Resistivity adjustment device and resistivity adjustment method

Abstract

Using a simple configuration, the present invention suppresses fluctuation in the specific resistance value of a specific resistance value adjustment fluid even when the flow of the supplied fluid fluctuates. More specifically, this specific resistance value adjustment device is equipped with: a hollow fiber membrane module 2 which is partitioned by a hollow fiber membrane 21 into a liquid phase-side region LA to which a liquid L to be subjected to a specific resistance value adjustment is supplied, and a gas phase-side region GA to which an adjustment gas G for adjusting the specific resistance value of the liquid L is supplied; a liquid supply pipe 3; a liquid discharge pipe 4; a module pass-through pipe 7 which passes through the hollow fiber membrane module 2 and is connected to the liquid phase-side region LA of the hollow fiber membrane module 2, the liquid supply pipe 3 and the liquid discharge pipe 4; and a bypass pipe 8 which bypasses the hollow fiber membrane module 2 and is connected to the liquid supply pipe 3 and the liquid discharge pipe 4. Therein, the bypass pipe 8 has a laminarization unit 8A comprising a plurality of small tubes 8C which are narrower than is the module pass-through pipe 7.

Description

[Technical field]

[0001] One aspect of the present invention relates to a resistivity adjusting device and a resistivity adjusting method for adjusting the resistivity of a liquid. [Background technology]

[0002] In the manufacturing process of semiconductors or liquid crystals, ultrapure water is used to clean substrates. In this case, if the resistivity of ultrapure water is high, static electricity is generated. This causes insulation breakdown or re-adhesion of fine particles, which has a significant adverse effect on product yield. To solve such problems, a method using a hydrophobic hollow fiber membrane module has been proposed. In this method, a gas such as carbon dioxide gas or ammonia gas is dissolved in ultrapure water using a hollow fiber membrane module. Then, ions are generated due to dissociation equilibrium, and the generated ions reduce the resistivity of the ultrapure water.

[0003] Furthermore, in processes such as cleaning and dicing of substrates, the flow of ultrapure water fluctuates greatly. Therefore, Patent Document 1 proposes a technique for stabilizing the resistivity even if the flow rate fluctuates. In the technique described in Patent Document 1, a hollow fiber membrane module that generates a small flow rate of gas-added ultrapure water and a bypass pipe through which a large flow rate of ultrapure water passes are provided. The generated gas-added ultrapure water and the ultrapure water that has passed through the bypass pipe are then merged. This makes it possible to easily adjust the resistivity of the ultrapure water.

[0004] However, in the technology described in Patent Document 1, when the flow rate of ultrapure water becomes low, the flow rate of ultrapure water supplied to the hollow fiber membrane module decreases relative to the flow rate of ultrapure water bypassing the hollow fiber membrane module, and the resistivity value of the ultrapure water may increase. Therefore, the technology in Patent Document 2 proposes a technology in which multiple bypass pipes are provided and shutoff valves are provided in one or multiple bypass pipes. In the technology described in Patent Document 2, when the flow rate of ultrapure water decreases, some or all of the shutoff valves are closed. This suppresses a decrease in the flow rate of ultrapure water supplied to the hollow fiber membrane module relative to the flow rate of ultrapure water bypassing the hollow fiber membrane module when the flow rate of ultrapure water becomes low. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 3951385 [Patent Document 2] JP 2012-223725 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the technology described in Patent Document 2 requires the opening and closing of shutoff valves attached to multiple bypass pipes to be controlled according to the flow rate of ultrapure water, which causes problems such as a complex device and high costs.In addition, the technology described in Patent Document 2 also has the problem that when the flow rate of the supplied water changes, the pressure loss in the bypass pipes changes suddenly as the shutoff valves open and close.

[0007] Therefore, one aspect of the present invention aims to provide a resistivity adjustment device and a resistivity adjustment method that have a simple configuration and can suppress fluctuations in the resistivity of the resistivity adjustment liquid even when the flow rate of the liquid supplied fluctuates. [Means for solving the problem]

[0008] The present inventors have conducted extensive research into the above problem and have found that in conventional resistivity adjusting devices, the liquid in the bypass pipe is turbulent, and that this turbulence in the bypass pipe significantly affects the fluctuation in the resistivity of the resistivity-adjusted liquid when the liquid supplied to the resistivity adjusting device fluctuates. This is not limited to the case where ultrapure water is supplied as the liquid, but is also true in the case where various liquids other than ultrapure water are supplied. The resistivity-adjusted liquid refers to a liquid whose resistivity has been adjusted by the resistivity adjusting device.

[0009] More specifically, the pressure loss of the liquid in the bypass pipe where the liquid is turbulent is exponentially related to the flow rate of the liquid. On the other hand, the flow rate of the liquid supplied to the module via pipe that passes through the hollow fiber membrane module is smaller than the flow rate of the liquid supplied to the bypass pipe that bypasses the hollow fiber membrane module. Therefore, compared with the pressure loss of the liquid in the bypass pipe, the pressure loss of the liquid in the module via pipe and the hollow fiber membrane module can be considered to be proportional to the flow rate of the liquid, regardless of whether the liquid flowing through the module via pipe and the hollow fiber membrane module is turbulent or not. In other words, the pressure loss tendency of the liquid in the bypass pipe is significantly different from that of the liquid in the module via pipe and the hollow fiber membrane module.

[0010] Therefore, with the fluctuation in the flow rate of the liquid supplied to the resistivity adjusting device, the distribution ratio of the liquid between the module via pipe and the bypass pipe fluctuates (disrupts), and the resistivity of the resistivity adjusting liquid fluctuates. In particular, when the flow rate of the liquid supplied to the resistivity adjusting device becomes small, the distribution ratio of the liquid in the bypass pipe to the module via pipe becomes large, and the resistivity of the resistivity adjusting liquid becomes high.

[0011] Therefore, the present inventors have attempted to solve the above problem by making the tendency of the pressure loss of the liquid in the bypass pipe closer to the tendency of the pressure loss of the liquid in the module via pipe and the hollow fiber membrane module.

[0012] That is, a resistivity adjustment device according to one aspect of the present invention comprises a hollow fiber membrane module divided by a hollow fiber membrane into a liquid phase side region to which a liquid to be subjected to resistivity adjustment is supplied and a gas phase side region to which an adjustment gas for adjusting the resistivity of the liquid is supplied, a liquid supply pipe, a liquid discharge pipe, a module via pipe which is connected to the liquid phase side region of the hollow fiber membrane module, the liquid supply pipe, and the liquid discharge pipe and passes through the hollow fiber membrane module, and a bypass pipe which is connected to the liquid supply pipe and the liquid discharge pipe and bypasses the hollow fiber membrane module, and the bypass pipe has a laminarization section composed of a plurality of capillaries which are thinner than the module via pipe.

[0013] In this resistivity adjusting device, liquid is supplied to the liquid supply pipe, and an adjusting gas is supplied to the gas phase side region of the hollow fiber membrane module. The liquid supplied to the liquid supply pipe is distributed to the module via pipe and the bypass pipe, and the liquid distributed to the module via pipe is supplied to the liquid phase side region of the hollow fiber membrane module. In the hollow fiber membrane module, the adjusting gas that has permeated the hollow fiber membrane is dissolved in the liquid supplied to the liquid phase side region, and an adjusting gas-added liquid in which the adjusting gas is dissolved in the liquid is generated. The adjusting gas-added liquid generated in the hollow fiber membrane module and the liquid that has bypassed the hollow fiber membrane module join together in the liquid discharge pipe to become a resistivity adjusting liquid, which is discharged from the resistivity adjusting device.

