Vasylkiv N. Rising of temperature measurement precision by thermocouples during the expluatation

The dissertation is devoted to the rising of exactness of temperature measurement by thermocouples, which have considerable, purchased in the process of the continuous exploitation at high temperatures thermo-electric heterogeneity of electrodes. The properties of error are probed the purchased thermo-electric heterogeneity of thermocouples are probed in our work and the mathematical model of electrodes thermocouples of K-type drift are developed, that describes dependence of drift from their temperature of exploitation and current temperature of thermocouples areas at the fixed times of exploitation. It allowed to identify the most dangerous conditions of thermocouples exploitation from the point of view of error from the purchased heterogeneity, to classify the methods of correction of drift of thermocouples transformation functions from the point of view of error influence, and also to offer the new method of correction of this error. Properties of the offered method of correction are probed, it is shown that it allowed to decrease influence of the purchased heterogeneity on the result of measuring in 3-6 times. The structure of temperature measurement precision system and stand of metrological verification of thermocouples with the considerable purchased thermo-electric heterogeneity are developed, and they are suitable for realization of the offered method of correction. Keywords: thermocouple, drift of transformation functions, thermo-electric heterogeneity, error correction.