JP2643511B2 - Electroosmotic dehydrator - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electroosmotic dewatering machine for continuously dewatering sludge, for example, for surplus sludge generated in a sewage treatment plant.

[Conventional technology]

As the electro-osmotic dehydrator mentioned above, for example,
The rotary drum type electroosmotic dehydrator described in 256112 has already been put to practical use.

Next, an outline of the rotary drum type electroosmotic dehydrator will be described with reference to FIG. In the drawing, reference numeral 1 denotes a rotary drum having an anode electrode plate 1a on its peripheral surface, and reference numeral 2 denotes an endless metal press which surrounds a part of the peripheral area of the rotary drum 1 and is stretched around guide wheels 3 of sprockets or pulleys. Belt, 4 is a filter cloth belt superimposed on the circumference of the press belt 2, 5 is a DC power source for applying a voltage between the electrodes using the rotating drum 1 as an anode and the press belt 2 as a cathode, and 5 a and 5 b are + Pole,-
A brush for power supply and current collection that is connected to the pole terminal and contacts the rotating shaft of the rotating drum 1 and the rotating shaft of the guide wheel 3 on which the press belt 2 is stretched. A sludge passage is defined between the belt and the belt 4.

In the above configuration, the press belt 2 is circulated in the direction of the arrow by a drive motor (not shown), and the object to be dewatered is passed through the sludge passage in a state where a DC voltage is applied between the rotary drum 1 and the press belt 2. When a certain sludge 7 is supplied, the sludge 7 is sandwiched between the rotary drum 1 and the press belt 2 and is conveyed while receiving a mechanical squeezing force, and at the same time, is subjected to an electroosmotic action by an electric field between the counter electrodes. . Due to this electroosmotic action, the water contained in the sludge 7 is positively charged and collected on the cathode side, from which the filter cloth belt 4, the press belt 3
And flows down to the drainage tray 6 and is discharged out of the system. On the other hand, the sludge 7 is changed into a dewatered cake having a low water content by dewatering, and is separated and collected from the press belt 2 at the outlet side of the sludge passage.

In the above example, the polarity of the rotary drum 1 (non-water collecting side) was positive and the polarity of the press belt 2 (water collecting side) was negative because the ζ-potential of the particles of the sludge 7 was negative. When the ζ-potential of the sludge particles is positive, conversely, the polarity of the rotary drum 1 is determined to be negative and the polarity of the press belt 2 is determined to be positive, and the voltage is applied.

The press belt 2 has a segment structure or a wire mesh structure. Here, as shown in FIGS. 6 and 7, the segment type press belt is an endless chain 9 in which a number of strip-shaped segments (made of stainless steel) 8 are used as electrode plates, and each segment 8 is laid on both left and right sides thereof. The chain 9 is stretched around the sprocket shown in FIG. Reference numeral 8a denotes a drainage permeation hole 8a formed in the plate surface of the segment 8.

[Problems to be solved by the invention]

By the way, in the above-mentioned conventional rotary drum type electroosmotic dehydrator, one pole of the power source 5 and the press belt 2 are electrically connected via a brush 5b as shown in FIG.
That is, the current collecting point for the press belt 2 is the rotating drum 1
It is located at a position deviated from the dehydration section opposite to.

For this reason, in the segment-type press belt shown in FIGS. 6 and 7, the current flowing into the segment 8 through the sludge 7 in the region of the dewatering section is collected on the brush 5b via the chain 9, the guide wheel 3 (sprocket). Will be charged. Thus, the chain 9 is a flexible connecting member in which a roller link and a pin link are pin-connected, and a non-conductive substance such as lubricating oil is attached to a sliding surface between the links.
For this reason, when the chain is viewed as a current path, the electrical connection between the links is incomplete, and the effective electrical resistance in the longitudinal direction is considerably large.

