WO2008096190A1 - Appareil de pulvérisation électrostatique - Google Patents

Appareil de pulvérisation électrostatique Download PDF

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Publication number
WO2008096190A1
WO2008096190A1 PCT/IB2007/000298 IB2007000298W WO2008096190A1 WO 2008096190 A1 WO2008096190 A1 WO 2008096190A1 IB 2007000298 W IB2007000298 W IB 2007000298W WO 2008096190 A1 WO2008096190 A1 WO 2008096190A1
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WO
WIPO (PCT)
Prior art keywords
nozzle
spraying apparatus
liquid
housing
gas
Prior art date
Application number
PCT/IB2007/000298
Other languages
English (en)
Inventor
Johan Du Bois
Original Assignee
Johan Du Bois
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Johan Du Bois filed Critical Johan Du Bois
Priority to PCT/IB2007/000298 priority Critical patent/WO2008096190A1/fr
Publication of WO2008096190A1 publication Critical patent/WO2008096190A1/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
    • B05B5/025—Discharge apparatus, e.g. electrostatic spray guns
    • B05B5/03—Discharge apparatus, e.g. electrostatic spray guns characterised by the use of gas, e.g. electrostatically assisted pneumatic spraying
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B1/00—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means
    • B05B1/14—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means with multiple outlet openings; with strainers in or outside the outlet opening
    • B05B1/20—Arrangements of several outlets along elongated bodies, e.g. perforated pipes or troughs, e.g. spray booms; Outlet elements therefor
    • B05B1/205—Arrangements of several outlets along elongated bodies, e.g. perforated pipes or troughs, e.g. spray booms; Outlet elements therefor characterised by the longitudinal shape of the elongated body
    • 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
    • B05B5/053—Arrangements for supplying power, e.g. charging power
    • B05B5/0533—Electrodes specially adapted therefor; Arrangements of electrodes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B7/00—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas
    • B05B7/02—Spray pistols; Apparatus for discharge
    • B05B7/04—Spray pistols; Apparatus for discharge with arrangements for mixing liquids or other fluent materials before discharge
    • B05B7/0416—Spray pistols; Apparatus for discharge with arrangements for mixing liquids or other fluent materials before discharge with arrangements for mixing one gas and one liquid
    • B05B7/0441—Spray pistols; Apparatus for discharge with arrangements for mixing liquids or other fluent materials before discharge with arrangements for mixing one gas and one liquid with one inner conduit of liquid surrounded by an external conduit of gas upstream the mixing chamber
    • B05B7/045—Spray pistols; Apparatus for discharge with arrangements for mixing liquids or other fluent materials before discharge with arrangements for mixing one gas and one liquid with one inner conduit of liquid surrounded by an external conduit of gas upstream the mixing chamber the gas and liquid flows being parallel just upstream the mixing chamber

Definitions

  • This invention relates to electrostatic spraying apparatus and more particularly, but not exclusively, to electrostatic spraying apparatus for use in agricultural spraying applications.
  • Electrostatic sprayers are widely regarded as improving the deposition of agricultural chemicals, such as pesticides, onto the surfaces of plants by electrically charging the sprayed droplets.
  • the aim is for the charged droplets to be attracted, at least to some extent, to grounded plant surfaces by electrostatic forces, thereby reducing the loss of droplets into the atmosphere.
  • Mutual electrostatic repulsion between charged droplets also contributes to the formation of a more even distribution of droplets within the spray.
  • induction charging The most common method for charging the droplets is induction charging.
  • the uncharged spray liquid is atomised in an electric field created between the conductive liquid and an induction electrode adjacent the atomisation zone.
  • Induction charging nozzles which function with a potential difference of a few kilovolts, have been designed wherein the electrode is positioned very close to the liquid stream.
  • One type of induction charging nozzle uses a high speed air jet to atomise a liquid jet within a coaxial charging electrode.
  • Examples of atomising induction charging nozzles where the electrode is at high voltage and the sprayed liquid is at earth potential include US patents 4,004,733 to Law, 5,704,554 to Cooper and 6,227,466 to Hartman.
  • electrostatic sprayers indicated above they have not been used as widely as would have been expected.
