JP2004041897A - Discharge electrode for electric dust precipitator and method of manufacturing the discharge electrode - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an electric dust precipitator which can be continuously operated for a long period of time while the electrode is not easily broken even when a spark discharge occurs during operating the electric dust precipitator. <P>SOLUTION: The discharge electrode main body 16 in a square plate form is formed by using a metal mesh. The discharge electrode 20 has a needle-like projection 17a in the mesh by arranging a wire material 17 of a specified length to protrude in the position between intersections 18 of the wires 17 of the metal mesh in the direction along the mesh plane to form the needle-like projection 17a. The discharge electrode 20 is assembled in an electric dust precipitator and voltage is applied between the electrode and a counter electrode to generate a corona discharge by using the top end of each needle-like projection 17a as the discharge point. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a discharge electrode used in an electric precipitator installed in the middle of an exhaust gas duct to collect floating dust in the exhaust gas and clean the exhaust gas, and a method for manufacturing the discharge electrode.
[0002]
[Prior art]
For example, in a road tunnel, an exhaust duct leading to an exhaust tower on the ground is provided on the tunnel wall in order to discharge exhaust gas and the like discharged from a vehicle traveling in the tunnel to the ground, and in the middle of the exhaust duct. An electric precipitator is installed, and the exhaust gas in the tunnel sucked by the exhaust fan is cleaned by passing through the electric precipitator and then exhausted to the atmosphere through an exhaust tower.
[0003]
There are a two-stage type and a single-stage type of electric dust collector used in the tunnel and the like.
[0004]
As shown schematically in FIG. 7, the two-stage type electrostatic precipitator has a gas passage 3 in a housing 4 in which an inlet 1 side and an outlet 2 side are opened and the inside is a gas passage 3. 5, a charging unit 6 is provided on the upstream side in the flow direction, and a dust collecting unit 7 is provided on the downstream side. A plurality (two in the figure) of the charging units 6 are arranged, for example, extending in the vertical direction so as to cross the flow direction of the gas 5, and are arranged in front and behind at a required interval along the flow direction of the gas 5. A plurality of discharge electrodes 9 each having a set of the tungsten discharge wires 8 are arranged in parallel in a horizontal direction at regular intervals (three rows in the figure), and a plurality of discharge electrodes 9 are arranged at positions sandwiching the discharge electrodes 9 in each row. A pair of stainless steel plate-like counter electrodes 10 are arranged in parallel along the flow direction of the gas 5 and at a constant interval in the left-right direction, and each discharge electrode 9 is connected to a power supply 11 for discharge. Each counter electrode 10 is grounded, and a DC voltage is applied between the discharge electrode 9 and the counter electrode 10 by the discharge power supply 11 to generate a corona discharge from the discharge electrode 9 to the counter electrode 10, Between each discharge electrode 9 and each counter electrode 10 The particulate matter over to gas 5 are as brought charged. In addition, the dust collecting section 7 arranges the first flat dust collecting electrodes 12 and the second dust collecting electrodes 13 made of stainless steel in parallel to the flow direction of the gas 5 and alternately in the left-right direction at a constant interval. The first dust collecting electrode 12 is connected to a power source 14 for forming an electric field, the second dust collecting electrode 13 is grounded, and the first dust collecting electrode 12 and the second dust collecting electrode are arranged. 13, a DC voltage is applied by a power supply 14 to form a DC electric field having a high potential from the second dust collecting electrode 13 toward the first dust collecting electrode 12, and the charging unit 6 charges the DC electric field. The particulate matter thus collected is collected by the first dust collecting electrode 12 and the second dust collecting electrode 13 by Coulomb force. As the discharge electrode 9, a single wire of the discharge wire 8 or a combination or structure of a single wire is adopted.
