Electric dust collector

Abstract

To generate stable discharge between a discharge electrode for generating ions by corona discharge and a collecting electrode, when the discharge electrode and a grounding electrode, a high-voltage electrode and the collecting electrode for collecting floating fine particles charged by the corona discharge are arranged on approximately the same plane.SOLUTION: An electric dust collector includes a discharge electrode to which a high voltage for generating ions by corona discharge is applied, a grounding electrode kept at a grounding potential, and a high-voltage electrode and a collecting electrode for collecting floating fine particles in a treatment air flow charged by the corona discharge by Coulomb force, wherein the discharge electrode, the grounding electrode, the high-voltage electrode and the collecting electrode are installed on approximately the same plane in a direction approximately parallel to the treatment air flow, and the high-voltage electrode and the collecting electrode have such structures that a conductive member is surface-treated with a non-conductive member.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an electrostatic precipitator. [Background technology]

[0002] Patent Document 1 describes a dust collection unit that integrates an airtight ionizer section consisting of an ionization electrode and an ionization electrode plate, and a dust collection electrode that collects charged dust particles ionized by the ionizer section, and that is arranged approximately on a plane perpendicular to the direction of air flow. Patent Document 2 describes an electrostatic precipitator that includes an ionization section that generates a corona discharge between a discharge electrode and a counter electrode to charge dust in the air, and a collector section that collects the dust charged in the ionization section using a high-voltage electrode and a dust collecting electrode.The counter electrode of the ionization section and the dust collecting electrode of the collector section are integrated together, and a plurality of shared electrodes that are parallel to the airflow are arranged in a direction perpendicular to the airflow.The high-voltage electrodes of the collector section are arranged between these shared electrodes, and the discharge electrodes of the ionization section are provided at the upstream ends of these high-voltage electrodes so as to face the shared electrodes.The cross-sectional shape of the high-voltage electrode of the collector section is trapezoidal, and the gap between the high-voltage electrode and the dust collecting electrode is gradually narrowed along the airflow. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3132116 [Patent Document 2] Patent No. 3700455 Summary of the Invention [Problem to be solved by the invention]

[0004] It is conceivable to reduce the thickness of an electrostatic precipitator by arranging the discharge electrode and ground electrode that generate ions by corona discharge, and the high-voltage electrode and collecting electrode that collect airborne particulates charged by corona discharge, on approximately the same plane. In this case, if a configuration is adopted in which the collecting electrode is made of a conductive material, spark discharge will occur between the discharge electrode and the collecting electrode if a sufficient insulation distance is not ensured for the voltage applied to the discharge electrode and the collecting electrode, making it impossible to generate a stable discharge.

[0005] The object of the present invention is to generate a stable discharge between a discharge electrode and a ground electrode that generate ions by corona discharge, and a high-voltage electrode and a collecting electrode that collect airborne particles charged by corona discharge, when these electrodes are arranged on approximately the same plane. [Means for solving the problem]

[0006] With this objective in mind, the present invention provides an electrostatic precipitator comprising a discharge electrode to which a high voltage is applied to generate ions by corona discharge, a ground electrode maintained at ground potential, and a high-voltage electrode and a collecting electrode that use Coulomb force to collect suspended fine particles in the treatment airflow that have been charged by corona discharge, wherein the discharge electrode, ground electrode, high-voltage electrode, and collecting electrode are installed on approximately the same plane and in a direction approximately parallel to the treatment airflow, and the high-voltage electrode and collecting electrode have a structure in which a conductive member is surface-treated with a non-conductive member.

