Fire detecting apparatus

A photoelectric type fire detecting apparatus comprising:

• detection means for repeatedly detecting a physical quantity of smoke and successively outputting corresponding detection outputs according to a predetermined number of detecting operations;
• storage means for successively storing a predetermined number of most recent detection outputs from said detection means;
• deviation calculation means for obtaining all combinations of any two of said predetermined number of detection outputs stored in said storage means and for calculating either a deviation value or a ratio between said two detection outputs in each of said combinations;
• determination means for determining which of said combinations of two detection outputs obtained by said deviation calculation means have either the smallest deviations or smallest ratios therebetween;
• calculation means for calculating a detection value based on said combinations of two detection outputs determined by said determination means;
• and
• sending means for sending the detection value calculated by said calculation means as information denoting the physical quantity of the smoke.

A thermal type fire detecting apparatus comprising:

• detection means for repeatedly detecting a physical quantity of heat and successively outputting corresponding detection outputs according to a predetermined number of detecting operations;
• storage means for successively storing a predetermined number of most recent detection outputs from said detection means;
• deviation calculation means for obtaining all combinations of any two of said predetermined number of detection outputs stored in said storage means and for calculating either a deviation value or a ratio between said two detection outputs in each combination;
• determination means for determining which of the two detection outputs obtained by said deviation calculation means have either the smallest deviations or smallest ratios therebetween;
• calculation means for calculating a detection value on the basis of the two detection outputs determined by said determination means;
• and
• sending means for sending the detection value calculated by said calculation means as information denoting the physical quantity of the heat.