Vacuum freeze dryer for high-end raw materials, Chinese medicine Pieces, seafood, wild vegetables, dehydrated vegetables, food, fruit, chemical intermediates and other materials dry.
Vacuum freeze-drying machine will be refrigeration system, vacuum system, thermal oil heating system, a combination of dehumidification system, a new type of box structure, the larger use of storage materials within the box space for drying vacuum drying, drying powder Have a good dispersion.
Frozen vacuum drying process is free of impurities into the object, to maintain the original ingredients and active ingredients and material body is not damaged.
After the start of the material into the material box to freeze the material of the freezing process, on the one hand is a vacuum system to vacuum part of the water away; the other hand, when the material is frozen when the water contained in some molecules The surface of the material is frozen, and after the freezing requirements are reached, the material is heated and dried by the heating system. The moisture contained in the material is brought to the freezing collection tank by vacuuming to meet the requirements of freeze drying.
Frozen drying refers to the process by which sublimation removes water or other solvents from frozen biological products. Sublimation refers to the solvent, such as water, like dry ice, without liquid, from solid to direct into the process of gaseous. The product obtained by freeze drying is called lyophilizer, which is called lyophilisation. Traditional dryness can cause the material to shrink and destroy the cells. The structure of the sample during the freeze-drying process will not be destroyed because the solid component is supported by ice in its position. In the ice sublimation, it leaves the pores in the dry residue. This preserves the integrity of the biological and chemical structure of the product and its activity. In the laboratory, freeze-dried has many different uses, it is in many biochemical and pharmaceutical applications is indispensable. It is used to obtain long-term preservation of biological materials, such as microbial culture, enzymes, blood, and drugs, in addition to long-term preservation of stability, but also retains its inherent biological activity and structure. For this reason, lyophilization is used to prepare tissue samples for structural studies (eg, electron microscopy). Freeze-drying is also used in chemical analysis to obtain a dry sample or to concentrate the sample to increase the analytical sensitivity. Freeze-dried so that the sample composition is stable, do not need to change the chemical composition, is the ideal analysis of auxiliary means. Freeze-drying can occur naturally. In the natural case, this process is slow and unpredictable. Through the freeze-drying system, people improved, subdivided a lot of steps to speed up the process.
From the structure points
Bell-type freeze-drying machine: freeze-drying chamber and cold trap for the vertical structure of the upper and lower, freeze-drying chamber without pre-freeze function. The type of freeze dryer in the material after the end of pre-freeze into the drying process requires manual operation. Most of the experimental freeze-drying machines are bell-type, its structure is simple, low cost. Most of the freeze-drying chamber using transparent plexiglass cover, easy to observe the freeze-dried materials. 
In situ freeze-drying machine: freeze-drying chamber and cold trap for two separate cavity, freeze-drying chamber with cooling function, the material into the freeze-drying chamber, the material pre-freeze, drying process without manual operation The This type of freeze-drying machine has a complicated manufacturing process and high manufacturing cost. However, the in-situ freeze-drying machine is the ideal choice for the freeze-drying process. It is especially suitable for pharmaceutical, biological products and other special products. Lyophilized.
A, ordinary type b, multi-manifold type c, gland type
From the function points
Ordinary shelf type: material in bulk material, suitable for food, Chinese herbal medicine, powdery materials freeze-dried.
With gland device type: suitable for Xilin bottled material drying, freeze-dried preparation, according to the need to separate the material in the vials, floating cover a good bottle after the freeze-drying, dry after the operation of gland press the bottle , To avoid secondary pollution, re-adsorption of water, easy to long-term preservation.
Multi-manifold type: in the drying room outside the flask, the frozen in the bottle wall of the material drying, then the flask as a container connected to the manifold outside the tank, the flask material heated by room temperature, through the differences Tube switch device, can be removed at any time or installed on the flask, do not need to stop.
With pre-frozen functional type: material pre-freezing process, cold trap as a pre-frozen pre-frozen material, in the drying process, cold trap for the catcher, to capture the material overflow of water. Pre-freeze function with freeze-drying machine, freeze-drying process of pre-freezing, drying, etc. are completed in the freeze dryer, freeze-drying machine using high efficiency, saving the cost of low-temperature refrigerator.
