Induction charging type electrostatic sprayer

Abstract

To reduce an influence on charging efficiency of droplets by increase / decrease in a spray angle, and flexibly adjust the number of nozzle parts to be arranged and the positions of the nozzle part.SOLUTION: An induction charging type electrostatic sprayer 1 includes a plurality of nozzle parts 3 which are aligned in one direction and jet a liquid as droplets, at least one electrode 5 extending in the one direction, and electrode support parts 6 for supporting at least the one electrode 5 so as to be brought into close contact with the outer periphery of a diffusion range of the droplets jet from each of the plurality of nozzle parts 3, and is configured to induce and electrify the droplets by applying a high voltage between the liquid and the electrode 5. The nozzle parts 3 are configured to jet the droplets while being diffused in substantially an elliptical shape having a major axis extending in the one direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an induction charging type electrostatic sprayer that uses static electricity to spray liquids such as chemicals. [Background technology]

[0002] As a first background art, an induction charging type electrostatic sprayer described in Patent Document 1 is exemplified. As shown in Fig. 17, this induction charging type electrostatic sprayer 110 includes a pair of electrostatic spraying units 101, 101 that spray droplets to the left and right, respectively. The electrostatic spraying 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 toward the tip end side of the nozzle unit 111 at a distance to the side of the nozzle unit 111, a substantially annular electrode 105 disposed on the tip end of the electrode support shaft 102, and a leakage prevention unit 104 provided on the surface between the base end of the electrode support shaft 102 and the electrode 105. The electrostatic spraying unit 101 is configured to inductively charge the droplets by applying a high voltage between the liquid and the electrode 105.

[0003] The second background art is exemplified by the electrostatic spraying device described in Patent Document 2. As shown in Fig. 18, a high-voltage supply circuit 202 in this electrostatic spraying device 201 supplies a high voltage from a high-voltage generation unit 203 to each of 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 droplets to prevent electrical leakage due to droplets adhering to the electrostatic spraying unit 204, it is also necessary to supply power from a heater control circuit 207 to each heater 205 via a heater power supply circuit 206.

[0004] An example of a third background art is the electrostatic spraying device for an agricultural vehicle described in Patent Document 3. As shown in Fig. 19, this electrostatic spraying device is configured such that rod-shaped front and rear high-voltage conductors 361, 361 extending in the left-right direction are arranged below spray nozzles 303, ... which are provided at approximately predetermined intervals on a spray boom 304 extending in the left-right direction, a high voltage is applied to the front and rear high-voltage conductors 361, 361, and only the front and rear high-voltage conductors 361, 361 located below the spray nozzles 303, ... of the spray boom 304 are configured as annular portions 361a, ... which move away from the spray nozzles 303, ... in the front-rear and left-right directions in a plan view, and adjacent annular portions 361a, ... on the left and right are connected by linear portions extending in the left-right direction. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-163154 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-130581 [Patent Document 3] Japanese Patent Application Laid-Open No. 2010-104321 Summary of the Invention [Problem to be solved by the invention]

[0006] In the device according 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, and therefore the distance from the nozzle tube 142 that supplies the liquid to the tip of the nozzle unit 111 is long, and 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 may 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, but the need for two nozzle tubes 142 poses problems of a complex configuration and increased costs.

[0007] Furthermore, in the device relating to the second background art, since each electrostatic spraying 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, and the more nozzles there are, the more complicated the wiring becomes and the higher the cost becomes, which is a problem.

[0008] In contrast to this second background technology, the electrostatic spraying device relating to the third background technology has high-voltage conductors 361, 361 as common electrodes for multiple spray nozzles 303, ..., and furthermore, circular portions 361a, ... are formed in the high-voltage conductors 361, 361 at positions close to the spray nozzles 303, ... which move away from the spray nozzles 303, ... in the front-to-back and left-to-right directions when viewed in a plane, resulting in the problem that the number of spray nozzles 303 installed and the relative positions of the spray nozzles 303, ... are fixed and cannot be adjusted.

[0009] Furthermore, in both of the background arts, the electrode is formed in a circular ring shape so that the inner circumference is close to the outer circumference of the diffusion range of droplets 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 becomes, resulting in a problem of reduced charging efficiency of the droplets.

