JP2017119247A - Electric dust collector and air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric dust collector capable of evenly achieving restitution of charged fine particles at the minimum applied voltage.SOLUTION: An electric dust collector 44 includes: a charging electrode 73 which is arranged in air flow, discharges the air flow, and charges a substance in the air flow; a dust collecting electrode 35 which is arranged in the downstream of the charging electrode 73 in a flow direction of the air flow, and is formed of a conductive material that partitions a ventilation passage of the air flow; a repulsion electrode 76 which faces the dust collecting electrode 35 on a conductive smooth surface 77 in the downstream of the dust collecting electrode 35 in the flow direction of the air flow, and has a plurality of opening 79 that are bored in the smooth surface 77 and pass in the flow direction; and a voltage source which applies a voltage having the same polarity as that of the charging electrode 73, to the repulsion electrode 76.SELECTED DRAWING: Figure 7

Description

  The present invention relates to an electrostatic precipitator and an air conditioner using the same.

  As disclosed in Patent Document 1, an electrostatic precipitator is generally known. In the electrostatic precipitator, a charging electrode, a dust collecting electrode, and a repelling electrode are arranged from the upstream side in the air flow direction. Since a voltage is applied to the repelling electrode in the same polarity as the charging electrode, the charged fine particles (fine particles charged by the discharge of the charging electrode) are bounced off by the repelling electrode and adhere to the dust collecting electrode. Thus, the dust collection efficiency is increased.

Japanese Utility Model Publication No. 62-75846

  In Patent Document 1, both the dust collection electrode and the repulsion electrode are formed of a conductive material film of a resin filter. Since the resin filter is formed by weaving resin fibers, protrusions are formed at the positions where the fibers overlap each other, and the conductive material coating between the electrodes is locally approached. Such local approach causes a spark discharge.

  It is an object of the present invention to prevent local approach between electrodes and prevent spark discharge.

  One aspect of the present invention is a charging electrode that is disposed in an airflow and discharges the airflow to charge a substance in the airflow, and an airflow that is disposed downstream of the charging electrode along the flow direction of the airflow. A dust collecting electrode formed of a conductive material that divides the path, and a conductive smooth surface downstream of the dust collecting electrode along the flow direction of the airflow so as to face the dust collecting electrode and perforate the smooth surface. The present invention relates to an electrostatic precipitator including a repulsive electrode having a plurality of openings penetrating in the flow direction, and a voltage source that applies a voltage having the same polarity as that of the charging electrode to the repulsive electrode.

  When discharge is performed from the charging electrode, fine particles such as dust in the air current are charged to a specific polarity. The airflow passes through the air passage of the dust collecting electrode. Charged fine particles (charged fine particles) in the air current ride on the air current and pass through the dust collecting electrode. At this time, when a voltage is applied from the voltage source, an electrical barrier is formed along the smooth surface of the repulsive electrode. The charged fine particles collide with an electrical barrier. Since the charged fine particles and the electric barrier have the same polarity, the charged fine particles are rebounded by the electric barrier. The charged fine particles bounced back easily adhere to the dust collecting electrode. In this way, fine particles such as dust are captured by the dust collecting electrode. Since the electrical barrier blocks the path of the microparticles, the linear travel of the microparticles is reliably prevented. As a result, further dust collection efficiency is realized.

  The repulsive electrode faces the dust collecting electrode with a smooth surface. As a result, local access between the repulsion electrode and the dust collection electrode is avoided. Therefore, local electric field concentration can be avoided. Such a repulsive electrode contributes to the formation of an equal electric field. Generation of spark discharge is suppressed.

  In the electric dust collector, the repulsive electrode may be formed of a sheet-like punching metal (punching metal sheet) punched from the smooth surface side. The repulsion electrode can be mass-produced at low cost.

  The dust collection electrode may be connected to the ground. When the fine particles adhere to the dust collection electrode, the charge of the fine particles moves to the dust collection electrode. The charge flows to ground. In this way, the dust collection electrode avoids the formation of a potential having the same polarity as that of the charging electrode. Even if the adhesion amount of fine particles increases, new fine particles can surely adhere to the dust collecting electrode. If there is no escape route for the charge on the dust collection electrode, a potential of the same polarity as that of the charging electrode is generated on the dust collection electrode as the amount of charge adhering increases. Adhesion is hindered.

