JP2013128869A - Gas dissolved water producing apparatus and method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus which perfectly dissolves a gas fed to pure water of a small flow rate, and produces gas dissolved water having a stable specific resistance value of ≤1 MΩ cm.SOLUTION: In the gas dissolved water producing apparatus 11, a gas is injected into a pure water inflow pipe of feeding pure water to produce gas dissolved water in which the gas is dissolved at a fixed concentration. The apparatus includes: a T-type conduit 12; a gas feed pipe 15 which is inserted from one socket of the T-type conduit to the position of the center of a T-type joining part and in which a base part is sealed; a pure water inflow pipe 13 of feeding pure water vertically in a direction to be fed with the gas from the other one socket of the T-type conduit; and a pure water outflow pipe 14 composed of a first pure water outflow pipe 14a connected to one socket not provided by both of the gas feed pipe 15 and pure water inflow pipe 13 of the T-type conduit, and the second pure water outflow pipe 14c connected to the downstream of the first pure water outflow pipe 14a.

Description

  The present invention relates to a gas-dissolved water production apparatus and a gas-dissolved water production method having a small flow rate.

  Conventionally, in the manufacturing process of a semiconductor device, ultrapure water has been used for cleaning a semiconductor wafer. For example, in the substrate cleaning process, particles adhering to the surface of the substrate are removed by spraying cleaning water such as pure water onto the substrate.

  By the way, it is known that when pure water is discharged at a high pressure or a polishing brush or the like is rotated at a high speed, the entire surface of the substrate is charged because the specific resistance of pure water is high. When the amount of charge on the substrate surface is increased, there are problems that particles are reattached after cleaning, and an oxide film and a metal thin film forming a semiconductor element formed on the wafer are destroyed by electrostatic discharge.

  As a measure for preventing such destruction of the semiconductor element, the electrical resistivity of pure water is reduced to suppress the generation of static electricity.

For example, Patent Document 1 discloses a method for preventing charging of the substrate surface by reducing the electrical resistivity by dissolving carbon dioxide (CO ₂ ) gas in ultrapure water that is treated water.

In this way, hydrogen carbonate ions are dissociated and dissolved in so-called carbonated water in which carbon dioxide (CO ₂ ) gas is dissolved in ultrapure water, but the electrical resistivity can be lowered by the hydrogen carbonate ions. It is possible to reduce the electrostatic charge on the wafer and prevent the semiconductor element from being destroyed by electrostatic discharge.

  Further, at the stage after the drying process after cleaning, the carbon dioxide gas (dissolved in the carbonated water) disappears as a gas on the wafer surface, and there is an advantage that no trace of impurity residue is left.

  Further, Patent Document 2 discloses a device for generating microbubbles and suppressing coalescence of bubbles to dissolve in water in order to stabilize the dissolved gas concentration of such gas-dissolved water. Such an apparatus is an apparatus in which liquid introduction parts having different flow cross-sectional areas are coupled by a conical coupling part, and gas dissolved water in which gas bubbles are completely dissolved is generated.

  Further, for example, in the production of carbon dioxide-dissolved water, it is necessary to dissolve carbonic acid by a predetermined concentration so that the specific resistance value of the carbon dioxide-dissolved water is constant.

  Therefore, as described in Patent Document 3, by measuring the specific resistance value of the produced carbon dioxide-dissolved water and performing feedback control of the carbon dioxide flow rate supplied using the measured value, the specific resistance of the gas-dissolved water is obtained. The value is made constant.

  As described in Patent Document 4, carbon dioxide gas is dissolved in only a part of pure water to produce a high concentration carbon dioxide dissolved water, and the dissolved water and pure water are further mixed to obtain a predetermined specific resistance. There is also a method for obtaining carbon dioxide-dissolved water having a value.

  In recent years, gas other than carbon dioxide gas, for example, dissolved water in which hydrogen, ozone, oxygen, and nitrogen gas are dissolved is also widely used. In the case of producing ultrapure water in which nitrogen gas is dissolved at a predetermined concentration. As with the production of carbon dioxide-dissolved water, control of the amount of gas to be dissolved becomes a problem. In Patent Document 5, the gas solubility is adjusted by passing nitrogen gas through the gas dissolution membrane and further feedback controlling the gas supply amount.

