Fine bubble generator

Abstract

To provide a fine bubble generator which can generate fine bubbles from also a gas introduced from the exterior in addition to a gas dissolved in a liquid.SOLUTION: A body 1 of this generator comprises a channel member 2 in which a flow channel 5 through which water flows is formed and which generates fine bubbles in passing water. The channel member 2 has: a reduction part 7 of which a cross sectional area reduces from an upstream side to a downstream side of the flow channel 5; an enlarged part 8 of which a cross sectional area increases from the upstream side to the downstream side; a narrow flow channel part 9 which is formed between the reduction part 7 and the enlarged part 8; and a plate member 10 which regulates water flow. The plate member 10 comprises a shell 11 in which an eccentric long hole 14 through which water passes is formed, and which is provided on an upstream side of the reduction part 7. The shell 11 introduces a gas such as air from the exterior of the body 1 into a space 16 formed between the reduction part 7 and the plate member 10.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a fine bubble generator capable of generating fine bubbles in a liquid.

Background Art

[0002] In this type of fine bubble generator, the applicant of the present application has proposed a device having a constriction portion (7) whose cross-sectional area decreases from the upstream side to the downstream side of the flow path (5), a dilation portion (8) whose cross-sectional area increases from the upstream side to the downstream side of the flow path (5), a thin flow path portion (9) formed between the constriction portion (7) and the dilation portion (8), and a plate member (25) in which an eccentric long hole (27) is formed (for example, Patent Document 1). When liquid flows into this fine bubble generator, when the liquid passes through the eccentric long hole (27) of the plate member (25), the flow of the liquid is made helical and the flow velocity of the liquid is increased. Then, the pressure around the liquid flowing from the thin flow path portion (9) into the dilation portion (8) is reduced to a negative pressure, so that the gas dissolved in this liquid becomes fine bubbles by cavitation, and fine bubbles are generated in the liquid.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, there has been an increasing demand from users to use a liquid containing more fine bubbles. However, since the fine bubble generator of Patent Document 1 generates fine bubbles from the gas dissolved in the flowing liquid, there is a problem that it cannot generate more fine bubbles than the amount of the gas.

[0005] Accordingly, an object of the present invention is to provide a fine bubble generator capable of generating fine bubbles not only from a gas dissolved in a liquid but also from a gas introduced from the outside. **Means for Solving the Problems**

[0006] The fine bubble generator of the present invention is provided with a flow path in which a liquid flows inside, and fine bubble generating means for generating fine bubbles in the passing liquid. The fine bubble generating means includes a constriction portion whose cross-sectional area decreases from the upstream side to the downstream side of the flow path, an enlargement portion whose cross-sectional area increases from the upstream side to the downstream side, a narrow flow path portion formed between the constriction portion and the enlargement portion, and a restricting plate for restricting the flow of the liquid. The restricting plate is provided with a passage hole through which the liquid passes, is disposed on the upstream side of the constriction portion, and includes gas introducing means. The gas introducing means introduces gas from the outside of the fine bubble generator into the space formed by the constriction portion and the restricting plate. **Advantages of the Invention**

[0007] According to the present invention, a liquid containing more fine bubbles can be supplied. **Brief Description of the Drawings**

[0008]

Figure 1

Figure 2

[0009] Hereinafter, preferred embodiments of the fine bubble generator according to the present invention will be described with reference to the accompanying drawings. In all these drawings, common parts will be denoted by common reference numerals.

[0010] Figures 1 and 2 show the configuration of a fine bubble generator according to an embodiment of the present invention. Based on these figures, 1 is the main body of the fine bubble generator. The main body 1 is generally composed of a flow path member 2, an upstream joint member 3, and a downstream joint member 4. Inside these flow path member 2, upstream joint member 3, and downstream joint member 4, a flow path 5 through which water as a liquid flows is formed. The outer shape of the main body 1 of this embodiment is formed in a substantially cylindrical shape. Therefore, the outer shapes of the flow path member 2, upstream joint member 3, and downstream joint member 4 are also formed in a substantially cylindrical shape, and they are arranged and connected coaxially in the order of the upstream joint member 3, flow path member 2, and downstream joint member 4 from the upstream of the flow path 5. However, the present invention is not limited to this.

