JPH0732850B2 - Electrode compound diaphragm of electroosmotic dewatering machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a device for improving the degree of dehydration through electroosmosis by direct current application while pressing and dehydrating a liquid to be dehydrated such as sewage sludge by pressurization. In particular, it relates to an improved structure of a squeezing diaphragm in which electrodes are combined for use in a filter press type electroosmotic dewatering machine.

(Prior Art) A filter press type electroosmotic dewatering machine is disclosed in, for example, Japanese Patent Application Laid-Open Nos. 62-125810, -125811 and -12.
No. 5812 is disclosed. FIGS. 6 (a), (b) and (c) show the basic structure of this type of dehydrator and the outline of its operating steps.

At the stage of FIG. 6 (a), the filter frames (a) and (a) of the filter press are sandwiched between the filter cloths (b) and (b) and the diaphragm (c) to be tightened to remove the sludge of the liquid to be dehydrated. From the stock solution inlet (d), a stock solution pump is pressed between the filter cloths, and the filtered water that has passed through the filter cloth is discharged from the filtered water outlet (e) for primary dehydration. At the stage of FIG. 6 (b), the diaphragm (c)
The squeezing pressure is introduced to the back side to expand it to the front side, and the water in the solidified sludge cake is squeezed for secondary dehydration. At the latter stage of this squeezing dehydration, a direct current is applied between the diaphragm-side electrode (f) and the paired electrode (f ') in the filter chamber to further promote dehydration by the electroosmotic dehydration action and perform tertiary dehydration. Then, as shown in FIG. 6 (c), the filter frames (a) (a)
The open filter cloths (b) and (b) are pulled down and the final dehydrated cake (g) is taken out of the machine.

In the mechanical dehydration secondary dehydration described above, the water content of the dehydrated cake is
The limit is to reach 80-85%, and the dehydration effect hardly increases even if the pressure and time are increased. On the other hand, when squeezing and dehydrating together with electro-osmosis by applying a direct current for 15 minutes at 40 V during squeezing and dehydrating, the water content decreases to 50%, and the dehydrated cake volume can be significantly reduced.

As described above, the electrode of the electroosmotic dehydrator is consumed by an electrochemical action due to direct current application, and receives a strong mechanical action force due to squeezing from the integrally connected diaphragm, so that the conventional stainless steel, nickel steel, Electrodes of various materials and structures such as platinum-coated titanium plates and carbon sintered plates have been proposed and used.

(Problems to be Solved by the Invention) If the electrode integrally connected to the diaphragm of the electroosmotic dehydrator is made of a metal plate, it can have an advantageous structure in that it has a large bending strength. There is a weakness. Electrodes such as carbon sintered plates need to be made of a material that is advantageous for electroosmotic action.Because they are made of a special carbon material, they are generally brittle and do not deform. However, if the split electrode is attached to a flexible diaphragm, it is difficult to evenly energize each split electrode, individual reinforcement structure, complicated mounting structure, difficult to secure water passage through electrode, electrode There is a weakness in that it is easily affected by the reaction.

It is an object of the present invention to create an improved structure of an electrode composite diaphragm of an electroosmotic dewatering machine in which these weak points of the prior art are eliminated or alleviated.

(Means for Solving the Problem) In the present invention, the above-mentioned problem is, as an electrode composite diaphragm of a filter press type electroosmotic dewatering machine, a flexible diaphragm substrate and an electrode plate attached to the surface side thereof. The electrode plate is composed of independent split electrode plates, and the diaphragm substrate is embedded in the central region corresponding to the split electrode plate group and is reinforced by the metal core, and each split electrode and the metal core are provided on the electrode side. It is achieved by forming a composite structure in which the regions other than exposing the respective power supply plates for electrically connecting are electrically insulating and corrosion resistant coatings.

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

(I) Since the diaphragm substrate has a peripheral region other than the central region where the metal core is present, since it has a film structure of a flexible material of the substrate,
It moves to the front side by the pressing pressure used on the back side and expands to perform the original pressing action.