JP 2008-153322 A Japanese Patent Laid-Open No. 2003-230824 Japanese Patent Publication No. 07-067554 Patent No. 3690569 Patent 4470101

  By the way, carbon dioxide (carbonic acid) dissolves in water to generate bicarbonate ions and carbonate ions. Therefore, the solubility in water is relatively large, and the dissolution itself is easy. However, even if the carbon dioxide supply amount is controlled, the specific carbon dioxide gas supply amount fluctuates as the pure water supply pressure and supply flow fluctuate. Therefore, the specific resistance remains constant. It is difficult to make. Accordingly, various devices such as feedback control and mixing of pure water and high-concentration carbon dioxide-dissolved water in which carbon dioxide is dissolved in advance are required. In addition, when the apparatus is further downsized and dissolved water with a small flow rate is produced, this tendency is increased, and it is difficult to obtain carbon dioxide-dissolved water having a specific resistance value of 1 MΩ · cm or less. .

  As a result of intensive research to cope with such problems, the inventors of the present invention, when the flow rate of pure water is small, bubbles of injected carbon dioxide tend to adhere to the inner wall of the pipe, and adhere to the inner wall of the pipe. Another bubble is bonded to the bubble and stays on the wall surface. However, it eventually desorbs from the wall surface and dissolves, and as a result, the carbon dioxide concentration temporarily rises, causing the resistivity to become unstable. I found out. Further, in a small apparatus, since the pipe is thin, the area occupied by the inner wall of the pipe that is in contact with water in the pipe with respect to the flow rate is relatively large, and it has been found that this phenomenon becomes remarkable. In addition, in the conventional case, it was considered that the pure water flow was turbulent in order to quickly mix and dissolve, but in the case of a small flow rate, it should be a laminar flow. We also obtained the knowledge that is effective.

  Furthermore, as a result of repeated research, the present inventors have made it possible to expel a pure water flow in a direction crossing the gas flow path at the outlet of the end of the gas supply pipe because the dissolution becomes faster as the bubble diameter of the dissolved gas becomes smaller. As a result, bubbles are generated at the outlet, and at the same time, a shearing force is applied to the bubbles and sheared before the bubbles merge and grow at the end of the gas supply pipe, so that the bubbles become smaller and the dissolution proceeds quickly. It was.

  The present invention has been made based on such knowledge, and when a gas is injected from a gas supply pipe into a pipe through which a small amount of pure water flows and dissolved, the pure water flow is perpendicular to the flow path from which the gas is ejected. The gas dissolved water having a stable specific resistance value of 1 MΩ · cm or less by making the bubbles as fine as possible, and preventing the bubbles from adhering to the inner wall of the pipe by making the water flow a laminar flow downstream. It is an object of the present invention to provide a gas-dissolved water production apparatus that can be manufactured and can be miniaturized.

  That is, the first embodiment of the gas-dissolved water production apparatus of the present invention is such that gas is injected into a pure water inflow pipe for supplying pure water, and gas-dissolved water for producing gas-dissolved water in which the gas dissolves at a constant concentration. In the manufacturing apparatus, a T-type pipe, a gas supply pipe that is inserted from one receiving port of the T-type pipe to the position of the center of the T-type coupling portion and whose base is sealed, and the T-type pipe Neither a pure water inflow pipe for supplying pure water perpendicularly to a direction in which the gas is supplied from another one receiving port, nor the gas supply pipe or the pure water inflow pipe of the T-type pipe 1 A pure water outflow pipe comprising a first pure water outflow pipe and a second pure water outflow pipe connected downstream of the first pure water outflow pipe, connected to one receiving port. And

  A second embodiment of the gas-dissolved water production apparatus of the present invention is characterized in that the pure water inflow pipe is inserted to the center of the coupling portion of the T-shaped pipe line and the base is sealed.

  Specifically, the pure water supply flow rate is 0.1 to 2 L / min, and the pure water flow in a part or all of the flow path after the gas and the pure water are mixed is a laminar flow. Preferably there is.

  More specifically, it is preferable that the pipe diameter of the second pure water outflow pipe is larger than the pipe diameter of the first pure water outflow pipe.

  The Reynolds number in the pure water outflow pipe or the second pure water outflow pipe is preferably less than 2300.

