Patent ID: 7407585

Claim:
A water purification system comprising: a pump ( 10 ) having an aspiration side adapted to aspirate water to be purified and a discharge side adapted to discharge under pressure water entering the pump; liquid phase separation means ( 11 ) operating by permeation through at least one selective permeability membrane as a result of a pressure gradient and having an inlet in fluid communication with the discharge side of the pump, a permeate outlet, and a retentate outlet; electrodeionization means ( 12 ) having a permeate inlet in fluid communication with the permeate outlet of the separation means and a purified water outlet; means ( 16 ) for evacuating the retentate from the system, in fluid communication with the retentate outlet of the separation means, and incorporating a restriction ( 19 ) to reduce the retentate flowrate at the outlet of the system; and communication means ( 17 ) whereby the evacuation means communicate with the aspiration side of the pump, between the retentate outlet of the separation means and the restriction and incorporating a pressure regulator ( 21 ) to maintain, in conjunction with the pump ( 13 ), a substantially constant predetermined pressure at the inlet of the separation means; which system is characterized in that a flowrate regulator ( 22 ) is disposed in the permeate flow path from the separation means to the electrodeionization means to maintain a substantially constant predetermined permeate flowrate, said flowrate regulator comprising a deformable member configured for reducing the effective flow section through said flowrate regulator in the event of an upstream pressure rise, so as to maintain the permeate flowrate at said substantially constant predetermined flowrate.