影响热导传感器气体检测性能的原因分析

Analysis of Reasons Affecting Gas Detection Performance of thermal Conductivity Sensor

热导气体传感器具有检测范围大,可检测多种气体,检测装置简单、成本低廉等许多优点,但也存在检测精度差、灵敏度低等缺陷,限制了该传感器的广泛应用。文中介绍了热导传感器气体检测的基本原理和传统的检测方法,根据传热学理论建立了热导传感器的热平衡方程,在此基础上对传统气体检测方法进行了分析和研究,得出了传感器温度随被测气体浓度的变化而变化的特性是影响气体检测性能的根本原因的结论,并指出采用恒温检测方法是一个有效的解决办法。

Thermal conductivity sensor (TCS) has many advantages, such as versatility, simplicity, stability, and low cost. But TCS also has disadvantages as relative low sensitivity and high detection error, which makes TCS rarely used for gas detection. In this paper the principle of gas detection using TCS and traditional detecting method for gas detection are presented, heat equilibrium equation of TCS is established based on theory of heat transfer and reasons affecting gas detection performance of TCS are analyzed. Finally it is pointed out that the variation of temperature of TCS with gas concentration is the influential reason affecting gas detection performance and applying constant temperature detection method is an effectual solution.