JP7807052B2 - Induction charging type electrostatic sprayer - Google Patents

Description

The present invention relates to an induction-type electrostatic sprayer that uses static electricity to spray liquids such as chemicals.

As a first example of background art, an induction-charging electrostatic sprayer is described in Patent Document 1. As shown in FIG. 17, this induction-charging electrostatic sprayer 110 includes a pair of electrostatic spray units 101, 101 that spray to the left and right, respectively. The electrostatic spray unit 101 includes a nozzle unit 111 that sprays droplets of liquid supplied through a nozzle unit 142; an electrode support shaft 102 whose base end is supported on the base end side of the nozzle unit 111 and whose tip end extends laterally from the nozzle unit 111 toward the tip end side of the nozzle unit 111 at a distance; a substantially annular electrode 105 disposed on the tip of the electrode support shaft 102; and a leakage prevention unit 104 disposed on the surface between the base end of the electrode support shaft 102 and the electrode 105. The electrostatic sprayer is configured to inductively charge the droplets by applying a high voltage between the liquid and the electrode 105.

The second background art is exemplified by the electrostatic spraying device described in Patent Document 2. As shown in Figure 18, the high-voltage supply circuit 202 in this electrostatic spraying device 201 supplies high voltage from a high-voltage generation unit 203 to each of the electrodes 204a of multiple electrostatic spraying units 204, which spray countless electrically charged droplets. If each electrostatic spraying unit 204 is equipped with a heater 205 that dries the droplets to prevent electrical leakage due to droplets adhering to the unit, it is also necessary to supply power from a heater control circuit 207 to each heater 205 via a heater power supply circuit 206.

An example of a third background art is the electrostatic spraying device for an agricultural vehicle described in Patent Document 3. As shown in Figure 19, this electrostatic spraying device is configured so that rod-shaped front and rear high-voltage conductors 361, 361 extending in the left-right direction are arranged below spray nozzles 303, etc., which are provided at approximately predetermined intervals on a spray boom 304 extending in the left-right direction, and high voltage is applied to the front and rear high-voltage conductors 361, 361. Only the front and rear high-voltage conductors 361, 361 located below the spray nozzles 303, etc. of the spray boom 304 are configured as annular portions 361a, etc. that move away from the spray nozzles 303, etc. in a plan view, and adjacent annular portions 361a, etc. on the left and right are connected by linear portions extending in the left-right direction.

JP 2013-163154 A Japanese Patent Application Laid-Open No. 2007-130581 JP 2010-104321 A

In the device relating to the first background art, each electrostatic spraying unit 101 is equipped with an electrode 105 supported via an electrode support shaft 102 having a leakage prevention unit 104. This means that the distance from the nozzle tube 142 that supplies the liquid to the tip of the nozzle unit 111 is long. If a single nozzle tube 142 is configured to spray on both sides, the distance from the center of the machine body to the tip of the nozzle unit 111 becomes large, which could result in uneven spraying due to the proximity of the crop to the nozzle unit 111. Therefore, in this device, two nozzle tubes 142 are installed alternately to shorten the distance from the center of the machine body to the tip of the nozzle unit 111 and prevent uneven spraying. However, the need for two nozzle tubes 142 creates problems, such as a complex configuration and increased costs.

Furthermore, in the device relating to the second background art, since each electrostatic spray unit 204 is provided with an electrode 204a, it is necessary to wire a high-voltage supply circuit 202 and, in some cases, a heater power supply circuit 206 to each electrode 204a. This creates the problem that the more nozzles there are, the more complicated the wiring becomes and the higher the cost becomes.

In contrast to this second background art, the electrostatic spraying device according to the third background art uses high-voltage conductors 361, 361 as a common electrode for multiple spray nozzles 303, etc., and furthermore, annular portions 361a, etc. are formed in the high-voltage conductors 361, 361 at locations close to the spray nozzles 303, etc., which move away from the spray nozzles 303, etc. in the front-to-back and left-to-right directions in a plan view. As a result, the number of spray nozzles 303 installed and the relative positions of the spray nozzles 303, etc. are fixed and cannot be adjusted, which poses a problem.

Furthermore, in both background arts, the electrode is formed in a circular shape so that its inner circumference is close to the outer circumference of the droplet diffusion range when the spray angle from the spray nozzle is at its maximum. Therefore, if the spray angle becomes smaller than the maximum by increasing or decreasing the spray amount, the smaller the angle becomes, the greater the distance between the droplets and the electrode, resulting in a problem of reduced charging efficiency of the droplets.

