US3616607A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Separation of nitrogen and methane containing gas mixtures
Assignee: Northern Natural Gas Co
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Filing: 1970-04-06
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Granted: 1971-11-02
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Expires: 1990-04-06
Abstract
Abstract A MEMBRANE DIFFUSION PROCESS FOR SELECTIVELY PERMEATING NITROGEN FROM A METHANE-NITROGEN CONTAINING MIXTURE TO OBTAIN ENRICHED SEPARATED FRACTIONS.
Inventors
- 👤 Donald L Klass
- 👤 Carl D Landahl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 19:09
CPC Classifications
B; B01; B01D; B01D71/00; B01D71/06; B01D71/40; B01D71/42; B01D71/421; B01D69/00; B01D69/12; C; C07; C07C; C07C7/00; C07C7/144
Claims Analysis
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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) | 1974-11-01 | 1975-05-03 | 1975-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-01 | 1979-05-03 | 1979-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-01 | 1983-05-03 | 1983-11-02 | $7700.00 | Window Closed / Lapsed |