Patent US3438503A successfully refreshed from Google Patents.
US3438503A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rotary vacuum filter
Assignee: Carpco Res & Eng Inc
•
Filing: 1968-07-22
•
Granted: 1969-04-15
•
Expires: 1988-07-22
Abstract
No abstract record available.
Inventors
- 👤 James Hall Carpenter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 00:58
CPC Classifications
B; B01; B01D; B01D33/00; B01D33/15; B01D33/17; B01D33/58
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-04-14 | 1972-10-14 | 1973-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-04-14 | 1976-10-14 | 1977-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-04-14 | 1980-10-14 | 1981-04-15 | $7700.00 | Window Closed / Lapsed |