JPH0418945A - Electrostatic precipitator - Google Patents

Abstract

PURPOSE:To restrain the amount of ozone generation and to facilitate the maintenance, such as the washing of electrode, by constituting a discharge electrode of the plate body whose end surface confronting a counter electrode is formed in a curved surface. CONSTITUTION:Corona discharge is generated between the counter electrode 5 and the discharge electrodes 1 confronting it with required distance and the dust in the air is charged by this corona discharge to be collected. The discharge electrode 1 is constituted of the plate body whose end surface 1a confronting to the counter electrode 5 is formed in a curved surface. As a result, the amount of ozone generation is restrained to the utmost, and the stability in lapse of time having excellent electro-discharge property is obtained. And, the handling in construction, transportation, and maintenance, such as the washing of electrode, are facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an electrostatic precipitator, and particularly to improvements in the electrode portion thereof.

(Prior art) An electric precipitator has two main functions: a charging function that generates corona discharge between a discharge electrode and a counter electrode, and charges dust in the air with the corona discharge; It has two functions: a dust collection function to collect dust. Among these, the discharge electrode of the charging section is made of a needle-like electrode, a thin metal wire stretched by a spring body, or the like, in order to improve the discharge performance. Among these picture electrodes, the needle-like electrode produces concentrated discharge (7
However, there are problems with the high ozone generation, deterioration due to wear, evaporation, etc., resulting in poor quality. For this reason, the mainstream electric precipitators for household use are those of the wire type using a thin metal wire stretched by a spring body or the like as the discharge Y5 electrode.

FIG. 9 shows a charging section in a conventional electrostatic precipitator using such a wire method.

An electrostatic precipitator is provided with a charging section on the upstream side of the flow of air to be purified, and a dust collecting section (not shown) on the downstream side. The charging section includes a discharge electrode 11 and a counter electrode 12 made of fine metal wires such as tungsten wire. The thin metal wire of the discharge electrode 11 has an extremely thin wire diameter and is tensioned by a spring body or the like in order to obtain high discharge performance. In this example, a (+) high voltage is applied to the discharge electrode 11 to generate a corrode discharge, and dust in the air is charged. On the other hand, the dust collection section (not shown) is composed of, for example, a dust collection electrode and a counter electrode that are arranged to face each other with an appropriate interval. A voltage lower than the high voltage applied to the discharge electrode 11 is applied between the two electrodes, so that dust charged in the charging section is collected.

As mentioned above, an electric precipitator collects dust in the air, so each electrode in the charging part and dust collecting part should be cleaned at appropriate intervals of use to restore dust collection efficiency. is needed.

(Problems to be Solved by the Invention) Conventional electrostatic precipitators use a wire system that uses a thin metal wire stretched by a spring body, etc. as a discharge electrode in order to improve discharge performance and minimize the amount of ozone generated. Those are the mainstream.

However, the wire type electrostatic precipitator has the following problems because it uses a thin metal wire with an extremely small diameter stretched by a spring body or the like as a discharge electrode. That is, (1) there is a risk that the fine metal wire may be cut during manufacturing, transportation, maintenance such as electrode cleaning, etc., and great care must be taken in handling. ■In order to maintain a constant distance between the thin metal wire, which is the discharge electrode, and the counter electrode, a constant tension must be applied to the thin metal wire at all times. As a result, there is a risk that the thin metal wire may break due to long-term use, and if breakage occurs, there is a risk that an accident may occur due to contact with the counter electrode. ■Even during manufacturing, it was necessary to manage the tension of the thin metal wire, leading to high manufacturing costs. ■In order to prevent accidents due to contact with the electrode part from the outside, it is necessary to install an insulator guard to prevent the thin metal wire from being exposed in the opening, but since the thin metal wire and the insulator guard cannot be integrated,
It was configured as a separate part. For this reason, the charging portion had to be thicker to some extent.