[0011] In this embodiment, as shown in FIG. 1, the flow path member 2, upstream joint member 3, and downstream joint member 4 are formed as separate components. However, when the diameter of the hollow portion 21 in the attachment portion 23 (to be described later) of the upstream joint member 3 is larger than the diameter of the inlet of the reduced portion 7, which is the diameter of the inlet of the hollow portion 6 (to be described later) of the flow path member 2, the flow path member 2 and the upstream joint member 3 may be integrally formed. Similarly, when the diameter of the hollow portion 31 in the attachment portion 33 (to be described later) of the downstream joint member 4 is larger than the diameter of the outlet of the enlarged portion 8, which is the diameter of the outlet of the hollow portion 6 (to be described later) of the flow path member 2, the flow path member 2 and the downstream joint member 4 may be integrally formed.

[0012] In this embodiment, the flow path member 2, the upstream joint member 3, and the downstream joint member 4 are made of a metal or a resin material. Note that all of these flow path member 2, upstream joint member 3, and downstream joint member 4 may be made of the same material or different materials. Here, regarding the joining method in the case where the flow path member 2, the upstream joint member 3, and the downstream joint member 4 are formed as separate parts like the main body 1 in FIG. 1, a method of joining is adopted so that water does not leak from the flow path 5 at the joining location. For example, if these members are made of a metal-based material, these members may be joined by welding or diffusion bonding. Also, for example, if these members are made of a resin-based material, they may be joined by any one of vibration welding, ultrasonic welding, bonding using an adhesive, or a combination thereof.

[0013] The flow path member 2 has a hollow portion 6 that forms a part of the flow path 5 inside. In this hollow portion 6, a liquid such as water is caused to flow, and fine bubbles such as microbubbles and ultrafine bubbles are generated from the gas dissolved in the liquid. Therefore, the flow path member 2 has a function as a fine bubble generation means for generating fine bubbles in a liquid such as water passing through. In this specification, in accordance with the classification by the diameter of general bubbles, fine bubbles with a diameter of 1 μm to 100 μm are referred to as microbubbles, and fine bubbles with a diameter of several tens of nm to less than 1 μm are referred to as ultrafine bubbles.

[0014] The hollow portion 6 is generally composed of a constriction portion 7, a dilation portion 8, and a narrow flow path portion 9. The flow path member 2 includes, in addition to the hollow portion 6, a plate member 10 as a regulating plate and a tube body 11. The constriction portion 7 smoothly guides the liquid flowing in from an eccentric long hole 14 (described later) of the plate member 10 to the narrow flow path portion 9. The constriction portion 7 is preferably formed such that the cross-sectional area gradually decreases from the upstream side to the downstream side of the flow path 5 in order to smoothly guide the liquid to the narrow flow path portion 9. Also, it is preferable that the liquid flowing in from the eccentric long hole 14 is guided to the narrow flow path portion 9 while flowing smoothly in a spiral shape. Therefore, in this embodiment, the constriction portion 7 is formed in a substantially inverted conical shape, but the present invention is not limited thereto.

[0015] The enlarging portion 8 generates fine bubbles from the gas dissolved in the liquid. When the liquid flowing into the enlarging portion 8 from the narrow flow path portion 9 flows toward the downstream side of the flow path 5, the pressure around this liquid is reduced to a negative pressure, so that the gas dissolved in this liquid becomes fine bubbles by cavitation, and fine bubbles are generated in the liquid. In order to facilitate this phenomenon, the enlarging portion 8 is preferably formed such that the cross-sectional area gradually increases from the upstream side to the downstream side of the flow path 5. In this embodiment, the enlarging portion 8 is formed in a substantially conical shape, but the present invention is not limited to this, and it is sufficient that the cross-sectional area increases from the upstream side to the downstream side of the flow path 5. Further, the shape of the enlarging portion 8 and the degree of increase in the cross-sectional area of the flow path 5 may be adjusted according to the amount of bubble generation and the bubble diameter at the time of generating the fine bubbles.