[0010] 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 of 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 lower end of the electrode, making the amount of liquid appear larger than when the electrodes are individually provided. [Means for solving the problem]

[0011] In order to solve the above problems, the induction charging type electrostatic sprayer of the first invention is 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 the outer periphery of the 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.

[0012] The electrode 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.

[0013] According to this configuration, the nozzle portion is configured to spread and spray the droplets in an approximately elliptical shape having a major axis extending in the one direction, which is the extension direction of the electrode. Therefore, the flatter the approximately elliptical shape is (the longer the major axis is relative to the minor axis of the approximately elliptical shape), the smaller the increase or decrease in the spray angle from the nozzle portion in the minor axis direction, and therefore the smaller the effect on the charging efficiency of the droplets due to the increase or decrease in the spray angle, compared to when the droplets are sprayed in a circular shape, and (2) the electrode can be placed close to the outer periphery of the dispersion range of the droplets even if a circular ring portion is not provided so as to be close to the outer periphery of the dispersion range of the droplets, and because the circular ring portion does not exist, the number of nozzle portions arranged in the one direction and the positions of the nozzle portions can be flexibly adjusted.

[0014] The induction charging type electrostatic spraying device of the second invention is the same as that of 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.

[0015] According to this configuration, the electric lines of force directed from the electrode to the nozzle portion can be concentrated on the small protrusion portion, and the droplets ejected from the ejection holes can be efficiently charged.

[0016] 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.

[0017] With this configuration, it is possible to form electric field lines 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 portion, and it is believed that this makes it possible to effectively charge the droplets (especially those heading outside the diffusion range) ejected from the nozzle portion.

[0018] 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.

[0019] With this configuration, it is possible to form electric field lines that extend in a curved manner from the entire surface extending approximately parallel to the direction in which the droplets are ejected, through the diffusion range of the droplets, toward the nozzle portion, and it is believed that this makes it possible to effectively charge the droplets ejected from the nozzle portion (especially those heading toward the inside of the diffusion range).

[0020] The fifth invention is an induction charging type electrostatic spraying device according to 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.

[0021] This configuration can prevent the potential of the electrode or the high-potential portion electrically connected thereto from leaking through the electrode support portion.

[0022] The sixth invention is 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.

[0023] This configuration can prevent leakage current from occurring due to the liquid film formed by the accumulation of the droplets.

[0024] 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.

[0025] With this configuration, multiple nozzle sections can be compactly arranged on one nozzle pipe so that they spray in the two opposite directions, thereby preventing uneven spraying due to the crops being too close to the nozzle sections.

[0026] 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.

[0027] The at least one set of adjacent nozzle units is not particularly limited, but may include, for example, a set of adjacent nozzle units at the bottom. This is because the drip-proof unit can collect the largest amount of the liquid that falls down the electrode. It may also be provided between adjacent nozzle units at higher positions, which allows the liquid to be dispersed among multiple drip-proof units and collected in small amounts, making it easier for the liquid to mix into the spray when it falls toward the spray.

[0028] The intermediate height position is not particularly limited, but is preferably set at a position where it is difficult for the sprays ejected from the nozzles above and below it. The intermediate height position may also be configured to be adjustable.

[0029] The material of the components of the drip-proof portion is not particularly limited, but may be a hard material or a flexible material. If a flexible material is used, it will have high adhesion to the electrode, and the recovery effect of the liquid that runs down the electrode can be improved.

[0030] According to this configuration, the charged droplets ejected from the nozzle portion are attracted to the electrode, which accumulates and turns into liquid, but the drip-proof portion is configured to receive the liquid that falls down the electrode, thereby reducing the amount of liquid that falls from the lower end of the electrode to the ground or floor and is wasted, and is configured to fall into the spray ejected from the nozzle portion below, so the liquid can be sent in the direction of the target to be sprayed along with the spray, allowing the liquid to be used effectively.

[0031] The ninth invention of the induction charging type electrostatic spraying device is the eighth invention of the present 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.

