Food freeze-drying machine
Functional principle
The basic principle of the freeze dryer is based on the three-state changes of water. Water has solid, liquid and gaseous states, and the three states can convert into each other and coexist. When water is at the triple point (temperature is 0.01°C, water vapor pressure is 610.5Pa), water, ice, and water vapor can coexist and balance each other. In a high vacuum state, the principle of sublimation is used to make the moisture in the pre-frozen material directly sublimate into water vapor in the ice state without melting the ice and be removed, thereby achieving the purpose of freeze drying. Freeze-dried products are sponge-like, have no drying shrinkage, have excellent rehydration properties, and contain very little moisture. After being packaged accordingly, they can be stored and transported at room temperature for a long time. Since vacuum freeze drying has unparalleled advantages over other drying methods, this technology has become more and more popular and concerned since its inception. Applications in medicine, biological products and food have become increasingly widespread. Biological products such as serum, bacterial strains, Chinese and Western medicines mostly contain some biologically active substances, and vacuum freeze-drying technology also provides a good solution for preserving biological activity.
Freeze-drying is a technology and method that uses the principle of sublimation to freeze-dry. It quickly freezes the dried material at low temperature, and then directly sublimates the frozen water molecules into water vapor to escape in an appropriate vacuum environment. the process of. The product obtained by freeze-drying is called lyophilizer, and the process is called lyophilization. The material is always at a low temperature (frozen state) before drying, and the ice crystals are evenly distributed in the material. The sublimation process will not cause concentration due to dehydration, and avoids side effects such as foam and oxidation caused by water vapor. The dry substance is porous in the shape of a dry sponge, with basically unchanged volume, and is easily soluble in water and restored to its original shape. To prevent physical, chemical and biological denaturation of dry substances.
Food Freeze Dryer Parameters
1. It has a fully automatic heating function for the shelves, monitors the temperature at any time, and has a temperature control function
2. Siemens PLC programmable control system, one-button fully automatic control, safe and stable;
3. Imported temperature control: using PID adjustment for precise temperature control;
4. The human-machine interface adopts a 7-inch standard LCD touch screen, which is simple and convenient to operate.
5. The user-friendly design operation interface allows you to follow the freeze-drying progress of items anytime and anywhere;
6. Equipped with host computer communication interface (supports remote monitoring function);
7. Control system: There are two systems, automatic and manual, which are safe, reliable, convenient and practical.
8. The voltages are: 380V and 220V.
9. Refrigeration unit: It adopts a compressor unit imported from Germany, which is safe, reliable and has stable performance.
10. Vacuum pump: Use a well-known brand vacuum pump with high pumping speed, low noise and strong filtration performance.
11. Automatically collect freeze-drying data, which can be viewed and downloaded;
12. Defrost system: non-electric heating defrost method, high safety performance and fast defrost speed;
Component
The freeze dryer is composed of a refrigeration system, a vacuum system, a heating system, and an electrical instrument control system. The main components are drying box, condenser, refrigeration unit, vacuum pump, heating/cooling device, etc. Its working principle is to first freeze the dried items below the triple point temperature, and then directly sublimate the solid moisture (ice) in the items into water vapor under vacuum conditions, and then remove them from the items to dry them. After pre-treatment, the materials are sent to the quick-freezing warehouse for freezing, then sent to the drying warehouse for sublimation and dehydration, and then packaged in the post-processing workshop. The vacuum system establishes low pressure conditions for the sublimation drying chamber, the heating system provides latent heat of sublimation to the materials, and the refrigeration system provides the required cold energy to the cold trap and drying chamber. This equipment adopts high-efficiency radiant heating, so that the material is heated evenly; it adopts an efficient water-capturing cold trap, and can achieve rapid defrost; it adopts a high-efficiency vacuum unit, and can realize oil and water separation; it adopts a parallel centralized refrigeration system, with multiple channels for on-demand cooling, working conditions Stable, beneficial to energy saving; using artificial intelligence control, high control precision and easy operation. The quality requirements for freeze-dried products are: unchanged biological activity, uniform appearance and color, full shape, firm structure, fast dissolution speed, and low residual moisture. To obtain high-quality products, you should have a relatively comprehensive understanding of the theory and process of freeze-drying. The freeze-drying process includes three stages: pre-freezing, sublimation and re-lyophilization! Reasonably and effectively shortening the freeze-drying cycle has obvious economic value in industrial production.
Application areas
Food freeze dryers are widely used in freeze drying of various foods and snacks in major food factories.
