Spirally wrapped reverse osmosis membrane cell

A spirally wound module for use in separating a permeate from a fluid feed mixture comprising:

• a product tube serrated along its outer surface, the bottom surface of the serrations having a plurality of spaced apart apertures for communicating between said bottom surface and the interior thereof;
• a highly porous product spacing means having protrusions along one surface thereof;
• a permselective membrane;
• said product spacing means and said membrane are folded over said product tube whereby said protrusions are positioned on the side of said product spacing means opposite said product tube serrations;
• said product spacing means overlaps said serrations and said membrane sandwiches adjacent layers of said product spacing means therebetween, the edges and free outer ends of the membrane layer and highly porous spacing means are sealed together;
• and
• first and second highly porous brine spacing means having channels on one surface thereof parallel to the axis of said product tube, the brine spacing means sandwich at least a portion of the folded layers of membrane and product spacing means therebetween, whereby when the membrane, product spacing means and brine spacing means are wound about the product tube at lease some layers of product spacing means and membrane have first and second brine spacing means therebetween and the channels of said first and second brine spacing means are opposing.