(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 back side of them, and each split electrode plate is prevented from being subjected to a large bending force due to the squeezing pressure. Therefore, the electrode is less likely to be damaged.

(III) Energization to each divided electrode plate is performed by pressing each divided electrode plate by pressing force to each corresponding power feeding plate exposed on the surface side through the metal core, If electricity is applied, an even energization state can be obtained for each divided electrode plate. Even with the divided electrode structure, it is not necessary to establish electrical connection between them.

(IV) Since the metal core in the diaphragm base is entirely covered with an insulating and corrosion-resistant coating except for the power supply plate to be circumferentially sealed, an acid generated on the surface of the electrode during the electrolytic reaction,
Completely corrosion resistant protection against alkali.

(V) Since the individual divided electrodes are in close contact with the power feeding plate and can be connected by a simple stop screw, the divided electrode plate can be easily attached / detached or replaced.

(Example) Hereinafter, the electrode composite diaphragm of the electroosmotic dewatering machine of the present invention will be specifically described with reference to the examples shown in FIGS.

FIG. 1 is a perspective view of a unit electrode composite diaphragm of an embodiment of the present invention as seen from the front side. The diaphragm of this composite structure corresponds to a composite of the diaphragm (c) and the electrode (f) of the filter press type dewatering machine shown in FIG. 6, and includes a filter frame (a) and a filter cloth (b). , Paired electrodes (f ') cooperate in a manner similar to that described for FIG. Therefore, it is composed 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 electrode plates (2A). 1), only one of them is shown in the attached state attached to the front surface side of the substrate (1).

The diaphragm substrate (1) has the same outer shape as the mounting seat of the rectangular frame-shaped filter frame (a), and its outer peripheral edge portion (1a) (see FIG. 2).
And attach it closely. The area inside the outer peripheral edge (1a) forms a filter chamber. A thin flexible film portion (1c) is formed at a substantially constant interval between the central region (1b) corresponding to the divided electrode plate (2A) group and the outer peripheral edge portion (1a), and the substrate (1) The squeezing pressure introduced between the filter frame (b) and the other back-to-back substrate on the back side of the substrate causes the portion (1c) to bend and the central region (1b) to move forward, resulting in a split electrode plate ( 2A) also moves forward and squeezes the sludge introduced through the stock solution inlet (1d) between the filter cloths (b) and (b). The sewage that has passed through the filter cloth (b) passes through the through holes (2a) of the split electrode plate (2A), and the central area (1
The liquid passage (1e ′) in the valley between the protrusions (1e) of b), the liquid passage (1f ′) in the valley between the protrusions (1f) of the flexible membrane (1c), and the outer peripheral edge (1a) ), It is designed to flow out of the machine through the drainage port (1g).

In the present invention, since the group of four divided electrode plates (2A) is simultaneously reinforced against the squeezing force, in the corresponding central region (1b) of the diaphragm substrate (1), iron, titanium, aluminum or the like having relatively high conductivity is used. Use a good metal plate metal core (3) for the second
As shown in FIG. 5 to FIG. When the metal core (3) is thin and the reinforcing action against a large squeezing force is not sufficient, as shown in FIG. 2, a thick reinforcing plate (4) such as polypropylene is attached to the back surface of the substrate. Then, the feeding cable (6) from the DC power source is connected to the stud (5) protruding from the metal core (3) through the substrate (1) and the reinforcing plate (4) to the rear side by the lock nut (7).

On the front side of the metal core (3), a power supply plate (8) made of copper or stainless steel for electrically connecting it to the divided electrode plate (2A) is distributed and arranged at a position corresponding to each divided electrode plate. Then, attach it with the sinking screw (9) made of stainless steel.
As shown in FIG. 1, the power feeding plate (8) is arranged at a position corresponding to the inner side of the four sides of each divided electrode plate (2A). This is the squeezing pressure applied to the divided electrode plate via the power feeding plate. This is to reduce the bending force caused by the bending and to evenly energize the divided electrode plates.