  Moreover, it is preferable that the Reynolds number in the said pure water inflow pipe is 2300 or more, or 2 times or more of the Reynolds number of a 2nd pure water outflow pipe or the said pure water outflow pipe. That is, the gas supplied from the gas supply pipe is a turbulent flow from the pure water inflow pipe, or a laminar flow more than twice the Reynolds number of the second pure water outflow pipe or the pure water outflow pipe, Part or all of the pure water flow in the flow path after joining the supplied pure water and after the gas and the pure water are mixed is a laminar flow, and the gas and the pure water are mixed in the vertical direction Therefore, the supplied gas is sheared and can be quickly dissolved.

  More specifically, it is preferable that the first outflow pipe part and the second outflow pipe part are connected via a tapered pipe that expands downstream. Further, carbon dioxide can be used as the gas.

  That is, the gas-dissolved water production apparatus of the present invention is made by finding the relationship between the Reynolds number and the flow in the pipe, and a predetermined flow velocity and pipe inner diameter are selected, and the Reynolds number is determined as described above. Thus, it is possible to produce gas dissolved water in which the supplied gas is uniformly dissolved and the specific resistance is stable.

  The gas-dissolved water production method of the present invention includes a T-type pipe, a gas supply pipe that is inserted from one receiving port of the T-type pipe to the position of the center of the T-type joint, and the base is sealed, A pure water inflow pipe for supplying pure water perpendicularly to a direction in which the gas is supplied from another one receiving port of the T type pipe, and the gas supply pipe and the pure water inflow pipe of the T type pipe A pure water outflow pipe, which is connected to one receiving port not provided with any of the above, and includes a first pure water outflow pipe and a second pure water outflow pipe connected downstream of the first pure water outflow pipe. A method for producing dissolved gas with a dissolved gas production apparatus, comprising a laminar flow of pure water in a part or all of a flow path after the gas and pure water are mixed. And

  Provided is an apparatus and method for completely dissolving a gas supplied in a small flow rate of pure water and producing gas-dissolved water having a stable specific resistance value of 1 MΩ · cm or less.

FIG. 1 is a side sectional view schematically showing a gas-dissolved water production apparatus according to a first embodiment of the present invention. FIG. 2A is a side sectional view schematically showing a gas-dissolved water production apparatus according to the second embodiment of the present invention. FIG. 2B is a side sectional view schematically showing a T-shaped pipe portion in the gas-dissolved water producing apparatus according to the second embodiment of the present invention. FIG. 3 is a graph showing specific resistance values of carbon dioxide-dissolved water produced using the gas-dissolved water producing apparatus according to the first embodiment of the present invention. FIG. 4 is a graph showing specific resistance values of carbon dioxide-dissolved water produced using the gas-dissolved water producing apparatus according to the first embodiment of the present invention. FIG. 5 is a graph showing specific resistance values of carbon dioxide-dissolved water produced using the gas-dissolved water producing apparatus according to the second embodiment of the present invention. FIG. 6 is a graph showing specific resistance values of carbon dioxide-dissolved water produced using a gas-dissolved water producing apparatus that is a comparative example of the first embodiment of the present invention. FIG. 7 is a graph showing specific resistance values of carbon dioxide-dissolved water produced using a gas-dissolved water producing apparatus that is a comparative example of the first embodiment of the present invention. FIG. 8 is a graph showing specific resistance values of carbon dioxide-dissolved water produced using a gas-dissolved water producing apparatus that is a comparative example of the second embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this specification, “pure water” means water having a specific resistance of 10 MΩ · cm or more and TOC (total organic carbon) of 0.1 mg / L or less, and “ultra pure water” means specific resistance. Water whose value is 17 MΩ · cm or more and TOC (total organic carbon) is 10 μg / L or less.

  FIG. 1 is a side sectional view schematically showing a gas-dissolved water production apparatus 11 according to a first embodiment of the present invention, which is an apparatus for producing carbon dioxide-dissolved water (carbonated water). In the gas-dissolved water production apparatus 11 of the first embodiment of the present invention, the T-shaped joint 12 is arranged vertically on the straight pipe portion 12a side, the pure water inflow pipe 13 is connected to the branch pipe portion 12b, and the straight pipe The pure water outflow pipe 14 is connected to the upper side of the portion 12a, and the gas supply pipe 15 is inserted from the lower side of the straight pipe portion 12a to the position on the center line of the branch pipe portion 12b. 12 is configured to be liquid-tightly sealed with a sealing member.

  The pure water outflow pipe 14 is connected to a first pure water outflow pipe 14a having the same dimensions as the pure water inflow pipe 13 and a tapered pipe portion 14b that expands downstream from the first outflow pipe portion. 2 pure water outflow pipes 14c.

