US3801869A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Booth for electrostatic powder painting with contact type electric field curtain
Assignee: Individual
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Filing: 1972-09-25
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Granted: 1974-04-02
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Expires: 1992-09-25
Abstract
Abstract A booth in which electrically charged particulate material is sprayed onto a workpiece having an opposite charge, so that the particles are electrostatically attracted to the workpiece, has all of its walls that confront the workpiece made of electrical insulating material. A grid-like arrangement of parallel, spaced apart electrodes, insulated from each other, extends across the entire area of every wall, parallel to a surface of the wall and in intimate juxtaposition thereto. Each electrode is connected with one terminal of an alternating high voltage source, every electrode with a different terminal than each of the electrodes laterally adjacent to it, to produce a constantly varying field that electrodynamically repels particles from the wall.
Inventors
- 👤 S Masuda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 13:37
CPC Classifications
B; B05; B05B; B05B5/00; B05B5/08; B05B5/087; B05B5/088; B05B14/00; B05B14/40; B05B14/41; B05B14/412; B05B14/42; B05B7/00; B05B7/14; B05B7/1404; B05B7/1454; Y; Y02; Y02P; Y02P70/00; Y02P70/10; Y10; Y10S; Y10S55/00; Y10S55/46
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
260 words
A booth for electrostatic spray coating, having a zone at its interior at which a workpiece can be located, said booth being adapted for use with apparatus of the type comprising a nozzle that is directed toward said zone and from which particulate material to be coated onto the workpiece can issue, and means for impressing an electrical charge of one polarity upon particles of said material before they issue from the nozzle and for impressing upon the workpiece an opposite charge that tends to attract the particles to it electrostatically, said booth being characterized by: A. substantially all walls of the booth that are in confronting relation to said zone being of a material that is substantially an electrical nonconductor; B. a plurality of elongated electrodes distributed over substantially the entire area of a surface of each of said walls, said electrodes extending parallel to said surface and being in intimate juxtaposition thereto, and being in electrically insulated relation to one another, and substantial portions of the electrodes being in closely spaced parallel relation to one another and arranged alternately with one another in a regular sequence; C. means for connecting each of said electrodes with only one of the plural terminals of different polarity of a source of high alternating voltage, each electrode being connected with a terminal of said source that is different from the terminal to which each of its adjacent electrodes is connected, so that the several electrodes cooperate to produce a constantly varying electrical field by which charged particles are repelled from the walls.
Claim 2
Dependent Claim
260 words
A booth for electrostatic spray coating, having a zone at its interior at which a workpiece can be located, said booth being adapted for use with apparatus of the type comprising a nozzle that is directed toward said zone and from which particulate material to be coated onto the workpiece can issue, and means for impressing an electrical charge of one polarity upon particles of said material before they issue from the nozzle and for impressing upon the workpiece an opposite charge that tends to attract the particles to it electrostatically, said booth being characterized by: A. substantially all walls of the booth that are in confronting relation to said zone being of a material that is substantially an electrical nonconductor; B. a plurality of elongated electrodes distributed over substantially the entire area of a surface of each of said walls, said electrodes extending parallel to said surface and being in intimate juxtaposition thereto, and being in electrically insulated relation to one another, and substantial portions of the electrodes being in closely spaced parallel relation to one another and arranged alternately with one another in a regular sequence; C. means for connecting each of said electrodes with only one of the plural terminals of different polarity of a source of high alternating voltage, each electrode being connected with a terminal of said source that is different from the terminal to which each of its adjacent electrodes is connected, so that the several electrodes cooperate to produce a constantly varying electrical field by which charged particles are repelled from the walls.
Claim 3
Dependent Claim
143 words
The spray booth of claim 1, further characterized by: D. there being at least three of said electrodes distributed over the area of the bottom wall portions of said booth and alternating with one another in a regular sequence thereacross; and E. said means for connecting each of the last mentioned electrodes with a terminal of a high alternating voltage source providing for such connection of said electrodes with a multi-phase high alternating voltage source that there is a phase difference between every electrode and its laterally adjacent electrodes, so that the constantly varying electric field conjointly produced by all of said last mentioned electrodes has a wave-like variation by which charged particles are both repelled from the inner surface of said bottom wall portions and urged along the wall in one direction transverse to said parallel portions of said last mentioned electrodes.
Claim 4
Dependent Claim
87 words
The spray booth of claim 2 wherein all of said bottom wall portions are inclined to the horizontal and slope downwardly in said one direction so that the force of gravity tends to supplement the effect of the constantly varying electric field in transporting the particles in said one direction, further characterized by: F. collecting means having an inlet adjacent to the lowest edge portions of said wall portions and into which particles can fall after being transported along said wall portions, to be available for re-use.
Claim 5
Dependent Claim
122 words
The spray booth of claim 3, wherein bottom wall portions of the spray booth are porous, further characterized by: G. means for directing a flow of pressurized gas upwardly through said porous bottom wall portions and into the interior of the spray booth; H. filter means external to the spray booth, for filtering particles of said material out of gas in which they are entrained; and I. passage defining means having an inlet communicated with the interior of the spray booth near the top thereof and having an outlet opening to said filter means, for conducting to the filter means gas that has flowed upwardly through the spray booth from said porous bottom wall portions, together with particles entrained in such gas.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-04-01 | 1977-10-01 | 1978-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-04-01 | 1981-10-01 | 1982-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-04-01 | 1985-10-01 | 1986-04-02 | $7700.00 | Window Closed / Lapsed |