JPH02111410A - Electrode composite diaphragm of electroosmotic press dehydrator - Google Patents

Abstract

PURPOSE:To reduce the breakage of an electrode by collectively reinforcing even a split electrode with the metallic core of a diaphragm base body in contact with the rear of the electrode, and preventing the bending of each sectional electrode plate due to the pressing force. CONSTITUTION:The dehydrator consists of a flexible diaphragm base plate 1 and an electrode plate 2 on the surface of the base plate 1. The electrode plate 2 is formed with independent sectional electrode plates 2A, and the central region 1b corresponding to a group of the sectional electrode plates 2A of the base plate 1 is reinforced by the embedded metallic core 3. On the electrode side, the region other than the part where each feeder plate 8 for connecting each sectional electrode 2A and the metallic core 3 is exposed is covered with an insulating and corrosion-resistant coating film 1A. As a result, the electrode is hardly broken, a uniform current can be applied between the electrodes, and the diaphragm can be protected from the corrosive environment formed by electroosmotic dehydration.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention aims at increasing the degree of dehydration by electroosmotic action by applying direct current to a liquid to be dehydrated, such as sewage sludge, while compressing and dehydrating it under pressure. Pressing die A combined with electrodes used in a device, especially a filter press type electroosmotic press dehydrator
・Regarding the improved structure of the flam.

(Prior art) A filter press type electroosmotic press dehydrator is disclosed in, for example, Japanese Patent Application Laid-Open No. 62-125810 and No. 125 of the same patent application.
No. 811, No. 125812, etc. Figures 6(a), 6(b) and 6(c) schematically show the basic configuration and operating steps of this type of dehydrator.

At the stage shown in Figure 6 (a), the filter frame (a) of the filter press is
) (a) between which the filter cloth (b) (b) and the diaphragm (
C) is clamped and tightened, the sludge of the liquid to be dewatered is compressed between the filter cloths from the raw solution inlet (d) by the raw solution pump, and the filtrate that has passed through the filter cloth is discharged from the filtrate outlet (e). Perform primary dehydration. In the stage shown in FIG. 6(b), squeezing pressure is introduced to the back side of the diaphragm (C) to expand it to the front side, and further water in the solidified sludge cake is squeezed out for secondary dehydration. At the latter stage of this pressure 1 dehydration, a direct current is applied between the electrode on the diaphragm side ('') in the filter chamber and the opposite electrode ('') to further promote dehydration through electroosmotic dehydration, resulting in tertiary dehydration. Then, as shown in Figure 6 (c), open the filter frame (a) and pull down the filter cloth (b) to remove the final dehydrated cake (g).
Take it out of the machine.

In the above-mentioned secondary dehydration using mechanical pressure, the moisture content of the dehydrated cake can only reach about 80 to 85%, and the dehydration effect hardly improves even if the pressure and time are increased. On the other hand, if the press dehydration is performed in combination with electroosmosis by applying a direct current at 40 V for 15 minutes during press dehydration, the water content can be reduced to 50% and the volume of the dehydration cage can be significantly reduced.

In this way, the electrodes of an electroosmotic dehydrator are not only worn out by the electrochemical action caused by direct current, but also receive strong mechanical action from the compression from the diaphragm, which is connected to the body. Electrodes of various materials and structures have been proposed and used, including steel, platinum-coated titanium, carbon sintered plates, etc.

(Problems to be Solved by the Invention) If the electrodes that are integrally connected to the diaphragm of an electroosmotic dehydrator are made of metal plates, they can have an advantageous structure in terms of high bending strength, but they have different structures in terms of electrochemical action. There are weaknesses. The electrode, such as a carbon sintered plate, must be made of a material that is advantageous for electroosmotic action, and since it is made of a special carbon material, it is generally brittle and does not deform, and for strength reasons, it will receive a large amount of pressure unless it has a split structure. However, if the split electrode is attached to a flexible diaphragm, it will be difficult to apply electricity evenly to each split electrode, the individual reinforcement structure will be complicated, the mounting structure will be complicated, it will be difficult to secure a water passage through the electrode, and the electrode will be damaged. It has weaknesses in that it is easily influenced by reactions.

An object of the present invention is to create an improved structure of an electrode composite diaphragm for an electroosmotic press-dehydrator in which these weaknesses of the prior art are eliminated or alleviated.

