WO2020085231A1 - Dust removal device - Google Patents

Abstract

This dust removal device comprises: at least one nozzle that is disposed in a blow-out part for blown air, is capable of spraying a supplied liquid in the form of droplets, and is connected to ground; an electrode part that includes a counter electrode which is shaped so as to surround at least half of the circumference of one opening, with one counter electrode provided for one nozzle, and with the counter electrode being disposed so as to be separated from the nozzle in the direction in which the nozzle sprays the droplets; and a high-voltage generation device that has a ground terminal connected to ground, and that is for applying a high voltage to the counter electrode which is connected to an output terminal. If a leakage current is not flowing between the nozzle and the counter electrode, the current flowing between the nozzle and ground is no greater than 0.3 milliamperes (square meters/liter per minute) for every 1 liter per minute of droplet spray and every 1 square meter of the opening surface area of the blow-out part.

Description

Dust remover

The present disclosure relates to a dust removing device.

In order to remove fine particles such as PM (Particulate Matter) floating in the air, it is conceivable to collect the fine particles in the air by charged droplets, for example.
For example, in the air purification device described in Patent Document 1, charged water droplets can be generated by atomizing the water column discharged from the fine holes provided in the flat plate by electrostatic atomization. In the air purification device, dust or the like contained in the air can be removed by supplying the charged droplets into the room (see Patent Document 1).

JP 2006-97960A

However, in the air purification device described in Patent Document 1, it is difficult to generate a large amount of liquid droplets because the water column discharged from the fine holes provided in the flat plate is atomized by electrostatic atomization. Therefore, the air can be purified only in a relatively narrow space such as a home space or an office.

In view of the above-mentioned circumstances, at least one embodiment of the present invention aims to provide a dust remover capable of removing fine particles floating in the air in a relatively wide space.

(1) A dust removing device according to at least one embodiment of the present invention,
At least one nozzle, which is arranged at the blowout part of the blown air, is capable of ejecting the supplied liquid as droplets, and is connected to the ground;
The counter electrode includes a counter electrode having a shape surrounding at least a half circumference of one opening, and one counter electrode is provided for one of the nozzles, and the counter electrode is arranged in a direction in which the nozzle ejects a droplet. An electrode portion arranged apart from the nozzle,
A high voltage generator for applying a high voltage to the counter electrode, which has a ground terminal connected to the ground and connected to an output terminal,
Equipped with
The current flowing between the nozzle and the ground is, when a leakage current does not flow between the nozzle and the counter electrode, per injection amount of the droplet of 1 liter / min and the opening area of the blowing portion. It is less than 0.3 milliamps / (square meter liter / minute) per square meter.

As described above, in the air purification apparatus described in Patent Document 1, since the water column discharged from the fine holes provided in the flat plate is atomized by electrostatic atomization, it is difficult to generate a large amount of droplets. is there.
On the other hand, according to the above configuration (1), a relatively large amount of droplets can be generated by the nozzle. According to the configuration of (1), the electric field formed by the potential difference between the counter electrode and the grounded nozzle causes the liquid droplets ejected from the nozzle to be dielectrically polarized, and the voltage applied to the counter electrode. The droplet can be charged with a polarity opposite to that of. In this way, from the principle of charging the liquid droplets by dielectric polarization, it is not necessary to apply a current to the counter electrode to charge the liquid droplets. Further, even if the ejection amount of the droplets is increased, the charge amount due to the dielectric polarization per droplet does not decrease.
Therefore, it is possible to charge a relatively large amount of liquid droplets with a charge amount effective for collecting fine particles in the atmosphere by the high voltage generator having a relatively small output power. As a result, it is possible to efficiently collect and remove fine particles in the atmosphere with charged droplets in a relatively large space such as a gymnasium or an indoor stadium, or outdoors.
Further, according to the configuration of (1), as described above, since it is not necessary to supply a current to the counter electrode to charge the liquid droplet, a high-output high-voltage generator is not required, and a high-voltage generation is possible. The cost of the device can be suppressed.
As a result of intensive studies by the inventors, by ensuring the insulation of the counter electrode so that a leakage current does not flow between the nozzle and the counter electrode, the current flowing between the nozzle and the ground is ejected from the droplet. Even if the amount is less than 0.3 mA / (square meter liter / minute) per 1 liter / minute and per 1 square meter opening area of the air outlet, it is effective for the fine particles in the atmosphere in the above-mentioned relatively wide space and outdoors. The droplets can be charged so that they can be selectively collected.

(2) In some embodiments, in the configuration of (1) above,
The nozzle is configured to eject the droplet in a conical shape,
Regarding the relationship between the nozzle and the counter electrode, the first distance from the jetting position of the droplet in the nozzle to the intersection of the plane including the counter electrode and the center line of the cone is r (millimeter), and the intersection is When the second distance that is the minimum distance between the counter electrode and the counter electrode is a ₀ (millimeter), and the ejection angle at which the nozzle ejects the droplet is θ (degrees), the following equation (1)
r <a ₀ / tan (θ / 2) (1)
It is represented by.

According to the configuration of the above (2), when the above equation (1) is satisfied, the droplets ejected in a conical shape from the nozzle pass through the region inside the counter electrode in the opening surrounded by the counter electrode. Can be made. As a result, it is possible to prevent the counter electrode from getting wet with droplets, and it is possible to suppress the flow of leakage current between the nozzle and the counter electrode.

(3) In some embodiments, in the configuration of (2) above,
The first distance is 5 mm or more and 200 mm or less,
The second distance is 5 mm or more and 50 mm or less.

According to the configuration of (3), by setting the first distance and the second distance within the above range, the high voltage applied to the counter electrode forms the droplet at the nozzle ejection position, that is, at the nozzle tip. The strength of the applied electric field can be sufficiently increased.

