US3574555A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Radiation sensitive circuit for detecting combustible gas
Assignee: MSA Safety Inc
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Filing: 1969-09-26
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Granted: 1971-04-13
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Expires: 1989-09-26
Abstract
Abstract A PHOTOELECTRIC CELL IS FOCUSED ON THE CATALYTIC DETECTOR FILAMENT OF A COMBUSTIBLE GAS INDICATOR, IN WHICH A METER IS OPERATED BY CHANGES IN THE ELECTRICAL RESISTANCE OF THE FILAMENT. A NORMALLY OPEN AUXILIARY CIRCUIT ALSO IS CONNECTED WITH THE METER FOR OPERATING IT INDEPENDENTLY OF THE FILAMENT. WHENEVER THE FILAMENT GLOWS, WHICH CAUSES THE ELECTRICAL RESISTANCE OF THE PHOTOELECTRIC CELL TO CHANGE, CURRENT FLOWS THROUGH THE CELL TO CLOSE THE AUXILIARY CIRCUIT AND MAINTAIN IT CLOSED. D R A W I N G
Inventors
- 👤 Glenn H Fertig
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 16:15
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/14; G01N27/16
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) | 1974-04-12 | 1974-10-12 | 1975-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-12 | 1978-10-12 | 1979-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-12 | 1982-10-12 | 1983-04-13 | $7700.00 | Window Closed / Lapsed |