In actual use, the thermocouple measurement error is embodied in several aspects.
1, the thermocouple of non-uniform degree error
because of uneven thermocouple wire sizes, thicknesses, or material is not pure, density, PH value, makes the temperature of the thermocouple -
Electromotive force relationship and unified indexing table within a certain error, the error must not exceed the relevant standards.
2, water purity,
in thermocouple cold end reach real freezing point, the material temperature, the error caused by, for precision measurement, the demands made of pure water in ice water to experiment (
Note: pure water is purified water, not drinking water)
3, the polarity between
between the poles, thermocouple, and between the earth and bad insulation or measuring instrument accuracy is not high, will result in thermoelectric power loss, affect the accuracy of measurement.
4, high temperature environment
under the environment of high temperature, thermocouple will have effect, can lead to accuracy is not high, if the high temperature for a long time, more can lead to the oxidation.
The error is bigger.
5, thermal radiation, depth, flow
too deep, too fast airflow, heat radiation is too strong will cause error.
thermocouple in the actual temperature measurement of the performance was very good.
Based on these features, in addition to pay attention to the environment and test items, their material improvement is also very important, while receive the limitations of technology and cost, but refrigeration equipment, can be improved and the application in the high-end models.
Such as: laboratory, cold water machine, rushing the lyophilizer, ultra-low temperature freezer, etc.
technology laboratory, constant innovation, found a lot of technical information used in practice.