Electrostatic atomizer

Abstract

To provide an electrostatic atomizer which can suppress generation of spark caused by discharge between a nozzle and an equipotential line adjustment electrode, and a different electrode part such as a coated matter.SOLUTION: An electrostatic atomizer 10 by an electro-spray method includes a liquid atomizing part 20, voltage application means 50 for applying a voltage between the liquid atomizing part 20 and a different electrode part 40, and generating electrostatic force of detaching the liquid in a charged state from a nozzle 22 and atomizing the liquid, an equipotential line adjustment electrode 30 for adjusting the state of an equipotential curve which is formed of a conductive material and appears so as to surround the nozzle 22, and an electrode cover 120 which is formed of the insulation material and covers a surface on at least a tip 30a side of the equipotential line adjustment electrode 30, wherein the equipotential line adjustment electrode 30 is arranged so that a part covering the tip 30a in the electrode cover 120 is positioned at a rear part of the tip in the vicinity of a tip outer periphery of the nozzle 22, and has a same potential as the potential of the liquid atomizing part 20.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to electrostatic spray devices. [Background technology]

[0002] In an electrostatic spraying device, a high voltage is applied between the nozzle and the workpiece, which is the opposite pole to the nozzle. This generates a strong electric field, and due to the influence of this electric field, ions in the liquid gather near the liquid surface at the tip of the nozzle. The ions in the liquid are attracted to the object on the opposing electrode by the force of the electric field. This forms a Taylor cone, in which the liquid surface protrudes in a cone shape with its apex facing the workpiece. Then, at the tip of this Taylor cone, fine droplets are torn off from the Taylor cone and sprayed by the Coulomb repulsion between the ions in the liquid and the force of the electric field. The sprayed droplets are attracted to the workpiece by the force of the electric field and adhere to it. As an example of such an electrostatic spraying device, Patent Document 1 discloses an equipotential line adjustment electrode with the same potential as the nozzle, which is provided near the outer periphery of the tip of the nozzle and behind the tip of the nozzle. By providing the above-mentioned equipotential line adjustment electrode, such an electrostatic spraying device can be made to have a compact configuration that does not get in the way when moving the nozzle, and yet can make the atomized liquid sprayed in a predetermined state. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-87124 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned conventional technology, although there is no problem if the work is performed correctly, if the distance between the nozzle and the workpiece is mistakenly brought too close within a specified distance during spraying, there is a risk of sparks being generated by discharge between the nozzle and the equipotential line adjustment electrode and the workpiece. Also, when a different electrode body having the same potential as the workpiece is used as the different electrode part in addition to the workpiece, if the distance between the nozzle and the different electrode body is mistakenly brought too close within a specified distance, there is a risk of sparks being generated by discharge between the nozzle and the equipotential line adjustment electrode and the different electrode body.

[0005] Therefore, an object of the present disclosure is to provide an electrostatic spray device that can suppress the generation of sparks due to discharge between the nozzle and equipotential line adjustment electrode and opposite polarity parts such as the workpiece. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention is realized as follows. (1) The electrostatic spraying device of the present invention is an electrostatic spraying device using an electrospray method in which a voltage is applied between a liquid spraying section having a nozzle for spraying a liquid and a different pole section which is a different pole to the liquid spraying section, thereby spraying the liquid from the nozzle toward the different pole section, the electrostatic spraying device comprising: a voltage application means for applying a voltage between the liquid spraying section and the different pole section to generate an electrostatic force that causes the liquid to be separated from the nozzle in a charged state and atomized; an equipotential line adjustment electrode formed of a conductive material and which adjusts the state of equipotential curves that appear to surround the nozzle when the voltage application means applies a voltage; and an insulating and an electrode cover formed of an insulating material and covering at least the surface on the tip side of the equipotential adjustment electrode, wherein the equipotential adjustment electrode is arranged so that a portion of the electrode cover covering the tip of the equipotential adjustment electrode is located near the outer periphery of the tip of the nozzle and behind the tip of the nozzle, so that the state of the equipotential curve on a plane including the axis of the nozzle which appears near the front side of the nozzle when the equipotential adjustment electrode is not arranged is made to be a state of an equipotential curve which draws a more gentle curve at least a portion of the equipotential curve, and the electrode cover is at the same potential as the liquid spray portion. (2) In the above (1), the equipotential line adjustment electrode has a hole extending from an opening on the tip side toward the rear side, the nozzle is inserted inside the hole with the axis aligned in the fore-and-aft direction, and a gap perpendicular to the axis of the nozzle is formed between at least the inner surface of the hole on the tip side and the outer surface of the nozzle. (3) In the above (2), the gap formed between at least the inner surface of the tip side of the hole portion of the equipotential line adjustment electrode and the outer peripheral surface of the nozzle is 1 mm or more and 10 mm or less from the outer peripheral surface of the nozzle in a direction perpendicular to the axis of the nozzle. (4) In the above (1) or (2), the electrode cover covers a surface of a portion of the equipotential line adjusting electrode that connects the surface on the tip end side with the surface on the rear end side. (5) In the above (4), the electrode cover covers the surface on the rear end side of the equipotential line adjusting electrode. Effect of the Invention

[0007] According to the present disclosure, it is possible to provide an electrostatic spray device that can suppress the generation of sparks due to discharge between a nozzle and an equipotential line adjusting electrode and a portion of a different polarity such as a workpiece. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view showing the overall configuration of an electrostatic spraying device according to a first embodiment of the present invention. [Diagram 2] 1 is an exploded cross-sectional view showing a liquid spray unit, an equipotential line adjusting electrode, and an electrode cover of a first embodiment according to the present invention. FIG. [Diagram 3] 1A and 1B are partially enlarged cross-sectional views of the tip side of the liquid spraying part of the first embodiment, in which (a) shows the case where the tip surface of the mandrel is located rearward of the tip of the nozzle, and (b) shows the case where the tip surface of the mandrel is located further forward than in (a). [Figure 4] FIG. 4 is a diagram showing the state of equipotential curves when a voltage is applied without providing an equipotential line adjustment electrode in the electrostatic spraying device of the first embodiment. [Diagram 5] FIG. 4 is a diagram showing a state when liquid is sprayed in the electrostatic spraying device of the first embodiment without disposing an equipotential line adjustment electrode. [Figure 6] FIG. 4 is a diagram showing the state of equipotential curves when an equipotential line adjustment electrode is disposed and a voltage is applied in the electrostatic spraying device of the first embodiment. [Figure 7] FIG. 2 is a diagram showing a state when an equipotential line adjustment electrode is arranged in the electrostatic spraying device of the first embodiment and liquid is sprayed. [Figure 8] 6 is a cross-sectional view showing a liquid spray unit, an equipotential line adjusting electrode, and an electrode cover in a modified example of the first embodiment. FIG. [Figure 9] FIG. 9 is a perspective view showing a modified example of the first embodiment in FIG. 8. [Figure 10] FIG. 4 is a cross-sectional view showing the overall configuration of an electrostatic spraying device according to a second embodiment of the present invention. [Figure 11]6 is a cross-sectional view showing a liquid spray unit, an equipotential line adjusting electrode, and an electrode cover according to a second embodiment of the present invention. FIG. [Figure 12] FIG. 1 is a cross-sectional view showing an example of a conventional electrostatic spraying device. [Figure 13] FIG. 13 is a perspective view showing a modified example of the equipotential line adjusting electrode. [Figure 14] FIG. 13 is a perspective view showing a modified example of the equipotential line adjusting electrode. [Figure 15] FIG. 13 is a perspective view showing a modified example of the equipotential line adjusting electrode. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a detailed description of an embodiment of the present invention will be given with reference to the accompanying drawings. Note that the same elements are designated by the same reference numerals throughout the description of the embodiment. Unless otherwise specified, expressions such as "end" and "front" refer to the side of each component, etc. in the direction in which the liquid is sprayed, and expressions such as "rear" and "rear" refer to the side of each component, etc. opposite the direction in which the liquid is sprayed.

