WO2017063065A1 - Dispositif d'induction pour électrification de jets de gouttes de buses hydrauliques - Google Patents

Dispositif d'induction pour électrification de jets de gouttes de buses hydrauliques Download PDF

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Publication number
WO2017063065A1
WO2017063065A1 PCT/BR2016/050257 BR2016050257W WO2017063065A1 WO 2017063065 A1 WO2017063065 A1 WO 2017063065A1 BR 2016050257 W BR2016050257 W BR 2016050257W WO 2017063065 A1 WO2017063065 A1 WO 2017063065A1
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WO
WIPO (PCT)
Prior art keywords
induction
electrode
hydraulic
induction device
jet
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PCT/BR2016/050257
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English (en)
Portuguese (pt)
Inventor
Aldemir CHAIM
Celso VAINER MANZATTO
Luiz Guilherme REBELLO WADT
Marcelo Augusto BOECHAT MORANDI
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Embrapa - Empresa Brasileira De Pesquisa Agropecuária
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Publication of WO2017063065A1 publication Critical patent/WO2017063065A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B5/00—Electrostatic spraying apparatus; Spraying apparatus with means for charging the spray electrically; Apparatus for spraying liquids or other fluent materials by other electric means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B5/00—Electrostatic spraying apparatus; Spraying apparatus with means for charging the spray electrically; Apparatus for spraying liquids or other fluent materials by other electric means
    • B05B5/025—Discharge apparatus, e.g. electrostatic spray guns
    • B05B5/043—Discharge apparatus, e.g. electrostatic spray guns using induction-charging
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D1/00—Processes for applying liquids or other fluent materials
    • B05D1/02—Processes for applying liquids or other fluent materials performed by spraying
    • B05D1/04—Processes for applying liquids or other fluent materials performed by spraying involving the use of an electrostatic field
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D1/00—Processes for applying liquids or other fluent materials
    • B05D1/02—Processes for applying liquids or other fluent materials performed by spraying
    • B05D1/04—Processes for applying liquids or other fluent materials performed by spraying involving the use of an electrostatic field
    • B05D1/06—Applying particulate materials

Definitions

  • the present invention is in the field of electrostatic spraying with the use of hydraulic nozzles.
  • the growing interest in the use of electrostatic spraying for, among other possible uses, application of pesticides lies in the fact that greater deposition efficiency is obtained, since the electrically charged droplets are strongly attracted to the plant surfaces, directing them. effectively to the target of interest.
  • the object of the present invention relates to constructive solutions of supports provided with induction electrodes for use in hydraulic spray nozzles in conical jets or fans.
  • the induction device solutions of the present invention are primarily characterized by an arrangement attached to hydraulic nozzles for converting these conventional spray devices into electrostatic spray nozzles.
  • Such solutions proposed by the present technology aim to reduce the retraction phenomenon of electrically charged drops, which cause excessive wetting of the spray device.
  • the drop-back effect directly affects the operating efficiency of the device and therefore the quality of the deposition process obtained by electrostatic spraying.
  • the present induction device technology can be adapted to any type of sprayer using hydraulic nozzle, whether human, animal or mechanized.
  • electrostatic spraying reduces the side effects of pesticides on those organisms that live in the soil, considering that pesticide losses to the soil can be 20 times lower than those occurring with conventional spraying.
  • Some processes used to electrify spray drops are well known, such as: a) the direct electrification induction charging system in which the liquid is directly connected to a high voltage source and the drops acquire charge when there is a grounded body near the nozzle; b) the indirect induction charge system, where the liquid is grounded and the electrification of the drop occurs at the moment of its formation due to the existence of a high voltage electrode kept near the drop formation zone, or c) by the system corona charge when a pointed electrode ionizes air near the droplets, which in turn become charged when they collide with ionized air molecules.
  • the accumulated liquid on the induction electrode tends to undergo electrohydrodynamic spraying if the applied voltage is extremely high.
  • the droplets produced by electrohydrodynamic spraying have the same polarity as the electrode and thus tend to clash with the droplets electrified by induction.
  • operation results in too much wetting of the induction electrode as well as its support bracket, leaving the system highly prone to short circuiting between the high voltage of the induction electrode. electrode and spray nozzle body.
  • Patent document CN2920427 discloses a composite electrostatic spray device technology generated by the adaptation of a hydraulic spray nozzle.
  • a combined electrostatic charging structure is comprised of a cylindrical ring electrode and a conical geometry electrode.
  • the cylindrical rim electrode surrounds the body of the hydraulic nozzle and is sequenced by the conical geometry electrode which projects in the region ahead of the hydraulic nozzle tip.
  • the conical geometry electrode is provided with small tapered elements arranged uniformly along its inner surface at the opposite end region to that which connects to the cylindrical ring electrode.
