For this purpose, we created a 1300mm long, three-zone tube furnace. To ensure uniform radial temperature distribution, an isothermal block was designed to fit inside the tube furnace, allowing the long thermocouple to make closed contact with the isothermal block body. Axial uniformity was achieved through the three-zone design.

The furnace length includes five holes that permit the insertion of an equal number of calibration reference thermocouples. These reference thermocouples also pass through corresponding holes in the isothermal block body. The reference thermocouples face and measure directly at the same points as the five calibration thermocouple junctions. Both the reference thermocouple and the calibration thermocouple probe junctions are well surrounded by, and in close contact with, the isothermal block mass, ensuring they are exposed to the same temperature.

Thermansys can provide custom designed thermocouple calibration systems upon request for all types and lengths of thermocouples.