JP2010029839A - Electrostatic dust collecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems in an electrostatic dust collecting device wherein, when using semiconductive electrode plates, lowering of an electric field occurs in a wide range in structure of the electrode plates bridgingly contacting with each other due to spacers for setting spaces for introducing air, to greatly lower the dust collection performance. <P>SOLUTION: In the electrostatic dust collecting device provided with a dust collection part 4 formed by fixing layers formed by alternately stacking dust repelling electrode plates 2 and dust collection electrode plates 3 with a frame 12, at least any one of the dust repelling electrode plates 2 and dust collection electrode plates 3 is the semiconductive electrode plate composed of a material having semiconductivity or insulation property and having a surface resistivity of 10<SP>7-11</SP>Ω/sq., and the dust repelling electrode plates 2 are connected to the dust collection electrode plates 3 with insulators 13 provided outside the frame. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a dust collector for removing particulate suspended matters in the air in the field of air purification.

  Particulate suspended matter in the air, that is, dust, has been known as a cause of illnesses such as asthma and has been a target for removal in the past, but in recent studies, the particle size is 2.5 micrometers or less. There is a report that dust (so-called PM2.5) may induce diseases such as lung cancer, and further improvement of the collection technology is required. Among them, dust collectors that use electrostatic precipitating technology are excellent at collecting small particles with a particle size of micrometer or less, and have a low-pressure loss characteristic. There is a need for improved performance.

  Conventionally, as a dust collector of this type, a charging unit that charges dust by electric discharge is provided in the previous stage, and electrodes are stacked in the subsequent stage, and different voltages are applied alternately to form an electric field to collect charged dust. The thing which provided the dust collection part which collects is known. As an example to which this configuration is applied, Patent Document 1 discloses a dust collector in which an electrode to which one voltage is applied in a dust collector is covered with a resin film as an insulator. Hereinafter, the dust collector will be described with reference to FIG. As shown in FIG. 18, the charging unit 101 includes a linear charging unit discharge electrode 102 and a charging unit counter electrode plate 103, and a voltage application electrode plate 105 and a dust collecting electrode plate on the downstream side of the charging unit 101. A dust collecting section 104 is provided in which 106 and 106 are alternately stacked at a predetermined interval. Although not shown in the figure, the voltage application electrode plate 105 is covered with a resin film which is an insulator. Usually, in the charging unit 101, 5 to 15 kV is provided between the charging unit discharge electrode 102 and the charging unit counter electrode plate 103, and 2 between the voltage applying electrode plate 105 and the dust collecting electrode plate 106 of the dust collecting unit 104. A predetermined voltage is applied to each electrode by the high voltage power source 107 so as to give a potential difference of ˜6 kV.

  In the above configuration, in the charging unit 101, an unequal electric field is created between the charging unit discharge electrode 102 and the charging unit counter electrode plate 103. At this time, in the vicinity of the charging unit discharge electrode 102 having a linear shape, A very strong electric field is created. For this reason, the charge-holding substance that is slightly contained in the air, such as air ions, is accelerated and collides with the air molecules, and the electrons are separated from the air molecules. The separated electrons are also accelerated and collide with air molecules, and the electrons are separated from the air molecules. The phenomenon where electrons are separated from air molecules by collision with electrons is called ionization.

  In addition, the phenomenon in which a large number of electrons separate from air molecules by repeated ionization is called electron avalanche, but positive-polarity air ions that are separated by this avalanche, or negative-polarity air that combines with separated electrons. Ions are created. Then, air ions having a polarity different from that of the charged portion discharge electrode 102 are absorbed by the charged portion discharge electrode 102 and returned to air molecules, and conversely, air ions having the same polarity are repelled from the charged portion discharge electrode 102 by the electric field. Is received and diffused and moved in the direction of the charged portion counter electrode plate 103. The discharge phenomenon in which the air near the charged portion discharge electrode 102 is turned into air ions by causing ionization and electron avalanche is called corona discharge. The discharge phenomenon is generated by corona discharge and mainly has the same polarity as the charged portion discharge electrode 102. As the ions adhere to the dust passing through the charging unit 101, the dust is charged. The charged dust is introduced into the dust collecting portion 104 along the flow of the air flow, and adheres mainly to the dust collecting electrode plate 106 under the force of the electric field created between the voltage applying electrode plate 105 and the dust collecting electrode plate 106. Then, clean air is blown out from behind the dust collecting unit 104. Since the voltage application electrode plate is covered with an insulating resin film, it does not cause a short circuit even when it comes into contact with the dust collection electrode plate, and at the same time prevents spark discharge (hereinafter referred to as spark) that may occur between the electrode plate and the dust collection electrode plate. It has a structure to do.

Moreover, the dust collector as described in patent document 2 is known as another example of the conventional dust collector. The dust collector described in Utility Model Document 2 will be described with reference to FIGS. Incidentally, FIG. 20 is a view showing a cross section taken along line AB of the collector electrode plate 107 in FIG. As shown in FIGS. 19 and 20, the collector electrode plate 107 constituting the dust collecting portion of the dust collector has a semiconductive layer 110 provided on the surface of an insulating electrode substrate 109 having a conductive surface 108 in the center. Yes. A plurality of spacer protrusions 111 obtained by recessing the electrode substrate 109 are provided. As shown in FIG. 21, the collector electrode plate 107 is laminated while opening a certain space where the tip of the spacer protrusion 111 and the back surface of the collector electrode plate 107 are in contact with each other, and different voltages are alternately applied to the collector electrode 107 for each lamination. By applying to the conductive surface 108 provided, an electric field is provided in the space and dust is collected. Then, electric charges are applied from the conductive layer 108 to which a voltage is applied on the semiconductive layer 110 and are distributed so as to spread. For this reason, the electric field region provided between the stacked collector electrode plates 107 is widened, and high dust collection performance is obtained. At the same time, since the semiconductive layer 110 has semiconductivity, a rapid movement of electric charge does not occur. That is, it is possible to prevent a spark that may occur between the collector electrode plate 107 to which a different voltage is applied.
Japanese Patent No. 3261167 Japanese Patent No. 2662553

  In the dust collector as described in Patent Document 1, since the insulation of the voltage application electrode plate is ensured by coating with an insulating resin film, a solid coating is required to ensure insulation. Requires advanced processing techniques. Further, the voltage application electrode plate is usually a metal plate, but it is necessary to increase the plate thickness in order to obtain rigidity. As a result, the weight of the dust collecting part increases and the handling property is impaired.

  Moreover, the problem of the dust collection part 104 which laminated | stacked the collector electrode plate 107 as described in patent document 2 is demonstrated using FIG. As shown in FIG. 21, in order to remove dust in the air, it is necessary to have a structure that allows air to pass between the stacked collector electrode plate A112 and collector electrode plate B113. Therefore, it is necessary to provide a space between the collector electrode plate A112 and the collector electrode plate B113 using many spacer protrusions 111. That is, the collector electrode plate A112 and the collector electrode plate B113 are brought into contact with each other at a number of locations by the numerous spacer protrusions 111.

  Further, a high voltage of several kV is applied to the collector / collector electrode plate A112 to collect dust, and the collector electrode plate B113 is connected to the ground to be 0 kV, whereby the collector electrode plate A112 and the collector electrode plate B113 are connected to each other. Although an electric field is provided between them, the charge distributed on the semiconductive layer 110 escapes when the spacer contacts the semiconductive layer 110 provided on each collector electrode plate.

  For example, the surface potential of the semiconductive layer 110 of the collector electrode plate A112 to which a high voltage is applied is lowered. On the contrary, the surface potential of the semiconductive layer 110 of the collector electrode plate B113 rises, the electric field provided between the collector electrode plate A112 and the collector electrode plate B113 is weakened, and the dust collection performance is lowered. If the insulating property of the spacer protrusion 111 is high, the degree of charge escape is small, but if the electrical resistance of the surface of the spacer protrusion 111 is reduced even if dust is collected, the degree of charge escape becomes very large. The surface potential of the semiconductive layer 110 of the plate A112 is greatly reduced. Since the semiconductive layer 110 has an extremely high electric resistance value compared to the conductor, the decrease in the surface potential of the semiconductive layer 110 of the collector electrode plate A112 and the increase of the surface potential of the semiconductive layer 110 of the collector electrode plate B113 are caused by spacers. This occurs in a wide range on a line connecting the contact point and the conductive surface 108 provided at the center of each collector electrode plate. That is, the intensity of the electric field provided between the collector electrode plates becomes zero at the contact point of the spacer, and gradually increases as it approaches the conductive surface 108 from the contact point.