  In the gas dissolved water production apparatus 11 of the present embodiment, the pure water outflow pipe 14 is disposed above the T-shaped joint and the gas supply pipe 15 is inserted from below, but the pure water outflow pipe 14 is configured. The gas supply pipe 15 may be arranged on the lower side, the gas supply pipe 15 may be installed on the branch pipe portion 12b, and the pure water inflow pipe 13 may be installed on either the upper side or the lower side. An effect can be obtained. Further, the straight pipe portion 12a of the T-shaped joint 12 can be installed in a direction other than the vertical direction.

  Carbon dioxide gas is supplied from the gas supply pipe 15, and a small amount of pure water is supplied from the pure water inflow pipe 13 and mixed in the orthogonal direction inside the T-shaped joint 12.

  The mixed pure water containing gas bubbles flows out to the first pure water outflow pipe 14a and is further mixed. The pure water flow is preferably a turbulent flow having a Reynolds number of 2300 or more as a whole in the flow region from the inside of the T-shaped joint 12 to the inside of the pipe portion 14a. However, it is more than twice the Reynolds number of the second pure water outflow pipe 14c. The same effect can be obtained with the laminar flow. The pure water in which the gas is dissolved subsequently flows out into the second pure water outflow pipe 14c. In the pipe portion 14c, the pure water flow is preferably a laminar flow having a Reynolds number of less than 2300 as a whole.

  Examples of water to be supplied include ultrapure water and pure water used in semiconductor manufacturing processes. The flow rate of pure water in this apparatus is, for example, 0.2 L / min, and the specific resistance is 10 to 18.2 MΩ · cm. The supply amount of carbon dioxide is 0.08 mL / min (at 20 ° C. and 1 atm).

  For example, the dimensions of the pure water inflow pipe 13 are an outer diameter of 6 mm and an inner diameter of 4 mm, and the outer shape of the gas supply pipe 15 is about 2 mm and the inner diameter is 0.13 mm. The gas supply pipe 15 is a SUS tube or the like, and the inner diameter is preferably φ0.5 mm or less, more preferably φ0.3 mm or less, and the specific resistance value of carbon dioxide-dissolved pure water becomes more stable as the diameter is reduced. .

  The first pure water outflow pipe 14a is preferably a pipe having a circular cross section with a smooth interior in order to make the pure water flow turbulent as a whole. Further, as the first pure water outflow pipe 14a, a pipe formed of SUS, PFA, PTFE or the like can be used.

  The second pure water outflow pipe 14c is preferably configured so that the pure water flow becomes a laminar flow as a whole. The pure water flow is often turbulent at the connection portion of the pipe, but the tapered pipe portion 14b and the second flow water pipe 14c are preferably connected so as to minimize these effects. As for the dimensions of the pipe, the inner diameter of the second pure water outflow pipe 14c may be an inner diameter in which the pure water flow inside becomes a laminar flow, preferably φ20 mm or less, more preferably φ15 mm or less, and further preferably φ12 mm or less. It is. For example, the first outflow pipe portion 14a of the pure water outflow pipe 14 has the same dimensions as the pure water inflow pipe 13, and the inner diameter of the second outflow pipe portion 14c is φ10 mm.

  The first pure water outflow pipe 14 a of the pure water outflow pipe 14 is preferably the same size as the pure water inflow pipe 13 in terms of the structure of the T-shaped joint 12, but is not limited to the same size. Although the dimension of the second pure water outflow pipe 14c can be changed as appropriate, it is necessary to use a pipe having an inner diameter sufficient to form a laminar flow with respect to the pure water flow rate used.

  That is, in the region where pure water and gas are mixed, the pure water flow is turbulent, the gas is quickly dissolved, the pure water flow is laminar in the second outflow pipe portion 14c, and adheres to the inner wall surface of the pipe. Air bubbles can be prevented from being combined.

  The first pure water outflow pipe 14a is preferably a straight pipe, and is preferably as short as possible in order to prevent the pure water flow from being turbulent in the first outflow pipe portion and causing bubbles to adhere to the inner wall surface of the pipe. It is also possible to reduce the overall size.

  The shape of the second pure water outflow pipe 14c may be helical.

The Reynolds number Re ₁ of the pure water flow in the pure water inflow pipe 13 is preferably 2300 or more or twice or more than the Reynolds number of the second pure water outflow pipe. The Reynolds number Re ₂ is preferably less than 2300 pure water in the second pure water outlet pipe 14c, more preferably 1500 or less.

