JP5047107B2 - Insulator contamination prevention device and electric dust collector - Google Patents

Description

  The present invention relates to a rotary electric dust collector or the like that collects (removes) fine dust, mist, etc. (hereinafter referred to as “dusts”) present in an air current using a dust collecting element to which a high voltage is applied. The present invention relates to an insulator contamination prevention device having a function of preventing adhesion of dust to an insulating means such as an insulator for holding a high voltage electrode.

  Conventionally, when an air flow containing dust flows into an insulator supporting a high-voltage electrode such as an electrostatic precipitator, the dust adheres to the insulator surface, resulting in a decrease in insulation, causing creeping discharge and high-voltage current to be short-circuited. It is known that problems such as the occurrence of problems occur.

Therefore, in order to prevent such dust from adhering to the insulator, an electric field generated at a narrow interval between the high-voltage electrode plate and the seat plate before the air flow including dust reaches the insulator supporting the high-voltage electrode. The dust is collected (removed) on the seat plate side (grounding electrode) by using a protective umbrella body that prevents contamination of the insulator and prevents dust from directly adhering to the insulator, and this protective umbrella body and the dust collection chamber A technique for preventing dust from adhering to the insulator by an electric field generated between the two is known (for example, see Patent Document 1).
Japanese Patent No. 3634178

  However, when collecting dust of normal concentration contained in the airflow, the occurrence of insulator contamination can be suppressed by taking the above-mentioned preventive measures, but electricity that collects relatively high concentration of dust. In the case of a dust collector, for example, an electric dust collector equipped with a function of collecting (removing) dust collected in the dust collector during operation, it is relatively used for applications with a long operation time. In the case of an electrostatic precipitator with a high dust collection load, a very small amount of dust accumulates around the insulator as time passes, making it difficult to suppress the adhesion of dust to the insulator surface. Dirt was not reliably prevented.

  If dust adheres to the insulator surface in this way, problems such as the occurrence of creeping discharge and short-circuiting of the high-voltage current due to the insulation deterioration of the insulator occur, resulting in the suspension of operation of the electrostatic precipitator. The problem of falling will occur.

  Furthermore, if the electrostatic precipitator is shut down, the high voltage electrode must be taken out from the main body of the precipitator to remove the dust adhering to the insulator, which takes time and labor for maintenance. End up.

  Therefore, in consideration of the above circumstances, the present invention has an inexpensive and simple structure, and even when high-concentration dust is collected or when dust is collected for a long time, It aims at providing the insulator contamination prevention apparatus which can suppress adhesion.

The insulator contamination preventing apparatus of the present invention comprises an insulator for supporting a high voltage electrode composed of a charging side mounting plate portion and a grounding side mounting plate portion facing each other in an insulated state, and a charging side periphery and a ground side periphery of the insulator. In the insulator contamination prevention device comprising a pair of inner and outer conductive protection cylinders arranged so as to surround independently, the pair of conductive protection cylinders are each formed in a bottomed cylindrical shape, The bottom of one conductive protection cylinder surrounding the charging side periphery of the insulator is fastened together with the insulator on the charging side mounting plate so as to be sandwiched between the charging side mounting plate and the insulator, and the insulator The bottom of the other conductive protection cylinder surrounding the ground side is fixed to the ground side mounting plate portion together with the insulator so as to be sandwiched between the ground side mounting plate portion and the insulator, and the conductive protection cylinder the cylindrical body opposite the tip portion between the predetermined insulation隔以of With wrapping to the inner and outer layers together in a spaced apart condition, and characterized by generating an electric field to deposit dust types included in the air flow by the application of a voltage to the high voltage electrode to said pair of electrically conductive protective pipe To do.

