KR19990035946A - Electrostatic nozzles for abrasive and conductive liquids - Google Patents

Abstract

Air spray induced charged spray nozzles are suitable for use with conductive liquids, solutions, suspensions or emulsions. The system is characterized by a high degree of spray charge with low induction electrode voltage and current. The main advantages are continuity, especially with relatively high concentrations of abrasive and conductive materials, and the widespread spray formation includes safe operation in stringent agricultural and industrial environments. The outer surface of the nozzle body part 1 is connected near the ground sprayer part and is maintained at floating or near ground voltage. The surface of the cover 2 adjacent the induction electrode 18 is maintained near the electrode 18 voltage. The high resistance path between the high voltage and low voltage portions of the nozzle is maintained and the electrode voltage or spray charge level does not significantly decrease when the nozzle surface is coated by spray or contaminated by conductive material present in the spray environment.

Description

Electrostatic nozzles for abrasive and conductive liquids

Several existing methods exist to charge and transport spray particles for the purpose of increasing the quality and efficiency of spray material that is mass delivered to the target point. Inductively charged types of electrostatic nozzles are often chosen for use in certain industrial and agricultural devices because they utilize the principle of corona, splice or electrohydraulic charging using voltages on the order of 25 to 50 kV to fully charge. This is because it is common to use lower input voltages and currents than other types of electrostatic nozzles, such as foundation nozzles. There are basically two types of spray induced charge systems in the prior art. The first kind is directed to nozzles which are positioned near relatively wide hydraulic, pneumatic or other forms of spraying zones and attain sufficiently high induced charge field gradients at operating voltages on the order of 5 to 15 kV. Examples of this form include those developed by Burls et al., Pay, Swanson, Sickles, Inculet, and the like. The second kind of induction-based device is located very close to the better formed spray zone, and because the electrode is located close to the spray zone, it is possible to develop a sufficient induced charge field gradient with an electrode voltage of only 1 to 3 kV. It is about. Examples of the latter form include those made by Row and Parmentar.

The magnitude of the force that the charged droplets electrically propel toward the target point is a function of the droplet charge level and the droplet size. Properly controlling the droplet size and proper charge can result in a significant improvement in efficiency, particularly in attaching the three-dimensional target to the concealment zone. Conventional air atomization inductively charged devices by row and parmenta successfully spray water droplets to a desired size range up to 100 mm in diameter for electrostatic effects and charge the droplets to a minimum desired degree of at least 3 mC / l. . These parameters result in at least a twofold increase in adhesion to complex target shapes, such as plant canopy, encountered in crop spraying, compared to similar uncharged sprays. However, when commonly used materials are mixed into the spray liquid and used in conventional nozzles, the degree of charge is significantly reduced over the time intervals considered for normal service life. For example, using a mixture of powdered conductive liquids or metals commonly used in spraying pesticides and foliar fertilizers during a half-day spray with a low nozzle (or a commercial product of the nozzle changed to a dielectric liquid tip), The degree of charge can be reduced to one fifth or less than that which can be obtained only by water. Continuous use of this type of additive in water causes irreversible damage to electrostatic spray nozzles and power supplies in contaminated environments encountered during industrial and agricultural spraying.

The degree of spray charge and the ultimate breakdown of the nozzle components are largely due to some electrical problems resulting from the formation of electrode attachments on the inner and outer nozzle surfaces. However, these attachments produce somewhat drifting current paths that traverse at any time across the surface of the nozzle and the wires and hoses attached to the nozzle. This electrical tracking phenomenon also occurs with relatively low voltages of approximately 1 to 3 kV with respect to internal electrode inductively charged nozzles, such as those disclosed in the Low and Parmenta patents. Eventually, conductive black carbon deposits are formed along this drift current path that etches the dielectric surface, creating a permanent electrical conductor that cannot be removed by the operator during normal cleaning operations. This electrical path can be formed on the inner and outer nozzle surfaces.

Drift Current on External Surface

It is most apparent that the drift current tracking path is formed on the outer dielectric nozzle surface which is affected by the humidity of the spray atmosphere and severe contamination by particles. The current path generally begins at the surface of the nozzle orifice near the high voltage electrode and extends outward from the electrode toward the outer surface of the low voltage when the exposed clean dielectric surface of the charged nozzle is wetted or contaminated. Since the contaminants create a resistive conduit that electrically grounds the electrode, the surface located between the electrode and the ground voltage is in a predetermined voltage state that is halfway between the electrode and the ground voltage, depending on its position and degree of surface contamination.

The first result of the drift current on the outer surface is to increase the power needs of the system, which tends to reduce the discharge voltage of the unregulated electrode power source of the nozzle. This proportionally reduces both the electrode voltage and the spray charge. When the insulating surface to which the grounded sprayer portion is to be separated from the electrode is sufficiently contaminated, the electrode current drawn from the power source increases very quickly. Under clean conditions, the low or parmenta nozzle draws only 20 mA with water. However, when the nozzle becomes conductive through contamination by atmospheric humidity, particles, or spray liquids, the effective resistance from the induction electrode to ground is reduced, and the resulting surface tracking results in a power discharge current of 200 depending on the power output of the power supply. Increase more than twice With unregulated power supplies normally used because of their inherent stability, the increase in current reduces the voltage to less than one-third of the emissions from its uncontaminated state. In addition, many power requirements reduce the number of nozzles that can be operated with a single electrostatic power source. Power demands due to surface defects have led some manufacturers of commercial inductively charged nozzles to use a separate power source for each nozzle that uses more discharge current than is needed for the operation of an uncontaminated nozzle. Using this design increases the complexity and cost of multi-nozzle systems, such as agricultural straight sprayers, and the available excess power accelerates dielectric surface destruction from electrical tracking and creates safety concerns. As disclosed in row name US Pat. No. 4,004,733 (patent cited herein by reference), it is desirable to connect the power supply directly to a charged nozzle or to embed the power supply in the nozzle. The advantage disclosed by Row is that it can avoid any high voltage leads that are sensitive to mechanical damage and can present an electrical hazard. Rowname's patent shows a power source directly connected to the nozzle portion containing the electrode. The problem with this embodiment is that the low voltage input wire is contaminated, and eventually the degree of insulation is degraded by electrical activity along the insulating surface. The potential difference between the conductor inside the low voltage line and the contaminants of the wire is usually near the electrode potential difference. Thus dielectric breakdown of the insulator is possible, especially if the insulator is vulnerable to mechanical damage or dielectric tracking damage. In addition, there is usually an electrical connector somewhere on the low voltage wire so that the nozzle can be easily removed. The inside of the connector is low voltage and the outside of the connector is high voltage because of the conductive paths formed on the connector surface by wire insulators and / or contamination. Therefore, in fact, the inside of the low voltage connector and the outside of the high voltage connector may fail due to the potential difference.

The device disclosed in the patent by Parmenta et al. Introduces an electrical tracking problem on the outer nozzle surface, from a nozzle outlet to a series of grooves on the outer wall of the nozzle and a grounded mounting bracket with a large radius flange around the nozzle. Attempts have been made to limit the current by increasing the insulation length of the surface. However, because the grooves and flanges are directly exposed to the dust and charged spray droplet groups, the grooves and flanges are fast enough conductors to maintain substantial current from the electrodes. In addition, deep grooves may be filled with a dry spray material, difficult to clean sufficiently, and may remain conductive after cleaning.

The second result of the drift current on the outer nozzle surface is to reduce the spray charge intensity due to the electrical connection with the liquid source through the seam of the liquid input connection of the nozzle body. When electrical connection is made with a normal ground liquid, the potential of the liquid is increased towards the potential of the induction electrode. The potential difference between the induction electrode and the liquid stream is reduced and consequently the degree of spray charge decreases proportionally.

Physical damage can result from contaminated insulating surfaces of wires connecting the nozzle component surfaces with grounded sprayer portions, electrical arcs near air tubes and liquid tubes. Current flows along the defective surface from the electrode or contaminated high voltage electrical connector, electrical arc occurs near the grounded sprayer portion, eventually corroding the hole with tubing, wire insulation causing liquid leakage, and direct shorting Expose the affected conductor to.

As a result, pitting from etching and electrical charge along the current path permanently damages the surface of important basic functionalities of the nozzle, such as the spray channel wall, liquid orifice tip, and the surface of the electrode. Corrosion from the electrical activity in these areas causes spray form breakdown and has a great impact on the degree of spray charge and sprayability.