[0032] The base end is not particularly limited, but may be configured to receive the liquid from a part or all of the periphery of the electrode. Although it is not necessary to receive the liquid from the entire periphery of the electrode, receiving the entire liquid is preferable because it is more effective in reducing waste of the liquid.

[0033] The angle of the inclined surface is not particularly limited, but an example is one in which it is angled downward from the horizontal at an angle of 15 to 75 degrees. This is because an angle smaller than 15 degrees impairs the flow of the liquid, and an angle larger than 75 degrees causes 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.

[0034] The drop portion is not particularly limited, but examples include a mode in which the liquid drops from an edge portion of a member constituting the drop portion, or a mode in which the liquid drops from a hole provided in the member. The drip-proof portion may be provided with a plurality of drop portions. This allows the liquid to drop in small amounts by dispersing it into multiple parts.

[0035] In addition, the drop portion may be formed so that the liquid drops from the tip edge of the member that constitutes the drop portion and is narrower toward the tip, thereby allowing the liquid to drop in a concentrated manner toward a target below.

[0036] According to this configuration, the drip-proof part according to the eighth aspect of the present invention can be realized with a simple configuration.

[0037] The tenth invention of the induction charging type electrostatic spraying device is 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.

[0038] With this configuration, the liquid collected by the drip-proof portion can be effectively sprayed in the direction of the target to be sprayed together with the spray.

[0039] The induction charging type electrostatic spraying device of the eleventh invention is the ninth or tenth invention, In one embodiment, the inclined surface has a wall on its side edge that guides the liquid to flow toward the drop portion.

[0040] According to this configuration, the wall allows the liquid to flow toward the drop portion without leakage.

[0041] 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.

[0042] According to this configuration, the flow of the liquid toward the drop portion can be controlled by the recessed portion (for example, recessed grooves, recessed points, etc.) or the protruding portion (for example, protruding ridges, protruding points, etc.). [Effects of the Invention]

[0043] According to the induction charging type electrostatic sprayer of the present invention, the effect of increasing or decreasing the spray angle on the charging efficiency of the droplets can be reduced, and the number and positions of the nozzle portions can be flexibly adjusted. [Brief explanation of the drawings]

[0044] [Figure 1] 1 is a perspective view of an induction charging type electrostatic spraying device according to a first embodiment of the present invention; [Figure 2] 2A and 2B are diagrams showing the electrostatic spraying device, in which (a) is a front view and (b) is a side view. [Figure 3] FIG. [Figure 4] 1A is a cross-sectional plan view of the electrostatic spraying device, showing the positional relationship between the spray nozzle and the electrode, and FIG. 1B is a view showing the support structure of the electrode by the electrode support portion. [Figure 5] FIG. 2 is a circuit diagram for high voltage supply and heater control of the electrostatic spraying device. [Figure 6] FIG. 10 is a perspective view of an induction charging type electrostatic spraying device according to a second embodiment of the present invention. [Figure 7] 2A and 2B are diagrams showing the electrostatic spraying device, in which (a) is a front view and (b) is a side view. [Figure 8] FIG. [Figure 9] FIG. 10 is a perspective view of an induction charging type electrostatic spraying device according to a third embodiment of the present invention. [Figure 10] 2A and 2B are diagrams showing the electrostatic spraying device, in which (a) is a front view and (b) is a side view. [Figure 11] FIG. [Figure 12] FIG. 10 is a perspective view of an induction charging type electrostatic spraying device according to a fourth embodiment of the present invention. [Figure 13] FIG. 2 is an enlarged front view of a portion of the electrostatic spraying device. [Figure 14] FIG. [Figure 15] FIG. 2 is an exploded perspective view of the drip-proof portion of the electrostatic spraying device. [Figure 16] 10A to 10C are diagrams showing three modified examples of the drip-proof part. [Figure 17] 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. [Figure 18] FIG. 10 is a circuit diagram of a high voltage supply circuit of an electrostatic spraying device according to the second background art. [Figure 19] 10A and 10B are diagrams showing an electrostatic spraying device of an agricultural vehicle according to the third background art, in which (a) is a rear view and (b) is a plan view. DETAILED DESCRIPTION OF THE INVENTION

