US4658761A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Treatment of boiler tubes
Assignee: Individual
•
Filing: 1984-11-15
•
Granted: 1987-04-21
•
Expires: 2004-11-15
Abstract
Abstract The invention relates to the protection of metal boiler tubes from corrosion and erosion. Accordingly, the invention provides a metal boiler tube whereof at least a selected part of its surface is initially porous and whereof the initially porous surface has been coated with at least one stable metal oxide by the aplication to the porous surface of a solution containing salts or oxides of such metals followed by the conversion of such salts or treatment of such oxides of metals to attach the stable metal oxides to the porous surface.
Inventors
- 👤 Alain J. Duggan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 04:03
CPC Classifications
F; F22; F22B; F22B37/00; F22B37/02; F22B37/04; C; C23; C23C; C23C4/00; C23C4/18; F28; F28F; F28F19/00; F28F19/02; F28F19/06; Y; Y10; Y10S; Y10S122/00; Y10S122/13
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
65 words
A metal boiler tube having an outer layer of metal and metal oxide formed by metal spraying which is resistant to corrosion under the conditions to which the boiler tube is subjected in use; said layer being impregnated by at least chromium oxide by the application to the layer of a solution containing salts of chromium followed by conversion of such salts to chromium oxide.
Claim 2
Dependent Claim
65 words
A metal boiler tube having an outer layer of metal and metal oxide formed by metal spraying which is resistant to corrosion under the conditions to which the boiler tube is subjected in use; said layer being impregnated by at least chromium oxide by the application to the layer of a solution containing salts of chromium followed by conversion of such salts to chromium oxide.
Claim 3
Dependent Claim
21 words
A metal boiler tube according to claim 1 which has been coated by a series of applications and conversions or treatments.
Claim 4
Dependent Claim
14 words
A metal boiler tube according to claim 1 which is made of mild steel.
Claim 5
Dependent Claim
14 words
A metal boiler tube according to claim 1 which is made of alloy steel.
Claim 6
Dependent Claim
22 words
A boiler tube according to claim 1 in which the selected surface is roughened by treating it with acids or by grit-blasting.
Claim 7
Dependent Claim
33 words
A boiler tube according to claim 1 in which the outer layer of metal and metal oxide is selected from the group consisting of: nickel-chrome alloy, nickel-aluminide alloy and high chrome iron alloy.
Claim 8
Dependent Claim
25 words
A boiler tube according to claim 1 in which the outer layer of metal and metal oxide is provided by coating the tube with oxide.
Claim 9
Dependent Claim
31 words
A boiler tube according to claim 1 to which a phosphoric acid solution has been applied, and which has been heated to at least 300° C. after such phosphoric acid application.
Claim 10
Independent Claim
78 words
A method of protecting a metal boiler tube from erosion and corrosion comprising applying an outer layer of metal and metal oxide, which is resistant to erosion and corrosion under the conditions to which the boiler tube is subjected in use, by metal spraying and impregnating said outer layer with at least chromium oxide by the application to the outer layer of a solution containing salts of chromium oxide followed by conversion of such salts to chromium oxide.
Claim 11
Independent Claim
78 words
A method of protecting a metal boiler tube from erosion and corrosion comprising applying an outer layer of metal and metal oxide, which is resistant to erosion and corrosion under the conditions to which the boiler tube is subjected in use, by metal spraying and impregnating said outer layer with at least chromium oxide by the application to the outer layer of a solution containing salts of chromium oxide followed by conversion of such salts to chromium oxide.
Claim 12
Dependent Claim
19 words
A boiler tube according to claim 1 in which the outer layer is applied by means of combustion guns.
Claim 13
Dependent Claim
19 words
A boiler tube according to claim 1 in which the outer layer is applied by means of plasma guns.
Claim 14
Dependent Claim
19 words
A boiler tube according to claim 1 in which the outer layer is applied by means of detonation guns.
Claim 15
Dependent Claim
20 words
A boiler tube according to claim 1 in which the outer layer is applied by means of an electric arc.
Claim 16
Dependent Claim
21 words
A boiler tube according to claim 1 in which the outer layer is applied by means of a jet coat apparatus.
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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) | 1990-04-20 | 1990-10-20 | 1991-04-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-20 | 1994-10-20 | 1995-04-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-20 | 1998-10-20 | 1999-04-21 | $7700.00 | Window Closed / Lapsed |