Lyophilization Technology of Vacuum Freeze Dryer

Lyophilization of a Vacuum Freeze Dryer was used to prepare tissue samples for structural studies (eg, electron microscopy studies). Freeze drying is also used in chemical analysis to obtain dried samples or to concentrate samples to increase analytical sensitivity. Freeze-drying stabilizes the sample components without changing the chemical composition, making it an ideal analytical aid. Freeze drying can occur naturally. In the natural case, this process is slow and unpredictable. Through the freeze-drying system, people have improved and subdivided many steps to speed up the process.

Bell-type Vacuum Freeze Dry Machine: The freeze-drying chamber and the cold trap are upper and lower structures, and the freeze-drying chamber has no pre-freezing function. This type of lyophilizer requires manual operation when it is transferred to the drying process after the material has been pre-frozen. Most of the experimental Freeze Dry Machine are bell-type, with a simple structure and low cost. Most of the freeze-drying chambers use a transparent plexiglass cover to facilitate the observation of the lyophilization of the material.

In-situ freeze-drying machine vacuum freeze-drying machine: the freeze-drying chamber and the cold trap are two independent chambers, and the shelf in the freeze-drying chamber has a cooling function. After the material is placed in the freeze-drying chamber, the material is pre-frozen and dried. The process does not require manual operation. This type of freeze dryer has a complicated manufacturing process and high manufacturing cost, but the in-situ freeze dryer is the development direction of the freeze dryer, an ideal choice for lyophilization process, especially suitable for medicine, biological products and other special products.

Ordinary shelf type vacuum freeze-drying machine: The material is bulk-packed in the material tray and is suitable for lyophilization of food, Chinese herbal medicine and powder materials.

Vacuum lyophilizer with gland type device: suitable for drying of bottled materials in Xilin. When lyophilized, prepare the materials in the vials as needed, float and cover the caps, freeze-dry them, and operate the gland mechanism after drying. The bottle cap can be pressed to avoid secondary pollution, re-adsorb moisture, and easy to store for a long time.

Principle and Structure of Vacuum Freeze Dryer

The food vacuum Freeze Dry Machine not only maintains the freshness and nutrition of the food, but also prolongs the shelf life of the food. What is the principle and composition of the Vacuum Freeze Dryer ?
The vacuum Freeze Dry Machine is a drying technique in which a wet material or a solution is frozen to a solid state at a lower temperature and then the water therein is directly sublimated into a gaseous state without being liquid, and finally the material is dehydrated.

The Principle of Food Vacuum Freeze Dryer principle

The constant supply of heat and the continuous elimination of steam generation. In the initial stage, if the material temperature is relatively high, the latent heat required for sublimation can be taken from the sensible heat of the material itself. However, as the sublimation progresses, the temperature of the material quickly drops to a temperature equilibrium with the vapor partial pressure of the drying chamber. At this time, if there is no external heating, the sublimation drying stops. In the case of external heating, if the steam generated by sublimation is not eliminated in time, the partial pressure of steam will increase and the temperature of the material will increase. When the material freezes, the ice crystals in the material will melt. Freeze drying will not work.

The structure of Food Vacuum Freeze Dry Machine

(1) The drying box has two main forms of cylindrical and square, each having advantages. The cylindrical shape is easy to manufacture, but the space that cannot be utilized is large; the square is opposite, the space utilization rate is high, but manufacturing is difficult.

(2) Most of the heating system uses radiation heat transfer. The radiant panel is made of anodized aluminum. The heat transfer medium has heat transfer oil, saturated water, secondary steam, organic solvents such as propylene glycol, glycerin, etc. The heat source is high pressure water vapor.

(3) The vacuum system adopts mechanical vacuum pump, including Roots pump + oil seal pump and Roots pump + Roots pump + atmospheric injection + water ring pump. More information click gf-machine

Operation Process of Freeze Dry Machine

The amount of water vapor in the compressed air is determined by the temperature of the compressed air: Reducing the temperature of the compressed air reduces the amount of water vapor in the compressed air while maintaining the constant pressure of the compressed air, and the excess water vapor condenses into a liquid.Freeze Dry Machine uses this principle with refrigeration technology to dry compressed air. Therefore, the Freeze Dry Machine has a refrigeration system.

The refrigeration system of the Freeze Dry Machine is a compression type refrigeration system consisting of four basic components: a refrigeration compressor, a condenser, an evaporator, and an expansion valve. They are connected by a pipe connection to form a closed system in which the refrigerant circulates continuously in the system, undergoes a state change and exchanges heat with the compressed air and the cooling medium.

