JP6260915B2 - Electric dust collector - Google Patents

Description

  The present invention relates to an electrostatic precipitator including a charging device that charges particles such as fine dust and mist in dust-containing air by corona discharge generated by application of a high voltage.

  Conventionally, an industrial electrostatic precipitator has been used to perform air purification in a factory by sucking dust-containing air generated from a processing machine such as a machining center. The electrostatic precipitator is provided with a charging device that charges particles such as fine dust and mist in the dust-containing air by corona discharge generated by application of a high voltage.

  As a conventional electrostatic precipitator equipped with this type of charging device, for example, as disclosed in Patent Document 1, a support substrate in which a large number of discharge needle electrodes are arranged side by side in a vertically spaced manner is used. , One provided with a charging device constructed by being attached so as to maintain a certain distance from the ground electrode plate between a plurality of ground electrode plates arranged side by side, or as disclosed in Patent Document 2, There are known ones including a charging unit configured by alternately disposing a protruding discharge electrode for applying a voltage and a ground electrode plate connected to the ground.

JP 2007-222717 A JP 2008-207168 A

  However, in the electric dust collector disclosed in Patent Document 1 or 2 described above, as the fine dust and mist in the dust-containing air are sucked, the fine dust and mist are gradually deposited on the ground electrode plate, and the amount of the accumulated dust is constant. If the distance between the ground electrode and the discharge needle electrode is reduced when the amount reaches, the abnormal discharge may occur and the operation may be stopped, or the temperature may rise to cause the worst fire, Alternatively, there is a problem that deposits on the ground plate re-scatter.

  In addition, since a plurality of ground electrode plates are provided, it takes time to clean and remove fine dust and mist adhering to and deposited on the ground electrode plate, and it is difficult to improve usability.

  Furthermore, since the ground electrode plates are provided in parallel along the flow direction of the dust-containing air, it is difficult to shorten the length of the charging device in the longitudinal direction (the flow direction of the dust-containing air). In addition, since the dust collector is a mechanism that adsorbs (collects) fine dust and mist charged by the charging device, a predetermined length is required in the longitudinal direction, and the length of the dust collector in the longitudinal direction. Is difficult to shorten. Therefore, the electric dust collector described in Patent Document 1 or 2 has a problem that it is difficult to reduce the size of the product. The same applies to a dust collector using a rotating electrode plate.

  Furthermore, in the electric dust collector of Patent Document 1 described above, in order to widen the charging region, a configuration in which the discharge needle electrodes are obliquely arranged with respect to the flow direction of the dust-containing air has also been proposed. Even when the configuration is adopted, due to the structure in which the discharge needle electrode and the grounding electrode plate are arranged in parallel to the dust-containing air, there is inevitably an area where the discharge is weak, and all fine dust in the dust-containing air In addition, since the mist cannot be charged, it is difficult to increase the charging efficiency, resulting in a decrease in the collection efficiency.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide an electrostatic precipitator with excellent charging efficiency that can reliably charge fine dust and mist in dust-containing air. It is.

  In order to solve the above-described problems, a first electrostatic precipitator according to the present invention includes an electrostatic precipitator including a charging device that charges particles such as fine dust and mist in dust-containing air by corona discharge generated by application of a high voltage. A ground electrode plate that is arranged in a direction that blocks the flow of dust-containing air and has a large number of openings through which the dust-containing air passes, and a discharge electrode that is arranged corresponding to each opening of the ground electrode plate. A support substrate for supporting, wherein the opening has a round hole shape and is provided in the same number as the distal end portion of the discharge electrode, and the support substrate supports the proximal end portion of the discharge electrode, and the grounding The electrode plate is disposed apart from the discharge electrode, and the distal end portion of the discharge electrode is located on the center line of the opening as viewed from the flow direction of the dust-containing air, and the distal end portion of the discharge electrode and the Between the periphery of the opening, a conical shape due to corona discharge And forming a conductive area.

  In the second electrostatic precipitator of the present invention, the distance between the tip of the discharge electrode and the peripheral edge of the opening is substantially equal to the diameter of the opening.