Drift Current on Internal Surface

Charge flow across the contaminated outer nozzle surface causes the most visible physical damage to conventional air atomizing induction nozzles and causes a large amount of current to be drawn from the power source, but the inner surface is also susceptible to contamination. As a result, this contaminant reduces the spray charge when the potential upstream of the electrode is affected.

Some types of conventional inductively charged nozzles use a seal in the nozzle to insulate liquid from an electrode located within the nozzle. The dielectric surface of these seals can be sufficiently conductive by contaminants during decomposition to provide a current path to the liquid. The amount of current across the dielectric seal is not sufficient to cause electrical arc and surface etching. However, the electrical connection may be sufficient to increase the voltage of the liquid stream towards the voltage of the electrode, with the result that the inductive spray charged field is significantly reduced. Some older nozzles are designed so that the nozzle can be broken down into all the basic components. While this allows a conventional approach to each part for inspection and replacement, it has been found that some conductive current remains after normal cleaning and reassembly, exacerbating the problem of possible internal surface contamination.

One example of how accidentally contaminates the interior surface during degradation is in the low nozzle modified by the dielectric twin fluid tip. The base of this twin fluid tip is threaded to the nozzle body and during disassembly the seam is contaminated resulting in an electrical tracking path between the liquid channel and the drift surface currents originating in the electrode. It has been observed that this path causes the liquid upstream of the electrode to be 40-70% of the electrode voltage, resulting in a proportional reduction in spray charge.

In addition, internal contamination results in a small amount of spray material flowing back into the air channel when the air flow stops, at which time a conventional nozzle occurs. This contaminant creates a large current path on the surface between the electrode and the liquid orifice tip and liquid channel insulation where low voltage is desired. This surface can be fit by charging. Eventually, the hole develops in the dielectric material surrounding the liquid orifice tip or liquid channel, thus directly exposing the liquid channel to the electrode voltage and the pressurized gas cavity.

In previous commercial products of low nozzles, the twin-fluid tip and its corresponding threaded base are conductive and grounded. The cover is mounted on the exposed top of the electrode and the twin-fluid tip. The technique aims to fix the liquid to ground voltage despite the presence of drift currents. However, during normal use periods and during nozzle cleaning, the inner surface of the cover is contaminated. Thus, current travels from the electrode to the outside, across the contaminated cover seal, along the contaminated inner surface towards the exposed metal of the grounded twin-fluid tip. The liquid remains grounded, but the current path penetrates directly through the conductive twin-fluid tip and power dissipation is severely reduced and easily breaks down due to excessive current demand. As part of solving this problem, metal twin fluid tips were replaced with tips of the same design made of Delrin plastics. This slightly increases the life of the nozzle, but in the end the current path into the liquid stream has enough electrical arc to eventually create a groove between the seal surface and a continuous current path open to the liquid stream and the Delrin twin fluid tip and nozzle body Penetrates the seam between and.

Use a resistor on the power outlet

In some conventional electrostatic nozzles, such as Cycles, a gigaohm range resistor is provided between the power outlet and the nozzle electrode to prevent severe electrical arcs inside the nozzle and limit the current to the electrode for operator safety purposes. In addition, this resistor has a beneficial effect on limiting the outflow currents occurring at the electrode, but spray charges because very small outflow currents on the contaminated surface substantially drop the voltage across the high magnitude limiting resistors connected to the electrodes. The degree is reduced. When spray material or airborne dust clings to the dielectric nozzle, the effective resistance of the ground from the electrode is reduced to less than the resistance of the power supply series resistor to the extent that the current is adequately limited to a safe degree. In fact, when conventional nozzles are used in agricultural equipment, the nozzle electrode ground resistance is often reduced to less than 1 megohm. The schematic diagram shown in FIG. 13 illustrates the effect of the electrode voltage V _e on the case where a current limiting resistor R is provided between the nozzle electrode and the power supply when the resistance outflow path R _N is present across the ground nozzle surface.

Consider the example of a 5 megohm current limiting resistor R connected between a 1 kV unregulated power supply and a contaminating nozzle having a 1 megohm resistance outflow path R _N of ground from the electrode along the contaminated nozzle surface. In the case of a conventional voltage divider circuit, the voltage of the power supply is divided at the electrode and reduces the electrode voltage (V _e ) and the internal induced charge field to one-sixth of the voltage of the nozzle with a very clean surface and no outflow circuit. In another example, for R = R _N , the effective charge voltage is halved. This simple example illustrates that the nozzle charging component must maintain an outgoing ground resistance of significantly higher magnitude than a properly sized power supply current limiting resistor if the resistor is used effectively. The first advantages of the high output impedance system are: safety, longer nozzle life, increased operation reliability even with poorly maintained nozzles, constant spray charge over a wide range of liquid conductivity, use of relatively low voltage, very small power supplies, single It is possible to operate a plurality of charged nozzles with a power source.

Cyckles attempts to maintain a high resistance path between the electrode of the nozzle and ground by using a second air stream designed to prevent the charge spray from returning to the nozzle body. However, the volume of pressurized air used for the second air stream may not be used for large multi-nozzle systems such as 30-80 nozzle crop sprayers used for crop processing. The device must be as compact as possible in order to be used in an air compressor or blower. Excessive pneumatic energy applied to the target is often undesirable, as the electrostatic electric field becomes weaker than the aerodynamic forces, resulting in deterioration and overspray of electrical attachment. In addition, nozzles operating in severe environments of this type tend to trap dust in conductive air and overspray on surfaces even when the second air is used to move contaminants out of the nozzle.

Neutralization of the charged spray droplet group by ionizing the liquid accumulated on the nozzle front

The group of charged spray droplets discharged from the orifice of the induction nozzle creates a strong electric field ending at the target point, nozzle front and other sprayer components. The electric field imparted by the space charge of the nozzle creates a strong attraction between the nozzle surface and the charged droplets. Conventional induction nozzles, such as low nozzles using pneumatic spraying, have the advantage of a gas carrier that effectively drives the majority of the spray out of the nozzle front. Within the spray droplet group itself, the droplets repel each other, and some droplets on the outside periphery deviate from the suction of the gas injection. However, charged droplets that have not traveled a sufficient distance to escape the gas carrier injection and out of the electric field in front of the nozzle return to the nozzle surface along the electric field line imparted by the space charge electric field. This relatively small charged spray that returns to the nozzle causes significant surface contamination and eventually creates a current problem. Another detrimental result is that spray liquid that is drawn back to the nozzles tends to accumulate on the flat face of conventionally charged nozzles. This accumulation can cause partial neutralization of the charged spray. When the adherent liquid begins to fall off the outer nozzle surface, it is pulled toward the spray droplet group by the force of the electric field of the spray droplet group. The accumulating liquid forms a sharp peak and aligns with the electric field. The strength of the electric field at the peak is sufficient to cause dielectric breakdown of the surrounding air. As a result, the electrical charge of air sends ionic charges of opposite polarity to the spray droplet group, resulting in an electrical neutralization of the actual spray portion. In addition, surface accumulating liquids that either electrically escape from the nozzle or drop by gravity cause deterioration of adhesion from discarded and improperly sprayed sprays. Droplets falling off the front of the nozzle are usually substantial and are charged opposite to the spray. Otherwise, in the paint sprayer, this large droplet damages the uniform surface film. In the spraying of insecticides on plants, the attachment of these large droplets can cause severe plant fiber damage where the overdose adhesion occurs.

The shape of a conventional parmenta nozzle reduces the ionization points formed from the surface film of the nozzle orifice zone by recessing the outlet of the cup-shaped cavity with the outer rim towards the spray droplet group. However, ionization and dropping occur at other surfaces of the nozzle when the nozzle surfaces are sufficiently wetted. The charged droplets returning to the nozzle are attracted to the rim edges because the field lines are concentrated on the rim edges of the cavity. This helps to limit the amount of spray that coats behind the body of the rim edges, but the collection droplets build up and coarsen in the edges themselves. Prior to dropping, the liquid tends to be pulled towards the spray droplet group, resulting in a sharp peak in which charge opposite to the spray droplet group is released and neutralizing much of the charged spray droplet group. In addition, the parmenta nozzle is formed integrally with a large radius flange around the nozzle. This flange serves to lengthen the insulating surface and prevent the returning charged spray from coating the top of the nozzle body. However, eventually the front and edge surfaces are coated towards the spray droplet group to form the dropping point of the multi-ion tendency. In addition, the cup-shaped cavity in front of the nozzle prevents the nozzle from facing upstream and is used, because the cavity tends to fill with liquid that accumulates on the rim edge and drips into the cavity, ultimately partially orifice Emitted as a large liquid slug that blocks or very severely degrades the spray adhesion.

