JP6562836B2 - Electric dust collector - Google Patents

Description

  The present invention relates to an electric dust collector that collects dust charged by a charging unit using a collecting unit.

  An electric dust collector that collects dust charged by a charging unit by a collecting unit has become widespread (see Patent Document 1). The collector is configured by arranging a plurality of high voltage plates and a plurality of ground plates so that a high voltage plate that applies a positive high voltage and a ground plate are opposed to each other by a predetermined distance. Have

JP-A-7-108191

  In order to lighten the electrostatic precipitator, the ground electrode plate is not a metal plate but a resin plate with conductive coating on both sides may be used. A ground electrode plate having a predetermined shape is formed by punching a resin plate having conductive coating on both sides thereof by press working.

  An electric dust collector is required to improve dust collection efficiency as much as possible. It has been clarified that the use of an earth electrode plate formed by stamping a resin plate by press working lowers the dust collection efficiency than when a metal plate earth electrode plate is used.

  An object of the present invention is to provide an electrostatic precipitator that uses a resin plate provided with a conductive coating as a ground electrode plate, and can improve dust collection efficiency as compared with the prior art.

  In order to solve the above-described problems of the prior art, the present invention is configured so that a charging unit that positively charges dust contained in air, a high-voltage electrode plate, and a ground electrode plate are spaced apart from each other by a predetermined distance. And a collecting part for collecting dust positively charged by the charging part by the earth electrode plate, wherein the charging part and the collecting part are arranged to face each other, and the earth electrode plate Is provided with a resin plate with conductive coating on both sides, and a painted portion with conductive coating, and an uncoated portion that is an end portion on the charged portion side of the resin plate and is not subjected to conductive coating. The electrostatic precipitator is characterized in that an end on the charging part side of the high-voltage electrode plate does not face the unpainted part but faces the painted part.

  In the electric dust collector, a width of the ground electrode plate along a direction in which charged dust flows from the charging unit to the collecting unit is wider than a width of the high voltage electrode plate along the direction, and the high voltage The end of the electrode plate opposite to the charged portion side is opposite to the end of the ground electrode plate opposite to the charged portion side, and the unpainted portion is the end of the high-voltage electrode plate. It is preferable to protrude from the end on the charged part side toward the charged part side.

  According to the electric dust collector of the present invention, it is possible to improve the dust collection efficiency as compared with the prior art by using a resin plate provided with conductive coating as the ground electrode plate.

It is a conceptual diagram which shows the charge part with which the electrostatic precipitator by one Embodiment is equipped, a collection part, and a high voltage power supply. It is an external appearance perspective view which shows the whole structure of the electrostatic precipitator by one Embodiment. It is a conceptual diagram of the charge part and the collection part with which the electrostatic precipitator by one Embodiment is provided. It is a conceptual sectional view for explaining a problem of a conventional electrostatic precipitator using a resin plate subjected to conductive coating as a ground electrode plate. It is a conceptual sectional view for explaining an operation effect by an earth electrode plate with which an electric dust collector by one embodiment is provided. It is a top view which shows the earth electrode plate with which the electrostatic precipitator by one Embodiment is provided. It is a conceptual sectional view for explaining that a plus ion flows from a charge part to a collection part. It is a conceptual sectional view for explaining a problem that occurs when an earth electrode plate has an unpainted portion at an end portion on a charged portion side. FIG. 9 is a conceptual cross-sectional view illustrating a configuration of a collection unit included in an electric dust collector according to an embodiment that solves the problem described in FIG. 8. It is a conceptual sectional view for explaining an operation effect by a collection part with which an electric dust collector by one embodiment is provided. FIG. 10 is a conceptual cross-sectional view showing a first modification. 10 is a plan view partially showing a wire mesh used in Modification 1. FIG. FIG. 10 is a conceptual cross-sectional view showing a second modification.

  Hereinafter, an electric dust collector according to an embodiment will be described with reference to the accompanying drawings. First, the overall configuration of the electrostatic precipitator 100 according to an embodiment will be described with reference to FIGS. 2 and 3.

  2, the electrostatic precipitator 100 includes a charging unit storage housing 101 that stores the charging units 10A and 10B shown in FIG. 3, and a collection unit storage housing 102 that stores the collection units 20A and 20B shown in FIG. Is provided. The charging unit storage housing 101 may store only one of the charging unit 10A and the charging unit 10B, and the collection unit storage housing 102 stores only one of the collection unit 20A and the collection unit 20B. May be.

  The charging units 10A and 10B are collectively referred to as the charging unit 10. The collection units 20A and 20B are collectively referred to as the collection unit 20. The number of sets of the charging unit 10 and the collection unit 20 stored in the charging unit storage case 101 and the collection unit storage case 102 is arbitrary.

