Patent US4600524A successfully refreshed from Google Patents.
US4600524A
Expired / Lapsed
US
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Composition and method for inhibiting scale
Assignee: Veolia WTS USA Inc
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Filing: 1983-12-08
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Granted: 1986-07-15
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Expires: 2003-12-08
Abstract
Abstract The accumulation of scale in an aqueous system is inhibited by the addition of a copolymer of maleic acid or anhydride or fumaric acid and allyl sulfonic acid and a water soluble organic phosphonic acid such as aminotri(methylene phosphonic acid), ethylenediaminetetra(methylene phosphonic acid), hydroxyethylidene diphosphonic acid and 2-phosphonobutane tricarboxylic acid-1,2,4 or water soluble salts thereof. Scale can actually be removed by the addition of these materials to pressurized boiler water systems. Allyl or vinyl copolymers, a phosphonate, and optionally a water soluble, hardness precipitating agent such as a carbonate or a phosphate may be used when treating pressurized boilers to provide an in-service cleaning effect.
Inventors
- 👤 Dionisio G. Cuisia
- 👤 Chih M. Hwa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 17:38
CPC Classifications
C; C02; C02F; C02F5/00; C02F5/08; C02F5/10; C02F5/14
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
125 words
A composition for controlling scale in an aqueous steam generating boiler system comprising scale inhibiting amounts of a mixture consisting essentially of: (1) a copolymer of maleic acid and allyl sulfonic acid or a water soluble salt thereof, said copolymer having a molecular weight of from about 800 to about 25,000 and an allyl sulfonic acid to maleic acid mole ratio of about 1:3 to 3:1; (2) from about 0.25 to about 4 parts by weight, per part by weight of said copolymer or copolymer salt, of hydroxyethylidene-1,1-diphosphonic acid or a water soluble salt thereof; and (3) from about 500 to about 0.1 parts by weight, per part by weight of said copolymer or copolymer salt, of a water soluble sodium phosphate hardness precipitating agent.
Claim 2
Dependent Claim
125 words
A composition for controlling scale in an aqueous steam generating boiler system comprising scale inhibiting amounts of a mixture consisting essentially of: (1) a copolymer of maleic acid and allyl sulfonic acid or a water soluble salt thereof, said copolymer having a molecular weight of from about 800 to about 25,000 and an allyl sulfonic acid to maleic acid mole ratio of about 1:3 to 3:1; (2) from about 0.25 to about 4 parts by weight, per part by weight of said copolymer or copolymer salt, of hydroxyethylidene-1,1-diphosphonic acid or a water soluble salt thereof; and (3) from about 500 to about 0.1 parts by weight, per part by weight of said copolymer or copolymer salt, of a water soluble sodium phosphate hardness precipitating agent.
Claim 3
Dependent Claim
29 words
Composition as defined in claim 1 containing from about 15 to about 1.5 parts of sodium phosphate hardness precipitating agent per part by weight of copolymer or copolymer salt.
Claim 4
Dependent Claim
18 words
Composition as defined in claim 2 in which the weight ratio of (1) and (2) is about 1:1.
Claim 5
Dependent Claim
19 words
Composition as defined in claim 3 in which the allyl sulfonic acid to maleic acid ratio is about 1:1.
Claim 6
Dependent Claim
19 words
Composition as defined in claim 4 in which the copolymer has a molecular weight of about 1,000 to 15,000.
Claim 7
Dependent Claim
15 words
Composition as defined in claim 1 comprising an aqueous solution of (1), (2) and (3).
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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) | 1989-07-14 | 1990-01-13 | 1990-07-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-07-14 | 1994-01-13 | 1994-07-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-07-14 | 1998-01-13 | 1998-07-15 | $7700.00 | Window Closed / Lapsed |