JP2008126105A - Electrostatic sprayer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic sprayer hardly causing a short circuit between a nozzle and an electrode. <P>SOLUTION: A suction orifice 23 for taking in outside air A1 under the negative pressure caused by spraying a liquid from a spray nozzle 9 is provided to a nozzle cover 19. An inward flange 27 for holding the electrode 10 is further provided to the nozzle cover 19 and a plurality of exhaust orifices 29 are provided to the inward flange 27 at the positions the electrode 10 with intervals in a peripheral direction. The air A1 taken in from the suction port 23 flows along the inner surface of the nozzle cover 19 to be discharged in a spray direction. Further, a part A2 of the air taken in from the suction port 23 is also discharged from the exhaust orifices 29. Accordingly, since liquid droplets S hardly adhere to the inside of the nozzle cover 19, especially the inner surface side of the inward flange 27 and released by discharged air streams before accumulated, they are not grown to large liquid droplets. As a result, the voltage drop caused by the short circuit and electric leakage are prevented. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrostatic spraying device for charging spray droplets of a conductive liquid and attaching them efficiently to an object.

  The electrostatic spraying device includes a spray nozzle for spraying a liquid such as agricultural chemicals into fine droplets, and an electrode disposed so as to be close to the outside of the diffusion range of the droplets. It is known that a voltage is applied to a droplet ejected from the spray nozzle by applying a voltage.

  In the electrostatic spray apparatus as described above, spray droplets adhere to the inner surface of the electrode, the spray nozzle, and the nozzle cover that covers the periphery of the spray nozzle. When the adhesion range of droplets to these members increases due to the continuous spraying operation, voltage leakage increases and effective electrostatic application is difficult to be performed. In addition, when the spray nozzle serving as the ground potential portion is electrically connected to the electrode through a continuous film of droplets attached to the inner surface of the nozzle cover, electrostatic application is not performed.

  Therefore, conventionally, in the following Patent Document 1, a creeping distance from the spray nozzle to the electrode is provided by providing a cylindrical portion concentric with the spray nozzle inside the nozzle cover or by providing a flange portion around the spray nozzle. It has been proposed to extend.

In Patent Document 2 below, it has also been proposed to forcibly discharge droplets in the nozzle cover to the outside using the compressed air of the compressor.
JP 2005-324181 A JP 2006-21148 A

  However, even in the case of Patent Document 1, if a spraying operation is continuously performed for a long time, a continuous film of spray droplets is inevitably formed in the nozzle cover.

  Moreover, since the thing of the said patent document 2 requires a compressor and its drive source in performing a spraying operation | work, both a man-hour and cost become large.

  The present invention has been made in view of such circumstances, and is intended to provide an electrostatic spraying device that is unlikely to cause a voltage drop due to a short circuit or leakage between nozzles and electrodes, and that is inexpensive and easy to handle. is there.

  In order to solve the above-described problems, an electrostatic spraying apparatus according to the present invention includes a spray nozzle that diffuses and sprays a liquid into droplets, and an electric charge for the droplets disposed near the outside of the droplet diffusion range. And a nozzle cover that covers the periphery of the spray nozzle and holds the electrode, and the nozzle cover takes in external air at a negative pressure generated by spraying liquid from the spray nozzle. And an inward flange for holding the electrode, and the inward flange has a plurality of exhaust ports formed at positions outside the electrode at intervals in the circumferential direction. (Claim 1).

  According to the present invention, charges are applied to the spray droplets by spraying the liquid from the spray nozzle while applying a high voltage to the electrode. Since negative pressure is generated in the nozzle cover by the liquid jet from the spray nozzle, outside air is sucked into the nozzle cover from the intake port. The taken-in air flows along the inner surface of the nozzle cover and is discharged along with the spray droplets in the spray direction. A part of the air taken in from the intake port is also released from the exhaust port. For this reason, it is difficult for liquid droplets to adhere to the inside of the nozzle cover, in particular, the inner surface side of the inward flange, and even if the liquid droplets adhere, they are separated by the discharge airflow before being accumulated. Never grow up. Therefore, a voltage drop due to short circuit or electric leakage is prevented.

  Furthermore, when the nozzle cover includes the inward flange, the creeping distance from the spray nozzle to the electrode is increased. For this reason, even if spray droplets adhere to the creeping surface, a considerable spray time is required until a continuous film of spray droplets is formed between the spray nozzle and the annular electrode. Therefore, also at this point, a voltage drop due to a short circuit or electric leakage is suppressed.

  According to the present invention, since it is not necessary to use a compressor, both labor and cost can be saved.

