Abstract: The invention relates to an annular module for filtration by reverse osmosis of a liquid under pressure. This module comprises a support formed by a tubular spool (1) having a central open volume along the entire spool height and provided with a slit (4) issuing into its peripheral face and extending along a generatrix. This slit communicates with a duct (5) formed in the thickness of the spool and issuing outside thereof at the end of a stud (3). The reverse osmosis filtration membranes (6, 7) are helically wound around the spool; the inner turn of the membranes are impermeably fastened on the peripheral surface of the spool in such a manner that the slit (4) enters between the two membranes of said inner turn.

Abstract: The invention relates to an apparatus for the production of fresh water from seawater, intended to be immersed into the marine medium. The apparatus comprises one high pressure chamber (1) containing a selective semi-permeable reverse osmosis membrane (11) and a bell chamber (14) having an internal axial piston permitting by a multiplier effect, to obtain at the interior of the chamber (1) a pressure equal to the exterior pressure multiplied by a ratio S/s of the working surfaces of the bell chamber and the internal piston. The semi-permeable membrane communicates across a separation wall (3) of the high pressure chamber with the interior volume of the bell chamber (14). This internal volume is placed in communication with the surface by a flexible tube (25) in such a manner as to play the dual role of, on one hand, a subatmospheric gas chamber, and on the other hand means for receiving fresh water after osmosis across the membrane.

Abstract: The invention concerns an apparatus for purifying primary water so as to produce in batchwise manner potable fresh water by reverse osmosis in the course of discontinuous operational stages. This apparatus comprises a primary-water chamber (3), a stopper (7) to fill it, a potable-water collecting connector (12) and stub, a semi-permeable membrane (10) housed in the chamber (3), a movable piston (15) which may enter said chamber between a retracted position and a maximum penetration position, and mechanical means to drive the piston which include an intake handcrank (23), two meshing gears (18, 22) and a screw (17) driven by one of the gears and supporting the piston. The dimensions of the chamber (3) are such that its total available capacity (V.sub.1) is at least three times the volume (V.sub.2) swept by the piston in its displacement between the retracted and the maximum-penetration positions.

Abstract: The invention concerns a fresh-water producing apparatus to be immersed in a marine medium and of the type comprising at least one reverse-osmosis selective semi-permeable membrane.This apparatus comprises three stages: a fresh-water stage consisting of collecting means for the produced chamber provided with a semi-permeable membrane placed between this chamber and the fresh-water collecting means; and, a third stage comprising a mobile piston and an hermetic chamber having a gaseous atmosphere. The piston is designed to enter in variable depth the high-pressure chamber by one side having an effective area s and comprising an opposite side with an effective area S exceeding the area s and arranged to be at the pressure of the marine medium.

Abstract: The invention relates to a control device for the feeding and drainage of a column or a treatment station such as a demineralization station.The device includes a centralized distribution valve mounted on top of the column; which is equipped with at least three inner chambers having movable pistons adapted to connect various ports which the valve contains. The valve is connected with driving means, e.g., a hydraulic dispenser adapted to generate the shifting of the movable pistons for the purpose of positioning them in several specific positions.The device of the invention can especially be used in conjunction with demineralization columns containing ion exchanging resins. The device makes it possible to initiate and progress through the various operating phases or modes either automatically or semi-automatically.