| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a fire alarm device capable of preventing the misjudgement of fire occurrence even when temperature is suddenly raised due to a cause other than a fire by discriminating the occurrence of a fire at the time of continuously obtaining the prescribed number of measuring points satisfying a prescribed condition on an optical fiber cable. SOLUTION: The fire alarm device FA1 is provided with an optical fiber cable 10, a terminal box 20, a repeater 30, a fire receiver RF, and a fire display device 40. The repeater 30 makes laser beam incident upon the cable 10, receives scattered light in the cable 10 and calculates temperature on a scattered light generation position to judge a fire. Since the occurrence of a fire is discriminated at the time of detecting prescribed temperature rise on the prescribed number of measuring points, area fire occurrence can be discriminated. Even when temperature is suddenly raised on a specific position due to a cause other than a fire, it is not misjudged as a fire.</p> |
