Venturi tube

Abstract

To provide a Venturi tube capable of adjusting a mixing amount in which another fluid is actually mixed by a method different from adjustment of a flow passage cross-sectional area.SOLUTION: The flow path through which the first fluid flows in the main body 10 of the venturi tube 1 is divided into a decreasing flow path 11 in which the flow path cross-sectional area gradually decreases from the upstream side, a throat portion flow path 12 in which a portion having a minimum flow path cross-sectional area exists, and an increasing flow path 13 in which the flow path cross-sectional area gradually increases. A supply portion 16 for mixing the second fluid with the first fluid is disposed on a wall surface of the throat portion flow path 12 of the main body 10. The supply part 16 includes an injection quantity adjusting part 19 capable of adjusting an insertion quantity into the throat part flow passage 12 of an injection nozzle 17 for injecting the second fluid into the first fluid.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a Venturi tube. [Background technology]

[0002] A Venturi tube narrows the cross-sectional area of ​​a fluid flow path, constricting the flow of the fluid and increasing the flow velocity. This increases the pressure drop that accompanies the increase in flow velocity, and is used to mix another fluid with the constricted fluid. The amount of another fluid that can be mixed depends on the amount of pressure drop. The appropriate amount of mixing varies depending on the combination of fluids to be mixed, the application, etc. For this reason, some Penturi tubes have variable cross-sectional areas of the flow path to allow the amount of mixing to be adjusted (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-158621 Summary of the Invention [Problem to be solved by the invention]

[0004] The amount of another fluid that is actually mixed varies depending on the state of each fluid at the time, such as temperature or air pressure (for example, the static pressure difference between two fluids), etc. Because of this, it seems important to consider measures other than adjusting the cross-sectional area of ​​the flow path in order to be able to appropriately control the amount of another fluid that is actually mixed.

[0005] Therefore, the present invention proposes a Venturi tube that can adjust the amount of another fluid actually mixed by a method other than adjusting the cross-sectional area of ​​the flow path. [Means for solving the problem]

[0006] A Venturi tube according to one embodiment of the present disclosure includes a supply unit disposed between an inlet through which a first fluid flows and an outlet through which the first fluid flows, for supplying a second fluid to be mixed with the first fluid to the first fluid, and a position change unit that enables the position of the supply unit to be changed in a direction intersecting the direction in which the first fluid flows. [Effects of the Invention]

[0007] In the present invention, the amount of another fluid actually mixed can be adjusted by a method other than adjusting the cross-sectional area of ​​the flow path. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a side cross-sectional view showing a Venturi tube according to a first embodiment of the present invention. [Figure 2] FIG. 1 is a front view showing a Venturi tube according to a first embodiment of the present invention. [Figure 3] FIG. 3 is a cross-sectional view taken along the line AA′ shown in FIG. 2. [Figure 4] FIG. 6 is a side cross-sectional view showing a Venturi tube according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. Note that each embodiment described below is merely an example, including modified examples, and the technical scope of the present invention is not limited to this. Various modified examples are also included within the technical scope of the present invention.

[0010] FIG. 1 is a side cross-sectional view showing a Venturi tube according to a first embodiment of the present invention, and FIG. 2 is a front view showing the Venturi tube. The Venturi tube 1 shown in Figure 1 is used to narrow the cross-sectional area of ​​the flow path of the fluids to be mixed, increasing the flow velocity of the fluid, and then mix another fluid into the narrowed flow by utilizing the decrease in pressure that accompanies this increase in flow velocity. To avoid confusion, hereafter, the fluid to be mixed will be referred to as the "first fluid" and the fluid to be mixed with the first fluid will be referred to as the "second fluid."

