US2826513A - Method and apparatus for electrostatic coating utilizing projection of liquid solelyby the electric field - Google Patents

Method and apparatus for electrostatic coating utilizing projection of liquid solelyby the electric field Download PDF

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Publication number
US2826513A
US2826513A US555999A US55599955A US2826513A US 2826513 A US2826513 A US 2826513A US 555999 A US555999 A US 555999A US 55599955 A US55599955 A US 55599955A US 2826513 A US2826513 A US 2826513A
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Prior art keywords
liquid
orifice
nozzle
electrode
electric field
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US555999A
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English (en)
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Blanchard Andre
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    • 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
    • B05B5/0255—Discharge apparatus, e.g. electrostatic spray guns spraying and depositing by electrostatic forces only
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B17/00—Apparatus for spraying or atomising liquids or other fluent materials, not covered by the preceding groups
    • B05B17/04—Apparatus for spraying or atomising liquids or other fluent materials, not covered by the preceding groups operating with special methods
    • B05B17/06—Apparatus for spraying or atomising liquids or other fluent materials, not covered by the preceding groups operating with special methods using ultrasonic or other kinds of vibrations
    • B05B17/0607—Apparatus for spraying or atomising liquids or other fluent materials, not covered by the preceding groups operating with special methods using ultrasonic or other kinds of vibrations generated by electrical means, e.g. piezoelectric transducers
    • 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
    • B05B5/08—Plant for applying liquids or other fluent materials to objects
    • B05B5/12—Plant for applying liquids or other fluent materials to objects specially adapted for coating the interior of hollow bodies