In addition, all products of conventional low nozzles exhibit problems with dropping and spray droplet neutralization, particularly in recent products where a flat surface cover is mounted on the smaller flat front of the electrode top for protection. Compared to the parmenta nozzle, the row nozzle tends to collect less liquid because the cover front is less than half the size. However, a group of accumulated droplets falling from the lowest edge of the front is sufficient to cause the formation of peaks of prominent ionization tendency.

Mechanical wear of the spray channel

Another limitation in conventional inductively charged nozzles is the tendency for the spray channels and spray outlets to wear quickly under normal use by spraying comprising abrasive material. Narrow spray forms and air barriers generated between the spray and channel walls by the low nozzles somewhat limit abrasive wear, but at this time the atomization channels are electrically conductive such as induction ionization from the liquid orifice tip and current tracking along the inner wall of the spray zone. It is slightly deformed by spray adhesion, which impairs shape from action and leaves it from improper cleaning. The deformation breaks down the narrow spray form, and some air driven sprays impinge on the plastic wall near the outlet and wear out the wall. Indeed, the discharge portion of the nozzle wears down twice the initial diameter for a period of only half a day while spraying certain abrasive materials such as diatomaceous earth or sodium aluminofluoride. Even without involving this action, the electrode will also begin to wear, starting at the discharge end and running backwards. Air consumption, spray charge and spray properties are all adversely affected by abrasive wear.

FIELD OF THE INVENTION The present invention generally relates to electrostatic spray devices, and more particularly to pneumatic sprays, hydraulic sprays and other types of inductively charged spray systems.

1 is a perspective view of an assembled first embodiment of an induction spray charged nozzle according to the present invention;

2 is a perspective view of an assembled first embodiment of an induction spray charged nozzle according to the present invention;

3 is a cross sectional view of a first embodiment of an induction spray charged nozzle according to the invention;

4 is a detailed perspective view of a twin fluid tip of an induction spray charged nozzle embodiment according to the present invention in which an air channel is used to direct air into the spray zone.

5 is a cross sectional elevation view of a second embodiment of an induction spray charged nozzle according to the present invention including a hood;

6 is a perspective view of a third embodiment of a nozzle system according to the present invention;

7 shows the drawn air flow region and electric field imparted on a nozzle according to a preferred embodiment of the present invention.

8 shows the field and the suctioned air flow region imparted on a nozzle according to the invention with a hood mounted on a cavity for creating an increased curved electric field for the mechanical shielding of the surface and the exclusion of charged particles. .

9 shows a fourth embodiment of an inductively charged nozzle according to the invention in which a resistive element is mounted in the nozzle between the power outlet and the nozzle electrode.

FIG. 10 is an inverse numerical graph of ground electrode resistance measured during a time interval for spraying a common high conductivity crop mixture by comparing a nozzle according to the present invention with a conventional nozzle. FIG.

11 is a graph showing the degree of charge obtained over time for a nozzle according to the present invention as compared to a conventional nozzle.

12 is an inverse numerical graph of typical power supply current required over a half day length of time for operating a nozzle according to the present invention as compared to a conventional nozzle.

FIG. 13 is a schematic representation of a spray charged nozzle system with a resistor inserted between a power supply and a nozzle having a contamination resistant surface. FIG.

The present invention provides an improved electrostatic spray charged nozzle for safe spray charging with a wide range of spray liquids comprising relatively high material concentrations of relatively abrasive powders, metal elements, corrosive materials and / or highly conductive materials. It is also safer and more reliable in environments where nozzle surfaces are contaminated by sprays and other materials, nozzles are easily operated by inexperienced operators, and nozzle maintenance is ignored. The system also provides nozzles that require low voltage, enabling the operation of many electrostatic spray nozzles with a single small power source and operating a single nozzle with a very small power source that can be embedded within the nozzle if desired.

The pneumatic atomization inductively charged nozzle system according to the present invention comprises, among other methods: (a) a group of spray droplets originating externally in the nozzle and the electrical insulation and internal charge field of the liquid stream from internal and external current outflows; Forming an electrical barrier between the zones to maintain a stable internal electrostatic charged field between the liquid jet and the induction electrode, (b) to maintain the nozzle surface potential to prevent discharge of charge on the internal and external nozzle surfaces, and (c) the ground jet. By spray neutralization by creating high electrical resistance between the high voltage power supply and the spray nozzle electrode, (d) using abrasion resistant material at the nozzle outlet, and (e) outer surface geometry of the nozzle to minimize nozzle coating and space charge induced ionization The technique has been improved.

The nozzle assembly according to the invention comprises a body terminated in a twin fluid tip seated on a cover comprising a pneumatic spray chamber and a charged electrode. The liquid jet is maintained at or near ground potential and grounded at an appropriate upstream position. The charge is induced and flows into the liquid and is concentrated on the surface of the liquid jet which enters the spray zone corresponding to the electric field at the spray surface. The droplets are formed by pneumatic energy that causes the charged spray to escape from the electrode region towards the target point through nozzle spraying.

According to one aspect of the invention, the nozzle assembly consists of a body terminated in a twin fluid tip detachably connected to the cover. The cover has an outer surface of conical or other aerodynamic shape that terminates in the spray injection outlet. The cover has an internal electrode forming a spray channel and comprising an induction electrode. The body and cover can be easily separated to access all areas that do not need to be cleaned periodically and include air channels, liquid channels, liquid orifice tips, atomization channels, charged electrode surfaces and air plenum areas. The liquid orifice tip, electrode and other internal nozzle component need not be integrally separated from the body or cover. Therefore, the components are not affected by misalignment or contamination during reassembly, disassembly or operation.

According to another feature of the invention, the electrical connection of the power supply and the electrode is disturbed when the cover is loose or detached. This reduces the likelihood that an operator will inadvertently connect with the power source when irradiating or cleaning an electrode or other portion of the spray zone. This feature also precludes adjusting and modifying any fragile wires while cleaning spray channels or other zones.

Some features of the nozzle according to the present invention include the elimination of drift current across the contaminating surface film that forms at any time on the internal dielectric surface of the inductively charged nozzle, such as the surface of the liquid orifice tip and the area around the spray chamber. On the inner surface of the nozzle according to the invention, the same potential surface is intentionally retained in the region of the cover adjacent and upstream of the electrode. The gas plenum, seal and spray channel, which are inside the cover assembly, are located between the electrode and the conductive or semiconducting annulus at similar potentials to the electrode. This equalizes the voltage on the dielectric surface, resulting in a conductive contaminant film on the surface, which causes current to travel backward from the electrode toward the low potential body of the assembly and damage to the electrical tracking path on this major interior nozzle area. It prevents it from forming. In addition, the inner conductive annulus is convenient for making electrical connections independent of alignment from the power conduit of the body to the electrodes of the cover. Another advantage of the internally charged annular surface is that the surface inherently creates an electrical barrier, such as that added by the spray droplet group space charge, which will pressurize the charged field on the opposite side of the spray charged field of the nozzle. It is added between the existing electric field which exists.

The liquid channel, liquid inlet connection and liquid tip are contained within the low voltage body. The liquid is grounded at a predetermined portion upstream of the liquid orifice, such that the parallel resistance of the stream portion between the ground and the electrode and its seamless conduit creates a potential for liquid injection in the orifice, resulting in a ground short circuit and the total short circuit during normal operation. Float between electrode voltages during conditions. In the case of a direct short circuit generated by a conductive fouling connection between the liquid orifice tip and the electrode, a current short occurs through the material connection where it is generated and through the resistive liquid stream and its conduit. The liquid between the tip and the upstream ground of the tip forms a resistor, and the self limiting current and subsequent limiting damage the nozzle component. In addition, damage is prevented because the nozzle liquid flow stops because the current stops when the liquid is discontinuously connected, as the liquid evaporates from the channel of the liquid orifice tip.