According to the configuration described in claim 1, a voltage is applied directly to the high-voltage electrode, thereby generating an even electric field between the front ends of the pair of conductive protective cylinders that are wrapped with each other. In addition to being able to adhere, some of the charged dust attracted toward the insulator by this electric field can adhere to the surface of the conductive protection cylinder, and the adhesion of dust to the insulator can be suppressed. Thus, the insulator can always be kept in a good insulating state. In addition, by surrounding the insulator with a pair of conductive protective cylinders, it is possible to shield the insulator surface from the surrounding airflow, and to prevent the dust contained in the airflow from directly touching the insulator. Can do. In addition, the pair of conductive protection cylinders can be easily fixed to each mounting plate part together with the insulator using each bottom part, and a large contact area can be secured, and the pair of conductive protection cylinders In addition to being able to apply a stable high voltage to the body, it is possible to stabilize the mounting posture of the pair of conductive protective cylinders and to keep a predetermined insulation interval between the pair of conductive protective cylinders constant be able to.

Further, the insulator contamination preventing apparatus according to claim 2 is configured so that at least one conductive protective cylinder surrounding the charging side of the pair of conductive protective cylinders at the opposite end of the pair of conductive protective cylinders. The portion is formed in a sawtooth shape.

According to the configuration described in claim 2 , at least one of the conductive protection cylinders surrounding the periphery of the charging side of the pair of conductive protection cylinders has a saw-tooth shape. By being able to form a plurality of pointed ends and concentrating the electric field on the ends, the electric field effect can be further improved, and the effect of preventing the adhesion of dust to the insulator is improved. Can do.

In addition, in the insulator contamination prevention apparatus according to claim 3 , one of the conductive protection cylinders surrounding the charging side of the insulator is located on the inner side of the other conductive protection cylinder surrounding the earthing side of the insulator. It is arranged.

According to the structure of Claim 3 , the ratio of the dust contained in an airflow is arranged by arrange | positioning one electroconductive protection cylinder surrounding the charge side periphery of an insulator inside the other electroconductive protection cylinder. The area of the other conductive protection cylinder that collects the charged potential dust with a large amount can be secured wider than the area of the one conductive protection cylinder that collects the dust that lost the potential.

Moreover, this invention can be made into the electrical dust collector provided with the insulator contamination prevention apparatus in any one of Claim 1 thru | or 3 , and fixed to the several rotating electrode plate mutually arrange | positioned. It can also be set as the electric dust collector provided with an electrode plate.

  The insulator contamination prevention apparatus of the present invention has an inexpensive and simple structure, and suppresses adhesion of dust to the insulator even when high concentration dusts are collected or when dusts are collected for a long period of time. can do.

  Next, an insulator contamination preventing apparatus according to an embodiment of the present invention will be described with reference to the drawings. The following embodiments are preferred specific examples of the present invention and may have various technically preferable limitations. However, the technical scope of the present invention is not limited to the description of the present invention. As long as it is not limited to these embodiments.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of an insulator contamination preventing apparatus according to the present invention will be described with reference to the drawings.

(Overall configuration of electric dust collector)
First, based on FIG.1 and FIG.2, the structure of the electric dust collector which mounts the insulator contamination prevention apparatus which concerns on this invention is demonstrated.

  FIG. 1 is a perspective view of an electric dust collector equipped with an insulator contamination preventing apparatus according to an embodiment of the present invention, and FIG. 2 is a diagram showing a height of the electric dust collector equipped with an insulator contamination preventing apparatus according to an embodiment of the present invention. It is a perspective view of a voltage electrode unit.

  In FIG. 1, an electrostatic precipitator 1 according to the present invention is provided with top plates 3, 3 at the upper edges of a pair of outer frames 2, 2 that are opposed to each other in a separated state. In between, as shown in FIG. 2, the high voltage electrode unit 4 is arrange | positioned.

(Inside structure of outer frame 2)
The high voltage electrode unit 4 is transmitted with a rotational driving force from a driving source such as a motor (not shown) to a horizontal rotating shaft 5 penetrating substantially at the center thereof.

