The causes of thermocouple thermal inertia and solution1

Temperature sensor to temperature measurement, mainly is the thermal resistance and thermocouple inside. So hot laziness of the temperature sensor, in fact, the temperature sensor inside the thermal resistance and thermocouple thermal inertia. What are the causes of thermocouple thermal inertia? How to solve the thermal inertia of thermocouple again?

because of thermal resistance and thermocouple thermal inertia instrument behind the change of the measured temperature, indicating value of this influence is particularly acute in rapid measurement. So should be used as thermal electrode is fine, protecting tube diameter smaller thermal resistance and thermocouple, temperature measuring environmental permits, even protecting tube can be taken.

thanks to measure hysteresis, with thermal resistance and thermocouple to detect the temperature fluctuations of the amplitude of the furnace temperature fluctuation amplitude of the small. Measurement lags behind, the greater the heat resistance or thermocouple fluctuation amplitude is smaller, and the actual temperature difference.

when using time constant of thermocouple temperature or temperature control, instrument display temperature fluctuation is small, but the actual furnace temperature fluctuations can be quite large. In order to accurately measure temperature, should choose small time constant of thermal resistance and thermocouple.

time constant is inversely proportional to the heat transfer coefficient, heat and thermal resistance and thermocouple on the density and specific heat is proportional to the diameter, material, such as to reduce the time constant, in addition to the increased heat transfer coefficient, the most effective way is to try to decrease the size of the hot end.

use, usually USES the material with good thermal conductivity, thin, small diameter of the tube wall to protect casing. In the precision of temperature measurement, using unprotected bare wire casing thermal resistance and thermocouple, thermocouple easy damaged, should be timely correction and replacement.

temperature sensor error caused by the thermal inertia has great effect on the measured value in the measurement, especially in the precision measurement of thermal inertia, it is important to note that sensor when we try to avoid the error due to thermal inertia or take appropriate compensation to weaken the error.

more high-quality sensors at https://www. rtdcn。 Com /

key words: thermal resistance, thermocouple, thermal resistance, platinum resistance, PT100, PT1000, pressure sensor and digital temperature sensor