Patent US4581145A successfully refreshed from Google Patents.
US4581145A
Expired / Lapsed
US
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Composition and method for inhibiting scale
Assignee: Veolia WTS USA Inc
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Filing: 1985-03-11
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Granted: 1986-04-08
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Expires: 2005-03-11
Abstract
Abstract The accumulation of scale in an aqueous system is inhibited by the addition of a composition comprising a copolymer of maleic acid or anhydride and vinyl sulfonic acid and an organic phosphonate such as aminotri(methylene phosphonic acid), hydroxyethylidene diphosphonic acid, or a water soluble salt thereof.
Inventors
- 👤 Dionisio G. Cuisia
- 👤 Chih M. Hwa
- 👤 Anne H. Kemp
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 10:17
CPC Classifications
C; C02; C02F; C02F5/00; C02F5/08; C02F5/10; C02F5/14
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
94 words
A composition for inhibiting formation of scale in an aqueous system comprising an aqueous solution of a composition comprising (a) a copolymer of maleic ahydride and vinyl sulfonic acid, said copolymer having a molecular weight of from about 6,000 to about 10,000 and a vinyl sulfonic acid to maleic anhydride mole ratio of from about 1:1 to about 2:1, or a water soluble salt thereof; and (b) hydroxyethylidene-1,1-diphosphonic acid or aminotri(methylene phosphonic acid), or a water soluble salt thereof; said copolymer and said phosphonic acid being present in a weight ratio of about 1:1.
Claim 2
Dependent Claim
94 words
A composition for inhibiting formation of scale in an aqueous system comprising an aqueous solution of a composition comprising (a) a copolymer of maleic ahydride and vinyl sulfonic acid, said copolymer having a molecular weight of from about 6,000 to about 10,000 and a vinyl sulfonic acid to maleic anhydride mole ratio of from about 1:1 to about 2:1, or a water soluble salt thereof; and (b) hydroxyethylidene-1,1-diphosphonic acid or aminotri(methylene phosphonic acid), or a water soluble salt thereof; said copolymer and said phosphonic acid being present in a weight ratio of about 1:1.
Claim 3
Independent Claim
123 words
A method of inhibiting formation of scale in a stream generating boiler comprising adding to the boiler water an aqueous solution of a composition comprising (a) a copolymer of maleic anhydride and vinyl sulfonic acid, said copolymer having a molecular weight of from about 6,000 to about 10,000 and a vinyl sulfonic acid to maleic anhydride mole ratio of from about 1:1 to 2:1, or a water soluble salt thereof; and (b) hydroxyethylidene-1,1-diphosphonic acid or aminotri(methylene phosphonic acid), or a water soluble salt thereof; said composition having a weight ratio of component (a) to component (b) of about 1:1 and being added to the boiler in an amount of from about 0.1 to about 50 parts per million of water in the boiler.
Claim 4
Independent Claim
123 words
A method of inhibiting formation of scale in a stream generating boiler comprising adding to the boiler water an aqueous solution of a composition comprising (a) a copolymer of maleic anhydride and vinyl sulfonic acid, said copolymer having a molecular weight of from about 6,000 to about 10,000 and a vinyl sulfonic acid to maleic anhydride mole ratio of from about 1:1 to 2:1, or a water soluble salt thereof; and (b) hydroxyethylidene-1,1-diphosphonic acid or aminotri(methylene phosphonic acid), or a water soluble salt thereof; said composition having a weight ratio of component (a) to component (b) of about 1:1 and being added to the boiler in an amount of from about 0.1 to about 50 parts per million of water in the boiler.
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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) | 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 |