JPH0687925B2 - Electro-osmotic dehydrator electrode - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electrode structure of an electroosmotic dehydrator used for dehydrating sludge generated in a sewage treatment plant or the like.

[Conventional technology]

As a typical example of the above-mentioned electroosmotic dehydrator, a belt press type as shown in FIG. 3 has been conventionally known. In the figure, 1 is a hopper arranged on the sludge supply side, 2 is a conveyor belt which also extends between a pair of rollers 4 along a slurry passage 3, and also serves as a cathode side electrode, 5 is a drive motor for the conveyor belt 2, and 6 The reference numeral 8 designates a press belt which is stretched between a pair of rollers 7 so as to face the belt 2 across the slurry passage 3 and which also serves as an anode side electrode, and 8 designates belts 6 and 2 which also serve as the anode side electrode and the cathode side electrode. It is a DC power supply that applies a voltage to the. For each of the belts 2 and 6, a drain belt made of a conductive material such as a metal having high corrosion resistance or carbon, a caterpillar belt having a degassing groove, or a net belt woven in a mesh shape with a conductive wire material is adopted. ing.

The dehydration action of such an electroosmotic dehydrator is well known, and a voltage is applied to each of the belts 2 and 6 from a power source 8 so that the drive belt 5 is driven by the drive motor 5 so that the slurry passage 3 is conveyed from the hopper 1.
By supplying the sludge 9 to be dehydrated to the sludge, the sludge is sandwiched between the conveyor belt 2 and the press belt 6 in the process of being conveyed from the inlet side to the outlet side in the slurry passage 3. Upon receiving the squeezing force, the electroosmotic action based on the electric field formed between the counter electrodes is applied. Therefore, the water contained in the sludge is positively charged, flows toward the cathode side, and is transmitted through the conveyor belt 2 by the pressing force to be discharged to the outside of the system. As a result, the sludge 9 is dehydrated, and the dehydrated cake 10 is discharged from the outlet of the slurry passage 3. In addition, the gas generated by the electrolysis of the components in the sludge accompanying the electroosmosis is also transmitted through the belts 2 and 6 and is released.

In addition, in order to compensate for the reduced volume of the sludge 9 due to the progress of dehydration in the dehydration step and apply a sufficient squeezing force in the entire slurry passage, at the same time, to obtain a good distribution of electricity to the sludge in the entire slurry passage, In the slurry passage 3, the press belt 6 is inclined with respect to the conveyor belt 2 so that the passage cross section between the electrodes is narrower on the outlet side than on the inlet side. In an actual electro-osmotic dehydrator, the belt spacing is practically 10 mm on the inlet side of the slurry passage 3 and 5 mm on the outlet side in consideration of the increase in the electrical resistance of sludge and the electrical resistance of sludge accompanying the progress of dehydration. It is set to a degree.

On the other hand, as described above, in the actual dehydrator, the interval between the electrode-use belts 2 and 6 that face each other across the slurry passage 3 is set to a narrow interval of about 5 to 10 mm, and thus long-term operation is not possible. If the belts 2 and 6 are loosened due to this, or if the supporting structure on the rollers 4 and 7 side on which the belts 2 and 6 are hung is deflected and the relative positions between the belts are displaced, the belt 6 on the anode side and the cathode side The belt 2 on the side may directly contact with each other to cause an electrical short circuit. Moreover, when such a short circuit occurs due to direct contact between the electrodes, a large current flows intensively in this short circuit section, and normal electroosmotic dehydration cannot be performed.In addition, the belt itself that also acts as an electrode and also acts as an electrode It may cause damage.

As a safety measure for this, conventionally, a large number of ropes 11 made of an insulating material are stretched around the surface of the conveyor belt 2 in the slurry passage as shown in FIG. 4, or the belts 2, 6 are provided as shown in FIG. The filter cloth 12 made of an insulating belt is superposed on the surface of the belt, which ensures the drainage and exhaust gas functions of the belts 2 and 6, and also causes an electrical short circuit when the belts 2 and 6 come into direct contact with each other unexpectedly. We are dealing with it in a way that prevents it from happening.

[Problems to be solved by the invention]

By the way, the conventional structure for preventing short circuit accidents shown in FIGS. 4 and 5 has the following drawbacks. Ie belt
Insulation rope 11 or insulation filter cloth 12 for 2 or 6
In the structure in which is added, since the insulating rope 11 and the insulating filter cloth 12 occupy a part of the interval between the belts defining the slurry passage 3 to cover the electrode surface, the slurry passage 3 is spatially separated. In addition to being limited, the electrical resistance between the electrodes substantially increases and the power consumption required for electroosmotic dehydration increases. Moreover, if the rope, filter cloth, etc. are simply superposed on the belt, the belt, the rope, and the filter cloth may be displaced or biased due to external force during operation, and eventually the belt may fall off. However, the maintenance structure for preventing this is complicated and its maintenance is troublesome.

The present invention has been conceived in view of the above points, and its purpose is not to impair the collection function of wastewater, exhaust gas, and sludge particles accompanying the progress of dehydration in any way, and, moreover, as in the conventional method, the belt between electrodes also serves as a belt. An electro-osmotic dehydrator that can reliably prevent the occurrence of an electrical short even if the counter electrode comes into direct contact due to belt slack, etc. To provide the electrode of.

[Means for solving problems]

In order to solve the above-mentioned problems, according to the present invention, a conductive wire material, a net woven with one warp thread of the insulating wire material and the other as a weft thread, and the conductive wire material is provided at least on the side facing the slurry passage. It shall be woven into the inside of the insulated wire so that it does not stick out to the net surface.

[Action]

With the above structure, the conductive wire is a metal wire having high corrosion resistance, the insulating wire is a synthetic fiber thread, and the belt-shaped device is configured by using the linearly stretched metal wire as the weft thread and the insulating wire as the warp thread. is there.