Furthermore, at the nozzle of an induction-charging electrostatic sprayer, negatively charged droplets are attracted to the positive electrode, causing the liquid consisting of these droplets to drip from the nozzle. If multiple spray nozzles 303 in the electrostatic sprayer according to the third background art were vertically aligned and the high-voltage conductors 361, 361 serving as a common electrode were extended vertically, the droplets from all the spray nozzles 303 would be attracted to the common high-voltage conductor 361, causing the liquid to drip downward. At the lowest point, the liquid would drip continuously downward, creating the impression of a liquid leak. The amount of liquid that drips downward is approximately 2-3% of the amount of liquid sprayed, regardless of whether the electrodes are individually or commonly provided. However, when the electrodes are commonly provided, the liquid from the multiple nozzles drips concentratedly at the bottom of the electrode, making the amount of liquid appear larger than when the electrodes are individually provided.

In order to solve the above problems, the induction charging type electrostatic sprayer of the first invention comprises:
a plurality of nozzles arranged in a row in one direction, which eject liquid in the form of droplets;
At least one electrode extending in the one direction;
an electrode support portion that supports the at least one electrode so as to be close to an outer periphery of a diffusion range of the droplets ejected from each of the plurality of nozzle portions;
An induction charging type electrostatic spraying device configured to inductively charge the droplets by applying a high voltage between the liquid and the electrode,
The nozzle portion is configured to spread and eject the droplets in a substantially elliptical shape having a major axis extending in the one direction.

The number of electrodes is not particularly limited, but may be one electrode located close to the outer periphery on one side of the droplet diffusion range, or two electrodes located close to the outer periphery on both sides of the droplet diffusion range.

With this configuration, the nozzle portion is configured to spread and spray the droplets in a generally elliptical shape having a major axis extending in the one direction, which is the extension direction of the electrode. Therefore, the flatter the generally elliptical shape (the longer the major axis relative to the minor axis of the generally elliptical shape), the less the effect on the charging efficiency of the droplets due to the increase or decrease in the spray angle from the nozzle portion in the minor axis direction has on the charging efficiency of the droplets, compared to when the droplets are sprayed in a circular shape. (1) Since the increase or decrease in the spray angle from the nozzle portion in the minor axis direction is small, the effect on the charging efficiency of the droplets due to the increase or decrease in the spray angle is small, and (2) even if a circular ring portion is not provided so as to be close to the outer periphery of the droplet diffusion range, the electrode can be placed close to the outer periphery of the droplet diffusion range, and the absence of the circular ring portion allows for flexible adjustment of the number and position of the nozzle portions in the one direction.

The induction charging type electrostatic spraying device of the second invention is the same as the first invention,
In one embodiment, the nozzle portion has an ejection hole from which the droplets are ejected, the ejection hole being provided at the tip of a small protrusion formed to protrude in the ejection direction of the droplets.

With this configuration, the electric field lines from the electrode to the nozzle portion can be concentrated at the small protrusion, allowing the droplets ejected from the ejection hole to be efficiently charged.

The induction charging type electrostatic spraying device of the third invention is the device of the first or second invention,
In this embodiment, the electrode has a surface extending in a direction substantially perpendicular to the direction in which the droplets are ejected from the nozzle portion.

This configuration makes it possible to form electric lines of force that extend linearly from the entire surface extending in a direction approximately perpendicular to the direction in which the droplets are ejected toward the nozzle, and it is believed that this makes it possible to effectively charge the droplets ejected from the nozzle (particularly those heading outside the diffusion range).

The fourth invention is an induction charging type electrostatic spraying device according to any one of the first to third inventions,
In this embodiment, the electrode has a surface extending substantially parallel to the direction in which the droplets are ejected from the nozzle portion.

This configuration makes it possible to form electric field lines that extend in a curved line from the entire surface extending approximately parallel to the ejection direction of the droplets, passing through the droplet diffusion range, toward the nozzle section, and is thought to effectively charge the droplets ejected from the nozzle section (particularly those heading toward the inside of the diffusion range).

The induction charging type electrostatic spraying device of the fifth invention is any one of the first to fourth inventions,
In this embodiment, the electrode support portion includes a leakage prevention portion provided on a surface between an electrode support side and a counter-electrode support side that support the electrode, and that prevents leakage between the two support sides.

This configuration prevents the potential of the electrode or the high-potential portion electrically connected to it from leaking through the electrode support portion.

The sixth invention provides an induction charging type electrostatic spraying device according to the fifth invention,
In this embodiment, the leakage prevention unit includes a heater that dries the droplets adhering to the leakage prevention unit.

This configuration prevents electrical leakage caused by the liquid film formed by the accumulation of the droplets.

The seventh invention is an induction charging type electrostatic spraying device according to the fifth or sixth invention,
the plurality of nozzle sections include a plurality of nozzle section sets, each set consisting of a nozzle section that sprays in one of two opposite directions and a nozzle section that sprays in the other, and the plurality of nozzle section sets are arranged in a row on a single nozzle pipe section that extends in the one direction, and are configured to spray the liquid supplied through the nozzle pipe section as droplets,
An example is given in which the electrode and its electrode support part for the nozzle group that sprays in one of the two opposing directions, and the electrode and its electrode support part for the nozzle group that sprays in the other direction, are arranged so that they are approximately point-symmetrical with respect to each other around the central axis when viewed from the direction of the central axis of the nozzle part.

