Patent ID: 8173003

Claim:
A turn-back electrodeionization device comprising: a central pipe which acts as an electrode, an outer crust which is concentric with the central pipe, and an outside electrode; an upper and a lower cover which are disposed at the ends of the central pipe and the outer crust respectively; anion exchange membranes and cation exchange membranes which are alternately positioned between the central pipe and the outer crust forming a concentrate chamber and a dilute chamber at two sides of the ion exchange membranes, respectively; and ion exchange resins filled in at least one of the concentrate chamber and dilute chamber; wherein the anion exchange membranes and cation exchange membranes wind around the central pipe to form a helical wound cylindrical unit; and wherein the dilute chamber includes two ends parallel to the central pipe that are sealed and two ends perpendicular to the central pipe that are open and is separated into an inner side dilute chamber unit and an outside dilute chamber unit wherein the inner side dilute chamber unit and the outside dilute chamber unit extend straight-through along the axial direction such that dilute sequentially passes through the outside dilute chamber unit and inner side dilute chamber unit in a turn-back way.