JP2019093345A - Electrostatic atomizer - Google Patents

Abstract

To stably spray a liquid of a sufficient quantity.SOLUTION: An electrostatic atomizer 1 comprises: a liquid tank 10 for accommodating a liquid 2; an ejection plate 20 having plural openings 27 for ejecting the liquid 2; a counter electrode 30 which is so located as to face the plural openings 27; and a voltage application part 40 which applies a prescribed voltage between the liquid 2 and the counter electrode 30. The ejection plate 20 has an electrode support plate 21, and plural discharge electrodes 26 supported by the electrode support plate 21. Each of the plural discharge electrodes 26 projects from the electrode support plate 21 toward the counter electrode 30, and has an opening 27 at a tip thereof. A distance p between adjacent two discharge electrodes 26 among the plural discharge electrodes 26 is 10 times or more of an outer diameter R of each of said two discharge electrodes 26.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an electrostatic atomizer.

  Conventionally, there is known a technique of atomizing and spraying a liquid by using electrostatic force generated in the liquid by applying a high voltage to the liquid (see, for example, Patent Document 1).

JP 2004-358359 A

  However, the above prior art has a problem that the amount of liquid to be atomized is insufficient.

  Therefore, an object of the present invention is to provide an electrostatic atomizer capable of stably spraying a sufficient amount of atomized liquid.

  In order to achieve the above object, an electrostatic atomizer according to an aspect of the present invention comprises a liquid tank for containing a liquid, a jet plate having a plurality of openings for jetting the liquid, and a plurality of the plurality of jet plates. And a voltage application unit for applying a predetermined voltage between the liquid and the opposite electrode, wherein the ejection plate is supported by a flat plate portion and the flat plate portion. A plurality of cylindrical portions, each of the plurality of cylindrical portions protrudes from the flat plate portion toward the counter electrode, and has the opening at the tip, and the plurality of cylindrical portions Among them, the distance between two adjacent cylindrical portions is at least 10 times the outer diameter of each of the two cylindrical portions.

  According to the electrostatic atomizer according to the present invention, a sufficient amount of atomized liquid can be stably sprayed.

It is a perspective view showing the composition of the electrostatic atomizer concerning an embodiment. It is sectional drawing which shows the positional relationship of the several discharge electrode of an electrostatic atomizer concerning embodiment, and a counter electrode. It is a top view which shows the planar layout of the several discharge electrode of the electrostatic atomizer which concerns on embodiment. It is a figure which shows the relationship between the distance between the discharge electrodes of the electrostatic atomizer concerning embodiment, and a tailor cone. It is a figure which shows the relationship between the distance between discharge electrodes of the electrostatic atomizer concerning embodiment, and the gradient of the voltage by increase of the number of discharge electrodes. It is a figure which shows the relationship between the number of discharge electrodes of the electrostatic atomizer concerning embodiment, a dielectric breakdown voltage, and electrostatic atomization voltage. It is a figure which shows the relationship between the distance between electrodes of the electrostatic atomization voltage which concerns on embodiment, a dielectric breakdown voltage, and an electrostatic atomization voltage. It is sectional drawing which shows the positional relationship of the several discharge electrode of the electrostatic atomizer concerning the modification of embodiment, and a counter electrode.

  Below, the electrostatic atomizer concerning embodiment of this invention is demonstrated in detail using drawing. Each embodiment described below shows one specific example of the present invention. Therefore, numerical values, shapes, materials, components, arrangements and connection forms of components, steps, order of steps, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. Therefore, among the components in the following embodiments, components that are not described in the independent claims indicating the highest concept of the present invention are described as optional components.

  Further, each drawing is a schematic view, and is not necessarily illustrated exactly. Therefore, for example, the scale and the like do not necessarily match in each figure. Further, in each of the drawings, substantially the same configuration is given the same reference numeral, and overlapping description will be omitted or simplified.

  Further, in the present specification, the term indicating the relationship between elements such as vertical or equal, the term indicating the shape of an element such as a circle or a cylinder, and the numerical range are not expressions expressing only a strict meaning. This expression is meant to include a substantially equivalent range, for example, a difference of about several percent.

Embodiment
[Constitution]
First, the configuration of the electrostatic atomizer according to the present embodiment will be described with reference to FIGS. 1 and 2.

  FIG. 1 is a perspective view showing the configuration of the electrostatic atomizer 1 according to the present embodiment. As shown in FIG. 1, the electrostatic atomizer 1 according to the present embodiment includes a liquid tank 10, a jet plate 20, a counter electrode 30, a voltage application unit 40, a pump 50, and a controller 60. Prepare. The ejection plate 20 includes an electrode support plate 21 and a plurality of discharge electrodes 26.

  In FIG. 1, the controller 60 is represented as a functional block. The controller 60 is realized by, for example, a microcomputer (micro controller) or the like, and is disposed inside an outer casing (not shown) of the electrostatic atomization device 1. The controller 60 may be attached to the outside of the liquid tank 10, for example.

  FIG. 2 is a cross-sectional view showing the positional relationship between the plurality of discharge electrodes 26 and the counter electrode 30 of the electrostatic atomizer 1 according to the present embodiment. Specifically, FIG. 2 is a cross section taken along line II-II in FIG. 1 and shows a cross section passing through the central axis J of each of two adjacent discharge electrodes 26.

  The electrostatic atomization device 1 is a spray device that atomizes the liquid 2 and ejects it. Specifically, the electrostatic atomizer 1 applies a high voltage to the liquid 2 to generate an electrostatic force, and the generated electrostatic force makes the liquid 2 fine and atomizes.