  The smooth surface should just face the dust collection electrode at equal intervals. In this way, the electrical barrier can suppress the bias of the potential distribution as much as possible. As a result, the fine particles can uniformly adhere to the dust collecting electrode. In addition, the repulsive electrode and the dust collecting electrode do not approach locally, and the occurrence of spark discharge can be prevented.

  The repulsion electrode may be formed from a conductive resin sheet. Compared to conductive materials made of metallic materials, it can have a large electric resistance. Therefore, even if spark discharge occurs due to a large amount of dust adhering to the repulsion electrode or dust collection electrode, the discharge current generated during discharge is reduced. It can be kept low.

 The electric dust collector as described above can be used by being incorporated in an air conditioner. The air conditioner can enjoy the advantages of the electrostatic precipitator described so far.

  As described above, an electrostatic precipitator capable of realizing the repulsion of charged fine particles without locally bringing the repelling electrode and the dust collecting electrode close to each other is provided.

It is a conceptual diagram which shows roughly the structure of the air conditioner which concerns on one Embodiment of this invention. It is a perspective view showing roughly the appearance of the indoor unit concerning one embodiment. It is a perspective view which shows the structure of the main body of an indoor unit schematically. It is a disassembled perspective view which shows the structure of an indoor unit schematically. It is an expansion perspective view showing the structure of an air filter roughly. It is sectional drawing along the AA line of FIG. It is an expansion vertical sectional view of the main part of an indoor unit. It is an expansion perspective view which shows the structure of a dust collection electrode roughly. It is an expanded sectional view showing the principle of electric dust collection roughly. It is a disassembled perspective view which shows roughly the structure of the air cleaner which concerns on one Embodiment of this invention. It is a disassembled perspective view which shows schematically the structure of the air cleaner which concerns on other embodiment. It is a disassembled perspective view which shows roughly the structure of the ventilation apparatus which concerns on one Embodiment of this invention. It is a conceptual diagram which shows roughly the structure of the clean room which concerns on one Embodiment of this invention.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

(1) Configuration of Air Conditioner FIG. 1 schematically shows a configuration of an air conditioner 11 according to an embodiment of the present invention. The air conditioner 11 includes an indoor unit 12 and an outdoor unit 13. The indoor unit 12 is installed in an indoor space in a building, for example. In addition, the indoor unit 12 may be installed in a space corresponding to the indoor space. An indoor heat exchanger 14 is incorporated in the indoor unit 12. The outdoor unit 13 includes a compressor 15, an outdoor heat exchanger 16, an expansion valve 17, and a four-way valve 18. The indoor heat exchanger 14, the compressor 15, the outdoor heat exchanger 16, the expansion valve 17 and the four-way valve 18 form a refrigeration circuit 19.

  The refrigeration circuit 19 includes a first circulation path 21. The first circulation path 21 connects the first port 18a and the second port 18b of the four-way valve 18 to each other. A compressor 15 is provided in the first circulation path 21. The suction pipe 15a of the compressor 15 is connected to the first port 18a of the four-way valve 18 via a refrigerant pipe. The gas refrigerant is supplied to the suction pipe 15a of the compressor 15 from the first port 18a. The compressor 15 compresses the low-pressure gas refrigerant to a predetermined pressure. The discharge pipe 15b of the compressor 15 is connected to the second port 18b of the four-way valve 18 via a refrigerant pipe. Gas refrigerant is supplied from the discharge pipe 15 b of the compressor 15 to the second port 18 b of the four-way valve 18. The refrigerant pipe may be a copper pipe, for example.

  The refrigeration circuit 19 further includes a second circulation path 22. The second circulation path 22 connects the third port 18c and the fourth port 18d of the four-way valve 18 to each other. The outdoor heat exchanger 16, the expansion valve 17, and the indoor heat exchanger 14 are incorporated into the second circulation path 22 in order from the third port 18c side. The outdoor heat exchanger 16 exchanges thermal energy between the refrigerant passing therethrough and the surrounding air. The indoor heat exchanger 14 exchanges thermal energy between the refrigerant passing therethrough and the surrounding air. The second circulation path 22 may be formed by a refrigerant pipe such as a copper pipe.

  A blower fan 23 is incorporated in the outdoor unit 13. The blower fan 23 ventilates the outdoor heat exchanger 16. The blower fan 23 generates an air flow according to the rotation of the impeller, for example. The airflow passes through the outdoor heat exchanger 16. The flow rate of the airflow passing through is adjusted according to the rotational speed of the impeller.