[0011] As shown in FIGS. 1 and 2 , the main body 10 of the Venturi tube 1 according to this embodiment has an overall rectangular columnar external shape, with the longitudinal direction being the direction in which the first fluid flows. The flow path through the main body 10, through which the first fluid flows, can be divided, from the upstream side, into a reduced flow path 11 in which the cross-sectional area of ​​the flow path gradually decreases, a throat (throat) flow path 12 in which the cross-sectional area of ​​the flow path is minimum, and an expanded flow path 13 in which the cross-sectional area of ​​the flow path gradually increases. As a result, the Venturi tube 1 is configured such that the first fluid flows in through the reduced flow path 11 and then flows out through the expanded flow path 13. In other words, the upstream opening of the reduced flow path 11 is the inlet, and the downstream opening of the expanded flow path 13 is the outlet. The front view shown in FIG. 2 is a view of the first fluid as viewed from the upstream side to the downstream side.

[0012] The cross-sectional area of ​​the flow path here is, for example, the area of ​​a plane perpendicular to a line (hereinafter referred to as "center line") connecting the inlet for the first fluid, i.e., the center of the opening on the most upstream side of the reduced flow path 11, and the outlet for the first fluid, i.e., the center of the opening on the most downstream side of the expanded flow path 13. The definition of the cross-sectional area of ​​the flow path may be determined depending on the structure of the Venturi tube 1, i.e., the shape of the flow path through which the first fluid flows, etc.

[0013] Plate-like protrusions 14, 15 that protrude away from the center line are disposed on the most upstream side of the reduced flow path 11 and the most downstream side of the expanded flow path 13 of the main body 10. These protrusions 14, 15 are used to connect pipes or the like to the Venturi tube 1. As shown in FIG. 2, the protrusion 14 has a plurality of holes 14a for connecting pipes or the like. The same applies to the protrusion 15.

[0014] A supply unit 16 for mixing the second fluid with the first fluid is arranged on the wall surface of the throat flow path 12 of the main body 10. The supply unit 16 enables the second fluid to be supplied into the first fluid. The supply unit 16 is broadly divided into an injection nozzle 17 for injecting the second fluid into the first fluid, an injection nozzle 18 for injecting the second fluid, and an injection amount adjustment unit 19 for supplying the second fluid injected into the injection nozzle 18 to the injection nozzle 17. A through-hole 20 is formed in the supply unit 16, penetrating the injection nozzle 18, the injection amount adjustment unit 19, and the injection nozzle 17, so that the second fluid injected from the injection nozzle 18 can be injected from the injection nozzle 17.

[0015] The injection amount adjustment portion 19 is roughly divided into an insertion target portion 19a that is intended to be inserted into the throat flow path 12, and an insertion amount adjustment portion 19b that makes it possible to adjust the amount of insertion of the insertion target portion 19a into the throat flow path 12. To clearly show the insertion target portion 19a and the insertion amount adjustment portion 19b, the boundaries between these portions are shown by solid lines in Figure 1.

[0016] The insertion amount adjustment portion 19b has a cylindrical external shape as a whole, and a male screw (not shown) is formed on the entire outer circumferential surface thereof. The outer shape of the insertion amount adjustment portion 19b is different from that of the insertion target portion 19a. Due to the difference in shape, as shown in FIG. 1, the main body 10 is formed with a hole 21 for allowing the insertion target portion 19a to move in a direction intersecting the center line, for example, in a direction perpendicular to the center line.

[0017] A through hole 22 conforming to the shape of the insertion target portion 19a is formed between the bottom of the hole 21 and the wall surface of the throat flow path 12. The insertion target portion 19a is guided by this through hole 22 and is able to move in the intersecting direction. A gasket 23 is attached to the through hole 22 near the wall surface of the throat flow path 12. This gasket 23 can prevent leakage of the first fluid and mixing of the atmosphere with the first fluid. Hereinafter, this intersecting direction will be referred to as the "movement direction." Furthermore, the direction in which the portion of the insertion target portion 19a present in the throat flow path 12 becomes longer will be referred to as the "insertion direction," and the opposite direction will be referred to as the "removal direction." The movement direction corresponds to the intersecting direction in this embodiment.