[0010] The electrostatic spray device of the present invention is an electrostatic spray device that uses the electrospray method, in which a voltage is applied between a liquid spraying section having a nozzle for spraying liquid and a different pole section that is a different pole to the liquid spraying section, thereby spraying liquid from the nozzle toward the different pole section.

[0011] (First embodiment) FIG. 1 is a cross-sectional view showing the overall configuration of an electrostatic spraying device 10 according to a first embodiment of the present invention. As shown in FIG. 1, the electrostatic spraying device 10 is configured to spray liquid from the nozzle 22 toward the opposite pole part 40 by applying a voltage between the liquid spraying part 20 having the nozzle 22 for spraying liquid and the opposite pole part 40 having the opposite pole to the liquid spraying part 20. That is, in the electrostatic spraying device 10, the liquid spraying part 20 is arranged so that the axis line (virtual line) LN of the nozzle 22 extends in the front-rear direction. In this embodiment, the electrostatic spraying device 10 includes the liquid spraying part 20, an equipotential line adjustment electrode 30, a voltage application means (voltage power source) 50, and an electrode cover 120. The electrostatic spraying device 10 is configured so that a voltage can be applied between the liquid spraying part 20 and the opposite pole part 40 by the voltage application means 50. The electrode cover 120 includes an electrode cover body 100 that is a member that covers the surface of the equipotential line adjustment electrode 30.

[0012] (liquid spray section) FIG. 2 is an exploded cross-sectional view of the liquid spray unit 20, the equipotential line adjusting electrode 30, and the electrode cover 120. As shown in FIG. As shown in Fig. 2, the liquid spraying part 20 includes a body part 21 made of an insulating material, a nozzle 22 arranged at the tip of the body part 21 and made of a conductive material, and a core 23 made of a conductive material. A liquid flow path 21b through which the liquid flows is formed in the body part 21. The liquid flow path 21b has a liquid supply port 21a that can supply the liquid to the liquid flow path 21b. The nozzle 22 includes an internal space that communicates with the liquid flow path 21b of the body part 21, and is configured to be able to flow the liquid through the internal space. The core 23 is arranged from inside the liquid flow path 21b of the body part 21 to inside the internal space of the nozzle 22.

[0013] A hole 21c communicating with the liquid flow path 21b is provided in the body 21 to allow the stem 23 to be removed from the rear end side. A seal member 24 is provided in the hole 21c to seal the gap between the stem 23 and the hole 21c to prevent liquid from leaking. In this embodiment, an O-ring is used as the seal member 24, but the seal member is not limited to an O-ring and may be any member capable of sealing.

[0014] A knob 23a made of an insulating material is provided at the rear end of the stem 23, which is located at the rear end side of the body 21 through the hole 21c. Also, an electrical wiring connection part 23b made of a conductive material is provided at the rear end of the stem 23, and is disposed so as to pass through approximately the center of the knob 23a.

[0015] As shown in FIG. 1, an electric wire from a voltage application means 50 is connected to the electric wire connection portion 23b. 2, the electrical wiring connection part 23b comes into contact with the mandrel 23, thereby electrically connecting the mandrel 23 to the electrical wiring connection part 23b. Also, the nozzle 22 is electrically connected to the mandrel 23 via the liquid, as shown in FIG. 1. Therefore, the nozzle 22 and the mandrel 23 have the same potential.

[0016] A female screw structure 21e for screwing and connecting knob portion 23a is provided on the inner peripheral surface of rear end opening 21d, which is an opening on the rear end side of body portion 21. Meanwhile, a male screw structure 23c is provided on the outer peripheral surface of the tip end of knob portion 23a.

[0017] Therefore, the mandrel 23 is removably attached to the body portion 21 by screwing the male thread structure 23c on the outer circumferential surface of the tip of the knob portion 23a into the female thread structure 21e of the rear end opening 21d of the body portion 21. Furthermore, by adjusting the amount of screwing of knob 23a, spindle 23 moves in the front-rear direction, so that the position of tip surface 23d of spindle 23 can be adjusted in the front-rear direction.

[0018] Generally, in an electrostatic spraying device, a nozzle for spraying liquid is formed so that the diameter of the internal space through which the liquid flows is relatively small, and such internal space is made into a minute liquid flow path. This is presumably because if the opening diameter of the nozzle tip from which the liquid flows out is large, it becomes difficult to obtain a stable atomization state of the liquid. For example, the opening diameter of the nozzle tip is generally set to less than 0.1 mm.

[0019] For this reason, the opening at the tip of the nozzle quickly becomes clogged when the liquid dries, and because the diameter of this opening is small, there is a problem in that it is difficult to unclog the opening.

[0020] However, for reasons that will be explained later, it has been discovered that by using the mandrel 23, good atomization can be achieved even if the opening diameter at the nozzle tip is made larger than in the past. Therefore, in this embodiment, the opening diameter of the opening 22b at the tip of the nozzle 22 can be made relatively large (for example, 0.2 mm). As a result, the frequency with which clogging occurs can be significantly reduced.

[0021] The diameter of the opening 22b of the nozzle 22 is not limited to 0.2 mm, and in a configuration in which the mandrel 23 is used, there is no problem even if the opening diameter is about 1 mm.