  A blower fan 24 is incorporated in the indoor unit 12. The blower fan 24 ventilates the indoor heat exchanger 14. The blower fan 24 generates an air flow according to the rotation of the impeller. Indoor air is sucked into the indoor unit 12 by the action of the blower fan 24. The indoor air passes through the indoor heat exchanger 14 and exchanges heat with the refrigerant. The heat-exchanged cold air or warm air flow is blown out from the indoor unit 12. The flow rate of the airflow passing through is adjusted according to the rotational speed of the impeller.

  When the cooling operation is performed in the refrigeration circuit 19, the four-way valve 18 connects the second port 18b and the third port 18c to each other and connects the first port 18a and the fourth port 18d to each other. Therefore, high-temperature and high-pressure refrigerant is supplied to the outdoor heat exchanger 16 from the discharge pipe 15 b of the compressor 15. The refrigerant flows through the outdoor heat exchanger 16, the expansion valve 17, and the indoor heat exchanger 14 in order. The outdoor heat exchanger 16 radiates heat from the refrigerant to the outside air. The refrigerant is decompressed to a low pressure by the expansion valve 17. The decompressed refrigerant absorbs heat from the surrounding air in the indoor heat exchanger 14. Cold air is generated. The cold air is blown out into the indoor space by the function of the blower fan 24.

  When the heating operation is performed in the refrigeration circuit 19, the four-way valve 18 connects the second port 18b and the fourth port 18d to each other and connects the first port 18a and the third port 18c to each other. A high-temperature and high-pressure refrigerant is supplied from the compressor 15 to the indoor heat exchanger 14. The refrigerant flows through the indoor heat exchanger 14, the expansion valve 17, and the outdoor heat exchanger 16 in order. The indoor heat exchanger 14 radiates heat from the refrigerant to the surrounding air. Warm air is generated. Warm air is blown into the indoor space by the function of the blower fan 24. The refrigerant is decompressed to a low pressure by the expansion valve 17. The decompressed refrigerant absorbs heat from the surrounding air in the outdoor heat exchanger 16. Thereafter, the refrigerant returns to the compressor 15.

(2) Configuration of Indoor Unit FIG. 2 schematically shows the appearance of the indoor unit 12 according to an embodiment. An outer panel 27 covers the main body (housing) 26 of the indoor unit 12. An air outlet 28 is formed on the lower surface of the main body 26. The blower outlet 28 opens toward the room. The main body 26 can be fixed to an indoor wall surface, for example. Cold air or warm air is generated in the indoor heat exchanger 14, and the air flow of cold air or warm air blows out from the outlet 28.

  A pair of front and rear wind direction plates 31a and 31b are arranged at the outlet 28. The up and down wind direction plates 31a and 31b can rotate about horizontal axes 32a and 32b parallel to the longitudinal direction of the main body, respectively. The vertical airflow direction plates 31a and 31b open and close the air outlet 28 according to the rotation. The direction of the airflow to be blown out is changed according to the angle of the up / down airflow direction plates 31a, 31b.

  As shown in FIG. 3, a suction port 33 is formed in the main body 26. The suction port 33 opens at the front and top surfaces of the main body 26. The outer panel 27 can be covered with the suction port 33 in front of the main body 26. Indoor air is taken into the main body 26 from the suction port 33 and supplied toward the indoor heat exchanger 14.

  An air filter assembly 34 is arranged in the suction port 33 in a direction parallel to the horizontal axes 32a and 32b. The air filter assembly 34 includes an air filter 35 and a dust box 36. The air filter 35 is held in the dust box 36. The dust box 36 is detachably attached to the main body 26. When the dust box 36 is set on the main body 26, the air filter 35 is disposed over the entire surface of the suction port 33.

  A front filter rail 38 is formed in the dust box 36. A rear filter rail 39 is formed on the main body 26 so as to correspond to an extension line of the front filter rail 38. The filter rails 38 and 39 extend along a vertical plane orthogonal to the horizontal axes 32a and 32b. The left and right ends of the air filter 35 are slidably held by the filter rails 38 and 39. The filter rails 38 and 39 guide the forward and backward movement of the air filter 35.

