Excessive temperature overshoot refers to the phenomenon that when the drying oven is started for the first time, the working room temperature exceeds the set temperature by more than 5 ℃, and then slowly reduces and stabilizes at the set temperature. Some pharmaceutical, biological, chemical, food, electronic and other industries are more sensitive to this phenomenon.

Although there is no limit index of temperature overshoot in the standard of electric blast drying oven, the electric heater manufacturer pays attention to the user's opinion and specially designs the electrical circuit to meet the user's requirements in this respect. With the continuous improvement of control technology, the temperature overshoot of electrothermal blast drying oven has been generally controlled below 2 ~ 3 ℃. Through fine adjustment, the instrument reading can not even show the phenomenon of temperature overshoot in ideal state. It is impossible to eliminate temperature overshoot completely. There is a way to make the temperature overshoot acceptable.

There are three options for users to choose from:

① Two stage temperature rise method: first set the instrument temperature at 5-10 ℃ from the required temperature (the specific difference is appropriate, the user can determine according to the ambient temperature and the number of samples), and then reset the instrument temperature to the required drying temperature.

② Empty box constant method: first, the temperature of the working room is raised to and stabilized at the required drying temperature, and then the sample is quickly put into the working room. This method should pay attention to protect the operator from scalding. More attention should be paid to the possible new danger caused by the volatiles volatilizing too fast.