WO2014112447A1

WO2014112447A1 - Electrostatic atomizer and method for controlling electrostatic atomizer

Info

Publication number: WO2014112447A1
Application number: PCT/JP2014/050372
Authority: WO
Inventors: バンタンダウ; ティボーテレベシー
Original assignee: 住友化学株式会社
Priority date: 2013-01-15
Filing date: 2014-01-10
Publication date: 2014-07-24

Abstract

An electrostatic atomizer (100) is provided with a spray electrode (1), a reference electrode (2), a control circuit (24), and a high-voltage device (22). A voltage is applied between the spray electrode (1) and the reference electrode (2). The control circuit (24) controls the amount of current flowing through the reference electrode (2) so as to keep said amount of current within a prescribed range. The high-voltage device (22) applies a voltage between the spray electrode (1) and the reference electrode (2) on the basis of the controlled current amount.

Description

Electrostatic spray device and control method of electrostatic spray device

The present invention relates to an electrostatic spraying device having excellent spray stability and a method for controlling the electrostatic spraying device.

Conventionally, a spraying apparatus that ejects liquid in a container from a nozzle has been applied to a wide range of fields. As this type of spraying device, an electrostatic spraying device that atomizes and sprays a liquid by electrohydrodynamics (EHD) is known. This electrostatic spraying device forms an electric field in the vicinity of the tip of the nozzle, and uses the electric field to atomize and spray the liquid at the tip of the nozzle. Patent Document 1 is known as a document disclosing such an electrostatic spraying device.

International Patent Publication WO2004 / 088952A2 (published on October 21, 2004)

However, the technique of Patent Document 1 has room for improvement in the following points.

The electrostatic spraying device of Patent Document 1 includes a spray electrode and a reference electrode, and each of the spray electrode and the reference electrode is adjacent to a dielectric material. The spray electrode is a conduit for spraying liquid, and has a shape in which a tip portion is cut at a certain angle so as to provide a focus point of an electric field between the spray electrode and the reference electrode. Thereby, the spray electrode becomes sharper toward the tip. And the structure which positioned the front-end | tip part of the spray electrode in the position most distant from the reference | standard electrode is disclosed by FIG. 4 (a) of patent document 1. FIG.

In this regard, in FIG. 4A of Patent Document 1, the electric field between the spray electrode and the reference electrode is weakened because the tip of the spray electrode is separated from the reference electrode, that is, the number of electric field force lines is small. Become. As a result, the spray substance is sprayed in the direction of the reference electrode, that is, the direction of the apparatus itself (hereinafter, this phenomenon may be referred to as spray back), and the spray substance may adhere to the electrostatic spray apparatus. .

When a droplet adheres between the spray electrode and the reference electrode during operation of the electrostatic spraying device, the spray electrode and the reference electrode are electrically connected by the droplet, and the spray electrode and the reference electrode are connected by the droplet. Leakage current may occur between the reference electrode and the reference electrode. If leakage current occurs, the amount of liquid sprayed from the electrostatic spray device may become unstable.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an electrostatic spraying device having excellent spray stability and a control method for the electrostatic spraying device.

In order to solve the above problems, an electrostatic spraying device according to one embodiment of the present invention includes a first electrode that sprays a substance and has a pointed tip that defines a spraying direction of the substance, Based on the second electrode to which a voltage is applied between the first electrode, the current control means for controlling the current value in the second electrode to a predetermined range, and the current value controlled by the current control means, Voltage applying means for applying a voltage between the first electrode and the second electrode, wherein the tip of the first electrode is at a position off the axis of the first electrode, and When viewed from the axial center of the first electrode, the first electrode is located on the opposite side to the side on which the second electrode is located.

In order to solve the above-described problem, an electrostatic spraying device control method according to an aspect of the present invention includes: the electrostatic spraying device sprays a substance and defines a spray direction of the substance. A current control step for controlling a current value in the second electrode to a predetermined range, comprising: a first electrode having a shape-like tip portion; and a second electrode to which a voltage is applied between the first electrode and the second electrode. A voltage applying step of applying a voltage between the first electrode and the second electrode based on the current value controlled in the current control step, wherein the tip portion of the first electrode is The second electrode is located at a position deviated from the axis of the first electrode, and is located on the opposite side to the side where the second electrode is located as viewed from the axis of the first electrode.

In the electrostatic spraying device, an electric field is formed between the first electrode and the second electrode by applying a voltage between the first electrode and the second electrode. At this time, the first electrode is positively charged and the second electrode is negatively charged (or vice versa). As a result, the first electrode sprays a positively charged droplet. The second electrode is ionized negatively by ionizing air in the vicinity of the electrode. The negatively charged air moves away from the second electrode due to the electric field formed between the electrodes and the repulsive force between the negatively charged air particles. This movement generates a flow of air (hereinafter sometimes referred to as an ion flow), and the positively charged droplets are sprayed away from the electrostatic spraying device by the ion flow.

At this time, in the conventional electrostatic spraying device, when the position of the pointed tip of the first electrode that defines the spraying direction of the substance is changed with respect to the second electrode, for example, the tip of the first electrode When moving away from the second electrode, the electric field strength between the first electrode and the second electrode becomes weak. As a result, the spray substance is sprayed in the direction of the second electrode, that is, in the direction of the electrostatic spraying device to generate a spray back, and the spraying material may adhere to the electrostatic spraying device. In that case, when a droplet adheres between the first electrode and the second electrode during operation of the electrostatic spraying device, the first electrode and the second electrode are electrically connected by the droplet, and the liquid Leakage current may be generated between the first electrode and the second electrode due to the droplet. As a result, the amount of liquid sprayed from the electrostatic spraying device may become unstable due to the occurrence of leakage current.

On the other hand, in the electrostatic spraying device according to one aspect of the present invention, even when the position of the pointed tip that defines the spraying direction of the substance of the first electrode with respect to the second electrode is changed, The current value in the second electrode is controlled within a predetermined range by the current control means. Then, a voltage is applied between the first electrode and the second electrode based on the current value controlled by the current control means. That is, by controlling the current value in the second electrode within a predetermined range, the voltage value applied between the first electrode and the second electrode is stabilized, and as a result, the first electrode and the second electrode The electric field strength during is also stable.