[0007] The electrostatic precipitator may include a plurality of charging electrodes, each consisting of at least one discharge electrode and at least one ground electrode, arranged at a predetermined interval, and wherein two adjacent charging electrodes among the plurality of charging electrodes are either a discharge electrode and a ground electrode, or two ground electrodes. In this case, the electrostatic precipitator may include at least one high-voltage electrode and at least one collecting electrode arranged at a distance narrower than the predetermined distance in at least one of the plurality of areas separated by the plurality of charging electrodes, such that the high-voltage electrode is not adjacent to the discharge electrode. In this case, the at least one area may not include the area between the discharge electrode and one ground electrode adjacent to the discharge electrode, nor the area between the discharge electrode and another ground electrode adjacent to the discharge electrode. The space between any two adjacent electrodes of the discharge electrode, the ground electrode, the high-voltage electrode, and the collecting electrode may be configured to allow the process airflow to pass through. The ground electrode may be formed of a plate-shaped or rod-shaped conductive member. The discharge electrode may be formed of a needle-shaped or sawtooth-shaped conductive member, or a plurality of fibrous conductors. The electrostatic precipitator may further include a high-voltage power supply that applies a common high voltage between the discharge electrode and the ground electrode, and between the high-voltage electrode and the collecting electrode. [Effects of the Invention]

[0008] According to the present invention, when a discharge electrode and a ground electrode that generate ions by corona discharge and a high-voltage electrode and a collecting electrode that collect airborne particles charged by corona discharge are arranged on approximately the same plane, a stable discharge can be generated between the discharge electrode and the collecting electrode. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view showing an example of the overall configuration of an air purification unit according to an embodiment of the present invention. [Figure 2] 1 is a diagram showing a first configuration example of an integrated electric dust collector according to the present embodiment. [Figure 3] 3 is a diagram showing an example of the configuration of a collecting electrode and a high-voltage electrode of the integrated electric dust collector according to the present embodiment. FIG. [Figure 4] FIG. 3 is a diagram showing a second configuration example of the integrated electric dust collector according to the present embodiment. [Figure 5A] FIG. 1 is a diagram showing the operation of the two-stage electric dust collector of Comparative Example 1. [Figure 5B] 5A and 5B are diagrams illustrating the operation of the integrated electric dust collector according to the present embodiment. [Figure 6] FIG. 10 is a diagram showing the performance when the integrated electric dust collector of the present embodiment is mounted on an air purifier. [Figure 7] 10 is a diagram illustrating the necessity of forming the collecting electrode of the integrated electrostatic precipitator in this embodiment by surface-treating a conductive member with a non-conductive member. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0011] [Background and Overview of the Present Embodiment] Electrostatic precipitators (EPs) are an environmentally friendly dust collection technology that eliminates the need for disposal or replacement and charges airborne particles by electrostatically charging them through discharges. While charging airborne particles involves discharges, creating an uneven electric field, collecting charged airborne particles in the charging region does not involve discharges and creates an even electric field. There are two common configurations of electrostatic precipitators. One is a single-stage electrostatic precipitator, which uses only an uneven electric field, in which the ground electrode facing the discharge electrode of the charging section also serves as a dust collection electrode. The other is a two-stage electrostatic precipitator, which uses both an even and an uneven electric field, and consists of a charging section that charges airborne particles through discharges and a collecting section that captures the charged airborne particles through Coulomb force. The airborne particles targeted for indoor air quality purification are called PM2.5. Because it is difficult to improve the collection efficiency of fine airborne particles with a single-stage electrostatic precipitator, two-stage electrostatic precipitators are often used. However, in a two-stage electrostatic precipitator, the charging section and the dust collecting section must be arranged as separate units, which places a limit on how thin the device can be. Therefore, in this embodiment, we provide an integrated, thin electrostatic precipitator that combines a mechanism for charging airborne particles by discharge and a mechanism for collecting dust, and in which both an uneven electric field and a uniform electric field coexist, within the limited space of an air purifier or air conditioner.

[0012] Here, "integration" does not only mean that the structure is integrated, but also that both a non-uniform electric field and a uniform electric field exist within the structure. In other words, a structure in which only a non-uniform electric field exists is a single-stage electrostatic precipitator, while a structure in which the non-uniform electric field and the uniform electric field are separated is a two-stage electrostatic precipitator. Integrating the charging region and the dust collection region makes it possible to slim down the electrostatic precipitator and reduce costs.

