GB831478A - Improvements in or relating to evaporators - Google Patents

Abstract

<PICT:0831478/III/1> A multi-stage evaporator, of the type wherein a plurality of stages in series each has a flash chamber whence liquid at saturation temperature corresponding to the pressure in one stage flows to the flash chamber of a further stage at lower pressure, includes a plurality of such stages wherein the bases of the flash chambers are substantially coplanar and wherein a passage for the flow of liquid from the interior of one flash chamber to the interior of a successive chamber includes a portion entering the successive chamber at or near its base and an ascending portion terminating in a discharge outlet located above the base of the chamber, the lower part of the ascending portion converging to a restriction of minimum crosssection near the bottom and the upper part being outwardly flared towards the outlet. The outlet is preferably surrounded by a downwardly-sloping tray. There may be a similar arrangement in the upper part of the chambers for the transfer of distillate from chamber to chamber, and condensation surfaces may be arranged in the upper part of the chambers. Distilland from chamber 1A passes to chamber 3A via channel 6 and outlet 10 having a converging section 7, restriction 8 and flared portion 9, dripping back to the bottom of the chamber over tray 11. Distillate, condensed by bank of tubes 17, from chamber 1 passes to the upper portion of chamber 3 by a similar arrangement through channel 12 and outlet 16.