As described above, in the conventional current collecting method in which the press belt 2 itself is used as a current path and a current is caused to flow in the longitudinal direction to collect current, an effective power supply circuit between the power source and the electrode is used for the press belt 2 itself. The electric resistance causes a large power loss, and the voltage of the power supply 5 needs to be increased accordingly in order to flow the required current to the sludge 7 in the dewatering section. As a result, the power consumption increases and the running cost increases. Will be higher.
Further, in the case of the segment-type press belt, the chain 9 generates abnormal heat due to the supplied current, and in the case of the wire mesh press belt, the filter cloth belt 4 knitted with fibers such as nylon is damaged by the heat generated by the belt itself. I do.

The present invention has been made in view of the above points,
It is an object of the present invention to provide an electroosmotic dehydrator capable of reducing power consumption by improving a current collecting method for a press belt and preventing abnormal heating of the press belt.

[Means for solving the problem]

In order to solve the above problems, in the electroosmotic dehydrator of the present invention, as a first solution, the press belt and the power supply are connected in the entire dehydration section where the anode and cathode electrodes face each other. A current collecting member of a sliding contact type, the current collecting member includes a plurality of elastic current collecting shoes and one current collecting rail, and the current collecting rail is electrically connected to the power supply. The electric collecting shoe is connected and fixed to each of the segments constituting the segment type press belt, and is in contact with the collecting rail.

Further, as a second solution, it is assumed that adjacent segments are electrically connected to each other via a conductive wire with respect to the segments constituting the segment type press belt.

[Action]

According to the first solution described above, in the dehydration section in which the anode and the cathode are opposed to each other, a current collecting member including a current collecting shoe and a current collecting bar in which the current is more elastic than the press belt in the entire area is provided. The power is then collected on the power supply side. Therefore, there is almost no increase in the circuit resistance between the press belt and the power supply, and an increase in power loss due to the electric resistance of the current path along the longitudinal direction of the press belt itself, and efficient operation by suppressing heat generation of the press belt itself. it can. In addition, as a method similar to a structure imagined from a structure of a rotating electric machine including a conventional carbon brush, a method of connecting and fixing the plurality of current collecting shoes to an electric current collecting rail and abutting on the press belt can be considered. In this method, the number of collecting shoes is small and the structure is simple, but in this method, when the segment type press belt passes through the portion of the collecting shoe having a high potential, There is a problem that a spark is generated because the high potential and the no potential are alternately repeated in the segment due to the existence of the gap.

On the other hand, according to the above-described method, the current collecting shoe electrically connected to the current collecting rail and the segment have the same electric potential, so that a spark is generated in the press belt in the area of the current collecting rail. Problem is solved.

Further, according to the second solution, the segments of the segment type press belt are electrically connected to each other via the conductive line having a small electric resistance without passing through the chain. Therefore, even if the current collecting point of the press belt is set at a position separated from the dewatering section, it is possible to operate efficiently by suppressing excess power loss and heat generation of the press belt.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings of the embodiments described below, the same members corresponding to FIGS. 5 to 7 are denoted by the same reference numerals.

Embodiment 1: FIGS. 1 and 2 show an embodiment of the present invention corresponding to the above-mentioned first solution means for a segment type press belt. In this embodiment, for each of the segments 8 constituting the segment-type press belt 2, the left and right ends thereof are aligned in the longitudinal direction, and a current collecting shoe 12 formed by bending a metal piece such as stainless steel into a C-shape. Is a bolt
Secured by 13. On the other hand, an arc-shaped current collecting rail 14 slidably in contact with the tip of the current collecting shoe 12 is laid on the fixed side facing the row of the current collecting shoes 12. The current collecting rail 14 is, for example, a stainless steel bar (current collecting bar).
The rotary drum 1 and the press belt 2 are laid over the entire area of the dewatering section facing each other across the sludge passage, and one end thereof is connected to one pole terminal of the DC power supply 5 by wiring.

With such a configuration, the current flowing through each press belt segment 8 of the segment located in the dewatering section during operation is:
The current is individually collected on the current collecting rail 14 through the current collecting shoe 12, and flows from this to the negative electrode of the power supply 5. Therefore, by configuring the current collecting shoe 12 and the current collecting rail 14 in advance so as to contact each other with a sufficiently high contact pressure and suppressing the electrical contact resistance at this portion to a small value, the power in the current collecting path is reduced. Losses can be minimized. In addition, the current does not shunt the chain connected to the segment 8 (see FIGS. 5 and 6), and there is no possibility that the chain itself generates resistance heat.

