In the thermocouple calibration process, the selection and maintenance of reference standards are important links to ensure calibration accuracy.Selecting an appropriate reference standard thermometer is crucial. It is usually determined according to the type of thermocouple, the calibration temperature range and the required accuracy level. For example, for high-temperature calibration with high accuracy requirements, a platinum resistance thermometer may be selected as the reference standard because it has high stability and accuracy at high temperatures. For some calibration in the medium and low temperature range, a glass liquid thermometer or a thermocouple standard may also be selected. When selecting, it is necessary to ensure that the accuracy of the reference standard is higher than the accuracy requirement of the calibrated thermocouple, and its measurement range can cover the calibration temperature range of the thermocouple.
The maintenance of the reference standard thermometer cannot be ignored. It needs to be regularly sent to a professional metrology institution for calibration to ensure its accuracy. The calibration cycle is generally determined according to its stability and frequency of use. For a reference standard with good stability and low frequency of use, the calibration cycle can be relatively long, but generally it should not exceed the specified maximum cycle. During the calibration interval, the reference standard should be properly stored to avoid physical damage, temperature shock or humidity influence. For example, it should be placed in a special constant temperature and humidity box, and shockproof measures should be taken during transportation.
In addition, the use records of the reference standard should also be carefully preserved. The records include information such as the time of each use, the measured temperature points, and the measurement results. These records help to analyze the performance change trend of the reference standard, timely discover potential problems, so as to arrange calibration or replacement of the reference standard in advance when necessary, thus ensuring that the thermocouple calibration work is always carried out under a reliable reference standard and improving the accuracy and credibility of calibration.