  • One major problem has been current leakage that occurs between the high voltage areas, typically at more than 1 kV, and the grounded parts of the sprayer. Moisture and dust in the spraying environment come into contact with exposed high voltage electrodes or faulty high voltage connections. Currents then flow along conductive pathways formed by conductive liquid or by liquid residue that builds up over time. Current leakage eventually reduces the charging voltage to a level where charging is insufficient to enhance spray deposition.
  • leakage currents can also occur at spray liquid hose connections.
  • liquid connectors are often covered with a film of conductive spray.
  • the potential difference between the wet exterior of the hose connections and the interior spray liquid is often near the charging voltage. Over time these liquid connectors are prone to suffer from electrical breakdown resulting in leakage currents.
  • Hartman introduced a spraying module having a plurality of nozzles.
  • the module greatly simplified the assembly and configuration of a sprayer and improved the reliability of high voltage connections.
  • One problem still experienced by the Hartman module is the leakage of charge from the high voltage electrodes to grounded parts of the sprayer. In order to prevent this leakage of charge, the Hartman module requires regular cleaning during field use, thus adding to the operator's workload.
  • Hartman also attempted to overcome leakage problems by installing an entire assembly of air and liquid delivery pipes and nozzles in an outer shell.
  • the prior art sprayers also suffer from the disadvantage that conductive deposits leading to leakage currents can occur on internal nozzle and other surfaces. Leakage currents may then flow between the charging electrode and the spray liquid at the twin fluid tip of the nozzle (where liquid and atomizing air mix). Conductive contaminates can enter the nozzle and associated components in a number of ways. Firstly, during washing of the sprayer, water containing contaminates can enter the nozzle's gas passages via the spray outlet. A film of conductive residue may result on the inside of the nozzle after the water has evaporated. Secondly, small amounts of conductive deposits, such as carbon dust from tractor emissions, can enter the gas passages in the atomizing air and become deposited on internal surfaces. Lastly, with nozzles configured to spray in a horizontal or upward direction, spray liquid remaining in the twin fluid tip after the gas flow is turned off can enter the gas passage, also depositing conductive residue.
  • US Patent 5,765,761 also to Law, proposes a method for preventing the spray liquid from dripping by evacuating the spray liquid downstream by keeping the gas flow on longer than the flow of liquid, resulting in a venturi siphon effect sucking excess liquid out of the nozzle.
  • One disadvantage of this method is that it is difficult to control the exact time when spraying stops, since spraying continues for some time after the operator has shut of the spray liquid supply. It is preferable to stop spraying exactly when the sprayer reaches the end of a crop row to prevent unnecessary chemical waste and spray drift with accompanying pollution.
  • Another prior art method involves evacuating the spray liquid downstream by compressed gas.
  • a disadvantage of this method is that a large amount of spray liquid is discharged in a short time at the end of the spraying session. This may be wasteful or result in chemical overdose.
  • a still further prior art method is to suck the spray liquid back upstream by means of a vacuum but this involves additional vacuum apparatus.
  • the nozzle performance is greatly dependant on the exact positioning of the twin fluid tip within the electrode channel.
  • the twin fluid tip extends co-axially within a narrow electrode induction channel. Small co-axial variations can arise during regular use due to normal wear, residue buildup or small misalignments during reassembly after maintenance. Even small co-axial deviations can cause greatly unequal airflow around the twin fluid tip of prior art nozzles, resulting in uneven atomization and electrode wetting. Any spray that wets the electrode will be discharged.
  • Prior art sprayers are, as a general rule, also expensive to manufacture.
  • the Hartman module for example, contains many precision machined parts that increase the cost of the apparatus.
  • electrostatic spraying apparatus comprising a housing, at least one nozzle assembly passing through a hole in a wall of the housing, the nozzle assembly having a central tubular nozzle for conveying spray liquid from an inlet end to a twin fluid tip at an outlet end of the nozzle; an atomization zone at said outlet end of the nozzle; a generally annular gas passage surrounding the nozzle and communicating with the atomization zone for conveying atomising gas to the atomization zone; and a discharge channel communicating with the atomization zone in generally coaxial relationship relative to the nozzle and passing through a field electrode forming part of the spraying apparatus, the spraying apparatus being characterised in that the generally annular gas passage surrounding the nozzle communicates with the interior of the housing that itself serves as a supply conduit for the atomising gas.