  Therefore, when the collector electrode plate A112 and the collector electrode plate B113 are in contact with each other by the spacer protrusion 111, the electric field is lowered in a wide range, and the dust collection performance is significantly lowered. In order to solve this problem, it is necessary to have a structure in which the collector electrode plates are not in contact with each other as much as possible.

  The present invention solves such a conventional problem, and provides a dust collector that can be easily produced, is lightweight, prevents sparking between electrode plates, and obtains high dust collection performance. The purpose is that.

  In order to achieve the above object, the dust collector of the present invention is a dust collector including a dust collecting section in which dust repelling electrode plates and dust collecting electrode plates are alternately laminated and fixed by a frame. At least one of the dust collecting electrode plates is made of a material having semiconductivity or insulation, and at the same time has a surface resistivity of 10 7 to 11th power Ω / □, and the dust repelling electrode plate and the dust collecting electrode plate The electrode plate is connected with an insulator provided outside the frame.

  ADVANTAGE OF THE INVENTION According to this invention, the dust collector which can be produced easily, is lightweight, can prevent the spark which arises between electrode plates, and can acquire high dust collection performance can be provided.

  In order to achieve the above object, the dust collector of the present invention is a dust collector including a dust collecting section in which dust repelling electrode plates and dust collecting electrode plates are alternately laminated and fixed by a frame. At least one of the dust collecting electrode plates is made of a material having semiconductivity or insulation, and at the same time is a semiconducting electrode plate having a surface resistivity of 10 7-11 Ω / □, and dust repulsion The electrode plate and the dust collecting electrode plate are connected by an insulator provided outside the frame.

  In order to introduce charged dust (hereinafter referred to as charged dust), the dust repellent electrode plate and the dust collecting electrode plate are provided facing each other with a space between them, and in order to collect charged dust, An electric field is provided between the dust collecting electrode plates. Specifically, different voltages are applied to each electrode plate so that the dust moves from the dust repellent electrode plate to the dust collecting electrode plate. For example, when charged dust is charged with a positive polarity, +6 kV is applied to the dust repellent electrode and 0 kV is applied to the dust collecting electrode plate. When the charged dust is charged with a negative polarity, the dust repellent electrode plate -6 kV and 0 kV are applied to the dust collecting electrode plate, respectively. Conventional dust repellent electrode plates and dust collecting electrode plates are often made of a conductive material such as a metal plate. If different voltages are applied to each electrode plate by connecting the terminals of a high voltage power source, the entire electrode plate is predetermined. Is applied and an electric field is provided.

  However, for example, when dust accumulates on the electrode plate in a sharp shape that becomes the starting point of the spark, a discharge accompanied by a spark, that is, a spark, can occur between the electrode plates. This is because each electrode plate is a conductor, and the charge supplied from the terminals of the high-voltage power supply can move rapidly through the electrode plate. When a spark occurs, a large amount of charge flows rapidly. Yes.

  In the present invention, since at least one of the dust repellent electrode plate and the dust collecting electrode plate is made of a material other than a conductor and has a surface resistivity of 10 7 to 11 11 Ω / □, Electric charges are uniformly supplied from the terminals to the surface of the electrode plate, and a potential difference, that is, an electric field is provided between the dust repellent electrode plate and the dust collecting electrode plate. At the same time, even if dust accumulates on the electrode plate in a sharp shape that becomes the starting point of the spark, the material constituting the electrode plate is not a conductor and the surface resistivity is 10 to 7 to the 11th power Ω / □ Therefore, it is possible to prevent sparks by preventing rapid charge movement.

  In addition, when the dust repellent electrode plate and the dust collecting electrode plate are brought into contact with each other so as to be bridged by a spacer in order to provide a space, charge movement occurs at the contact portion, and the surface potential is lowered around the contact portion. Is weakened. For this reason, the dust collection performance is degraded. In the present invention, the dust repellent electrode plate and the dust collection electrode plate are connected only by the insulator provided outside the frame, that is, outside the frame. The surfaces of the dust repellent electrode plate and the dust collecting electrode plate are not in contact with each other by the insulator provided in the holder, and are held while opening a certain space. Therefore, the surface potential is not lowered by the contact of the spacer with the surface of each electrode plate so as to form a bridge, and the electric field is kept constant. For this reason, it is possible to obtain high dust collection performance.

  As a specific method of providing a space between the dust repellent electrode plate and the dust collecting electrode plate without using a spacer, a through hole is provided in each of the dust repellent electrode plate and the dust collecting electrode plate as described in claim 3, For example, a dust repellent electrode plate and a conductive cylindrical spacer, and a dust collecting electrode plate and a conductive cylindrical spacer may be provided in this order while inserting a conductive shaft. The shaft is inserted in the order of the dust repellent electrode plate and the cylindrical spacer, the dust collecting electrode plate and the cylindrical spacer in this order, and a structure in which the dust repellent electrode plate and the dust collecting electrode plate are alternately laminated is made.

  At this time, since a voltage cannot be applied if the dust repellent electrode plate and the dust collecting electrode plate are in contact with each other, for example, a through hole larger than the outer diameter of the cylindrical spacer is dusted so as not to contact the shaft and the cylindrical spacer. Provided on the repulsive electrode plate. Since the dust repellent electrode plate cannot be supported as it is, the shaft is inserted in the same order using another shaft to support the electrode plate. At this time, the through hole of the dust repellent electrode plate is made the same as the diameter of the shaft, and conversely, a through hole larger than the outer diameter of the cylindrical spacer is provided in the dust collecting electrode plate. Since each electrode plate cannot be firmly fixed in this state, it is desirable that the number of shafts that support each electrode plate is two or more, that is, a total of four or more. And the shaft which supports each electrode plate is connected and fixed using a lever. By adopting such a structure, it becomes possible to support and fix each electrode plate while providing a space without any contact between the surfaces of the dust repellent electrode plate and the dust collecting electrode plate.

  The semiconductive electrode plate is characterized in that a semiconductive layer having a surface resistivity of 10 7-11 Ω / □ is provided on the surface of the insulating substrate. In order to provide an electric field between the dust repellent electrode plate and the dust collecting electrode plate, a potential difference may be generated between the respective electrode plate surfaces. In other words, since it is only necessary to charge only the surface, it is easy to use an insulating substrate as a support base for the electrode plate and to provide a semiconductive layer having a surface resistivity of 10 7 to 11th power / square on the surface. It is possible to form an electrode plate having a surface resistivity of 10 7-11 Ω / □. Examples of the material for the insulating substrate include resin, ceramic, and a laminated sheet obtained by hardening a glass fiber sheet with an epoxy resin.

  In addition, a semiconductive electrode plate is formed by providing a resin film having a volume resistivity of 10 7 to 11 11 Ω · cm on the surface of an insulating substrate. Examples of the material of the film having a volume resistivity of 10 7 to 11 11 Ω · cm include nylon, polyvinylidene fluoride, or vinyl chloride or vinylidene chloride to which a plasticizer is added. Or a polymer with a highly water-absorbing amide bond such as nylon or polyether ester amide, a resin having a semiconductivity such as polyvinylidene fluoride or vinyl chloride or vinylidene chloride, and an insulating resin such as polypropylene, polyester or polystyrene. Examples thereof include a copolymer resin blended and copolymerized. As another example, an inorganic component having a silanol group such as zeolite or a semiconductive material such as a metal oxide such as tin oxide or zinc oxide is mixed with the insulating resin described above and molded into a film. Can be mentioned. Such a resin film has a property of passing a slight amount of electric charge therein, and has a volume resistivity of 10 7 to the 11th power Ω · cm. By providing such a resin film on the surface of the insulating substrate by a method such as adhesion or welding, a semiconductive layer having a surface resistivity of 10 7-11 Ω / □ is provided on the surface of the insulating substrate. Is easily possible.

