Gas-liquid mixing apparatus and liquid apparatus

Abstract

It can efficiently dissolve gases in liquids. [Solution] The device comprises a first cylindrical section, an upper plate covering the upper end of the first cylindrical section, and a lower plate covering the lower end of the first cylindrical section, a mixing section in which a liquid to be treated, a mixture of liquid and gas, is stored, an inlet section provided on the upper plate for introducing the liquid to be treated into the mixing section, and an outlet section provided on the lower plate for releasing the liquid to be treated from the mixing section. The first central axis, which is the central axis of the first cylindrical section, is inclined with respect to the vertical direction. The inlet section has a first hole provided on the upper plate, a hollow direction-changing section provided inside the mixing section so as to cover the first hole, and an injection hole provided in the direction-changing section. The area of ​​the injection hole is smaller than the area of ​​the first hole, and the injection hole is located in an area that can be seen when the direction-changing section is viewed from the vertically downward side.

Description

Technical Field

[0001] The present invention relates to a gas-liquid mixing treatment device and a liquid treatment device.

Background Art

[0002] [[ID=Z11]] Patent Document 1 discloses a gas dissolution device that stores gas and liquid in a cylindrical body and injects a gas-liquid mixed fluid in which gas and liquid are mixed in the cylindrical body to dissolve the gas in the liquid. In this gas dissolution device, the cylindrical body is arranged such that its central axis is inclined with respect to the horizontal direction, and the interface between the gas and liquid stored inside is positioned at the middle part of the substantially cylindrical side wall portion of the cylindrical body. The upper and lower portions of the cylindrical body above and below the interface are respectively used as a gas storage portion and a liquid storage portion, and an injection port for injecting the gas-liquid mixed fluid into the gas storage portion in the cylindrical body is provided at the same level or slightly below the level of the interface of the cylindrical body. An outlet for allowing the liquid in the cylindrical body to flow out is provided near the lower end portion of the cylindrical body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the invention described in Patent Document 1, the gas-liquid mixed fluid is directly injected into the cylindrical body from the inflow pipe, and there is a possibility that the gas may not be efficiently dissolved in the liquid.

[0005] In view of such circumstances, the present invention has been made, and an object thereof is to provide a gas-liquid mixing treatment device and a liquid treatment device capable of efficiently dissolving gas in liquid.

Means for Solving the Problems

[0006] To solve the above problems, the gas-liquid mixing apparatus according to the present invention comprises, for example, a first cylindrical part, an upper plate covering the upper end of the first cylindrical part, and a lower plate covering the lower end of the first cylindrical part, a mixing part in which a liquid to be processed, which is a mixture of liquid and gas, is stored, an inlet part provided on the upper plate for introducing the liquid to be processed into the mixing part, and an outlet part provided on the lower plate for introducing the liquid to be processed out of the mixing part, wherein the first central axis, which is the central axis of the first cylindrical part, is inclined with respect to the vertical direction, the inlet part comprises a first hole provided on the upper plate, a hollow direction-changing part provided inside the mixing part so as to cover the first hole, and an injection hole provided in the direction-changing part, wherein the area of ​​the injection hole is smaller than the area of ​​the first hole, and the injection hole is provided in a region that can be seen when the direction-changing part is viewed from the vertically downward side.

[0007] According to the above embodiment of the present invention, a mixing section in which the liquid to be treated is stored is arranged such that the first central axis, which is the central axis of the first cylindrical section, is inclined with respect to the vertical direction. The liquid to be treated is introduced into a hollow direction-changing section located inside the mixing section, which covers a first hole provided in the upper plate, and the liquid to be treated is injected into the mixing section from an injection hole provided in the direction-changing section. Since the area of ​​the injection hole is smaller than the area of ​​the first hole, the flow velocity of the liquid to be treated injected from the injection hole is increased. Furthermore, since the injection hole is located in an area that can be seen when the direction-changing section is viewed from below in the vertical direction, the liquid to be treated enters the liquid surface at an oblique angle, and the gas and liquid are efficiently mixed near the liquid surface. This makes it possible to efficiently dissolve the gas in the liquid.

[0008] The direction-changing section has a cylindrical second tubular section with one end in contact with the upper plate, and an end portion that covers the end of the second tubular section that is not in contact with the upper plate. The second central axis, which is the central axis of the second tubular section, is aligned with the first direction, which is the extending direction of the first central axis. The injection holes may be provided in the lower half of the side surface of the second tubular section. This allows the direction-changing section to have a shape that makes it easy to position the injection holes appropriately. It also allows the structure to be such that the liquid to be treated, injected from the injection holes, is easily incident on the liquid surface at an oblique angle.

[0009] When the direction-changing portion is cut by a plane perpendicular to the first direction, the angle between the first line, which is a line that lies along the second direction perpendicular to the first direction and the horizontal direction and passes through the second central axis, and the second line, which is a line connecting the second central axis and the center of the injection hole, may be approximately 45 degrees. This significantly increases the dissolution ratio and allows the gas to be dissolved in the liquid efficiently.

[0010] The second cylindrical portion is provided with a plurality of injection holes, the total area of ​​the injection holes being less than or equal to the area of ​​the first hole, and when the direction changing portion is cut by a plane perpendicular to the first direction, the second line may be positioned symmetrically with respect to the first line. This increases the amount of liquid to be treated that is incident on the liquid surface at a desired angle, and allows the gas to be efficiently dissolved in the liquid.

[0011] The center of the first hole may be located below the first central axis. This reduces the distance from the injection hole to the liquid surface, increasing surface roughness due to the liquid being treated hitting the surface, and allowing for efficient mixing of gas with the liquid.

[0012] The outlet section has a second hole formed in the lower plate, and the center of the second hole may be located below the first central axis. This increases the height from the outlet section to the liquid surface, making it more difficult for excess bubbles to flow out of the outlet section.

[0013] To solve the above problems, the liquid processing apparatus according to the present invention comprises, for example, a gas-liquid mixing apparatus as described above, a flow path through which the liquid to be processed flows, the flow path in which the gas-liquid mixing apparatus is provided, a pump provided on the upstream side of the flow path of the gas-liquid mixing apparatus, and a gas intake section provided on the upstream side of the flow path of the pump for mixing gas with the liquid to be processed, wherein the pump causes the liquid to be processed to flow into the gas intake section and causes the liquid that has passed through the gas intake section to flow into the gas-liquid mixing apparatus. This makes it possible to efficiently dissolve gas in liquid.

