JPH0424110B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to an electrostatic precipitator in which the dielectric strength of an insulator supporting a high-voltage side electrode is increased.

[Prior art and its problems] Electrostatic precipitators are applied, for example, to tunnel air cleaning and ventilation equipment that uses the air inside an automobile road tunnel as the gas to be treated. The air inside a motorway tunnel is contaminated with many submicron-sized suspended particles such as smoke emitted from automobiles, dust generated by the abrasion of tires and road asphalt generated as automobiles drive, and the like. As a method of purifying the contaminated air inside the tunnel, an electrostatic precipitator is installed in a detour tunnel inside the tunnel leading to the roadway, and the contaminated air extracted from the roadway is purified by the electrostatic precipitator and returned to the roadway. A device that blows air has been developed.

Next, an overview of ventilation equipment employing this electrostatic precipitator will be explained with reference to FIG. In the figure,
1 is a detour tunnel that leads to the road inside the tunnel,
An electrostatic precipitator body 2 and a blower 3 are installed in the tunnel 1 on the downstream side thereof. The electrostatic precipitator main body 2 has a casing 4, and is provided with opening/closing dampers 5 and 6 on the inlet and outlet sides of the casing 4, respectively, and a charging unit 8 and a charging unit 8 that receive power from a high-voltage power supply 7 are provided inside the casing 4. A dust collection unit 9 is installed. As a result, during operation, the contaminated air A that is sucked into the electrostatic precipitator main body 2 from the upstream side by the blower 3 is transferred to the electrostatic precipitator main body 2. The suspended particles contained therein are collected as dust on the dust collection electrode of the dust collection unit 9, and as a result, the purified air A' is sent downstream through the blower 3. In order to separate and recover the dust collected on the dust collection electrode, on the downstream side of the dust collection unit 9, there are a plurality of air blow nozzles 10 that inject compressed air for dust removal toward the dust collection electrode. is arranged, and a compressor 1 is installed in this air blow nozzle 10.
1, and on the other hand, a dust discharge plenum 13 is defined at the bottom of the casing of the electrostatic precipitator main body 2, and this plenum 13
One end of a pipe 16 with a dust separation and recovery device 14 such as a bag filter or cyclone installed in the middle is connected to the other end of the pipe 16, and a suction fan 1 is connected to the other end of the pipe 16.
Connect the suction end of No.5. In addition, the reference numeral 17 in the figure is the opening/closing drive part of the dampers 5 and 6, 18 is the main valve provided in the middle of the pipe 12, and 19 is the dust discharge plenum 13.
This is an opening/closing damper installed on the exit side of the

Next, the dust dust removal and dust collection operations with the above configuration will be explained based on FIGS. 2 and 3. First, during dust collection operation, the compressor 11 of the pipe 12 and the suction fan 15 of the pipe 16 are both stopped as shown in FIG. 2, and in this state, the electrostatic precipitator body 2 opens the dampers 5 and 6, It receives power from the power supply device 7 to collect dust from the gas to be treated. If this dust collection operation continues for a certain period and a considerable amount of dust has been collected and deposited on the dust collection electrode, the dust adhering to the dust collection electrode will be brushed off based on the cleaning command. Collection will take place. In this case, first stop the power supply to the blower 3 and high-voltage power supply device 7 shown in FIG. 1, then start the compressor 11 and suction fan 15 as shown in FIG. The dampers 5 and 6 on the inlet and outlet sides of the casing are closed, and the main valve 18 of the pipe 12 and the opening/closing damper 19 of the dust discharge plenum 13 are opened to start the dust dust removal and collection operation. That is, the gas that is pressurized and sent from the air blow nozzle 10 through the piping 12 is ejected at a wind speed close to the speed of sound toward the dust collection electrode that constitutes the dust collection unit 9, and is deposited on the electrode. Brush off the dust. The dust collected on the dust collection electrode is aggregated and coarsened, and the coarse particle dust that is blown off from the electrode is transferred to the air blow nozzle 10.
Airflow B blows out into the casing from
The dust is dispersed in this carrier air stream and is sucked and discharged through the dust exhaust plenum 13 into the piping 16 outside the machine. Furthermore, the dust riding on the carrier airflow enters the dust separation and recovery device 14, where it is separated from the carrier airflow,
Only the airflow is exhausted to the downstream side of the electrostatic precipitator main body 2 through the suction fan 15, for example. On the other hand, the dust separated and collected from the conveying air stream in the dust separation and recovery device 14 is appropriately repacked into a bag or the like and then transported to a processing plant where it is disposed of. In addition, in a configuration in which multiple sets of dust collection units are housed in an electrostatic precipitator as shown in the figure, and the air blow nozzles 10 are arranged in multiple stages above and below in opposition to these dust collection units, all the nozzles are simultaneously disposed of. Air blowing increases the capacity of the compressor 11 and suction fan 15, which increases equipment costs, so as a countermeasure, the air blow nozzle 10 is connected in parallel to the piping 12 via the nozzle valve 20 at each stage, and the electric collector A method is adopted in which a plurality of dust collection units housed in the dust machine main body 2 are divided into blocks and the operation cycle of dust removal and collection is repeated. With the dust dust removal and collection method described above, the dust collected within the electrostatic precipitator main body 2 can be smoothly discharged outside the machine and separated and collected without being scattered again outside the machine.

