Gas dissolution device and gas dissolution system

Abstract

To provide a gas dissolution device in which an optimum structure can be selected according to a degree of solubility of gas into liquid.SOLUTION: A gas dissolution device 100 includes a gas-liquid mixing device 10, bubble generation means 30, and bubble dissolution means 40. The gas-liquid mixing device 10 mixes gas and liquid to generate gas-liquid mixture. The bubble generation means generates bubbles in the gas-liquid mixture. The bubble dissolution means 40 dissolves the bubbles into the liquid. The bubble dissolution means 40 can be detached. The bubble dissolution means 40 is arranged outside the gas-liquid mixing device 10 and is a separate body from the gas-liquid mixing device 10.SELECTED DRAWING: Figure 2A

Description

[Technical field]

[0001] The present invention relates to a gas dissolving device.The present invention also relates to a gas dissolving system. [Background technology]

[0002] 2. Description of the Related Art Conventionally, gas dissolvers that dissolve gas bubbles in liquid are known.

[0003] Patent Document 1 discloses a gas dissolver comprising a gas-liquid mixing section which swirls a gas-containing fluid to efficiently mix the gas and liquid to obtain a gas-liquid mixed fluid, a gas-liquid mixed fluid outlet which generates tiny gas bubbles by spraying the gas-liquid mixed fluid, and a gas dissolution flow path which dissolves the gas bubbles, the gas dissolution flow path being characterized in that it has a spiral structure, and a water flow swirling means composed of an inner peripheral part of an outer casing provided on the outer periphery of the gas-liquid mixing section, a spirally formed flow straightener provided within the outer casing, and the outer peripheral part of an inner casing which defines the outer periphery of the gas-liquid mixing section generates a swirling flow having centrifugal force in the fluid containing tiny gas bubbles, providing more resistance than a cylindrical flow path and increasing the dissolution efficiency. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5218948 Summary of the Invention [Problem to be solved by the invention]

[0005] In the gas dissolver of Patent Document 1, the outer casing, the bottom plate, and the lid are fixed to each other, and the gas dissolution passage is provided inside the outer casing. Therefore, the structure of the gas dissolution passage, such as the length of the gas dissolution passage, cannot be changed.

[0006] An object of the present invention is to provide a gas dissolving device capable of selecting an optimum structure depending on the solubility of a gas in a liquid, and a gas dissolving system including the gas dissolving device. [Means for solving the problem]

[0007] The present application provides the following aspects of the invention. (Section 1) a gas-liquid mixer that mixes the gas and the liquid to generate a gas-liquid mixed liquid; A bubble generating means for generating bubbles in the gas-liquid mixture; a removable bubble dissolving means that is disposed outside the gas-liquid mixer and separate from the gas-liquid mixer, the bubble dissolving means dissolving bubbles in the liquid; A gas dissolving device comprising:

[0008] (Section 2) a joint for connecting the gas-liquid mixer and the gas bubble dissolving means; The bubble generating means is disposed within the joint. Item 1. A gas dissolving device according to item 1.

[0009] (Section 3) The air bubble dissolving means is a spiral pipe through which a liquid containing air bubbles flows. Item 1. A gas dissolving device according to item 1.

[0010] (Section 4) The spiral pipe is wound around the gas-liquid mixer. Item 3. A gas dissolving device according to item 3.

[0011] (Section 5) A gas dissolving device according to any one of items 1 to 4, a circulation system for circulating liquid through the gas dissolving device; a gas introduction section that introduces a gas into a liquid upstream of the gas dissolving device; A gas dissolution system comprising:

[0012] "Upstream" refers to the flow of the liquid. Effect of the Invention

[0013] In the gas dissolving device of the present invention, the gas bubble dissolving means is disposed outside the gas-liquid mixer. Furthermore, the gas bubble dissolving means is removable. Therefore, a gas bubble dissolving means having a certain structure can be easily changed to a gas bubble dissolving means having a different structure. This allows the use of an optimal gas bubble dissolving means depending on the solubility of the gas in the liquid (i.e., the ease with which the gas dissolves in the liquid). [Brief description of the drawings]

[0014] [Figure 1A] FIG. 2 is a front view of the gas dissolving device. [Figure 1B] FIG. 2 is a plan view of the gas dissolving device. [Figure 2A] FIG. 2 is a cross-sectional view taken along line IIA-IIA in FIG. 1B. [Figure 2B] FIG. 1B is a cross-sectional view taken along line IIB-IIB in FIG. 1A. [Figure 2C] FIG. 1B is a cross-sectional view taken along line IIC-IIC in FIG. 1A. [Diagram 3] FIG. 1 is a schematic diagram of a gas dissolution system. [Figure 4] FIG. 13 is a front view showing a modified example of the air bubble dissolving means. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The gas dissolving device 100 and the gas dissolving system 200 of the present invention will be described with reference to the drawings.

