1. The working principle of thermocouple thermometer
A thermocouple thermometer is a device that converts temperature into a voltage signal. It consists of two different metal wires (thermocouple wires) connected together to form a temperature-sensitive point at the joint. When the temperature at the joint changes, the electromotive force of the two metals also changes, resulting in a certain voltage signal output. Therefore, we can determine the temperature at the joint by measuring the voltage signal output by the thermocouple, and indirectly measure the temperature being measured.
2. Thermocouple thermometer temperature calibration steps
Preparation: First of all, check whether the detection instrument of the thermocouple thermometer is normal, including multimeter, thermometer, etc., if it is not normal, it needs to be replaced or repaired in time. At the same time, check whether the wiring of the thermocouple thermometer is properly connected.
Temperature calibration: Insert the thermocouple thermometer and the standard thermometer into the temperature calibration instrument at the same time, and calibrate each temperature point according to the standard temperature value. In general, calibration is performed at 6 fixed temperature points, including etc. At each temperature point, the temperature is stabilized, and then the thermocouple output voltage is measured and compared with the temperature value of a standard thermometer to determine the temperature difference between them.
Calibration adjustment: When it is found that the temperature value output of the thermometer is significantly different from the temperature value of the standard thermometer, calibration adjustment is required. The adjustment method is generally adjusted by rotating the adjustment knob or replacing the calibration resistor until the thermometer output value matches the standard thermometer temperature value.
Finished product inspection: After completing the calibration, the finished product inspection is required to check whether the thermometer can work stably and accurately.
3. Precautions for thermocouple thermometer temperature calibration
Calibration environment requirements: The environment needs to be stable during calibration, and the temperature change should not exceed 1.
Temperature calibration sequence: In general, calibration should be carried out in order from low to high to avoid the accumulation of errors.
Preparation before calibration: Before calibration, the thermocouple thermometer needs to be heated to room temperature (or 0) to ensure that the thermocouple and the specimen temperature are consistent and improve the accuracy of calibration.
Temperature calibration frequency: According to factors such as the frequency of thermocouple use and the working environment, temperature calibration should be carried out at least once a year to ensure the measurement accuracy of the thermocouple thermometer.
Expiration date: After a period of use, the thermocouple wire of the thermocouple thermometer is easy to deteriorate and the accuracy will also decrease, so it needs to be replaced regularly.