[0013] [Configuration of the air purification unit in this embodiment] FIG. 1 is a perspective view showing an example of the overall configuration of an air purification unit 1 according to the present embodiment. As shown in the figure, the air purification unit 1 includes an electrostatic precipitator 10, a fan 40, a housing 50 that houses these components, and a high-voltage power supply 60 that supplies high voltage to the electrostatic precipitator 10. Here, the housing 50 is shown by a dashed line so that the configuration of the electrostatic precipitator 10 provided inside the housing 50 can be seen. The electrostatic precipitator 10 may be configured in the form of a detachable unit. Here, the direction (ventilation direction) of the treatment airflow (ventilation) is set in the direction indicated by the arrow. The ventilation is performed by a fan 40 provided downstream (downwind side) of the electrostatic precipitator 10 in the ventilation direction.

[0014] The electrostatic precipitator 10 integrates a charging region where airborne particles are charged and a collection region where the charged airborne particles are collected. Therefore, the electrostatic precipitator 10 includes multiple charging electrodes 11 and multiple collection electrodes 12. The multiple charging electrodes 11 include at least one ground electrode 11A and at least one discharge electrode 11B, and the multiple collection electrodes 12 include at least one collecting electrode 12a and at least one high-voltage electrode 12b. The ground electrode 11A, discharge electrode 11B, collecting electrode 12a, and high-voltage electrode 12b will be described in detail later. Hereinafter, the ground electrode 11A, discharge electrode 11B, collecting electrode 12a, and high-voltage electrode 12b may also be referred to as ground electrode A, discharge electrode B, collecting electrode a, and high-voltage electrode b, respectively.

[0015] The housing 50 has an inlet section 51 provided on the upstream side (upwind side) of the ventilation direction, and an outlet section 52 provided on the downstream side (downwind side) of the ventilation direction. The inlet section 51 may be provided with a mesh (net, lattice) or the like. The mesh (net, lattice) or the like provided in the inlet section 51 is preferably provided so as to reduce resistance to ventilation while preventing the user from coming into contact with the electrostatic precipitator 10. The inlet section 51 may also be provided with a pre-filter that prevents large particles from entering. The housing 50 is made of a resin material such as ABS (acrylonitrile butadiene styrene copolymer).

[0016] The fan 40 is provided at an outlet section 52 on the downwind side of the housing 50. The air flow (ventilation) enters the housing 50 from an inlet section 51, passes through the electrostatic precipitator 10, and exits the housing 50 from an outlet section 52 where the fan 40 is provided. The air purification unit 1 may be placed in any orientation as long as ventilation is not obstructed.

[0017] The high-voltage power supply 60 applies a high direct current (DC) voltage between the ground electrode 11A and the discharge electrode 11B, thereby generating a corona discharge (electric discharge) between the ground electrode 11A and the discharge electrode 11B. Then, ions generated by the generated corona discharge adhere to the airborne particles, thereby charging the airborne particles. The high-voltage power supply 60 also applies a high direct current (DC) voltage between the collecting electrode 12a and the high-voltage electrode 12b. As a result, the airborne particles charged by the corona discharge adhere to the surface of the collecting electrode 12a due to electrostatic force (Coulomb force). As a result, the airborne particles are collected. That is, the high voltage power supply 60 can apply a common high voltage between the ground electrode 11A and the discharge electrode 11B, and between the collection electrode 12a and the high voltage electrode 12b, although this is not necessarily limited to this. Although the high-voltage power supply 60 is not included in the electrostatic precipitator 10 here, it may be included in the electrostatic precipitator 10.

[0018] Fig. 2 is a diagram showing a first configuration example of the electrostatic precipitator 10 of Fig. 1. Fig. 2 shows a cross-sectional view of the electrostatic precipitator 10 of Fig. 1 as seen from viewpoint V. Therefore, in Fig. 2, the ventilation direction is set to be from top to bottom as indicated by the arrow. As shown in the figure, the first configuration example of the electrostatic precipitator 10 includes a ground electrode A and a discharge electrode B as charging electrodes, and a collection electrode a and a high-voltage electrode b as dust collection electrodes.

