US2854482A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the manufacture of urea
Assignee: Lonza Electric and Chemical Works Ltd
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Filing: 1956-11-19
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Granted: 1958-09-30
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Expires: 1976-11-19
Abstract
No abstract record available.
Inventors
- 👤 Guyer August
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 03:36
CPC Classifications
C; C07; C07C; C07C273/00; C07C273/02; C07C273/14; C07C273/16
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
58 words
A PROCESS FOR PURIFYING UREA SOLUTIONS CONTAINING BIURET AS AN IMPURITY, COMPRISING ESSENTIALLY TREATING THE BIURET-CONTAINING UREA SOLUTION WITH AMMONIA IN A CLOSED SYSTEM AT A TEMPERATURE OF FROM ABOUT 120-210*C. AND AT A PRESSURE OF FROM ABOUT 80 TO 350 ATMOSPHERES, WHEREBY THE BIURET CONTENT THEREIN IS REDUCED BY AMMONIATION, AND SEPARATING AMMONIA FROM THE PURIFIED SOLUTION.
Claim 2
Dependent Claim
58 words
A PROCESS FOR PURIFYING UREA SOLUTIONS CONTAINING BIURET AS AN IMPURITY, COMPRISING ESSENTIALLY TREATING THE BIURET-CONTAINING UREA SOLUTION WITH AMMONIA IN A CLOSED SYSTEM AT A TEMPERATURE OF FROM ABOUT 120-210*C. AND AT A PRESSURE OF FROM ABOUT 80 TO 350 ATMOSPHERES, WHEREBY THE BIURET CONTENT THEREIN IS REDUCED BY AMMONIATION, AND SEPARATING AMMONIA FROM THE PURIFIED SOLUTION.
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) | 1961-09-29 | 1962-03-31 | 1962-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-09-29 | 1966-03-31 | 1966-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-09-29 | 1970-03-31 | 1970-09-30 | $7700.00 | Window Closed / Lapsed |