US3613993A
Expired / Lapsed
US
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Electrostatic painting method and apparatus
Assignee: Energy Innovations Inc
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Filing: 1968-10-28
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Granted: 1971-10-19
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Expires: 1988-10-28
Abstract
Abstract Apparatus and method for electrostatically charging a stream of atomized paint particles discharged from a spray gun. An emitter electrode is positioned in spaced relation to the end of the spray gun to establish a corona discharge from the electrode tip to a conductive portion of the gun end so that the direction of the discharge is opposite to the direction of flow of the particle stream. The apparatus may comprise an attachment unit for converting conventional spray guns to electrostatic spray guns, including a dielectric flow path-defining member downstream of the spray gun.
Inventors
- 👤 Meredith C Gourdine
- 👤 Edward L Collier
- 👤 Gerald P Lewis
- 👤 Harold Mccrae
- 👤 Donald H Porter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:45
CPC Classifications
B; B05; B05B; B05B5/00; B05B5/025; B05B5/053; B05B5/0533; B05B5/0535
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
50 words
Apparatus as defined in claim 1 wherein the spray head includes a spray nozzle for issuing the spray particles and wherein the corona discharge terminates at least in part at the spray nozzle and at least in part at the portion of the spray head immediately surrounding the spray nozzle.
Claim 2
Dependent Claim
106 words
Apparatus for charging particles of coating material comprising: a spray gun having an electrically conductive spray head for issuing a stream of particles, the spray head including at least one air horn for directing a jet of air toward the particle stream, an emitter electrode disposed downstream of and in spaced relation to the spray head, and means for establishing a corona discharge having its principal component extending upstream in the space between the emitter electrode and the spray head so that the corona discharge terminates at least in part at the air horn, whereby the particles pass through the corona discharge in opposed relation thereto.
Claim 3
Dependent Claim
93 words
Apparatus for charging particles of coating material comprising: a spray gun having an electrically conductive spray head for issuing a stream of particles, an elongate needlelike emItter electrode positioned downstream of and in spaced relation to the spray head, the emitter electrode having a pointed tip disposed substantially on the longitudinal axis of the particle stream, and means for establishing a corona discharge having its principal component extending upstream in the space between the emitter electrode tip and the spray head, whereby the particles pass through the corona discharge in opposed relation thereto.
Claim 4
Dependent Claim
44 words
Apparatus in accordance with claim 4 wherein the spray head includes at least one air horn for directing a jet of air toward the particle stream and wherein the corona discharge is established at least in part between the emitter electrode and air horn.
Claim 5
Dependent Claim
38 words
Apparatus as defined in claim 4 wherein the spray head includes a spray nozzle for issuing the spray particles and wherein the corona discharge is established at least in part between the emitter electrode and the spray nozzle.
Claim 6
Dependent Claim
60 words
Apparatus in accordance with claim 4 wherein the emitter electrode is so disposed as to extend into the particle stream in the upstream direction at an angle of from about 30* to 60* with respect to the longitudinal axis of the particle stream so that the tip of the emitter electrode is directed at least partly toward the spray head.
Claim 7
Dependent Claim
28 words
Apparatus in accordance with claim 7, wherein the shank of the emitter electrode is bent along a predetermined radius of curvature to extend back toward the spray head.
Claim 8
Dependent Claim
23 words
Apparatus as defined in claim 8 wherein said predetermined radius of curvature is within the range of from one-sixteenth inch to three-eighths inch.
Claim 9
Dependent Claim
29 words
Apparatus as defined in claim 8 wherein the tip of the emitter electrode is spaced from the spray nozzle within the range of from one-fourth inch to one-half inch.
Claim 10
Dependent Claim
55 words
Apparatus in accordance with claim 4 wherein the emitter electrode is so disposed as to extend into the particle stream in the upstream direction at an acute angle with respect to the longitudinal axis of the particle stream so that the tip of the emitter electrode is directed at least partly toward the spray head.
Claim 11
Dependent Claim
44 words
Apparatus in accordance with claim 4 wherein the tip of the emitter electrode is directed at least partly toward the spray head, whereby the stream of particles issuing from the spray head is directed in opposition to the direction of the emitter electrode tip.
