火灾探测领域的新方法探讨——光声气体火灾探测器

New method of fire detection-Photo acoustics gas fire detector

光声气体火灾探测器是基于红外光声原理测量CO_2等气体浓度的探测器。由于吸收和散射的作用,大气中的许多分子和粒子使得红外光束消失。吸收发生在每个分子特定的波长。气体通过扩散膜进入一个小室,气体在对CO_2特定的吸收波长被脉冲红外灯照射,气体分子对辐射能的吸收引起测量室压力的微小变化可以用麦克风探测出来。放大并且线性化后的信号与气体浓度成比例。

A detector for measuring the gas concentration of carbon dioxide is based on an infrared photo acoustic principle. Many molecules and particles in the atmosphere cause extinction of an incident beam of infrared radia- tion due to absorption and scattering processes. The absorption occurs at wavelengths that are very specific for each molecule. The ambient gas enters a small cell via a diffusion membrane. The gas is irradiated with pulsed infrared light at the specific absorption wavelength for carbon dioxide. The absorption of the radiation energy by the gas molecules causes slight variations of the pressure inside the measuring cell that can be detected with a mi- crophone. The amplified and subsequently 1inearized microphone signal is proportional to the presented gas con- centration.