Patent US1822573A successfully refreshed from Google Patents.
Patent US3169703A successfully refreshed from Google Patents.
US3169703A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cascade draft control
Assignee: HAGAN CONTROLS CORP
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Filing: 1960-06-27
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Granted: 1965-02-16
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Expires: 1980-06-27
Abstract
No abstract record available.
Inventors
- 👤 Lyle F Martz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 17:01
CPC Classifications
F; F23; F23N; F23N3/00; F23N3/06; F23N3/08; G; G05; G05D; G05D16/00; G05D16/20; G05D16/2093; G05D16/2095; F23N2233/00; F23N2233/02; F23N2235/00; F23N2235/02; F23N2235/04; F23N2235/06
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
144 words
APPARATUS FOR MAINTAINING A DESIRED PRESSURE IN A COMBUSTION CHAMBER HAVING AN EXHAUST DRAFT DUCT INCLUDING AN OBSTRUCTION WHICH CAUSED A PRESSURE DROP THEREIN COMPRISING: A FIRST PRESSURE TRANSDUCER FOR GENERATING AN ELECTRICAL SIGNAL REPRESENTING COMBUSTION CHAMBER PRESSURE,M A FIRST AMPLIFIER FOR GENERATING A BIAS SIGNAL REPRESENTING A VARIANCE BETWEEN SAID PRESSURE SIGNAL AND A SET POINT, SAID AMPLIFIER HAVING A FEEDBACK CIRCUIT COMPRISING A RESISTOR AND A CAPACITOR, A SECOND PRESSURE TRANSDUCER FOR GENERATING AN ELECTRICAL SIGNAL REPRESENTING PRESSURE AT A POINT DOWNSTREAM FROM THE PRESSURE DROP, A SECOND AMPLIFIER FOR GENERATING A CONTROL SIGNAL AS A FUNCTION OF THE DUCT PRESSURE BIASED BY A SET POINT REGULATED BY SAID BIAS SIGNAL, AND MEANS RESPONSIVE TO SAID CONTROL SIGNAL FOR POSITIONING AN AIR FLOW DEVICE AT A POINT DOWNSTREAM FROM THAT AT WHICH THE DUCT PRESSURE IS SENSED BY SAID SECOND PRESSURE TRANSDUCER.
Claim 2
Dependent Claim
144 words
APPARATUS FOR MAINTAINING A DESIRED PRESSURE IN A COMBUSTION CHAMBER HAVING AN EXHAUST DRAFT DUCT INCLUDING AN OBSTRUCTION WHICH CAUSED A PRESSURE DROP THEREIN COMPRISING: A FIRST PRESSURE TRANSDUCER FOR GENERATING AN ELECTRICAL SIGNAL REPRESENTING COMBUSTION CHAMBER PRESSURE,M A FIRST AMPLIFIER FOR GENERATING A BIAS SIGNAL REPRESENTING A VARIANCE BETWEEN SAID PRESSURE SIGNAL AND A SET POINT, SAID AMPLIFIER HAVING A FEEDBACK CIRCUIT COMPRISING A RESISTOR AND A CAPACITOR, A SECOND PRESSURE TRANSDUCER FOR GENERATING AN ELECTRICAL SIGNAL REPRESENTING PRESSURE AT A POINT DOWNSTREAM FROM THE PRESSURE DROP, A SECOND AMPLIFIER FOR GENERATING A CONTROL SIGNAL AS A FUNCTION OF THE DUCT PRESSURE BIASED BY A SET POINT REGULATED BY SAID BIAS SIGNAL, AND MEANS RESPONSIVE TO SAID CONTROL SIGNAL FOR POSITIONING AN AIR FLOW DEVICE AT A POINT DOWNSTREAM FROM THAT AT WHICH THE DUCT PRESSURE IS SENSED BY SAID SECOND PRESSURE TRANSDUCER.
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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) | 1968-02-16 | 1968-08-17 | 1969-02-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1972-02-16 | 1972-08-17 | 1973-02-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1976-02-16 | 1976-08-17 | 1977-02-16 | $7700.00 | Window Closed / Lapsed |