JPH0143564B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing a gasket for an electrodialysis tank suitable for use in clamping type electrodialysis. In particular, the present invention relates to a method of manufacturing a gasket for an electrodialysis tank that integrates a current-carrying part or a spacer for a current-carrying part and a waterway part. Conventional clamp-type electrodialysis cells, in which a large number of cation-exchange membranes and anion-exchange membranes are alternately arranged between electrodes via gaskets and spacers, are generally used for electrolyte concentration, desalination, etc. It is being When performing electrodialysis using this electrodialysis tank, the most difficult point is to obtain uniform distribution of the fluid to the dialysis chambers formed within the dialysis tank, and to distribute the fluid to each dialysis chamber within the dialysis tank and to the outside. This is to prevent leakage. The critical current density and scale deposition in the dialysis tank are regulated by the worst room in the dialysis chamber, so uniform distribution of the liquid in the dialysis chamber is extremely important for efficient operation. Furthermore, leakage of fluid between the dialysis rooms and outside the room causes mixing and loss of dialysed fluid, rendering the dialysis process itself meaningless, and is also a very serious problem for dialysis tanks. In particular, the spacer of the electrodialysis tank gets clogged with dirt from the electrolyte solution supplied to the electrodialysis tank, so it usually requires disassembly and cleaning several times a year, but the accuracy of this operation is critical to the stable operation of the device. Also, if the assembly time can be reduced, it will greatly contribute to improving the efficiency of operation. For this reason, various proposals have been made to integrate gaskets and spacers, but none of them have fully achieved the above objectives or lacked the long-term durability that is essential for industrial equipment. There was a shortage, and all of them were inadequate. For example, a device proposed in Japanese Utility Model Publication No. 54-16914 has been proposed, but this is the same as the pressure molding method using a mold, which will be described later, and the mold itself or the habits of the press are exposed as they are in the molded gasket. Therefore, when a large number of gaskets and ion exchange membranes are stacked and used as in the field, the difference in thickness of each membrane is added up as is, and liquid leaks from localized thin parts, which is undesirable. This becomes more noticeable as the shape becomes larger. The present invention provides a gasket frame member made of a vulcanized rubber sheet,
A current-carrying part notch is provided, and adhesive is applied to at least a part of the cross section of each of at least two opposing sides of the notch, and a current-carrying part spacer having a width narrower than the notch is prevented from coming into contact with the adhesive. And 0.5mm~ from the notch cross section
It is placed in the notch with a gap of 20 mm.
Unvulcanized rubber is placed in a part including the gap between the adhesive and the current-carrying part spacer and the peripheral part of the current-carrying part spacer, and then vulcanized rubber for adhesion is placed by vulcanizing this. At least a part of each of at least two opposing sides of the current-carrying part notch and at least a part of the current-carrying part spacer are fixed and integrated using adhesive and vulcanized rubber for fixing. Provided is a method for manufacturing a gasket for an electrodialysis tank. The present invention not only fixes the current-carrying part notch and the current-carrying part spacer as described above, but also provides a method for manufacturing an electrodialysis gasket in which the notch of the current-carrying part and the spacer of the current-carrying part are fixed by the same method. Also provided. The present invention is disclosed in Japanese Patent Application No. 1983-57120 (name of invention:
It is preferable that the present invention be put to practical use in conjunction with the invention described in the specification of ``New Gasket for Electrodialyzer and Method for Producing the Same''. The invention described in the specification of the earlier application is an electrodialysis cell in which a gasket and a Shiodo spacer are fixed and integrated using glue and vulcanized rubber for fixation in the same manner as the present invention. The present invention relates to a gasket for use in gaskets and a method for manufacturing the same. The gasket frame member in the present invention is made of natural rubber, synthetic rubber such as chloroprene rubber, and a vulcanized rubber sheet made by adding these to each other or by adding other substances to them. is 0.2~2mm and JIS HS is 30°~
A hardness of 95° is preferred. The molding method is to first mold a sheet of vulcanized rubber using a calendar roll, etc., and then punch it out to make a gasket frame, or to make a band from the sheet of vulcanized rubber, butt the end faces of this, and then form this part. It is preferable that the gasket frame is formed by joining the gaskets by adhesive or other means. In other words, if the gasket frame is manufactured by pressure molding or injection molding using a mold, which has been widely used in the past, when a large number of gaskets are stacked together with an ion exchange membrane in a dialysis tank as a gasket, the mold itself will be damaged and the press Due to their tendency, the difference in thickness between each sheet adds up, causing liquid to leak from localized thin areas, which is undesirable. In the present invention, the spacer that is inserted into the current-carrying part or the current-carrying part and the channel part and integrated by vulcanizing unvulcanized rubber is preferably a mesh spacer that is conventionally generally used in dialysis chambers. For example, a lattice shape, a honeycomb shape, a mikoshiro shape, etc. are preferred, and a diagonal mesh shape is particularly preferred. Furthermore, the material is synthetic resin such as polyvinyl chloride, saran, polyethylene, polypropylene, etc.
