Research of the Response Rate Variation for the Extinguishant Detection Technique Based on the Differential Pressure Principle

The intent of this work is to explore the variation mechanism of the response rate for the extinguishant detection technique based on the differential pressure principle, which is an aspirating concentration detection technique and quite suitable for extinguishant detection. The effects of the sampling pipe, sensing structure, and operating temperature on the response rate were analyzed, and the theoretical model was established by analyzing the gas dispersion behavior. It is found that the response/recovery time is greatly affected by the above factors, which can change from 0.068/0.088 to 0.960/1.01 s. Results show that with the increase of the length and inner diameter of the sampling pipe, the response/recovery time rapidly increases. For the sensing structure, the increase of the external diameter of the vascular bundles will increase the response/recovery time, and the increase of the throat diameter of the critical flow nozzle will greatly decrease the response/recovery time. The increase of the operating temperature can decrease the response/recovery time with limited improving effect. The research results in this article can provide suggestions for the design of sensor.