Definitions

  • a machine particularly adapted for coating the inside of vessels such as preserving cans by means of at suitable insulating liquid, e. g. a lacquer, a varnish, or
  • a an emulsion said machine incorporating one or more colloidal suspensions, whereby as a practically sole trans- Y fer means, use is made of a high tension electric field established between two electrodes, one of which is either the surface to be coated itself which is in this case conducting, or a conducting surface which is in contact with the surface to be coated, said surface to be coated being either conducting or not and positioned between the electrodes.
  • the other electrode is in contact with a continuous homogeneous body of liquid material contained within an insulating nozzle the orifice of which is directed toward the surface to be coated. The liquid in the nozzle moves fairly slowly in order to drip out of the orifice when the high tension field is not established.
  • the liquid spouts and flows according to Poiseuilles law in the form of a stream which sprays at a certain distance from the mouth, the explosion occurring prior to the jet meeting the surface to be coated.
  • the orifice is at such a distance from the electrode in contact with the liquid to be projected that no disruptive discharge occurs between the two electrodes when the field is established.
  • the field is produced by the high voltage source the potential of which is comprised between 10,000 and 100,000 volts, said field being adjustable to a suitable value in order to comply with the electrodynamic qualities of the liquid and the fiow according to Poiseuilles law.
  • the electrode. which is to be in contact with the liquid body is introduced in the axis of the insulating nozzle out of which the liquid to be projected drips when the high tension field is not established.
  • the electrode instead of introducing into the nozzle the electrode adapted to be in contact with the liquid, the electrode, according to another embodiment of the invention may be constituted by a metal mounting which supports the insulating nozzle, said mounting being in contact with the liquid.
  • This machine in addition to at least one of the devices.
  • nozzle or nozzles in question, comprises means for successively bringing in front of the. nozzle or nozzles the vessels to be varnished or coated, a reciprocating carriage adapted to cause the nozzle or nozzles to penetrate into the vessels and to come out therefrom, means for temporarily applying the high tension field, means for determining the supply of liquid to the nozzle or nozzles, and preferably a generalcontrol system for timing all said means.
  • Fig. 1 is a diagram illustrating a first embodiment of the device.
  • Fig. 1A shows a modification of this device.
  • Fig. 2 diagrammatically shows a second embodiment.
  • Fig. 2A shows a modification of the device of Fig. 2.
  • Fig. 3 is a diagram of the machine adapted for coating or varnishing the inner surface of vessels
  • Fig. 4 shows, with more details, the machine as a whole and, in therein.
  • the device comprises a nozzle 1 made of an insulating material such as glass, synthetic resins and notably the transparent synthetic resins (for instance that available under the trade name of Plexiglas), quartz, silica, porcelain, etc.
  • a nozzle 1 made of an insulating material such as glass, synthetic resins and notably the transparent synthetic resins (for instance that available under the trade name of Plexiglas), quartz, silica, porcelain, etc.
  • the orifice a volume of liquid of 0.20 to 0.40 cmfiper second approximately, which corresponds to one or two. drops per second, the head being at a pressure of 10,
  • small cylindrical tube 13 has is given the flow which corresponds to the quantity of liquid necessary in the time unit in order to obtain a layer of determined thickness over a determined area, there is also given the head which corresponds to the height of the constant level reservoir 3, there is also given the length which remains constant and the diameter of the tube is thereby determined, which constitutes the parameter of the hydrodynamic adjustment.
  • the carriage incorporated the advantage of permitting readily applying the Poiseuilles formula which, as it is known, gives the flow per unit of time in terms of the viscosity of the liquid, the length of the tube, its diameter and the head.
  • an electrode 4 connected to one of the poles of a source of adjustable high tension, either direct or alternating, said source being diagrammatically represented by the box 5.
  • the conducting surface 8 Positioned in front of the, orifice of thenozzle is the conducting surface 8 which is, grounded as at 9. The pole of the source. which is not connected to the electrode 4.is also grounded.
  • the jet being subjected to gravity is slightly bent toward the earth.
  • the length 10 first decreases until the tension reaches a maximum above which said length remains unchanged.
  • the two extreme aspects would be: either a jet without explosion, or a jet diverging from the exit 13 from the nozzle 1.
  • the length of the body of liquid comprised between the end of the electrode 4 and the orifice of the nozzle 1 is determined experimentally in such a manner that no disruptive discharge occurs between the electrode 4 and a receiving conducting surface 8, when the field is established.
  • This body of liquid has a function of self regulation in that, upon an excessive quantity of liquid being discharged out of the nozzle for instance owing to a variation of the potential, such liquid would be immediately replaced by a greater flow of liquid out of the reservoir 3.
  • the body of liquid therefore serves as a self regulator by means of variations of resistance.
  • a device of this kind has the advantage of lending it self, without any danger, to industrial purposes in spite of the high potential employed.
  • the current consumption is very low, for instance of the order of 50 microarnperes per orifice, and depends only on the fiow rate of the liquid which is proportional to the areas of the surfaces to be coated.
  • the device of Fig. 1A is similar to that of Fig. 1, with the difference that one of the poles of the high tension source 5 is connected to the conducting surface 8 whereas the electrode 4 is grounded.
  • Fig. 2 shows another embodiment of the device according to the invention. Like members are identified by like reference members.
