• US 3,805,066 A
  • Filed: 08/14/1972
  • Issued: 04/16/1974
  • Est. Priority Date: 08/14/1972
  • Status: Expired due to Term
First Claim
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1. A smoke detecting device, comprising:

  • a plurality of optical fibers including a first optical fiber having a free end and a coupled end, a last optical fiber having a free end and a coupled end and intermediate optical fibers having two coupled ends in serial alignment and each pair of consecutively aligned optical fibers defining a gap between the adjacent coupled ends thereof;

    a light source and focusing means positioned opposite the free end of the first of the serially aligned optical fibers for introducing light rays into the first optical fiber for transfer through the serially arranged optic fibers;

    a coupling means operatively positioned between each of the adjacent optical fibers and firmly retaining the ends thereof in proper alignment and maintaining the gap therebetween, the coupling means defining a plurality of apertures appropriately positioned to allow smoke to enter therein and to pass through the gap between the adjacent ends of coupled optical fibers, diminishing the amount of light transferred from one optical fiber to the adjacent optical fiber in direct relation to the amount of smoke in the gap;

    a photoelectric transducer means operatively positioned for receiving light transmitted through the serially arranged optical fibers and delivered from the unconnected end of the last optical fiber to convert the light received into an electrical voltage; and

    a discriminator circuit operatively connected to the photoelectric transducer means for producing a pre-determined electric signal for indicating the detection of smoke whenever the variation of the electrical voltage caused by the diminution of received light due to the presence of smoke in the gaps exceeds a preset value.

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