This configuration allows multiple nozzles to be compactly arranged on a single nozzle pipe so that they spray in the two opposite directions, thereby preventing uneven spraying caused by the nozzles being too close to the crops.

The eighth invention of the induction charging type electrostatic spraying device is any one of the first to seventh inventions,
The one direction is a substantially vertical direction,
An example embodiment is provided in which a drip-proof section is provided at a height position midway between at least one pair of adjacent nozzle sections, which receives liquid falling down the electrode and directs it into the spray sprayed from the nozzle section below.

The at least one set of adjacent nozzle sections is not particularly limited, but may include, for example, the lowest set of adjacent nozzle sections. This is because the drip-proof section can collect the largest amount of liquid that falls along the electrode. It may also be provided between adjacent nozzle sections higher up, allowing the liquid to be dispersed among multiple drip-proof sections and collected in small amounts, making it easier for the liquid to mix into the spray when it falls toward it.

The intermediate height position is not particularly limited, but it is preferable to set it at a position where it is unlikely to come into contact with the spray ejected from the nozzles above and below it. Furthermore, the intermediate height position may be configured to be adjustable.

The material of the components of the drip-proof section is not particularly limited, but may be a hard material or a flexible material. A flexible material will have a high degree of adhesion to the electrode, improving the recovery effect of the liquid that trickles down the electrode.

With this configuration, the charged droplets ejected from the nozzle are attracted to the electrode, accumulating and turning into liquid. However, the drip-proof section is configured to catch the liquid that falls down the electrode, reducing the amount of liquid that falls from the bottom of the electrode to the ground or floor and goes to waste. Furthermore, because the section is configured to direct the liquid into the spray ejected from the nozzle section below, the liquid can be propelled in the direction of the target along with the spray, allowing for effective use of the liquid.

The ninth invention provides an induction charging type electrostatic spraying device according to the eighth invention,
An example embodiment is shown in which the drip-proof portion includes a base end portion that is attached to the electrode at a height position midway and receives the liquid from the electrode, at least one drop portion that drops the liquid, and a slope that causes the liquid to flow down from the base end portion to the drop portion.

The base end is not particularly limited, but examples include a configuration in which the base end receives the liquid from a portion or all of the periphery of the electrode. It is not necessary to receive the liquid from all of the periphery of the electrode, but receiving the liquid from all of the electrode is preferable, as this has the effect of reducing waste of the liquid.

The angle of the inclined surface is not particularly limited, but an example is one in which it is angled downward from the horizontal by 15 to 75 degrees. This is because an angle smaller than 15 degrees will impede the flow of the liquid, and an angle larger than 75 degrees will cause the liquid to float off the inclined surface when there is a large amount of liquid, reducing the guiding effect of the inclined surface. The angle of the inclined surface may also be adjustable.

The drop section is not particularly limited, but examples include a case where the liquid drops from the edge of a member that constitutes the drop section, or a case where the liquid drops from a hole in the member. The drip-proof section may be provided with multiple drop sections. This allows the liquid to be dispersed into multiple parts and drop in small amounts at a time.

An example of the drop section is one in which the liquid drops from the leading edge of the member that makes up the drop section, and the width narrows toward the leading edge. This allows the liquid to fall in a concentrated manner toward the target below.

This configuration allows the drip-proof section of the eighth invention to be realized with a simple configuration.

The tenth invention provides an induction charging type electrostatic spraying device according to the ninth invention,
In one embodiment, any one of the at least one drop portions is configured to drop the liquid substantially directly above the center line of the spray ejected from the lower nozzle portion.

With this configuration, the liquid collected by the drip-proof section can be effectively sprayed in the direction of the target along with the spray.

The eleventh invention provides an induction charging type electrostatic spraying device according to the ninth or tenth invention,
In one embodiment, the inclined surface has a wall on its side edge that guides the liquid so that it flows toward the drop portion.

With this configuration, the wall allows the liquid to flow toward the drop section without leakage.

The induction charging type electrostatic spraying device of the twelfth invention is any one of the ninth to eleventh inventions,
In this embodiment, the inclined surface has a recess or a protrusion on the upper surface thereof that guides the liquid so that it flows toward the drop portion.

With this configuration, the flow of the liquid toward the drop portion can be controlled by the recessed portions (e.g., recessed grooves, recessed points, etc.) or protruding portions (e.g., protruding ridges, protruding points, etc.).