  As a preferred embodiment, the nozzle cover has a cover body that covers the periphery of the spray nozzle, the inward flange, and is coupled to the cover body to hold the electrode between the cover body. A cap is provided, and the air inlet is located in front of the spray nozzle in the vicinity of the cap from a rear position of the spray nozzle that is closer to the cover body by a predetermined distance than the base of the cover body toward the spray nozzle. It can also be opened over a position (Claim 2).

  According to this embodiment, the air taken in from the intake port flows along the inner surface of the nozzle cover and is discharged along with the spray droplets in the spray direction. A continuous flow toward the spray nozzle side through the nozzle cover is formed. This continuous flow becomes an air curtain-like shielding layer and prevents movement of droplets in the direction of the base portion of the nozzle cover. For this reason, it is difficult for droplets to adhere to the base portion of the cover body, and the formation of a continuous film by the droplets is suppressed, so that a voltage drop due to a short circuit or leakage is also suppressed.

  As a further preferred embodiment, the total area of the intake ports is larger than the total area of the plurality of exhaust ports and does not exceed 1/2 of the total area of the peripheral surface of the cover body. It can also be a range (Claim 3).

  According to this embodiment, the negative pressure generated when the liquid is sprayed from the spray nozzle can be efficiently used without impairing the function of protecting the electrode by the nozzle cover and compensating the insulation thereof. The amount of air flow necessary for the prevention of droplet adhesion and peeling is ensured.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

  1 is a partially cutaway side view of an electrostatic spraying apparatus according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of the electrostatic spraying part of FIG. 1, and FIG. 3 is an electrostatic spraying of FIG. FIG. 4 is a side view of the electrostatic spraying part of FIG. 3.

  The electrostatic spraying device according to the present invention is a device for charging fine spray droplets of a conductive liquid and attaching them efficiently to an object. For example, for spraying agricultural chemicals, fertilizers, etc. on agricultural products. It is suitable for use. In FIG. 1, an electrostatic spray device provided with a handheld spray tub is shown as an embodiment of the present invention. However, this is merely an example, and a number of electrostatic spray units along a long boom. It is of course possible to apply the present invention to a traveling boom sprayer provided with

  As shown in FIG. 1, an electrostatic spraying device 1 according to an embodiment of the present invention includes a handheld spray tub 4 having an electrostatic spraying portion 2 at a front portion and an operation portion 3 at a rear portion. Yes. The operation unit 3 includes a spray cock 5, a power switch 6, and a rear grip 7 having a shape suitable for an operator to hold with one hand. A storage battery 8 as a power source is housed in the rear grip 7 in a replaceable manner.

  The electrostatic spray unit 2 includes a spray nozzle 9 that diffuses and sprays a liquid into fine droplets, and an electrode 10 that is disposed in the vicinity of the outside of the diffusion range of the droplets and applies electric charges to the droplets. A nozzle cover 19 that covers the periphery of the spray nozzle 9 and holds the electrode 10 is provided. In the present embodiment, the electrode 10 is an annular electrode and is concentrically disposed in front of the spray nozzle 9 in the spray direction. The liquid in the spray liquid tank 11 is pumped to the spray nozzle 9 by the pump 12. At the same time, electric power necessary for applying static electricity is supplied from the storage battery 8 to the annular electrode 10. The droplet S sprayed from the spray nozzle 9 is discharged into the atmosphere through the space in the annular electrode 10 while diffusing. The spray droplet S is charged by the annular electrode 10 when passing through the annular electrode 10. For this reason, the adherence of the spray droplet S to the object having the reverse polarity is improved.

  In the present embodiment, a booster 13 is disposed in the vicinity of the annular electrode 10 in order to improve safety and suppress voltage loss during power transmission. The booster 13 boosts the voltage of electric power supplied from the storage battery 8 at a low voltage of about 6 V to, for example, about 4.5 kV and supplies the boosted voltage to the annular electrode 10.

  The spray tub 4 includes a long and narrow tub tube 14 made of plastic having good chemical resistance as a casing. The electrostatic spray unit 2 is supported on the front end portion 14 f of the soot tube 14, and the operation unit 3 is supported on the rear end portion 14 r of the soot tube 14. In the soot tube 14, an electrical wiring 15 for supplying electric power to the booster 13 and a liquid supply pipe 16 for supplying the spray liquid to the spray nozzle 9 are accommodated.

  Further, a front grip 17 is attached to the soot tube 14 at an appropriate position between the front end portion 14f and the rear end portion 14r. A suspension ring 18 for connecting a shoulder strap (not shown) is attached to the rear of the front grip 17. The operator can perform the spraying work by suspending and supporting the spray basket 4 with the shoulder strap and holding the front grip 17 and the rear grip 7.

