Freeze-drying today and tomorrow.

The freeze-drying process and equipment have been improved over the years; the cycle times have shortened and the dried products have improved as a result. This talk will deal with these improvements and how we have progressed from the early systems to where we are today. Such areas of discussion will include: vacuum pumping systems, how they are sized and designed to meet the needs for general and special applications; heat transfer systems, and their use in maintaining the drying profile; condensing surface design, and what is best for certain types of dryers; controls and instrumentation, and how these have played a big part in the drying process and have made it possible to get repeatability; refrigeration systems, and the part they play in the performance of freeze-drying; and lastly the effect of internal stoppering, bottomless trays, and other items such as these have had on the present state of the art. It goes without saying that there have been many changes and there will continue to be changes and we shall endeavor to look into the future--as to what might well bo some of these changes. Included in the talk will be a number of slides and illustrations to point out the various items as they are discussed.