[0018] By inserting the insertion target portion 19a into the through-hole 22, the position of the injection amount adjustment portion 19 is restricted so that it does not change in a direction intersecting the movement direction. The position of the injection amount adjustment portion 19 in the movement direction is restricted by the support member 25 and two nuts 27 and 28. Specifically, the nut 27 restricts the movement of the injection amount adjustment portion 19 in the insertion direction, and the nut 28 restricts the movement of the injection amount adjustment portion 19 in the removal direction.

[0019] Both nuts 27, 28 have a female thread (not shown) formed on their inner circumferential surfaces. The male thread formed on the outer circumferential surface of the insertion amount adjustment portion 19b is shaped to screw into, or mesh with, the female thread. Such nuts 27, 28 are attached to the insertion amount adjustment portion 19b, which is inserted into a hole 25a formed in the support member 25, in a manner that sandwiches the support member 25. Therefore, by sandwiching the support member 25 between the nuts 27, 28, the position of the injection amount adjustment portion 19 in the movement direction is restricted so that it does not change.

[0020] Changing the relative positional relationship between the nuts 27, 27 on the insertion amount adjustment portion 19b changes the relative positional relationship between the support member 25 and the injection amount adjustment portion 19. As a result, the user can adjust the position of the injection nozzle 17 in the throat flow path 12, i.e., the insertion amount of the injection nozzle 17 into the throat flow path 12, by changing the relative positional relationship between the nuts 27, 27 on the insertion amount adjustment portion 19b.

[0021] The support member 25 is detachably attached to the main body 10 by, for example, screws 26 so that the nuts 27 and 28 can be attached to the insertion amount adjustment portion 19b with the support member 25 sandwiched between them. Thus, the nut 28 can be attached to the insertion amount adjustment portion 19b without the support member 25 being attached to the main body 10. The nut 27 can be attached to the insertion amount adjustment portion 19b with the insertion amount adjustment portion 19b after the nut 28 is attached inserted into the hole 25a. The support member 25 can be attached to the main body 10 either with the insertion amount adjustment portion 19b after the nut 28 is attached inserted into the hole 25a, or with the nut 27 attached to the insertion amount adjustment portion 19b. In either state, the insertion target portion 19a is assumed to be inserted into the through-hole 22.

[0022] As described above, the support member 25, the plurality of screws 26, and the two nuts 27, 28 correspond to a position change unit in this embodiment that changes the position of the supply unit 16 in the movement direction. Note that this position change unit may be electrically operated to change the position in the movement direction. The position may be changed automatically based on the result of identifying the result of mixing the second fluid with the first fluid. Various modifications, including those described above, are possible.

[0023] In this embodiment, as described above, by making the position of the injection amount adjustment unit 19 in the movement direction variable, the position of the injection nozzle 17 in the movement direction, i.e., the injection of the second fluid into the first fluid, can be adjusted. This is because the amount of the second fluid that can be mixed with the first fluid changes depending on the position of the injection nozzle 17 in the movement direction. Thus, in this embodiment, the position of the injection nozzle 17 in the movement direction can be adjusted depending on the amount of the second fluid to be mixed.

[0024] As shown in Figure 1, the side shape of the support member 25 has a recess in the center that is away from the main body 10. A hole 21 is formed on the main body 10 side facing the recess. This structure is intended to increase the range over which the insertion amount adjustment portion 19b can move. This increases the range over which the position of the injection nozzle 17 in the movement direction can be adjusted.

[0025] The further the injection nozzle 17 is inserted in the insertion direction, the greater the proportion of the first fluid that exists between the injection nozzle 17 and the wall surface of the main body 10 on the side from which the insertion target portion 19a protrudes. It is believed that the greater this proportion, the greater the proportion of the first fluid that contributes to mixing with the second fluid. It is believed that the greater this proportion of the first fluid, the greater the efficiency with which the second fluid is mixed with the first fluid. Therefore, it is believed that the position of the injection nozzle 17 in the movement direction can control the amount of the second fluid that is actually mixed with the first fluid.

