Potted flat sheet membrane filtration module

A membrane filtration element comprising:

• a bundle of planar filtration sheets, wherein each filtration sheet comprises,
• a pair of membranes disposed in stacked spaced relation to one another each membrane having a feed side and a permeate side
• a cylindrical housing in receipt of the bundle of planar filtration sheets, the cylindrical housing having a feed end and that is essentially free of pores in the outer radial surface;
• for each of one or both ends of the housing, a quantity of potting material, the quantity being disposed at the end of the housing for which it is provided, extending in annular relation radially inwards from an inner surface of the cylindrical housing and tapering in thickness as it extends from the end of the housing from which it is provided, the potting material being provided such that at least a central portion of the housing is free of potting material;
• and,
• wherein
• in use, liquid is forced through the membranes via a pressure differential between the feed side and the permeate side, the filtered liquid being collected as permeate which travels, both from the bundle and through the housing, in a direction perpendicular to the longitudinal axis of the housing;
• each of the plurality of filtration sheets has a width and wherein at least two of the widths of the plurality of filtration sheets are different from each other, the filtration sheets are arranged in the bundle with spaces between the filtration sheets to provide channels between the filtration sheets through which feed fluid can enter at the feed end, and
• the filtration sheets are parallel to a central longitudinal axis of the housing.