JP3678277B2 - Electric dust collector discharge electrode - Google Patents

Description

[0001]
BACKGROUND 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-scale dry electrostatic 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. 5 is generally employed. The discharge electrode 1 is mainly composed of a conductive discharge frame 2 and a large number of conductive discharge lines 3. The discharge frame 2 is formed by welding vertical pipes 2A and horizontal pipes 2B in a lattice shape. In the illustrated discharge frame 2, a total of 12 lattice frames of 3 × 4 are formed. In each grid frame, three discharge lines 3 are fixed to the horizontal pipe 2B by welding or the like at both ends, and are passed over the discharge frame 2 in the vertical direction. Accordingly, the discharge electrode 1 shown in the figure has a total of 36 discharge lines 3 of 12 × 3. The discharge electrode 1 is suspended through a support 4, and a high voltage is applied by connecting to a power source (not shown). As the discharge line 3, a linear line using a round line or a square line, a band-shaped line, or the like is employed.
[0003]
As shown in FIG. 6A, the discharge electrodes 1 are alternately arranged with the dust collecting electrode plates 5 in the casing of the electrostatic dust collector. 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. Due to this corona discharge, dust in the gas passing through the casing is charged and attracted to and attached to the dust collecting electrode plate 5. The dust adhering to and accumulating on the dust collecting electrode plate 5 is removed from the dust collecting electrode plate 5 by operating a not-shown hammering means provided on the dust collecting electrode plate 5 at predetermined time intervals. In order to stably maintain corona discharge, the discharge electrode 1 is also provided with a striking rod 6. By striking this striking rod 6 separately from the dust collecting electrode plate 5, a discharge wire is provided. The dust adhering to 3 is removed.
In a large dry electrostatic precipitator, several tens to several hundreds of discharge electrodes 1 as described above are attached per unit. Therefore, in terms of the number of discharge lines, thousands of discharge lines 3 are used per unit.
[0004]
By the way, in this type of electrostatic precipitator, when the discharge electrode 1 is beaten, a strong impact stress due to hammering acts on the discharge wire 3 each time. If such impact stress frequently and repeatedly acts during long-term operation, the discharge wire 3 may be fatigued and broken. Then, the broken discharge line is deformed by its own weight, it is possible to contact the dust collecting electrode plate 5 of the adjacent as shown in FIG. 6 (2). Even if only one of the thousands of discharge lines 3 per unit breaks, if the dust collector electrode 5 is touched as described above, a charging abnormality occurs due to a short circuit, and the entire unit is stopped. (For example, refer to Patent Document 1).
[0005]
It is said that such discharge line breakage accidents are caused not only by impact stress due to hammering, but also by the corrosive environment due to the temperature and properties of the gas to be treated and the electrical influence due to energization. Making it difficult. For this reason, it is practically difficult to completely eliminate the discharge line breakage accident.
[0006]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 10-113575
[Problems to be solved by the invention]
The present invention was born under such a background, and the object of the present invention is to improve the above-mentioned problems of the prior art, and to stop the operation of the entire apparatus even when the discharge line breaks. An object of the present invention is to provide a discharge electrode for an electrostatic precipitator that can be avoided with high probability.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the discharge electrode of the electrostatic precipitator according to the present invention is a discharge electrode of an electrostatic precipitator in which both ends of a discharge wire having a plurality of protrusions are fixed to a discharge frame . A protective cap is attached so as to wrap the end portion of the discharge line, wrap the base end portion of at least one protrusion of the discharge line, and expose the tip end of the protrusion to the outside .
[0009]
Further, the discharge electrode of the electrostatic precipitator according to the present invention has the above-described configuration, wherein the protective cap is non-conductive, and a pair of cap members forming a split structure are end portions of the discharge line. It is characterized in that they are coupled by a ridge having an elastic action so as to be sandwiched from both sides .
[0010]
[Action]
According to the present invention, the above-described breakage of the discharge line is likely to occur at the end portion near the fixing portion with the discharge frame, hardly occurs at the middle portion of the discharge line, and a short circuit occurs when the upper end portion of the discharge line is broken. It was made paying attention to being easy to lead to an accident.