[0026] In this embodiment, the cross-sectional area of ​​the flow path through which the first fluid flows varies depending on the position of the jet nozzle 17 in the movement direction, as shown in FIG. 2, depending on the insertion target portion 19a. The further the jet nozzle 17 is inserted in the insertion direction, the narrower the cross-sectional area of ​​the flow path becomes, and the faster the flow rate of the first fluid becomes. This also makes it possible to control the amount of the second fluid actually mixed with the first fluid depending on the position of the jet nozzle 17 in the movement direction. This mixing amount can be made larger compared to when the cross-sectional area of ​​the flow path is simply adjusted.

[0027] For example, if the first fluid is water and the second fluid is air, the amount of air mixed into the water can be changed (adjusted) depending on the position of the injection nozzle 17 in the direction of movement. As a result, in this case, the amount of fine bubbles generated in the water can be adjusted depending on the position of the injection nozzle 17 in the direction of movement. Among the fine bubbles, microbubbles are defined as bubbles with a diameter of 1 to 100 μm according to the ISO (International Organization for Standardization) standard. Although the strict definition of nanobubbles varies depending on the application field and generation method, nanobubbles are generally considered to be bubbles with a diameter of 1 μm or less. The first fluid and the second fluid may be either a liquid or a gas.

[0028] The position of the supply unit 16 shown in Fig. 1 is a reference position. The front view shown in Fig. 2 is a view of the Venturi tube 1 from the upstream side of the first fluid. Fig. 2 shows the supply unit 16 moved in the insertion direction from the reference position. 2, in this embodiment, the shape of the insertion target portion 19a relative to the cross-sectional area of ​​the flow path is rectangular, and its width in the direction perpendicular to the movement direction is larger than that of the jet nozzle 17. The reason why such a shape is adopted for the insertion target portion 19a is to use the insertion target portion 19a to reduce the cross-sectional area of ​​the flow path as the position of the jet nozzle 17 moves in the insertion direction, thereby increasing the flow rate of the first fluid. By increasing the flow rate of the first fluid, the amount of the second fluid that can be mixed with the first fluid can be increased.

[0029] 3 is a cross-sectional view taken along line A-A' in FIG. 2. W in FIG. 3 is the width in the orthogonal direction that is parallel to the cross-sectional area of ​​the flow path of the insertion target portion 19a and perpendicular to the movement direction. Since W is the maximum width, it will be referred to as the "maximum width W" hereinafter. The orthogonal direction perpendicular to the movement direction in which this maximum width W is obtained will also be referred to as the "width direction."

[0030] In this embodiment, as shown in FIG. 3 , the width of the insertion target portion 19a narrows in the direction of flow of the first fluid after reaching a maximum width W. More specifically, the cross-sectional shape of the insertion target portion 19a narrows at an acute angle after reaching the maximum width W. That is, the angle formed by the cross-sectional shape at the end 31 where the maximum width W is reached is an acute angle. This cross-sectional shape is adopted so that the first fluid deviates from the insertion target portion 19a at the end 31 where the maximum width W is reached and becomes a vortex. The pressure drop caused by the first fluid becoming a vortex can increase the amount of the second fluid that can be mixed with the first fluid. For this reason, it is effective to give the insertion target portion 19a a cross-sectional shape that generates or easily generates a vortex.

[0031] The cross-sectional shape of the insertion target portion 19a up to the maximum width W in the direction of flow of the first fluid (hereinafter referred to as the "full-surface cross-sectional shape") is curved, more specifically, convex toward the upstream side, in order to reduce resistance, particularly wave-making resistance. In cases where such resistance can be ignored, the full-surface cross-sectional shape may be flat. Including such a modification, various modifications of the cross-sectional shape of the insertion target portion 19a are possible.

[0032] In this embodiment, only one supply unit 16 is provided, but multiple supply units 16 may be provided. When multiple supply units 16 are provided, it is not necessary for all of them to have adjustable positions of the injection nozzles 17. In other words, only one or more supply units 16 may have adjustable positions of the injection nozzles 17, while the other supply units 16 may have fixed positions of the injection nozzles 17.

