JPH0415022B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid container device for electrostatic spraying.

GB 1569707 discloses a device for electrostatic spraying of liquids. The device is of simple construction with low power consumption (no moving parts and easily removable batteries) and is therefore hand-held, especially for applications where a large power source is not readily available, e.g. when spraying crops. Suitable for use as a sprayer. Electrostatic spraying of crops also has the benefit of promoting uniform application to the crop, the spray is attracted to the underside of the leaves instead of just covering the exposed surface, and is wasteful at best and wasteful at worst. This has the benefit of reducing drifting of the spray which is dangerous to the surrounding environment.

The device described in GB 1569707 basically consists of a discharge nozzle, a field enhancing electrode arranged around the nozzle, a container for supplying the liquid to be atomized to the nozzle, and a high voltage applied to the nozzle. and a high voltage generator applied to the electric field enhancing electrode, the electric field enhancing electrode being grounded. In this way, an electric field strong enough to atomize the liquid passing through the nozzle can be generated between the nozzle and the electrode.

This device is particularly suitable for applying insecticides in small or very small volumes (typically spray application rates of 0.5 to 10 liters of spray liquid per hectare). Although small volume or microvolume sprays offer some recognized benefits and are particularly suitable when water is not readily available as a spray diluent, they also have one disadvantage. Naturally, they must use relatively concentrated insecticide compositions. Such compositions are often somewhat toxic to humans and it is therefore desirable to handle them as little as possible. A particular danger lies in pouring toxic liquids into drinking bottles.

The most useful insecticide sprayer must be reliable and adaptable. Desirably, it is necessary to be able to spray various types of insecticides. Different pesticides have different electrical properties and result in different compositions that need to be sprayed with different droplet sizes for optimum effectiveness. In the device described in GB 1569707, the droplet size and atomization properties can be effectively and advantageously controlled by varying the applied voltage, but also the surroundings to suit the composition to be atomized. It is necessary to adjust the dimensions of the nozzle and its position relative to the electrode. It is often difficult to do this reliably in the field. Additionally, pesticide sprayers (sprayer tank, spray tube and nozzle) usually need to be thoroughly cleaned after each application of different pesticides, otherwise
For example, if herbicide remains, it can damage the crops that are to be sprayed for disinfection. The need for such cleaning is increased if the compositions are to be sprayed electrostatically as contamination will affect their electrical properties. Thorough cleaning may damage the nozzle, resulting in incorrect spray distribution.

It is an object of the present invention to provide an electrostatic spraying liquid which can alleviate or solve many of the problems mentioned above and which is suitable for use in an electrostatic spraying device of the kind described in the specification of Japanese Patent No. 1189213. An object of the present invention is to provide a container device.

According to the invention, a high voltage generator, a power source,
consisting of a holder with a field-enhancing electrode and an electrical connection connecting the field-enhancing electrode to one output terminal of the high-voltage generator, and a container of the liquid to be electrostatically sprayed, adapted to be attached to the holder. A liquid container apparatus for electrostatic spraying is provided, wherein the liquid container includes a spray nozzle having at least a portion of its surface electrically conductive, and a liquid container with the spray nozzle adjacent to and insulated from the field-enhancing electrode. an attachment device for placing a container of liquid in the holder; and when a container of liquid is placed in the holder by the attachment device, electricity extends from the spray nozzle to a contact on the attachment device that can be connected to another output terminal of the high voltage generator. It is characterized in that it comprises a connecting body and a closing seal for closing the spray nozzle before mounting it on the holder.

Further, in this invention, a high voltage generator;
The holder, which includes a power source, a field-enhancing electrode, and an electrical connection connecting the field-enhancing electrode to one output terminal of the high-voltage generator, further includes a spray nozzle adjacent the field-enhancing electrode and a container for liquid. an attachment device complementary to an attachment device on the container of liquid disposed in the holder, the complementary attachment device comprising:
It includes an electrical contact complementary to the electrical contact on the container of liquid and an electrical connection connecting the complementary electrical contact to another output terminal of the high voltage generator.

