Abstract: Membrane disk assemblies include membrane disks which have feed and residue apertures formed through and bounded entirely by a perimetrical edge region of the disk. Preferably, the feed and residue apertures are formed though a fluid-impermeable support rim positioned in the perimetrical edge region of the membrane disk which serves to sealably bond the exterior membrane sheets and at least one interposed permeate carrier sheet one to another. Most preferably, the support rim includes inwardly directed lobes through which the feed and residue apertures are formed. The membrane disks will also include a central permeate aperture in fluid communication with the carrier sheet interposed between the pair of membrane sheets. When a number of such membrane disks are assembled in stacked relationship with the feed, residue and central permeate apertures registered, there will be formed respective feed, residue and permeate passageways through the stack.

Abstract: A stacked membrane disk module has a number of membrane disks interleaved with seal rings and includes a biasing subassembly for maintaining a compressive force between the membrane disks and interleaved seal rings so that the module can be repeatedly pressurized/depressurized. The membrane disks preferably include a central first aperture and a pair of second apertures which are radially spaced from the central first aperture. These apertures will thus be respectively registered when a number of such membrane disks are stacked between a pair of end plates so as to establish a central fluid passageway and a pair of second fluid passageways. A rigid perforated tube is positioned within the central fluid aperture and is connected to the end plates so that at least one of the end plates is capable of being axially displaced relative to the perforated tube. A biasing member (e.g.