[0033] In the first embodiment, the position of the injection nozzle 17 within the throat flow path 12 is adjustable, thereby making it possible to adjust the amount of the second fluid actually mixed with the first fluid and to increase the amount of the second fluid to be mixed. In contrast, the second embodiment further makes it possible to more appropriately mix the amount of the second fluid with the first fluid. Hereinafter, for easier understanding, it is assumed that the first fluid is a liquid and the second fluid is a gas unless otherwise specified.

[0034] FIG. 4 is a side cross-sectional view showing a Venturi tube according to a second embodiment of the present invention. Similar to the first embodiment, a Venturi tube 100 according to a second embodiment shown in FIG. 4 is used to narrow the cross-sectional area of ​​the flow path of a first fluid, increase the flow velocity of the first fluid, and mix a second fluid with the first fluid whose flow velocity has been increased. In the second embodiment, the Venturi tube 1 according to the first embodiment is used as a component, and another Venturi tube 40 is connected in series to the Venturi tube 1, thereby realizing the Venturi tube 100. To avoid confusion, the Venturi tubes 1 and 40, which are components, will be referred to as the "first Venturi tube section 1" and the "second Venturi tube section 40," respectively.

[0035] The first Venturi tube portion 1 is the same as or basically the same as that in the first embodiment, so here, a description of the first Venturi tube portion 1 will basically be omitted and the description will focus on the rest.

[0036] As shown in Fig. 4, the main body 41 of the second Venturi tube section 40 has an overall rectangular columnar appearance. The main body 41 is provided with a connecting section 42 for connection to the first Venturi tube section 1. As a result, the main body 41 can be divided into the following flow paths through which the first fluid flows: a connecting flow path 43 formed by the connecting section 42 that allows the first fluid (mixed with the second fluid) to flow in from the first Venturi tube section 1, an inflow flow path 44 through which the first fluid flows from the connecting flow path 43, a throat flow path 45 where the cross-sectional area of ​​the flow path is at its minimum, and an expanding flow path 46 where the cross-sectional area of ​​the flow path gradually expands.

[0037] The main body 41 has an opening 44b that is intended to allow the first fluid to flow in from a location other than the connecting portion 42. The first fluid that flows in from the opening 44b flows through the inlet flow path 44. The downstream side of the inlet flow path 44 is a reduced flow path 44a in which the cross-sectional area of ​​the flow path gradually decreases. As a result, the first fluid flowing through the inlet flow path 44 has its flow velocity increased by the reduced flow path 44a, and then flows through the throat flow path 45.

[0038] A plate-shaped protruding portion 47 that protrudes in a direction away from the center line is disposed on the most upstream side of the connecting portion 42. This protruding portion 47 is intended for connection to the first Venturi tube portion 1. This protruding portion 47 is formed to match the shape of the protruding portion 15 provided on the first Venturi tube portion 1, and has screw holes formed therein that match the arrangement of the holes (not shown) provided in the protruding portion 15. Therefore, as shown in FIG. 4, the first Venturi tube portion 1 can be attached, or connected, to the second Venturi tube portion 40 by using screws 48 inserted from the protruding portion 15 side.

[0039] The center line here refers to, for example, a line connecting the center of the opening 44b and the center of the outlet for the first fluid, i.e., the center of the opening on the most downstream side of the expanded flow path 46. The flow path cross-sectional area is the area of ​​a plane perpendicular to the center line. The definitions of the center line and the flow path cross-sectional area may be determined depending on the structure of the second Venturi tube section 40, i.e., the shape of the flow path through which the first fluid flows, etc.

[0040] A plate-shaped protruding portion 49 that protrudes in a direction away from the center line is disposed on the most downstream side of the main body 41. This protruding portion 49 is for connecting a pipe or the like to the Venturi tube 100, i.e., the second Venturi tube portion 40. Like the protruding portions 14 and 15, this protruding portion 49 also has a plurality of holes (not shown) for connecting to a pipe or the like.

