一种高精度薄膜铂电阻温度计测量迟滞性的研究

为了研究热迟滞性对工业铂电阻温度计测量不确定度的影响,选取了8支高精度铂电阻温度计进行实验。在-50～150℃内,选择3个温度区间,采用两种标准方法(IEC 60751,ASTM E644)测量水三相点(0.01℃)和所选温度范围内的中间点的迟滞性变化。实验结果表明:4支薄膜铂电阻温度计在两种标准方法测量下,随着温度区间跨度增大,热迟滞性影响增大,IEC 60751标准方法测量的热迟滞性最大值为14.2mK,ASTM E644标准方法测量的热迟滞性最大值为20.5mK;选取4支铂丝铂电阻温度计在温度范围为-50～150℃测量时,IEC 60751和ASTM E644标准方法测量的热迟滞性数据最大值分别为1.1mK和0.9mK;铂丝铂电阻温度计热迟滞性明显小于薄膜铂电阻温度计。

Research on Hysteresis of the High-precision Thin-film Platinum Tesistance Thermometers

Hysteresis is one of the sources of the measurement uncertainty of industrial platinum resistance thermometers(IPRTs). Eight high-precision platinum resistance thermometers(PRTs) were selected to study the influence of the measurement uncertainty due to the hysteresis. The temperature range was between -50℃ and 150℃, and three temperature span thermal hysteresis experiments were carried out. Two standard methods were used to get the thermal hysteresis values which were the change of resistance at the triple point of water and at the midpoint in the temperature range. The experimental results showed that the influence of thermal hysteresis of four thin-film PRTs increases with the increase of temperature range span under the two standard methods, the largest thermal hysteresis measured by IEC 60751 standard method was 14.2mK, and the maximum thermal hysteresis measured by ASTM E644 standard was 20.5mK. The maximum thermal hysteresis measured by the IEC 60751 standard method and the ASTM E644 standard method was 1.1mK and 0.9mK, respectively, when the four platinum wire PRTs were measured at a temperature range of -50℃ to 150℃. The platinum wire PRTs has significantly lower thermal hysteresis than the thin-film PRTs.