  The charging unit 10 and the collecting unit 20 are close to each other and face each other. The charging unit 10 charges dust contained in the air flowing in the X direction from the front side of FIG. The collecting unit 20 collects charged dust and discharges air from which dust is removed from the rear of the collecting unit housing 102.

  FIG. 3 conceptually illustrates a state where the charging unit 10 and the collection unit 20 are cut along the XY plane of FIG. In FIG. 3, the charging unit 10 includes, for example, five plate-like counter electrodes 11 and four ionization lines 12 disposed at a substantially central portion between the pair of counter electrodes 11. The ionization line 12 has a diameter of about 0.12 mm, for example, and has a predetermined length in a direction perpendicular to the paper surface.

  In FIG. 3, air flows into the inside through the opening between the counter electrodes 11 from above in FIG. 3.

  The collection unit 20 is arranged such that a plurality of plate-shaped high-voltage electrode plates 21 and a plurality of plate-shaped ground electrode plates 22 face each other with a predetermined distance therebetween. The distance between the high-voltage electrode plate 21 and the earth electrode plate 22 is much narrower than the distance between the pair of counter electrodes 11, and the high-voltage electrode plate 21 and the earth electrode plate 22 have a much larger number than the counter electrode 11.

  The number of counter electrodes 11, the number of ionization wires 12, and the number of high-voltage electrode plates 21 and ground electrode plates 22 are not particularly limited.

  With reference to FIG. 1, how the charging unit 10 and the collection unit 20 are connected to the power source and how the charging unit 10 and the collection unit 20 operate will be described.

  As shown in FIG. 1, the counter electrode 11 is connected to the ground, and the ionization line 12 is connected to the plus side of the high-voltage power supply 13. For example, a high voltage of +5 kV is applied to the ionization line 12.

  As a result, corona discharge occurs between the counter electrode 11 and the ionization line 12 as indicated by an arrow indicated by a one-dot chain line. In FIG. 1, corona discharge is shown only between one pair of counter electrodes 11, but corona discharge similarly occurs between other pairs of counter electrodes 11. When the air passes between the counter electrodes 11, dust contained in the air is positively charged and flows in the direction of the collecting unit 20.

  The high voltage electrode plate 21 is connected to the positive side of the high voltage power source 23. For example, a high voltage of +4.5 kV is applied to the high-voltage electrode plate 21. The ground electrode plate 22 is connected to the ground. Therefore, an electric field is generated from the high-voltage electrode plate 21 toward the earth electrode plate 22.

  The positively charged dust passing between the high-voltage electrode plate 21 and the earth electrode plate 22 is collected by the earth electrode plate 22. The ground electrode plate 22 is an electrode that collects dust and may be referred to as a dust collection electrode. The high voltage electrode plate 21 may be referred to as a non-dust collecting electrode.

  As described above, the electrostatic precipitator 100 including the charging unit 10 and the collection unit 20 can collect dust contained in the air.

The high-voltage electrode plate 21 is formed in a predetermined shape using, for example, a semiconductive resin. The shape of the high-voltage electrode plate 21 is the same as that of a ground electrode plate 22 described later. The resistivity (volume resistivity) of the semiconductive resin is 10 ¹⁰ Ωcm to ^{10 13} Ωcm.

  The ground electrode plate 22 is formed in a predetermined shape by punching a resin plate having conductive coating on both sides thereof by a press process such as a Thomson process. By using a ground plate 22 as a resin plate instead of a metal plate, the electrostatic precipitator 100 can be lightened.

  Here, with reference to FIG. 4, problems of a conventional electrostatic precipitator using a resin plate subjected to conductive coating as the ground electrode plate 22 will be described. As shown in FIG. 4, the earth electrode plate 22 includes a resin plate 221 made of, for example, polyvinyl chloride (PCV) that functions as an insulating layer, and a conductive coating 222 applied to both surfaces of the resin plate 221.

  It is assumed that the direction indicated by the arrow in FIG. 4 is the drawing direction in Thomson processing. In this case, the ground electrode plate 22 is formed with burrs 223 at the end of one surface that is downstream in the pulling direction, and the sagging 224 is formed at the end of the other surface that is upstream in the pulling direction. .

  The following has been clarified by the verification by the present inventors. When a positive high voltage is applied to the high-voltage plate 21, the polarity of the high-voltage plate 21 is opposite to the portion of the burrs 223 due to the inequality between the surface of the high-voltage plate 21 and the tip of the burrs 223. It occurs when the electric field strength exceeds a certain level of negative discharge. The negative discharge generated in the portion of the burrs 223 neutralizes the positively charged dust. As a result, the dust collection efficiency decreases.

  Therefore, in the present embodiment, the ground electrode plate 22 is configured as shown in FIGS. In FIG. 5, the ground electrode plate 22 is formed in a predetermined shape by press working such as Thomson processing, with the direction indicated by the arrow as the drawing direction. As in FIG. 4, a burley 223 and a sag 224 are formed at the end of the resin plate 221.