  As shown in FIG. 4, the blower fan 24 is rotatably supported by the main body 26. For example, a cross flow fan is used as the blower fan 24. The blower fan 24 rotates around a rotation shaft 41 parallel to the horizontal axis lines 32a and 32b. The rotating shaft 41 of the blower fan 24 extends in the horizontal direction when the main body 26 is installed. The blower fan 24 is disposed in parallel with the air outlet 28. A driving force around the rotary shaft 41 is transmitted to the blower fan 24 from a driving source (not shown). The drive source is supported by the main body 26. The airflow passes through the indoor heat exchanger 14 according to the rotation of the blower fan 24. As a result, a cold or warm air stream is generated. Cold air or warm air is blown out from the air outlet 28.

  The indoor heat exchanger 14 includes a front side body 14a and a rear side body 14b. The front body 14 a faces the blower fan 24 from the front side of the blower fan 24. The rear body 14 b is opposed to the blower fan 24 from the rear side of the blower fan 24. The front body 14a and the rear body 14b are connected to each other at the upper end. The front side body 14a and the rear side body 14b have a refrigerant pipe 42a. That is, the refrigerant pipe 42a extends parallel to the horizontal axes 32a and 32b, is folded at the left and right ends of the main body 26 when viewed from the front, extends again parallel to the horizontal axes 32a and 32b, and is folded again at the left and right ends of the main body 26 when viewed from the front. These are repeated. The refrigerant pipe 42 a constitutes a part of the second circulation path 22. A plurality of heat radiation fins 42b are coupled to the refrigerant pipe 42a. The heat radiating fins 42b extend in parallel to each other while being orthogonal to the horizontal axes 32a and 32b. The refrigerant pipes 42a and the radiation fins 42b can be formed from a metal material such as copper or aluminum. Heat exchange is realized between the refrigerant and the air through the refrigerant pipe 42a and the radiation fins 42b.

  As shown in FIG. 4, the air filter assembly 34 includes a filter cleaning unit 43 and an electric dust collection unit (electric dust collector) 44. The dust box 36 serves as one component of the filter cleaning unit 43. The dust box 36 includes an upper dust box 45 and a lower dust box 46. The upper dust box 45 is disposed on the front side of the air filter 35. The upper dust box 45 has a cover 47. The cover 47 opens and closes the storage space 49 of the box body 48. The lower dust box 46 is disposed on the rear surface side of the air filter 35. The upper dust box 45 and the lower dust box 46 are sandwiched between the air filters 35. When cleaning the air filter 35, dust on the front surface of the air filter 35 is generally collected in the box body 48 of the upper dust box 45, and dust on the rear surface of the air filter 35 is collected in the lower dust box 46.

  The filter cleaning unit 43 includes a first driven gear 51 and a second driven gear 52. The first driven gear 51 is supported by the upper dust box 45. The first driven gear 51 rotates around the horizontal axis 53. The teeth of the first driven gear 51 are partially exposed from the outer surface of the upper dust box 45. Similarly, the second driven gear 52 is supported by the lower dust box 46. The second driven gear 52 rotates around the horizontal axis 54. The second driven gear 52 drives the air filter 35 at both ends of the lower dust box 46. The teeth of the second driven gear 52 are partially exposed from the outer surface of the lower dust box 46. When the air filter assembly 34 is set on the main body 26, the first driven gear 51 meshes with a first drive gear (not shown) mounted on the main body 26, and similarly, the second driven gear 52 is mounted on the main body 26. Engage with two drive gears (not shown). A drive source (not shown) such as an electric motor is individually connected to each drive gear. The first driven gear 51 and the second driven gear 52 rotate individually according to the driving force supplied from the individual driving sources.

  The electric dust collection unit 44 includes an ionizer (ion generation unit) 55 and a dust collection electrode and a repulsion electrode. The ionizer 55 is fixed to the upper dust box 45. The casing 56 of the ionizer 55 may be formed integrally with the cover 47 of the upper dust box 45. A radiation port 57 is formed in the casing 56 of the ionizer 55. Ions are emitted from the radiation port 57. The dust collection electrode and the repulsion electrode will be described later.

  As shown in FIG. 5, the air filter 35 includes a frame 61 and a mesh sheet 62. The mesh sheet 62 is configured by combining polyethylene terephthalate fibers (resin fibers) in a lattice pattern, for example. The mesh sheet 62 is supported by the frame 61. The frame 61 has a function of holding the shape of the mesh sheet 62. The frame 61 is formed from a resin material (for example, polypropylene). The frame 61 and the mesh sheet 62 constitute an insulator 63. The mesh of the mesh sheet 62 intersects the air current and defines an air passage.