[0016] <1. Gas dissolving device> The gas dissolving device 100 is a device for dissolving a gas in a liquid. In one example, the liquid is water and the gas is air. However, the types of liquid and gas are not limited thereto.

[0017] 1 and 2C, the gas dissolving device 100 includes a gas-liquid mixer 10, a joint 20, a gas bubble generating means 30 (see FIG. 2C), and a gas bubble dissolving means 40. The gas bubble dissolving means 40 is disposed outside the gas-liquid mixer 10. The gas bubble dissolving means 40 is detachably coupled to the gas-liquid mixer 10 via the joint 20.

[0018] <1-1. Bubble generator> 1A to 2C, the gas-liquid mixer 10 will be described. The gas-liquid mixer 10 mixes gas and liquid to generate a gas-liquid mixed liquid.

[0019] As shown in FIGS. 1A to 2A, the gas-liquid mixer 10 includes a casing 11, a first partition wall 12, a second partition wall 13, an inlet pipe 14, and an outlet pipe 15.

[0020] The casing 11 has a cylindrical appearance. The casing 11 includes a circular bottom wall 111, a peripheral wall 112, and a top wall 113. The peripheral wall 112 is cylindrical and rises from the bottom wall 111. The top wall 113 is circular and closes the top end of the casing 11.

[0021] The bottom wall 111 and the top wall 113 are hermetically joined to the peripheral wall 112. By "hermetically joined" it is meant that the multiple members are joined to each other such that liquid and gas do not leak from the joints of the multiple members (e.g., the joints of the bottom wall 111 and the peripheral wall 112). In one embodiment, the bottom wall 111 and the top wall 113 are welded to the peripheral wall 112.

[0022] The first partition wall 12 is circular. As shown in Fig. 2A, the first partition wall 12 is disposed inside the casing 11 and below the upper wall 113. The outer peripheral surface of the first partition wall 12 is airtightly joined to the inner peripheral surface of the peripheral wall 112. The first partition wall 12 has a through-hole 12a at its center that passes through the first partition wall 12.

[0023] The second partition wall 13 is airtightly joined to the lower surface of the first partition wall 12. The second partition wall 13 is cylindrical. The second partition wall 13 is provided so that its central axis coincides with the center of the through hole 12a of the first partition wall 12. The inner diameter of the second partition wall 13 is approximately the same as the diameter of the through hole 12a. A space 131 in the second partition wall 13 communicates with the through hole 12a. The outer diameter of the second partition wall 13 is smaller than the inner diameter of the peripheral wall 112. Therefore, a space 132 exists between the outer peripheral surface of the second partition wall 13 and the inner peripheral surface of the peripheral wall 112. The space 132 is separated from the space 131 by the second partition wall 13.

[0024] The lower end of the second partition wall 13 is not in contact with the upper surface of the bottom wall 111, and is located higher than the upper surface of the bottom wall 111. Therefore, a gap exists between the lower end of the second partition wall 13 and the upper surface of the bottom wall 111.

[0025] The inlet pipe 14 is made of a cylindrical pipe. A pipe (for example, a liquid supply pipe 240 described later) that sends liquid and gas to the gas-liquid mixer 10 is connected to the inlet pipe 14. The inlet pipe 14 is airtightly connected to the casing 11. As shown in FIG. 2A, the inlet pipe 14 is provided slightly below the first partition wall 12. As shown in FIG. 2B, the inlet pipe 14 is disposed in the tangential direction of the outer periphery of the peripheral wall 112. The inlet pipe 14 penetrates the peripheral wall 112 and communicates with the space 132.

[0026] The outlet pipe 15 is made of a cylindrical pipe. As shown in FIG. 1A, the outlet pipe 15 is airtightly connected to the casing 11. A joint 20 is airtightly connected to the outlet pipe 15. The outlet pipe 15 is provided above the first partition wall 12. As shown in FIG. 2C, the outlet pipe 15 is disposed on the opposite side to the inlet pipe 14 with respect to the central axis of the peripheral wall 112, and is disposed in the tangential direction of the outer periphery of the peripheral wall 112. The outlet pipe 15 penetrates the peripheral wall 112 and communicates with the space above the first partition wall 12. Therefore, the liquid that has passed through the through hole 12a is discharged from the gas-liquid mixer 10 through the outlet pipe 15.

