US3693877A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrostatic spray coating apparatus
Assignee: Electrogasdynamics Inc
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Filing: 1970-05-06
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Granted: 1972-09-26
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Expires: 1990-05-06
Abstract
Abstract Improved methods and apparatus for charging atomized coating materials and maintaining an electrostatic depositing field in the electrostatic deposition of coating materials. Improved charging is effected by the selectively directed passage of corona discharge current from a primary source thereof through emitted coating material intermediate its point of emission and its locus of atomization to an electrically floating electrode element whose collection potential is maintained by a corona discharge emanating from an exposed end thereof.
Inventors
- 👤 Philip L Cowan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:08
CPC Classifications
B; B05; B05B; B05B5/00; B05B5/025; B05B5/053; B05B5/0531; B05B5/03; B05B5/035
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
285 words
In a fluid spray coating system wherein the coating fluid is atomized by interaction with a gaseous medium, an improved construction for electrically charging the atomized fluid spray and maintaining an electrostatic depositing field therefor, comprising an atomizing nozzle assembly defining a point of emission of a coherent fluid stream and an externally adjacent locus of atomization therefor, insulating means defining a channel disposed in surrounding relation to said locus of atomization and through which the fluid moves after release from the point of emission thereof, a primary corona discharge electrode element mounted in said insulating means and having an exposed terminal end portion extending into said channel intermediate the point of fluid emission and the point of complete atomization thereof, an electrically floating electrode element mounted in said insulating means having a first exposed terminal end portion in said channel and selectively positioned in relatively close proximity with the exposed terminal end portion of said primary corona discharge electrode element so as to preferentially direct fluid traversing current flow thereto from said exposed end portion of said primary corona discharge electrode element and in a direction substantially transverse to the direction of fluid flow through said channel, and having a second exposed terminal end portion positioned so that the distance to the nearest electrical ground is not less than 10% of the distance between said terminal end portion and a workpiece being coated and adapted to dissipate energy as a corona discharge emanating therefrom of a like polarity to that emanating from said exposed terminal end portion of said primary corona discharge electrode element for maintaining a continuous flow of current between said primary corona discharge electrode element and said electrically floating electrode element.
Claim 2
Dependent Claim
285 words
In a fluid spray coating system wherein the coating fluid is atomized by interaction with a gaseous medium, an improved construction for electrically charging the atomized fluid spray and maintaining an electrostatic depositing field therefor, comprising an atomizing nozzle assembly defining a point of emission of a coherent fluid stream and an externally adjacent locus of atomization therefor, insulating means defining a channel disposed in surrounding relation to said locus of atomization and through which the fluid moves after release from the point of emission thereof, a primary corona discharge electrode element mounted in said insulating means and having an exposed terminal end portion extending into said channel intermediate the point of fluid emission and the point of complete atomization thereof, an electrically floating electrode element mounted in said insulating means having a first exposed terminal end portion in said channel and selectively positioned in relatively close proximity with the exposed terminal end portion of said primary corona discharge electrode element so as to preferentially direct fluid traversing current flow thereto from said exposed end portion of said primary corona discharge electrode element and in a direction substantially transverse to the direction of fluid flow through said channel, and having a second exposed terminal end portion positioned so that the distance to the nearest electrical ground is not less than 10% of the distance between said terminal end portion and a workpiece being coated and adapted to dissipate energy as a corona discharge emanating therefrom of a like polarity to that emanating from said exposed terminal end portion of said primary corona discharge electrode element for maintaining a continuous flow of current between said primary corona discharge electrode element and said electrically floating electrode element.
Claim 3
Dependent Claim
53 words
The construction as set forth in claim 1 wherein said first exposed terminal end portion of said electrically floating electrode element extends into said channel and is shaped to produce a corona discharge of opposite electrical polarity from that emanating from said exposed terminal end portion of said primary corona discharge electrode element.
Claim 4
Dependent Claim
61 words
The construction as set forth in claim 1 wherein the exposed terminal end portion of said primary electrode element and the first exposed terminal end portion of the electrically floating electrode element extend into said channel for a limited distance so as to be out of the path of direct impingement with the major portion of the flow of fluid therepast.
Claim 5
Dependent Claim
38 words
The construction as set forth in claim 1 including gas operable electrogasdynamic power generating means disposed in proximity with said atomizing nozzle assembly and having its output voltage terminal electrically connected with said primary corona discharge electrode element.
Claim 6
Dependent Claim
67 words
The construction as set forth in claim 1 wherein said atomizing nozzle assembly is insulatingly spaced from a groundable base assembly and the second exposed terminal end portion of said floating electrode element is positioned relative to the nearest electrical ground such that the potential difference therebetween is substantially greater than the potential difference between said primary corona discharge electrode element and said electrically floating electrode element.