  A plurality of rotating electrode plates 6, 6... Are fixed to the horizontal rotating shaft 5 integrally with the horizontal rotating shaft 5 at intervals, and each rotating electrode plate is rotated by a rotational driving force from a driving source such as a motor. 6, 6 ... rotate. Further, a brush 7 is in contact with a portion protruding from the outer frame 2 on the front side (left side in the figure) of the horizontal rotary shaft 5, and the rotary electrode plates 6, 6. Yes.

  In FIG. 2, the rotating electrode plates 6, 6... Are shown as two-dot chain lines for convenience, but nine in total are arranged in parallel. Further, a plurality of fixed electrode plates are interposed between the rotary electrode plates 6, 6... Via shaft-like conductive spacers 8 supported by escape holes 2a formed at the four corners of the outer frames 2, 2. 9, 9... Are arranged. Further, an annular band 10 is interposed in each interval between the rotary electrode plates 6, 6... (Only one place is shown in FIG. 2).

  The fixed electrode plates 9, 9... Are arranged side by side with a constant interval by four conductive spacers 8, 8.... In the present embodiment, the eight fixed electrode plates 9, 9.. 5 are arranged side by side. Further, a positive high voltage is applied to each fixed electrode plate 9, 9 ... from a voltage supply means (not shown). Further, a plurality of needle-like charging electrodes 11 are attached to each fixed electrode plate 9, 9... By welding or caulking. Further, the upper edges of the fixed electrode plates 9, 9... Are opened so that the tip of the charging electrode 11 protrudes and discharge can be performed efficiently.

  In the state where the annular band 10 is positioned in the notch space portion 9a extending directly below from the vicinity of the center of each fixed electrode plate 9, 9 ..., the same number of 8 pieces as the fixed electrode plates 9, 9 ... are arranged. Yes. Further, the width of the annular band 10 is substantially equal to the adjacent interval between the rotary electrode plates 6, 6..., And each fixed electrode plate is located at a position (intermediate position) separated by a distance approximately half the width of the annular band 10. 9, 9 ... are located. Further, each annular band 10 includes a driving pulley 12 provided on the horizontal rotating shaft 5 and a driven pulley provided on a belt shaft 13 disposed in parallel to the horizontal rotating shaft 5 below the electrostatic precipitator 1. 14 is constructed so as to be able to rotate and move in an appropriate tension state. In addition, the annular band 10 is provided with round holes 10a at regular intervals in the longitudinal direction at the center of the width thereof. A semicircular protrusion (not shown) formed on the drive pulley 12 is fitted into the round hole 10a in a sprocket shape, and a transmission driving force acts on each annular band 10 by this sprocket structure. Further, a transport dust removing squeegee 15 having a sword-shaped tip is disposed in contact with (or close to) the surface of all the annular bands 10 below the annular band 10 and in the immediate vicinity of the driven pulley 14. ing.

(Outside structure of outer frame 2)
The electrostatic precipitator 1 including the outer frames 2 and 2 is grounded. Further, grounding side mounting plate portions 16 and 16 are fixed to the outer wall surfaces of the outer frames 2 and 2 so as to sandwich the horizontal rotation shaft 5 therebetween. Further, charging-side mounting plate portions 17 and 17 are supported at the tips of the conductive spacers 8 that protrude outward from the outer frames 2 and 2.

  The ground-side mounting plate portions 16 and 16 and the charging-side mounting plate portions 17 and 17 are arranged so as to have a vertical relationship with respect to the horizontal rotation shaft 5, and are horizontally oriented from the outer wall surfaces of the outer frames 2 and 2. Are provided with flange-like facing surface portions 16a, 16a and facing surface portions 17a, 17a.