Therefore, by adopting the above belt-shaped net for the sludge transfer belt that also serves as an electrode and the press belt, even when the belts on the anode side and the cathode side directly contact each other due to slack of the belt during operation, It is possible to prevent the occurrence of an electrical short circuit without the conductive wire materials contacting each other simply by contacting the insulating wire materials forming the net. Further, most of the conductive wire is exposed on the net surface, and in the electroosmotic dehydration step, the exposed portion of the conductive wire and the sludge are brought into contact with each other to sufficiently secure the necessary energization to the sludge. Moreover, this net is woven so that the conductive wire and the insulating wire are integrated, and the conductive wire and the insulating wire are not separated by an external force, and the density of the meshes should be appropriately selected. Can provide good drainage, exhaust gas, and sludge molecule collection functions.

〔Example〕

1 and 2 are a plan view and a sectional view showing the structure of an electrode knitted into a belt-like net according to an embodiment of the present invention, in which 13 is a conductive wire and 14 is an insulating wire, both of which are weft threads. A belt-like net 15 which is a warp and also serves as an electrode is woven.

Here, the example manufactured by the inventor will be described. The conductive wire material 13 serving as the weft thread is made of stainless steel with high corrosion resistance of 0.17 mm.
The twisted wire is made by bundling seven φ fine wires and twisting them. The insulating wire material 14 is a nylon multifilament yarn in which four 14 denier nylon fibers are twisted together and the weft yarn is used. The weaving density of the warp yarns is 31 yarns / in and the warp yarn density is 52 yarns / 1 in.
Was produced.

The net 15 woven in this manner is woven in the center of the net layer so that the conductive wire 13 arranged in a straight line as shown in the cross section of FIG. Insulating wire rods 14 are lined up on the front and back outer surfaces of the net 15, so that the conductive wire rods 13 do not stick out to the net face. The air permeability of this net was 30 cc / cm ² / sec.

Next, the net 15 is used as the conveyor belt 2 and the press belt 6 which also serve as electrodes in the belt press type electroosmotic dehydrator shown in FIG. 3, and the sludge is dehydrated.
While sludge particles are captured on the surface of the net 15 to prevent sludge from leaking, at the same time sufficient drainage and exhaust gas functions are provided for water that has flowed to the electrode surface by electroosmosis and gas generated by electrolysis. It was ensured that efficient dehydration performance was obtained. This is because there is a proper gap between the warp and the weft to prevent sludge particle permeation, drainage, and exhaust gas function.
In addition, the conductive wire 13 involved in the current-carrying function has a large area exposed to the slurry passage side as seen in the plan view of FIG.

Further, during the dehydration operation, the press belt 6 on the anode side and the conveyor belt 2 on the cathode side were intentionally loosened to bring the belts into contact with each other, but no electrical short circuit occurred and sufficient safety was confirmed. . This is because the conductive wire 13 does not project to the surface of the net as described above, and when the belts contact each other, the insulating wire 14 of the net 15 bumps against each other to prevent the conductive wire 13 from contacting. Moreover, the warp and weft arrangements of the net 15 are not disturbed even after long-term operation under severe load conditions, and the drainage, exhaust gas function, and electrical short-circuit prevention function are excellent in addition to the function of energizing sludge as an electrode. It has been confirmed that it can be maintained.

〔The invention's effect〕

As described above, according to the present invention, a net is formed by weaving one of the conductive wire and the insulating wire as the warp thread and the other as the weft thread, and the conductive wire sticks out to the net surface at least on the side facing the slurry passage. Since the electrode is constructed by weaving it inside the insulated wire to prevent it, while ensuring a good electricity-carrying function to the sludge required for the electrode, as well as collecting, draining, and exhaust gas functions of sludge particles, the electrode is in operation. Even when the belts on the anode side and the cathode side, which also serve as the electrodes, directly contact each other, it is possible to reliably prevent the belt itself from causing an electrical short circuit between the electrodes. Moreover, unlike the conventional short-circuit prevention measure, it is not necessary to additionally provide another insulating member between the electrodes, and there is an advantage that the structure and maintenance of the electroosmotic dehydrator can be simplified.

[Brief description of drawings]

1 is a plan view of an electrode structure according to an embodiment of the present invention, FIG. 2 is a sectional view of FIG. 1, FIG. 3 is a configuration diagram of a belt press type electroosmotic dehydrator, and FIGS. 4 and 5 are respectively. The arrow XX in FIG. 3 showing the conventional measure for preventing short circuit between electrodes
FIG. In each figure, 1: hopper for supplying sludge, 2: conveyor belt also serving as cathode side electrode, 3: slurry passage, 6: press belt also serving as anode side electrode, 8: power supply, 9: sludge, 10: dehydration Cake, 13: Conductive wire, 1
4: Insulated wire, 15: Belt net.

Claims (2)

[Claims] 1. An electrode for an electroosmosis dehydrator, in which an anode-side electrode and a cathode-side electrode are opposed to each other with a slurry passage sandwiched therebetween, and the sludge supplied to the slurry passage is electroosmotically dehydrated while a voltage is applied between the electrodes. One of the conductive wire and the insulated wire is warp yarn,
An electro-osmotic type characterized in that it is formed as a net woven with the other side as a weft thread, and that the conductive wire is woven inside the insulating wire at least on the side facing the slurry passage so as not to project to the net surface. Dehydrator electrode. 2. The electrode according to claim 1, wherein the conductive wire is a metal wire having high corrosion resistance, the insulating wire is a synthetic fiber thread, and the linearly extended metal wire is a weft thread or an insulating wire. An electrode for an electro-osmotic dehydrator, which is a belt-like net woven with warp as a warp yarn.