  • the entire outer surface of the combined electrode array is surrounded by a layer of insulating material, with only the inner surface of the electrode exposed in conical geometry.
  • An electrostatic charging head for generating spraying of electrically charged drops from a hydraulic nozzle is the object described in patent document WO910181 1.
  • Said charging device provides a means for supporting an electrode positioned in front of the tip of a hydraulic nozzle, the structure constituting said device comprising a coupling support, an arrangement for housing the electrode, and a preferably shaped electrode. inverted "U".
  • the electrode housing has a sandwich construction, so that the electrode is embedded, leaving only the surface facing the inner side of the device exposed.
  • the constitution of the components such as the electrode support and the electrode housing, it is mentioned that they must be of plastics, preferably rigid, of smooth surface and low water absorption.
  • Patent document JP2009066597 discloses an electrostatic spray nozzle technology that aims to prevent the occurrence of electric shock accidents by providing the electrodes completely. waterproof material, preventing voltage drop due to leakage.
  • the technology consists of an electrode arranged in the vicinity of the nozzle tip, which is housed in a non-conductive material shell that covers the nozzle body.
  • Said cover comprises a cylindrical wrap body which is attached to the nozzle body and a cylindrical end frame fitted to the cylindrical wrap body.
  • the cylindrical rim-shaped electrode is positioned between the coupling faces of the cylindrical wrap body and the cylindrical end frame.
  • the technology taught in US5314123 relates to a spray arrangement including means for applying electrostatic charge to the drop jet of a hydraulic spray.
  • the electric charge application means includes an insulating body and an induction electrode supported by said body.
  • the electrode which consists of a metal ring, is housed in said insulating body so as to leave only its inner face facing the droplet region of the spray jet.
  • the factor that predominantly affects the phenomenon of retraction refers to the magnitude of the electrostatic field generated. How much The greater the intensity of the established electrostatic field, the more intense the drop retraction phenomenon will appear.
  • the high-speed jet creates turbulence in the air, causing it to flow in the same spray direction as the droplets. Acceleration of the air layer near the jet causes a percentage of the electrified droplets to drag out of the pull zone of the induction electrode, reducing its wetness.
  • a reduction in the wetting of the induction electrode as well as the body of the induction device can be achieved by the joint action of two factors: low attraction of the electrostatic field and drag of the droplet jet caused by turbulent air flow.
  • the intensity of the electrostatic field is high, as the droplets move slightly away from the spray device towards the target of interest, the intensity of the electrostatic field decreases significantly.
  • the electrostatic field intensity required for the proper electrification of the droplets in the region in which they are formed is obtained, and at the same time, the subsequent electrostatic field is obtained in the immediate vicinity. at such intensities as to exert less attraction under the charged drops. This results in a decrease in the retraction phenomenon, which results in less grinding of the induction electrode and the body of the induction device.
  • the induction electrode holder or device body, is constructed of rigid polymeric material, with polymeric materials being a natural choice because they are generally electrical insulators.
  • the hydrophobicity performance of the polymer is not taken into account.
  • the consequence of using For materials that do not have a high hydrophobicity index for the constitution of the device body after a certain amount of spraying time the surface of the device body (electrode support structure) is completely wet, and a thin continuous liquid blade
  • This condition is highly conducive to the generation of short circuit between the induction electrode and the spray nozzle and, consequently, impairing the electrification process of the system.
  • Another relevant aspect is related to the occurrence of leaks due to the presence of wetness; In this case, the induction voltage begins to decrease, leading to an increase in current consumption. This condition means increased cost and reduced operating efficiency of the device.
  • one way to prevent the formation of liquid slides on the exposed surfaces of the device is to use material which has a high hydrophobicity characteristic for the constitution of the device body (induction electrode support structure).
  • Hydrophobic materials are materials that have low affinity for water or, in other words, a high degree of water repulsion.
  • the drops deposited on surfaces formed of hydrophobic materials form bubbles that establish contact angle greater than 90 ° with the surface, characterizing a condition of low wettability.
  • Silicone rubber is a material classified as highly hydrophobic, such that the drops deposited on its surface form globules that establish a high contact angle and do not spread, generating a condition extremely not conducive to the formation of continuous liquid blades. This condition is extremely relevant when wetting the surfaces that constitute the body of the electrostatic spraying devices;
  • the resistance of the material to the formation of continuous liquid blades establishes a safe way to prevent the occurrence of disruptive discharges by constituting a path of low electrical resistance.
  • One way to prevent liquid buildup on the induction electrode surfaces without making use of the artifice to protect them by other structures is to reduce the surface area of the electrode, leaving exposure to a minimum area such that the accumulation of drops on the surface become difficult. This condition can be achieved by reducing the size of the induction electrode, resulting in a small exposed surface area, without detracting from the induction body function in the electrostatic induction process.
