| 摘要 |
The device (30) has a sensor (305) for emitting a signal that represents presence of suspended particles in an ambient air. A fire detection circuit (310) processes the signal of the sensor to emit an alarm signal when a predetermined quantity of particles is represented by the signal of the sensor. An external surface (315) is formed on a path of air (325) towards the sensor. A part of the surface is made of an absorbent material or a hydrophobic material, where contact angles of the materials with water drops are lesser than 60 degrees and higher than 90 degrees, respectively. |
