氧氮分析仪的热导检测器及热敏元件选择

讨论了金属中氧氮分析仪所用热导检测器及其核心热敏元件的选择。基于NTC热敏电阻阻值大,所需桥流小,且元件采用惰气保护密闭封装,能够抵御恶劣的环境条件,很好地保持热导检测器测量电桥的对称性、稳定性,具有应用灵活、简单的特点,选择NTC热敏电阻作为热导检测器的热敏元件,并应用于金属中氧氮分析仪,其线性和灵敏度均符合仪器使用和分析要求。采用NTC热敏电阻作为热敏元件、选择扩散型热导池结构研制的热导检测器应用于ON-2008氧氮分析仪中。分别采用高含量和低含量氮的标准物质对仪器的高氮和低氮两个测量通道的线性和精密

The choice of thermal conductivity detector and thermal elements applied in oxygen and nitrogen analyzer

The choice of the structure of thermal conductivity cell and the thermal elements used in thermal conductivity detector was discussed.Based on the high resistance value and low current requirement NTC thermistor is chosen as the thermal elements applied in oxygen and nitrogen analyzer.Due to being protected in the bubble filled with inert gas,the requirement for the carrier gas is not so high and the thermistor is hard to be oxidized.The symmetry,stability and flexibility of measuring electric bridge is more easier to achieve.The linearity and sensitivity of oxygen and nitrogen analyzer with NTC thermal conductivity detector can be fully meet the needs for the determination of oxygen and nitrogen.NTC thermistor and diffusion structure are used in ON-2008 oxygen and nitrogen analyzer.Various CRMs are used to check the linearity and precision of high and low content nitrogen channels on the analyzer.The results show that the linearity is good,the correlation coefficient is 0.999 9 and 0.999 3,RSD is <2% and <6%,respectively.Compared with similar analyzer,the results is identical.