On the other hand, the high potential side electrodes constituting the charging unit 8 and dust collection unit 9 in the electrostatic precipitator main body 2 are supported via insulators, but during dust collection operation, the electrostatic precipitator A portion of the gas to be treated that flows into the casing of the main body 2 flows around the insulator, and if this continues, suspended particles in the gas to be treated may adhere to the surface of the insulator, reducing the dielectric strength of the insulator. From the above point of view, as a means to prevent floating particles from adhering to the insulator surface and maintain insulation performance, the insulator that supports the high potential electrode is housed in an insulator housing chamber, and this insulator housing chamber is insulated from the outside as a purge source. BACKGROUND ART An air purge system is conventionally known that prevents floating particles from entering a room from the outside by supplying a pressurized gas and blowing out a purge source from a gap in the room to the outside. In particular, in the method described above, in which the dust collected in the dust collection unit is removed by air blowing, the dust flies into the casing and creates a highly concentrated dust atmosphere, so this air purge method is extremely difficult to use. This is considered an effective method.

By the way, according to the test results of actually installing an electrostatic precipitator using the air purge method described above in a tunnel and running the machine using purified air from inside the tunnel as a purge source, it was found that air purge caused the insulators to enter the insulator chamber. Despite efforts to prevent the intrusion of floating particles, the insulator's insulation performance deteriorated and leakage current increased over a relatively short period of time. After considering this point, it was found that the cause lies in the following points. In other words, the atmosphere inside the tunnel is relatively humid, so when the air inside the tunnel is directly used as a purge source and this air is pressurized and supplied to the insulator chamber through a compressor, the Hage source must first pass through the compressor. During the process, it is heated and becomes a low humidity state, but as it passes through the pipes from the compressor to the electrostatic precipitator, the ambient temperature is low, so the temperature of the purge source decreases, and the relative humidity of the purge source increases again. . As a result, the purge source blown into the insulator chamber touches the insulator and condenses on its surface, reducing the creeping dielectric strength of the insulator.

[Objective of the Invention] The object of the present invention has been made in view of the above-mentioned problems, and is to provide an electric collector that can maintain stable dielectric strength of an insulator even when installed and operated in a tunnel. The purpose of this company is to provide dust equipment.

[Summary of the Invention] In order to achieve the above object, the present invention provides an insulator storage chamber containing an insulator that supports a high voltage side electrode in a dust collector main body, a dust separating means, and a dust collector main body. A switching means is provided between the discharge part and the dust separation means, and switches the inlet part of the dust separation means to communicate with the dust discharge part or open to the outside air, a dehumidification means, and a suction side thereof. A suction blower means is connected to the outlet side of the dust separation means, and the blower side thereof is connected to the insulator storage chamber via the dehumidification means.

[Embodiment of the Invention] FIG. 4 is a schematic diagram showing an embodiment of the invention, and the same parts as in FIG. 1 are designated by the same reference numerals. In FIG. 4, the dust collection unit 9 is arranged between the left and right end plates 23 by alternately arranging the ground side dust collection electrode 21 and the high potential side dust collection electrode 22, of which the high potential side dust collection electrode 22 is the electrode The electrode support rod 24 is installed on a support rod 24, and the electrode support rod 24 penetrates holes in the left and right end plates 23, projects outward, and is insulated and supported by an insulator 25. On the other hand, each insulator 25 has a side plate 23
The electrode support rod 24 is housed in an insulator storage chamber 26 attached to the electrode support rod 24, and a support rod for supporting the electrode support rod 24 protrudes through an opening 26a of the insulator storage chamber 26.

Each insulator storage chamber 26 is connected to one end of the pipe 27A. The other end of the pipe 27A is connected to the outlet end of the dehumidifier 28. One end of the pipe 27B is connected to a blowing end of a suction fan 15 as a suction blowing means, and the other end is connected to an inlet end of a dehumidifier 28.

