KR890000528B1 - Containers for use in electrostatic spraying - Google Patents

Abstract

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Description

Containers for use in electrostatic spraying

1 is a vertical cross-sectional view of the nozzle and neck of the container.

FIG. 2 is a horizontal sectional view taken along the line A-A of FIG.

3 is a vertical cross-sectional view of the vessel holder.

4 is a circuit diagram of FIG. 3 holder.

5 is a vertical cross-sectional view of the cap for the nozzle of FIG.

* Explanation of symbols for main parts of the drawings

48: container 51: neck

54: nozzle 58: tube

68: rib 69: channel

71: flange 80: cap

84: Donation 90: Holder

96: flange

The present invention relates to a container for use in electrostatic spraying of liquids.

Applicant describes in British Patent 1,569,707 an apparatus for electrostatic spraying of liquids. The device has a simple structure that requires low power and can be easily operated by a dry cell without moving parts. It is particularly suitable for use as a portable nebulizer that can be used where large power sources are not readily available, for example in spraying crops. In addition, electrostatic spraying of crops has the advantage of performing a uniform covering of the plant, including the back of the leaves, instead of covering only the exposed surfaces, and reducing the drifting of the spray, which is harmful and wasteful to the surrounding environment.

The device described in the UK patent is essentially a discharge nozzle, a field strengthening electrode disposed and grounded around the nozzle, a vessel for supplying the liquid to be sprayed to the nozzle and a high voltage for applying a high voltage to the nozzle. It consists of a generator. Thus, an electric field strong enough to spray the liquid passing through the nozzle can be formed between the nozzle and the electrode.

The device is particularly suitable for coating low or extremely low doses of pesticides (typically with a spray coverage of 0.1-10 liters of spray liquid per hectare). Low or extremely low amounts of spray have several significant advantages and are particularly suitable where water is not readily available as a spray diluent, but has one drawback. Essentially, the spray should use a relatively concentrated pesticide composition. Such compositions usually have some toxicity to the human body, and for that reason contact with the body should be as small as possible. Especially dangerous is the penetration of toxic liquids into drinking water bottles.

Pesticide sprays must be reliable and adaptable for good action. It is desirable to be able to spray several different types of insecticides. Different pesticides have different electrical properties and have different structures that must be sprayed at different droplet sizes to provide the optimum effect. In the apparatus of British Patent No. 1569707, the droplet size and spray properties can be usefully and conveniently adjusted by varying the applied voltage, but the size of the nozzle and its position relative to the surrounding electrode can be sprayed according to the spray liquid. May require adjustment to suit. It is usually difficult to do this reliably in the fields. In addition, pesticide sprayers (spray tanks, spray tubes, and nozzles) must be thoroughly cleaned when spraying different pesticides, or residues of herbicides, for example, can damage the sprayed grain to remove mold. The need for such cleaning is increased when electrostatically spraying other compositions, since contamination can affect their electrical properties. Complete cleaning can damage the nozzles and cause inaccurate spraying.

Suitable containers for use in electrospray apparatus of the type described in British Patent No. 1,569,707, which can eliminate many of the aforementioned problems, are described in Applicants' published British Patent Application Nos. 2,030,060 and 2,061,769.

In the UK patent application, a liquid container to be electrostatically sprayed suitable for mounting on a holder to form a device comprising a power supply, an electric field strengthening electrode and an electrical connection for connecting the electrode to one input terminal of the high voltage generator when a high voltage is generated. The vessel has an electroconductive spray nozzle and mounting means for positioning the vessel in the holder, the mounting means having a nozzle, the mounting means having electrical contacts to connect the nozzle to the high voltage generator. have.

In order to provide really good results, such a container requires discharging the liquid at as many and constant flow rates as possible in its discharge cycle. It is also desirable that the discharge of liquid from such a container should be affected as little as possible by small movements of the container (sensitivity of rotation) or by small fluctuations in the angle (tilt sensitivity) at which the container is held.

It is therefore an object of the present invention to provide an improved container having an almost constant liquid discharge which is less susceptible to temperature changes and an improved tilt and rocking sensitivity.