Therefore, the electrostatic spraying device (control method) according to one embodiment of the present invention can suppress the spray back to the device itself and suppress the occurrence of leakage current between the first electrode and the second electrode. . Therefore, the electrostatic spray device according to one embodiment of the present invention can maintain spray stability regardless of the position of the tip of the first electrode with respect to the second electrode.

In addition, in the electrostatic spraying device according to one aspect of the present invention, the distal end portion of the first electrode is located at a position off the axis of the first electrode and from the axis of the first electrode. As viewed, the second electrode is located on the opposite side of the side where the second electrode is located.

Accordingly, the electrostatic spraying device according to one embodiment of the present invention can spray the substance in a direction away from the first electrode, and reduce spray back to a region between the first electrode and the second electrode. It becomes possible. Thus, the electrostatic spraying device according to one embodiment of the present invention can further increase the stability of spraying.

The electrostatic spraying device according to the present invention sprays a substance and a voltage is applied between the first electrode having a pointed tip that defines the spraying direction of the substance and the first electrode. A second electrode; current control means for controlling a current value in the second electrode to a predetermined range; and a current value controlled by the current control means between the first electrode and the second electrode. Voltage applying means for applying a voltage to the first electrode, the tip of the first electrode is at a position off the axis of the first electrode, and viewed from the axis of the first electrode, It is the structure located in the opposite side to the side in which the said 2nd electrode is located.

Further, in the method for controlling an electrostatic spraying device according to the present invention, the electrostatic spraying device sprays a substance and has a first electrode having a pointed tip that defines the spraying direction of the substance, A current control step for controlling the current value in the second electrode to a predetermined range, and a current value controlled in the current control step. A voltage applying step of applying a voltage between the first electrode and the second electrode, wherein the tip end portion of the first electrode deviates from the axis of the first electrode. And is located on the side opposite to the side where the second electrode is located when viewed from the axial center of the first electrode.

Therefore, the electrostatic spraying device and the control method for the electrostatic spraying device according to the present invention have an effect of providing an electrostatic spraying device having excellent spray stability.

It is a figure for demonstrating the principal part structure of the electrostatic spraying apparatus which concerns on embodiment of this invention. It is a figure for demonstrating the external appearance of the electrostatic spraying apparatus which concerns on embodiment of this invention. An example of the block diagram of the power supply device which concerns on embodiment of this invention is shown. It is a figure for demonstrating the 1st position of the front-end | tip part of the spray electrode with respect to a reference | standard electrode. It is a figure for demonstrating the 2nd position of the front-end | tip part of the spray electrode with respect to a reference | standard electrode. It is a figure for demonstrating the 3rd position of the front-end | tip part of the spray electrode with respect to a reference | standard electrode. It is a figure for demonstrating the 4th position of the front-end | tip part of the spray electrode with respect to a reference | standard electrode. FIG. 5 is a top view of first to fourth positions of a tip portion of a spray electrode with respect to a reference electrode. It is a perspective view which shows a mode that the front-end | tip part of a spray electrode is located in the position corresponding to the point b of FIG. It is a perspective view which shows a mode that the front-end | tip part of a spray electrode is located in the position corresponding to the point c of FIG. It is a perspective view which shows a mode that the front-end | tip part of a spray electrode is located in the position corresponding to the point d of FIG. Spray over time when the tip of the spray electrode is provided at the positions of point a (0 °), point b (90 °), point c (180 °), and point d (270 °) shown in FIG. It is a graph which shows transition of quantity. It is the schematic for demonstrating the spraying direction when the front-end | tip part of a spray electrode is located in the reference | standard electrode side. It is the schematic for demonstrating the spraying direction when the front-end | tip part of a spray electrode is located on the opposite side to a reference electrode. It is a figure which shows the spray direction of the liquid in case the front-end | tip part of the spray electrode 1 is located in the position corresponding to the point a of FIG. It is a figure which shows the spray direction of the liquid in case the front-end | tip part of a spray electrode is located in the position corresponding to the point b of FIG. It is a figure which shows the spray direction of the liquid in case the front-end | tip part of a spray electrode is located in the position corresponding to the point c of FIG. It is a figure which shows the spray direction of the liquid in case the front-end | tip part of a spray electrode is located in the position corresponding to the point d of FIG. The front view of the electrostatic spraying apparatus which concerns on this Embodiment stood with respect to the ground is shown. It is a figure for comparing and explaining the spray electrode concerning this embodiment, and the spray electrode concerning other embodiments. It is a figure for demonstrating the housing | casing surface of the electrostatic spraying apparatus which concerns on this Embodiment.

Hereinafter, the electrostatic spraying apparatus 100 and the like according to the present embodiment will be described with reference to the drawings. In the following description, the same parts and components are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

[Regarding Configuration of Main Parts of Electrostatic Spraying Device 100]
First, the principal part structure of the electrostatic spraying apparatus 100 is demonstrated with reference to FIG. FIG. 1 is a diagram for explaining a main configuration of the electrostatic spraying apparatus 100.

The electrostatic spraying device 100 is a device used for spraying aromatic oil, agricultural chemicals, pharmaceuticals, agricultural chemicals, insecticides, air cleaning agents, etc., and at least a spray electrode (first electrode) 1 and a reference An electrode (second electrode) 2, a power supply device 3, and a dielectric 10 are provided. The electrostatic spraying device 100 may be realized by a configuration in which the power supply device 3 is provided outside and connected to the power supply device 3.

The spray electrode 1 has a conductive conduit such as a metallic capillary (for example, 304 type stainless steel) and a tip 5 that is a tip. The spray electrode 1 is connected to the reference electrode 2 via the power supply device 3. A spray substance is sprayed from the tip 5. The spray electrode 1 has an inclined surface 9 that is inclined with respect to the axial center of the spray electrode 1, and the tip is narrower and sharper toward the tip. And the spray direction of a spray substance is prescribed | regulated by the pointed shape (details are mentioned later).