[0016] The narrow flow path portion 9 is formed between the reducing portion 7 and the enlarging portion 8 and fluidly connects these reducing portion 7 and enlarging portion 8. In this embodiment, the narrow flow path portion 9 is formed in a columnar shape, but the present invention is not limited to this. The flow velocity of the liquid in the narrow flow path portion 9 is determined by the pressure of the flow path 5 upstream of the narrow flow path portion 9. When the pressure of the upstream flow path 5 is the same, the flow velocity of the liquid in the narrow flow path portion 9 is determined by the diameter of the narrow flow path portion 9. Since the amount of bubble generation and the bubble diameter at the time of generating fine bubbles are also related to the flow velocity of the liquid discharged from the narrow flow path portion 9, the diameter of the narrow flow path portion 9 may be adjusted and changed according to the amount of bubble generation and the bubble diameter at the time of generating fine bubbles.

[0017] The plate member 10 is formed in a substantially disc shape and made of a metal or resin material. Note that the plate member 10 may be made of the same material as the flow path member 2, the upstream joint member 3, or the downstream joint member 4, or may be made of a different material. As shown in FIG. 1, in the present embodiment, the outer diameter of the plate member 10 is formed smaller than the outer diameter on the upstream side of the flow path member 2, a space for accommodating the plate member 10 is provided at the upstream end of the flow path member 2, the plate member 10 is joined to this space, and then the flow path member 2 and the upstream joint member 3 are joined. However, it may be configured to provide a space for accommodating the plate member 10 at the downstream end of the upstream joint member 3. Further, the outer diameter of the plate member 10 may be formed substantially the same as the outer diameter of the flow path member 2 or the outer diameter of the upstream joint member 3, and the plate member 10 may be joined to the upstream end of the flow path member 2 and the downstream end of the upstream joint member 3 so as to be sandwiched and attached between the flow path member 2 and the upstream joint member 3.

[0018] FIG. 2 shows a side view, a top view, and a cross-sectional view of the plate member 10. The plate member 10 functioning as a regulating plate for regulating the flow of liquid has a plurality of eccentric long holes 14 provided along the outer periphery in the vicinity of the outer periphery of the substantially disc-shaped plate member body 13, and a through hole 15 for penetrating and connecting the pipe body 11 is formed at the center of the plate member body 13, which is at a position substantially equidistant from these eccentric long holes 14. Therefore, the inlet 11A of the pipe body 11 described later is configured to be disposed on the central axis of the plate member 10, which is at a position substantially equidistant from the eccentric long holes 14. These eccentric long holes 14 are through holes provided through the plate member body 13, and the positions of the openings of the eccentric long holes 14 are offset in the substantially circumferential direction of the plate member body 13 on the upstream side surface 13A and the downstream side surface 13B of the plate member body 13. Therefore, by swirling the flow of the liquid passing through the eccentric long holes 14 to form a swirling flow and increasing the flow velocity, the negative pressure region generated when the liquid flowing from the narrow channel portion 9 into the enlarged portion 8 flows toward the downstream side of the flow path 5 can be increased. As a result, the bubble diameter of the fine bubbles generated in the liquid can be made finer, and the amount of bubbles generated during the generation of fine bubbles can be increased. It is preferable that the amount of displacement of the opening positions of the eccentric long holes 14 is substantially the same for each of the eccentric long holes 14. Therefore, it is preferable that the shapes of the eccentric long holes 14 are substantially the same for each of the eccentric long holes 14. Further, as shown in FIG. 1, it is preferable that the eccentric long holes 14 are provided such that the opening positions of the eccentric long holes 14 on the downstream side surface 13B are near the outer diameter on the upstream side of the constriction portion 7. In the present embodiment, four eccentric long holes 14 having a long hole shape are provided, but the shape and number of the eccentric long holes 14 may be adjusted according to the amount of bubbles generated and the bubble diameter during the generation of fine bubbles and may be changed.

[0019] Returning to FIG. 1 for explanation, the pipe body 11 introduces gas from the outside of the main body 1 into the space 16 formed by the constriction portion 7 and the plate member 10 in the flow path 5 and acts as a gas introduction means. The pipe body 11 of the present embodiment is, for example, a pipe made of metal such as SUS and bent in a substantially L shape, and is mainly composed of a gas discharge portion 11B and a gas introduction portion 11C.

