The difference between a small freeze dryer and a production freeze dryer
1. The difference in the basic performance of the device
The basic performance is mainly: shelf temperature performance (slab cooling rate, minimum temperature, heating rate, maximum temperature, control temperature of the board), condenser performance (water capture, minimum temperature, cooling system, condenser temperature control), Vacuum performance (pumping speed, ultimate vacuum, leak rate), vacuum control mode (throttling control, aeration control).
2.the difference in heat transfer
The sublimation heat of the pharmaceutical preparation is supplied by the heat transfer from the lower shelf surface to the bottom surface of the medicine bottle and the radiation heat transfer from the box wall surface and the upper shelf surface. The former is undoubtedly in a dominant position, but the latter is also a heat source. For example, in a case made of SUS, the medicine bottles are arranged on the shelf. When the plate temperature is -5°C, the drying speed of the outer medicine bottles is slower than that of the radiation heat. Increase by 30%.
Regarding the uniformity of the heat transfer of the slab layer, we are exploring measures such as increasing the flow rate of the heat transfer fluid in the shelf, improving the flow path, and improving the flatness of the bottom surface of the shelf, tray, and medicine bottle. On the other hand, the radiant heat transfer from the wall of the box is related to the following factors:
A. The emissivity of the shelf, the emissivity of the box wall [separator]
B. Radiation angle coefficient between shelf surface, cabinet wall and medicine
C. Box wall temperature
Therefore, the difference in heat transfer between the testing machine and the production device is shown in the following aspects:
A. The difference in the uniformity of the shelf temperature of each layer
B. Difference of shelf temperature control accuracy
C. The difference in radiant heat transmitted from the wall of the box to the medicine bottle
In particular, the radiant heat transmitted from the testing machine to the medicine bottle on the board is quite different from the production device.