  In addition, a semiconductive electrode plate is obtained by applying a semiconductive paint having a coating surface of 10 7 to 11th power Ω / □ on the surface of an insulating substrate and drying to provide a semiconductive layer. To do. As a specific example, a surface resistivity of 10 7-11 Ω / □ is obtained by applying a coating containing a water-absorbing polymer such as polyvinyl alcohol, sodium polyacrylate, and amylose on the surface of the insulating substrate and drying it. The method of obtaining the semiconductive film | membrane which has is mentioned. The water-absorbing polymer has a property of easily absorbing moisture in the air, and has a property of passing electricity slightly by absorbing moisture in the air. A semiconductive layer having a surface resistivity of 10 7 to 11 11 Ω / □ is obtained by applying a coating containing a water-absorbing polymer to the surface of the insulating substrate and drying.

  In addition, the semiconductive paint includes a binder component that fixes the semiconductive material and the semiconductive material to the application surface. In the case of the water-absorbing polymer as described above, since the semiconductive material is a polymer, a semiconductive layer that is somewhat strong on the surface of the insulating substrate is obtained by dissolving it in a solvent to form a solution, and applying and drying it. It is possible to provide, but when the semiconductive material is powder, some means for fixing the powder is necessary, and in addition to that, when it is desired to increase the mechanical strength of the semiconductive layer itself There is. As an effective means in such a case, a resin that is soluble in a solvent, such as a thermoplastic polyester resin or a polyol resin, is used as a binder component, and a resin that is dissolved in a solvent and mixed with a semiconductive material is used as a semiconductive paint. Thus, the powdery semiconductive material can be fixed in the semiconductive layer, and the mechanical strength of the semiconductive layer can be improved.

  The semiconductive material is an ion conductive polymer. Examples of the ion conductive polymer include a polymer having a quaternary ammonium salt in the molecular structure. The quaternary ammonium salt has four alkyl groups bonded to the central ammonia atom, and has a positive charge as a whole. Since it has a structure in which anions such as chlorine ions are ion-bonded therewith, it has an ionic conductivity and therefore has a property of passing a slight charge. In addition, since the quaternary ammonium salt having ionic conductivity is included in the molecule in advance, it is not easily affected by humidity, and it is possible to ensure characteristics that allow a slight charge to pass even at low humidity. Have. In order to form an ion conductive polymer, there is a method of polymerizing a monomer having a quaternary ammonium salt and an unsaturated carbon bond in the molecular structure, but the quaternary ammonium salt and the unsaturated carbon bond are included in the molecular structure. Examples of the monomer having dimethylamino methacrylate include chloride salt. Dissolve an aqueous solution of dimethylamino methacrylate chloride salt in alcohol, add low molecular weight methyl methacrylate to ensure film-forming properties, and then add a polymerization initiator such as azobisisobutyronitrile to cause a polymerization reaction. Thus, a polymer solution containing a quaternary ammonium salt can be obtained. In addition, it is possible to ensure adhesion to the coated surface by adding a polymer solution obtained by polymerizing a monomer having a carboxyl group such as acrylic acid and an unsaturated carbon bond in the molecule. . Moreover, since the coating film formed on the coating surface is made of a polymer having a large molecular weight, it exhibits water insolubility. The semiconductive layer formed by applying and drying the semiconductive paint thus prepared has a characteristic that it allows a slight charge to pass even at low humidity, and has water resistance without being peeled off from the coated surface. By applying such an ion conductive polymer to the surface of an insulating substrate and drying, a semiconductive layer having a surface resistivity of 10 7 to 11 11 Ω / □ and being hardly affected by humidity is obtained. It can be formed easily.

  Further, the semiconductive material is a semiconductive metal oxide. The semiconductive layer containing the water-absorbing polymer tends to vary in surface resistivity depending on the humidity level. As a method of providing a semiconductive layer that is not easily affected by humidity, a method of using a semiconductive metal oxide as a semiconductive material can be given. By using a semiconductive metal oxide such as zinc oxide or potassium titanate as a semiconductive material, it has a surface resistivity of 10 7-11 Ω / □ and is not easily affected by humidity. A conductive layer is obtained.

  Further, the metal oxide is tin oxide or tin oxide doped with antimony. Tin oxide has a small change in resistance value due to the magnitude of the applied voltage. This is because the conductive mechanism of tin oxide is due to oxygen defects in the crystal lattice. Further, tin oxide has a property that it is difficult to dissolve in acid or alkali. Therefore, a chemically and electrically stable semiconductive layer can be obtained by using tin oxide as a semiconductive material. Further, an n-type semiconductor structure can be obtained by doping antimony into tin oxide. Therefore, the conductivity is improved as compared with the case where no antimony is doped, and the semiconductivity as the semiconductive layer can be obtained with a smaller amount.

  Further, the semiconductive material is characterized in that tin oxide doped with tin oxide or antimony is attached to carrier particles having a larger particle diameter. In order for the semiconductive layer obtained by tin oxide to have semiconductivity, it is necessary for the particles of tin oxide to be in contact with each other in the semiconductive layer. Requires a large amount of expensive tin oxide particles, which requires high costs. If the tin oxides are in contact, equivalent semiconductivity can be obtained. Therefore, semi-conductivity can be obtained with a small amount of tin oxide by attaching tin oxide, which is a smaller particle, to the surface of large support particles made of chemically stable materials such as titanium oxide. It becomes.

  Further, the carrier particles are needle-shaped. As described above, in order to obtain semiconductivity, tin oxides need to contact each other. Here, the needle-shaped particles are easier to come into contact with each other than the spherical particles. Therefore, it is possible to obtain semiconductivity with a smaller amount of tin oxide by attaching a material having a needle shape such as acicular titanium oxide particles to the surface of the material as a support particle and tin oxide as a smaller particle. Become.

  In addition, a semiconductive paint using a binder component as a resin and a molecular crosslinking agent added thereto is used. When a resin such as a thermoplastic polyester resin, a vinyl chloride resin, or a polyol resin is used as the binder component, a resin having a high solubility in a solvent, that is, a relatively low molecular weight is used in order to form a coating material. Low molecular weight resins are easy to dissolve in oil and surfactant. For example, when oil particles and surfactant particles in the air are collected, the oil particles and surfactant particles attached to the surface are resin in the semiconductive layer. As a result, the semiconductive layer is deteriorated. Here, by adding a polymer cross-linking agent such as polyisocyanate to the semiconductive paint, the OH groups in the resin are cross-linked, and the resin is polymerized. Therefore, it is possible to obtain a chemically stable semiconductive layer in which the resin does not dissolve in oil or surfactant.

  Further, a semiconductive layer is provided by applying a semiconductive paint to an insulating substrate by a screen printing method. In order to obtain a semiconductive layer having mechanical strength and chemical stability, a certain thickness is required. By obtaining a semiconductive layer by a screen printing method, it is possible to obtain a semiconductive layer that is thick to some extent of about 10 to 50 μm. Further, it is possible to easily avoid the provision of the semiconductive layer at the end portion of the insulating substrate as described in claim 20 by a screen printing method capable of printing a free pattern depending on the screen. Is possible.