[0041] In the Venturi tube 100 having a configuration in which the first Venturi tube section 1 is connected to the second Venturi tube section 40, the first fluid that flows from the first Venturi tube section 1 into the second Venturi tube section 40 flows through the inlet flow passage 44, the throat flow passage 45, and the diverging flow passage 46. The flowing first fluid is converged as it flows from the inlet flow passage 44 to the throat flow passage 45. When flowing through the throat flow passage 45, the flow velocity of the first fluid reaches a maximum, and the pressure decreases.

[0042] Assuming that the first fluid is a liquid and the second fluid is a gas, relatively large bubbles present in the first fluid flowing into the second Venturi tube section 40 will break down into smaller bubbles as they flow through the throat flow path 45. When the first Venturi tube section 1 and the second Venturi tube section 40 are connected so that their centerlines intersect, as shown in FIG. 4, turbulence occurs in the flow of the first fluid flowing from the first Venturi tube section 1. This flow turbulence promotes the breakup of large bubbles into smaller bubbles. For this reason, connecting the first Venturi tube section 1 to the second Venturi tube section 40 so that their centerlines intersect, as shown in FIG. 4, is effective in achieving more optimal mixing of the first and second fluids.

[0043] The first fluid flowing toward the throat flow path 45 flows along the narrowing flow path 44a of the inlet flow path 44, and is thereby converged. Therefore, during convergence, a force is applied to the first fluid in a direction intersecting the center line. This force acts to make the bubbles present in the first fluid smaller. As a result, by flowing the first fluid into the throat flow path 45, the first fluid and the second fluid are mixed in a more appropriate state.

[0044] By making the first fluid and the second fluid more appropriately mixed, there is room for the second fluid to be further appropriately mixed with the first fluid. For this reason, in this embodiment, as shown in Fig. 4, an injection nozzle 50 is disposed on the wall surface of the throat flow path 45 of the main body 41. This injection nozzle 50 is for further mixing the second fluid with the first fluid.

[0045] A through hole 51 is formed in the injection nozzle 50. This through hole 51 extends to an injection nozzle 52 arranged outside the main body 41. As a result, the second Venturi tube portion 40 is able to mix the first fluid flowing through the throat flow path 45 with the second fluid injected from the injection nozzle 52 by injecting the second fluid from the injection nozzle 52 from the injection nozzle 50.

[0046] By enabling the second fluid to be injected from the injection nozzle 50, it is possible to appropriately mix the first fluid and the second fluid while more easily maximizing the amount of the second fluid mixed with the first fluid. This means that, for example, when the first fluid is water and the second fluid is air, a larger amount of fine bubbles can be generated in the water.

[0047] The second Venturi tube section 40 functions as an agitator to generate a larger amount of such fine bubbles. For this reason, it is effective to arrange the first Venturi tube section 1 upstream of the second Venturi tube section 40, as shown in FIG. 4. Two or more Venturi tubes that are used as agitators may be connected as a Venturi tube section. When connecting two Venturi tube sections, it is desirable to connect them so that their center lines intersect, as shown in FIG. 4. However, when connecting two or more Venturi tube sections, it is not necessary to connect them so that their center lines intersect.

[0048] The force acting on the first fluid in a direction intersecting the center line, i.e., the agitating force of the first fluid, depends on the size of the flow path cross-sectional area of ​​the throat flow path 45. For this reason, in the second embodiment, the size of the flow path cross-sectional area of ​​the throat flow path 45 is made adjustable. The adjustment member 53 is provided for this purpose.

[0049] 4, adjustment member 53 is located on the throat flow path 45 side and is roughly divided into a pointed tip portion 53a, a rod-shaped portion 53b that continues from tip portion 53a and has a rod-like shape overall, a threaded portion 53c that continues from rod portion 53b and has a male screw (not shown) formed on its surface, and a knob portion 53d that is operated by the user. This adjustment member 53 is supported by a plate-shaped member 54 attached so as to cover opening 44b and a support member 55 so as to be movable along the center line.