That is, by attaching a protective cap that wraps around the end of the discharge line, even if the end of the discharge line breaks, the movement of the broken discharge line is constrained by the presence of the protective cap, so Contact with the dust electrode plate can be prevented. For this reason, it can be avoided with high probability that the situation of the operation stop of the whole apparatus due to a short circuit will occur.
[0011]
In addition, the protective cap wraps the end portion of the discharge line having a plurality of protrusions, wraps the base end portion of at least one protrusion of the discharge line, and the tip of the protrusion is exposed to the outside. The discharge action of the protrusion is not hindered. Further, the protrusion itself plays a role of preventing the protective cap from falling.
[0012]
Further, the protective cap is non-conductive, and a pair of cap members forming a split structure are joined by a hook having an elastic action so that the ends of the discharge line are sandwiched from both sides. . For this reason, the coupling | bonding of a cap member is realizable by one-touch.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a partial side view showing an embodiment of a discharge electrode of an electric dust collector according to the present invention. The discharge electrode 10 is mainly composed of a conductive discharge frame 12 and a large number of conductive discharge lines 14. The discharge frame 12 is formed by welding steel vertical pipes 12A and horizontal pipes 12B in a grid shape, and each grid frame has a plurality of (seven in the illustrated example) discharge wires 14 at both ends. The part is fixed to the horizontal pipe 12B by welding and is passed to the discharge frame 12 in the vertical direction. Protective caps 16 are attached to both ends of each of the discharge lines 14, 14,.
[0014]
FIG. 2 shows both end portions of the discharge wire 14, wherein (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 line 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. Yes. That is, in FIG. 2 (1), the tip of the protrusion 18 formed on the left side faces a left dust collecting electrode plate (not shown), and the tip of the protrusion 19 formed on the right side is a right dust collecting electrode (not shown). It is suitable for the board. Therefore, when a high voltage is applied to the discharge line 14, a corona discharge current flows from the tips of the protrusions 18 and 19, and a uniform electric field with a predetermined gradient is formed.
[0015]
A pin bar 20 is fixed to the lower end side of the upper discharge wire 14 by welding, and the lower end of the pin bar 20 is fixed to the upper surface of the horizontal pipe 12B by welding. Further, a pin bar 22 is fixed by welding to the upper end side of the strip of the lower discharge wire 14, and the upper end of the pin bar 22 is inserted into a hole formed in the lower surface of the horizontal pipe 12B and fixed by welding. With such a welding and fixing structure of the horizontal pipe 12B and the discharge line 14, a high voltage from the high voltage power source 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 line 14, protective caps 16 are provided so as to wrap each end. In FIG. 2, only the protective cap 16 attached to the upper end portion of the lower discharge line 14 is shown, and the protective cap 16 attached to the lower end portion of the upper discharge line 14 is omitted. The protective cap 16 is made of a non-conductive synthetic resin, and is attached so as to wrap around the entire range of the end portion of the discharge line that is expected to break. In the state shown in FIG. 2, the portion of the pin bar 22 sandwiched between the lower surface of the horizontal pipe 12 </ b> B and the upper end of the strip of the lower discharge line 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 surely wrap around the range that is most likely to break.
[0017]
As shown in FIG. 3, the protective cap 16 has a split structure composed of caps 16 </ b> A and 16 </ b> B. The cap 16A includes a semi-cylindrical pin rod accommodating portion 24 for enclosing the pin rod 22, and flanges 26 provided on the left and right sides of the pin rod accommodating portion 24. The flange 26 has a total of six holes 28. Is provided. The cap 16 </ b> B includes a strip plate housing portion 30 for wrapping the strip plate portion of the discharge wire 14, and flanges 32 provided on the left and right sides of the strip plate housing portion 30, and the flange 32 has a position corresponding to the hole 28. In total, six ridges 34 are provided. Further, the cap 16B is provided with projections 18 of the discharge line 14 and through portions 36 and 38 of the projection 19.
[0018]
