26-05-2011, 07:39 AM
One of my first tasks I was taught as a lab technician in a metallurgy lab when I was 16 was to use a thermocouple bridge to calibrate optical pyrometers on salt bath furnaces. This was done first thing every morning using an old wooden cased instrument and a metal sheathed thermocouple that was dipped into the molten salt. The salt was at 1280 degrees C for heat treating high speed steel and the metal sheaths for the T/Cs had quite a short life.
