Patent US2693456A successfully refreshed from Google Patents.
US2693456A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Treatment of diatomaceous earth
Assignee: Eagle Picher Co
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Filing: 1950-09-11
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Granted: 1954-11-02
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Expires: 1970-09-11
Abstract
No abstract record available.
Inventors
- 👤 John E Fennell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 15:51
CPC Classifications
B; B01; B01J; B01J20/00; B01J20/02; B01J20/10; B01J20/14
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
56 words
THE METHOD OF IMPROVING THE FILTERING QUALITIES OF DIATOMACEOUS EARTH, WHICH METHOD COMPRISES SUBJECTING THE DIATOMACEOUS EARTH TO A TEMPERATURE SUFFICIENTLY HIGH TO EFFECT ITS CALCINATION WHILE THE DIATOMACEOUS EARTH IS IN ADMIXTURE WITH APPROXIMATELY 20 TO 50% BY WEIGHT OF NATURALLY ADSORBED FREE WATER AND APPROXIMATELY 4 TO 8% BY WEIGHT OF A FLUXING AGENT.
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) | 1957-11-01 | 1958-05-03 | 1958-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-11-01 | 1962-05-03 | 1962-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-11-01 | 1966-05-03 | 1966-11-02 | $7700.00 | Window Closed / Lapsed |