  In the present embodiment, as shown in FIG. 2, the electrostatic atomizer 1 guides the liquid 2 contained in the liquid tank 10 to the tip of each of the plurality of discharge electrodes 26, and an opening provided at the tip The liquid 2 is atomized from 27 and spouts. Specifically, when the voltage application unit 40 applies a high voltage between the plurality of discharge electrodes 26 and the counter electrode 30, the electric field is concentrated on each tip of the plurality of discharge electrodes 26. The liquid 2 which has exited from the opening 27 through the inside of the discharge electrode 26 is changed in shape by the electric field to form the tailor cone 3. As the liquid 2 is refined at the tip of the tailor cone 3, mist 4 is generated. The mist 4 generated at the tip of each of the plurality of discharge electrodes 26 is discharged toward the counter electrode 30 and is discharged to the outside through the through hole 31 provided in the counter electrode 30. As shown in FIG. 2, since the mist 4 is released from each of the plurality of discharge electrodes 26, the electrostatic atomizer 1 according to the present embodiment sprays a sufficient amount of the atomized liquid 2 Can.

The liquid 2 is, for example, functional water. Functional water is an aqueous solution that has acquired reproducible and useful functions by artificial treatment, and whose scientific basis for treatment and function has been clarified, and is about to be clarified . Specifically, the functional water is electrolytic water such as hypochlorous acid water or ozone water. In the present embodiment, the liquid 2 is an aqueous solution containing an electrolyte, but it is not limited to this. The liquid 2 may be pure water or an alcohol solution. The electric conductivity of the liquid 2 is 1 μS / cm or more and 10 ⁵ μS / cm or less.

  The mist 4 is, for example, a collection of fine liquid particles having a diameter of nanometer order or micrometer order. For example, the diameter of liquid particles constituting the mist 4 is 10 nm or more and 1 μm or less.

  The electrostatic atomization device 1 according to the present embodiment is used for various devices according to the function of the liquid 2. For example, when the liquid 2 has sterilization or sterilization performance, the electrostatic atomization device 1 is used for a sterilization device or a sterilization device. Alternatively, the electrostatic atomization device 1 may be used as a humidifier or the like.

  Below, the detail of each component with which the electrostatic atomization apparatus 1 is provided is demonstrated.

  The liquid tank 10 is a container for containing the liquid 2. The liquid tank 10 is formed using, for example, a metal material such as stainless steel, but may be formed using a resin material. At this time, the liquid tank 10 may be formed using a material having acid resistance or alkali resistance or both of them depending on the property of the liquid 2.

  The shape of the liquid tank 10 is, for example, a rectangular solid whose upper surface is open, but is not limited thereto. The shape of the liquid tank 10 may be cubic or cylindrical, or may be a flat tray. In the present embodiment, the open upper surface of the liquid tank 10 is covered by the ejection plate 20. Specifically, the liquid tank 10 and the ejection plate 20 are combined to form a closed container so that the liquid 2 does not leak from other than the opening 27 of the discharge electrode 26. The liquid tank 10 is connected to a functional water reservoir or generator (not shown) via a pump 50 and a pipe 51.

  The ejection plate 20 has a plurality of openings 27 for ejecting the liquid 2. Specifically, the ejection plate 20 includes an electrode support plate 21 which is an example of a flat plate portion, and a plurality of discharge electrodes 26 which are an example of a plurality of cylindrical portions. A plurality of openings 27 are provided at the tip of each of the discharge electrodes 26.

  The electrode support plate 21 is a plate-like member that supports the plurality of discharge electrodes 26. The electrode support plate 21 is formed of, for example, a resin material, but may be formed of a metal material. At this time, the electrode support plate 21 may be formed using a material having acid resistance, alkali resistance, or both of them depending on the property of the liquid 2.

  A plurality of discharge electrodes 26 are fixed to the electrode support plate 21 by press-fitting. For example, through holes are provided in the electrode support plate 21 at positions where the plurality of openings 27 are to be provided, and the discharge electrodes 26 are inserted and fixed in the through holes. The electrode support plate 21 is a flat plate having a uniform thickness, but is not limited to this and may be a curved plate.

  The electrode support plate 21 is fixed to the liquid tank 10. The electrode support plate 21 may be formed integrally with the liquid tank 10 using the same material as the liquid tank 10.

  The plurality of discharge electrodes 26 are an example of a plurality of cylindrical portions supported by the electrode support plate 21. Each of the plurality of discharge electrodes 26 protrudes from the electrode support plate 21 toward the counter electrode 30. Each of the plurality of discharge electrodes 26 has an opening 27 at its tip. Further, as shown in FIG. 2, each of the plurality of discharge electrodes 26 has an opening 28 at the rear end, and has a flow passage 29 extending from the opening 28 to the opening 27.

  The tip of the discharge electrode 26 is the plus side in the direction from the electrode support plate 21 to the counter electrode 30. That is, the tip of the discharge electrode 26 is the portion closest to the counter electrode 30 of the discharge electrode 26. The rear end of the discharge electrode 26 is an end opposite to the front end.

  In the present embodiment, the plurality of discharge electrodes 26 have the same configuration. The shape of the discharge electrode 26 is a cylindrical shape having uniform inner diameter r and outer diameter R. Specifically, the shapes of the opening 27 and the opening 28 are respectively circular. The shape of the flow path 29 is a cylindrical shape having a uniform flow area. The inner diameter r is, for example, 0.3 mm, and the outer diameter R is, for example, 0.5 mm, but is not limited thereto. For example, the outer diameter R may be in the range of 0.5 mm to 1.5 mm.

  Note that at least one of the inner diameter r and the outer diameter R of the discharge electrode 26 may be gradually reduced from the rear end toward the front end. For example, the opening 27 on the front end side of the opening 28 on the rear end side may be smaller, and the shape of the flow path 29 may be a truncated cone.

