Semipermeable membrane cartridge for use with a pressure container

The combination of a spiral wound membrane cartridge and a pressure-resistant container for receiving said cartridge, said cartridge including a permeate collection tube with a spiral winding of a plurality of leaves each of which is a laminate of a semipermeable membrane sheet, a permeate transfer sheet and a porous grid sheet, only one of said leaves having an extension of said porous grid sheet of sufficient length to encompass the circumference of said cartridge whereby upon insertion of said cartridge into said container and release of said cartridge, said cartridge will undergo slight unwinding with the extension being in intimate, continuous contact with the interior surface of said container except along a single line at the free end of said extension,

• said container including a cylinder having a closed end pierced by a liquid entry pipe with a spacer disposed adjacent said closed end to limit the extent of insertion of said cartridge to create an entry plenum,
• said cylinder having an open end spaced from said closed end with an annular inner groove formed at said open end partially defined by a shoulder, said container further comprising a removable plate seating against said shoulder and held in position by a snap ring, said cartridge being spaced from said shoulder to form an exit plenum,
• said permeate collection tube extending through a central hole in said plate and being sealed to said plate by means of an "o" ring.