* * * INSIGHT * * *

How important is the flatness of the shelves of a freeze dryer?

by

Thomas A. Jennings, Ph.D.

It has been my experience when talking to company personal who are engaged in purchasing a freeze dryer, that the main focus is often on the refrigeration system, i.e., the range of shelf temperatures and condenser temperature and the vacuum capabilities of the pumping system. Without question these and other considerations like process controls and data acquisition are some of the more important issues to be addressed. And yes the shelf surface is a key factor for that will relate to product capacity of the dryer. It then becomes a matter of just engineering the dryer in accordance with the process specifications required by the purchaser.

Yet, it is often surprising to me to find that with so many details listed often little or no attention is given to flatness of the shelves. Although I must give credit to others like the Novice who asked the question “Are they flat?” in INSIGHT Vol. 2 No. 11 and also following references [1-3]; however, little heed is often given to such advice and the shelf flatness tends to be overlooked. Therefore it is the objective of this INSIGHT to make the reader more aware of the important role that the flatness of the shelves play in the lyophilization or freeze drying process.

Volume 5 No. 12                                                                                       December 2002

4 Pages          4 References           0 Figures

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