Water purification system and methods, and module for the system

A method of purifying water comprising the steps of:

• pressurizing the water to be purified;
• directing a pressurized flow of said water onto at least one selective permeability membrane to divide the flow of pressurized water into a permeate flow and a retentate flow;
• electrodeionizing the permeate flow to produce a flow of purified water consisting of the electrodeionized permeate flow;
• reducing the flowrate of the retentate flow;
• and maintaining a substantially constant predetermined pressure on the selective permeability membrane(s);
• which method is characterized in that it further includes a step of maintaining a substantially constant predetermined permeate flowrate with a 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 the substantially constant predetermined value.

A water purification system comprising:

• a pump (IO) 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 (ii) 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 and is configured for maintaining a substantially constant predetermined permeate flowrate in the event of an upstream pressure rise, said flowrate regulator comprising a motorized flowrate regulation valve operated by an automatic controller.

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 (ii) 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 and is configured for maintaining a substantially constant predetermined permeate flowrate in the event of an upstream pressure rise, wherein said restriction comprises a plate in which a fixed orifice is formed.