温度开关动作温度误差的测量及不确定度评定

Measurement and Uncertainty Evaluation of Temperature Error of Temperature Switch

温度开关是工业控制系统中的重要部件,其准确性直接影响设备的性能。动作温度误差是温度开关的重要计量特性。为保证量值的准确,本文采用精密数字温度计和具备可调升降温速率功能的标准恒温油槽,组成温度开关校准系统,对动作温度误差进行校准,并对测得值的扩展不确定度进行分析评定。实验证明:校准双金属温度开关时,动作温度误差的扩展不确定度为U=0.5℃(k=2),满足温度开关校准的要求,具有应用价值。

Temperature switch is an important part of industrial control system,and its accuracy directly affects the performance of equipment.Operating temperature error is an important measurement characteristic of temperature switch.In order to ensure the accuracy of the measured values,a precision digital thermometer and a standard con-stant temperature oil tank with adjustable rising and cooling rate are used to form a temperature switch calibration system to calibrate the operating temperature error and evaluate the extended uncertainty of the measured val-ues.Experimental results show that the extended uncertainty of operating temperature error is U=0.5℃(k=2)when calibrating bimetallic temperature switch,which meets the requirements of temperature switch calibration and has application value.