Abstract: An evaporation product discharged from a lower end a falling-film evaporator enters a downpipe (7), makes a 180° turn at a bottom of the downpipe, and moves upward through an annular rising channel (9) defined between the downpipe and an intermediate housing (10). As the evaporation product moves along a spiral path (12) defined by the spiral fins, centrifugal forces urges water droplets and impurities to a radial outward periphery where they pass through openings (13) in the intermediate shell as pure steam continues through the spiral path and out a pure steam outlet (21). A cooling jacket (15) chills a peripheral wall of an outer shell (14) adjacent the holes such that the discharged water droplets condense on the outer shell and flow down a reject water return path to a reject water reservoir at the bottom of the outer shell.

Abstract: An evaporation product discharged from a lower end a falling-film evaporator (1, 2) enters a downpipe (7), makes a 180° turn at a bottom of the downpipe, and moves upward through an annular rising channel (9) defined between the downpipe and an intermediate housing (10). As the evaporation product moves along a spiral path (12) defined by the spiral fins, centrifugal forces urges water droplets and impurities to a radial outward periphery where they pass through openings (13) in the intermediate shell as pure steam continues through the spiral path and out a pure steam outlet (21). A cooling jacket (15) chills a peripheral wall of an outer shell (14) adjacent the holes such that the discharged water droplets condense on the outer shell and flow down a reject water return path to a reject water reservoir at the bottom of the outer shell.