JPS60121290A - Structure of dialytic chamber frame in electrodialytic cell - Google Patents

Abstract

PURPOSE:To prevent the leakage of liquid from a tide-way part, and to provide a titled structure enabling the operation at high temps. by fixing a filmy structure having more excellent rigidity and heat resistance than an ion-exchange membrane on both surfaces of a notch at the end part of a dialytic chamber frame to form the tide-way. CONSTITUTION:A dialytic chamber is formed at the central notched part by providing a spacer 8, and a tide-way 7 connecting the dialytic chamber with a communicating hole 6 is formed by a notched part at the end part of the dialytic chamber frame 3 of an electrodialytic cell. The dialytic chamber frame 3 and an ion-exchange membrane are alternately arranged at said notched part at the end part to assemble the electrodialytic cell. At this time, two sheets of a filmy structure 10 having more excellent rigidity and heat resistance than said ion-exchange membrane are fixed. Said filmy structure 10 can be attached in assembling to said notched part at the end part and tightened, or bonded to the notched part at the end part with an adhesive and fixed. A material such as polycarbonate, polyester, PE, PP, polyamide, and vinylidene chloride is used as the filmy structure, and the inside of the tide-way 7 can be watched due to the transparency of the material.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention provides a method for arranging a large number of cation exchange membranes and anion exchange membranes alternately through a dialysis room frame, and forming a membrane at both ends of the membrane group and the dialysis room frame group. The present invention relates to the structure of a dialysis chamber frame in an electrodialysis tank in which a pair of electrode chambers and electrodes are arranged to alternately form demineralization chambers and concentration chambers between membranes to dilute and concentrate electrolytes.

[Background of the invention]

Electrodialysis is a membrane separation technology that utilizes the selective permeation ability of ion exchange membranes, and because of its selective separation ability and energy savings,
It is used in many ways, including salt production by concentrating seawater, freshwater production by desalination, and separation of organic matter and inorganic salts.

An electrodialysis tank has a large number of cation-exchange membranes and anion-exchange membranes stacked alternately through a chamber frame made by cutting out the center of a sheet of rubber, plastic, etc. In order to hold the membranes together, stir the liquid flow, and make the liquid flow uniform, a net-like spacer made of plastic or the like is usually inserted (in some cases, the chamber frame is integrated), and the membrane group, the chamber frame group, and the spacer group are each A pair of electrode chambers and electrodes are provided, and the entire structure can be tightened in the stacking direction.

The development diagram of the dialysis chamber part of the above general electrodialysis tank is shown in Figure 1.
Shown in the figure. In FIG. 1, a dialysis chamber frame 3 is arranged between anion exchange membranes 1 and 2 which are arranged alternately, and a central notch 4 of the dialysis chamber frame 3 is a dialysis chamber (desalination chamber or concentration chamber). room), the above-mentioned spacer 8 is in the dialysis room.
is provided.

Communication holes 5A, 5B, and 6A are provided around the periphery of the dialysis room frame 3.

6B is connected to the dialysis room 4 via progressive stages 7A and 7B. A structure called a distributor is generally inserted within the gradation to ensure a liquid flow path. The water to be treated flows through the electrodialysis tank in the order of communication hole 6A, gradual flow 7A, dialysis chamber 4, measuring path 7B, and communication hole 6B as shown by arrows in FIG. 1, and desalination or concentration of salts is performed. , will be.

The progressive stages 7A and 7B have an important role of distributing and collecting the water to be treated to the dialysis room 4, but due to their structure, they are also very susceptible to liquid leakage.

In the electrodialysis method, there is often a large difference in concentration between desalinated water and concentrated water, which are separated by a single membrane. For example, in seawater desalination, fresh water with a salt concentration of 5001p and salt with a salt concentration of 120 times that amount are used. Concentrated water with a concentration of about 6% flows through the tank, and even a small leak of concentrated water into the fresh water side greatly affects the quality of the fresh water, and even if electricity is applied for a long time, fresh water of less than 500Wn can be obtained. In many cases, this is not possible. Therefore, prevention of liquid leakage in this progressive section is an important issue that affects the mission of the electrodialysis tank.