[0022] Considering that clogging is unlikely to occur and that cleaning can be performed even if clogging does occur, the opening diameter of the opening 22b of the nozzle 22 is preferably 0.1 mm or more, more preferably 0.2 mm or more, and further preferably greater than 0.2 mm.

[0023] On the other hand, in consideration of the stability of atomization, the opening diameter of the opening 22b of the nozzle 22 is preferably 1.0 mm or less, more preferably 0.8 mm or less, and even more preferably 0.5 mm or less.

[0024] Furthermore, in this embodiment, as described above, the axle 23 can be moved in the front-rear direction, so that even if clogging occurs, the clogging can be eliminated by moving the axle 23. Furthermore, since the inner diameter of the internal space of the nozzle 22 is made relatively large enough to accommodate the mandrel 23, the mandrel 23 can be removed and washed with a large amount of washing liquid.

[0025] Figure 3 is an enlarged view of the tip side of the liquid spraying section 20, where Figure 3(a) shows the case where the tip surface 23d of the mandrel 23 is located rearward of the tip of the nozzle 22, and Figure 3(b) shows the case where the tip surface 23d of the mandrel 23 is located further forward than in the state of Figure 3(a).

[0026] 3(a), the nozzle 22 has a tapered inner diameter portion (see range A) whose inner diameter tapers toward the opening 22b at a taper angle α, and the mandrel 23 has a tapered portion (see range B) whose outer diameter tapers toward the tip surface 23d at a taper angle β.

[0027] The taper angle α of the tapered inner diameter portion of the nozzle 22 is larger than the taper angle β of the tapered portion of the mandrel 23 . The diameter of the tip surface 23d of the mandrel 23 is smaller than the opening diameter of the opening 22b of the nozzle 22. On the other hand, the diameter of the tapered portion of the mandrel 23 gradually increases toward the rear end. The tapered portion of the mandrel 23 is formed to have a portion with a larger diameter than the opening diameter of the opening 22b of the nozzle 22.

[0028] 3(a) and (b), by forming the tip side of the nozzle 22 and the stem 23 as described above, it becomes possible to adjust the width of the gap formed between the nozzle 22 and the stem 23 by moving the stem 23 back and forth. Therefore, the amount of liquid coming out from the opening 22b of the nozzle 22 can be adjusted.

[0029] 3(b), the mandrel 23 can be brought into contact with the inner circumferential surface of the nozzle 22. This makes it possible for the mandrel 23 to close the opening 22b of the nozzle 22. Therefore, when the liquid is not being sprayed, the opening 22b of the nozzle 22 is blocked by the stem 23, and the liquid in the nozzle 22 can be prevented from drying out. Therefore, clogging of the nozzle 22 can be suppressed.

[0030] (Equipotential adjustment electrode) As shown in FIG. 2, the equipotential line adjusting electrode 30 has a screw hole 31a provided with a female screw structure. After the equipotential line adjustment electrode 30 is mounted on the nozzle 22 of the liquid spray section 20, the equipotential line adjustment electrode 30 is fixed to the nozzle 22 by screwing a fixing screw 31 into the screw hole 31a of the equipotential line adjustment electrode 30 and tightening the fixing screw 31 so that the fixing screw 31 presses against the outer periphery of the nozzle 22.

[0031] In this manner, the equipotential line adjusting electrode 30 is attached so as to be disposed in the vicinity of the outer periphery of the tip of the nozzle 22 of the liquid spraying section 20, as shown in FIG. More specifically, in this embodiment, the equipotential line adjusting electrode 30 is fixed to the outer periphery of the nozzle 22 so as to be disposed rearward of the tip outer periphery 22a of the nozzle 22, as shown in FIG.

[0032] As described above, the equipotential line adjustment electrode 30 is fixed to the nozzle 22 by the fixing screw 31, and therefore can be moved along the nozzle 22 by loosening the fixing screw 31. This allows the equipotential line adjustment electrode 30 to be adjusted in its position in the front-rear direction along the nozzle 22.

[0033] In this embodiment, the equipotential line adjustment electrode 30 is fixed to the nozzle 22, but it is sufficient that the equipotential line adjustment electrode 30 is disposed near the outer periphery of the tip of the nozzle 22. For example, the equipotential line adjustment electrode 30 may be fixed to the body part 21 of the liquid spray part 20 using an arm structure or the like.

[0034] The equipotential line adjustment electrode 30 is made of a conductive material. As shown in FIG. 1, an electric wiring branched from an electric wiring connected from the voltage application means 50 to the electric wiring connection part 23b is connected to the equipotential line adjustment electrode 30. Therefore, the equipotential line adjustment electrode 30 has the same potential as the liquid spray part 20 (the stem 23 in this example). As described above, the nozzle 22 has the same potential as the stem 23. Therefore, the equipotential line adjustment electrode 30 has the same potential as the nozzle 22.

[0035] (Different polarity part 40) In this embodiment, a coating object is used as the opposite electrode part 40. The electrical wiring on the opposite side to the mandrel 23 is connected to the coating object, and the coating object itself becomes the opposite electrode with respect to the liquid spray part 20. Moreover, the workpiece to be coated, which becomes the different polarity portion 40, is earthed by earthing means 80. This earthing means 80 is not an essential requirement, but it is preferable to provide it from the viewpoint of safety since there is a possibility that an operator may come into contact with the object to be coated.

[0036] In this embodiment, electrical wiring is connected to the object to be coated from the voltage application means 50 in order to make the object to be coated the opposite polarity part 40. However, in order to make the object to be coated the opposite polarity part 40, it is not necessary to directly connect electrical wiring to the object to be coated.

[0037] For example, in cases where the workpiece is transported by a conveying device or the like to a position where a liquid such as paint is to be applied, electrical wiring from the voltage application means 50 may be connected to a mounting section of the conveying device on which the workpiece is placed, so that the workpiece is electrically connected to the voltage application means 50 via the mounting section.

[0038] Next, the state in which a liquid is sprayed using the electrostatic spraying device 10 of the first embodiment having the above-mentioned configuration will be described, and the configuration of the electrostatic spraying device 10 of the first embodiment will be further described in detail. FIG. 4 is a side view showing only the tip side of the nozzle 22 without the equipotential line adjusting electrode 30 disposed thereon. FIG. 5 is a diagram showing a state when the equipotential line adjusting electrode 30 is not arranged and liquid is sprayed from the liquid spraying part 20. As shown in FIG. 4 and 5 are reference diagrams for explaining the action of the equipotential line adjustment electrode 30. In addition, Fig. 4 and Fig. 5 are diagrams showing a state in which the equipotential line adjustment electrode 30 is not arranged, for comparison with the electrostatic spraying device 10 of the first embodiment.

