精密露点仪的露点与相对湿度换算及验证研究  

Study on dew point and relative humidity conversion and verification of precision dew point hygrometer

作　　者：张文东[1] 崔体运[1] 沈淘淘[1] 张勇[1] ZHANG Wendong;CUI Tiyun;SHEN Taotao;ZHANG Yong(Shanghai Institute of Measurement and Testing Technology,Shanghai 201203,China)

机构地区：[1]上海市计量测试技术研究院,上海201203

出　　处：《计测技术》2022年第2期97-101,共5页Metrology & Measurement Technology

摘　　要：为验证精密露点仪内置相对湿度换算结果的准确性,将国际上普遍认可的Sonntag饱和水蒸气压公式和Hardy湿空气增值系数公式应用于露点与相对湿度换算公式中,作为标准换算方法对多款常用精密露点仪的内置相对湿度换算结果进行了验证,结果表明0.01℃分辨力的仪器相对湿度显示值与计算值的偏差均不超过±0.03%RH;个别0.1℃分辨力仪器的相对湿度偏差则达到±0.5%RH。可见,0.1℃分辨力的仪器难以满足作为相对湿度标准器的要求。对于无露霜点判别功能的仪器,结果显示按露点与按霜点换算得到的相对湿度差异很大,且与实际相对湿度差异也很大,因此不能用于负露点条件下相对湿度的测量。由该公式还得到以下结论:增值系数在常温常压下对露点与相对湿度换算结果影响很小,可忽略,在高温低压时则有一定影响,不可忽略。In order to verify the accuracy of the built-in relative-humidity conversion results of the precision dew point hygrometer,the internationally recognized Sonntag's saturated water vapor pressure formula and Hardy's wet air enhancement factor formula were applied to the dew point and relative humidity conversion formula,which was used as a standard conversion method to verify the builtin relative humidity conversion results of a variety of commonly used precision dew point hygrometers.The results show that the deviation between the displayed value and the calculated value of relative humidity is no more than±0.03%RH for the instrument with resolution of 0.01℃,and the relative humidity deviation of individual instruments with resolution of 0.1℃reaches±0.5%RH.So it is difficult for an instrument with resolution of 0.1℃to meet the requirements of a relative humidity standard.For the instrument without dew and frost point discrimination function,the results show that the relative humidity obtained by dew point and frost point conversion is very different,and it is also very different from the actual relative humidity,so it cannot be used for the measurement of relative humidity at negative dew point.The formula also results in the following conclusions:the enhancement factor has little effect on the results of the dew point and relative humidity conversion under normal temperature and pressure,which is negligible,but has a certain effect at high temperature and low pressure,which cannot be ignored.

关 键 词：增值系数 饱和水蒸气压公式 露点与相对湿度换算公式 精密露点仪 

分 类 号：TB943[一般工业技术—计量学]