光声光谱火灾气体探测系统

气体是火灾中最早出现的燃烧产物,利用燃烧过程中产生的气体作为判据能在很大程度上提高火灾探测及预警的早期性。光声光谱技术由于其在气体检测领域的高灵敏度、宽检测范围等优点已成为火灾探测的一个重要的发展方向。介绍了光声光谱技术原理,设计了一套基于光声原理的火灾气体探测系统。对该系统的基本性能进行了测试,并对棉绳阴燃和聚氨酯泡沫明火实验中产生的气体浓度(CO)进行了测量,根据光声信号的变化并结合一定的算法反演得到了这两组实验中CO的浓度变化曲线。实验表明,该探测系统对火灾能够很好地响应,能够满足探测需求。

Fire gases detection system based on photoacoustic spectroscopy principle

Gases is the earliest combustion products in fire.Detecting the fire by using gases released during burning process can achieve fire detection and warning earlier.Photoacoustic spectroscopy technique has been an important development direction of fire detection due to its high sensitivity,wide detection range and other advantages.The photoacoustic spectroscopy principle was introduced,and a set of fire gases detection system based on photoacoustic spectroscopy principle was designed.A beam of infrared light with central wavelength of 1579nm was used as the light source of detection system.And wavelength modulation technology was employed to transform continuous light into time-varying light.A certain amount of carbon monoxide was sealed in photoacoustic cell,generating an initial photoacoustic signal even if in the absence of fire.When a fire occurs,carbon monoxide from fire products absorbs infrared light emitted from light source,resulting in photoacoustic signal decreased.According to variation of photoacoustic signal,the carbon monoxide gas concentration in the air could be calculated by a specific algorithm.The basic performance of the system was tested and the concentration of carbon monoxide released from cotton rope smoldering fire and polyurethane fire was measured.Thecarbon monoxide concentration curves of two sets of experiments mentioned above were obtained.The measurement results showed that the system reacts very well to fire,which can meet the demand for fire detection.