US3451939A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Threshold compositions and methods
Assignee: Calgon Corp
•
Filing: 1966-04-13
•
Granted: 1969-06-24
•
Expires: 1986-04-13
Abstract
No abstract record available.
Inventors
- 👤 Paul H Ralston
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 12:19
CPC Classifications
C; C02; C02F; C02F5/00; C02F5/08; C02F5/10; C02F5/14; C02F5/145
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
US2575177A
Cited
GB667506A
Cited
US2599807A
Cited
US3135670A
Cited
US3099521A
Cited
US3288846A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-06-23 | 1972-12-23 | 1973-06-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-06-23 | 1976-12-23 | 1977-06-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-06-23 | 1980-12-23 | 1981-06-24 | $7700.00 | Window Closed / Lapsed |