[0027] <1-2. Joints> 1A, the joint 20 airtightly connects the gas-liquid mixer 10 and the air bubble dissolving means 40. As the joint 20, a known joint such as a one-touch joint such as a coupler or a screw joint can be used.

[0028] <1-3. Means for generating bubbles> The bubble generating means 30 generates minute bubbles in the liquid. The bubble generating means 30 is provided in the joint 20. The bubble generating means 30 may be formed integrally with the joint 20 or may be separate from the joint 20 (i.e., may be detachably attached to the joint 20). As shown in FIG. 2C, the bubble generating means 30 includes an orifice plate 31. The orifice plate 31 has a through hole (orifice) 31a at its center. The through hole 31a has a diameter capable of generating a pressure change in the liquid passing through the through hole 31a and generating bubbles in the liquid after passing through the through hole 31a. The liquid that has passed through the through hole 31a may contain bubbles such as microbubbles and nanobubbles.

[0029] <1-4. Mechanism of generation of liquid containing bubbles> Here, the mechanism by which liquid containing minute bubbles is generated by the gas-liquid mixer 10 and the bubble generating means 30 will be described with reference to Figs. 2A to 2C.

[0030] A gas-containing liquid is supplied to the gas-liquid mixer 10 by a pump or the like.

[0031] The gas-containing liquid supplied to the gas-liquid mixer 10 through the inlet pipe 14 moves downward while swirling in the space 132 (in FIG. 2B, the flow direction of the liquid is shown by an arrow as a schematic diagram). In the process in which the gas-containing liquid swirls at high speed in the space 132, the gas and the liquid are mixed, and a shear force acts on the bubbles, causing the bubbles to become finer. When the gas-containing liquid moves to the bottom wall 111, it flows into the space 131 from a gap between the lower end of the second partition wall 13 and the upper surface of the bottom wall 111. The gas-containing liquid rises while swirling in the space 131. Since the cross-sectional area of ​​the space 131 is smaller than the cross-sectional area of ​​the space 132, when the gas-containing liquid flows into the space 131, the flow rate of the gas-containing liquid increases. In the process in which the gas-containing liquid flows through the space 131, the gas and the liquid are mixed, and a shear force acts on the bubbles, causing the bubbles to become finer.

[0032] The gas-containing liquid rising in the space 131 passes through the through hole 12a and the outlet pipe 15 in this order, and reaches the gas bubble generating means 30. The gas-containing liquid is subjected to a sudden change in pressure when passing through the through hole 31a of the gas bubble generating means 30. As a result, large gas bubbles in the liquid are crushed and reduced in size.

[0033] In this manner, a large number of minute bubbles are generated in the liquid after passing through the through-hole 31a due to the crushing of the bubbles by the high-speed swirling flow (i.e., generation of minute bubbles by the swirling flow method) and the crushing of the bubbles by the sudden pressure change (i.e., generation of minute bubbles by the Venturi method). The bubble-containing liquid that has passed through the through-hole 31a flows into the bubble dissolving means 40.

[0034] <1-5. Means for dissolving air bubbles> Next, the air bubble dissolving means 40 will be described with reference to Fig. 1A. The air bubble dissolving means 40 dissolves minute air bubbles generated in the liquid into the liquid. The inlet of the air bubble dissolving means 40 is airtightly coupled to the joint 20.

[0035] In one embodiment, the air bubble dissolving means 40 is a pipe through which the air bubble-containing liquid can pass. The material of the pipe is not particularly limited, and may be made of metal or resin. The pipe preferably has at least one curved section, because the air bubble-containing liquid experiences higher resistance when passing through a curved section than through a straight section, making it easier for the air bubbles to dissolve in the liquid. The air bubble dissolving means 40 is preferably a spiral pipe. It is more preferable that the spiral pipe is wound around the outer circumferential surface of the peripheral wall 112. The air bubble-containing liquid flows downward through the spiral pipe wound around the outer circumferential surface of the peripheral wall 112.