ASTM Shore D hardness of 50° to 110° is preferred. As for the shore path section, any conventionally known shape may be used. However, from the viewpoint of ease of manufacture and handling, it is preferable that the spacer be connected to the current-carrying part and the tideway part. Furthermore, it is more preferable to insert the same spacer across the current-carrying part and the passageway part. In this case, the shape of the channel is preferably a shape that includes a communication hole notch in the shape of the spacer. By creating a shape like this,
The integrated cross section with the gasket frame is increased, durability is increased, and the effect of preventing liquid leakage is also enhanced. When fixing the spacer to the gasket frame member,
Preferably, the distance between the gasket frame fixed section and the spacer is 0.5 to 20 mm, more preferably 1 to 20 mm, so that the spacer does not touch the fixed section of the gasket.
It is desirable to insert spacers into the gasket frame member notches with a gap of 10 mm. In other words, if unvulcanized rubber is filled and vulcanized and fixed while the spacer is in contact with the fixed cross section of the gasket frame, the thickness of the vulcanized rubber will be poor, the spacer will be deformed during vulcanization, and the fixing force will be weak. Therefore, when a dialysis tank is assembled using such a gasket, liquid leakage and uneven distribution of the liquid occur, and deformation such as spacer dislocation is likely to occur due to several disassembly and reassembly, making it impractical. Also, if you create a gasket by leaving a gap of 20 mm or more between the fixed cross section of the gasket frame and the spacer, filling it with unvulcanized rubber and vulcanizing it to make it stick, the unvulcanized rubber will move in the lateral direction during vulcanization. The movement increases and spacer deformation occurs. Furthermore, since the thickness accuracy of the vulcanized rubber used for fixing is not very high, when a large number of vulcanized rubbers are stacked in a dialysis tank, this may cause liquid leakage, which is not preferable. The fixed portion is at least a portion of each of at least two opposing sides of the portion corresponding to the current-carrying portion of the spacer. In this case, durability is determined by adhesion on at least 50% of each corresponding side.