  • the housing to be generally tubular with a plurality of longitudinally spaced nozzle assemblies located at selected positions, generally equidistantly, along the length thereof; for the ends of the generally tubular housing to have gas-tight connection means for connecting a plurality of housings in generally end-to-end relationship or to a supporting boom; and for a liquid supply pipe to be connected to the nozzle or nozzles and to extend through the interior of the housing or housings.
  • the field electrode being inherently electrically conductive
  • electrode means are associated with the liquid supply pipe or associated components for operatively applying an electrical high voltage charge to liquid within the supply pipe assembly; for the nozzle to the made of a dielectric material and preferably for the entire nozzle assembly other than the field electrode to be made of dielectric material; and for the housing to be made from electrically conductive material, preferably aluminium, with the field electrode or electrodes being in electrical contact therewith and the housing preferably being operatively earthed.
  • a further extremely important feature of the invention provides for the twin fluid tip of the nozzle to be spaced inwards relative to the inner end of the discharge channel through the field electrode in which instance the spray liquid supply needs to be pressurised to a pressure in excess of the pressure of the atomising gas where it enters the atomization zone. This is preferably achieved by pressurising the atomising gas and the liquid to the same pressure and causing an appropriate pressure decrease in the pressure of the atomising gas in the generally annular gas passage surrounding the nozzle and upstream of the atomization zone.
  • a spray nozzle assembly comprising a body and a tubular nozzle for conveying spray liquid from an inlet end to a twin fluid tip at an outlet end of the nozzle; and a field electrode operatively associated with the outlet end of the nozzle and having a discharge channel in generally coaxial alignment with the nozzle wherein an atomization zone is defined between the field electrode and nozzle at the outlet end of the nozzle, the nozzle assembly being characterised in that the body has an integral gas flow passage having oppositely directed open ends devoid of any coupling formations so as to be open to the surrounding atmosphere.
  • the body to have associated therewith a liquid flow passage communicating with the inlet end of the tubular nozzle, the liquid flow passage having oppositely directed integral coupling formations for attachment to generally collinear segments of a liquid supply pipe; for the liquid flow passage to be formed as a separate component releasably or permanently associated with the nozzle body; and for the nozzle to be formed either integral with the body or as a separate, removable and replaceable nozzle component.
  • the body and nozzle (whether or not it is integral with the body), to be injection moulded of a dielectric plastics material; for the field electrode to have either an externally screw threaded spigot received in an internally screw threaded socket in the body surrounding the nozzle, or an internally screw threaded socket for receiving and externally screw threaded spigot formed integral with the body; for the body to have an outer surface adjacent the field electrode shaped to be clamped to the inner surface of a housing of electrostatic spraying apparatus as defined above; for the field electrode to have a surrounding flange for operatively engaging the outer surface of a housing of electrostatic spraying apparatus as defined above; and for the field electrode to be injection moulded from an electrically conductive composite plastics material, typically a dielectric material containing an electrically conductive filler such as a powdered metal, typically powdered stainless steel or a suitable carbon material and optionally with a conductive metal liner defining at least a part of the length of the inner
  • the invention also provides as individual items of commerce nozzle bodies, separate nozzles (in the event that they are made removable) and field electrodes particularly adapted to form a nozzle assembly as defined above.
  • electrostatic spraying apparatus comprising at least one nozzle assembly having a central tubular nozzle for conveying spray liquid from an inlet end to a twin fluid tip at an outlet end of the nozzle; an atomization zone at said outlet end of the nozzle; a generally annular gas passage surrounding the nozzle and communicating with the atomization zone for conveying atomising gas to the atomization zone; a discharge channel communicating with the atomization zone in generally coaxial relationship relative to the nozzle and passing through a field electrode forming part of the spraying apparatus; supply pipes for conveying spray liquid from a reservoir to the inlet end of the nozzle and an atomising gas supply conduit for supplying atomising gas from a pressurised gas source to the generally annular gas passage surrounding the nozzle; the spraying apparatus being characterised in that the pressurised gas source is also connected to the interior of the spray liquid reservoir so that the spray liquid and atomising gas are supplied to the nozzle assembly substantially the same pressure and wherein the generally annular gas passage
  • Figure 1 is an exploded perspective view of a first embodiment of electrostatic spraying apparatus according to the invention
  • Figure 2 is an exploded perspective view of a nozzle assembly of the electrostatic spraying apparatus of Figure 1;
  • Figure 3 is a longitudinal section of one nozzle assembly mounted in the electrostatic spraying apparatus of Figure 1 ;
  • Figure 4 is a cross section of a nozzle assembly mounted in the electrostatic spraying apparatus of Figure 1;
  • Figure 5 is a schematic diagram illustrating one form of composite spraying apparatus according to the third aspect of the invention.
