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EP0178746A1 - Système dispensateur de matériaux de revêtement - Google Patents

Système dispensateur de matériaux de revêtement Download PDF

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Publication number
EP0178746A1
EP0178746A1 EP85303610A EP85303610A EP0178746A1 EP 0178746 A1 EP0178746 A1 EP 0178746A1 EP 85303610 A EP85303610 A EP 85303610A EP 85303610 A EP85303610 A EP 85303610A EP 0178746 A1 EP0178746 A1 EP 0178746A1
Authority
EP
European Patent Office
Prior art keywords
coating material
target
ring
sleeve
electrode
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP85303610A
Other languages
German (de)
English (en)
Inventor
Edward W. Drum
Gunther Fleig
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ransburg Corp
Original Assignee
Ransburg Corp
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 Ransburg Corp filed Critical Ransburg Corp
Publication of EP0178746A1 publication Critical patent/EP0178746A1/fr
Withdrawn legal-status Critical Current

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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
    • B05B5/04—Discharge apparatus, e.g. electrostatic spray guns characterised by having rotary outlet or deflecting elements, i.e. spraying being also effected by centrifugal forces
    • B05B5/0403—Discharge apparatus, e.g. electrostatic spray guns characterised by having rotary outlet or deflecting elements, i.e. spraying being also effected by centrifugal forces characterised by the rotating member
    • 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