In addition, as an improved version of the wire-type electrostatic precipitator, which has the above-mentioned problems, a plate-type electric precipitator using a thin metal plate as the discharge electrode, with its end face facing the counter electrode, has been considered. There is. However, with plate-type products that use thin metal plates, it is difficult to obtain end faces with a stable surface condition during manufacturing, and after long-term use, the machining and solid parts where electric charges are concentrated gradually change due to evaporation, etc. Since moxibustion changes over time in the discharge characteristics, further improvements have been required.

Therefore, one object of the present invention is to provide an electrostatic precipitator that has stable discharge characteristics over time, can suppress the amount of ozone generated as much as possible, and is easy to maintain such as electrode cleaning.

[Structure of the Invention (Means for Solving the Problems) In order to solve the above problems, the present invention provides a method for causing corona discharge between a discharge electrode and a counter electrode that face each other at a required interval, This electric precipitator charges and collects dust in the air using this corona discharge, and the discharge electrode is constituted by a plate-shaped body whose end face facing the counter electrode is formed into a curved surface. A basic summary.

Moreover, in order to better achieve the object 1-, it is preferable that the present invention has the following second to seventh configurations.

That is, secondly, in the above basic configuration, the opposite electrode is
The discharge electrode is configured to be located on the same plane as the discharge electrode, which is made up of a plate-shaped body with an end face formed into a curved surface.

Thirdly, in the basic configuration, the plate-shaped body serving as the discharge electrode is constructed by cutting or polishing the cut end surface of a conductive thin plate to form a curved surface.

Fourthly, in the basic configuration, the plate-like body serving as the discharge electrode is constructed by forming a cut end surface of a conductive thin plate into a curved surface by etching, melting, or evaporation.

Fifth, in the basic configuration, the plate-like body serving as the discharge electrode is formed by bending a conductive thin plate or compressing a conductive tube or wire so that the end surface becomes a curved surface.

Sixthly, in the basic configuration, the plate-shaped body serving as the discharge electrode is constructed by forming a conductive paste into a curved surface by dipping, printing, or coating on the end surface of an insulating sheet.

Seventh, in the basic configuration, the plate-like body serving as the discharge electrode is constructed by forming a conductive layer on the end face of an insulating sheet by plating, thermal spraying, or evaporation so as to have a curved surface.

(Function) With the above configuration, there is no edge portion where charges are concentrated on the end face of the discharge electrode facing the counter electrode, and stable discharge characteristics are obtained, and its change over time and the amount of ozone generation can be suppressed as much as possible. Furthermore, since there is almost no risk of the discharge electrodes being cut, maintenance such as cleaning the electrodes becomes unnecessary.

(Example) Embodiments of the present invention will be described below based on the drawings.

1 and 2 are diagrams showing a first embodiment of the present invention. FIG. 2(B) is an enlarged view of the circled portion in FIG. 2(A).

First, to explain the structure of an electrostatic precipitator, a charging section equipped with a discharge electrode 1 and a counter electrode 5 is provided on the upstream side of the flow of air to be purified, and a charging section equipped with a discharge electrode 1 and a counter electrode 5 is provided downstream (+111 0. And in this example,
The emission mW pole 1 is configured as follows.

That is, the discharge electrode 1 is made of SUS foil with a thickness of approximately 20 μml, and the end surface that becomes the discharge portion facing the counter electrode 5 has a curved surface 1a.
is formed. The curved end surface 1a is formed by polishing the cut end surface of SUS foil. Discharge electrode 1
is covered with an insulating sheet 7 on both sides, and is installed so that the plate surface is perpendicular to the air flow direction.

On the other hand, the counter electrode 5 is formed of a SUS plate with a thickness of approximately 5 mm, and is installed parallel to the air flow direction. The end surface of the discharge electrode 1 formed on the curved surface 1a is opposed to the plate surface of the counter electrode 5 with a required spacing therebetween.