  • Figure 6 is an exploded perspective view of a second embodiment of electrostatic spraying apparatus according to the invention.
  • Figure 7 is an exploded perspective view of a nozzle assembly of the electrostatic spraying apparatus of Figure 6;
  • Figure 8 is a longitudinal section of one nozzle assembly mounted in the electrostatic spraying apparatus of Figure 6;
  • Figure 9 is a cross section of a nozzle assembly mounted in the electrostatic spraying apparatus of Figure 6;
  • Figure 10 is a schematic elevation of one arrangement of a number of electrostatic spraying apparatuses mounted together.
  • electrostatic spraying apparatus generally indicated by numeral (1) includes a tubular housing (2) having, in this instance, a sealed top end (3), an open bottom end (4) and a ridge (5) presenting a flat outer engagement face extending along its length.
  • the tubular housing is conveniently an aluminium extrusion, but, in any event, is electrically conductive.
  • a plurality of holes (6) extends through the housing in a spaced-apart configuration along the ridge.
  • a removable adaptor (7) is received in the open bottom end (4) of the tubular housing to provide an access connection to the housing.
  • the adaptor has a seal (8) for sealing against the cylindrical inner surface of the housing and a connector (9) at the outer end to which a gas pressure source, in this embodiment a gas supply hose (not shown), can be connected.
  • a removable composite multi-nozzle unit (10) extends into the housing through the bottom end.
  • the nozzle unit (10) includes a plurality of nozzle assemblies (10a) each having a nozzle body (11) connected to each other by segments of liquid supply pipe (12) and T-piece connectors (13) defining the liquid flow passages referred to above.
  • the liquid supply pipe segments and T-piece connectors form a straight composite liquid supply pipe assembly that, in this instance, is closed by a plug (14) at its free (upper) end.
  • a pipe connector (15) at its opposite end enables a liquid pressure source, in this embodiment a liquid supply hose (16), to be connected to the liquid supply pipe assembly.
  • Field electrodes (17) extend through the holes (6) in the housing and have screw threaded spigots (18) extending into cooperating sockets (19) formed integral with the nozzle bodies coaxially with their nozzles to support the nozzle assembly in the housing and secure it to the housing a wall.
  • the field electrodes (17) are made from conductive material and each field electrode has a flange (20) that, in the operative condition, engages, and is in electrical contact with, the housing that is maintained at earth potential in use.
  • the field electrode is made from an injection moulded plastics material filled with electrically conductive filler, such as stainless steel dust. Use of injection moulded material enables low-cost production to the effected.
  • a nozzle (21) has a tapered bore therethrough that extends from a connector (22) at an inlet end to a twin fluid tip (23) at the outlet end where the nozzle terminates in a small outlet orifice (24).
  • a cylindrical formation defining the socket (19) extends out of a contact surface (25) that surrounds it, the contact surface being shaped to conform to the inner surface of the housing with the cylindrical formation entering the hole (6).
  • the arrangement is such that an O-ring seal (26) can be effectively installed between the wall of the hole; the end of the cylindrical formation; and the flange of the field electrode.
  • the field electrode (17) has a dome-shaped head and a bore (27) therethrough extending from the stem to a small discharge channel (28) defining an outlet.
  • the bore is shaped so that a gap exists between the inner surface of the spigot and the outer surface of the nozzle (21) when the spigot of the field electrode is screwed into the socket of the nozzle body.
  • the nozzle body is shaped to provide a transverse gas flow passage (31) communicating with the inner end of the bore (27), the gas flow passage having oppositely directed open ends (32) that are devoid of any coupling formations so as to be open to the surrounding atmosphere within the housing. This is shown most clearly in Figures 3 and 4.
