HEAT AND SMOKE COMPOSITE SENSOR, FIRE ALARM AND FIRE ALARM SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a heat and smoke composite sensor, a fire alarm and a fire alarm system which can find a fire more rapidly. SOLUTION: The heat and smoke composite sensor comprises a heat sensing means 11 which acquires temperature changeΔT; a smoke sensing means 12 which acquires smoke density S; a heat level comparison means 14 which bears a prediction heat level LT2 and outputs a high heat sensing signal when the temperature changeΔT is larger than the prediction heat level LT2; a smoke level comparison means 15 which bears a prediction smoke level LS2 and outputs a smoke sensing signal when the smoke density S varies from a value higher than the prediction smoke level LS2 to a value lower than the level; and a fire determination means 16 which determines that a fire has broken out when the high heat sensing signal is received from the heat level comparison means 14, from a time point when the smoke sensing signal is received from the smoke level comparison means 15 untill the time before elapsing a prediction determination time limit TM. COPYRIGHT: (C)2004,JPO&NCIPI