JP2004181381A - Discharge electrode of electrostatic precipitator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the operation stop of an entire apparatus by a short circuit even when the end part of a discharge wire is broken. <P>SOLUTION: A discharge electrode 10 is constituted of a conductive discharge frame 12 and a large number of conductive discharge wires 14. In the discharge frame 12, vertical pipes 12A and horizontal pipes 12B are arranged in the shape of a lattice. In each lattice frame, the discharge wires 14, with both end parts fixed to the horizontal pipes 12B, are stretched vertically to the discharge frame 12. To both end parts of each discharge wire 14, protective caps 16 wrapping the end parts are fitted. Even when the end part of the discharge wire is broken, the action of the broken discharge wire is restrained by the protective cap 16. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a discharge electrode of an electrostatic precipitator, and more particularly to a discharge electrode of a large-sized dry electric precipitator for treating exhaust gas from a boiler or an incinerator.
[0002]
[Prior art]
In this type of dry electrostatic precipitator, a discharge electrode as shown in FIG. 8 is generally employed. The discharge electrode 1 is mainly composed of a conductive discharge frame 2 and a large number of conductive discharge wires 3. The discharge frame 2 is formed by welding a vertical pipe 2A and a horizontal pipe 2B in a grid shape by welding. In the illustrated discharge frame 2, a total of 12 grid frames of 3 × 4 are formed. Each grid frame has three discharge wires 3 fixed at its both ends to the horizontal pipe 2B by welding or the like, and extends vertically to the discharge frame 2. Accordingly, the illustrated discharge electrode 1 has a total of 36 discharge lines 3 of 12 × 3. The discharge electrode 1 is suspended via a support 4, and a high voltage is applied by connecting to a power supply (not shown). As the discharge wire 3, a wire using a round wire or a square wire, a strip wire, or the like is employed.
[0003]
As shown in FIG. 9A, the discharge electrodes 1 are alternately arranged with the collection electrode plates 5 in the casing of the electric precipitator. When a high voltage is applied to the discharge electrode 1, corona discharge is generated between the discharge electrode 1 and the dust collecting electrode plate 5. The dust in the gas passing through the casing is charged by the corona discharge, and is attracted to and adheres to the dust collecting electrode plate 5. Dust adhering and accumulating on the dust collecting electrode plate 5 is removed from the dust collecting electrode plate 5 by operating a hammering means (not shown) provided on the dust collecting electrode plate 5 at predetermined time intervals. The discharge electrode 1 is also provided with a hammering rod 6 for stably maintaining the corona discharge. The hammering rod 6 is hammered separately from the dust collecting electrode plate 5 so that a discharge wire is provided. Remove dust adhering to 3.
In a large-sized dry-type electrostatic precipitator, several tens to several hundreds of discharge electrodes 1 as described above are mounted per unit. Therefore, when converted into the number of discharge lines, several thousand discharge lines 3 are used per unit.
[0004]
By the way, in this type of electrostatic precipitator, when the discharge electrode 1 is hammered, a strong impact stress due to hammering acts on the discharge wire 3 each time. If such an impact stress is frequently applied repeatedly for a long period of operation, the discharge wire 3 may cause fatigue fracture and break. Then, the broken discharge wire may be deformed by its own weight and come into contact with the adjacent dust collecting electrode plate 5 as shown in FIG. Even if only one of the thousands of discharge wires 3 per unit breaks, when it contacts the dust collecting electrode plate 5 as described above, a short-circuit causes a charging abnormality and the entire unit stops operating. Become. (For example, refer to Patent Document 1.)
[0005]
It is said that such a breakage of the discharge wire not only has an impact stress due to hammering, but also has a large corrosive environment due to the temperature and properties of the gas to be treated and an electrical effect due to energization. Making it difficult. Therefore, it is practically difficult to completely eliminate the breakage of the discharge wire.
[0006]
[Patent Document 1]
JP 10-113575 A
[Problems to be solved by the invention]
The present invention has been made under such a background, and an object of the present invention is to solve the above-mentioned problems of the prior art, and to stop the operation of the entire apparatus even when the discharge wire is broken. An object of the present invention is to provide a discharge electrode of an electric precipitator which can be avoided with a high probability.
[0008]
[Means for Solving the Problems]
In order to solve the above-described problem, the discharge electrode of the electrostatic precipitator according to the present invention fixes the both ends of the discharge wire to the discharge frame, so that the discharge wire passes over the discharge frame. In the discharge electrode of the electrostatic precipitator described above, a protective cap for covering the end of the discharge wire is attached to an end of the discharge wire.
[0009]
Further, in the discharge electrode of the electrostatic precipitator according to the present invention, in the above configuration, the discharge wire is a discharge wire having a plurality of protrusions, and the protective cap surrounds a base end of at least one protrusion. In addition, the tip of the projection is exposed to the outside.