In addition, the possibility of a short circuit of the liquid orifice tip is limited by the spray gas traveling in the plenum surrounding the base of the tip and the ultrafast gas pressurized into the atomization zone surrounding the liquid orifice tip. In order to prevent additional safety and an electrical short circuit between the electrode and the liquid orifice tip, which is liable to occur in the absence of atomizing gas flowing through the atomization channel, the electrode voltage is preferably not connected to the power supply by pressure switch regulation.

Another feature of the present invention is to significantly reduce the drift current on the nozzle outer surface compared to conventional nozzles operating in situations where the nozzle surface is contaminated. When the fouling film is formed at any time on the outer dielectric surface of the electrostatic spray nozzle, the surface adjacent the electrode downstream of the electrode is then sufficiently conductive to electrically connect the electrode to the grounding component of the sprayer. The resulting stray surface currents create defects that eventually destroy the dielectric surface, electrode surface, fluid connections and wires of conventional spray charged nozzles. The main feature of the present invention is to maintain a high resistance path from the electrode to the ground, whereby it is attached along the inner wall of the spray channel in the rear of the twin fluid tip direction and in front of the outside front of the nozzle and to the ground of the sprayer. Prevents significant charge from flowing out of the electrode along the contaminated external dielectric surface. High resistance paths are created because the selector on the nozzle surface is protected from contamination. A method of maintaining a high impedance path is to properly form a cavity into a selected nozzle surface or on an electrical isolator used to connect the nozzle to a ground sprayer, which prevents contaminants from entering the interior of the cavity. will be. Preventing contaminants from penetrating into the cavity is provided by aerodynamic, sonic, thermal, electrical, mechanical, or other forms of energy inputs, or existing electric, applied electric fields, and gaseous flow areas in the vicinity. It can be prepared manually by appropriately forming a cavity in order to prevent contaminant ingress by interaction with the. In a preferred embodiment of the invention, the aerodynamic shape of the nozzle aims to form a generally thin layer flow on the nozzle surface in order to reduce the tendency of attracted particles to adhere to the nozzle surface, but such as a rim or edge Certain carefully located electric field concentrators create electric field regions of strength that tend to repel or deflect the particles.

In one embodiment according to the invention, the dielectric nozzle body in which the gas, liquid and electrical terminals are located and the mounting connection is electrically insulated from the cover portion by a protective cavity formed into the body. Therefore, the outer body cover is maintained near ground by the conductivity of the contaminated body surface, and perceptible current flow across the body surface from the high voltage component of the nozzle is prevented by the resistance inside the protective cavity. In addition, the preferred embodiment has a protective cover surface of the nozzle assembly that includes the internal electrode. In addition, this protective cavity isolates the ground electrode in the event of a surface defect, and raises and maintains the spray channel and other outer cover surface at a voltage similar to that of the electrode voltage, thereby crossing all surfaces adjacent to the electrode. Prevents charge flow from the electrode.

The potential applied to the outer surface of the cover is opposite in sign to the voltage of the spray droplets, but this does not significantly increase the attractive force of the charged droplets toward the nozzle surface beyond the potential of the ground nozzle surface, and the charged spray impinging on the cover significantly increases the power current. Do not increase. If the clean dielectric surface of the charged nozzle body and the cover is damaged by the conductive fouling film, the nozzle body and the cover have a potential similar to that of the ground mount attachment and the induction electrode. The less current flows from the contaminating surface, the closer each contaminating surface is to the same voltage surface.

The magnitude of the space charge field generated by the negatively charged spray droplet group is measured to be -3 kV / cm or less at a distance of 10-15 cm below the spray injection centerline of the nozzle outlet. Therefore, the space charge potential is near -35 kV relative to the ground nozzle surface and near -36 kV relative to the cover surface rising to the +1 kV electrode voltage. A +1 kV charged cover is preferred to pull the charged spray to the cathode, but the force is approximately only 3% or more relative to a similarly shaped ground surface and to the spray droplet group. When a negatively charged spray is deposited on the charged cover, a neutralization current is generated so that the cover flows from the induction electrode to maintain its potential, but the current required is very small. Assuming 1% of the spray "rolls back" to the nozzle at two-thirds of the cover, a typical 10mA spray droplet current requires only 66nA from the electrode's power source to neutralize the rollback. . In fact, the rollback of the charged spray is almost 1% or less.

The nozzle according to the invention significantly reduces particle adhesion on the selected nozzle surface by means of a charged spray rollback and a suitable shape outside the nozzle. The nozzle shape forms a surrounding air flow region, creates a useful electric field shape from the near potential of the group of charged spray droplets, and generates a strategically curved electric field form between defective dielectric surfaces where the potential is intentionally maintained.

Charged droplets that return to the front of the spray nozzles and cause neutralization of the spray droplet group and electrical tracking are problems encountered in all conventional commercial products of low devices and other inductive charge nozzles. This is because the devices have a generally flat, frontal surface perpendicular to the axis of the gas jet in which the droplets are seated. Liquid adhesion is particularly severe in situations where the nozzles are sprayed upwards or horizontally, or in situations where oppositely charged nozzles are sprayed against each other, such as in a vineyard injector.

In order to reduce spray adhesion onto the nozzles of the present invention, the surface finish is smooth and generally conical or mechanodynamic in shape, preferably tapered forward as narrow as possible to the ejection outlet. This conical front taper terminating at a high speed jet produces a significant amount of ambient air suction. Aspirated ambient air flows across the outside of the smooth nozzle to the juice spray jets, creating an air "curtain" across the holes in the cavity and helping to prevent particle entry. In addition, the air flow across the nozzle surface helps to prevent contaminants from adhering and directs particles and spray droplets towards the target point. The predetermined volume of gas sucked is added to the outer layer of the main gas injector discharged from the nozzle. This added gas flow tends to repel the droplets more slowly around the outer periphery of the spray droplet group in the intended direction of exit from the nozzle, and the power of the overload causes the rollback of the droplets. In a nozzle with a flat front face, surrounding droplets tend to return and adhere at any time onto the nozzle surface.

In order to further reduce spray deposition and liquid accumulation of the nozzle according to the invention, an electric field line by the potential of the spray droplet group is generated and attached to the nozzle front end closest to the main gas / spray jet. The tapered shape forward of the cover reduces the area of attachment surface proximate to the group of charged spray droplets, and the increased curvature at the discharge ends most of the electric field on the conductive membrane surface around the spray jet. Therefore, it is desirable that the charged droplets returning to the nozzle are attracted toward the attachment surface region of sharp curvature, and since the air flow region is most attached to this region, all droplets approaching this region attach at the nozzle surface. And are reabsorbed into the main gas / spray jet before discharge. A small amount of liquid adhering to the surface near the jet outlet may be immediately drawn into the main gas / spray jet by a strong venturi action, resprayed before dropping, and then induced ionization may occur. Although the influence of the spray droplet group electric field is weaker by the distance from the liquid droplet group and by the continuous smooth shape, certain liquid spray materials are attached on the upstream surface of the conical cover. If the liquid is not dripped or accumulated sufficiently to start induction ionization, it is because the liquid is steadily drawn into the main injection section by the air around the shielding film which is sucked toward the flow of the main gas injection section of the nozzle.

Imparted by a method of mechanical exclusion to shield the interior of the cavity and the previously described air curtain generated across the cavity and the nozzle surface by ambient air sucked by pressurized gas jets present at the front end of the nozzle In addition to the shielding provided, another shielding from entry by the charge spray is obtained by an electric field suitably formed at the cavity inlet, causing the charge spray to repel to escape from the hole. As previously described, the nearby charge spray droplet group adds an electric field of "space-charge" force on the order of 2-3 kV / cm that drives the charged droplet from the area of the charged spray droplet group toward the intended ground target. This space charge electric field also generates an electric field terminating on the nozzle itself. The energy of the gas carrier is sufficient to propel almost all the spray away from the nozzle, but some travel along this field line toward the nozzle surface. This space charge electric field terminates vertically on the conductive fouling nozzle surface. In addition to the electric field imparted by the presence of a group of charged spray droplets, a strong electric field is also present between the high voltage cover of the nozzle according to the invention and the low voltage body surface. These two electric fields are complementary in the direction of flow. On flat surfaces, the field lines are evenly spaced, but at discontinuous surfaces the field lines are more concentrated. One feature of the present invention is to locate discontinuous or field line concentrators on the nozzle surface to concentrate the intensity of the electric field and provide a curved field line resulting from the potential of the spray droplet group and the potential intentionally held on the nozzle surface. Cause Charged spray droplets approaching the curve's field line are subjected to strong centrifugal forces, pushed outwardly from the cavity opening, into the surrounding air flow zone, and re-absorbed into the juice spray droplet group directed towards the target point.

