US2440487A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Corrosion resistant filter
Assignee: AT&T Inc
•
Filing: 1943-09-04
•
Granted: 1948-04-27
•
Expires: 1963-09-04
Abstract
No abstract record available.
Inventors
- 👤 Vincent A Rayburn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 17:34
CPC Classifications
B; B01; B01J; B01J19/00; B01J19/0053; B01J19/0073; B01D; B01D29/00; B01D29/11; B01D29/13; B01D29/15; B01D29/50; B01D29/52; B01D35/00; B01D35/12; B01D35/30; B01J19/02; B01D2201/00; B01D2201/04; B01D2201/043; B01D2201/0438; B01J2219/00; B01J2219/02; B01J2219/025
Claims Analysis
Total Claims: 0
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1951-04-27 | 1951-10-27 | 1952-04-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1955-04-27 | 1955-10-27 | 1956-04-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1959-04-27 | 1959-10-27 | 1960-04-27 | $7700.00 | Window Closed / Lapsed |