[0010]
Further, the discharge electrode of the electrostatic precipitator according to the present invention, in the above configuration, is characterized in that the protective cap has a split structure and is attached so as to sandwich the end of the discharge wire from both sides. .
Further, the discharge electrode of the electrostatic precipitator according to the present invention is an electric precipitator in which both ends of the discharge wire are fixed to the discharge frame so that the discharge wire is passed vertically to the discharge frame. In the discharge electrode of the apparatus, a restraining means is provided at an upper end position of the discharge wire to prevent the discharge wire from falling down when the upper end portion of the discharge wire is broken.
[0011]
[Action]
In the present invention, the above-described breakage of the discharge wire is likely to occur at the end near the fixed portion with the discharge frame, and hardly occurs at the middle of the discharge wire, and when the upper end of the discharge wire breaks, a short circuit occurs. It was made focusing on the fact that it could easily lead to an accident.
That is, even if the end of the discharge wire is broken by attaching the protective cap wrapping the end of the discharge wire, the movement of the broken discharge wire is restrained due to the presence of the protective cap, so that the adjacent collection can be prevented. Contact with the dust plate can be prevented. For this reason, it is possible to prevent the occurrence of a situation in which the entire apparatus is stopped due to a short circuit with a high probability.
[0012]
In addition, since the restraining means for preventing the discharge wire from falling down when the upper end portion of the discharge wire breaks is provided at the upper end position of the discharge wire, the broken discharge wire falls down by its own weight and the adjacent dust collecting plate Can be prevented from coming into contact with.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a partial side view showing a first embodiment of a discharge electrode of an electric precipitator according to the present invention. The discharge electrode 10 mainly includes a conductive discharge frame 12 and a number of conductive discharge wires 14. The discharge frame 12 is formed by welding a vertical pipe 12A and a horizontal pipe 12B made of steel in a grid shape by welding, and each grid frame has a plurality of (seven in the illustrated case) discharge wires 14 at both ends. The portion is fixed to the horizontal pipe 12B by welding, and extends vertically to the discharge frame 12. Protective caps 16 are attached to both ends of each of the discharge wires 14, 14,.
[0014]
2A and 2B show both end portions of the discharge wire 14, in which (1) is a front sectional view and (2) is a side sectional view. The lower end of the upper discharge line 14 is fixed above the horizontal pipe 12B, and the upper end of the lower discharge line 14 is fixed below. The main part of the discharge wire 14 is a strip, and a plurality of projections 18 and 19 are formed at regular intervals in the vertical direction of the strip and the adjacent projections 18 and 19 are formed in alternate directions. I have. That is, in FIG. 2A, the tip of the projection 18 formed on the left side faces a left-side dust collecting electrode plate (not shown), and the tip of the projection 19 formed on the right side has a right-side dust collecting electrode (not shown). It is suitable for boards. Therefore, when a high voltage is applied to the discharge wire 14, a corona discharge current flows from the tips of the projections 18 and 19, and a uniform electric field having a predetermined gradient is formed.
[0015]
A pin rod 20 is fixed to the lower end of the strip of the upper discharge wire 14 by welding, and the lower end of the pin rod 20 is fixed to the upper surface of the horizontal pipe 12B by welding. A pin rod 22 is fixed to the upper end side of the lower discharge wire 14 by welding, and the upper end of the pin rod 22 is inserted into a hole formed on the lower surface of the horizontal pipe 12B and fixed by welding. By such a welding and fixing structure of the horizontal pipe 12B and the discharge wire 14, a high voltage from a high-voltage power supply is applied to each discharge line 14 via the vertical pipe 12A and the horizontal pipe 12B of the discharge frame 12.
[0016]
At both ends of the discharge wire 14, protective caps 16 wrapping each end are attached. In FIG. 2, only the protective cap 16 attached to the upper end of the lower discharge wire 14 is shown, and the protective cap 16 attached to the lower end of the upper discharge wire 14 is omitted. The protective cap 16 is made of a non-conductive synthetic resin, and is attached so as to cover the entire range of the end of the discharge wire where breakage is expected. In the state shown in FIG. 2, the portion of the pin rod 22 sandwiched between the lower surface of the horizontal pipe 12B and the upper end of the lower discharge wire 14 is most likely to break. Therefore, the protective cap 16 is attached with the upper end of the protective cap 16 as close as possible to the lower surface of the horizontal pipe 12B so as to securely cover the most fragile area.