  According to the first and second electric dust collectors of the present invention, the dust-containing air passing through the opening can be uniformly charged, and the charging efficiency can be further increased. Moreover, the balance of the charging area by corona discharge can be made uniform in each opening, and the occurrence of abnormal discharge can be prevented.

  According to the present invention, fine dust and mist in dust-containing air can be reliably charged, and charging efficiency can be improved. Various excellent effects can be obtained.

It is a perspective view which shows the whole structure of the electrostatic precipitator which concerns on embodiment of this invention. It is a perspective view which shows the charging device of the electrostatic precipitator which concerns on embodiment of this invention. It is a front view which shows the charging device of the electrostatic precipitator which concerns on embodiment of this invention. It is a top view which shows the charging device of the electrostatic precipitator which concerns on embodiment of this invention. It is a side view which shows the charging device of the electrostatic precipitator which concerns on embodiment of this invention. It is a perspective view which expands partially and shows the charging device of the electrostatic precipitator which concerns on embodiment of this invention. It is a top view which shows the effect | action of the charging device of the electrostatic precipitator which concerns on embodiment of this invention. It is a front view which shows the effect | action of the charging device of the electrostatic precipitator which concerns on embodiment of this invention. It is a perspective view which shows the effect | action of the charging device of the electrostatic precipitator which concerns on embodiment of this invention. It is a top view which shows the modification of the charging device of the electrostatic precipitator which concerns on embodiment of this invention. It is a front view which shows the modification of the charging device of the electrostatic precipitator which concerns on embodiment of this invention. It is a side view which shows the modification of the electrostatic precipitator which concerns on embodiment of this invention. It is a top view which shows the effect | action of the charging device of the conventional electrostatic precipitator. It is a front view which shows the effect | action of the charging device of the conventional electrostatic precipitator.

  Hereinafter, an electric dust collector according to an embodiment of the present invention will be described with reference to the drawings.

  First, with reference to FIG. 1, the overall configuration and operation of the electrostatic precipitator according to the embodiment of the present invention will be schematically described. Here, FIG. 1 is a perspective view showing the overall configuration of the electrostatic precipitator according to the embodiment of the present invention.

  The electrostatic precipitator according to the embodiment of the present invention includes a rectangular parallelepiped main body case 1. A suction port 2 is opened on the front side of the main body case 1, and an intake duct 3 is connected to the suction port 2. Yes. An exhaust port 4 is opened on the back side of the upper surface of the main body case 1, and an open / close door 5 is attached to the right side surface of the main body case 1 so as to be opened and closed. In addition, in FIG. 1, the intake duct 3 and the door 5 are shown with the dashed-two dotted line for convenience so that the state inside an electric dust collector can be visually recognized.

  Inside the main body case 1, a prefilter (not shown), a charging device 6, a dust collector 7, and a fan (not shown) are arranged along the flow direction of dust-containing air (denoted Air in the drawing). The motor 8 is attached to the back side of the main body case 1 as a drive source for rotating the fan.

  The details of the charging device 6 will be described later.

  As the dust collector 7, a plurality of rotating electrode plates (not shown) that are arranged in parallel at equal intervals in the outer frame 10 and that can rotate via the central shaft 11 are interposed between the rotating electrode plates. And a plurality of fixed electrode plates (not shown) are used. Note that the dust collector 7 is not limited to this rotating electrode type. For example, other types such as a dust collector that does not use a rotating electrode plate disclosed in JP-A-2007-222717 are used. It doesn't matter.

  In the electric dust collector having the above-described configuration, the dust-containing air generated from a processing machine such as a machining center passes through the intake duct 3 into the main body case 1 through the intake duct 3 by the suction of the fan that is rotated by driving the motor 8. Sucked. The dust-containing air that has flowed into the main body case 1 is filtered by the pre-filter and then subjected to corona discharge in the charging device 6 to charge particles such as fine dust or mist in the dust-containing air. Thereafter, particles such as charged fine dust or mist are collected in the dust collector 7, whereby the dust-containing air is filtered to become clean air, and is discharged from the exhaust port 4 to the outside of the electric dust collector.