Preferable in terms of ease of handling. Furthermore, when inserting the spacer up to the shore path, it is preferable that the spacer is also fixed to the shore path. The spacer may be inserted into the notch of the gasket frame member and fixed after the vulcanized rubber sheet is molded into the gasket frame shape.For gasket frames formed by joining the ends of vulcanized rubber strips, After fixing spacers to each of the strips,
Other strips may be joined to form the gasket. The unvulcanized rubber used in the present invention includes natural rubber,
Synthetic rubber such as chloroprene, sealant such as thiocol, a mixture of these, or an unvulcanized rubber obtained by adding another substance to these is used. In this case, it is preferable to contain a rubber component contained in a vulcanized rubber sheet used as a gasket member. After adding an appropriate commonly used vulcanizing agent to this rubber, a cross section of the gasket member to which this rubber is bonded (glue is applied to the cross section)
The corresponding gap between the rubber and the spacer and a portion including the periphery of the spacer are filled with the unvulcanized rubber, and the unvulcanized rubber and the gasket frame member are roughly bonded using the adhesive, and then vulcanized. The spacer is integrated with the gasket frame member, thus producing a gasket. The form of unvulcanized rubber is either liquid or solid, and either can be used.However, after adding a vulcanizing agent and, if necessary, a vulcanization aid to solid unvulcanized rubber, a sheet is prepared. It is preferable to mold the material into a shape and then cut it into a corresponding shape before use. When fixing a vulcanized rubber sheet to a gasket frame, apply a rubber adhesive, preferably of the same composition as the unvulcanized rubber, to the cross section of the part of the frame to be fixed, and then apply the so-called co-glue to the unvulcanized rubber sheet. Become one with. When filling the mesh spacer and vulcanizing it, it is preferable to heat it if necessary, and it is also preferable to press it from above and below in a sandwich-like manner since this can make the thickness of the rubber being vulcanized uniform. The average thickness of the spacer to be inserted is - compared to the average thickness of the vulcanized rubber sheet used as a gasket member.
8% to +15%, preferably -5 to +10%, more preferably 0 to +10%, more preferably 0 to +20%
It is best to keep it within the range. Also, after vulcanization molding of unvulcanized rubber, the average thickness of this part is -8 to +15 compared to the average thickness of the vulcanized rubber sheet used as a gasket member.
%, preferably -5 to +10%, more preferably 0
The thickness should be ~+10%. In other words, if the vulcanization molding part and the spacer are thicker or thinner than the gasket member, fluid leakage is likely to increase when an electrodialysis cell is constructed, and a large amount of tightening force is required to prevent fluid leakage, and the frame etc. This increases the fatigue of the patient, causes distortion in the dialysis chamber, and tends to cause uneven distribution of the fluid. EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples in any way. Example 1 A vulcanized natural rubber sheet with a JIS HS hardness of 75° and a thickness of 0.5 m/m was formed into strips of width 30 m/m x length 693 m/m and width 72 m/m x length 356 m/m at a ratio of 1:1. It was cut according to the number of sheets. Next, a frame-shaped gasket frame with an area of 20.2 dm <sup>2</sup> was created by joining them together with rubber adhesive at the positions indicated by the broken lines in Figure 1. Next, 7 round holes with a diameter of 22 m/m and 7 square holes with a side of 26 m/m were drilled alternately in the wide strips above and below, so that the center spacing between the holes was even. Furthermore, in the area where the 26 m/m square hole was drilled, a notch was made 26 m/m wide toward the inside of the gasket frame, creating a gasket frame with a notch as shown in Figure 2. Next, the thickness is 0.52m/m, and the mesh pitch is 5m/m vertically.
A diagonal mesh spacer made of polypropylene with a width of 3 m/m and a shore hardness of 100 degrees was cut and inserted so as to have a gap of 1 m/m all around the inner circumference of this notched gasket frame. The cut spacer has a shape as shown in Figure 3, but when the spacer is inserted into the gasket frame, there is a position at the center of the width of the seven protrusions that will become the channels when forming the gasket, as indicated by 4 in Figure 3. The diameter of the hole is 22m/m, with the center of the hole being in line with the center of the 3 or 4 22m/m holes drilled in the wide band at the top and bottom of the gasket frame.
A total of 7 holes were drilled on the top and bottom (Figure 3-5). Next, add 1% vulcanizing agent to unvulcanized natural rubber and
A sheet with a thickness of 0.5 m/m and a width of 500 m/m was molded at ℃, and then cut into a width of 5 m/m and a length of 621 m/m. Next, glue made of the same composition as unvulcanized natural rubber was applied to the inner cross section of the two narrow (vertical) bands of the gasket frame.
After applying a so-called co-glue, this part and the cross section of the previously cut unvulcanized rubber piece were adhered by lightly butting them together by hand. Furthermore, this part was heated to 150℃ for 5 minutes.