The cap 16A and the cap 16B are brought close to each other so as to sandwich the upper end portion of the discharge line 14 from both sides. From the state shown in FIG. 4A, the flange 34 provided on the flange 32 is inserted into the hole 28 of the flange 26. As a result, the flange 26 and the flange 32 can be coupled with one touch as shown in FIG. As a result, the protective cap 16 wraps around the pin rod 22 at the upper end of the discharge line 14, the upper end portion of the strip plate, and the base end portions of the two protrusions 18 and 19 provided at the upper end portion of the strip plate. As shown in FIG. 2A, the protrusion 18 or 19 penetrates the through part 36 or 38, respectively, and the tip part 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 protrusions 18 and 19 at this position is not hindered. Further, the protrusions 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 portion of the discharge line 14 encased by the protective cap 16 is broken for some reason. Typical positions of the expected fracture are shown as X and Y in FIG. The break X is a break of the band plate portion, and the break Y is a break of the pin bar 22. Actually, there are many breaks Y, and the possibility of the break 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. Therefore, to prevent the discharge line 14 upper end is fracture surface collapses by its own weight, it can be avoided collecting electrode plates contact phenomenon as shown in FIG. 6 (2). Therefore, the worst situation of the operation stop of the entire apparatus due to a short circuit can be avoided. In addition, the conduction between the upper horizontal pipe 12B and the discharge line 14 whose upper end is a fractured surface is impaired by the breaks X and Y, but the lower end of the broken discharge line 14 is electrically connected to the lower horizontal pipe (not shown). Therefore, the broken discharge wire 14 still exhibits a normal discharge function.
[0020]
As shown in FIG. 1, the protective cap 16 is similarly attached to the lower end portion of the discharge line 14. However, when the lower end portion of the discharge wire 14 is broken, most of the discharge wire 14 is suspended from above by its own weight, so that the lower end portion of the broken discharge wire may come into contact with the dust collecting electrode plate. Relatively low. Accordingly, in some cases, the attachment of the protective cap 16 on the lower end side can be omitted.
[0021]
Further, as described above, the breakage hardly occurs at the intermediate portion of the discharge wire 14. Therefore, in the present invention, even if only the upper end portion of the discharge line 14 is wrapped with the protective cap 16, it is possible to avoid the situation of the operation stop of the entire apparatus due to the breakage of the discharge line with a very high probability.
[0022]
In this embodiment , the protective cap 16 has a split structure and can be attached so that the upper end of the discharge wire 14 is sandwiched from both sides, so that not only the newly installed electrostatic dust collector but also the existing electrostatic dust collector can be used. The protective cap 16 can be easily attached to the discharge electrode. Further, the protective cap 16 can be easily removed from the discharge electrode as necessary.
[0023]
In this embodiment , the protective cap 16 is made of non-conductive synthetic resin. For this reason, even if the broken discharge wire 14 is bent while being held by the protective cap 16 at the end and is in contact with the dust collecting electrode plate, the non-conductive protection is provided between the discharge wire end portion and the dust collecting electrode plate. A layer of cap 16 is 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, it can be made of a conductive metal in consideration of heat resistance.
[0024]
It is preferable that the protective cap 16 is formed of a transparent material and has a structure in which dust does not enter inside using a packing. This is convenient because it is possible to visually determine the state of breakage of the internal discharge lines simply by wiping the outer surface of the protective cap 16 during maintenance and inspection.
[Brief description of the drawings]
FIG. 1 is a partial side view showing an 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 line 14; FIG. 2A is a front sectional view, and FIG. 2B is a side sectional view;
3 is an exploded perspective view showing the shape of the protective cap 16. FIG.
FIG. 4 is a partial cross-sectional view showing a coupling state of the protective cap 16 having a split structure.
FIG. 5 is a side view showing a general structure of a discharge electrode according to a conventional electrostatic precipitator.
FIG. 6 is a front view for explaining the relationship between a discharge electrode and a dust collecting electrode plate according to a conventional electric dust collector.
[Explanation of symbols]
10 ......... Discharge electrode, 12 ......... Discharge frame, 12A ......... Vertical pipe, 12B ......... Horizontal pipe, 14 ...... Discharge wire, 16 ......... Protective cap, 18, 19 ......... Protrusions, 20, 22 ... Pin stick.

Claims (2)

In a discharge electrode of an electrostatic precipitator in which both ends of a discharge line having a plurality of protrusions are fixed to a discharge frame, the discharge line includes an end of the discharge line and a base end of at least one protrusion of the discharge line A discharge electrode for an electrostatic precipitator, which is provided with a protective cap that encloses the protrusion and exposes the tip of the protrusion to the outside . The protective cap is non-conductive, and a pair of cap members forming a split structure are joined by a hook having an elastic action so as to sandwich an end portion of the discharge line from both sides. The discharge electrode of the electrostatic precipitator according to claim 1.

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