  • twin fluid tip terminates short of the inner end of the discharge channel (28) of the electrode, in an atomization zone indicated by numeral (33).
  • the bore (27) and outer surface of the nozzle are shaped so that atomising gas emerging adjacent the twin fluid tip of the nozzle has an increased velocity with which a decreased pressure is associated, the purpose of this being more fully described below.
  • an electrically conducting electrode element (34) extends through the electrically insulating liquid supply pipes (12) and T-piece connectors.
  • the conducting element ensures that the electrically conductive liquid is at the same potential throughout so that all nozzles receive liquid charged to the same voltage.
  • the conductive element is removable to allow for cleaning of the pipes (12).
  • electrostatic spraying apparatus as described above has the liquid supply pipe (12) connected to receive electrically conductive spray liquid from the bottom of an electrically insulated spray liquid tank (35) of a charge insulator assembly generally indicated by numeral (36). Downstream of the charge insulator the electrically conductive spray liquid is charged to a high voltage, typically about 800 volts to about 1500 volts, by a high voltage power supply (37) that is connected to the conducting element (34) (see Figures 3 and 4).
  • the conducting element extends along the entire length of the composite liquid supply pipe to ensure that the spray liquid is charged to even potential at each of the positions at which a nozzle is located.
  • the charge insulator assembly is a device that prevents electrical current from flowing upstream towards the spray liquid reservoir (38).
  • One example of such a charge insulator assembly is that described in United States patent 5,518,186 to Weinstein.
  • a pressure pump (39) supplies spray liquid under pressure to the interior of the electrically insulated tank (35) by way of an elevated outlet (40) that allows drops of spray liquid to fall into the tank without electrical connection being set up with the reservoir and pump assembly.
  • a bypass (41) returns to the reservoir in order to maintain circulation and mixing of the spray liquid and a level control valve (42) limits the maximum liquid level within the insulated tank.
  • the interior of the housing (2) is connected to a compressor (43) for receiving atomising gas the form of compressed air, the compressor typically being operated by a power take off from a tractor, for example, on which the spraying apparatus is carried.
  • the pressure of the compressor is limited by a relief valve (44) to that required, the operating pressure typically being selected within the range of from about 0.7 to 1.5 Bar.
  • the interior of the insulated tank is pressurised to the same pressure by way of a branch compressed air pipe (45) that has a restriction (46) therein for limiting the rate at which compressed air may enter the insulated tank for enabling pressure within the insulated tank to be lowered by way of a venting valve (47) communicating with the interior of the insulated tank.
  • a pressure gauge (48) enables the pressure within the insulated tank being monitored operational purposes. In use, with the interior of the insulated tank pressurised, the spray liquid under pressure forces the spray liquid out of the nozzle (21) in a narrow stream whilst gas pressure causes gas to flow through the bore to the discharge outlet (28).
  • the liquid exiting the orifice is impinged on by the gas in the gas atomisation zone (33), atomising the liquid into spray droplets. These droplets then pass through the electrode discharge channel (28) where they are charged by the electrical field created between the high voltage liquid and the grounded field electrode (17).
  • the fact that the operative liquid pressure is greater than the effective gas pressure at the twin fluid tip means that there is no siphon action in the gas atomisation zone.
  • the liquid pressure forces the liquid out in a narrow stream, and the gas impinges on the liquid stream to atomise it into droplets.
  • the pressure in the gas atomisation zone is therefore higher, not lower, than atmospheric pressure.
  • the orifice (24) can be larger than prior art orifices for the same flow rate. A larger orifice is less likely to become blocked and is easier to clean.
  • the possibility of leakage currents occurring is also considerably reduced by lengthening the shortest possible path between the high voltage liquid at the twin fluid tip (23) and the grounded parts of the apparatus.
  • the shortest conductive path that could develop would start at the twin fluid tip and extends all the way down the nozzle, along the inner surface of the nozzle body until it reaches the spigot of the field electrode (17). This path is indicated in Figure 4 by dotted line (48). Any liquid entering the nozzle body will also be drained through the open gas flow passage of the nozzle body, helping prevent such a conductive path from developing.