Various methods have been proposed in the past in order to prevent liquid leakage in such gradual sections. These methods include, for example, the method of narrowing and lengthening the progression (J, 几, WLIl
son: Demineralization byli
:1ectrodialysis, Butterwo
rthsScien fic 1Jul)licati
ons, 1960), a method of refracting the gradual flow (Japanese Patent Publication No. 38-4337), a method of inserting a net etc. as a membrane support U, etc., but the most frequently used method is a method of refracting the gradual flow (herein referred to as a distributor). ).

FIG. 2 shows this method and problems. Second
Figure (2) is a plan view showing the structure of a typical distributor, in which the progressive part 7 of the dialysis room frame 3 has a spacer 8 and a mesh structure (distributor) with horizontal wings resembling a spacer 8.
9 is inserted. The second inversion is different from (2) in that the spacer 8 and the network structure 9 as the membrane support are integrated in the plan view showing the modification 8.l.

However, even with the method of inserting a mesh structure into the gradual part, the second
As shown in the figure (Q), the ion exchange membrane is only supported by a line with a width narrower than the strands of the mesh, and the membrane is usually 0,1
Since it is in the form of a thin sheet of ~0.2w and does not have a large amount of damage, it falls into the progressive part 5 and creates a gap between it and the dialysis room frame 3, and liquid leakage occurs through this gap. That is, mixing of demineralized water and concentrated water occurs.

This phenomenon mainly occurs due to excessive tightening of the chamber frame group, long-time operation, and operation at high temperatures. In particular, in electrodialysis tanks that use membranes that use polyvinyl chloride as the support material (polyvinyl chloride, which has good affinity with ion exchange resins, is often used as the support material for ion exchange membranes for electrodialysis), the dialysis temperature is low. This problem is likely to occur as the temperature rises, and it is quite difficult to operate this type of membrane above 4 CI'.

[Purpose of the invention]

The present invention solves the above-mentioned problems of the conventional electrodialysis tank tideway, and provides a dialysis room frame structure having a progressive electrodialysis tank that is unlikely to cause liquid leakage and also enables high-temperature operation. be.

[Summary of the invention]

The present invention provides at least the dialysis chamber in an end notch of a gold analysis chamber frame that extends between a central notch forming a speckle-deposition chamber and an end notch that communicates with the central notch and forms a gradient. The frame and ion exchange membrane are arranged alternately to form an electrodialysis tank f:! (2) When erected, two film-like structures having better rigidity and heat resistance than the ion exchange membrane are fixed.

[Embodiments of the invention]

Figures 3 to 4 and 5 show examples of the progressive part +11q construction of the present invention.

In FIG. 3, a step 3A is provided on both sides of the dialysis room frame 3, and a film-like structure 10 is fixed to each step.

Regarding the method of fixing the film to the notch (progressive part) of the chamber frame, as long as there are no problems such as the film shifting during assembly or operation of the electrodialysis tank! There is no performance problem for Samurai, and you can simply insert it. In this case, the film is fixed at least at the end notch (gradual portion) of the dialysis chamber frame when the gas dialysis tank is assembled.

In addition, the film is pasted to the end notch (gradual part) of the dialysis room frame with an adhesive or adhesive, or the room frame material has a deformation temperature (or melting point, or glass softening point) higher than that of the film.
In the case where the film is made of polyester and the chamber frame is made of polyethylene, for example, when the film is made of polyester and the chamber frame is made of polyethylene, they can be pressed and fused using a press or the like under heating at an appropriate temperature to be integrated.

