Freeze dryer and lyophilizer heating method
When you use one Freeze Dryer, one important preparation work need to do is to set its freeze drying curve or recipe, many steps in one recipe with its specified heating temperature, lasting time, maybe also have vacuum degree. The reason Freeze Dryer introduce heating system have several reasons:
Why need heating?
1, As know, whether normal drying or vacuum drying, the water inside raw material need absorb heat and then escape by vapor type. That means in freeze dryer, shelves module, if provide extra energy/heat, could speed up the sublimation process.
Even introduce heating system, however, in vacuum condition, heat transfer efficient is very low, so for one cycle may take several hours to several days.
2, The heating way: Electric heating and steam heating.
Shelves in freeze dryer designed hollow inside, Heat carry by medium (could be softened water or chemical like glycol/silicone oil) flow and recycle inside, exchange with frozen material, that means the heat exchange is indirect, the advantage is very small temperature tolerance for all shelves, ensure the constantly freeze dried products quality.
Electric heating mostly use for smaller models or workshop don’t have enough space support external steam boiler. The heating method cost a lot electric.
Steam heating is standard configuration for large freeze drying equipment, especially for food drying, steam heating is economic and high efficient, help reduce production cost.