engleski

Evaluation of calibration bath with two precision thermometers

The objective of this paper is to describe a specific procedure for evaluation of calibration baths used at Laboratory for Process Measurement (LPM) for high precision comparison calibrations of thermometers. Over time, improvements in technology lead to increased accuracies of transfer standards for temperature measurements, such as standard platinum resistance thermometers. Therefore, the performances of the calibration baths and furnaces used for comparison calibration are becoming a limiting factor in a process of temperature scale dissemination. Since the time variation of metrological characteristics of temperature regulated zones (gradients, stability, and repeatability) adds a significant contribution to the total calibration uncertainty, precise and accurate evaluation of those characteristics is of very high importance. The method described in this paper was used for evaluation of characteristics of liquid bath with the equalizing block. The bath was filled with water, and its characteristics were tested in a temperature range from 20 °C to 80 °C. The results of the tests indicate that combined expanded uncertainties of the bath lie in the range between 4.3 mK and 10.7 mK.

thermometry; calibration bath evaluation; thermometers; comparison calibration

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