Definitions

  • This invention relates to coating material application systems, and more particularly to systems in which the deposition of atomized coating material particles on a target to be coated is aided by an electric charge created on the atomized coating material particles.
  • the high-voltage supplies used for these applications are not designed to maintain high voltages across their terminals under conditions of heavy current load, for reasons of safety. Therefore, it is virtually impossible with such high-voltage supplies to maintain an acceptable potential on the atomizing device to insure an adequate charge on the atomized coating material particles to achieve the highest possible transfer efficiency of coating material between the atomizing device and the target.
  • That portion of the coating material handling system which is connected to the atomizer has to be isolated from ground potential. If a single source of coating material, for example, a single coating material color, is to be dispensed, it is ordinarily possible to isolate the paint supply electrically from ground potential.
  • Voltage block an intermediate reservoir between a high-volume coating material supply and the coating material dispensing device.
  • the voltage block is refilled either intermittently or continuously from the supply, which can be maintained at ground potential.
  • the intermediate reservoir itself is insulated from ground and typically resides at an intermediate potential or at the same potential as the dispensing device to which it is coupled. Steps are taken to see that no current flows from the intermediate reservoir back to the high-volume supply.
  • Voltage blocks of various types are known from, for example, Fortin U.S. Patent 1,655,262; Silsby, Jr. U.S. Patent 2,673,232; Peterson U.S. Patent 3,098,890; Uline et al U.S.
  • an apparatus and method are provided for spraying water-base paints, and other electrically highly conductive paints, such as metallic paints and paints in other highly-conductive vehicles and solvents.
  • the invention is also useful with the recently developed solvent-based high-solids coating materials in which solvents of extremely high polarity and electrical conductivity are used.
  • the method and apparatus permit the high color-change speeds and broad color selection required by, for example, automotive coating material application lines, without the need for voltage blocks or similar types of equipment.
  • a system for coating a target with coating material in which a potential difference is maintained between the target and particles of coating material which are dispensed to coat the target includes a dispensing device for finely dividing a stream of coating material to form the coating material particles.
  • the system further includes means for coupling the device to a source of coating material, a partition, an electrode located on the side of the partition opposite the side on which the dispensing device is located, and a power supply for maintaining between the target and the electrode an electrical potential of a sufficiently high magnitude to create and maintain a potential difference between the finely divided particles of coating material and the target.
  • the partition is constructed at least partly from a material having a relatively higher dielectric strength than the environment surrounding the dispensing device to reduce the likelihood of electrical discharge between the dispensing device and the electrode.
  • the partition is constructed at least partly from a resinous material.
  • means are provided for maintaining the dispensing device substantially at a neutral, or ground, potential.
  • the partition is generally cylindrical and surrounds the dispensing device.
  • the cylindrical partition is open at one end through which the dispensing device dispenses the finely divided coating material particles, and at the other end through which support means support the dispensing device in spaced orientation to the target.
  • the electrode comprises means providing an electrically conductive ring extending around an outside surface of the cylindrical partition.
  • the electrode comprises one or more electrically conductive discharge points extending from the ring generally toward the target.
  • the forward-most surface, the forward termination, of the ring faces in a first direction toward the target and the rearward termination of the ring faces rearward in a second and opposite direction away from the target.
  • the cylindrical partition has a forward termination closer to the target than the forward termination of the ring in the first direction, and a rearward termination further from the target than the rearward termination of the ring in the second direction.
  • the distance from the forward termination of the ring to the forward termination of the partition is substantially the same as the distance from the rearward termination of the ring to the rearward termination of the partition.
  • this distance is substantially greater than the distance from the forward termination of the ring to the rearward termination of the ring.
  • the dispensing device comprises a rotary atomizer and means for spinning the rotary atomizer at a rate sufficient to generate the finely divided coating material particles.
  • the generally cylindrical partition surrounding the rotary atomizer has an axis extending generally parallel to the axis of rotation of the rotary atomizer, and the ring is substantially coaxial with the axis of rotation of the rotary atomizer.
  • the generally cylindrical partition, or sleeve has a generally circular cross-section perpendicular to its axis
  • the ring has a generally circular cross-section perpendicular to the sleeve axis.
  • the ring has generally circular cross-sections generally parallel to the sleeve axis.
  • means are provided for feeding additional streams of multiple different selected coating materials to the rotary atomizer, and for selectively controlling which of the different coating materials is flowing to the rotary atomizer at a given time.
  • a stream of coating material is finely divided to form coating material particles, a partition is provided, an electrode is provided on the side of the partition opposite the side on which the coating material is finely divided, and a potential difference is maintained between a target to be coated and the electrode.
  • the potential difference is sufficiently high in magnitude to establish and maintain a potential difference between the finely divided particles of coating material and the target, so that electrical forces of repulsion exist between the electrode and the finely divided particles and electrical forces of attraction exist between the finely divided particles and the target.
  • the partition is constructed from a material having a relatively higher dielectric strength than the environment surrounding the dispensing device to reduce the likelihood of electrical discharge between the dispensing device and the electrode.
  • FIG. 1 An exit end view of a typical paint booth for applying a selected color of coating material from a number of available coating materials to an automobile body is illustrated in Fig. 1.
