The principle of freeze dryer, what is vacuum freeze dryer?

First, let’s learn about vaporization and sublimation. The process of a substance changing from liquid phase to gas phase is called vaporization. For water, if the ambient temperature is greater than 0 degrees and the water vapor partial pressure is less than the saturated vapor pressure of water, vaporization can proceed smoothly. Most current drying methods work according to this principle. The process of matter changing from solid phase to gas phase is called sublimation. If the ambient temperature is less than 0 degrees, water exists in the form of solid ice, and the partial pressure of water vapor in the environment is less than the saturated vapor pressure of water on the ice surface, then sublimation can proceed smoothly. If the partial pressure of water vapor in the environment is greater than the saturated vapor pressure of water on the ice surface, the water vapor condenses into ice or frost. We call this sublimation, which is the opposite process of sublimation.

What is freeze-drying? It is a common concept that after washing clothes, the clothes should be dried in a higher temperature, ventilated and dry environment. The higher the ambient temperature and the higher the air dryness, the faster the clothes will dry. But in severely cold areas, people find that washed clothes will dry out if they are left in the sun where the ice and snow never melt. In addition, people have also found that unpackaged food placed in cold storage and refrigerator freezers is frozen hard, but the surface is dry. These are freeze-drying phenomena.

What is freeze-drying? It is a common concept that after washing clothes, the clothes should be dried in a higher temperature, ventilated and dry environment. The higher the ambient temperature and the higher the air dryness, the faster the clothes will dry. But in severely cold areas, people find that washed clothes will dry out if they are left in the sun where the ice and snow never melt. In addition, people have also found that unpackaged food placed in cold storage and refrigerator freezers is frozen hard, but the surface is dry. These are freeze-drying phenomena. The use of vacuum freeze dryer Next we will understand the principle of freeze-drying. As we said before, when the temperature is 0 degrees, water is just at the freezing point. At this time, the water is in the three states of liquid, gas and solid. We call this point Triple point of water. When the temperature goes up, water appears in two phases: vapor and liquid; when the temperature goes down, water appears in two phases: vapor and solid. When water freezes into ice, we know from the previous study that as long as the partial pressure of water vapor in the environment is less than the saturated vapor pressure of ice at the corresponding temperature, the ice will directly change from solid to vapor and undergo a drying process. We call this process It is called sublimation drying, and the phenomenon of ice changing directly from solid to gas is called sublimation. We dry the material while it is frozen. During the drying process, the ice does not melt. The process in which the ice vaporizes directly from the solid state and dries is called freeze-drying (referred to as freeze-drying).

Next, let’s understand the principle of freeze-drying. As we said before, when the temperature is 0 degrees, water is just at the freezing point. At this time, water is in the three states of liquid, gas, and solid. We call this point the triple point of water. When the temperature goes up, water appears in two phases: vapor and liquid; when the temperature goes down, water appears in two phases: vapor and solid. When water freezes into ice, we know from the previous study that as long as the partial pressure of water vapor in the environment is less than the saturated vapor pressure of ice at the corresponding temperature, the ice will directly change from solid to vapor and undergo a drying process. We call this process It is called sublimation drying, and the phenomenon of ice changing directly from solid to gas is called sublimation. We dry the material while it is frozen. During the drying process, the ice does not melt. The process in which the ice vaporizes directly from the solid state and dries is called freeze-drying (referred to as freeze-drying).