The “Temperature Amplifier”: an Innovative Application of Pressure‐Controlled Heat‐Pipes for Calibration of PRTs and Thermocouples

At high temperature (from 600 °C to 962 °C) calibration by comparison of platinum resistance thermometers (PRTs) is limited by the instability and the reliability of the standard high‐temperature PRT and by the temperature uniformity in the working volume of furnaces equipped with comparison blocks. To improve its calibration‐comparison capability, BNM‐INM is studying the possibility of connecting several pressure‐controlled heat‐pipes, filled with different working fluids, simultaneously to the same pressure control system. The experimental apparatus, called a “temperature amplifier,” is composed of three heat‐pipes filled with sodium (Na), potassium (K), and dodecane (Do).