[0020] The gas discharge part 11B is provided with an inlet 11A which is an outlet through which gas is discharged. The inlet 11A extends parallel to a joint body 22 (to be described later) of the upstream side joint member 3, that is, extends parallel to the flow path 5, so as to facilitate introduction of gas into the space 16. Further, the gas introduction part 11C is formed to extend in the outer peripheral direction of the joint body 22 from an end on the side opposite to the inlet 11A of the gas discharge part 11B, and is arranged to extend to the outside of the main body 1 through the joint body 22, and an intake port 11D which is an inlet through which gas flows in is provided at the tip. Note that it is preferable that the length of the pipe body 11 is shorter, because the distance through which the gas passes in the pipe body 11 becomes shorter and it becomes easier for the gas to flow into the pipe body 11. Therefore, it is also preferable that the lengths of the gas discharge part 11B and the gas introduction part 11C are shorter.

[0021] In the pipe body 11 of the present embodiment, the gas discharge part 11B is attached to the plate member 10 by passing through the through hole 15 of the plate member 10 and communicates with the space 16, and the gas introduction part 11C is attached to the joint body 22 by passing through the joint body 22 and communicates with the outside of the main body 1. Thus, the space 16 and the outside of the main body 1 communicate with each other through the pipe body 11. Here, since the amount of bubbles generated during generation of fine bubbles is also related to the amount of gas introduced from the inlet 11A, the length and diameter of the pipe body 11 may be adjusted according to the amount of bubbles generated during generation of fine bubbles and may be changed. Further, a gas source such as carbon dioxide gas may be connected to the intake port 11D of the gas introduction part 11C so that gas such as carbon dioxide gas can be introduced from this gas source into the space 16 through the pipe body 11.

[0022] When the liquid is flowing in the flow path 5, the pressure in the space 16 is lowest at the place immediately after the liquid flows in from the eccentric long hole 14. Therefore, in the space 16, the pressure is lowest on the downstream side surface 13B of the plate member main body 13, and the pressure increases as it goes in the direction of the narrow flow path part 9. Therefore, it is advantageous that the protruding length of the pipe body 11 into the space 16, that is, the length L from the downstream side surface 13B to the inlet 11A of the gas discharge part 11B, is a smaller value, because more gas can be introduced from the outside of the main body 1 due to the lower pressure in the space 16. It is preferable that the inlet 11A is provided flush with the downstream side surface 13B of the plate member 10.

[0023] The upstream joint member 3 has a hollow portion 21 inside which forms part of the flow path 5, and guides the liquid flowing into the hollow portion 21 from an elastic tube (not shown) connected to the upstream joint member 3 to the plate member 10 and the hollow portion 6 of the flow path member 2. The upstream joint member 3 has a joint body 22 and a mounting portion 23. In the main body 1 of FIG. 1, the upstream joint member 3 is connected to the flow path member 2 by joining the downstream edge of the joint body 22 to the upstream edge of the flow path member 2. The joint body 22 and the mounting portion 23 of the present embodiment are both formed in a cylindrical shape, and the mounting portion 23 is coaxially provided on the joint body 22 so that the mounting portion 23 protrudes from the joint body 22. Therefore, the upstream joint member 3 is formed in a tubular shape.