Furthermore, according to another invention of the present invention, in a liquid container device for electrostatic spraying, the container attached to the holder includes a neck portion to which a conductive nozzle is attached, and the conductive nozzle has a nozzle body, The nozzle body has a mouth for supplying liquid from the container and an air passage for passing air into the container. the height is at least twice its diameter, and the upper end of the inner tube extends at least into the neck of the container, and the mouth of the nozzle is located between the radial distance between the adjacent lower ends of the outer tube and the inner tube. A plurality of ribs are provided on one surface of the outer tube and the inner tube to separate the one tube from the other tube and form a passage for passing liquid from the container to the mouth, and an air passage is provided on one surface of the outer tube and the inner tube. is characterized in that it consists of a plug supported in a hole in the upper end of the inner tube, the plug and the hole in the upper end of the inner tube forming an extending passageway through which air can enter the container.

In this specification, the term "conductive surface" is intended to include semiconductive surfaces.

Before mounting in the holder, the nozzle of the container must be sealed to prevent leakage. One or more conventional sealing devices may be used, such as a screw cap or a metal foil seal or both on the nozzle. The seal on the container may preferably be opened only when the container is installed in the holder. Such opening operations may occur during or subsequent to such installation, and further opening may be performed mechanically or electrically. Therefore, during the process of attaching the container to the spray device, the knife or spike on the holder cuts or punctures the metal foil on the nozzle of the container. The container nozzle may be sealed by a valve, such as a spring-biased ball valve that is opened during installation by contacting a detent in the holder. In such devices, the container orifice automatically closes when removed from the device, which is particularly useful when the container still contains liquid.
The same desired objective may also be achieved using an electrostatic valve of the type described in the pending application "Electrostatic Valves" (EPO Application No. 80302767, filed August 12, 1980).

Preferably, the holder is provided with a device for maintaining one output terminal of the high voltage generator at or near earth potential. Such a device may be a conductor connected to ground, such as a ground wire trailing dangling from the holder. If such a device is provided, preferably the ground terminal of the high voltage generator is connected to the field enhancing electrode rather than to the nozzle of the container. Charging of the spray is therefore done by direct contact rather than by induction, and a relatively strong electrostatic field is generated which carries the spray to its (earthed) target.

If necessary, one of the two electrical connections between the field-enhancing electrode and the nozzle of the container and the terminal of the high voltage generator can be earthed, but a relatively direct connection is often advantageous. The field-enhancing electrodes may consist entirely of bare metal or may be covered in whole or in part with an insulating material.

For most effective operation, the container also requires a device to balance external and internal pressure during spraying, such as a vent or solid walls.

The container according to the invention is filled with a spray liquid suitably formulated by the manufacturer and, after closing the container, the spray liquid remains uncontaminated until it is actually sprayed. Sprayer tank, to avoid pollution
There is no need to clean the spray tube or nozzle,
Therefore, various products can be sprayed effectively without undue waste of time. Toxic hazards during operator handling are minimized and on-site operator errors during mixing and dilution are eliminated. After use, containers according to the invention can be returned to the manufacturer for refilling or disposed of. The container may be made using one or more elements of plastic material, for example by injection molding or blow molding, or a combination of the two. The conductive elements of the container (nozzles, contacts and connections) can be provided by metal inserts or by applying a conductive metal coating or painting to the surface of the container or by using partially conductive plastics.

One suitable type of power source is a battery. The amount of electrical energy required to atomize a liquid is fairly small. To give a typical example, a container is heated every second.
Contains 500ml of liquid that is sprayed at a rate of 0.1ml,
The droplet size is approximately 100μ and the charge to mass ratio is 5×10 ⁻³ Coulombs/Kg. The current carried in the droplets sprayed from the nozzle is therefore 0.5 μA. The required battery rating is considerably lower than that of most readily available flashlight batteries. An example of another type of power source that can be used in this invention is a solar cell. Suitable high voltages for use in this invention range from about 1 to 30 KV, and most preferably from about 5 to 25 KV.

Specific embodiments of the present invention will be described below with reference to the accompanying drawings.