[0014] Since the bypass pipe has a laminarization section composed of a plurality of thin tubes thinner than the module via pipe, the flow of the liquid in the bypass pipe can be made laminar. In laminar flow, the pressure loss of the liquid is proportional to the flow rate of the liquid. Even if the flow is not laminar, the closer the flow rate of the liquid is to laminar flow from turbulent flow. On the other hand, the flow rate of the liquid supplied to the module via pipe is smaller than the flow rate of the liquid supplied to the bypass pipe. Therefore, compared with the pressure loss of the liquid in the bypass pipe, the pressure loss of the liquid in the module via pipe and the hollow fiber membrane module can be considered to be proportional to the flow rate of the liquid, regardless of whether the liquid flowing through the module via pipe and the hollow fiber membrane module is turbulent or not. In other words, the tendency of the pressure loss of the liquid in the bypass pipe is close to the tendency of the pressure loss of the liquid in the module via pipe and the hollow fiber membrane module. Therefore, even if the flow rate of the liquid supplied to the resistivity adjustment device fluctuates, the distribution ratio of the liquid between the module via pipe and the bypass pipe can be suppressed from fluctuating, and the fluctuation of the resistivity of the resistivity adjustment liquid can be suppressed. In particular, even if the flow rate of the liquid supplied to the resistivity adjustment device is small, the distribution ratio of the liquid in the bypass pipe to the module via pipe can be suppressed from increasing, so that the resistivity of the resistivity adjustment liquid can be suppressed from increasing. This makes it possible, with a simple configuration, to suppress fluctuations in the resistivity of the resistivity adjustment liquid even if the flow rate of the supplied liquid fluctuates.

[0015] In one embodiment, the laminarization section may be set so that when ultrapure water is supplied to the bypass pipe as the liquid at a specified flow rate, the liquid becomes laminar in the laminarization section. In this resistivity adjustment device, the laminarization section is set so that when ultrapure water is supplied to the bypass pipe as the liquid at a specified flow rate, the liquid becomes laminar in the laminarization section, which makes it possible to easily design the laminarization section and further suppress fluctuations in the resistivity of the resistivity adjustment liquid even when the flow rate of the supplied liquid fluctuates.

[0016] As one embodiment, the laminarization unit may be set so that when ultrapure water is supplied as a liquid to the bypass pipe at a specified flow rate, the Reynolds number in the laminarization unit is equal to or less than 2300. In this resistivity adjustment device, the laminarization unit is set so that when ultrapure water is supplied as a liquid to the bypass pipe at a specified flow rate, the Reynolds number in the laminarization unit is equal to or less than 2300, which makes it possible to easily design the laminarization unit and further suppress fluctuations in the resistivity of the resistivity adjustment liquid even when the flow rate of the supplied liquid fluctuates.

[0017] In one embodiment, the number of the plurality of capillaries may be equal to or greater than 5. In this resistivity adjusting device, by having the number of the plurality of capillaries be equal to or greater than 5, it becomes easier to laminarize the flow of the liquid in the laminarization section while ensuring the flow rate of the liquid in the laminarization section.

[0018] In one embodiment, the inner diameter of each of the plurality of capillaries may be 0.01 mm or more and 10 mm or less. In this resistivity adjusting device, since the inner diameter of each of the plurality of capillaries is 0.01 mm or more and 10 mm or less, the pressure loss of the liquid in the laminarization section is prevented from becoming too large or too small, and the flow of the liquid in the laminarization section is easily laminarized.

[0019] In one embodiment, the length of each of the plurality of capillaries may be 1 mm or more and 1000 mm or less. In this resistivity adjusting device, by having the length of each of the plurality of capillaries be 1 mm or more and 1000 mm or less, it is possible to suppress the pressure loss of the liquid in the laminar flow section from becoming too large or too small.

[0020] In one embodiment, the length of the laminarization section may be 1% or more of the length of the bypass pipe. In this resistivity adjusting device, the length of the laminarization section is 1% or more of the length of the bypass pipe, so that the flow of the liquid in the bypass pipe can be easily laminarized.

[0021] In one embodiment, the resistivity adjusting device may further include a branching module connected to the liquid supply pipe, the module via pipe, and the bypass pipe to communicate with the liquid supply pipe, the module via pipe, and the bypass pipe, and a junction module connected to the liquid discharge pipe, the module via pipe, and the bypass pipe to communicate with the liquid discharge pipe, the module via pipe, and the bypass pipe, and the laminarization section may extend from the branching module to the junction module. In this resistivity adjusting device, by providing the branching module and the junction module, a branching structure from the liquid supply pipe to the module via pipe and the bypass pipe, and a junction structure from the module via pipe and the bypass pipe to the liquid discharge pipe can be easily realized. In particular, since the bypass pipe has a laminarization section composed of a plurality of thin tubes, the bypass pipe can be easily connected to the liquid supply pipe and the liquid discharge pipe through the branching module and the junction module. Moreover, since the laminarization section extends from the branching module to the junction module, the laminarization section can be easily formed, and the flow of the liquid in the laminarization section can be easily laminarized.

[0022] As an embodiment, the resistivity adjusting device may further include a gas supply pipe connected to the gas phase region for supplying the adjusting gas to the gas phase region, and a gas exhaust pipe connected to the gas phase region for exhausting the adjusting gas from the gas phase region. By providing the gas supply pipe and the gas exhaust pipe, the resistivity adjusting device can easily supply and exhaust the adjusting gas to and from the gas phase region of the hollow fiber membrane module.

[0023] In one embodiment, the resistivity adjusting device may further include a valve attached to the module via pipe for adjusting the liquid distribution ratio between the module via pipe and the bypass pipe. By providing the valve, the resistivity adjusting device can easily adjust the flow distribution ratio of the liquid between the module via pipe and the bypass pipe. Moreover, since the valve is attached to the module via pipe, it is possible to suppress the valve from hindering laminar flow in the bypass pipe.

[0024] A resistivity adjustment device according to one aspect of the present invention adjusts the resistivity of a liquid by supplying a liquid to a liquid supply pipe of any of the resistivity adjustment devices described above and supplying an adjustment gas to the gas phase side region of a hollow fiber membrane module.

[0025] In this resistivity adjustment method, in the resistivity adjustment device, the resistivity of the liquid is adjusted by supplying the liquid to the liquid supply pipe and supplying an adjustment gas to the gas phase region of the hollow fiber membrane module, thereby making it possible to suppress fluctuations in the resistivity of the resistivity adjustment liquid even when the flow rate of the supplied liquid fluctuates, with a simple configuration. Effect of the Invention

[0026] According to one aspect of the present invention, it is possible to suppress fluctuations in the resistivity of the resistivity adjusting liquid even when the flow rate of the supplied liquid fluctuates, with a simple configuration. [Brief description of the drawings]

[0027] [Figure 1] 1 is a schematic diagram of a resistivity adjusting device according to an embodiment; [Diagram 2] FIG. 2 is an enlarged cross-sectional view of a portion of the hollow fiber membrane. [Diagram 3] 2 is a cross-sectional view showing a part of the resistivity adjusting device shown in FIG. [Figure 4] FIG. 4 is an enlarged cross-sectional view of a portion of the bypass pipe. [Diagram 5]4 is a graph showing the measurement results of the resistivity of the resistivity adjusting liquid in Example 1. [Figure 6] 1 is a graph showing the measurement results of the resistivity of a resistivity adjusting liquid in Comparative Example 1. [Figure 7] 13 is a graph showing the measurement results of the pressure loss of the liquid in the module via pipe and the bypass pipe in Comparative Example 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, a resistivity adjusting device and a resistivity adjusting method according to an embodiment will be described in detail with reference to the drawings. In addition, in all the drawings, the same or corresponding parts are given the same reference numerals, and duplicated explanations will be omitted.

[0029] FIG. 1 is a schematic diagram of a resistivity adjusting device of an embodiment. As shown in FIG. 1, the resistivity adjusting device 1 of this embodiment generates an adjustment gas added liquid L1 by dissolving an adjustment gas G in a liquid L. The resistivity adjusting device 1 is a device that generates a resistivity adjusted liquid L2 by adjusting the resistivity of the liquid L by merging the liquid L and the adjustment gas added liquid L1. The adjustment gas added liquid L1 is the liquid L in which the adjustment gas G is dissolved, and the resistivity adjusted liquid L2 is the liquid L in which the resistivity is adjusted. For this reason, the adjustment gas added liquid L1 and the resistivity adjusted liquid L2 may be simply referred to as liquid L. The resistivity adjusting device 1 includes a hollow fiber membrane module 2, a liquid supply pipe 3, a liquid discharge pipe 4, a gas supply pipe 5, a gas discharge pipe 6, a module via pipe 7, a bypass pipe 8, a valve 9, a branching module 11, and a merging module 12.

