Open AccessCalibration bath uncertainty in precision temperature measurements
Author(s) -
Maja Đekić
Publication year - 2019
Publication title -
glasnik hemičara i tehnologa bosne i hercegovine
Language(s) - English
Resource type - Journals
eISSN - 2232-7266
pISSN - 0367-4444
DOI - 10.35666/ghtbh.2019.53.02
Subject(s) - calibration , homogeneity (statistics) , temperature measurement , temperature gradient , measurement uncertainty , stability (learning theory) , materials science , mechanics , environmental science , thermodynamics , physics , computer science , mathematics , statistics , meteorology , machine learning
Calibration baths are widely used in many laboratories worldwide for the calibration of thermometers by comparison. They come in different shapes and sizes and use different media (water, alcohol, silicon oil etc.), but a certain nonuniformity of theused media is always present. During precision temperature measurements, uniformity (homogeneity and temporal stability) of a calibration bath is of the utmost importance since its contribution to total measurement uncertainty is the largest. The temperature gradient can be described as a change of temperature at different positions inside the bath working volume. Temporal temperature stability depends on many factors such as: the bath temperature, control system, bath construction and the flow of the used media inside the bath, just to name a few. In this paper, we investigate uniformity of a cylindrical calibration bath. Homogeneity is determined by measurement of axial and radial temperature gradient inside the bath. Stability is examined by observation of the change in temperature reading during certain period of time. The obtained results are compared with manufacturer specification and can be used for determination of calibration bath contribution to total measurement uncertainty during calibration of thermometers.