The reference electrode 2 is made of a conductive rod such as a metal pin (for example, a 304 type steel pin). The spray electrode 1 and the reference electrode 2 are spaced apart from each other at a predetermined interval and are arranged in parallel to each other. Further, the spray electrode 1 and the reference electrode 2 are arranged, for example, at an interval of 8 mm from each other.

The power supply device 3 applies a high voltage between the spray electrode 1 and the reference electrode 2. For example, the power supply device 3 applies a high voltage of 1-30 kV (eg, 3-7 kV) between the spray electrode 1 and the reference electrode 2. When a high voltage is applied, an electric field is formed between the electrodes, and an electric dipole is generated inside the dielectric 10. At this time, the spray electrode 1 is positively charged and the reference electrode 2 is negatively charged (or vice versa). Then, negative dipoles are generated on the surface of the dielectric 10 closest to the positive spray electrode 1, and positive dipoles are generated on the surface of the dielectric 10 closest to the negative reference electrode 2. Are emitted by the spray electrode 1 and the reference electrode 2. Here, as described above, the charge generated in the reference electrode 2 is a charge having a polarity opposite to the polarity of the spray substance. Thus, the charge of the spray material is balanced by the charge generated at the reference electrode 2. Therefore, the electrostatic spraying device 100 can achieve spray stability by current feedback control based on the principle of charge balance. Details thereof will be described later.

The dielectric 10 is made of a dielectric material such as nylon 6, nylon 11, nylon 12, nylon 66, or a polyacetyl-polytetrafluoroethylene mixture. The dielectric 10 supports the spray electrode 1 at the spray electrode mounting portion 6 and supports the reference electrode 2 at the reference electrode mounting portion 7.

Next, the external appearance of the electrostatic spraying device 100 will be described with reference to FIG. FIG. 2 is a view for explaining the external appearance of the electrostatic spraying device 100.

As shown in the figure, the electrostatic spraying device 100 has a rectangular shape (may have other shapes). A spray electrode 1 and a reference electrode 2 are disposed on one surface of the apparatus. As shown in the figure, the spray electrode 1 is located in the vicinity of the reference electrode 2. An annular opening 11 is formed so as to surround the spray electrode 1, and an annular opening 12 is formed so as to surround the reference electrode 2. A voltage is applied between the spray electrode 1 and the reference electrode 2, whereby an electric field is formed between the spray electrode 1 and the reference electrode 2. A positively charged droplet is sprayed from the spray electrode 1. The reference electrode 2 is negatively charged by ionizing air in the vicinity of the electrode. The negatively charged air moves away from the reference electrode 2 due to the electric field formed between the electrodes and the repulsive force between the negatively charged air particles. This movement generates a flow of air (hereinafter also referred to as an ion flow), and positively charged droplets are sprayed in a direction away from the electrostatic spraying device 100 by the ion flow.

[About power supply 3]
FIG. 3 shows an example of a configuration diagram of the power supply device 3. The power source device 3 includes a power source 21, a high voltage generator (voltage applying means) 22, a monitoring circuit 23 that monitors the output voltage in the currents of the spray electrode 1 and the reference electrode 2, and the current value of the reference electrode 1 as a predetermined value. A control circuit (current control means) 24 for controlling the high voltage generator 22 so that the output voltage of the high voltage generator 22 becomes a desired value in a state where the value (predetermined range) is controlled (current control step). Prepare. To accommodate a variety of applications, the control circuit 24 includes a microprocessor 241 that may be designed to further adjust the output voltage and spray time based on other feedback information 25. Good. The feedback information 25 includes environmental conditions (temperature, humidity, and / or atmospheric pressure), liquid amount, arbitrary settings by the user, and the like.

The power source 21 can be a well-known power source, and includes a main power source or one or more batteries. The power source 21 is preferably a low voltage power source or a direct current (DC) power source. For example, one battery is formed by combining one or more voltaic batteries. Suitable batteries include AA batteries and AA batteries. The number of batteries depends on the required voltage level and the power consumption of the power source.

The high voltage generator 22 includes an oscillator 221, a transformer 222, and a converter circuit 223. The oscillator 221 converts direct current into alternating current, and the transformer 222 is driven with alternating current. A converter circuit 223 is connected to the transformer 222. Usually, the converter circuit 223 includes a charge pump and a rectifier circuit. The converter circuit 223 generates a desired voltage and converts alternating current into direct current. A typical converter circuit is a Cockloft-Walton circuit.

The monitoring circuit 23 includes a current feedback circuit 231 and may include a voltage feedback circuit 232 depending on applications. The current feedback circuit 231 measures the current value of the reference electrode 2. Since the electrostatic spray device 100 is charge-balanced, the current at the tip of the spray electrode 1 can be accurately monitored by measuring and referring to the current value of the reference electrode 2. According to this method, there is no need to provide an expensive, complicated and confusing measuring means at the tip of the spray electrode 1, and it is not necessary to estimate the contribution of the discharge (corona) current to the measuring current. The current feedback circuit 231 may include any conventional current measuring device such as a current transformer.

In a preferred embodiment, the current in the reference electrode 2 is measured by measuring the voltage in a set resistor (feedback resistor) connected in series with the reference electrode 2. In some embodiments, the measured voltage in the set register is read using an analog to digital (A / D) converter. In general, an analog / digital converter is a part of a microprocessor. A suitable microprocessor with an analog-to-digital converter is a PIC16F18 ** family of microprocessors from Microchip. The digital information is processed by the microprocessor to provide output to the control circuit 24.

In a preferred embodiment, the voltage measured by the set register is compared with a predetermined constant reference voltage value using a comparator. The comparator requires very low current (generally nanoamperes or less) and has a fast response speed. In many cases, the microprocessor 241 incorporates a comparator for that purpose. For example, the above-mentioned PIC16F1824 of the microchip family provides a suitable comparator having a very low input current value and a constant reference voltage. The reference voltage value input to the comparator is set using a D / A converter included in the microprocessor 241 and a selectable reference voltage value is prepared. In normal operation, the circuit can detect whether the measured current is higher or lower than the required value determined by the magnitude of the reference voltage and the feedback resistor and provides that information to the control circuit 24.

