JP2013202479A - Electric dust collector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric dust collector capable of maintaining corona discharge for a long period and maintaining high dust collection performance for a long time in the electric dust collector used for air cleaning.SOLUTION: All tips of discharge members 10 face the same direction, and a clearance between the tips of the discharge members 10 is set to be 15-20 mm. A clearance between the discharge member 10 and a ground electrode 7 is set to be 20 mm or less. When the discharge member 10 is projected onto a face of the ground electrode 7, an overlap between the discharge member 10 and the ground electrode 7 is set to be 5 mm or more, and the clearance between the discharge member 10 and the ground electrode 7 is set larger than the overlap between the discharge member 10 and the ground electrode 7. Thus, corona discharge is uniformly performed to efficiently charge dust, and a region preventing adhesion of dust is produced on the ground electrode 7, so as to obtain an electric dust collector capable of maintaining corona discharge for a long period and maintaining high dust collection performance for a long time.

Description

  The present invention relates to an electric dust collector for collecting dust in the air and cleaning the air.

  Conventionally, this kind of electrostatic precipitator is known as follows (for example, refer to Patent Document 1).

  Hereinafter, the electrostatic precipitator will be described with reference to FIG. 6 which is a configuration diagram showing a cross section of a conventional electrostatic precipitator.

  As shown in FIG. 6, the electrostatic precipitator 101 includes a planar ground electrode 105 in parallel with the air flow, and a discharge electrode 104 including a support 102 and a plurality of discharge members 103 in parallel therewith. ing.

  Then, a DC high voltage is supplied from the DC high voltage power source to the discharge electrode 104 to generate a corona discharge between the ground electrode 105 and the discharge electrode 104 to charge and collect dust in the air.

  The material of the ground electrode 105 is a metal such as steel, stainless steel, or aluminum. The discharge member 103 is usually made of steel or stainless steel, but may be made of a metal such as titanium, iridium, platinum, rhodium, tungsten, or an alloy thereof in consideration of corrosion and corrosion resistance.

  As the shape of the discharge member 103, as shown in FIG. 6, a shape in which both ends of the discharge member 103 protrude to both sides of the support 102, a shape in which the discharge member 103 has a wire shape, etc. are proposed. ing.

JP 59-59258 A

  In such a conventional electrostatic precipitator, the corona discharge generated between the discharge member and the ground electrode spreads both in the direction along the air flow direction and in the opposite direction, and lands on the ground electrode.

  Dust that has passed through the area where the discharge spreads is charged, but since an electric field is generated simultaneously with the corona discharge between the discharge member and the ground electrode, the charged dust is successively applied to the ground electrode. The ground electrode gradually gets dirty with dust.

  As the ground electrode becomes dirty, the surface state of the ground electrode changes, and it becomes difficult for corona discharge from the discharge member to occur, and the discharge becomes weaker. That is, since the ability to charge the dust is reduced, the dust collection performance is gradually reduced. Therefore, there has been a problem that it is necessary to frequently clean the electrostatic precipitator in order to remove dirt on the ground electrode and restore the dust collecting performance.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object thereof is to provide an electric dust collector capable of maintaining corona discharge for a long period of time and maintaining high dust collection performance for a long period of time. And

  In order to achieve this object, the present invention provides an electrostatic precipitator including a charging unit that charges dust in the air and a dust collection unit that collects charged dust. An electrode, a discharge electrode fixing member, a discharge electrode support member, a ground electrode, a ground electrode support member, and a frame, the discharge electrode comprising a needle-like discharge member and a discharge member support, Are fixed to the discharge member support so that the tips of the discharge members are all directed in the same direction and the interval between the tips of the discharge members is 15 to 20 mm, and the interval between the discharge member and the ground electrode is 20 mm or less. When the discharge member is projected on the surface of the ground electrode, the overlap between the discharge member and the ground electrode is 5 mm or more, and the interval between the discharge member and the ground electrode is larger than the overlap between the discharge member and the ground electrode. Electric dust collection Is obtained by a location, thereby it is to achieve the intended purpose.

