US3684720A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Removal of scale from surfaces
Assignee: Western Company of North America
•
Filing: 1970-03-06
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Granted: 1972-08-15
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Expires: 1990-03-06
Abstract
Abstract A METHOD OF REMOVING SCALE FOR SURFACES SUCH AS PIPING AND OTHER EQUIPMENT BY TREATING THE SCALE WITH A SOLUTION CONTAINING A SCALE CONVERTING AGENT AND A CHELATING AGENT. THE SCALE CONVERTING AGENT WILL IONIZE THE SCALE MATERIAL AND THE CHELATING AGENT WILL SEQUESTER IONS OF THE SCALE VERY RAPIDLY. FOR EXAMPLE, WHEN REMOVING CALCIUM SULFATE SCALE, THE TREATING SOLUTION CAN CONTAIN AMMONIUM BICARBONATE AS A SCALE CONVERTING AGENT AND A DI- OR TRIAMMONIUM SALT OF ETHYLENE-DIAMINE TETRAACETIC ACID AS THE CHELATING AGENT.
Inventors
- 👤 Darwin W Richardson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 05:13
CPC Classifications
C; C02; C02F; C02F5/00; C02F5/08; C02F5/10; C02F5/12; C09; C09K; C09K8/00; C09K8/52; C09K8/528; Y; Y10; Y10S; Y10S507/00; Y10S507/927
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-15 | 1976-02-14 | 1976-08-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-15 | 1980-02-14 | 1980-08-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-15 | 1984-02-14 | 1984-08-15 | $7700.00 | Window Closed / Lapsed |