US3956164A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Chelating agents
Assignee: Calgon Corp
•
Filing: 1974-09-23
•
Granted: 1976-05-11
•
Expires: 1994-09-23
Abstract
Abstract Combination of ethylenediaminetetraacetic acid and nitrilotriacetic acid or water soluble salts thereof for the removal and prevention of scale in steam generators.
Inventors
- 👤 Jerry Lee Walker
- 👤 Thomas Edward Cornelius, III
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 05:00
CPC Classifications
C; C02; C02F; C02F5/00; C02F5/08; C02F5/10; C02F5/12
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
51 words
The method of preventing and removing deposits from the metal surfaces of the aqueous circuit of steam generators by adding to the circulating water or to the feedwater an effective amount of a composition consisting essentially of a blend of approximately a 1:1 molar ratio of nitrilotriacetic acid and ethylenediaminetetraacetic acid.
Claim 2
Independent Claim
51 words
The method of preventing and removing deposits from the metal surfaces of the aqueous circuit of steam generators by adding to the circulating water or to the feedwater an effective amount of a composition consisting essentially of a blend of approximately a 1:1 molar ratio of nitrilotriacetic acid and ethylenediaminetetraacetic acid.
Claim 3
Dependent Claim
19 words
The method of claim 1 in which the nitrilotriacetic acid and ethylenediaminetetraacetic acid are present as the sodium salts.
Claim 4
Dependent Claim
31 words
The method of claim 2 in which the composition also contains dispersing agent in a concentration sufficient to result in from 1 to 100 mg/1 of dispersive in the boiler water.
Claim 5
Dependent Claim
31 words
The method of claim 2 in which the composition also contains an antifoam in a concentration sufficient to result in from 1 to 100 mg/1 of antifoam in the boiler water.
Claim 6
Dependent Claim
19 words
The composition of claim 8 in which the nitrilotriacetic acid and ethylenediaminetetraacetic acid are present as the sodium salts.
Claim 7
Dependent Claim
32 words
The composition of claim 5 in which the composition also contains a dispersing agent in a concentration sufficient to result in from 1 to 100 mg/1 of dispersive in the boiler water.
Claim 8
Dependent Claim
31 words
The composition of claim 5 in which the composition also contains an antifoam in a concentration sufficient to result in from 1 to 100 mg/1 of antifoam in the boiler water.
Claim 9
Dependent Claim
28 words
A scale preventive composition consisting essentially of a blend of nitrilotriacetic acid and ethylenediaminetetraacetic acid wherein the molar ratio of nitrilotriacetic acid to ethylenediaminetetraacetic acid is approximately 1:1.
Claim 10
Dependent Claim
28 words
A scale preventive composition consisting essentially of a blend of nitrilotriacetic acid and ethylenediaminetetraacetic acid wherein the molar ratio of nitrilotriacetic acid to ethylenediaminetetraacetic acid is approximately 1:1.
References Cited (Backward Citations)
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US3099521A
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US3151084A
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US3308065A
Cited
US3296027A
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US3549538A
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US3527609A
Cited
US3666664A
Cited
US3804770A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-05-11 | 1979-11-10 | 1980-05-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-05-11 | 1983-11-10 | 1984-05-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-05-11 | 1987-11-10 | 1988-05-11 | $7700.00 | Window Closed / Lapsed |