701,888. Drying by freezing and subsequent sublimation. VOGT, A. June 20, 1952 [June 26, 1951], No. 15600/52. Class 34(2) [Also in Group XVII] In a process for the freeze-drying of biological substances &c. to be kept sterile in containers 4 that have been closed under sterile conditions and frozen, the container closure is removed within a vacuum drying chamber 3, the frozen material 5 is dried by sublimation of the ice and the closure restored, all under vacuum. The chamber 3 has parallel walls 1, 2 of which wall 1 has at 9 an aperture for passage of the container neck 7 the shoulder 6 of which fits against gaskets 8. A metal screw cap 17 secures a rubber closure 11, having a sealing rim 12, and a washer 18 and the cap has radial lugs 19. A tool for removing and replacing the closures has a guide casing 21 in which moves a spindle 26 carrying a driver member 25 having slots 27 to engage the lugs 19 of the screw cap 17, the spindle 26 being operable by a handwheel 28. A lip packing 29 provides for vacuum-tight guidance. of the spindle in its casing 21.
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