SPIRAL WOUND MEMBRANE ELEMENT AND PERMEATE CARRIER

摘要

A permeate carrier for a spiral wound membrane element has two or three layers, for example of tricot construction. The two outer, or only, layers resist movement of the membrane sheet into permeate channels in the permeate carrier. The total thickness of the permeate carrier sheet may be similar to the thickness of typical tricot permeate carrier sheets. The permeate carrier sheet may be coated to make its surfaces hydrophilic. The coating may be, for example, a cross-linked polyvinyl alcohol (PVA) or polyvinyl pyrrolidone (PVP). In the spiral wound element, a permeate carrier sheet may be wrapped in one or more layers around a central tube. Channels in the permeate carrier sheet are oriented helically relative to a longitudinal axis of the central tube.