[0039] In Fig. 4, the axis LN of the nozzle 22 is shown as the Z axis, and one axis perpendicular to this Z axis is shown as the X axis. Also shown is the state of equipotential curves 58 that appear on a cross section in the X-axis direction along this Z axis when a voltage is applied. In other words, Fig. 4 is a diagram showing the state of the equipotential curves 58 on a plane including the axis LN of the nozzle 22.

[0040] As shown in Fig. 4, when a voltage is applied, equipotential curves 58 appear surrounding the nozzle 22. Then, the liquid coming out of the nozzle 22 is pulled by electrostatic force in a direction perpendicular to the tangent of the equipotential curves 58. At this time, the electrostatic force pulling the liquid is balanced against the adhesive force due to the surface tension and viscosity on the tip surface 23d of the stem 23 and the tip outer periphery 22a of the nozzle 22. In this way, the liquid supplied to the tip side of the nozzle 22 becomes in the form of a Taylor cone 60, which has a conical shape at its tip, as shown in Fig. 5.

[0041] This Taylor cone 60 is formed when the action of an electric field causes separation of positive and negative charges in the liquid, causing the meniscus at the tip of the nozzle 22, which is charged with excess electric charge, to deform into a cone shape. The liquid is then pulled straight from the tip of the Taylor cone 60 by electrostatic force and then explodes electrostatically.

[0042] The pulling force toward the front side before the electrostatic explosion becomes the inertial force of the liquid being sprayed. Furthermore, as a result of the interaction of the spreading force (repulsive force) during the electrostatic explosion and the pulling force due to the electrostatic force from the direction perpendicular to the tangent of the equipotential curve 58, the liquid is sprayed toward the front side.

[0043] The sprayed liquid, that is, the liquid that has left the nozzle 22 in a charged state and become liquid particles, has a dramatically larger surface area exposed to the air compared to the state before it left the nozzle 22, accelerating the evaporation of the solvent. As the solvent evaporates, the distance between the charged electrons decreases, causing electrostatic repulsion (electrostatic explosion) and splitting the liquid into smaller liquid particles. When this splitting occurs, the surface area exposed to the air further increases compared to before it split, accelerating the evaporation of the solvent. Then, an electrostatic explosion occurs again, splitting the liquid into smaller liquid particles. Such electrostatic explosions are repeated, and the liquid is atomized.

[0044] The liquid supply to the liquid spraying part 20 only needs to be successively supplied to replace the liquid lost from the liquid spraying part 20 due to consumption by spraying. That is, the liquid supplied to the liquid spraying part 20 does not need to be pumped and supplied with a pressure that causes the liquid to be sprayed from the opening 22b of the nozzle 22 (more precisely, the gap between the opening 22b and the stem 23). If the liquid is forcefully sprayed by such a pumped supply, it may not be possible to atomize the liquid satisfactorily.

[0045] Here, in this embodiment, a mandrel 23 is disposed within the nozzle 22 . If the core 23 were not provided as in a conventional electrostatic spraying device, the only part to which the liquid could adhere would be the outer circumferential edge 22a at the tip of the nozzle 22.

[0046] In this state, if the opening diameter of the opening 22b of the nozzle 22 is increased, for example, the liquid is likely to sway up, down, left, and right of the nozzle 22, making it impossible to form a Taylor cone 60 with a good shape, and the Taylor cone 60 itself cannot be maintained. This makes it impossible to obtain stability in the liquid particles detached from the nozzle 22 (stability in the size, number, and charge state of the particles). As a result, it is presumed that stable atomization of the liquid cannot be achieved.

[0047] On the other hand, in this embodiment, the mandrel 23 is disposed inside the nozzle 22, so that the liquid adheres not only to the outer circumferential edge 22a at the tip of the nozzle 22 but also to the tip surface 23d of the mandrel 23. That is, even if the opening diameter of the opening 22b of the nozzle 22 is formed relatively large, the tip surface 23d of the mandrel 23 to which the liquid can adhere exists in the center of the opening 22b. Therefore, it is believed that a stable Taylor cone 60 can be formed, and stable atomization of the liquid can be achieved.

[0048] If the tip surface 23d of the stem 23 protrudes too far forward from the tip outer circumferential edge 22a of the nozzle 22 (i.e., the tip surface of the opening 22b of the nozzle 22), it becomes difficult for the electric field to act on the liquid coming out of the nozzle 22. On the other hand, if the tip surface 23d of the stem 23 recedes too far rearward from the tip surface of the opening 22b of the nozzle 22, it will be the same as if there is no part in the center of the opening 22b where the liquid can adhere.

[0049] For this reason, when the liquid is sprayed, the position of the tip surface 23d of the core 23, based on the tip surface of the opening 22b of the nozzle 22, in the front-to-back direction along the longitudinal direction of the core 23, is preferably located within 10 times the opening diameter of the opening 22b at the tip of the nozzle 22, more preferably within 5 times, and even more preferably within 3 times.

[0050] For example, in this embodiment, if the opening diameter of opening 22b of nozzle 22 is 0.2 mm and electrostatic force is not taken into consideration, the liquid coming out of opening 22b of nozzle 22 will come out at the tip of nozzle 22 in a hemispherical shape with a diameter of approximately 0.2 mm.

[0051] The tip of the mandrel 23 should be located near the liquid so that an electric field (electrostatic force) acts on the liquid coming out of the tip of the nozzle 22 to form a conical Taylor cone 60. For this reason, the tip of the mandrel 23 is preferably located within 2 mm forward (in the outgoing direction) from the tip surface of the opening 22b of the nozzle 22. On the other hand, the tip of the mandrel 23 is preferably located within 2 mm backward (in the retracting direction) from the tip surface of the opening 22b of the nozzle 22 so as to affect the adhesion of the liquid.

[0052] As described above, by providing the core rod 23, stable atomization of the liquid can be achieved even if the opening diameter of the opening 22b of the nozzle 22 is formed to be relatively large. Therefore, the opening diameter of the opening 22b of the nozzle 22 can be made large enough to prevent clogging. Furthermore, since the opening diameter of the opening 22b of the nozzle 22 can be made large, the nozzle 22 can be manufactured by machining.

[0053] In this embodiment, the tip of the mandrel 23 has a flat surface as the tip surface 23d, but the present invention is not limited to this and may have any surface that contributes to the formation of a stable Taylor cone 60. For example, the tip of the mandrel 23 may have a curved surface that protrudes forward, such as an R-shape.

