Multi-leaf membrane module

Claim 1

A membrane separation apparatus for separating a feed mixture into a permeate stream and a retentate stream comprising: (a) a housing, having means for feed inlet, retentate outlet and permeate outlet; (b) a pressure resistant compartment, having feed inlet and retentate outlets in nominal register with the feed inlet and retentate outlet of the housing, disposed within said housing; (c) plurality of flattened tubular semipermeable membranes, arranged in a parallel stack arrangement, and separated individually by feed spacers which do not extend to the full length of the tubular membrane at each end longitudinally, each tubular membrane internally containing a permeate spacer extending the full length of said membrane tube and each flattened tube being open at both ends, the feed spacers and flattened tubes containing the permeate spacer being alternately longitudinally layered to form a stack disposed in said compartment; (d) clamping means to seal the membrane stack ends under pressure and to prevent the feed from exiting the compartment through the membrane envelope layers to the permeate side, the clamping means longitudinally positioning and maintaining the tubular membranes stack in the compartment by clamping tubular open ends in the arrangement forming membrane-to-membrane seals, such that during operation the permeate permeating through the membranes exits internally from the membrane envelope via the permeate spacer into the permeate outlet, while the retentate exits through the retentate outlet.