| 摘要 |
<p>A method of and apparatus for vacuum drying a system. wherein the system is evacuated to effect vapourisation of a liquid therein and facilitate its removal from the system, with at least one sample of the liquid being positioned within the system. The temperatures of each sample and of the free space thereabove are monitored and the system is evacuated at a controlled rate so as to maintain the temperature each sample at or above a pre-set temperature differential, with respect to the free space thereinabove, as the temperature of the free space approaches the freezing point of the liquid until evaporation of all the samples is complete and the system is evacuated down to p practically achievable absolute pressure. The system is then isolated and the temperature of the system is allowed to rise, thereby causing any frozen liquid within the system to sublime or re-evaporate. The time taken for the system to reach a steady state value is monitored to indicate the sublimation rate or heat transfer rate of the system and the remaining liquid is evacuated at a rate below the sublimation rate or heat transfer rate to prevent further freezing.</p> |
