GB644631A - Improvements in or relating to rotors for centrifugal stills - Google Patents

Abstract

<PICT:0644631/III/1> A rotor for a centrifugal still, and particularly for a high-vacuum unobstructed-path still wherein the distilland is in the form of a film, is of massive construction, has a thickness at the vaporizing area between 3/16 inch and 1 1/2 inches, and is made of material which has a coefficient of thermal conductivity in excess of 90 B.T.U.-foot-hour-degree Fahrenheit units. The temperature of the vaporizing surface using such a rotor heated by an electric element beneath it is maintained nearly uniform at all points, and decomposition of a heat-sensitive distilland is less than when a thin rotor is used. For a rotor of 30 inch diameter, the thickness is in the range 1/4 -\ba1/2 inch. The rotor may be made of <PICT:0644631/III/2> aluminium, copper, gold, silver, or magnesium, or various plated combinations of such metals, or an alloy of sufficiently high thermal conductivity. A rotor constructed of copper with a silver coating has excellent performance characteristics. Figs. 2 and 3 show rotors which are suitable for small and large stills respectively. In either case the rotor is rotated by a shaft (not shown) attached at hole 12. The heating element underneath the rotor is placed in operation. The distilland is introduced at area 10, and centrifugal force drives it over the vaporizing area 11 into collecting gutters. In an example, comparison is made between the performance of a 3/4 inch aluminium rotor and a 3/16 inch steel rotor in the concentration of vitamin A from fish oil. The loss of vitamin A using the thick aluminium rotor was about one-half the loss sustained when the thin steel rotor was used.