  The edge part of a semiconductive layer points out the part of a crack at the time of apply | coating to an insulating board | substrate. That is, if the coating is applied up to the end surface of the insulating substrate, the end of the semiconductive layer means the end of the semiconductive electrode plate itself. Here, depending on the voltage and the distance between the electrode plates, corona discharge is generated from the end of the semiconductive layer of the electrode plate to which a high voltage is applied toward the semiconductive layer of the other electrode plate. Depending on the magnitude of the corona discharge, a large amount of ozone is generated, and the surface potential of the semiconductive layer is lowered. A method of positively utilizing this corona discharge has been devised separately, but the corona discharge generated at the end of the semiconductive layer is suppressed considering only the stabilization of performance as the collection part of the dust collector and the suppression of ozone. You had better. As a specific method for suppressing, the end of the semiconductive layer provided on the electrode plate on the side to which the high voltage is applied among the dust repellent electrode plate and the dust collecting electrode plate as described in claim 18 is used. The method of providing in the position which is not pinched | interposed with the semiconductive layer of the other electrode plate is mentioned. For example, under the condition that a high voltage is applied to the dust repellent electrode plate and 0 kV is applied to the dust collecting electrode plate, the end of the semiconductive layer of the dust collecting electrode plate is provided inside the dust collecting device, By positioning the end portion of the conductive layer as far as possible, the end portion of the semiconductive layer of the dust repellent electrode plate can be prevented from being sandwiched between the semiconductive layers of the dust collecting electrode plate. By doing so, the structure is such that the semiconductive layer of the dust collecting electrode plate to which 0 V is applied is not seen when viewed from the end of the semiconductive layer of the dust repellent electrode plate to which the high voltage is applied, and the high voltage is applied. It is possible to suppress corona discharge that may occur from the end of the semiconductive layer of the dust repellent electrode plate.

  In addition, as another method for suppressing corona discharge, as described in claim 19, at least the end of the semiconductive layer of the electrode plate on the side to which a high voltage is applied among the dust repellent electrode plate and the dust collecting electrode plate The method of coat | covering a part with an insulator is mentioned. The end of the semiconductive layer on the electrode plate to which a high voltage is applied is covered with an insulator such as an insulating film or a caulking agent so that it does not come into contact with air. Further, in the case where an object grounded to the outside of the dust collector and having a voltage of 0 V, in particular, a conductor is present, in order to suppress corona discharge generated toward the object, as described in claim 20, Of the dust repellent electrode plate and the dust collecting electrode plate, it is effective that at least the electrode plate to which a high voltage is applied has a structure in which a semiconductive layer is not provided at the end of the insulating substrate. By doing in this way, it becomes possible to set it as the structure where the edge part of the semiconductive layer of the electrode plate to which a high voltage is applied is not exposed with respect to the exterior of a dust collector.

  Further, the semiconductive electrode plate is provided with a through hole. Since the dust repellent electrode plate and the dust collecting electrode plate are alternately stacked in the dust collecting part, in order to provide a uniform electric field between the dust repellent electrode plate and the dust collecting electrode plate, The charge on the back should have a similar distribution. By providing a through hole in the semiconductive electrode plate, it is possible to apply a uniform charge to both the front and back surfaces of the semiconductive electrode plate through the wall surface of the through hole, and between the dust repellent electrode plate and the dust collecting electrode plate. A uniform electric field can be easily provided.

  Further, the wall surface of the through hole is made conductive. By imparting conductivity to the wall surface of the through hole, it is possible to more reliably make the distribution of electric charges given to the front and back surfaces of the semiconductive electrode plate the same.

  Further, the insulating substrate is a resin plate in which a resin material is filled with short glass fibers and mica and extruded and subjected to a heat lamination press. In order to support and fix each electrode plate without bridging the surfaces with a spacer or the like, it is necessary that the electrode plate does not bend greatly and does not have a large warp from the beginning. For this purpose, the electrode plate itself needs to have high strength and flatness. Resin material is filled with short glass fibers and mica and subjected to heat lamination press after extrusion molding to obtain a resin plate having high strength and high flatness. By using such a resin plate as an electrode plate, an electrode plate Can be suppressed.

  Also, both the dust repellent electrode plate and the dust collecting electrode plate are semiconductive electrode plates, and a conductive pattern is provided so as not to overlap the surface of the semiconductive layer or the surface of the insulating substrate in the semiconductive electrode plate when viewed from the stacking direction. Different voltages are applied to the conductive patterns of the dust repellent electrode plate and the dust collecting electrode plate, respectively. The electric charge is supplied from the terminal of the high-voltage power supply, but the electric charge is supplied more quickly as the position is closer to the terminal. By providing a conductive pattern on the semiconductive electrode plate and applying a voltage to the conductive pattern with a high-voltage power supply, it is possible to quickly and uniformly distribute charges on the semiconductive layer. It is possible to provide a uniform electric field in the space provided between the dust repulsion electrode plate and the dust collection electrode plate by the uniformly distributed charge, and it is possible to further improve the dust collection performance.

  In addition, the conductive pattern is provided in the shape of a fish bone. Specifically, one conductive pattern is provided, and a plurality of conductive patterns are provided in the shape of a fish bone so as to be orthogonal thereto, thereby forming the conductive pattern in the shape of a fish bone. Since the conductive pattern is provided to cover the entire surface of each electrode plate in the shape of a fish bone, a uniform charge can be quickly supplied to each surface of the dust repellent electrode plate and the dust collecting electrode plate This makes it possible to further improve the dust collection performance. Further, in order to prevent sparks caused by the conductive patterns provided on the respective electrode plates, it is necessary to ensure a certain space insulation distance. Therefore, the fish-bone-like conductive patterns provided on the dust repellent electrode plate and the dust collecting electrode plate are provided so as not to overlap when viewed from the stacking direction.

  Further, the distance between the conductive patterns provided on each of the dust repellent electrode plate and the dust collecting electrode plate is 15 mm or more. Generally, the withstand voltage of air is 1 kV / mm. The spark generation conditions vary depending on the potential difference between the dust repulsion electrode plate and the dust collection electrode plate. However, in the condition of 6 to 10 kV, which is often used as the potential difference, sparks are hardly generated if the space insulation distance is 15 mm or more. Sparks can be prevented by setting the distance between the conductive patterns provided on the repulsive electrode plate and the dust collecting electrode plate to 15 mm or more.

  In addition, a charging unit for charging the dust is provided on the upstream side of the dust collecting unit. For example, it is possible to obtain a high dust collecting action by the electric field of the dust collecting part by providing a charged part on the upstream side of the dust collecting part by attaching ions accelerated by corona discharge to the dust to make charged dust. . As a specific structure of the charging portion, a needle-like electrode is used as a discharging electrode of the charging portion as described in claim 28, and the needle-like electrode is provided horizontally with respect to the ventilation direction so as to sandwich the needle-like electrode. The thing provided horizontally with respect to the ventilation direction can be mentioned. By applying a high voltage to the needle electrode and applying 0 kV to the charged portion counter electrode plate, an uneven electric field is formed in the vicinity of the needle electrode. Corona discharge is generated in the vicinity of the tip of the needle electrode, and accelerated ions are released from the vicinity of the tip of the needle electrode and diffuse toward the charged portion counter electrode plate. Here, the ion diffusion region is formed over a wide range so as to draw a parabola from the tip of the needle electrode toward the charged portion counter electrode plate. Since the needle-like electrode is provided horizontally with respect to the ventilation direction, dust in the air can pass through an ion diffusion region provided in a wide range, and the dust can be reliably charged. Therefore, the dust collection performance of the dust collection device can be increased.

  Further, the needle-like electrode is a both-ends needle-like electrode with both ends sharpened. By sharpening both ends of the needle-like electrode and sandwiching both ends between the charged portion counter electrode plates, the ion diffusion region is doubled. Therefore, dust can be more reliably charged, and the dust collection performance of the dust collector can be further improved.

  In addition, a resistor is provided between the needle electrode and the high voltage power source. When a physical force is applied to a needle electrode and it is damaged, and the distance from the charged part counter electrode plate becomes small, a spark may occur between the needle electrode and the charged part counter electrode plate There is. By providing a resistor between the needle electrode and the high-voltage power supply, when the distance between the needle electrode and the charged portion counter electrode plate becomes small, the discharge current flowing from the needle tip increases and at the same time the voltage drop due to the resistor Increases, and the voltage of the needle electrode decreases. For this reason, even when the distance between the needle-shaped electrode and the charged portion counter electrode plate is reduced, it is possible to prevent a spark that may occur between the needle-shaped electrode and the charged portion counter electrode plate. At this time, if the number of needle tips of the needle electrodes connected to the resistor increases, the voltage drop increases from the beginning, resulting in a significant reduction in the discharge current of the needle electrodes and high dust collection performance. It cannot be secured. As described in claim 31, by setting the number of tips of the needle electrodes connected to the resistor to 1 or more and 6 or less, it is possible to obtain a discharge current of a certain level or more from the needle electrodes and ensure high dust collection performance. It becomes possible.

