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Function test means of photoelectric type smoke detector

  • US 4,647,785 A
  • Filed: 03/26/1984
  • Issued: 03/03/1987
  • Est. Priority Date: 04/08/1983
  • Status: Expired due to Fees
First Claim
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1. A function testing means for a photoelectric smoke detector, comprising:

  • a first light-emitting element for smoke detection;

    a first light-receiving element for smoke detection by reception of light scattered from smoke arranged at a location shielded from direct irradiation by said first light emitting element and having an output;

    a second light-receiving element for monitoring radiation emitted by said first light-emitting element and having an output;

    a second light-emitting element for emitting radiation in proportion to said output of said second light-receiving element toward said first light-receiving element;

    function testing means for operating the photoelectric smoke detector in a test mode in which said first light-emitting element and said second light-emitting element simultaneously emit radiation;

    operational means for operating the photoelectric smoke detector in a detection mode in which only said first light-emitting element emits radiation;

    switching means for alternatively performing said test mode and said detection mode; and

    monitor means for continuously monitoring said output of said first light-receiving element in each of said test mode and said detection mode.

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