(4) In some embodiments, in the configuration of (2) or (3), the ejection angle of the nozzle is 30 degrees or more and 100 degrees or less.

When the spray angle is large, the counter electrode is easily wet with the liquid droplets. Therefore, current leakage is likely to occur, and it becomes difficult to secure the electric field strength necessary for charging the droplets.
On the other hand, according to the configuration of (4), by setting the ejection angle of the nozzle to 30 degrees or more and 100 degrees or less, wetting of the counter electrode with droplets can be suppressed, and the electric field strength required for charging the droplets can be reduced. Can be secured.

(5) In some embodiments, in any one of the configurations (1) to (4), the at least one nozzle has a droplet diameter of 10 μm or more and 300 μm or less in terms of Sauter average diameter. The droplets can be ejected.

As a result of diligent studies by the inventors, it has been found that the effect of removing fine particles in the atmosphere tends to decrease as the droplet size increases.
On the other hand, with the configuration of (5) above, by setting the droplet diameter to 10 μm or more and 300 μm or less in terms of Sauter mean diameter, it is possible to effectively collect fine particles in the atmosphere with the droplets.

(6) In some embodiments, in any of the configurations of (1) to (5) above,
And a blower for blowing the air containing the droplets,
The nozzle and the electrode unit are attached to the housing of the blower.

According to the above configuration (6), the air blown from the blower can diffuse the droplets into a relatively wide space, so that dust can be removed in a relatively wide space. Further, according to the configuration of (6) above, by mounting the nozzle and the electrode portion on the housing of the blower, the nozzle and the electrode portion are installed at positions where the droplets can be effectively diffused by the air blown from the blower. It becomes easy to do.

(7) In some embodiments, in any of the configurations of (1) to (6) above,
A support portion configured by an insulating material and supporting the electrode portion,
A scavenging nozzle configured to inject a gas toward the support portion,
Is further provided.

If the supporting part gets wet with the droplet, the high-voltage current applied to the counter electrode may flow as a leakage current to the ground side via the supporting part wet with the droplet. On the other hand, according to the configuration of (7) above, by injecting gas from the scavenging nozzle toward the support portion, it is possible to suppress liquid droplets from adhering to the support portion and suppress the generation of leakage current. .

(8) In some embodiments, in any of the configurations of (1) to (7) above,
It further comprises a support portion configured to be formed of a water-repellent insulating material, or formed of an insulating material and having a surface subjected to a water-repellent treatment, for supporting the electrode portion.

As described above, if the supporting part gets wet with the liquid droplets, the high-voltage current applied to the counter electrode may flow as a leakage current to the ground side through the supporting part wet with the liquid droplets. On the other hand, according to the configuration of (8), even if the droplet contacts the supporting portion, the water repellency can prevent the droplet from adhering to the supporting portion. Further, even if the droplet contacts the supporting portion, it is possible to prevent the entire surface of the supporting portion from getting wet with the liquid. Thereby, the generation of leakage current can be suppressed.

(9) In some embodiments, in any of the configurations of (1) to (8) above,
And a blower for blowing the air containing the droplets,
A plurality of nozzles are provided on the downstream side of the blower with respect to the flow of air blown by the blower.

According to the above configuration (9), the droplets can be uniformly applied to the flow of air blown from the blower by ejecting the droplets from the plurality of nozzles.

(10) In some embodiments, in any of the configurations of (1) to (9) above,
An air blower for blowing air containing the droplets, the blower having the blowing portion;
A direction changing device configured to change the blowing direction of air from the blower,
Is further provided.

According to the configuration of (10) above, by changing the blowing direction of the air from the blower with the direction changing device, it is possible to easily change the direction in which the droplets are scattered, starting from the arrangement position of the dust removing device.

(11) In some embodiments, in any of the configurations of (1) to (10) above,
An air blower for blowing air containing the droplets, the blower having the blowing portion;
A direction changing device configured to change the blowing direction of air from the blower,
Further equipped with,
The direction changing device is configured to be able to set the air blowing direction so that the air can be blown at least above the horizontal direction.

According to the configuration of (11) above, it is possible to collect fine particles floating in the space above the floor surface by the dust removing device arranged at a low position such as the floor surface.

(12) In some embodiments, in the configuration of (10) or (11), the direction changing device is capable of setting the air blowing direction so that air can be blown upward at an elevation angle of 0 degrees or more. Has been done.

According to the configuration of (12) above, it is possible to effectively disperse the liquid droplets that drop with the passage of time at a position away from the dust removing device.

(13) In some embodiments, in the configuration according to any one of the above (10) to (12), the direction changing device sets an ejection direction of the droplet from the at least one nozzle to an air from the blower. It is configured to be changeable in the same direction as the air blowing direction of.

According to the configuration of (13) above, since the jetting direction of the droplets from the nozzle can be changed to the same blowing direction of the air from the blower, the droplets can be efficiently applied to the flow of air blown from the blower. it can.

According to at least one embodiment of the present invention, it is possible to remove fine particles suspended in the air in a relatively large space.

It is a perspective view which showed typically the external appearance of the dust remover concerning some embodiments. It is the figure which looked at the dust remover concerning some embodiments from the lower stream side of the blower's ventilation direction, and shows the important section. It is a side view of the dust remover concerning some embodiments, and shows the composition of the important section typically. It is a schematic diagram for explaining a mechanism for charging a droplet. It is a figure for demonstrating the positional relationship between a nozzle and a counter electrode. It is a figure for further explaining the 1st distance. It is the figure which looked at the dust remover concerning other embodiments from the lower stream side of the blower's ventilation direction, and shows the important section.