[0014] The system may also include a liquid level acquisition unit that acquires the height of the liquid being treated in the first cylindrical section, and a control unit that adjusts the flow rate of gas in the gas intake section based on the acquisition result from the liquid level acquisition unit. This allows for efficient mixing of gas with the liquid by adjusting the amount of gas input in the gas intake section according to the degree of gas solubility. Furthermore, it is possible to reduce the amount of excess gas input and conserve gas.

[0015] The first cylindrical portion is formed using a transparent material, and the liquid level acquisition unit may include an imaging unit that acquires an image of the inside of the first cylindrical portion. This allows the liquid level to be acquired by observing the image, and enables adjustment of the amount of gas to be introduced with a simple device configuration. [Effects of the Invention]

[0016] According to the present invention, a gas can be efficiently dissolved in a liquid. [Brief explanation of the drawing]

[0017] [Figure 1] This is a schematic diagram showing an example of a liquid processing apparatus 2 including a gas-liquid mixing apparatus 1. [Figure 2] This diagram shows a schematic of the gas-liquid mixing apparatus 1, where (A) is a front view and (B) is a view taken along arrow A in (A). [Figure 3] This is a schematic cross-sectional view of the gas-liquid mixing apparatus 1. [Figure 4] It is a view seen from the direction of arrow B in FIG. 3. [Figure 5] It is a schematic cross-sectional view of the cylindrical portion 14d. [Figure 6] It is a view showing an example of the form of the injection hole according to the modification, (a) is a view seen from the -z direction, and (b) is a schematic cross-sectional view of the cylindrical portion 14d. Also, (A) to (D) respectively show the schematics of the inflow portions 14A to 14D. [Figure 7] It is a schematic diagram showing an example of the gas-liquid mixing treatment apparatus 1A, (A) is a front view, and (B) is a partially enlarged cross-sectional view. [Figure 8] It is a schematic diagram showing an example of the gas-liquid mixing treatment apparatus 1B. [Figure 9] It is a view showing the schematic of the gas-liquid mixing treatment apparatus 1C. [Figure 10] It is a view showing the schematic of the gas-liquid mixing treatment apparatus 1D. [Figure 11] It is a view showing the schematic of the gas-liquid mixing treatment apparatus 1E. [Figure 12] It is a view schematically showing a method for measuring the amount of dissolved air.

Embodiments for Carrying out the Invention

[0018] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The liquid treatment apparatus of the present invention is an apparatus for mixing a fluid with a liquid to be treated or removing a gas contained in the liquid to be treated.

[0019] <The First Embodiment> FIG. 1 is a schematic diagram showing an example of the gas-liquid mixing treatment apparatus 1 and the liquid treatment apparatus 2 according to the first embodiment of the present invention. The liquid treatment apparatus 2 mainly includes a gas-liquid mixing treatment apparatus 1, a flow path 20, a gas suction portion 32, a pump 33, and valves 34 and 35. The liquid treatment apparatus 2 is mainly connected to a flow path 20A, a tank 31, a pressure adjustment portion 36, a liquid to be treated supply portion 37, a tank 38, and the like.

[0020] The gas-liquid mixing device 1 is installed in the flow path 20 of the liquid processing device 2. The flow path 20 includes pipes, hoses, fittings, etc., through which fluids (liquid, gas) flow. In addition to the gas-liquid mixing device 1, the flow path 20 is also equipped with a gas intake section 32, a pump 33, and valves 34 and 35. However, valves 34 and 35 are not essential in the liquid processing device 2.

[0021] Flow path 20 is connected to flow path 20A. Flow path 20A includes upstream sections 23a, 23b, 23c and downstream sections 23d, 23e, 23f. A tank 31, a pressure adjustment unit 36, a liquid to be treated supply unit 37, a tank 38, etc. are connected to flow path 20A. In this embodiment, the liquid to be treated flowing through flow paths 20 and 20A is either water, which is a liquid, or a liquid mixture of water and a gas (e.g., air, carbon dioxide).

[0022] Tank 31 is a container for storing the liquid to be treated, and is, for example, a bathtub. Tank 31 is provided with an outlet 31a. One end of the upstream section 23a is connected to the outlet 31a, and the other end is connected to the liquid treatment device 2 (in this case, valve 35) via the upstream section 23b.

[0023] A flow path switching section (not shown) may be provided between the upstream section 23a and the upstream section 23b. This flow path switching section can switch between connecting the upstream section 23b to the upstream section 23a or to the upstream section 23c. Alternatively, the upstream section 23c may be connected to the liquid to be treated supply section 37, and the flow path switching section may be connected to the upstream section 23c, thereby causing the liquid to be treated supplied by the liquid to be treated supply section 37 to flow into the liquid treatment apparatus 2 (in this case, the valve 35) via the upstream sections 23c and 23b.

[0024] Valve 35 is the inlet for the liquid to be treated in the liquid treatment apparatus 2. The upstream section 21a of the upstream path 21 (described in detail later) is connected to valve 35, and the liquid to be treated flowing through the upstream section 23b flows into the upstream section 21a via valve 35. If valve 35 is not available, the upstream section 21a and the upstream section 23b can be connected directly.

[0025] The gas intake section 32 is a component that mixes fluid with the liquid to be processed and is located upstream of the pump 33. The gas intake section 32 is, for example, an ejector. The gas intake section 32 has a supply port 32a for the liquid to be processed, a discharge port 32b for the liquid to be processed, and a gas intake port 32c. The liquid to be processed flows into the gas intake section 32 from the supply port 32a and flows out from the discharge port 32b after passing through a nozzle and suction chamber provided inside the gas intake section 32. As the liquid to be processed passes through the nozzle and diffuser, the pressure in the suction chamber decreases, and gas is drawn into the suction chamber from the intake port 32c, where the gas is mixed with the liquid to be processed.

[0026] Pump 33 is located downstream of the gas intake section 32. The upstream side of the flow path 20 to pump 33 is designated as the upstream path 21 (upstream section 21a and downstream section 21b), and the downstream side is designated as the downstream path 22 (upstream section 22a and downstream section 22b). Pump 33 discharges the liquid to be treated from the tank 31 to the upstream path 21, discharges the liquid to be treated from the gas intake section 32, and discharges the liquid to be treated from the downstream path 22 to the downstream section 23d of flow path 20A. Pump 33 can be a centrifugal pump (cascade pump, volute pump, etc.) or a positive displacement pump.

