Why Vacuum Drying Oven Must Be Vacuumed First

Vacuum drying ovens are widely used in research applications such as biochemistry, chemical pharmacy, medical and health, agricultural research, environmental protection, etc., mainly for powder drying, baking, and disinfection and sterilization of various glass containers. It is especially suitable for fast and efficient drying treatment of dry heat sensitive, easily decomposed, easily oxidized substances and complex composition items.
In the process of use, why must the vacuum drying oven be vacuumed first and then heated up, instead of first heating up and then vacuuming? The specific reasons are as follows:
1. The product is put into the vacuum drying oven and vacuumed to remove the gas components that can be removed from the product material. If the product is heated first, the gas will expand when heated. Due to the very good sealing of the vacuum drying oven, the huge pressure generated by the expanding gas may burst the tempered glass of the observation window. This is a potential danger. Operate according to the procedure of vacuuming first and then heating, so that this danger can be avoided.
2. If operate according to the procedure of heating first and then vacuuming, when the heated air is pumped out by the vacuum pump, the heat will inevitably be carried to the vacuum pump, which will cause the vacuum pump to rise too high in temperature and possibly reduce the efficiency of the vacuum pump.
3. The heated gas is directed to the vacuum pressure gauge, and the vacuum pressure gauge will generate a temperature rise. If the temperature rise exceeds the specified operating temperature range of the vacuum pressure gauge, it may cause the vacuum pressure gauge to produce value errors.
The correct use method of the electric vacuum drying oven: first vacuum and then heat up, after reaching the rated temperature, if the vacuum is found to decrease, then vacuum it appropriately again. This is beneficial to extend the service life of the equipment.