The induction charging electrostatic sprayer of the present invention minimizes the impact of increasing or decreasing the spray angle on the charging efficiency of the droplets, and allows for flexible adjustment of the number and position of nozzles.

1 is a perspective view of an induction charging type electrostatic spraying device according to a first embodiment of the present invention; 2A and 2B are diagrams showing the electrostatic spraying device, in which FIG. 2A is a front view and FIG. 2B is a side view. FIG. 3A is a cross-sectional plan view of the electrostatic spraying device, showing the positional relationship between the spray nozzle and the electrode, and FIG. 3B is a view showing the support structure of the electrode by the electrode support portion. FIG. 2 is a circuit diagram for high voltage supply and heater control of the electrostatic spraying device. FIG. 10 is a perspective view of an induction charging type electrostatic spraying device according to a second embodiment of the present invention. 2A and 2B are diagrams showing the electrostatic spraying device, in which FIG. 2A is a front view and FIG. 2B is a side view. FIG. FIG. 10 is a perspective view of an induction charging type electrostatic spraying device according to a third embodiment of the present invention. 2A and 2B are diagrams showing the electrostatic spraying device, in which FIG. 2A is a front view and FIG. 2B is a side view. FIG. FIG. 10 is a perspective view of an induction charging type electrostatic spraying device according to a fourth embodiment of the present invention. FIG. 2 is an enlarged front view of a portion of the electrostatic spraying device. FIG. FIG. 2 is an exploded perspective view of the drip-proof portion of the electrostatic spraying device. 10A to 10C are diagrams showing three modified examples of the drip-proof part. 1 is a plan view showing a pair of left and right electrostatic spraying units of an induction charging type electrostatic spraying device according to a first background art. FIG. FIG. 10 is a circuit diagram of a high voltage supply circuit of an electrostatic spraying device according to the second background art. 10A and 10B are diagrams showing an electrostatic spraying device for an agricultural vehicle according to a third background art, in which FIG. 10A is a rear view and FIG.

1 to 5 show an induction-charging electrostatic sprayer 1 according to a first embodiment of the present invention. This electrostatic sprayer 1 is mounted on the front end of a vehicle (not shown) capable of traveling through a field. It includes a single nozzle 2 extending vertically, a plurality of nozzles 3 arranged vertically relative to the nozzle 2 and spraying liquid as droplets, a plurality of electrodes 5 extending vertically, an electrode support 6 supporting the electrodes 5 adjacent to the outer periphery of the dispersion range of the droplets sprayed from each of the nozzles 3, a high-voltage generation circuit 7 generating a high voltage, a high-voltage cable 8 supplying the high voltage between the liquid and the electrode 5, a heater control circuit 11 for controlling a heater 10 provided in a leakage prevention section (described below) of the electrode support 6, and a heater cable 12 supplying heater control power output by the heater control circuit 11 to the heater 10. The electrostatic sprayer 1 is configured to inductively charge the droplets by applying a high voltage between the liquid and the electrode 5. In each diagram, arrow F points toward the front of the aircraft.

The multiple nozzle units 3 include a plurality of nozzle unit sets, each set consisting of one that sprays in one of two opposing directions (left and right in this example) and one that sprays in the other. These nozzle unit sets (five in this example) are aligned along a single nozzle tube 2 that extends vertically, and are configured to spray droplets of liquid supplied through the nozzle tube 2. In this example, the nozzle tube 2 is made of a conductive metal, and the liquid is connected to ground via the nozzle tube 2. As shown in Figure 4(a), each nozzle unit 3 has an ejection hole 13 from which the droplets are ejected located at the tip of a small protrusion 14 that protrudes in the direction of droplet ejection. The droplets are ejected through the ejection hole 13 in a generally elliptical shape with a major axis parallel to the vertical direction. The specific shape of the small protrusions 14 is not particularly limited, but an example is an approximately hemispherical shape with a diameter of 2.0 to 2.2 mm when viewed from the front of the nozzle portion 3 and a height of 1.2 to 1.4 mm when viewed from the side. In this example, the spray from the nozzle holes 13 is ejected at an angle of approximately 80° vertically (wide angle A1, see Figure 2(a)) and an angle of approximately 20° horizontally (narrow angle A2, see Figure 4(a)), thereby spreading the droplets into the approximately elliptical shape. The ratio of wide angle A1 to narrow angle A2 is preferably 4 or greater, and more preferably 8 or greater. This is because a ratio of less than 4 makes the spray more likely to contact the electrode 5, which requires a greater distance between the electrode 5 and the nozzle portion 3 to prevent this. Furthermore, changing the spray direction makes the spray distance from the electrode 5 more likely to change. A ratio of 8 or greater makes it easier to maintain a constant distance between the electrode 5 and the spray, thereby minimizing the impact of changing the spray direction.

