US3577209A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric ignition system
Assignee: Robertshaw Controls Co
•
Filing: 1969-02-28
•
Granted: 1971-05-04
•
Expires: 1989-02-28
Abstract
Abstract An electric ignition system utilizing an electric ignitor having a positive temperature coefficient of resistance and a negative temperature coefficient resistor coupled in series therewith to provide a constant resistance series network.
Inventors
- 👤 Charles H Perkins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 22:37
CPC Classifications
F; F23; F23Q; F23Q1/00; F23Q1/02; F23Q1/06
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
100 words
An electric ignition system for burner apparatus comprising: an electric ignitor having resistance varying with temperature in a predetermined relation, a power source connected to said ignitor for energizing the same, a resistor having a resistance varying with temperature in inverse relation to said predetermined relation, coupled in series with said ignitor and said source, means connecting said resistor in series with said ignitor and said source whereby current through said ignitor is maintained substantially constant with respect to temperature, and said ignitor having a positive temperature coefficient of resistance and said resistor having a negative temperature coefficient of resistance.
Claim 2
Dependent Claim
100 words
An electric ignition system for burner apparatus comprising: an electric ignitor having resistance varying with temperature in a predetermined relation, a power source connected to said ignitor for energizing the same, a resistor having a resistance varying with temperature in inverse relation to said predetermined relation, coupled in series with said ignitor and said source, means connecting said resistor in series with said ignitor and said source whereby current through said ignitor is maintained substantially constant with respect to temperature, and said ignitor having a positive temperature coefficient of resistance and said resistor having a negative temperature coefficient of resistance.
Claim 3
Dependent Claim
27 words
The electric ignition system for burner apparatus as recited in claim 1 wherein said ignitor is made of molybdenum disilicide and said resistor is a boron thermistor.
Claim 4
Dependent Claim
83 words
In a current regulating electric ignition system, the combination comprising: a source of electricity, an electric ignitor having a positive temperature coefficient of resistance and presenting a low resistance at low temperatures and a high resistance at igniting temperatures, a resistor connected in series with said electric ignitor and said source, said resistor having a negative temperature coefficient of resistance whereby current inrush through said electric ignitor when said electric ignitor presents said low resistance is prevented by the resistance of said resistor.
Claim 5
Dependent Claim
83 words
In a current regulating electric ignition system, the combination comprising: a source of electricity, an electric ignitor having a positive temperature coefficient of resistance and presenting a low resistance at low temperatures and a high resistance at igniting temperatures, a resistor connected in series with said electric ignitor and said source, said resistor having a negative temperature coefficient of resistance whereby current inrush through said electric ignitor when said electric ignitor presents said low resistance is prevented by the resistance of said resistor.
Claim 6
Dependent Claim
28 words
The current regulating electric ignition system a recited in claim 3 wherein said electric ignitor includes a molybdenum disilicide heating element and said resistor is a boron thermistor.
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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) | 1974-05-03 | 1974-11-02 | 1975-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-03 | 1978-11-02 | 1979-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-03 | 1982-11-02 | 1983-05-04 | $7700.00 | Window Closed / Lapsed |