Purchasing Factors of Freeze Dry Machine I I Cooling ra […]
Purchasing Factors of Freeze Dry Machine I I
The cooling rate reflects the cooling capacity of the refrigeration system. Under no-load conditions, the temperature of the cold trap should reach the minimum temperature specified in the index within one hour. For example, a freeze dry machine with a cold trap temperature ≤ -60 ° C, the machine starts from the time of opening the refrigeration, and the temperature of the cold trap reaches -60 ° C should be no more than 1 hour.
The ultimate vacuum reflects the leakage of the freeze dry machine and the pumping efficiency of the vacuum pump. The degree of vacuum of the freeze-drying box, the past view that the higher the degree of vacuum, the better, the industry's view that the degree of vacuum should be within a reasonable range. The degree of vacuum is too high, which is not conducive to heat transfer, but the drying speed is reduced, but the vacuum limit of the freeze-drying box should reach 15Pa or more.
The emptying speed of the freeze-drying box should be pumped from atmospheric pressure to 15Pa within half an hour.
Layer temperature uniformity and flatness:
The uniformity and flatness of the lamellar temperature have a great influence on the uniformity of product quality. The better the temperature uniformity and the flatness, the better the uniformity of the quality of the freeze-dried product. The freeze dry machine shelf temperature control has a heater type and an intermediate fluid type, and the freeze-drying machine shelf with the intermediate fluid control plate layer has uniform temperature uniformity and flatness, and the lyophilizer layer is a hollow sandwich structure, the slab layer The cooling and heating are achieved by circulating the intermediate fluid in the fluid channel inside the ply, so the ply temperature is uniform. The LGJ-50C freeze dryer in the four-ring freeze dryer uses the technology of the intermediate fluid in the shelf. The shelf temperature control of the bell-type freeze dry machine is basically a heater, and the temperature uniformity of the layer is slightly poor. However, in general, the temperature difference of the freeze dry machine for medical use should be controlled at ±1.5 °C, the temperature difference within the plate is ±1 °C, and the food freeze dry machine can be appropriately relaxed.