  Further, the resistance value of the resistor is 20 MΩ or more and 200 MΩ or less. If the value of the resistor provided between the high-voltage power supply and the needle electrode is too large, the voltage drop of the needle electrode becomes too large, resulting in a significant decrease in the discharge current of the needle electrode and high dust collection. Performance cannot be secured. By setting the resistance value of the resistor to 20 MΩ or more and 200 MΩ or less, it is possible to obtain a discharge current of a certain level or more from the needle-like electrode and ensure high dust collection performance.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Incidentally, these embodiments are merely examples, and the present invention is not limited to these embodiments.

(Embodiment 1)
The perspective view of the dust collection part 4 which laminated | stacked the dust repulsion electrode plate 2 and the dust collection electrode plate 3 which provided the semiconductive layer 1 which has the surface resistivity of 10 7-11th power / square in a dust collector. Is shown in FIG. 1, and a front view is shown in FIG. Incidentally, in FIG. 2, the frame 12 is shown as having a box shape, but in order to make the drawing easier to understand, only the portions on both sides where the insulator 13 is provided are shown in FIG.

  As shown in FIGS. 1 and 2, the dust repellent electrode plate 2 and the dust collecting electrode plate 3 are provided with a current-carrying through hole 5 and a space forming through hole 6 while sandwiching a cylindrical spacer 7 as shown in FIG. The shaft 8 is fixed while being spaced apart by inserting the shaft 8. The cylindrical spacer 7 and the shaft 8 are made of a conductive material such as metal, and are connected to the semiconductive layer 1 provided on each of the dust repellent electrode plate 2 and the dust collecting electrode plate 3 by connecting a high voltage power source 9. Different voltages, for example, −8 kV can be applied to the semiconductive layer 1 of the dust repellent electrode plate, and 0 kV can be applied to the semiconductive layer 1 of the dust collecting electrode plate. Therefore, an electric field is formed in the space 10 provided between the dust repellent electrode plate 2 and the dust collecting electrode plate 3. Air is introduced into the dust collecting unit 4 in the direction indicated by the ventilation direction 11, and charged dust, for example, negatively charged in the air passes through the space 10. Then, the charged dust is subjected to the Coulomb force from the electric field provided in the space 10 and adheres to the dust collecting electrode plate 3 and is collected. Here again, the dust repellent electrode plate 2 and the dust collecting electrode plate 3 are so-called semiconductive electrode plates in which a semiconductive layer 1 having a surface resistivity of 10 7-11 Ω / □ is provided on the surface. It has become. When the surface is conductive, sparks are generated because charge transfer on the surface occurs freely and rapidly, but charge transfer does not occur rapidly because the surface is semiconductive. Therefore, sparking can be prevented. Further, the dust repellent electrode plate 2 is supported by the insulator 13 provided outside the frame 12 so that the surfaces of the dust repellent electrode plate 2 and the dust collecting electrode plate 3 do not contact each other. That is, the surface potential does not decrease when the surfaces come into contact with each other, and a uniform and strong electric field is always formed in the space 10, so that high dust collection performance can be obtained while preventing sparks. It has become.

  Here, the structure of the dust repellent electrode plate 2 will be described with reference to FIGS. 4 and 5. FIG. Incidentally, the structure of the dust collecting electrode plate 3 is substantially the same as that of the dust repellent electrode plate 2, and the only significant difference is the positions of the energizing through hole 5 and the space forming through hole 6. As shown in FIG. 4, the dust repellent electrode plate 2 is provided with the semiconductive layer 1 on the surface of the insulating substrate 14, and at the same time, the energizing through hole 5 and the space forming through hole 6 are provided. The current-carrying through hole 5 is sized so that the shaft 8 just enters and comes into contact with the cylindrical spacer 7, and is fixed and energized by the contact point with the cylindrical spacer 7. Further, the space forming through hole 6 has such a size that the spatial distance from the cylindrical spacer 7 to which the dust collecting electrode plate 3 is fixed and energized is 15 mm or more as a guide. For example, if the outer diameter of the cylindrical spacer 7 is 14 mm, the diameter of the space forming through-hole 6 is 44 mm or more. If the potential difference from the dust collection electrode plate 3 is about −10 kV, the dust collection electrode plate 3 is fixed. It has a structure that does not generate sparks with the cylindrical spacer 7. Further, as a method for providing the semiconductive layer 1 on the surface of the insulating substrate 14, a semiconductive paint having a coating surface of 10 7 to the 11th power Ω / □ is applied and dried, or 10 7 to the 11th power. Examples thereof include a method of attaching a film having a volume resistivity of Ω · cm to the surface of an insulating substrate. The cylindrical spacer 7 is in contact with the shaft 8 connected to the high-voltage power source 9, and a charge corresponding to the applied voltage is supplied to the semiconductive layer 1 from the contact portion with the cylindrical spacer 7 around the current-carrying through hole 5. The Since the semiconductive layer 1 has a surface resistivity of 10 7-11 Ω / □, it has a function of suppressing rapid charge movement while uniformly distributing charges corresponding to the applied voltage. . Therefore, even if a state that becomes the base point of the spark is formed at a certain place such as when large dust adheres, the electric charge does not move abruptly, so that the generation of the spark can be prevented. That is, it is possible to prevent a spark while obtaining a high dust collection performance by distributing a charge corresponding to the applied voltage to form a uniform electric field in the space 10. FIG. 5 shows a dust repellent electrode plate provided with a plurality of small charge equalization through holes 15. The wall surface of the charge equalizing through-hole 15 has a semiconductive property such as a surface resistivity of 10 7 to 11th power Ω / □ or a conductivity of 10 1 to 4th power Ω / □, and a dust repellent electrode It has the function of making the charge distribution in the semiconductive layer 1 provided on the front and back of the plate 2 the same. Even if a portion where the contact between the cylindrical spacer 7 and the current-carrying through hole 5 is deteriorated is generated, if the contact of the other portion is sufficient, the charge distribution of the front and back semiconductive layers 1 is made the same throughout that portion, and the space 10 It is possible to obtain a uniform electric field at.

  In addition, although it demonstrated by the structure using the semiconductive electrode plate which provided the semiconductive layer 1 on the surface of the insulating board | substrate 14 as the dust repulsion electrode plate 2 and the dust collection electrode plate 3, originally the surface is 10-7. Even when a semiconductive electrode plate made of a material of 11 11 Ω / □ is used as the dust repulsion electrode plate 2 and the dust collection electrode plate 3, it is possible to obtain high dust collection performance while preventing sparks in the same manner. is there.

(Embodiment 2)
The verification results of the semiconductive layer 1 obtained by applying a screen printing ink composed of a semiconductive material, resin, and solvent to the resin insulating substrate 14 by a screen printing method and drying are shown below. Here, antimony-doped tin oxide-added titanium oxide having spherical and needle shapes was used as the semiconductive material in the ink, and a thermoplastic polyester resin was used as the resin. Also, when creating a semiconductive layer, a polyisocyanate-based molecular crosslinking agent is added to the ink at a certain ratio immediately before printing in order to polymerize the thermoplastic polyester resin as a binder component and ensure the strength as a binder. It is added. The thickness of the semiconductive layer 1 obtained by the screen printing method was about 10 μm. Table 1 shows the results of the study on the relationship between the shape of the semiconductive material and the surface resistivity of the semiconductive layer. The spherical semiconductive material has a particle diameter of about 0.3 μm, and the needle-shaped semiconductive material has a thickness of about 0.2 μm and a length of about 3 μm. Table 1 shows the surface resistivity of the semiconductive layer prepared using spherical and needle-shaped semiconductive materials.

  As shown in Table 1, in order to obtain a surface resistivity of 10 9 to 10 10 Ω / □, the weight ratio of the semiconductive material in the semiconductive layer 1 is 60% spherical and 22% needle-shaped. %. From this result, it was found that the semiconductivity can be obtained with a smaller amount of the needle shape than the spherical shape. This is because the needle shape is more likely to come into contact with each other because the particles overlap each other.