Therefore, in order to achieve the above object, the present invention provides a bowl having an electrically conductive nozzle in the neck having a neck and an inner and outer wall, an inlet for discharging liquid from the bowl, and an air passage for supplying air into the bowl. A container configured to be mounted to a holder for electrostatic spraying liquid, the inner and outer walls having vertically aligned coaxial inner and outer tubes, the outer tubes being short and at least twice the height of diameter, The inner tube has an upper end extending at least into the neck of the vessel, the inlet being formed by radial spacing between adjacent lower ends of the tubes, ribs being provided on the surface of one tube so that the surface Spaced apart from the second tube, forming channels through and through the vessel to discharge liquid from the vessel to the inlet; The pore has a stopper supported in the inner tube and the upper end hole, and the stopper and the hole cooperate to provide a long passage through which air passes to enter the vessel.

A holder suitable for accommodating a container according to the present invention has a high voltage generator, a power supply for the high voltage generator, an electric field reinforcing electrode, an electrical connection for grounding the electrode, and a mounting corresponding to the mounting means on the container for positioning the container in the holder. Means; the spray orifice is adjacent the electrode and the nozzle is connected to the output terminal of the high voltage generator.

As used herein, the term "conductive surface" also includes semiconducting surfaces.

Prior to mounting on the holder, the container nozzles should be sealed to prevent liquid leakage. Conventional sealing means such as, for example, a screw cap seal on the nozzle may be used.

Means are preferably provided on the holder for maintaining one output terminal of the high voltage generator at or near ground potential. Such means may be, for example, a grounding conductor, such as a slack grounding conductor, which is dependent on the holder. If such means are provided, the grounded terminal of the high voltage generator is preferably arranged for connection to the field strengthening electrode rather than to the vessel nozzle. The spray bed is then performed by direct contact rather than by induction, and a strong electrostatic field is generated that transfers the spray liquid to its (grounded) target.

The field reinforcing electrode may be an exposed metal or may be completely or partially covered with an insulating material.

The container according to the invention can be filled by the manufacturer with a spray liquid of a suitable composition, and after the containers are sealed, the spray liquid remains uncontaminated until the actual spraying. There is no need to clean the spray tank, spray tube, or nozzle to prevent contamination, so that other products can be sprayed continuously without undue time loss. The risk of poisoning by the operator by the operator is minimized and errors by the field operator are eliminated during the mixing and dilution process. After use, the container according to the invention can be converted or discarded by the manufacturer for refilling. The containers can be made of one or more plastic materials, for example by injection molding or blow moulding or by their mixed method. The conductive elements (nozzles, contacts and connections) of the container may be provided by a metal insert, by the application of a conductive metal coating or paint to the container surface, or by using a partially conductive plastic.

A suitable form of power source is a capacitive battery. The amount of electrical energy required to atomize the liquid is significantly lower. As a representative example, the vessel capacity is 500 ml, spray rate is 0.5 ml per second, droplet size is about 100 microns and charge to mass ratio is 5 × 10 ⁻³ coulombs per kg. Thus the current of the droplets atomizing from the nozzle is 2.5 micro amps. Spray time is 1000 seconds at an input current of 15 milliamps, an input voltage of about 10 volts, and an output voltage of 20 kilovolts. Thus, the cell rating required to spray liquid from one such container is only 4 mAh at about 10 volts. This capacity is considerably lower than that of the most readily available torch batteries. Another form of power source that can be used in the present invention is a solar cell. In some examples of the invention, the power source may be supported in the container rather than in the holder. Suitable high voltages for use in the present invention are about 1-about 30 kilovolts, most preferably about 15-about 25 kilovolts.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The container 48 shown in FIGS. 1 and 2 is formed by a process involving blow molding from a transparent polyethylene terephthalate, and a neck portion having a shoulder 50 with an external thread 52 and an external thread 53. It consists of a bowl (49) having (51). The neck portion 51 supports the annular nozzle 54 in which the screw is formed. The nozzle is injection molded from a conductive plastic material (nylon containing 20% by weight carbon black) on the outer and inner walls of the nozzle. The outer wall of the part consists of a tube 58 and has a long skirt 59 at the upper end of the tube. The skirt is provided with inner and outer threads 60 and 61. From the upper end of the skirt 59, an elastically deformable flange 63

It extends outward.

Under the inner thread 60, one set of ratchets 64 is formed on the inner circumference of the skirt 59. Screw 60 on skirt 59 engages screw 53 on bottle 49. When they are screwed together, the ratchet 64 engages one set of ratchets 65 secured to the outer lip of the neck 51 of the vessel 49. This prevents the bowl 49 and the nozzle 54 from being separated when assembled. At the base of the skirt 59, a circumferential protrusion 66 supports the elastic rubber 0-ring 67, which acts as a liquid seal between the lip of the nozzle 54 and the neck 51.

