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US 4,381,455 AGranted
Flame detector including detector testing apparatus
AssigneeTokyo Shibaura Denki Kabushiki Kaisha
InventorToshiyuki Komori
Life of this patent
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Abstract
A flame detector for monitoring the flame of a burner including an electrically actuatable photo shielding element positioned between a photoelectric element and the flame. The normally transparent photo shielding element may be turned opaque on command for simulating a no flame condition of the burner. The resulting signal from the photoelectric element is compared with a predetermined signal level, when there is actually no flame, for testing the flame detector.
Claims8
A flame detector comprising:
- a photoelectric element for detecting a light from a flame and producing a current;
- a photo shielding element for shielding the light of the flame from the photoelectric element when the photo shielding element is opaque and for permitting said photoelectric element to detect the light of the flame when said photo shielding element is transparent, said photo shielding element being electrically actuated to be opaque or transparent;
- means for converting said current of said photoelectric element to a constant-current;
- a load for varying the terminal voltage thereof according to said constant-current, said load being applied to a power source through said constant-current;
- a testing signal circuit constituting a filter circuit for said power source;
- a switch for connecting said testing signal circuit to said power source, said switch being open to output a voltage containing a testing signal from said power source;
- a circuit for separating the testing signal from the output voltage of said power source when said testing signal circuit is separated while said switch is open;
- and a driver circuit for actuating said photo shielding element to be opaque according to said testing signal.
5 more elements
Dependencies are inferred from the claim text.