  Next, the charging device 6 of the electrostatic precipitator according to the embodiment of the present invention will be described in detail with reference to FIGS. 2 is a perspective view showing the charging device 6, FIG. 3 is a front view showing the charging device 6, FIG. 4 is a plan view showing the charging device 6, FIG. 5 is a side view showing the charging device 6, and FIG. It is a perspective view which expands and shows the charging device 6 partially.

  The charging device 6 includes a charging device body 12 and a high voltage power supply unit 13 that applies a high voltage to the charging device body 12. The high voltage power supply unit 13 is configured to boost the alternating current source 14 with a high voltage transformer 15 and then convert the alternating current into direct current with the voltage multiplying unit 16 and further boost the alternating current to generate a high voltage of about 10 KV. And also functions as an output control unit for controlling the output of the high voltage applied to the charging device main body 12.

  The charging device main body 12 includes a substantially rectangular frame 20 when viewed from the flow direction of the dust-containing air, a ground electrode plate 40 that is attached to the inside of the frame 20 and connected to the ground, and contains dust from the ground electrode plate 40. A support substrate 60 disposed on the downstream side in the air flow direction and a discharge needle electrode 80 as a discharge electrode that is cantilevered by the support substrate 60 are provided.

  The frame 20 includes left and right support columns 21 and 22 erected so as to face each other, an upper connecting member 23 provided between upper ends of the support columns 21 and 22, and lower ends of the support columns 21 and 22. Leg members 24 and 25 attached in directions close to each other, and an elongated rectangular hole 26 is formed in the upper connecting member 23 in the left-right direction.

  An upper mounting member 27 is horizontally mounted on the upper end portions of the left and right support columns 21 and 22 below the upper connecting member 23 via an insulator 28, and leg members are provided on the lower end portions of the left and right support columns 21 and 22, respectively. A lower mounting member 29 is placed above 24 and 25 via an insulator 28. Thereby, the upper mounting member 27 and the lower mounting member 29 are supported in a state insulated from the frame body 20.

A plurality of cutout portions 30 are formed in the lower attachment member 29 in a vertical slit shape at predetermined intervals (see FIG. 6). A power supply member 31 is attached to the left end portion of the lower mounting member 29, and the high voltage power supply unit 13 is connected to the power supply member 31. High voltage of about 10KV supplied from high voltage power source 13, power supply members 31, the lower mounting member 29, the supporting substrate 60, is applied to the discharge needle electrode 80, the tip of the discharge needle electrode 80 and the opening 41, a conical charging area EA is formed by corona discharge.

  The ground electrode plate 40 is formed in a flat plate shape from a single rectangular conductive metal (iron in the embodiment) in which a large number of round hole-shaped openings 41 are formed, such as a removable rivet. The attachment / detachment means is detachably attached to the frame body 20 in a direction that blocks the flow of the dust-containing air (direction orthogonal to the flow direction of the dust-containing air). As is well shown in FIG. 3, a plurality of openings 41 are connected in the vertical direction and are formed over a plurality of rows, and are vertically divided by half of the openings 41 between adjacent rows on the left and right. They are arranged in a staggered pattern at regular intervals so as to be staggered.

  In the present embodiment, 14 openings 41 are arranged in the vertical direction and are formed in 28 rows, and a total of 392 openings are provided, and the diameter of the openings 41 is set to 15 mm. The reason why the number and the opening area (diameter) of the openings 41 are set in this way is that the air volume of the dust-containing air to be processed by the electric dust collector is determined, and the discharge needle electrode 80 and the peripheral portion of the opening 41 are If the opening area of the opening 41 is made too small under the condition that the interval is constant, the passing air speed of the dust-containing air increases, and the charged area by the ion shower (air ions) discharged from the discharge needle electrode 80. The charging contact time between the EA and the particles in the dust-containing air is shortened. On the other hand, if the opening area of the opening 41 is excessively increased, the passage speed of the dust-containing air is reduced, but the charging area from the discharge needle electrode 80 is reduced. EA becomes narrow and cannot be sufficiently charged. Furthermore, the number of openings 41 provided in the ground electrode plate 40 is reduced, and the space efficiency is also deteriorated.