  Next, the relationship between surface resistivity and surface potential was investigated. As shown in FIG. 6, the 90 mm square semiconductive layer 1 was provided on the insulating substrate 14, and one corner and a terminal of the high voltage power source 9 were brought into contact with each other to apply −3 kV. Then, the surface potential of the semiconductive layer 1 is measured by a non-contact type surface potential meter 16 (MODEL 279 manufactured by Monroe Electronics) previously provided in the central portion 17 of the semiconductive layer 1, and the time until it reaches -3 kV is determined. Measured. The results are shown in Table 2.

  From this result, it is found that if the surface resistivity is 10 11 Ω / □ or less, it reaches −3 kV within 30 seconds, but if it is more than that, it takes 100 seconds or more to reach −3 kV. It was. That is, it was found that the surface resistivity of the semiconductive layer 1 needs to be 10 11 Ω / □ or less in order to obtain a quick response that can quickly increase the voltage supplied from the high-voltage power supply.

  Next, as shown in FIG. 7, an inner cylindrical electrode 18 having a diameter of 50 mm and a ring-shaped outer cylindrical electrode 19 having an inner diameter of 70 mm are placed on the semiconductive layer 1, the inner cylindrical electrode 18 is grounded to 0 V, and the outer A voltage of 1 to 8 kV was applied to the tube electrode 19. The current flowing through both electrodes was measured to calculate the surface resistivity. Incidentally, the semiconductive material used for producing the semiconductive layer 1 is needle-shaped antimony-doped tin oxide-added titanium oxide, and two types of aluminum-doped zinc oxide having a particle diameter of about 0.2 μm for comparison, and the surface resistivity is 1 kV. At the time of application, the test was performed with six types of semiconductive layers 1 in total of about 10, 12, 10 and 7th power Ω / □. The results are shown in Table 3.

  As shown in Table 3, the semiconductive layer 1 using antimony-doped tin oxide-added titanium oxide shows no significant change in surface resistivity even when the voltage is changed to 1, 4 and 8 kV. However, in the sample having a surface resistivity of 5 × 10 7 Ω / □ at 1 kV, sparking occurred only once. After that, when the surface was observed, no change in state was observed, but from the viewpoint of preventing sparks and ensuring safety, sparks may occur when the surface resistivity is 10 7 Ω / □ or less. In consideration of the fact that an electric current flows and heat is generated when there is an abnormality in contact with the dust collecting electrode plate, the result is that at least 10 7 Ω / □ or more is desirable. However, in the semiconductive layer 1 using aluminum-doped zinc oxide, the surface resistivity decreases as the voltage is increased to 1, 4, and 8 kV, and the sample has a surface resistivity of 10 to the 8th power and 10th power / Ω / □ at 1 kV. In the case of sparks, a spark occurred and the power was turned on. When the surface was observed after the test, a single burn was generated, and it was confirmed that the insulating substrate 14 was carbonized and conducted. Thus, it can be seen that depending on the semiconductive material, the surface resistivity changes in the conduction direction as the voltage increases, and such changes do not occur significantly with antimony-doped tin oxide-added titanium oxide. It was found that a predetermined surface resistivity can be obtained stably.

  Further, in order to investigate the effect of the polyisocyanate-based molecular cross-linking agent, when immersed in a water-soluble oil mixed with a surfactant and mineral oil for 1 month, the semiconductive layer 1 prepared by adding the molecular cross-linking agent has an appearance, Although there was no change in the surface resistivity, the semiconductive layer 1 prepared without the addition of the molecular cross-linking agent developed a color fading indicating the loss of the white semiconductive material. 10 8 Ω / □ increased to 10 12 Ω / □ or more. From this result, it was found that the addition of a molecular crosslinking agent can prevent the deterioration of the resin and improve the fixing performance of the semiconductive material.

(Embodiment 3)
A semiconductive electrode plate in which the semiconductive layer 1 is provided on the surface of the insulating substrate 14 is used as the dust repellent electrode plate 2 and the dust collecting electrode plate 3, and the end 20 of the semiconductive layer of the dust repellent electrode plate is used as the dust collecting electrode plate. FIG. 8 shows a stack diagram of a set of electrode plates provided at positions not sandwiched by three semiconductive layers 1, and a dust repellent electrode in which the end 20 of the semiconductive layer of the dust repellent electrode plate is covered with an insulating sheet 21. The plate is shown in FIG. Incidentally, the embodiment is shown under the condition that a high voltage is applied to the dust repellent electrode plate 2 and 0 V is applied to the dust collecting electrode plate 3. As shown in FIG. 8, the end 20 of the semiconductive layer of the dust repellent electrode plate is provided at a position not surrounded by the semiconductive layer 1 of the dust collecting electrode plate 3. Thus, no corona discharge occurs from the dust collecting electrode plate 3 toward the semiconductive layer 1. At the same time, the end 20 of the semiconductive layer of the dust repellent electrode plate is applied by screen printing so as not to reach the end of the insulating substrate. By doing so, the end 20 of the semiconductive layer of the dust repellent electrode plate is not exposed toward the outside of the dust collector, and even if a grounded object exists outside the dust collector, the corona is directed toward it. The structure is such that no discharge occurs.

  Further, as shown in FIG. 9, since the end 20 of the semiconductive layer of the dust repellent electrode plate is covered with the insulating sheet 21 and does not come into direct contact with air, corona discharge is caused from the end 20 of the semiconductive layer of the dust repellent electrode plate. It has a structure that does not occur. As the insulating sheet 21, an insulating resin film or tape can be used. Further, the same effect can be obtained even by means such as coating with a silicone caulking agent instead of the insulating sheet 21 if the end 20 of the semiconductive layer of the dust repellent electrode plate is covered with an insulator. .

(Embodiment 4)
A dust repellent electrode plate 2 having a fish bone-like conductive pattern 22 and having a semiconductive layer 1 on its surface is shown in FIG. 10, and a fish bone-like conductive pattern 22 is provided and having a semiconductive layer 1 on its surface. The dust collecting electrode plate 3 is shown in FIG. As shown in FIGS. 10 and 11, the conductive pattern 22 is also provided in the portion in contact with the cylindrical spacer 7 around the current-carrying through hole 5, so that the supply of charges from the cylindrical spacer 7 can be made more reliable. It has become. By providing the conductive pattern 22, it becomes possible to supply charges to the semiconductive layer 1 on the surface more uniformly and quickly. The same effect can be obtained whether the conductive pattern 22 is provided on either the surface of the insulating substrate 14 or the surface of the semiconductive layer 1. Examples of the method for providing the conductive pattern 22 include the following. A conductive film made of copper or the like is provided on the surface, and a transparent film on which a conductive pattern is printed is superimposed on an insulating substrate 14 coated with a photosensitive agent called a resist on the surface, exposed to ultraviolet rays, and then exposed to a developer. The conductive agent 22 is removed from the exposed portion of light and then immersed in an etching agent to dissolve the conductive film under the removed photosensitive agent, so that the conductive pattern 22 is formed only on the portion not exposed to the light. Or a method of printing a conductive ink made of silver, carbon or the like on the insulating substrate 14 or the semiconductive layer 1 by screen printing and drying to obtain a conductive pattern. The conductive patterns 22 provided on the dust repellent electrode plate 2 and the dust collecting electrode plate 3 are provided at positions where they do not overlap when viewed from the stacking direction. This is because different voltages are applied to the conductive patterns, and since they are conductive, a certain spatial distance is taken to prevent sparks. As a guide, a spatial distance of 15 mm or more is taken at a potential difference of about 10 kV. By doing so, it is possible to prevent sparks between conductive patterns to which different voltages are applied.

