Air or inert gas is introduced from below, through a special diffusion plate, into a retort with fine-grain aluminum oxide, mixing intensively with the solids. This creates a fluidized bed in the measuring chamber (retort) where the Al2O3 solid particles move at low gas velocities without significant kinetic energy. The fluidized bed in the retort conducts heat extremely well and because of its mass possesses an enormous heat capacity. Test specimens such as thermocouples or other sensors can be immersed without problems. Video / Technical Animation
The calibration and test system THERMOCAL is heated indirectly via electric heaters and can be used over a large temperature range from 50 °C to 1100 °C with top precision. The precise calibration process of THERMOCAL, which can be reproduced at any time, is handled by an electronic controller with NiCrNi thermocouples and direct measured value indication.
Many times an oil bath, which soils the temperature measuring instruments, is used for conventional calibration. The Al2O3 powder used for the THERMOCAL calibration bath, by contrast, is odorless, non-toxic, non-flammable, neither corrosive nor aggressive and particularly clean in handling and above all, it does not leave any oil or salt residues on the test specimen.