The refrigeration compressor draws the low-pressure (low-temperature) refrigerant in the evaporator into the cylinder of the compressor, and the refrigerant vapor is compressed, and the pressure and temperature are simultaneously increased; the high-pressure high-temperature refrigerant vapor is pressed to the condenser, and in the condenser, The higher temperature refrigerant vapor exchanges heat with the cooler water or air, and the heat of the refrigerant is taken away by water or air to condense, and the refrigerant vapor becomes a liquid.

This part of the liquid is then sent to the expansion valve, which is throttled into a low-temperature and low-pressure liquid through the expansion valve and enters the evaporator; in the evaporator, the low-temperature, low-pressure refrigerant liquid absorbs the heat of the compressed air and vaporizes (commonly called „evaporation”) The compressed air is cooled to condense a large amount of liquid water; the refrigerant vapor in the evaporator is sucked away by the compressor, so that the refrigerant undergoes four processes of compression, condensation, throttling, and evaporation in the system, thereby Completed a loop.

In the refrigeration system of the Freeze Dry Machine, the evaporator is a device for conveying a cold amount, in which the refrigerant absorbs the heat of the compressed air to achieve the purpose of dehydration and drying. The compressor is the heart and acts to draw, compress, and deliver refrigerant vapor.
GuanFeng supplies different kinds of freeze drying machines. High quality and favorable price. We′re pleased to get your Inquiry and we will come back to as soon as possible. If you interested in our products, please feel free to contact us any time:

Zhejiang Guanfeng Food Machinery Co.,Ltd.

Add : South industrial park of Dongguan, Shangyu District, Shaoxing City, Zhejiang Province, China 312352

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Vacuum And Hydraulic System of GF Lyophilization Equipment

The moisture in the product can be sublimated quickly only under vacuum to achieve the purpose of drying. The vacuum system of Lyophilization Equipment consists of a freeze-drying box, a condenser, a vacuum valve, a vacuum pump, a vacuum line, and a vacuum measuring component.

The system of Lyophilization Equipment uses a vacuum pump set to form a powerful suction capacity, forming a vacuum in the drying chamber and the condenser, on the one hand, causing the water in the drying chamber to evaporate under vacuum. The vacuum degree of the vacuum system should match the sublimation temperature of the product and the temperature of the condenser. If the degree of vacuum is too high or too low, it is not conducive to sublimation. The vacuum degree of the drying box should be controlled within the set range. Shortening the sublimation cycle of the product, the premise of vacuum control is that the vacuum system itself must have a small leakage rate. The vacuum pump has a large enough power reserve to ensure that the ultimate vacuum is reached.

The hydraulic system of Lyophilization Equipment is a special device that presses the stopper into the bottle mouth at the end of freeze drying. The hydraulic system is located at the top of the drying box and is mainly composed of an electric motor, an oil pump, a check valve, a relief valve, a solenoid valve, a fuel tank, a cylinder and a pipe.

At the end of Lyophilization, the hydraulic plugging system starts to work, and under vacuum conditions, the upper shelf is slowly moved downward to complete the product bottle stoppering task. The hydraulic oil pump station, oil cylinder, etc. are installed in the top of the freeze-drying tank. Under the drive of the hydraulic pump station, the plate layer is lifted up and down in the tank to facilitate the entry and exit of the tank and the cleaning work.

The seal of the lower part of the piston rod of the cylinder uses O-type silicon. The rubber seal ensures that oil will not be contaminated and the drug will be contaminated. The piston uses a YX polyurethane seal. The electromagnetic reversing valve and the hydraulic balancing valve are accurate in signal transmission, and do not slip without vibration. Click gf-machine for in-depth information about GF Machinery.

Drying Box of GF Lyophilization Equipment

The drying oven is one of the important components in the Lyophilization Equipment, and its performance directly affects the performance of the entire Lyophilization Equipment. The freeze-drying box of Lyophilization Equipment is a rectangular or drum type, which can be cooled to about -40C. It can be heated to a vacuum-sealed high and low temperature box body of about +50C.

The bottom of the cabinet is slightly inclined to the rear, and the drain is designed at the lowest point to facilitate drainage.

The freeze-drying of the product is carried out in a dry box, in which there is mainly a shelf on which the product is placed.

The shelves are made of stainless steel with media ducts distributed inside to cool or heat the product.

The laminar components are installed in the freeze-drying box through the bracket, and are driven by the hydraulic piston rod to move up and down, which is convenient for feeding and discharging and cleaning.

The uppermost layer is a temperature-compensated stiffener that ensures the same thermal environment for all products in the box.

