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Early fire detection using temperature and smoke sensing

  • US 6,195,011 B1
  • Filed: 10/02/1998
  • Issued: 02/27/2001
  • Est. Priority Date: 07/02/1996
  • Status: Expired due to Term
First Claim
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1. A fire alarm system comprising:

  • a smoke sensing unit which detects a smoke associated with fire;

    a temperature sensing unit which detects temperature changes associated with fire; and

    a controller which compares a quantity of detected smoke to a smoke threshold, the temperature level to a temperature threshold, a rate of rise of the temperature level to a rate threshold, and determines combined changes in the quantity of detected smoke and the temperature changes over time, and which sets an alarm condition based upon any one of

         1) the quantity of detected smoke passing the smoke threshold,

         2) the temperature level passing the temperature threshold,

         3) the rate of rise of the temperature level exceeding the rate threshold, or

         4) when the changes in the quantity of detected smoke over time coupled with the temperature changes over time are indicative of a fire.

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