In applications where an accurate voltage value is required, the monitoring circuit 23 is also provided with a voltage feedback circuit 232 and measures the voltage applied to the spray electrode 1. In general, the applied voltage is monitored directly by measuring the voltage at the junction of the two resistors forming a voltage divider connecting the two electrodes. Alternatively, the applied voltage is monitored by measuring the voltage generated at a node in the Cockloft-Walton circuit using similar voltage divider principles. Similarly, for current feedback, the feedback information is processed through an A / D exchanger or by comparing the feedback signal with a reference voltage value using a comparator.

The control circuit 24 acquires information indicating the current value of the reference electrode 2 from the monitoring circuit 23, and compares the current value of the reference electrode 2 with a predetermined current value (for example, 0.867 μA). Then, if the current value of the reference electrode 2 is not a predetermined current value, the control circuit 24 controls the current value of the reference electrode 2 so as to be a predetermined current value. The control circuit 24 controls the current value of the reference electrode 2 to a predetermined current value, and then sets the amplitude, frequency, or duty cycle of the oscillator 221 and the voltage on / off time (or a combination thereof). By controlling, the output voltage of the high voltage generator 22 is controlled. In consideration of a manufacturing error for each unit of the power supply device 3 or a measurement error of the current value, the control circuit 24 sets the current value of the reference electrode 2 to a certain width instead of the “predetermined current value”. Control may be performed so as to be within a predetermined range (± 5%).

Other input (feedback information 25) may be input to the microprocessor 241 because it is necessary to compensate the voltage or duty cycle / spray interval based on the atmospheric temperature, humidity, atmospheric pressure, liquid amount of the sprayed substance, and the like. The information is given as analog information or digital information and is processed by the microprocessor 241. Based on the input information, the microprocessor 241 can perform compensation to increase the quality and stability of the spray by changing either the spray interval, the time to turn on the spray, or the applied voltage.

As an example, the power supply device 3 includes a temperature detection element such as a thermistor used for temperature compensation. In a certain embodiment, the power supply device 3 changes a spray space | interval according to the change of the temperature detected by the temperature detection element. The spray interval is the total power on / off time. For example, the power supply turns on the spray for 35 seconds (while the power supply applies a high voltage between the first electrode and the second electrode), and turns off for 145 seconds (while the power supply turns on the first electrode and the second electrode) In the case of a periodic spray interval (with no high voltage applied between them), the spray interval is 35 + 145 = 180 seconds. The spray interval can be changed by software built into the microprocessor 241 of the power supply and increases from the set point when the temperature rises and decreases from the set point when the temperature falls. The increase and decrease of the spray interval is preferably according to a predetermined index determined by the characteristics of the substance to be sprayed. For convenience, the compensation change amount of the spray interval may be limited so that the spray interval changes only between 0-60 ° C. (eg, 10-45 ° C.). For this reason, extreme temperatures recorded by the temperature sensing element are considered erroneous and are not considered, and for high and low temperatures, an acceptable but not optimal spray interval is set. Alternatively, the on / off interval of the spray interval may be adjusted to make the spray interval constant, and the spray time may be increased or decreased within the spray interval when the temperature rises or falls.

The power supply device 3 may further include an inspection circuit that detects the characteristics of the substance to be sprayed and generates characteristic information indicating the characteristics of the substance. The characteristic information generated by the inspection circuit is supplied to the control circuit 24. The control circuit 24 uses this characteristic information to compensate at least one voltage control signal. The voltage control signal is a signal generated based on the detection result of ambient environmental conditions (for example, temperature, humidity and / or atmospheric pressure, and / or spray amount), and adjusts the output voltage or spray time. It is a signal for. The power supply device 3 may include a pressure sensor in order to monitor the ambient pressure (atmospheric pressure).

The internal configuration of the power supply device 3 has been described above. However, the above description is an example of the power supply device 3, and the power supply device 3 may be realized by other configurations as long as it has the above function.

[Disposition of spray electrode 1]
In the electrostatic spraying apparatus 100, the arrangement of the spray electrode 1 with respect to the reference electrode 2 can be changed as appropriate. This will be described with reference to FIGS.

FIG. 4 is a view for explaining the first position of the tip portion 5 of the spray electrode 1 with respect to the reference electrode 2. FIG. 5 is a view for explaining the second position of the tip portion 5 of the spray electrode 1 with respect to the reference electrode 2. FIG. 6 is a view for explaining the third position of the tip portion 5 of the spray electrode 1 with respect to the reference electrode 2. FIG. 7 is a view for explaining the fourth position of the tip portion 5 of the spray electrode 1 with respect to the reference electrode 2. FIG. 8 is a top view of the first to fourth positions of the tip portion 5 of the spray electrode 1 with respect to the reference electrode 2.

In FIG. 4, the tip 5 of the spray electrode 1 is located closest to the reference electrode 2 as compared to the position of the tip 5 shown in FIGS. 5 to 7 (position indicated by a point a in FIG. 8). . In FIG. 8, the point a is represented as 0 °. This defines the position of the point a as 0 ° with the axis P of the spray electrode 1 as a reference.

In FIG. 5, the tip portion 5 of the spray electrode 1 is located in the middle of the position of the tip portion 5 shown in FIGS. 4 and 6 (the position indicated by the point b in FIG. 8). This indicates that the position rotated by 90 ° from the point a with respect to the axis P of the spray electrode 1 is the point b.

In FIG. 6, the tip 5 of the spray electrode 1 is located farthest from the reference electrode 2 compared to the position of the tip 5 shown in FIGS. 4, 5, and 7 (indicated by a point c in FIG. 8). Position). In FIG. 8, the point c is represented as 180 °. This indicates that the position rotated by 180 ° from the point a with respect to the axis P of the spray electrode 1 is the point c.

