恒定低温法在低湿区露点检测中的应用

Application of constant low temperature in low humidity dew point measurement

在低湿区环境下的露点检测中,电容式露点传感器测量的频率与露点值呈现非线性,且受环境温度影响很大,此外,湿度越低,测量的分辨力也越低。采用了一种恒定低温方法来检测低湿区露点,即传感器的环境温度恒定保持在0℃以下,可大大提高低湿区的测量分辨力,再根据露点值与频率值间具有的确定的非线性关系,将采集的频率经牛顿插值计算后就可得到露点值。采用该方法大大提高了电容式露点仪在低湿区露点检测的分辨力,扩展了其测量范围。

The value for dew point vs frequency measured by the capacitance dew point sensor is nonlinear in measurement of low humidity dew point and is easily affected by the circumstance temperature.Furthermore,the lower humidity,the lower resolution.The method of constant low temperature is studied and adopted to measure the low humidity dew point.First keeping the sensor at constant low temperature of 0℃to improve the low humidity measuring resolution.Then based on the determinate nonlinear relation in capacitance vs dew point value,the Newton interpolation is used to deal with the frequency value and the corresponding dew point value is calculated.The method will improve the measuring resolution in low humidity and enlarge its measuring range to a great extent.