The vacuum drying oven has no temperature average parameter

The natural convection drying oven is the maximum office temperature multiplied by 3%, and the forced convection drying oven is the maximum office temperature by 2.5%. Only the electric heating vacuum drying oven does not set the temperature average degree parameter, why is this?

There is almost no possibility that the office temperature can reach an average temperature due to the thermal movement of the gas in the vacuum drying oven. Because of this, conceptually, we can no longer apply the definition of the temperature average degree specified by the general electric heating (blast) drying oven to the vacuum drying oven. It is meaningless to set this indicator under vacuum conditions. The amount of thermal radiation is inversely proportional to the square of the distance. The same object, 20cm away from the heating wall, receives only 1/4 of the radiant heat that is 10cm away from the heating wall. The difference is very big. This phenomenon is the same as the timing of sun exposure days in winter. The side that is exposed to the sun is warm and the side that is not exposed to the sun is colder. Because it is difficult for the vacuum drying oven to make the average radiant heat of each point in the three-degree space of the office exactly the same in structure, it also lacks authoritative evaluation methods. This may be because the standard for electric heating vacuum drying ovens does not set the average temperature The reason for the variable.