[0054] Incidentally, as can be seen from FIG. 4, equipotential curves 58 that appear to surround the nozzle 22 when a voltage is applied appear to form a circle with the nozzle 22 at the center. Considering that the pulling force of electrostatic force acts in a direction perpendicular to a tangent line drawn to this equipotential curve 58, the direction perpendicular to the tangent line of the equipotential curve 58 based on the detached liquid can be not only forward but also various other directions such as diagonal and lateral directions. For this reason, the liquid detached from the nozzle 22 is pulled by electrostatic force from various directions, and is sprayed over a wide area in front of the nozzle 22 due to the balance between this electrostatic force, inertial force, electrostatic explosive force (repulsive force), etc.

[0055] Therefore, in this embodiment, an equipotential line adjustment electrode 30 is provided to adjust the state of the equipotential curve 58 to match the spreading state of the liquid according to the application of the liquid. This equipotential line adjustment electrode 30 is made of a conductive material and is set to the same potential as the liquid spray part 20 (the stem 23 in this example).

[0056] Fig. 6 is a side view showing only the tip side of the nozzle 22 that sprays the liquid, similar to Fig. 4, but further shows an equipotential line adjustment electrode 30 and the state of the equipotential curves 58 in that state. The electrode cover 120 is omitted in Fig. 6. The Z-axis and X-axis in FIG. 6 are the same as those shown in FIG. That is, FIG. 6 also shows equipotential curves 58 on a plane including the axis LN of the nozzle 22. FIG. 7 is a diagram showing a state when the equipotential line adjustment electrode 30 is disposed in the electrostatic spraying device 10 and liquid is sprayed.

[0057] As can be seen from Fig. 6, by providing the equipotential line adjustment electrode 30, the equipotential curves 58 are curved more gently than the equipotential curves 58 on a plane including the axis LN of the nozzle 22 that appear near the front side of the nozzle 22 when the equipotential line adjustment electrode 30 is not provided as shown in Fig. 4. It can also be seen that the equipotential curves 58 approach a state in which they are aligned in parallel toward the front side. In other words, by providing the equipotential line adjustment electrode 30, the state of the equipotential curves 58 when the equipotential line adjustment electrode 30 is not provided is changed to a state in which at least a part of the equipotential curves 58 are curved more gently.

[0058] 7, the equipotential line adjustment electrode 30 is disposed so that the tip 30a of the equipotential line adjustment electrode 30 is located near the outer periphery of the tip of the nozzle 22, which can be made into the state of a gently curving equipotential curve 58, and behind the tip of the nozzle 22. The electrode cover 120 is disposed so that the tip cover part 100a, which is the part of the electrode cover body 100 that covers the tip part 30a of the equipotential line adjustment electrode 30, is located near the outer periphery of the tip of the nozzle 22 and behind the tip of the nozzle 22.

[0059] In addition, the vicinity of the front side of the nozzle 22 means a range within 150 mm, more specifically within 100 mm, in a direction perpendicular to the axis LN of the nozzle 22 based on the axis LN of the nozzle 22, and does not exceed a cylindrical range forward from the tip of the nozzle 22, within 150 mm, more specifically within 100 mm, in front of the nozzle 22.

[0060] 6, the direction perpendicular to the tangent of the equipotential curve 58 with respect to the detached liquid is mainly forward. Therefore, although the liquid spreads due to electrostatic explosion during and after the detachment, it spreads less easily compared to the state where the equipotential line adjustment electrode 30 is not provided. As a result, as shown in FIG. 7, the sprayed liquid is sprayed without spreading too much.

[0061] If the equipotential line adjustment electrode 30 is disposed too far back from the nozzle 22, the effect of adjusting the equipotential curve 58 decreases. For this reason, the equipotential line adjustment electrode 30 needs to be disposed in the vicinity of the outer periphery of the tip of the nozzle 22. In other words, it is a position where the equipotential line 58 can be made to have a more gentle curve than the equipotential curve 58 that appears on the front side of the nozzle 22 when the equipotential line adjustment electrode 30 is not disposed.

[0062] 2 and other figures, in this embodiment, the tip 30a of the equipotential line adjustment electrode 30 is configured as a flat surface. By doing so, as shown in FIG. 6, the equipotential curve 58 appearing between the tip 30a of the equipotential line adjustment electrode 30 and the nozzle 22 is prevented from curving rearward beyond the tip 30a of the equipotential line adjustment electrode 30.

[0063] For example, if the flat portion of the tip 30a of this equipotential line adjustment electrode 30 is eliminated and made into a cylindrical equipotential line adjustment electrode that opens forward, it is thought that the equipotential curve 58 would be more likely to have a recess toward the rear near the nozzle 22.

[0064] If this happens, a sudden change in the equipotential curve 58 will occur in the vicinity of the nozzle 22. For this reason, although it is thought that this will depend on the position of the detachment point where the liquid electrostatically explodes and detaches, there is a possibility that the effect of suppressing the spread of the liquid will become unstable.

[0065] For this reason, it is considered more preferable to prevent the equipotential curve 58 appearing between the tip 30a of the equipotential adjustment electrode 30 and the nozzle 22 from curving rearward beyond the tip 30a of the equipotential adjustment electrode 30, as in this embodiment.

[0066] (Electrode cover) As shown in FIG. 1, the electrode cover body 100 provided in the electrode cover 120 covers at least the surface of the tip 30a side of the equipotential line adjustment electrode 30 in a state in which the equipotential line adjustment electrode 30 is attached to the nozzle 22. The electrode cover body 100 has a tip cover part 100a that covers the surface of the tip 30a side of the equipotential line adjustment electrode 30, and a side cover part 100b that covers the side part 30b of the equipotential line adjustment electrode 30. As shown in FIG. 2, the electrode cover body 100 has a nozzle hole part 100c in the tip cover part 100a. The nozzle 22 is inserted into the nozzle hole part 100c. As shown in FIG. 1, the tip of the nozzle 22 protrudes from the nozzle hole part 100c. The electrode cover body 100 is formed of an insulating material. The insulating material forming the electrode cover body 100 may be, for example, resin, rubber, glass, or the like.

[0067] FIG. 12 is a cross-sectional view showing an example of a conventional electrostatic spraying device 510. As shown in FIG. 12, in an electrostatic spraying device 510, a cover covering the surface of the equipotential line adjusting electrode 30 corresponding to the electrode cover 120 shown in FIG. 1 is not provided.

[0068] In Fig. 12, a different electrode body 90 is disposed near the tip of the nozzle 22 of a conventional liquid spray section 520 and the equipotential line adjustment electrode 30. The different electrode body 90 is, for example, the wall of a coating booth or various equipment and fixtures. This different electrode body 90 is earthed by earthing means 80 and has the same potential as the workpiece, which is the different electrode part 40. Therefore, a voltage is applied by voltage application means 50 between the tip of the nozzle 22 and the equipotential line adjustment electrode 30 and the workpiece 40 and the different electrode body 90.