Claim 7
Dependent Claim
44 words
The construction as set forth in claim 1 wherein the second exposed terminal end portion of said floating electrode element is disposed downstream of the first exposed terminal end portion thereof and in proximity to the path of advance of the atomized coating material.
Claim 8
Dependent Claim
44 words
The construction as set forth in claim 1 wherein said first exposed terminal end portion of said floating electrode element is disposed in relatively close proximity with and in substantially diametrically opposed relation to the exposed terminal end portion of said primary electrode element.
Claim 9
Dependent Claim
227 words
In a fluid spray coating system wherein the coating fluid is atomized by interaction with a gaseous medium, an improved construction for electrically charging the atomized fluid spray and maintaining an electrostatic depositing field therefor, comprising an atomizing nozzle assembly defining a point of emission of a coherent fluid stream and an externally adjacent locus of atomization therefor, a primary corona discharge electrode element having a high potential exposed terminal end portion disposed in proximity to the point of fluid emission, an electrically floating electrode eLement having a first exposed corona discharge terminal end portion at a particle attracting potential relative to that of said exposed terminal end of said primary corona discharge electrode element positioned in proximity therewith so as to preferentially direct fluid traversing current flow therefrom in a direction substantially transverse to the direction of fluid flow, and having a second exposed terminal end portion positioned so that the distance to the nearest electrical ground is not less than 10% of the distance between said terminal end portion and a workpiece being coated and adapted to dissipate energy as a corona discharge emanating therefrom of a like polarity to that emanating from said exposed terminal end portion of said primary corona discharge electrode element for maintaining a continuous flow of current between said primary corona discharge electrode element and said electrically floating electrode element.
Claim 10
Dependent Claim
227 words
In a fluid spray coating system wherein the coating fluid is atomized by interaction with a gaseous medium, an improved construction for electrically charging the atomized fluid spray and maintaining an electrostatic depositing field therefor, comprising an atomizing nozzle assembly defining a point of emission of a coherent fluid stream and an externally adjacent locus of atomization therefor, a primary corona discharge electrode element having a high potential exposed terminal end portion disposed in proximity to the point of fluid emission, an electrically floating electrode eLement having a first exposed corona discharge terminal end portion at a particle attracting potential relative to that of said exposed terminal end of said primary corona discharge electrode element positioned in proximity therewith so as to preferentially direct fluid traversing current flow therefrom in a direction substantially transverse to the direction of fluid flow, and having a second exposed terminal end portion positioned so that the distance to the nearest electrical ground is not less than 10% of the distance between said terminal end portion and a workpiece being coated and adapted to dissipate energy as a corona discharge emanating therefrom of a like polarity to that emanating from said exposed terminal end portion of said primary corona discharge electrode element for maintaining a continuous flow of current between said primary corona discharge electrode element and said electrically floating electrode element.
Claim 11
Dependent Claim
158 words
In a fluid spray coating system wherein the coating fluid is atomized by interaction with a gaseous medium, an improved construction for electrically charging the atomized fluid spray comprising an atomizing nozzle assembly defining a point of emission of a coherent fluid stream and an externally adjacent locus of atomization therefor, a primary corona discharge electrode element having an exposed terminal end portion disposed in proximity to the point of fluid emission, at least one electrically floating electrode element disposed downstream of said exposed terminal end of said primary corona discharge electrode element and through which a major proportion of the current emanating from said primary corona discharge electrode element flows in series subsequent to traversal of the fluid stream substantially normal to the axis thereof, and wherein the potential difference between said floating electrode element and electrical ground is substantially greater than the potential difference between said floating electrode element and said primary corona discharge electrode element.
Claim 12
Dependent Claim
158 words
In a fluid spray coating system wherein the coating fluid is atomized by interaction with a gaseous medium, an improved construction for electrically charging the atomized fluid spray comprising an atomizing nozzle assembly defining a point of emission of a coherent fluid stream and an externally adjacent locus of atomization therefor, a primary corona discharge electrode element having an exposed terminal end portion disposed in proximity to the point of fluid emission, at least one electrically floating electrode element disposed downstream of said exposed terminal end of said primary corona discharge electrode element and through which a major proportion of the current emanating from said primary corona discharge electrode element flows in series subsequent to traversal of the fluid stream substantially normal to the axis thereof, and wherein the potential difference between said floating electrode element and electrical ground is substantially greater than the potential difference between said floating electrode element and said primary corona discharge electrode element.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-09-26 | 1976-03-27 | 1976-09-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-09-26 | 1980-03-27 | 1980-09-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-09-26 | 1984-03-27 | 1984-09-26 | $7700.00 | Window Closed / Lapsed |