GB889157A - Improvements in condensing surface structures particularly for use in distillation apparatus - Google Patents

Abstract

<PICT:0889157/III/1> <PICT:0889157/III/2> In a distillation apparatus in which a condensible vapour, e.g. steam, is supplied to one surface of a barrier of good heat conductivity, the distilland being distributed in the form of a thin film on the other surface of the barrier, the surface to which the vapour is supplied is fluted vertically in such a way that the valleys of the undulations form narrow grooves, for the run-off of condensate, and the crests of the undulations are large in comparison with the valleys, preferably at least twice as large, the purpose of the arrangement being to effect efficient heattransfer through the barrier. A typical undulation is shown in Fig. 3, in which a relatively narrow valley 5 is formed between relatively extensive crests 4. Mathematical formulae are given in the Specification whereby suitable dimensions for the valleys and the crests can be computed in any particular case, the dimensions depending on, inter alia, the latent heat of condensation of the vapour and the density, viscosity and surface tension of the condensate. Fig. 4 shows the application of the invention to a compression apparatus suitable for the distillation of sea-water. The sea-water is supplied by pipe 12 to a distributer 13 which spreads it as a film over the inner surface 2 of a cylinder 1, the distribution being assisted by wipers 17 mounted on an axial shaft 14 rotated by a motor 15. The distillation residue is discharged through pipe 29, and the vapour rising from the surface 2 passes through passages 20 in the distributer 13 to a compressor 10, which delivers it to the space between the cylinder 1 and an outer cylinder 27. The outer surface of the cylinder 1 is fluted as described above, and condensate flows down the grooves to a discharge pipe 28.