[0050] The plate-shaped member 54 has a through-hole through which the tip portion 53a and rod-shaped portion 53b of the adjustment member 53 can pass. A packing 56 is attached near the end of the through-hole on the opening 44b side. A hole 54a is formed on the opposite side of the plate-shaped member 54. The packing 56 is in close contact with the rod-shaped portion 53b and prevents both the first fluid and the second fluid from leaking from the through-hole. The hole 54a is provided to increase the range over which the threaded portion 53c can move toward the throat portion.

[0051] The support member 55 is a member that employs a side shape similar to that of the support member 25. A through hole 55c is formed in the bottom portion of the recess, and a nut 55b is fixedly attached to the opposite side of the main body 41, aligned with the position of the through hole 55c. A female thread that screws into the threaded portion 53c of the adjustment member 53 is formed on the inner surface of the nut 55b. As a result, the adjustment member 53 is supported by the support member 55 by inserting the tip portion 53a from the opposite side of the main body 41 and screwing the threaded portion 53c into the nut 55b.

[0052] A plate-shaped protruding portion 57 that protrudes in a direction away from the center line is disposed at the end of the main body 41 on the opening 44b side. This protruding portion 57 is provided with a plurality of holes (not shown) with, for example, female threads formed therein. As shown in FIG. 4, the plate-shaped member 54 is shaped to cover the protruding portion 57, and through holes are formed in the plate-shaped member 54 to match the positions of the holes formed in the protruding portion 57. The support member 55 is also shaped to cover the protruding portion 57, and through holes are formed in the plate-shaped member 54 to match the positions of the holes formed in the protruding portion 57.

[0053] For this reason, as shown in Fig. 4, the plate-shaped member 54 and the support member 55 can be attached to the main body 41 by aligning the positions of the holes in the plate-shaped member 54, the support member 55, and the protrusion 57 and inserting a screw 58 from the support member 55 side. When attaching in this manner, the adjustment member 53 is first screwed onto the nut 55b of the support member 55, and then the tip portion 53a is inserted into the through-hole of the plate-shaped member 54. This allows the second Venturi tube unit 40 to be assembled in the state shown in Fig. 4. The adjustment member 53 is supported by the plate-shaped member 54 and the support member 55.

[0054] The nut 55b is finally attached so that its inner surface is aligned with the centerline. Therefore, the adjustment member 53 is attached in a state where it can move along the centerline by rotating the knob portion 53d. The tip portion 53a has a pointed cross-sectional shape. Therefore, the more the adjustment member 53 is moved toward the throat, the smaller the flow path cross-sectional area of ​​the throat flow path becomes.

[0055] Therefore, by moving the adjusting member 53 along the center line, the flow path cross-sectional area of ​​the throat flow path can be adjusted. Adjusting the flow path cross-sectional area of ​​the throat flow path means that both the stirring force on the first fluid and the pressure of the first fluid can be adjusted. As a result, the second fluid can be mixed with the first fluid more appropriately, and the amount of the second fluid to be mixed can also be increased. When generating microbubbles in water, a larger amount of microbubbles can be generated.

[0056] The flow path cross-sectional area of ​​the throat flow path is adjusted mainly by the adjustment member 53, the plate-like member 54, and the support member 55. Therefore, these correspond to the adjustment unit in this embodiment. This adjustment unit may be capable of automatically adjusting the flow path cross-sectional area of ​​the throat flow path in accordance with the state of the first fluid flowing out of the second Venturi tube portion 40. Various other modifications are also possible.

[0057] In this embodiment, the flow path cross-sectional area of ​​the throat flow path 45 of the second Venturi tube portion 40 is adjustable, but the second Venturi tube portion 40 may have a non-adjustable flow path cross-sectional area. For example, a conventional Venturi tube or a similar device may be used. A device similar to the first Venturi tube portion 1 may also be used. Regardless of which device is used, the second Venturi tube portion 40 can increase the amount of the second fluid that can be mixed with the first fluid.