FIG. 4 shows another embodiment of the present invention, in which the film-like structure is provided not only in the gradual part and its vicinity, but also completely covers the part that is outside the chamber frame (the communicating hole 6). , excluding the dialysis chamber section 4, which is the current-carrying section].In this method, the dimensions of the film section are small, so the work of adhesion to the gradual section, adhesion, and fusion integration with the chamber frame is necessary. It has the advantage of being easy to move and improving positional stability. Therefore, the film-like structure of the present invention only needs to have a size that ensures at least a progressive portion.

Further, in FIG. 4, a film support 11 is inserted into the progressive portion 7. This further supports the film, which is more rigid and heat resistant than the membrane, and can further ensure the effect of preventing the film from falling. The support material is not particularly limited as long as it supports the film and secures a path for the liquid j11i, but the network structure shown in FIG. 2 can be suitably used.

In FIGS. 3 and 4, a transparent film of polyester, polycarbonate, polyethylene, etc. can also be used. The NA duct has a smaller flow path cross-sectional area than the dialysis chamber, and is the part where blockage of solid matter such as suspended solids is most likely to occur, which is a serious problem in practical use of electrodialyzers. If a transparent film is used in the film-like structure, it is possible to accurately grasp the blockage situation in the dialysis tank through the transparent film when disassembling and cleaning the dialysis tank.

FIG. 5 shows still another example of the present invention, in which the film-like structure 1O is not fixed to the entire progressive periphery, but is partially hardened, and the film-like structure is turned over in the progressive part, and the inside of the progressive part is This makes it easy to clean.

〔Effect of the invention〕

As described above, according to the present invention, since a highly rigid film-like structure is used, liquid leakage, especially liquid leakage caused by falling into the gradual part of the membrane, can be prevented, and the film has high heat resistance. Since a shaped structure is used, it is possible to prevent liquid leakage during high-temperature operation, and stable operation is possible.

[Brief explanation of the drawing]

Figure 1 is a developed perspective view showing the configuration of a dialysis chamber using a conventional electrodialysis tank; Figure 2 is a plan view showing the progressive structure of a conventional dialysis chamber frame; - A cross-sectional view along line A,
The third device is a partial perspective view showing one embodiment of the present invention.
0 is a sectional view taken along line B-B in FIG. 3(2), FIG. 4(a) is a partial perspective view showing another embodiment of the present invention, and FIG.
Figure ■ indicates 01...Cation exchange membrane, 2... in Figure 4 (5).
... Anion exchange membrane, 3... Dialysis room frame, 4... Dialysis room frame center notch (dialysis room), 5A, 5B... Communication hole,
6A, 6B...Communication hole, 7A. 7B... Gradual, 8... Spacer, 9... Distributor, 10... Film-like structure, 11...
・Fill (C no Δ formation (4) (f3) (/1) (B) 11 J'

Claims (1)

[Scope of Claims] 1. At least one of When an electrodialysis tank is assembled by alternately arranging the dialysis chamber frame and the ion exchange membrane, two film-like structures having superior rigidity and heat resistance as the ion exchange membrane are fixed. A dialysis chamber frame structure of an electrodialysis tank characterized by the following. 2. Claim 1 provides that the film-like structure is attached to the end notch and is fixed to the end notch by tightening during assembly of the electrodialysis cell. Characteristic dialysis chamber frame structure of the electrodialysis tank. 3. In item 1, the film-like structure is fixed to the end notch,
- Characteristic dialysis room frame structure of the electrodialysis tank. 4.%W "The dialysis in an electrodialysis tank according to claim 1, wherein the film-like structure is made of polycarbonate, polynistyl, polyethylene, polypropylene, polyamide, or vinylidene chloride. Chamber frame structure. 5. The dialysis chamber frame structure of an electrodialysis tank as set forth in claim 1, wherein the film-like structure is a transparent material. 6. In claim 1 A dialysis chamber frame structure for an electrodialysis tank, characterized in that the front film-like structure is partially fixed to the dialysis chamber frame structure except for all or most of the periphery of the end notch.