GB1496983A - Plate type evaporators - Google Patents

Abstract

1496983 Plate type evaporator APV CO Ltd 6 Aug 1976 [4 Sept 1975] 36502/75 Heading BIB In a plate type evaporator comprising a pack of plates- 2 mounted between a fixed head 3 and a movable follower (not shown) so as to provide alternate flow spaces for feed liquid and heating medium, the pack is divided into two sub-packs by a barrier plate 6 having the feed liquid supply ports blanked off and also having an extension 7 which partially blanks off the condensate and vapour discharge port 1 and in conjunction with division bars 8 and 11 and gaskets 9 divides said port into two flow zones 1a and 1b, a tray 12 extending these into the discharge duct 13 beyond the liquid off-take sump 14. The division bars and gaskets may be replaced by a single tray which may extend into the discharge duct (Fig. 2 not shown) or overlap the tray therein (Fig. 3 not shown). In use the first stage of the evaporation takes place in the sub-pack situated between the barrier plate 6 and the head 3 and the concentrate and vapour passes through flow zone 1a and duct B to a conventional gas-liquid separator, the liquid from which passes to the other subpack, the concentrate and vapour from which passes through flow zone 1b, the liquid therein being withdrawn by sump 14 and the vapour mixing with the vapour from zone 1a for passage to the gas-liquid separator. The flow spaces between the plates may be divided into 2 or more zones in accordance with U.K. specification 1412414, allowing of 3 or more stages to be provided within a single pack. In this case an additional sump (14a) may be provided in the outflow from zone 1a (Fig. 4 not shown).