US 5,964,043 AGranted

Freeze-drying process and apparatus

AssigneeGlaxo Wellcome Inc.

InventorsDominic M. A. Oughton, Philip R. J. Smith, Donald B. A. MacMichael

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Abstract

A process and apparatus for freeze drying of liquid material in a vessel in which the vessels are moved automatically through various stages including loading vessels onto racks, washing vessels in an inverted position, sterilizing vessels and racks, filling vessels with a liquid material, rotating the vessels and the liquid material contained within each vessel at a speed that allows the liquid to form a shell against the inner surface of the vessel, subjecting the vessels and the liquid material contained therein to freezing conditions sufficient to freeze the material into the form of a shell and then moving the rack and the vessels containing the frozen material through a vacuum drying chamber in which the frozen liquid material is dried.

Claims34

Dependent claims

A process for carrying out freeze drying of liquid material in a vessel, in which vessels are moved automatically through various process stages up to and including being subjected to vacuum drying conditions, said process stages comprising:

(a) loading racks with vessels to be filled, such that said vessels are held apart at individual locations in the racks, each said vessel comprising a vessel base and a vessel wall having an outer surface and an inner surface;
(b) washing the vessels and racks, said vessels being in an inverted position so that washing water will drain therefrom;
(c) sterilising the vessels and racks;
(d) filling the vessels with liquid material to be frozen therein;
(e) rotating the vessels containing the liquid material to be frozen at a speed not less than that required to maintain the liquid in a shell of substantially uniform thickness against the inner surface of the vessel wall by the action of centifugal force while subjecting the liquid material to freezing conditions sufficient to freeze the material as said shell, wherein vessels are removed from the racks and are rotated remote from the racks and after a preset time to complete freezing, the rotating is stopped and the vessels are returned to the racks;
and
f) moving the racks with the vessels containing the material that has been frozen held at individual locations into and through a vacuum drying chamber to dry the material that has been frozen.

4 more elements

Apparatus for freeze-drying a liquid material contained in a sterilised vessel having a vessel base and vessel wall with an inner surface and an outer surface so that said liquid material forms a shell of substantially uniform thickness on the inner surface of said vessel wall and in which a plurality of said vessels are moved automatically through various process stages up to and including being subjected to vacuum drying conditions;

said apparatus comprising:
racks which include individual locations for locating vessels such that they are held apart;
a washer for washing and a steriliser for sterilising the vessels and racks;
rotatable grippers for removing the vessels from the racks and returning the vessels to the racks, and for holding a vessel and rotating said vessel about a longitudinal axis thereof at a high speed so as to maintain liquid material against the inner surface of the vessel wall by centrifugal force;
filling means connected to a liquid material supply for introducing liquid material into the vessel;
freezing means for freezing the liquid material in the form of a shell of substantially uniform thickness against the inner surface of the vessel wall;
a vacuum drying chamber containing a heater;
and
a conveyor to move racks holding the vessels containing the material that has been frozen into and through the vacuum drying chamber, and to move subsequent racks loaded with vessels into position for filling and freezing.

6 more elements

Dependencies are inferred from the claim text.