  • the present invention provides induction device solutions that are more efficient by, in addition to minimizing The incidence of the retraction phenomenon controlling the influence of the electrostatic field provides means of preventing the accumulation of liquid on the exposed surfaces of the device.
  • the proposed induction device solutions operate at low nominal voltage magnitudes and consist of a support structure made of silicone rubber, and a small induction electrode positioned in fully exposed configuration supported by said rubber structure. Silicone [026]
  • the use of low nominal voltage magnitudes associated with proper positioning of the induction electrode in the drop formation region provides a means of controlling the influence of the electrostatic field so that in the drop formation region the intensity of the droplet is obtained. field strength required for proper electrification of the droplets, and in the immediate vicinity obtain reduced field strength such as to result in a significant reduction of their influence on the already charged droplets, thereby reducing the unwanted phenomenon of retraction.
  • the present induction device technology proposes the use of silicone rubber for constituting the device body and reducing the dimensions of the induction electrode.
  • the present invention is concerned with induction device solutions which provide, through their coupling to hydraulic nozzles, the conversion of conventional spray devices into electrostatic spray devices.
  • the induction device solutions of the present invention essentially refer to a support structure for an induction electrode and an induction electrode.
  • the support structure constituting the body of the induction device is formed of hydrophobic material, such as silicone rubber;
  • the induction electrode is made of stainless steel wire with a diameter ranging from 0.7 to 1.5 mm.
  • the coupling of the induction device is made by means of the support structure, which has a cap shape and fits under pressure over the hydraulic spray tip fixing nut.
  • the electrostatic spray system generated by associating the present induction device with a hydraulic nozzle, operates with voltage magnitudes ranging from 1 kV to 6 kV.
  • the proposed induction device technology minimizes the incidence of the retraction phenomenon by controlling the influence of the electrostatic field, resulting from the application of low magnitude nominal voltages associated with the electrode positioning configuration.
  • induction Excessive accumulation of liquid on exposed surfaces of the induction device is prevented by the use of highly hydrophobic material to form the device body and the use of smaller induction electrodes.
  • Variations in induction device solution according to proposed technology relate to the geometry variations assumed by the induction electrode to suit the type of jet emitted by the hydraulic nozzle used together, assuming annular geometry for use with nozzles. cone jet hydraulics and parallel rod arrangement geometry for use with fan jet hydraulic nozzles.
  • Figure 1 shows in schematic form a classic induction system for conical jet nozzles.
  • Figure 2 - presents in schematic form a classic induction system for fan jet nozzles.
  • Figure 3a schematically illustrates locking nuts used on spray tips mounted on conical jet (A) and fan jet (B) hydraulic nozzles.
  • FIG. 5 Figure 5 - Front (VF), top (VS) and side (VL) views of the parallel rod array induction electrode embodiment, which makes up the induction device solution of the present invention for use with hydraulic nozzles. fan jet.
  • FIG. 6 Figure 6 - sectional side view of the induction device embodiment for use with conical jet hydraulic nozzles, in which the induction device consisting of the induction electrode (1) and its electrode support body (2) is observed. ), coupled to the conical jet hydraulic nozzle (2) by snap-fitting onto the lock nut (5), and the connection of the induction electrode (2) to the high voltage cable (4) through the thickness of the structure in the form of a cap that forms the support body of the electrode (2).
  • FIG. 7 Side view of the embodiment of the induction device for use with conical jet hydraulic nozzles, in which the induction electrode (1), the electrode support body (2), the conical jet nozzle ( 3) and the high voltage cable (4).
  • FIG 8 - top view of the induction device embodiment for use with conical jet hydraulic nozzles, wherein the induction electrode (1), electrode support body (2) and high voltage cable ( 4).
  • FIG. 9 Front view of the induction device embodiment for use with conical jet hydraulic nozzles, in which the induction electrode (1) and electrode support body (2) are observed.
  • FIG 10 Figure 10 - sectional side view of the induction device embodiment for use with fan-jet hydraulic nozzles, in which the induction device consisting of the induction electrode (1) and its electrode support body (2) is observed. ), coupled to the fan-jet hydraulic nozzle (2) by snap-fitting onto the lock nut (5), and connecting the induction electrode (2) to the high voltage cable (4) through the thickness of the structure in the form of a cap that forms the support body of the electrode (2).
  • Figure 1 1 Side view of embodiment of induction device for use with fan-jet hydraulic nozzles, in which induction electrode (1), electrode support body (2), conical jet nozzle are observed. (3) and the high voltage cable (4).
  • FIG 12 Figure 12 - top view of the embodiment of the induction device for use with fan-jet hydraulic nozzles, in which the induction electrode (1), electrode support body (2) and high voltage cable ( 4).