Since the electrostatic precipitator of this embodiment is constructed as described above, a high voltage is applied between the discharge electrode 1 as the positive electrode and the counter electrode 5 as the negative electrode, to generate a corona discharge. In this case, since there are no edges where charges are concentrated on the end face of the discharge electrode 1 formed on the curved surface 1a, stable discharge characteristics are obtained and the amount of ozone generation is suppressed as much as possible, and at the same time, the discharge characteristics are stabilized over time. You can get sex. Furthermore, when applying such a high voltage, f! Since the plate surface of the S electrode 1 is covered with an insulating sheet 7, accidents caused by contact from the outside are prevented. Furthermore, the discharge electrode 1 is free from the risk of cutting accidents as with thin metal wires. Therefore, there is no danger of cutting during manufacturing, transportation, maintenance (cleaning, etc.), long-term use, etc., and handling becomes easier.

In this embodiment, the curved surface of the end surface of the discharge electrode 1 ]a
was formed by polishing the cut end surface of the SUS sheet, but it may also be formed by other mechanical means such as cutting.

Next, FIG. 3 shows a second embodiment of the present invention. FIG. 3(B) is an enlarged view of the circled portion in FIG. 3(A).

In addition, in the drawings showing each embodiment from FIG. 3 onward, the same or equivalent members and parts as in FIG. 1 and FIG. do.

In this embodiment, the discharge electrode 1 is constructed by etching the cut end surface of a SUS foil having a thickness of 20 t1m, so that the end surface serving as the discharge portion is formed into a curved surface 1b.

Stable discharge action such as stability over time, ease of handling, etc. are almost the same as those of the first embodiment.

In addition, in this embodiment, the curved surface 1b of the end surface portion of the discharge electrode 1
is formed by etching the cut end surface of SUS foil, or may be formed by other chemical or physical means such as melting or evaporation.

FIG. 4 shows a third embodiment of the invention. Figure 4 (B
) is an enlarged view of the circled part in FIG.

The discharge electrode 2 of this example is made by bending a 20 μm thick SUS foil, so that the end surface thereof has a curved surface 2a that becomes a discharge part.
is formed.

Stable discharge action such as stability over time, ease of handling, etc. are almost the same as those of the first embodiment.

In addition, in this embodiment, the curved surface 2a of the end surface portion of the discharge electrode 2
was formed by bending SUS foil, but it may also be formed by compression molding a conductive tube or wire.

5 and 6 show a fourth embodiment of the present invention.

In this embodiment, the discharge electrode 2 is made by bending a 20 μm thick SUS foil to form a curved surface 2a that becomes a discharge portion on the end surface, as in the third embodiment. There is.

On the other hand, the counter electrode 6 is formed of a 0.5 mm thick SUS plate. The discharge electrode 2 and the counter electrode 6 are attached to the same insulating sheet 8, so that the discharge electrode 2 and the counter electrode 6 are on the same surface, and the curved surface 2a of the discharge electrode 2 faces the counter electrode 6 with a space in between. It is set up to do so. Image electrode 2.6
are installed perpendicular to the air flow direction.

8a is an insulating sheet for covering the plate surface of the discharge electrode 2.

According to this embodiment, since the discharge electrode 2 and the counter electrode 6 are arranged on the same surface, the conventional charging section shown in FIG.
In this example, the thickness was 5 m.
It is possible to make the device extremely thin, on the order of 1.2 ft. m, and even if the installation space width is small, it can be installed in a large area, and as a result, it is possible to improve the dust collection ability. In addition, the stability of discharge characteristics over time, ease of handling, etc. are almost the same as those of the first embodiment.

In this fourth embodiment, the discharge electrode 2 and the counter electrode 6 may have a shape other than the comb shape shown in FIG. 5, as long as they are placed at opposing positions with a space between them.

7 and 8 show a fifth embodiment of the present invention.