[0030] The hollow fiber membrane module 2 is a module for dissolving an adjusting gas G for adjusting the resistivity in a liquid L for adjusting the resistivity. The hollow fiber membrane module 2 includes a plurality of hollow fiber membranes 21 and a housing 22 for accommodating these hollow fiber membranes 21 therein.

[0031] Liquid L is a liquid whose resistivity is to be adjusted. The liquid used as Liquid L is not particularly limited, but may be, for example, pure water or ultrapure water for cleaning semiconductors, liquid crystals, etc. Usually, the resistivity of pure water and ultrapure water is 0.1 MΩ·cm or more. Therefore, the resistivity of Liquid L may be, for example, 0.1 MΩ·cm or more, preferably 15.0 MΩ·cm or more, and more preferably 17.5 MΩ·cm or more. In addition, the upper limit of the resistivity of Liquid L is not particularly limited, but may be, for example, 18.248 MΩ·cm or less.

[0032] The temperature of Liquid L is not particularly limited, but may be, for example, in the range of 5° C. or more, preferably 10° C. or more, more preferably 20° C. or more, and may be, for example, in the range of 60° C. or less, preferably 40° C. or less, more preferably 30° C. or less. The supply pressure of Liquid L is not particularly limited, but may be, for example, in the range of 0.01 MPa or more, preferably 0.1 MPa or more, more preferably 0.2 PMa or more, and may be, for example, in the range of 1.0 MPa or less, preferably 0.4 MPa or less, more preferably 0.3 MPa or less.

[0033] The adjustment gas G is a gas for adjusting the resistivity of the liquid L. The gas used as the adjustment gas G is not particularly limited, but may be, for example, carbon dioxide gas or ammonia gas. The temperature of the adjustment gas G is not particularly limited, but may be, for example, 0°C or higher, preferably 20°C or higher, more preferably 25°C or higher, and may be, for example, 60°C or lower, preferably 50°C or lower, more preferably 30°C or lower. The supply pressure of the adjustment gas G is not particularly limited, but may be, for example, 0.01 MPa or higher, preferably 0.05 MPa or higher, and may be, for example, 0.5 MPa or lower, preferably 0.2 MPa or lower, more preferably 0.15 MPa or lower.

[0034] The hollow fiber membrane 21 is a hollow fiber-shaped membrane that allows gas to permeate but not liquid to permeate. There are no particular limitations on the material, membrane shape, membrane form, etc. of the hollow fiber membrane 21. The housing 22 is an airtight container that houses the hollow fiber membrane 21 inside. The membrane area of ​​the hollow fiber membrane module 2 can be appropriately adjusted depending on the treatment flow rate (flow rate of liquid L) and is not particularly limited, and may be, for example, 0.1 m 2 More than 120m 2 When the optimum value of the membrane area of ​​the hollow fiber membrane module 2 is adjusted according to the treatment flow rate, for example, in the case of a general flow rate treatment (e.g., 1 to 120 L / min), it may be 0.1 m 2 More than 4.0m 2 or less, and for larger flow rate treatment (e.g., 120 to 4000 L / min), 4.0 m 2 More than 120m 2 It may be in the following range:

[0035] The hollow fiber membrane module 2 includes a plurality of hollow fiber membranes 21 and a housing 22 that houses these hollow fiber membranes 21 inside. The hollow fiber membrane module 2 includes a plurality of hollow fiber membranes 21 and a housing 22 that houses these hollow fiber membranes 21 inside.

[0036] FIG. 2 is a cross-sectional view of an enlarged portion of the hollow fiber membrane. As shown in FIG. 2, the hollow fiber membrane module 2 is divided into a liquid phase side area LA and a gas phase side area GA by the hollow fiber membrane 21. The liquid phase side area LA is an area in the hollow fiber membrane module 2 to which a liquid L for adjusting the resistivity is supplied. The gas phase side area GA is an area in the hollow fiber membrane module 2 to which an adjustment gas G for adjusting the resistivity is supplied. The types of hollow fiber membrane module 2 include an internal perfusion type and an external perfusion type. In this embodiment, either an internal perfusion type or an external perfusion type may be used. In the external perfusion type hollow fiber membrane module 2, the inside (inner surface side) of the hollow fiber membrane 21 is the gas phase side area GA, and the outside (outer surface side) of the hollow fiber membrane 21 is the liquid phase side area LA. In the internal perfusion type hollow fiber membrane module 2, the inside (inner surface side) of the hollow fiber membrane 21 is the liquid phase side area LA, and the outside (outer surface side) of the hollow fiber membrane 21 is the gas phase side area GA. In the hollow fiber membrane module 2, the adjustment gas G supplied to the gas phase side area GA and permeating the hollow fiber membrane 21 is dissolved in the liquid L supplied to the liquid phase side area LA, thereby generating the adjustment gas-added liquid L1.

[0037] As shown in FIG. 1, the housing 22 is formed with a liquid supply port 22A, a liquid discharge port 22B, a gas supply port 22C, and a gas discharge port 22D. The liquid supply port 22A is an opening formed in the housing 22 to supply the liquid L to the liquid phase side area LA. The liquid discharge port 22B is an opening formed in the housing 22 to discharge the adjustment gas added liquid L1 from the liquid phase side area LA. The gas supply port 22C is an opening formed in the housing 22 to supply the adjustment gas G to the gas phase side area GA. The gas discharge port 22D is an opening formed in the housing 22 to discharge the adjustment gas G from the gas phase side area GA. For this reason, the liquid supply port 22A and the liquid discharge port 22B are communicated with the liquid phase side area LA. In addition, the gas supply port 22C and the gas discharge port 22D are communicated with the gas phase side area GA. The positions of liquid supply port 22A, liquid exhaust port 22B, gas supply port 22C, and gas exhaust port 22D in housing 22 are not particularly limited.

[0038] Fig. 3 is a cross-sectional view showing a part of the resistivity adjusting device shown in Fig. 1. As shown in Figs. 1 and 3, the liquid supply pipe 3 is a tubular member having a flow path 3A for the liquid L formed therein. The liquid L is supplied to the liquid supply pipe 3. The material, characteristics (hardness, elasticity, etc.), shape, dimensions, etc. of the liquid supply pipe 3 are not particularly limited.

[0039] The liquid discharge pipe 4 is a tubular member in which a flow path 4A for the resistivity adjustment liquid L2 is formed. The resistivity adjustment liquid L2 is discharged from the liquid discharge pipe 4. The material, characteristics (hardness, elasticity, etc.), shape, dimensions, etc. of the liquid discharge pipe 4 are not particularly limited.

[0040] The gas supply pipe 5 is a tubular member having a flow path (not shown) formed therein for the adjustment gas G. The gas supply pipe 5 is connected to the gas supply port 22C and communicates with the gas phase area GA of the hollow fiber membrane module 2 in order to supply the adjustment gas G to the gas phase area GA of the hollow fiber membrane module 2. The material, characteristics (hardness, elasticity, etc.), shape, dimensions, etc. of the gas supply pipe 5 are not particularly limited.

[0041] The gas exhaust pipe 6 is a tubular member having a flow path (not shown) for the adjustment gas G formed therein. The gas exhaust pipe 6 is connected to the gas outlet 22D and communicates with the gas phase area GA of the hollow fiber membrane module 2 in order to exhaust the adjustment gas G from the gas phase area GA of the hollow fiber membrane module 2. The gas exhaust pipe 6 is fitted with a valve 6A for opening and closing the flow path of the gas exhaust pipe 6. In the gas exhaust pipe 6, the adjustment gas G and the like can be exhausted from the gas phase area GA of the hollow fiber membrane module 2 by opening the valve 6A. In addition, in the gas exhaust pipe 6, the adjustment gas G and the like can be prevented from being exhausted from the gas phase area GA of the hollow fiber membrane module 2 by closing the valve 6A. The valve 6A may be capable of adjusting the opening degree of the flow path of the gas exhaust pipe 6. The material, characteristics (hardness, elasticity, etc.), shape, dimensions, etc. of the gas exhaust pipe 6 are not particularly limited. The gas exhaust pipe 6 may be provided with a leakage portion (not shown) that allows the regulated gas G to leak out from the gas phase side area GA of the hollow fiber membrane module 2. The regulated gas G constantly leaks out from the leakage portion.

