GFD Vacuum Freeze Dryer

Vacuum Freeze Dryer is an advanced Hi-Tech dehydration technology. It makes hydrous material frozen in the low temperature status, then under the vacuum condition, it adopts thermal radiation method for heating, to sublimate ice to gas directly. After the moisture comes out, it use ice-condenser ( cold trap ) and vacuum device to dehydrate the water content. It is a combined application technology based on multidisciplinary development, including refrigeration, heating, vacuum, biological, electrical and etc.

Equipment characteristics

GFD series vacuum freeze dryer mainly includes: material quick freezing system, vacuum tank system, heating system, vacuum system, refrigeration system, material transfer system, electric control system, pneumatic system, disinfection system.
The whole machine system is in optimized deployment, the whole design is reasonable, economic and advanced. The operation is high efficient, high degree of automatic, low engergy consumption, easy operation and convenient maintenance.
The vacuum system apply water ring pump or oil seal pump with multi-stage roots pump combination. In the beginning, it uses oil seal pump with large power to  remove air out quickly. And then, it uses roots pump to keep the vacuum condition with small power. In this way, it can decrease the energy consumption. Meanwhile, the water ring pump can remove the water content, which can avoid the disadvantage of oil seal pump of poor drainage performance, moisture making oil emulsfication metamorphism and vacuum instability.
Heating system is sealed water circulation system with automatic compression function. It applies 3-way regulated valve to adjust the heat of water circulation system. The automatic compression system can gurarantee hot water temperature to +120*C, which increase the thermal efficiency.
Refrigeration system applies Freon refrigeration for samll middle model. The expansion valve adjusts liquid flow automatically. For large model, it applies ammonia Single-phase circulation refrigeration, the refrigeration liquid supply is stable and easy for operation. The Ice-Condenser apply postposition type cold trap. The pipes connection is short, little resistance. Moisture and gas access is smooth. The water catch is evenly, efficient and engergy saving.
The electric control system applies intelligent instrument and PLC system. The PLC is with touch screen control, computer monitoring. Since the most important performance is the freeze drying curve control, we develop an automatic control system with 10 period of time controlling, which is specialized for food lyophilization. It make curve parameter setting more easily and convenient, high reliability, good accuracy. The system has the function of historical data storage and query, which is convenient for production process analysis.

Summary of vacuum freeze drying
Vacuum Freeze Drying is an advanced Hi-Tech dehydration technology. It makes hydrous material frozen in the low temperature status, then under the vacuum condition, it adopts thermal radition method for heating, to sublimate ice to gas directly. After the moisture comes out, it uses ice-condenser(cold trap) and vacuum device to dehydrate the water content. It is a combined application technology based on multidisciplinary development, including refrigeration, heating, vacuum, biological, electrical and etc.
Vacuum freeze drying technology has widely application, such as for chemical products, biologics, health product, herbs, agricultural products(meat, poultry, egg, sea food, vegetables and fruits and etc.).

Vacuum Freeze Drying Process
In principle, the vacuum freeze drying process includes three main stages:
1.First stage, the quick freezing. By freezing, the water content in the products turns into solid status from liquid status. In this step, the final frozen temperature should be below its eutectic point temperature(got by test), which guarantee the material is totally frozen. The material freezing speed depends on different material features. In this stage, it uses quick blast freezing room for pre-freezing.
2.Second stage is the primary dehydration stage, which is also called sublilmation dehydration stage. The frozen material with below eutectic point temperature will be dehydrated in vacuum condition, by sublimation method to remove its moisture. During sublimation, the heating plate temperature and vacuum condition should be controlled strictly, to prevent the material from melting or the temperature higher than eutectic point. Also it should prevent the dried parts temperature no higher its disintergration temperature which change the shape or even collapse. In this stage, the heating plates heat the material by thermal radiation, or provide the energy for sublimation. The vacuum tank must under vacuum condition. The ice-condenser(cold trap) will catch the moisture which comes from material, and condense to ice on the cold trap coils surface.
3.Third stage is the secondary dehydration stage. It is also called desorption drying. The purpose of this step is to remove bound moisture. Because of the adsorption energy of bound moisture is very large, it need to provide large heat energy in this stage, which means the heating plates temperature will be a little higher, to approach the highest temperature for material to bear. When the material moisture within specified data, the final dehydration is done.
 To decide whether the vacuum freeze drying is finished, it can depend on experience for material temperature curve, sample status, shape and etc. Also we can judge it by terminal point testing(air pressure increase).