  • FIG. 13 Front view of the induction device embodiment for use with fan-jet hydraulic nozzles, in which the induction electrode (1) and the electrode support body (2) are observed.
  • Figure 14 - presents the historical evolution of research on drop electrification technology with the use of hydraulic nozzles, showing from left to right: (a) device with large diameter brass induction electrode, which required a threaded pipe extension; (b) a device with a large diameter induction electrode protected by a polytetrafluoroethylene structure for fitting into the spray tip fixing nuts; (c) a device with a smaller diameter brass induction electrode mounted on a rigid polytetrafluoroethylene support, said rigid support covering the spray tip retaining nut and thus requiring a length of tubing with screw thread; (d) model of induction device, fitted with induction electrode made of stainless steel in 13 mm diameter ring geometry, and respective support of the silicone rubber molded electrode, which fits over the fixing nut of the pulverization; (e) model of induction device, fitted with a 23 mm diameter stainless steel ring geometry induction electrode and its silicone rubber molded electrode holder, which fits over the tip locking nut pulverization.
  • Figure 15 - (I) first prototype induction device constructed with acetic silicone glue, fitted with a steel induction electrode stainless in ring geometry 13 mm in diameter; (II) deposition obtained using said prototype coupled to a conical jet hydraulic nozzle with a flow rate of 200 m L / min and 1.5 kV voltage applied to the electrode.
  • Figure 16 - Front (I) and side (II) details of one embodiment of the induction device of the present invention for use with conical jet hydraulic nozzles consisting of an electrode support body made of silicone rubber and an electrode induction ring in 23 mm diameter.
  • Figure 17 - Front (I) and side (II) details of an embodiment of the induction device of the present invention for use with fan-jet hydraulic nozzles consisting of an electrode support body made of silicone rubber and an electrode. of induction structured in parallel rods separated by a distance of 23 mm.
  • FIG 18 - embodiments of the induction device of the present invention the induction device having an annular geode electrode being on the left and the induction device having an electrode in parallel rod arrangement on the right;
  • a conical jet nozzle for the device having an annular electrode and a fan jet nozzle for the device is provided with an electrode in parallel rod arrangement, and in both nozzles are mounted the fixing nuts used for the snap fit of the respective induction device.
  • Figure 19 shows two embodiments of an induction device with an electrode in annular geometry, the main difference between them being the distance between the end of the conical region of the electrode support body and the ring structure of the electrode. induction electrode.
  • Figure 20 - illustrates the resulting wetting in the silicone rubber electrode support body as an effect of the distance configuration between the induction electrode ring structure and the region end tapered electrode support body; It is observed that in the configuration of a device whose electrode is positioned closer to the end of the conical region of the electrode support body, the electrode suffers less effect of air flow promoted by the droplet turbulence, causing greater wetting of the rubber structure. silicone which forms the support body of the induction device.
  • Figure 21 - illustrates the induction device with parallel rod arrangement electrode coupled to a fan-jet hydraulic nozzle in spray operation, but without induction electrode electrification (inoperative induction device );
  • II illustrates the induction device provided with parallel rod array electrode coupled to a working fan jet nozzle with electrification of the induction electrode; liquid is deposited on the induction electrode surfaces.
  • Figure 22 - (I) shows an electrostatic spray device in operation, obtained by coupling the present induction device with electrode in arrangement of rods parallel to a fan jet nozzle with flow 900 m L / min; (II) illustrates the effect of electrified droplet jet dispersion, which is corroborated by the fact that the droplets have a charge of the same polarity.
  • FIG 23 - illustrates a deposition experiment performed with the induction device object of the present invention coupled to a fan-jet hydraulic nozzle, where: in (I) the induction device is inoperative (without electrification of the droplets). ), and there are no spots of droplet deposition on the yellow cards, positioned on the opposite side of the target angle of the spray jet; In (II) there are blue spots on the yellow card, associated with the deposition of drops of the electrified jet, using the induction device coupled to the hydraulic nozzle.
  • Figure 24 - presents images referring to the same deposition experiment performed and shown by Figure 23, and (I) and (II) show in greater detail the deposition of drops on the yellow cards, resulting electrostatic spraying performed using the induction device object of the present invention.
  • Figure 25 - illustrates the dimensional variation of commercially available hydraulic spray tips.
  • the present invention relates to constructive solutions of induction devices for use in conical or fan jet hydraulic nozzles for converting these conventional nozzles into electrostatic spray devices.
  • the invention is preferably, but not restrictively, intended for the application of pesticides and may be used in costal, animal traction or motorized spraying equipment.
  • Constructive solutions as proposed by the present induction device technology essentially refer to a support structure for an induction electrode, and an induction electrode.
  • the support structure which forms the body of the induction device, is capped and fits under the locking nut of the hydraulic spray tip.