[0042] The module via pipe 7 is connected to the liquid phase area LA, the liquid supply pipe 3, and the liquid discharge pipe 4 of the hollow fiber membrane module 2, and passes through the hollow fiber membrane module 2. In other words, the hollow fiber membrane module 2 is disposed midway through the module via pipe 7. The module via pipe 7 has an upstream module via pipe 71 and a downstream module via pipe 72. The upstream module via pipe 71 is disposed upstream of the hollow fiber membrane module 2 in the flow direction of the liquid L. The downstream module via pipe 72 is disposed downstream of the hollow fiber membrane module 2 in the flow direction of the liquid L.

[0043] The upstream module via pipe 71 is a tubular member having a flow path 71A formed therein. The upstream module via pipe 71 is connected to the liquid supply pipe 3 and the liquid phase area LA of the hollow fiber membrane module 2 in order to supply the liquid L supplied to the liquid supply pipe 3 to the liquid phase area LA of the hollow fiber membrane module 2. The upstream end of the upstream module via pipe 71 is connected to the branch module 11 in order to be connected to the flow path 3A of the liquid supply pipe 3. The downstream end of the upstream module via pipe 71 is connected to the liquid supply port 22A in order to be connected to the liquid phase area LA of the hollow fiber membrane module 2. The material, characteristics (hardness, elasticity, etc.), shape, dimensions, etc. of the upstream module via pipe 71 are not particularly limited. However, it is preferable that the cross-sectional area of ​​the flow path 71A of the upstream module via pipe 71 is smaller than the cross-sectional area of ​​the flow path 3A of the liquid supply pipe 3.

[0044] The downstream module via pipe 72 is a tubular member having a flow path 72A formed therein. The downstream module via pipe 72 is connected to the liquid discharge pipe 4 and the liquid phase side area LA of the hollow fiber membrane module 2 in order to discharge the adjustment gas-added liquid L1 generated in the hollow fiber membrane module 2 to the liquid discharge pipe 4. The upstream end of the downstream module via pipe 72 is connected to the liquid discharge port 22B in order to be connected to the liquid phase side area LA of the hollow fiber membrane module 2. The downstream end of the downstream module via pipe 72 is connected to the merging module 12 in order to be connected to the flow path 4A of the liquid discharge pipe 4. The material, characteristics (hardness, elasticity, etc.), shape, dimensions, etc. of the downstream module via pipe 72 are not particularly limited. However, it is preferable that the cross-sectional area of ​​the flow path 72A of the downstream module via pipe 72 is smaller than the cross-sectional area of ​​the flow path 4A of the liquid discharge pipe 4.

[0045] FIG. 4 is a cross-sectional view of an enlarged portion of the bypass pipe. As shown in FIGS. 1, 3, and 4, the bypass pipe 8 is connected to the liquid supply pipe 3 and the liquid discharge pipe 4 to bypass the hollow fiber membrane module 2. In other words, the bypass pipe 8 is not connected to the hollow fiber membrane module 2, and discharges the liquid L supplied to the liquid supply pipe 3 to the liquid discharge pipe 4 without passing through the hollow fiber membrane module 2. The direction of the bypass pipe 8 from the liquid supply pipe 3 to the liquid discharge pipe 4 is referred to as the flow direction FD from the liquid supply pipe 3 to the liquid discharge pipe 4. The flow direction FD from the liquid supply pipe 3 to the liquid discharge pipe 4 is also simply referred to as the flow direction FD. The upstream end of the bypass pipe 8 (the upstream side in the flow direction FD) is connected to the branch module 11 to communicate with the liquid supply pipe 3. The downstream end of the bypass pipe 8 (the downstream side in the flow direction FD) is connected to the merging module 12 to communicate with the liquid discharge pipe 4. The bypass pipe 8 is not provided with a valve such as a shutoff valve for opening and closing the bypass pipe 8.

[0046] The bypass pipe 8 has a laminar flow section 8A and a bypass housing 8B that houses the laminar flow section 8A.

[0047] The bypass housing 8B is formed in a cylindrical shape so as to be able to accommodate the laminarization section 8A. An upstream end (upstream side in the flow direction FD) of the bypass housing 8B is airtightly connected to the branching module 11. An downstream end (downstream side in the flow direction FD) of the bypass housing 8B is airtightly connected to the merging module 12. That is, the laminarization section 8A extends from the branching module 11 to the merging module 12. The bypass housing 8B can be airtightly connected to the branching module 11 and the merging module 12 by, for example, adhesion, fusion, fitting, or a combination of these. The material, characteristics (hardness, elasticity, etc.), shape, dimensions, etc. of the bypass housing 8B are not particularly limited. However, the bypass housing 8B is preferably a straight-extending cylindrical shape.

[0048] The laminarization section 8A is composed of a plurality of thin tubes 8C in order to laminarize the flow of the liquid L in the bypass pipe 8. Laminarization does not only mean to make a flow laminar, but also means to make a turbulent flow closer to a laminar flow. A laminar flow is, for example, a flow with a Reynolds number of 2300 or less. Making a turbulent flow closer to a laminar flow means, for example, lowering the Reynolds number to 2300. The laminarization section 8A may be set so that the liquid L becomes a laminar flow in the laminarization section 8A when ultrapure water is supplied to the bypass pipe 8 at a specified flow rate as the liquid L. The laminarization section 8A may be set so that the Reynolds number in the laminarization section 8A becomes 2300 or less, preferably 2000 or less, more preferably 500 or less, when ultrapure water is supplied to the bypass pipe 8 at a specified flow rate as the liquid L. These specified flow rates can be any value, for example, between 0.1 L / min and 120 L / min.

[0049] Each of the multiple capillaries 8C is a tubular member having a flow path 8D formed therein. Each of the multiple capillaries 8C is thinner than the module via pipe 7 (the upstream module via pipe 71 and the downstream module via pipe 72). That is, the cross-sectional area of ​​the flow path 8D of each of the multiple capillaries 8C is smaller than the cross-sectional area of ​​the flow path 71A of the upstream module via pipe 71 and the cross-sectional area of ​​the flow path 72A of the downstream module via pipe 72. The sum of the cross-sectional areas of the respective flow paths 8D of the multiple capillaries 8C is larger than, for example, the cross-sectional areas of the flow path 71A of the upstream module via pipe 71 and the flow path 72A of the downstream module via pipe 72. Each of the multiple capillaries 8C is formed, for example, from polymethylpentene (PMP), polypropylene (PP), polyethylene (PE), urethane, polytetrafluoroethylene (PFA), nylon, or the like.

[0050] The upstream ends of the multiple capillaries 8C are fixed to the bypass housing 8B or the branching module 11 by a first sealing portion 8E. The downstream ends of the multiple capillaries 8C are fixed to the bypass housing 8B or the merging module 12 by a second sealing portion 8G. The multiple capillaries 8C extend from the branching module 11 to the merging module 12. The lengths of the laminarization section 8A and the multiple capillaries 8C are the lengths in the flow direction FD.

[0051] The first sealing portion 8E seals between the multiple capillaries 8C and the bypass housing 8B or the branching module 11 at which the multiple capillaries 8C are fixed, so as not to block the flow paths 8D of the multiple capillaries 8C. That is, the first sealing portion 8E is filled between the multiple capillaries 8C and between the multiple capillaries 8C and the bypass housing 8B or the branching module 11 at which the multiple capillaries 8C are fixed (see FIG. 4). The flow paths 8D of the multiple capillaries 8C are exposed from the upstream end surface 8F and communicate with the branching module 11. Therefore, the liquid L supplied to the bypass pipe 8 is supplied to the flow paths 8D of the multiple capillaries 8C from the upstream end surface 8F of each of the multiple capillaries 8C. The first sealing portion 8E is formed of, for example, a resin. Examples of the resin used for the first sealing portion 8E include epoxy resin, urethane resin, ultraviolet curing resin, and polyolefin resin such as polyethylene and polypropylene.