  A rack 64 is formed on the frame 61 of the air filter 35. The racks 64 are disposed on both the left and right sides of the frame 61. The rack 64 meshes with a pinion (not shown) stored in the lower dust box 46. The pinion is connected to the second driven gear 52. The rotation of the second driven gear 52 is transmitted to the pinion. Thus, according to the rotation of the second driven gear 52, the air filter 35 moves back and forth along the filter rails 38 and 39. The air filter 35 moves relative to the upper dust box 45 and the lower dust box 46.

  As shown in FIG. 6, a conductive material film 65 is formed on the rear surface of the air filter 35 (the surface downstream of the airflow). For example, a metal material such as aluminum can be used as the conductive material. The coating 65 is laminated on the rear surface of the mesh sheet 62. For example, a sputtering method may be used to form the film 65. The air passages partitioned in a lattice shape by the mesh sheet 62 are secured as they are. An insulating material is maintained on the entire front surface of the air filter 35 (the upstream surface with respect to the airflow). The coating 65 is connected to the ground of the main body 26. In such connection, the main body 26 may be provided with an electrical contact (not shown) that contacts a part of the coating 65. What is necessary is just to drop the electric potential of the film 65 from an electrical contact to the ground. The electrical contact that contacts the coating 65 may be formed in the dust box 36, and in this case, the wiring extending from the electrical contact of the dust box 36 may be connected to the electrical contact on the main body 26. As will be described later, the coating 65 functions as a dust collection electrode of the electric dust collection unit 44.

  As shown in FIG. 7, the filter cleaning unit 43 includes a cleaning brush 66. The cleaning brush 66 is stored in the upper dust box 45. The cleaning brush 66 includes a brush pedestal 67. The brush pedestal 67 can rotate around the horizontal axis 68 by the driving force from the first driven gear 51. The brush bristles 69 are arranged on a cylindrical surface of the brush pedestal 67 over a predetermined center angle range. The flocking range of the brush bristles 69 has a spread across the air filter 35 in the axial direction of the brush pedestal 67. The cleaning brush 66 brings the bristles 69 into contact with the air filter 35 at a predetermined rotational position, and separates the bristles 69 from the air filter 35 at other than the rotational position. When the air filter 35 moves in a direction along a vertical plane orthogonal to the horizontal axes 32 a and 32 b in a state where the brush bristles 69 are in contact with the air filter 35, dust adhering to the front surface of the air filter 35 is entangled with the bristles 69. Can be done.

  The filter cleaning unit 43 includes a brush receiver 71. The brush receiver 71 is accommodated in the lower dust box 46. The brush receiver 71 has a receiving surface 72. The receiving surface 72 is opposed to the cleaning brush 66. When the bristle 69 contacts the air filter 35, the receiving surface 72 sandwiches the air filter 35 between the bristle 69. In addition, brush hair may be planted on the receiving surface 72.

  The ionizer 55 of the electric dust collection unit 44 has a charging electrode 73. The charging electrode 73 is connected to a high voltage power source 75 mounted on the main body 26. The charging electrode 73 is supplied with a high voltage from the high voltage power source 75 and is discharged into the air. Ions are generated based on the discharge. An detachable electrical contact (not shown) is formed on the wiring between the ionizer 55 and the high voltage power source 75. When the air filter assembly 34 is attached and detached, the connection and division of the wiring are realized by the action of the electrical contacts.

  The electric dust collection unit 44 further includes a repelling electrode 76. The repulsive electrode 76 is disposed downstream of the coating 65 of the air filter 35 along the flow direction of the airflow, and faces the coating 65 with a conductive smooth surface 77. The smooth surface 77 of the repulsive electrode 76 extends in parallel to a virtual plane including the filter rail 38. Therefore, the smooth surface 77 faces the coating 65 at equal intervals.

  The repulsive electrode 76 is connected to a high voltage power supply 78 mounted on the main body 26. A high voltage is supplied to the repulsive electrode 76 through the wiring. A voltage having the same polarity as the ions emitted from the ionizer 55 is applied to the repelling electrode 76. Therefore, the repulsion electrode 76 forms an electrical barrier having the same polarity as the ions along the smooth surface 77 when supplied with a high voltage. A detachable electrical contact is formed on the wiring between the repulsion electrode 76 and the high voltage power supply 78. When the air filter assembly 34 is attached and detached, the connection and division of the wiring are realized by the action of the electrical contacts.

