Three often ignore the thermocouple used

Thermocouple bent: because the thermocouple wire is relatively soft, so it is easy to deformation, when accidentally silk in the plastic deformation of the city, such as folds and distorted the thermocouple wire will happen corresponding stress, at the same time also to the thermocouple on the characteristics of change, will lead to the thermocouple severely influence on the accuracy of measurement. So before using thermocouple for verification, I must be straight wire. Thermocouple wire polluted: if contaminated thermocouple wire happen, or oxidation, lead to the thermocouple wire surface appear the phenomenon of light and dark, then hot electrode is very unstable, and measurement accuracy is more difficult to control, so need in a timely manner to clean electrode pollution. Three, insulation resistance affected: when the thermocouple under high temperature, the whole of the insulation resistance will sharply declining due to the temperature rise, so will appear the phenomenon of leakage current, the current will take advantage of the insulation resistance, directly down into the instrument, prompted the instrument on the instructions is not stable, or is a severe error phenomenon. So we before furnace charging of thermocouple, must the associated test of insulation resistance can not be ignored, only to meet the requirements of the test, to ensure the normal use of thermocouple.