  According to the present invention, in an electrostatic precipitator having a charging unit that charges dust in the air and a dust collection unit that collects charged dust, the charging unit includes a plurality of discharge electrodes, a discharge electrode fixing member, A discharge electrode support member, a ground electrode, a ground electrode support member, and a frame. The discharge electrode includes a needle-like discharge member and a discharge member support, and the tips of the discharge members are all directed in the same direction. The discharge member is fixed to the discharge member support so that the interval between the tips of the discharge member is 15 to 20 mm, the interval between the discharge member and the ground electrode is 20 mm or less, and the discharge member is placed on the surface of the ground electrode. By making the overlap between the discharge member and the ground electrode 5 mm or more when projected on the top, and making the interval between the discharge member and the ground electrode larger than the overlap between the discharge member and the ground electrode, Corona release from the discharge member Can be discharged uniformly without interfering with each other, and dust can be charged efficiently, and when viewed from the upstream direction of the air flow, corona discharge from the discharge member is applied to the ground electrode. High dust collection performance because it is possible to maintain corona discharge over a long period of time by creating a region where dust is less likely to adhere to the ground electrode by ensuring a sufficient area before the part that spreads and lands Can be obtained for a long time.

Configuration diagram of the electric dust collector of Embodiment 1 of the present invention Configuration view of the charging unit provided in the electrostatic precipitator from an angle Configuration view of the charging unit provided in the electric dust collector from the top The block diagram which shows the cross section of the electrification part with which the same electric dust collector is equipped Configuration diagram of the ground electrode provided in the electric dust collector Configuration diagram of conventional electrostatic precipitator

  The electrostatic precipitator according to claim 1 of the present invention is an electrostatic precipitator including a charging unit that charges dust in the air and a dust collecting unit that collects the charged dust. The charging unit includes a plurality of discharges. An electrode, a discharge electrode fixing member, a discharge electrode support member, a ground electrode, a ground electrode support member, and a frame, the discharge electrode comprising a needle-like discharge member and a discharge member support, Are fixed to the discharge member support so that the tips of the discharge members are all directed in the same direction and the interval between the tips of the discharge members is 15 to 20 mm, and the interval between the discharge member and the ground electrode is 20 mm or less. When the discharge member is projected on the surface of the ground electrode, the overlap between the discharge member and the ground electrode is 5 mm or more, and the interval between the discharge member and the ground electrode is larger than the overlap between the discharge member and the ground electrode. An electric dust collector That.

  By setting the interval between the tips of the discharge members to 15 to 20 mm, the corona discharge from each discharge member can be uniformly discharged without interfering, and dust can be efficiently charged. An electric dust collector having dust collecting performance can be obtained.

  Further, the distance between the discharge member and the ground electrode is set to 20 mm or less, and the overlap between the discharge member and the ground electrode when projected on the surface of the ground electrode is set to 5 mm or more. Is larger than the overlap between the discharge member and the ground electrode, so that when viewed from the direction of air flow, the corona discharge from the discharge member spreads with respect to the ground electrode and reaches the area before the landing. It is possible to maintain corona discharge over a long period of time by creating an area where dust is not easily adhered to the ground electrode, so an electric dust collector that can maintain high dust collection performance over a long period of time can be obtained. Can be obtained.

In the electrostatic precipitator according to claim 2 of the present invention, the ground electrode is provided with a resistor on the surface thereof, and the surface resistivity of the resistor is 10 ⁶ Ω / □ or more and less than 10 ¹⁰ Ω / □. The electrostatic precipitator according to claim 1, wherein:

In the region where the surface resistivity is less than 10 ⁶ Ω / □, spark discharge occurs and the dust is charged when the distance between the discharge electrode and the ground electrode becomes extremely small due to unintended deposits. As a result, the dust collection performance may be reduced. Also, in the region where the surface resistivity is 10 ¹⁰ Ω / □ or more, corona discharge is less likely to occur between the discharge electrode and the ground electrode, and the ability to charge dust is reduced, resulting in reduced dust collection performance. There is sex.

Therefore, by making the surface resistivity of the resistor provided on the surface of the ground electrode 10 ⁶ Ω / □ or more and less than 10 ¹⁰ Ω / □, corona discharge is generated while suppressing the occurrence of spark discharge. Therefore, it is possible to obtain an electric dust collector that does not deteriorate the dust collection performance due to spark discharge.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a configuration diagram of an electrostatic precipitator according to Embodiment 1 of the present invention.

  As shown in FIG. 1, the electrostatic precipitator 1 according to Embodiment 1 of the present invention arranges the dust collector 3 on the downstream side of the charging unit 2 along the flow of air (arrow in FIG. 1). It has become the composition. When dust-containing air flows into the charging unit 2, dust in the air is charged when passing through the corona discharge region generated by the charging unit 2.

  Subsequently, when air containing charged dust flows into the dust collector 3, the charged dust receives a Coulomb force by the electric field generated in the dust collector 3 and is collected on the electrode. Thereby, the air flowing out from the electrostatic precipitator 1 becomes clean.