  As shown in FIG. 8, the repulsive electrode 76 has a plurality of openings 79 that are pierced in the smooth surface 77 and penetrate in the flow direction of the airflow. Here, a punching metal sheet punched from the smooth surface 77 side is used for the repulsive electrode 76. The punching metal sheet may be formed from a metal plate such as stainless steel. In the repulsion electrode 76, the aperture ratio per unit area may be set to 40% or more and 60% or less, for example. If the aperture ratio is less than 40%, the effect of the electrical barrier is enhanced, but the flow of airflow is hindered. On the other hand, when the aperture ratio exceeds 60%, a large voltage is required to form an electrical barrier although the flow resistance of the airflow is reduced. In addition, a conductive resin sheet may be used for the repulsive electrode 76 instead of the punching metal sheet. The conductive resin sheet only needs to have a predetermined rigidity for maintaining its shape by having conductivity due to the action of a metal material, carbon or other conductive material filler. The conductivity may be imparted by a metal plating film.

(3) Operation of indoor unit When the blower fan 24 is operated, the airflow is sucked into the main body 26 from the suction port 33. In the main body 26, an airflow is generated from the suction port 33 toward the blowout port 28. The airflow passes through the air filter 35 and passes through the indoor heat exchanger 14. During the cooling operation, the air is cooled by the indoor heat exchanger 14 and blown out from the outlet 28. During the heating operation, the air is warmed by the indoor heat exchanger 14 and blown out from the outlet 28. When the airflow passes through the air filter 35, dust larger than the mesh size of the mesh sheet 62 cannot pass through the mesh. Large dust is captured on the front surface of the air filter 35. Fine particles such as dust smaller than the size of the mesh adhere to the rear surface of the air filter 35 by the principle of electrostatic dust collection described later. In this way, dust and the like are removed from the airflow flowing toward the indoor heat exchanger 14. A clean airflow flows into the indoor heat exchanger 14. Cool air or warm air of clean air is blown out from the air outlet 28.

  The operation of the filter cleaning unit 43 when the air filter 35 is cleaned will be described. The bristle 69 of the cleaning brush 66 comes into contact with the front surface of the air filter 35 in accordance with the rotation operation of the brush base 67. At this time, the rear surface of the air filter 35 is received by the receiving surface 72 of the brush receiver 71. The air filter 35 is sandwiched between the bristle 69 and the receiving surface 72. When the second driven gear 52 is driven, the air filter 35 moves back and forth along the filter rails 38 and 39. As the air filter 35 moves, the brush bristles 69 trace the front surface of the air filter 35. Thus, the bristle 69 entangles large dust from the front surface of the air filter 35. The entangled dust is collected in the upper dust box 45. Since the electric charge escapes to the ground on the rear surface of the air filter 35, the particles fall from the rear surface of the air filter 35 when the receiving surface 72 comes into contact with the air filter 35. The dropped fine particles are collected in the lower dust box 46.

  Airflow is sucked into the main body 26 from the suction port 33. At this time, ions 81 are radiated from the ionizer 55 to the suction port 33 in parallel. Since the ion 81 has directivity, it proceeds so as to cross the suction port 33. The ions 81 pass through the air current over a wide range. It contacts a wide range of fine particles such as dust contained in the airflow. The fine particles in the airflow are charged efficiently. As a result, the dust collection efficiency can be increased.

  In the present embodiment, the repelling electrode 76 faces the coating 65 of the air filter 35 with a smooth surface 77. As a result, local access between the repelling electrode 76 and the coating 65 is mitigated. Therefore, local electric field concentration can be avoided. The repulsive electrode 76 having such a shape contributes to the formation of an equal electric field. The repulsion of the charged fine particles is realized evenly over the entire smooth surface 77 with the minimum applied voltage.

  The repulsive electrode 76 is formed of a punching metal sheet punched from the smooth surface 77 side. Since the punching is performed from the smooth surface 77 side, the occurrence of burrs on the smooth surface 77 is avoided when the opening 79 is formed. Therefore, local electric field concentration is surely avoided. Moreover, the repelling electrode 76 can be mass-produced at a low cost. However, the repulsive electrode 76 may be formed of a conductive resin sheet. The conductive resin sheet can have a large electric resistance as compared with a conductive material of a metal material, and thus an electrical barrier can be established reliably at a low current.