  Each facing surface portion 16a and the facing surface portion 17a constitute a high voltage electrode including a charge side electrode and a ground side electrode. Further, in order to support the high voltage electrode in an insulated state between each facing surface portion 16a and the facing surface portion 17a (as shown in FIG. 3), an insulator having a cylindrical electrical insulation property is provided. 18 (only one is shown) is fixed via screws 19 and 20.

  Around each insulator 18, insulator contamination preventing devices 23, 23... Comprising a pair of conductive protection cylinders 21, 22 for preventing the adhesion of dusts are attached.

  The conductive protection cylinders 21 and 22 are cylindrical cylinders made of conductive material, and are opposed to each other inside and outside in a state where the opposite end portions are separated by a predetermined insulation interval or more.

  In the present embodiment, except for the brush 7, the grounding side mounting plate parts 16, 16, the charging side mounting plate parts 17, 17, the lever 18 (, 18...), And the insulator contamination preventing devices 23, 23. Are arranged in the same manner on the outer frame 2 on the back side.

(Example)
Next, the flow of dust-containing air (airflow) in the electrostatic precipitator 1 will be described.

  As shown by the arrow A in FIGS. 1 and 2, the dust-containing air flows in from the upper side to the lower side of the electrostatic precipitator 1 by the suction action of a blower (not shown).

  At this time, when the dusts in the dust-containing air are charged to the positive side by the high voltage corona discharge in the electrostatic precipitator 1, particularly from the tip, the rotating rotating electrode plates 6, 6. Since they are connected, positively charged dusts are collected on the rotating electrode plates 6, 6.

  Normally, the dust-containing air circulates only from the upper side to the lower side as indicated by an arrow A inside the outer frames 2 and 2, and the outflow of the dust-containing air to the outside of the outer frames 2 and 2 If the frames 2 and 2 are closed without any gaps, they will not flow out.

  However, the conductive spacers 8, 8... For attaching the fixed electrode plates 9, 9... To the outer frames 2 and 2 penetrate the escape holes 2a across the insulating space. Cannot be shielded.

  In particular, when collecting high-concentration dust or operating for a long period of time, dust-containing air flows out from the escape hole 2a to the outside of the outer frame 2, and dust contained in the dust-containing air is collected. , It will float around the insulator 18.

  Therefore, the dusts floating around the insulator 18 are attracted by the electric field generated between the conductive protection cylinders 21 and 22 covering the insulator 18 and captured on the surfaces of the conductive protection cylinders 21 and 22. Since they are collected (removed), the adhesion of dust to the insulator 18 can be suppressed, and the insulator 18 can always be kept in a good insulating state.

  Specifically, the insulator 18 which is an insulator is in contact with the charging side mounting plate portion 17 and the ground side mounting plate portion 16 in a state of being sandwiched between the charging side mounting plate portion 17 and the ground side mounting plate portion 16. It is fixed to the plate parts 16 and 17.

  The conductive protection cylinders 21 and 22 are cylindrical, have a thickness of 1 mm or less and are made of stainless steel or the like, and cover the periphery of the insulator 18 concentrically. In addition, the cross-sectional shape of the conductive protection cylinders 21 and 22 may be a polygon or an ellipse, and the selection thereof is arbitrary.

  At this time, among the conductive protection cylinders 21 and 22, the charge side conductive protection cylinder 22 is attached in contact with the charge side attachment plate portion 17, and the ground side conductive protection cylinder 21 is connected to the ground side attachment plate portion. 16 is attached in contact with.

  In addition, about the attachment (fixation) method of each electroconductive protection cylinder 21 and 22 to the attachment board part 16.17, it can fix using well-known means, such as screwing, caulking, and welding.