[0005]
On the other hand, the one-stage electric precipitator has only a dust collecting portion, and has a basic configuration substantially the same as the charging portion 6 of the two-stage electric precipitator. The number of discharge wires 8 is increased by increasing the length in the flow direction. That is, as shown in FIG. 8, an example of a single-stage electric precipitator has a plurality of (three in FIG. 3) dangsten discharge wires 8 as one set in a gas flow path 3 in a housing 4. The electrodes 9 are arranged in a plurality of rows (four rows in the figure) at regular intervals in the left-right direction, and are formed at positions sandwiching the discharge electrodes 9 so as to be wide in the flow direction of the gas 5. The plate-like counter electrodes 10 are arranged side by side in parallel at a constant interval in the left-right direction, each discharge electrode 9 is connected to a power source 15 which is a power source for discharging and a power source for forming an electric field, and each counter electrode 10 is grounded. By applying a DC voltage between the discharge electrode 9 and each counter electrode 10 by the power supply 15, a corona discharge is generated from the discharge electrode 9 to the counter electrode 10, and the discharge electrode 9 and the counter electrode 10 are connected to each other. To create an electric field between , It is constituted such that it is trapped by the dust collecting particulate matter in the gas 5 was charged in the opposing electrode 10.
[0006]
[Problems to be solved by the invention]
However, since the discharge electrode 9 used in the conventional two-stage electric precipitator and the one-stage electric precipitator is a single discharge wire or a combination of single discharge wires made of tungsten 8, the discharge electrode 9 is frequently used during operation. There is a problem that the discharge wire 8 often breaks (disconnects) due to the generated spark discharge phenomenon. That is, in the electrostatic precipitator, when the voltage between the discharge electrode 9 and the counter electrode 10 is a high voltage immediately before the discharge generated between the discharge electrode 9 and the counter electrode 10 shifts from corona discharge to spark discharge, It is known that high performance is exhibited, and when operating at such a high voltage, spark discharge occurs due to the temperature of the gas 5, the density of fine particles, the state of fouling of the discharge electrode 9, and the like. When the discharge wire 8 is generated, the discharge wire 8 is melted by heat generated in a larger amount than the corona discharge due to the spark discharge, or the discharge wire 8 is easily oxidized and degraded, and is broken. If the discharge wire 8 breaks and comes into contact with the counter electrode 10, an operation failure occurs. If the operation is stopped and the discharge wire 8 is not replaced, the subsequent operation cannot be performed. Has a problem that the operation is frequently stopped due to replacement because it is easily broken. Therefore, it has been unsuitable for a single-stage electric precipitator that uses a large number of tungsten discharge wires side by side.
[0007]
Therefore, the present invention provides a discharge electrode for an electrostatic precipitator and a method for manufacturing the discharge electrode, which can perform stable continuous operation for a long time without easily breaking even if a spark discharge occurs during operation. What you are trying to do.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention attaches a wire in a direction along a mesh surface to a mesh-forming wire of a flat discharge electrode body made of a metal mesh structure, and a large number of wires are provided in the mesh. A discharge electrode for an electrostatic precipitator having a configuration formed with needle-like projections.
[0009]
In the case of incorporating and using in an electric precipitator, even if the operation shifts from corona discharge to spark discharge by operating at a high voltage, since the tip of the needle-shaped projection is a discharge point, breakage of the discharge electrode body is avoided, Long-term continuous operation becomes possible.
[0010]
Further, by making each needle-like projection formed in the mesh bend appropriately to the front side and the back side or the front side or the back side of the discharge electrode main body, the discharge electrode main body can be formed on both the front and back sides. The uniformity of corona discharge can be improved.
[0011]
On the other hand, a flat wire mesh is used as a discharge electrode body, and a required intersection portion is cut out of each intersection formed by each wire of the wire mesh forming the discharge electrode body so that a needle-like projection is formed in the mesh. By using the method for manufacturing a discharge electrode for an electrostatic precipitator described above, the discharge electrode can be easily and efficiently manufactured.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0013]
FIG. 1 shows an embodiment of the present invention, in which a large number of wires 17 are crossed obliquely and combined to form a required mesh. A discharge electrode body 16 having a size is required, and both sides of a central portion between the intersections 18 of the wires 17 constituting the discharge electrode body 16 are required in a direction perpendicular to the direction along the mesh surface (the flat plate direction). The length of the wire 17 is protruded to form a discharge needle-like projection 17a, and a plurality of (four in the figure) needle-like projections 17a are formed in each mesh. A discharge electrode 20 for an electrostatic precipitator having a configuration in which discharge is performed and a peripheral portion of the discharge electrode body 16 is held by a reinforcing frame 19.