  • the induction electrode is fixed to this support structure by means of an auxiliary rod, assuming an exposed configuration, such that when the induction device is coupled to a hydraulic nozzle, the electrode is automatically positioned in front of the jet outlet port. drops emitted by the hydraulic nozzle.
  • agricultural spray nozzles can be classified into conical jet nozzles, or flat or nozzle nozzles, both of which are suitable for use in systems.
  • induction electrification Whether in the conical jet or fan jet configuration, these nozzles have elements or structures inside that force the liquid to emerge from the outlet orifice into a thin blade that breaks into droplets as it hits the air a short distance from the orifice. of emergency.
  • This thin sheet of liquid is fundamental in the induction process as it allows the displacement of electric charges in the liquid when there is a field electrostatic device from an electrified electrode positioned near the drop formation zone.
  • Figures 1 and 2 show schematically how the classical induction process takes place, with the induction electrode positioned near the drop formation zone of a conical jet hydraulic nozzle and a fan jet hydraulic nozzle. respectively.
  • the liquid In indirect induction charging systems such as that used by the present invention, the liquid must always be grounded for the system to function properly.
  • the induction electrodes are positively biased, thus attracting negative charges to the edge of the liquid blades, and repelling the positive charges to the grounding system. The liquid slides break into drops, leading to negative charges.
  • Such influence control results from a joint action generated by the application of low voltage magnitudes to the system and the positioning configuration of the induction electrode.
  • the constructive solutions proposed by the present invention make use of highly hydrophobic material for the constitution of the device body (electrode holder) and induction electrodes built in small dimensions.
  • the constitution of the device body in super hydrophobic material, such as silicone rubber, results in an exposed surface condition of the device body that, even when wetted, does not allow the formation of continuous liquid blades, once the deposited drops form non-spreading blood cells.
  • the risk associated with the formation of continuous liquid blades on the body surfaces of the device is due to the fact that these blades would constitute a low resistance path, providing the generation of short circuits and thus compromising the operating safety of the device.
  • electrostatic spray device The significant reduction in the dimensions of the induction electrode generates a minimum exposed area condition, so that the accumulation of liquid on the induction electrode is very difficult.
  • the induction devices of the present invention are characterized by having electrodes made of stainless steel wire whose diameter varies from 0.7 to 1.5 mm. This configuration represents obtaining induction electrodes whose dimensions are substantially reduced compared to those found in prior art electrostatic spray devices. Dimensions of this magnitude cause the electrodes to settle in a minimal exposed area condition, making it difficult to deposit droplets and thus preventing the accumulation of liquid on their surfaces.
  • Figure 4 shows the configuration of the induction electrode for use with conical jet hydraulic nozzles, characterized in that it has ring-shaped geometry and is provided with a lateral support rod, used to fix the electrode to the device body.
  • the configuration of the induction electrode for use with fan jet hydraulic nozzles is shown in Figure 5;
  • the electrode is configured in an arrangement of two rods parallel to each other and parallel to the plane of the spray jet outlet surface, and these parallel rods are interconnected by their corresponding ends by means of roughly shaped geometry structures. Tais ". Such estruturas" structures provide the means for securing the rod arrangement parallel to the body of the device.
  • the hollow cone type hydraulic jet nozzles have diffuser elements inside that promote the rotation of the liquid before its emergence through the outlet hole. Considering a high-speed spin condition, the liquid will produce a thin hollow tapered blade that will progressively taper until it breaks into drops as bump into the air. The angle formed by this liquid cone blade will depend on the diffuser element design and spray nozzle hole characteristics.
  • the base of the tapered blade where the blade breaks into drops, may have a diameter ranging from 10 to 15 mm, depending on the particularities of the spray tip used and the pressure variations that exist between the different types of sprayers. , which may be associated with motorized or hand driven compressor pumps.
  • the electrode positioning distance from the droplet zone should be equivalent to 1.0 mm for each applied kV voltage.
  • the ring-shaped geometry electrode may have an internal diameter ranging from 12 mm to 25 mm.
  • the voltage applied to perform the induction process may also vary from 1.0 to 6.0 kV.
  • induction electrode ring diameters and nominal voltage applied to the system are thus proposed also considering the possibility that the present induction device technology may be used in sprayers making use of air flow, which would reduce the diameter of the base of the cone generated by the liquid blade, region where the blade breaks into drops.
  • the blade is theoretically formed essentially according to the shape of the spray jet outlet orifice.
  • the electrode associated with the induction device for use with fan-type hydraulic jet nozzles allows great simplification in its construction, requiring only two electrically conductive parallel rods, properly positioned in relation to the jet, to allow the droplet loading by the electrostatic induction process. .
  • the rods should be positioned parallel and lateral to the jet plane, such that the jet plane is established between the two hates. From practice, however, it is observed that many drops escape laterally to the plane of the fan jet, so that the generated drop jet assumes an oblique distribution.