7, the tip 5 of the spray electrode 1 is located in the middle of the position of the tip 5 shown in FIGS. 4 and 6 (the position indicated by the point d in FIG. 8). This indicates that the position rotated by 270 ° from the point a with respect to the axis P of the spray electrode 1 is the point d.

Here, FIGS. 9 to 11 are perspective views showing how the position of the tip 5 of the spray electrode 1 with respect to the reference electrode 2 is changed. Among these, FIG. 9 is a perspective view showing a state in which the tip portion 5 of the spray electrode 1 is located at a position corresponding to the point b in FIG. FIG. 10 is a perspective view showing a state where the tip portion 5 of the spray electrode 1 is located at a position corresponding to the point c in FIG. FIG. 11 is a perspective view showing a state where the tip portion 5 of the spray electrode 1 is located at a position corresponding to the point d in FIG. 9 to 11, the reference electrode 2 is not shown, but is located on the right side of the drawing.

Here, the arrangement of the spray electrode 1 can also be expressed as follows. That is, at the position indicated by the point c in FIG. 8, the tip portion 5 of the spray electrode 1 is located on the opposite side to the side where the reference electrode 2 is located when viewed from the axial center of the spray electrode 1. Further, at the positions indicated by points a, b, and d in FIG. 8 (or the positions excluding the point c when making a round with the points a to b to c to d to a), the tip 5 of the spray electrode 1 is In addition, the spray electrode 1 and the reference electrode 2 are deviated from the line connecting the respective axis centers.

[Effect of changing the arrangement of the spray electrode 1]
As described above, in the electrostatic spraying device 100, the arrangement of the tip portion 5 of the spray electrode 1 relative to the reference electrode 2 can be changed as appropriate.

Here, it is of course possible to change the position of the tip 5 of the spray electrode 1 with respect to the reference electrode 2 also in the conventional electrostatic spraying apparatus. However, in that case, the electric field strength of the electric field formed between the spray electrode and the reference electrode is weakened by the tip of the spray electrode being moved away from the reference electrode. As a result, the spray substance is sprayed in the direction of the reference electrode, that is, the direction of the electrostatic spraying device, and spray back occurs, and the spraying material may adhere to the electrostatic spraying device.

When a droplet adheres between the spray electrode and the reference electrode during operation of the electrostatic spraying device, the spray electrode and the reference electrode are electrically connected by the droplet, and the spray electrode and the reference electrode are connected by the droplet. Leakage current may occur between the reference electrode and the reference electrode. As a result, the amount of liquid sprayed from the electrostatic spraying device may become unstable due to the occurrence of leakage current.

Further, in the conventional electrostatic spraying device, when the tip of the spray electrode is brought close to the reference electrode side, the electric field strength of the electric field formed between the spray electrode and the reference electrode is increased, resulting in the spraying. The state changes, and stable spraying cannot be realized.

On the other hand, in the electrostatic spraying device 100 according to the present embodiment, even if the tip portion 5 of the spray electrode 1 is changed to a position away from the reference electrode 2, the current control is performed by the power supply device 3 and the reference is performed. The current value of the electrode 2 is kept constant. Thereby, the voltage applied between the spray electrode 1 and the reference electrode 2 is increased (voltage application step), and the electric field strength between the spray electrode 1 and the reference electrode 2 can be maintained. As a result, the spray back to the electrostatic spraying apparatus 100 is suppressed, and a situation in which a leakage current is generated between the spray electrode 1 and the reference electrode 2 can be avoided.

Similarly, in the electrostatic spraying device 100, even if the tip 5 of the spray electrode 1 is changed to a position approaching the reference electrode 2, the current value of the reference electrode 2 is kept constant by receiving current control from the power supply device 3. Kept. Thereby, the voltage applied between the spray electrode 1 and the reference electrode 2 becomes weak, and the electric field strength between the spray electrode 1 and the reference electrode 2 can be maintained. As a result, the electrostatic spraying device 100 can maintain spray stability.

As described above, the electrostatic spraying device 100 can maintain spray stability regardless of the position of the tip portion 5 of the spray electrode 1 with respect to the reference electrode 2.

[About spray stability by electrostatic spraying apparatus 100]
Therefore, the spray stability by the electrostatic spray apparatus 100 will be described with reference to FIG. FIG. 12 shows the case where the tip 5 of the spray electrode 1 is provided at the positions of point a (0 °), point b (90 °), point c (180 °), and point d (270 °) shown in FIG. It is a graph which shows transition of the spraying quantity with time progress of. In this graph, the horizontal axis indicates the elapsed time (days), and the vertical axis indicates the spray amount (g / day). Further, two samples when the tip 5 of the spray electrode 1 is provided at the positions of point b (90 °), point c (180 °), and point d (270 °) shown in FIG. One sample when provided at (0 °) was subjected to a spraying experiment. The result of the spray experiment is shown in FIG.

According to this graph, it can be seen that when the tip 5 of the spray electrode 1 is provided at the points a to d, the spray amount increases with the passage of time and the spray stability is maintained at any position.

As described above, even if the relative position between the tip 5 of the spray electrode 1 and the reference electrode 2 is changed, the current value of the reference electrode 2 is kept constant by receiving the current control by the power supply device 3. By being. That is, since the current value of the reference electrode 2 is kept constant, the voltage applied between the spray electrode 1 and the reference electrode 2 is controlled, and the electric field strength between the spray electrode 1 and the reference electrode 2 is maintained. By being done.

As described above, the electrostatic spraying device 100 can appropriately change the arrangement of the tip portion 5 of the spray electrode 1 with respect to the reference electrode 2 and can maintain the spray stability. Compared with, the stability of spraying can be improved.

[Spray direction from spray electrode 1 and spray back]
Next, the spray direction from the spray electrode 1 and the spray back will be described with reference to FIG.