In a preferred embodiment of the invention, the outer surface of the cover is generally in the shape of a cone that converges forward and surrounds the spraying and charging zones. The cover surface is preferably made of a dielectric material and is sufficiently soiled and somewhat conductive when exposed to a spraying environment. Therefore, advantageous field boundaries are maintained, effectively surrounding the internal charge induction system and effectively separating the system from the opposing space charge field created by the presence of a high charge spray discharged from the nozzle outlet.

The shielded cavity interior surface of the nozzle according to the invention described above results in a high resistance between the electrode power supply of the nozzle and the ground, which significantly reduces the current of the power supply compared to conventional nozzles. The high impedance prevents the successful supply of a series of shielded resistance elements with nozzles between the power supply and the inductively charged electrode without a significant voltage drop at the electrode. In a preferred embodiment of the invention, this resistive element must be included in the nozzle itself. The component in which the power source is mounted in the nozzle simply has a resistor at the power outlet. If multiple nozzles are connected to distant power supplies, the resistors are located at the power supply in addition to the individual resistance elements in the nozzle. Alternatively, the multiple discharge resistors can be located within the power supply itself with direct connection to the nozzles. In addition, a resistance wire is used to achieve the above object. If multiple nozzles are connected to a single power source, it is desirable to use discharge resistors for each nozzle to prevent shortened nozzles from affecting other parts.

One of the advantages of the resistance conduit between the power outlet and the electrode of the high impedance nozzle is safety. The system is designed so that there is no shock around when operating a powered nozzle. Another advantage found due to the series resistors used in conjunction with the high impedance nozzles is that the induced electric ionization of the liquid jet and thereby the resulting power current and the resulting ion current from the induction electrode are significantly reduced. If the electrode is wet or has exposed edges or other discontinuities, the ion current has been noted in conventional nozzles.

The high impedance properties of the nozzles according to the invention allow the power source to be successfully placed on or in the nozzle. The reduced supply current and voltage not only allows the use of very compact DC-to-DC converters that can be conveniently mounted in the nozzle or closed within the nozzle, but low voltage leads or batteries connected to the power converter originate from the electrodes. Can be shielded from damage by electrical tracking. In previous configurations, such as the development of Raw, in which a power source was attached to or included in the nozzle, the low voltage lead was drawn from the nozzle surface from the contamination electrode and subject to voltage and current. If a power source is mounted on the nozzle or embedded in a portion of the nozzle, the preferred embodiment includes a low voltage input wire or connection that projects from the low voltage portion of the high impedance nozzle as disclosed herein. This prevents the coating layer of contaminating material from reaching the potential near the electrode voltage on the outer surface of the insulator surrounding the wire insulator or connector, resulting in electrical breakdown of the insulator. The power supply itself can be mounted to the high voltage portion with the low voltage input conductor shielded from contamination by placing the conductor in the low voltage nozzle portion.

Another major feature of the nozzle according to the invention is the use of a strong, wear resistant material which is integrated into the atomization channel which prevents early electrical or mechanical etching of the channel. In a preferred embodiment, the ceramic is selected for wear resistance and electrical insulation. Electrically conductive ceramics of any shape may be used as the electrode material. The wear resistant electrode forms part of the walls of the atomization channel or constitutes the entire channel surface.

In a preferred embodiment of the invention, the channel of the atomization zone is a straight hole deviating from the spray outlet, as opposed to a converging channel which has been used in the existing configuration and can cause the loading of material in the channel or spray outlet.

In addition to these objects, features, and advantages of the present invention, other such objects, features, advantages, and advantages of the present invention will become apparent with reference to the remainder of the specification.

1 shows one form of a preferred embodiment of an inductively charged nozzle according to the invention. In this embodiment, the nozzle largely consists of the main body 1 and the cover 2. The liquid inlet 8, the gas inlet 7 and the power input 9 are located at the back of the main body 1. Charged spray in the gas carrier 15 is discharged from the front end of the nozzle through the outlet 33. The conical cover 2 of the nozzle is tapered towards the outlet front 24. The hood 30 is shown as being located on the body 1 of the nozzle. With reference to FIG. 2 showing an unassembled embodiment, it is preferred that the cover 2 can be detached at any time from the body 1 exposing the inner region for operation. The cover 2 is preferably fixed firmly on the body 1, which consists of a thread 3, i.e. a screw, a latch or other attachment means, which can be easily removed, which means that the novice is injured. It is possible to dismantle for inspection, cleaning and reassembly without misalignment or misalignment, and it is preferable not to use a general tool, but a general tool may be used. The downstream end of the body is formed of a twin fluid tip 12 comprising a gas outlet 21 and a plenum 13 and a liquid orifice tip 16. Electrical connection with the power source is made via a connecting terminal 23 that engages with the annular induction surface 19 shown in FIG.

Referring again to FIG. 3, where a cross-sectional view of a nozzle in accordance with a preferred embodiment of the present invention is shown, the nozzle body 1 is preferably molded from a dielectric material, with low surface wettability, low surface and volume conductivity, low adhesion. It is preferable to have. The main body 1 includes a gas 4, a liquid 5 and an electrical conduit (not shown in FIG. 3, but with reference to FIG. 9). The gas 7, the liquid 8, and the inlet for power (see reference numeral 9 in FIG. 1) are preferably located at the rear face 10 of the main body 1 farthest from the front face 24 of the nozzle. If desired, the gas inlet 7 can be adjusted to the filter screen 11.

The fluid conduits 4, 5 as well as the electrical conduits are generally shaped to continuously pass through the nozzle body 1 without seam or disconnection of the body. However, in some cases it is desirable to press or mount the liquid orifice tip 16 into the body 1, in which case it is desirable to manufacture the tip 16 itself from a different material, such as ceramic, or It is desirable to make 16) periodically replaceable. It is not desirable to use seams that can be contaminated and expose liquid to the induction electrode bolt through drift current on the nozzle surface. In certain cases, it may be desirable for the power source to be contained within or attached to the nozzle body 1, thereby eliminating the high voltage line from outside the body 1.

The body terminates with a twin fluid tip 12 as shown in FIG. 2 and slightly modified in FIG. 4. As shown in FIG. 3, the gas conduit 4 penetrating the body 1 terminates at the outlet 21 with a plenum 13 surrounding the base of the twin fluid tip 12. The outer rim 22 of the plenum 13 serves to seal the cover 2 against the base of the plenum 26. An additional seal may be provided by the flexible seal 17 against the rim 25 formed inside the cover 2. These seals serve to prevent gas outflow and to limit the current passageway on the inner surface. Gas pressurized from the plenum 13 may flow through multiple ports 14 surrounding the base 34 of the twin fluid tip, as shown in FIG. 4, or FIGS. 2 and 3, and the twin fluid tip The base 34 of 12 is narrower and smoother to allow gas to flow completely around the periphery of the base 34. The smoothness is desirable for maximum electrical insulation of the fluid tip 12. However, if a gas channel is needed in the zone to direct air flow, then the slotted channel 14 is more preferably a hole, where the side wall surface of the slot is exposed when the cover 2 is removed. This is because the side wall surface can be cleaned more easily than the inside of the hool. This slot may be in the axial direction of the spray airflow 15, or the slot 14 may be at an angle (as shown in FIG. 4) if it is desired that the radial motion of the exhaust gas make a wider spray angle. Can be formed.

The liquid conduit 5 ends with the outlet of the liquid orifice tip 16. In general, as shown in FIG. 3, the orifice tip 16 is preferably disposed upstream from the electrode 18. However, it has been found that the position of the tip 16 can be varied to obtain the desired atomization and chargeability and to change the liquid flow rate.

