Electrodialysis device and manufacturing method thereof

Abstract

An electrodialysis apparatus according to one embodiment of the present invention comprises an ion exchange membrane for exchanging ions; and a gasket in contact with the ion exchange membrane to seal the ion exchange membrane. The gasket comprises a first gasket located on one side of the ion exchange membrane and a second gasket located on the other side of the ion exchange membrane. The first gasket comprises a first main gasket and a first auxiliary gasket surrounding the first main gasket. The thermal expansion coefficient of the first main gasket is smaller than that of the first auxiliary gasket.

Description

[Technical Field]

[0001] The present invention relates to an electrodialysis device and a method for manufacturing the same, and more particularly to an electrodialysis device including an ion exchange membrane and a method for manufacturing the same. [Background technology]

[0002] An electrodialysis device is a device in which cation exchange membranes and anion exchange membranes are arranged alternately, and when a direct current voltage is applied across both ends of the membranes, cations and anions in the inflowing water (raw water) pass through the respective ion exchange membranes, and desalinated water and treated water containing a concentrate are alternately produced and discharged from the cells. Typically, such electrodialysis devices are used for desalination of seawater and wastewater treatment, etc.

[0003] The stacked ion exchange membranes of such an electrodialysis device are easy to join and are pressed with side rods to prevent the solution from leaking out, and gaskets are attached to both sides of the ion exchange membrane to seal the ion exchange membrane.

[0004] Generally, gaskets are made by adding small amounts of various additive elements to polypropylene (PP), such as FKM (Fluororubber), VMQ (Vynylmethyl silicon rubber), EPDM (ethylene propylene diene rubber), and NBR (Acrylonitrile butadiene rubber).

[0005] When an electrodialysis device is used for a long period of time, the gaskets will thermally expand at certain temperatures due to the influence of deposits, etc. When the gaskets expand, the ion exchange membranes that are crimped together also expand, resulting in a decrease in the ion exchange performance for electrodialysis. Summary of the Invention [Problem to be solved by the invention]

[0006] SUMMARY OF THE INVENTION An object of the present invention is to provide an electrodialysis device capable of minimizing thermal deformation and extending the life of an ion exchange membrane, and a method for manufacturing the same. [Means for solving the problem]

[0007] An electrodialysis apparatus according to one embodiment of the present invention includes an ion exchange membrane that exchanges ions; and a gasket that contacts the ion exchange membrane and seals the ion exchange membrane, the gasket including a first gasket located on one side of the ion exchange membrane and a second gasket located on the other side of the ion exchange membrane, the first gasket including a first main gasket and a first auxiliary gasket surrounding the first main gasket, and the thermal expansion coefficient of the first main gasket is smaller than that of the first auxiliary gasket.

[0008] The first auxiliary gasket may include a first upper auxiliary gasket located above the first main gasket and a first lower auxiliary gasket located below the first main gasket, and the first upper auxiliary gasket and the first lower auxiliary gasket may be made of the same material.

[0009] The first main gasket may include polyethylene terephthalate (PET), and the first auxiliary gasket may include polypropylene (PP).

[0010] The second gasket may include a second main gasket and a second auxiliary gasket surrounding the second main gasket, and the thermal expansion coefficient of the second main gasket may be smaller than that of the second auxiliary gasket.

[0011] The second auxiliary gasket may include a second upper auxiliary gasket located above the second main gasket and a second lower auxiliary gasket located below the second main gasket, and the second upper auxiliary gasket and the second lower auxiliary gasket may be made of the same material.

[0012] In addition, a method for manufacturing an electrodialysis device according to one embodiment of the present invention includes the steps of manufacturing a first gasket by a multiple injection method; manufacturing a second gasket by the multiple injection method; and sealing an ion exchange membrane with the first gasket and the second gasket, wherein the step of manufacturing the first gasket includes the steps of forming a first lower auxiliary gasket in an injection mold, forming a first main gasket on the first lower auxiliary gasket formed in the injection mold, and forming a first upper auxiliary gasket on the first main gasket formed in the injection mold, and the thermal expansion coefficient of the first main gasket is smaller than that of the first lower auxiliary gasket or the first upper auxiliary gasket.