[0024] The mounting portion 23 enables an elastic tube such as a hose to be attached to the main body 1. By inserting and holding the end of the elastic tube at this mounting portion 23, the elastic tube is attached to the upstream joint member 3. A flange portion 24 for preventing the elastic tube from coming off is provided on the outer peripheral surface of the mounting portion 23. In the present embodiment, the flange portion 24 is provided on the outer peripheral surface of the upstream edge of the mounting portion 23, and has an annular convex portion 24a with a substantially constant outer diameter and a mountain-shaped convex portion 24b provided following the annular convex portion 24a and having an outer diameter that expands in the direction of the joint body 22 like a hose nipple. The upstream corner of the annular convex portion 24a on the insertion side of the elastic tube is R-processed to facilitate the insertion of the elastic tube, while the downstream corner of the annular convex portion 24a is processed to be 90° or less to make it difficult for the inserted elastic tube to come off. Also, since the mountain-shaped convex portion 24b is formed like a hose nipple, it facilitates the insertion of the elastic tube while making it difficult for the inserted elastic tube to come off. Therefore, the annular convex portion 24a and the mountain-shaped convex portion 24b, which are the flange portion 24, have a function as a retaining portion for preventing the elastic tube from coming off the mounting portion 23. In the present embodiment, a plurality of annular convex portions 24a and mountain-shaped convex portions 24b are provided on the outer peripheral surface of the mounting portion 23, and these annular convex portions 24a and mountain-shaped convex portions 24b are provided continuously in the axial direction of the mounting portion 23. However, the axial length, outer diameter of the mounting portion 23, the number, shape, and position of the flange portion 24 can be adjusted according to the type and inner diameter of the elastic tube used, the pressure of the liquid flowing into the flow path 5, etc., and can be changed.

[0025] The joint body 22 guides the liquid flowing in from the mounting portion 23 in the hollow portion 21 to the plate member 10 of the flow path member 2 and the hollow portion 6. In the present embodiment, the hollow portion 21 in the mounting portion 23 is formed in a cylindrical shape, and the diameter of the outlet of the hollow portion 21 in the joint body 22 is formed slightly larger than the diameter of the inlet of the hollow portion 6. However, the present invention is not limited to this, and it is only necessary to smoothly guide the liquid flowing in from the mounting portion 23 to the hollow portion 6. Further, a through hole 26 for penetrating and connecting the gas introduction portion 11C of the pipe body 11 is formed in the side wall of the joint body 22. The angle of the through hole 26 with respect to the flow path 5 corresponds to the angle between the gas discharge portion 11B and the gas introduction portion 11C in the pipe body 11, and in the present embodiment, it is provided at approximately 90 degrees, but this is an example.

[0026] Here, as in the main body 1 of FIG. 1, when the outer diameter of the mounting portion 23 is smaller than the outer diameter of the joint body 22, a transition portion 25 that transitions from the downstream edge portion of the mounting portion 23 to the upstream edge portion of the joint body 22 is formed. Here, usually, since the outer diameter of the mounting portion 23 is made to match the inner diameter of the elastic tube to be used, when the end portion of the elastic tube is inserted until it abuts against the transition portion 25, it cannot be inserted deeper than this transition portion 25. Therefore, at this time, the transition portion 25 has a function as a positioning portion indicating the insertion position of the end portion of the elastic tube.

[0027] The downstream joint member 4 has a hollow portion 31 that forms a part of the flow path 5 inside, and guides the liquid that has flowed in from the enlarged portion 8 of the flow path member 2 to an elastic tube (not shown) connected to the downstream joint member 4. The downstream joint member 4 has a joint body 32 and a mounting portion 33, similar to the upstream joint member 3. In the main body 1 of FIG. 1, the downstream joint member 4 is connected to the flow path member 2 by joining the upstream edge portion of the joint body 32 to the downstream edge portion of the flow path member 2. Therefore, the downstream joint member 4 is formed in a tubular shape.

[0028] The attachment part 33 enables an elastic tube such as a hose to be attached to the main body 1 and has the same function as the attachment part 23. Further, the joint main body 32 guides the liquid flowing in from the hollow part 6 of the flow path member 2 in the hollow part 31 to the attachment part 33. In the present embodiment, the upstream joint member 3 and the downstream joint member 4 have the same shape, and the downstream joint member 4 is also provided with a flange part 24 for preventing the elastic tube from coming off on the outer peripheral surface of the attachment part 33. Further, as shown in FIG. 1, a transition part 35 is formed in the downstream joint member 4. Note that the upstream joint member 3 and the downstream joint member 4 may have different shapes.

