Patent ID: 6267890
Filing Date: 2001-07-31
Classification: B01D

Abstract:
A method of operating a spirally wound membrane module comprising a plurality of membranes wound about an axis of the module to form a roll of said membranes and to form feed water channels between said membranes into which feed water flows via a front end of the roll and from which nonpermeated water flows out via a rear end of the roll, the method comprising:a) providing a module comprising a plurality of membranes having a form of an envelope, permeated water spacers for forming permeated water channels disposed inside the membranes, and feed water spacers for forming said feed water channels disposed between the membranes,wherein each of said plurality of membranes is formed in a substantial rectangle having first, second, third and fourth edges, the first, second and third edges being closed and a portion of the fourth edge being partially opened to define a permeated water opening, and closed at a rest thereof to form a blocking portion,wherein the membranes are wound upon a shaft of the module to form a membrane roll so that the first edges perpendicular to fourth edges are in contact with the shaft and the fourth edges are exposed on the rear end of the membrane roll, and the second edges opposite to the fourth edges are exposed on the front end of the membrane roll, andwherein each feed water channel between the membranes is closed entirely along the third edge, closed along a portion of the fourth edge corresponding to the permeated water opening, and opened along a portion of the fourth edge corresponding to said blocking portion to form a nonpermeated water opening; andb) passing feed water into said feed water channels of said membrane module such that permeated water flows out via said permeated water openings and such that nonpermeated water flows out via said nonpermeated water openings.