The front area of the metal core (3) other than the power supply plate (8) is
The back surface of the base body (1) and the flexible film portion (1c) are continuously covered with an insulating and corrosion-resistant front surface coating (1A) made of rubber or the like,
Only the power feed plate (8) is exposed. The projections (1e) are distributed and formed on the electric surface coating (1A), and the divided electrode plate (2A) is brought into contact with the back surface of the divided electrode plate (2A) to feed the feeding plate (8).
Along with supporting from the back all over.

As shown in FIGS. 3 and 4, the division electrode plate (2A) is attached to the diaphragm substrate (1) by a thin insulating sheet (10) such as polyvinyl chloride in the attachment recess (2b).
And lay it in and fit it into the power supply plate (8) with a plastic screw (11) penetrating therethrough. This attachment can be done with one touch, and the worn 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, the periphery of the power supply plate (8) is surrounded by a rubber annular portion (1h) slightly protruding from the front surface coating (1A). This protrusion amount is crushed by attachment of the split electrode plate (2A) and squeezing pressure so as to be flush with each other, so that the power supply plate (8) is sealed from the surroundings and electric contact between the power supply plate and the split electrode plate is ensured. Done

(Effects of the Invention) As described above, according to the present invention, as a compression diaphragm with electrodes of an electroosmotic compression dehydrator, uniform compression pressure can be applied to sludge, and the electrode plate is divided into small areas against the compression pressure. Since each independent split electrode plate bears the split squeezing pressure evenly, strength is maintained and damage does not occur, the current paths to the split electrode plates are simple and short, uniform electrode current is conducted, and electroosmotic dehydration is performed. Corrosion-resistant environment caused by the above is protected against corrosion, and it is possible to obtain effects such as easy attachment and replacement of the divided electrode plates.

[Brief description of drawings]

FIG. 1 is a perspective view showing an electrode composite diaphragm of an electroosmotic dewatering machine according to an embodiment of the present invention in a state where a partially divided electrode plate is removed from the front side, and FIG. 2 is a cross-sectional view of an end showing a power supply connection thereof, FIG. 3 is a sectional view of an end portion showing the attachment of the divided electrode plate, FIG. 4 is a partially enlarged sectional view of the same, FIG. 5 is a sectional view of a power feeding plate portion of a diaphragm substrate before assembly, and FIG. ) Is a vertical side view showing the basic structure and one operation stage of a filter press type electroosmotic dehydrator, FIG. 6 (b) is a vertical side view of the different operation stage, and FIG. 6 (c) is further different. It is a vertical side view of an operation stage. (1) …… diaphragm substrate, (1A) …… front coating,
(1a) …… Outer peripheral part, (1b) …… Central region, (1c) ……
Flexible membrane, (1d) …… undiluted solution mouth, (1e) (1f) …… protrusion,
(1e ') (1f') ... liquid passage, (1g) ... drainage port, (1
h) ...... annular part, (2) ...... electrode plate, (2A) ...... split electrode plate, (2a) ...... through hole, (2b) ...... mounting recess, (3)
…… Metal core, (4) …… Reinforcement plate, (5) …… Implant bolt, (6) …… Power supply cable, (7) …… Lock nut,
(8) ...... power supply plate, (9) ...... sinking screw, (10) ...... sheet, (11) ...... stop screw, (a) ...... filter frame, (b) ...
... filter cloth, (c) ... diaphragm, (d) ... undiluted solution inlet, (e) ... filtered water outlet, (f) (f ') ... electrode,
(G) …… Dehydrated cake.

Claims (1)

[Claims] 1. An electrode composite diaphragm of a filter press type electroosmotic dewatering machine, which comprises a flexible diaphragm substrate and an electrode plate attached to the surface side thereof, and the electrode plates are formed by independent split electrode plates. The area other than the area where the diaphragm substrate is configured and the central area corresponding to the divided electrode plate group is embedded and reinforced by the metal core to expose each power supply plate electrically connecting each divided electrode and the metal core to the electrode side. An electrode composite diaphragm for an electroosmotic dewatering machine, characterized by being coated with an insulating and corrosion-resistant coating.