  As shown in FIG. 5, the conductive coating 222 is applied to both surfaces of the resin plate 221 so as to avoid the ends including the burrs 223 and sagging 224. Both surfaces of the end including the burrs 223 and sagging 224 are unpainted portions 225.

  Although the unpainted portion 225 may be provided only on the surface where the burrs 223 are formed, the unpainted portion 225 may be provided on both surfaces of the resin plate 221.

  When the thickness of the resin plate 221 is 0.7 mm, the unpainted portion 225 may be in a range of about 1 mm from the outer peripheral end of the resin plate 221. The unpainted portion 225 is preferably in the range of the plate thickness or more.

  As an example, the ground electrode plate 22 is formed in a planar shape as shown in FIG. The ground electrode plate 22 is formed with a recess 226 for mounting a support member for supporting a plurality of ground electrode plates 22 and a ground member for connecting to the ground. The shape of the ground electrode plate 22 shown in FIG. 6 is merely an example, and the shape is not limited.

  A method of providing the unpainted portion 225 on the resin plate 221 is not particularly limited, but may be performed as follows, for example. In FIG. 6, a conductive coating 222 is applied to the resin plate 221 so as to form an unpainted portion 225 of about 1 mm at the outer peripheral end portion by silk screen printing.

  In the electrostatic precipitator 100 including the collector 20 having the ground electrode plate 22 having the unpainted portion 225 formed on the outer peripheral end as shown in FIGS. 5 and 6, the above-described inequality is suppressed, Negative discharge does not occur in the part. Therefore, neutralizing positively charged dust can be suppressed.

  By the way, as shown in FIG. 7, positive ions generated in the charging unit 10 flow to the collection unit 20. Then, since the ground electrode plate 22 has the unpainted portion 225, as shown in FIG. 8, the positive ions positively charge the unpainted portion 225 at the end of the resin plate 221 on the charging portion 10 side.

  As a result, the local electric field from the unpainted portion 225 toward the conductive coating 222 affects the electric field formed between the high-voltage electrode plate 21 and the ground electrode plate 22. The dust charged positively in the charging unit 10 is repelled from the unpainted part 225 charged positively. Therefore, in the state shown in FIG. 8, dust is not easily collected by the ground electrode plate 22.

  Therefore, in the present embodiment, the ground electrode plate 22 is configured as shown in FIGS. 9 and 10 in addition to the configurations shown in FIGS. 5 and 6.

  The charging unit 10 side (upper side in FIG. 9) is the upstream side in the direction in which the positively charged dust flows, and the collecting unit 20 side (lower side in FIG. 9) is the downstream side in the direction in which the dust flows. As shown in FIG. 9, the width W22 of the ground electrode plate 22 along the direction in which dust flows is wider than the width W21 of the high-voltage plate 21 along that direction.

  The downstream end of the high-voltage electrode plate 21 and the downstream end of the ground electrode plate 22 are at the same position in the direction in which dust flows and are opposed to each other. The upstream end of the ground plate 22 protrudes upstream from the upstream end of the high-voltage plate 21, and the upstream end of the ground plate 22 is the upstream end of the high-voltage plate 21. It does not face the part.

  As in FIG. 8, as shown in FIG. 10, positive ions generated in the charging unit 10 and heading toward the collection unit 20 positively charge the unpainted part 225 of the resin plate 221. Since the upstream end of the ground electrode plate 22 projects upstream, the end of the high-voltage electrode plate 21 does not face the unpainted portion 225 but faces the painted portion 227.

  Therefore, the local electric field from the unpainted portion 225 that is positively charged toward the conductive coating 222 has little influence on the electric field formed between the high-voltage electrode plate 21 and the ground electrode plate 22. The dust charged positively at the charging unit 10 hardly receives repulsion from the unpainted part 225 charged positively.

  Therefore, when the collection part 20 is provided with the earth electrode plate 22 comprised as shown in FIG. 10, the dust collected by the earth electrode plate 22 can be increased compared with FIG. That is, according to the present embodiment, the dust collection efficiency can be improved as compared with the conventional case.

  In both the configuration shown in FIG. 8 and the configuration shown in FIG. 10, the applied voltage of the high voltage plate 21 is 6.25 kV, the distance between the high voltage plate 21 and the ground plate 22 is 2.85 mm, The electric field strength between the ground electrode plate 22 was 2.19 kV / mm. The difference between the width W21 and the width W22 was 6 mm, and the ground electrode plate 22 was protruded 6 mm from the high voltage electrode plate 21 toward the charging unit 10 side.