[0013] The step of manufacturing the second gasket may include forming a second lower auxiliary gasket in the injection mold, forming a second main gasket on the second lower auxiliary gasket formed in the injection mold, and forming a second upper auxiliary gasket on the second main gasket formed in the injection mold, and the thermal expansion coefficient of the second main gasket may be smaller than the thermal expansion coefficient of the second lower auxiliary gasket or the second upper auxiliary gasket.

[0014] In addition, a manufacturing method of an electrodialysis apparatus according to another embodiment of the present invention includes the steps of manufacturing a first gasket by a multiple extrusion method; manufacturing a second gasket by a multiple extrusion method; and sealing an ion exchange membrane with the first gasket and the second gasket, wherein the manufacturing step of the first gasket includes the steps of manufacturing a first main gasket disc and a first auxiliary gasket disc having a higher thermal expansion coefficient than the first main gasket disc; feeding the first main gasket disc and the first auxiliary gasket disc to extrusion rollers to heat them; and feeding the first main gasket disc and the first auxiliary gasket disc that have passed through the extrusion rollers to bonding rollers to attach them.

[0015] The step of manufacturing the second gasket may include the steps of manufacturing a second main gasket disc and a second auxiliary gasket disc having a higher thermal expansion coefficient than the second main gasket disc, feeding the second main gasket disc and the second auxiliary gasket disc to the extrusion rollers to heat them, and feeding the second main gasket disc and the first auxiliary gasket disc that have passed through the extrusion rollers to the bonding rollers to attach them.

[0016] The extrusion rollers may include a first extrusion roller that extrudes the first main gasket disc and a second extrusion roller that extrudes the first auxiliary gasket disc, wherein the first extrusion roller is a heating roller that heats the first main gasket disc, and the second extrusion roller is a mixing roller that heats and cools the first auxiliary gasket disc.

[0017] The second extrusion roller may include a sub-cooling roller that cools the outer surface of the first auxiliary gasket disc, and a sub-heating roller that heats the inner surface of the first auxiliary gasket disc.

[0018] The bonding roller may be a cooling roller that cools the first main gasket disc and the first auxiliary gasket disc. [Effects of the Invention]

[0019] The electrodialysis device according to one embodiment of the present invention minimizes thermal deformation and is advantageous in sealing to prevent leakage. Therefore, thermal deformation of the ion exchange membrane can be suppressed, and the life of the ion exchange membrane can be improved. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a schematic perspective view of an electrodialysis device according to one embodiment of the present invention; [Figure 2]FIG. 2 is a cross-sectional view of FIG. 1. [Figure 3] 1 is a flowchart showing a method for manufacturing an electrodialysis device according to an embodiment of the present invention. [Figure 4] 4 is a diagram illustrating a part of the manufacturing method of FIG. 3. [Figure 5] 10 is a flowchart sequentially illustrating a method for manufacturing an electrodialysis device according to another embodiment of the present invention. [Figure 6] 6 is a diagram illustrating a part of the manufacturing method of FIG. 5. DETAILED DESCRIPTION OF THE INVENTION

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily carry out the present invention. As the present invention may be embodied in various different forms, it is not limited to the embodiments set forth herein.

[0022] FIG. 1 is a schematic perspective view of an electrodialysis device according to one embodiment of the present invention, and FIG. 2 is a cross-sectional view of FIG.

[0023] As shown in FIGS. 1 and 2, an electrodialysis device according to one embodiment of the present invention includes an ion exchange membrane 100 and a gasket 200 that contacts the ion exchange membrane 100 and seals the ion exchange membrane 100 .

[0024] The ion exchange membrane 100 may have a structure in which cation exchange membranes and anion exchange membranes are alternately stacked. Such an ion exchange membrane 100 may include an active region (not shown) located in the center and an inactive region (not shown) surrounding the active region (not shown). The active region (not shown) is a region that exhibits ion exchange performance and may occupy 70 to 80% of the area of ​​the ion exchange membrane 100. Such an ion exchange membrane 100 may contain approximately 40% water.