Two electrodes 5 are provided for each nozzle group (in this example, five nozzle groups 3 constitute a nozzle group) that sprays in each of the two opposing directions. As shown in FIG. 4(a), the two electrodes 5 for each nozzle group are positioned on either side of the diffusion range of droplets ejected from the nozzle group in a plan view, and as shown in FIG. 4(b), are electrically connected by connecting metal connectors 4 that serve as conductors. Each electrode 5 has a generally L-shaped cross section, with a first surface 5a extending generally perpendicular to the direction in which droplets are ejected from the nozzle group 3, and a second surface 5b integrally formed on the nozzle side edge of the first surface 5a and extending generally parallel to the direction in which droplets are ejected from the nozzle group 3. Although not particularly limited, in the configuration of the electrodes 5 in this example, as shown in Figure 4(a), in plan view, the distance L1 from the tip of the nozzle portion 3 to the two electrodes 5 is in the range of 9 to 15 mm, the length L2 of the second surface 5b is in the range of 5 to 15 mm, and the distance L3 between the second surfaces 5b of the two electrodes 5 is in the range of 23 to 30 mm.

The electrode support units 6 are attached to the top and bottom of the two electrodes 5 provided for each nozzle group, respectively, and are configured to support the two electrodes 5 relative to the nozzle tube unit 2. Each electrode support unit 6 includes an electrode support side that supports the electrode 5 and a nozzle tube support side as the opposite electrode support side. A leakage prevention unit 16 is provided on the surface between the two support sides to prevent electrical leakage between the two support sides. In this example, the leakage prevention unit 16 is composed of an annular recess (not shown) extending to divide the surface and a cylindrical heater 10 attached inside the annular recess. At least the surfaces of these components are made of an electrically insulating material. In this example, the electrode support unit 6 is formed in a cylindrical shape from the electrode support side to the nozzle tube support side, and a high-voltage cable 8 for supplying high voltage to the electrode 5 can be routed within the cylinder. The leakage prevention unit 16 is equipped with a heater 10 that dries the liquid droplets attached to it.

As shown in Figure 3, the two electrodes 5 and two electrode support members 6 for the nozzle group spraying in one of the two opposing directions, and the two electrodes 5 and two electrode support members 6 for the nozzle group spraying in the other direction, are positioned so that they are approximately point-symmetrical about the central axis of the nozzle section 2 when viewed from the direction of the central axis (i.e., in a plan view).

Next, the electrical system of the electrostatic sprayer 1 of this example will be described. As shown in FIG. 5, the high voltage generated by the high-voltage generating circuit 7 is applied between the electrode 5 and the liquid via a high-voltage cable 8 inserted into the cylinder of the electrode support portion 6. Furthermore, the power for heater control output by the heater control circuit 11 is supplied to each heater 10 via a heater cable 12.

In the induction charging electrostatic sprayer 1 of this example configured as described above, the nozzle portion 3 is configured to spray the droplets in a generally elliptical shape having a major axis extending in the one direction, which is the extension direction of the electrode 5. Therefore, the flatter the generally elliptical shape (the longer the major axis of the generally elliptical shape is relative to the minor axis of the generally elliptical shape), the less the droplets are sprayed in a circular shape. (1) When the spray angle from the nozzle portion 3 decreases, the gap between the outer periphery of the droplet dispersion range and the electrode 5 becomes relatively small, thereby reducing the decrease in the droplet charging efficiency. (2) Even if a ring portion is not provided so as to be close to the outer periphery of the droplet dispersion range, the electrode 5 can be placed close to the outer periphery of the droplet dispersion range. The absence of such a ring portion allows for flexible adjustment of the number of nozzle portions 3 and their positions in the one direction.

In addition, the nozzle portion 3 has an ejection hole 13 from which the droplets are ejected, located at the tip of a small protrusion 14 that protrudes in the direction in which the droplets are ejected. This configuration allows the electric field lines from the electrode 5 to the nozzle portion 3 to be concentrated at the small protrusion 14, allowing the droplets ejected from the ejection hole 13 to be efficiently charged.

The electrode 5 also has a first surface 5a that extends in a direction approximately perpendicular to the direction in which the droplets are ejected from the nozzle portion 3. This configuration makes it possible to form electric lines of force that extend linearly from the entire first surface 5a, which extends in a direction approximately perpendicular to the direction in which the droplets are ejected, toward the nozzle portion 3, and is thought to effectively charge the droplets ejected from the nozzle portion 3 (particularly those heading outside the diffusion range).

The electrode 5 also has a second surface 5b that extends approximately parallel to the direction in which the droplets are ejected from the nozzle portion 3. This configuration makes it possible to form electric field lines that extend in a curved manner from the entire second surface 5b, which extends approximately parallel to the direction in which the droplets are ejected, through the droplet diffusion range toward the nozzle portion 3, and is thought to effectively charge the droplets ejected from the nozzle portion 3 (particularly those heading toward the inside of the diffusion range).