[0036] When the air bubble-containing liquid flows into the air bubble dissolving means 40, the air bubbles dissolve in the liquid due to the resistance encountered when passing through the air bubble dissolving means 40. The liquid with the dissolved gas is discharged from the outlet of the air bubble dissolving means 40.

[0037] <2. Gas dissolution system> 3, a gas dissolving system 200 using the gas dissolving device 100 will be described. In the following, a case where outside air (air) is introduced into a liquid will be described, but as already mentioned, the gas is not limited to outside air.

[0038] The gas dissolution system 200 includes a tank 210 for containing liquid, a pump 220, a gas dissolution device 100, a supply pipe 230 for sending the liquid in the tank 210 to the pump 220, a liquid delivery pipe 240 for sending the liquid from the pump 220 to the gas dissolution device 100, a discharge pipe 250 for discharging the liquid from the gas dissolution device 100 into the tank 210, a first gas introduction section 260 connected to the supply pipe 230, and a second gas introduction section 270 connected to the first gas introduction section 260.

[0039] The tank 210 , the pump 220 , the supply pipe 230 , the liquid delivery pipe 240 and the discharge pipe 250 function as a circulation system for circulating the liquid through the gas dissolving apparatus 100 and repeatedly treating the liquid through the gas dissolving apparatus 100 .

[0040] The first gas introduction part 260 and the second gas introduction part 270 are made of pipes. The first gas introduction part 260 and the second gas introduction part 270 are provided to introduce outside air or a gas other than outside air, such as nitrogen, into the liquid.

[0041] By driving the pump 220, liquid is sucked up from the tank 210 into the supply pipe 230. In addition, by driving the pump 220, outside air is sucked from the first gas introduction part 260 and introduced into the supply pipe 230. If necessary, a gas other than outside air, such as nitrogen, can be introduced into the supply pipe 230 from the second gas introduction part 270 instead of the outside air introduced from the first gas introduction part 260.

[0042] The liquid and air flowing inside the supply pipe 230 are supplied to the gas dissolving device 100 through a liquid delivery pipe 240 .

[0043] When the liquid and air are supplied to the gas dissolving device 100, the liquid and the air are thoroughly mixed by the gas dissolving device 100, and the air is dissolved in the liquid.

[0044] The liquid with dissolved air is returned to the tank 210 through the discharge pipe 250 .

[0045] The liquid returned to the tank 210 is again supplied to the gas dissolving device 100 together with outside air by the pump 220, and is again treated by the gas dissolving device 100. In this manner, the treatment of the liquid by the gas dissolving device 100 is repeated.

[0046] Shortly after the start of operation of the gas dissolving system 200, air is not very dissolved in the liquid and the liquid has not yet reached a saturated state, so air dissolves in the liquid. As the circulation process by the gas dissolving system 200 progresses, the liquid approaches a saturated state, so air gradually becomes unable to dissolve in the liquid and exists in the liquid in the form of bubbles. Therefore, a large number of tiny air bubbles exist in the liquid after the circulation process by the gas dissolving system 200.

[0047] The gas dissolving system 200 can generate liquid containing a large number of ultra-fine bubbles, such as microbubbles and nanobubbles. Therefore, the gas dissolving system 200 can be used, for example, to generate water for cultivating fish and water for transporting fish, to generate water for washing items such as pipes, bathtubs, and factory equipment, and to generate water for cultivating and washing agricultural crops.

[0048] <3. Examples> The solubility of air in water was examined according to the length of the air bubble dissolving means 40. In the experiment, the gas dissolving system 200 shown in FIG. 3 was used. A resin tube was used as the air bubble dissolving means 40. In Example 1, the tube length of the air bubble dissolving means 40 was 250 mm. In Example 2, the tube length of the air bubble dissolving means 40 was 1000 mm. In Example 3, the tube length of the air bubble dissolving means 40 was 2000 mm. 25 liters of water was placed in the tank 210. During the experiment, the water temperature was maintained between 13°C and 14°C. The first gas introduction part 260 was opened, and air was sucked from the first gas introduction part 260. The amount of air sucked from the first gas introduction part 260 was adjusted to 0.5 ml / min. The second gas introduction part 270 was closed, and gas was not sucked from the second gas introduction part 270. In each example, operation was carried out for 60 minutes, and after 60 minutes, the oxygen concentration of the water in the tank 210 was measured using a digital dissolved oxygen meter DO-5509 manufactured by Mother Tools Corporation.