  The rear end of the discharge electrode 26 is located at a position in contact with the liquid 2. Specifically, the rear end of the discharge electrode 26 is located inside the liquid tank 10. Thereby, the liquid 2 is led from the opening 28 on the rear end side of the discharge electrode 26 through the flow path 29 in the discharge electrode 26 to the opening 27 on the front end side.

  The discharge electrode 26 is provided vertically to the main surface 22 of the electrode support plate 21. The main surface 22 is a surface facing the counter electrode 30 of the electrode support plate 21, and is a surface on the opposite side to the liquid 2. In the present embodiment, the discharge electrode 26 has a ratio of height h to outer diameter R (hereinafter referred to as an aspect ratio) of 4 or more. That is, h ≧ 4R is satisfied. Here, the height h of the discharge electrode 26 is represented by the distance from the tip of the discharge electrode 26 to the main surface 22 as shown in FIG. The height h is, for example, 2 mm or more.

  As the aspect ratio of the discharge electrode 26 is larger, the electric field tends to be concentrated at the tip of the discharge electrode 26. Therefore, the aspect ratio of the discharge electrode 26 may be 6 or more. According to the study of the present inventors, it was confirmed that when the aspect ratio is 4 or more, the shape of the tailor cone 3 is stable and the spray amount of the mist 4 is stable. On the other hand, it was confirmed that the shape of the tailor cone 3 becomes unstable when the aspect ratio is smaller than 4.

  The discharge electrode 26 has conductivity, and is formed using, for example, a metal material such as stainless steel. At this time, the discharge electrode 26 may be formed using a material having acid resistance or alkali resistance or both of them depending on the property of the liquid 2.

  As shown in FIG. 2, among the plurality of discharge electrodes 26, the distance p between two adjacent discharge electrodes 26 is ten or more times the outer diameter R of each of the two discharge electrodes 26. That is, p ≧ 10R is satisfied. In the present embodiment, since the outer diameter R is 0.5 mm, the distance p is, for example, 5 mm or more. In the present embodiment, two adjacent discharge electrodes 26 are one discharge electrode 26 and the discharge electrode 26 closest to the one discharge electrode 26.

  Here, the distance p is the distance between the centers of two adjacent discharge electrodes 26. In FIG. 2, the central axis J of the discharge electrode 26 is illustrated. The distance p is the distance between the two central axes J. The central axis J is an imaginary axis passing through the centers of each of the circular opening 27 and the opening 28.

  The distance p may be 16 times or more of the outer diameter R. Specifically, since the outer diameter R is 0.5 mm, the distance p may be, for example, 8 mm or more. Although the details will be described later, when the distance p is 8 mm or more, stable mist 4 can be generated regardless of the number of discharge electrodes 26.

  FIG. 3 is a plan view showing a planar layout of the plurality of discharge electrodes 26 of the electrostatic atomizer 1 according to the present embodiment. In FIG. 3, the plurality of discharge electrodes 26 are represented as discharge electrodes 26 a to 26 d according to their arrangement positions. In the following description, the discharge electrodes 26 a to 26 d will be described as the discharge electrode 26 unless otherwise specified.

  As shown in FIG. 3, the electrostatic atomization device 1 includes 19 discharge electrodes 26. The number of discharge electrodes 26 is not particularly limited, and may be plural. As the number of discharge electrodes 26 increases, the amount of mist 4 generated by the electrostatic atomization device 1 can be increased. For example, the number of discharge electrodes 26 is 12 or more.

  In the present embodiment, each of the plurality of discharge electrodes 26 is arranged at a predetermined position and at an apex of one or more regular hexagons concentric with the position. Specifically, as shown in FIG. 3, the discharge electrode 26 a is located at the center of the electrode support plate 21. The remaining discharge electrodes 26 are annularly disposed around the discharge electrode 26a. The discharge electrode 26a is an example of a first cylindrical portion. The discharge electrodes 26b to 26d are an example of a plurality of second cylindrical portions disposed so as to surround the discharge electrode 26a.

  Specifically, the six discharge electrodes 26b are disposed at the respective apexes of a virtual regular hexagon hg1 centered on the discharge electrode 26a. Furthermore, the six discharge electrodes 26c are disposed at each vertex of the regular hexagon hg2 centering on the discharge electrode 26a. The six discharge electrodes 26d are disposed at the midpoints of the sides of the regular hexagon hg2.

  The regular hexagon hg1 and the regular hexagon hg2 are examples of concentric regular polygons centered on the discharge electrode 26a. The regular hexagon hg2 is larger than the regular hexagon hg1. Specifically, the length of one side of the regular hexagon hg2 is twice the length of one side of the regular hexagon hg1. The length of one side of the regular hexagon hg1 is equal to the distance p shown in FIG.

  When the number of discharge electrodes 26 is 20 or more, the 20th to 37th discharge electrodes 26 are at the apex of the regular hexagon whose one side is three times the distance p and at three equal divisions of the side. Be placed. Furthermore, when the number of discharge electrodes 26 increases, they are arranged at the vertex of the regular hexagon whose side length is four times the distance p and the quadrant of the side. As described above, in the present embodiment, the plurality of discharge electrodes 26 are a predetermined position and n concentric regular hexagons centered on the position, and each side has a length p It is arranged at the vertex and n equal points of the regular hexagon of 1 to n times.

  As shown in FIG. 3, three to six discharge electrodes 26 positioned equidistantly at a distance p are positioned around any one of the 19 discharge electrodes 26. There is. That is, the plurality of adjacent discharge electrodes 26 are all located at equal distances with respect to any one discharge electrode 26. Specifically, the plurality of discharge electrodes 26 are located at each vertex of the regular hexagonal honeycomb structure. As a result, in plan view of the electrode support plate 21, the plurality of discharge electrodes 26 are dispersed and arranged so as to be uniform in the plane without being concentrated locally.

