| 摘要 |
A fire detection system comprises an expansion member 2 associated with a sensor mechanism 3. The sensor mechanism 3 is coupled to an alert module 4. The expansion member 2 is arranged to expand by a first predetermined amount when exposed to a first temperature, and to expand by a second predetermined amount when exposed to a second temperature. The first temperature is lower than the second temperature and the first expansion (from a normal condition such a room temperature) is less than the second predetermined expansion (from the normal condition). The sensor mechanism 3 is configured to detect the expansion of the expansion member 2 and to issue a first signal on sensing the first predetermined expansion and a second signal on sensing a second predetermined expansion. The first and second signals are received by the alert module 4 which in turn is configured to transmit an alert signal once the alert module 4 has received both the first and second signals. The expansion member may be a linear elongate expansion member configured to increase in length when heated. |