Claim 12
Dependent Claim
104 words
Apparatus for charging particles of coating material comprising: a spray gun having an electrically conductive spray head for issuing a stream of particles, an emitter electrode disposed downstream of and in spaced relation to the spray head, and means, including a high-potential power supply for maintaining the emitter electrode at a potential within the range of from 8 to 12 kilovolts and a conductor connecting the spray head to ground, for establishing a corona discharge having its principal component extending upstream in the space between the emitter electrode and the spray head, whereby the particles pass through the corona discharge in opposed relation thereto.
Claim 13
Dependent Claim
136 words
An electrostatic spray charging apparatus for attachment to a nonelectrostatic spray gun having an electrically conductive spray head for discharging a stream of particles comprising: a housing member composed of dielectric material, an elongate emitter electrode having a pointed tip carried by the housing member, means on the housing member for adjustably attaching the housing member to the nonelectrostatic gun to position the emitter electrode tip at a point spaced downstream from the spray head and substantially on the longitudinal axis of the spray stream, and means for maintaining a corona discharge between the tip of the emitter electrode and the spray head in a zone occupied by the particle stream, the corona discharge having its principal component extending in the upstream direction, whereby the spray particles pass through the corona discharge in opposed relation thereto.
Claim 14
Dependent Claim
69 words
An electrostatic charging apparaTus as defined in claim 14 wherein the corona discharge terminates in part at the portion of the spray head immediately surrounding the discharged stream of particles, and the means for maintaining the corona discharge between the emitter electrode tip and the spray head includes a high-potential power supply and a conductor attachable to the spray head for connecting the spray head to a reference potential.
Claim 15
Dependent Claim
22 words
Apparatus as defined in claim 15 wherein the power supply provides a potential within the range of from 8 to 12 kilovolts.
Claim 16
Dependent Claim
90 words
Apparatus as defined in claim 14 wherein the emitter electrode is bent along a predetermined radius of curvature to form first and second leg portions, the first leg portion being secured at its free end to the housing and extending therefrom in the downstream direction; the second leg portion extending in a direction having a substantial upstream component and having said pointed tip at its free end, whereby said pointed tip is directed generally in opposition to the particle flow direction when the housing is attached to the spray gun.
Claim 17
Dependent Claim
47 words
Apparatus as defined in claim 17 wherein the first leg portion of the emitter electrode is generally parallel with the longitudinal axis of the particle stream and wherein the angle subtended by the first and second leg portions is within the range of from 30* to 60*.
Claim 18
Dependent Claim
23 words
Apparatus as defined in claim 18 wherein said predetermined radius of curvature is within the range of from one-sixteenth inch to three-eighths inch.
Claim 19
Dependent Claim
41 words
Apparatus according to claim 14 wherein the emitter electrode includes an elongated member forming an angle of between about 30* and 60* with the longitudinal axis of the particle stream and having a tip portion located closest to the spray head.
Claim 20
Dependent Claim
146 words
Apparatus for charging particles of coating material comprising: a spray gun having an electrically conductive spray head for issuing a stream of particles, an elongated needlelike emitter electrode having a pointed tip, the tip being disposed substantially on the longitudinal axis of the particle stream in downstream spaced relation to the spray head, the emitter electrode further being disposed so as to extend into the particle stream in the upstream direction at an angle of from about 30* to 60* with respect to the longitudinal axis of the particle stream so that the tip of the emitter electrode is directed at least partly toward the spray head, and means for establishing a corona discharge having its principal component extending in the upstream direction in the space between the emitter electrode and the spray head, whereby the particles pass through the corona discharge in opposed relation thereto.
Claim 21
Dependent Claim
135 words
In the method of electrostatically painting an object by means of a charged cloud of particles wherein paint is atomized upon being discharged from a spray head and formed into a particle spray stream in the presence of a high concentration of atmospheric ions, the improvement comprising the steps of: positioning the tip of an emitter electrode at a point substantially on the longitudinal axis of the particle spray stream and spaced downstream from the spray head, and establishing a potential difference between the emitter electrode tip and the spray head sufficient to maintain a corona discharge therebetween whose principal component is directed upstream through the portion of the particle spray stream between the electrode tip and the spray head, whereby the particles pass through the corona discharge in opposition to the principal component thereof.
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) | 1974-10-18 | 1975-04-19 | 1975-10-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-18 | 1979-04-19 | 1979-10-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-18 | 1983-04-19 | 1983-10-19 | $7700.00 | Window Closed / Lapsed |