[0027] The gas-liquid mixing device 1 is located downstream of the pump 33. The gas-liquid mixing device 1 is pressurized to a pressure above atmospheric pressure (for example, 0.3 MPa or higher), and dissolves the fluid after the liquid to be processed and the mixed fluid have been mixed under a pressurized environment. A boundary layer exists between the liquid (liquid to be processed) and the gas within the gas-liquid mixing device 1. Due to the presence of this boundary layer, the gas is sufficiently dissolved within the gas-liquid mixing device 1, and undissolved gas is less likely to be discharged from the gas-liquid mixing device 1. In other words, by using the gas-liquid mixing device 1, even if the same amount of gas is supplied, the dissolution ratio can be increased, thereby increasing the efficiency of gas consumption and, as a result, minimizing the amount of gas consumed.

[0028] If the gas is discharged undissolved without using the gas-liquid mixing device 1, the gas dissolved in the liquid will cause the undissolved gas to grow, and as the undissolved gas grows, the amount of gas dissolved in the liquid will decrease. In contrast, in this embodiment, since the gas-liquid mixing device 1 is used, the undissolved gas is less likely to be discharged from the gas-liquid mixing device 1, and the gas dissolved in the liquid can be kept dissolved. The gas-liquid mixing device 1 will be described in detail later.

[0029] An upstream section 22a is connected to the downstream side of the gas-liquid mixing device 1, and a downstream section 22b is connected to the downstream side of the gas-liquid mixing device 1. A pressure gauge may be provided in either the upstream section 22a or the downstream section 22b. A valve 34 is provided on the downstream side of the gas-liquid mixing device 1 via the downstream section 22b. A downstream section 23d is connected to the valve 34. The liquid to be treated flowing through the downstream section 22b flows into the downstream section 23d via the valve 34. If there is no valve 34, the downstream section 22b and the downstream section 23d can be connected directly.

[0030] The downstream section 23d is connected to the downstream section 23e, and the pressure regulating section 36 is connected to the downstream section 23e. The pressure regulating section 36 is provided between the tank 31 and the valve 34. In this embodiment, the pressure regulating section 36 is provided on the side of the tank 31. The pressure regulating section 36 is a component that adjusts the pressure in the downstream sections 22b and 23d and 23e, and has a throttling mechanism that narrows the flow path diameter. For example, an orifice can be used for the pressure regulating section 36.

[0031] A flow path switching section (not shown) may be provided between the downstream section 23d and the downstream section 23e. This flow path switching section can switch between connecting the downstream section 23d to the downstream section 23e or to the downstream section 23f. Alternatively, a tank 38 may be connected to the downstream section 23f, and the liquid to be treated discharged from the gas-liquid mixing apparatus may be supplied to the tank 38 via the downstream sections 22b and 23d and 23f. In this case, the pressure of the liquid to be treated supplied to the tank 38 is adjusted using a valve 34. The tank 38 can be any container capable of storing the liquid to be treated. When supplying the liquid to be treated to the tank 38, the downstream section 23e, the pressure adjustment section 36, and the tank 31 are not used.

[0032] Next, the gas-liquid mixing apparatus 1 will be described using Figures 2 to 5. Figure 2 is a schematic diagram of the gas-liquid mixing apparatus 1, where (A) is a front view and (B) is a view taken along arrow A in (A). Figure 3 is a schematic cross-sectional view of the gas-liquid mixing apparatus 1. The gas-liquid mixing apparatus 1 mainly comprises a mixing unit 10, an inlet unit 14, and an outlet unit 15.

[0033] The mixing section 10 mainly comprises a cylindrical section 11 (corresponding to the first cylindrical section of the present invention), an upper plate 12, and a lower plate 13. The upper plate 12 covers the upper end of the cylindrical section 11, and the lower plate 13 covers the lower end of the cylindrical section 11. The liquid to be processed is stored inside the mixing section 10.

[0034] The cylindrical portion 11 mainly comprises a cylindrical portion 11a, a cylindrical portion 11b that fixes the cylindrical portion 11a to the upper plate 12, and a cylindrical portion 11c that fixes the cylindrical portion 11a to the lower plate 13. The cylindrical portion 11b and the upper plate 12, and the cylindrical portion 11c and the lower plate 13 are fixed by fixing members 19. The fixing members 19 are, for example, bolts and nuts. Note that the form of the cylindrical portion 11 is not limited to this, and for example, the cylindrical portions 11b and 11c are not essential.

[0035] The central axis ax1 of the cylindrical portion 11 (corresponding to the first central axis of the present invention) is inclined with respect to the vertical direction. Hereinafter, the direction along the central axis ax1 will be referred to as the x direction (corresponding to the first direction of the present invention), and the horizontal direction as the y direction. Furthermore, the direction perpendicular to the x and y directions will be referred to as the z direction (corresponding to the second direction of the present invention).

[0036] In this embodiment, the cylindrical portion 11a is cylindrical in shape, but the shape of the cylindrical portion 11a is not limited to this, and it can be any shape that is cylindrical. For example, a rectangular tube may be used for the cylindrical portion 11a. The rectangular tube is not limited to having a rectangular cross-section, but may have a hexagonal or octagonal cross-section. Furthermore, the cylindrical portion 11a may be bent or have steps.

[0037] The central axis ax1 of the cylindrical portion 11 is inclined with respect to the horizontal and vertical directions, and the liquid surface L of the liquid being treated, aligned horizontally, is inclined with respect to the z direction. Therefore, the area of ​​the liquid surface L can be made larger compared to the case where the central axis ax1 is aligned vertically.

[0038] The upper plate 12 has a hole 12a (corresponding to the first hole of the present invention), and the lower plate 13 has a hole 13a (corresponding to the second hole of the present invention). Hole 12a is part of the inlet 14, and hole 13a is part of the outlet 15.

[0039] When cut by a plane parallel to the yz plane, it is desirable that the area of ​​the cylindrical portion 11 be approximately 7 to 15 times the area of ​​the hole 12a. This allows a sufficient amount of the liquid to be treated to be stored in the mixing portion 10.

[0040] The inlet section 14 is provided on the upper plate 12 and allows the liquid to be treated to flow into the interior (space S1) of the mixing section 10. The inlet section 14 mainly has a hole 12a, a direction changing section 14a, and an injection hole 14b. The inlet section 14 is provided with inlet pipes 20a and 20b, which are part of the flow path 20. The inlet pipe 20b is fitted into the hole 12a from the outside of the mixing section 10.

[0041] The direction changing section 14a is provided inside the mixing section 10 so as to cover the hole 12a. The direction changing section 14a mainly has a cylindrical section 14d (corresponding to the second cylindrical section of the present invention) and an end section 14c. The cylindrical section 14d is a cylindrical member with one end in contact with the upper plate 12. The end section 14c is a member that covers the end of the cylindrical section 14d that is not in contact with the upper plate 12. Therefore, a space S2 is formed inside the direction changing section 14a.

