US3490211A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High efficiency particulate air filter
Assignee: KEYSTONE FILTER MEDIA CO
•
Filing: 1967-07-31
•
Granted: 1970-01-20
•
Expires: 1987-07-31
Abstract
No abstract record available.
Inventors
- 👤 George T Cartier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:19
CPC Classifications
B; B01; B01D; B01D46/00; B01D46/52; B01D46/521; B01D46/523; B01D46/10; B01D46/12; B01D46/121; B01D2275/00; B01D2275/10
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
FR803101A
Cited
US2198190A
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FR932849A
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GB798765A
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US2980208A
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GB880427A
Cited
US3025963A
Cited
FR1275496A
Cited
US3248942A
Cited
US3158458A
Cited
US3222850A
Cited
US3252270A
Cited
US3273321A
Cited
US3372533A
Cited
US3402531A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-01-19 | 1973-07-21 | 1974-01-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-01-19 | 1977-07-21 | 1978-01-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-01-19 | 1981-07-21 | 1982-01-20 | $7700.00 | Window Closed / Lapsed |