Referring to Figures 1, 2, 3 and 5, the container consists of a generally flask-shaped body 1 made of blow-molded high-density polyethylene, with a collar 2 made of polyacetal and an injection-molded collar 2. Sealingly engaged. The container contains aromatic hydrocarbon solvent.
Contains a solution 40 containing 10% by weight of insecticide.

The collar 2 consists of two concentric cylinders 3, 4 which are joined near the ends to form an annular body. Inside the inner cylindrical body 4 is provided a polyacetal plug 5, the outer diameter of which is somewhat smaller than the inner diameter of the cylindrical body 4. The plug 5 is held in position within the cylinder 4 by an outwardly projecting ledge 6. The plug 5 thus cooperates with the cylinder 4 to form an annular channel 7 of capillary size through which the spray liquid can pass.
is formed. The stopper 5 is also a capillary tube 8 made of polythene.
The capillary tube 8 extends upwardly into the body 1 of the container. The annular nozzle formed by the combination of plug 5 and cylindrical body 4 is closed by a sealing cap 9 (shown only in FIG. 3) to prevent liquid leakage.

The rim 17 of the inner cylindrical body 4 is coated with conductive paint to form an annular conductor. This conductive rim 17 is connected to a brass contact stud 19 on the outside of the collar 2 via a conductive paint strip 18 provided on the inside of the cylinder 4 and on the top rim of the collar 2. To prevent electrical current from leaking through the spray liquid,
The conductive strip 18 is protected within the body 1 of the container by an insulating varnish. A protruding key 20 is also formed on the outside of the collar 2.

Referring now principally to FIG. 4, the container holder consists of a hand-held body 21 with a variable high voltage generator 22 (233P, 0-20 kilovolts, 200 microamp module). . This body 21 is generally of the elongated type and terminates in a ring 23 of rigid plastics material, the inside of which is the collar of the container.
be made to receive. The key groove 24 corresponds to the key 20 on the collar 2. A metal annular body 25 is mounted around the ring 23, and this metal annular body 25 acts as a field-enhancing electrode. Brass contact studs 27 are provided inside ring 23 for contact with studs 19 on the container. The power source 26 consists of a stack of dry cell batteries housed within the body 21 of the holder. The positive terminal of power supply 26 is connected to switch 29 via an insulated electrical conductor 28.
This switch 29 connects the positive terminal of the power supply 26 to the positive input terminal of the high voltage generator 22 via the conductor 30 in the on state. The negative pole of power supply 26 is grounded via insulated electrical conductors 31 and 32, conductor 32 being a metal wire with a bare end that is dragged along the ground. Contact stud 2
7 is connected to a high voltage output terminal 34 of the high voltage generator 22 via an insulated electrical conductor 33. The negative output terminal 35 of the high voltage generator 22 is connected to the ground wire or conductor 32 and to the metal ring 25.

In operation, the container is placed in an upright position and the sealing cap 9 is removed. The ring 23 of the holder is then positioned on the container collar 2 and pressed into place, and the two engaging parts are pushed into each other. The ring 23 thus grips the collar 2 sufficiently to hold the container in place, i.e. the key 20 in the container engages the key groove 24 and the contact studs 19, 27 are in contact with each other. hold. The circuit thus formed is
As shown in the figure. The holder is used to invert the container over the target to be sprayed, and liquid begins to drip from the channel 7. Switch 29 is immediately turned on. This causes a current to flow from the power source 26 to the high voltage generator 22, which results in a high potential (preferably 20 kilovolts) being supplied from the terminal 34 to the conductive surface or rim 17 of the cylinder 4 via the contact studs 27, 19. be done. A strong electrostatic field is thereby generated between the charged nozzle or rim 17 and the grounded metal ring 25 (acting as a field-enhancing electrode). The liquid exiting adjacent the rim 17 is thereby atomized and sprayed downwardly towards any desired target as a fine spray of controlled particle size. The decrease in pressure within the container that occurs when the liquid leaves the container through the annular passage 7 is
The pressure is equalized by the entry of air through the central capillary tube 18. The spraying action is stopped by turning off the switch 29 and turning the mouth of the container upwards.