[0045] 1 to 5 show an induction charging type 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) that is capable of traveling in a field, and includes a single nozzle 2 extending in one direction (vertical direction), a plurality of nozzles 3 arranged in a vertical line relative to the nozzle 2 and spraying a liquid as droplets, a plurality of electrodes 5 extending vertically, an electrode support 6 that supports the plurality of electrodes 5 so as to be adjacent to the outer periphery of the dispersion range of the droplets sprayed from each of the nozzles 3, a high-voltage generating circuit 7 that generates a high voltage, a high-voltage cable 8 that supplies the high voltage between the liquid and the electrode 5, a heater control circuit 11 that controls a heater 10 provided in a leakage prevention section (described below) of the electrode support 6, and a heater cable 12 that supplies 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 figure, arrow F points to the front of the aircraft.

[0046] The multiple nozzle units 3 include a plurality of nozzle unit assemblies, each of which sprays in one of two opposite directions (left and right in this example) and another of which sprays in the other. The multiple nozzle unit assemblies (five in this example) are arranged in a row on a single nozzle tube 2 extending vertically, and are configured to spray liquid supplied through the nozzle tube 2 as droplets. 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 FIG. 4(a), each nozzle unit 3 is configured such that the nozzle holes 13 from which the droplets are sprayed are located at the tips of small protrusions 14 formed to protrude in the direction in which the droplets are sprayed, and the droplets are sprayed through the nozzle holes 13 in a generally elliptical shape with their major axes parallel to the vertical direction. The specific shape of the small protrusions 14 is not particularly limited, but an example is shown in which they are formed into a roughly 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° in the vertical direction (wide angle A1, see FIG. 2(a)) and an angle of approximately 20° in the horizontal direction (narrow angle A2, see FIG. 4(a)), thereby spreading the droplets into the roughly elliptical shape. The ratio of the wide angle A1 to the narrow angle A2 is preferably 4 or more, and more preferably 8 or more. This is because a ratio of less than 4 makes the spray more likely to contact the electrode 5, and to prevent this, it is necessary to increase the distance between the electrode 5 and the nozzle portion 3. Also, when the spray direction is changed, the distance of the spray from the electrode 5 is more likely to change. A ratio of 8 or more makes it easier to maintain a constant distance between the electrode 5 and the spray, thereby reducing the impact of changing the spray direction.

[0047] 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 arranged on both sides of the diffusion range of droplets ejected from the nozzle group in a plan view, and as shown in FIG. 4(b), they are electrically connected by being linked by metal connecting pieces 4 that serve as conductors. Each electrode 5 has a substantially L-shaped cross section, having a first surface 5a that extends in a direction substantially perpendicular to the ejection direction of the droplets from the nozzle group 3, and a second surface 5b that is integrally formed on the nozzle side edge of the first surface 5a and extends substantially parallel to the ejection direction of the droplets from the nozzle group 3. Although not particularly limited, in the configuration of the electrode 5 of this example, as shown in FIG. 4(a), in a 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.

[0048] The electrode support members 6 are attached to the upper and lower portions 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 2. Each electrode support member 6 includes an electrode support side that supports the electrode 5 and a nozzle tube support side that is the opposite electrode support side. A leakage prevention member 16 is provided on the surface between the two support sides to prevent electrical leakage between the two support sides. The leakage prevention member 16 in this example 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. The electrode support member 6 in this example is cylindrical, extending from the electrode support side to the nozzle tube support side. A high-voltage cable 8 for supplying high voltage to the electrode 5 can be routed within the cylinder. The leakage prevention member 16 is equipped with a heater 10 that dries the droplets adhering to it.

[0049] As shown in Figure 3, the two electrodes 5 and two electrode support parts 6 for the nozzle group that sprays in one of the two opposing directions, and the two electrodes 5 and two electrode support parts 6 for the nozzle group that sprays in the other direction, are arranged so that they are approximately point-symmetrical with respect to each other when viewed from the direction of the central axis of the nozzle part 2 (i.e., when viewed from above).

[0050] 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 part 6. Furthermore, the power for heater control output from the heater control circuit 11 is supplied to each heater 10 via a heater cable 12.

