Patent US2354211A successfully refreshed from Google Patents.
US3147465A
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Methane alarm and control system
Assignee: MSA Safety Inc
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Filing: 1960-12-27
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Granted: 1964-09-01
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Expires: 1980-12-27
Abstract
No abstract record available.
Inventors
- 👤 Brown Harry Shaffer
- 👤 Green Daniel Andrew
- 👤 Ross Edward Joseph
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 01:18
CPC Classifications
G; G08; G08B; G08B17/00; G08B17/10; G08B17/117; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/14; G01N27/16; G08B21/00; G08B21/02; G08B21/12; G08B21/16
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
142 words
A METHANE ALARM AND CONTROL SYSTEM IN COMBINATION, COMPRISING: A BLOCKING OSCILLATOR CIRCUIT WHICH RECEIVES DIRECT CURRENT AND CHANGES IT INTO PULSATING CURRENT; A HOT-WIRE ELECTRICAL BRIDGE CIRCUIT INCLUDING A DETECTOR FILAMENT SENSITIVE TO THE PRESENCE OF A NOXIOUS GAS; CIRCUIT MEANS COUPLING SAID BLOCKING OSCILLATOR TO SAID BRIDGE CIRCUIT; A FLIP-FLOP NETWORK HAVING AN INPUT AND AN OUTPUT, THE INPUT BEING COUPLED TO SAID BRIDGE CIRCUIT TO RECEIVE CURRENT PULSES; RELAY MEANS RESPONSIVE TO THE OUTPUT OF SAID FLIP-FLOP NETWORK FOR CONTROLLING AN ALARM CIRCUIT; SAID DETECTOR FILAMENT BEING AT TIMES SUBJECTED TO A FRESH AIR CONDITION, AND OPERATIVE TO CAUSE SAID PULSATING CURRENT TO BE OF SUFFICIENT STRENGTH TO MAINTAIN SAID RELAY MEANS ENERGIZED, SAID DETECTOR FILAMENT AT OTHER TIMES BEING SUBJECTED TO NOXIOUS GAS TO CAUSE REDUCED STRENGTH OF THE PULSATING CURRENT CAUSING SAID RELAY MEANS TO BE DEENERGIZED.
Claim 2
Dependent Claim
142 words
A METHANE ALARM AND CONTROL SYSTEM IN COMBINATION, COMPRISING: A BLOCKING OSCILLATOR CIRCUIT WHICH RECEIVES DIRECT CURRENT AND CHANGES IT INTO PULSATING CURRENT; A HOT-WIRE ELECTRICAL BRIDGE CIRCUIT INCLUDING A DETECTOR FILAMENT SENSITIVE TO THE PRESENCE OF A NOXIOUS GAS; CIRCUIT MEANS COUPLING SAID BLOCKING OSCILLATOR TO SAID BRIDGE CIRCUIT; A FLIP-FLOP NETWORK HAVING AN INPUT AND AN OUTPUT, THE INPUT BEING COUPLED TO SAID BRIDGE CIRCUIT TO RECEIVE CURRENT PULSES; RELAY MEANS RESPONSIVE TO THE OUTPUT OF SAID FLIP-FLOP NETWORK FOR CONTROLLING AN ALARM CIRCUIT; SAID DETECTOR FILAMENT BEING AT TIMES SUBJECTED TO A FRESH AIR CONDITION, AND OPERATIVE TO CAUSE SAID PULSATING CURRENT TO BE OF SUFFICIENT STRENGTH TO MAINTAIN SAID RELAY MEANS ENERGIZED, SAID DETECTOR FILAMENT AT OTHER TIMES BEING SUBJECTED TO NOXIOUS GAS TO CAUSE REDUCED STRENGTH OF THE PULSATING CURRENT CAUSING SAID RELAY MEANS TO BE DEENERGIZED.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1967-09-01 | 1968-03-02 | 1968-09-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1971-09-01 | 1972-03-02 | 1972-09-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1975-09-01 | 1976-03-02 | 1976-09-01 | $7700.00 | Window Closed / Lapsed |