  • this device it is the conducting surface 8 that is connected to the high potential of the source 5 through a brush 14.
  • One of the advantages consists in that any risk of dripping from the orifice of the nozzle is avoided, such drops are likely to initiate discharges if they are under a high potential.
  • the surface to be treated exerts an attraction upon the varnish, no drop maypossibly form at the exit from the nozzle.
  • this electrode is constituted by a metal mounting 15 in contact with the liquid.
  • This mounting holds the insulating nozzle 1 and is grounded as at 16. This construction is much more practical. Itv goes without. saying that, in this: case, the reforming the surface to be coated, it will be possible to 1 varnish or coat the inside of this vessel 17.
  • the electrode in contact with the liquid and the surface to bevarnished constitutes plates of a capacitor.
  • the disposition of Fig.2 corresponds merely to a superposition of the dielectrics inside the ca- 'pacitor.
  • Fig. 2A The only ditference' between Fig. 2 and Fig. 2A consists in that, in Fig. 2A, it is the electrode '15 that is connected to one pole of the source whereas the electrode 8 is grounded.
  • the insulating nozzle 1 is mounted in the metal cock 18, 1
  • the high potential source may be derived from a direct high tension system such as that diagrammatically shown as at 5 on Fig. 3.
  • the vessel 8. to be varnished internally is supportedv by insulating rollers 26 rotatably driven.
  • Fig. 4 shows a machine asv actually constructed: the rollers .21 of the carriage 19 roll. on the rails 27 bolted to the frame 30.
  • the movement of the carriage which carries the set of nozzles 1 is effected by the outer cam 31 which forms the edge of the plate 32 rigid with the shaft 29.
  • the nozzle 1 may be tilted by means of a horizontal bolt 34 and a lever terminated by a roller 35 in with the cam 31, effects through the medium of a switch 36 and relay 36 the application of the high tension onto the surface 8 through a slider 42. This surface remains alive during a predetermined time in response to the movement of the cam 25..
  • the varnish or emulsion is introduced into the set of nozzles, at the required moment in order to be subjected to the field, at a suitable moment of the rotational cycle so as to provide strictly the projection desired.
  • Apparatus for applying to a surface, a liquid having a dielectric constant between 1 and 5 and a resistivity above 1.44 ohms comprising at least one nozzle of insulating material having at the fore end thereof a nozzle orifice directed toward said surface, means for supplying said nozzle with a homogeneous and continuous body of said liquid at a pressure below that required to produce the flow of a continuous stream of liquid from said orifice, a first electrode associated with said nozzle and in contact with the liquid in said nozzle and a second electrode associated with said surface, means for applying a voltage of the order of 10,000 to 100,000 volts between said electrodes, said orifice being disposed centrally in the electric field between said electrodes and said first electrode being spaced rearwardly of said orifice in a direction away from said surface a distance greater than the arcing distance of the voltage applied between said electrodes, said electric
  • a method of transporting onto a surface a viscous liquid having a dielectric constant of the order of 1 to 5 and a resistivity not less than 1.44 10 ohms consisting in introducing a homogeneous and continuous body of said liquid into an insulating enclosure having a discharge orifice directed toward said surface, applying to the liquid in said enclosure a pressure sufficient to cause said liquid to flow to said orifice but insuflicient to produce the flow of a continuous stream of liquid from said orifice, establishing an electric field having a potential of 10,000 to 100,000 volts between a first electrode which is associated with said enclosure and in contact with said body of liquid and a second electrode which is associated with said surface, said first electrode being spaced rearwardly of said orifice in a direction away from said surface a distance greater than the arcing distance of the voltage applied between said electrodes, said electric field being of a magnitude to force a jet of liquid out of said orifice toward said surface and dispersing said jet into a spray before the liquid reaches said
  • a device such as claimed in claim 1, wherein the first electrode is connected to one pole of a high tension source the other pole of which is grounded and the second electrode also is grounded.
  • a device such as claimed in claim 1., wherein the first electrode is constituted by a metal mounting positioned at the end of the nozzle opposite the orifice thereof and at such a distance from said orifice: that no electrical discharge can take place between the electrode when the field is established.
  • Machine for coating the inner surface of vessels by means of a liquid the dielectric constant of which is comprised between 1 and 5 with a resistivity above l.44 10 ohms by using as a practically sole transport means, an electrical field produced by a high tension source the potential of which is comprised between 10,000 and 100,000 volts between two electrodes, comprising in combination at least one nozzle made of a material which does not conduct electricity, having at the fore end there of an orifice directed toward the inner surface of at least one of said vessels, supply means for supplying said nozzle with a homogeneous body of said liquid, a cock serving as an electrode secured to the nozzle at a certain distance from the orifice of said nozzle and making and interrupting the communication of said nozzle with the supply means, a further electrode connected to a conducting vessel having the shape of one of the vessels the inside of which is to be coated and receiving said vessel, a carriage carrying said nozzle, the cock and the supply means, means for reciprocating the carriage with respect to the vessel, means operative in time
  • Machine such as claimed in claim 9, furthermore comprising a switch and means operative in timed relation with the movements of the carriage and the operation of the cock for connecting or disconnecting the high tension source.
  • Machine such as claimed in claim 9, further comprising means cooperating with the nozzle in order to vary the inclinations of said nozzle in timed relation with the movements of the carriage.