[0019] The ground electrode A is an electrode for defining a ground potential in the charged area. The ground electrode A may be formed of a flat or rod-shaped conductive member. The ground electrode A is an example of a ground electrode that is maintained at a ground potential.

[0020] Discharge electrode B is an electrode that generates ions by corona discharge in order to charge suspended particles in the air. A high voltage is applied to discharge electrode B for this purpose. Discharge electrode B may be formed of a needle-shaped or sawtooth-shaped conductive member or a plurality of fibrous conductors. Discharge electrode B is an example of a discharge electrode to which a high voltage is applied to generate ions by corona discharge.

[0021] The collecting electrode a and the high-voltage electrode b are electrodes for collecting charged airborne particles by Coulomb force. As shown in FIG. 3, the collecting electrode a and the high-voltage electrode b may have a structure in which a conductive member 121 is surface-treated with a non-conductive member 122. Strictly speaking, however, the collecting electrode a and the high-voltage electrode b have a structure in which the conductive member 121 is exposed at the end, and a voltage can be applied to the high-voltage electrode b side, and the collecting electrode a side can be grounded. Here, metal or carbon is preferably used as the conductive member 121, and a resin film such as polyethylene terephthalate (PET) or an inorganic material film is preferably used as the non-conductive member 122. Furthermore, coating or lamination is preferably performed as the surface treatment. The collecting electrode a and the high-voltage electrode b are examples of high-voltage electrodes and collecting electrodes that use Coulomb force to collect airborne particles in the treatment airflow that have been charged by corona discharge.

[0022] In the first configuration example of the electrostatic precipitator 10, the ground electrode A, the discharge electrode B, the collecting electrode a, and the high-voltage electrode b are arranged on approximately the same plane and in a direction approximately parallel to the airflow to be treated. In this way, the first configuration example of the electrostatic precipitator 10 has a structure in which the charging region and the dust collection region are integrated and merged, and the electrodes are arranged on the same plane, which makes it possible to reduce the thickness of the air purification unit 1. Furthermore, in the first configuration example of the electrostatic precipitator 10, the spaces between any two adjacent electrodes of the ground electrode A, the discharge electrode B, the collecting electrode a, and the high-voltage electrode b are all configured to allow the airflow to pass through.

[0023] The arrangement order of the ground electrode A, discharge electrode B, collection electrode a, and high-voltage electrode b is not limited to that shown in Fig. 2. These electrodes may be arranged according to the following arrangement order rules.

[0024] The first rule is a rule for the arrangement order of a plurality of charging electrodes, each of which consists of at least one ground electrode A and at least one discharge electrode B. Specifically, the first rule is a rule that the plurality of charging electrodes are arranged at a predetermined interval, and that among the plurality of charging electrodes, any two adjacent charging electrodes are either a ground electrode A and a discharge electrode B, or two ground electrodes A.

[0025] According to the first rule, the ground electrode A and the discharge electrode B may be arranged, for example, as follows: "...-A-...-B-...-A-...-B-...-A-...".

[0026] Furthermore, the ground electrode A and the discharge electrode B do not necessarily have to be arranged in the order of ground electrode A, discharge electrode B, ground electrode A, discharge electrode B. In other words, according to the first rule, the ground electrode A and the discharge electrode B may be arranged, for example, as follows: "...-A-...-B-...-A-...-A-...-B-...-A-...".

[0027] On the other hand, the ground electrode A and the discharge electrode B are not arranged so that two adjacent charging electrodes become two discharge electrodes B. In other words, according to the first rule, the ground electrode A and the discharge electrode B are not arranged, for example, as "...-A-...-B-...-B-...-A-...".

[0028] In the above description of the arrangement order, the symbol "..." indicates an arbitrary arrangement of the collecting electrode a and the high-voltage electrode b.

[0029] The second rule is a rule for the arrangement order of the multiple charging electrodes and the multiple collection electrodes each consisting of at least one collecting electrode a and at least one high-voltage electrode b. Specifically, the second rule is a rule that in all of the multiple ranges separated by the multiple charging electrodes, at least one collecting electrode a and at least one high-voltage electrode b are arranged at intervals narrower than the predetermined interval, and the high-voltage electrode b is not adjacent to the discharge electrode B. Here, the range includes the range sandwiched between the two charging electrodes and the range outside the end charging electrodes.