  • the arrangement is more tolerant to misalignment of the twin fluid tip (23) than prior art embodiments where the tip projects into the discharge channel in the electrode. Because the liquid stream is impinged on by the gas flow, should a small misalignment occur the gas pressures will force the stream towards the centre of the channel, resulting in a smaller possibility of electrode wetting while still providing a narrow focused spray.
  • Another benefit of this arrangement is that the electrode discharge channel can be made with a smaller diameter for a given flow rate, enabling a lower induction charging voltage to be used and resulting in better atomisation at lower gas pressures.
  • FIGS. 6 to 9 illustrate a second embodiment of electrostatic spraying apparatus according to the invention, showing a number of variations that can be made to the apparatus.
  • an electrostatic spraying apparatus includes a housing (51) having an open top end (52) that receives a removable plug (53), holes (54) along its length and a connecting flange (55) at its opposite end, the flange being laterally offset the axis of the housing and being orientated in a plane parallel thereto.
  • the flange (55) includes an O-ring (56) to provide sealing engagement with a surface to which the flange is clamped, typically that of a boom, as indicated below.
  • FIGS 7 to 9 show the nozzle body (57) having a removable nozzle (58) in more detail.
  • the nozzle body has a pipe section (59) integral therewith with an aperture having a socket (60) for receiving the removable nozzle (58).
  • the nozzle snaps into the socket by means of an O-ring (62) that may be a harder rubber and snap fits into a groove in the receiving socket.
  • a second softer O-ring (62a) at the inner end of the nozzle effectively seals the nozzle to the body.
  • the nozzle has an open ended liquid channel (63) therethrough that tapers to exit in a small orifice (64) at the twin fluid tip (65).
  • the nozzle body (57) includes gas flow passage (66) having oppositely directed open ends and an integral drip plate (67).
  • the drip plate has a centrally located aperture through which the nozzle extends.
  • the discharge channel is lined with a conductive lining (68).
  • the lining may be made from stainless steel to improve durability.
  • Figure 10 shows a typical arrangement of a number of spraying apparatus housings this type bolted to a boom (71).
  • the connecting flanges enable each housing to be mounted at a different angle depending on requirements.
  • the entire arrangement can be carried in a horizontal or vertical fashion.
  • spraying apparatus in a vertical arrangement of the spraying apparatus, pressure differences between upper and lower nozzles will generally cause dissimilar spray flow rates.
  • Colour-coded nozzles of different flow ratings could be inserted at different heights to ensure even spraying.
  • Flow rates could also be controlled by providing colour coded conductive spacers or washers for insertion between the housing and flange of the field electrode.

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  • Electrostatic Spraying Apparatus (AREA)

Abstract

L'invention concerne un appareil de pulvérisation électrostatique du type de ceux incluant un boîtier (2) dont une paroi présente un trou (6, 54) à travers lequel passe au moins un ensemble de buse (10a). Une buse tubulaire centrale (21, 58) transporte du liquide de pulvérisation d'une extrémité d'entrée à une buse double (23, 65) située à une extrémité de sortie de la buse et dans une zone d'atomisation (33). Un passage de gaz généralement annulaire (27) entoure la buse et communique avec la zone d'atomisation pour transporter le gaz d'atomisation à la zone d'atomisation et, de là, à un canal de décharge généralement coaxial (28) passant à travers une électrode de champ (17). Le passage de gaz généralement annulaire entourant la buse communique avec l'intérieur du boîtier qui sert lui-même de conduit d'alimentation pour le gaz d'atomisation. Typiquement, l'appareil présente plusieurs ensembles de buse espacés longitudinalement, situés à des positions sélectionnées le long de l'appareil. L'invention concerne également des buses et un appareil de pulvérisation composite.
