US3535886A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of high purity nitrogen from air by distillation with depressurized,work expanded and cooled oxygen-rich bottoms used in indirect heat exchange for the distillation
Assignee: McDonnell Douglas Corp
•
Filing: 1967-07-05
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Granted: 1970-10-27
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Expires: 1987-07-05
Abstract
No abstract record available.
Inventors
- 👤 Michael L Hoffman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 18:33
CPC Classifications
F; F25; F25J; F25J3/00; F25J3/02; F25J3/04; F25J3/04248; F25J3/04284; F25J3/04624; F25J2200/00; F25J2200/02; F25J2230/00; F25J2230/52
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US1800353A
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US2753698A
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US2760351A
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US2713781A
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US2964913A
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US3264831A
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US3217502A
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US3358460A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-10-26 | 1974-04-27 | 1974-10-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-10-26 | 1978-04-27 | 1978-10-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-10-26 | 1982-04-27 | 1982-10-27 | $7700.00 | Window Closed / Lapsed |