US2468189A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Water purifying filter aid
Assignee: GREAT LAKES CARBON Corp
•
Filing: 1946-02-05
•
Granted: 1949-04-26
•
Expires: 1966-02-05
Abstract
No abstract record available.
Inventors
- 👤 Charles A Frankenhoff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:51
CPC Classifications
C; C02; C02F; C02F1/00; C02F1/52; C02F1/5236
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USRE20844E
Cited
US935695A
Cited
US1993761A
Cited
US2217466A
Cited
US2311713A
Cited
US2284827A
Cited
US2338958A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1952-04-25 | 1952-10-25 | 1953-04-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1956-04-25 | 1956-10-25 | 1957-04-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1960-04-25 | 1960-10-25 | 1961-04-26 | $7700.00 | Window Closed / Lapsed |