Patent ID: 7189325

Claim:
A method for desalting water by reverse osmosis, particularly for desalting seawater, in which saltwater is introduced under a first pressure into a pressure-compensation device comprising at least two piston/cylinder devices and conducted from the pressure-compensation device at a second pressure into a membrane module, the second pressure being higher than the first pressure, wherein desalted water and concentrated saltwater are conducted out of the membrane module, wherein the concentrated saltwater conducted out of the membrane module is continuously introduced at approximately the second pressure into the pressure-compensation device and used therein to approximately apply the second pressure to the saltwater introduced into the pressure-compensation device and to introduce the saltwater into the membrane module, and wherein the introduction of the concentrated saltwater into the pressure-compensation device and the conduction of the concentrated saltwater out of the pressure-compensation device are accomplished by means of controlled main valves, wherein secondary valves, arranged in parallel with the main valves, are controlled such that load peaks during opening and/or closing of the main valves are reduced, for which purpose the secondary valves are open at least during the opening or closing of the respective main valve arranged parallel thereto, and pressure fluctuations are compensated by means of a pressure reservoir arranged upstream of the pressure-compensation device via which the concentrated saltwater is introduced from the membrane module.