When Re ₁ is less than 2300, the shearing of bubbles by pure water at the tip (exit) of the gas supply pipe 15 becomes insufficient, the bubbles become larger and the dissolution becomes insufficient, so the specific resistance value of the dissolved water is not stable. . When Re ₂ is 2300 or more, bubbles adhere to the inner wall surface of the pipe, and the attached bubbles peel and dissolve, so the specific resistance value of the dissolved water is not stable. By determining the Reynolds number as described above, the supplied gas can be rapidly and completely dissolved to produce gas-dissolved water having a stable specific resistance value.

The Reynolds number Re, as shown in (1) below, depends on the kinematic viscosity ν (m ² / s) of the liquid, the velocity (flow velocity) V (m / s), and the diameter d (m) of the tube through which the fluid flows. A dimensionless constant to be determined.

  Re = Vd / ν (1)

  In general, when the cross section of the pipe is circular, the fluid changes from laminar flow to turbulent flow in the range of 2700 to 4000 Re of fluid flowing in the laminar flow, and the Re of fluid flowing in the turbulent flow is It is known that when it becomes 2000 or less, it changes from a turbulent flow to a laminar flow. In this specification, a pure water flow having a Reynolds number of 2300 or more is referred to as a turbulent flow, and a pure water flow having a Reynolds number of less than 2300 is referred to as a laminar flow.

  FIG. 2A is a side sectional view schematically showing a gas-dissolved water production apparatus 21 according to a second embodiment of the present invention, which is an apparatus for producing carbon dioxide-dissolved water (carbonated water). In the gas-dissolved water production apparatus 21 of the second embodiment of the present invention shown in FIG. 2A, the T-shaped joint 22 is arranged vertically on the straight pipe part 22a side, and the pure water inflow pipe 23 is provided in the branch pipe part 22b. It is inserted to the center of the straight pipe portion, and the space between the pure water inflow pipe 23 and the T-shaped joint 22 is liquid-tightly sealed with a sealing member. Further, the gas supply pipe 25 is inserted from the lower side of the straight pipe section 22a to a position on the center line of the branch pipe section 22b, and the gap between the gas supply pipe 25 and the T-shaped joint 22 is liquid-tightly sealed with a sealing member. The pure water outflow pipe 24 is connected to the upper side of the straight pipe portion 22a.

  In the present embodiment, the gas supply pipe 25 is inserted from below the T-shaped joint 22 and the pure water outflow pipe 24 is inserted above, but the gas supply pipe 25 is above and the pure water outflow pipe 24 is below. Even if the gas supply pipe 25 is installed in the branch pipe portion 22b and the pure water inflow pipe 23 is installed either above or below, the effect of the present invention can be obtained. . Further, the straight pipe portion 22a of the T-shaped joint may be installed in a direction other than the vertical direction.

  Carbon dioxide gas is supplied from the gas supply pipe 25, and a small amount of pure water is supplied from the pure water supply pipe 23, and mixed in the orthogonal direction inside the T-shaped joint 22.

  The flow rate of pure water, the specific resistance, and the supply amount of carbon dioxide in this apparatus are the same as those in the apparatus in the first embodiment. Further, the dimensions of the tip nozzle portion of the pure water inflow pipe 23 are, for example, an outer diameter of 4 mm and an inner diameter of 2 mm, and the outer diameter, inner diameter, and material of the gas supply pipe 25 are the same as those of the apparatus of the first embodiment. In the pure water inflow pipe 23, the water flow is preferably turbulent as a whole, or is preferably a laminar flow that is twice or more the Reynolds number of the pure water outflow pipe 24. In addition, although it is preferable that the front-end | tip (jet outlet) of the pure water inflow tube 23 is a nozzle shape, a straight tube may be sufficient.

  The pure water inflow pipe 23 is preferably installed so that the distal end (exit) of the gas supply pipe 25 is on the extension line. The distal end of the gas supply pipe 25 and the distal end of the pure water inflow pipe 23 shown in FIG. It is desirable that the distance M (mm) in the following relationship be expressed by the following formula (2). R is the inner diameter (mm) of the pure water inflow pipe 23.

M ≦ 9.05 / R + 1.02 (2)

  M is preferably as small as possible. Specifically, it is preferably 5 mm or less, and more preferably 2 mm or less.