FIG. 8(B) is an enlarged view of the circled portion in FIG. 8(A).

In this embodiment, the main body of the emitting rfs electrode is formed of an insulating sheet 3 made of a polyethylene terephthalate sheet with a thickness of 20 μm, and the curved surface that becomes the discharge portion is coated with a carbon-based conductive paint by dipping and heat-treated on the end surface of the insulating sheet 3. 4 is formed.

Stable discharge action such as stability over time, handling properties, etc. are almost the same as those of the first embodiment.

In addition, in this fifth embodiment, a curved surface 4 that will become a discharge portion is formed on the end surface of an insulating sheet 3 made of polyethylene prephthalate by applying carbon-based conductive paint by dipping and heat treatment, or as an insulating sheet. It is possible to form a discharge portion having a curved surface similar to that described above even by using a ceramic substrate such as alumina or silicon carbide and gold or the like as a conductive paste and firing at a high temperature. Furthermore, although the conductive paint was formed by dipping coating and heat treatment, it is possible to obtain the same effect and effect as above if a thin conductive curved surface is formed on the end surface of the insulating sheet using a forming method such as plating, thermal spraying, or evaporation. is iiJ Noh. In addition, in this example, in order to promote charge concentration and increase discharge efficiency, only the exposed discharge portion of the end face was configured to form a curved surface with a conductive material, but a conductive layer was formed on the entire insulating sheet, It may be configured to cause discharge at the end face.

In each of the embodiments described above, if only the curved surfaces 1a, 2a, and 4 of the discharge portion of the discharge electrode are made thin, the main body can be made of a thicker electrode material or insulating sheet. Further, as the electrode material, other metal materials other than SU3 or the like may be used as long as they are less likely to deteriorate due to discharge and generated ozone. Furthermore, the discharge electrode, etc. may be supported by insulating sheets 7 and 8; however, other support structures may be used as long as a space of a certain distance can be maintained between the discharge electrode and the counter electrode. can. Also, when corona discharge occurs, whether the discharge electrode side is the positive electrode or vice versa,
The group ff1m electrode side may be used as a negative electrode.

[Effects of the Invention] As explained above, according to the present invention, the discharge electrode is
Since it is composed of a plate-like body with a curved end face facing the counter electrode, there is no edge where charge is concentrated on the end face of the radiation f[ti pole facing the counter electrode, and stable discharge characteristics can be obtained. In addition to being able to suppress the amount of ozone generated as much as possible,
Excellent discharge characteristics and stability over time can be obtained. Furthermore, since there is almost no risk of the discharge electrode being cut, it is easier to handle during manufacturing, transportation, maintenance such as electrode cleaning, etc.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a charging section in a first embodiment of an electrostatic precipitator according to the present invention, FIG. 2 is an enlarged sectional view of the circled part in FIG. 1, and FIG. FIG. 4 is an enlarged sectional view similar to FIG. 2 showing a charging section in the third embodiment of the present invention; FIG. 5 is an enlarged sectional view similar to FIG. 2 showing a charging section in a third embodiment of the invention; FIG. 6 is an enlarged sectional view of the circled portion in FIG. 5; FIG. 7 is a perspective view showing the charging portion in the fifth embodiment of the present invention; FIG. 8 7 is an enlarged sectional view of the circled portion in FIG. 7, and FIG. 9 is a configuration diagram showing a charging section in a conventional electrostatic precipitator. 1.2: discharge electrode, 1a, 2a, 4: curved surface of the end surface of the discharge electrode, 3: insulating sheet forming the main body of the discharge electrode, 5.6: counter electrode.

Claims (1)

[Claims] An electrostatic precipitator that generates corona discharge between a discharge electrode and a counter electrode that face each other at a required interval, and charges and collects dust in the air with this corona discharge. . An electrostatic precipitator, characterized in that the discharge electrode is constituted by a plate-shaped body whose end face facing the counter electrode is formed into a curved surface.