The electrode support part 6 also includes a leakage prevention part 16 that is provided on the surface between the electrode support side that supports the electrode 5 and the non-electrode support side, preventing leakage between the two support sides. This configuration makes it possible to prevent leakage of the potential of the electrode 5 or the high-potential side that is electrically connected to it through the electrode support part 6.

In addition, the leakage prevention unit 16 is exemplified as having a heater 10 that dries the droplets attached to it. This configuration makes it possible to prevent leakage of electricity caused by the liquid film formed by the accumulation of the droplets.

Furthermore, the multiple nozzle units 3 include multiple nozzle unit sets, with one set spraying in one of two opposing directions and the other spraying in the other. These multiple nozzle unit sets are arranged in a row on a single nozzle tube 2 extending in the same direction and are configured to spray the liquid supplied through the nozzle tube 2 as droplets. The electrode 5 and its electrode support 6 for the nozzle unit set spraying in one of the two opposing directions and the electrode 5 and its electrode support 6 for the nozzle unit set spraying in the other are positioned so that they are approximately point-symmetrical about the central axis of the nozzle tube 2 when viewed from the direction of the central axis. This configuration allows multiple nozzle units 3 to be compactly arranged on a single nozzle tube 2 so that they spray in the two opposing directions, thereby reducing the occurrence of uneven spraying due to the proximity of the crop and the nozzle units 3.

Next, Figures 6 to 8 show a second embodiment of the present invention. This induction charging type electrostatic sprayer 51 differs from the first embodiment mainly in the following respects. Therefore, parts that are common to the first embodiment are designated by the same reference numerals and redundant explanations will be omitted.

The electrostatic spray device 51 in this example is attached to a handheld grip 52 and is configured to spray in one direction.

The nozzle section 2 has five nozzle sections 3 arranged in a row at intervals along the length of the nozzle section 2 as a nozzle section group.

The electrode support portion 6 is provided on one side of the tip end of the nozzle portion 2 and on the side directly opposite the one side of the base end.

The electrodes 5 are composed of two metal rods that act as conductors, and are physically integrated and electrically connected by connecting pieces 53 made of metal at the tip and base of the nozzle tube 2, respectively. One electrode 5 at the tip of the nozzle tube 2 and the other electrode 5 at the base of the nozzle tube 2 are supported by electrode support parts 6. To reduce weight, the connecting pieces 53 may be omitted, and both electrodes 5 may be connected to high-voltage cables 8, in which case the high-voltage cables 8 are connected to the respective electrodes via the electrode support parts 6, or the high-voltage cables 8 are connected to both electrodes 5 via either one of the electrode support parts 6.

An extension nozzle section 55 is connected to the base end of the nozzle section 2, and a grip section 52 is provided at the base end of the extension nozzle section 55.

The induction charging type electrostatic sprayer 51 of this example can also achieve the same effects as the first embodiment.

Next, Figures 9 to 11 show a third embodiment of the present invention. This induction charging type electrostatic sprayer 61 differs from the first embodiment mainly in the following respects. Therefore, parts that are common to the first embodiment are designated by the same reference numerals and redundant explanations will be omitted.

The electrostatic spraying device 61 of this example is equipped with a pair of left and right shields 62 made of an electrically insulating material, located forward in the direction of travel of the vehicle to which it is attached. The shields 62 of this example are formed as plates extending in the vertical direction, with the upper and lower portions supported by the nozzle section 2 via mounting portions 62a. Furthermore, the shields 62 of this example are arranged so that, in a plan view, the normal direction of the plate surface is tilted outward in the left-right direction relative to the spray direction of the nozzle section 3, thereby covering the front side of the electrode 5 (the side parallel to the spray direction of the nozzle section 3) and the outer side of the electrode in the minor axis direction of the approximately elliptical shape. The configuration of the shields 62 is not limited to this, and they may be configured to cover only the front side of the electrode 5 (the side parallel to the spray direction of the nozzle section 3) or only the outer side of the electrode 5 in the minor axis direction of the approximately elliptical shape. This shield 62 prevents crops, weeds, etc. from coming into contact with the electrode 5 during spraying, which could cause a drop in the potential of the electrode 5 and prevent the potential difference between the electrode 5 and the liquid from being maintained, resulting in electrostatic spray failure. This allows for stable electrostatic spraying. In this example, the electrostatic sprayer 61 is configured so that the nozzle 3 spreads and sprays the liquid droplets in a roughly elliptical shape with the major axis extending vertically. The minor axis of the roughly elliptical shape extends horizontally, narrowing the spray angle. This reduces the horizontal spread of the spray in front of the electrode 5 compared to conventional circular sprays. Therefore, the shield 62 can be configured to provide greater horizontal shielding in front of the electrode 5, improving the effectiveness of preventing crops, etc. from coming into contact with the electrode 5.