[0052] The second sealing portion 8G seals between the multiple capillaries 8C and the bypass housing 8B or the part of the merging module 12 to which the multiple capillaries 8C are fixed so as not to block the flow paths 8D of the multiple capillaries 8C. That is, the second sealing portion 8G is filled between the multiple capillaries 8C and between the multiple capillaries 8C and the bypass housing 8B or the part of the merging module 12 to which the multiple capillaries 8C are fixed (see FIG. 4). The flow paths 8D of the multiple capillaries 8C are exposed from the downstream end surface 8H and communicate with the merging module 12. Therefore, the liquid L supplied to the flow paths 8D of the multiple capillaries 8C is discharged from the downstream end surface 8H of the multiple capillaries 8C. The second sealing portion 8G is formed of, for example, a resin. Examples of the resin used for the second sealing portion 8G include epoxy resin, urethane resin, ultraviolet curing resin, and polyolefin resin such as polyethylene and polypropylene.

[0053] Here, the Reynolds number Re of the liquid L flowing through each of the multiple capillaries 8C can be calculated by the following formula (1). In formula (1), V is the flow velocity (m / s) of the liquid L flowing through each of the multiple capillaries 8C, D is the inner diameter (m) of each of the multiple capillaries 8C, and ν is the kinetic viscosity of the liquid L (m 2 / s) and ρ is the density of liquid L (kg / m 3 ) and μ is the viscosity of liquid L (Pa s).

number

[0054] As shown in formula (1), the Reynolds number Re of the liquid L flowing through each of the multiple capillaries 8C varies depending on the flow velocity V of the liquid L flowing through each of the multiple capillaries 8C, the inner diameter D of each of the multiple capillaries 8C, the kinetic viscosity ν of the liquid L, the density ρ of the liquid L, and the viscosity μ of the liquid L. Therefore, for the multiple capillaries 8C, these parameters may be set so that the Reynolds number of the liquid L in the laminarization section 8A is 2300 or less, preferably 1000 or less, and more preferably 500 or less.

[0055] For example, from the viewpoint of facilitating laminarization of the flow of the liquid L in the laminarization section 8A, the inner diameter (diameter) of each of the plurality of capillaries 8C may be 10 mm or less, preferably 5 mm or less, and more preferably 1 mm or less. On the other hand, from the viewpoint of ease of manufacture of the laminarization section 8A, the inner diameter (diameter) of each of the plurality of capillaries 8C may be 0.01 mm or more, preferably 0.05 mm or more, and more preferably 0.1 mm or more. From these viewpoints, the inner diameter (diameter) of each of the plurality of capillaries 8C may be 0.01 mm or more and 10 mm or less, preferably 0.05 mm or more and 5 mm or less, and more preferably 0.1 mm or more and 1 mm or less.

[0056] Here, when the inner diameter of each of the plurality of capillaries 8C is reduced, the flow rate of the liquid flowing through the laminarization section 8A is reduced. Therefore, from the viewpoint of ensuring the flow rate of the liquid through the laminarization section 8A, the number of the capillaries 8C in the laminarization section 8A may be 5 or more, preferably 50 or more, more preferably 100 or more, and more preferably 500 or more. On the other hand, from the viewpoint of the ease of manufacturing the laminarization section 8A, the number of the capillaries 8C in the laminarization section 8A may be 100,000 or less, preferably 27,000 or less, more preferably 18,000 or less, and more preferably 9,000 or less. From these viewpoints, the number of the capillaries 8C in the laminarization section 8A may be 5 or more and 100,000 or less, preferably 50 or more and 27,000 or less, more preferably 100 or more and 18,000 or less, and more preferably 500 or more and 9,000 or less.

[0057] The pressure loss ΔPa (Pa) of the liquid L in the laminar flow section 8A is calculated by the Hagen-Poiseuille formula (2). In the formula (2), Q is the flow rate (m 2 / s), μ is the viscosity of the liquid L (Pa s), n is the number of the multiple capillaries 8C, D is the inner diameter (m) of each of the multiple capillaries 8C, and L is the length (m) of each of the multiple capillaries 8C.

number

[0058] As shown in formula (2), the pressure loss ΔPa of the liquid L in the laminarization section 8A varies depending on the flow rate Q of the liquid L flowing through the laminarization section 8A, the viscosity μ of the liquid L, the number n of the multiple capillaries 8C, the inner diameter D of each of the multiple capillaries 8C, and the length L of each of the multiple capillaries 8C. Therefore, for the multiple capillaries 8C, these parameters may be set so that the pressure loss of the liquid L in the laminarization section 8A is, for example, 10 kPa or more and 1000 kPa or less.

[0059] For example, from the viewpoint of preventing the pressure loss of the liquid in the laminarization section from becoming excessive, the number of the capillaries 8C in the laminarization section 8A may be 5 or more, preferably 50 or more, more preferably 100 or more, and even more preferably 500 or more. On the other hand, from the viewpoint of ease of manufacture of the laminarization section 8A, the number of the capillaries 8C in the laminarization section 8A may be 100,000 or less, preferably 27,000 or less, more preferably 18,000 or less, and even more preferably 9,000 or less. From these viewpoints, the number of the capillaries 8C in the laminarization section 8A may be 5 or more and 100,000 or less, preferably 50 or more and 27,000 or less, more preferably 100 or more and 18,000 or less, and even more preferably 500 or more and 9,000 or less.

[0060] From the viewpoint of preventing the pressure loss of the liquid in the laminarization section from becoming excessive, each of the plurality of capillaries 8C may have an inner diameter (diameter) of 0.01 mm or more, preferably 0.05 mm or more, and more preferably 0.1 mm or more. On the other hand, from the viewpoint of ease of manufacture of the laminarization section 8A, each of the plurality of capillaries 8C may have an inner diameter (diameter) of 10 mm or less, preferably 5 mm or less, and more preferably 1 mm or less. From these viewpoints, each of the plurality of capillaries 8C may have an inner diameter (diameter) of 0.01 mm or more and 10 mm or less, preferably 0.05 mm or more and 5 mm or less, and more preferably 0.1 mm or more and 1 mm or less.

[0061] From the viewpoint of preventing the pressure loss of the liquid L in the laminarization section from becoming excessive, the length of each of the plurality of capillaries 8C may be 1000 mm or less, preferably 500 mm or less, and more preferably 100 mm or less. On the other hand, from the viewpoint of ease of manufacture of the laminarization section 8A, the length of each of the plurality of capillaries 8C may be 1 mm or more, preferably 5 mm or more, and more preferably 10 mm or more. From these viewpoints, the length of each of the plurality of capillaries 8C may be 1 mm or more and 1000 mm or less, preferably 5 mm or more and 500 mm or less, and more preferably 10 mm or more and 100 mm or less.

[0062] Furthermore, since the laminarization of the liquid L in the bypass pipe 8 is achieved by the laminarization section 8A, the laminarization of the liquid L in the bypass pipe 8 is promoted as the proportion of the laminarization section 8A in the bypass pipe 8 increases. From this viewpoint, the length of the laminarization section 8A may be 1% or more of the length of the bypass pipe 8, preferably 10% or more, and more preferably 50% or more. On the other hand, from the viewpoint of ease of manufacture of the laminarization section 8A, the length of the laminarization section 8A may be 100% or less of the length of the bypass pipe 8, preferably 90% or less, and more preferably 80% or less. From these viewpoints, the length of the laminarization section 8A may be 1% or more and 100% or less, preferably 10% or more and 90% or less, and more preferably 50% or more and 80% or less of the length of the bypass pipe 8.

[0063] The valve 9 is attached to the module via pipe 7 and adjusts the distribution ratio of the liquid L between the module via pipe 7 and the bypass pipe 8. The valve 9 adjusts the distribution ratio of the liquid L between the module via pipe 7 and the bypass pipe 8, for example, so that the flow rate of the liquid L supplied to the module via pipe 7 is (much) smaller than the flow rate of the liquid L supplied to the bypass pipe 8. For example, when generating a resistivity adjustment liquid L2 of 1.0 MΩ·cm, the distribution ratio of the liquid L between the module via pipe 7 and the bypass pipe 8 is about 1:3920 (module via pipe 7 side:bypass pipe 8 side).

