US3054697A - Electrostatic painting - Google Patents
Electrostatic painting Download PDFInfo
- Publication number
- US3054697A US3054697A US11586A US1158660A US3054697A US 3054697 A US3054697 A US 3054697A US 11586 A US11586 A US 11586A US 1158660 A US1158660 A US 1158660A US 3054697 A US3054697 A US 3054697A
- Authority
- US
- United States
- Prior art keywords
- wires
- workpiece
- charging
- paint
- atomizing means
- 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.)
- Expired - Lifetime
Links
- 238000010422 painting Methods 0.000 title description 3
- 239000007788 liquid Substances 0.000 description 11
- 239000003973 paint Substances 0.000 description 7
- 230000005686 electrostatic field Effects 0.000 description 6
- 239000000443 aerosol Substances 0.000 description 5
- 238000000034 method Methods 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 238000009503 electrostatic coating Methods 0.000 description 2
- 230000001788 irregular Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
Images
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
- B05B5/08—Plant for applying liquids or other fluent materials to objects
- B05B5/087—Arrangements of electrodes, e.g. of charging, shielding, collecting electrodes
-
- 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
Definitions
- This invention relates to a process and apparatus for electrostatically coating workpieces with a liquid.
- This invention is more particularly concerned with a process and apparatus which will enable a uniform coating of liquid to be laid down upon a nonuniform surface of a workpiece by means of an electrostatic field.
- the particular object of this invention is to permit a uniform electrostatic coating to be applied to workpieces which present an uneven or irregular surface to the electrostatic field.
- the electrostatic coating of such irregular surfaces has in the past been unsatisfactory due to the tendency of the electrostatic field to shun declivities and preferentially to deposit paint on those portions of the workpieces which are electrostatically closest to the source of the aerosol.
- FIGURE of drawing is a schematic cross section of an apparatus usable in the practice of this invention.
- 11 is a perforated tube which serves to atomize and charge paint contained therein.
- a space of thirty inches was maintained between the liquid charging and atomizing means 11 (perforated tube) and the crests of the undulating workpiece 10.
- Wires 12 are arranged in the form of a grid and consist of a central section indicated by the letter V consisting of five wires and two outer sections of thirteen wires each, these wires being spaced apart two inches and preferably parallel to the workpiece and to each other.
- Liquid charging and atomizing means 11 (perforated tube) is maintained by any conventional means at a voltage of 150,000 volts negative with respect to the grounded workpiece 10.
- That portion of the wires 12 designated by the letter V is charged to a negative potential of 25,000 volts and the remaining 26 wires are Patented sept. 18, 1962 ice TABLE I Weight of Paint Deposited on Test Patches Original Final Gain in Position Weight, Weight Weight grams It has been found desirable to keep the potential on the grid wires 12 relatively great in order to reduce the tendency for paint to accumulate on them. If large deposits of paint are permitted to accumulate on the grid wires, the electric field existing between the wires and the sprayer will result in the formation on the wires of positively charged drops which will be carried back toward the sprayer ultimately to be deposited thereon, or to discharge a corresponding quantity of negatively charged droplets in flight. These will result in wastage of paint and interference with the operation of the system.
- the charge applied to wires 12 is preferably of the same polarity as liquid charging and atomizing means 11. However, this is not necessary. Under some circumstances Wires 12 may be charged to the opposite polarity with respect to charging and atomizing means 11. Alternatively, certain of the wires may have a potential negative to the workpiece and other wires a positive potential. Each individual painting setup must ordinarily be experimentally evaluated for the proper values of such parameters as voltages, wire diameter and wire spacing.
- the process of applying an approximately uniform coating of a liquid to a workpiece presenting a nonuniform surface comprising establishing a high potential between a liquid charging and atomizing means and the workpiece, positioning between the charging and atomizing means and the workpiece a plurality of wires and charging these wires to substantial potentials which are numerically less than the potential of the charging and atomizing means and of the same polarity, the potentials of these wires being adjusted to nonuniform values to establish a relatively uniform field intensity over the nonuniform surface of the workpiece, the wires closer to the workpiece being charged to a potential higher than the wires more remote from the workpiece.