  As shown in FIGS. 2 and 3, the nozzle cover 19 of the electrostatic spraying section 2 is detachable into a cup-shaped cover body 20 that opens in the spraying direction and an opening 21 of the cover body 20. A cap 22 to be joined is provided. The spray nozzle 9 is retracted from the opening edge of the cover body 20 to the back side (base 20a side), and is concentrically disposed and accommodated in the cover body 20. The annular electrode 10 is sandwiched between the cover body 20 and the cap 22 and held concentrically therewith. The cover body 20 has an action (spray liquid drop blocking action) for preventing the spray liquid droplets S discharged to the outside of the nozzle cover 19 from adhering to the periphery of the spray nozzle 9. The cap 22 has an effect of holding the annular electrode 10 with the cover body 20.

  The cover body 20 is formed with an intake port 23 for taking in external air A1 with a negative pressure generated by spraying the liquid from the spray nozzle 9. The number, shape, size, and disposition position of the air inlets 23 should be set within a range that satisfies the following requirements in consideration of air intake and spray droplet blocking performance by the cover body 20. preferable.

  First, the total area of the intake port 23 is larger than the total area of a plurality of exhaust ports 29 described later, and does not exceed 1/2 of the total area of the peripheral surface of the cover body 20. It is preferable to do this. In this way, the negative pressure generated when the liquid is sprayed from the spray nozzle 9 can be used efficiently, and the amount of air flow necessary for suppressing adhesion and peeling of the droplets is ensured.

  Further, as shown in FIG. 4, the air inlet 23 is located near the cap 22 from a rear position of the spray nozzle 9 that is closer to the spray nozzle 9 than the base portion 20 a of the cover body 20 by a predetermined distance. It is preferable to open over the front position of the spray nozzle 9. In this case, as shown in FIG. 3, the air A1 taken in from the intake port 23 flows along the inner surface of the nozzle cover 19 and is discharged in the spraying direction as an airflow A3. A continuous flow (A1 + A3) from the periphery of the intake port 23 toward the spray nozzle 9 through the nozzle cover 19 is formed without interruption. This continuous flow becomes an air curtain-like shielding layer and prevents the movement of the droplet S in the direction of the base portion 20a of the cover body 20. For this reason, the droplets S are less likely to adhere to the base portion 20a of the cover body 20, and the formation of a continuous film by the droplets S is suppressed, so that a voltage drop due to a short circuit or electric leakage is also suppressed. .

  In the present embodiment, it is desirable that the total area of the air intake port 23 be at least 4 square centimeters or more, so that the convenience of cleaning is taken into consideration, as shown in FIGS. Four intake ports 23 having a large size of about 5 cm 2 are formed at equiangular intervals from the vicinity of the end portion 9a to the vicinity of the cap 22. Accordingly, the air curtain-like continuous flow is caused to flow around the entire circumference of the spray nozzle 9 in the nozzle cover 19 without impairing the function of protecting the annular electrode 10 by the nozzle cover 19 and compensating the insulation thereof. Can be formed more reliably. As a result, the droplets S are less likely to enter the base portion 20a of the cover body 20, and are less likely to adhere. In addition, even with the cap 22 attached, a rod-shaped cleaning tool (not shown) can be inserted from the air inlet 23 to clean the inner peripheral surface of the cover body 20 and the peripheral surface of the spray nozzle 9.

  As shown in FIG. 2, a plurality (four in the illustrated example) of electrode stays 24 are formed on the inner surface of the cover body 20 at appropriate angular intervals. Each of the plurality of electrode stays 24 includes a notch-shaped electrode receiving portion 25. On the electrode receiving portions 25, the annular electrode 10 having an outer diameter smaller than the inner diameter of the opening 21 of the cover body 20 is placed.

  One of the plurality of electrode stays 24 is a thick stay 24a, and a projection 26 is formed on the electrode receiving portion 25 of the thick stay 24a. The protrusion 26 is fitted into a positioning hole 30 formed in the annular electrode 10. The protrusion 26 is formed of a conductor, and the high voltage of the booster 13 can be applied to the annular electrode 10 through the protrusion 26.

  As shown in FIGS. 2 and 3, the cap 22 includes an inward flange 27 for holding the annular electrode 10. By providing the inward flange 27, the annular electrode 10 having an outer diameter smaller than the opening diameter of the cover body 20 can be held by the nozzle cover 19. A cylindrical electrode retainer 28 extending toward the annular electrode 10 is integrally formed at the inner peripheral edge of the inward flange 27. The annular electrode 10 is held between the electrode retainer 28 and the electrode receiving portion 25 by screwing the cap 22 into the outer periphery of the opening 21 of the cover body. In the inward flange 27, the plurality of exhaust ports 29 are formed at positions on the outer side in the radial direction of the annular electrode 10 at intervals in the circumferential direction.