FIG. 13 is a schematic view for explaining the spray direction when the tip portion 5 of the spray electrode 1 is positioned on the reference electrode 2 side. FIG. 14 is a schematic diagram for explaining the spray direction when the tip 5 of the spray electrode 1 is located on the side opposite to the reference electrode 2.

As shown in FIGS. 13 and 14, the spray electrode 1 has an inclined surface 9 that is inclined with respect to the axial center of the spray electrode 1, and becomes thinner toward the tip. In FIG. 13, the inclination is formed in the upper left direction of the drawing (direction approaching the reference electrode 2). At this time, the liquid is sprayed from the spray electrode 1 along the slope, that is, in the direction of the reference electrode 2. In FIG. 14, the inclination is formed in the upper right direction of the drawing (a direction far from the reference electrode 2). At this time, the liquid is sprayed from the spray electrode 1 along the slope, that is, in the direction opposite to the reference electrode 2. Thus, the direction in which the liquid is sprayed is defined by the shape of the tip portion 5 of the spray electrode 1 (more specifically, the tilt direction of the tilted surface 9).

This is because a focal point of the electric field is formed at the top of the tip 5 of the spray electrode 1 where there is a change in shape and liquid movement is likely to occur, and the focus of the electric field is on the inclined surface of the tip 5. In contrast, it is formed in a direction perpendicular to a plane perpendicular to the surface.

Next, how the liquid is sprayed will be described with reference to FIGS. Although not shown in the drawings, the reference electrode 2 is located on the right side of each drawing.

FIG. 15 is a diagram showing the spray direction of the liquid when the tip 5 of the spray electrode 1 is located at a position corresponding to the point a in FIG. It can be seen that the electric field reflected in white in the figure is in the direction of the reference electrode 2.

FIG. 16 is a diagram showing the spraying direction of the liquid when the tip 5 of the spray electrode 1 is located at a position corresponding to the point b in FIG. It can be seen that the focus of the electric field reflected in white in the figure is directed downward (direction perpendicular to the line segment connecting the spray electrode 1 and the reference electrode 2).

FIG. 17 is a diagram showing the spray direction of the liquid when the tip 5 of the spray electrode 1 is located at a position corresponding to the point c in FIG. It can be seen that the electric field reflected in white in the figure is in the opposite direction to the reference electrode 2.

FIG. 18 is a diagram showing a liquid spraying direction when the tip 5 of the spray electrode 1 is located at a position corresponding to the point d in FIG. It can be seen that the focus of the electric field reflected in white in the figure is directed upward (direction perpendicular to the line segment connecting the spray electrode 1 and the reference electrode 2).

Thus, also from FIG. 15 and the like, it was confirmed that the direction in which the liquid is sprayed is defined by the shape of the tip portion 5 of the spray electrode 1, specifically, the inclination direction of the inclined surface 9.

Here, the spraying direction of the liquid has been described with reference to FIG. 15 and the like. Next, positions where spray back can occur will be described with reference to FIG. FIG. 19 shows a front view of the electrostatic spraying device 100 erected with respect to the ground. In the figure, the lower side is the direction of gravity.

The electrostatic spraying device 100 has a spray electrode 1 and a reference electrode 2 disposed on one surface thereof. As shown in the figure, the spray electrode 1 is located in the vicinity of the reference electrode 2. An annular opening 11 is formed so as to surround the spray electrode 1, and an annular opening 12 is formed so as to surround the reference electrode 2. A voltage is applied between the spray electrode 1 and the reference electrode 2, whereby an electric field is formed between the spray electrode 1 and the reference electrode 2. A positively charged droplet is sprayed from the spray electrode 1. The reference electrode 2 is negatively charged by ionizing air in the vicinity of the electrode. The negatively charged air moves away from the reference electrode 2 due to the electric field formed between the electrodes and the repulsive force between the negatively charged air particles. This movement generates an ion flow, and droplets positively charged by the ion flow are sprayed away from the electrostatic spraying device 100.

Here, in the area La, area Lb, area Lc, and area Ld in the figure, the tip 5 of the spray electrode 1 is located at the positions indicated by the points a, b, c, and d in FIG. The position at which the spray substance is sprayed back is shown.

As described with reference to FIG. 13, when the tip 5 of the spray electrode 1 is at the position of point a in FIG. 8, the spray substance is sprayed from the spray electrode 1 toward the reference electrode 2. Therefore, if the lower side of the drawing is the lower side (the direction of gravity), the region La to be sprayed back is the lower side between the spray electrode 1 and the reference electrode 2.

As described above, the direction in which the liquid is sprayed is defined by the shape of the tip portion 5 of the spray electrode 1 (more specifically, the inclination direction of the inclined surface 9 (not shown)). Therefore, similarly to the region La, the region Lb, the region Lc, and the region L are determined by the inclination direction of the inclined surface 9 of the distal end portion 5 of the spray electrode 1. Therefore, the region Lb is located below the spray electrode 1, and the region Lc is located on the opposite side of the reference electrode 2 when viewed from the spray electrode 1. The region Ld is located above the spray electrode 1 (in the direction opposite to gravity).

Here, the electrostatic spraying device 100 is used for spraying aromatic oil, agricultural chemicals, pharmaceuticals, agricultural chemicals, insecticides, air cleaning chemicals, and the like. Therefore, the relative position between the tip 5 of the spray electrode 1 and the reference electrode 2 may be appropriately changed when there is a suitable direction for the spraying direction of the substance depending on the application. Thereby, a spray substance is sprayed in a more suitable direction, and the spray most suitable for the use of the electrostatic spraying apparatus 100 can be realized.

Moreover, at this time, even if the relative position between the tip portion 5 of the spray electrode 1 and the reference electrode 2 changes, the current value of the reference electrode 2 is kept constant by receiving the current control by the power supply device 3. Since the current value of the reference electrode 2 is kept constant, the voltage applied between the spray electrode 1 and the reference electrode 2 is controlled, and the electric field strength between the spray electrode 1 and the reference electrode 2 is maintained. Is done.