  Further, the diameter of the charge side conductive protection cylinder 22 is set to a predetermined size or more than the diameter of the insulator 18 and is set to a diameter (inner diameter) which is not affected by creeping discharge generated on the surface of the insulator 18 at least. The

  On the other hand, the diameter of the ground-side conductive protective cylinder 21 positioned outside the charge-side conductive protective cylinder 22 is separated from the diameter of the charge-side conductive protective cylinder 22 by a predetermined insulation interval X or more. Is set to

  For example, if a voltage of 10,000 V is applied to the high voltage electrode, the insulation interval X needs to be 10 mm or more, but the insulation interval X is the applied voltage. It depends on. In the present embodiment, the wrap margin Y at the opposite end of the ground side conductive protective cylinder 21 and the charge side conductive protective cylinder 22 is brought into space by a voltage supply means (not shown). A uniform electric field is generated. At this time, the wider the lapping allowance Y, the better the performance of collecting (removing) dusts. Therefore, it is better to take as much as possible, but the tip of the charge side conductive protection cylinder 22 and the ground side mounting plate The distance Y1 to the portion 16 and the distance Y2 between the tip of the ground side conductive protective cylinder 21 and the charge side mounting plate portion 17 need to be equal to or greater than the insulation distance.

  Therefore, the dusts flowing out of the escape hole 2a to the outside of the frame 2 and floating around the insulator 18 are dusts having a positive potential charged by the electrostatic precipitator 1 (see black circles in FIG. 3). However, dust that has been once collected by the electrostatic precipitator 1 but has lost its electric potential due to loss of electric potential (see white circles in FIG. 3) is mixed.

  Among the dusts having these attributes, dusts charged to a positive potential (see the black circles in FIG. 3) are attracted to a uniform electric field generated in the covered portion between the conductive protection cylinders 21 and 22. Thus, it can be collected (removed) on the lapping surface of the ground side conductive protective cylinder 21.

  In contrast, dusts that have lost their potential (see the white circles in FIG. 3) are attracted to a uniform electric field and collected (removed) on the surface of the charge-side conductive protective cylinder 22. That is, a large amount adheres mainly to the surface of the wrapping charge side conductive protection cylinder 22.

  From the above, the dust floating around the insulator 18 is attracted by the uniform electric field generated between the conductive protection cylinders 21 and 22, and the conductive protection cylinders 21 and 22 are wrapped. Therefore, dust can be prevented from adhering to the surface of the insulator 18 and the insulator 18 is not contaminated.

  Of the dusts collected (removed) on the surfaces of the conductive protection cylinders 21 and 22, very fine particles adhere to the surfaces of the conductive protection cylinders 21 and 22, Dusts with large particle diameters start to sag downwards and eventually accumulate on the ground side mounting plate. However, since the amount is extremely small, maintenance can be performed by performing simple cleaning once a year. Does not take much time.

(Modification 1)
FIG. 4 is a cross-sectional view of a main part showing a first modification of the insulator contamination preventing apparatus according to one embodiment of the present invention.

  In the insulator contamination prevention device 33 shown in the first modification, each of the conductive protection cylinders 31 and 32 has a substantially bottomed cylindrical shape, and a mounting hole having a diameter of about several millimeters is formed at the center of the bottom surface. It is provided and fastened together with the insulator 18 to the mounting plates 16 and 17 by screws 19 and 20.

  Thereby, the bottom surface of the charge side conductive protection cylinder 32 is fixed with the screw 20 so as to be sandwiched between the charge side mounting plate portion 17 and the insulator 18, and the bottom surface of the ground side conductive protection cylinder body 31 is fixed to the ground side mounting plate portion. The conductive protective cylinders 31 and 32 can be easily attached to the attachment plates 16 and 17 simply by being fixed with screws 19 so as to be sandwiched between the insulator 16 and the insulator 18.

  In addition, since each of the conductive protection cylinders 31 and 32 has a bottomed cylindrical shape, a wide contact area between each of the conductive protection cylinders 31 and 32 and each of the mounting plate portions 16 and 17 can be secured. A stable high voltage can be applied to the conductive protection cylinders 31 and 32.