[0014]
Next, a specific manufacturing procedure of the discharge electrode 20 for an electric dust collector of the present invention having the above-described configuration will be described.
[0015]
FIGS. 2 (a) and 2 (b) show an example of a method for manufacturing a discharge electrode for an electrostatic precipitator of the present invention, in which a large number of conductive metal wires 17 are combined so as to be orthogonal to each other, and intersections 18 of the wires 17 are integrated by welding. This shows a case in which a wire mesh of a rectangular flat plate having a required size is used as the discharge electrode main body 16, and the vertical and horizontal directions of each mesh of the discharge electrode main body 16 configured as shown in FIG. As shown in FIG. 2B, a portion of each intersection 18 lined up in the direction is cut evenly or unequally by a punch or a partial cutting machine to form a large number of needle-like projections 17a by the wire 17, and the needle-like projections 17a are formed. Is formed in a mesh over the entire surface of the discharge electrode main body 16. Thereafter, as shown in FIG. 1, the frame 19 is attached to the outer peripheral edge of the wire mesh.
[0016]
In addition, as the wire mesh that becomes the discharge electrode body 16, the case where the above-mentioned many wires 17 are combined so as to be knitted and the respective intersections 18 are welded and integrally manufactured is exemplified, but the expanded metal method, the notch wire method, or the like is used. Even when a mesh-shaped one is manufactured and used as the discharge electrode main body 16, the needle-shaped projection 17a is formed as shown in FIGS. A discharge electrode can be manufactured. In addition to the method of forming the needle-like projections 17a by cutting off the mesh intersections 18 of the wire mesh, the discharge electrode 20 for an electrostatic precipitator of the present invention may be provided on both sides of the center of the wire 17 located between the intersections of the wire mesh. Alternatively, a short wire may be attached by welding or the like so as to protrude in a direction along the net surface to form the needle-like projection 17a. In this case, if the size of each mesh is increased in advance, a discharge electrode for an electrostatic precipitator having the same size as that shown in FIGS. 1 and 2 (b) can be obtained.
[0017]
The discharge electrode 20 for an electric precipitator of the present invention can be used in place of the discharge electrode 9 of the two-stage electric precipitator shown in FIG. 7 or the one-stage electric precipitator shown in FIG. In this case, as shown in FIGS. 3 and 4, the discharge electrode 20 of the present invention is arranged in parallel at an intermediate position of the plate-like counter electrode 10 so that the discharge electrode 20 and the counter electrode 10 are interposed. When a voltage is applied, corona discharge does not occur from the continuous wire material 17, but corona discharge occurs from the discharge point at the tip of the needle-like projection 17 a. Therefore, even if the operation is changed from corona discharge to spark discharge by operating at a high voltage, melting and oxidative deterioration can be stopped only at the tip of the needle-like projection 17a, and the discharge electrode body 16 itself, which is a mesh-like structure, is Dissolution and oxidative deterioration do not occur easily. Accordingly, the electrode body 16 is not easily broken, and the electric precipitator can be stably operated continuously for a long time.
[0018]
Next, FIG. 5 shows another embodiment of the present invention. In the same configuration as the discharge electrode 20 shown in FIG. 1, each of the needle-like projections 17a arranged in the vertical direction and the horizontal direction of the discharge electrode main body 16 is shown. Are alternately bent or curved alternately to the front side and the back side to deflect.
[0019]
As shown in FIG. 5, if the tip of each needle-like projection 17a is alternately bent toward the front side and the back side of the discharge electrode body 16, the directivity of corona discharge generated from the tip of the needle-like projection 17a is determined. The uniformity and stability of corona discharge on both the front and back surfaces of the discharge electrode body 16 can be improved.