Embodiment 2 FIGS. 3 and 4 show an embodiment of the present invention corresponding to the second solving means.

That is, in the segment-type press belt 2, the adjacent segments are electrically connected to each other by the conductive wire 18 over the entire peripheral area. The conductive wire 18 is, for example, a band-shaped braided copper wire having a large current carrying capacity woven with a tin-plated element wire so as to have flexibility, and is fastened between the segments 8 with bolts 19.

With this configuration, at the time of operation, the current flowing through the segment 8 located in the dewatering section is guided along the longitudinal direction of the press belt, successively through the low-resistance conductive wires 18 to the current collecting brush 5b, and the effective electrical resistance is reduced. The large chain 9 is not energized. Therefore, similarly to the above-described embodiments, an unnecessary increase in power loss can be suppressed, and there is no possibility of abnormal heat generation due to energization of the chain 9 itself.

〔The invention's effect〕

Since the electroosmotic dehydrator of the present invention is configured as described above, the following effects can be obtained.

That is, a sliding contact type current collecting member for connecting between the press belt and a power source is provided throughout the dehydration section where the anode and cathode electrodes face each other, and the current collecting member has a plurality of elastic members. And a current collecting rail, and the current collecting rail is electrically connected to an electric power source, and the current collecting shoe is connected and fixed to each of the segments constituting the segment type press belt. Shall be in contact with the rail,
Alternatively, the segments constituting the segment type press belt are electrically connected to each other through conductive wires between the adjacent segments, and (1) the electric resistance in the current collecting circuit between the press belt and the power source is reduced. The power consumption required for electroosmotic dehydration can be reduced by keeping the value low. Further, according to the method of the present invention, since the current collecting shoes and the segments electrically connected to the current collecting rail have the same potential, a plurality of current collecting shoes are connected and fixed to the current collecting rail, and the press belt is fixed. There is no problem that sparks occur as in the method of contacting with the vehicle, and safety can be ensured and the service life can be extended.

(2) It is possible to suppress abnormal heat generation due to energization of the press belt itself or the chain connected to the segment type press belt, and to avoid damage due to heating of the filter cloth belt superimposed on the press belt.

[Brief description of the drawings]

1 and 3 are diagrams showing the main parts of a different embodiment of the present invention, FIG. 2 is a partially enlarged sectional view of FIG. 1, and FIG.
FIG. 5 is a partially enlarged plan view of FIG. 5, FIG. 5 is a schematic diagram showing a general structure of a conventional rotary drum type electroosmotic dehydrator to which the present invention is applied, and FIG. 6 and FIG. FIG. 3 is a partial front view and a plan view thereof.
In the figure, 1: rotating drum, 2: press belt, 4: filter cloth belt, 5: DC power supply, 7: sludge, 8: segment, 12: current collecting shoe, 14: current collecting rail, 18: conductive wire.

Claims (2)

(57) [Claims] 1. A direct current voltage is applied between an anode and a cathode facing each other across a sludge passage, and water contained in the sludge supplied to the sludge passage is collected on one of the electrodes by an electroosmosis action. An endless segment type press belt in which one of the anode and cathode electrodes moves around, and the press is applied to the entire area of the dehydration section where the anode and cathode electrodes face each other. A sliding contact type current collecting member for connecting between the belt and the power supply, wherein the current collecting member comprises a plurality of elastic current collecting shoes and one current collecting rail; Is electrically connected to the power source, and the current collecting shoe is connected and fixed to each of the segments constituting the segment type press belt and abuts on the current collecting rail. 2. A direct current voltage is applied between the anode and cathode electrodes facing each other across the sludge passage, and the water contained in the sludge supplied to the sludge passage is collected on one of the electrodes by electroosmosis, and the system outside the system. Of an endless segment-type press belt in which one of the anode and cathode electrodes moves in a circle, between the segment forming the segment-type press belt and the adjacent segment Are electrically connected to each other through a conductive wire.