The pair of left and right electrodes 5 provided for the nozzle group are physically integrated by connecting the upper and lower ends to each other with connecting pieces 63. Note that the connecting pieces 63 may be omitted to reduce weight.

The induction charging type electrostatic sprayer 61 of this example can achieve the same effects as the first embodiment, and can also achieve the effects of the unique configuration of this example described above.

Next, Figures 12 to 16 show a fourth embodiment of the present invention. This induction charging type electrostatic sprayer 71 differs from the first embodiment mainly in the following respects. Therefore, parts that are common to the first embodiment are designated by the same reference numerals and redundant explanations will be omitted.

As shown in Figures 12 to 14, the induction charging electrostatic sprayer 71 of this example is equipped with a drip-proof section 72 located at a height midway between two pairs of adjacent nozzle sections 3, which receives the liquid L falling down the electrode 5 and directs it toward the spray S sprayed from the nozzle section 3 below. With this configuration, charged droplets sprayed from the nozzle section 3 are attracted to the electrode 5 and accumulate to form liquid L. However, since the drip-proof section 72 is configured to receive the liquid L falling down the electrode 5, it is possible to reduce the amount of liquid L that falls from the bottom of the electrode 5 to the ground or floor and is wasted. Furthermore, since the section is configured to direct the liquid L toward the spray S sprayed from the nozzle section 3 below, it is possible to propel the liquid L along with the spray S toward the target, thereby enabling effective use of the liquid L.

One of the two pairs of adjacent nozzle parts 3 is the pair of adjacent nozzle parts 3 at the bottom. This allows the drip-proof part 72 to collect the largest amount of liquid L that falls along the electrode 5. The other of the two pairs is the pair of adjacent nozzle parts 3 that is higher than the first pair. This allows the liquid L to be dispersed among multiple drip-proof parts 72 and collected in small amounts, making it easier for the liquid L to mix into the spray S when it falls toward it.

In this example, the intermediate height position is approximately halfway between adjacent nozzle units 3. This is because this approximately halfway position is unlikely to come into contact with the spray S sprayed from the nozzle units 3 above and below it.

In this example, the components of the drip-proof section 72 are made of a hard metal, but this is not limited to this and a flexible material may also be used. Using a flexible material will provide better adhesion to the electrode 5, improving the recovery effect of the liquid L that trickles down the electrode 5.

In this example, the drip-proof portion 72 is attached to the electrode 5 at the intermediate height position and includes a base end 73 that receives the liquid L from the electrode 5, a drop portion 74 that drops the liquid L, and a slope 75 that allows the liquid L to flow down from the base end 73 to the drop portion 74. In this example, as shown in Figures 14 and 15, the drip-proof portion 72 is made up of two plates 72a, 72b secured by two screws 72c that serve as securing means, and is secured to the electrodes 5 on both sides at two points by screws 72d that also serve as securing means. This configuration allows for a simple drip-proof portion 72 to be realized at an intermediate height position between adjacent nozzle portions 3, receiving the liquid L that falls down the electrodes 5 and allowing it to fall into the spray S sprayed from the nozzle portion 3 below.

In this example, the base end 73 is configured to receive all of the liquid L around the electrode 5, which is formed in a roughly L-shape in a plan view, at portions 73a, 73b, 73c, and 73d. It is not necessary to receive all of the liquid L around the electrode 5, but receiving all of the liquid L, as in this example, is preferable because it is more effective at reducing waste of liquid L.

In this example, the angle of the inclined surface 75 is set at 45 degrees downward from the horizontal. This angle effectively allows the liquid L to flow easily while also guiding the liquid L. The angle of the inclined surface 75 may be configured to be adjustable.

In this example, the drop portion 74 is the edge portion on the tip side of the inclined surface 75, but this is not limited to this and it may be provided at multiple locations on the inclined surface 75. This allows the liquid L to be dispersed into multiple parts and drop in small amounts at a time.

In addition, in this example, the drop section 74 is formed to become narrower as it approaches the tip. This allows the liquid L to fall in a concentrated manner toward the target below.

Furthermore, in this example, the drop section 74 is configured to drop the liquid L approximately directly above the center line of the spray S ejected from the nozzle section 3 below. With this configuration, the liquid L collected by the drip-proof section 72 can be effectively scattered in the direction of the spray target along with the spray.

The drip-proof portion 72 can also be modified as follows.
(a) An aspect in which the inclined surface 75 is provided with a wall 75a on its side edge to guide the liquid L toward the drop portion 74 (see FIG. 16(a)). According to this configuration, the wall 75a allows the liquid L to flow toward the drop portion 74 without leakage.