(Means for Solving the Problem) In the present invention, as an electrode composite diaphragm of a filter press type electroosmotic press dehydrator, an electrode plate attached to a surface side of a flexible diaphragm substrate is provided. The electrode plate is composed of each independent divided electrode plate, and the diaphragm substrate is reinforced with an embedded metal core in the center area corresponding to the divided electrode plate group, and the electrode side is made up of metal (each divided type). This is achieved by forming a composite structure in which areas other than the exposed areas of each power supply plate electrically connected to the core are covered with an insulating and corrosion-resistant coating.

(Function) In the present invention, the problems of the prior art are solved by the following functions.

([) The circumferential area of the diaphragm base other than the central area where the metal core exists is made of a flexible material, so it moves to the front side and expands due to the squeezing pressure acting on the back side. Performs the squeezing action of

(II) Even if the electrodes are divided, they are collectively reinforced by the metal core of the diaphragm base that is in contact with the rear side, and each divided electrode plate is prevented from being subjected to large bending force due to squeezing pressure. Therefore, damage to the electrodes is less likely to occur.

(III) Electricity is applied to each divided electrode plate by pressing each divided electrode plate into contact with each corresponding power supply plate exposed on the surface side through the metal core, so that a part of the metal core is When energized, a uniform energization state can be obtained for each divided electrode plate. Even with a split electrode structure, there is no need for electrical connection between them.

(IV) The metal core of the diaphragm base is completely covered with an insulating and corrosion-resistant coating, except for the power supply plate that is sealed around the periphery, so it is completely corrosion-resistant against acids and alkalis generated on the surface of the electrode during electrolytic reactions. protected.

(V) Since the individual divided electrodes are closely connected to the power supply plate and can be connected with a simple set screw, the divided electrode plates can be easily attached/detached and replaced.

(Example) Hereinafter, the electrode composite diaphragm of the electroosmotic press-dehydrator of the present invention will be specifically described with reference to Examples shown in FIGS. 1 to 5.

FIG. 1 is a perspective view of one unit of an electrode composite diaphragm according to an embodiment of the present invention, viewed from the front side. This composite structure diaphragm corresponds to the composite of the diaphragm (C) and electrode (f) of the filter press type compressor dehydrator shown in FIG. 6, and includes a filter frame (a), a filter cloth (b) , and the counter electrode (f') cooperate in the same manner as described with respect to FIG.

Therefore, it consists of a diaphragm substrate (1) made of a flexible material such as natural rubber or neoprene rubber, and an electrode plate (2). In this example, the electrode plate (2) is divided into four independent divided electrode plates (2A ), and only one of them is the substrate (1
) is shown attached to the front side.

The diaphragm 1 substrate (1) has the same external shape as the mounting seat of the rectangular filter frame (a), and is attached to it in close contact with its outer peripheral edge (la) (see FIG. 2). Outer periphery (la)
The area within forms the filter chamber. Thin flexible membrane portions (1c) are formed at approximately regular intervals between the central region (1b) corresponding to the group of divided electrode plates (28) and the outer peripheral edge (la), and the substrate (1 ) on the back side of this part (lc
), the central region (1b) moves forward, and the divided electrode plate (
2A) move forward together, and the stock solution opening (
Squeezing the sludge introduced through 1d). Filter cloth (b)
The wastewater that has permeated through the through holes (2a) of the divided electrode plate (28)
, the liquid passageway (le') in the valley between the protrusions (1e) in the central region (lb), and the protrusion (1f) in the flexible membrane part (1c).
) and the outer peripheral edge (la) of the valley between
The water flows out of the machine through an inlet (Ig) installed in the machine.

In the present invention, in order to simultaneously reinforce the four divided electrode plate (2A) groups against squeezing force, conductive materials such as iron, titanium, aluminum, etc. A metal core (3) made of a good metal plate,
As shown in FIGS. 2 to 5, it is provided in an embedded state. If the metal core (3) is too thin to provide sufficient reinforcement against large squeezing forces, a thick reinforcing plate (4) made of polypropylene or the like is attached to the back surface of the substrate, as shown in FIG. Then, a power supply cable (6) from a DC power source is connected to a stud bolt (5) that protrudes rearward from the metal core (3) through the substrate (1) and the reinforcing plate (4) using a locking nut (7).

On the front side of the metal core (3), there is a split electrode plate (2A).
Copper or stainless steel power supply plates (8) for electrical connection are distributed and arranged at positions corresponding to each divided electrode plate, and are attached using stainless steel head screws (9). As shown in Figure 1, the power supply plate (8) is placed at a position corresponding to the inner side of each of the four sides of each divided electrode plate (2A), but this is due to the squeezing pressure applied to the divided electrode plate through the power supply plate. This is to reduce the bending force caused by the split electrode plate and to uniformly conduct electricity to the divided electrode plates.