[0049] The oxygen concentration in Example 1 was 13.5 mg / L. The oxygen concentration in Example 2 was 14.9 mg / L. The oxygen concentration in Example 3 was 18.0 mg / L. These results show that the solubility of gas in liquid can be changed by adjusting the length of the bubble dissolving means 40.

[0050] <4. Effects> In the gas dissolving device 100 of the present invention, the bubble dissolving means 40 is disposed outside the gas-liquid mixer 10. The bubble dissolving means 40 is removable. Therefore, the gas-liquid mixer 10 is not changed, and the bubble dissolving means 40 can be changed to a bubble dissolving means 40 having various structures, thereby changing the solubility of the gas in the liquid. For example, the solubility of the gas in the liquid can be increased by using a bubble dissolving means 40 having a structure in which the liquid stays in the bubble dissolving means 40 for a longer time, or a structure in which a stronger resistance is applied to the liquid. On the other hand, the solubility of the gas in the liquid can be suppressed by using a bubble dissolving means 40 having a structure in which the liquid stays in the bubble dissolving means 40 for a shorter time, or a structure in which a weaker resistance is applied to the liquid.

[0051] The joint 20 can be easily removed from the gas-liquid mixer 10 and the bubble dissolving means 40. Therefore, since the bubble generating means 30 is provided in the joint 20, the bubble generating means 30 having a through hole 31a of a certain diameter can be easily replaced with the bubble generating means 30 having a through hole 31a of a different diameter by simply replacing the joint 20.

[0052] The air bubble dissolving means 40 being a spiral pipe makes it possible to realize an air bubble dissolving means 40 with a simple structure. When the air bubble dissolving means 40 is a spiral pipe, as shown in Fig. 4, for example, the residence time of the liquid in the air bubble dissolving means 40 can be changed by changing the length of the pipe (the number of turns), and the magnitude of the resistance applied to the liquid can be changed by changing the inner diameter of the pipe.

[0053] The gas bubble dissolving means 40, which is a spiral pipe, is wound around the gas-liquid mixer 10, so that the gas dissolving device 100 can be made compact.

[0054] The gas dissolution system 200 can produce a liquid containing a large number of tiny gas bubbles.

[0055] <5. Modifications> The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the scope of the present invention. Modifications of the present invention will be described below. The modifications described below can be applied to the above-described embodiment alone or in appropriate combination without departing from the scope of the present invention.

[0056] (5-1) The air bubble generating means 30 may be provided in the outlet pipe 15 instead of inside the joint 20, or may be provided in the inlet of the air bubble dissolving means 40.

[0057] (5-2) Instead of using the negative pressure of the pump 220 to suck in gas from the outside, gas may be forced into the first gas introduction part 260 or the second gas introduction part 270.

[0058] (5-3) The air bubble dissolving means 40 is not limited to a spiral shape, and may be, for example, a corrugated shape.

[0059] (5-4) In addition to or instead of the first gas introducing part 260 and the second gas introducing part 270, a gas introducing part may be coupled to the liquid sending tube 240. [Explanation of symbols]

[0060] 100 Gas dissolving device 10 Gas-liquid mixer 20 Joints 30 Bubble generating means 40 Air bubble dissolving means 200 Gas Dissolution System 210 Tank (part of the circulation system) 220 Pump (part of the circulation system) 230 Supply pipe (part of the circulation system) 240 Liquid delivery pipe (part of the circulation system) 250 Exhaust pipe (part of the circulation system) 260 Gas Inlet 270 Gas introduction section

Claims

1. a gas-liquid mixer that mixes the gas and the liquid to generate a gas-liquid mixed liquid; A bubble generating means for generating bubbles in the gas-liquid mixture; a removable bubble dissolving means that is disposed outside the gas-liquid mixer and separate from the gas-liquid mixer, the bubble dissolving means dissolving bubbles in the liquid; A gas dissolving device comprising:

2. a joint for connecting the gas-liquid mixer and the gas bubble dissolving means; The bubble generating means is disposed within the joint. The gas dissolving device according to claim 1 .

3. The air bubble dissolving means is a spiral pipe through which a liquid containing air bubbles flows. The gas dissolving device according to claim 1.

4. The spiral pipe is wound around the gas-liquid mixer. The gas dissolving device according to claim 3.

5. A gas dissolving device according to any one of claims 1 to 4; a circulation system for circulating liquid through the gas dissolving device; a gas introduction section that introduces a gas into a liquid upstream of the gas dissolving device; A gas dissolution system comprising:

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