[0030] According to the second rule, the ground electrode A, the discharge electrode B, the collecting electrode a, and the high-voltage electrode b may be arranged, for example, as follows: "...-AbabaBababAbabaBababA-..." Alternatively, the ground electrode A, the discharge electrode B, the collecting electrode a, and the high-voltage electrode b may be arranged, for example, as follows: "...-AbabaBababAbabAbabaBa-babA-...".

[0031] Furthermore, the ground electrode A, discharge electrode B, collecting electrode a, and high-voltage electrode b do not necessarily have to be arranged in the order of ground electrode A (collecting electrode a), discharge electrode B (high-voltage electrode b), ground electrode A (collecting electrode a), discharge electrode B (high-voltage electrode b). In other words, according to the second rule, the ground electrode A, discharge electrode B, collecting electrode a, and high-voltage electrode b may be arranged, for example, as follows: "...-AababaBababaAababaBab-abaA-...". Alternatively, the ground electrode A, discharge electrode B, collecting electrode a, and high-voltage electrode b may be arranged, for example, as follows: "...-AababaBababaAababaAab-abaBababaA-...".

[0032] On the other hand, the ground electrode A, the discharge electrode B, the collecting electrode a, and the high-voltage electrode b are not arranged so that two adjacent electrodes are a discharge electrode B and a high-voltage electrode b, or two high-voltage electrodes b. In other words, according to the second rule, the ground electrode A, the discharge electrode B, the collecting electrode a, and the high-voltage electrode b are not arranged, for example, as "...-AababBababAababBababA-...". Alternatively, the ground electrode A, the discharge electrode B, the collecting electrode a, and the high-voltage electrode b are not arranged, for example, as "...-AababBababAababAababB-ababA-...".

[0033] Fig. 4 is a diagram showing a second configuration example of the electrostatic precipitator 10 of Fig. 1. Fig. 4 shows a cross-sectional view of the electrostatic precipitator 10 of Fig. 1 as seen from viewpoint V. Therefore, in Fig. 4 as well, the ventilation direction is set to be from top to bottom, as indicated by the arrow. As shown in the figure, the second configuration example of the electrostatic precipitator 10 also includes a ground electrode A and a discharge electrode B as charging electrodes, and a collecting electrode a and a high-voltage electrode b as collecting electrodes. The ground electrode A, the discharge electrode B, the collecting electrode a, and the high-voltage electrode b are the same as those in the first configuration example, and therefore their explanation will be omitted.

[0034] Incidentally, in the second configuration example of the electrostatic precipitator 10, the ground electrode A, discharge electrode B, collecting electrode a, and high-voltage electrode b are also installed on approximately the same plane and oriented in a direction approximately parallel to the treatment airflow. However, in the second configuration example of the electrostatic precipitator 10, the collecting electrode a and high-voltage electrode b that were arranged between the ground electrode A and discharge electrode B in the first configuration example of the electrostatic precipitator 10 are removed, thereby expanding the discharge space of the charging region. Furthermore, in the second configuration example of the electrostatic precipitator 10, the spaces between any two adjacent electrodes of the ground electrode A, discharge electrode B, collecting electrode a, and high-voltage electrode b are all configured to allow the treatment airflow to pass through.

[0035] The arrangement order of the ground electrode A, discharge electrode B, collection electrode a, and high-voltage electrode b is not limited to that shown in Fig. 4. These electrodes may be arranged according to the following arrangement order rules.

[0036] This rule governs the arrangement order of multiple charging electrodes and multiple collection electrodes, each consisting of at least one collecting electrode a and at least one high-voltage electrode b. Specifically, this rule stipulates that, in at least one of multiple areas separated by the multiple charging electrodes, at least one high-voltage electrode and at least one collecting electrode are arranged at intervals narrower than a predetermined interval, such that the high-voltage electrode is not adjacent to a discharge electrode. Here, the "area" includes the area sandwiched between two charging electrodes and the area outside the end charging electrodes. In the second configuration example, in particular, the at least one area does not include the area between a discharge electrode and one ground electrode adjacent to the discharge electrode, nor the area between the discharge electrode and another ground electrode adjacent to the discharge electrode.