[0064] The valve 9 is attached to the upstream module via pipe 71, for example, and adjusts the opening degree of the flow path 71A of the upstream module via pipe 71 to adjust the flow rate of the liquid L flowing through the upstream module via pipe 71. The valve 9 may be attached to the downstream module via pipe 72 and adjusts the opening degree of the flow path 72A of the downstream module via pipe 72 to adjust the flow rate of the adjustment gas-added liquid L1 flowing through the downstream module via pipe 72. Various known valves can be used as the valve 9, and for example, a needle valve may be used.

[0065] The branching module 11 is connected to the liquid supply pipe 3, the upstream module via pipe 71, and the bypass pipe 8, and communicates the liquid supply pipe 3, the upstream module via pipe 71, and the bypass pipe 8. The branching module 11 distributes the liquid L supplied to the liquid supply pipe 3 to the upstream module via pipe 71 and the bypass pipe 8. The branching module 11 has a flow path 11A that communicates with the flow path 3A of the liquid supply pipe 3, the flow path 71A of the upstream module via pipe 71, and each of the flow paths 8D of the multiple capillaries 8C. The flow path 11A is, for example, branched into three branches, and each branch is connected to the flow path 3A of the liquid supply pipe 3, the flow path 71A of the upstream module via pipe 71, and each of the flow paths 8D of the multiple capillaries 8C, respectively.

[0066] The junction module 12 is connected to the liquid discharge pipe 4, the downstream module via pipe 72, and the bypass pipe 8, and communicates the liquid discharge pipe 4, the downstream module via pipe 72, and the bypass pipe 8. The junction module 12 merges the adjustment gas added liquid L1 supplied to the downstream module via pipe 72 and the liquid L supplied to the bypass pipe 8, and discharges the resistivity adjustment liquid L2, which is a mixture of the adjustment gas added liquid L1 and the liquid L, to the liquid discharge pipe 4. The junction module 12 has a flow path 12A that is connected to the flow path 4A of the liquid discharge pipe 4, the flow path 72A of the downstream module via pipe 72, and each of the flow paths 8D of the multiple capillaries 8C. The flow path 12A is, for example, branched into three branches, and each branch is connected to the flow path 4A of the liquid discharge pipe 4, the flow path 72A of the downstream module via pipe 72, and each of the flow paths 8D of the multiple capillaries 8C.

[0067] Next, a method for adjusting the resistivity of the liquid L by the resistivity adjusting device 1 will be described.

[0068] In this method, the liquid L is supplied to the liquid supply pipe 3, and an adjustment gas G is supplied to the gas phase side area GA of the hollow fiber membrane module 2, thereby adjusting the resistivity of the liquid L.

[0069] Specifically, liquid L is supplied to the liquid supply pipe 3, and adjusted gas G is supplied to the gas supply pipe 5. Then, the liquid L supplied to the liquid supply pipe 3 is distributed to the upstream module via pipe 71 and the bypass pipe 8 in the branch module 11. The liquid distributed to the upstream module via pipe 71 is supplied to the liquid phase side area LA of the hollow fiber membrane module 2. On the other hand, the adjusted gas G supplied to the gas supply pipe 5 is supplied to the gas phase side area GA of the hollow fiber membrane module 2. The adjusted gas G supplied to the gas phase side area GA is dissolved in the liquid L supplied to the liquid phase side area LA by permeating the hollow fiber membrane 21. As a result, an adjusted gas-added liquid L1 in which the adjusted gas G is dissolved in the liquid L is generated. At this time, it is preferable to generate an adjusted gas saturated liquid in which the adjusted gas G is dissolved in the liquid L in a saturated state as the adjusted gas-added liquid L1. In other words, it is preferable to adjust the supply pressure of the adjusted gas G and the flow rate of the liquid L distributed to the upstream module via pipe 71 so that the adjusted gas G is dissolved in the liquid L in a saturated state. The saturated state includes not only a completely saturated state but also a state close to the saturated state. The close to the saturated state refers to a state in which the adjustment gas G is dissolved in the liquid L to such an extent that the resistivity value of the liquid L can be adjusted only by the distribution ratio of the liquid L between the upstream module via pipe 71 and the bypass pipe 8.

[0070] Then, the adjustment gas-added liquid L1 is discharged from the liquid phase side area LA of the hollow fiber membrane module 2 to the downstream module via pipe 72. The adjustment gas-added liquid L1 discharged from the liquid phase side area LA of the hollow fiber membrane module 2 to the downstream module via pipe 72 merges with the liquid L distributed to the bypass pipe 8 in the merging module 12. As a result, a resistivity-adjusted liquid L2 with an adjusted resistivity is generated. Then, the generated resistivity-adjusted liquid L2 is discharged from the liquid discharge pipe 4. The adjustment gas G and the like in the gas phase side area GA of the hollow fiber membrane module 2 may be discharged from the gas discharge pipe 6 by opening the valve 6A.

[0071] In this manner, in the resistivity adjusting device 1 of the present embodiment, the bypass pipe 8 has the laminarization section 8A constituted by a plurality of capillaries 8C thinner than the module via pipe 7, so that the flow of the liquid L in the bypass pipe 8 can be made laminar. In laminar flow, the pressure loss of the liquid is proportional to the flow rate of the liquid. Even if the flow is not laminar, the pressure loss of the liquid is closer to being proportional to the flow rate of the liquid as the flow approaches from turbulent flow to laminar flow. On the other hand, the flow rate of the liquid L supplied to the module via pipe 7 is smaller than the flow rate of the liquid L supplied to the bypass pipe 8. Therefore, compared with the pressure loss of the liquid L in the bypass pipe 8, the pressure loss of the liquid L in the module via pipe 7 and the hollow fiber membrane module 2 can be considered to be proportional to the flow rate of the liquid L, regardless of whether the liquid L flowing through the module via pipe 7 and the hollow fiber membrane module 2 is turbulent or not. In other words, the tendency of the pressure loss of the liquid L in the bypass pipe 8 becomes closer to the tendency of the pressure loss of the liquid L in the module via pipe 7 and the hollow fiber membrane module 2. Therefore, even if the flow rate of the liquid L supplied to the resistivity adjusting device 1 varies, it is possible to suppress fluctuations in the distribution ratio of the liquid L between the module via pipe 7 and the bypass pipe 8, and to suppress fluctuations in the resistivity of the resistivity adjusting liquid. In particular, even if the flow rate of the liquid L supplied to the resistivity adjusting device 1 becomes small, it is possible to suppress an increase in the distribution ratio of the liquid L in the bypass pipe 8 to the module via pipe 7, and therefore it is possible to suppress an increase in the resistivity of the resistivity adjusting liquid L2. As a result, with a simple configuration, it is possible to suppress fluctuations in the resistivity of the resistivity adjusting liquid L2 even if the flow rate of the supplied liquid L varies.

[0072] Furthermore, in the resistivity adjustment device 1, the laminarization section 8A is set so that when ultrapure water is supplied to the bypass pipe 8 as the liquid L at a specified flow rate, the liquid L becomes laminar in the laminarization section 8A. This makes it possible to easily design the laminarization section 8A and further suppress fluctuations in the resistivity of the resistivity adjustment liquid L2 even if the flow rate of the supplied liquid L fluctuates.

[0073] Furthermore, in the resistivity adjustment device 1, the laminarization section 8A is set so that when ultrapure water is supplied to the bypass pipe 8 as the liquid L at a specified flow rate, the Reynolds number in the laminarization section 8A is 2300 or less. This makes it possible to easily design the laminarization section 8A and further suppress fluctuations in the resistivity of the resistivity adjustment liquid L2 even if the flow rate of the supplied liquid L fluctuates.

[0074] Furthermore, in the resistivity adjustment device 1, the number of capillaries 8C in the laminarization section 8A is 5 or more, preferably 50 or more, more preferably 100 or more, and even more preferably 500 or more, thereby making it easier to laminarize the flow of liquid in the laminarization section while ensuring the flow rate of the liquid in the laminarization section.

