冻干过程中升华界面温度测量方法的研究

压力测温技术是基于在平衡状态下,冰晶温度与其饱和蒸汽压为单值函数这一基本规律,在升华干燥过程中,突然中断从冻干室流向冷阱的水蒸汽流,通过测量冻干室内压力回升情况去推算升华界面温度的一种非接触式测温方法。与热电偶或热敏电阻测温相比,压力测温技术即不破坏冻干样品的结构,又能够较为准确地反应出移动升华界面的温度,并能判断升华干燥过程终点。文中分析了升华界面温度测量的意义与困难,建立了压力测温技术的数学模型与分析方法,并通过实验研究了压力测温技术。

STUDY ON THE MEASUREMENT OF THE PRODUCT TEMPERATURE AT THE MOVING SUBLIMATION INTERFACE DURING THE FREEZE DRYING PROCESS

Barometric temperature measurement is a non-invasive method to measure the product temperature at the moving sublimation interface by analysis of the chamber transient pressure response after the flow of water vapor is interrupted from the product chamber to the cooling trap. Comparing to the other temperature measurements such as thermocouples and resistance temperature detectors, Barometric temperature measurement not only can measure the interface temperature with no influence to the sample texture, but also can determine the end of the primary drying stage. In this paper, the importance and the difficulties to measure the interface temperature are discussed, the mathematical model and the data regression method of the transient pressure response are introduced, and some experiments are carried on.