US Patent 9269248 Environmental parameter responsive, aspirated fire detector

An aspirated smoke detector includes at least one ambient atmosphere inflow collection pipe with a plurality of inflow ports arranged along the pipe. The ports of the pipe are defined at least in part by temperature sensitive materials which alter the area of the respective inflow port in response to physical and/or chemical changes. As the temperature increases the area increases, thereby drawing more of the local ambient air and airborne particulate matter into the flow pipe, and then onto the smoke sensing chamber. This increased flow off-sets the dilution present due to other air in the respective pipe from other inflow ports which might not be near the developing fire condition.