[0017]
As shown in FIG. 3, the protective cap 16 has a two-part structure including caps 16A and 16B. The cap 16 </ b> A includes a semi-cylindrical pin rod housing 24 for enclosing the pin rod 22, and flanges 26 provided on the left and right sides of the pin rod housing 24. The flange 26 has a total of six hook holes 28. Is provided. The cap 16 </ b> B includes a band plate accommodating portion 30 for enclosing the band portion of the discharge wire 14, and flanges 32 provided on left and right sides of the band plate accommodating portion 30. The flange 32 has a position corresponding to the hook hole 28. Are provided with a total of six hooks 34. Further, the cap 16B is provided with through portions 36 and 38 of the projection 18 and the projection 19 of the discharge wire 14.
[0018]
The cap 16A and the cap 16B are brought close to each other so as to sandwich the upper end of the discharge wire 14 from both sides. The hook 34 provided on the flange 32 is inserted into the hook hole 28 of the flange 26 from the state shown in FIG. As a result, by the elastic action of the hook 34, the connection between the flange 26 and the flange 32 can be realized with one touch as shown in FIG. As a result, the protective cap 16 encloses the pin bar 22 at the upper end of the discharge wire 14, the upper end of the strip, and the base end of the two projections 18 and 19 provided at the upper end of the strip. The projection 18 or 19 penetrates the penetrating portion 36 or 38, respectively, as shown in FIG. 2A, and its tip is exposed to the outside of the protective cap 16. Therefore, even if the protective cap 16 is attached, the discharge action of the two projections 18 and 19 at this position is not hindered. Further, the projections 18 and 19 themselves serve to prevent the protective cap 16 from falling downward.
[0019]
In the above configuration, it is assumed that the upper end of the discharge wire 14 wrapped by the protective cap 16 has been broken for some reason. Typical positions of the expected fractures are shown as X and Y in FIG. The fracture X is a fracture of the strip, and the fracture Y is a fracture of the pin bar 22. Actually, the fracture Y is large and the possibility of the fracture X is extremely small. Even if these breaks X and Y occur, the upper break end fixed to the horizontal pipe 12B restrains the movement of the lower break end holding the protective cap 16. For this reason, it is possible to prevent the discharge wire 14 having the fractured top surface from falling down by its own weight, and to avoid a contact phenomenon with the dust collecting electrode plate as shown in FIG. 9 (2). Therefore, the worst case of stopping the operation of the entire apparatus due to a short circuit can be avoided. The break X and Y impair the conductivity between the upper horizontal pipe 12B and the discharge wire 14 whose upper end has a broken surface, but the lower end of the broken discharge wire 14 is electrically connected to the lower horizontal pipe (not shown). Therefore, the broken discharge wire 14 still exerts a normal discharge function.
[0020]
As shown in FIG. 1, the protective cap 16 is similarly attached to the lower end of the discharge wire 14. However, when the lower end of the discharge wire 14 breaks, most of the discharge wire 14 is suspended by its own weight from above, so the possibility that the lower end of the broken discharge wire comes into contact with the dust collecting electrode plate is unlikely. Relatively low. Therefore, in some cases, the attachment of the protective cap 16 on the lower end side can be omitted.
[0021]
Further, as described above, there is almost no breakage in the middle of the discharge wire 14. Therefore, in the present invention, even if only the upper end portion of the discharge wire 14 is wrapped with the protective cap 16, a situation in which the entire apparatus is stopped due to the breakage of the discharge wire can be avoided with a considerably high probability.
[0022]
In the first embodiment, the protective cap 16 has a two-part structure, and can be attached so that the upper end of the discharge wire 14 is sandwiched from both sides. The protective cap 16 can be easily attached to the discharge electrode of the device. Further, the protective cap 16 can be easily removed from the discharge electrode as needed.
[0023]
In the first embodiment, a protective cap 16 made of a non-conductive synthetic resin is used. Therefore, even if the broken discharge wire 14 is bent while holding the protective cap 16 at the end and comes into contact with the dust collecting electrode plate, a non-conductive protection is provided between the end of the discharge wire and the dust collecting electrode plate. The layer of the cap 16 will be interposed. Therefore, since the protective cap 16 functions as an insulating layer, adverse effects due to the short circuit phenomenon can be minimized. However, the protective cap 16 according to the present invention is not limited to the above-described non-conductive synthetic resin. In a high-temperature environment, a conductive metal may be used in consideration of heat resistance.
[0024]
It is preferable that the protective cap 16 is formed of a transparent material and that the dust is prevented from entering into the inside by using packing. By doing so, it is convenient that the state of breakage of the internal discharge wire can be visually determined only by wiping the outer surface of the protective cap 16 during maintenance and inspection.
[0025]
FIG. 5 is a conceptual diagram showing a second embodiment of the present invention. A discharge wire 42 is fixed to the horizontal pipe 12B via an L-shaped stopper 40 by bolt and nut means. A protective cap 44 indicated by a two-dot chain line is attached so as to surround the upper end of the discharge wire 42. The preferred shape of the protective cap 44 is selected according to the size and shape of the discharge wire 42 and the stopper 40.