Tube 58 has seven vertical ribs 68 separated by channels 69. The inner wall 56 of the annular nozzle 54 is supported in the tube 58. The inner wall is also tubular and has a bottom portion 70 that is press fit into the tube 58 and loosely engages the rib 68 and a central radial flange in contact with the head 72 of the rib 68. 71 and an upper portion 73 whose inlet is partially closed by a screw 75 having a screw groove formed therein. The inlet has three protrusions 76 exposing a part of the screw 75, and the inner hole of the inlet is smooth without screw grooves. At the lower end of the bottom portion 70, a circumferential groove portion for forming the annular orifice 78 is formed between the inner and outer side walls 55 and 56. As shown in FIG. Channels 69 are through the orifice 78.

5 shows a cap 80 made of high-impact nylon, which can be screwed into the nozzle 54 to retain liquid during transport and resistance. The cap includes a skirt 81 having an internal thread 82 that engages an external thread 61 on the nozzle 54. The skirt 81 has a wall 86 in which an inner circumferential protrusion 83 is formed which forms a liquid seal against the outer wall of the tube 58 in use. A long nose 85 protrudes upward from the base 84 of the cap 80, and in use the nose has no sealing function but occupies most of the space between the screw 75 and the protrusion 83 When removing the cap 80, the loss of liquid is minimized.

3 and 4 show the holder 90 for the container 48 composed of a plastic support 89 and a support handle 91. The support 89 is made of a rough, rigid, nonconductive plastic material (e.g. gas filled nylon or preferably talc filled polypropylene) and is connected by two short coaxial hollow cylinders connected by inclined shoulders 94. It consists of sieves 92 and 93. The upper cylindrical body 92 has an internal thread 95 for receiving and engaging the external thread 52 of the bottle 49. The lower cylinder 93 is wide enough to allow the nozzle 54 to support the cap 80 at small intervals. At the bottom of the cylindrical body 93 is formed a radial flange 96 facing outward. Immediately above the flange 96, a metal ring 97 peeled off the base of the cylindrical body 93 is disposed. A large lug 98 is provided on one side of the support 89, which lugs 99 for receiving one end of a sealing handle 91 of insulating plastic material (such as fiberglass). Has) Two electrical conductors 100 and 101 are arranged in the handle 91, and the conductive wire 100 is connected to one output terminal of the 25KV high voltage generator 102 supported by the handle 91. Conductor 101 is grounded. The conductive wire 100 is accommodated in a closed hole 103 adjacent to the inner axial surface of the shoulder 94 and has a head in contact with a round metal screw 104. As shown in the circuit diagram of FIG. 10, the voltage generator 102 is powered by a spring loaded pushbutton switch 107 by four 1.5 volt batteries 106. The voltage generator 102, the battery 106, and the switch 107 are all mounted on the handle 91. A ground connection 108 is provided through the bare wires tethered to the plastic base.

In use, the bottle 49 is first filled with a suitable spray liquid (eg, 10% by weight of the sterilant composition in a hydrocarbon solvent). The composition has a resistance of 1 × 10 ⁸ ohm-cm and a viscosity of 5 centistokes measured at 20 ° C. Next, the nozzle 54 is coupled to the screw 53 and the ratchets 63 and 65 are engaged to permanently secure the nozzle 54 in place. The container 48 thus formed is transferred to the place of use. Where used, screws 52 and 95 are used to couple to holder 89. The flange 63 contacts the head of the screw 104. Knob 92 is used to hold container 48 such that the nozzle is directed downward to the target to be sprayed, and cap 80 is removed. The spray liquid begins to fall through the annular portion 78 while the air is sucked into the vessel through the central hole of the inner tube 56. Air entering the vessel must pass along an elongated threaded groove formed between the screw of the nut 75 and the smooth inner surface of the inlet of the inner wall 56. The voltage generator 102 is actuated by pressing the switch 107 to provide a potential of 25 KV to the nozzle 54 through the lead 100, the screw 104 and the flange 63. A strong electric field is generated between the filled nozzle orifice 78 and the grounded conductor 97, which causes the liquid exiting the orifice 78 to pulverize the liquid stream into largely charged particles of uniform size. To evenly coat the target.

