JPH0468006B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a filter press type electroosmotic dehydrator equipped with a squeeze diaphragm, and particularly to an improvement in the structure of a squeeze filter plate equipped with an electrode.

(Prior Art) When a direct current is passed through the sludge during the sludge compression and dewatering process, water in the sludge that cannot be dehydrated simply by squeezing moves to the outside due to electroosmosis, thereby promoting dewatering. When electroosmosis is used in combination with a batch-type compressing dehydrator such as a filter press equipped with a compressing diaphragm, it is possible to provide sufficient energization time compared to a continuous compressing dehydrator such as a belt press, thereby eliminating uneven energization during the dehydration process. Since this does not easily occur, effective dehydration treatment can be performed and the water content of the dehydrated cake can be significantly reduced.

For example, sewage sludge that has been preconcentrated to a water content of 95 to 97% by adding a polymer flocculant is fed to a filter press with a pressing diaphragm and dehydrated by pressing at a pressing pressure of 3 kg/cm ² for about 20 minutes. Cake moisture content is 80-85%, no more pressing pressure,
Even if the pressing time is increased, the effect of reducing the moisture content is small, but
If the filter press is equipped with an electrode structure and electroosmotic dehydration is performed by applying a DC voltage of 40 V between the electrode plates during compression dehydration for about 15 minutes, the moisture content of the dehydrated cookie will drop to around 60%. The volume of the dehydrated cake is 1/2 or less compared to that obtained only by pressing and dehydration.

FIG. 1 shows an example of an electroosmotic dehydrator to which the electrode structure of the present invention is applied, and FIG. 2 shows a perspective view of the filter plate framework in a separated and open state. Using these, an overview of this type of dehydrator as a whole will be explained.

A filter frame 5 is interposed between a filter plate 3 and a compressed filter plate 4 between the main plate 1 and the movable plate 2 of the press, and an appropriate number of these sets are interposed and closed by tightening. One electrode plate 6 is fixed to the filter plate 3. This electrode 6 is made of a porous water permeable plate. A filter cloth 7 is hung over the entire surface of both sides of the filter frame 5, and the hollow space thereof is used as a filter chamber 8. A sinterable diaphragm 9 is provided on the compressed filter plate 4, and the other electrode plate 10 is attached to this.

The dehydration operation is performed in the following order. That is, raw sludge is press-fitted into the filter chamber 8 of the filter frame 5 through the raw sludge plate frame through hole 11, and the filtrate that has passed through the filter cloths 7 on both sides is transferred from the filter plate 3 and from the compressed filter plate 4 for filtrate use. Plate frame through hole 1
Discharge to 2a12b. When the filling of the filter chamber with the raw sludge and the filtration by the supply pressure are completed, the supply of the raw sludge is stopped, and compressed air is supplied from the compressed air plate frame through hole 13 to the back of the diaphragm 9 of the compressed filter plate 4. The diaphragm 9 is expanded to compress and dewater the sludge filling the filter chamber. Next, a DC voltage is applied between the electrode plates 6 and 10 to perform electroosmotic dehydration.

An example of a compressed filter plate 4 that requires a diaphragm 9 and an electrode 10 is disclosed in the earlier patent application No. 1969-1960.
12 and 13, and FIG. 5 is a longitudinal sectional side view thereof.

(Problems to be Solved by the Invention) The electroosmotic dehydrator described above has a structure in which the electrode plate 10 on the front side of the diaphragm 9 is fixed to the support plate 15 on the back side by a large number of bolts 14 passing through the diaphragm. When compressed air is supplied to the back of the diaphragm to expand it and perform compression dehydration, the diaphragm elongates, causing a gap between it and the electrode plate 10, causing air leakage from the bolt 14 through-hole, which impairs the compression dehydration effect. It was discovered that there were problems such as the mounting bolts 14 coming off due to repeated operations.

The present invention aims to solve the above problems.

(Means for Solving the Problems) According to the present invention, the above-mentioned object is to separate the diaphragm and the electrode from the electrode structure on the squeeze filter plate side so that they do not interfere with each other, and also so that each of them can perform its original function. This is achieved by making

That is, the electrode structure of the electro-osmotic dehydrator of the present invention is a filter press type electro-osmotic dehydrator equipped with a compression diaphragm.
The present invention is characterized in that the electrode plate of the compressed filter plate having the compressed diaphragm is supported on the filter chamber side so as to be movable back and forth, separated from the compressed diaphragm surface.

(Function) Since the electrode plate on the squeeze filter plate side is not fixed to the diaphragm surface, the problem caused by the elongation of the diaphragm during press dehydration is solved.

(Example) Hereinafter, the electrode structure of the electroosmotic dehydrator of the present invention will be explained in detail with reference to Examples shown in FIGS. 3 and 4. FIG. 3 shows a longitudinal sectional side view of a squeeze filter plate related to the electrode structure of the present invention, and FIG. 4 shows a front view thereof. An example of an electro-osmotic dehydrator to which this compressed filter plate is applied is shown in FIG. 1, and the filter plate framework is shown in FIG. 2, which will be described in detail.

The compressed filter plate of this embodiment of the present invention has compressed diaphragms 9, 9 sandwiched between the central compressed filter plate main body 20 and electrode plate holding frames 21, 21 having hollow holes on both sides, respectively, and is secured by a sinking bolt 22. Fix it. The compressed filter plate main body 20 is provided with a communication hole (not shown) that communicates with the compressed air plate frame through hole 13, and compressed air is introduced from this path to the interface with the diaphragm 9, and the diaphragm 9 expands outward. do.

