Patent US3552098A successfully refreshed from Google Patents.
US3552098A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Air filter control arrangement
Assignee: American Air Filter Co Inc
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Filing: 1968-07-12
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Granted: 1971-01-05
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Expires: 1988-07-12
Abstract
Abstract APPARATUS TO INDICATE THE CONDITION OF AIR FILTER MEDIA IN AN AIR FLOW CONDIUT AND TO CONTROL THE REPLACEMENT OF SUCH AIR FILTER MEDIA WHICH INCLUDES MEANS SENSITIVE TO CHANGE IN DIFFERENTIAL AIR PRESSURE BETWEEN THE UPSTREAM AND DOWNSTREAM SIDE OF THE MEDIA TO INDICATE THE CONDITION OF THE MEDIA, ADVANCE CONTROL MEANS TO ADVANCE A SELECTED LENGTH OF NEW MEDIA INTO THE AIR FLOW STREAM, AND SWITCH MEANS INTER-CONNECTED WITH THE FILTER MEDIA ADVANCE MEANS TO TERMINATE AIR FLOW THROUGH THE CONDUIT WHEN THE FILTER MEDIA IS CHANGED SO THERE IS NO DIFFERENTIAL PRESSURE ACROSS THE MEDIA AND THE DIFFERENTIAL PRESSURE SENSING MEANS IS RESET.
Inventors
- 👤 Thomas L Cochran
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:16
CPC Classifications
F; F24; F24F; F24F13/00; F24F13/28; F24F8/00; F24F8/10; F24F8/108
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-01-04 | 1974-07-06 | 1975-01-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-04 | 1978-07-06 | 1979-01-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-04 | 1982-07-06 | 1983-01-05 | $7700.00 | Window Closed / Lapsed |