US2921848A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fluidized-bed reduction of ore
Assignee: United States Steel Corp
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Filing: 1957-11-21
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Granted: 1960-01-19
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Expires: 1977-11-21
Abstract
No abstract record available.
Inventors
- 👤 Jagdish C Agarwal
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 13:11
CPC Classifications
C; C21; C21B; C21B13/00; C21B13/0033; Y; Y02; Y02P; Y02P10/00; Y02P10/10; Y02P10/134
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
139 words
IN A CONTINUOUS PROCESS FOR DIRECTLY REDUCING IRON OXIDE FINES IN A PRIMARY STEP SUBSTANTIALLY TO FEO AND IN A SECONDARY STEP PREDOMINANTLY TO METALLIC IRON, WHEREIN ASCENDING CURRENTS OF PREHEATED REDUCING GAS FLUIDIZE AND REDUCE ALREADY PARTIALLY REDUCED FINES IN SAID SECONDARY STEP, ASCENDING CURRENTS OF OFF-GAS FROM SAID SECONDARY STEP FLUIDIZE AND PARTIALLY REDUCE PREHEATED FINES IN SAID PRIMARY STEP, AND OFF-GAS FROM SAID PRIMARY STEP IS REGENERATED AND RECYCLED IN THE PROCESS, AND WHEREIN RESISTANCE TO GAS FLOW THROUGH THE FINES CAUSES A PRESSURE DROP WHICH TENDS TO CAUSE AN INCREASE IN THE EXIT GAS VELOCITY FROM EACH STEP, A METHOD OF EQUALIZING THE EXIT VELOCITIES OF GAS FROM THE TWO STEPS COMPRISING BYPASSING 4 TO 30 PERCENT OF THE OFF-GAS FROM SAID SECONDARY STEP AROUND SAID PRIMARY STEP, AND REGENERATING AND RECYCLING THE BYPASSED GAS.
Claim 2
Dependent Claim
139 words
IN A CONTINUOUS PROCESS FOR DIRECTLY REDUCING IRON OXIDE FINES IN A PRIMARY STEP SUBSTANTIALLY TO FEO AND IN A SECONDARY STEP PREDOMINANTLY TO METALLIC IRON, WHEREIN ASCENDING CURRENTS OF PREHEATED REDUCING GAS FLUIDIZE AND REDUCE ALREADY PARTIALLY REDUCED FINES IN SAID SECONDARY STEP, ASCENDING CURRENTS OF OFF-GAS FROM SAID SECONDARY STEP FLUIDIZE AND PARTIALLY REDUCE PREHEATED FINES IN SAID PRIMARY STEP, AND OFF-GAS FROM SAID PRIMARY STEP IS REGENERATED AND RECYCLED IN THE PROCESS, AND WHEREIN RESISTANCE TO GAS FLOW THROUGH THE FINES CAUSES A PRESSURE DROP WHICH TENDS TO CAUSE AN INCREASE IN THE EXIT GAS VELOCITY FROM EACH STEP, A METHOD OF EQUALIZING THE EXIT VELOCITIES OF GAS FROM THE TWO STEPS COMPRISING BYPASSING 4 TO 30 PERCENT OF THE OFF-GAS FROM SAID SECONDARY STEP AROUND SAID PRIMARY STEP, AND REGENERATING AND RECYCLING THE BYPASSED GAS.
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) | 1963-01-18 | 1963-07-20 | 1964-01-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1967-01-18 | 1967-07-20 | 1968-01-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1971-01-18 | 1971-07-20 | 1972-01-19 | $7700.00 | Window Closed / Lapsed |