[0051] According to the induction charging electrostatic sprayer 1 of this example configured as described above, the nozzle portion 3 is configured to spread and spray the droplets in an approximately elliptical shape having a major axis extending in the one direction, which is the extension direction of the electrode 5. Therefore, the flatter the approximately elliptical shape is (the longer the major axis is relative to the minor axis of the approximately elliptical shape), the smaller the gap between the outer periphery of the droplet diffusion range and the electrode 5 becomes when the spray angle from the nozzle portion 3 becomes, compared to when the droplets are sprayed in a circular shape, and the decrease in the charging efficiency of the droplets can be made relatively small, and (2) the electrode 5 can be brought close to the outer periphery of the droplet diffusion range even if a circular ring portion is not provided so as to be close to the outer periphery of the droplet diffusion range, and since the circular ring portion does not exist, the number of nozzle portions 3 arranged in the one direction and the position of the nozzle portion 3 can be flexibly adjusted.

[0052] In addition, nozzle portion 3 has ejection holes 13 from which the droplets are ejected, which are provided at the tips of small protrusions 14 formed to protrude in the ejection direction of the droplets. With this configuration, the electric field lines from electrode 5 to nozzle portion 3 can be concentrated at small protrusions 14, and the droplets ejected from ejection holes 13 can be efficiently charged.

[0053] Furthermore, the electrode 5 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. With this configuration, it is 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 it is understood that this makes it possible to effectively charge the droplets ejected from the nozzle portion 3 (particularly those heading toward the outside of the diffusion range).

[0054] Furthermore, the electrode 5 has a second surface 5b that extends substantially parallel to the direction in which the droplets are ejected from the nozzle portion 3. With this configuration, it is possible to form electric lines of force that extend in a curved manner from the entire second surface 5b, which extends substantially parallel to the direction in which the droplets are ejected, through the diffusion range of the droplets toward the nozzle portion 3, and it is understood that this makes it possible to effectively charge the droplets ejected from the nozzle portion 3 (particularly those that head toward the inside of the diffusion range).

[0055] 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, and that prevents leakage between the two support sides. This configuration makes it possible to prevent the potential of the electrode 5 or the high-potential side that is electrically connected to it from leaking through the electrode support part 6.

[0056] In addition, an embodiment is shown in which the leakage prevention unit 16 includes a heater 10 that dries the droplets attached thereto. With this configuration, it is possible to prevent leakage of electricity caused by a liquid film formed by the accumulation of the droplets.

[0057] Furthermore, the multiple nozzle units 3 include multiple nozzle unit sets, each set consisting of one that sprays in one of two opposing directions and one that sprays in the other, and the 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, and the electrode 5 and its electrode support 6 for the nozzle unit set that sprays in one of the two opposing directions and the electrode 5 and its electrode support 6 for the nozzle unit set that sprays in the other are arranged so that they are mutually approximately point-symmetrical about the central axis of the nozzle tube 2 when viewed from the direction of the central axis of the nozzle tube 2. With this configuration, multiple nozzle units 3 can be compactly arranged on a single nozzle tube 2 so that they spray in the two opposing directions, thereby preventing uneven spraying due to the proximity of the crops and the nozzle units 3.

[0058] 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 points. Therefore, parts common to the first embodiment are designated by the same reference numerals and will not be described again.

[0059] The electrostatic spraying device 51 of this example is attached to a grip portion 52 for handholding, and is configured to spray in one direction.

[0060] The nozzle pipe section 2 has five nozzle sections 3 arranged in a row at intervals in the pipe length direction of the nozzle pipe section 2 as a nozzle section group.

[0061] The electrode support portion 6 is provided on one side of the tip end side of the nozzle portion 2 and on the side directly opposite to the one side of the base end side of the nozzle portion 2.

[0062] The electrodes 5 are composed of two metal rods acting as conductors, which are physically integrated and electrically connected by connecting pieces 53 made of metal at the distal and proximal ends of the nozzle section 2, respectively, and one electrode 5 at the distal end of the nozzle section 2 and the other electrode 5 at the proximal end of the nozzle section 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 respective 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.

[0063] An extension nozzle part 55 is connected to the base end side of the nozzle part 2, and a grip part 52 is provided on the base end side of the extension nozzle part 55.