  • the rods should be positioned apart from each other for sufficient distances that do not constitute a direct wetting condition of their surfaces.
  • the distance that the rods should keep from each other can vary between 15 and 25 mm, depending on the characteristics of the fan-type hydraulic jet nozzle with respect to the outlet orifice, as well as operating parameters such as the jet outlet pressure. pulverization. Similar to the considerations made for the ring-shaped electrode, if the induction device is associated with sprayers that make use of airflow, there is a possibility that the fan-shaped liquid blade produced will suffer dimensional and spatial changes. This will necessitate adjusting the separation distances of the parallel rods that define the induction electrode, as well as the magnitude of voltage applied to the system.
  • the induction devices of the present invention are further characterized by comprising a support structure for the induction electrode, called the electrode support body.
  • a support structure for the induction electrode called the electrode support body.
  • Such a structure forms the body of the induction device and is cap-shaped so as to generate a coupling cavity for the internal fitting of the hydraulic spray nozzle.
  • the opening of this cavity is through the rear side of the cap-like structure, and the front side is provided with a channel for engaging the end of the hydraulic nozzle, corresponding to that containing the outlet of the spray jet.
  • the induction electrode is fixed externally to the shell-like structure and to the front side of it, that is, such that the electrode is positioned in front of the channel for engaging the end of the hydraulic nozzle containing the jet outlet orifice.
  • the positioning and attachment of the ring to the support body is accomplished by means of a support rod, affixed to the support body through the thickness of the material. in the region peripheral to the channel for engaging the end of the hydraulic nozzle.
  • the electrode configured in parallel rod arrangement the positioning and fixation of this arrangement is similar to that described for the ring structure of the annular electrode, differing in that the parallel rods are attached to the support body in two points, positioned in the region peripheral to the channel for engaging the end of the hydraulic nozzle and in opposite symmetry, through the estruturas "structures that constitute its supporting structures.
  • the electrode support body according to the solutions proposed by the present invention is constituted of highly hydrophobic material, such as silicone rubber.
  • silicone rubber is one that, in addition to providing a high degree of water repulsion, bringing benefits of extreme relevance to electrostatic induction device technology, yet offers better electrical insulation properties at high voltage magnitudes.
  • silicone rubbers among which are hot vulcanizable, cold vulcanizable and liquid silicone rubbers.
  • Laboratory tests performed with electrostatic induction devices whose support bodies were constructed with two-component liquid silicone rubber showed that drops attracted to the body of the device and deposited on surfaces made of such material promote the formation of non-spreading liquid globules. It is also observed that the electrification of the droplets remains stable, with little or no influence in terms of change of applied induction voltage, or increase of current consumption.
  • the electrode support body (induction device body), which must be made of highly hydrophobic material, can then be molded into silicone rubber.
  • THE Figure 3 shows schematically the spray tip fixing nut under which the electrode support body is coupled under pressure; where (A) shows the lock nut on a tapered jet spray tip and (B) shows the lock nut on a fan jet spray tip.
  • the electrode support body when coupled to a tapered or fanned hydraulic nozzle automatically positions the induction electrode in front of the spray jet outlet orifice at a distance from this corresponding orifice. to the drop formation region.
  • the induction electrode is connected to the high voltage cable through the auxiliary support rod of the electrode.
  • This auxiliary support rod in addition to securing the ring structure of the induction electrode to the support body, establishes the connection of the electrode to the high voltage cable, which occurs through the thickness of the cap structure that forms the electrode support body.
  • the difference to the parallel-rod structured electrode is that although such an arrangement is fixed to the support body by two ⁇ "-supporting auxiliary structures, the connection to the high voltage cable is by using only one of these two structures.
  • ⁇ " which connects the induction electrode in parallel rod arrangement to the high voltage cable through the thickness of the structure that forms the electrode support body.
  • Figures 6 and 7 show schematically the electrostatic spray system generated by the coupling of the induction device solution of the present invention, provided with an annular electrode coupled to a conical jet hydraulic nozzle.
  • Figures 10 and 11 schematically show the electrostatic spray system generated by the coupling of the induction device solution of the present invention, provided with a parallel rod arrangement structured electrode coupled to a fan jet hydraulic nozzle.
  • Figures 6 and 10 show the internal coupling arrangement of the electrode support body over the spray tip retaining nut, with Figure 6 corresponding to the configuration of the electrode holder.
  • Figure 6 ring shaped induction electrode associated with a conical jet type spray tip
  • Figure 10 illustrates the induction electrode configuration provided with parallel rod arrangement associated with a fan jet type spray tip.
  • Figures 7 and 11 the induction device is seen as seen from the outside, covering the hydraulic spray tip, so that only the extreme region containing the spray tip outlet port projects towards the external means through the channel comprised in the anterior side of the electrode support body.
