Patent US4431547A successfully refreshed from Google Patents.
US4431547A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Use of acrylamide/acrylic acid copolymers for prevention of fouling by Ca3 (PO4)2
Assignee: ChampionX LLC
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Filing: 1982-12-08
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Granted: 1984-02-14
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Expires: 2002-12-08
Abstract
Abstract A copolymer consisting of a 3:1 ratio of acrylamide to acrylic acid with a molecular weight of approximately 10,000 is very effective in preventing calcium phosphate fouling of heat transfer surfaces as found, for example, in cooling water.
Inventors
- 👤 Leonard Dubin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 13:40
CPC Classifications
C; C02; C02F; C02F5/00; C02F5/08; C02F5/10; C02F5/12
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
63 words
A method of preventing the fouling of heat transfer surfaces in contact with industrial cooling waters which contain the fouling producing chemical calcium phosphate, which comprises treating such waters with from 1-50 ppm of acrylamide/acrylic acid copolymer having weight ratio of 3:1 and a molecular weight between 7,000-11,000, to stabilize and inhibit the formation of calcium phosphate, and to disperse particulate calcium phosphate.
Claim 2
Independent Claim
63 words
A method of preventing the fouling of heat transfer surfaces in contact with industrial cooling waters which contain the fouling producing chemical calcium phosphate, which comprises treating such waters with from 1-50 ppm of acrylamide/acrylic acid copolymer having weight ratio of 3:1 and a molecular weight between 7,000-11,000, to stabilize and inhibit the formation of calcium phosphate, and to disperse particulate calcium phosphate.
References Cited (Backward Citations)
US3463730A
Cited
US3699048A
Cited
US3663448A
Cited
US3890228A
Cited
US4008164A
Cited
US4029577A
Cited
US4361492A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-02-13 | 1987-08-15 | 1988-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-02-13 | 1991-08-15 | 1992-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-02-13 | 1995-08-15 | 1996-02-14 | $7700.00 | Window Closed / Lapsed |