[0037] [Action of the electric dust collector in this embodiment] FIG. 5A is a diagram showing the operation of the two-stage electrostatic precipitator 6 of Comparative Example 1, and FIG. 5B is a diagram showing the operation of the integrated electrostatic precipitator 10 of this embodiment.

[0038] 5A, in the electrostatic precipitator 6 of Comparative Example 1, in the charging section 61, a discharge electrode B formed of, for example, a wire generates ions by corona discharge between the discharge electrode B and a ground electrode A, and the ions generate an electric field, charging the suspended particles P in the treatment airflow. Then, the charged suspended particles CP flow downstream in a linear flow indicated by arrow LF. In the dust collection section 62, a high voltage is applied between the collection electrode a and the high-voltage electrode b, and the charged particles CP are attracted in the electric field direction by Coulomb force and collected by the collection electrode a.

[0039] On the other hand, as shown in Fig. 5B, in the air purification unit 1 of this embodiment, in the electrostatic precipitator 10, the discharge electrode B generates ions by corona discharge between it and the ground electrode A, and the ions charge the suspended particles P in the treatment airflow through electric field charging and diffusion charging. Then, the charged suspended particles CP flow downstream in a fountain flow (a flow like a fountain) indicated by arrow FF. As a result, in the electrostatic precipitator 10, the collecting electrode a and the high-voltage electrode b collect the charged particles CP. In the air purification unit 1 of this embodiment, by utilizing diffusion charging in addition to electric field charging, the amount of charge increases and ions are spatially released. Therefore, even if the charging area is configured on the same plane as the dust collection area, it is possible to collect the suspended particulates P by fountain flow (a flow like a fountain).

[0040] [Performance of the electric dust collector in this embodiment] FIG. 6 is a diagram showing the performance of an air cleaner equipped with the electric dust collector 10 of this embodiment.

[0041] The configuration of the electrostatic precipitator 10 of Example 1 corresponds to the first configuration example described above. That is, Example 1 is an example in which an air purification unit 1 having an electrostatic precipitator 10 in which the charging area and the dust collection area are integrated and not structurally separated is mounted on an air purifier. The configuration of the electrostatic precipitator 10 of Example 2 corresponds to the second configuration example described above. That is, Example 2 is an example in which the charging area and the dust collection area are integrated, but the air purification unit 1 having the electrostatic precipitator 10 in which the charging area and the dust collection area are separated is mounted on an air purifier. On the other hand, Comparative Example 2 is an example in which an electric dust collector 70 is installed in an air purifier, in which a portion of the high-voltage electrode b in the dust collection area is exposed and serves as the discharge electrode B, thereby enabling integral molding.

[0042] As shown in the figure, there is little variation in the cleaning area between experiments in the air purifier equipped with the electrostatic precipitator 10 of Example 1 and the air purifier equipped with the electrostatic precipitator 10 of Example 2. This means that use of the electrostatic precipitator 10 of this embodiment can be said to stabilize discharge. On the other hand, the cleaning area varied greatly between experiments in the air purifier equipped with the electrostatic precipitator 70 of Comparative Example 2. This means that discharge would not be stable unless the electrostatic precipitator 10 of the present embodiment is used.

[0043] [Dust Collection Electrode of Electrostatic Precipitator in the Present Embodiment] FIG. 7 is a diagram showing the necessity of forming the collecting electrode a of the electric dust collector 10 in this embodiment by surface-treating a conductive member with a non-conductive member.

[0044] As shown in the figure, in the electrostatic precipitator 80 of Comparative Example 3, the collecting electrode a is formed of a conductive material. That is, the electrostatic precipitator 80 of Comparative Example 3 has a similar configuration to that in which a ground electrode A is provided instead of the collecting electrode a. In this case, a spark discharge occurs between the discharge electrode B and the ground electrode A, and therefore it is not possible to arrange multiple electrodes closely spaced as in the electrostatic precipitator 10 of the present embodiment and apply a high voltage similar to that of Example 1.