Heat pressing is performed at a surface pressure of 5 kg/cm <sup>2</sup> to embed the spacer in unvulcanized natural rubber, and the two sides of the gasket frame and spacer are fixed by molding and vulcanization, making the gasket frame and spacer integral. By this, we created 300 gaskets for electrodialysis tanks, each having 7 channels with a liquid passage width of 26 m/m, a thickness of 0.5 m/m, and an effective current-carrying area of 19.6 <sup>dm2</sup> . The average thickness of the vulcanized portion of the unvulcanized natural rubber in the finished gasket was 0.52 m/m. The completed gasket is shown in Figure 4. In Fig. 4, 6 is the gasket body, 7 is a spacer whose two opposing sides are integrated with the gasket,
Reference numeral 8 indicates a vulcanized portion of the unvulcanized natural rubber, and reference numeral 9 indicates a communication hole for a diluted liquid flow and a concentrated liquid flow. 150 gaskets made using the above method were
It has a hole inlet and 4 hole outlets for the dilution chamber, and is also 150 mm.
The sheet has a 4-hole inlet and 3-hole outlet for the concentration chamber, and is made of Asahi Kasei Aciplex K-101 (cation exchange membrane).
150 sheets and 150 sheets of A-101 (anion exchange membrane) were assembled in the order to form an electrodialysis tank, and temporarily tightened with a fastening frame. The time required for this assembly was 2 people.
It was hot for 10 hours. Next, the assembled product was installed in a filter press type electrodialysis tank, and after tightening with a hydraulic press,
Diluted seawater of 1200 ppm was flowed into the concentration chamber and dilution chamber at a linear velocity of 8 cm/sec, but liquid leaked from the dialysis tank to the outside (hereinafter referred to as leak outside the tank), so it was tightened using a hydraulic press. The leakage outside the tank was set as "0". The pressure at this time is 2.2Kg/per effective current carrying area.
It was cm <sup>2</sup> G. Next, after stopping the supply of diluted seawater to the concentration chamber and sufficiently draining the concentration chamber liquid, we measured the leakage of diluted seawater into the concentration chamber (hereinafter referred to as tank leakage), which was 8c.c per minute per chamber. .It was hot. Furthermore, after flowing 1200 ppm diluted seawater into the concentration chamber again, desalination was performed using a partial circulation method at a temperature of 20 to 25°C, and the diluted solution outlet concentration was adjusted to 500 ppm. The limiting current density at this time was 0.51 A/dm <sup>2</sup> . Further, set the current density to 80% of this critical current density.
The operation was carried out for 10 days, and the average desalination capacity at this time was 3.0 m <sup>3</sup> /Hr. After this, I tried disassembling it, but there was no deformation of the gasket. After reassembling and measuring the time required for reassembly, the fastening pressure at which leakage outside the tank was ``0'', and the leakage inside the tank, the operation method was repeated three times: operating for 10 days and then disassembling. The results for each 10-day period were as follows.

[Table] After 30 days of operation, the critical current density was measured, and it was 0.51 A/dm ² , which was the same as the initial density. Example 2 A 0.5 m/m thick rubber sheet with the same specifications as used in Example 1 was made into a sheet with a width of 30 m/m x length of 698 m/m and a width of 30 m/m and a width of 698 m/m.
It was cut into strips measuring 67 m/m x 356 m/m in length at a ratio of 1:1, and a frame-shaped gasket frame with an area of 20.6 dm ² was made in the same manner as in Example 1. Next, seven round holes with a diameter of 22 m/m and square holes with a side of 39 m/m were alternately drilled in the wide strips above and below, so that the center spacing between the holes was even. Furthermore, for the part where the 39 m/m square hole was drilled, a gasket frame with a notch similar to that shown in Fig. 2 was made by notching a width of 39 m/m toward the inside of the gasket frame. Next, a diagonal mesh spacer having the same specifications as that used in Example 1 and having a thickness of 0.56 m/m was used in Example 1.
