Calibration interval of standard platinum resistance thermometers in a range between 0 °C and 419 °C

摘要

The calibration interval of standard platinum resistance thermometers (SPRTs) was studied using the fixed-point calibration data accumulated for eleven years. A model was proposed to predict the long-term drift of the change rate of resistance R_(TPW) at the triple point water and the resistance ratio at the freezing point of Sn (W_(Sn)) and Zn (W_(Zn)). A Monte Carlo simulation was carried out to present the calibration interval in terms of the measurement reliability of SPRT over elapsed times after a calibration based on the model with various target tolerance limit of the drifts.