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative positions, and the like of the components described as the embodiments or shown in the drawings are not intended to limit the scope of the present invention thereto, but are merely illustrative examples. Absent.
For example, expressions that represent relative or absolute arrangements such as “in a certain direction”, “along a certain direction”, “parallel”, “orthogonal”, “center”, “concentric”, or “coaxial” are strict. In addition to representing such an arrangement, it also represents a state in which the components are relatively displaced by a tolerance or an angle or a distance at which the same function can be obtained.
For example, expressions such as "identical", "equal", and "homogeneous" that indicate that they are in the same state are not limited to strict equality, but also include tolerances or differences in the degree to which the same function is obtained. It also represents the existing state.
For example, the representation of a shape such as a quadrangle or a cylindrical shape does not only represent a shape such as a quadrangle or a cylindrical shape in a geometrically strict sense, but also an uneven portion or a chamfer within a range in which the same effect can be obtained. The shape including parts and the like is also shown.
On the other hand, the expressions “comprising”, “comprising”, “comprising”, “including”, or “having” one element are not exclusive expressions excluding the existence of other elements.

FIG. 1 is a perspective view schematically showing the appearance of a dust remover according to some embodiments. FIG. 2 is a view of a dust removing device according to some embodiments as seen from a downstream side in a blowing direction of a blower described later, and shows a main part. FIG. 3 is a side view of the dust remover according to some embodiments, and schematically shows the configuration of the main part.

The dust remover 1 according to some embodiments includes a blower 10, a nozzle 20, an electrode unit 30, and a high voltage generator 40.
A blower 10 according to some embodiments is a blower for blowing air including droplets 2 (see FIG. 3) ejected by a nozzle 20 described later. The blower 10 according to some embodiments includes an impeller 12 that is rotated by a driving force of a motor (not shown) inside a casing 11 having a cylindrical shape, for example, and the cylindrical casing 11 is rotated by the rotation of the impeller 12. Air is sucked in from one end and blown in from the left side to the right side in the drawing as shown by an arrow C in FIG. 3, and is discharged from the blowing section 13 at the other end.

The nozzle 20 according to some embodiments is a nozzle capable of ejecting the liquid supplied from the supply pump 29 as droplets, and is generally also called a spray nozzle. In some embodiments, the liquid supplied to the nozzle 20 is water, for example.
In some embodiments, the nozzle 20 is attached to the supply pipe 22 and arranged in the blowout air blower 13. More specifically, the nozzle 20 is arranged at a position separated from the blowout portion 13 at the other end of the housing 11 of the blower 10 on the downstream side in the blowing direction. The supply pipe 22 is attached to the housing 11 of the blower 10 by the pipe attachment portion 24.
In some embodiments, multiple nozzles 20 are provided. In the example shown in FIGS. 1 and 2, eight nozzles 20 are provided, but the number of nozzles 20 may be one or more.
In some embodiments, the nozzle 20 ejects droplets toward the downstream side of the blower 10 in the blowing direction.

The nozzle 20 according to some embodiments is configured to eject the droplet 2 in a conical shape.
The nozzle 20 according to some embodiments is configured to be capable of ejecting a droplet having a droplet diameter of 10 (μm) or more and 300 (μm) or less in average Sauter diameter.
Further, the ejection angle θ of the nozzle 20 according to some embodiments is 30 degrees or more and 100 degrees or less. The droplet diameter and the spray angle θ will be described in detail later.

The nozzle 20 according to some embodiments is connected to the ground 9. Specifically, the nozzle 20 according to some embodiments is connected to the ground 9 via the supply pipe 22, for example, by connecting the supply pipe 22 to the ground 9. The nozzle 20 and the supply pipe 22 are formed of a conductive member such as metal.

The electrode unit 30 according to some embodiments includes a plurality of counter electrodes 31 and an electrode support member 35 that supports the plurality of counter electrodes. Each of the counter electrodes 31 according to some embodiments has a shape surrounding the periphery of the opening 33. Each of the counter electrodes 31 according to some embodiments has, for example, an annular shape. Each of the counter electrodes 31 may have, for example, an elliptical ring shape, or may have a polygonal shape such as a rectangular shape surrounding the periphery of the opening 33. The counter electrodes 31 may have the same size or different sizes. The counter electrodes 31 may have the same shape or different shapes.
Further, each of the counter electrodes 31 does not necessarily have to have a closed shape, and may have, for example, a shape that surrounds the periphery of the opening 33 for at least a half circumference or more.

In the electrode unit 30 according to some embodiments, one counter electrode is provided for one nozzle 20.
In the electrode unit 30 according to some embodiments, a plurality of counter electrodes 31 are supported by an electrode support member 35.
In the electrode unit 30 according to some embodiments, the counter electrode 31 is arranged apart from the nozzle 20 in the direction in which the nozzle 20 ejects droplets, and is supported by the support unit 51 made of an insulating material. Specifically, one end of the columnar support portion 51 is fixed to the mounting portion 15 provided at the other end of the casing 11 of the blower 10, and the electrode support member 35 of the electrode portion 30 is fixed to the other end of the support portion 51. Has been done.

The high voltage generator 40 according to some embodiments is a device capable of generating a high voltage of, for example, 1 kilovolt or more. In the high voltage generator 40 according to some embodiments, the ground terminal 42 is connected to the ground 9, and a high voltage can be applied to the counter electrode 31 (electrode portion 30) connected to the output terminal 41.