(4) Principle of Electric Dust Collection As shown in FIG. 9, a repelling electrode 76 is disposed downstream of the air filter 35 along the air flow direction. When discharging is performed from the charging electrode 73, fine particles such as dust in the air current are charged to a specific polarity. Here, positive ions 81 are generated in the airflow by the discharge. Positive ions 81 adhere to fine particles 82 such as dust in the airflow. Thus, the fine particles 82 are positively charged (hereinafter, the charged fine particles are referred to as “charged fine particles 83”). The airflow passes through the air filter 35. The charged fine particles 83 in the airflow ride on the airflow and pass through the air filter 35.

  At this time, when a voltage is applied to the repulsion electrode 76 from the high voltage power source 78 as a voltage source, the smooth surface 77 of the repulsion electrode 76 is positively charged. An electrical barrier 84 is formed along the smooth surface 77 of the repelling electrode 76. The charged fine particles 83 collide with the electrical barrier 84. Since the charged fine particles 83 and the electric barrier 84 have the same polarity, the charged fine particles 83 are rebounded by the electric barrier 84. The charged fine particles 83 bounced back easily adhere to the coating 65 of the air filter 35. Thus, fine particles such as dust are captured by the coating 65, that is, the dust collecting electrode.

  The coating 65 of the air filter 35 is connected to the ground 85. When the charged fine particles 83 adhere to the coating 65 of the air filter 35, the charge of the charged fine particles 83 moves to the coating 65. The charge flows to the ground 85. The charged state of the charged fine particles 83 is eliminated. In this way, formation of a potential having the same polarity as that of the charging electrode 73 is avoided in the coating 65. Even if the adhesion amount of the fine particles increases, new charged fine particles 83 can reliably adhere to the coating 65 of the air filter 35. If the film 65 does not provide a charge escape path, a potential having the same polarity as that of the charging electrode 73 is generated on the film 65 as the amount of charge adhered increases, and the adhesion of fine particles according to the repulsive force having the same polarity. Will be hindered.

  In the present embodiment, the smooth surface 77 is installed in parallel to the surface of the coating 65. Accordingly, the smooth surface 77 faces the surface of the coating 65 at equal intervals. In this way, the electrical barrier 84 can suppress the potential distribution bias as much as possible. As a result, the charged fine particles 83 can uniformly adhere to the coating 65 of the air filter 35. In addition, discharge can be prevented from occurring between the repelling electrode 76 and the coating 65.

  FIG. 9 shows an example in which positive ions are released from the ionizer 55. Instead of such positive ions, an ionizer that emits negative ions may be used. In that case, the repulsive electrode 76 may be connected to the negative potential, and the dust collecting electrode (the coating 65 of the air filter 35) may be connected to the positive potential or the ground potential.

(5) Configuration of Air Cleaner FIG. 10 schematically shows a configuration of an air cleaner 91 according to an embodiment of the present invention. The air cleaner 91 includes a main body 92 and a front cover 93. A front cover 93 is coupled to the front surface of the main body 92. A housing space 94 is defined in the main body 92. The accommodation space 94 is closed by the front cover 93. The front cover 93 is formed with a front vent 95 connected to the accommodation space 94.

  A rear vent 96 is formed in the housing space 94 on the wall surface facing the front cover 93. A blower fan 97 is disposed in the rear vent 96. When the blower fan 97 is activated, air is taken into the accommodation space 94 from the front vent 95. Air flows from the accommodation space 94 into the rear vent 96. Air is discharged from the rear vent 96 to the outside. Thus, an air flow is generated from the front vent 95 toward the rear vent 96 in the accommodation space 94.

  An electric dust collection unit (electric dust collector) 98 is accommodated in the accommodation space 94. The electric dust collection unit 98 includes a plurality of charging electrodes 99 on the windward side. The charging electrode 99 may be formed vertically long along the left and right wall surfaces of the accommodation space 94. Airflow flows through the space between the charging electrodes 99. Due to the action of the charging electrode 99, fine particles such as dust in the air current are charged to a specific polarity.

