Multieffect evaporator

Claim 1

A multiple effect evaporator, comprising: a housing; a plurality of substantially vertical parallel tube sheets connected to the interior of said housing; a plurality of effects in said housing each effect defined between a pair of said tube sheets the effects being substantially aligned; a plurality of substantially aligned bundles of substantially horizontally extending condenser tubes, one of said bundles being located in each of said effects, the constituent tubes of each said bundle being supported adjacent one set of open ends thereof by one of said tube sheets through which said ends extend; a plurality of openwork grids connected to the interior of said housing through each of which the tubes of one of said bundles extend; sealing means for sealing said sets of open ends to said tube sheets; non-condensible gas discharge vents with restricted diameter compared with the inner diameter of said tubes, connected to the ends of said tubes opposite the tube sheet ends; solution introducing means for introducing solution into the upper portions of each effect in such a manner that it flows downwardly under gravity in film form over and around said tubes; heated vapor introducing means for introducing heated vapors into the open ends of the tubes of the first and hottest effect to undergo heat exchange with the downflowing solution in said effect, as a result of which a portion of the solution vaporizes and at least a portion of the vapors condenses in said tubes; vapor passing means for passing the vapors from one effect into the tubes of a subsequent effect, in such a manner that vapor flow in each effect is in a direction substantially parallel to the tubes in that effect and the passage of vapors throughout all the effects involving substantially no changes in flow direction; and collecting means for respectively collecting and removing condensate and concentrate products.