Freeze drying is a drying technology utilizing the precept of sublimation. The product obtained by freeze-drying is called a lyophilizer, and the process is called lyophilization. The substance is always in a low temperature freezing state before drying, and the ice crystals are evenly distributed within the substance. The sublimation process will not trigger condensation because of dehydration, and keep away from unwanted aspect effects similar to foaming and oxidation attributable to water vapor. The dry substance is porous within the type of a dry sponge, the volume is unchanged, and it is simply soluble in water and returns to its original state. Physicochemical and organic denaturation of dry substances is prevented to the greatest extent potential.
How mini freeze dryer works：
The working precept of the scientific freeze dryer is to first freeze the dried items to below the triple point temperature, after which instantly chic the solid water (ice) within the gadgets into water vapor beneath vacuum situations, take away them from the stems and dry the items. After pre-processing, the materials are despatched to the quick-freezing bin for freezing, then sent to the drying bin for sublimation and dehydration, after which packed within the post-processing workshop. The vacuum system establishes low-pressure circumstances for the sublimation drying chamber, the heating system supplies latent heat of sublimation to the fabric, and the refrigeration system supplies the required cooling capability to the cold entice and drying chamber. The tools adopts high-efficiency radiation heating, and the fabric is heated evenly; it adopts a hig-efficiency water-trapping cold trap, which can realize speedy defrosting; adopts high-efficiency vacuum unit, which can realize oil-water separation; adopts parallel centralized refrigeration system, multi-channel on-demand cooling, working circumstances It is stable and useful to energy saving; synthetic intelligence management is adopted, with excessive control precision and convenient operation.
Types of freeze dryers:
1)Bell sort of freeze dryer
The freeze-drying chamber and the chilly entice are separate upper and decrease structures, and the freeze-drying chamber is provided with a pre-freezing perform. This sort of scientific freeze dryer requires guide operation when the material is transferred to the drying course of after pre-freezing. Most of the experimental scientific freeze dryer are of the bell jar kind, which is straightforward in construction and low in cost. Most of the freeze-drying chambers use a clear plexiglass cowl, which is handy for observing the freeze-drying of supplies.
Bell sort of freeze dryer machine has precise temperature and pressure control for optimal freeze-drying conditions. It comes with modular trays for easy loading and unloading, suitable for a variety of products and batch sizes
2) In-situ freeze dryer
The freeze-drying chamber and the chilly lure are two independent chambers. The shelf within the freeze-drying chamber has a refrigeration perform. After the fabric is placed within the freeze-drying chamber, the pre-freezing and drying means of the fabric does not require handbook operation. The manufacturing process of this type of freeze dryer is complex and the manufacturing value is high, but the in-situ freeze dryer is the event path of the freeze dryer, which can be explored for the freeze-drying process, particularly for the freeze-drying of medicines, biological products and other special products.
ZZKD is a professional manufacturer of drying equipment, in addition to freeze dryers, we also have drying ovens, such as vacuum drying oven dzf-6020.
Freeze Dryer Selection Guide：
1) Freeze-dried area
The number in the freeze-drying machine model represents the freeze-drying space of the freeze-drying machine of this model. For instance, the freeze-drying area of the LGJ-18C experimental scientific freeze dryer machine is 0.18㎡. The user ought to determine the lyophilizer with a large freeze-drying area by calculation based on his own wants. For instance, every batch of products with a liquid quantity of 1.eight kilograms (liters) needs to be freeze-dried, and the material is loaded in a material tray, and each tray is loaded with a thickness of 10 mm, then the load area of the freeze-dried layer could be calculated:
A(area, ㎡)=V(volume, m)/H(height, m)=0.0018m/0.01m=0.18㎡
That is, a freeze dryer with a plate load area of 0.18 sq. meters needs to be chosen.
2) Cold entice temperature
The chilly lure is a tool for capturing water in the freeze-drying process. Theoretically, the lower the temperature of the cold trap, the stronger the water trapping capacity of the cold entice, but the lower the temperature of the chilly lure, the upper the refrigeration necessities, and the higher the machine price and working cost. The chilly lure temperature of the experimental collection freeze dryer primarily has a quantity of grades corresponding to about -45°C, about -60°C, and about -80°C. The freeze-drying machine with a cold lure temperature of -45°C is suitable for some merchandise which would possibly be straightforward to freeze-dry. The freeze-drying machine with a cold trap temperature of about -60°C is appropriate for freeze-drying of most products. Freeze-drying with a cold trap temperature of -80°C It is suitable for lyophilization of some special merchandise. The experiment of the impact of cold lure temperature on water trapping capability reveals that the water trapping capacity is significantly improved when the cold lure temperature drops from -35°C to -55°C. Therefore, within the absence of particular necessities, it is an ideal selection to use a chilly lure temperature of about -60 °C.
3) Cooling rate
The cooling price reflects the cooling capability of the refrigeration system. Under no-load conditions, the temperature of the cold entice ought to reach the minimum temperature specified within the index within 1 hour. For example, for a scientific freeze dryer with a chilly entice temperature ≤ -60 °C, the machine starts timing from the time the machine is turned on for refrigeration, and the time for the chilly entice temperature to succeed in -60 °C should not exceed 1 hour.
4) Ultimate vacuum degree
The final vacuum diploma reflects the leakage of the experimental scientific freeze dryer and the pumping effectivity of the vacuum pump. The vacuum degree of the freeze-drying field. In the past, the upper the vacuum diploma, the better. The present viewpoint is that the vacuum diploma should be inside an inexpensive vary. The vacuum degree is simply too excessive, which is not conducive to warmth transfer, and the drying velocity decreases, however in any case, the no-load limit vacuum degree of the freeze-drying box ought to reach more than 15Pa.
5) Vacuum time
The evacuation speed of the freeze-drying field should be pumped from atmospheric strain to 15Pa inside half an hour.