  The shape of the opening 41 is most preferably a perfect round hole as described above, but may be, for example, a regular polygonal substantially circular shape. The ground electrode plate 40 may be a commercially available punching metal plate. In this case, the cost can be further reduced.

  Referring to FIG. 2 again, the support substrate 60 is formed of a vertically long strip-shaped plate material, and in this embodiment, 14 support substrates 60 are provided in every other row between the left and right adjacent openings 41. The electrodes are arranged in a direction orthogonal to the electrode plate 40. As a result, the support substrates 60 are arranged so as not to interfere with the openings 41 when viewed from the flow direction of the dust-containing air, and the spacing between the support substrates 60 is maintained to the extent that no abnormal discharge occurs. Note that the support substrate 60 in this embodiment is arranged in a direction parallel to the flow direction of the dust-containing air and orthogonal to the ground electrode plate 40, but for example, so as not to interfere with the opening 41. As long as it is arranged, it may be arranged in a direction not orthogonal to the ground electrode plate 40.

  The upper end portion of the support substrate 60 is supported by the upper mounting member 27 by a spring (not shown) interposed between the hook hole 62 formed in the upper end portion and the upper mounting member 27. Further, the lower end portion of the support substrate 60 is formed in a hook shape and is supported by the lower mounting member 29 by being hooked by the notch portion 30.

  As well shown in FIG. 6, the number of the openings 41 corresponding to two rows of caulking portions 61 adjacent to the left and right of the support substrate 60 (14 × 2 in this embodiment) is provided on one support substrate 60. The number of stages corresponding to 28 rows) is formed, and two crimping portions 61 are formed in each stage.

  The discharge needle electrode 80 is made of a titanium alloy called 64 titanium, specifically, a JIS 60 type alloy (6% Al + 4% V + 90% Ti), for example, a thin wire having a diameter of φ0.5 mm to 0.6 mm. It is formed in a shape or a needle shape, and the tip is polished. The discharge needle electrodes 80 are cantilevered at the base end portions of the caulking portions 61 of each stage, and in this embodiment, 28 are attached to one support substrate 60, and the same number as the openings 41. Is provided.

  The discharge needle electrode 80 protrudes from the crimping portion 61 in the direction of the ground electrode plate 40 (that is, upstream of the support substrate 60 in the flow direction of the dust-containing air), and the tip of the discharge needle electrode 80 is connected to the ground electrode plate 40. The support substrate 60 is alternately bent so as to be positioned on the center line CL of the opening 41 adjacent to the left and right sides of the support substrate 60. Thereby, the front-end | tip part of the needle electrode for discharge and the peripheral part of the opening part 41 maintain a fixed space | interval.

  By configuring the discharge needle electrode 80 in this manner, the amount of ozone generated can be significantly reduced, the workability is excellent, and stable discharge is possible, and the wear amount of the discharge needle electrode 80 is suppressed, Long life can be achieved. Moreover, since the discharge needle electrode 80 made of 64 titanium is excellent in toughness, it is difficult to break when caulking or bending is possible, and durability can be improved.

  According to the electric dust collector having such a configuration, the ground electrode plate 40 is arranged in a direction orthogonal to the flow direction of the dust-containing air, and a large number of openings 41 are formed in the ground electrode plate 40. The ground electrode plate 40 functions not only as a ground plate of the charging device 6 but also as a function of rectifying the dust-containing air. Therefore, it is not necessary to provide a separate rectifying plate, and the cost can be reduced correspondingly. .

  In addition, since the ground electrode plate 40 is detachably provided to the frame body 20 and is composed of only one sheet metal, when the ground electrode plate 40 is contaminated by the deposition of fine dust or mist, In particular, dirt accumulated on the back surface side of the ground electrode plate 40 (downstream side in the direction in which the dust-containing air flows) can be easily cleaned, improving maintainability and reducing the number of components, resulting in cost reduction. Can be reduced. Further, by forming the ground electrode plate 40 with a single sheet metal disposed in an orthogonal direction that blocks the flow of dust-containing air, the size of the charging device 6 in the longitudinal direction (the flow direction of the dust-containing air) is shortened. The size of the electrostatic precipitator itself in the longitudinal direction can be reduced, and the overall height of the electrostatic precipitator can be reduced by arranging the charging device 6, the dust collector 7 and the fan 8 in series. Therefore, the product can be downsized.

