Patent US5139494A successfully refreshed from Google Patents.
US2867429A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Calcination of alumina
Assignee: Dorr Oliver Inc
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Filing: 1957-03-25
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Granted: 1959-01-06
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Expires: 1977-03-25
Abstract
No abstract record available.
Inventors
- 👤 Thomas D Heath
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 20:01
CPC Classifications
C; C01; C01F; C01F7/00; C01F7/02; C01F7/44; C01F7/441; C01F7/445; B; B01; B01J; B01J6/00; B01J6/001; B01J6/004
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
113 words
IN A METHOD FOR THE FLUIDIZED TREATMENT OF FINELY DIVIDED ALUMINA HYDRATE WHICH INCLUDES THE STEPS OF PASSING SUCH ALUMINA HYDRATE PROGRESSIVELY THROUGH AT LEAST ONE PREHEATING BED, A CALCINING BED, AND A COOLING BED. SEPARATING ENTRAINED FINE SOLIDS INCLUDING PARTIALLY CALCINED FINE SOLIDS FROM FLUIDIZING GASES LEAVING THE PREHEATING BED, SAID SEPARATED SOLIDS BEING AT A TEMPERATURE SUBSTANTIALLY LOWER THAN THE TEMPERATURE OF SOLIDS IN THE CALCINING AND COOLING BEDS; THE IMPROVEMENT WHICH COMPRISES INTRODUCING A QUANTITY OF SAID SEPARATED SOLIDS INTO SAID COOLING BED IN AN AMOUNT SUFFICIENT TO EFFECT COOLING OF SOLIDS IN SUCH BED, BUT INSUFFICIENT TO COOL SOLIDS IN SUCH BED BELOW 800* F., THEREBY EFFECTING FURTHER CAL-
Claim 2
Dependent Claim
113 words
IN A METHOD FOR THE FLUIDIZED TREATMENT OF FINELY DIVIDED ALUMINA HYDRATE WHICH INCLUDES THE STEPS OF PASSING SUCH ALUMINA HYDRATE PROGRESSIVELY THROUGH AT LEAST ONE PREHEATING BED, A CALCINING BED, AND A COOLING BED. SEPARATING ENTRAINED FINE SOLIDS INCLUDING PARTIALLY CALCINED FINE SOLIDS FROM FLUIDIZING GASES LEAVING THE PREHEATING BED, SAID SEPARATED SOLIDS BEING AT A TEMPERATURE SUBSTANTIALLY LOWER THAN THE TEMPERATURE OF SOLIDS IN THE CALCINING AND COOLING BEDS; THE IMPROVEMENT WHICH COMPRISES INTRODUCING A QUANTITY OF SAID SEPARATED SOLIDS INTO SAID COOLING BED IN AN AMOUNT SUFFICIENT TO EFFECT COOLING OF SOLIDS IN SUCH BED, BUT INSUFFICIENT TO COOL SOLIDS IN SUCH BED BELOW 800* F., THEREBY EFFECTING FURTHER CAL-
References Cited (Backward Citations)
US2776132A
Cited
US2750258A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1962-01-05 | 1962-07-07 | 1963-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1966-01-05 | 1966-07-07 | 1967-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1970-01-05 | 1970-07-07 | 1971-01-06 | $7700.00 | Window Closed / Lapsed |