| 摘要 |
The ionisation fire detector is used in the case of smoke detectors which are to have low radio activity. The detector comprises a measuring chamber (11) with radiation sources (14) and a reference resistance (Rv). Chamber and resistance are connected in series to a supply voltage (Uo). The measuring electrode (13) and the grid electrode (12) are held by insulating supports (16) and (15), respectively. The two supports are electrically connected independently of each other to the input electrode (1). The reference resistance (Rv) is chosen such that its value is at least half as small as the resistance value (RM) of the measuring chamber (11). By these measures, an ionisation fire detector which manages with low radiation activity is provided. <IMAGE>
|
