Shanghai Haozhuang Instrument Co., Ltd. has developed the LNB brand freeze dryer, which is energy-saving and environmentally friendly, leading the country. Professional manufacturing is more secure and affordable.

Several parameters that should be paid attention to when purchasing freeze dryer

1. Freeze-dried area

The number in the freeze dryer model represents the freeze drying area of ​​the freeze dryer. For example, the freeze drying area of ​​the LGJ-18C freeze dryer is 0.18㎡. Users should determine how much freeze-drying area to use according to their own needs. For example, for each batch of products that require lyophilization of 1.8 kg (liter) of liquid, use the material tray to load the material, each tray is loaded with 10㎜ thick, then the load area of ​​the freeze-dried board layer can be calculated:

A (Area, ㎡) = V (Volume, m) / H (Height, m) = 0.0018m / 0.01m = 0.18㎡

That is, a freeze dryer with a load area of ​​0.18 square meters should be selected.

2. Cold trap temperature

The cold trap is a device for capturing moisture in the freeze-drying process. In theory, the lower the temperature of the cold trap, the stronger the water trapping ability of the cold trap, but the lower the temperature of the cold trap, the higher the refrigeration requirements, the higher the machine cost and operating cost. The temperature of the cold trap of the experimental series freeze dryer mainly has several grades such as about -45 ℃, about -60 ℃, and about -80 ℃. Freeze-drying with a cold trap temperature of -45 ° C is suitable for some products that are easy to freeze-dry. Freeze-dryers with a cold trap temperature of about -60 ° C are suitable for freeze-drying of most products. Freeze-drying with a cold trap temperature of -80 ° C It is suitable for lyophilization of some special products. The experiment of the influence of the cold trap temperature on the water-capturing ability shows that the temperature of the cold trap decreases from -35 ℃ to -55 ℃, and the water-capturing ability is obviously improved. Therefore, in the absence of special requirements, it is ideal to choose a cold trap temperature around -60 ℃. In the four-ring freeze dryer, the cold trap temperature of LGJ-10D freeze dryer is ≤-55 ℃, the cold trap temperature of LGJ-18 series and LGJ-25 series freeze dryer is ≤-60 ℃, and mixed refrigerant is used for refrigeration 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-ring freeze dryer also includes a LGJ-10 freeze dryer with a cold trap temperature ≤-45 ° C, which is suitable for the freeze-drying of some products that are easy to freeze-dry. The cold trap temperature of LGJ-50C freeze dryer is ≤-80 ℃, especially suitable for freeze drying of medicine and special products.

3. Cooling rate

The cooling rate reflects the cooling capacity of the refrigeration system. Under no-load conditions, the cold trap temperature should reach the minimum temperature specified in the index within 1 hour. For example, for a freeze dryer with a cold trap temperature ≤-60 ° C, the machine will start timing when the refrigeration is turned on, and the time for the cold trap temperature to reach -60 ° C shall not exceed 1 hour.

4. Ultimate vacuum

The ultimate vacuum degree reflects the leakage of the freeze dryer and the pumping efficiency of the vacuum pump. The vacuum degree of the freeze-drying box, the past view that the higher the vacuum degree, the better, the industry view that the vacuum degree should be within a reasonable range. The vacuum is too high, which is not conducive to heat transfer, but the drying speed is reduced, but in any case, the empty vacuum limit of the freeze-drying box should reach more than 15Pa.

5. Vacuum time

The evacuation speed of the freeze-dried box with no load should be evacuated from atmospheric pressure to 15Pa within half an hour.

6. Layer temperature uniformity and flatness:

The uniformity and flatness of the ply temperature have a great influence on the uniformity of product quality. The better the temperature uniformity and flatness, the better the uniformity of the quality of the freeze-dried product. The temperature control of the shelf of the freeze dryer includes heater type and intermediate fluid type. The temperature uniformity and flatness of the shelf of the freeze dryer using the intermediate fluid control layer are good. The cooling and heating are achieved through the circulation of the intermediate fluid in the fluid channel inside the layer, so the temperature of the layer is uniform. In the four-ring freeze dryer, the LGJ-50C freeze dryer adopts the technology of intermediate fluid in the shelf. The temperature control of the shelf of the bell-type freeze dryer is basically a heater, and the temperature consistency of the layer is slightly worse. But generally speaking, the temperature difference of the medicine freeze dryer should be controlled within ± 1.5 ℃, and the temperature difference within the plate should be ± l ℃, and the food freeze dryer can be relaxed appropriately.

7. Control system

The type and function of the control system of the freeze dryer are different. For the experimental series of freeze dryer, it is mainly used for exploring the freeze-drying process of materials and a small amount of trial production. Therefore, the control system should be able to display and automatically record the parameters of the freeze-drying process in real time; set, modify and effectively execute the freeze-drying process program; have a communication interface to facilitate data collection and storage.

Strive to make the products beautiful, practical, stable and cost-effective, and strive to save more experimental space for our customers. Shanghai Haozhuang will provide you with safe, stable and high-performance experimental equipment as always, making your experimental process more even Easy.

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