  • Three atomizing and dispensing devices 10, 12, 14, which may be generally of the type described in U.S. Patent 4,275,838, are assigned primary responsibility for dispensing coating material onto the right side 16 of a vehicle body 18, three devices 20, 22, 24 are assigned primary responsibility for dispensing coating material onto the left side 26 of the vehicle body 18, and three devices 28, 30, 32 are assigned primary responsibility for dispensing coating material onto the top 34 of the vehicle 18.
  • devices 28, 30, 32 are moumted on reciprocators 36 so that the devices 28, 30, 32 follow the contours of the top 34 of the vehicle 18.
  • atomizing devices 10, 12, 14, 20, 22, 24, 28, 30, 32, reciprocators 36 and associated fluid, pneumatic and electrical connections are housed in enclosures 40 inside of a coating booth 42 through which a conveyor 44 extends.
  • the enclosure 42 is an elongated tunnel-like booth having an entry end into which the conveyor 44 conveys the articles to be coated, here vehicle bodies, and an exit end, illustrated in Fig. 1, from which the conveyor 44 conveys the coated vehicle bodies.
  • Provisions, including ceiling fans 46, filters 47, and a floor grate 48 are made for circulating air through the coating booth 42 to pull down undeposited coating material which has been atomized and dispensed by the dispensing devices 10, 12, 14, 20, 22, 24, 28, 30, 32. This overspray may be removed through a water wash trough beneath grate 48.
  • Dispensing device 10 is mounted from one end of a horizontal support 50, the other end of which can be pivotally or otherwise movably mounted within enclosure 40 to permit some vertical movement of .dispensing device 10 as it dispenses coating material onto the vehicle body 18 passing before it.
  • Dispensing device 10 and horizontal support 50 are connected to ground so that they are maintained at ground potential.
  • the system further includes a color manifold 58, illustrated fragmentarily.
  • Color manifold 58 includes a plurality of illustratively air-operated color valves, six, 60-65 of which are shown. These color valves 60-65 control the flows of various selected colors of coating material from individual supplies into the color manifold 58.
  • a solvent valve 82 is located at the head 84 of color manifold 58.
  • a supply line 86 which is also maintained at ground potential, extends from the lower most portion 88 of color manifold 58 to a triggering valve 90 mounted adjacent dispensing device 10.
  • a feed tube 92 is attached to the output port of triggering valve 90. Feed tube 92 feeds a coating material flowing through a selected one of color valve 60-65 and manifold 58 into supply line 86 and into the interior of dispensing device 10. High-speed rotation of device 10 atomizes this selected color of coating material.
  • a line 97 extends from a pressurized source (not shown) of solvent through a valve 93 and a tube 95 to device 10.
  • Tube 95 feeds solvent into device 10 to remove any remaining amounts of the last color therefrom before dispensing of the next color begins.
  • a high-potential electrical supply 100 is provided.
  • Supply 100 may be of the type illustrated in, for example, U.S. Patent 3,875,892; U.S. Patent 3,851,618; U.S. Patent 3,894,272; U.S. Patent 4,075,677; U.S. Patent 4,187,527; or Woodruff U.S. Patent Application Serial No. 369,365, filed April 19, 1982, titled FOLD-BACK POWER SUPPLY, and assigned to the same assignee as this application.
  • a partition 102 in the form of a right circular cylindrical sleeve, the axis of which is coaxial with the axis of rotation of dispensing device 10 extends from adjacent the surface of the enclosure 40 to almost the forward atomizing edge 104 of the dispensing device 10.
  • the forward and rearward ends 106, 108, respectively of sleeve 102 are open to accommodate dispensing device 10 and horizontal support 50, respectively.
  • the inside wall 110 of sleeve 102 is provided with mounting posts 111.
  • the outside wall 112 of sleeve 102 is smooth and uninterrupted, with the exception that a plurality of standoffs 114 extend radially outward from the outer wall 112 and support from the outer wall l12 an electrode 116 in the form of a conductive ring.
  • the standoffs 114 support the wing 116 substantially equidistantly from the outside wall 112 of sleeve 102 at all points, so that the ring 116 is also coaxial with the axis of rotation of dispensing device 10.
  • the ring 116 is positioned at substantially the longitudinal center of sleeve 102 that is, substantially the same distance from forward end 106 and rearward end 108.
  • a high voltage cable 120 couples one terminal of the high potential supply 100 to ring 116.
  • the remaining output terminal of high potential supply 100 is coupled to ground.
  • Energization of the high potential supply 100 causes a continuous electrical discharge from the needle electrodes 118, and to a lesser extent generally from the ring 116.
  • the sleeve 102 which is constructed from a material having a relatively higher dielectric strength than the air surrounding the dispensing device 10, reduces the likelihood that this electrical discharge will find its way to ground through the grounded dispensing device 10, its associated support 50, or the grounded coating material and pneumatic supply lines connected to dispensing device 10.
  • sleeve 102 can be constructed from some resinous, i.e., plastic, material with an acceptably high dielectric strength.
  • the atomized coating material particles are dispensed from the atomizing edge 104 of device 10, they are projected generally radially outwardly from the axis of rotation of device 10. They are shielded from the electric field which is established and maintained between ring 116 and particularly needle electrodes 118 and the vehicle body 18 by the presence of the sleeve 102. However, after the particles pass radially outwardly beyond the open forward end 106 of sleeve 102, they are exposed to the electric field, and to the electrical discharge from the ring electrode 116 and particularly the needle electrodes 118. This electrical discharge causes charging of the atomized coating material particles.
  • the shielding effect of the higher dielectric strength sleeve 102 reduces substantially the likelihood of electrical discharge between the ring 116 with its needle electrodes l18 and any of the grounded components, such as device 10, support 50 and the various coating material and pneumatic connections to device 10.
  • the shielding effect of the higher dielectric strength sleeve 102 also permits the ring 116 to be made of a substantially smaller size, because of the reduced likelihood of electrical discharge between the ring and the device 10.
  • This reduction in the size of the ring 116 permits the devices 10 to be spaced very close together, as is frequently necessary for installations of the type including dispensing devices 28, 30, 32 in Fig. 1.
  • the smaller size of the rings 116 permits close spacing of such dispensing devices without interference between the ring associated with one dispensing device and the adjacent dispensing devices.
  • dispensing device 10 is grounded permits spraying closer to the surface of the vehicle body 18, since there is no danger of sparking between device 10 and body 18. Spraying from closer increases transfer efficiency and permits increased spray pattern control which enhances coating thickness uniformity and quality.