  The gas bubbles supplied from the gas supply pipe 25 are sheared by the pure water ejected from the tip nozzle part of the pure water inflow pipe 23 to become microbubbles, and the pure water flow is a turbulent flow as a whole. Therefore, it can be dissolved quickly.

  The pure water outflow pipe 24 has an inner diameter of 6 mm, and the water flow is preferably laminar as a whole in the pipe 24.

  A gas dissolution chamber 6 having an inlet 6a and an outlet 6b may be installed on the downstream side of the T-shaped joint 22. The pure water outflow pipe 24 is connected to the inflow port 6a of the gas dissolution chamber 6 to further dissolve the gas inside and to stabilize the specific resistance value by eliminating the concentration distribution in the pure water.

  The gas dissolution chamber 6 can be provided downstream of the T-shaped joints 12 and 22, but the pure water outflow pipes 14 and 24 or the second pure water outflow pipe 14c have the same volume or residence time as the chamber 6. Can be made to function in the same way. Further, the pipe diameter of the pipe downstream of the chamber 6 or downstream of the pure water outflow pipes 14, 24, that is, after the bubbles are completely dissolved, can be arbitrarily selected.

  The gas dissolution chamber 6 is for completely dissolving the gas inside, and is configured to have an inner diameter of 20 mm and an internal volume of 20 mL, for example.

  The dimensions of the pure water outflow pipe 24, the inner diameter and the flow rate of the gas dissolution chamber 6 can be changed as appropriate according to the overall dimensions of the apparatus, etc. It is preferable to configure so as to be ˜60 seconds, more preferably 5 to 30 seconds.

  The gas to be dissolved is not limited as long as it can be dissolved in pure water, and examples thereof include carbon dioxide, nitrogen, oxygen, and hydrogen.

  When the gas to be dissolved is nitrogen, the dissolved water can be used as ultrasonic cleaning water for a semiconductor manufacturing process or the like.

  Among these, carbon dioxide is particularly preferable, and the carbon dioxide-dissolved water is collected from the pure water outflow pipes 14 and 24 or the outlet 6b, and the specific resistance value is measured by the specific resistance value measuring device 7 or the like. It can be used for a process that requires antistatic treatment, a cleaning process, and the like.

  Moreover, according to the gas-dissolved water manufacturing method of the present invention, gas-dissolved water having a stable specific resistance value in a semiconductor manufacturing process or the like can be provided.

  Examples of the present invention will be described.

  The gas-dissolved water production apparatus 11 used in Examples 1 and 2 and Comparative Examples 1 to 3 simulates the apparatus of the first embodiment shown in FIG. The experimental conditions are as follows.

[Pure water] Specific resistance 18MΩ · cm
[Gas to be dissolved] Carbon dioxide gas [Supply pressure of carbon dioxide gas] 0.15 MPa
[Water temperature] 20 ℃
[Specific Resistance Measuring Device] HE-480R (Horiba Advanced Techno Co., Ltd.)

Example 1
The flow rate of pure water was 0.5 L / min, and the flow rate of carbon dioxide gas was 0.2 mL / min (at 20 ° C. and 1 atm).
The gas supply pipe 15 had an inner diameter of 0.13 mm and an outer diameter of 2 mm, and the pure water inflow pipe 13 had an inner diameter of 4 mm and a length of 15 mm.
The inner diameter of the first pure water outflow pipe 14a is 4 mm and the length is 15 mm, and the inner diameter of the second pure water outflow pipe 14c is 10 mm and the length is 100 mm.
The Reynolds number Re ₁₂ in the second pure water outflow pipe 14c was 1050. The Reynolds number Re ₁₁ in the pure water inflow tube 13 was 2600.
The specific resistance value of the carbon dioxide-dissolved water flowing out from the second pure water outflow pipe 14c was measured and shown in FIG.
In addition, when a part of the pure water outflow pipe 14c was made of glass and the inside was observed, it was confirmed that micro bubbles flowed through the central part of the pipe and gradually disappeared.

(Example 2)
The flow rate of pure water was 0.2 L / min, and the flow rate of carbon dioxide gas was 0.08 mL / min (at 20 ° C. and 1 atm). Other conditions were the same as in Example 1.
The Reynolds number Re ₂₂ in the second pure water outflow pipe 14c was 420. The Reynolds number Re ₂₁ in the pure water inflow tube 13 was 1050.
The specific resistance value of the carbon dioxide-dissolved water flowing out from the second pure water outflow pipe 14c was measured and shown in FIG.
At this time, when a part of the pure water outflow pipe 14 was made of glass and the inside was observed, it was confirmed that the microbubbles flow in the center of the pipe and gradually disappear.