In the dust remover 1 according to some embodiments, the blower 10 is supported by the blower support portion 61 so as to be able to rise and fall, as indicated by an arrow A in FIG. 1. In the dust remover 1 according to some embodiments, the blower 10 is rotatable about the central axis CL by the turning device 65 as shown by an arrow B in FIG. 1. That is, the blower 10 can rotate in a plane parallel to the mounting surface of the turning device 65, such as the floor.
That is, in the dust removing device 1 according to some embodiments, the direction changing device 60 configured to change the blowing direction of the air from the blower includes the blower support portion 61 and the turning device 65.

In the dust remover 1 according to some embodiments configured as described above, the liquid (water) supplied from the supply pump 29 can be sprayed as droplets by the plurality of nozzles 20. Then, in the dust removing device 1 according to some embodiments, by applying the high voltage generated by the high voltage generating device 40 to the counter electrode 31, the droplet 2 sprayed from the nozzle 20 is applied to the counter electrode 31. It can be charged to the opposite polarity of the applied voltage.
Further, in the dust removing device 1 according to some embodiments, it is possible to diffuse the charged droplets 2 to the surroundings by blowing air from the blower 10 in a relatively large space such as a gymnasium or an indoor stadium or outdoors. it can.
The charged droplets 2 can collect fine powder in the air by electrostatic force. The fine powder collected in the droplet 2 falls on the ground together with the droplet 2. Thus, for example, in a relatively large space such as a gymnasium or an indoor arena, or outdoors, fine particles in the atmosphere can be efficiently collected and removed by the charged droplets 2.

(Regarding the charging mechanism of the droplet 2)
Here, the mechanism of charging the droplet 2 in the dust removing device 1 according to some embodiments will be described. FIG. 4 is a schematic diagram for explaining the mechanism of charging the droplet 2.
When a high voltage from the high voltage generator 40 is applied to the counter electrode 31, the liquid ejected from the nozzle 20 is generated by the electric field formed by the potential difference between the counter electrode 31 and the nozzle 20 connected to the ground 9. The drop 2 is dielectrically polarized.
For example, when a negative high voltage is applied to the counter electrode 31 from the high voltage generator 40, in the droplet 2 immediately before being ejected from the nozzle 20, a region near the counter electrode 31 is positively charged, and the counter electrode 31 is charged. Areas far from 31 are negatively charged. The polarization charge induced in the region far from the counter electrode 31 flows to the ground (ground 9) through the conductive nozzle 20 and the supply pipe 22.
As a result, the droplet 2 ejected from the nozzle 20 is positively charged.
As described above, in the dust remover 1 according to some embodiments, it is possible to charge the droplet 2 sprayed from the nozzle 20 to a polarity opposite to the polarity of the voltage applied to the counter electrode 31 by dielectric polarization. it can.

(Regarding amount of generated droplet 2)
For example, when minute droplets are generated from a liquid by electrostatic atomization, it is difficult to generate a relatively large number of droplets in principle. Therefore, for example, in the case of producing fine droplets from a liquid by electrostatic atomization, for example, in a relatively large space such as a gymnasium or an indoor stadium, or outdoors, droplets obtained by charging fine particles in the atmosphere can be efficiently used. Difficult to collect and remove. In that regard, in some embodiments, a relatively large amount of droplets 2 can be produced by the nozzle 20.

Therefore, since the dust remover 1 according to some embodiments includes the nozzle 20, the electrode unit 30, and the high-voltage generator 40, a relatively large amount of the droplet 2 generated by the nozzle 20 is subjected to dielectric polarization. Can be charged by.
In the dust remover 1 according to some embodiments, it is not necessary to apply a current to the counter electrode 31 to charge the droplet 2 because of the principle of charging the droplet 2 by dielectric polarization.
Therefore, in the dust remover 1 according to some embodiments, the total value of the currents flowing from the high voltage generator 40 to all the counter electrodes 31 is the same as when the leakage current does not flow between the nozzle 20 and the counter electrode 31. In addition, it is possible to suppress it to less than 0.1 (mA), for example.

In addition, in the dust remover 1 according to some embodiments, even if the injection amount of the droplet 2 is increased, the charge amount due to the dielectric polarization per droplet does not change from the principle of charging the droplet 2 by dielectric polarization. It does not decrease.
Therefore, according to the dust remover 1 according to some embodiments, the high voltage generator 40 having a relatively low output power causes a relatively large amount of liquid with an effective charge amount for collecting fine particles in the atmosphere. The drop 2 can be charged. As a result, the particles 2 in the atmosphere can be efficiently collected and removed by the charged droplets 2 in a relatively large space such as a gymnasium or an indoor stadium or outdoors.
Further, according to the dust remover 1 according to some embodiments, as described above, since it is not necessary to pass a current through the counter electrode 31 to charge the droplet 2, the high-voltage high-voltage generator 40 has a large output. It is unnecessary, and the cost of the high voltage generator 40 can be suppressed.

That is, as described above, in the dust removers 1 according to some embodiments, in principle, it is not necessary to apply a current to the counter electrode 31 to charge the droplet 2. Therefore, by ensuring the insulation of the counter electrode 31 (electrode portion 30) so that the leakage current does not flow between the nozzle 20 and the counter electrode 31, almost all the current flowing from the high voltage generator 40 to the counter electrode 31 is generated. You can choose not to. Thereby, the rated output of the high voltage generator 40 can be reduced, and the cost of the high voltage generator 40 can be further suppressed.

FIG. 5 is a diagram for explaining the positional relationship between the nozzle 20 and the counter electrode 31. Hereinafter, the positional relationship between the nozzle 20 and the counter electrode 31 will be described.
In the dust remover 1 according to some embodiments, as described above, the nozzle 20 is configured to eject the droplet 2 in a conical shape. Therefore, in order to prevent the liquid droplets 2 ejected from the nozzle 20 from directly contacting the counter electrode 31, in the dust removers 1 according to some embodiments, the positional relationship between the nozzle 20 and the counter electrode 31 is as follows. The formula (1) described in (3) is satisfied.