The shape of the nozzle shown in FIGS. 1-5 allows for a normal flow rate after a short time (about 45 seconds) to reach equilibrium. Equilibrium flow rates for liquids of a given viscosity depend on the width, depth and number of channels 69 and the length and cross-sectional area of the air passage channels. In the example shown, the seven channels 69 have a depth of 0.3 mm and a width of 1.6 mm, the annular orifice has a width of 0.3 mm and its outer diameter is 13 mm, and the spiral air passage has a length of about 9-10 cm. It has a cross-sectional area of about 0.4 square mm and the flow rate formed is about 0.07 ml / sec. For larger or smaller flow rates, the flow rate can simply be roughly halved or doubled by changing its number to, for example, 4 or 16 rather than the depth or thickness of the channel 69. In addition to providing a stable flow rate, the nozzle is satisfactorily continuous when it is maintained at an angle of, for example, 30% with respect to the inclination, for example.

Various modifications of the aforementioned devices are apparent to those skilled in the art. The illustrated container is intended for disposal after use, but a reusable container may also be made. Instead of a vertical air passage channel, for example, a long plug with a vertical groove may be used to provide the air passage.

The described device includes a grounded conductor in the form of an extended stripped metal wire, which has the disadvantage that it can become entangled. The device works well when it has a ground connection, but need not have a low resistance. The ground connection conductor may be, for example, a metal strip arranged along the handle of the holder. When the operator grips the handle, an electrical path to ground is established through the operator's body. This passage has a high resistance but is usually found to be suitable. As a result of the experiments, in this kind of arrangement, the voltage to the container electrode can be raised to about 100 or 200 volts higher than that of the ground even when the operator wears a relatively dry rubber shoe. The voltage of such an electrode is small, unlike that of ground, relative to the potential on the nozzle of the tapping bolt. The current flowing through the operator is so small that it is neither dangerous nor felt.

Although the devices of the present invention have been described for use in spraying compositions comprising pesticides in organic liquid carriers, for example, coatings or paints for decoration at home can also be used for spraying. The holder of the container is convenient to hold by hand, but it may be supported by a vehicle such as a tractor or aircraft when carrying more than one container. In this case, the power source may be a battery or a generator of the carrier itself.

Claims (9)

A bowl 49 having an electrically conductive nozzle 54 in the neck having a neck portion 51 and inner and outer walls 55 and 56, an inlet 78 for discharging liquid from the bowl 49, and In the container 48, which consists of air passages 75 and 76 for supplying air into the bowl and is mounted to the holder 90 for electrostatic spraying of liquid, the inner and outer walls 55 and 56 are vertically aligned. Coaxial outer and inner tubes, wherein the outer tube 58 is short and has a height of at least twice its diameter, and the inner tubes 70 and 73 have upper ends of at least the vessel 49. Extend into the neck; The inlet is formed by radial clearance 78 between adjacent bottom portions of the tubes; Ribs 68 are formed in the manifestation of one tube to form channels 69 in communication with the vessel 49 to keep the tube away from the second tube 70, 73 and also to drain liquid from the vessel to the inlet. and; The air passages 75 and 76 include a stopper supported in the hole of the upper end 73 of the inner tube, and the stopper and the hole cooperate to provide a long passage through which air passes when entering the vessel. Container for use in electrostatic spraying, characterized in that. The container for use in electrostatic spraying according to claim 1, characterized in that the neck portion (51) of the container has a screw groove on the outside so as to engage with the screw groove ring (95) on the holder (90). 3. An outer tube (58) according to claim 1 or 2, characterized in that the outer tube (58) has a radially projecting flange (63) at its upper end and is electrically connected to the high voltage contact stud (104) on the holder. Container for use in electrostatic spraying. 3. Electrostatic spraying according to claim 1 or 2, characterized in that it has a sealing cap (80) having a central member (85) extending upwardly from the cap base to at least partially fill the inside of the inner tube. For courage. 4. A container for use in electrostatic spraying according to claim 3, characterized by having a sealing cap (80) having a central member (85) extending upwardly from the cap base to at least partially fill the inside of the inner tube. The container for use in electrostatic spraying according to claim 1 or 2, wherein the long passage is formed by a spiral screw groove. 4. A container for use in electrostatic spraying according to claim 3, wherein said long passage is formed by a helical threaded groove. The container for use in electrostatic spraying according to claim 4, wherein the long passage is formed by a spiral screw groove. 7. A container according to claim 6, wherein said long passage is formed by a helical threaded groove.

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