One end of the pipe 16A is connected to the dust discharge plenum 13 (not shown; see FIG. 1) of the electrostatic precipitator main body 2, and the other end is connected to the inlet end of the dust separation and recovery device 14. One end of the pipe 16B is connected to the outlet end of the dust separation and recovery device 14, and the other end is connected to the suction fan 1.
Connect to the suction end of No.5.

A first on-off valve 29 is provided in the middle of the pipe 16A. Furthermore, a second opening/closing valve 30 is provided in the middle of the pipe 16A between the first opening/closing 29 and the dust separation and recovery device 14, and a branch with one end open to the atmosphere surrounding the dust separation and recovery device 14. Connect the other end of the tube 31. The first on-off valve 29 and the second on-off valve 30 are controlled by a control device (not shown) as described later.

With the above configuration, first, during dust collection operation, the first on-off valve 29 is closed, the second on-off valve 30 is opened, and the suction fan 15 is operated. As a result, the ambient air around the dust separation and recovery device 14 is sucked into the dust separation and recovery device 14 through the second on-off valve 30, the branch pipe 31, and the pipe 16A, where the dust is separated and becomes clean air. The clean air thus obtained is transferred to the pipe 16B, the suction fan 5, and the pipe 27.
The air is sent through B to the dehumidifier 28, where it is dehumidified to become dry air, which is further pressurized and supplied into the insulator storage chamber 26 through the pipe 27A, and is blown out from the opening 26a of the insulator storage chamber 26 to the outside.

On the other hand, when cleaning the collection duct,
The on-off valve 29 is opened, the second on-off valve 30 is closed, and the suction fan 15 is operated. As a result, the pipe 1 is removed from the dust discharge plenum 13 of the electrostatic precipitator main body 2.
6A and the first on-off valve 29, the air containing dust that has been brushed off from the electrodes in the electrostatic precipitator main body 2 is sucked into the dust separation and recovery device 14, where the dust is separated and becomes clean air. . The clean air thus obtained is dehumidified in the same manner as described above and is supplied under pressure into the insulator storage chamber 26.

In this way, during dust collection operation, suspended particles in the gas to be treated flowing inside the casing of the electrostatic precipitator main body 2 and dust filling the casing due to air blowing during dust removal are removed from the insulator storage chamber 2.
6 is effectively prevented. Moreover, since dry air is supplied to the insulator storage chamber 26, it is possible to effectively prevent the dielectric strength of the insulator 25 from decreasing. Note that the supply pressure of the purge source is set to a higher pressure than the internal pressure of the casing when dust is removed by air blowing.

[Effects of the Invention] As described above, according to the present invention, the insulator supporting the high potential electrode of the electrostatic precipitator is housed in the insulator housing chamber, and clean and dry air is supplied thereto. Therefore, it is possible to effectively prevent floating particles from entering the insulator storage chamber during dust collection operation and when the collected dust is removed by air blowing, and to effectively prevent deterioration of the dielectric strength of the insulator.
In this way, it is possible to provide a highly reliable electrostatic precipitator that can be applied, for example, to cleaning ventilation equipment for contaminated air in road tunnels. Further, according to the present invention,
The dust separation means used to blow off the collected dust is effectively used to purify the gas supplied into the insulator storage chamber. Electrostatic precipitators can be provided at a much lower cost than if they were supplied.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a conventional electrostatic precipitator, and FIGS. 2 and 3 are operation explanatory diagrams of the electrostatic precipitator in the dust collection operation and dust collection state in FIG. 1, respectively. FIG. 4 is a schematic diagram showing an embodiment of the present invention. 2...Electrostatic precipitator body, 3...Blower, 7...
...High voltage power supply device, 8...Charging unit, 9...Dust collection unit, 10...Air blow nozzle, 1
2, 16, 16A, 16B, 27A, 27B...
Piping, 14... Dust separation and recovery device, 15... Suction fan, 22... High potential side electrode, 25... Insulator,
26...Insulator storage room, 28...Dehumidifier, 29...
First on-off valve, 30... Second on-off valve, 31... Branch pipe, A, A'... Gas flow to be treated, B... Dust conveying air flow.

Claims (1)

[Scope of Claims] 1. An insulator storage chamber containing an insulator that supports a high-voltage side electrode in the dust collector main body, a dust separation means, and a dust discharge part of the dust collector main body and the dust separation means. a switching means provided between the inlet of the dust separation means to communicate with the dust discharge section or open to the outside air; a dehumidification means; and a dehumidification means, the suction side of which is connected to the outlet of the dust separation means 1. An electrostatic precipitator comprising: a suction blower means connected to the side of the insulator storage chamber, and a suction blower means connected to the insulator housing chamber through the dehumidification means.