Choose a few freeze-drying machine should pay attention to the parameters
Freeze dry area
The number in the freeze-drying machine model represents the freeze-dried area of ??the freeze-drying machine. For example, the freeze-drying area of ??the LGJ-18C type freeze-drying machine is 0.18㎡. Users should be based on their own needs, through the calculation to determine how much need to freeze the dry area of ??the freeze dryer. For example, each batch of freeze-dried 1.8 kg (l) liquid volume of the product, with the material tray loading materials, each loaded 10 mm thick, you can calculate the dry layer of dry weight:
A (area, ㎡) = V (volume, m) / H (height, m) = 0.0018m / 0.01m = 0.18㎡
That is required to use the board load area of ??0.18 square meters of freeze dryer.
Cold trap temperature
In theoretically, the lower the cold trap temperature, the higher the trap capacity of the cold trap, but the cold trap temperature is low, the refrigeration requirements are high, the machine cost and running cost are high. Experimental series of freeze-drying machine cold trap temperature is mainly around -45 ℃, -60 ℃ or so, -80 ℃ and so on several grades. Freeze temperature of -45 ℃ freeze-dried for some easy to freeze-dried products, cold trap temperature of about -60 ℃ freeze dryer for most of the products freeze-dried, cold trap temperature of -80 ℃ freeze-dried Suitable for freeze-drying of some special products. The effect of cold trap temperature on catching capacity shows that the temperature of cold trap decreases from -35 ℃ to -55 ℃, and the catching ability is improved obviously. The cold trap temperature is lower than -55 ℃, and the catching ability of cold trap is not obvious. Therefore, in the absence of special needs, the choice of cold trap temperature around -60 ℃ is the ideal choice. The cold trap temperature of LGJ-10D freeze-drying machine in the four-ring freeze-drying machine is ≤-55 ℃, the freezing temperature of LGJ-18 series and LGJ-25 series is less than -60 ℃, and the refrigerant is cooled by mixed refrigerant Technology, in the case of the same refrigeration unit, the cooling temperature is low, the cooling capacity is large, the working stability is high and the failure rate is low. The four-cycle freeze-drying machine also includes a LGJ-10 freeze dryer with a cold trap temperature of ≤ -45 ° C for lyophilisation of products that are easily lyophilized. LGJ-50C freeze-drying machine cold trap temperature ≤ -80 ℃, especially for pharmaceutical and special products freeze-dried. 
3, the cooling rate
Cooling rate reflects the refrigeration system cooling capacity, in the case of no-load, the cold trap temperature should be within 1 hour to reach the minimum temperature specified by the target. For example, a chiller with a cold trap temperature of ≤-60 ° C, the machine should start from the beginning of the cooling and the time when the cold trap temperature reaches -60 ° C should be no more than 1 hour.
4, the ultimate degree of vacuum
The ultimate vacuum reflects the leakage of the freeze dryer and the evacuation efficiency of the vacuum pump. The vacuum of the freeze box, the past view that the vacuum is the higher the better, the industry’s view that the vacuum should be within a reasonable range. Vacuum is too high, is not conducive to heat transfer, drying speed but decreased, but in any case freeze-drying box vacuum limit should be more than 15Pa vacuum.
5, the vacuum time
The temperature of the freezers in the freezer should be drawn from the atmospheric pressure to 15 Pa within half an hour.
6, the board temperature uniformity and flatness:
The uniformity and flatness of the slab temperature have a great influence on the homogeneity of the product quality. The better the temperature uniformity and the flatness, the better the uniformity of the dry product quality. Freeze-drying shelf shelf temperature control of the heater type and the middle fluid type, the use of intermediate fluid control plate layer freeze-drying machine shelf temperature uniformity and smoothness, and this freeze-drying machine board for the hollow sandwich structure, Of the cooling and heating through the intermediate fluid in the plate inside the fluid channel to achieve, so the board temperature uniformity. Four-stage freeze-drying machine LGJ-50C type freeze dryer on the use of shelf intermediate fluid technology. Bell-type freeze-drying machine shelf temperature control are basically using the heater, board temperature consistency is slightly worse. But in general, the temperature difference between the medicine should be controlled at ± 1.5 ℃, the temperature difference between the plate is ± 1 ℃, the food freeze dryer can be relaxed.
7, the control system
Freeze-drying machine control system types and functions vary, for the experimental series of freeze-drying machine, mainly used in the material freeze-drying process to explore and a small amount of trial production. Therefore, the control system should be able to display the freeze-drying process parameters in real time and automatically record; set, modify and effectively carry out freeze-drying process; with communication interface for easy data collection and preservation.