Referring again to FIG. 3, a gas plenum 26 surrounding the base 34 of the twin fluid tip 12 is formed inside the front end of the cover 2 of the nozzle. The gas plenum 26 serves to uniformly accelerate and direct the flow of pressurized gas into the atomization zone, thereby forming part of the wall of the atomization channel 35. The shape of the plenum 26 is shown as a generally frustum that transitions into a cylindrical shape, although this shape is suitable for narrowly oriented sprays, other structures can be used to result in a modified spray form. A gas plenum 26 located around the base of the tip 12 helps to keep the zone free of severe contamination while the plenum 26 is pressurized. When the gas pressure is removed, the spray liquid falls into the atomization zone 35 and the plenum region 26, which is why it is desirable to use a simple pressure transducer to control the electrode power source. In addition, arcing between the electrodes 18 can cause a lack of gas flow in the tip 16. It is also preferred that the gas pressure is maintained for a short time after the liquid flow is stopped to remove residual liquid by venturi action at the tip 16.

In a preferred embodiment of the invention, the conductive induction electrode 18 is suitably positioned such that the inner surface of the electrode forms part of the wall of the atomization channel 35, which is located downstream from the liquid orifice tip 16. It is preferable. The atomization channel injection outlet 33 which serves to direct the spray injection and to cover the front edge of the electrode 35 is preferably in front of the electrode, ie downstream. If it is necessary that there is no injection outlet 33, it is preferable to be molded of a wear resistant material such as ceramic. The outlet 33 need not be a non-conductive, poorly conductive material, such as stainless steel, although the insulation is desirable for personal safety. Prior art inductively charged nozzles tend to wear or degrade the spray outlet zone when the atomizing liquid contains abrasive powder or coarse chemical. The nozzle according to the invention preferably incorporates a spray outlet shaped as a ceramic material. It is common for ceramics of the alumina industry to be selected for this purpose because of their resistance to abrasion and deterioration by acidic solutions, alkaline solutions, salts and solvents. Alumina ceramics exhibit strengths that surpass almost all other materials. In addition, these shaped ceramics exhibit high dielectric strength, high surface resistivity, low surface wettability and low porosity. The ceramic form may be molded using standard ceramic portion forming techniques. Certain alumina ceramics of the type containing glass-bonded mica, such as "MACOR" from Corning, are particularly suitable for forming the jet outlet 33 by standard processing methods. Other materials suitable for this application include wear resistant plastic materials. These materials contain carbon fibers that impart electrical conductivity to plastics. With this material, the components forming the walls of the atomization zone, such as the electrode 18 and the spray outlet 33, can be formed in one piece. This solves the problem of embedding the metal electrode and greatly simplifies the manufacture and design of the nozzle.

The main concepts of this electrostatic spray system include maintaining the surface energy on the selected nozzle component and maintaining a high resistance path of ground at the electrode 18. The main advantages of the present invention include tracking surface currents, reducing induced ionization at the nozzle front, reducing power source size and emissions, and improving stability. In order to eliminate surface charge flow, the outer and inner nozzle surfaces that contact the electrodes 18 through surface contaminants are maintained at a similar voltage as the electrodes 18. The main body 1 of the nozzle is sufficiently insulated from the cover 2, so that even if the rear base surface 10 is contaminated, the base surface 10 is a ground spray to which the flow connecting parts 7 and 8 and the main body 1 are eventually connected. It is in a state of almost ground voltage with minimal current flowing into the rear portion.

The method of obtaining a high electrical resistance between the electrode 18 of the nozzle and the ground consists of physically shielding the nozzle surface selected from other contamination or spray contamination that adheres to the nozzle and forms a drift current path. 2 and 3 show an example of an additional current limiting cavity 29 formed of a cover 2 and a current limiting cavity 28 formed in the body 1. These cavities 28 and 29 may take an annular or any other desired shape, creating a zone that is partially shielded from sprays or other contaminants, preserving high resistive surfaces. Charged spray that returns to the nozzle when driven on an electric field line loses enough kinetic energy to pass through the cavity depth at any time and attaches best on the cavity edge where the field line is concentrated. If a spray substance or other liquid eventually adheres inside the cavities 28 and 29, the amount is always small, and the liquid does not accumulate to form a continuous path, and the liquid film is better than having a separate small liquid droplet attached. It shows conductivity. The cavities 28 and 29 can be cleaned periodically and can be easily accessed when the body 1 and cover 2 are separated.

When the nozzle is operated under certain stringent conditions, the gas injection portion 40 (not shown in FIG. 3) is directed to the cavities 28 and 29 to clean the interior of the cavity continuously or periodically. For example, when atomizing gas supply is not considered, a predetermined amount of gas is directed through several small diameter holes 40 drilled radially or slightly tangentially out of the gas supply pipe 4, which The gas supply pipe 4 produces an activating gas that sweeps the pressure gradient and the body cavity 28 to prevent particle adhesion therein.

Another shielding from surface contamination inside the cavity is provided by the addition of a shield for the mechanical protective film and to produce an electric field of a form which is advantageous for preventing the entry of charged liquid droplets. One example of such a shield is shown in the cross-sectional view of FIG. 5 (although other structures and shapes can be used). In addition, this outer shielding film in the form of a hood 30 shields the nozzle outer surface, the nozzle body cavity 28 and the surface of the cavity 29 of the cover. The hood 30 may be positioned as shown for downward nozzle clogging, or may be fitted back to the cover of the seat 31 for upward nozzle clogging. In addition, another shield may be added with the placement of an annular disk shaped dielectric barrier 32 located between the body and the cover. In addition, the barrier 32 covers the cavities 28 and 29, producing a non-smoothness of the surface that limits or deflects the ingress and surface adhesion of charged sprays or other contaminants that float in the air flow around the nozzles. do. The outer larynx 30 and the inner barrier 32 can be made integrally with the nozzle body or can be made separately, with dielectric materials of low surface wettability, low volume and surface conductivity and low surface adhesion properties such as UHMW or PTFE. It is preferred to be molded.

Another shielding membrane configuration is shown in FIG. 6 to preserve the high resistance path between the electrode 18 of the nozzle and ground. In this embodiment of the present invention, the basic hood shaped shield 36 is located between the charged nozzle 38 and the ground spray portion 39. In this embodiment, the dielectric isolator structure 37 is a gas and / or liquid line entering the back side 10 of the nozzle. The shielding film 36 mechanically shields the dielectric isolator support 37 from contamination. It is also advantageous to change the electric field to prevent the adhesion of charged droplets on the inside of the shielding film.

Additional hoods, cavities or other shielding methods can be added to the nozzle body, cover, nozzle mount, tubing or wires that are placed up and down with each other to form a maze, or are added and / or formed if greater insulation is required. have. Often the perforated outer shield provides a shield from electrical attachment on the inner surface that allows the accumulated liquid (or rain) to escape.

According to the present invention, the nozzle surface affects the shape and concentration of the space charge field lines placed on the various body 1 and cover 2 surfaces in order to have a favorable effect on the trajectory of the charged spray liquid droplets returning to the nozzle. It is formed to. A group of suitably charged spray droplets discharged from the inductive charge nozzle add an inert space electric field of 2-4 kV / cm to the flat nozzle surface. On the contaminant-inducing surface of the nozzle, which is smooth and smoothly continuous, the space electric field ends evenly spaced and vertically terminated. Because of the discontinuity of the angular surface, the field line still terminates vertically, but is more concentrated in the convex shape and less concentrated inside the concave shape. In the case of the nozzle according to the invention, the potential is maintained in the nozzle surface thin film, and the cavity edge and other nozzle surfaces are intentionally formed such that a curved active field is added to shield the nozzle surface from charged spray attachment. Charged droplets traveling along the electric field line of the curve effectively repel the droplets from the cavity area, separating them from the nozzles and sending them to the airflow region, thus influencing a strong centrifugal force that shields the region from the attachment of liquid droplets. Receives.

In the embodiment shown in FIG. 7, the formation of the surface contaminant system on the body 1 attached to the ground sprayer eventually becomes the ground surface of the body 1. The surface 50 of each of the covers 2 carries a potential near the surface of the electrode 18. This results in an electric field in the space separating the two parts of the surface 50. In the embodiment shown in FIG. 7, the field line concentrates on the rims 54, 55 of each of the opposing cavities 28, 29, producing a strong curved electric field as shown. Charged droplets returning to the nozzle along the space charge electric field originating from the spray droplet group are prevented from entering the cavity because when the droplets are attracted to the electric field of the curve of increasing strength, the droplets are accelerated and The centrifugal force dislodges liquid droplets from the sharp curved path of the electric field and transfers them to the suction air flow region 61 surrounding the spray nozzle.