Description
United states Patent 3,054,697 ELECTRGSTATIC PAINTING Max J. Irland, Dearhorn, and Allen H. Turner, Ann
Arbor, Mich., assignors to Ford Motor Company, Dearborn, Mich., a corporation of Delaware Fiied Feb. 29, 1960, Ser. No. 11,586 1 Claim. (Cl. 117-93) This invention relates to a process and apparatus for electrostatically coating workpieces with a liquid. This invention is more particularly concerned with a process and apparatus which will enable a uniform coating of liquid to be laid down upon a nonuniform surface of a workpiece by means of an electrostatic field.
The use of an electrostatic field to cause a precipitation of liquids and more particularly paint upon a workpiece has been common practice for many years and the art thereon is very voluminous. A factor common to all of these processes is the creation of an electrically charged aerosol of the liquid and propulsion and deposition of this aerosol upon the working piece by means of an electrostatic field.
The particular object of this invention is to permit a uniform electrostatic coating to be applied to workpieces which present an uneven or irregular surface to the electrostatic field. The electrostatic coating of such irregular surfaces has in the past been unsatisfactory due to the tendency of the electrostatic field to shun declivities and preferentially to deposit paint on those portions of the workpieces which are electrostatically closest to the source of the aerosol.
The sole FIGURE of drawing is a schematic cross section of an apparatus usable in the practice of this invention.
This invention can be most readily comprehended by a study of the figure of drawing which has been presented herewith. In this figure the numeral has been assigned to the workpiece. It is to be noted that workpiece 10 presents an undulating surface to the electrostatic field. Liquid charging and atomizing means 11 may be any of the conventional apparatus Well-known to the art for producing a charged aerosol. Wires 12 have been interposed between workpiece 10 and liquid charging and atomizing means 11. The sole purpose of wires 12 is to cause the aerosol to deposit in a layer of approximately uniform thickness upon undulating workpiece 10.
In the specific apparatus depicted in the figure of drawing, 11 is a perforated tube which serves to atomize and charge paint contained therein. A space of thirty inches was maintained between the liquid charging and atomizing means 11 (perforated tube) and the crests of the undulating workpiece 10. Wires 12 are arranged in the form of a grid and consist of a central section indicated by the letter V consisting of five wires and two outer sections of thirteen wires each, these wires being spaced apart two inches and preferably parallel to the workpiece and to each other. Liquid charging and atomizing means 11 (perforated tube) is maintained by any conventional means at a voltage of 150,000 volts negative with respect to the grounded workpiece 10. That portion of the wires 12 designated by the letter V is charged to a negative potential of 25,000 volts and the remaining 26 wires are Patented sept. 18, 1962 ice TABLE I Weight of Paint Deposited on Test Patches Original Final Gain in Position Weight, Weight Weight grams It has been found desirable to keep the potential on the grid wires 12 relatively great in order to reduce the tendency for paint to accumulate on them. If large deposits of paint are permitted to accumulate on the grid wires, the electric field existing between the wires and the sprayer will result in the formation on the wires of positively charged drops which will be carried back toward the sprayer ultimately to be deposited thereon, or to discharge a corresponding quantity of negatively charged droplets in flight. These will result in wastage of paint and interference with the operation of the system.
The charge applied to wires 12 is preferably of the same polarity as liquid charging and atomizing means 11. However, this is not necessary. Under some circumstances Wires 12 may be charged to the opposite polarity with respect to charging and atomizing means 11. Alternatively, certain of the wires may have a potential negative to the workpiece and other wires a positive potential. Each individual painting setup must ordinarily be experimentally evaluated for the proper values of such parameters as voltages, wire diameter and wire spacing.