(Embodiment 5)
FIGS. 12 and 13 show a charging unit 25 provided with needle-like electrodes 23 with both ends pointed horizontally and the charging unit counter electrode plate 24 provided horizontally with respect to the ventilation direction 11 so as to sandwich the needle-like electrode 23 therebetween. Here, the charging unit 25 has a structure similar to that of the dust collecting unit 4, but the needle-like electrode 23 is fixed to a discharge substrate 26 having a current-carrying through hole 5, and the discharge substrate 26 has a shaft while sandwiching the cylindrical spacer 7. 8 and fixed to the frame 12 by a lever 13. Similarly, the charged portion counter electrode plate 24 is fixed by the shaft 8 with the cylindrical spacer 7 interposed therebetween, and the discharge substrate 26 and the charged portion counter electrode plate 24 are insulated by the insulator 13. In such a structure, when a high potential difference is applied between the needle-like electrode 23 and the charged portion counter electrode plate 24, discharge occurs at the tip of the needle-like electrode 23, and ions are generated near the tip. The acicular electrode 23 accelerates ions so as to diffuse widely toward the position of the charged portion counter electrode plate 24, particularly in the direction in which the tip of the acicular electrode faces. Therefore, the probability that the accelerated ion contacts the dust in the air introduced from the ventilation direction 11 increases, and as a result, the dust can be reliably charged. FIG. 14 shows the arrangement of the charging unit 25 and the dust collecting unit 4 in the dust collecting device. As shown in FIG. 11, the dust collection unit 4 is arranged on the downstream side of the charging unit 25, and the dust collection performance is enhanced because the dust that is positively charged by the charging unit 25 is collected by the dust collection unit 4. An example of the discharge substrate 26 is shown in FIG. The discharge substrate 26 shown in FIG. 15 has a structure in which a plurality of needle-like electrodes 23 are provided on the insulating substrate 14, and the conductive pattern 22 is connected so as to connect the periphery of the current-carrying through hole 5 and the needle-like electrode 23. Is provided. The cylindrical spacer 7 in contact with the shaft 8 to which the high voltage power supply 9 is connected and the conductive pattern 22 are in contact with each other, so that a high voltage of, for example, −10 kV is applied to the needle electrode 23. The charged portion counter electrode plate 24 is made of a conductive material such as metal, and is connected to the high voltage power source 9 to apply a voltage of, for example, 0 kV. Here, in the conductive pattern 22 of the discharge substrate 26, a resistor 27 is provided in the middle of a conduction path between the needle-like electrode 23 and the current-carrying through hole 5. By providing the resistor 27, for example, even if the needle-like electrode 23 is bent and approaches the charged portion counter electrode plate 24 so that a spark is generated, the discharge current increases and the voltage drop becomes large due to the action of the needle-like electrode 23. As a result, the distance at which the voltage decreases and the spark starts, that is, the so-called spark distance can be reduced. As a result, it is possible to improve safety and to improve the performance of charging dust by setting the distance between the needle-like electrode 23 and the charging portion counter electrode plate 24 to be small.

  Here, it is desirable to provide the resistors 27 so that the number of tips of the needle-like electrodes 23 is 6 or less per one. If the number of needle-shaped electrodes 23 connected is too large, the discharge current passing through one resistor 27 increases, and the voltage drop becomes excessively large. When the voltage drop becomes excessively large, the degree of discharge that occurs at the tip of the needle electrode 23 decreases, and the amount of ions that are generated and accelerated decreases. As a result, the dust collection performance is lowered. The resistance value of the resistor 27 is preferably in the range of 20 MΩ to 200 MΩ. If this is less than 20 MΩ, the spark distance will not be so small compared to the case without a resistor, and if it is greater than 200 MΩ, a large voltage drop will occur with a small discharge current, resulting in a needle electrode. This is because the discharge to be performed becomes small, the amount of ions becomes small, and high dust collection performance cannot be obtained. Here, the experimental apparatus shown in FIG. 16 was assembled and the change in the spark distance was verified. That is, a metal plate 28 is installed as the charged portion counter electrode plate 24, and a needle-like electrode 23 is provided on the metal plate 28 so as to be perpendicular to the metal plate 28. The needle-like electrode 23 has −8 kV and the metal plate 28 has 0 kV. The tip of the needle electrode 23 was brought close to the metal plate 28 while applying a voltage. At this time, a resistor 27 having an arbitrary resistance value was connected in series between the needle electrode 23 and the high-voltage power supply 9. The discharge current when the spark generation distance, that is, the spark distance and the distance between the tip of the needle electrode 23 and the metal plate 28 was 15 mm was measured by an ammeter 29. The results are shown in Table 1.

  When the high voltage power supply 9 and the needle electrode 23 were directly connected without connecting the resistor 27, the spark distance was 5.0 mm and the discharge current was 20.4 μA. In contrast, at 10 MΩ, the spark distance is 4.0 mm and the discharge current is 17.2 μA, at 20 MΩ, the spark distance is 3.0 mm and the discharge current is 15.0 μA, and at 40 MΩ, the spark distance is 2.0 mm and the discharge current is 14.0 μA. At 50 MΩ, the spark distance is 1.2 mm and the discharge current is 13.6 μA. At 100 MΩ, the spark distance is 0.8 mm and the discharge current is 11.5 μA. At 200 MΩ, the spark distance is 0.6 mm and the discharge current is 8.7 μA and 300 MΩ. Then, the spark distance was 0.5 mm and the discharge current was 7.0 μA. Thus, if the resistance value of the resistor 27 is increased, the spark distance is decreased, but the discharge current is also decreased. This indicates that the higher the resistance value of the resistor 27, the greater the degree of voltage drop in the needle electrode 23 caused by the resistor 27. In this verification, the spark distance was not so small at 10 MΩ, and the discharge current was too small at 300 MΩ or more. In order to obtain the minimum necessary discharge current while minimizing the spark distance, the resistance value of the resistor 27 needs to be in an optimum range. 20 MΩ to 200 MΩ is the optimum range of resistance values according to this verification, and more specifically, 50 MΩ or more and 100 MΩ or less is the optimum range when a discharge current of 1/2 or more is desired while reducing the spark distance to around 1 mm. I understood it.

  In addition, in order to grasp how many tips of the needle-like electrode 23 are connected to one resistor 27 to ensure the minimum necessary discharge current while reducing the spark distance, as shown in FIG. A device in which the needle-like electrode 23 was connected to the resistor 27 having a resistance of 50 MΩ so that the tips were 1, 2, 4, 6, 8, and 10 was created and verified. The spark distance when only one tip of the needle electrode 23 is brought close to the metal plate 28 with −8 kV applied to the needle electrode 23 and 0 kV applied to the metal plate 28, and the tip of the needle electrode 23 and the metal plate 28. And the discharge current per one tip of the needle-like electrode 23 when the distance to is 15 mm. The results are shown in Table 2.

  With one tip connected to the resistor 27, a discharge current of 13.6 μA with a spark distance of 1.2 mm, with two tips, a discharge distance of 11.1 μA with a spark distance of 1.2 mm, and with four tips, a spark distance of 1.2 mm Discharge current is 9.3 μA, 6 tips have a spark distance of 1.2 mm and discharge current is 7.3 μA, 8 tips has a spark distance of 1.2 mm and discharge current is 6.0 μA, and 10 tips have a spark distance of 1. The discharge current was 5.0 μA at 2 mm. Although the spark distance hardly changes even if the number of connected tips is changed, the discharge current when the distance between the needle electrode 23 and the metal plate 28 is 15 mm increases the discharge per tip as the number of connected tips increases. The current becomes smaller. This is because as the number of connected tips increases, the current flowing through the resistor 27 increases, the voltage drop increases, and the voltage of the needle electrode 23 decreases. Here, when the number of connected tips is 6 or less, it is possible to secure a discharge current of 1/2 or more when the number of connected tips is 6 or less. Therefore, a high discharge current cannot be secured. That is, it was found that the number of needle-shaped electrodes connected to one resistor is preferably 6 or less.

  In addition, the needle-like electrode 23 of the present invention means that the tip has a shape that is thin enough to cause discharge. For example, the diameter of the waist is 0.5 mm or less, and the tip is sufficiently thin and can be discharged. If it is a simple shape, it is not always necessary to sharpen the tip.

  The dust collector of the present invention is capable of preventing sparks in both the dust collecting part and the charging part while obtaining high dust collecting performance, so that a dust collector that requires high dust collecting performance and safety at the same time, for example, a factory It is useful as a dust collection device to be installed in oil mist dust collectors, household air purifiers, or air supply type ventilation fans.

