The reason of thermocouple measurement error

In the working process of the thermocouple, it was found that, in some cases, the measurement work there's always some error. What are the main factors that affect the error content? To this, we will give some answer in this thesis, hope to be able to help them better understand thermocouple this product.

aiming at this problem, we can consider to have the influence factors of seven aspects, and then we will be introduced one by one. , it is caused by unstable thermocouple thermoelectric properties. After a period of use, especially the influence of the environment, its performance will have some change, resulting in the measurement of temperature and real temperature exist certain differences. Second, it is because of the irregularity, is mainly refers to its thermal uniformity of electrode materials.

in addition to the above two problems, if the temperature of the measuring point is different, so also causes a certain differences. In fact, at the time of installation of thermocouple, temperature measuring point selection is a critical problem, we must give full consideration to, and then choose the representative temperature measuring point. The fourth is the influence of the response time. Normally, when the temperature of the measured object and the temperature measuring element to maintain consistent, the temperature of the temperature measuring element will remain stable.

in addition, you also need to consider the heat radiation problem. As we know, besides is heat transfer, the rise of temperature and thermal radiation can also lead to temperature change. So, when using thermocouple measuring temperature in the furnace, furnace high temperature object will produce certain thermal radiation, temperature rise due to forming error. In addition, if the environment temperature is higher, its long-term under such conditions, it can cause protecting tube thermal impedance increases, thus increase the measuring error.

the aspects should be considered a thermocouple wire is heterogeneity, resulting in error. So, in the production and processing, we need to pay attention to this problem, try to avoid this problem.