  • Figure 6 corresponds to the system generated by the induction device with annular electrode associated with a conical jet hydraulic nozzle
  • Figure 11 corresponds to the system generated by the induction device with parallel rod arrangement electrode associated with a hydraulic nozzle Jet fan.
  • Figures 8, 9, 12 and 13 show further views of the induction device solutions of the present invention, showing aspects of geometry and positioning of the induction electrode fixture, and of the shape of the shell constituting the support body of the induction device. electrode.
  • Figures 8 and 9 correspond to the induction device solution provided with annular electrode
  • Figures 12 and 13 correspond to the induction device solution provided with parallel rod arrangement electrode.
  • the configuration of the electrode support body is such that the assumed shell shape still has taper on the anterior side, tapering gently towards the end where the spray tip termination groove channel containing the spray jet outlet port is located.
  • This configuration aims to improve aerodynamic aspects of the device body surfaces to facilitate the air flow produced by the turbulent action of the droplet jet.
  • the drop zone is at a distance of 4 to 7 mm from the nozzle outlet hole.
  • the cap-like structure constituting the electrode support body can be molded to fit unrestrictedly with any spray tip attachment or device such as quick coupler systems
  • schematic representations shown in the figures only illustrate induction device coupling configurations in which the spray tips are equipped with threaded nuts to secure tips such as those used in costal spray systems.
  • the same inventive concept that characterizes the support body of the induction electrode as defined by the present technology and preferably made of silicone rubber
  • the adaptation of an electrode support structure for coupling in quick coupler systems not illustrated here due wide range of models
  • existing for cone or fan type spray tips and used in tractor equipment.
  • aerodynamic optimization with respect to the shape of the silicone rubber electrode support body eg ovoid shapes
  • auxiliary air flow sprayers should be interpreted. broadly, such that alternative embodiments are covered within the scope of the present technology as disclosed.
  • the induction device solutions proposed by the present invention besides representing technological advancement in the field of electrostatic spraying with the use of hydraulic nozzles, allowing the expressive mitigation of the negative effects associated with the incidence of the drop retraction phenomenon, still present. the advantages of providing improved aspects of operating safety, and facilitating part cleaning and part replacement operations of the generated electrostatic spray system.
  • Figures 15-24 refer to images of embodiments of the induction device solutions of the present invention, and of results obtained from operation tests performed with such embodiments associated with conical jet and fan jet hydraulic nozzles.
  • Figure 15 illustrates the first prototype constructed and the result of electrostatic deposition obtained from its use in association with a conical jet hydraulic nozzle.
  • Image (I) shows the prototype whose electrode support body was made with silicone rubber, more specifically with acetic silicone glue. Such a silicone compound has the disadvantage of having very molding aspects difficult.
  • Image (II) shows the result of the deposition of drops obtained on water-sensitive cards, positioned on the posterior faces of a target made of a stainless steel corner with 80 mm flaps. Electrostatic spraying was performed with a short pass of the spray jet, emitted at a flow rate of 200 m L / min and at a distance of 30 cm from the corner corner.
  • the ring-shaped geometry induction electrode had a diameter of 13 mm, and the applied induction voltage was about 1.5 kV. Electrically charged drops were found to bypass the target and settle on the posterior faces of the target, resulting in a reasonable degree of deposition.
  • Figures 16 and 17 respectively illustrate embodiments of the induction device of the present technology for use with conical jet and fan jet hydraulic nozzles.
  • the embodiment shown in Figure 16 has an induction electrode in annular geometry
  • the embodiment shown in Figure 17 has an induction electrode in parallel rod arrangement.
  • Figure 18 shows the embodiments of the induction device with respect to the variation of the induction electrode, each accompanied by the corresponding type of hydraulic nozzle intended for use in combination: the left of the image shows the induction device with annular electrode and the tapered jet spray tip on its side, and on the right, the induction device provided with parallel rod arrangement electrode and fan jet spray tip on its side.
  • the electrode support body in both embodiments was made by molding two-component silicone rubber (liquid rubber and catalyst).
  • Figure 19 illustrates two induction device prototypes for use with conical jet hydraulic nozzles, the support body of both being silicone rubber and both induction electrodes characterized by 23 mm diameter rings, but the electrodes having different spacing positions with respect to the support body, so that in one of the prototypes the induction electrode is further away from the conical surface region of the electrode support body.
  • THE Electrification of the electrodes was provided by a single source of 4 kV magnitude.
  • the result of the deposition obtained can be observed according to the image shown in Figure 20: the configuration of the device whose induction electrode was positioned closer to the support body, resulted in higher incidence and extension of wetting of the exposed surfaces of the device body.
  • the presence of the induction electrode closer to the surfaces of the support body impaired the aerodynamic drag of the air flow provided by the high-speed droplet, and therefore caused greater wetting.
