In thermocouple calibration work, temperature stability is an extremely critical factor. Whether a calibration furnace or a constant temperature bath is used as the temperature source, it must be ensured that it can provide a stable and uniform temperature environment.
For a calibration furnace, the performance of its heating elements and the accuracy of the control circuit directly affect temperature stability. High-quality heating elements can quickly respond to changes in temperature settings, and after reaching the set temperature, the temperature fluctuation can be maintained within a very small range through an accurate control circuit. For example, some advanced calibration furnaces adopt intelligent temperature control technology, and their temperature fluctuation can be controlled within ±0.05℃, which is crucial for high-precision thermocouple calibration.
A constant temperature bath relies on a liquid medium to maintain temperature stability. The specific heat capacity of the liquid is relatively large, which can buffer the interference of external factors on temperature to a certain extent. However, a constant temperature bath also needs to be equipped with a high-precision temperature sensor and a good stirring device. The temperature sensor monitors the temperature in the bath in real time. Once it is found that the temperature deviates from the set value, the heating or cooling device will be activated for adjustment, and the stirring device ensures the uniform distribution of the liquid temperature in the bath. During the thermocouple calibration process, if the temperature stability is insufficient, it will lead to a large deviation in the thermocouple measurement value, thus affecting the accuracy of calibration.
To evaluate temperature stability, the change of temperature is usually continuously monitored within a period of time, and its fluctuation range and standard deviation are calculated. Only when these indicators meet specific requirements can reliable thermocouple calibration operations be carried out.
