| 摘要 |
There is describes a filter arrangement (10) for a particle detector (12) for detecting particles in an environment. The particle detector (12) can include one or more sensors (30) for analysing fluid in a detection region to produce sensor output. The filter arrangement (30) includes structure defining flow paths, for conveying fluid from the environment towards the detection region, including a first flow path (22), which includes a filter(26), and a second flow path (24) bypassing the filter(10). There is also provided a mechanism (120B) for controlling relative flow rates of fluid through the first flow path (22) and the second flow path (24) and a controller (32) configured to receive the sensor output corresponding to at least two relative flow rates and apply logic thereto to generate an output indicative of a condition of the filter. |
