CPC B01D 63/103 (2013.01) [B01D 2313/086 (2013.01); B01D 2313/143 (2013.01)] | 23 Claims |
1. A spiral wound membrane element comprising,
(a) a central collection tube having a first set of openings along its length to receive permeate flow;
(b) at least one filtration envelope extending outwardly from and wound about said central collection tube, said at least one filtration envelope comprising two layers of membrane sheet and a permeate carrier layer sandwiched between said layers of membrane sheet; said permeate carrier layer being in direct fluid communication with the first set of openings of said central collection tube;
(c) at least one feed spacing layer providing feed spacing adjacent the at least one filtration envelope, wherein each of the at least one feed spacing layer contains feed spacing strips attached to a surface of the membrane sheet opposite the permeate carrier layer, said feed spacing strips are in continuous contact with adjacent membrane sheets in either the axial direction or the longitudinal direction, wherein each of the feed spacing strips has a thickness profile and wherein at least one of the feed spacing strips has a thickness profile that reflects a nonconstant thickness of said at least one of the feed spacing strips.
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