(Comparative Example 1)
The inner diameter of the first pure water outflow pipe 14a was 10 mm and the length was 15 mm, and the inner diameter of the second pure water outflow pipe 14c was 10 mm and the length was 100 mm. (The inner diameters of the first pure water outflow pipe 14a and the second pure water outflow pipe 14c are the same as each other.) The pure water inflow pipe 13 has an inner diameter of 10 mm. Others were the same as in Example 1.
The Reynolds number Re ₃₁ in the pure water inflow tube 13 was 1050. The Reynolds number Re ₃₂ in the second pure water outflow tube 14c was 1050.
The specific resistance value of the carbon dioxide-dissolved water flowing out from the pure water outflow pipe 14c was measured and shown in FIG. In addition, when a part of the pure water outflow pipe 14 is made of glass and the inside is observed, the giant bubbles flow through the pipe as a whole, and a part of the pipe contacts the inner wall surface of the pipe. The state of adhering to the wall surface was confirmed.

(Comparative Example 2)
The inner diameter of the first pure water outflow pipe 14a was 4 mm and the length was 15 mm, and the inner diameter of the second pure water outflow pipe 14c was 4 mm and the length was 100 mm. (The first pure water outflow pipe 14a and the second pure water outflow pipe 14c have the same inner diameter, and are formed in an integral shape.)
The pure water inflow pipe 13 has an inner diameter of 4 mm. Others were the same as in Example 1.
The Reynolds number Re ₄₁ in the pure water inflow tube 13 was 2600. The Reynolds number Re ₄₂ in the second pure water outflow tube 14c was 2600.
When the specific resistance value of the carbon dioxide-dissolved water flowing out from the second pure water outflow pipe 14c was measured, the same result as in FIG. 6 was obtained.
At this time, when a part of the pure water outflow pipe 14 is made of glass and the inside is observed, the microbubbles flow through the pipe as a whole, and a part thereof contacts the inner wall surface of the pipe. And it was confirmed that it was attached to the wall surface.

(Comparative Example 3)
Example 2 was the same as Example 2 except that the inner diameter of the gas supply pipe 15 was set to φ0.8 mm.
The specific resistance value of the carbon dioxide-dissolved water flowing out from the second pure water outflow pipe 14c was measured and shown in FIG.
At this time, when a part of the pure water outflow pipe 14 was made of glass and the inside was observed, it was not confirmed that the giant bubbles flowed through the center of the pipe and the bubbles disappeared.

  Next, Example 3 and Comparative Example 4 using the gas-dissolved water production apparatus 22 according to the second embodiment are shown. The gas dissolved water production apparatus 2 used simulates the apparatus of the second embodiment shown in FIG. 2, and the pure water and the experimental apparatus used are as follows.

[Pure water] Specific resistance 18MΩ · cm
[Flow rate of pure water] 0.2L / min
[Gas to be dissolved] Carbon dioxide gas [Flow rate of carbon dioxide gas] 0.08 mL / min (at 20 ° C. and 1 atm)
[Supply pressure of carbon dioxide gas] 0.15 MPa
[Water temperature] 20 ℃
[Specific Resistance Measuring Device] HE-480R (Horiba Advanced Techno Co., Ltd.))
[Gas dissolution chamber] Capacity 20 mL, made of PVC (Example 3)

In the apparatus of the second embodiment, the pure water inflow pipe 23 is a straight pipe having an inner diameter of φ2.5 mm, the pure water outflow pipe 24 has an inner diameter of φ10 mm, and the gas supply pipe 25 has an inner diameter of φ0.13 mm.
The distance M ₁ between the tip of the pure water inflow pipe 23 and the gas supply pipe 25 was 3 (mm).
The Reynolds number R ₅₂ in the pure water outflow pipe 24 was 420. The Reynolds number R ₅₁ in the pure water inflow pipe 23 was 1700.
A gas dissolution chamber 6 was installed downstream of the pure water outflow pipe 24.
The specific resistance value of the carbon dioxide-dissolved water flowing out from the outlet 6b of the gas dissolution chamber 6 was measured and shown in FIG.
In addition, when a part of the pure water outflow pipe 24 was made of glass and the inside was observed, it was confirmed that the microbubbles flowed through the central portion of the pipe and gradually disappeared.