  The counter electrode 30 is disposed to be opposed to the plurality of openings 27 as shown in FIGS. 1 and 2. The counter electrode 30 has a plurality of through holes 31 corresponding to the plurality of discharge electrodes 26 one by one. In the present embodiment, counter electrode 30 is a flat plate having a uniform thickness, and through hole 31 is provided at a position passing through central axis J of each of the plurality of discharge electrodes 26. The counter electrode 30 may be a curved plate.

  The shape of the through hole 31 is a flat cylindrical shape centered on the central axis J. The through hole 31 is provided to allow the mist 4 to pass. The mist 4 spreads conically from the tip of the tailor cone 3 and is emitted as shown in FIG. For this reason, the larger the opening diameter φ of the through hole 31, the easier it is for the mist 4 to pass.

  When the through hole 31 is too large, the distance between the discharge electrode 26 and the counter electrode 30 becomes large, so that a high electric field is hardly applied to the tip of the discharge electrode 26. In addition, when the discharge electrode 26 and the counter electrode 30 are too close to each other, dielectric breakdown between the electrodes is likely to occur. The opening diameter φ of the through hole 31 is, for example, not less than 5 times and not more than 10 times the outer diameter R of the discharge electrode 26.

  In the present embodiment, the opening diameter φ of the through hole 31 is, for example, in the range of 1 mm or more and 2.25 mm or less. The inter-electrode distance L is, for example, in the range of 3 mm to 25 mm. Here, as shown in FIG. 2, an angle formed by a central axis J and a line K connecting the open end of each of the plurality of through holes 31 and the tip of the corresponding discharge electrode 26 is represented by θ. The line K is a line connecting the outer peripheral end of the tip of the discharge electrode 26 and the opening end on the lower end side of the through hole 31 in a cross section including the central axis J.

  At this time, tan θ is in the range represented by the following equation (1).

  1 mm / 25 mm = 0.04 ≦ tan θ ≦ 2.25 mm / 3 mm = 0.75 (1)

  From the equation (1), the angle θ is 3 ° or more and 37 ° or less.

  The counter electrode 30 has conductivity, and is formed using, for example, a metal material such as stainless steel. At this time, the counter electrode 30 may be formed using a material having acid resistance or alkali resistance or both of them depending on the property of the liquid 2.

  The voltage application unit 40 applies a predetermined voltage between the liquid 2 and the counter electrode 30. In the present embodiment, the voltage application unit 40 is connected to the counter electrode 30 and the liquid tank 10. Specifically, the liquid tank 10 is grounded and applies a ground potential to the liquid 2. The voltage applying unit 40 applies a predetermined voltage between the counter electrode 30 and the liquid 2 by applying a positive potential to the counter electrode 30.

  The voltage application unit 40 may be connected to each of the plurality of discharge electrodes 26 instead of the liquid tank 10. When the electrode support plate 21 is formed using a conductive material, the voltage application unit 40 may be connected to the electrode support plate 21. Alternatively, the voltage application unit 40 may be connected to the conductive pipe 51. In addition, the voltage application unit 40 may be connected to an electrode (not shown) provided at a position in contact with the liquid 2.

  The predetermined voltage applied by the voltage application unit 40 is, for example, a DC voltage of 4.5 kV to 10 kV. Alternatively, the predetermined voltage may be 3.5 kV or more and 8.5 kV or less. The predetermined voltage may be a pulse voltage, a pulsating current voltage, or an alternating voltage.

  Specifically, voltage application unit 40 is realized by a power supply circuit including a converter and the like. For example, the voltage application unit 40 generates a predetermined voltage based on the power received from an external power source such as a commercial power source and applies the voltage between the liquid 2 and the counter electrode 30.

  The pump 50 is an example of a liquid transfer device that supplies the functional water stored in the water reservoir or the functional water generated by the generator to the liquid tank 10 as the liquid 2. By adjusting the supply amount of the functional water to the liquid tank 10 by the pump, the amount of the liquid 2 guided through the inside of the discharge electrode 26 to the opening 27 is adjusted.

  For example, the pump 50 adjusts the supply amount of functional water so that the liquid 2 of 10 μL to 60 μL per hour is supplied to the opening 27 of each of the plurality of discharge electrodes 26. Thereby, when the electrostatic atomization device 1 includes N discharge electrodes 26, the mist 4 of 10 × N μL or more and 60 × N μL per hour is generated and emitted as an entire electrostatic atomization device 1 Ru.

  The pipe 51 is provided to supply functional water as the liquid 2 to the liquid tank 10. For example, the pipe 51 connects the liquid tank 10 and a functional water generating device (not shown). In the present embodiment, as shown in FIG. 1, a pump 50 is provided in the middle of the pipe 51.

  The pipe 51 is formed using, for example, a metal material such as stainless steel. At this time, the pipe 51 may be formed using a material having acid resistance or alkali resistance or both of them depending on the property of the liquid 2.

  The controller 60 controls the overall operation of the electrostatic atomization device 1. Specifically, the controller 60 controls the operation of the voltage application unit 40 and the pump 50. For example, the controller 60 controls the voltage application unit 40 to control the timing of applying a voltage between the counter electrode 30 and the liquid 2, the magnitude of the voltage, and the like. Further, the controller 60 controls the amount of functional water supplied as the liquid 2 to the liquid tank 10 by controlling the pump 50.