[0042] The central axis ax2 of the cylindrical portion 14d (corresponding to the second central axis in this embodiment) is aligned in the x-direction, similar to the central axis ax1. In this embodiment, the central axes ax1 and ax2 coincide.

[0043] The injection holes 14b are provided in the direction changing section 14a. Multiple injection holes 14b are also provided in the cylindrical section 14d. The size of each injection hole 14b is smaller than the size of the holes 12a. Furthermore, the sum of the areas of the multiple injection holes 14b is less than or equal to the area of ​​the holes 12a. The cylindrical section 14d may also be provided with drain holes 14n to remove the liquid being treated that has accumulated inside the direction changing section 14a.

[0044] Figure 4 is a view from arrow B in Figure 3. Specifically, the injection holes 14b are provided in an area visible when the direction changing section 14a is viewed from the vertically downward side. In this embodiment, the injection holes 14b are provided in half of the area on the lower side (-z side, or vertically downward side) of the side surface of the cylindrical section 14d. The injection holes 14b are circular or elliptical in shape and are provided in multiple locations along the x direction. Furthermore, the injection holes 14b are arranged symmetrically across the xz plane.

[0045] Figure 5 is a cross-sectional view of the CC section of Figures 3 and 4, showing the direction-changing section 14a (cylindrical section 14d) cut by a plane perpendicular to the x-direction (a plane parallel to the yz-plane). The angle between line l1 (corresponding to the first line of the present invention), which is along the z-direction and passes through the central axis ax2, and line l2 (corresponding to the second line of the present invention), which connects the central axis ax2 and the center of the injection hole 14b, is approximately 45 degrees. The injection holes 14b are arranged symmetrically across line l1 (xz-plane), and the angle between the two lines l2 is approximately 90 degrees.

[0046] Furthermore, it is desirable that the area of ​​the cylindrical portion 14d be approximately 1 to 4 times the area of ​​the hole 12a. Also, it is desirable that the total area of ​​the injection holes 14b be approximately 0.2 to 0.5 times the area of ​​the hole 12a. This makes it possible to shorten the residence time of the liquid to be treated in the mixing section 10. For example, if the mixing section 10 (central axis ax1) is not inclined with respect to the vertical direction, the liquid to be treated is allowed to remain inside the mixing section 10 for approximately 5 seconds or more and approximately 24 seconds or less to separate the gas that did not dissolve in the liquid to be treated (excess bubbles) from the liquid to be treated. In contrast, if the mixing section 10 is inclined with respect to the vertical direction and the direction changing section 14a and injection holes 14b are used, the mixing section 10 can be made smaller, and even if the residence time of the liquid to be treated in the mixing section 10 is shortened to approximately 2.5 seconds or more and approximately 10 seconds or less, excess bubbles can still be separated from the liquid to be treated.

[0047] Although the cylindrical portion 14d is cylindrical in shape, its shape is not limited to this. For example, it may be a hollow frustoconical shape. Also, the area of ​​the cylindrical portion 14d may be less than or equal to the area of ​​the hole 12a.

[0048] The outlet section 15 is provided on the lower plate 13 and discharges the liquid to be treated from the mixing section 10. The outlet section 15 has a hole 13a, and outlet pipes 20c and 20d, which are part of the flow path 20, are provided in the hole 13a. The outlet pipe 20d is fitted into the hole 13a from the outside of the mixing section 10.

[0049] Next, the operation of the gas-liquid mixing apparatus 1 and the liquid apparatus 2 will be described. As shown in Figure 1, when the pump 33 is driven, the liquid to be processed flows from the tank 31 to the liquid apparatus 2 via the upstream sections 23a and 23b. In the liquid apparatus 2, the liquid to be processed first flows into the gas intake section 32 via the upstream section 21a. When the pump 33 is driven stably and the flow rate exceeds a certain level, negative pressure is generated as the liquid to be processed passes through the gas intake section 32, causing gas to mix with the liquid, and a liquid to be processed is produced in which fine bubbles are mixed with water.

[0050] The liquid to be treated, which is a mixture of water and fine bubbles (gas), is guided by the pump 33 to the gas-liquid mixing treatment device 1 via the downstream section 21b. The flow of the liquid to be treated in the gas-liquid mixing treatment device 1 will be explained using Figure 3. The liquid to be treated flows into the space S2 inside the direction change section 14a via the inlet pipes 20a and 20b.

[0051] Since the total area of ​​the injection holes 14b is less than or equal to the area of ​​the holes 12a, the liquid to be treated that flows into space S2 remains in space S2 for a while before flowing out from the injection holes 14b into space S1 inside the mixing section 10. Also, because the area of ​​the injection holes 14b is smaller than the area of ​​the holes 12a, the flow velocity of the liquid to be treated in the injection holes 14b is faster than the flow velocity of the liquid to be treated in the holes 12a.

[0052] Since the injection holes 14b are located in the lower half of the cylindrical portion 14d, the liquid to be treated injected from the injection holes 14b is incident at an oblique angle to the liquid surface L. The angle between lines l1 and l2 is approximately 45 degrees, so the angle of incidence of the liquid to be treated injected from the injection holes 14b onto the liquid surface L is approximately 45 degrees. By tilting the liquid surface L with respect to the z direction, the surface area of ​​the liquid increases, and the oblique incidence of the liquid to be treated on the liquid surface L generates turbulent bubble vortices on the liquid surface, allowing for efficient mixing of gas and liquid in the liquid to be treated. As a result, the dissolution rate of gas into liquid increases, and the dissolution of gas into liquid is promoted. Furthermore, since the central axis ax1 of the cylindrical portion 11 is tilted with respect to the vertical (or horizontal) direction, the cylindrical portion 11 can be made smaller compared to a configuration in which the central axis ax1 of the cylindrical portion 11 is aligned with the vertical direction.

[0053] The liquid to be treated, upon entering the liquid surface L, is temporarily stored in space S1. At this time, gases that did not dissolve in the liquid to be treated (excess bubbles) accumulate at the top of space S1. The liquid to be treated stored in space S1 flows out of space S1 through hole 13a.

[0054] Because the central axis ax1 is inclined with respect to the horizontal or vertical direction, it is possible to offset the horizontal position of the liquid surface L from the horizontal position of the holes 13a while ensuring a retention space for the liquid to be treated in the mixing section 10. As a result, excess bubbles are less likely to flow out from the holes 13a. The less excess bubbles that flow out, the finer the bubbles in the liquid to be treated become.