The perspective block diagram which shows the dust collection part of Embodiment 1 of this invention Front configuration diagram showing the dust collector Configuration diagram showing the cylindrical spacer Configuration diagram showing the dust repellent electrode plate Configuration diagram showing dust repulsion electrode plate with the same charge equalization through hole The figure which shows the experimental apparatus used for the verification as described in Embodiment 2. Diagram showing the experimental equipment used for the verification The block diagram which shows one set of the dust repulsion electrode plate and dust collection electrode plate as described in Embodiment 3 Configuration diagram showing dust repellent electrode plate with end of semiconductive layer covered with insulating sheet The block diagram which shows the dust repulsion electrode plate as described in Embodiment 4 Configuration diagram showing the dust collection electrode plate The perspective block diagram which shows the charge part as described in Embodiment 5. Front configuration diagram showing the same charging unit Configuration diagram showing the same discharge substrate The figure which shows the arrangement | sequence of the charge part and dust collection part of the dust collector Diagram showing the experimental equipment used for the verification Diagram showing the experimental equipment used for the verification The block diagram which shows the dust collection part of patent document 1 Configuration diagram showing collector electrode plate described in Patent Document 2 The figure which shows the AB cross section in FIG. 14 of the collector electrode plate The figure which shows the dust collection part which laminates and forms the same collector electrode plate

DESCRIPTION OF SYMBOLS 1 Semiconductive layer 2 Dust repulsion electrode plate 3 Dust collection electrode plate 4 Dust collection part 5 Current supply through-hole 6 Space formation through-hole 7 Cylindrical spacer 8 Shaft 9 High voltage power supply 10 Space 11 Ventilation direction 12 Frame 13 Insulator 14 Insulating substrate 15 Charge uniformizing through hole 16 Surface potential meter 17 Central portion 18 Inner cylinder electrode 19 Outer cylinder electrode 20 End of semiconductive layer of dust repellent electrode plate 21 Insulating sheet 22 Conductive pattern 23 Needle electrode 24 Charging portion counter electrode plate 25 Charging Part 26 discharge board 27 resistor 28 metal plate 29 ammeter

Claims (32)

In a dust collector equipped with a dust collecting part in which dust repellent electrode plates and dust collecting electrode plates are alternately stacked and fixed by a frame, at least one of the dust repellent electrode plate and the dust collecting electrode plate is semiconductive or insulated And a semi-conductive electrode plate having a surface resistivity of 10 7 to 10 Ω / □, and a dust repellent electrode plate and a dust collecting electrode plate are provided outside the frame. Dust collector characterized by being connected with a coconut shell. In a dust collector equipped with a dust collecting part in which dust repellent electrode plates and dust collecting electrode plates are alternately stacked and fixed by a frame, at least one of the dust repellent electrode plate and the dust collecting electrode plate is semiconductive or insulated And a semiconductive electrode plate having a surface resistivity of 10 7-11 Ω / □, and a dust repellent electrode plate and a dust collecting electrode plate are provided outside the frame. Dust collector characterized by being connected with a coconut shell. A through-hole is provided in each of the dust repellent electrode plate and the dust collecting electrode plate, and the dust repellent electrode plate and the conductive cylindrical spacer are inserted in this order while the conductive shaft is inserted, and then the dust collecting electrode plate and the conductive cylindrical spacer are arranged in this order. The dust collector according to claim 1, wherein the dust collector is provided. 4. The dust collector according to claim 1 or 3, wherein the semiconductive electrode plate is provided with a semiconductive layer having a surface resistivity of 10 7 to 10 10 Ω / □ on the surface of the insulating substrate. . 4. The dust collector according to claim 2, wherein the semiconductive electrode plate is provided with a semiconductive layer having a surface resistivity of 10 7-11 Ω / □ on the surface of the insulating substrate. . 5. A dust collector according to claim 4, wherein a resin film having a volume resistivity of 10 <7> to 10 <10> [Omega] .cm is provided on the surface of the insulating substrate as a semiconductive electrode plate. 6. A dust collector according to claim 5, wherein a semiconductive electrode plate is formed by providing a resin film having a volume resistivity of 10 <7> to 11 <11> [Omega] .cm on the surface of an insulating substrate. A semiconductive electrode plate is formed by applying a semiconductive paint having a coating surface of 10 7 to 10 Ω / □ on the surface of an insulating substrate and drying to provide a semiconductive layer. Item 5. A dust collector according to Item 4. A semiconductive electrode plate is obtained by applying a semiconductive paint having a coated surface of 10 7 to 11 to 11 / Ω / □ on the surface of an insulating substrate and drying to provide a semiconductive layer. Item 6. A dust collector according to Item 5. The dust collector according to claim 8 or 9, wherein the semiconductive paint includes a semiconductive material and a binder component for fixing the semiconductive material to the application surface. The dust collector according to claim 10, wherein the semiconductive material is an ion conductive polymer. The dust collector according to claim 10, wherein the semiconductive material is a semiconductive metal oxide. 13. The dust collector according to claim 12, wherein the metal oxide is tin oxide or tin oxide doped with antimony. 11. The dust collecting apparatus according to claim 10, wherein the semiconductive material is tin oxide or tin oxide doped with antimony added to carrier particles having a larger particle diameter. 15. The dust collector according to claim 14, wherein the carrier particles have a needle shape. The dust collector according to any one of claims 10 to 15, wherein a semiconductive coating material in which a binder component is a resin and a molecular crosslinking agent is added is used. The dust collector according to any one of claims 8 to 16, wherein a semiconductive layer is provided by applying a semiconductive paint to an insulating substrate by a screen printing method. Of the dust repellent electrode plate and the dust collecting electrode plate, the end of the semiconductive layer provided on the electrode plate on the side to which the high voltage is applied is provided at a position not sandwiched by the semiconductive layer of the other electrode plate. The dust collector according to claim 1, wherein 19. The end portion of the semiconductive layer of the electrode plate on at least a side to which a high voltage is applied is covered with an insulator among the dust repellent electrode plate and the dust collecting electrode plate. Dust collector. 20. The semiconductor substrate according to claim 1, wherein a semiconductive layer is not provided at an end portion of the insulating substrate in at least an electrode plate to which a high voltage is applied among the dust repellent electrode plate and the dust collecting electrode plate. The dust collector described in 1. 21. The dust collector according to claim 1, wherein a through hole is provided in the semiconductive electrode plate. The dust collector according to claim 21, wherein the wall surface of the through hole is made conductive. The dust collector according to any one of claims 4 to 22, wherein the insulating substrate is a resin plate in which a resin material is filled with short glass fibers and mica and extruded and subjected to a heat lamination press. Both the dust repellent electrode plate and the dust collecting electrode plate are semiconductive electrode plates, and a conductive pattern is provided on the semiconductive electrode plate so that it does not overlap the surface of the semiconductive layer or the insulating substrate when viewed from the stacking direction. The dust collector according to any one of claims 1 to 23, wherein different voltages are applied to the conductive patterns of the electrode plate and the dust collecting electrode plate, respectively. 25. The dust collector according to claim 24, wherein the conductive pattern is provided in the shape of a fish bone. 26. The dust collector according to claim 24, wherein a distance between the conductive patterns provided on each of the dust repellent electrode plate and the dust collecting electrode plate is 15 mm or more. 27. The dust collector according to claim 1, further comprising a charging unit that charges the dust upstream of the dust collecting unit. A needle-like electrode is used as a discharge electrode of the charging part, the needle-like electrode is provided horizontally with respect to the ventilation direction, and the charging part counter electrode plate is provided horizontally with respect to the ventilation direction so as to sandwich the needle-like electrode. The dust collector according to claim 27. 29. The dust collector according to claim 28, wherein the needle-like electrode is a both-end needle-like electrode having pointed ends. 30. The dust collector according to claim 28 or 29, wherein a resistor is provided between the needle electrode and the high voltage power source. 31. The dust collector according to claim 30, wherein the number of tips of the needle electrodes connected to the resistor is 1 or more and 6 or less. The dust collector according to claim 30 or 31, wherein the resistance value of the resistor is 20 MΩ or more and 200 MΩ or less.

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