  FIG. 2 is a configuration diagram in which the charging unit provided in the electrostatic precipitator according to Embodiment 1 of the present invention is viewed from an oblique direction, and FIG. 3 is a configuration diagram in which the charging unit provided in the electrostatic precipitator is viewed from above. 4 is a configuration diagram showing a cross section (A-A cross section of FIG. 3) of the charging unit provided in the electrostatic precipitator.

  As shown in FIG. 2, the charging unit 2 includes a plurality of discharge electrodes 4, a discharge electrode fixing member 5, a discharge electrode support member 6, a ground electrode 7, a ground electrode support member 8, and a frame body 9. I have. The discharge electrode 4 includes a needle-like discharge member 10 and a discharge member support 11, and the tip of the discharge member 10 supported by the same discharge member support 11 so that the tips of the discharge member 10 are all directed in the same direction. It is being fixed to the discharge member support body 11 so that the space | interval P may be 15-20 mm (this embodiment 20 mm). The discharge electrode 4 is fixed to the discharge electrode fixing member 5, and the discharge electrode fixing member 5 is fixed to the frame body 9 through the insulator 12.

  In the present embodiment, a high voltage of minus 8 kV is applied to the discharge electrode 4 and 0 V (that is, ground) is applied to the ground electrode 7. Thereby, corona discharge (minus discharge in the present embodiment) occurs between the discharge electrode 4 and the ground electrode 7, and dust contained in the air that has passed is negatively charged.

  In the present embodiment, the discharge member 10 is disposed so that the tip thereof faces the leeward direction. This is because the flow direction of the ion wind generated by corona discharge matches the flow direction of the air flowing into the charging unit 2, thereby reducing the turbulence of the wind flow due to the collision and charging the dust contained in the air. This is to increase the efficiency.

  In the present embodiment, the discharge member 10 has a needle-like shape with a sharp tip. The diameter of the tip is preferably about 10 to 300 μm in order to concentrate the electric field and cause corona discharge. In the present embodiment, the diameter is set to 30 μm. As other shapes, a rod shape having a diameter of about 10 to 300 μm or a spine shape may be used. The spine-shaped object can be produced, for example, by punching a sheet metal having a thickness of about 0.3 to 2 mm.

  The material of the discharge member 10 is preferably a material that is small in wear due to corona discharge, and is stainless steel in the present embodiment. As other materials, tungsten, titanium, Ni—Cr alloy, or the like may be used. As long as discharge is possible, a material containing carbon, tin, SiC, or the like may be used.

  The discharge electrode 4 comprises a discharge member 10 and a discharge member support 11, and the discharge member 10 is fixed to the discharge member support 11 using a fixing method such as welding or caulking. In the present embodiment, the material of the discharge member support 11 is stainless steel. This is because the same material as that of the discharge member 10 is used to prevent corrosion (electric corrosion) due to a potential difference caused by dissimilar metal bonding. In addition, it is not limited to stainless steel, and it is only necessary that the influence of electrolytic corrosion is small. Tungsten, titanium, Ni—Cr alloy, anodized aluminum, or the like may be used.

  In the present embodiment, the material of the discharge electrode fixing member 5 is stainless steel. This is to prevent electrolytic corrosion due to dissimilar metal bonding by using the same material as the discharge electrode 4. In addition, it is not limited to stainless steel, and it is only necessary that the influence of electrolytic corrosion is small. Tungsten, titanium, Ni—Cr alloy, anodized aluminum, or the like may be used.

  In the present embodiment, the material of the discharge electrode support member 6 and the insulator 12 is polypropylene. This is to ensure high insulation and durability against substances that promote oxidation such as ozone generated by corona discharge. Also, since polypropylene is inexpensive and can be easily molded, it can be easily manufactured and cost can be reduced. As another material, polyacetal or the like may be used. When higher durability is required, ceramics or the like may be used.

  As shown in FIG. 3, in the present embodiment, the discharge member 10 and the ground electrode 7 are arranged so that a certain distance G is 20 mm or less, and G = 20 mm.

  According to the above configuration, by setting the interval P between the tips of the discharge members 10 to 15 to 20 mm (20 mm in the present embodiment), the corona discharge from each discharge member 10 is uniform without interfering. Therefore, it is possible to charge the dust efficiently, so that an electric dust collector having high dust collection performance can be obtained.

  If the interval P is smaller than 15 mm, the electric field formed in each discharge member 10 interferes and corona discharge is less likely to occur, which may reduce the dust collection performance. If P is larger than 20 mm, a gap is generated in the area of corona discharge from each discharge member 10 to the ground electrode 7, and the dust passing through the gap is not charged, which may reduce the dust collection performance.