That is, the first distance L1 from the tip 20a of the nozzle 20, that is, the intersection C1 of the plane including the counter electrode 31 and the center line of the cone from the tip 20a of the nozzle 20 to r1 (millimeter), the intersection C1 The second distance L2, which is the minimum distance between the counter electrode 31 and the counter electrode 31, is a ₀ (millimeter), and the ejection angle at which the nozzle 20 ejects the droplet 2 is θ (degrees). The relationship is expressed by the following equation (1).
r <a ₀ / tan (θ / 2) (1)

When the above formula (1) is satisfied, the droplet 2 that is conically ejected from the nozzle 20 can pass through the region inside the counter electrode 31 in the opening 33 surrounded by the counter electrode 31. As a result, it is possible to prevent the counter electrode 31 from getting wet with the liquid droplet 2, and it is possible to prevent a leakage current from flowing between the nozzle 20 and the counter electrode 31.

The ejection angle of the nozzle 20 is preferably 30 degrees or more and 100 degrees or less, as described above.
That is, when the spray angle is large, the counter electrode 31 is likely to be wet with the droplet 2. Therefore, current leakage is likely to occur, and it becomes difficult to secure the electric field strength necessary for charging the droplets.
Therefore, by setting the ejection angle of the nozzle 20 to 30 degrees or more and 100 degrees or less, it is possible to prevent the counter electrode 31 from getting wet with the droplet 2 and to secure the electric field strength necessary for charging the droplet.

Note that, for example, when the housing 11 has an inner diameter of about 300 (mm) and about eight nozzles 20 are provided, the second distance L2, which is the minimum distance between the intersection C1 and the counter electrode 31, is 5 (mm). It is better to be 50 (mm) or less. In this case, the first distance L1 from the tip 20a of the nozzle 20 to the intersection C1 is preferably 5 (mm) or more and 200 (mm) or less. When the counter electrode 31 has an annular shape, the second distance L2 is the inner radius of the counter electrode 31.

(About the first distance L1)
FIG. 6 is a diagram for further explaining the first distance L1.
The greater the amount of polarization charge induced in the droplet 2, the more efficiently the droplet collects fine powder in the atmosphere. Therefore, it is preferable to determine the positional relationship between the nozzle 20 and the counter electrode 31 so that the electric field strength formed in the vicinity of the outlet (tip 20a) of the nozzle 20 with respect to the voltage applied to the counter electrode 31 is as large as possible.

The electric field strength formed at the tip 20a of the nozzle 20 is generally expressed by the following equation (2), and when the inner radius and the outer radius of the counter electrode 31 are determined, the electric field strength becomes a maximum value. The distance (first distance L1) is determined.
E = −r / (a−a ₀ )
× {1 / (a ² + r ² ) ^0.5 −1 / (a ₀ ² + r ² ) ^0.5 } × V ₀ (2)
Here, a is the outer radius L3 (m) of the counter electrode 31, and a ₀ is the inner radius L2 (m) of the counter electrode 31 as described above. r is the first distance L1 (m) from the tip 20a of the nozzle 20 to the intersection C1 as described above. V ₀ is a voltage (V) applied to the counter electrode. E is the electric field intensity (V / m) at the tip 20a of the nozzle 20.

Therefore, it is preferable to determine the first distance L1 so that the electric field strength E is as close to the maximum value as possible within the range of 5 (mm) or more and 200 (mm) or less based on the above equation (2). The applied voltage V ₀ is preferably 5 (kV) or more and 80 (kV) or less.

In the dust remover 1 according to some embodiments, by setting the first distance L1 and the second distance L2 within the above range, the droplet ejection position in the nozzle 20 by the high voltage applied to the counter electrode 31, That is, the strength of the electric field formed at the tip 20a of the nozzle 20 can be sufficiently increased.
If the first distance L1 does not fall within the above range due to, for example, the insulating structure of the electrode portion 30, the inner radius and the outer radius of the counter electrode 31 are adjusted so that the electric field strength E becomes equal to the first distance. It is good to make it maximum with respect to L1.

(About droplet size)
As described above, the nozzle 20 according to some embodiments is configured to be capable of ejecting a liquid droplet having a Sauter mean diameter of 10 (μm) or more and 300 (μm) or less.
As a result of diligent studies by the inventors, it has been found that the effect of removing fine particles in the atmosphere tends to decrease as the droplet size increases. If the droplet diameter is too small, the droplet 2 will evaporate before the droplet 2 reaches the ground. If the fine particles collected by the droplet 2 are a solid insoluble in water, if the droplet 2 evaporates before the droplet 2 reaches the ground, the fine particles will diffuse into the atmosphere again. I will end up.
On the other hand, in some embodiments, by setting the droplet diameter of the droplet 2 ejected from the nozzle 20 to be not less than 10 (μm) and not more than 300 (μm) in terms of Sauter average diameter, the fine particles in the atmosphere are droplets. Can be effectively collected.

Since the dust remover 1 according to some embodiments includes the blower 10, the droplets 2 can be diffused into a relatively wide space by the air blown from the blower 10, so that the dust in the relatively wide space is removed. It can be performed.
Further, in the dust remover 1 according to some embodiments, since the nozzle 20 and the electrode unit 30 are attached to the housing 11 of the blower 10, it is possible to effectively diffuse the droplets 2 by blowing air from the blower 10. It becomes easy to install the nozzle 20 and the electrode part 30 at a position where the above can be achieved.

