Patent ID: 9370747
Filing Date: 2016-06-21
CPC Classification: B01D,C02F

Claim Text:
1. A method of reducing the total dissolved solids of a solution, including the steps of: providing a unit having at least two chambers; conveying a feed solution to at least one first chamber of said unit; conveying a draw solution to at least one second chamber of said unit that is adjacent to said at least one first chamber, wherein a semi-permeable membrane arrangement is disposed between each of said first and second chambers, wherein said semi-permeable membrane arrangement comprises an apertured material, the apertures of which contain semi-permeable membranes, wherein said apertured material is in the form of a ring, further wherein the draw solution has a greater molar concentration than does the feed solution, further wherein solvent from the feed solution is adapted to be drawn through the semi-permeable membranes of the semi-permeable membrane arrangement into the draw solution, thereby reducing a solute concentration of the draw solution and increasing a solute concentration of the feed solution, and wherein localized solute depositions occur within the semi-permeable membranes and/or on an external surface of the semi-permeable membranes that faces a feed and draw solution chamber; providing at least one paddle in said at least one first chamber and in said at least one second chamber; positioning said at least one paddle in said at least one first chamber and in said at least one second chamber at a distance from opposite external surfaces of the semi-permeable membranes, such that said at least one paddle does not contact said opposite external surfaces of the semi-permeable membranes; continuously sweeping the opposite external surfaces of the semi-permeable membranes with at layer of solvent by moving said at least one paddle to at least reduce the solute depositions on the surface facing the feed solution chamber and to remove liquid permeate molecules from that external surface of the semi-permeable membranes that faces a draw solution chamber; and withdrawing, from said unit, feed solution that is more concentrated than that conveyed to said unit and draw solution that is more diluted than that conveyed to said unit.