[0058] The second Venturi tube portion 40 does not have to be used to supply the second fluid. In other words, the second Venturi tube portion 40 may simply be used as an agitation portion that agitates the first fluid. Even if the second Venturi tube portion 40 is simply used as an agitation portion, the agitation action of the second Venturi tube portion 40 can more appropriately mix the second fluid with the first fluid. Any agitation portion can be used as long as it can agitate the first fluid. For this reason, a wide variety of agitation portions that provide resistance to the first fluid can be used.

[0059] The flow velocity of the first fluid in the throat passage 12 of the first Venturi tube section 1 depends on the magnitude relationship between the passage cross-sectional area of ​​the throat passage 12 and the passage cross-sectional area of ​​the throat passage 45 of the second Venturi tube section 40. Due to this dependency, it is desirable that the maximum passage cross-sectional areas of the throat passages 12, 45 of the first Venturi tube section 1 and the second Venturi tube section 40 satisfy the following relationship: Maximum cross-sectional area of ​​throat flow passage 12 < Maximum cross-sectional area of ​​throat flow passage 45

[0060] Furthermore, in this embodiment, the first Venturi tube section 1 is the same as that of the first embodiment, but a conventional Venturi tube or the second Venturi tube section 40 may also be used as the first Venturi tube section 1. Regardless of which type is used as the first Venturi tube section 1, the second Venturi tube section 40 (agitation section) located downstream can more appropriately mix the second fluid with the first fluid. Furthermore, the amount of the second fluid that can be mixed with the first fluid can be increased.

[0061] Alternatively, an ordinary pipe may be used as the first Venturi tube portion 1. In this case, the first fluid and the second fluid may be flowed through the pipe. It is not necessary to pre-mix these fluids. This is because the fluids are agitated and mixed while flowing to the throat flow path 45. There is no particular limitation as to whether or not the second fluid is further supplied to the second Venturi tube portion 40. Many variations, including those mentioned above, are possible. [Explanation of symbols]

[0062] 1 Venturi tube, first Venturi tube portion, 10, 41 main body, 16 supply portion, 17, 50 injection nozzle, 18, 52 injection nozzle, 19 injection amount adjustment portion, 19a insertion target portion, 19b insertion amount adjustment portion, 20 through hole, 40 second Venturi tube portion, 53 adjustment member.

Claims

1. a supply unit that is disposed between an inlet through which a first fluid flows in and an outlet through which the first fluid flows out, and that supplies a second fluid to be mixed with the first fluid to the first fluid; a position change unit that changes the position of the supply unit in a direction intersecting the direction in which the first fluid flows; A Venturi tube equipped with a

2. the supply unit includes a nozzle that can supply the second fluid, and an insertion target portion in which the nozzle is arranged, the insertion target portion being parallel to a flow path cross-sectional area of ​​the first fluid and having a width in an orthogonal direction orthogonal to the intersecting direction that is larger than the nozzle; 10. The Venturi tube of claim 1.

3. The insertion target portion has a cross-sectional shape that narrows from a position where the width in the direction perpendicular to the flow of the first fluid is maximum.

3. The Venturi tube of claim 2.

4. Further provided is a stirring unit that stirs the first fluid mixed with the second fluid. A Venturi tube according to any one of claims 1 to 3.

5. The stirring unit is a venturi tube separate from the venturi tube.

5. The Venturi tube of claim 4.

6. The other Venturi tube includes an adjustment portion that can adjust a flow path cross-sectional area of ​​a throat portion.

6. The Venturi tube of claim 5.

7. a first venturi tube capable of supplying a second fluid to a first fluid and mixing the first fluid with the second fluid; a second Venturi tube capable of supplying the second fluid to the first fluid from the first Venturi tube and further mixing the second fluid with the first fluid; A Venturi tube equipped with a

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