Patent USRE20966E successfully refreshed from Google Patents.
Patent US3251879A successfully refreshed from Google Patents.
US3251879A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of low-biuret urea crystals
Assignee: Chemical Construction Corp
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Filing: 1963-06-19
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Granted: 1966-05-17
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Expires: 1983-06-19
Abstract
No abstract record available.
Inventors
- 👤 William J Rosenbloom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 13:52
CPC Classifications
C; C07; C07C; C07C273/00; C07C273/02; C07C273/14; C07C273/16; C05; C05C; C05C9/00; C05C9/005
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
86 words
A PROCESS FOR PRODUCTION OF SOLID CRYSTALLINE UREA OF LOW BIURET CONTENT WHICH COMPRISES CRYSTALLIZING SUBSTANTIALLY PURE UREA CRYSTALS FROM AN AQUEOUS SOLUTION CONTAINING DISSOLVED UREA AND BIURET, WITHDRAWING A FIRST SLURRY FROM SAID SOLUTION COMPRISING SOLID UREA CRYSTALS ENTRAINED IN MOTHER LIQUOR OF HIGH BIURET CONTENT, ELUTRIATING THE CRYSTALS IN SAID FIRST SLURRY BY PASSING SAID FIRST SLURRY INTO THE UPPER PORTION OF A CRYSTAL SETTLING ZONE COMPRISING A BODY OF QUEOUS UREA SOLUTION AND PASSING MAKE-UP AQUEOUS UREA SOLUTION OF LOW BIURET CONTENT INTO
Claim 2
Dependent Claim
86 words
A PROCESS FOR PRODUCTION OF SOLID CRYSTALLINE UREA OF LOW BIURET CONTENT WHICH COMPRISES CRYSTALLIZING SUBSTANTIALLY PURE UREA CRYSTALS FROM AN AQUEOUS SOLUTION CONTAINING DISSOLVED UREA AND BIURET, WITHDRAWING A FIRST SLURRY FROM SAID SOLUTION COMPRISING SOLID UREA CRYSTALS ENTRAINED IN MOTHER LIQUOR OF HIGH BIURET CONTENT, ELUTRIATING THE CRYSTALS IN SAID FIRST SLURRY BY PASSING SAID FIRST SLURRY INTO THE UPPER PORTION OF A CRYSTAL SETTLING ZONE COMPRISING A BODY OF QUEOUS UREA SOLUTION AND PASSING MAKE-UP AQUEOUS UREA SOLUTION OF LOW BIURET CONTENT INTO
References Cited (Backward Citations)
US2663731A
Cited
FR1127788A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1969-05-16 | 1969-11-15 | 1970-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-05-16 | 1973-11-15 | 1974-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-05-16 | 1977-11-15 | 1978-05-17 | $7700.00 | Window Closed / Lapsed |