Membrane separation cell

Claim 1

A membrane separation cell for separating a permeate from a feed solution, comprising: a stack including a plurality of supporting plates each supporting a membrane on each of its opposite faces and defining a permeate compartment between the membrane and the respective face of the supporting plate; and a plurality of separator plates each interposed between the membranes of adjacent supporting plates and defining a feed solution compartment between the separator plate and the respective membrane; said separator plates being formed with passageways therebetween connecting the feed solution compartments in series through the stack such that the feed solution flows through each feed solution compartment in an inward direction across one face of the separator plate and in an outward direction across the opposite face of the separator plate; the opposite faces of the separator plates being each formed with a thickened outer rim circumscribing a recessed area across which the feed solution flows as a thin layer in a radial direction in contact with the face of the adjacent membrane; said passageways through each separator plate including a peripheral array of openings formed therethrough just inwardly of said thickened outer rim; each membrane supporting plate being apertured at its center and each separator plate being non-apertured at its center; said stack further including: a ring insert interposed between the center of each separator plate and the adjacent membrane for pressing same against the inner rim of the respective supporting plate around its central aperture; a pair of cover plates at the opposite ends of the stack and having extensions projecting radially outwardly of the membranes, supporting plates and separator plates; and a plurality of rods passing through the cover plates outwardly of the membranes, supporting plates and separator plates, for clamping them all together.