After cutting in the same manner as in Example 1, it was inserted into a gasket frame in the same manner as in Example 1. Next, a 0.5 m/m unvulcanized natural rubber sheet was molded in the same manner as in Example 1, and then 500 m/m x length 700
It was cut into a size of m/m. Furthermore, this unvulcanized natural rubber is made so that its outer dimensions are 1 m/m larger around the entire circumference than the outer dimensions of the previously cut spacer, and 5 m/m/m larger than the outer dimensions of the previously cut spacer.
It was punched out into a shape as shown in Figure 5 with a width of m. (When overlapped with the spacer, an overlapping area of 4 m/m width is created around the entire circumference.) Next, apply glue to the cross section of the entire inner circumference of the gasket frame that was previously manufactured and the spacer has been inserted inside. Next, fit the unvulcanized natural rubber punched into the shape shown in Figure 5 into the inside of the rubber, and lightly press it with your hands.
The cross sections of both were adhered and placed on the spacer. Further, molding and vulcanization were performed in the same manner as in Example 1 to integrate the entire circumference of the gasket frame, the waterway and the current-carrying part spacer, resulting in 7 waterways with a liquid flow width of 26m/m and a thickness of 0.5m/m. We made 300 gaskets for electrodialysis tanks with an effective current-carrying area of 19.6 ^dm2 . The average thickness of the vulcanized portion of the unvulcanized natural rubber in the finished gasket was 0.53 m/m. The completed gasket is shown in Figure 6. In FIG. 6, 11 is the gasket body, 12 is a one-piece spacer that is integrated with the gasket and the Shiodo energizing part, 13 is a communication hole for the concentrated liquid flow and diluted liquid flow, and 14
indicates the vulcanized part of unvulcanized natural rubber. It was assembled in the same manner as in Example 1 using the gasket prepared by the above method and the same type of membrane as in Example 1. It took two people 8 hours to assemble. Then, in the same manner as in Example 1, leakage outside the tank was "0".
When the fastening pressure and tank leak were measured, they were 1.8 Kg/cm ² G and 2 c.c./min/room, respectively. Furthermore, when the limiting current density was measured in the same manner as in Example 1, it was 0.52 A/dm ² . In addition, operation was carried out for 10 days in the same manner as in Example 1, and the average desalination capacity was 3.2 m ³ /Hr. Thereafter, disassembly-reassembly-operation for 10 days was repeated three times in the same manner as in Example 1.
The results were as follows.

[Table] After further 30 days of operation, the critical current density was measured.
It remained unchanged at 0.52A/ ^dm2 . Example 3 1m/ of the same specifications as used in Examples 1 and 2
A gasket frame with a notch having the same shape and dimensions as in Example 2 was made using the same method as in Example 2 using a rubber sheet with a thickness of m. Next, the thickness is 1.2m/m, and the mesh pitch is 5m/m vertically.
A diagonal mesh spacer made of polypropylene measuring 3 m/m x 3 m/m in shore hardness and having a shore hardness of 100 degrees was cut into the same shape and size using the same method as in Example 2. Furthermore, an unvulcanized natural rubber sheet with a thickness of 0.5 m/m was molded using the same method as in Example 2, and then Example 2
It was punched out in the same shape and size using the same method. Next, this punched unvulcanized natural rubber was strongly pressed onto the front and back sides of the previously cut spacer so that it protruded 1 m/m from the outside dimension over the entire circumference of the spacer, forming a sandwich shape as shown in Figure 7. . 7th
In the figure, 15 indicates unvulcanized natural rubber, and 16 indicates a spacer. Next, apply glue to the inside cross section of the notch of the gasket frame with the notch that was made earlier, and then fit a sandwich of unvulcanized natural rubber and a spacer to the shape, and attach the gasket frame to the unvulcanized gasket frame. I attached the natural rubber by lightly butting it together. Next, molding and vulcanization were performed in the same manner as in Example 2 to integrate the entire circumference of the gasket frame, the waterway and the current-carrying part spacer, and there were 7 waterways with a liquid flow width of 26 m/m.