[0025] The gasket 200 may include a first gasket 210 located on one side of the ion exchange membrane 100 and a second gasket 220 located on the other side of the ion exchange membrane 100 .

[0026] In this embodiment, for the sake of convenience, only the first gasket 210 and the second gasket 220 located on the top and bottom of the ion exchange membrane 100, respectively, are shown, but the ion exchange membrane 100 and the gasket 200 can be installed by stacking them alternately.

[0027] The lower surface of the first gasket 210 contacts the ion exchange membrane 100, and the upper surface of the second gasket 220 contacts the ion exchange membrane 100, thereby preventing the solution inside the ion exchange membrane 100 from leaking out.

[0028] The first gasket 210 may include a first main gasket 211 and a first secondary gasket 212 that surrounds the first main gasket 211 .

[0029] In this case, the thermal expansion coefficient of the first main gasket 211 can be smaller than that of the first auxiliary gasket 212. Therefore, it is possible to minimize thermal deformation while ensuring the physical properties of the first gasket 210 that are advantageous for sealing. That is, the first main gasket 211 can withstand pressure by using a material that can withstand pressure and has a small thermal expansion coefficient, thereby minimizing thermal deformation. In addition, the first auxiliary gasket 212, which surrounds the first main gasket 211 and is exposed to the outside, is made of a material with a large thermal expansion coefficient, which softens its surface and enables close contact, thereby being advantageous for sealing.

[0030] The first main gasket 211 may include polyethylene terephthalate (PET), and the first auxiliary gasket 212 may include polypropylene (PP), but is not limited thereto and various materials may be used.

[0031] The first auxiliary gasket 212 may include a first upper auxiliary gasket 212u located above the first main gasket 211 and a first lower auxiliary gasket 212d located below the first main gasket 211. In this case, the first upper auxiliary gasket 212u and the first lower auxiliary gasket 212d may include the same material. For example, the first upper auxiliary gasket 212u and the first lower auxiliary gasket 212d may include polypropylene (PP).

[0032] The second gasket 220 may include a second main gasket 221 and a second auxiliary gasket 222 surrounding the second main gasket 221 .

[0033] In this case, the thermal expansion coefficient of the second main gasket 221 can be smaller than that of the second auxiliary gasket 222. Therefore, it is possible to minimize thermal deformation while ensuring the physical properties of the second gasket 220 that are advantageous for sealing. That is, the second main gasket 221 can withstand pressure by using a material that can withstand pressure and has a small thermal expansion coefficient, thereby minimizing thermal deformation. In addition, the second auxiliary gasket 222, which surrounds the second main gasket 221 and is exposed to the outside, can have a soft surface by using a material that has a large thermal expansion coefficient.

[0034] The second main gasket 221 may include polyethylene terephthalate (PET), and the second auxiliary gasket 222 may include polypropylene (PP), but is not limited thereto and various materials may be used.

[0035] The coefficient of thermal expansion is calculated as length x coefficient of thermal expansion x temperature change. The coefficient of thermal expansion of polyethylene terephthalate (PET) is 250 um / (m·°C), and the coefficient of thermal expansion of polypropylene (PP) may be 413 um / (m·°C).

[0036] The second auxiliary gasket 222 may include a second upper auxiliary gasket 222u located above the second main gasket 221 and a second lower auxiliary gasket 222d located below the second main gasket 221. In this case, the second upper auxiliary gasket 222u and the second lower auxiliary gasket 222d may include the same material. For example, the second upper auxiliary gasket 222u and the second lower auxiliary gasket 222d may include polypropylene (PP).

[0037] As described above, the gasket 200 of the electrodialysis apparatus according to one embodiment of the present invention includes a first gasket 210 and a second gasket 220. The first gasket 210 includes a first main gasket 211 and a first auxiliary gasket 212 having a thermal expansion coefficient greater than that of the first main gasket 211. The second gasket 220 includes a second main gasket 221 and a second auxiliary gasket 222 having a thermal expansion coefficient greater than that of the second main gasket 221. This minimizes thermal deformation and prevents leakage, providing favorable sealing. Therefore, the thermal deformation of the ion exchange membrane 100 can be suppressed, thereby extending the life of the ion exchange membrane 100.