[0064] The induction charging type electrostatic sprayer 51 of this embodiment can also provide the same effects as those of the first embodiment.

[0065] 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 common to the first embodiment are designated by the same reference numerals and will not be described again.

[0066] The electrostatic spraying device 61 of this example is provided with a pair of left and right shields 62 made of an electrically insulating material, located forward in the direction of travel of the machine on which it is mounted. The shields 62 of this example are formed in the shape of plates extending in the vertical direction, and the upper and lower portions are supported by the nozzle unit 2 via mounting portions 62a. The shields 62 of this example are arranged such that, in a plan view, the normal direction of the plate surface is tilted outward in the left-right direction with respect to the spray direction of the nozzle unit 3, thereby covering the front side of the electrode 5 (the side parallel to the spray direction of the nozzle unit 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 thereto, 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 unit 3) or only the outer side of the electrode 5 in the minor axis direction of the approximately elliptical shape. This shield 62 prevents a situation in which crops, weeds, etc. come into contact with the electrode 5 during spraying, causing a drop in the potential of the electrode 5 and an inability to maintain the potential difference between the electrode 5 and the liquid, resulting in electrostatic spray failure. This allows for stable electrostatic spraying. In the electrostatic spraying device 61 of this example, the nozzle portion 3 is configured to spray droplets in a generally elliptical shape with a major axis extending vertically, and the minor axis of the generally elliptical shape extends horizontally, narrowing the spray angle. Therefore, compared to conventional circular sprays, the spray spreads less horizontally in front of the electrode 5. Therefore, the shield 62 can be configured to provide wider horizontal shielding in front of the electrode 5, thereby improving the effectiveness of preventing crops, etc. from coming into contact with the electrode 5.

[0067] 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.

[0068] The induction charging type electrostatic spraying device 61 of this example can also obtain the same effects as those of the first embodiment, and can also obtain the effects due to the configuration unique to this example described above.

[0069] 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 common to the first embodiment are designated by the same reference numerals and will not be described again.

[0070] 12 to 14, the induction charging type electrostatic sprayer 71 of this example is provided with a drip-proof part 72 at a height midway between two pairs of adjacent nozzle parts 3, which receives the liquid L falling down the electrode 5 and causes it to fall into the spray S sprayed from the nozzle part 3 below. With this configuration, the charged droplets sprayed from the nozzle part 3 are attracted to the electrode 5 and accumulate to become liquid L, but since the drip-proof part 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 end of the electrode 5 to the ground or floor and is wasted, and since it is configured to cause it to fall into the spray S sprayed from the nozzle part 3 below, it is possible to send the liquid L along with the spray S in the direction of the target to be sprayed, thereby enabling the liquid L to be used effectively.

[0071] One of the two sets of adjacent nozzle parts 3 is the set of adjacent nozzle parts 3 at the bottom. This is because the largest amount of liquid L that falls down the electrode 5 can be collected by the drip-proof part 72. The other of the two sets is the set of adjacent nozzle parts 3 that is higher than the first set. This is because the liquid L can be dispersed among multiple drip-proof parts 72 and collected in small amounts, which makes it easier for the liquid L to mix into the spray S when it falls into the spray S.

[0072] In this example, the intermediate height position is set to be approximately the midpoint between the adjacent nozzle portions 3. This is because the approximately midpoint is a position where it is difficult for the spray S ejected from the nozzle portions 3 above and below it to come into contact.

[0073] In this example, the material of the components of the drip-proof part 72 is a hard material, but is not limited to metal and may be a flexible material. If a flexible material is used, it will have high adhesion to the electrode 5, and the recovery effect of the liquid L that runs down the electrode 5 can be improved.

[0074] In this example, drip-proof portion 72 is attached to electrode 5 at the intermediate height position and includes a base end 73 that receives liquid L from electrode 5, a drop portion 74 that drops liquid L, and a slope 75 that causes liquid L to flow down from base end 73 to drop portion 74. In this example, as shown in Figures 14 and 15 , drip-proof portion 72 is formed by two plates 72a and 72b fixed with two screws 72c that serve as fixing means, and two locations on the base end are fixed to electrodes 5 on both sides with screws 72d that also serve as fixing means. With this configuration, drip-proof portion 72 can be simply configured to receive liquid L that drops down electrode 5 at an intermediate height position between adjacent nozzle portions 3 and drop it into the spray S sprayed from the nozzle portion 3 below.