[0069] Depending on the relationship between the voltage applied by the voltage application means 50 and the distance between the tip of the nozzle 22 and the equipotential line adjustment electrode 30 and the workpiece 40 and the opposite electrode body 90, or the relationship between the tip of the nozzle 22 and the equipotential line adjustment electrode 30 and the amount of charge accumulated in the tip of the nozzle 22 and the equipotential line adjustment electrode 30, there is a risk of sparks being generated by discharge between the nozzle 22 and the equipotential line adjustment electrode 30 and the workpiece 40 and the opposite electrode body 90. In other words, if the spraying operation is performed correctly and the distance between the tip of the nozzle 22 and the equipotential line adjustment electrode 30 and the workpiece 40 and the opposite electrode body 90 is maintained at a predetermined distance or more, there is no problem even with the conventional electrostatic spraying device 510. However, if the distance between the tip of the nozzle 22 and the equipotential line adjustment electrode 30 and the workpiece 40 and the opposite electrode body 90 is mistakenly brought too close to within the predetermined distance during the spraying operation, there is a risk of sparks being generated by discharge between the nozzle 22 and the equipotential line adjustment electrode 30 and the workpiece 40 and the opposite electrode body 90 in the conventional liquid spraying section 520.

[0070] As shown in Fig. 1, the electrostatic spraying device 10 of the first embodiment according to the present invention has an electrode cover 120. The electrode cover 120 has an electrode cover body 100 made of an insulating material that covers at least the surface of the tip 30a side of the equipotential line adjustment electrode 30 arranged in the vicinity of the outer periphery of the tip of the nozzle 22 of the liquid spraying part 20. In this way, it is possible to prevent or suppress the generation of sparks due to discharge between the equipotential line adjustment electrode 30 and the opposite pole part 40 (subject to be coated) and the opposite pole body 90 on the tip 30a side of the equipotential line adjustment electrode 30.

[0071] As shown in FIG. 1 and FIG. 2, the electrode cover body 100 provided in the electrode cover 120 is provided so that the tip cover part 100a covers the tip side of the equipotential line adjustment electrode 30, i.e., the surface of the tip part 30a side. Furthermore, the side cover part 100b may cover the side part 30b of the equipotential line adjustment electrode 30. That is, the electrode cover 120 may cover the surface of the side part 30b which is the part connecting the surface of the tip part 30a side of the equipotential line adjustment electrode 30 and the surface of the rear end part 30c side of the rear side of the nozzle 22. By doing so, even if the workpiece 40 or the opposite electrode body 90 approaches the vicinity of the side part 30b of the equipotential line adjustment electrode 30, it is possible to prevent or suppress the generation of sparks due to discharge between the equipotential line adjustment electrode 30 and the workpiece 40 and the opposite electrode body 90. Note that, as shown in FIG. 1, the side cover part 100b is provided so as to cover the entire area of ​​the side part 30b of the equipotential line adjustment electrode 30, but is not limited thereto. Depending on the situation in which the electrostatic spraying device 10 is used, the side cover portion 100b may cover, for example, from the tip end 30a side of the side portion 30b toward the rear side up to near the center.

[0072] The electrode cover 120 shown in Figs. 1 and 2 is attached by fitting the inner periphery 100d of the electrode cover body 100 into the side portion 30b of the equipotential line adjusting electrode 30, but the attachment method is not limited to this.

[0073] FIG. 8 is a cross-sectional view showing the liquid spray part 20, the equipotential line adjusting electrode 30, and the electrode cover 120 in a modified example of the first embodiment. FIG. 9 is a perspective view showing a modification of the first embodiment of FIG. Modifications of the electrode cover 120 will be described with reference to FIGS.

[0074] As shown in FIG. 8, the electrode cover 120 includes an electrode cover body 100 and an electrode cover body 110. That is, the electrode cover 120 shown in FIG. 8 includes the electrode cover body 100 shown in FIG. 1 and FIG. 2, and further includes an electrode cover body 110 that covers the surface of the rear end portion 30c side, which is the rear side of the equipotential line adjustment electrode 30. The electrode cover body 110 is formed of an insulating material. In this way, the electrode cover 120 may include the electrode cover body 100, which is the first electrode cover body, and the electrode cover body 110, which is the second electrode cover body. And, as shown in FIG. 8, the electrode cover body 110 is attached by fitting the inner periphery of the side cover part 110b into the outer periphery of the side cover part 100b of the electrode cover body 100. However, the attachment method is not limited to this. In this way, the electrode cover 120 may include one or more electrode cover bodies, which are members that cover the surface of the equipotential line adjustment electrode 30. 8, the electrode cover 120 may include two electrode cover bodies, or may include three or more electrode cover bodies, such as a third electrode cover body. In this way, the electrode cover 120 can more appropriately cover the surfaces of the equipotential line adjusting electrodes 30 of various shapes.

[0075] The electrode cover body 110 has a rear cover part 110a that covers the surface of the equipotential line adjustment electrode 30 on the rear end 30c side. As shown in Fig. 8 and Fig. 9, the electrode cover 120 covers the equipotential line adjustment electrode 30 from the front and rear with the electrode cover body 100 and the electrode cover body 110. That is, the electrode cover 120 covers almost the entire surface of the equipotential line adjustment electrode 30 with the electrode cover body 100 and the electrode cover body 110 formed of an insulating material. That is, the electrode cover 120 covers the surface of the equipotential line adjustment electrode 30 on the front end 30a side with the front end cover part 100a of the electrode cover body 100, covers the side part 30b of the equipotential line adjustment electrode 30 with the side cover part 100b, and further covers the surface of the equipotential line adjustment electrode 30 on the rear end 30c side with the rear cover part 110a of the electrode cover body 110. In this way, the electrode cover 120, by using the electrode cover body 100 and the electrode cover body 110, covers not only the surface on the tip side of the equipotential line adjusting electrode 30, but also the surface of the equipotential line adjusting electrode 30 other than the tip side.

[0076] By doing this, it is possible to prevent or suppress the generation of sparks due to discharge between the nozzle 22 and equipotential line adjustment electrode 30 and the workpiece 40 and the opposite electrode body 90, regardless of whether the workpiece 40 or the opposite electrode body 90 is located at the tip, rear, or side of the nozzle 22.

[0077] Second embodiment FIG. 10 is a cross-sectional view showing the overall configuration of an electrostatic spraying device 10 according to a second embodiment of the present invention. FIG. 11 is a cross-sectional view showing the liquid spray unit 20, the equipotential line adjusting electrode 230, and the electrode cover 220 of the second embodiment according to the present invention. An electrostatic spraying device 10 according to a second embodiment will be described with reference to Figs.