(Comparative Example 4)
Except that the distance M ₂ tip and the gas supply pipe 25 of the pure water inlet pipe 23 and 10 (mm), were the same as in Example 2.
The specific resistance value of the carbon dioxide-dissolved water flowing out from the outlet 6b of the gas dissolution chamber 6 was measured and shown in FIG. 8 Note that a part of the pure water outlet pipe 24 was made of glass and the inside was observed. However, it was confirmed that the giant bubbles generally flowed in the pipe, and a part of the bubbles contacted the inner wall surface of the pipe and adhered to the wall surface.

  The experimental conditions of Examples 1 and 2 and Comparative Examples 1 to 3 are shown in Table 1, and the experimental conditions of Example 3 and Comparative Example 4 are shown in Table 2.

M: distance (mm) between the tip of the gas supply pipe 25 and the tip of the pure water inflow pipe 23, 11 ... a gas dissolved water production apparatus, 12 ... a T-type joint, 12a ... a straight pipe part, 12b ... a branch pipe part, 13 ... Pure water inflow pipe, 14 ... pure water outflow pipe, 14a ... first pure water outflow pipe, 14b ... taper pipe, 14c ... second pure water outflow pipe, 5 ... gas supply pipe,
DESCRIPTION OF SYMBOLS 21 ... Gas dissolved water manufacturing apparatus, 22 ... T-type coupling, 22a ... Straight pipe part, 22b ... Branch pipe part, 23 ... Pure water inflow pipe, 24 ... Pure water outflow pipe, 25 ... Gas supply pipe, 6 ... Gas dissolution Chamber, 6a ... inlet, 6b ... outlet, 7 ... specific resistance measuring device

Claims (8)

In a gas-dissolved water production apparatus for producing gas-dissolved water in which gas is injected into a pure water inflow pipe for supplying pure water and the gas dissolves at a constant concentration,
A T-shaped conduit;
A gas supply pipe which is inserted from one receiving port of the T-shaped pipe line to the position of the center of the T-shaped coupling part and whose base is sealed;
A pure water inflow pipe for supplying pure water perpendicularly to a direction in which the gas is supplied from another one of the T-shaped pipes;
Connected to the downstream of the first pure water outflow pipe and the first pure water outflow pipe, which are connected to one receiving port of the T-shaped pipe line that has neither the gas supply pipe nor the pure water inflow pipe. A pure water outflow pipe comprising a second pure water outflow pipe,
A gas-dissolved water production apparatus comprising: The gas-dissolved water production apparatus according to claim 1, wherein the pure water supply flow rate is 0.1 to 2 L / min.   The apparatus for producing dissolved gas according to claim 1 or 2, wherein a pure water flow in a part or all of the flow path after the gas and the pure water are mixed is a laminar flow.   The gas dissolved water production apparatus according to any one of claims 1 to 3, wherein the diameter of the second pure water outflow pipe is larger than the diameter of the first pure water outflow pipe.   5. The gas dissolved water production apparatus according to claim 1, wherein a Reynolds number in the pure water outflow pipe or the second pure water outflow pipe is less than 2300. 6.   The Reynolds number in the pure water inflow pipe is 2300 or more, or 2 times or more of the Reynolds number of the second pure water outflow pipe or the pure water outflow pipe. The gas-dissolved water production apparatus according to item 1.   The gas-dissolved water production apparatus according to any one of claims 1 to 6, wherein the pure water inflow pipe is inserted to the center of the coupling portion of the T-shaped pipe and the base is sealed. A T-shaped conduit;
A gas supply pipe which is inserted from one receiving port of the T-shaped pipe line to the position of the center of the T-shaped coupling part and whose base is sealed;
A pure water inflow pipe for supplying pure water perpendicularly to a direction in which the gas is supplied from another one of the T-shaped pipes;
Connected to the downstream of the first pure water outflow pipe and the first pure water outflow pipe, which are connected to one receiving port of the T-type pipe that is not provided with either the gas supply pipe or the pure water inflow pipe. A method for producing gas-dissolved water by a gas-dissolved water production apparatus comprising a pure water outflow pipe comprising a second pure water outflow pipe,
A method for producing gas-dissolved water, wherein a pure water flow in a part or all of the flow path after the gas and the pure water are mixed is a laminar flow.

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