[0075] In this example, the base end portion 73 is configured to receive all of the liquid L around the electrode 5, which is formed in a substantially 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 in reducing waste of the liquid L.

[0076] In this example, the angle of the inclined surface 75 is set to 45° downward with respect to the horizontal direction, because this angle can effectively achieve both the ease of flow of the liquid L and the guiding action of the liquid L. The angle of the inclined surface 75 may be configured to be adjustable.

[0077] In this example, the drop portion 74 is the edge portion on the tip side of the inclined surface 75, but is not limited to this and may be provided at multiple locations on the inclined surface 75. This allows the liquid L to be dispersed into multiple parts and dropped in small amounts at a time.

[0078] Furthermore, the width of the drop portion 74 in this example is narrower towards the tip side, which allows the liquid L to fall in a concentrated manner towards the target below.

[0079] Furthermore, in this example, drop portion 74 is configured to drop liquid L substantially directly above the center line of spray S ejected from nozzle portion 3 below. With this configuration, liquid L collected by drip-proof portion 72 can be effectively thrown in the direction of the spray target together with the spray.

[0080] The drip-proof portion 72 can also be modified as follows. (a) An aspect in which the inclined surface 75 has a wall 75a provided 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.

[0081] (b) An example is shown in which the inclined surface 75 has a recess or a protrusion on its upper surface that guides the liquid L to flow toward the drop portion 74 (see FIG. 16(b)). In the figure, a groove as a recess or a ridge as a protrusion is provided at the position indicated by the two-dot chain line in the center of the inclined surface 75. 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 the protrusion.

[0082] (c) In an electrostatic spraying device in which one electrode 5 is provided for a plurality of nozzles 3 arranged in a vertical row, the drip-proof part 72A of the present example is divided into two parts in the middle and is provided on the electrode 5 (see FIG. 16(c)). This configuration also achieves the same effects as the drip-proof part 72 of the present example.

[0083] The induction charging type electrostatic sprayer 71 of this example configured as described above can also achieve the same effects as those of the first embodiment, as well as the effects of the configuration unique to this example described above. With the electrostatic sprayer 71 of this example, the action and effect of the drip-proof part 72 can reduce the amount of liquid L dripping downward from the lower end of the electrode 5 to about 0.2% of the amount of liquid to be sprayed.

[0084] 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 example of this modified example, and is a partially enlarged view showing the positional relationship between the nozzles 3 and the electrodes 5 when the nozzles 3 are arranged in a vertical row. (2) The number of electrode support parts 6 that support the electrodes 5 can be increased or decreased as appropriate. (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 direction in which the droplets are ejected from the nozzle portion 3, or may have only a surface extending substantially parallel to the direction in which the droplets are ejected from the nozzle portion 3. [Explanation of symbols]

[0085] 1. Induction charging type electrostatic sprayer 2 Jet pipe part 3 Nozzle section 4 Connection piece 5 electrodes 5a Front page 5b Second side 6 Electrode support part 7 High voltage generation circuit 8 High Voltage Cables 10. Heater 11 Heater control circuit 12 Heating Cable 13 Spout hole 14 Small protrusion 16 Earth leakage prevention part 51 Induction charging type electrostatic sprayer 52 Grip section 53 Connection piece 55 Extension jet pipe section 61 Induction charging type electrostatic sprayer 62 Shield 62a Mounting part 63 Connection piece 71 Induction charging type electrostatic sprayer 72 Drip-proof section 72A Drip-proof part 72a plate piece 72b plate piece 72c screw 72d screw 73 Proximal end 73a Liquid receiving area 73b Liquid receiving area 73c Liquid receiving area 73d Part that receives fluid 74 Drop Section 75 Slope 75a wall A1 Wide-angle A2 narrow angle L liquid S spray

Claims

1. 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.

2. 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. 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. 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.

5. 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.

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