Stacked assembly for reverse osmosis

Claim 1

A stacked assembly for reverse osmosis comprising a plurality of semipermeable membranes superposed on rigid support plates, wherein: (a) the support plates are of a flat generally rectangular shape and are identical with each other, while only a single semipermeable membrane is interposed between each pair of consecutive plates in the assembly; (b) each plate comprises a receiving face and a delivery face, the receiving face being planar and formed in a centrally located region thereof with an array of intercommunicating grooves, whereas the delivery face comprises: a planar abutment region extending along the whole contour of the face for sealing engagement with the respective membrane, a plurality of elongate, shallow flow-conveying beds formed in a centrally located region of the delivery face surrounded by said abutment region, said beds being parallel to a pair of opposite edges of the plate and having each its opposite end portions extending beyond the said centrally located region of the receiving face; (c) the bottom of each of the end portions of each bed is formed with a first through-aperture and with a flat bossage which surrounds the mouth of the aperture and is formed by a plurality of sectors defining radial passages therebetween, the height of said bossage being less than the depth of the respective end portion of the bed; (d) at least one second through-aperture is formed in each plate within the area of said planar abutment region, this aperture being in communication with the said array of grooves in the receiving face of the plate; (e) each of the membranes is formed with apertures matching the said first and second through-apertures in the plates; and (f) each of the membranes is sealingly clamped to the receiving face of a respective plate both by the abutment region of the delivery face of the adjacent plate and by means of a plurality of mutually interchangeable plug members having each a shank portion which is forcibly engaged in the corresponding first through-apertures through the matching apertures in the membrane and protrudes axially from a disk portion integral with the shank, said disk portion being backed-up by the bossage sectors of the said adjacent plate thereby to clamp the membrane, the shanks of some of said plug members being axially open to allow passage of liquid therethrough while the shanks of the remaining plug members being blind to prevent passage of liquid through-apertures in which they are engaged to define first flow path means for a fluid between each membrane and the delivery face of the adjacent plate, said second through-apertures being in communication with each other and the grooves of each receiving face to define second flow path means for receiving only that portion of said fluid which passes through said membranes.