US3614280A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ignition and flame detection system utilizing a single electrode
Assignee: Tokyo Gas Co Ltd
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Filing: 1969-12-22
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Granted: 1971-10-19
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Expires: 1989-12-22
Abstract
Abstract A single electrode is positioned adjacent a burner in a furnace. A single circuit supplies current to create an arc across the electrode to the burner to ignite the furnace. The same circuit detects a DC current from the electrode to the burner due to the electric conductivity of the flame. The circuit includes means to shunt any AC current from the detector. An insulation material covers the electrode adjacent the arc-creating end to stabilize the DC current.
Inventors
- 👤 Tamio Yamaguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:51
CPC Classifications
F; F23; F23Q; F23Q3/00; F23N; F23N5/00; F23N5/02; F23N5/12; F23N5/123; F23Q1/00; F23Q1/02; F23Q1/06; F23N2227/00; F23N2227/36; F23N5/20
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
168 words
A furnace ignition and flame detection system comprising a burner mounted in the wall of the furnace; means for supplying fuel to said burner; an electrode positioned adjacent said burner; transformer means connected in series with said electrode for supplying AC current at a high voltage to said electrode to create an arc between said electrode and said burner and thus ignite said fuel, said transformer means adapted to reduce said voltage to a level below that sufficient to create said arc after the ignition of said fuel; said electrode and said burner adapted to have a pulsating DC current flow therebetween due to the electric conductivity of said flame only when said fuel is ignited; a transistorized flame detection means conNected in series with said burner and said transformer means for detecting the absence of said pulsating DC current when said flame is not present; and bypass circuit means connected in parallel with said detection means for preventing said AC current from flowing to said detection means.
Claim 2
Dependent Claim
168 words
A furnace ignition and flame detection system comprising a burner mounted in the wall of the furnace; means for supplying fuel to said burner; an electrode positioned adjacent said burner; transformer means connected in series with said electrode for supplying AC current at a high voltage to said electrode to create an arc between said electrode and said burner and thus ignite said fuel, said transformer means adapted to reduce said voltage to a level below that sufficient to create said arc after the ignition of said fuel; said electrode and said burner adapted to have a pulsating DC current flow therebetween due to the electric conductivity of said flame only when said fuel is ignited; a transistorized flame detection means conNected in series with said burner and said transformer means for detecting the absence of said pulsating DC current when said flame is not present; and bypass circuit means connected in parallel with said detection means for preventing said AC current from flowing to said detection means.
Claim 3
Dependent Claim
43 words
A system as claimed in claim 1, wherein said transistorized flame detection means comprises a plurality of transistors, and said bypass circuit means comprises a varistor and a plurality of capacitors connected in parallel and a resistor connected in series with said capacitors.
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) | 1974-10-18 | 1975-04-19 | 1975-10-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-18 | 1979-04-19 | 1979-10-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-18 | 1983-04-19 | 1983-10-19 | $7700.00 | Window Closed / Lapsed |