US3521864A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for controlling oxygen transfer and power requirements in a water aeration system
Assignee: WELLES PRODUCTS CORP
•
Filing: 1967-09-20
•
Granted: 1970-07-28
•
Expires: 1987-09-20
Abstract
No abstract record available.
Inventors
- 👤 Donald P Welles Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:41
CPC Classifications
C; C02; C02F; C02F3/00; C02F3/02; C02F3/12; C02F3/14; C02F3/16; C02F3/165; B; B01; B01F; B01F23/00; B01F23/20; B01F23/23; B01F23/234; B01F23/2342; B01F23/23421; B01F27/00; B01F27/80; B01F33/00; B01F33/50; B01F33/503; Y; Y02; Y02W; Y02W10/00; Y02W10/10; Y10; Y10S; Y10S261/00; Y10S261/75
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
CA637457A
Cited
US1526596A
Cited
US1867824A
Cited
US2063301A
Cited
US2521396A
Cited
US2827268A
Cited
US2865618A
Cited
US3154601A
Cited
US3207314A
Cited
US3320160A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-07-27 | 1974-01-26 | 1974-07-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-07-27 | 1978-01-26 | 1978-07-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-07-27 | 1982-01-26 | 1982-07-28 | $7700.00 | Window Closed / Lapsed |