[0029] Next, with reference to FIGS. 1 and 2, the operation of the main body 1 of the microbubble generator having the above configuration will be described. When water as a liquid flows into the flow path 5 from the elastic tube attached to the attachment part 23, it is guided to the flow path member 2 through the attachment part 23 of the upstream joint member 3 and the hollow part 21 of the joint main body 22. Then, this water passes through the eccentric long hole 14 of the plate member 10 in the flow path member 2 and flows in a spiral shape while flowing into the reduced part 7 of the hollow part 6, so that the water forms a swirling flow in the space 16 and the flow velocity increases.

[0030] When water flows from the eccentric long hole 14 into the reduced portion 7 here, the periphery of this water is depressurized below atmospheric pressure to become a negative pressure, and the space 16 formed by the reduced portion 7 and the plate member 10 also becomes a negative pressure. At this time, since the water is swirling in the space 16, the water flows in a spiral shape near the outer periphery of the downstream surface 13B of the plate member body 13, while the vicinity of the center of the downstream surface 13B is the center of the swirling flow, so the pressure is even lower than the place near the outer periphery of the downstream surface 13B. Therefore, the location of the inlet 11A of the gas discharge portion 11B, which is on the central axis of the plate member body 13 of the plate member 10 and at a position approximately equidistant from the plurality of eccentric long holes 14, has an even lower pressure than the location near the side wall of the space 16. Gases such as air existing around the main body 1 flow from the air inlet 11D into the gas introduction portion 11C, are guided into the space 16 through the pipe body 11, and flow together with the water in the space 16 toward the fine flow path portion 9. In this way, in the space 16, the inlet 11A is located on the central axis of the plate member 10 or the downstream surface 13B, which is a place where negative pressure is generated when the water is flowing. Therefore, without providing driving means such as an intake pump for inhaling gas from the outside in the main body 1, gas is introduced into the space 16 from outside the main body 1 through the pipe body 11.

[0031] When the water and gas that have flowed into the enlarged portion 8 from the fine flow path portion 9 flow toward the downstream side of the flow path 5, the periphery of this water is depressurized to reach the saturated vapor pressure, and the gas dissolved in the water and the gas flowing together with the water become fine bubbles due to cavitation, thereby generating fine bubbles in the water. Therefore, in addition to the gas dissolved in the water, fine bubbles are also generated from the gas introduced from the pipe body 11, so more fine bubbles are generated than before.

[0032] The water containing these fine bubbles and having an increased amount of vaporized air flows from the enlarged portion 8 into the hollow portion 31 of the downstream joint member 4, and is guided into an elastic tube attached to the attachment portion 33 through the joint body 32 and the attachment portion 33.

[0033] As described above, the main body 1 of the fine bubble generator according to this embodiment is formed with a flow path 5 through which water as a liquid flows inside, and includes a flow path member 2 as a fine bubble generation means for generating fine bubbles in the passing water. The flow path member 2 has a narrowing portion 7 whose cross-sectional area decreases from the upstream side to the downstream side of the flow path 5, an enlarging portion 8 whose cross-sectional area increases from the upstream side to the downstream side, a thin flow path portion 9 formed between the narrowing portion 7 and the enlarging portion 8, and a plate member 10 as a regulating plate for regulating the flow of water. The plate member 10 is formed with an eccentric long hole 14 as a passing hole through which water passes, is disposed on the upstream side of the narrowing portion 7, and includes a pipe body 11 as a gas introduction means. The pipe body 11 is configured to introduce a gas such as air into a space 16 formed by the narrowing portion 7 and the plate member 10 from outside the main body 1.

[0034] By configuring in this way, since fine bubbles are generated not only from the gas dissolved in water but also from the gas introduced from the pipe body 11, it is possible to supply water containing more fine bubbles.

[0035] Also, in the main body 1 of this embodiment, the pipe body 11 is tubular, an inlet 11A for introducing gas into the space 16 faces the downstream side of the flow path 5, and a gas discharge portion 11B as a portion on the inlet 11A side of the pipe body 11 is formed to be parallel to the flow path 5, so that it is possible to easily introduce gas into the space 16 through the pipe body 11.

