A thermocouple temperature sensor is actually an energy converter that converts thermal energy into electrical energy and uses the resulting thermoelectric potential to measure temperature. However, due to many variables in the measurement, it is easy to affect the measurement results, so it is necessary to understand these influencing factors. Then, the editor will introduce to you what are the factors that affect the measurement of thermocouple temperature sensor?

1. Insertion depth: The error caused by heat conduction is related to the insertion depth. The insertion depth is related to the material of the protective tube. Because of its good thermal conductivity, the metal protection tube should be inserted deeper, and the ceramic material has good thermal insulation performance and can be inserted shallower. For engineering temperature measurement, the insertion depth is also related to whether the measurement object is still or flowing. For example, the measurement of the temperature of flowing liquid or high-speed airflow will not be limited by the above, and the insertion depth can be shallower, and the specific value should be determined by experiment.

2. Thermal response time: The thermal response time mainly depends on the structure and measurement conditions of the sensor, and the difference is very large. For gaseous medium, especially static gas, it should be kept for at least 30min to reach equilibrium; for liquid, the fastest should be more than 5min. For the measured place where the temperature is constantly changing, especially the instantaneous change process, the whole process is only 1 second, the response time of the sensor is required to be in the millisecond level.

3. Increased thermal impedance: For thermocouple temperature sensors used at high temperatures, if the measured medium is gaseous, the dust deposited on the surface of the protection tube will be melted on the surface, increasing the thermal impedance of the protection tube; The medium is melt, and slag will be deposited during use, which not only increases the response time of the thermocouple, but also lowers the indicated temperature.

4. Heat radiation: In general, in order to reduce the error of heat radiation, the heat conduction should be increased, and the temperature of the furnace wall should be as close as possible to the temperature of the thermocouple. In addition, the installation position of the thermocouple should avoid the thermal radiation emitted from the solid as much as possible, so that it cannot radiate to the surface of the thermocouple, and the thermocouple preferably has a thermal radiation shielding sleeve.

Through the understanding of the above content, we clearly know that there are many factors that affect the measurement of thermocouple temperature sensor. Among them, the four factors of insertion depth, response time, thermal impedance increase, and thermal radiation are the main factors. I hope the above content can be helpful to everyone. helped.