  The controller 60 is realized by, for example, a microcontroller. Specifically, the controller 60 is realized by a non-volatile memory in which a program is stored, a volatile memory which is a temporary storage area for executing a program, an input / output port, a processor which executes the program, or the like. The controller 60 may be realized by a dedicated electronic circuit that performs each operation.

[Distance between discharge electrodes]
Here, the relationship between the distance p between the adjacent discharge electrodes 26 and the stable generation of the mist 4 will be described with reference to FIG. FIG. 4 is a view showing the relationship between the distance p between the discharge electrodes 26 of the electrostatic atomizer 1 according to the present embodiment and the tailor cone 3.

  The generation amount of the mist 4 depends on the shape of the tailor cone 3. Specifically, if the tailor cone 3 has a stable conical shape, the mist 4 is also generated stably.

  As shown in FIG. 4, when the distance p is shorter than 5 mm, the shape of several Taylor cones of the twelve discharge electrodes 26 is broken from the cone. For this reason, in the case of p <5 mm, the mist 4 is not stably generated. FIG. 4 shows the case where the outer diameter R of the discharge electrode 26 is 0.5 mm.

  On the other hand, when the distance p is 5 mm or more, the shape of the tailor cone 3 is maintained in a conical shape at all of the twelve discharge electrodes 26. For this reason, when p 場合 5 mm or more, the mist 4 is stably generated.

  As the distance p becomes larger, interference between adjacent discharge electrodes 26 is suppressed. Therefore, a high electric field is easily generated at the tip of each of the plurality of discharge electrodes 26, and the shape of the tailor cone 3 is stabilized. For example, when the distance p is 8 mm or more, the shape of the tailor cone 3 is stable regardless of the number of discharge electrodes 26, and the generation amount of the mist 4 is also stable.

[Number of discharge electrodes]
Subsequently, the relationship between the number of discharge electrodes 26 and the distance p between the adjacent discharge electrodes 26 will be described using FIGS. 5 and 6.

  FIG. 5 is a diagram showing the relationship between the distance between the discharge electrodes 26 of the electrostatic atomizer 1 according to the present embodiment and the voltage gradient due to the increase in the number of discharge electrodes. In FIG. 5, the horizontal axis indicates the distance p between the adjacent discharge electrodes 26. The vertical axis shows the slope of the increase in electrostatic atomization voltage when the number of discharge electrodes 26 increases. In addition, electrostatic atomization voltage is an applied voltage required to perform electrostatic atomization, and is also called spray voltage.

  The data shown in FIG. 5 indicates that the number of discharge electrodes 26 is predetermined for each of three cases where the distance p is 2.5 mm (= 5 R), 4.3 mm (= 8.6 R), and 5.0 mm (= 10 R). It was obtained by measuring the change in electrostatic atomization voltage when the number (for example, 1) was increased. The case where the outer diameter R is 0.5 mm, the inner diameter r is 0.3 mm, the height h is 3 mm, the distance L between the electrodes is 6 mm, and the electric conductivity of the liquid 2 is 0.49 mS / cm ing.

  At this time, it is understood that the gradient of the increase of the electrostatic atomization voltage is decreased by increasing the distance p. When linear approximation is performed based on the values of three points, the gradient is zero when the distance p is about 8 mm. That is, when the distance p is about 16 times the outer diameter R, even if the number of discharge electrodes 26 is increased, the electrostatic atomization voltage does not increase.

  FIG. 6 is a diagram showing the relationship between the number of discharge electrodes 26 of the electrostatic atomizer 1 according to the present embodiment, the dielectric breakdown voltage and the electrostatic atomization voltage. In FIG. 6, the horizontal axis represents the number of discharge electrodes 26, and the vertical axis represents voltage.

  In the example shown in FIG. 6, the dielectric breakdown voltage is 9 kV, for example. That is, when a voltage exceeding 9 kV is applied between the counter electrode 30 and the liquid 2, dielectric breakdown occurs between the electrodes, and the mist 4 is not generated.

  In the data shown in FIG. 6, the outer diameter R is 0.5 mm, the inner diameter r is 0.3 mm, the height h is 3 mm, the distance L between the electrodes is 6 mm, and the electric conductivity of the liquid 2 is 0. The case of 49 mS / cm is shown. As shown in FIG. 3, the discharge electrodes 26 were arranged so as to spread in a regular hexagonal shape from the center according to the number thereof.

  As shown in FIG. 6, when the distance p between the adjacent discharge electrodes 26 is ten times or more of the outer diameter R, the electrostatic atomization voltage increases as the number of discharge electrodes 26 increases. Specifically, the number of discharge electrodes 26 and the electrostatic atomization voltage have a linear relationship. When the number of discharge electrodes 26 is 15 or more, the electrostatic atomization voltage exceeds 9 kV which is a dielectric breakdown voltage. For this reason, when the number of discharge electrodes 26 is 15 or more, the generation of the mist 4 becomes difficult.

  On the other hand, when the distance p between adjacent discharge electrodes 26 is at least 16 times the outer diameter R, the electrostatic atomization voltage is substantially constant at 5 kV regardless of the number of discharge electrodes 26. This is similar to the case described using FIG. 5 (ie, p = 8 mm (= 16 R) for R = 0.5 mm).

  Therefore, by making the distance p 16 times or more the outer diameter R, the number of discharge electrodes 26 can be infinitely increased, and the generation amount of the mist 4 as a whole of the electrostatic atomization device 1 can be made as necessary. It can be increased.

[Distance between counter electrode and discharge electrode]
Subsequently, the distance L between the counter electrode 30 and the discharge electrode 26 according to the present embodiment will be described with reference to FIG.