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  • Electrostatic Spraying Apparatus (AREA)
US555999A 1950-10-13 1955-12-28 Method and apparatus for electrostatic coating utilizing projection of liquid solelyby the electric field Expired - Lifetime US2826513A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR2826513X 1950-10-13
FR1117341T 1955-01-07

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US (1) US2826513A (fr)
FR (2) FR1117341A (fr)
GB (1) GB793958A (fr)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3049301A (en) * 1959-12-13 1962-08-14 Escher Wyss Gmbh Electrostatic spraying of atomized material
US3122320A (en) * 1958-03-20 1964-02-25 Ford Motor Co Method for filling electrically charged receptacle
DE1299168B (de) * 1958-06-11 1969-07-10 Blanchard Andre Verfahren und Vorrichtung zum Zerstaeuben von polarem, fluessigem Brennstoff zur Speisung von Brennkraftmaschinen
US3495779A (en) * 1967-04-28 1970-02-17 Licentia Gmbh Electrostatic spray gun
US3626041A (en) * 1968-11-13 1971-12-07 Monsanto Co Apparatus and process for making continuous filament
US4002777A (en) * 1967-10-25 1977-01-11 Ransburg Corporation Method of depositing electrostatically charged liquid coating material
US4141698A (en) * 1976-06-01 1979-02-27 Advanced Mineral Research Ab Method of cleaning particle bearing gas
US4356528A (en) * 1976-07-15 1982-10-26 Imperial Chemical Industries Plc Atomization of liquids
US4455965A (en) * 1982-02-26 1984-06-26 Regie Nationale Des Usines Renault Automatic process and system for painting motor vehicle interiors
US4680163A (en) * 1984-04-14 1987-07-14 Kolbus Gmbh & Co. Kg Process and apparatus for sterilizing containers
US4900527A (en) * 1986-12-24 1990-02-13 Kolbus Gmbh & Co. Kg Appliance for sterilizing containers
US5049404A (en) * 1987-04-01 1991-09-17 Polaroid Corporation Method and apparatus for applying ultra-thin coatings to a substrate
EP1275440A1 (fr) * 2001-07-11 2003-01-15 Fuji Photo Film Co., Ltd. Dispositif et procédé de revêtement par pulvérisation électrostatique
US20050200982A1 (en) * 2003-12-24 2005-09-15 Cornwell James H. Enhanced beam antenna

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1416929A (en) * 1921-11-07 1922-05-23 William E Bailey Art of electrolysis
US1788600A (en) * 1924-02-07 1931-01-13 James S Smyser Abrasive article and manufacture of same
US2097233A (en) * 1934-03-31 1937-10-26 Research Corp Electrical deposition in pattern form
US2128327A (en) * 1936-12-23 1938-08-30 United States Pipe Foundry Method and apparatus for coating molds
US2187306A (en) * 1937-07-28 1940-01-16 Richard Schreiber Gastell Artificial thread and method of producing same
US2302185A (en) * 1940-07-27 1942-11-17 Union Oil Co Electrified spray apparatus
US2352252A (en) * 1941-10-31 1944-06-27 Westinghouse Air Brake Co Sanding control means
US2512743A (en) * 1946-04-01 1950-06-27 Rca Corp Jet sprayer actuated by supersonic waves
US2625590A (en) * 1948-07-31 1953-01-13 Vilbiss Co Means for electrostatically charging spray material
US2685536A (en) * 1944-09-29 1954-08-03 Ransburg Electro Coating Corp Method for electrostatically coating articles