[0038] Meanwhile, a method for manufacturing the electrodialysis device according to the embodiment will be described in detail below with reference to the drawings.

[0039] FIG. 3 is a flow chart sequentially illustrating a method for manufacturing an electrodialysis device according to an embodiment of the present invention, and FIG. 4 is a diagram illustrating a part of the manufacturing method shown in FIG.

[0040] As shown in FIG. 3, in the method for manufacturing an electrodialysis device according to an embodiment of the present invention, first, a first gasket 210 is manufactured by a multiple injection method (S10).

[0041] The method for manufacturing the first gasket by the multiple injection method will be described in detail below.

[0042] 4, a first lower auxiliary gasket material 2d is injected into the injection mold 10 to form a first lower auxiliary gasket 212d in the injection frame 11. Then, a first main gasket material 1 is injected onto the first lower auxiliary gasket 212d formed in the injection mold 10 to form a first main gasket 211. Then, a first upper auxiliary gasket material 2u is injected onto the first main gasket 211 formed in the injection mold 10 to form a first upper auxiliary gasket 212u.

[0043] In this case, the thermal expansion coefficient of the first main gasket 211 may be smaller than that of the first lower auxiliary gasket 212d or the first upper auxiliary gasket 212u, thereby minimizing thermal deformation and leakage in the first gasket 210.

[0044] Next, the second gasket 220 is manufactured using the same multiple injection method as the manufacturing method for the first gasket 210 (S20). That is, a second lower auxiliary gasket material is injected into the injection mold 10 to form a second lower auxiliary gasket 222d in the injection frame 11. Then, a second main gasket material is injected onto the second lower auxiliary gasket 222d formed in the injection mold 10 to form a second main gasket 221. Then, a second upper auxiliary gasket material is injected onto the second main gasket 221 formed in the injection mold 10 to form a second upper auxiliary gasket 222u.

[0045] In this case, the thermal expansion coefficient of the second main gasket 221 may be smaller than that of the second lower auxiliary gasket 222d or the second upper auxiliary gasket 222u, thereby minimizing thermal deformation and leakage in the second gasket 220.

[0046] Next, the ion exchange membrane 100 is sealed with the first gasket 210 and the second gasket 220 to manufacture the electrodialysis device (S30).

[0047] In this way, the first lower auxiliary gasket 212d or the first upper auxiliary gasket 212u can be attached to the first main gasket 211 using the multiple injection method without using a separate adhesive, which simplifies the manufacturing process and improves the adhesive strength between them.

[0048] In addition, the multiple injection molding method can be used to manufacture a gasket that minimizes thermal deformation and prevents leakage, thereby suppressing thermal deformation of the ion exchange membrane 100 and thereby improving the lifespan of the ion exchange membrane 100.

[0049] Meanwhile, in the above embodiment, the first gasket or the second gasket is manufactured by a multiple injection method, but other embodiments are possible in which the first gasket or the second gasket is manufactured by a multiple extrusion method.

[0050] Hereinafter, a method for manufacturing an electrodialysis device according to another embodiment of the present invention will be described in detail with reference to FIGS.

[0051] FIG. 5 is a flow chart sequentially illustrating a method for manufacturing an electrodialysis device according to another embodiment of the present invention, and FIG. 6 is a diagram illustrating a part of the manufacturing method of FIG.

[0052] As shown in FIG. 5, in the method for manufacturing an electrodialysis device according to another embodiment of the present invention, first, a first gasket 210 is manufactured by a multiple extrusion method (S100).

[0053] The method for manufacturing the first gasket by the multiple extrusion method will be described in detail below. As shown in Fig. 6, a first main gasket disk 3 and a first auxiliary gasket disk 4 having a higher thermal expansion coefficient than the first main gasket disk 3 are manufactured. The first main gasket disk 3 may include polyethylene terephthalate (PET), and the first auxiliary gasket disk 4 may include polypropylene (PP). The first auxiliary gasket disks 4 may include a first upper auxiliary gasket disk 4u and a first lower auxiliary gasket disk 4d.