  In addition, the ground electrode plate 40 is disposed upstream of the discharge needle electrode 80 in the direction of the flow of the dust-containing air, and is configured to charge fine dust and mist in the dust-containing air after passing through the ground electrode plate 40. Thus, it is possible to provide the charging device 6 in which fine dust and mist are less likely to adhere to the ground electrode plate 40 and are less likely to become dirty.

  Further, since the tips of the discharge needle electrodes 80 are arranged at predetermined intervals so as to correspond to all the openings 41 of the ground electrode plate 40, all the dust-containing air passing through the openings 41 is charged. Therefore, the charging efficiency can be improved.

Further, the distal end portion of the discharge needle electrode 80 is arranged so as to be located in an area within the peripheral edge portion of the opening 41 of the ground electrode plate 40 as viewed from the direction in which the dust-containing air flows. Furthermore, since the opening 41 of the ground electrode plate 40 has a round hole shape and the tip of the discharge needle electrode 80 is arranged on the center line of the opening 41, as shown in FIGS. , the distance to the periphery of the opening 41 from the tip of the discharge needle electrode 80 becomes uniform, the charging area EA by corona discharge which is formed by the discharge needle electrode 80 and the opening 41 is a conical shape formed Thus, a uniform and stable discharge state can be formed, and fine dust and mist can be charged uniformly.

Further, when the arrangement interval of the discharge needle electrode 80 is narrowed, there is a drawback that a repulsive force acts in the vicinity of the discharge portion and discharge to the ground electrode plate 40 is reduced. However, as described above, the round hole-shaped opening 41 is formed. more be arranged at regular intervals in a zigzag manner, while maintaining the strength of the ground electrode plate 40, it is possible to secure the opening area of the ground electrode plate 40 required, it is possible to ensure proper filtration air volume, Since a predetermined distance can be maintained between the adjacent discharge needle electrode 80, adverse effects due to interference with the adjacent discharge needle electrode 80 can be prevented.

  Next, the charging area EA of the charging device will be described by comparing the conventional charging device and the charging device 6 of the present invention with reference to FIGS. 7 to 9, 13, and 14.

  In FIG. 13, a support substrate 102 is disposed between the ground electrode plates 101 arranged side by side, and the discharge needle electrode 103 is supported along the flow direction of the dust-containing air so as to be parallel to the ground electrode plate 101. FIG. 14 is a plan view showing a charging device 100 of a conventional electrostatic precipitator supported by 102, and FIG. 14 is a front view thereof, and each shows a charging area EA by a one-dot chain line. In this case, as shown by a broken line ellipse in FIG. 14, there is a weakly charged area WA between the discharge needle electrodes 103. In order to reduce this weakly charged area WA, it has also been proposed to attach the discharge needle electrode 103 so as to be inclined in the vertical direction (see FIGS. 4 to 6 in Patent Document 1). It is difficult to cover all weak areas WA. Therefore, the conventional charging device 100 has a problem that it is difficult to improve the charging efficiency.

  On the other hand, in the charging device 6 of the electrostatic precipitator according to the above-described embodiment of the present invention, as shown in FIGS. 7 to 9, between the entire peripheral end of the opening 41 of the ground electrode plate 40. The charging area EA can be formed. In particular, when the opening 41 has a round hole shape, a conical charging area EA having a beautiful parabola drawn on the opening 41 can be formed. Therefore, the dust-containing air always passes through the opening 41, and particles such as fine dust and mist in the dust-containing air can be reliably and uniformly charged, and air ions and fine dust generated by high-voltage corona discharge can be obtained. In addition, since the efficiency of collision (contact) with mist can be increased, efficient charging can be performed.

  As a result of the experiment, when the charging device 6 of the electrostatic precipitator according to the embodiment of the present invention described above is used, the discharge of the discharge needle electrode 80 is compared with the case where the conventional charging device 100 is used. It has been found that the current can be reduced to about ½, and the power consumption can be reduced to about ½.