  In the above configuration, when liquid is ejected from the spray nozzle 9, a negative pressure is generated in the nozzle cover 19 by being pulled by the flow of the spray liquid. Therefore, external air is introduced from the intake port 23 into the nozzle cover 19. A1 is inhaled. The air A <b> 1 taken into the nozzle cover 19 flows along the inner surface of the cover body 20 and the outer peripheral surface of the spray nozzle 9. A part A3 of the air A1 passes through the annular electrode 10 and is discharged together with the spray droplets S in the spraying direction. Therefore, the spray droplets S are prevented from adhering to the inner surface of the cover body 20 and the outer peripheral surface of the spray nozzle 9, and even if the spray droplets S are adhered, the airflow is accumulated before being accumulated. Since they are separated by A1 and A3, they do not grow into large droplets.

  The other part A2 of the air A1 taken into the nozzle cover 19 is discharged from the exhaust port 29 in the spraying direction. For this reason, the droplet S hardly adheres to the inside of the nozzle cover 19, particularly, in the vicinity of the inner surface side of the inward flange 27. So that it does not grow into large droplets. Therefore, it is difficult to form a continuous film of the spray droplets S in the nozzle cover 19, and a voltage drop due to electric leakage or short circuit is prevented.

  Further, since the cap 22 includes the inward flange 27 and the electrode presser 28, the creeping distance from the spray nozzle 9 to the annular electrode 10 is increased. For this reason, even if the spray droplet S adheres to the creeping surface, a considerable spray time is required until a continuous film of the spray droplet S is formed between the spray nozzle 9 and the annular electrode 10. Will be required. Therefore, even at this point, a voltage drop due to leakage or short circuit is unlikely to occur.

  Further, the air A1 taken in from the intake port 23 becomes a continuous flow (A1 + A3) toward the spray nozzle 10, and the spray droplets S that have entered the nozzle cover 19 are transferred to the cover body 20 by the continuous flow. It acts as an air curtain-like shielding layer that prevents floating movement toward the base portion 20a side. For this reason, it becomes difficult for the droplets S to adhere to the base portion 20a of the nozzle cover 19 (the cover body 20), and the formation of a continuous film by the droplets S is suppressed. This point also contributes to prevention of voltage drop due to short circuit or leakage. In particular, according to the present embodiment, since the plurality of exhaust ports 29 are provided, air does not stay inside the inward flange 27 or the back side of the annular electrode 10, so that the air curtain-like continuous flow ( The generation of A1 + A3) becomes even more reliable.

It is a partially cutaway side view of the electrostatic spraying apparatus which concerns on one Embodiment of this invention. It is a disassembled perspective view of the electrostatic spraying part of FIG. It is an expanded sectional view of the electrostatic spraying part of FIG. It is a side view of the electrostatic spraying part of FIG.

Explanation of symbols

9 Spray nozzle 10 Electrode (annular electrode)
DESCRIPTION OF SYMBOLS 19 Nozzle cover 20 Cover main body 20a Base part of cover main body 22 Cap 23 Intake port 27 Inward flange 29 Exhaust port A1 Outside air S Droplet (spray droplet)

Claims (3)

  A spray nozzle (9) that diffuses and sprays the liquid into fine droplets (S), and is disposed in the vicinity of the outside of the diffusion range of the droplets (S) to impart electric charges to the droplets (S). An electrode (10) and a nozzle cover (19) covering the periphery of the spray nozzle (9) and holding the electrode (10) are provided, and the nozzle cover (19) is configured to receive liquid from the spray nozzle (9). An intake port (23) for taking in external air (A1) with a negative pressure generated by spraying, and an inward flange (27) for holding the electrode (10) are provided. 27) The electrostatic spraying apparatus in which the several exhaust port (29) is formed in the position which becomes the outer side of the said electrode (10) at intervals in the circumferential direction.   The nozzle cover (19) includes a cover main body (20) that covers the periphery of the spray nozzle (9) and the inward flange (27), and is coupled to the cover main body (20) to connect the cover main body (20). ) And a cap (22) for holding the electrode (10), and the air inlet (23) is located on the cover body (20) more than the base (20a) of the cover body (20). The spray nozzle (9) is opened from the rear position of the spray nozzle (9) moved to the spray nozzle (9) side by a predetermined distance to the front position of the spray nozzle (9) in the vicinity of the cap (22). The electrostatic spraying device according to claim 1.   The total area of the intake port (23) is larger than the total area of the plurality of exhaust ports (29) and does not exceed 1/2 of the total area of the peripheral surface of the cover body (20). The electrostatic spraying device according to claim 2, wherein

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