Various modifications to the apparatus described above will be apparent to those skilled in the art. Although the containers are disposable in the illustrated embodiment, reusable containers may also be used.

The device is equipped with an earth connection conductor in the form of a bare metal wire that is trailed. This is a disadvantage because it can lead to stagnation or death. The device works best with a ground connection, but it need not be of low resistance. The conductor for the earth connection may be, for example, a metallized strip along the handle of the holder. When a worker grasps the handle, an electrical path is created through the worker's body to ground. Although this path has a high resistance, it has been found to be generally adequate. Experiments have shown that in this type of equipment the voltage at the vessel electrode can be approximately 100 or 200 volts above ground even when the operator is wearing rubber boots in relatively dry conditions. . Such a voltage at the electrode differs little from ground voltage compared to the potential at the nozzle which is several thousand volts. The electric current flowing through the worker's body is not dangerous at all, and is so small that the worker does not feel anything.

Other embodiments of the invention, which are more suitable for mass production using plastic molding techniques, are shown in Nos. 7 to 11.
As shown in the figure. The container 48 shown in FIGS. 7 and 8 has a bottle 49 formed by blow molding using clear polyethylene terephthalate.
9 has a shoulder 50 with a thread 52 on the outside and a neck 51 with a thread 53 on the outside. The neck 51 supports an annular nozzle 54 screwed onto it. The annular nozzle 54 is injection molded using a conductive plastic material (nylon containing 30% carbon black by weight) into two pieces 55, 56, which constitute the outer and inner wall elements of the annular nozzle 54, respectively. The outer wall element 55 consists of a tube 58 with a flared skirt 59 at its upper end, which skirt 59 is provided with an internal thread 60 and an external thread 61. An elastically deformable flange 63 extends outward from the upper end of the skirt 59.

A set of ratchet teeth 64 are formed around the inner circumference of skirt 59 below internal thread 60. The internal thread 60 in the skirt 59 is
9, i.e. the internal thread 6
0 and screw 53 are screwed together, ratchet teeth 64 engage a set of ratchet teeth 65 secured to the outer edge of neck 51 of bottle 49. This ensures that once the bottle 49 and nozzle 54 are assembled, they cannot be separated again. A peripheral portion 66 at the base of the skirt 59 is provided with an elastic rubber O-ring 67.
This O-ring 67 supports the nozzle 54.
and the edge of the neck 51.

Tube 58 includes seven vertical ribs 68 separated by passages 69. Inside the tube 58 is an annular nozzle 57.
An inner wall element 56 is carried. This inner wall element 56 is also generally tubular in shape and has ribs 6
tube 5 by pushing into tube 58 against 8.
8 and a head 72 of the rib 68.
It consists of a central radial flange 71 which abuts, and an upper part 73 with a mouth 74 which is partially closed by screwing in a threaded bolt 75. The mouth 74 has three splines 76 from which a portion of the thread of the bolt 75 is exposed. The bore of the port 74 is smooth and unthreaded. The lower end of the bottom portion 70 has an inner wall element 56
a peripheral recess forming an annular orifice 78 between the outer wall element 55 and the outer wall element 55 . Passage 69 communicates with this annular orifice 78.

A nylon cap 80 is shown in FIG. 11 that can be screwed onto nozzle 54 to retain liquid during shipping and storage. This cap 80 has an internal thread 82 that engages an external thread 61 on the nozzle 54.
It has a skirt 81 equipped with. This skirt 81 has an independent wall 86 having an inner circumferential projection 83 which in use forms a liquid-tight seal against the outer wall of the tube 58. A long projection 85 projects upwardly from the base 84 of the cap 80, i.e. it does not provide any sealing effect in use, but it almost fills the space between the bolt 75 and the projection 83 and allows the cap 80 to be removed. The amount of liquid lost during this process is minimized.