Thereby, the electrostatic spraying device 100 can appropriately change the arrangement of the tip portion 5 of the spray electrode 1 with respect to the reference electrode 2 and can maintain the spray stability. Thus, the electrostatic spraying device 100 can improve the stability of spraying compared with the conventional electrostatic spraying device.

In addition, when a droplet adheres between the spray electrode 1 and the reference electrode 2 during operation of the electrostatic spraying apparatus 100, the spray electrode 1 and the reference electrode 2 are electrically connected by the droplet, and the liquid A leakage current may be generated between the spray electrode 1 and the reference electrode 2 due to the droplets.

Therefore, it is preferable that spray back occurs in the direction of the region Lc from the viewpoint of suppressing the occurrence of leakage current. In addition, it was confirmed that the substance sprayed from the spray electrode 1 flies farthest from the reference electrode 2 when the tip 5 of the spray electrode 1 is positioned at the point c. For this reason, when the tip part 5 of the spray electrode 1 is located at the position of the point c, it can be said that wetting is most easily controlled on the surface of the apparatus.

However, even if the tip 5 of the spray electrode 1 is positioned between the point b and the point c and between the point c and the point d, for example, between the region Lb and the region Lc and between the region Lc and the region Ld. It is also possible to limit the area where spray back can occur. In addition, it can be said that the tip portion 5 of the spray electrode 1 may be positioned at the point a if there is no operational problem with the occurrence of spray back in the region La.

From this, the electrostatic spraying device 100 can position the tip of the spray electrode 1 that defines the spraying direction of the substance at any position in order to maintain the stability of spraying. Effects that cannot be achieved by the electrospraying device can be realized.

[Other Examples of Spray Electrode]
Next, a modified example of the spray electrode 1 will be described with reference to the drawings. FIG. 20 is a diagram for comparing and explaining the spray electrode 1 according to the present embodiment and the spray electrode 15 according to another embodiment.

Each of the spray electrode 1 and the spray electrode 15 has an inclined surface 9 that is inclined with respect to the axis of the spray electrode, and the tip becomes narrower and sharper toward the tip. And the spray direction of a spray substance is prescribed | regulated by the shape.

At this time, the spray electrode 1 is inclined with respect to the axial center of the spray electrode 1 and defines the shape of the tip portion of the spray electrode 1 when the sprayed electrode 1 is sprayed upward. The contact 16 between the lower end of 9 and the outer surface of the spray electrode 1 has an acute angle. Therefore, when a voltage is applied between the spray electrode 1 and the reference electrode 2, the electric field focal point is formed at the contact 16, and thus an electric field may be formed between the reference electrode 2 and the contact 16. is there. Thereby, it is necessary to consider the case where the substance is sprayed from the contact point 16 instead of the front end portion 5 and a suitable substance spray from the electrostatic spraying device 100 is obstructed.

In this regard, the spray electrode 15 is inclined with respect to the axial center of the spray electrode 15 and defines the shape of the distal end portion of the spray electrode 15 when the sprayed electrode 15 is sprayed on the material spray side. The contact 17 between the lower end of 9 and the outer surface of the spray electrode 15 has a curved surface (curved surface portion). Therefore, when a voltage is applied between the spray electrode 15 and the reference electrode 2, the electric field focal point is not formed at the contact point 17, and the electric field is generated between the reference electrode 2 and the tip 5 of the spray electrode 15. Is formed. Thereby, a substance is sprayed from the front-end | tip part 5, and the suitable substance spray from the electrostatic spraying apparatus 100 can be ensured.

When the electrostatic spraying device 100 uses the spray electrode 1, when the tip 5 is positioned at the point c in FIG. 8, a voltage is applied between the spray electrode 1 and the reference electrode 2 and the contact 16. It is considered that the focus of the electric field is easily formed. Therefore, it can be said that it is effective to use the spray electrode 15 when positioning the tip of the spray electrode at the point c in FIG.

[About the material collection groove]
Next, the groove 34 and the liquid recovery part (substance recovery part) 35 formed in the electrostatic spraying device 100 will be described with reference to FIG. FIG. 21 is a diagram for explaining the housing surface of the electrostatic spraying device 100. The lower side of the drawing is the direction of gravity. Moreover, in FIG. 21, the electrostatic spraying apparatus 100 is in a standing state.

The electrostatic spraying device 100 shown in FIG. An annular opening 11 formed so as to surround the spray electrode 1 and an annular opening 12 formed so as to surround the reference electrode 2 are formed on the surface 30 of the electrostatic spraying apparatus 100 on the liquid spray side. And are formed.

Furthermore, a groove 34a, a groove 34b, and a groove 34c are formed on the surface 30. The groove 34b and the groove 34c are formed to extend in the longitudinal direction (the vertical direction in the drawing) of the electrostatic spraying device 100, and are connected to each other via the groove 34a. The groove 34a is formed to extend in the short direction (left and right direction in the drawing) of the electrostatic spraying apparatus 100, and connects the groove 34b and the groove 34c via the groove 34a. In FIG. 21, the groove 34a, the groove 34b, and the groove 34c intersect in a substantially vertical direction. The groove 34b and the groove 34c are not essential, and only the groove 34a may be formed.

Furthermore, a liquid recovery part 35a, a liquid recovery part 35b, and a liquid recovery part 35c are formed in the groove 34a. The liquid recovery part 35a is located at the center of the groove 34a extending in the horizontal direction, and the liquid recovery part 35b and the liquid recovery part 35c are located at both ends of the groove 34a. Furthermore, each of the liquid recovery part 35a, the liquid recovery part 35b, and the liquid recovery part 35c is formed in a trapezoidal shape, for example, and the shorter one of the upper and lower bases is located on the lower side in the gravity direction ( Hereinafter, this shape may be referred to as an inverted trapezoid). In addition, the liquid recovery part 35a, the liquid recovery part 35b, and the liquid recovery part 35c may be formed in the groove 34a with an inclination, for example, so as to easily recover the liquid inside the electrostatic spraying device 100. .