We made 300 gaskets for electrodialysis tanks with a thickness of 1m/m and an effective current-carrying area of ^19.6dm2 . The average thickness of the vulcanized portion of the unvulcanized natural rubber in the finished gasket was 1.05 m/m. Using the gasket made by the above method and the same type of membrane as used in Example 1, it was assembled in the same manner as in Example 1. It took two people 8 hours to assemble. Then, in the same manner as in Example 1, leakage outside the tank was "0".
When the fastening pressure was measured, it was 1.2 kg/cm ² G per effective current-carrying area, and when the leakage inside the tank was measured, it was 1 c.c./min/chamber. Furthermore, when the limiting current density was measured in the same manner as in Example 1, it was 0.57 A/dm ² . Subsequently, the average desalination capacity when operated for 10 days at a current density of 80% of this critical current density was 3.4 m ² /Hr. Thereafter, disassembly-reassembly-operation for 10 days was repeated three times in the same manner as in Example 1. The results were as follows.

[Table] Furthermore, when the limiting current density was measured after 30 days of operation, it remained unchanged at 0.56 A/dm ² . Comparative example 1 0.75m/m with the same composition as that used in Example 1
After cutting a thick rubber sheet into strips with a width of 35 m/m x length of 693 m/m and a width of 72 m/m x length of 351 m/m at a number ratio of 1:1, the area was cut in the same manner as in Example 1.
I made a ^19.6dm2 picture frame gasket frame. Next, a notch with a width of 39 m/m and a diameter of 22 m/m as in Example 2 was made.
I made a gasket frame with a total of 7 M holes on the top and bottom. Next, we prepared a sample with the same specifications as that used in Example 1.
0.8m/m thick diagonal mesh spacer, width 37m/
It was cut to a length of 44 m/m. A hole with a diameter of 22 m/m centered at the center of the width of this spacer and 25.5 m/m from the inside in the length direction was previously drilled. Furthermore, place this spacer into the notch part of the gasket frame made earlier, one on each side and depth.
It was inserted with a gap of m/m. Next, an unvulcanized natural rubber sheet with a thickness of 0.7 m/m was molded in the same manner as in Example 1, and it fit snugly into the gasket frame notch without any gaps and had a thickness of 5 m/m.
It was punched into the shape shown in FIG. 8 with a width of m. Next, after applying glue to the cross section of the notch that does not include the current-carrying part of the gasket frame that was made earlier, that is, the cross section of the channel, lightly poke this part and the previously punched unvulcanized natural rubber by hand. I placed it on the spacer while gluing it. Furthermore, the gasket frame and the Shiodome spacer were integrated by molding and vulcanization in the same manner as in Example 1, and 300 gaskets for an electrodialysis tank having 7 Shiodome with a liquid flow width of 26 m/m were made. . The average thickness of the part of the finished gasket where the unvulcanized natural rubber was vulcanized was 0.82 m/m. The shape of the completed gasket is shown in Figure 9.
In Fig. 9, 17 is the gasket body, 18 is a spacer embedded in unvulcanized natural rubber, and vulcanized.
The hole 19, which is integrated with the gasket frame, indicates a communication hole for the flow of the diluted and concentrated liquid. Insert a 0.8 m/m thick diagonal mesh spacer made of polyethylene for the current-carrying part into the current-carrying part of the gasket prepared by the above method so as not to get on the gasket.
Using the thus prepared gasket and the same type of membrane as used in Example 1, it was assembled in the same manner as in Example 1. It took two people 14 hours to assemble. Then, in the same manner as in Example 1, leakage outside the tank was "0".
When we measured the fastening pressure, tank leakage, and critical current density, they were 1.8Kg/cm ² G and 2c.c./, respectively.