(b) An example is shown in which the inclined surface 75 has a recess or protrusion on its upper surface that guides the liquid L to flow toward the drop portion 74 (see Figure 16 (b)). In the figure, a groove as a recess or a ridge as a protrusion is provided in the center of the inclined surface 75 at the position indicated by the two-dot chain line. Alternatively, the position indicated by the two-dot chain line in the figure may be bent in a V shape to form a groove. With this configuration, the flow of the liquid L toward the drop portion 74 can be controlled by the recess or protrusion.

(c) In an electrostatic spraying device in which one electrode 5 is provided for multiple nozzles 3 arranged in a vertical row, the drip-proof section 72A of this example is divided into two parts in the middle and is attached to the electrode 5 (see Figure 16 (c)). This configuration also achieves the same effects as the drip-proof section 72 of this example.

The induction charging type electrostatic sprayer 71 of this example, configured as described above, can achieve the same effects as the first embodiment, as well as the effects of the unique configuration of this example described above. With the electrostatic sprayer 71 of this example, the action and effect of the drip-proof section 72 has made it possible to reduce the amount of liquid L dripping downward from the lower end of the electrode 5 to approximately 0.2% of the amount of liquid being sprayed.

The present invention is not limited to the above-described embodiment, and can be embodied by making appropriate modifications within the scope of the invention, for example, as follows.
(1) One electrode 5 is provided for each nozzle group. The electrode 5 for each nozzle group is disposed on only one side of the diffusion range of droplets ejected from the nozzle group in a plan view. Figure 16(c) is an enlarged partial view showing the positional relationship between the nozzles 3 and the electrodes 5 when the nozzles 3 are arranged in a vertical row, illustrating an example of this modification.
(2) The number of electrode support portions 6 that support the electrodes 5 can be increased or decreased as needed.
(3) The shape of the electrode 5 may be appropriately changed. For example, the electrode 5 may be formed into a rectangular shape (hollow or solid) in a plan view, or may have only a surface extending in a direction substantially perpendicular to the ejection direction of the droplets from the nozzle portion 3, or may have only a surface extending substantially parallel to the ejection direction of the droplets from the nozzle portion 3.

DESCRIPTION OF SYMBOLS 1 Induction charging type electrostatic spraying device 2 Spray pipe portion 3 Nozzle portion 4 Connection piece 5 Electrode 5a First surface 5b Second surface 6 Electrode support portion 7 High voltage generating circuit 8 High voltage cable 10 Heater 11 Heater control circuit 12 Heater cable 13 Spray hole 14 Small protrusion portion 16 Leakage prevention portion 51 Induction charging type electrostatic spraying device 52 Grip portion 53 Connection piece 55 Extension nozzle portion 61 Induction charging type electrostatic spraying device 62 Shield 62a Mounting portion 63 Connection piece 71 Induction charging type electrostatic spraying device 72 Drip-proof portion 72A Drip-proof portion 72a Plate piece 72b Plate piece 72c Screw 72d Screw 73 Base end portion 73a Liquid receiving portion 73b Liquid receiving portion 73c Liquid receiving portion 73d Liquid receiving portion 74 Falling part 75 Slope 75a Wall A1 Wide angle A2 Narrow angle L Liquid S Spray

Claims (5)

a plurality of nozzles arranged in a row in one direction, which eject liquid in the form of droplets;
At least one electrode extending in the one direction;
an electrode support portion that supports the at least one electrode so as to be close to an outer periphery of a diffusion range of the droplets ejected from each of the plurality of nozzle portions;
An induction charging type electrostatic spraying device configured to inductively charge the droplets by applying a high voltage between the liquid and the electrode,
the nozzle portion is configured to spread and eject the droplets in a substantially elliptical shape having a major axis extending in the one direction,
The one direction is a substantially vertical direction,
An induction charging type electrostatic spraying device having a drip-proof section at a height position midway between at least one pair of adjacent nozzle sections that receives liquid falling down the electrode and drops it into the spray sprayed from the nozzle section below . The induction charging type electrostatic spray device described in claim 1, wherein the drip-proof portion is attached to the electrode at a height position midway and comprises a base end portion that receives the liquid from the electrode, at least one drop portion that drops the liquid, and a slope that causes the liquid to flow down from the base end portion to the drop portion. 3. The induction charging type electrostatic spraying device according to claim 2 , wherein any one of the at least one drop sections is configured to drop the liquid directly above the center line of the spray ejected from the lower nozzle section. 4. The induction charging type electrostatic spraying device according to claim 2 , wherein the inclined surface is provided with a wall on its side edge for guiding the liquid so that the liquid flows toward the drop portion. The induction charging type electrostatic spraying device according to any one of claims 2 to 4, wherein the inclined surface has a recess or a protrusion on its upper surface that guides the liquid to flow toward the drop portion.