  Under these conditions, the dust collection efficiency of the configuration shown in FIGS. 8 and 10 was measured. The volume flow rate Q was 56.7 CMM (Cubic Meter per Minute), and dust collection efficiency for collecting 0.5 to 1.0 μm dust was measured.

  As a result of the measurement, the dust collection efficiency in the configuration shown in FIG. 8 was 43.2%, whereas the dust collection efficiency in the configuration shown in FIG. 10 was 61.6%, which can improve the dust collection efficiency. It was confirmed.

  FIG. 11 shows a first modification. In the modification shown in FIG. 11, the upstream end of the ground electrode plate 22 is not projected, and the configuration of the collection unit 20 is the same as that in FIG. 7. As shown in FIG. 11, a wire mesh 31 as shown in FIG. 12 is arranged between the charging unit 10 and the collection unit 20.

  For example, the wire mesh 31 has a metal wire diameter of 0.8 mm and a pitch of 10 mm. The wire mesh 31 is connected to the ground having the same potential as that of the ground electrode plate 22.

  The positive ions generated in the charging unit 10 and traveling toward the collection unit 20 are captured by the wire mesh 31 and flow to the ground before being charged to the unpainted portion 225 of the resin plate 221. Therefore, charging to the unpainted part 225 is suppressed.

  The applied voltage of the high-voltage plate 21, the distance between the high-voltage plate 21 and the earth plate 22, and the electric field strength between the high-voltage plate 21 and the earth plate 22 are the same as described above, and the modification 1 shown in FIG. The dust collection efficiency was measured. The dust collection efficiency in Modification 1 was 63.3%, and it was confirmed that the dust collection efficiency was improved.

  When the configuration shown in FIGS. 9 and 10 is compared with the first modification shown in FIG. 11, the dust collection efficiency is slightly higher in the first modification. 9 and 10, the dust collection efficiency is slightly lower than that of the first modification, but it is preferable because it is not necessary to provide a separate part such as the wire mesh 31. Since it is only necessary to make the width W22 of the ground electrode plate 22 wider than the width W21 of the high-voltage electrode plate 21, the dust collection efficiency can be improved with a simple configuration at a low cost.

  FIG. 13 shows a second modification. In the second modification shown in FIG. 13, the upstream end of the ground electrode plate 22 is not projected, and the configuration of the collection unit 20 is the same as that in FIG. 7. As shown in FIG. 13, a metal round bar 32 having a predetermined length is disposed between the charging unit 10 and the collection unit 20 in a direction orthogonal to the paper surface. The metal round bar 32 has the same effect as the wire mesh 31.

  The applied voltage of the high-voltage electrode plate 21, the distance between the high-voltage electrode plate 21 and the earth electrode plate 22, and the electric field strength between the high-voltage electrode plate 21 and the earth electrode plate 22 are the same as described above, and the modification 2 shown in FIG. The dust collection efficiency was measured. The dust collection efficiency in Modification 2 was 62.6%, and it was confirmed that the dust collection efficiency was improved.

  When the configuration shown in FIGS. 9 and 10 is compared with the second modification shown in FIG. 13, the dust collection efficiency is slightly higher in the second modification. Similarly, the configuration shown in FIGS. 9 and 10 is preferable because it is not necessary to provide another component called the metal round bar 32. Since it is only necessary to make the width W22 of the ground electrode plate 22 wider than the width W21 of the high-voltage electrode plate 21, the dust collection efficiency can be improved with a simple configuration at a low cost.

  The present invention is not limited to the embodiment described above, and various modifications can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 10,10A, 10B Charge part 11 Counter electrode 12 Ionization line 20, 20A, 20B Collection part 21 High voltage electrode plate 22 Ground electrode plate 221 Resin plate 222 Conductive coating 223 Kayari 224 Sag 225 Unpainted part 227 Painted part

Claims (2)

A charging unit that positively charges dust contained in the air;
A high-voltage plate and a ground plate are arranged so as to face each other with a predetermined distance apart, and a collection unit that collects dust positively charged by the charging unit with the ground plate,
With
The charging unit and the collecting unit are arranged to face each other,
The ground electrode plate is provided with a resin plate having conductive coating on both sides, and is a coated portion on which conductive coating is applied and an end portion on the charging portion side of the resin plate, which is not applied with conductive coating. With unpainted parts,
The electrostatic precipitator according to claim 1, wherein an end of the high-voltage electrode plate on the charging part side does not face the unpainted part but faces the painted part. The width of the ground electrode plate along the direction in which the charged dust flows from the charging unit to the collecting unit is wider than the width of the high-voltage electrode plate along the direction,
The end of the high-voltage plate opposite to the charged portion is opposite to the end of the ground plate opposite to the charged portion.
2. The electrostatic precipitator according to claim 1, wherein the unpainted portion protrudes toward the charged portion side from an end portion on the charged portion side of the high-voltage electrode plate.

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