Flame sensing system
First Claim
1. A flame sensing apparatus comprising a warning device for indicating the existence of a flame, detecting means for detecting a difference in intensity between a first radiation of wavelengths produced by resonant radiation of carbon dioxide and a second radiation of wavelengths which are in the vicinity of the wavelengths of the first radiation and in which there is little absorption by the carbon dioxide in the air, a level detector for producing a warning device actuating signal when the intensity of the second radiation exceeds a predetermined level, gating means for controlling passage of said warning device actuating signal from said level detector to said warning device, and gate controlling means for opening said gating means for a predetermined time when said difference detected by said detecting means exceeds a predetermined value, thereby permitting said warning device actuating signal to pass through said gating means to be applied to said warning device so that the warning device may provide an indication of the existence of a flame.
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Abstract
The present invention is concerned with a flame sensing system utilizing infra-red rays by resonant radiation of carbon dioxide which system gives no erroneous information due to discharge of thunder, solar light or the like and has high sensitivity and S/N ratio. The flame sensing system according to the invention is characterized in that a flame is detected continuously for a short time in terms of difference in intensity between a first infra-red rays of a first wavelength produced by resonant radiation of carbon dioxide and a second infra-red rays of a wavelength located in the vicinity of said first wavelength in the region of wavelength in which there is little absorption by carbon dioxide in the air and then a warning device is actuated while the intensity of said second infra-red rays remains beyond a predetermined level.
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Citations
3 Claims
- 1. A flame sensing apparatus comprising a warning device for indicating the existence of a flame, detecting means for detecting a difference in intensity between a first radiation of wavelengths produced by resonant radiation of carbon dioxide and a second radiation of wavelengths which are in the vicinity of the wavelengths of the first radiation and in which there is little absorption by the carbon dioxide in the air, a level detector for producing a warning device actuating signal when the intensity of the second radiation exceeds a predetermined level, gating means for controlling passage of said warning device actuating signal from said level detector to said warning device, and gate controlling means for opening said gating means for a predetermined time when said difference detected by said detecting means exceeds a predetermined value, thereby permitting said warning device actuating signal to pass through said gating means to be applied to said warning device so that the warning device may provide an indication of the existence of a flame.
Specification