The front area of the metal core (3) other than the power supply plate (8) is
The rear surface of the base body (1) is entirely covered with an insulating and corrosion-resistant front coating (IA) made of rubber or the like that continues to the flexible membrane portion (1c), leaving only the power supply plate (8) exposed. The aforementioned protrusions (1e) are formed in a distributed manner on this front surface film (18), and the divided electrode plate (2^) is in contact with the back surface of the divided electrode plate (2A), and the divided electrode plate (2^) is attached to the entire surface from the back side together with the power supply plate (8). support.

This diaphragm, divided electrode plate (2A) into the substrate (1)
To install it, as shown in Figures 3 and 4, place an insulating sheet 00) made of polyvinyl chloride or the like in the mounting recess (2b), and insert a plastic fixing screw (00) that passes through it.
11) by fitting it into the power supply plate (8). This installation can be done with one touch, and the TFL worn-out split electrode plate can be quickly replaced with a new one.

In order to seal each power supply plate (8), as shown in FIGS. 3 and 5, its periphery is surrounded by a rubber ring (1h) that slightly protrudes from the front surface coating (18).

This amount of protrusion is crushed and flushed by the mounting and squeezing pressure of the divided electrode plate (2^), so the power supply plate (8) is sealed from the surroundings and the current-carrying contact between the power supply plate and the divided electrode plate is prevented. It will definitely be done.

(Effects of the Invention) As described above, according to the present invention, as a squeezing diaphragm with an electrode for an electroosmotic squeezing dehydrator, it is possible to apply squeezing pressure evenly to sludge, and the electrode plate is divided into small areas in response to the squeezing pressure. Since each independent divided electrode plate supports the divided squeezing pressure equally, the strength is maintained and no damage occurs, and the current path to the divided electrode plates is simple and short, and even current is applied between the electrodes, and electroosmotic dehydration is achieved. Effects such as being protected against corrosion from the corrosive environment that occurs and making it possible to easily attach and replace the split electrode plate can be obtained.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an electrode composite diaphragm of an electro-osmotic press dehydrator according to an embodiment of the present invention, as seen from the front side with a partially divided electrode plate removed; FIG. 2 is a sectional view of the end showing the power connection; Fig. 3 is a cross-sectional view of the end showing the attachment of the divided electrode plate, Fig. 4 is a locally enlarged cross-sectional view, Fig. 5 is a cross-sectional view of the power supply plate portion of the diaphragm board before assembly, and Fig. 6 (
A) is a cross-sectional side view showing the basic configuration and one operating stage of a filter press type electroosmotic press-dehydrator, Fig. 6(B) is a vertical sectional side view of the different operating stages, and Fig. 6(C) is the same. FIG. 7 is a longitudinal side view of a further different stage of operation; (1)...Diaphragm substrate, (IA)...Front coating, (la)...Outer peripheral edge, (1b)...Central region, (1c)...Flexible film part, (ld )...Stock solution port, (
le) (If) ”・Protrusion, (le') (lf')・
...Liquid passage, (1g)...Drainage port, (lh)...Annular part, (2)...Electrode plate, (2A)...Divided electrode plate, (2a)...Connection Hole, (2b)...Mounting recess, (
3)...Metal core, (4)...Reinforcement plate, (5)...
Studded bolt, (6)...Power cable, (7)...
- Locking nut, (8)... Power supply plate, (9)... Pillow head screw, 00)... Seat, (11)... Locking screw,
(a)... Filter frame, (b)... Filter cloth, (C)... Diaphragm, (d)... Stock solution inlet, (e)... Filtrate outlet, (f) (f ')...electrode, (2)...dehydrated cake. Figure 3 (a)

Claims (1)

[Claims] The electrode composite diaphragm of the filter press type electroosmotic press dehydrator is composed of a flexible diaphragm substrate and an electrode plate attached to the surface side of the flexible diaphragm substrate, and the electrode plate is composed of independent divided electrode plates, and the diaphragm substrate The central region corresponding to the divided electrode plate group is reinforced with an embedded metal core, and the area other than the exposed power supply plate that electrically connects each divided electrode and the metal core on the electrode side is insulating and corrosion resistant. An electrode composite diaphragm for an electroosmotic press dehydrator, characterized in that it is covered with a film.