Boiler/condenser assembly for high efficiency purification system

A boiler and condenser device comprising;

• a plate-in-frame heat exchanger including a plurality of vertically extending common plate members, a plurality of alternating boiling and condensing chambers on opposite sides of said common plate members, means for conveying feed material into said boiling chambers, means for conveying vapors from said boiling chambers into said condensing chambers, a face of each common plate member in a condensing chamber having a corrugated herringbone surface configuration, a plurality of diagonal vapor flow paths for directing vapors from the boiling chambers diagonally across the condensing chamber, the corrugated surfaces of oppositely facing adjacent common plate members having portions in abutting relationship to form contact points between adjacent common plate members, said contact points providing accumulation points for liquid forming on condensing surfaces of said common plate members, a plurality of diagonal liquid flow paths adjacent the diagonal vapor flow paths for directing the liquid to flow down the condensing surface into run-off streams, and a run-off area on the condensing surfaces communicating with the lower ends of the diagonal liquid flow paths for carrying a large volume of liquid off the plate members while occupying a small portion of the total surface area of the plate.