美国SP Virtis FTS Lyostar3 研发型冻干机

冻干机设备性能的测量：两种方法的比较

The objective of this investigation was to evaluate two methods for measuring the maximum sublimation rate that a freeze-dryer will support—the minimum controllable pressure method and the choke point method. Both methods gave equivalent results, but the minimum controllable pressure method is preferred, since it is easier, faster, and less subjective. The ratio of chamber pressure to condenser pressure corresponding to the onset of chokedflflow was considerably higher in this investigation (up to about 20:1) than in previously published reports. This ratio was not affected by the location of the pressure gauge on the condenser; that is, on the foreline of the vacuum pumpversuson the body of the condenser itself. The total water loss due to sublimation as measured by tunable diode laser absorption spectroscopy was consistently within 5% of gravimetrically determined weight loss, regardless of whether the measurement took place during chokedversusnon-choked process conditions.

Basic Principles Of Freeze-Drying

Freeze-drying is the removal of ice or other frozen solvents froma material through the process of sublimation and the removal ofbound water molecules through the process of desorption. Lyophilization and freeze-drying are terms that are usedinterchangeably depending on the industry and location wherethe drying is taking place. Controlled freeze-drying keeps the product temperature low enough during the process to avoidchanges in the dried product appearance and characteristics. It is an excellent method for preserving a wide variety of heat sensitive materials such as proteins, microbes, pharmaceuticals,tissues & plasma.