7. A Closed System for Batch Freeze-drying of Liquid Material by the Use of Virtical Tube(Papers presented at the 36th Annual Meeting, April, 1990, Tokyo)

Abstract

Up to now, in a conventional freeze-drying method for the bulk pharmaceuticals and other liquid materials, there has been employed a tray/shelf system, and the matter of complicated tray/material handling under the open space is one of the most important problems to be solved in this field (cf.Cooper,1984). Previously authors presented a paper on the closed type non-tray continuous freeze-drying system for liquid by using vertical tubes (1988). In this system, the substantial part of the liquid product poured into the drying chambers is not subjected to the freeze-drying, but is drained in the from of liquid. In the continuous multi-chamber system, the drained liquid from the chamber is charged into the next chamber together with newly supplied material so that the chambers are reiteratedly and circulatively used during continuous operation period. However, there are some materials for which a batch system is more recomendable from the quality view point. This presentation discusses a closed type batch freeze-drying system for liquid materials. By installing a simple device additionally above the bundle of tubes in the chamber, almost all of the liquid material poured into the chamber is formed into desired frozen layers, leaving behind space necessary for water vapor to flow in all the tubes, and the drain is reduced to come only "from one" of the tubes instead of "from all". The new device contacts neither the liquid nor the dried cake at all and that the chamber having no complicated structure, internal cleaning and sterillizing can be easily performed without fear of contamination.