[0055] Parts of the flow paths 20 and 20A (upstream sections 23a, 23b, 21a, downstream section 21b, upstream section 22a, downstream sections 22b, 23d, and downstream section 23e) constitute a fluid circulation circuit in which the liquid to be treated flows out of the tank 31, flows through the liquid treatment device 2, and then returns to the tank 31. The mixed liquid treated in the gas intake section 32 is pressurized and dissolved in the gas-liquid mixing device 1, returned to atmospheric pressure, and then returned to the tank 31, where it flows again through the flow path 20 and is treated in the gas intake section 32. When the liquid treatment device 2 is a fluid circulation circuit, the same liquid to be treated can be treated multiple times in the gas intake section 32 and the gas-liquid mixing device 1, and the mixed fluid can be efficiently mixed with the liquid to be treated.

[0056] Furthermore, parts of the flow paths 20 and 20A (for example, the upstream sections 23c, 23b, 21a, the downstream section 21b, the upstream section 22a, the downstream sections 22b, 23d, and the downstream section 23f) are so-called one-pass flow paths in which the liquid to be treated flows through the liquid treatment device 2 only once (leading the liquid to be treated supplied from the liquid treatment supply unit 37 to the tank 38). Even in the case of one-pass flow paths (not fluid circulation circuits), the mixing efficiency is improved by having the liquid to be treated pass through the gas-liquid mixing treatment device 1.

[0057] Table 1 shows the relationship between the presence or absence of the direction change section 14a and the injection hole 14b and the dissolution ratio. The dissolution ratio is an indicator of the degree of solubility of the gas in the liquid being treated (details will be provided later). Furthermore, Table 1 shows the results obtained from experiments conducted with the pressure of the gas-liquid mixing treatment device 1 set to 0.4 MPa. [Table 1]

[0058] Example 1 in Table 1 shows the dissolution ratio in a configuration having a direction change section 14a and an injection hole 14b, i.e., in the gas-liquid mixing apparatus 1. Comparative Example 1 in Table 1 shows a configuration in which the direction change section 14a and injection hole 14b are omitted from the gas-liquid mixing apparatus 1. By comparing Example 1 and Comparative Example 1, it was found that the dissolution ratio is significantly increased by using the direction change section 14a and injection hole 14b.

[0059] Comparative Example 2 in Table 1 shows the result of reducing the size of the hole 12a and making the flow velocity through the hole 12a faster than the flow velocity through the injection hole 14b in Example 1. Comparing Example 1 and Comparative Example 2, it was found that the effect of improving the dissolution ratio by using the direction change section 14a and injection hole 14b was greater than the effect of improving the dissolution ratio by increasing the flow velocity.

[0060] Here, we will explain the dissolution ratio. Figure 12 is a schematic diagram showing the method for measuring the amount of dissolved air. The dissolved air amount measuring device 100 mainly consists of a gas-liquid mixing treatment device 1, flow paths 20, 102, and 106, an air storage cylinder 103, a water storage tank 104, and a pressure release valve 105. For example, the measuring device 100 measures the amount of air dissolved in 1 L of pressurized liquid to be treated, as follows.

[0061] A flow path 102 is connected to the downstream flow path 20 of the gas-liquid mixing device 1, which is installed in the flow path 20 of the liquid processing device 2. First, the liquid to be processed flowing through flow path 20 is pressurized and dissolved in the gas-liquid mixing device 1, and large undissolved bubbles are separated and removed. The liquid to be processed from which the undissolved bubbles have been separated and removed is then flowed into flow path 102. Next, the liquid to be processed flowing through flow path 102 is depressurized to atmospheric pressure by the pressure release valve 105 and released into the air storage cylinder 103. In the air storage cylinder 103, bubbles are separated from the liquid to be processed to become fine bubbles, which float and accumulate at the top of the air storage cylinder 103, while the liquid to be processed accumulates in the water storage tank 104 connected by flow path 106. The pressure release valve 105 adjusts the discharge rate (velocity) of the liquid to be processed so that bubbles do not flow into the water storage tank 104.

[0062] When 1 liter of the liquid to be treated has accumulated in the water tank 104, the amount of air in the air storage cylinder 103 is measured. The amount of air in the air storage cylinder 103 represents the amount of air precipitated from 1 liter of the liquid to be treated, i.e., the amount of dissolved air. These measurements are performed using scales provided on the transparent air storage cylinder 103 and the water tank 104.

[0063] As shown in equation (1), the measured value is corrected based on the ambient temperature at the time the amount of air in the air reservoir 103 was measured (when the measured amount of air was obtained), and the amount of dissolved air is determined. Then, as shown in equation (2), the dissolution ratio is calculated using the amount of dissolved air and the saturated dissolution amount at the temperature of the liquid being treated (in this case, water temperature) at the time the measured value was obtained. Note that the saturated dissolution amount is a fixed value depending on the type of liquid and gas, temperature, and pressure.

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[0064] According to this embodiment, by using the direction change section 14a and the injection hole 14b, the gas can be efficiently mixed with the liquid.

[0065] Furthermore, according to this embodiment, the direction changing section 14a has a cylindrical section 14d, and by providing injection holes 14b in the lower half of the side surface of the cylindrical section 14d, a structure can be created in which the liquid to be treated, injected from the injection holes 14b, is easily incident on the liquid surface L at an oblique angle.

[0066] In this embodiment, air was supplied to the gas intake section 32 as the mixed fluid and dissolved in water, but the gas is not limited to air. Also, in this embodiment, the liquid used for processing was water, but the liquid is not limited to water. For example, gases such as hydrogen and oxygen may be supplied to the gas intake section 32 and dissolved in the liquid, or the air contained in the liquid may be replaced with carbon dioxide, nitrogen, etc.

[0067] Furthermore, the liquid processing apparatus 2 shown in Figure 1 is applicable when approximately 3% to approximately 10% of the processing volume of oxygen, nitrogen, carbon dioxide, etc. is introduced from the gas intake section 32. However, if a larger amount of gas is to be introduced, this can be handled by introducing pressurized gas into the upstream section 22a.

[0068] <Variations of injection nozzles> In this embodiment, six injection holes 14b were provided in the direction change section 14a, but the position, number, and size of the injection holes are not limited to this.

[0069] Figure 6 shows an example of the shape of the injection holes according to the modified form. Figure 6(A) is a schematic diagram of the inlet section 14A in which twelve round injection holes 14b are provided in the direction changing section 14a, Figure 6(B) is a schematic diagram of the inlet section 14B in which two elongated injection holes 14e are provided in the direction changing section 14a, and Figure 6(C) is a schematic diagram of the inlet section 14C in which two elongated injection holes 14f are provided in the direction changing section 14a. Figure 6(D) is a schematic diagram of the inlet section 14D in which six round injection holes 14g are provided in the direction changing section 14a.