9 and 10 show a holder 9 for the container 48, consisting of a plastic support 89 and a carrying handle 91.
0 is shown. Support 89 is made of a rigid, non-conductive plastic material (eg, glass-filled nylon) and includes two short coaxial hollow cylinders 92, 93 joined by a beveled shoulder 94. The upper cylindrical body 92 is provided with an internal thread 95 which receives and connects with the external thread 52 of the bottle 49. The lower cylinder 93 is made wide enough to allow the nozzle 54 fitted with the cap 80 to pass therethrough with a small gap. The bottom of the cylinder 94 is provided with an outwardly directed radial flange 96. Immediately above this flange 96 and at the base of the cylinder 93 is a bare metal ring 97 . A large ear portion 98 is provided on one side of the support body 89, and this ear portion 98
is a socket 99 for receiving the end of the carrying handle 91.
and a rod of insulating plastic material (such as fiberglass). Handle 9
Two electric conductors 100 and 101 are arranged inside the 1, and the conductor 100 is a 25KV electric wire carried by a handle 91.
It is connected to one output terminal of the high voltage generator 102, and the conductor 101 is grounded. Conductor 10
0 is threaded into a blind hole 103 adjacent the inner surface of shoulder 94 and contacts a metal round head screw 104. The conductive wire 101 passes through the hole 105 and is connected to the metal ring 97. As shown in the circuit diagram of FIG. 10, the high voltage generator 102 is powered by four 1.5 volt flashlight batteries 106 via a spring loaded pushbutton switch 107. High voltage generator 102, battery 106 and switch 10
7 are all attached to the handle 91. The ground connection 108 is made via a bare wire trailed through the plastic twine substrate.

In use, the bottle 49 is first filled with a suitable liquid for spraying (e.g. 10% sterile by weight with a resistivity of 1 x 10 ⁸ Ωcm and a viscosity of 5 centistokes, measured at 20°C in a hydrocarbon solvent). (containing a drug) can be put in. Then, screw the nozzle 54 into the screw 53.
and engage the ratchet teeth 64, 65 to secure the nozzle 54 in position. Thereafter, the cap 80 is screwed onto the screw 61. The container 48 thus prepared is transported to the place where it is to be used.
At that location, the container 48 is screwed into the holder 89 by screws 52,95. The flange 63 has a screw 10
Contact with the head of 4. The handle 91 is used to hold the container 48 with the nozzle facing down toward the target to be sprayed, and the handle 91
0 is removed. Liquid begins to drip from the annular orifice 78 and air is drawn into the container through the central hole in the insert or inner wall element 56. In order for air to enter the container, the screw of the bolt 75 and the opening 7 are used.
It is necessary to pass along the long spiral groove formed between the smooth inner surface of 4. High voltage generator 102
is activated by pressing switch 107;
A potential of 25 KV is thereby supplied to the nozzle 54 through the conductor 100, the screw 104 and the flange 63. Nozzle orifice 7 charged in this way
A strong electric field is generated between 8 and ground conductor 97. This causes the liquid to band away from the orifice 78 and become uniformly sized, highly charged particles that are attracted to and evenly coat the target.

Nozzles of the configuration shown in Figures 7-11 produce a steady flow rate after a short period of equilibrium (on the order of 45 seconds). The equilibrium flow rate of a liquid of a given viscosity is
and the length and cross-sectional area of the helical air outflow channel. In the illustrated embodiment, 7
The two passages 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 an outer diameter of 13 mm, and the spiral air outlet passage has a length of about 9-10 cm, and its cross-sectional area is about 0.4 mm. mm ² and the resulting flow rate is approximately 0.07 ml/sec. Rather than changing the depth of the passages, the simplest way to increase or decrease the flow rate is to vary the number of passages, for example 4 or 16 passages, to roughly halve or double the flow rate, respectively. This nozzle provides a constant flow rate and is tilt insensitive, e.g.
It continues to operate satisfactorily even when held at an angle of 30 degrees.

Although the apparatus of the invention has been described for use in the insecticide spraying of compositions containing the insecticide in a particularly effective organic liquid carrier, it may also advantageously be used for the spraying of paints, e.g. by upholsterers. used. Container holders are advantageously hand-held, but they can also be self-propelled, mounted on a vehicle or part thereof, such as a tractor or an aircraft, when holding one or more containers. It may consist of a device. In this case, the power source may be a storage battery or a generator mounted on the vehicle.