Equiment Features
GFD Series vacuum freeze dryer mainly includes: material quick freezing syatem, vacuum tank system, heating system, vacuum system, refrigeration system, material transfer system, electric control system, pneumatic system, disinfection system.
1.The whole machine system is in optimized deployment, the whole design is reasonable, economic and advanced. The operation is high efficient, high degree of automation, low energy consumption, easy operation and convenient maintenance.
2.The vacuum system apply water ring pump or oil seal pump with multi-stage roots pump combination. In the beginning, it uses oil seal pump with large power to remove air out quickly. And then, it uses roots pump to keep the vacuum condition with small power. In this way, it can decrease the energy consumption. Meanwhile, the water ring pump can remove the water content, which can avoid the disadvantege of oil seal pump of poor drainage performance, moisture making oil emulsification metamorphism and vacuum instability.
3.Heating system is sealed water circulation system with automatic compression function. It applies 3-way regulated valve to adjust the heat of water circulation system. The automatic compression system can guarantee hot water temperature to +120℃, which increase the thermal efficiency.
4.Refrigeration system applies Freon refrigeration for small-middle models. The expansion valve adjusts liquid flow automatically. For large model, it applies ammonia Single-phase circulation refrigeration; the refrigeration liquid supply is stable and easy for operation. The ice-condenser apply postposition type cold trap. The pipes connection is short, little resistance. Moisture and gas access is smooth. The water catch is evenly, efficient and energy saving.
5.The electric control system applies intelligent instrument and PLC system. The PLC is with touch screen control, computer monitoring. Since the most important performance is the freeze drying curve control, we develop an automatic control system with 10 period of time controlling, which is specialized for food lyophilization. It makes curve parameter setting more easily and convenient, high reliability, good accuracy. The system has the function of historical data storage and query, which is convenient for production process analysis.

Vacuum Freeze Dryer technology has widely application, such as for chemical products, biologics, health product, herbs, agricultural products ( meat, poulty, egg, sea food, vegetables and fruits etc. ).

Technical description:
1.There are rear-mounted, side-mounted, top-mounted as cold trap position of GFD series freeze dryer;
2.There are different defrosting methods, including one-time water defrosting, steam defrosting and automatic alternated defrosting.
3.There are different size freeze dryer according to the capacity, such as minitype lab freeze dryer, middle-size production type, large-size production type, except the size in the table, others size can be customized.
4.GFD series freeze dryer adopt two ways heating, one heating way by electric for minitype and middle-size freeze dryer, other heating way by steam for large-size freeze dryer.
5.GFD series freeze dryer adopt Freon and Ammonia for the refrigeration system. It is Freon refrigeration system parameters in the table.
6.Advise minimum usable area included: equipment floor area, equipment maintenance space, processing materials flow area. Multiple sets of  equipment can save equipment usage space, according to the actual matching design.

Advantages of vacuum freeze drying technology:
Comparing with normal sun drying, hot air dryig, spray drying and vacuum drying, there are several outstanding advantages of vacuum freeze drying:
a.Vacuum freeze drying is dehydration process in low temperature, which will not damage protein. While it will make the microorganism losing vitality.
b.For the same reason, it makes little loss of volatility content, nutrition, aromatic and flavor in the material.
c.During the low temperature dehydration, microorganism’s growing and enzyme almost cannot work, which keeps material original features.
d.After dehydration, the material volume, shape will not change. The final product is in cavernous status, no shrinkage. When rehydration, because of the efficient contacting area is large, it will regain the original shape quickly.
e.In vacuum condition for dehydration, there is very little oxygen content, which will protect the oxidized material.
f.Vacuum freeze drying can remove 95%~99.5% of the moisture from the material, which brings the final product with long shelf life.