Patent US3687622A successfully refreshed from Google Patents.
US3687622A
Expired / Lapsed
US
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High pressure purification of hydrogen fluoride
Assignee: EIDP Inc
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Filing: 1970-11-30
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Granted: 1972-08-29
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Expires: 1990-11-30
Abstract
Abstract ANHYDROUS HYDROGEN FLORIDE CONTAINING LESS THAN ABOUT 3000 PARTS PER BILLION OF ARSENIC IS PRODUCED BY DISTILLING INDUSTRIAL GRADE OR CRUDE HYDROGEN FLUORIDE AT A PRESSURE GREATER THAN 115 P.S.I.A. AT PRESSURES ABOVE 165 P.S.I.A., THE RESULTING HYDROGEN FLORIDE CONTAINS LESS THAN ABOUT 100 PARTS PER BILLION OF ARSENIC.
Inventors
- 👤 George James Garris
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:43
CPC Classifications
C; C01; C01B; C01B7/00; C01B7/19; C01B7/191; C01B7/195; C01B7/196
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-29 | 1976-02-28 | 1976-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-29 | 1980-02-28 | 1980-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-29 | 1984-02-28 | 1984-08-29 | $7700.00 | Window Closed / Lapsed |