GB1001673A - Improvements in heat-transfer apparatus - Google Patents

Abstract

1,001,673. Evaporating liquids in film-form; distilling saline water. GENERAL ELECTRIC CO. Feb. 15, 1963 [March 1, 1962], No. 6243/63. Heading BIB. [Also in Division F4] Liquid is evaporated by causing it to flow down one side of a metal wall, which is: heated on the opposite side, the wall having vertical corrugations with a pitch P of from 0À05-0À5 inch, and of height H from 0À05- 0.25 inch, and the length L of the wall compares to the height H in the ratio of 50:1 - 5000:1. Initially the liquid flows down the grooves 14; the vapour-bubbles are formed which splash the liquid over the adjacent ridges in a thin film. Vapours may be condensed on a similar heat-exchange wall. The distillation apparatus for saline water shown in Fig. 3 is divided into three compartments 26, 28 and 30 by two corrugated walls 22 and 24 of the form specified above. Steam, from a boiler or a turbine, is supplied through pipe 32 into compartment 26 so that the left-hand side of wall 22 is heated. Preheated saline water, supplied to compartment 28 through pipe 36, flows down the right-hand surface of wall 22. About 75% of this water evaporates ; and the vapours are condensed on the lefthand side of wall 24. Distilled water is withdrawn through pipe 42. The right-hand side of wall 24 is maintained cool by flowing saline water, supplied through pipe 46, over it. The heated saline water, withdrawn through pipe 50, is supplied to inlet-pipe 36. Concentrated salt solution is withdrawn through pipe 40. The length of wall 22 and the rate of supply of saline water are chosen so that no precipitation of salts will occur from the distilland. If desired, the vapours evolved from the saline water may be condensed on the opposite side of the same heat transfer wall from which they were evolved, provided a sufficient elevation in pressure is first given the vapours.