Patent US4581074A successfully refreshed from Google Patents.
US4581074A
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US
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Method for cleaning internal heat transfer surfaces of boiler tubes
Assignee: VSESOJUZNY TEPLOTEKHNICHESKY NAUCHNO-ISSLEDOVATELSKY INSTITUT IMENI FE DZERZHINSKOGO USSR MOSCOW
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Filing: 1983-02-03
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Granted: 1986-04-08
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Expires: 2003-02-03
Abstract
Abstract A method for cleaning and removing iron oxide deposits from the internal heat transfer surfaces of boiler tubes, which consists in purging the tubes with superheated steam and oxygen driven at a speed of 20 to 80 m/sec. The oxygen content is 0.3 to 1.0 kg per ton of steam. The process both cleans and passivates the metal surfaces of the tubes.
Inventors
- 👤 Nadezhda N. Mankina
- 👤 Valentina Y. Kaplina
- 👤 Ivan A. Govorukhin
- 👤 Nikolai I. Gruzdev
- 👤 Jury E. Mishenin
- 👤 Nester I. Serebryannikov
- 👤 Boris S. Fedoseev
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 17:01
CPC Classifications
F; F28; F28G; F28G9/00; B; B08; B08B; B08B9/00; B08B9/02; B08B9/027; B08B9/032; B08B9/0321; B08B9/0328; C; C23; C23G; C23G5/00; B08B2230/00; B08B2230/01
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
98 words
A method for cleaning and removing iron oxide deposits from the internal heat transfer surfaces of metal boiler tubes comprising the steps of filling and purging the tubes with a mixture of superheated steam and oxygen driven at a speed of 20 to 80 m/sec, said mixture having an oxygen content of 0.3 to 1.0 kg per ton of steam, reacting said oxygen with the iron oxide deposits to loosen the latter, removing the loosened deposits from the tubes with the driven mixture, wherein said oxygen content simultaneously serves to passivate the metal surfaces of the boiler tubes.
Claim 2
Independent Claim
98 words
A method for cleaning and removing iron oxide deposits from the internal heat transfer surfaces of metal boiler tubes comprising the steps of filling and purging the tubes with a mixture of superheated steam and oxygen driven at a speed of 20 to 80 m/sec, said mixture having an oxygen content of 0.3 to 1.0 kg per ton of steam, reacting said oxygen with the iron oxide deposits to loosen the latter, removing the loosened deposits from the tubes with the driven mixture, wherein said oxygen content simultaneously serves to passivate the metal surfaces of the boiler tubes.
Claim 3
Dependent Claim
35 words
A method as claimed in claim 1, whereby said oxygen is obtained by feeding hydrogen peroxide to the inside of said boiler tubes in an amount of 0.6 to 2.0 kg per ton of steam.
Claim 4
Dependent Claim
34 words
A method as claimed in claim 1, whereby the temperature of the superheated steam and oxygen mixture is 170° C. to 450° C. and the purging is carried out for 1 to 5 hours.
Claim 5
Dependent Claim
34 words
A method as claimed in claim 2, whereby the temperature of the superheated steam and oxygen mixture is 170° C. to 450° C. and the purging is carried out for 1 to 5 hours.
References Cited (Backward Citations)
US1470359A
Cited
US3084076A
Cited
US3297481A
Cited
US3173874A
Cited
SU651189A1
Cited
US4282715A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-04-07 | 1989-10-07 | 1990-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-04-07 | 1993-10-07 | 1994-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-04-07 | 1997-10-07 | 1998-04-08 | $7700.00 | Window Closed / Lapsed |