Nachweis von Schmutzstoffen in der Luft

摘要

A smoke detection system comprises a manifold (4) connected to a series of sampling pipes (2). A fan (6) which draws a large volume of sampling air through the sampling pipes is connected to the inlet manifold and a small proportion of that air is directed to the inlet of a smoke detector (12), the outlet of which is connected to the manifold. The configuration obtained by the connection of the outlet from the detector into the inlet manifold provides a large pressure drop across the flow path through the detector. As a result of the large pressure drop, a filter (10) for removing dust and other contaminants can be incorporated in the flow path and the filter can also incorporate a fine filtering stage to produce a secondary clear air flow which can be directed into the detector to prevent smoke particles from settling on critical components of the detector.