The air flow region 61 and the activating electric field 60 work in concert, and each of the flow region 61 and the electric field 60 moves a drop of charged liquid liquid in the direction of the intended spray target. While the negatively charged liquid droplets occurring at the positive electrode's induction electrode are used for the purposes of this embodiment, the resultant direction of the liquid droplets moving in the curved electric field as a result is the same despite the multiple induction electrodes.

Referring to FIG. 8, a very strong curve across the entry path between the hood rim 56 and the edge 57 formed on the nozzle cover 2 by adding a suitably formed hood 30 on the cavity hole. Generates an electric field 62 of. A typical 800V anode potential on the surface thin film of dielectric cover 2 located 1/2 cm from the ground plane will produce a straight field of 1.6 kV / cm. In the case where a sharp contour is strategically formed on the body opposite the sharp lip of the ground hood, the electric field shape is curved and the electric field strength is not desired because the resulting ion current is added to the power supply demand, If desired, it can be made to approach the dielectric collapse strength of air. The strength of the electric field is somewhat necessary to generate centrifugal forces that repel 30 mm droplets of charge charged at around -5 mC / kg. Under stringent conditions, when liquid accumulates on the hood 30 or on the back side of the body 1, the liquid moves to the hood rim 56 and before the formation of a drip point of ionization tendency, It is drawn to the system 62. The liquid tends to be attracted to the cover 2 while avoiding the cavities 28 and 29 along a curved line, which is drawn to the jet by the venturi action and re-sprayed.

The cavity edges 54 and 55 use an electric field that remains active between the nozzle and the cavity edge while forming an electric field to increase the repulsion of liquid droplets from the shielded surface portion. Conversely, the front end 58 of the nozzle is shaped to draw liquid droplets from the outlet 33 toward the front 24 while using an inactive electric field 63 formed by a nearby group of charged spray droplets. The sharp convex shape at the front end 58 of the nozzle and its proximity to the group of spray droplets charged at this surface create a strong concentration of the electric field around the front of the outlet 24. The charged liquid droplets move towards the nozzle front end 58 and the majority reenter the spray jet and are driven towards the target before impacting the nozzle. The adhering spray liquid is dragged along the surface 50 and resprayed into the sprayer portion by a strong venturi action.

High speed gas spray injection is used to repel or discharge charged or uncharged sprays that tend to collect on the nozzle surface. Spray gas injection of locally high kinetic energy and speed may be achieved by a small front region of the wear resistant outlet 33, the front of the outlet 24, or when the gas and the attached charged droplets are discharged through the injection outlet 33. It produces a pressure reducing zone that draws any spray into the spray which tends to adhere or accumulate on the other surface 50 of the cover 2. By following the law of conservation of momentum, molecular collisions of the high velocity central gas jet exiting the nozzle of the forward jet outlet 33 impart a velocity and draw a significant volume of ambient surrounding air. The suction accelerates an additional volume of air into the high velocity gas / spray main injection discharged from the nozzle along the outer surfaces of the nozzle body 1 and the cover 2. The controlled air movement along the nozzle surface of a suitable contour is advantageous for the shearing force that separates the adhered liquid before the liquid has accumulated sufficiently to initiate an induced electric discharge peak. In addition, small airborne spray droplets and other contaminating particles that accidentally diffuse into the shielding cavity will escape by vacuum or venturi action, similar to tobacco smoke coming out of the interior of a vehicle running through a slightly open window.

The present invention provides centrifugal forces on charged particles moving in a curved electric field that works in conjunction with an aerodynamic flow region to rule out excessive liquid accumulation, droplet discharge due to adhesion, and induced corona and liquid slugging problems observed with conventional charge nozzles. It relates to the external shape of the nozzle body and the appearance of the attached cover piece to effect the advantageous effect of.

9 shows an elevation view of the cross section through the axis of the electrical conduit 6 terminating at the downstream end of the nozzle body 1 of the connecting post 23. The electrical conduit 6 through the body 1 may comprise a power supply wire, the power supply itself, or may be made of a conductive or semiconducting material connected to the power supply. If the electrode power source 43 is integrally molded to or attached to the nozzle, the preferred embodiment comprises a low voltage input connection 64 of the low voltage body 1 of the nozzle. When the power source 43 is mounted to the cover 2, the low voltage input lead is positioned inside the low voltage nozzle body 1. If it is desired to have a low voltage input lead externally on the high voltage portion of the nozzle, then the lead portion of the high voltage insulator is used, and a shielding hood or other structure is used to shield the lead portion along the wire insulator surface towards the connector or ground sprayer portion. Minimize electrical tracking.

In the embodiment shown in FIG. 9 where a high voltage conductor is inside the tube 6 of the nozzle body 1, the tube 6 is connected with a conductive surface 19 electrically connected to the electrode of the cover 2. The terminal 23 is provided. The conductive surface 19 may be a metal or conductive plastic annulus inserted into the cover cavity or may be a conductive plastic that is poured or poured. The conductive surface is preferably continuous or surrounds the interior of the cover in order to establish an equipotential on the surface thin film of the inner surface 59 of the upstream cover of the electrode 18 with respect to the conductive surface 19 thereof. The equipotential surface 59 prevents the current path from forming from the electrode 18 behind any critical surface of the nozzle spray zone, or prevents damage to the twin fluid tip 12. In the case of a direct circuit between the liquid orifice tip 12 and the electrode 18, the current is directed towards the liquid stream itself instead of following a path on the dielectric surface, and the resistance path of the liquid stream and the resistive element of the electrode input are Limit the overall arc.

An electrical passage 20 is formed in the cover 2 between the conducting surface 19 and the electrode 18. Wire or other high-conductivity, or fixed resistor 41 may be inserted into the passage 20, or the electrical connection may be through a conductive or semiconducting material such as carbon loaded plastic that may be injected or poured. If it is desired to use a resistive element to connect with the electrode, the resistive element can be mounted in the passage 20 or in the electrical channel 6 of the body. Mounting the resistive element to the electrical channel 6 of the body is advantageous to ensure that the same potential exists on the inner surface of the cover component which prevents stability and surface current from being in that electrical channel. When a single power source is used within a single nozzle, a supply that is not regulated to a low power can be used if the discharge charging characteristic is desired, or a limiting resistor can replace the power supply circuit. When several nozzles are operated by a single power supply, it is desirable to use a resistive element for each nozzle, which resistor may be included in the power supply or the nozzle. This prevents the set one short nozzle from reducing the voltage of another nozzle operated by the same power source.

In order to establish and maintain a low surface outflow and high resistance between the nozzle power outlet and the ground plane, the method disclosed herein allows the use of suitable current limiting resistors without losing significant voltage to the electrodes. The resistor located in the body or somewhere in front of the electrode 18 has the advantage of limiting the current to a degree that is not dangerous when connected to the electrode 18, ie a contaminated nozzle surface is made. However, because a series of connections are connected to contaminated surface resistance, those who designed conventional nozzles have avoided. The main motivation for reducing the power required for induction nozzles is safety. A 9 mA of 800 V can often escape from the contaminated outer surface of any conventional commercially available nozzle of the general inductive charge shape with an excess capacity to compensate for the problem of high leakage current. It is not uncommon for the greatest risk to occur is not the electric shock itself, but the actions of the person who is quick to go to the source and drop and hit something. However, previous attempts have been made to use a limiting resistor or an unregulated source of low voltage, which is successful in safety but reduces electrode voltage and charge.

The graph shown in FIG. 10 shows the result of monitoring the electrical resistance of the conventional nozzle and the nozzle according to the invention from the induction electrode to the ground for a period of time in which the sprayed water contains common pesticides. The resistance of the spray mixture is approximately 28 ohm-cm for each solution (as compared to the dimensions for the number of taps typically being 5,000-10,000 ohm-cm). However, fertilizer mixtures of leaves containing copper fungicides are also characterized by forming thick coatings on nozzles, which have not been successfully tested in conventional nozzles. During the test, a fan is installed to blow some of the spray back to the nozzle front, virtualizing the situation that is often encountered when the charge nozzle is positioned to spray in the opposite direction, for example, in a vineyard spray. At the start of testing a conventional nozzle, the nozzle surface was cleaned and the resistance of the ground at the electrode was 11 megohms, which was close to the 15 megohm value of the power output decentralized resistor. Within one hour, the resistance of the ground at the electrode decreases to less than 1 kiloohm and changes substantially with the degree of resistive coating present on the nozzle. In this case, power limiting resistors are not used in conventional nozzles and cannot be used without significant loss of electrode voltage. The upper curve in FIG. 10 shows the results of a test using a nozzle according to the invention spraying a large amount of a mixture of a significant amount of copper fungicide with highly conductive pesticides. In this case, the high ground system resistance is maintained over the entire test time interval, and a series of 1.2 megohm resistors are used successfully. There is no electrical shock that can be felt when touching the charge nozzle cover, and even when applied substantially by spraying.