  The electric dust collection unit 98 includes a first air filter 101, a first repelling electrode 102, a second air filter 103, and a second repelling electrode 104. The first air filter 101 and the second air filter 103 may be configured in the same manner as the air filter 35 described above. That is, a conductive material film is formed on the rear surface of the first insulator. The coating is connected to ground. The mesh of the mesh sheet intersects the air current and defines an air passage. Similarly, the first repulsion electrode 102 and the second repulsion electrode 104 may be configured in the same manner as the repulsion electrode 76 described above. That is, the first and second repulsive electrodes 102 and 104 have a plurality of openings 79 that face the conductive material coating on the conductive smooth surface 77 and penetrate the smooth surface 77 in the air flow direction. . In the housing space 94, the airflow sequentially passes through the charging electrode 99, the first air filter 101, the first repelling electrode 102, the second air filter 103, and the second repelling electrode 104. The smooth surface 77 of the first repulsive electrode 102 faces the coating of the first air filter 101 at equal intervals. Similarly, the smooth surface 77 of the second repulsive electrode 104 is opposed to the coating of the second air filter 103 at equal intervals. Here, the first repulsive electrode 102 may function as a charging electrode with respect to the second repulsive electrode 104. Specifically, in addition to causing an electrical barrier by the first repulsive electrode 102, a voltage is applied so that positive ions are generated in the airflow by discharging from the first repulsive electrode 102 to the airflow. That's fine. In addition, a charging electrode may be further disposed between the first repulsive electrode 102 and the second air filter 103. In accordance with the above-described principle of electrostatic dust collection, fine particles such as dust are captured by the first air filter 101 and the second air filter 103 in the electric dust collection unit 98. Thus, dust collection efficiency can be improved more by arranging a plurality of dust collection electrodes and repulsion electrodes with respect to air current. In the air cleaner 91, the filter cleaning unit 43 may be combined with the first air filter 101 in the same manner as described above.

  As shown in FIG. 11, in the air cleaner 91a, a HEPA filter 105 may be used instead of the second air filter 103 and the second repulsive electrode 104. The HEPA filter 105 can capture fine particles passing through the first air filter 101 without being charged. The electric dust collection unit 98 can function as a pre-filter for the HEPA filter 105. In that case, since the particulate matter is captured by the pre-filter, the replacement frequency of the HEPA filter 105 can be made lower than when the particulate matter is captured by the HEPA filter 105 alone.

(6) Configuration of Ventilator FIG. 12 schematically shows a configuration of a ventilator 107 according to an embodiment of the present invention. The ventilation device 107 includes a housing 108. An electric dust collection unit (electric dust collector) 109 and a blower fan 111 are accommodated in the housing 108. The electrostatic dust collection unit 109 includes a charging electrode 112, a first air filter 113, a first repelling electrode 114, a second air filter 115 and a second repelling electrode 116. The charging electrode 112, the first air filter 113, the first repulsion electrode 114, the second air filter 115, and the second repulsion electrode 116 function in the same manner as described above. When the blower fan 111 operates, the airflow sequentially passes through the charging electrode 112, the first air filter 113, the first repulsive electrode 114, the second air filter 115, and the second repelling electrode 116. Fine particles in the airflow are captured by the first air filter 113 and the second air filter 115. Such a ventilator 107 may be installed in an air duct that interconnects the room and the outdoors. When introducing outside air, it can capture fine particles such as dust in the air.

(7) Configuration of Clean Room FIG. 13 schematically shows the configuration of the clean room 118 according to an embodiment of the present invention. The room 119 is constituted by a sealed space. An air duct 121 is connected to the room 119. The air duct 121 opens at a first position in the room 119 and opens at a second position away from the first position. The above-described ventilator 107 may be incorporated in the air duct 121. Air circulates through the air duct 121. Air is purified by the ventilator 107 for each circulation.

  11 Air conditioner, 35 Dust collection electrode (air filter), 44 Electric dust collection unit (electric dust collector), 73 Charging electrode, 76 Repulsion electrode, 77 Smooth surface, 78 Voltage source, 79 Opening, 85 Ground.

Claims (4)

A charging electrode disposed in an air stream to discharge the air stream and charge a substance in the air stream;
A dust collecting electrode that is disposed downstream of the charging electrode along the flow direction of the airflow, and is formed of a conductive material that partitions the airflow path of the airflow;
A repulsion having a plurality of openings facing the dust collecting electrode with a conductive smooth surface downstream of the dust collecting electrode along the flow direction of the air flow and penetrating in the smooth direction by passing through the smooth surface. Electrodes,
An electric dust collector comprising: a voltage source that applies a voltage having the same polarity as that of the charging electrode to the repulsive electrode.   The electrostatic precipitator according to claim 1, wherein the repulsive electrode is formed of a punching metal sheet punched from the smooth surface side.   2. The electrostatic precipitator according to claim 1, wherein the repulsive electrode is formed of a conductive resin sheet.   An air conditioner comprising the electric dust collector according to any one of claims 1 to 3.

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