FIG. 7 is a view of a dust removing device according to another embodiment as viewed from the downstream side of the blower in the blowing direction, and shows the main part. In the dust remover 1 according to another embodiment, a scavenging nozzle 71 is further provided in addition to the dust removers 1 according to some of the above-described embodiments. The scavenging nozzle 71 is a nozzle configured to be able to inject gas toward the support portion 51 that supports the electrode portion 30. In the dust removing device 1 according to another embodiment shown in FIG. 7, the scavenging nozzle 71 is arranged on the outer side in the radial direction of the housing 11 with respect to the support portion 51, and as shown by an arrow b, the housing is shown. Gas can be ejected from the outside of the body 11 in the radial direction toward the inside. In the dust remover 1 according to another embodiment shown in FIG. 7, two scavenging nozzles 71 are arranged for one support portion 51, but if at least one scavenging nozzle 71 is arranged. Good.

When the support portion 51 gets wet with the droplet 2, the high-voltage current applied to the counter electrode 31 is leaked to the ground side via the support portion 51 wet with the droplet 2 and the housing 11 of the blower 10. It may flow. In that respect, according to the dust removing device 1 according to another embodiment shown in FIG. 7, the droplet 2 is attached to the support portion 51 by injecting gas from the scavenging nozzle 71 toward the support portion 51. It is possible to suppress the occurrence of leakage current.
Note that the scavenging nozzle 71 may be provided for all of the supporting portions 51, or may be provided only for the supporting portion 51 that is easily wetted in the most frequently used postures among the postures of the blower 10. Good.

In some of the embodiments shown in FIGS. 2 and 7, the support portion 51 is made of a water-repellent insulating material, or is made of an insulating material and the surface thereof is subjected to a water-repellent treatment. It is good to have Accordingly, even if the droplet 2 comes into contact with the support portion 51, it is possible to suppress the droplet 2 from adhering to the support portion 51 due to its water repellency. Further, even if the droplet 2 comes into contact with the support portion 51, it is possible to prevent the entire surface of the support portion 51 from getting wet with the liquid. Thereby, the generation of leakage current can be suppressed.

In the dust remover 1 according to some embodiments, a plurality of nozzles 20 are provided on the downstream side of the blower with respect to the flow of air blown by the blower 10.
Accordingly, by ejecting the droplets 2 from the plurality of nozzles 20, the droplets 2 can be uniformly applied to the flow of air blown from the blower 10.
Here, as a result of intensive studies by the inventors, it has been found that the flow velocity of the blown air blown out from the blowout portion 13 of the blower 10 is preferably 5 (m / sec) or more. Since the ejection speed of the droplet 2 from the nozzle 20 is approximately 5 (m / sec) to 10 (m / sec), the flow velocity of the blown air blown out from the blowing portion 13 is equal to that of the liquid ejected from the nozzle 20. The ejection speed of the droplet 2 is preferably 0.5 times or more.

The dust remover 1 according to some embodiments includes a direction changing device 60 configured to change the blowing direction of air from the blower.
Therefore, by changing the blowing direction of the air from the blower 10 by the direction changing device 60, it is possible to easily change the direction in which the droplets 2 are scattered, with the arrangement position of the dust removing device 1 as the starting point.

In the dust removing device 1 according to some embodiments, the direction changing device 60 may be configured to be able to set the air blowing direction so that the air can be blown at least above the horizontal direction.
Thereby, for example, the dust removing device 1 arranged at a low position on the floor or the like can collect fine particles floating in the space above the floor.

In the dust remover 1 according to some embodiments, the direction changing device 60 is configured to be able to set the air blowing direction so that the air can be blown upward at an elevation angle of 0 degrees or more, more preferably, an elevation angle of 30 degrees or more. It is good to have been.
This makes it possible to effectively disperse the droplets 2 that drop with the passage of time at a position away from the dust removing device 1.

In the dust removing device 1 according to some embodiments, the direction changing device 60 is configured to be able to change the ejection direction of the droplet 2 from the nozzle 20 to the same direction as the blowing direction of the air from the blower 10. That is, in the dust remover 1 according to some embodiments, the plurality of nozzles 20 are attached to the housing 11 of the blower 10 via the supply pipe 22 and the pipe attachment portion 24. In the dust removing device 1 according to some embodiments, the direction changing device 60 can change the posture of the housing 11 of the blower 10.
Therefore, the jetting direction of the droplet 2 from the nozzle 20 can be changed to the same blowing direction of the air from the blower 10, so that the droplet 2 can be efficiently applied to the flow of air blown from the blower 10.

(About the value of the current flowing between the nozzle 20 and the ground 9)
As described above, in the dust removing devices 1 according to some embodiments, it is not necessary to apply a current to the counter electrode 31 in order to charge the droplet 2 because of the principle that the droplet 2 is charged by dielectric polarization. However, the polarization charge induced in the region far from the counter electrode 31 in the droplet 2 immediately before being ejected from the nozzle 20 flows to the ground (ground 9) via the conductive nozzle 20 and the supply pipe 22. Thus, the value of the current flowing between the nozzle 20 and the ground 9 is as follows, for example.

In addition, in the dust remover 1 according to some of the embodiments, as a result of intensive studies by the inventors, it was found that the numerical ranges of the following parameters should be within the following ranges.
(A) The spray amount of the liquid may be 0.01 (l / min) or more per region 1 (m ³ ) where the fine particles are removed.
(B) The electric field strength formed at the tip 20a of the nozzle 20 is preferably 0.5 (kV / cm) or more and 10 (kV / cm) or less.
(C) As described above, the droplet diameter of the droplet 2 is preferably 10 (μm) or more and 300 (μm) or less in terms of Sauter average diameter.