Here, the groove 34a is formed with a length of 26 mm and a height of 1 mm, for example. The liquid recovery part 35a is formed with an upper base of 6 mm, a lower and lower part of 4 mm, and a height of 1.6 mm. The liquid recovery part 35b and the liquid recovery part 35c are formed with an upper base of 5 mm, a lower and lower part of 3 mm, and a height of 1.6 mm. However, these numerical values are examples, and are not limited to these numerical values.

Here, as shown in the drawing, the spray electrode 1 is connected to the electric conductor 38, and a voltage is applied from the power supply device 3 (not shown) through the electric conductor 38. The reference electrode 2 is connected to the electrical conductor 39, and a voltage is applied from the power supply device 3 (not shown) via the electrical conductor 39. At this time, the electric conductor 38 and / or the electric conductor 39 may be coated with a material having water / oil repellency. The spray electrode 1 and / or the reference electrode 2 may be attached with an O-ring made of chemically resistant silicon, fluorine rubber, resin, or the like.

The electrostatic spraying apparatus 100 has the above-described configuration, thereby providing the following effects.

Specifically, on the surface 30 of the electrostatic spraying apparatus 100, a liquid recovery part 35a, a liquid recovery part 35b, and a liquid recovery part 35c are formed in the groove 34a. For this reason, when the liquid flows into the groove 34a, the liquid can smoothly enter the liquid recovery part 35a, the liquid recovery part 35b, and the liquid recovery part 35c. Even when the electrostatic spraying device 100 is tilted left and right, since the liquid recovery part 35b and the liquid recovery part 35c are formed at both ends of the groove 34a, the liquid is recovered from the liquid recovery part 35b and the liquid recovery part. The part 35c can be entered.

As a result, even if the liquid that has entered the groove 34a has high viscosity and / or low volatility, the liquid can smoothly enter the liquid recovery unit 35a, the liquid recovery unit 35b, and the liquid recovery unit 35c. It can be recovered in the electrostatic spraying device 100.

Therefore, even if the position (region) where spray back is likely to occur is changed according to the position of the tip portion 5 of the spray electrode 1 with respect to the reference electrode 2, the liquid recovery portion 35 is formed in the groove 34 located in the vicinity of the position. By doing so, the sprayed liquid can be quickly recovered. In other words, in the electrostatic spraying device 100, the position of the tip portion 5 of the spray electrode 1 with respect to the reference electrode 2 can be changed as appropriate according to the position of the liquid recovery unit 35, thereby increasing the degree of freedom in device design. Is possible.

[3. Supplement)
The present invention can also be configured as follows.

In the electrostatic spraying device according to one aspect of the present invention, the tip of the first electrode may be positioned farthest from the second electrode when viewed from the axial center of the first electrode.

According to said structure, the electrostatic spraying apparatus which concerns on 1 aspect of this invention sprays a substance in the direction furthest away from the said 1st electrode, and sprays back to the area | region between a 1st electrode and a 2nd electrode. Can be reduced. Thereby, the electrostatic spraying apparatus which concerns on 1 aspect of this invention can improve the stability of spraying.

In the electrostatic spraying device according to one aspect of the present invention, the first electrode is inclined with respect to the axis of the first electrode when the side on which the substance is sprayed is the upper side in the first electrode. The lower end portion of the inclined surface may include a curved surface portion.

Since the focal point of the electric field is likely to be formed at the corner, the electrostatic spraying device according to one embodiment of the present invention has the above-described configuration, so that a voltage is applied between the first electrode and the second electrode. Sometimes, the focal point of the electric field is not formed on the curved surface portion, and an electric field is formed between the tip portion of the first electrode and the second electrode. Therefore, in the electrostatic spraying device according to one embodiment of the present invention, the stability of spraying can be improved by spraying a substance from the tip of the first electrode.

The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

The present invention can be used in an electrostatic spraying apparatus that sprays aromatic oil, chemicals for agricultural products, pharmaceuticals, agricultural chemicals, insecticides, air cleaning chemicals, and the like.

1,15 Spray electrode (first electrode)
2 Reference electrode (second electrode)
3 power supply device 5 tip 6 spray electrode mounting portion 7 reference electrode mounting portion 9 inclined surface 10 dielectric 11, 12

opening

16, 17 contact 21 power supply 22 high voltage generator (voltage applying means)
23 monitoring circuit 24 control circuit (current control means)
25 Feedback information 30 Surface 35

Liquid recovery unit

38, 39 Electrical conductor 100 Electrostatic spraying device 221 Oscillator 222 Transformer 223 Converter circuit 231 Current feedback circuit 232 Voltage feedback circuit 241 Microprocessor L, La to Ld Region P Axis center

Claims

A first electrode having a pointed tip that sprays a substance and defines a spray direction of the substance;
A second electrode to which a voltage is applied between the first electrode;
Current control means for controlling the current value in the second electrode to a predetermined range;
Voltage application means for applying a voltage between the first electrode and the second electrode based on the current value controlled by the current control means,
The tip of the first electrode is at a position deviated from the axis of the first electrode, and is opposite to the side where the second electrode is located as viewed from the axis of the first electrode. An electrostatic spraying device characterized by being positioned.
The electrostatic spraying device according to claim 1, wherein the tip of the first electrode is located farthest from the second electrode when viewed from the axial center of the first electrode.
When the side spraying the substance in the first electrode is the upper side,
The first electrode includes an inclined surface that is inclined with respect to the axis of the first electrode,
The electrostatic spraying device according to claim 1, wherein the lower end portion of the inclined surface has a curved surface portion.
A method for controlling an electrostatic spraying device, comprising:
The electrostatic spraying device sprays a substance, and a second electrode to which a voltage is applied between the first electrode having a pointed tip that defines the spraying direction of the substance and the first electrode And comprising
A current control step of controlling the current value in the second electrode to a predetermined range;
A voltage applying step of applying a voltage between the first electrode and the second electrode based on the current value controlled in the current control step,
The tip of the first electrode is at a position deviated from the axis of the first electrode, and is opposite to the side where the second electrode is located as viewed from the axis of the first electrode. A control method characterized by being positioned.