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Improving the calibration services for thermocouples


The high-temperature furnaces with 3 heating zones for the calibration of thermocouples for temperatures up to 1770 °C.

At PTB, the unit of temperature is disseminated in about 50 % of all cases by calibrating noble metal thermocouples against fixed points of the International Temperature Scale of 1990 (ITS-90) in the temperature range between 0 °C and 1600 °C. To this end, the phase transitions between the solid and the liquid state (melt) or between the liquid and the solid state (freeze) of pure metals, which occur at well-defined temperatures, are used. In 2016 and 2017, two new fixed-point furnaces for use with fixed-point crucibles filled with the pure metals silver, copper, palladium and platinum were commissioned and metrologically characterized. With the new high-temperature furnace (see figure), it is now possible to use, in particular, the melting temperatures of the noble metals palladium (1553 °C) and platinum (1769 °C). These metals are available in miniature crucibles. This allows the extension of the temperature range for the calibration of special thermocouples to 1769 °C.



F. Edler, 7.41, E-Mail: Opens window for sending emailFrank.Edler(at)ptb.de

P. Ederer, 7.41, E-Mail: Opens window for sending emailPetra.Ederer(at)ptb.de