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US3491891A
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Assignee: Individual
•
Filing: 1967-09-25
•
Granted: 1970-01-27
•
Expires: 1987-09-25
Abstract
No abstract record available.
Inventors
- 👤 John Krizman Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:47
CPC Classifications
B; B01; B01D; B01D29/00; B01D29/44
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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GB902843A
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GB936777A
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FR1314475A
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US3212242A
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US3281513A
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US3365864A
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US3352423A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-01-26 | 1973-07-28 | 1974-01-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-01-26 | 1977-07-28 | 1978-01-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-01-26 | 1981-07-28 | 1982-01-27 | $7700.00 | Window Closed / Lapsed |