It was 0.51A/ ^dm2 . In addition, operation was carried out for 10 days in the same manner as in Example 1, and the average desalination capacity was 3.3 m ³ /Hr. After dismantling it, there was no deformation of the gasket. Furthermore, as in Example 1, disassembly-reassembly-operation for 10 days was carried out 3 times.
Repeatedly. The results were as follows.

[Table] After the first disassembly, leakage outside the tank did not stop even after tightening to 5 kg/cm ² , so when I disassembled it and examined it, I found that the 18th dilution spacer from the anode side was partially overlapping the gasket. After this was corrected and reassembled, the leak outside the tank became "0" at a fastening pressure of 1.7 Kg/cm ² G.
In other words, the above values are after disassembly and rework. When the critical current density was measured after 30 days of operation after the above operation, it remained unchanged at 0.51 A/dm ² . Comparative Example 2 0.37m/m with the same composition and temperature as Example 1
After molding a thick unvulcanized natural rubber sheet, the width is 35 mm.
m/m x length 693m/m and width 72m/m x length 351m/m
The material was cut into strips at a number ratio of 1:1. Next, a picture frame-shaped gasket frame having an area of 19.6 dm ² was made using adhesive in the same manner as in Example 1. Furthermore, 600 gasket frames with notches having the same shape and dimensions as in Example 2 were made using the same method as in Example 2. Next, the thickness is 0.8mm compared to that used in Example 1.
A diagonal mesh spacer with the same specifications except that
The previously made 0.37 m/m thick unvulcanized natural rubber gasket frame was cut to a width of 3 m/m around the entire circumference of the notch, including the central conductive part, and then placed on this and pressed firmly. Next, after applying a thin layer of glue to the top of the gasket frame with this spacer on it,
Another 0.37m/m thick unvulcanized natural rubber gasket frame that had been made earlier was pasted together, aligning the 22m/m diameter hole in both parts. Furthermore, when forming the gasket, place 4 or 3 holes at the center of the width of the notch spacer, which will become the channel, so that it is in line with the center of the 22m/m diameter holes of the 3 or 4 holes in the gasket frame. diameter 22m/m
I made a hole in it. Then, molding and vulcanization were performed in the same manner as in Example 1 to integrate the entire circumference of the gasket frame and the spacer, resulting in an effective current-carrying area of 19.6 dm ² with 7 channels with a liquid passage width of 26 m/m.
We made 300 gaskets for electrodialysis tanks. The average thickness of the finished gasket is 0.78m/m
However, there was a lot of variation, and the minimum part was 0.60 m/m,
The maximum temperature was 0.98m/m. In particular, the thickness of the area where the spacer was embedded became thicker and became thinner towards the outer edge of the gasket. The shape of the completed gasket is shown in Figure 10.
Reference numeral 20 indicates the gasket body, 21 indicates a spacer having a width of 3 m/m from the gasket frame notch and is integrated with the gasket frame around the entire circumference, and 22 indicates a communication hole for the flow of diluted and concentrated liquid. The gasket made by the above method was assembled with a membrane in the same manner as in Example 2, and leakage outside the tank was confirmed, but there was a lot of leakage outside the tank from between the gaskets.
Even though the hydraulic press was tightened to a tightening pressure of 20 kg/cm ² G, the leak outside the tank could not be stopped. Comparative Example 3 300 gaskets for an electrodialysis tank were manufactured in exactly the same manner as in Example 1, except that adhesive was not applied to the cross section of the gasket cutout. The average thickness of the vulcanized and fixed parts of these 300 gaskets is 0.60m/
It was m. However, 40 of them had creases in some of the spacers near the fixed part of the gasket. This gasket was assembled in the same manner as in Example 1, and the pressure of the hydraulic press at which leakage outside the tank became "0" was measured, and it was found to be 4 kg/cm ² G per effective current-carrying area.