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1416929A (en) * 1921-11-07 1922-05-23 William E Bailey Art of electrolysis
US1788600A (en) * 1924-02-07 1931-01-13 James S Smyser Abrasive article and manufacture of same
US2097233A (en) * 1934-03-31 1937-10-26 Research Corp Electrical deposition in pattern form
US2128327A (en) * 1936-12-23 1938-08-30 United States Pipe Foundry Method and apparatus for coating molds
US2187306A (en) * 1937-07-28 1940-01-16 Richard Schreiber Gastell Artificial thread and method of producing same
US2302185A (en) * 1940-07-27 1942-11-17 Union Oil Co Electrified spray apparatus
US2352252A (en) * 1941-10-31 1944-06-27 Westinghouse Air Brake Co Sanding control means
US2685536A (en) * 1944-09-29 1954-08-03 Ransburg Electro Coating Corp Method for electrostatically coating articles
US2512743A (en) * 1946-04-01 1950-06-27 Rca Corp Jet sprayer actuated by supersonic waves
US2625590A (en) * 1948-07-31 1953-01-13 Vilbiss Co Means for electrostatically charging spray material

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3122320A (en) * 1958-03-20 1964-02-25 Ford Motor Co Method for filling electrically charged receptacle
DE1299168B (de) * 1958-06-11 1969-07-10 Blanchard Andre Verfahren und Vorrichtung zum Zerstaeuben von polarem, fluessigem Brennstoff zur Speisung von Brennkraftmaschinen
US3049301A (en) * 1959-12-13 1962-08-14 Escher Wyss Gmbh Electrostatic spraying of atomized material
US3495779A (en) * 1967-04-28 1970-02-17 Licentia Gmbh Electrostatic spray gun
US4002777A (en) * 1967-10-25 1977-01-11 Ransburg Corporation Method of depositing electrostatically charged liquid coating material
US3626041A (en) * 1968-11-13 1971-12-07 Monsanto Co Apparatus and process for making continuous filament
US4141698A (en) * 1976-06-01 1979-02-27 Advanced Mineral Research Ab Method of cleaning particle bearing gas
US4381533A (en) * 1976-07-15 1983-04-26 Imperial Chemical Industries Plc Atomization of liquids
US4356528A (en) * 1976-07-15 1982-10-26 Imperial Chemical Industries Plc Atomization of liquids
US4476515A (en) * 1976-07-15 1984-10-09 Imperial Chemical Industries Plc Atomization of liquids
US4455965A (en) * 1982-02-26 1984-06-26 Regie Nationale Des Usines Renault Automatic process and system for painting motor vehicle interiors
US4680163A (en) * 1984-04-14 1987-07-14 Kolbus Gmbh & Co. Kg Process and apparatus for sterilizing containers
US4900527A (en) * 1986-12-24 1990-02-13 Kolbus Gmbh & Co. Kg Appliance for sterilizing containers
US5049404A (en) * 1987-04-01 1991-09-17 Polaroid Corporation Method and apparatus for applying ultra-thin coatings to a substrate
EP1275440A1 (fr) * 2001-07-11 2003-01-15 Fuji Photo Film Co., Ltd. Dispositif et procédé de revêtement par pulvérisation électrostatique
US20030029379A1 (en) * 2001-07-11 2003-02-13 Fuji Photo Film Co., Ltd. Electrostatic coating device and electrostatic coating method
US20050200982A1 (en) * 2003-12-24 2005-09-15 Cornwell James H. Enhanced beam antenna
US7221329B2 (en) * 2003-12-24 2007-05-22 James Henly Cornwell Enhanced beam antenna

Also Published As

Publication number Publication date
FR1117341A (fr) 1956-05-22
GB793958A (en) 1958-04-23
FR71269E (fr) 1959-11-02

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