  Furthermore, since the conductive protective cylinders 31 and 32 are not inclined with respect to the mounting plate portions 16 and 17 and the posture is stabilized, the insulation on the circumference at the wrap margin Y of the conductive protective cylinders 31 and 32 is achieved. The interval X can always be kept constant.

  In addition, there are several discharge holes (diameter of about several mm) for discharging dust collected (removed) at the bottom of the ground side conductive protection cylinder 31 (in the case of FIG. 4) located on the lower side. It is possible to prevent the dust from accumulating for a long period of time and maintain a good state at all times.

(Modification 2)
FIG. 5 is a cross-sectional view of a main part showing a second modification of the insulator contamination preventing apparatus according to one embodiment of the present invention.

  The insulator contamination prevention device 43 shown in the modified example 2 is held on the insulator 18 in a state in which the charged-side conductive protective cylinder 42 having a bottomed cylindrical shape is separated from the charge-side mounting plate 17 by a predetermined distance Y3 (for example, adhesion Or crimping).

  At this time, the diameter of the charge side conductive protective cylinder 42 needs to be larger by about several mm than the diameter of the insulator 18.

  Since the charge-side conductive protection cylinder 42 is separated from the charge-side mounting plate portion 17 by a predetermined distance Y3, a high voltage is not directly applied to the charge-side conductivity protection cylinder 42, and is not applied to the surface of the insulator 18. A high voltage is generated between the conductive protection cylinders 21 and 42 by the generated surface potential.

  The distance Y3 between the charging side mounting plate portion 17 and the charging side conductive protection cylinder 42 is, for example, about 10 mm when the voltage application is 10,000 volts.

  This is because if the distance Y3 is too close, the electric field generated between the conductive protection cylinders 21 and 42 is strengthened by the surface potential received from the insulator 18, and the insulation interval X between the conductive protection cylinders 21 and 42 is increased. This is because it is difficult to reduce the size of the apparatus. On the other hand, if the distance Y3 is too long, the surface potential received from the insulator 18 is lowered, and the dust collection (removal) effect is weakened.

  The setting of the insulation interval X depends on the high voltage between the conductive protection cylinders 21 and 42 generated by the surface potential of the insulator 18.

  For example, the high voltage between the conductive protection cylinders 21 and 42 generated by the surface potential is lower than the high voltage generated by direct application, for example, about 3 KV. The insulation interval (dimension X in the figure) may be about 4 to 5 mm, and the diameter of the covering conductive protective cylinders 21 and 42 (here, the ground side conductive protective cylindrical body 21 is shown) should be reduced. Therefore, the insulator contamination prevention device 43 can be downsized as compared with the case where a high voltage is directly applied.

(Modification 3)
FIG. 6 is a cross-sectional view of a main part showing a third modification of the insulator contamination preventing apparatus according to one embodiment of the present invention.

  In the insulator contamination prevention device 53 shown in the third modification, the opposite end portion of the charging side conductive protection cylinder 52 is formed in a serrated uneven shape.

  This is because the tip of the opposite side of the charge side conductive protective cylinder 52 has a sawtooth shape to form a pointed end, generates an unequal electric field, and concentrates the electric field on the end, thereby reducing the electric field effect. It is possible to further increase the amount of dust to be collected (removed) by the conductive protection cylinders 21 and 52.

  In addition, the sawtooth shape of the opposite side tip portions of the conductive protection cylinders 21, 52 facing each other may be only the charge side conductive protection cylinder 52, but the charge side conductive protection cylinder 52 and the ground side conductivity are not limited. You may form in both the protection cylinders 21. FIG.

  Although the insulator contamination prevention device 23 of the electrostatic precipitator 1 of the electrostatic precipitator has been described above, it may be used in 18 places of the insulator of the voltage supply means (not shown), or used in each part of a general electrostatic precipitator. May be.

  4 to 6, the same reference numerals are given to the same components as those in the above embodiment, and the description thereof is omitted.

