WORKING PRINCIPLE
The core working principle of a freeze dryer is to use a vacuum environmentto allow the moisture in pre frozen materialsto rise directly from solid ice to gaseous water vapor without passing through the liquid state, ultimately achievingdrying.This process is entirely based on the three state change characteristics of water, and is completed through three keystages.1. Pre freezing stage: Let the moisture "fix" into icePlace the materialin a low-temperature environment (usually below -40 °C) to rapidly freeze the free water and boundwater inside into small ice crystals.Rapid freezing can prevent excessive ice crystals from damaging the cellular structure or active ingredients of thematerial, which is the key to ensuring the shape, taste, and efficacy of the freeze-dried material.2. Sublimation stage: Let the ice directly "transform" into gasTransfer the frozen material into the vacuum chamber and start the vacuum pump to achieve a very high vacuum levelusually below 610Pa) inside the chamber.Under vacuum conditions, the sublimation point of ice will significantly decrease. At this time, by slightly heating thematerial (providing the energy required for sublimation), ice crystals will directly sublime into water vapor and detachrom the main body of the material.3. Analyze the drying stage: remove residual moistureAfter the sublimation stage, there is still a smallamount of bound water (usually 5% -10%e) remaining in the material,which cannot be removed by sublimationBy increasing the temperature of the shelf and maintaining a high vacuum degree, the bound water in the materialisresolved and captured, ultimately reducing the moisture content of the material to 1% -3%, meeting the requirementsfor long-term storage.Throughout the process, there is also an important step of capturing water (condensation). The water vapor generatedby sublimation will be introduced into a low-temperature water trap (usually below -50 °C) and re condensed into ice onthe inner wallof the trap to prevent the water vapor from returning to the material or damaging the vacuum pump.