Working Principle of Vacuum Freeze Dryer Machine:
By principle of sublimation, the complete frozen product is heated in a vacuum condition of drying chamber. The ice in the product becomes vapor directly, no melting in the procedure. The vapor in the sealed chamber is condensed by vapor condenser on which temperature is much lower. So the vapor gets frosted soon and accumulated on the surface of vapor condenser. Continuously the moisture in the product is removed to vapor condenser, finally the product is dried, and the vapor condenser is full of ice. At the end of a freeze drying cycle, the ice will be melted by water which called defrosting.