US3569783A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ac fed switching means for the flame monitors of heating systems
Assignee: Danfoss AS
•
Filing: 1969-07-16
•
Granted: 1971-03-09
•
Expires: 1989-07-16
Abstract
Abstract The invention relates to AC fed switching means for the flame monitor of a heating system. A DC motor relay is connected in series with the heating coil of a safety switch and with a photoelectrically operated swotch. The photoelectrically operated switch is bridged by a resistor and the motor relay is bridged by a rectifier.
Inventors
- 👤 Holger Nicolaisen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 21:13
CPC Classifications
F; F23; F23N; F23N5/00; F23N5/20; F23N5/203; F23N5/02; F23N5/08; F23N5/082
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
57 words
A flame monitoring circuit for a heating system comprising an AC source, a DC motor relay, a heating coil of a safety switch in series with said motor relay, a photoelectrically operated switch in series with said motor relay, said photoelectrically operated switch being bridged by a resistor, and said motor relay being bridged by a rectifier.
Claim 2
Dependent Claim
57 words
A flame monitoring circuit for a heating system comprising an AC source, a DC motor relay, a heating coil of a safety switch in series with said motor relay, a photoelectrically operated switch in series with said motor relay, said photoelectrically operated switch being bridged by a resistor, and said motor relay being bridged by a rectifier.
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) | 1974-03-08 | 1974-09-07 | 1975-03-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-08 | 1978-09-07 | 1979-03-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-08 | 1982-09-07 | 1983-03-09 | $7700.00 | Window Closed / Lapsed |