  • Figure 21 shows an embodiment of the induction device coupled to a fan-jet hydraulic nozzle.
  • Image (I) shows the spray system generated in operation, but without electrification.
  • Image (II) shows the same spraying system, but electrified; drops are present on the parallel rods of the induction electrode as a consequence of the incidence of the retraction phenomenon.
  • Figure 22 illustrates a working electrostatic spray system generated by coupling the induction device of the present invention to a fan jet hydraulic nozzle.
  • the system operated at a flow rate of 900 m L / min and a 4 kV voltage polarized induction electrode. It is possible to observe the maximization of the distribution of the drops in the generated spray jet, considering that the electrified drops move away from the jet plane by having a repulsion effect between them, since they have charges of the same signal.
  • Figure 23 shows a working electrostatic spray system generated by coupling the induction device of the present invention to a fan jet hydraulic nozzle.
  • the image (I) shows the system in spray operation, but without electrification; There are no stains on the water-sensitive cards, proving no deposition on them.
  • the picture (II) is shown the same system, but in operation of electrostatic spraying; droplet deposition is confirmed by the existence of small blue spots on the cards.
  • Figure 24 shows result of the same experiment, being possible to observe by the amount of stains in the cards the existence of expressive drop deposition, obtained with less than one second of spraying operation.

Landscapes

  • Electrostatic Spraying Apparatus (AREA)
  • Catching Or Destruction (AREA)

Abstract

La présente invention trouve une application dans le domaine de la pulvérisation électrostatique, et concerne notamment des dispositifs d'induction pouvant être accouplés à des buses hydrauliques, offrant un moyen de convertir des dispositifs de pulvérisation classiques en dispositifs de pulvérisation électrostatique. Les solutions de dispositif d'induction de la présente invention concerne essentiellement une structure de support pour une électrode d'induction, ainsi qu'une électrode d'induction. La structure de support constitue le corps du dispositif d'induction et est formée d'un matériau hautement hydrophobe, et l'électrode d'induction est réalisée en fil d'acier inoxydable et possède des dimensions réduites. L'électrode d'induction présente une géométrie annulaire en vue d'une utilisation avec des buses hydrauliques à jet conique et une géométrie en agencement de tiges parallèles en vue d'une utilisation avec des buses hydrauliques à jet éventail. Les systèmes de pulvérisation électrostatique résultants, produits par association des présentes solutions de dispositif d'induction à buses hydrauliques, fonctionnent à de faibles niveaux de tension et permettent de réduire le phénomène de rétroaction de gouttes chargées électriquement, et d'éviter l'accumulation excessive de liquide sur les surfaces exposées du dispositif. Le phénomène de rétroaction de gouttes provoque le mouillage excessif du dispositif de pulvérisation, affectant directement son efficacité de fonctionnement et, par conséquent, la qualité du procédé de dépôt électrostatique.
PCT/BR2016/050257 2015-10-13 2016-10-11 Dispositif d'induction pour électrification de jets de gouttes de buses hydrauliques WO2017063065A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
BR102015025940-9A BR102015025940B1 (pt) 2015-10-13 2015-10-13 dispositivo de indução para eletrificação de jatos de gotas de bicos hidráulicos
BRBR102015025940-9 2015-10-13

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WO2019113660A1 (fr) 2017-12-13 2019-06-20 Tecnopampa Indústria De Máquinas Ltda Extension isolée pour pulvérisation avec assistance électrostatique
WO2020154655A1 (fr) * 2019-01-25 2020-07-30 Spraying Systems Co. Dispositif d'induction d'ensemble de buses de pulvérisation électrostatiques
CN113145417A (zh) * 2021-04-02 2021-07-23 杨家胜 一种铝合金型材的静电喷涂工艺
US20230201849A1 (en) * 2019-01-25 2023-06-29 Spraying Systems Co. Electrostatic centrifugal sprayer with pulsed or continuous direct electrification

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019113660A1 (fr) 2017-12-13 2019-06-20 Tecnopampa Indústria De Máquinas Ltda Extension isolée pour pulvérisation avec assistance électrostatique
US11292017B2 (en) 2017-12-13 2022-04-05 Tecnologia Sul Brasileira Indústria de Máquinas LTDA Insulated electrostatically assisted spraying extender
WO2020154655A1 (fr) * 2019-01-25 2020-07-30 Spraying Systems Co. Dispositif d'induction d'ensemble de buses de pulvérisation électrostatiques
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US20230201849A1 (en) * 2019-01-25 2023-06-29 Spraying Systems Co. Electrostatic centrifugal sprayer with pulsed or continuous direct electrification
CN113145417A (zh) * 2021-04-02 2021-07-23 杨家胜 一种铝合金型材的静电喷涂工艺

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