US3941562A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Corrosion inhibition
Assignee: Calgon Corp
•
Filing: 1973-06-04
•
Granted: 1976-03-02
•
Expires: 1993-06-04
Abstract
Abstract Use of low molecular weight polymer and phosphate compositions to inhibit the corrosion of metals by oxygen-bearing waters.
Inventors
- 👤 William Robert Hollingshad
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 09:55
CPC Classifications
C; C23; C23F; C23F11/00; C23F11/08
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
48 words
A method of inhibiting the corrosion of metals in a water system which comprises maintaining in the water of said system at least about 10 ppm of a composition comprising a polyacrylamide having a molecular weight of from about 500 to about 10,000 and a source of orthophosphate.
Claim 2
Independent Claim
48 words
A method of inhibiting the corrosion of metals in a water system which comprises maintaining in the water of said system at least about 10 ppm of a composition comprising a polyacrylamide having a molecular weight of from about 500 to about 10,000 and a source of orthophosphate.
Claim 3
Dependent Claim
22 words
A method as in claim 1 wherein the ratio of polymer to phosphate is from about 20:1 to about 1:1 by weight.
Claim 4
Dependent Claim
22 words
A method as in claim 2 wherein the ratio of polymer to phosphate is from about 5:1 to about 2:1 by weight.
Claim 5
Dependent Claim
10 words
A method as in claim 1 which further contains zinc.
Claim 6
Dependent Claim
20 words
A method as in claim 1 which further comprises a member selected from the group consisting of benzotriazole and mercaptobenzothiazole.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-03-02 | 1979-09-01 | 1980-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-03-02 | 1983-09-01 | 1984-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-03-02 | 1987-09-01 | 1988-03-02 | $7700.00 | Window Closed / Lapsed |