An example of the value of the current flowing between the nozzle 20 and the ground 9 under the following conditions will be calculated with reference to the above range. It should be noted that the values of the parameters listed in 1) to 3) below are values appropriately adopted to calculate the value of the current flowing between the nozzle 20 and the ground 9, and the values of the respective parameters in the present invention are , And is not limited to the following values.
1) Amount of liquid (water) sprayed: 9 (l / min)
2) Electric field intensity formed at the tip 20a of the nozzle 20: 4.7 (kV / cm) = 4.7 × 10 ⁵ (V / m)
3) Droplet diameter: 80 (μm)
4) relative permittivity of water: 75
5) Water density: 1000 (kg / m ³ ).

When no leakage current flows between the nozzle 20 and the counter electrode 31, the value of the current flowing between the nozzle 20 and the ground 9 is equal to the amount of charge carried by the droplet 2 per unit time. . Therefore, the amount of electric charge carried by the droplet 2 per unit time is obtained as follows.
First, the number Np of droplets 2 sprayed per unit time can be calculated by the following equation (3).
Np = 9 / {4/3 × π × (40 × 10 ⁻⁶ ) ³ × 1000}
= 3.36 × 10 ¹⁰ (pieces / min) (3)

The charge amount Qp possessed by one droplet 2 is the product of the polarization charge amount q per unit area and the surface area s of the water droplet (Qp = q × s).
The polarization charge amount q per unit area when the droplet 2 is assumed to be a sphere is expressed by the following equation (4).
q = 3 × ε ₀ × E × (ε _s −1) / (ε _s +2) (4)
Here, ε ₀ is the dielectric constant in vacuum, and ε ₀ = 8.854 × 10 ⁻¹² (F / m). ε _s is the relative permittivity of the droplet 2 (water), and as described above, ε _s = 75. Further, as described above, E is the electric field strength formed at the tip 20a of the nozzle 20, and E = 4.7 × 10 ⁵ (V / m).
Therefore, the charge amount Qp of one droplet 2 is the product of the polarization charge amount q per unit area and the surface area s of one droplet 2, and is given by the following equation (5).
Qp = q × s
= 3 × ε ₀ × E × (ε _s −1) / (ε _s +2) × s
= 3 × 8.854 × 10 ⁻¹² × 4.7 × 10 ⁵
× (75-1) / (75 + 2) × 4 × π × (40 × 10 ⁻⁶ ) ²
= 2.41 × 10 ⁻¹³ (C) (5)

Therefore, the amount of charge (Np × Qp) that the droplet 2 sprayed per unit time has is given by the following equation (6).
Np × Qp = 8.11 × 10 ⁻³ (C / min)
= 1.35 × 10 ^-4 (C / sec)
= 0.135 (mA) (6)

Since this charge amount (Np × Qp) is a value when the spray amount is 9 (l / min), it is 0.015 (mA) when converted per spray amount 1 (l / min).

The value of this current (0.015 (mA)) represents the amount of charge carried by the droplets 2 sprayed at a spray rate of 1 (l / min) as a current. Further, since the droplet 2 is diffused into the atmosphere by the blown air blown from the blower 10, the current value calculated as described above is divided by the opening area of the blowout portion 13 of the blower 10 to obtain the blower. It is possible to obtain the apparent current density of the blown air containing the droplets 2 in the blowing portion 13 of 10.
Here, assuming that the inner diameter of the blowout portion 13 of the blower 10 is, for example, 300 (mm), the opening area Sa of the blowout portion 13 is Sa = 0.15 × 0.15 × π = 0.07 (m ² ). Become. Therefore, the apparent current density of the blown air containing the droplets 2 in the blowout portion 13 of the blower 10 is 0.015 / 0.07 = 0.214 (mA / m ² ) per spray amount 1 (l / min). ).

When the leakage current does not flow between the nozzle 20 and the counter electrode 31, the value of the current flowing between the nozzle 20 and the ground 9 is, as described above, per unit time carried by the droplet 2. Equal to the amount of charge. Therefore, by measuring the value of the current flowing between the nozzle 20 and the ground 9, the amount of charge carried by the droplet 2 per unit time can be obtained.
Furthermore, by measuring the flow rates of the liquids supplied to all the nozzles 20, the apparent current density of the blown air containing the droplets 2 in the blowout part 13 of the blower 10 can be calculated as the spray amount 1 (l / min). It can be obtained as a value around.

In the dust remover 1 according to some embodiments, in consideration of the range of the values of the parameters mentioned in (a) to (c) described above, the blown air containing the droplets 2 in the blowout unit 13 of the blower 10 is also taken into consideration. It is considered that the apparent current density may be 0.3 (mA / m ² ) or less per spray amount 1 (l / min). That is, when the leakage current does not flow between the nozzle 20 and the counter electrode 31, the current flowing between the nozzle 20 and the ground 9 is about 1 (l / min) of the ejection amount of the droplet 2 and the blowing portion. It is considered that it may be 0.3 (mA / (m ² · l / min) or less per opening area 1 (m ² ) of 13.

In this manner, by ensuring the insulation of the counter electrode 31 so that the leakage current does not flow between the nozzle 20 and the counter electrode 31, the current flowing between the nozzle 20 and the ground 9 causes the droplet ejection amount 1 Even if it is 0.3 mA / (mA / (m ² · l / min) or less per (l / min) and the opening area 1 (m ² ) of the blowout portion 13, for example, in a gymnasium or an indoor stadium. The droplets can be charged so as to effectively collect fine particles in the atmosphere in such a relatively large space or outdoors.

(In case of giving electric charge to the droplet 2 by corona discharge)
In the above description, the case where a charge is applied to the droplet 2 by dielectric polarization has been described. Therefore, it is examined below what kind of discharge conditions are required in the case of applying charges to the droplet 2 by corona discharge.
For example, as described above, a condition under which a charge of Qp = 2.41 × 10 ⁻¹³ (C) can be given to one drop having a drop diameter of 80 (μm) will be examined.

