1. Q: Why is there such a big difference between the material temperature and the cold well temperature when the glass cover and the cold well are connected up and down?
A: because under vacuum, heat can no longer be transmitted through air.
2. Q: Why is the compressor always on during vacuum pumping?
A: keeping the freeze dryer at a low temperature is conducive to the continuous sublimation of the water in the sample after freezing. The water vapor generated in the process will be frozen and stored again in the cold trap, and defrost after freeze-drying.
3. Q: why is the material temperature at the end of freeze-drying almost the same as or even higher than the ambient temperature?
A: Although the internal heat cannot be conducted up and down by air in the vacuum state, the material tray, diaphragm and housing are connected, and they can transfer heat through themselves. In addition, the operation of the machine generates some heat, so the material temperature comes from this. The cold trap temperature is also produced by the compressor acting on the cold trap wall.
4. Q: can the end time of freeze-drying be determined by the material temperature?
A: No. The time Zui suitable for freeze-drying should be determined based on experience because the material temperature only represents the probe sensor temperature, which may have errors with the actual situation. However, the material temperature can be used as an auxiliary judgment condition. After all, the temperature of the material itself will start to rise slowly only when the moisture sublimation rate in the material is reduced to a degree that is insufficient to offset the increase of the ambient temperature on the material temperature.
5. Q: do you still need to keep the compressor on at the end of freeze-drying to defrost?
A: after freeze-drying, the compressor must be turned off first, and then press the defrosting key to press it. Otherwise, if the compressor is turned on all the time, the temperature in the cold well will not rise and the ice will not melt.