PCT/IB2007/000298 2007-02-09 2007-02-09 Appareil de pulvérisation électrostatique WO2008096190A1 (fr)

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2438992A1 (fr) * 2010-10-07 2012-04-11 Alamos Vasquez, Adolfo Système pour l'application de produits liquides en agriculture
CN103875646A (zh) * 2014-03-13 2014-06-25 江苏大学 一种水田气力式静电喷杆喷雾机
CN104604831A (zh) * 2015-01-16 2015-05-13 南京林业大学 一种可调旋翼喷杆式静电喷雾装置
CN105098656A (zh) * 2015-09-15 2015-11-25 国网山东夏津县供电公司 移动式电力线路清理器
WO2019102171A1 (fr) * 2017-11-27 2019-05-31 Exel Industries Dispositif de pulvérisation
WO2020154653A1 (fr) * 2019-01-25 2020-07-30 Spraying Systems Co. Pulvérisateur centrifuge électrostatique à électrisation directe pulsée ou continue
WO2022010992A1 (fr) * 2020-07-08 2022-01-13 Spraying Systems Co. Agencement de mesure d'écoulement en ligne d'un pulvérisateur électrostatique
CN114887790A (zh) * 2022-05-13 2022-08-12 东莞市仙桥电子科技有限公司 一种用于电子元器件表面包覆保护膜的加工方法

Citations (8)

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Publication number Priority date Publication date Assignee Title
FR2098501A5 (fr) * 1970-06-09 1972-03-10 Tunzini Sames
US4004733A (en) 1975-07-09 1977-01-25 Research Corporation Electrostatic spray nozzle system
US5518186A (en) 1993-11-24 1996-05-21 Asahi Sunac Corporation Voltage block for electrostatic spraying apparatus
US5704554A (en) 1996-03-21 1998-01-06 University Of Georgia Reseach Foundation, Inc. Electrostatic spray nozzles for abrasive and conductive liquids in harsh environments
US5765761A (en) 1995-07-26 1998-06-16 Universtiy Of Georgia Research Foundation, Inc. Electrostatic-induction spray-charging nozzle system
US6138922A (en) * 1999-11-09 2000-10-31 Progressive Grower Technologies Electrostatic spray module
US6227466B1 (en) 1998-08-04 2001-05-08 William J. Hartman Electrostatic spray module
US20060124780A1 (en) * 2004-11-12 2006-06-15 Cooper Steven C Electrostatic spray nozzle with adjustable fluid tip and interchangeable components

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2098501A5 (fr) * 1970-06-09 1972-03-10 Tunzini Sames
US4004733A (en) 1975-07-09 1977-01-25 Research Corporation Electrostatic spray nozzle system
US5518186A (en) 1993-11-24 1996-05-21 Asahi Sunac Corporation Voltage block for electrostatic spraying apparatus
US5765761A (en) 1995-07-26 1998-06-16 Universtiy Of Georgia Research Foundation, Inc. Electrostatic-induction spray-charging nozzle system
US5704554A (en) 1996-03-21 1998-01-06 University Of Georgia Reseach Foundation, Inc. Electrostatic spray nozzles for abrasive and conductive liquids in harsh environments
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CN103875646A (zh) * 2014-03-13 2014-06-25 江苏大学 一种水田气力式静电喷杆喷雾机
CN104604831A (zh) * 2015-01-16 2015-05-13 南京林业大学 一种可调旋翼喷杆式静电喷雾装置
CN105098656A (zh) * 2015-09-15 2015-11-25 国网山东夏津县供电公司 移动式电力线路清理器
CN111565568B (zh) * 2017-11-27 2022-04-01 艾格赛尔工业公司 喷雾装置
WO2019102171A1 (fr) * 2017-11-27 2019-05-31 Exel Industries Dispositif de pulvérisation
FR3074016A1 (fr) * 2017-11-27 2019-05-31 Exel Industries Dispositif de pulverisation
EP3694320A1 (fr) * 2017-11-27 2020-08-19 Exel Industries Dispositif de pulvérisation
CN111565568A (zh) * 2017-11-27 2020-08-21 艾格赛尔工业公司 喷雾装置
WO2020154653A1 (fr) * 2019-01-25 2020-07-30 Spraying Systems Co. Pulvérisateur centrifuge électrostatique à électrisation directe pulsée ou continue
WO2022010992A1 (fr) * 2020-07-08 2022-01-13 Spraying Systems Co. Agencement de mesure d'écoulement en ligne d'un pulvérisateur électrostatique
CN114887790A (zh) * 2022-05-13 2022-08-12 东莞市仙桥电子科技有限公司 一种用于电子元器件表面包覆保护膜的加工方法
CN114887790B (zh) * 2022-05-13 2024-04-05 东莞市仙桥电子科技有限公司 一种用于电子元器件表面包覆保护膜的加工方法

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