[0054] Then, the first main gasket disc 3 and the first auxiliary gasket disc 4 are fed to the extrusion rollers 20 and heated.

[0055] Here, the extrusion rollers 20 may include a first extrusion roller 21 for extruding the first main gasket disc 3 and a second extrusion roller 22 for extruding the first auxiliary gasket disc 4 .

[0056] The first extrusion roller 21 may be a heating roller that heats the first main gasket disc 3. Therefore, the surface of the first main gasket disc 3 is heated to a temperature of 100 to 160 degrees Celsius using the first extrusion roller 21, thereby making it adhesive. Such a first extrusion roller 21 may heat the first main gasket disc 3 by induction heating using a heating coil disposed on the side, or may heat the first main gasket disc 3 by disposing a heating element inside the first extrusion roller 21. However, the heating method of the first extrusion roller 21 is not necessarily limited to this, and various structures are possible. The second extrusion roller 22 may be a mixing roller that heats and cools the first auxiliary gasket disc 4. The second extrusion roller 22 may include a sub-cooling roller 22C that cools the outer surface of the first auxiliary gasket disc 4 and a sub-heating roller 22H that heats the inner surface of the first auxiliary gasket disc 4.

[0057] The sub-heating roller 22H is used to heat the inner surface of the first auxiliary gasket disc 4 so that it can be attached, and the sub-cooling roller 22C is used to cool the outer surface of the first auxiliary gasket disc 4 so that it can be pressed.

[0058] The first main gasket disc 3 and the first auxiliary gasket disc 4 that have passed through the extrusion roller 20 are then supplied to and adhered to the bonding roller 30. The bonding roller 30 may be a cooling roller that cools the first main gasket disc 3 and the first auxiliary gasket disc 4. In this way, by using the bonding roller 30 to press the first main gasket disc 3 and the first auxiliary gasket disc 4 together while cooling them, the first main gasket disc 3 and the first auxiliary gasket disc 4 are adhered to each other, thereby producing the first gasket 210 including the first main gasket 211 and the first auxiliary gasket 212.

[0059] Next, the second gasket 220 is manufactured by the same multi-extrusion method as the first gasket 210 (S200). A second main gasket disc and a second auxiliary gasket disc having a higher thermal expansion coefficient than the second main gasket disc are manufactured. The second auxiliary gasket discs may include a second upper auxiliary gasket disc and a second lower auxiliary gasket disc. The second main gasket disc and the second auxiliary gasket disc are then fed to the extrusion rollers 20 and heated. After passing through the extrusion rollers 20, the second main gasket disc and the second auxiliary gasket disc are then fed to the bonding rollers 30 and attached.

[0060] Next, the ion exchange membrane 100 is sealed with the first gasket 210 and the second gasket 220 to manufacture the electrodialysis device (S300).

[0061] In this way, the first lower auxiliary gasket 212d or the first upper auxiliary gasket 212u can be attached to the first main gasket 211 using a multiple extrusion method without using a separate adhesive, which simplifies the manufacturing process and improves the adhesive strength between them.

[0062] In addition, the multi-extrusion method can be used to minimize thermal deformation and simultaneously manufacture a gasket that prevents leakage, thereby suppressing thermal deformation of the ion exchange membrane 100 and thereby improving the lifespan of the ion exchange membrane 100.

[0063] Although the present disclosure has been described through the preferred embodiments as described above, the present invention is not limited thereto, and it will be easily understood by those skilled in the art to which the present invention pertains that various modifications and variations can be made without departing from the scope of the following claims. [Explanation of symbols]

[0064] 100 Ion exchange membrane 200 gaskets 210 First Gasket 211 No. 1 main gasket 212 Second auxiliary gasket 220 Second gasket 221 No. 2 main gasket 222 Second auxiliary gasket

Claims

1. an ion exchange membrane that exchanges ions; and A gasket that contacts the ion exchange membrane and seals the ion exchange membrane. Including, The gasket a first gasket positioned on one side of the ion exchange membrane; and a second gasket located on the other side of the ion exchange membrane; Including, The first gasket First main gasket, and a first auxiliary gasket surrounding the first main gasket; Including, An electrodialysis apparatus wherein the first main gasket has a thermal expansion coefficient smaller than that of the first auxiliary gasket.