[0020]
Although the embodiment of FIG. 5 shows a case where the tips of the four needle-like projections 17a formed in one mesh are bent to the front side and the back side of the discharge electrode main body 16, all the cases are the same. May be bent in the direction to alternately become the front side and the back side for each of the adjacent meshes, and the bend may be entirely bent from the base of each needle-like projection 17a. In addition, the number and position of the needle-like projections 17a serving as discharge points can be arbitrarily selected, whereby an optimal electric precipitator can be manufactured as required. Further, in the embodiment, a wire rod is used. Although the case where the discharge electrode main body 16 is constituted by a mesh-like structure having a mesh structure in which the wires 17 are crossed obliquely is shown, as shown in FIG. 6 corresponding to FIG. 1, the wires 17 are combined vertically and horizontally. May be Further, in the embodiment, the case where the discharge electrode main body 16 is held by the frame 19 has been described. However, the frame 19 is not indispensable, and the frame 19 does not deviate from the gist of the present invention. It goes without saying that various changes can be made in.
[0021]
【The invention's effect】
As described above, according to the present invention, the following excellent effects are exhibited.
(1) A structure in which a wire is attached in a direction along a mesh surface to a mesh-forming wire of a flat discharge electrode body made of a metal mesh structure to form a large number of needle-like projections in the mesh. Since it is a discharge electrode for an electrostatic precipitator having a high voltage, even if the electric precipitator is operated at a high voltage, even if the discharge shifts from corona discharge to spark discharge, it is possible to avoid breakage of the discharge electrode and maintain a stable state for a long time. Continuous operation can be performed. Therefore, it can be effectively adopted for a single-stage electric precipitator.
(2) Each of the acicular projections formed in the mesh is appropriately bent to the front side and the back side or the front side or the back side of the discharge electrode main body, so that the corona discharge from the acicular projections is formed. Since the directivity is determined, uniformity and stability of corona discharge on both the front and back surfaces of the discharge electrode main body can be improved.
(3) A flat wire mesh is used as a discharge electrode body, and a required intersection portion is cut out of each intersection formed by wires of the wire mesh forming the discharge electrode body to form needle-like projections in the mesh. By using the method for manufacturing a discharge electrode for an electrostatic precipitator described above, the discharge electrode can be efficiently and easily manufactured without a lot of trouble.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an embodiment of a discharge electrode for an electric dust collector according to the present invention.
FIG. 2 shows an example of a method of manufacturing a discharge electrode for an electrostatic precipitator according to the present invention, wherein (a) is a view of the discharge electrode body, and (b) is a drawing of a large number of needle-like projections from the discharge electrode body of (a). It is a schematic diagram showing the state where it was formed.
FIG. 3 is a schematic plan view showing a state where the discharge electrode for an electric precipitator of the present invention is employed in a two-stage electric precipitator.
FIG. 4 is a schematic plan view showing a state where the discharge electrode for an electric precipitator of the present invention is employed in a one-stage electric precipitator.
FIG. 5 is a perspective view showing another embodiment of the present invention.
FIG. 6 is a schematic diagram showing still another embodiment of the present invention.
FIG. 7 is a schematic plan view showing an example of a conventional two-stage electric dust collector.
FIG. 8 is a schematic plan view showing an example of a conventional one-stage electric precipitator.
[Explanation of symbols]
16 Electrode body 17 Wire 17a Needle-like projection 18 Intersection

Claims (3)

A structure in which a wire material is attached in a direction along a mesh surface to a wire material for forming a mesh of a flat discharge electrode body made of a metal mesh structure to form a large number of needle-like protrusions in the mesh. A discharge electrode for an electrostatic precipitator. 2. The discharge electrode for an electrostatic precipitator according to claim 1, wherein each needle-like projection formed in the mesh is appropriately bent to the front side and the back side or the front side or the back side of the discharge electrode main body. A flat wire mesh is used as a discharge electrode main body, and a required intersection portion is cut out of each intersection formed by each wire of the wire mesh forming the discharge electrode main body so that a needle-like projection is formed in the mesh. A method for manufacturing a discharge electrode for an electrostatic precipitator, comprising:

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