[0075] Furthermore, in the resistivity adjustment device 1, the inner diameter of each of the multiple capillaries 8C is 0.01 mm or more and 10 mm or less, preferably 0.05 mm or more and 5 mm or less, and more preferably 0.1 mm or more and 1 mm or less, thereby making it easier to laminarize the flow of the liquid in the laminarization section 8A while preventing the pressure loss of the liquid L in the laminarization section 8A from becoming too large or too small.

[0076] Furthermore, in the resistivity adjustment device 1, the length of each of the multiple capillaries 8C is 1 mm or more and 1000 mm or less, preferably 5 mm or more and 500 mm or less, and more preferably 10 mm or more and 100 mm or less, thereby preventing the pressure loss of the liquid L in the laminarization section 8A from becoming excessively large or small.

[0077] Furthermore, in the resistivity adjusting device 1, the length of the laminarization section 8A is 1% or more, preferably 10% or more, and more preferably 50% or more of the length of the bypass pipe 8, which makes it easier to laminarize the flow of liquid in the bypass pipe 8.

[0078] Furthermore, in the resistivity adjusting device 1, by providing the branching module 11 and the junction module 12, it is possible to easily realize a branching structure from the liquid supply pipe 3 to the upstream module via pipe 71 and the bypass pipe 8, and a junction structure from the downstream module via pipe 72 and the bypass pipe 8 to the liquid discharge pipe 4. In particular, since the bypass pipe 8 has a laminarization section 8A composed of a plurality of thin tubes 8C, the bypass pipe 8 can be easily connected to the liquid supply pipe 3 and the liquid discharge pipe 4 via the branching module 11 and the junction module 12. Moreover, by extending the laminarization section 8A from the branching module 11 to the junction module 12, it is possible to easily form the laminarization section 8A and to easily laminarize the flow of the liquid L in the laminarization section 8A.

[0079] Furthermore, since the resistivity adjusting device 1 includes the gas supply pipe 5 and the gas exhaust pipe 6, the adjusting gas G can be easily supplied to and exhausted from the gas phase area GA of the hollow fiber membrane module 2.

[0080] Moreover, in the resistivity adjusting device 1, by providing the valve 9, it is possible to easily adjust the flow distribution ratio of the liquid L between the module via pipe 7 and the bypass pipe 8. Moreover, since the valve 9 is attached to the module via pipe 7, it is possible to suppress the valve 9 from hindering laminar flow in the bypass pipe 8.

[0081] In the resistivity adjusting method of the present embodiment, in the resistivity adjusting device 1, the liquid L is supplied to the liquid supply pipe 3, and an adjustment gas G is supplied to the gas phase side area GA of the hollow fiber membrane module 2, thereby adjusting the resistivity of the liquid L. This makes it possible to suppress, with a simple configuration, fluctuations in the resistivity of the resistivity adjusting liquid L2 even when the flow rate of the supplied liquid L fluctuates.

[0082] Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment.

[0083] For example, in the above embodiment, the resistivity adjusting device 1 has been described as including the gas supply pipe 5 and the gas exhaust pipe 6. However, as long as the adjusting gas G can be supplied to the gas phase side area GA of the hollow fiber membrane module 2, the resistivity adjusting device 1 may not include at least one of the gas supply pipe 5 and the gas exhaust pipe 6.

[0084] In the above embodiment, the resistivity adjusting device 1 has been described as including the valve 9. However, if the distribution ratio of the liquid L between the module via pipe 7 and the bypass pipe 8 can be adjusted by means other than the valve 9, the resistivity adjusting device 1 may not include the valve 9. Also, when the distribution ratio of the liquid L between the module via pipe 7 and the bypass pipe 8 is not adjusted, the resistivity adjusting device 1 may not include the valve 9.

[0085] In the above embodiment, the resistivity adjusting device 1 has been described as including the branching module 11 and the merging module 12. However, it is possible to distribute the liquid L supplied to the liquid supply pipe 3 to the upstream module via pipe 71 and the bypass pipe 8 by means other than the branching module 11 and the merging module 12, and to merge the adjusting gas-added liquid L1 supplied to the downstream module via pipe 72 and the liquid L supplied to the bypass pipe 8. If possible, the resistivity adjusting device 1 may not include at least one of the branching module 11 and the merging module 12. In this case, the liquid supply pipe 3 may be directly connected to the upstream module via pipe 71 and the bypass pipe 8, and the liquid discharge pipe 4 may be directly connected to the downstream module via pipe 72 and the bypass pipe 8. EXAMPLES

[0086] Next, examples of the present invention will be described, but the present invention is not limited to the following examples.

[0087] Example 1 A resistivity adjusting device of Example 1 was produced. The resistivity adjusting device of Example 1 was the same as the resistivity adjusting device 1 shown in Figures 1, 3 and 4, except for the following. In the resistivity adjusting device of Example 1, SEPAREL PF-001L-NA manufactured by DIC Corporation was used as a hollow fiber membrane module, and a laminar flow layer consisting of a plurality of capillaries was formed by bundling 9000 capillaries having an outer diameter of 0.225 mm, an inner diameter of 0.175 mm and a length of 110 mm. In the resistivity adjusting device of Example 1, the inner diameter (diameter) of the liquid supply pipe was 10 mm, the inner diameter (diameter) of the liquid discharge pipe was 10 mm, and the inner diameter (diameter) of the module via pipe (upstream module via pipe and downstream module via pipe) was 4 mm.

[0088] Comparative Example 1 A resistivity adjusting device of Comparative Example 1 was produced. The resistivity adjusting device of Comparative Example 1 was the same as that of Example 1, except that a single tube having an outer diameter of 8 mm, an inner diameter of 6 mm, and a length of 110 mm was used as the bypass pipe.

[0089] (evaluation) The resistivity adjusting device of Example 1 and the resistivity adjusting device of Comparative Example 1 were used to carry out the following measurements. In an environment of room temperature (25°C), a liquid at 25°C was supplied to the liquid supply pipe at a flow rate of 8 L, and an adjustment gas at 25°C and 0.1 MPa was supplied to the gas supply pipe. At this time, the distribution ratio of the liquid between the module via pipe and the bypass pipe was adjusted by adjusting the opening and closing of the valve so that the resistivity adjusting liquid had a predetermined resistivity value. Ultrapure water was used as the liquid. Carbon dioxide was used as the adjustment gas. Five conditions of 0.1 MΩ·cm, 0.4 MΩ·cm, 0.6 MΩ·cm, 0.8 MΩ·cm, and 1.0 MΩ·cm were set as the predetermined resistivity values. Then, in the valve state of each resistivity value, the flow rate of the liquid supplied to the liquid supply pipe was changed to 16 L / mm, 12 L / mm, 8 L / mm, 4 L / mm, and 1 L / mm in sequence every 5 minutes, and the resistivity value of the resistivity adjusting liquid was measured. Moreover, the pressure loss of the liquid in the bypass pipe was measured under the condition that the resistivity adjusting liquid was 1.0 MΩ·cm. The measurement results of Example 1 are shown in FIG.

[0090] As shown in Fig. 6, in the resistivity adjusting device of Comparative Example 1, under conditions where the resistivity of the resistivity adjusting liquid at a flow rate of 8 L was 0.1 MΩ·cm, the fluctuation in resistivity due to the fluctuation in the liquid flow rate was small. However, under other flow rate conditions, the fluctuation in resistivity due to the fluctuation in the liquid flow rate became large. In particular, the lower the flow rate of the liquid, the larger the fluctuation in resistivity.

[0091] In contrast, as shown in Figure 5, in the resistivity adjustment device of Example 1, the fluctuation in resistivity due to fluctuations in the liquid flow rate was small under any flow rate conditions, and even when the liquid flow rate was low, the fluctuation in resistivity did not become large.