We claim:
The process of applying an approximately uniform coating of a liquid to a workpiece presenting a nonuniform surface comprising establishing a high potential between a liquid charging and atomizing means and the workpiece, positioning between the charging and atomizing means and the workpiece a plurality of wires and charging these wires to substantial potentials which are numerically less than the potential of the charging and atomizing means and of the same polarity, the potentials of these wires being adjusted to nonuniform values to establish a relatively uniform field intensity over the nonuniform surface of the workpiece, the wires closer to the workpiece being charged to a potential higher than the wires more remote from the workpiece.
References Cited in the file of this patent UNITED STATES PATENTS 2,636,471 Starkey Apr. 28, 1953 2,716,380 Martin Aug. 30, 19,55
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11586A US3054697A (en) | 1960-02-29 | 1960-02-29 | Electrostatic painting |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11586A US3054697A (en) | 1960-02-29 | 1960-02-29 | Electrostatic painting |
Publications (1)
Publication Number | Publication Date |
---|---|
US3054697A true US3054697A (en) | 1962-09-18 |
Family
ID=21751066
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11586A Expired - Lifetime US3054697A (en) | 1960-02-29 | 1960-02-29 | Electrostatic painting |
Country Status (1)
Country | Link |
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US (1) | US3054697A (en) |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3255730A (en) * | 1962-02-26 | 1966-06-14 | Grohl Edmund | Device for the production of unicoloured and multicoloured tufted materials |
US3279253A (en) * | 1963-12-03 | 1966-10-18 | Douglas Aircraft Co Inc | Dielectrophoretic propellant orientation system |
US3336903A (en) * | 1963-04-24 | 1967-08-22 | Sames Sa De Machines Electrost | Electrostatic coating apparatus |
US3714928A (en) * | 1970-11-17 | 1973-02-06 | Mead Corp | Multiple jet channel |
US3900585A (en) * | 1972-02-12 | 1975-08-19 | Agency Ind Science Techn | Method for control of ionization electrostatic plating |
US4740384A (en) * | 1983-10-12 | 1988-04-26 | Basf Lacke & Farben Ag | Process and apparatus for applying two or more colors of paint |
WO1994022589A1 (en) * | 1993-04-07 | 1994-10-13 | Nordson Corporation | Method and apparatus for coating three dimensional articles |
US5741558A (en) * | 1993-04-07 | 1998-04-21 | Nordson Corporation | Method and apparatus for coating three dimensional articles |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2636471A (en) * | 1946-10-10 | 1953-04-28 | Ransburg Electro Coating Corp | Electrostatic coating apparatus |
US2716380A (en) * | 1953-11-02 | 1955-08-30 | Lithographic Technical Foundat | Spray dampening system for lithographic offset printing presses |
-
1960
- 1960-02-29 US US11586A patent/US3054697A/en not_active Expired - Lifetime
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2636471A (en) * | 1946-10-10 | 1953-04-28 | Ransburg Electro Coating Corp | Electrostatic coating apparatus |
US2716380A (en) * | 1953-11-02 | 1955-08-30 | Lithographic Technical Foundat | Spray dampening system for lithographic offset printing presses |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3255730A (en) * | 1962-02-26 | 1966-06-14 | Grohl Edmund | Device for the production of unicoloured and multicoloured tufted materials |
US3336903A (en) * | 1963-04-24 | 1967-08-22 | Sames Sa De Machines Electrost | Electrostatic coating apparatus |
US3279253A (en) * | 1963-12-03 | 1966-10-18 | Douglas Aircraft Co Inc | Dielectrophoretic propellant orientation system |
US3714928A (en) * | 1970-11-17 | 1973-02-06 | Mead Corp | Multiple jet channel |
US3900585A (en) * | 1972-02-12 | 1975-08-19 | Agency Ind Science Techn | Method for control of ionization electrostatic plating |
US4740384A (en) * | 1983-10-12 | 1988-04-26 | Basf Lacke & Farben Ag | Process and apparatus for applying two or more colors of paint |
WO1994022589A1 (en) * | 1993-04-07 | 1994-10-13 | Nordson Corporation | Method and apparatus for coating three dimensional articles |
US5741558A (en) * | 1993-04-07 | 1998-04-21 | Nordson Corporation | Method and apparatus for coating three dimensional articles |
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