Verifying shelf temperature uniformity is a very important part of lyophilizer equipment verification. The uneven temperature of the freeze-drying machine shelf directly affects the uniformity of the product during the freeze-drying process. If the temperature is uneven, the freezing rate of the medicine may be inconsistent during the freezing process, or some medicines may not be frozen solid: the same will occur in the drying stage. The drying rate of medicines is inconsistent, and the temperature of some medicines may even exceed the eutectic temperature and freeze-drying fails. Therefore, the temperature uniformity of each point between the same shelf and the temperature uniformity of each point between different shelves are particularly important.
Check and confirm that under the set temperature, the electric heating system and the refrigeration system can ensure that the temperature of the board layer varies within the allowable fluctuation range and that the uniformity of the temperature distribution of the board layer when the vacuum freeze dryer is running at no load meets the design requirements, and the temperature control capability meets the design requirements. and requirements.
Method: Put the temperature measuring resistance of the temperature detector into the freeze-drying box through the verification hole of the freeze-drying machine; evenly distribute 36 numbered thermocouple probes on the 10 layers of the freeze-drying machine. The layers were fully contacted; the freeze dryer was started, and the temperature distribution test was carried out under a no-load state. The temperature test points were -40 °C, 0 °C, and 40 °C, respectively, and the test data were recorded when the temperature was constant for 30 min. After the results reached the temperature, during the temperature maintenance process, the maximum and minimum temperature differences of all test points on each plate layer of the freeze dryer at the same time were less than 2 °C.
