Patent US4755133A successfully refreshed from Google Patents.
US4755133A
Expired / Lapsed
US
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Primary gas furnace control
Assignee: Robertshaw Controls Co
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Filing: 1987-04-13
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Granted: 1988-07-05
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Expires: 2007-04-13
Abstract
Abstract A primary gas furnace control including a thermostatically controlled intermittent ignition system, the control being effective to monitor and control main gas valve action through use of flame rectification. The control features a slight delay on main valve dropout with flame failure and an extension of the ignition source into the main burner cycle to prevent nuisance recycling. If desired, the control may also include timed pilot valve, thermostat resettable, lockout as well as prepurge capability for use in applications requiring a furnace combustion chamber purge prior to an ignition cycle.
Inventors
- 👤 Frederick J. Geary
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 06:06
CPC Classifications
F; F23; F23Q; F23Q9/00; F23Q9/08; F23Q9/12; F23Q9/14; F23N; F23N5/00; F23N5/20; F23N5/203; F23Q3/00; F23Q3/004
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
198 words
In a primary control for gas furnaces, the combination including a low voltage circuit adapted to be connected to a source of low voltage AC current, said low voltage circuit including a thermostatic switch, an electricallyoperable pilot gs valve, an electricallyoperable main gas valve, pulse generating means for controlling energization of said main gas valve, and first relay means controlling the energization of said main gas valve and said pulse generating means, a high voltage spark generating circuit including spaced electrodes disposed in the path of gas emanating form said pilot valve, means interfacing said low voltage circuit and said spark generating circuit and providing a substantially higher voltage in said spark generating circuit than in said low voltage circuit, and flame sensing means including a probe disposed in the path of gas emanating from said pilot gas valve and being subjected to the heat of the gas flame when gas ignition is obtained by said spark generating circuit whereby flame rectification s effected, said flame sensing means controlling said main gas valve and said pulse generating means through said first relay means, said low voltage circuit including second relay means controlling the energizatin of said pilot valve.
Claim 2
Dependent Claim
198 words
In a primary control for gas furnaces, the combination including a low voltage circuit adapted to be connected to a source of low voltage AC current, said low voltage circuit including a thermostatic switch, an electricallyoperable pilot gs valve, an electricallyoperable main gas valve, pulse generating means for controlling energization of said main gas valve, and first relay means controlling the energization of said main gas valve and said pulse generating means, a high voltage spark generating circuit including spaced electrodes disposed in the path of gas emanating form said pilot valve, means interfacing said low voltage circuit and said spark generating circuit and providing a substantially higher voltage in said spark generating circuit than in said low voltage circuit, and flame sensing means including a probe disposed in the path of gas emanating from said pilot gas valve and being subjected to the heat of the gas flame when gas ignition is obtained by said spark generating circuit whereby flame rectification s effected, said flame sensing means controlling said main gas valve and said pulse generating means through said first relay means, said low voltage circuit including second relay means controlling the energizatin of said pilot valve.
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) | 1991-07-05 | 1992-01-04 | 1992-07-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-07-05 | 1996-01-04 | 1996-07-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-07-05 | 2000-01-04 | 2000-07-05 | $7700.00 | Window Closed / Lapsed |