[0070] In Figures 6(A) to (D), (a) is a view of the cylindrical portion 14d from the -z direction (end portion 14c is not shown), and (b) shows the cylindrical portion 14d cut by a plane parallel to the yz plane. In Figures 6(A) to (C), the injection holes 14b, 14e, and 14f are arranged symmetrically with respect to line l1, and the angle between the two lines l2 is approximately 90 degrees. In Figure 6(D), the injection hole 14g is arranged symmetrically with respect to line l1, and the angle between the two lines l2 is approximately 120 degrees. Line l2 is the line connecting the central axis ax2 and the centers of the injection holes 14b, 14e, 14f, and 14g. In all cases of the inlet portions 14A to 14D, the diameter of the hole 12a is 23 mm, similar to the inlet portion 14.

[0071] Table 2 shows the dissolution ratio when the position, number, and size of the injection holes are changed. Example 1 is the result for the inlet 14 (6 injection holes 14b) shown in Figures 3-5, Example 2 is the result for the inlet 14A (12 injection holes 14b), Example 3 is the result for the inlet 14B (2 injection holes 14e), Example 4 is the result for the inlet 14C (2 injection holes 14f), and Example 5 is the result for the inlet 14D (6 injection holes 14g). The pressure inside the mixing section 10 at this time is 0.4 MPa. [Table 2]

[0072] As shown in Examples 1-4, when the angle between the two lines l2 was approximately 90 degrees, an excellent dissolution ratio was obtained regardless of the flow velocity and the number and shape of the injection holes. In contrast, when the angle between the two lines l2 was approximately 120 degrees, although the dissolution ratio was higher than in Comparative Example 1 (see Table 1), it was lower than when the angle between the two lines l2 was approximately 90 degrees. From the above, it was found that by arranging the injection holes symmetrically on either side of line l1 and setting the angle between the two lines l2 to approximately 90 degrees, the gas can be dissolved in the liquid more efficiently.

[0073] In Examples 1-4, the injection holes were arranged symmetrically across line l1, but the arrangement of the injection holes is not limited to this. For example, the injection holes do not have to be arranged symmetrically across line l1. Also, for example, the injection holes may be arranged only on the +y side of line l1. In this case, multiple injection holes may be arranged in a line along the x direction. Furthermore, the number of injection holes is not limited to multiples; for example, only one injection hole 14e, 14f may be formed in the cylindrical part. However, by arranging the injection holes symmetrically across line l1, the amount of liquid to be treated that is incident on the liquid surface L at a desired angle increases, thereby enabling efficient dissolution of gas in the liquid.

[0074] <Second Embodiment> In the first embodiment of the present invention, the hole 13a was located on the central axis ax1, but the position of the hole 13a is not limited to this. Hereinafter, a gas-liquid mixing apparatus 1A according to the second embodiment of the present invention will be described. Note that parts identical to those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted.

[0075] Figure 7 is a schematic diagram showing an example of a gas-liquid mixing apparatus 1A, where (A) is a front view and (B) is a partially enlarged cross-sectional view. The gas-liquid mixing apparatus 1A is installed in the liquid apparatus 2, similar to the gas-liquid mixing apparatus 1.

[0076] The gas-liquid mixing apparatus 1A mainly comprises a mixing section 10A, an inlet section 14, and an outlet section 15. The mixing section 10A mainly comprises a cylindrical section 11, an upper plate 12, and a lower plate 13A.

[0077] The lower plate 13A has holes 13a that are included in the outlet section 15. The central axis ax3 of the holes 13a is formed below the central axis ax1. Therefore, the height from the outlet section 15 to the liquid level L can be increased. As a result, excess bubbles are less likely to flow out of the outlet section 15.

[0078] <Third Embodiment> In the first embodiment of the present invention, the hole 12a was located on the central axis ax1, but the position of the hole 12a is not limited to this. Hereinafter, a gas-liquid mixing apparatus 1B according to the third embodiment of the present invention will be described. Note that parts identical to those in the first and second embodiments are denoted by the same reference numerals and their descriptions are omitted.

[0079] Figure 8 is a schematic diagram showing an example of a gas-liquid mixing apparatus 1B. Like the gas-liquid mixing apparatus 1, the gas-liquid mixing apparatus 1B is installed in the liquid apparatus 2.

[0080] The gas-liquid mixing apparatus 1A mainly comprises a mixing section 10B, an inlet section 14, and an outlet section 15. The mixing section 10B mainly comprises a cylindrical section 11, an upper plate 12A, and a lower plate 13A.

[0081] The upper plate 12A has holes 12a formed within the inlet 14. The central axis ax2 of the holes 12a is formed below the central axis ax1. Therefore, the distance from the injection holes 14b to the liquid surface L can be reduced. As a result, the liquid to be treated comes into contact with the liquid surface L, causing the surface L to become rougher, and gas can be efficiently mixed with the liquid.

[0082] <Fourth Embodiment> In the first embodiment of the present invention, the inlet 14 has a cylindrical tubular portion 14d and a planar end portion 14c, but the shape of the inlet is not limited thereto. Parts identical to those in the first to third embodiments are denoted by the same reference numerals and their descriptions are omitted.

[0083] Figure 9 is a schematic diagram of the gas-liquid mixing apparatus 1C. The gas-liquid mixing apparatus 1C mainly comprises a mixing section 10C, an inlet section 14E, and an outlet section 15. The mixing section 10C mainly comprises a cylindrical section 11A (corresponding to the first cylindrical section of the present invention), an upper plate 12, and a lower plate 13. The cylindrical section 11A mainly comprises a cylindrical section 11a, a cylindrical section 11d that fixes the cylindrical section 11a to the upper plate 12, and a cylindrical section 11e that fixes the cylindrical section 11a to the lower plate 13. In this case, the cylindrical section 11A can be formed using general flange piping.

[0084] The inlet section 14E has a direction-changing section 14h in which an injection hole 14b is formed. The direction-changing section 14h mainly has a cylindrical section 14i (corresponding to the second cylindrical section of the present invention) and an end section 14j. The cylindrical section 14i is a cylindrical member with one end in contact with the upper plate 12. The end section 14j is a member that covers the end of the cylindrical section 14i that is not in contact with the upper plate 12. For example, at least one of the cylindrical section 14i and the end section 14j may include a curved surface, and the cylindrical section 14i and the end section 14j may be connected by a curved surface. Alternatively, the entire end section 14j may be a curved surface.