In addition, during this test, the spray charge degree is monitored for each nozzle, and the result is shown in FIG. The spray charge is determined by measuring the spray droplet group current, which is converted into charge per unit spray volume based on the liquid flow rate. For example, each nozzle has a liquid flow rate of 120 ml / min so that the current of the 10 mA spray droplet group is converted to a charge of 5 mC / l. The preferred degree of advantageously attached double charge as compared to the uncharged spray was previously determined to be in the range of 3 mC / l or more. Conventional nozzles charge a water spray with an electrical resistance of 6500 Ohm-cm to about 5.5 mC / l. However, by adding 10% of the chemical to the spray liquid, the charge initially decreases to only 3.8 mC / l, and also rapidly decreases below 2 mC / l when the nozzle surface is contaminated. The nozzle of the present invention charges the water spray at 7.5 mC / l and when both chemicals are added at 20%, the charge level is maintained at 7 mC / l over a 5-6 hour test interval.

12 shows a separate test in which the nozzle's supply current is monitored for the two nozzles as before. In this case, however, copper fungicides and foliar fertilizers are added to the mixture sprayed through conventional nozzles. The properties of copper lead to better nozzle coatings than foliar fertilizers alone. The end result is that the nozzle is irreversibly damaged, the main spray channel is deformed (changes the spray and internal electric field shape), and in less than 2 hours the dielectric liquid orifice tip is severely fitted and the nozzle Do not charge above 0.8 mC / l. Before the total failure of the tip, the current required for a conventional nozzle is usually 40 times or more than the current required to operate the nozzle according to the invention, while the degree of charge that can be obtained with the invention is three times or more than that of a conventional nozzle high. Therefore, the present invention provides more than 120 times spray current output per unit nozzle current input for conventional nozzles.

Another advantage, which has been established during this spray test, is the use of a new high impedance nozzle which does not form an electrical discharge peak and does not ionize the liquid even when it is intentionally poured into the front of the nozzle. However, induced ionization occurs continuously at any time in conventional devices. In addition, conventional nozzles exhibit corona discharges visible at the rim of the liquid orifice tip, and ionization and electrical discharge from the liquid when the liquid emerges from the tip. While this can increase the charge due to ion attachment, this eventually leads to failure of the liquid tip due to the formation and deformation of the physical holes in the tip rim.

The foregoing description introduces a preferred embodiment of the present invention. Other structures, designs, sizes, modifications, deletions and / or additions are aimed at producing nozzles or nozzle parts that produce similar effects to the nozzles and nozzle parts described above that can be used without departing from the spirit and scope of the invention. .

Claims (7)

Induction spray charged nozzle, Iii) a body having a liquid channel and a gas channel terminating at the tip; Ii) a cover formed at least in part from an insulating material and detachably connected to the body, a) an inner surface cooperating with an outer surface of the body and forming at least one void through which liquid released from the tip and gas released from the body flow; b) an electrode formed by the cover, which partially surrounds a channel shaped to atomize the liquid and gas passing therethrough to adequately release the air around the nozzle and generates an electrical charge in the liquid flowing into the channel; c) an outer surface shaped to reduce turbulence of air flowing adjacent the cover A cover having a; Iii) at least one annular cavity formed on the outer surface of the nozzle and shaped to reduce the introduction of liquids, gases and other surface contaminants and to reduce the current flowing between the electrode and ground; Induction spray charged nozzle characterized in that it comprises a. As a nozzle, Iii) a body having a gas channel and a liquid channel terminating at the tip; Ii) a cover formed at least in part from an insulating material and detachably connected to the body, a) an inner surface cooperating with the outer surface of the body and forming at least one void into which liquid discharged from the tip and gas released from the body flow; b) an electrode formed by said cover, which partially surrounds a channel shaped to atomize the liquid and gas passing therethrough to be properly released into the air around the nozzle and generates an electrical charge in the liquid flowing into the channel; c) a nozzle having an outer surface shaped to reduce turbulence of air flowing adjacent to the cover A cover having a; Iii) a conductive element for coupling the electrode to a power source; Iii) a conductive surface coupled to the cover, coupled to the conductive element, the conductive surface being generated such that the potential is substantially the same potential at a predetermined position on the inner surface of the cover; Iii) at least one annulus formed on the outer surface of the nozzle, the cavity being shaped to reduce the introduction of liquid, gas and other surface contaminants and the current flowing between the electrode and ground; Iii) a flange inserted between the body and the cover and at least partially shielding the annular cavity from liquid, gas and other surface contaminants and reducing the current between the electrode and ground Nozzle comprising a. As a nozzle, Iii) a body having a gas channel and a liquid channel terminating at the tip; Ii) a cover formed at least in part from an insulating material and detachably connected to the body, a) an inner surface cooperating with an outer surface of the body to form at least one void through which liquid released from the tip and gas released from the body flow; b) an outlet portion formed by the cover, the outlet portion being formed of a wear resistant material positioned adjacent to the channel, at least partially surrounding a channel shaped to atomize the liquid and gas passing therethrough to be properly released into the air around the nozzle, c) conductive elements that couple the electrodes to a power source; A cover having a; Iii) formed on the cover and tapered towards the channel of the cover to reduce the surface area of the nozzle adjacent to the channel and to allow liquid and gas discharged from the channel to attract air in the nozzle area and to reduce the adhered particles. Outer surface Nozzle comprising a. 4. The nozzle according to claim 3, wherein the cover further comprises an electrode formed of a wear resistant material. Induction spray charged nozzle, Iii) a body having a liquid channel and a gas channel; Ii) a cover at least partially formed of an insulating material and connected to the body, a) an inner surface cooperating with an outer surface of the body to form at least one void through which liquid released from the tip and gas released from the body flow; b) an electrode formed by the cover, which partially surrounds a channel shaped to atomize the liquid and gas passing therethrough so as to be properly released into the air around the nozzle, and causes an electrical charge to the liquid flowing into the channel; c) the outer surface has at least one field concentrator which is shaped for concentrating the strength of the electric field of the at least one cavity and the field concentrator region which is shaped to reduce the current flowing from the electrode to ground; Cover including Induction spray charged nozzle characterized in that it comprises a. As a nozzle, Iii) a body having a liquid transfer gas channel and a gas transfer gas channel terminating at the tip; Ii) a cover, formed at least in part of an insulating material, detachably connected to a body connected to said tip without seam so that current flows into the liquid, a) an inner surface cooperating with an outer surface of the body to form at least one void through which liquid released from the tip and gas released from the body flow; b) formed by the cover, formed of a wear resistant material positioned partially surrounding a channel shaped to spray the liquid and gas passing therethrough to be properly released into the air around the nozzle, thereby absorbing the charge of the liquid flowing into the channel Electrode generated A cover having a; Iii) a liquid grounded upstream from the tip; Iii) at least one torsional surface formed on a nozzle for imparting a torsion to a path of current flowing between the electrode and a ground liquid stream in communication with the liquid in the liquid channel to increase the surface's impedance with the current; Nozzle comprising a. As a spray-charged nozzle, Iii) a nozzle having a liquid channel for transferring liquid, a gas channel, and a discharge portion through which the sprayed liquid and gas are discharged into the air surrounding the nozzle of the desired spray shape, and which do not contain a seam through which no current flows through the liquid; main body; Ii) an electrode included in the nozzle for imparting charge to the liquid released into the air; Iii) a liquid line, a gas line, and an electrical line for providing liquid, gas and voltage to each of the liquid channel, gas channel and electrode, The liquid is grounded upstream of the outlet, And the nozzle has at least one torsional surface for imparting torsion in a current path flowing between the electrode and ground to increase the impedance of the surface with the current.