[0092] The following measurements were performed using the resistivity adjustment device of Comparative Example 1. In an environment of room temperature (25°C), a liquid at 25°C was supplied to the liquid supply pipe at a flow rate of 16 L, and an adjustment gas at 25°C and 0.1 MPa was supplied to the gas supply pipe. At this time, the inner diameter and length of the bypass pipe were adjusted so that the pressure loss of the liquid in the bypass pipe was 0.09 Pa. In addition, in an environment of room temperature (25°C), a liquid at 25°C was supplied to the liquid supply pipe at a flow rate of 8 L, and an adjustment gas at 25°C and 0.1 MPa was supplied to the gas supply pipe. At this time, the distribution ratio of the liquid between the module via pipe and the bypass pipe was adjusted by adjusting the opening and closing of the valve so that the resistivity value of the resistivity adjustment liquid was 1.0 MΩ·cm. Ultrapure water was used as the liquid. Carbon dioxide was used as the adjustment gas. Then, the flow rate of the liquid supplied to the liquid supply pipe was changed from 16 L / mm to 0.7 L / mm, and the pressure loss of the liquid in the module via pipe and the bypass pipe was measured. The pressure loss of the liquid in the module via pipe and the bypass pipe was defined as the pressure loss of the liquid from the upstream module via pipe through the hollow fiber membrane module to the downstream module via pipe. The measurement results are shown in Figure 7. For reference, Figure 7 shows the pressure loss of the liquid in the bypass pipe when the liquid is in laminar flow in the bypass pipe.

[0093] As shown in Fig. 7, in the resistivity adjusting device of Comparative Example 1, the liquid is turbulent in the bypass pipe, so the pressure loss of the liquid in the bypass pipe has an exponential relationship with the flow rate of the liquid. On the other hand, the flow rate of the liquid supplied to the module via pipe is smaller than the flow rate of the liquid supplied to the bypass pipe. Therefore, compared with the pressure loss of the liquid in the bypass pipe, the pressure loss of the liquid in the module via pipe and the hollow fiber membrane module can be considered to be in a proportional relationship with the flow rate of the liquid, regardless of whether the liquid flowing through the module via pipe and the hollow fiber membrane module is turbulent or not. In other words, the tendency of pressure loss is significantly different between the liquid in the bypass pipe and the liquid in the module via pipe and the hollow fiber membrane module.

[0094] For example, when liquid is supplied to the bypass pipe at a flow rate of 16 L / min, the pressure loss of the liquid in the bypass pipe is about 0.09 Pa regardless of whether the flow of the liquid in the bypass pipe is turbulent or laminar. However, when liquid is supplied to the bypass pipe at a flow rate of 7 L / min, which is smaller than 16 L / min, the pressure loss of the liquid in the bypass pipe where the flow of the liquid is laminar is about 0.04 Pa, whereas the pressure loss of the liquid in the bypass pipe where the flow of the liquid is turbulent is about 0.015 Pa. In other words, the pressure loss of the liquid in the bypass pipe where the flow of the liquid is turbulent is smaller than that in the bypass pipe where the flow of the liquid is laminar. As a result, the distribution ratio of the liquid in the bypass pipe to the module via pipe becomes larger. Note that when liquid is supplied to the bypass pipe at a flow rate greater than 16 L / min, the opposite tendency occurs.

[0095] For this reason, in the resistivity adjusting device of Comparative Example 1, the distribution ratio of the liquid between the module via pipe and the bypass pipe fluctuates (disintegrates) with the fluctuation in the flow rate of the supplied liquid, and the resistivity of the resistivity adjusting liquid fluctuates, as shown in Fig. 6. In particular, when the flow rate of the liquid supplied to the resistivity adjusting device becomes small, the distribution ratio of the liquid in the bypass pipe to the module via pipe increases, and the resistivity of the resistivity adjusting liquid increases.

[0096] In contrast, in the resistivity adjusting device of Example 1, the flow of liquid in the bypass pipe is laminarized compared to the resistivity adjusting device of Comparative Example 1, and therefore the pressure loss of the liquid in the bypass pipe is proportional to the flow rate of the liquid. In other words, the tendency of the pressure loss of the liquid in the bypass pipe is close to the tendency of the pressure loss of the liquid in the module intermediate pipe and the hollow fiber membrane module.

[0097] Therefore, as shown in Fig. 5, in the resistivity adjusting device of Example 1, even if the flow rate of the supplied liquid fluctuates, the distribution ratio of the liquid between the module via pipe and the bypass pipe is suppressed from fluctuating, and it is considered that the fluctuation of the resistivity of the resistivity adjusting liquid is suppressed. In particular, even if the flow rate of the liquid supplied to the resistivity adjusting device becomes small, the increase in the distribution ratio of the liquid in the bypass pipe to the module via pipe is suppressed, and therefore it is considered that the increase in the resistivity of the resistivity adjusting liquid is suppressed. [Explanation of symbols]

[0098] 1...resistivity adjusting device, 2...hollow fiber membrane module, 3...liquid supply pipe, 3A...flow path, 4...liquid discharge pipe, 4A...flow path, 5...gas supply pipe, 6...gas discharge pipe, 6A...valve, 7...module via pipe, 8...bypass pipe, 8A...laminarization section, 8B...bypass housing, 8C...narrow tube, 8D...flow path, 8E...first sealing section, 8F...upstream end face, 8G...second sealing section, 8H...downstream end face, 9...valve, 11...branching module, 11A... Flow path, 12...junction module, 12A...flow path, 21...hollow fiber membrane, 22...housing, 22A...liquid supply port, 22B...liquid discharge port, 22C...gas supply port, 22D...gas discharge port, 71...upstream module via pipe, 71A...flow path, 72...downstream module via pipe, 72A...flow path, FD...flow direction, G...adjusting gas, GA...gas phase side region, L...liquid, L1...liquid with added adjusting gas, L2...liquid for adjusting resistivity, LA...liquid phase side region.

Claims

1. a hollow fiber membrane module divided by a hollow fiber membrane into a liquid phase side region to which a liquid to be adjusted in resistivity is supplied and a gas phase side region to which an adjustment gas for adjusting the resistivity of the liquid is supplied; A liquid supply pipe; A liquid discharge pipe; a module passing pipe that is in communication with the liquid phase side region of the hollow fiber membrane module, the liquid supply pipe, and the liquid discharge pipe and passes through the hollow fiber membrane module; a bypass pipe that is connected to the liquid supply pipe and the liquid discharge pipe and bypasses the hollow fiber membrane module, The bypass pipe has a laminar flow section formed of a plurality of capillaries thinner than the module via pipe. Resistivity adjustment device.

2. the laminarization unit is configured so that, when ultrapure water is supplied as the liquid to the bypass pipe at a specified flow rate, the liquid becomes a laminar flow in the laminarization unit. The resistivity adjusting device according to claim 1 .

3. the laminarization section is set so that the Reynolds number in the laminarization section is 2300 or less when ultrapure water is supplied as the liquid to the bypass pipe at a specified flow rate. The resistivity adjusting device according to claim 1 or 2.

4. The number of the plurality of capillaries is 5 or more. The resistivity adjusting device according to claim 1 or 2.

5. The inner diameter of each of the plurality of capillaries is 0.01 mm or more and 10 mm or less. The resistivity adjusting device according to claim 1 or 2.

6. The length of each of the plurality of capillaries is 1 mm or more and 1000 mm or less. The resistivity adjusting device according to claim 1 or 2.

7. The length of the laminarization portion is 1% or more of the length of the bypass pipe. The resistivity adjusting device according to claim 1 or 2.

8. a branching module connected to the liquid supply pipe, the module via pipe, and the bypass pipe to communicate the liquid supply pipe, the module via pipe, and the bypass pipe; a confluence module connected to the liquid discharge pipe, the module via pipe, and the bypass pipe to communicate the liquid discharge pipe, the module via pipe, and the bypass pipe; The laminarization section extends from the branching module to the joining module. The resistivity adjusting device according to claim 1 or 2.

9. a gas supply pipe connected to the gas phase region for supplying the adjusting gas to the gas phase region; A gas exhaust pipe connected to the gas phase side region for exhausting the adjustment gas from the gas phase side region, The resistivity adjusting device according to claim 1 or 2.

10. a valve attached to the module via pipe for adjusting a distribution ratio of the liquid between the module via pipe and the bypass pipe; The resistivity adjusting device according to claim 1 or 2.

11. In the resistivity adjusting device according to any one of claims 1 to 10, the resistivity of the liquid is adjusted by supplying the liquid to the liquid supply pipe and supplying the adjusting gas to the gas phase side region of the hollow fiber membrane module. Resistivity adjustment method.

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