  As shown in FIG. 4, in the present embodiment, the discharge member 10 is arranged on the surface of the ground electrode 7 so that the overlap X between the discharge member 10 and the ground electrode 7 is 5 mm or more. And X = 7 mm.

  3 and 4, the gap G between the discharge member 10 and the ground electrode 7, and the overlap X between the discharge member 10 and the ground electrode 7 when the discharge member 10 is projected onto the surface of the ground electrode 7. This relationship always satisfies 20 mm ≧ G> X ≧ 5 mm.

  The gap G between the discharge member 10 and the ground electrode 7 when the gap G between the discharge member 10 and the ground electrode 7 is 20 mm or less (20 mm in the present embodiment) and the discharge member 10 is projected onto the surface of the ground electrode 7. By setting X to 5 mm or more (7 mm in the present embodiment), and making the gap G between the discharge member 10 and the ground electrode 7 larger than the overlap X between the discharge member 10 and the ground electrode 7 (G> X), An area where corona discharge from the discharge member 10 spreads with respect to the ground electrode 7 to a certain extent before the landing area when viewed from the air flow direction to some extent, and dust does not easily adhere to the ground electrode 7 By generating B (the white portion on the ground electrode 7 shown in FIG. 4), it becomes possible to maintain corona discharge over a long period of time, so that the electric dust collector can maintain high dust collection performance over a long period of time. Get Door can be.

  When the overlap X between the discharge member 10 and the ground electrode 7 when the discharge member 10 is projected onto the surface of the ground electrode 7 is smaller than 5 mm, a region B where dust is difficult to adhere to can be created on the ground electrode 7. However, as it is used, dirt is attached to the entire ground electrode 7 and the surface state of the ground electrode 7 changes, so that the corona discharge is gradually weakened and the dust collection performance may be lowered.

  If the gap G between the discharge member 10 and the ground electrode 7 is larger than 20 mm, the corona discharge from the discharge member 10 to the ground electrode 7 becomes too wide to sufficiently charge the passing dust, and the dust collection performance is improved. There is a risk of lowering.

  FIG. 5 is a configuration diagram of the ground electrode 7 provided in the electrostatic precipitator according to Embodiment 1 of the present invention.

As shown in FIG. 5, the ground electrode 7 has a configuration in which a resistor 14 is provided on the surface of the insulating substrate 13, and the surface resistivity of the resistor 14 is 10 ⁶ Ω / □ or more to 10 ^10. The range is less than Ω / □. The resistor 14 does not necessarily need to cover the entire surface of the insulating base material 13, but ranges from the portion overlapping the discharge member 10 to the ground electrode support member 8 that supports the ground electrode 7 and is connected to the ground. It is necessary to provide so that it covers.

  The surface resistivity was measured by the following method.

A cylindrical main electrode (diameter d, unit is cm) and a ring-shaped counter electrode (ring inner diameter D, unit is cm) so as to surround the main electrode are placed on the test piece so that the distance is constant. Put. Conductive rubber is sandwiched between the main electrode and the test piece to reduce contact resistance. Next, 0 V (connected to the ground) is applied to the main electrode, 1000 V is applied to the counter electrode, the current flowing between them is measured, and the surface resistance R is calculated. In this method, the surface resistivity ρs is obtained from the calculated R, the distance L in the direction of current flow on the test piece, and the length W of the electrode in the direction perpendicular to the direction of current flow.
ρs = R × W / L
W = π (D + d)
L = D−d
The unit of surface resistivity is [Ω / □] or simply [Ω], but in this patent, [Ω / □] is used, which is easy to distinguish from a simple resistance value.

The material of the insulating substrate 13 may be an inorganic material that is not easily corroded by an oxidizing substance such as ozone, or a fluororesin, and may be a ceramic or a fluororesin. As the ceramic, an oxide or composite oxide, carbide, nitride, or the like containing Si, Al, Zn, Ti, Mg, or the like can be used. From the viewpoint of cost and availability, in this embodiment, alumina and did. The insulating substrate 13 is preferably insulating, and the surface resistivity of the insulating substrate 13 is preferably 10 ¹⁰ Ω / □ or more.

  The material of the resistor 14 is formed by appropriately dispersing and fixing a conductive material in a binder. The binder is not particularly limited as long as the conductive material can be appropriately dispersed and fixed with respect to the insulating substrate 13, and glass powder, colloidal silica, a silicate compound, a titanate compound, or the like may be used. Glass powder is preferably chemically inert and oxidation resistant. Alumina, zirconia, titania powder or fluororesin particles may be used. The size of the adhesive is preferably larger than the conductive material particles in order to stabilize the shape, and is preferably about 2 to 100 times the size of the conductive material.

