Patent US3902855A successfully refreshed from Google Patents.
US3902855A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multi-stage countercurrent recrystallizer column having slip valve between each stage
Assignee: Dow Chemical Co
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Filing: 1973-04-02
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Granted: 1975-09-02
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Expires: 1993-04-02
Abstract
Abstract Acrylamide which is essentially free of crosslinking impurities is obtained by multiple recrystallizations from water solution wherein the mother liquor from each recrystallization is used as the aqueous medium in the preceding recrystallization. A unitary apparatus for carrying out the process is described.
Inventors
- 👤 Edward J Lynch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 13:23
CPC Classifications
B; B01; B01D; B01D9/00; B01D9/0004; B01D9/0013; B01D9/004
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
137 words
A COUNTERCURRENT RECRYSTALLIZER COLUMN COMPRISING AN ELONGATED CYLINDERICAL HOUSING DEFINING A PLURALITY OF SERIALLY CONNECTED CHAMBERS OF ABOUT EQUAL VOLUNE SEPARATED BY DIVIDEING PARTITIONS, EACH OF SAID PARTITIONS HAVING A BORE ADAPTED TO RECEIVE A SHAFT, SAID BORES BEING AXIALLY ALIGNED IN SAID HOUSING, A ROTATABLE SHAFT PASSING THROUGH THE BORES, STIRRING MEANS ATTACHED TO THE SHAFT IN EACH CHAMBER, LIQUID FLOW VALVE MEANS COMMUNICATING BETWEEN ADJACENT CHAMBERS, MEANS FOR WITHDRAWING LIQUID FROM EACH END CHAMBER, AND MEANS FOR INTRODUCING LIQUID INTO EACH END CHAMBER, AND A SINGLE HEAT-EXCHANGING JACKET SUBSTANTIALLY CLOSURE SAID SERIES OF CHAMBERS, SAID LIQUID FLOW VALVE MEANS BEING A SLIP VALVE DEFINED BY THE JUNCTION OF SAID SHAFT AND THE BORE IN EACH DIVIDER PARTITION, THE PORTION OF SAID SHAFT AT SAID JUNCTURE BEING LARGER THAN A PORTION OF SAID SHAFT IMMEDIATELY ADJACENT
Claim 2
Dependent Claim
137 words
A COUNTERCURRENT RECRYSTALLIZER COLUMN COMPRISING AN ELONGATED CYLINDERICAL HOUSING DEFINING A PLURALITY OF SERIALLY CONNECTED CHAMBERS OF ABOUT EQUAL VOLUNE SEPARATED BY DIVIDEING PARTITIONS, EACH OF SAID PARTITIONS HAVING A BORE ADAPTED TO RECEIVE A SHAFT, SAID BORES BEING AXIALLY ALIGNED IN SAID HOUSING, A ROTATABLE SHAFT PASSING THROUGH THE BORES, STIRRING MEANS ATTACHED TO THE SHAFT IN EACH CHAMBER, LIQUID FLOW VALVE MEANS COMMUNICATING BETWEEN ADJACENT CHAMBERS, MEANS FOR WITHDRAWING LIQUID FROM EACH END CHAMBER, AND MEANS FOR INTRODUCING LIQUID INTO EACH END CHAMBER, AND A SINGLE HEAT-EXCHANGING JACKET SUBSTANTIALLY CLOSURE SAID SERIES OF CHAMBERS, SAID LIQUID FLOW VALVE MEANS BEING A SLIP VALVE DEFINED BY THE JUNCTION OF SAID SHAFT AND THE BORE IN EACH DIVIDER PARTITION, THE PORTION OF SAID SHAFT AT SAID JUNCTURE BEING LARGER THAN A PORTION OF SAID SHAFT IMMEDIATELY ADJACENT
References Cited (Backward Citations)
US2034615A
Cited
US2034969A
Cited
US2587293A
Cited
US2862797A
Cited
US2816822A
Cited
US3013780A
Cited
US3192126A
Cited
US3687636A
Cited
US3607392A
Cited
US3681932A
Cited
US3762880A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-01 | 1979-03-03 | 1979-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-01 | 1983-03-03 | 1983-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-01 | 1987-03-03 | 1987-09-02 | $7700.00 | Window Closed / Lapsed |