[0045] In contrast, a possible configuration for avoiding spark discharge while arranging multiple electrodes without changing the spacing between the electrodes is to set the height of the ground electrode A low, as in the electrostatic precipitator 90 of Comparative Example 4. However, with this configuration, some of the electrodes become short, which reduces the dust collection effect.

[0046] Therefore, in order to avoid spark discharge while arranging multiple electrodes without changing the spacing between the electrodes and without reducing the dust collection effect, the collecting electrode a is formed by surface-treating a conductive material with a non-conductive material, as in the electrostatic precipitator 10 of Example 1. Here, Example 1 corresponds to the first example configuration described above.

[0047] [Advantages of this embodiment] In this embodiment, a ground electrode 11A and a discharge electrode 11B are provided to form a non-uniform electric field in a part of the uniform electric field in the particulate collection area where the collecting electrodes 12a and the high-voltage electrodes 12b are alternately arranged, thereby forming a charged area and a particulate collection area on approximately the same plane. The collecting electrodes 12a and the high-voltage electrodes 12b are formed by surface-treating conductive members with non-conductive members. As a result, even if the collecting electrode 12a and the high-voltage electrode 12b are placed adjacent to the discharge electrode 11B, no spark discharge occurs, and a stable discharge can be generated via the ground electrode 11A, which has a defined ground potential. As a result, the collection area is no longer reduced. [Explanation of symbols]

[0048] 1...air purifying unit, 10...electrostatic precipitator, 11...charging electrode, 11A...grounding electrode, 11B...discharging electrode, 12...dust collecting electrode, 12a...collecting electrode, 12b...high voltage electrode, 40...fan, 50...casing, 60...high voltage power supply

Claims

1. a discharge electrode to which a high voltage is applied for generating ions by corona discharge; a ground electrode maintained at ground potential; a high-voltage electrode and a collecting electrode for collecting, by Coulomb force, suspended particles in the treatment airflow that have been charged by the corona discharge; Equipped with the discharge electrode, the ground electrode, the high-voltage electrode, and the collecting electrode are disposed on substantially the same plane and oriented in a direction substantially parallel to the treatment airflow, The high-voltage electrode and the collecting electrode have a structure in which a conductive material is surface-treated with a non-conductive material.

2. a plurality of charging electrodes, each consisting of at least one discharge electrode and at least one ground electrode, are arranged at predetermined intervals; 2. The electrostatic precipitator according to claim 1, wherein among the plurality of charging electrodes, two adjacent charging electrodes are the discharge electrode and the ground electrode, or two ground electrodes.

3. 3. The electric dust collector according to claim 2, wherein in at least one of the multiple ranges separated by the multiple charging electrodes, at least one of the high-voltage electrode and at least one of the collecting electrode are arranged at an interval narrower than the predetermined interval so that the high-voltage electrode is not adjacent to the discharge electrode.

4. 4. The electric dust collector according to claim 3, wherein the at least one range does not include a range between the discharge electrode and one of the ground electrodes adjacent to the discharge electrode, and a range between the discharge electrode and another of the ground electrodes adjacent to the discharge electrode.

5. 2. The electric dust collector according to claim 1, wherein the discharge electrode, the ground electrode, the high-voltage electrode, and the space between any two adjacent electrodes of the collecting electrode are configured to allow the treatment airflow to pass through.

6. 2. The electric dust collector according to claim 1, wherein the ground electrode is formed of a conductive member having a flat plate shape or a rod shape.

7. 2. The electrostatic precipitator according to claim 1, wherein the discharge electrode is formed of a needle-shaped or sawtooth-shaped conductive member or a plurality of fibrous conductors.

8. 2. The electrostatic precipitator according to claim 1, further comprising a high-voltage power supply that applies a common high voltage between the discharge electrode and the ground electrode, and between the high-voltage electrode and the collecting electrode.

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