general drying oven
Both adopt a method of heating the wall surface of the vacuum chamber first, and then radiant heating by the wall facing the workpiece. In this way, the temperature sensor of the temperature control meter can be arranged on the outside wall of the vacuum. The sensor can accept convection, conduction, and radiant heat simultaneously. The glass rod thermometer in the vacuum chamber can only receive radiant heat, and because the blackness of the glass rod cannot reach 1, a considerable part of the radiant heat is refracted, so the temperature value reflected by the glass rod thermometer is definitely lower than the temperature reading of the meter. . In general, it is normal to have a difference between the temperature reading of the meter and the reading of the glass rod thermometer within 30 °C at 200 °C. If the temperature sensor of the temperature control instrument is placed in the vacuum chamber, the difference between the temperature value of the glass rod thermometer and the temperature reading of the meter can be appropriately reduced, but it is impossible to eliminate, and the sealing reliability of the vacuum chamber increases a possible unreliable link. . If you do not want to see this difference from the practical point of view, you can use the display correction function unique to the temperature control instrument.
electric drying oven
Temperature uniformity parameters are provided: the natural convection oven is the upper limit of the operating temperature multiplied by 3%, and the forced convection oven is the upper limit of the operating temperature multiplied by 2.5%. However, the electric vacuum drying oven does not have a temperature uniformity parameter. Why is this? The possibility of the gas temperature in the vacuum drying chamber to make the temperature of the working chamber uniform is almost gone. Therefore, conceptually we can no longer use the temperature uniformity defined by the usual electric (blast) drying oven to the vacuum drying oven. It is also meaningless to set this indicator under vacuum. The amount of thermal radiation is inversely proportional to the square of the distance. For the same object, the radiant heat received at 20 cm from the heated wall is only 1/4 of 10 cm from the heated wall. big difference. This phenomenon is warm when the sun is shining in the winter, and the sun is not warm. It is a truth that the sun is not cold. Because the vacuum drying oven is difficult to make the radiant heat of each point in the three-dimensional space of the studio uniform and lacks an authoritative evaluation method, it may be that the temperature uniformity parameter is not included in the standard of the electric vacuum drying oven. s reason.
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