  The data shown in FIG. 7 indicates the case where the outer diameter R is 0.5 mm, the inner diameter r is 0.3 mm, the height h is 3 mm, and the electric conductivity of the liquid 2 is 0.49 mS / cm. ing. As shown in FIG. 3, the discharge electrodes 26 were arranged so as to spread in a regular hexagonal shape from the center according to the number thereof.

  FIG. 7 is a view showing the relationship between the inter-electrode distance L, the dielectric breakdown voltage and the electrostatic atomization voltage of the electrostatic atomizer 1 according to the present embodiment. In FIG. 7, the horizontal axis indicates the inter-electrode distance L, and the vertical axis indicates the voltage.

  As shown in FIG. 7, both the dielectric breakdown voltage and the electrostatic atomization voltage increase as the inter-electrode distance L increases. Specifically, the inter-electrode distance L and each of the dielectric breakdown voltage and the electrostatic atomization voltage have a linear relationship.

  When the inter-electrode distance L is shorter than about 3 mm, the breakdown voltage is lower than the electrostatic atomization voltage. Therefore, when the voltage application unit 40 applies an electrostatic atomization voltage, dielectric breakdown occurs between the counter electrode 30 and the discharge electrode 26. Therefore, in this case, the generation of the mist 4 is difficult.

  On the other hand, when the inter-electrode distance L is 3 mm or more, the dielectric breakdown voltage exceeds the electrostatic atomization voltage. For this reason, even if the voltage application unit 40 applies an electrostatic atomization voltage, the mist 4 can be generated without causing insulation breakdown between the counter electrode 30 and the discharge electrode 26.

  Further, in the present embodiment, the maximum value of the voltage that can be applied by the voltage application unit 40 is 10 kV from the viewpoint of safety and reduction of power consumption. As shown in FIG. 7, when the inter-electrode distance L is greater than about 25 mm, the electrostatic atomization voltage exceeds 10 kV.

  For this reason, in the present embodiment, the inter-electrode distance L is in the range of 3 mm to 25 mm. When the range is represented by the angle θ, as described above, the angle θ is 3 ° or more and 37 ° or less.

  The inter-electrode distance L may be 6 mm or more and 22 mm or less. When the inter-electrode distance L is 6 mm or more, the difference between the dielectric breakdown voltage and the electrostatic atomizing voltage can be increased, and the occurrence of dielectric breakdown due to the fluctuation of the applied voltage can be suppressed. In addition, when the inter-electrode distance L is 22 mm or less, the difference between the upper limit value of the applicable voltage and the electrostatic atomization voltage can be increased, and the mist 4 can be stably generated. The angle θ at this time is 3 ° or more and 21 ° or less.

  The inter-electrode distance L may be 8 mm or more and 20 mm or less. Thereby, the generation of the mist 4 can be further stabilized. The angle θ at this time is 3 ° or more and 16 ° or less.

[Effect, etc.]
As described above, the electrostatic atomizer 1 according to the present embodiment includes the liquid tank 10 for containing the liquid 2, and the ejection plate 20 having the plurality of openings 27 for ejecting the liquid 2, and And a voltage application section 40 for applying a predetermined voltage between the liquid 2 and the counter electrode 30. The ejection plate 20 has an electrode support plate 21 which is an example of a flat plate portion, and a plurality of discharge electrodes 26 which are an example of a plurality of cylindrical portions supported by the electrode support plate 21. Each of the plurality of discharge electrodes 26 protrudes from the electrode support plate 21 toward the counter electrode 30 and has an opening 27 at its tip. The distance p between two adjacent discharge electrodes 26 among the plurality of discharge electrodes 26 is at least 10 times the outer diameter R of each of the two discharge electrodes 26.

  Thereby, since the distance p between two adjacent discharge electrodes 26 is ten times or more of the outer diameter R, interference between two adjacent discharge electrodes 26 is suppressed. For this reason, the electric field is easily concentrated at the tip of the discharge electrode 26, and the shape of the tailor cone 3 formed at the tip is stabilized. The stabilization of the shape of the tailor cone 3 stabilizes the refinement (i.e., atomization) of the liquid 2 at the tip of the tailor cone 3, and the mist 4 is stably generated. Since the mist 4 is stably generated from each of the plurality of discharge electrodes 26, the electrostatic atomizer 1 according to the present embodiment stably sprays the liquid 2 in a sufficient amount as the mist 4 be able to.

  Also, for example, the ratio of the height h to the outer diameter R of the plurality of discharge electrodes 26 is 4 or more.

  Thereby, the shape of the tailor cone 3 formed at the tip of each of the plurality of discharge electrodes 26 can be made more stable. Therefore, according to the electrostatic atomizer 1 which concerns on this Embodiment, the liquid 2 of sufficient quantity can be sprayed as the mist 4 more stably.

  Also, for example, the counter electrode 30 has a plurality of through holes 31 corresponding to the plurality of discharge electrodes 26 one by one. The angle θ between the line K connecting the open end of each of the plurality of through holes 31 and the tip of the corresponding discharge electrode 26 and the central axis J of the corresponding discharge electrode 26 is 3 ° or more and 37 ° or less.

  Thus, it is possible to suppress the mist 4 from being caught by the counter electrode 30 while preventing the counter electrode 30 and the tip of the discharge electrode 26 from being separated too much. Therefore, according to the electrostatic atomizer 1 which concerns on this Embodiment, the liquid 2 of more quantity can be stably sprayed as the mist 4. As shown in FIG.

  Further, for example, when the electrode support plate 21 is viewed in plan, the plurality of discharge electrodes 26 are respectively disposed at predetermined positions and at the apexes of one or more regular hexagons concentric with the positions. .

