US4432879A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Treatment of aqueous systems
Assignee: Grace Dearborn Ltd
•
Filing: 1981-08-28
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Granted: 1984-02-21
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Expires: 2001-08-28
Abstract
Abstract Sludge is dispersed in cooling water systems by means of a combination of 2-phosphonobutane-1,2,4-tricarboxylic acid and a water soluble organic polymer possessing carboxylic and sulfonate groups.
Inventors
- 👤 Brian Greaves
- 👤 Paul Ingham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 14:48
CPC Classifications
C; C02; C02F; C02F5/00; C02F5/08; C02F5/10; C02F5/14
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
89 words
Method of suspending sediment in cooling water systems that comprises adding thereto 2-phosphonobutane-1,2,4-tricarboxylic acid and a copolymer of methacrylic acid and 2-acrylamido-2-methylpropane sulfonic acid in a molar ratio of about 1:1 or a copolymer of styrene sulfonic acid and maleic acid in a molar ratio of about 3:1, said copolymer having a molecular weight of from about 4,000 to 6,000 and said 2-phosphonobutane-1,2,4-tricarboxylic acid and copolymer being added in a respective weight ratio of about 4:1 to 1:4 and in a total dosage of about 0.1 to 50 ppm.
Claim 2
Dependent Claim
89 words
Method of suspending sediment in cooling water systems that comprises adding thereto 2-phosphonobutane-1,2,4-tricarboxylic acid and a copolymer of methacrylic acid and 2-acrylamido-2-methylpropane sulfonic acid in a molar ratio of about 1:1 or a copolymer of styrene sulfonic acid and maleic acid in a molar ratio of about 3:1, said copolymer having a molecular weight of from about 4,000 to 6,000 and said 2-phosphonobutane-1,2,4-tricarboxylic acid and copolymer being added in a respective weight ratio of about 4:1 to 1:4 and in a total dosage of about 0.1 to 50 ppm.
Claim 3
Dependent Claim
21 words
Method according to claim 1 in which the copolymer is said copolymer of methacrylic acid/2 acrylamido 2 methyl propane sulfonic acid.
Claim 4
Dependent Claim
16 words
Method according to claim 2 in which the copolymer has a molecular weight of about 5,000.
Claim 5
Dependent Claim
19 words
Method according to claim 1 in which the copolymer is said copolymer of styrene sulfonic acid and maleic acid.
Claim 6
Dependent Claim
16 words
Method according to claim 4 in which the copolymer has a molecular weight of about 4,500.
Claim 7
Dependent Claim
23 words
Method according to claim 1 in which the 2-phosphonobutane-1,2,4-tricarboxylic acid and the copolymer are added in a respective weight ratio of about 1:1.
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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) | 1987-02-20 | 1987-08-22 | 1988-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-02-20 | 1991-08-22 | 1992-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-02-20 | 1995-08-22 | 1996-02-21 | $7700.00 | Window Closed / Lapsed |