Patent US3904346A successfully refreshed from Google Patents.
US3904346A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrostatic powder coating process
Assignee: Individual
•
Filing: 1973-11-12
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Granted: 1975-09-09
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Expires: 1993-11-12
Abstract
Abstract A process of electrostatically coating cylindrical metal objects such as pipes with powdered resins is provided, in which the object is shot blasted, then subjected to high pressure fluid spray, e.g. water or steam jets, then heated above the fusion temperature of the resin, polarized and the resin powder sprayed on.
Inventors
- 👤 Leslie Earl Shaw
- 👤 Harold Francis Jarvis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:29
CPC Classifications
B; B05; B05D; B05D7/00; B05D7/14; B05D7/146; B05B; B05B14/00; B05B14/40; B05B14/41; B05B14/412; B05B16/00; B05B16/40; B05B16/405; B05B5/00; B05B5/08; B05B5/14; B05D1/00; B05D1/002; B05D1/02; B05D1/04; B05D1/06; B05D2401/00; B05D2401/30; B05D2401/32; B05D3/00; B05D3/002; Y; Y02; Y02P; Y02P70/00; Y02P70/10
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
87 words
An electrostatic process of coating a cylindrical metal object with powdered resin which includes the steps of shot blasting the object, causing the object to rotate about its axis, and whilst maintaining rotation of the object, sequentially subjecting the object to a high pressure water or steam spray, removing any residual moisture from the object, heating the object to a temperature which will fuse the powdered resin subsequently applied, polarizing the object, electrostatically spray coating the object with powdered resin and allowing the coated object to cool.
Claim 2
Dependent Claim
87 words
An electrostatic process of coating a cylindrical metal object with powdered resin which includes the steps of shot blasting the object, causing the object to rotate about its axis, and whilst maintaining rotation of the object, sequentially subjecting the object to a high pressure water or steam spray, removing any residual moisture from the object, heating the object to a temperature which will fuse the powdered resin subsequently applied, polarizing the object, electrostatically spray coating the object with powdered resin and allowing the coated object to cool.
Claim 3
Dependent Claim
22 words
The process of claim 1, wherein the high pressure spray is at a pressure of from about 1,000 to about 5,000 psi.
Claim 4
Dependent Claim
12 words
The process of claim 2 wherein the object is a steel pipe.
Claim 5
Dependent Claim
14 words
The process of claim 2 wherein the powdered resin material is an epoxy resin.
Claim 6
Dependent Claim
34 words
The process of claim 1, which also comprises feeding overspray powdered resin material from the spray coating step to a second spray coating station from which it is electrostatically spray coated onto the object.
Claim 7
Dependent Claim
14 words
The process of claim 1 wherein the powdered resin material is an epoxy resin.
Claim 8
Dependent Claim
29 words
The process of claim 6 wherein the object is a steel pipe, the pipe being heated to a temperature of from about 450*F to about 500*F prior to coating.
Claim 9
Dependent Claim
71 words
The process of claim 7 in which the step of rotating the pipe is accompanied by the step of advancing the rotating pipe so as to move it past a stationary cleaning station at which the shot blasting takes place, a water or steam spray station at which the pipe is sprayed, a heating station at which the pipe is heated and a coating station at which the pipe is coated.
Claim 10
Dependent Claim
77 words
The process of claim 8 in which the step of rotating and advancing the pipe is carried out by supporting the pipe on pairs of driven supporting wheels or rollers defining a trap for the pipe extending through said stations, the axis of said wheels or rollers being inclined to the direction of axial travel of the pipe, said wheels or rollers having friction surfaces which engage the pipe, and dipping into cold water as they rotate.
Claim 11
Dependent Claim
36 words
The process of claim 8, including the step of providing the pipe section with a heat barrier in the form of a solid plug inserted into the end thereof, prior to the rotation and advancement step.
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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) | 1978-09-08 | 1979-03-10 | 1979-09-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-08 | 1983-03-10 | 1983-09-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-08 | 1987-03-10 | 1987-09-09 | $7700.00 | Window Closed / Lapsed |