  Next, a modification of the charging device 6 according to the above-described embodiment of the present invention will be described with reference to FIGS. Here, FIG. 10 is a plan view showing a modification of the charging device 6 of the electrostatic precipitator according to the embodiment of the present invention, FIG. 11 is a front view showing the modification, and FIG. 12 is a side view showing the modification. is there.

  In the case of this modification, the opening 91 of the ground electrode plate 90 is formed in a substantially square shape as shown in FIG. 11, and the four corners of the opening 91 are curved. Further, the support substrate 93 is configured by integrally forming a support portion 94 made of an elongated sheet metal and a tapered triangular projection portion 95 bent from the support portion 94. The protrusions 95 are alternately bent and formed so that the tip ends thereof are located on the center line CL of the opening 91 adjacent to the left and right sides of the support substrate 63.

  As described above, when the opening 91 of the ground electrode plate 90 has a substantially rectangular shape, a larger opening area can be ensured than when the opening 91 has a round hole shape, and the amount of dust-containing air is large. Is particularly effective. Further, by making the four corners of the opening 91 R-shaped, it is possible to suppress a decrease in the discharge amount in the charging area EA (shown by a one-dot chain line in FIGS. 10 and 11) at the four corners. And accumulation of mist can also be suppressed. Moreover, by forming the support part 94 and the protrusion part 95 integrally with a sheet metal, the number of parts can be reduced and the cost can be reduced.

  As described above, according to the electric dust collector according to the embodiment of the present invention, the dust-containing air rectified by the openings 41 and 91 of the ground electrode plates 40 and 90 is not obstructed by the support substrates 60 and 93. In addition, since the ground electrode plates 40 and 90 have less adhesion and accumulation of particles such as charged fine dust and mist, the maintenance cycle can be extended, the usability can be improved, and the flow direction of the dust-containing air The dust collector 7 on the downstream side can be used effectively.

  In addition, since the above description of the embodiment of the present invention describes a preferred embodiment of the electric dust collector according to the present invention, there may be various technically preferable limitations. The technical scope of the present invention is not limited to these embodiments unless specifically described to limit the present invention. That is, the above-described components in the embodiment of the present invention can be appropriately replaced with existing components and the like, and various variations including combinations with other existing components are possible. The description of the embodiment of the present invention described above does not limit the contents of the invention described in the claims.

  The technology of the present invention is expected to be used in an electric dust collector that sucks and collects dust and oil mist generated in a processing factory.

6 Charging device 7 Dust collector 40 Ground electrode plate 41 Opening 60 Support substrate 80 Discharge needle electrode (discharge electrode)

Claims (2)

In an electrostatic precipitator equipped with a charging device that charges particles such as fine dust and mist in dusty air by corona discharge generated by the application of high voltage,
A ground electrode plate that is arranged in a direction that blocks the flow of dust-containing air and that has a large number of openings through which dust-containing air passes;
A support substrate for supporting a discharge electrode disposed corresponding to each opening of the ground electrode plate;
With
The opening has a round hole shape and is provided in the same number as the distal end of the discharge electrode, and the support substrate supports the proximal end of the discharge electrode,
The ground electrode plate is arranged apart from the discharge electrode on the upstream side in the flow direction of the dust-containing air ,
The tip of the discharge electrode is located on the center line of the opening as viewed from the flow direction of the dust-containing air, and between the tip of the discharge electrode and the peripheral edge of the opening is due to corona discharge. forming a charged area of the conical shape, the supporting substrate, when viewed from the direction of flow of air containing dust, electrostatic precipitator, characterized that you have been arranged so as not to interfere with the opening. The support substrate supports a proximal end portion of the discharge electrode so that a distal end portion of the discharge electrode and a peripheral edge portion of the opening maintain a predetermined distance, and the distal end portion of the discharge electrode includes dust-containing air. The electrostatic precipitator according to claim 1, wherein the electrostatic precipitator is bent so as to be positioned on a center line of the opening as viewed from the flow direction.

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