How to Calibrate A Chamber Furnace

Temperature reading on the controller’s PV screen (temperature value marked as PT) may different from the actual temperature at furnace chamber center (temperature value marked as AT) due to thermocouple’s location and various specifications such as TC type, diameter, length, heating rate and response time).

In order to achieve accurate temperature measurement inside the chamber during heating, you shall calibrate the furnace (muffle furnaces or tube furnaces) during the steady-state (Normally, the steady state can be reached around 30 minutes) and then set the temperature offset value accordingly (A function relates to “SC”/”Cor”parameter in the control unit). Please follow the steps below:

  1. The calibration can be done by using a portable handhold thermometer and thermocouple with compensating wire. Insert the external thermocouple from a reserved thermocouple hole or from the exhaust pipe (for tube furnace, insert from the one side through the ceramic plug to the tube center), make sure the thermocouple reach the effective working area of the furnace chamber.
  2. Connect the thermocouple to the handhold thermometer, be attention to choose the correct thermocouple type
  3. Heating the chamber furnace to desired working temperature and then hold for 1 hour until the steady-state reached.
  4. Record temperature difference between PV value (PT) and external thermometer’s actual temperature (AT) namely PT-AT or AT-PT
  5. Adjust the temperature offset parameter “SC”/”Cor” according to the temperature difference.

All the chamber furnaces like muffle furnaces, tube furnaces from Program Thermal Tech will be calibrated before delivery, we will make sure the exact temperature reading. Programtherm furnaces make your heat treatment more successful.

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