It was hot. Furthermore, when the leak in the tank was measured, it was 15 c.c. per minute per chamber, which was five times higher than that in Example 1. After disassembling the membrane and observing the ion exchange membrane and gasket, it was discovered that a pinhole, a fatal defect, had occurred at the part of the ion exchange membrane where the creases of the spacer hit. The results are summarized in Table 1 in order to make the comparison between the above examples and comparative examples easier to understand.

【table】

【table】 [Brief explanation of drawings]

FIG. 1 shows a picture frame-shaped gasket frame in which two types of strips obtained by cutting a sheet are glued together along the broken lines, and FIG. 2 shows a notched gasket frame obtained by cutting the picture frame-shaped gasket frame. 1... Gasket frame body, 2... Communication hole for diluted liquid flow and concentrated liquid flow. FIG. 3 shows a diagonal mesh spacer to be inserted into the notched gasket frame. 3... Spacer main body, 4... Shiodome section, 5... Communication hole for diluted liquid flow and concentrated liquid flow. Figure 4 shows a gasket by vulcanizing and molding the spacer shown in Figure 3 with unvulcanized natural rubber embedded in its ends and vulcanizing and molding it with a hot press on two opposing sides of the current-carrying part of the gasket frame shown in Figure 2. The gasket is shown integrated with the frame. 6... Gasket body, 7... Spacer, 8... Part where the spacer is embedded in unvulcanized natural rubber and vulcanized to integrate with the gasket frame, 9... Communication hole for diluted liquid flow and concentrated liquid flow. Figure 5 shows unvulcanized natural rubber punched out to be inserted inside the gasket frame with a notch, and Figure 6 shows spacers for the passageways and current-carrying parts embedded in unvulcanized natural rubber around the entire circumference and cured. This figure shows a gasket molded with sulfur and integrated with the gasket frame. 11...Gasket body, 12...Spacer, 1
3... Diluted liquid flow and concentrated liquid flow communication holes, 14... Portion where unvulcanized natural rubber is vulcanized. FIG. 7 shows a pressed product of unvulcanized natural rubber and a spacer obtained by punching unvulcanized natural rubber into the shape shown in FIG. 5 and then strongly pressing it against both sides of the spacer. 15...Unvulcanized natural rubber, 16... Spacer. Figure 8 shows unvulcanized natural rubber punched out to fit into the groove part of the gasket frame, and Figure 9 shows the edge of the spacer in the groove part embedded in unvulcanized natural rubber.
This figure shows a gasket that has been vulcanized and molded using a hot press and integrated with the gasket frame. 17...Gasket body, 18...Shiodo where the end of the spacer is embedded in unvulcanized natural rubber and vulcanized and molded to be integrated with the gasket frame, 19...Diluted liquid flow and concentrated liquid flow communication holes. Figure 10 shows a spacer with a width narrower than the current-carrying part being glued with two sheets of unvulcanized natural rubber coated with glue, and then vulcanized and molded using a hot press to completely bond the gasket frame and spacer. The gasket is shown integrated around the circumference. 20...Gasket body, 21...Spacer wider than the current-carrying part and integrated with the gasket frame around the entire circumference, 22...Diluted liquid flow and concentrated liquid flow communication holes.

Claims (1)

[Claims] 1. A gasket frame member made of a vulcanized rubber sheet is provided with a current-carrying part notch, and glue is applied to at least a part of the cross section of each of at least two opposing sides of the notch, and a current-carrying part spacer having a width narrower than the notch is formed. 0.5mm to 20mm from the notch cross section so that it does not touch the adhesive.
Place it in the notch keeping a gap of mm, place unvulcanized rubber in the gap between the adhesive and the current-carrying part spacer, and in a part including the periphery of the current-carrying part spacer, and then vulcanize it to fix it. At least a part of each of at least two opposing sides of the current-carrying part notch and at least a part of the current-carrying part spacer are formed of vulcanized rubber, and are made of adhesive and vulcanized rubber for fixation. A method for manufacturing a gasket for an electrodialysis tank that is fixed and integrated using a gasket.