  As a result, it is possible to arrange more discharge electrodes 26 in the area of a limited area while securing the distance between the plurality of discharge electrodes 26. That is, the plurality of discharge electrodes 26 can be densely arranged while suppressing the mutual interference of the plurality of discharge electrodes 26. Therefore, according to the electrostatic atomization apparatus 1 which concerns on this Embodiment, not only it can spray stably the liquid 2 of sufficient quantity as the mist 4, and size reduction can be implement | achieved.

(Modification)
Then, the modification of an embodiment is explained.

  In the above embodiment, the inter-electrode distance L between the counter electrode and the plurality of discharge electrodes is shown to be equal to each other, but the inter-electrode distance L may be different in each of the two discharge electrodes. The electrostatic atomizer according to the present modification includes a plurality of discharge electrodes having different heights. In the following, differences from the embodiment will be mainly described. The points that are not particularly described are the same as in the embodiment.

  FIG. 8 is a cross-sectional view showing the positional relationship between the plurality of discharge electrodes 126a to 126c and the counter electrode 30 of the electrostatic atomization device 101 according to the present modification. Similar to FIG. 2, FIG. 8 shows a cross section passing through the central axis of each of the plurality of discharge electrodes 126 a to 126 c.

  As shown in FIG. 8, in comparison with the electrostatic atomizing device 1 according to the embodiment, the electrostatic atomizing device 101 includes a plurality of discharge electrodes 126 a to 126 c instead of the plurality of discharge electrodes 26. The plurality of discharge electrodes 126a to 126c are the same as the discharge electrode 26 according to the embodiment except that the heights ha to hc from the main surface 22 of the electrode support plate 21 are different.

  The discharge electrode 126a is an example of a first cylindrical portion. The discharge electrode 126 a is a discharge electrode positioned at a position closest to the center among the plurality of discharge electrodes 126 a to 126 c when the electrode support plate 21 is viewed in plan. For example, the discharge electrode 126a corresponds to the discharge electrode 26a shown in FIG.

  The discharge electrodes 126 b and 126 c are an example of a plurality of second cylindrical portions disposed so as to surround the discharge electrode 126 a. The discharge electrodes 126 b and 126 c are located outside the discharge electrode 126 a when the electrode support plate 21 is viewed in plan. The discharge electrode 126c is located outside the discharge electrode 126b. For example, the discharge electrode 126b corresponds to the discharge electrode 26b shown in FIG. Also, for example, the discharge electrode 126c corresponds to the discharge electrode 26c shown in FIG. The discharge electrode 126c is the discharge electrode positioned at the outermost side among the plurality of discharge electrodes 126a to 126c.

  As shown in FIG. 8, the height ha of the discharge electrode 126a is higher than the heights hb and hc of the discharge electrodes 126b and 126c. Specifically, ha> hb> hc is satisfied. For example, the difference between ha and hb and the difference between hb and hc are each 0.3 mm or more and 1.0 mm or less. When the outer diameter of each of the discharge electrodes 126a to 126c is R, the difference between ha and hb and the difference between hb and hc are each 0.6 to 2 times the outer diameter R. Note that ha> hb = hc.

  In the present modification, since counter electrode 30 is formed in a flat plate shape, the distance La between counter electrode 30 and discharge electrode 126a is the distance between counter electrode 30 and each of discharge electrodes 126b and 126c. Less than Lb and Lc. Specifically, La <Lb <Lc is satisfied. The difference between La and Lb and the difference between Lb and Lc are equal to the difference between ha and hb and the difference between hb and hc, respectively. In addition, La <Lb = Lc may be sufficient.

  At this time, the heights ha and hb of the discharge electrodes 126a and 126b may be equal to each other, and only the height hc of the discharge electrode 126c may be smaller than the heights ha and hb. That is, it may satisfy ha = hb> hc. In this case, the discharge electrodes 126a and 126b correspond to one or more first cylindrical portions, and the discharge electrode 126c corresponds to a second cylindrical portion.

  As described above, in the electrostatic atomizer 101 according to the present modification, for example, the distances between the counter electrode 30 and each of the discharge electrodes 126a to 126c are different from each other.

  Thereby, since the variation in the electric field between the plurality of discharge electrodes 126a to 126c can be suppressed, the amount of mist 4 from each of the plurality of discharge electrodes 126a to 126c can be made substantially uniform.

  For example, when the plurality of discharge electrodes 126a to 126c are densely arranged, the electric field tends to be concentrated at the tip of the discharge electrode 126c arranged on the outer periphery.

  For this reason, for example, the plurality of discharge electrodes are a discharge electrode 126a which is an example of a first cylindrical portion, and discharge electrodes 126b and 126c which are an example of a plurality of second cylindrical portions arranged to surround the discharge electrode 126a. And contains. The distance La between the counter electrode 30 and the discharge electrode 126a is smaller than the distances Lb and Lc between the counter electrode 30 and each of the plurality of discharge electrodes 126b and 126c.

  Thereby, the electric field concentration of the discharge electrode 126c arrange | positioned on outer periphery can be relieve | moderated, and the quantity of the mist 4 from each of several discharge electrode 126a-126c can be made substantially equal.

  In the present modification, the height h of the discharge electrode is made different depending on the arrangement position in plan view, but the present invention is not limited to this. The height h of the discharge electrode may be constant regardless of the arrangement position in plan view, and the shape of the counter electrode may be different. For example, the counter electrode may be formed in a conical side shape so as to be farther from the discharge electrode as the position in the plan view is farther from the center. Alternatively, the counter electrode may be formed in a step-like shape so as to be farther from the discharge electrode as the position in the plan view is farther from the center.

  Moreover, in the present modification, the distance to the counter electrode may be closer to the outer discharge electrode. Thus, a higher electric field can be applied to the tip of the outer discharge electrode where the electric field tends to be concentrated. For this reason, the generation amount of the mist from the outer discharge electrode can be increased, and the spray amount of the mist as a whole can be increased.

