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FIRE DETECTOR UTILIZING ULTRAVIOLET AND INFRARED SENSORS

  • US 3,665,440 A
  • Filed: 08/19/1969
  • Issued: 05/23/1972
  • Est. Priority Date: 08/19/1969
  • Status: Expired due to Term
First Claim
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1. A fire detector comprising a first radiation detection means for providing a first signal in a first channel as a function of radiation detected substantially in the infrared region of the spectrum, first filter means in said first channel for passing said first signal within a predetermined flicker frequency range, said flicker frequency range being about 5 to 20 cycles per second, threshold means in said first channel for providing an output signal as a result of a signal of a predetermined amplitude at the output of said first filter means, second radiation detection means in a second channel for providing a second signal as a function of radiation detected substantially in the ultraviolet region of the spectrum, second filter means in said second channel for passing said second signal within said predetermined flicker frequency range, gating means normally inhibited by the presence of said second signal in said second channel, means for applying said first signal in said first channel to said gating means, integrating means responsive to said first signal of a predetermined duration of at least 5 seconds appearing at the output of said gating means, and alarm means actuated by said integrating means.

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