[0078] The electrostatic spraying device 10 of the second embodiment differs from the first embodiment in that it is provided with an equipotential line adjustment electrode 230 having a hole 230d on the tip side of the nozzle 22, but otherwise has the same configuration as the electrostatic spraying device 10 of the first embodiment. In the following, we will mainly explain these differences and may not repeat the explanation of similar points.

[0079] As shown in Figs. 10 and 11, the equipotential line adjustment electrode 230 has a hole 230d. This hole 230d is provided from an opening provided on the tip end 230a side, which is the tip side of the equipotential line adjustment electrode 230, toward the rear side, i.e., toward the rear end 230c side. The hole 230d of the equipotential line adjustment electrode 230 is provided so that the axis LN of the nozzle 22 passes through it. The nozzle 22 is inserted inside the hole 230d in a state in which the axis LN of the nozzle 22 is arranged in the front-rear direction. A gap P is formed between at least the inner peripheral surface of the tip side of the hole 230d and the outer peripheral surface of the nozzle 22 in the radial direction of the nozzle 22, i.e., in the direction perpendicular to the axis LN of the nozzle 22.

[0080] As shown in Fig. 10 and Fig. 11, the electrode cover 220 includes an electrode cover body 200 and an electrode cover body 210. The equipotential line adjustment electrode 230 is shown to cover the surface of the tip portion 230a side of the equipotential line adjustment electrode 30, which is the surface other than the tip portion side, that is, the side portion 230b and the surface of the rear end portion 230c side, by the electrode cover body 200 which is the first electrode cover body and the electrode cover body 210 which is the second electrode cover body. However, this is not limited to this. For example, the electrode cover 220 may include only the electrode cover body 200 and cover only the surface of the tip portion 230a side, or may cover the surface of the tip portion 230a side and the surface of the side portion 230b which is the surface other than the tip portion 230a side. As shown in FIG. 11, the electrode cover body 210 is attached by fitting the inner periphery of the side cover portion 210b into the outer periphery of the side cover portion 200b of the electrode cover body 200, but the attachment method is not limited to this.

[0081] As shown in Figs. 10 and 11, the electrode cover 220 is configured to cover substantially the entire surface of the equipotential line adjustment electrode 230 with the electrode cover body 200 and the electrode cover body 210 formed of an insulating material. Even in this case, the tip of the nozzle 22 is not covered with the electrode cover body 200 and the electrode cover body 210. Therefore, the liquid can be sprayed from the tip of the nozzle 22. The equipotential line adjustment electrode 230 is arranged so that the tip portion 230a of the equipotential line adjustment electrode 230 is located behind the tip of the nozzle 22. The electrode cover 220 is also arranged so that the tip cover portion 200a, which is a portion of the electrode cover body 200 that covers the tip portion 30a of the equipotential line adjustment electrode 30, is located behind the tip of the nozzle 22. Therefore, as shown in Fig. 11, the tip of the nozzle 22 protrudes forward from the tip cover portion 200a of the electrode cover body 200.

[0082] Therefore, depending on the voltage applied by the voltage application means 50, or the distance between the tip of the nozzle 22 and the workpiece 40 and the opposite electrode body 90, there is a risk of sparks being generated due to discharge between the tip of the nozzle 22 and the workpiece 40 and the opposite electrode body 90 located on the tip side of the nozzle 22.

[0083] By providing a hole 230d in the equipotential line adjustment electrode 230 and forming a gap P between the inner surface of this hole 230d and the outer surface of the nozzle 22 in a direction perpendicular to the axis LN of the nozzle 22, it is possible to prevent or suppress the generation of sparks due to discharge between the tip of such a nozzle 22 and the opposite pole portion 40 (workpiece to be coated) and the opposite pole body 90 on the tip side of the nozzle 22.

[0084] In other words, by providing the hole 230d in the equipotential line adjustment electrode 230, the charge accumulated in the electrode cover body 200 of the electrode cover 220 is prevented from moving to the nozzle 22, and the occurrence of sparks due to discharge (so-called creeping discharge) between the tip of the nozzle 22 and the opposite electrode portion 40 (substrate to be coated) and the opposite electrode body 90 on the tip side of the nozzle 22 can be prevented or suppressed.

[0085] The gap P between the inner peripheral surface of the hole 230d provided in the equipotential line adjusting electrode 230 and the outer peripheral surface of the nozzle 22 is preferably large from the viewpoint of preventing the charge accumulated in the electrode cover body 200 of the electrode cover 220 from moving to the nozzle 22. However, if the hole 230d is too large, there is a risk that the function of the equipotential line adjusting electrode 230 in adjusting the state of the equipotential curve 58 that appears to surround the nozzle 22 will be reduced.

[0086] From this viewpoint, it is desirable that the gap P formed between at least the inner surface of the tip side of the hole portion 230d in the equipotential line adjustment electrode 230 and the outer surface of the nozzle 22 be 1 mm or more and 10 mm or less from the outer surface of the nozzle 22 in a direction perpendicular to the axis LN of the nozzle 22.

[0087] The gap P between the inner peripheral surface of the hole 230d of the equipotential line adjustment electrode 230 and the outer peripheral surface of the nozzle 22 may be provided over the entire circumference of the inner peripheral surface of the hole 230d and the outer peripheral surface of the nozzle 22, but is not limited to this. In other words, the gap P between the inner peripheral surface of the hole 230d of the equipotential line adjustment electrode 230 and the outer peripheral surface of the nozzle 22 may be provided over the entire circumference between the inner peripheral surface of the hole 230d and the outer peripheral surface of the nozzle 22, or may be provided between a part of the inner peripheral surface of the hole 230d in the circumferential direction and a part of the outer peripheral surface of the nozzle 22 in the circumferential direction.

[0088] 10 and 11, the hole 230d is shown as having an opening only at the tip 230a of the equipotential adjustment electrode 230 and having a bottom on the rear side, but this is not limited thereto. That is, the hole 230d may have an opening not only at the tip 230a of the equipotential adjustment electrode 230 but also at the rear end 230c on the rear side, and the hole 230d may penetrate the equipotential adjustment electrode 230. In this case, the equipotential adjustment electrode 230 is not limited to being fixed to the nozzle 22, and may be fixed to the body 21 of the liquid spraying part 20, for example, or may be fixed by an arm structure or the like. That is, regardless of the fixing method, it is sufficient that the equipotential adjustment electrode 230 is arranged near the outer periphery of the tip of the nozzle 22.