[0085] <Fifth Embodiment> In the first embodiment of the present invention, the inlet 14 has a cylindrical tubular portion 14d, but the shape of the inlet is not limited to this. Parts identical to those in the first to fourth embodiments are denoted by the same reference numerals and their descriptions are omitted.

[0086] Figure 10 is a schematic diagram of a modified gas-liquid mixing apparatus 1D. The gas-liquid mixing apparatus 1D mainly comprises a mixing section 10C, an inlet section 14F, and an outlet section 15.

[0087] The inlet section 14F has a direction-changing section 14k in which injection holes 14b are formed. The direction-changing section 14k mainly has a cylindrical section 14l (corresponding to the second cylindrical section of the present invention) and an end section 14m. The cylindrical section 14l is a rectangular tube-shaped member with one end in contact with the upper plate 12. The end section 14m is a member that covers the end of the cylindrical section 14i that is not in contact with the upper plate 12. Note that the cylindrical section 14l is not limited to a rectangular tube with a rectangular cross-section, but may be a rectangular tube with a hexagonal or octagonal cross-section. Furthermore, the cylindrical section 14l is not limited to a rectangular tube shape, but may be, for example, a hollow truncated pyramidal shape.

[0088] <Other> In addition, in the inlet sections 14A to 14F, the direction-changing sections 14a, 14h, and 14k have cylindrical sections 14d, 14i, and 14l, and the flow area (cross-sectional area) of the cylindrical sections 14d, 14i, and 14l is larger than the flow area (hole diameter) of the hole 12a, but the flow area of ​​the cylindrical sections 14d, 14i, and 14l may be less than or equal to the flow area of ​​the hole 12a.

[0089] Furthermore, although the direction-changing sections 14a, 14h, and 14k have cylindrical sections 14d, 14i, and 14l, the cylindrical sections are not essential, and the shape of the direction-changing sections is not limited to these. For example, the direction-changing section may be a hemispherical shape with a hollow interior, or a conical or pyramidal shape with a hollow interior. Regardless of the shape of the direction-changing section, it is sufficient that the injection holes are provided in an area that can be seen when the direction-changing section is viewed from the vertically downward side. Even if the direction-changing section has such shapes, it is possible to provide injection holes at a position where the angle between the central axis ax2 and line l2 is approximately 45 degrees when cut by a plane parallel to the yz plane, similar to the injection hole 14b.

[0090] The liquid processing apparatus 2 according to the above embodiment may also include a control unit. The control unit includes, as hardware resources, a computing device such as a CPU (Central Processing Unit) for executing information processing, and a storage device such as RAM (Random Access Memory) or ROM (Read Only Memory). The liquid processing apparatus 2 may also have a liquid level acquisition unit that acquires the height of the liquid level L of the liquid to be processed in the cylindrical portion 11A. The liquid level acquisition unit includes, for example, a sensor or imaging unit that acquires the height of the liquid level L. When an imaging unit is used, the cylindrical portion 11A is formed using a transparent material so as to acquire the position of the liquid level L. When a sensor such as an ultrasonic sensor is used, for example, the ultrasonic sensor is attached to the outside of the cylindrical portion 11A so that the element faces the liquid level L. The control unit adjusts the flow rate of gas in the gas intake portion 32 according to the position of the liquid level L.

[0091] When the gas is not dissolved in the liquid, the liquid level L is low, and when the gas dissolves in the liquid, the liquid level L rises. Therefore, when the liquid level L is low, the amount of gas introduced into the gas intake section 32 is reduced, and as the liquid level L rises, the amount of gas introduced into the gas intake section 32 is increased. This allows the amount of gas introduced to be adjusted according to the degree of gas solubility, enabling efficient mixing of the gas with the liquid. Furthermore, in a configuration where the cylindrical sections 11 and 11A are transparent and the inside of the cylindrical sections 11 and 11A is observed using an imaging device, it is possible to monitor whether undissolved gas is flowing at the liquid outlet, thereby reducing the amount of excess gas introduced and saving gas.

[0092] Furthermore, if a sensor such as an ultrasonic sensor is used as the liquid level acquisition unit, the transparent cylindrical part 11A is not mandatory, and a non-transparent cylindrical part 11 may be used instead. Also, the sensor for the liquid level acquisition unit may be installed on the outside of the cylindrical part 11, or on the upper plate 12 or lower plate 13. For example, a hole (for example, a hole that penetrates in the thickness direction, such as hole 13b (see Figure 11)) may be made in the upper plate 12 or lower plate 13, the sensor may be inserted into the hole so that the element faces the liquid level L, and the hole may be sealed with a sealing material.

[0093] Figure 11 is a schematic diagram of a gas-liquid mixing apparatus 1E equipped with a liquid level height acquisition unit having a sensor for acquiring the height of the liquid level L. The gas-liquid mixing apparatus 1E mainly comprises a mixing unit 10D, an inlet unit 14 (not shown), an outlet unit 15, and a liquid level height acquisition unit 40.

[0094] The mixing section 10D mainly consists of a cylindrical section 11, an upper plate 12B, and a lower plate 13B. The upper plate 12B has holes (not shown), and the lower plate 13B has holes 13b.

[0095] The liquid level acquisition unit 40 has a cylindrical portion 41 and connecting portions 42 and 43. Both ends of the connecting portion 42 are provided on the cylindrical portion 41 and the upper plate 12B, respectively, and one end of the connecting portion 42 is fitted into a hole (not shown) in the upper plate 12B from the outside of the mixing portion 10D. Both ends of the connecting portion 43 are provided on the cylindrical portion 41 and the lower plate 13B, respectively, and one end of the connecting portion 43 is fitted into a hole 13b from the outside of the mixing portion 10D. As a result, the space S1 and the inside of the cylindrical portion 41 are in communication.

[0096] The cylindrical portion 41 is made of a transparent material. Since the space S1 and the inside of the cylindrical portion 41 are in communication, the liquid to be treated flows into the cylindrical portion 41, and the liquid level in the cylindrical portion 41 is the same as the liquid level in the cylindrical portion 11.

[0097] The cylindrical portion 41 is equipped with a plurality of sensors 44, 45, 46, and 47. The sensors 44, 45, 46, and 47 are, for example, optical liquid level sensors and include a light-emitting part (e.g., an LED) that emits infrared light and a light-receiving part. For example, light emitted from a light source is guided to the light-receiving part through the inside of the transparent cylindrical portion 41. When there is no liquid, infrared light reaches the light-receiving part, and when the inside of the cylindrical portion 41 is filled with the liquid to be processed, infrared light can no longer reach the light-receiving part, thereby detecting the liquid level. The plurality of sensors 44, 45, 46, and 47 can detect the height of the liquid level in the cylindrical portion 41, that is, the height of the liquid level in the cylindrical portion 11.