[Brief explanation of drawings]

1 is a perspective view of a container according to the invention, FIG. 2 is an end view of a container according to the invention, FIG. 3 is a vertical sectional view of the container along line AA in FIG. 2, and FIG. 4 is a plan view of the holder. Figure 5 is a plan view of the collar of the container, Figure 6 is a circuit diagram showing the circuit formed when the container is attached to the holder, and Figure 7 is a vertical cross section of the nozzle and neck of the second container. 8 is a horizontal sectional view taken along line A-A in FIG. 7, FIG. 9 is a vertical sectional view of the holder of the second container, and FIG. 10 is a circuit diagram of the holder of FIG. 11 is a vertical cross-sectional view of the cap of the nozzle of FIG. 7; FIG. In the figure, 1: container body, 2: brim, 3, 4: cylindrical body, 5: stopper, 7: annular passage, 8: capillary tube, 9: sealing cap, 17: conductive rim, 18: conductive strip, 19: Contact stud, 21: Holder body, 2
2: High voltage generator, 23: Ring, 25: Metal annular body, 26: Power supply, 27: Contact stud, 28:
Electric conductor, 29: switch, 30-33: conductor,
34, 35: Output terminals.

Claims (1)

[Claims] 1. A high voltage generator, a power source, an electric field enhancing electrode,
It consists of a holder with an electrical connection for connecting the field-enhancing electrode to one output terminal of the high-voltage generator, and a container for the liquid to be electrostatically sprayed, the container being adapted to be attached to the holder. a spray nozzle having at least a portion of its surface electrically conductive; a mounting arrangement for positioning a container of liquid in the holder with the spray nozzle adjacent to and insulated from the field-enhancing electrode; an electrical connection extending from the atomizing nozzle to a contact on the mounting device which can be connected to another output terminal of the high voltage generator when the container is placed in the holder, and a closing seal which closes the atomizing nozzle before it is installed in the holder. A liquid container device for electrostatic spraying, comprising: 2. The container device according to claim 1, which is filled with a liquid suitable for electrostatic spraying. 3 a high voltage generator, a power source, an electric field enhancement electrode,
and an electrical connection connecting the field-enhancing electrode to one output terminal of the high-voltage generator. A complementary mounting device is provided to the device, the complementary mounting device connecting the complementary electrical contact to the electrical contact in the container of liquid and the complementary electrical contact to the high voltage generator. The container device according to claim 2, further comprising an electrical connection body connected to another output terminal of the container device. 4. Container device according to claim 3, comprising means for maintaining one output terminal of the high voltage generator at or near earth potential. 5. The container device according to claim 4, wherein the electric field enhancement electrode is grounded. 6. A container to be attached to the holder includes a neck portion to which a conductive nozzle is attached, and the conductive nozzle includes a nozzle body, a mouth portion for supplying liquid from the container, and an air passageway for passing air into the container. , the nozzle body is comprised of a vertically aligned coaxial outer tube and an inner tube, the outer tube is short and its height is at least twice its diameter, and the upper end of the inner tube is at least as wide as the container. extending into the neck of the nozzle, the mouth of the nozzle is formed radially between the adjacent lower ends of the outer tube and the inner tube, and a surface of one of the outer tube and the inner tube is and the other tube, a plurality of ribs forming a passageway for passing liquid from the container to the mouth;
characterized in that the air passageway consists of a plug supported in a hole at the upper end of the inner tube, the plug and the hole at the upper end of the inner tube forming an extending passageway through which air can enter the container. Liquid container device for electrostatic spraying. 7. Container device according to claim 6, wherein the neck is externally provided with a thread for engaging a threaded annular portion of the holder. 8. The outer tube has at its upper end a protruding resilient radial flange which is electrically connected to a high voltage contact stud in the holder.
Container device as described in Section. 9. Claim 6, wherein the seal cap includes a central member extending upwardly from the base of the seal cap to at least partially occlude the interior of the inner tube.
The container device according to any one of items 1 to 8. 10. The container device according to any one of claims 6 to 9, wherein the extension passage is formed by a groove of a helical thread.