[0089] The tip cover part 200a of the electrode cover body 200 is provided with a nozzle hole 200c penetrating the tip cover part 200a. The tip of the nozzle 22 protrudes from the nozzle hole 200c. A gap may be formed between the inner peripheral surface of the nozzle hole 200c and the outer peripheral surface of the nozzle 22 in a direction perpendicular to the axis LN of the nozzle 22.

[0090] As shown in FIG. 11, in the electrode cover 220, the nozzle hole 200c of the electrode cover body 200 is provided so as to extend toward the rear of the nozzle 22 along the inner circumferential surface of the hole 230d of the equipotential line adjustment electrode 230. The nozzle hole 200c is formed from the front surface of the tip cover part 200a of the electrode cover body 200 toward the rear to the middle of the equipotential line adjustment electrode 230. The electrode cover body 200 has a tubular part that extends in a tubular shape from the rear surface of the tip cover part 200a toward the rear. The hole of this tubular part forms a part of the nozzle hole 200c. The part of the electrode cover body 200 inserted into the hole 230d of the equipotential line adjustment electrode 230 (the tubular part in this embodiment) covers the inner surface of the hole 230d (the inner circumferential surface of the hole 230d in this embodiment). However, the electrode cover body 200 is not limited to having this tubular portion.

[0091] A gap is formed between the inner peripheral surface of the nozzle hole 200c of the electrode cover body 200 and the outer peripheral surface of the nozzle 22 in a direction perpendicular to the axis LN of the nozzle 22. Similarly, in the first embodiment, a gap may be formed between the inner peripheral surface of the nozzle hole 100c of the electrode cover body 100 and the outer peripheral surface of the nozzle 22 in a direction perpendicular to the axis LN of the nozzle 22. This gap may be provided over the entire circumference of the inner peripheral surface of the nozzle hole 100c and the outer peripheral surface of the nozzle 22, but is not limited to this. By providing this gap, it is possible to prevent or suppress the generation of sparks due to discharge (so-called creeping discharge) between the tip of the nozzle 22 and the opposite electrode part (coated object) 40 and the opposite electrode body 90 on the tip side of the nozzle 22, along the surface of the electrode cover body 100 made of an insulating material.

[0092] Although the present invention has been described above based on specific embodiments, the present invention is not limited to the above embodiments, and modifications and improvements may be made as appropriate.

[0093] For example, the surface of a modified example of the equipotential line adjusting electrode 30 shown in Figures 13, 14, and 15, or an example of these with a hole similar to the hole 230d, may be covered with an electrode cover 120 made of an insulating material or an equivalent to the electrode cover 220.

[0094] The equipotential line adjusting electrode 30 shown in FIG. 13 is formed in a shape that is inclined rearward from the nozzle 22 side toward the outside. 14, the width of the plane of the tip 30a in the Y-axis direction is narrower than the width of the plane of the tip 30a in the X-axis direction. This equipotential line adjustment electrode 30 can make the liquid spray pattern elliptical. 15 is arranged so that the fan-shaped electrode portion is located above the nozzle 22. This equipotential line adjustment electrode 30 makes the equipotential curve 58 appearing in the vicinity of the front side of the nozzle 22 curve more gently within the range of this fan-shaped electrode portion than in the state before the equipotential line adjustment electrode 30 was arranged.

[0095] In this way, even if the surface of the equipotential line adjustment electrode 30 shown in Figures 13, 14, and 15, or one of these with a hole similar to hole 230d at its tip, is covered with an electrode cover 120 made of an insulating material or with something equivalent to electrode cover 220, it is possible to prevent or suppress the generation of sparks due to discharge between the outer circumferential edge 22a of the tip of the nozzle 22 and the opposite electrode portion (workpiece) 40 and opposite electrode body 90 on the tip side of the nozzle 22.

[0096] As such, the present invention is not limited to the specific embodiments, and appropriate modifications and improvements are also included within the technical scope of the present invention, which will be apparent to those skilled in the art from the description of the claims. [Explanation of symbols]

[0097] 10 Electrostatic spraying device 20 Liquid spray section 21 Body 21a Liquid supply port 21b Liquid flow path 21c hole 21d Rear end opening 22 Nozzle 22a Tip outer edge 22b opening 23 Mandrel 23a Knob 23b Electrical wiring connection 23c male thread structure 23d tip surface 24 Sealing material 30 Equipotential adjustment electrode 30a Tip 30b Side 30c rear end 31 Fixing screw 31a screw hole 40 Different polarity (subject to be coated) 50 Voltage application means 60 Theracorn 70 Electrodes (different poles) 71 Electrode holder 80 Earthing means 90 Heterodera 100 Electrode cover body 100a Tip cover part 100b Side cover part 100c Nozzle hole 100d inner circumference 110 Electrode cover body 110a Rear cover part 110b Side cover part 120 Electrode cover 200 Electrode cover body 200a Tip cover 200b Side cover part 200c Nozzle hole 210 Electrode cover body 210a Rear cover part 210b Side cover part 220 Electrode Cover 230 Equipotential adjustment electrode 230a Tip 230b Side 230c rear end 230d Hole 510 Electrostatic spraying device 520 Liquid spray section

Claims

1. An electrostatic spraying device that sprays a liquid from the nozzle toward the opposite-pole part by applying a voltage between a liquid spraying part having a nozzle for spraying the liquid and an opposite-pole part that is of the opposite pole to the liquid spraying part, an electrode that is disposed near the outer periphery of the tip of the nozzle and has a tip part, and an electrode cover that covers at least the surface of the tip part side of the electrode. The electrostatic spraying device is provided with these components.

2. The electrode has a hole part provided from an opening provided on the tip part side toward the rear side, the nozzle is inserted inside the hole part in a state where the axis thereof is arranged in the front-rear direction, a gap in a direction perpendicular to the axis of the nozzle is formed between at least the inner peripheral surface of the tip part side of the hole part and the outer peripheral surface of the nozzle. The electrostatic spraying device according to Claim 1.

3. The gap formed between at least the inner peripheral surface of the tip part side of the hole part in the electrode and the outer peripheral surface of the nozzle is 1 mm or more and 10 mm or less from the outer peripheral surface of the nozzle in a direction perpendicular to the axis of the nozzle. The electrostatic spraying device according to Claim 2.

4. The electrode cover covers at least the surface of the side part of the electrode. The electrostatic spraying device according to Claim 1.

5. The electrode cover covers at least the surface of the rear end part side of the electrode. The electrostatic spraying device according to Claim 1.

6. The electrode cover has a hole part through which the nozzle is inserted, and the nozzle is arranged so as to protrude from the hole part of the electrode cover. The electrostatic spraying device according to Claim 1.

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