Depending on the specific sample, there are different options for lyophilization. Common laboratory freeze-drying experiments are carried out by the rocess B method. j is freeze-dried in the freeze-drying chamber or hanged in a bottle. If it is freeze-dried in the freeze-drying chamber, j needs to be purchased and freeze-dried. To choose the capping device; if the bottle is freeze-dried, you must choose a multi-manifold, suitable for round flasks, wide-mouth filter bottles or ampoules, but pay attention to whether you need to choose the appropriate adapter to use in combination; The samples involved include both freeze-drying in the cavity and freeze-drying in the bottle.
How to choose a freeze dryer?
1. Freeze-dried area
The number in the freeze model represents the freeze-drying area of the freeze dryer. For example, the freeze-drying area of the ZX-type freeze dryer is .㎡. The user should calculate according to his own needs, how much freeze-drying area the freeze dryer needs. For example, for each batch of products that need to be lyophilized. kg (liter) of liquid, use the material tray to load the material, and each tray is loaded with a thickness, then the load area of the freeze-dried board layer can be calculated: A (area, ㎡) = V (volume ,M)/H(gd,m)=.m/.m=.㎡j Freeze dryer with a layer load area of .㎡ is required.
2. Temperature rate
The temperature rate reflects the cooling capacity of the refrigeration system. Under no-load conditions, the temperature of the cold trap should reach the low temperature specified by the index within hours. For example, for a freeze dryer with a cold trap temperature of ≤-℃, the machine will start timing when the refrigeration is turned on, and the time for the cold trap temperature to reach -℃ shall not be greater than hours.
3. Vacuum
The degree of vacuum reflects the leakage of the freeze dryer and the pumping efficiency of the vacuum pump. In the past, the vacuum degree of the freeze-drying box was considered to be as high as possible. The current view is that the vacuum degree should be within a reasonable range. The vacuum degree is too high, which is not conducive to heat transfer, but the drying speed is down, but in any case, the empty vacuum level of the freeze-drying box should reach Pa or less. Vacuum time The evacuation speed of the freeze-dried box without load should be pumped to Pa within half an hour. Layer temperature uniformity and flatness: the layer temperature uniformity and flatness have a great influence on the product quality uniformity, the better the temperature uniformity and flatness, the more the freeze-dried product quality uniformity it is good. 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 layer of this freeze dryer is a hollow sandwich structure. The cooling and heating of the intermediate fluid is realized in the fluid channel in the inner part of the layer, so the temperature of the layer is uniform.