The freeze-drying box of Lyophilization Equipment can be installed with the wall of the sterile room. The door is sealed with a special shape silicone rubber strip to seal the door to the same finish as the inside of the freeze-drying box. The material of the door is also made of high-quality stainless steel. It has the same smoothness and flatness as the inside of the freeze-drying box. It can be closely attached to the sealing strip to ensure the sealing under vacuum. The opening angle of the box door of the freeze-drying box is >110 degrees, and the observation window is installed in the center of the door to facilitate the observation of the state of the product in the sterile room.

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Refrigeration System of Lyophilization Equipment

Refrigerant is the working medium in the refrigeration system of Lyophilization Equipment , which is a special kind of liquid with low boiling point, so it is easy to evaporate at low temperature, when it absorbs the surrounding heat during evaporation, the temperature of surrounding objects is lowered Then, the vapor of the liquid is compressed into a high-temperature, high-pressure vapor, which is cooled in the condenser to become a liquid, and then the liquid is depressurized and throttled to absorb heat in the evaporator, so that the temperature of the evaporation portion can be made. Continuously reducing the refrigerant moves the heat from one object to another to achieve a cooling process.

The nature of the refrigerant is directly related to the refrigeration effect, economy, safety and operation management of the refrigeration unit. Therefore, the understanding of the refrigerant property requirements cannot be ignored. For the normal operation of the refrigeration system and to improve efficiency, the following requirements are imposed on the refrigerant of lyophilization equipment:

1.High critical temperature and a low condensing pressure;

2. The latent heat of vaporization and thermal conductivity of the liquid should be large. The specific volume of steam should be small.

3. The boiling point and freezing point are low

4. Density and viscosity, and the adiabatic index should be small.

5. Strong chemical stability, no chemical reaction with lubricant, no corrosive effect on machinery.

6. Harmless to the human body, non-flammable and explosive

7. Low price

Commonly used refrigerants include: ammonia (R717, Freon 12 (R12, Freon 13 (R13, Freon 22 (R22, azeotropic refrigerant R500, azeotropic refrigerant R502, azeotropic refrigerant R503, etc.).

In addition, the brine is an intermediate medium in the Lyophilization Equipment, also known as the second refrigerant, which is mainly used for cooling and heating the shelf in the tank, and transmits the absorbed heat to the refrigerant or absorbs the heat source. The heat is transferred to the shelf to provide the amount of cooling required to freeze the product and the sublimation heat of the product to dry. The purpose of using the brine is to make the shelf temperature uniform.

Zhejiang Guanfeng Food Machinery Co.,Ltd. specializes in lyophilization equipment and
Drying Equipment , If you interested in GuanFeng Machinery, e will spare no effort to provide professional consulting services and solutions to solve user problems. Welcome to consult and purchase our products and services. Contact us

Company: Zhejiang Guanfeng Food Machinery Co.,Ltd.

Add : South industrial park of Dongguan, Shangyu District, Shaoxing City, Zhejiang Province, China 312352

Lyophilization Equipment :

3 Factor of IQF Freezing Technology

First, the effect of cooling medium temperature. Under the process conditions of IQF Freezing Machine , the lower the temperature of the cooling medium, the faster the product freezes under the same conditions. At present, according to the specific situation in China, most of the ammonia is used as a refrigerant, and the evaporation temperature is generally selected between -35 and -45 °C. Under the IQF process, if a forced air continuous freeze is used, the temperature of the cooling medium is also related to the frosting speed of the evaporator. That is, when the evaporating frost layer reaches a certain thickness, the temperature of the cooling medium is correspondingly increased due to a decrease in the heat transfer effect. Therefore, in order to ensure the quality of the frozen, it should be done in time to defrost.

Second, the effect of air flow rate

Under the IQF Freezing process, the air flow rate is the main factor affecting the value of the exothermic coefficient. Therefore, an appropriate increase in the air flow rate can increase the degree of freezing end. For example, the common green beans freeze in the static air of -30°C, which takes about 2 hours. At the same temperature, the air flow rate increases to 4.5-5 m/s, and the freezing time is only 10 minutes.

Under certain conditions, the change between the freezing speed and the air flow rate is not linear, so the air flow rate should be comprehensively determined from an economic point of view.

Third, the effect of freezing termination temperature

The freezing termination temperature is lower than the storage temperature (-18 ° C), which is beneficial to maintain the structure under rapid freezing. If the freezing termination temperature is higher than -18 °C, the unfrozen water inside the vegetable tissue will generate large ice crystals, which will result in the destruction of the tissue structure and the increase of juice loss during thawing, which will affect the nutritional value and flavor of the product. If you are interested in learning more about freezing IQF, please click gf-machine