Patent ID: 8661648

Claim:
A method for making a spiral wound module comprising: providing a permeate collection tube; providing at least one roll of membrane sheet wherein the membrane sheet comprises a membrane layer and support layer which are rolled up in a roll direction, wherein the support layer of the membrane sheet comprises a non-woven fabric comprising fibers orientated in the roll direction; removing a first and second rectangular section of membrane sheet from at least one roll, wherein each section has four edges and two opposing sides including a membrane side and a support side; forming a membrane envelope by: overlaying the first section of membrane sheet upon the second section such that the roll direction of both sections are parallel to each other, aligning the edges of both sections of membrane sheet with each other, and sealing both sections of membrane sheet together along three of the aligned edges such that an unsealed fourth edge is parallel to the roll direction of both sections and defines a proximal edge; and winding the membrane envelope concentrically about the permeate collection tube such that the proximal edge of the membrane envelope is in a proximal position along the permeate collection tube.