25a ... Inner peripheral surface 25b ... Outer peripheral surface 28 ... Gas chamber 30 ... Fixing member 40 (40a, 40b) ... Connection conduit 41 ... Hollow part 42 ... Pushing end (one end)
42a ... One end opening 43 ... Other end 43a ... Other end opening 43b ... Fitting protrusion 44 ... Flange 45 ... Attachment part 60 ... Ejector type micro bubble generator
61 ... Liquid storage tank 62 ... Ejector 62a ... Hollow part 62b ... Pipe line inlet 62c ... Pipe line outlet 62d ... Reduced diameter part 62e ... Fine suction hole 63 ... Pump 64 ... Liquid flow passage 65 ... Flow control valve 66 ... Gas supply passage 67 ... Opening / closing cock E ... Small gap (between hollow outer tubes) G ... Gas I ... Central axis L1 (of vent holes) ... Predetermined depth portion L2 (of hollow outer tube) ... (in hollow) Predetermined depth of the pipe Pa ... Gas phase Pb ... Liquid phase Q ... Liquid R0 ... Outer diameter (inlet) outer diameter of hollow outer tube (flange outer diameter of hollow inner tube)
R1 ... Hollow outer tube outlet (inlet) inner diameter R2 ... Hollow outer tube reduced diameter inner diameter R3 ... Hollow inner tube (insertion side) outer diameter R4 ... Hollow inner tube (discharge side) outer diameter R5 ... Hollow inner tube (Discharge side) inner diameter R7 ... Connection conduit (introduction side) outer diameter S ... Fine bubbles

Claims (6)

Vents with a central axis aligned in the tangential direction of the inner peripheral surface of the outlet side peripheral wall of the hollow outer tube in which the inlet and outlet have a predetermined inner diameter and a reduced diameter portion is formed on the inner peripheral surface of a predetermined depth portion. greater than the predetermined inner diameter to the outer peripheral surface of a predetermined depth portion in the same inner diameter as the inner peripheral surface of the outlet side wall and without a patterned surface with one puncture, predetermined outer diameter smaller than the inner diameter and the reduced diameter portion of said hollow outer tube one end of the outer diameter flange formed hollow tubes and the hollow outer tube curved without irregularities to the outer peripheral surface of the write Mutotomoni insertion end pointing to fit the core to the outlet of the hollow in the outlet periphery of the hollow outer tube While fixing the flange of the tube, make the insertion end of the hollow inner tube face the reduced diameter part of the hollow outer tube with a small gap, and introduce the pressurized liquid from the inlet while communicating the ventilation hole of the hollow outer tube with the gas phase. the formed between through the vent hole from the gas phase of a hollow outer tube and hollow inner tube ring Fine bubble generating method in which a release while crushing a gas gas was aspirated and drawn into the hollow inner tube through without unevenness gas chamber and the minute gap to the inner surface of the other end of the hollow tube in. The method of claim 1 , wherein the inner diameter of the hollow inner tube is gradually expanded from one end side to the other end side, and the gas sucked into the hollow inner tube is pulverized by expanding the inner diameter. 3. The method for generating fine bubbles according to claim 1 , wherein unevenness is formed along the inner circumferential direction at the insertion end of the hollow inner tube, and unevenness is formed at the outer edge of the minute gap. The inlet and vent outlet is aligned center axis in the tangential direction of the inner peripheral surface of the outlet side peripheral wall and the outlet-side peripheral wall reduced diameter portion is formed on the inner peripheral surface of a predetermined depth portion at a predetermined inner diameter with one puncture A hollow outer tube whose inner peripheral surface of the outlet side peripheral wall is a curved surface without unevenness, an outer diameter smaller than a predetermined inner diameter of the hollow outer tube and an inner diameter equal to that of the reduced diameter portion and larger than a predetermined inner diameter on an outer peripheral surface of a predetermined depth portion. A hollow inner tube having a flange having an outer diameter and having one end aligned with the outlet of the hollow outer tube and having an outer peripheral surface of the insertion end having a curved surface without unevenness, and a hollow inner tube around the outlet of the hollow outer tube comprising a fixing member for fixing the flange, forming part of the flange of the hollow tube with end plug of the hollow tube is set so as to face in a reduced diameter portion and a small gap of the hollow outer tube, said hollow outer An annular surface between the pipe and the hollow inner pipe with no unevenness By forming a gas chamber fine bubble generator. The device according to claim 4 , wherein the inner diameter of the hollow inner tube is gradually increased from one end side to the other end side. The device according to claim 4 or 5 , wherein the hollow inner tube is provided with irregularities along the inner circumferential direction at the insertion end thereof.