(Others)
As mentioned above, although the electrostatic atomizer concerning this invention was demonstrated based on said embodiment and its modification, this invention is not limited to said embodiment.

  For example, in the above embodiment, the electrode support plate 21 is provided to cover the upper surface of the liquid 2 and the plurality of discharge electrodes 26 project upward, but the present invention is not limited thereto. For example, the electrode support plate 21 may cover the lower surface or the side surface of the liquid 2, and the plurality of discharge electrodes 26 may protrude downward, sideward, or diagonally. The spraying direction of the mist 4 by the electrostatic atomizer 1 is not limited to the upper side, but may be the lower side, the side direction, or an oblique direction.

  Also, for example, the ejection plate 20 may include a cylindrical nozzle formed of an insulating material instead of the conductive discharge electrode 26. For example, by supplying the ground potential to the liquid 2, the tail cone 3 can be formed at the tip of the nozzle even if the nozzle does not have conductivity, and the mist 4 can be stably sprayed.

  Further, for example, in the ejection plate 20, the electrode support plate 21 and the plurality of discharge electrodes 26 may be integrally formed. The jet plate 20 may be integrally formed, for example, by injection molding using a metal material or a resin material.

  Also, for example, the plurality of discharge electrodes 26 may include two discharge electrodes 26 whose distance p is smaller than 10 times the outer diameter R. Also, for example, the height h of each of the plurality of discharge electrodes 26 may be smaller than four times the outer diameter R.

  Further, for example, the shape of the arrangement of the plurality of discharge electrodes 26 is not limited to a regular hexagon, but may be a regular polygon. For example, the plurality of discharge electrodes 26 may be arranged at vertexes of a square such as p, 2p, or 3p, and at equal division points. Also, for example, the plurality of discharge electrodes 26 may be disposed at each intersection of the grid.

  Further, in the above embodiment, all or part of the components such as the controller 60 may be configured by dedicated hardware, or realized by executing a software program suitable for each component. It is also good. Each component may be realized by a program execution unit such as a central processing unit (CPU) or processor reading and executing a software program recorded on a recording medium such as a hard disk drive (HDD) or a semiconductor memory. Good.

  Also, components such as the controller 60 may be configured with one or more electronic circuits. Each of the one or more electronic circuits may be a general-purpose circuit or a dedicated circuit.

  The one or more electronic circuits may include, for example, a semiconductor device, an integrated circuit (IC), or a large scale integration (LSI). The IC or LSI may be integrated on one chip or may be integrated on a plurality of chips. Although the term “IC” or “LSI” is used here, the term changes depending on the degree of integration, and may be called system LSI, very large scale integration (VLSI), or ultra large scale integration (ULSI). In addition, an FPGA (Field Programmable Gate Array) programmed after LSI fabrication can be used for the same purpose.

  Also, the general or specific aspects of the present invention may be realized as a system, an apparatus, a method, an integrated circuit or a computer program. Alternatively, it may be realized by a computer readable non-transitory recording medium such as an optical disk, HDD or semiconductor memory in which the computer program is stored. Also, the present invention may be realized as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium.

  In addition, the present invention can be realized by arbitrarily combining components and functions in each embodiment without departing from the scope of the present invention or embodiments obtained by applying various modifications that those skilled in the art may think to each embodiment. The form is also included in the present invention.

DESCRIPTION OF SYMBOLS 1, 101 Electrostatic atomizer 2 Liquid 10 Liquid tank 20 Ejecting plate 21 Electrode support plate (flat-plate part)
26 Discharge electrode (tubular part)
26a, 126a Discharge electrode (first cylindrical portion)
26b, 26c, 26d, 126b, 126c Discharge electrode (second cylindrical portion)
27 opening 30 counter electrode 31 through hole 40 voltage applying portion

Claims (6)

A liquid tank for containing the liquid,
An ejection plate having a plurality of openings for ejecting the liquid;
A counter electrode disposed opposite to the plurality of openings;
A voltage application unit that applies a predetermined voltage between the liquid and the counter electrode;
The spout plate is
Flat part,
And a plurality of cylindrical portions supported by the flat plate portion;
Each of the plurality of cylindrical portions protrudes from the flat plate portion toward the counter electrode, and has the opening at its tip,
The distance between two adjacent cylindrical parts among the plurality of cylindrical parts is 10 or more times the outer diameter of each of the two cylindrical parts. Electrostatic atomization device. The electrostatic atomization device according to claim 1, wherein a ratio of a height to an outer diameter of each of the plurality of cylindrical portions is 4 or more. The electrostatic atomizer according to claim 1 or 2, wherein distances between the counter electrode and each of the two cylindrical portions are different from each other. The plurality of cylindrical portions are
A first tubular portion,
And a plurality of second tubular portions arranged to surround the first tubular portion,
The electrostatic atomization device according to claim 3, wherein a distance between the counter electrode and the first cylindrical portion is smaller than a distance between the counter electrode and each of the plurality of second cylindrical portions. The counter electrode has a plurality of through holes corresponding to the plurality of cylindrical portions in a one-to-one relationship,
The angle formed by the line connecting the open end of each of the plurality of through holes and the tip of the corresponding cylindrical portion with the central axis of the corresponding cylindrical portion is 3 ° or more and 37 ° or less. The electrostatic atomizer according to any one of 4. The plurality of cylindrical portions are respectively disposed at predetermined positions and at the apexes of one or more regular hexagonal shapes centered on the positions when the flat plate portion is viewed in a plan view. The electrostatic atomizer according to any one of 5.