Multiple effect evaporator apparatus

Claim 1

A multiple effect evaporator comprising: a vertically oriented cylindrical shell; a plurality of superposed chambers in said shell formed by horizontally disposed, vertically spaced tubesheets; a vertical heat exchange tube bundle provided within each of said chambers for the serial passage through said tube bundles of a solution to be evaporated, the lower ends of said tubes being fixed within said tubesheets; vessel means, disposed upon the upper ends of each of said tube bundles, provided within each of said chambers for receiving a heated solution and vapor from the lower ends of said tubes of the immediately preceding bundle of heat exchange tubes and which vessel means fluidically communicates, through a pressure difference maintaining means for maintaining a pressure difference between the pressure within said vessel means and that within the immediately succeeding vessel means and a solution distribution means disposed below said pressure difference maintaining means and above said upper ends of said tubes for defining a solution containing chamber between said distribution means and said tubes, within said vessel means, so as to uniformly distribute said solution into a succeeding bundle of heat exchange tubes, and through said succeeding bundle of heat exchange tubes, with said succeeding vessel means therebelow for conducting the resulting amount of said solution to said succeeding vessel means so as to evaporate said solution within said succeeding bundle of heat exchange tubes and to condense the major portion of said vapor from said preceding bundle of tubes about the tubes of said succeeding bundle, said vapor being used as a heat source, and including separating means for separating said vapor from said solution and for conducting said separate vapor from said preceding bundle of heat exchange tubes into said respective chamber containing said succeeding bundle; and a plurality of vapor and non-condensable gas flow passageway means for successively interconnecting the condensing portions of said chambers for causing a directional vapor flow in conjunction with said separated vapor flow from said vapor separating and conducting means about each of said bundles of heat exchange tubes within each of said condensing chambers and for conducting said flow from a preceding condensing chamber to a succeeding condensing chamber for increasing the heat exchange coefficient of said heat exchange tube bundles by preventing the stagnation of the non-condensed gas around said tubes.