According to "Statician Handbook", Ohmsha, ed., Published by Ohmsha, ed., 1981, 1st edition, pp. 268-269, the above-mentioned electric field strength (4. 7 (kV / cm)), it is considered difficult to give 2.41 × 10 ⁻¹³ (C) charges to one droplet having a droplet diameter of 80 (μm).
In order to give 2.41 × 10 ⁻¹³ (C) charges to one droplet having a droplet diameter of 80 (μm), a higher electric field strength is required, and the electric field strength is generally 5.5. (KV / cm), and it is necessary to retain the droplets for about 0.01 (sec) in the area where the current density is 10 (mA / m ² ). When the ejection speed of the liquid droplets from the nozzle is approximately 5 (m / sec) to 10 (m / sec) as described above, one discharge electrode for performing corona discharge and the other discharge electrode are used. The retention time can be secured by setting the interval of 50 to 100 (mm) and ejecting droplets from one discharge electrode side toward the other discharge electrode side.

The current density (10 (mA / m ² )) needs to be the above in the cross section where the droplets are sprayed. For example, in the dust remover 1 according to some of the above-described embodiments, the counter electrode 31 is replaced with one discharge electrode for performing corona discharge, and the other discharge electrode for performing corona discharge is arranged in the blowing portion 13. Imagine a case. In this case, the current density (10 (mA / m ² )) is at least in the region between the discharge electrodes, in the region where the blowout portion 13 is projected when the blowout portion 13 is viewed from the downstream side in the blowing direction. It is necessary to be As described above, assuming that the inner diameter of the blowing portion 13 is 300 (mm), the opening area Sa of the blowing portion 13 is 0.07 (m ² ). Therefore, the current value flowing between the discharge electrodes is at least 10 (mA / m ² ) × 0.07 (m ² ) = 0.7 (mA).

The present invention is not limited to the above-described embodiments, and includes forms obtained by modifying the above-described embodiments, and forms obtained by appropriately combining these forms.

DESCRIPTION OF SYMBOLS 1 Dust remover 2 Droplet 10 Blower 11 Housing 20 Nozzle 30 Electrode part 31 Counter electrode 33 Opening 40 High voltage generator 51 Support part 60 Direction changing device 71 Scavenging nozzle

Claims (13)

At least one nozzle, which is arranged at the blowout part of the blown air, is capable of ejecting the supplied liquid as droplets, and is connected to the ground;
The counter electrode includes a counter electrode having a shape surrounding at least a half circumference of one opening, and one counter electrode is provided for one of the nozzles, and the counter electrode is arranged in a direction in which the nozzle ejects a droplet. An electrode portion arranged apart from the nozzle,
A high voltage generator for applying a high voltage to the counter electrode, which has a ground terminal connected to the ground and connected to an output terminal,
Equipped with
The current flowing between the nozzle and the ground is, when a leakage current does not flow between the nozzle and the counter electrode, per injection amount of the droplet of 1 liter / min and the opening area of the blowing portion. A dust remover with a rate of 0.3 milliamps / (square meter liter / minute) or less per square meter. The nozzle is configured to eject the droplet in a conical shape,
Regarding the relationship between the nozzle and the counter electrode, the first distance from the jetting position of the droplet in the nozzle to the intersection of the plane including the counter electrode and the center line of the cone is r (millimeter), and the intersection is When the second distance that is the minimum distance between the counter electrode and the counter electrode is a ₀ (millimeter), and the ejection angle at which the nozzle ejects the droplet is θ (degrees), the following equation (1)
r <a ₀ / tan (θ / 2) (1)
Represented by
The dust remover according to claim 1. The first distance is 5 mm or more and 200 mm or less,
The second distance is 5 mm or more and 50 mm or less,
The dust remover according to claim 2. The jet angle of the nozzle is 30 degrees or more and 100 degrees or less,
The dust remover according to claim 2 or 3. 5. The dust remover according to claim 1, wherein the at least one nozzle is configured to be capable of ejecting the droplets having a droplet diameter of 10 μm or more and 300 μm or less in average Sauter diameter. apparatus. And a blower for blowing the air containing the droplets,
The dust remover according to any one of claims 1 to 5, wherein the nozzle and the electrode portion are attached to a casing of the blower. A support portion configured by an insulating material and supporting the electrode portion,
A scavenging nozzle configured to inject a gas toward the support portion,
The dust removing device according to claim 1, further comprising: 8. A support part for supporting the electrode part, which is made of a water-repellent insulating material or is made of an insulating material and whose surface is subjected to a water-repellent treatment. The dust remover according to item 1. And a blower for blowing the air containing the droplets,
The dust remover according to any one of claims 1 to 8, wherein a plurality of the nozzles are provided on a downstream side of the blower with respect to a flow of air blown by the blower. An air blower for blowing air containing the droplets, the blower having the blowing portion;
A direction changing device configured to change the blowing direction of air from the blower,
The dust remover according to any one of claims 1 to 9, further comprising: An air blower for blowing air containing the droplets, the blower having the blowing portion;
A direction changing device configured to change the blowing direction of air from the blower,
Further equipped with,
The dust removing device according to claim 1, wherein the direction changing device is configured to be able to set the air blowing direction so as to blow air at least above a horizontal direction. The dust removing device according to claim 10 or 11, wherein the direction changing device is configured to be able to set the air blowing direction so that air can be blown upward with an elevation angle of 0 degrees or more. 13. The direction changing device is configured to be capable of changing a jetting direction of the droplet from the at least one nozzle to the same direction as a blowing direction of air from the blower. The dust removing device described.

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