Landscapes

  • Application Of Or Painting With Fluid Materials (AREA)
  • Electrostatic Spraying Apparatus (AREA)
EP85303610A 1984-10-17 1985-05-22 Système dispensateur de matériaux de revêtement Withdrawn EP0178746A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US66158484A 1984-10-17 1984-10-17
US661584 1991-02-26

Publications (1)

Publication Number Publication Date
EP0178746A1 true EP0178746A1 (fr) 1986-04-23

Family

ID=24654220

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85303610A Withdrawn EP0178746A1 (fr) 1984-10-17 1985-05-22 Système dispensateur de matériaux de revêtement

Country Status (3)

Country Link
EP (1) EP0178746A1 (fr)
JP (1) JPS6197062A (fr)
ES (1) ES8608343A1 (fr)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0373749A1 (fr) * 1988-12-14 1990-06-20 Behr Industrial Equipment Inc. Système de revêtement par pulvérisation électrostatique
US4962724A (en) * 1987-08-14 1990-10-16 Sames S.A. Installation for spraying coating product, notably water-soluble paint
US4989793A (en) * 1990-02-02 1991-02-05 Illinois Tool Works, Inc. Indirect charging electrode for electrostatic spray guns
US5039019A (en) * 1990-08-01 1991-08-13 Illinois Tool Works, Inc. Indirect charging electrostatic coating apparatus
DE4126891A1 (de) * 1991-08-14 1993-02-18 Gema Volstatic Ag Elektrostatische pulver-spruehbeschichtungsanlage fuer automobil-karosserien
EP0618014A1 (fr) * 1993-04-01 1994-10-05 Sames S.A. Machine de projection de produit de revêtement par voie électrostatique
FR2703266A1 (fr) * 1993-04-01 1994-10-07 Sames Sa Machine de projection de produit de revêtement.
US7520450B2 (en) 2006-10-10 2009-04-21 Illinois Tool Works Inc. Electrical connections for coating material dispensing equipment

Citations (13)

* 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
US3279421A (en) * 1962-04-03 1966-10-18 Ransburg Electro Coating Corp Electrostatic spray coating systems
US3393662A (en) * 1964-12-30 1968-07-23 Ronald J. Blackwell Apparatus for electrostatic spray coating
US3408985A (en) * 1966-11-07 1968-11-05 Interplanetary Res & Dev Corp Electrostatic spray coating apparatus
DE2149170A1 (de) * 1970-10-22 1972-10-12 Tunzini Sames Anlagezum UEberziehen von Werkstuecken durch elektrostatisches Aufstaeuben
US3893620A (en) * 1973-10-04 1975-07-08 Desoto Inc Electrostatic atomization of conductive paints
US3934055A (en) * 1974-04-30 1976-01-20 Nordson Corporation Electrostatic spray method
US4020866A (en) * 1973-12-03 1977-05-03 The Gyromat Corporation Pressure vessel for voltage block material supply system
US4085892A (en) * 1976-04-21 1978-04-25 Dalton Robert E Continuously energized electrostatic coating voltage block
GB1558900A (en) * 1976-11-10 1980-01-09 Onoda Cement Co Ltd Method and apparatus for electrostatic powder coating
US4187527A (en) * 1976-08-09 1980-02-05 Ransburg Corporation Electrostatic coating system
US4275838A (en) * 1977-09-12 1981-06-30 Ransburg Corporation Rotating atomizing device
US4275834A (en) * 1978-01-11 1981-06-30 Akzo N.V. Process and apparatus for the electrostatic spraying of electrically conductive paint

