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Reverse osmosis system

  • US 5,207,916 A
  • Filed: 05/20/1992
  • Issued: 05/04/1993
  • Est. Priority Date: 05/20/1992
  • Status: Expired due to Fees
First Claim
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1. A reverse osmosis separation system operable to separate a feed liquid having dissolved solids into a purified liquid and concentrate, through a single unit, double-pass, reverse osmosis unit with successive banks of reverse osmosis membranes in series while using only one high pressure pump, comprising:

  • a first bank of cross flow reverse osmosis membranes;

    a high pressure pump arranged to apply excessive high pressure to feed liquid having solids therein to said first bank of reverse osmosis membranes;

    a feed supply including a feed inlet to said pump;

    said first bank of membranes having a product flow outlet for liquid that has passed through said first bank of membranes with loss of pressure, and a concentrate flow outlet for liquid that has not passed through said first bank of membranes and remains at high pressure;

    means for providing an alterative to a second pump, including;

    said high pressure pump;

    a dual chamber turbocharger downstream of said first bank of membranes and having a product flow outlet and a concentrate flow outlet, said turbo charger having a concentrate flow inlet for receiving from said first bank of membranes concentrate flow under high pressure as the dynamic liquid and discharging it out said concentrate flow outlet, and having a product flow inlet for receiving product flow under low pressure as the passive liquid and thereby elevating the pressure of said product flow to an elevated pressure when discharged from said turbocharger product flow outlet;

    a second bank of cross flow reverse osmosis membranes downstream of said turbocharger product flow outlet and having a product flow inlet for receiving said elevated pressure product flow from said turbocharger product flow outlet, said second bank having a product flow outlet and a concentrate flow outlet; and

    said concentrate flow outlet from at least one of said first and second banks of membranes being connected back to said feed supply for supplying a controlled amount of concentrate flow back to said feed inlet to thereby increase the natural osmotic pressure across said first set of membranes a controlled amount for balancing excess pressure of said feed liquid on said first bank of membranes sufficient to control net drive force and maintain proper flux rates at said first bank of membranes in a manner to avoid excess pressure causing overproduction at said first set of membranes.

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