[0036] Also, in the main body 1 of the present embodiment, the eccentric long hole 14 is provided along the outer periphery of the plate member 10 near the outer periphery, and the positions of the upstream opening and the downstream opening are shifted. The gas introduction port 11A for introducing gas into the space 16 in the pipe body 11 is provided on the central axis of the plate member 10 at a position substantially equidistant from each eccentric long hole 14. For this reason, the flow of the liquid passing through the eccentric long hole 14 can be made into a spiral shape to form a swirling flow, and the flow velocity can be increased to increase the negative pressure region in the space 16. Also, while the water is flowing in a spiral shape near the outer periphery of the downstream surface 13B of the plate member main body 13, since the vicinity of the center of the downstream surface 13B is the center of the swirling flow, the pressure is lower than that in the vicinity of the outer periphery of the downstream surface 13B, and more gas existing around the main body 1 can be introduced into the space 16.

[0037] Also, in the main body 1 of the present embodiment, it is preferable that the gas introduction port 11A for introducing gas into the space 16 in the pipe body 11 is provided flush with the downstream surface 13B of the plate member 10. Since it is a place where the pressure becomes lower in the space 16, a larger amount of gas can be introduced from the outside of the main body 1.

[0038] Also, in the main body 1 of the present embodiment, in the space 16, the gas introduction port 11A is configured to be located at a place where a negative pressure is generated when water is flowing, for example, on the central axis of the plate member 10 or the downstream surface 13B. Even if no driving means such as an intake pump for inhaling gas is provided in the main body 1, gas can be introduced into the space 16 from the outside of the main body 1.

[0039] Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, a through hole 26 for penetrating and connecting the gas introduction portion 11C of the tubular body 11 may be provided in the side wall of the reducing portion 7. At this time, the inlet 11A may be disposed near the central axis of the main body 1 at a position substantially equidistant from the eccentric long hole 14, and the gas discharge portion 11B may be disposed so as to extend parallel to the flow path 5. Further, the eccentric long hole 14 provided in the plate member 10 may be a through hole formed by making the opening positions the same on the upstream surface 13A and the downstream surface 13B of the plate member main body 13. When water flows from the through hole into the reducing portion 7, the periphery of this water is decompressed to below atmospheric pressure and becomes negative pressure, so that the space 16 can also be made negative pressure, and the effects of the main body 1 of the present embodiment can be obtained. And the configuration and shape of each part of the present embodiment are not limited to those shown in the drawings, and can be appropriately changed.

Explanation of Reference Numerals

[0040] 1 Main body (microbubble generator) 2 Flow path member (microbubble generating means) 5 Flow path 7 Reducing portion 8 Enlarging portion 9 Fine flow path portion 10 Plate member (restricting plate) 11 Tubular body (gas introduction means) 11A Inlet 11B Gas discharge portion (portion on the inlet side) 13B Downstream surface 14 Eccentric long hole (through hole) 16 Space

Claims

1. A microbubble generator comprising a microbubble generating means for generating microbubbles in a liquid passing through a flow path formed inside the generator, wherein the microbubble generating means comprises, a constriction portion whose cross-sectional area decreases from the upstream side to the downstream side of the flow path, an expansion portion whose cross-sectional area increases from the upstream side to the downstream side, a thin flow path portion formed between the constriction portion and the expansion portion, and a regulating plate for regulating the flow of the liquid, wherein the regulating plate is provided with a passage hole through which the liquid passes and is disposed on the upstream side of the constriction portion, and is provided with gas introduction means for introducing gas from outside the microbubble generator into the space formed by the constriction portion and the regulating plate.

2. The microbubble generator according to claim 1, wherein the gas introduction means is tubular, an inlet for introducing the gas into the space faces the downstream side, and a portion of the gas introduction means on the inlet side is formed to be parallel to the flow path.

3. A plurality of the passage holes are provided along the outer periphery of the regulating plate near the outer periphery, and the positions of the upstream openings and the downstream openings are shifted, and the inlets for introducing the gas into the space in the gas introduction means are provided at positions equidistant from the respective passage holes.

4. The microbubble generator according to claim 1, wherein the inlets for introducing the gas into the space in the gas introduction means are provided flush with the downstream surface of the regulating plate.

5. The microbubble generator according to any one of claims 2 to 4, wherein in the space, the inlets are located at places where a negative pressure is generated when the liquid is flowing.

Images