As the conductive material, tin oxide (SnO ₂ ) is preferable because of its stability against oxidation and availability, and ZnO, PbO ₂ , CdO, In ₂ O ₃ , Tl ₂ O ₃ , and Ga ₂ O _{3 are also available.} Further, oxide conductive materials such as Fe ₃ O ₄ and composite oxides thereof can be used. As the conductive agent, tin oxide doped with antimony (Sb) or the like may be used.

  In the present embodiment, as the resistor 14, glass powder as a binder, antimony-doped tin oxide as a conductive material, and a paste prepared by adding a solvent to the above components are mixed on the insulating substrate 13. A film formed by coating and baking was used.

In the region where the surface resistivity is less than 10 ⁶ Ω / □, spark discharge occurs and charges dust when the distance between the discharge electrode 4 and the ground electrode 7 becomes extremely small due to unintended deposits or the like. The capacity may decrease, and as a result, the dust collection performance may decrease. In the region where the surface resistivity is 10 ¹⁰ Ω / □ or more, corona discharge is less likely to occur between the discharge electrode 4 and the ground electrode 7, and the ability to charge dust is reduced, resulting in a decrease in dust collection performance. there's a possibility that.

According to the configuration as described above, the resistor 14 is provided on the surface of the insulating base 13, and the surface resistivity of the resistor 14 is 10 ⁶ Ω / □ or more and less than 10 ¹⁰ Ω / □, It is possible to generate corona discharge while suppressing the occurrence of spark discharge, and it is possible to obtain an electric dust collector that does not deteriorate dust collection performance due to spark discharge.

  In this embodiment, a high voltage of minus 8 kV is applied to the discharge electrode 4 and 0 V (that is, ground) is applied to the ground electrode 7. However, the present invention is not limited to this, and the discharge electrode 4 and the ground electrode 7 are not limited thereto. Any voltage can be used as long as it can cause corona discharge between the two.

In the present embodiment, the ground electrode 7 has a configuration in which the resistor 14 is provided on the surface of the insulating base material 13. However, the present invention is not limited to this, and the resistor provided on the surface of the ground electrode 7. The surface resistivity of 14 may be 10 ⁶ Ω / □ or more and less than 10 ¹⁰ Ω / □. For example, all the ground electrodes 7 may be made of the same material, and the surface resistivity may be 10 ⁶ Ω / □ or more and less than 10 ¹⁰ Ω / □.

  The electrostatic precipitator according to the present invention can maintain corona discharge over a long period of time by creating a region on the ground electrode where the dust is difficult to adhere, so that high dust collection performance can be maintained over a long period of time. Therefore, it is useful as an indoor circulation type air purification device, an air purification device that cleans the outside air and takes it into the room, and the like.

DESCRIPTION OF SYMBOLS 1 Electric dust collector 2 Charging part 3 Dust collection part 4 Discharge electrode 5 Discharge electrode fixing member 6 Discharge electrode support member 7 Ground electrode 8 Ground electrode support member 9 Frame body 10 Discharge member 11 Discharge member support body 12 Insulator 13 Insulation base Material 14 Resistor 101 Electric dust collector 102 Support body 103 Discharge member 104 Discharge electrode 105 Ground electrode

Claims (2)

In an electrostatic precipitator having a charging part for charging dust in the air and a dust collecting part for collecting charged dust,
The charging unit includes a plurality of discharge electrodes, a discharge electrode fixing member, a discharge electrode support member, a ground electrode, a ground electrode support member, and a frame.
The discharge electrode is composed of a needle-shaped discharge member and a discharge member support, so that the tips of the discharge members are all directed in the same direction, and the interval between the tips of the discharge members is 15 to 20 mm. Fixed to the discharge member support,
The interval between the discharge member and the ground electrode is 20 mm or less,
When the discharge member is projected on the surface of the ground electrode, the overlap between the discharge member and the ground electrode is 5 mm or more,
The electrostatic precipitator according to claim 1, wherein an interval between the discharge member and the ground electrode is larger than an overlap between the discharge member and the ground electrode. The current collector according to claim 1, wherein the ground electrode is provided with a resistor on a surface thereof, and the surface resistivity of the resistor is 10 ⁶ Ω / □ or more and less than 10 ¹⁰ Ω / □. Dust equipment.

Images