On each side, a receiving step 23 is formed on the inner edge of the outer surface of the hollow electrode plate holding frame 21, and an elastic support member 24 made of an elastic material such as rubber is stretched over the entire hollow cavity of the electrode plate holding frame. Then, it is clamped to the receiving step part 23 with the presser frame 25 and fixed with the sinking screw 26.
The electrode plate 10 is applied to the front side of the central part of the elastic support member 24 excluding the peripheral part, and the contact plate 27 is applied to the back side.
are applied, and the two are connected by a sinking screw 28 that passes through the elastic support member 24 as well. Electrode plate 10
The elastic support member 24 is provided with water holes 29 that communicate with each other and are distributed over the surface.
7 is in contact with the back of the elastic support member 24 by its protrusion 27a, and most of the other parts are provided with a water passage interval between them and the elastic support member. In this way, the electrode plate 10 is separated from the diaphragm 9 and is supported independently and movably in the front and rear directions on the side of the adjacent filter frame 5 and the filter chamber 8. Electrode plate 10 and conductive member 30 protruding to the outside
A conductive connection is made between the electrode plate 10 and the electrode plate 10 by a sinterable lead wire 31 or the like so as not to hinder the back and forth movement of the electrode plate 10.

In this embodiment, when the raw sludge is injected into the filter chamber 8,
The electrode plate 10 is connected to the diaphragm 9 by the sludge feeding pressure.
The contact plate 27 is pressed against the diaphragm 9 by moving backward to the side, and the filtrate filtered by the filter cloth 7 is transferred to the electrode plate 1.
0, it passes through the water passage hole 29 of the elastic support member 24, passes through the filtrate hole 32 of the electrode holding frame 21, and is discharged through the filtrate plate frame through hole 12b.

Next, compressed air is passed through the through holes 13 to the compressed filter plate main body 2.
When the electrode plate 10 is fed into the gap between the electrode plate 0 and the diaphragm 9 to expand the diaphragm 9, the electrode plate 10 is pushed by the advancing diaphragm 9 and moves in a direction approaching the electrode plate 6. At this time, since there are no bolt holes in the diaphragm 9 facing toward the filter chamber 8, there is no risk of air leakage during compression dewatering.

Of course, electroosmotic dehydration can be performed without any problem by direct current flowing between the electrodes 6 and 10.

In the above embodiment, an elastic support member 24 such as a water-permeable rubber plate is stretched across the entire inside of the electrode plate holding frame 21 as an electrode support member, but instead of this, the peripheral part of the electrode plate 10 and the electrode plate support A structure may be adopted in which the frame 21 is connected to the frame 21 by a band-shaped elastic member. Further, when the moving distance of the electrode plate 10 is short, a bendable hanging member that supports the electrode plate 10 only from above may be used.

Further, the filter plate framework is not limited to the type in which the filter frame 5 is sandwiched between the filter plate 3 and the compressed filter plate 4 as in the above embodiment, but it is also possible to use a dehydrator without a filter frame, for example, a filter plate 3
and the compressed filter plates shown in FIGS. 3 and 4 are arranged alternately, or only these compressed filter plates are arranged,
The electrode structure of the present invention is also applicable to a type of press dehydrator in which raw sludge can be supplied between two filter cloths sandwiched between them.

(Effects of the Invention) As described above, according to the electrode structure of the present invention, the problem of trouble caused by the elongation of the diaphragm during compression dehydration is solved, thereby improving the reliability of this type of filter press type electroosmotic dehydrator. It is also easier to maintain and manage.

[Brief explanation of the drawing]

Fig. 1 is a side view of an example of an electroosmotic dehydrator to which the electrode structure of the present invention is applied, Fig. 2 is a perspective view of the filter plate framework in a separated and open state, and Fig. 3 is an embodiment of the present invention. FIG. 4 is a longitudinal sectional side view of a compressed filter plate in the electrode structure of an electroosmotic dehydrator, FIG. 4 is a half longitudinal front view thereof, and FIG. 5 is a longitudinal sectional side view of the compressed filter plate of the prior art. 1... Main plate, 2... Movable plate, 3... Filter plate, 4...
...Pressed filter plate, 5...Filter frame, 6...Electrode plate, 7...
Filter cloth, 8... Filter chamber, 9... Compressed tire flam, 1
1...Plate frame through holes for raw sludge, 12a, 12b...
Plate frame through hole for filtrate, 13... Plate frame through hole for compressed air, 14... Bolt, 15... Support plate, 20...
Pressing filter plate main body, 21... Electrode plate holding frame, 22...
Bolt, 23... Step portion, 24... Elastic support member, 25... Holding frame, 26... Screw, 27... Backing plate, 27a... Protrusion, 28... Screw, 29... Water hole , 30... Conductive member, 31... Lead wire, 3
2...Filtrate hole.

Claims (1)

[Scope of Claims] 1. In a filter press type electroosmotic dehydrator equipped with a compressed diaphragm, an electrode plate of a compressed filter plate having a compressed diaphragm is supported on the filter chamber side so as to be movable back and forth, separated from the compressed diaphragm surface. An electrode structure of an electroosmotic dehydrator characterized by the following. 2. The electrode structure for an electroosmotic dehydrator according to claim 1, wherein an electrode plate holding frame is fixed to the pressing filter plate, and the electrode plate is supported within the frame via an elastic member. 3. The electrode structure for an electroosmotic dehydrator according to claim 2, wherein the elastic member is a rubber plate having water passage means.