  As described above, according to the insulator contamination preventing apparatus 23 (33, 43, 53) of the present invention, when using the insulator contamination preventing apparatus 23 having an inexpensive and simple structure, high-concentration dusts are collected, Even when the operation is relatively long and the dust collection load is high, dust is collected by the uniform electric field generated between the conductive protection cylinders 21 and 22 of the conductor before reaching the insulator 18. As a result, adhesion of dusts to the insulator 18 can be suppressed, occurrence of problems such as deterioration of insulation, creeping discharge, and short circuit of high-voltage current can be prevented, and maintenance can be greatly reduced.

  Further, by covering the periphery of the insulator 18 with the conductive protection cylinders 21 and 22, the surface of the insulator 18 can be shielded from the surrounding air current, and the dust contained in the air current directly touches the insulator 18. This can be suppressed, and the effect of preventing dust from adhering to the insulator 18 can be further improved.

  Therefore, maintenance such as cleaning of the insulator 18 can be greatly reduced, and stable operation can be ensured.

It is a perspective view of the electric dust collector which mounts the insulator contamination prevention apparatus which concerns on one Embodiment of this invention. It is a perspective view of the high voltage electrode unit in the electrostatic precipitator carrying the insulator pollution control device concerning one embodiment of the present invention. It is sectional drawing of the principal part in the insulator contamination prevention apparatus which concerns on one Embodiment of this invention. It is sectional drawing of the principal part of the modification 1 in the insulator contamination prevention apparatus which concerns on one Embodiment of this invention. It is sectional drawing of the principal part of the modification 2 in the insulator contamination prevention apparatus which concerns on one Embodiment of this invention. It is sectional drawing of the principal part of the modification 3 in the insulator contamination prevention apparatus which concerns on one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electric dust collector 16 ... Grounding side mounting plate part 17 ... Charging side mounting plate part 18 ... Insulator 21 ... Grounding side electroconductive protection cylinder 22 ... Charge side electroconductive protection cylinder 23 ... Insulator contamination prevention apparatus

Claims (5)

An insulator that supports the high-voltage electrode composed of the charging-side mounting plate and the ground-side mounting plate facing each other in an insulated state, and is arranged so as to surround the charging-side periphery and the ground-side periphery of the insulator independently. In an insulator contamination prevention apparatus comprising a pair of inner and outer conductive protective cylinders,
Each of the pair of conductive protection cylinders is formed in a bottomed cylindrical shape, and the bottom of one conductive protection cylinder surrounding the charge side of the insulator is sandwiched between the charge side mounting plate and the insulator. In this way, the bottom of the other conductive protective cylinder surrounding the ground side of the insulator is fixed to the charging side mounting plate portion together with the insulator so that the bottom portion is sandwiched between the ground side mounting plate portion and the insulator. Fastened together with the insulator on the ground side mounting plate,
The opposite end portions of the conductive protection cylinder are wrapped in two layers inside and outside in a state of being separated by a predetermined insulation interval or more, and dust contained in the airflow is applied to the high voltage electrode by applying a voltage to the high voltage electrode. An apparatus for preventing insulator contamination, which generates an electric field to be attached to the conductive protective cylinder. Among the opposing side tip portions of the pair of conductive protection cylinders , at least the opposite side tip portion of one conductive protection cylinder surrounding the periphery of the charging side of the insulator is formed in a sawtooth shape. The insulator contamination prevention apparatus according to claim 1. One of the conductive protective pipe surrounding a charged side periphery of said insulator is claim 1 or 2, characterized in that it is arranged on the inner side than the other conductive protective pipe surrounding the ground around the insulator The insulator contamination prevention apparatus as described in 1. Electrostatic precipitator characterized by comprising the insulator pollution control device according to any one of claims 1 to 3. The electrostatic precipitator according to claim 4, comprising a plurality of rotating electrode plates and fixed electrode plates arranged alternately .

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