[0098] Furthermore, sensors 44, 45, 46, and 47 are not limited to optical liquid level sensors; for example, liquid level sensors using millimeter waves or ultrasound may be used. Also, the number and position of sensors 44, 45, 46, and 47 are not limited to the illustrated configuration. In addition, the entire cylindrical portion 41 does not have to be transparent; at least a part of the cylindrical portion 41, for example, the portion that overlaps with the light-emitting and light-receiving portions of sensors 44, 45, 46, and 47, must be transparent. Alternatively, the cylindrical portion 41 may not be transparent, and holes may be formed in the portion that overlaps with the light-emitting and light-receiving portions.

[0099] While embodiments of this invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments, and design modifications and the like are also included within the scope of the gist of this invention.

[0100] Furthermore, "approximately" is a concept that includes not only cases where things are strictly identical, but also errors or modifications that do not cause a loss of identity. For example, "approximately orthogonal" is a concept that is not limited to cases where things are strictly orthogonal, but also includes cases where they can be considered identical to orthogonal. Also, for example, when simply using terms such as orthogonal, parallel, or coincidence, it should include not only cases where things are strictly orthogonal, parallel, or coincidence, but also cases where things are approximately parallel, approximately orthogonal, or approximately coincidence.

[0101] Furthermore, "neighborhood" means a region that includes a certain range (which can be arbitrarily defined) near a reference point. For example, when we say "end neighborhood," it refers to a region that is near an edge, and it is a concept that indicates whether or not the edge is included. [Explanation of Symbols]

[0102] 1, 1A, 1B, 1C, 1D, 1E: Gas-liquid mixing apparatus 2: Liquid treatment equipment 10, 10A, 10B, 10C, 10D: Mixing section 11, 11A, 11a, 11b, 11c, 11d, 11e: Cylindrical part 12, 12A, 12B: Upper plate 13, 13A, 13B: Lower plate 12a, 13a, 13b: Hole 14, 14A, 14B, 14C, 14D, 14E, 14F: Inflow section 14a, 14h, 14k: Direction change section 14b, 14e, 14f, 14g: Injection hole 14c, 14j, 14m: End 14d, 14i, 14l: Cylindrical part 14n: Drain hole 15: Outlet 19: Fixing member 20, 20A: Flow path 20a, 20b: Inflow pipe 20c, 20d: Outflow pipe 21: Outflow route 22: Reflux pathway 21a, 22a, 23a, 23b, 23c: Upstream part 21b, 22b, 23d, 23e, 23f: downstream 31: Tank 31a: Outlet 32: Gas intake section 32a: Supply port 32b: Outlet 32c: Inlet 33: Pump 34, 35: Valve 36: Pressure adjustment section 37: Processing liquid supply unit 38: Tank 40: Liquid level acquisition unit 41: Cylindrical part 42, 43: Connection part 44, 45, 46, 47: Sensors 100: Measuring device 102: Flow channel 103: Air storage cylinder 104: Water storage tank 105: Pressure relief valve 106: Flow channel

Claims

1. A mixing section comprising a first cylindrical portion, an upper plate covering the upper end of the first cylindrical portion, and a lower plate covering the lower end of the first cylindrical portion, wherein a liquid to be processed, which is a mixture of liquid and gas, is stored. The upper plate is provided with an inlet for introducing the liquid to be processed into the mixing section, The lower plate is provided with an outlet section for discharging the liquid to be treated from the mixing section, Equipped with, The first central axis, which is the central axis of the first cylindrical portion, is inclined with respect to the vertical direction. The inlet section has a first hole provided in the upper plate, a hollow direction-changing section provided inside the mixing section so as to cover the first hole, and an injection hole provided in the direction-changing section. The area of ​​the injection hole is smaller than the area of ​​the first hole. The injection holes are located in an area that can be seen when the direction-changing section is viewed from the vertically downward side. A gas-liquid mixing apparatus characterized by the following:

2. The direction changing portion has a second cylindrical portion with one end in contact with the upper plate, and an end portion that covers the end of the second cylindrical portion that is not in contact with the upper plate. The second central axis, which is the central axis of the second cylindrical portion, is aligned with the first direction, which is the extending direction of the first central axis. The injection holes are provided in the lower half of the side surface of the second cylindrical portion. The gas-liquid mixing apparatus according to feature 1.

3. When the direction-changing portion is cut by a plane perpendicular to the first direction, the angle between the first line, which is a line that lies along the second direction perpendicular to the first direction and the horizontal direction and passes through the second central axis, and the second line, which is a line connecting the second central axis and the center of the injection hole, is approximately 45 degrees. The gas-liquid mixing apparatus according to feature 2.

4. The second cylindrical portion is provided with a plurality of injection holes, The total area of ​​the injection holes is less than or equal to the area of ​​the first hole. When the direction-changing portion is cut by a plane perpendicular to the first direction, the second line is positioned symmetrically with respect to the first line. The gas-liquid mixing apparatus according to feature 3.

5. The center of the first hole is located below the first central axis. A gas-liquid mixing apparatus according to any one of claims 2 to 4.

6. The outflow section has a second hole formed in the lower plate, The center of the second hole is located below the first central axis. A gas-liquid mixing apparatus according to any one of claims 1 to 5.

7. A gas-liquid mixing apparatus according to any one of claims 1 to 6, A flow path through which the liquid to be treated flows, the flow path in which the gas-liquid mixing apparatus is provided, A pump provided on the upstream side of the gas-liquid mixing device in the flow path, A gas intake section is provided on the upstream side of the flow path of the pump and mixes gas with the liquid to be processed, Equipped with, The pump causes the liquid to be processed to flow into the gas intake section, and the liquid that has passed through the gas intake section to flow into the gas-liquid mixing apparatus. A liquid processing apparatus characterized by the following:

8. A liquid level height acquisition unit that acquires the height of the liquid level of the liquid to be processed in the first cylindrical portion, A control unit adjusts the gas flow rate in the gas intake unit based on the results obtained by the liquid level acquisition unit, The liquid processing apparatus according to claim 7, characterized by comprising:

9. The first cylindrical portion is formed using a transparent material. The liquid level acquisition unit includes an imaging unit that acquires an image of the inside of the first cylindrical portion. The liquid processing apparatus according to claim 8.

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