Patent Citations (13)

* 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
US3279421A (en) * 1962-04-03 1966-10-18 Ransburg Electro Coating Corp Electrostatic spray coating systems
US3393662A (en) * 1964-12-30 1968-07-23 Ronald J. Blackwell Apparatus for electrostatic spray coating
US3408985A (en) * 1966-11-07 1968-11-05 Interplanetary Res & Dev Corp Electrostatic spray coating apparatus
DE2149170A1 (de) * 1970-10-22 1972-10-12 Tunzini Sames Anlagezum UEberziehen von Werkstuecken durch elektrostatisches Aufstaeuben
US3893620A (en) * 1973-10-04 1975-07-08 Desoto Inc Electrostatic atomization of conductive paints
US4020866A (en) * 1973-12-03 1977-05-03 The Gyromat Corporation Pressure vessel for voltage block material supply system
US3934055A (en) * 1974-04-30 1976-01-20 Nordson Corporation Electrostatic spray method
US4085892A (en) * 1976-04-21 1978-04-25 Dalton Robert E Continuously energized electrostatic coating voltage block
US4187527A (en) * 1976-08-09 1980-02-05 Ransburg Corporation Electrostatic coating system
GB1558900A (en) * 1976-11-10 1980-01-09 Onoda Cement Co Ltd Method and apparatus for electrostatic powder coating
US4275838A (en) * 1977-09-12 1981-06-30 Ransburg Corporation Rotating atomizing device
US4275834A (en) * 1978-01-11 1981-06-30 Akzo N.V. Process and apparatus for the electrostatic spraying of electrically conductive paint

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4962724A (en) * 1987-08-14 1990-10-16 Sames S.A. Installation for spraying coating product, notably water-soluble paint
EP0373749A1 (fr) * 1988-12-14 1990-06-20 Behr Industrial Equipment Inc. Système de revêtement par pulvérisation électrostatique
US4989793A (en) * 1990-02-02 1991-02-05 Illinois Tool Works, Inc. Indirect charging electrode for electrostatic spray guns
US5039019A (en) * 1990-08-01 1991-08-13 Illinois Tool Works, Inc. Indirect charging electrostatic coating apparatus
DE4126891A1 (de) * 1991-08-14 1993-02-18 Gema Volstatic Ag Elektrostatische pulver-spruehbeschichtungsanlage fuer automobil-karosserien
EP0618014A1 (fr) * 1993-04-01 1994-10-05 Sames S.A. Machine de projection de produit de revêtement par voie électrostatique
FR2703265A1 (fr) * 1993-04-01 1994-10-07 Sames Sa Machine de projection de produit de revêtement par voie électrostatique.
FR2703266A1 (fr) * 1993-04-01 1994-10-07 Sames Sa Machine de projection de produit de revêtement.
WO1994022590A1 (fr) * 1993-04-01 1994-10-13 Sames S.A. Machine de projection de produit de revetement
US5500045A (en) * 1993-04-01 1996-03-19 Sames S.A. Electrostatic spraying machine for coating products
US5772125A (en) * 1993-04-01 1998-06-30 Sames S.A. Machine for spraying a coating material
US7520450B2 (en) 2006-10-10 2009-04-21 Illinois Tool Works Inc. Electrical connections for coating material dispensing equipment

Also Published As

Publication number Publication date
ES8608343A1 (es) 1986-06-16
ES545943A0 (es) 1986-06-16
JPS6197062A (ja) 1986-05-15

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