[0026]
FIG. 6 is a perspective view showing a third embodiment of the present invention. Linear discharge wires 50 and 52 are fixed to the horizontal pipe 12B in the vertical direction, respectively. A pair of bands 54A and 54B sandwiching the horizontal pipe 12B and the discharge wires 50 and 52 from both sides are prepared. The bands 54A and 54B have four mating surfaces 56, and these mating surfaces 56 are tightened by fastening means such as bolts and nuts. As a result, the lower ends of the horizontal pipe 12B and the discharge wire 50 and the upper end of the discharge wire 52 are commonly wrapped by the bands 54A and 54B. With the above configuration, the combination of the pair of bands 54A and 54B functions as a protective cap when the lower end of the discharge wire 50 or the upper end of the discharge wire 52 is broken. According to the third embodiment, protection against breakage of both the lower end of the discharge wire 50 and the upper end of the discharge wire 52 which are in a vertical relationship can be achieved at the same time.
[0027]
FIG. 7 is a perspective view showing a fourth embodiment of the present invention. Linear discharge wires 60 and 62 are fixed to the horizontal pipe 12B in the vertical direction, respectively. A cord-shaped restraining means 64 is wound around the lower end of the discharge wire 60 and the upper end of the discharge wire 62 in a figure eight shape. For this reason, even if the break Z occurs at the upper end of the discharge wire 62, the discharge wire 62 is restrained by the ring portion 64A of the restraining means 64, so that it is possible to prevent the discharge wire 62 from falling down and coming into contact with the dust collecting electrode plate. In order to securely hold the shape of the ring portion 64A, it is preferable that the crossing portion 64B of the string be tightened by an appropriate method. According to the fourth embodiment, since no special protective cap is required, it is effective as an emergency treatment.
[0028]
【The invention's effect】
According to the present invention, since the protective cap that wraps around the end of the discharge wire is attached, even when the end of the discharge wire breaks, it is possible to avoid a situation in which the entire apparatus is stopped due to a short circuit with a high probability. In addition, since the protective cap is divided into two parts, there is an advantage that the protective cap can be easily attached to the discharge electrode of the existing electric precipitator.
[Brief description of the drawings]
FIG. 1 is a partial side view showing a first embodiment of a discharge electrode of an electrostatic precipitator according to the present invention.
FIGS. 2A and 2B are diagrams showing both end portions of a discharge wire 14, wherein FIG. 2A is a front sectional view and FIG. 2B is a side sectional view.
FIG. 3 is an exploded perspective view showing a shape of a protective cap 16;
FIG. 4 is a partial cross-sectional view showing a state of connection of a protective cap 16 having a split structure.
FIG. 5 is a conceptual partial side view showing a second embodiment of the present invention.
FIG. 6 is a partial perspective view showing a third embodiment of the present invention.
FIG. 7 is a partial perspective view showing a fourth embodiment of the present invention.
FIG. 8 is a side view showing a general structure of a discharge electrode according to a conventional electric precipitator.
FIG. 9 is a front view for explaining the relationship between a discharge electrode and a dust collecting electrode plate according to a conventional electric dust collecting apparatus.
[Explanation of symbols]
10 discharge electrode, 12 discharge frame, 12A vertical pipe, 12B horizontal pipe, 14 discharge wire, 16 protective cap, 18, 19 projection, 20, 22 ... pin rod, 42 ... discharge wire, 44 ... protective cap, 50, 52 ... discharge wire, 54A, 54B ... band, 60, 62 ... discharge wire, 64 …… Restriction means, X, Y, Z …….

Claims (4)

By fixing both ends of the discharge wire to the discharge frame, in the discharge electrode of the electric precipitator in which the discharge wire is passed over the discharge frame, the end is wrapped around the end of the discharge wire. An electrode for an electrostatic precipitator, which is provided with a protective cap. The discharge wire is a discharge wire having a plurality of protrusions, and the protective cap wraps a base end of at least one protrusion and exposes a front end of the protrusion to the outside. 2. The discharge electrode of the electrostatic precipitator according to 1. The discharge electrode of an electrostatic precipitator according to claim 1, wherein the protection cap has a split structure, and is attached so as to sandwich an end of the discharge wire from both sides. By fixing both ends of the discharge wire to the discharge frame, in the discharge electrode of an electric precipitator that allows the discharge wire to extend vertically to the discharge frame, at the upper end position of the discharge wire, An electrode for an electrostatic precipitator, comprising a restraining means for preventing the discharge wire from falling down when the upper end of the discharge wire is broken.

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