2. The first auxiliary gasket is a first upper auxiliary gasket located above the first main gasket; and a first lower auxiliary gasket located below the first main gasket; Including, 2. The electrodialysis apparatus according to claim 1, wherein the first upper auxiliary gasket and the first lower auxiliary gasket comprise the same material.

3. 2. The electrodialysis apparatus of claim 1, wherein the first main gasket comprises polyethylene terephthalate (PET) and the first auxiliary gasket comprises polypropylene (PP).

4. The second gasket is Second main gasket, and a second auxiliary gasket surrounding the second main gasket; Including, 2. The electrodialysis apparatus according to claim 1, wherein the second main gasket has a thermal expansion coefficient smaller than that of the second auxiliary gasket.

5. The second auxiliary gasket is a second upper auxiliary gasket located above the second main gasket; and a second lower auxiliary gasket located below the second main gasket; Including, The electrodialysis apparatus according to claim 4 , wherein the second upper auxiliary gasket and the second lower auxiliary gasket are made of the same material.

6. manufacturing a first gasket by a multiple injection method; manufacturing a second gasket by a multiple injection method; and sealing the ion exchange membrane with the first gasket and the second gasket Including, The step of manufacturing the first gasket includes: forming a first lower auxiliary gasket in an injection mold; forming a first main gasket on the first lower auxiliary gasket formed in the injection mold; and forming a first upper auxiliary gasket on the first main gasket formed in the injection mold; Including, A method for manufacturing an electrodialysis device, wherein the first main gasket has a smaller thermal expansion coefficient than the first lower auxiliary gasket or the first upper auxiliary gasket.

7. The step of manufacturing the second gasket includes: forming a second lower auxiliary gasket in the injection mold; forming a second main gasket on the second lower auxiliary gasket formed in the injection mold; and forming a second upper auxiliary gasket on the second main gasket formed in the injection mold; Including, 7. The method for manufacturing an electrodialysis device according to claim 6, wherein the second main gasket has a thermal expansion coefficient smaller than that of the second lower auxiliary gasket or the second upper auxiliary gasket.

8. manufacturing a first gasket by a multiple extrusion method; producing a second gasket by a multiple extrusion process; and sealing the ion exchange membrane with the first gasket and the second gasket Including, The step of manufacturing the first gasket includes: manufacturing a first main gasket disc and a first auxiliary gasket disc having a higher thermal expansion coefficient than the first main gasket disc; feeding the first main gasket disc and the first auxiliary gasket disc to an extrusion roller for heating; and feeding the first main gasket disc and the first auxiliary gasket disc that have passed through the extrusion rollers to a bonding roller for attachment; A method for manufacturing an electrodialysis device, comprising:

9. The step of manufacturing the second gasket includes: manufacturing a second main gasket disc and a second auxiliary gasket disc having a higher thermal expansion coefficient than the second main gasket disc; feeding the second main gasket disc and the second auxiliary gasket disc into the extrusion roller and heating them; and feeding the second main gasket disc and the first auxiliary gasket disc, which have passed through the extrusion roller, to the bonding roller for attachment; 9. The method for manufacturing an electrodialysis device according to claim 8, comprising:

10. The extrusion roller a first extrusion roller for extruding the first main gasket disc; and a second extrusion roller for extruding the first auxiliary gasket disc; Including, the first extrusion roller is a heating roller that heats the first main gasket disk, 10. The method for manufacturing an electrodialysis device according to claim 9, wherein the second extrusion roller is a mixing roller for heating and cooling the first auxiliary gasket disc.

11. The second extrusion roller is a sub-cooling roller for cooling the outer surface of the first auxiliary gasket disc; and a sub-heating roller for heating the inner surface of the first auxiliary gasket disc; The method for manufacturing an electrodialysis device according to claim 10, comprising:

12. 11. The method for manufacturing an electrodialysis apparatus according to claim 10, wherein the bonding roller is a cooling roller for cooling the first main gasket disc and the first auxiliary gasket disc.

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