Patent ID: 6042701
Filing Date: 2000-03-28
Classification: B01D,C02F,Y02A

Abstract:
A system for desalting a feed water source containing anions and cations from salt dissolved in said feed water, said system comprising:a membrane stack comprising of at least one electrical stage, said electrical stage comprising an anode electrode of positive polarity, a cathode electrode of negative polarity, and at least one cation transfer membrane and at least one anion transfer membrane, said membranes being disposed between said electrodes such that when feed water is fed between said electrodes, cations in said feed water pass through said cathode transfer membrane to said cathode electrode while being blocked from passing through said anion transfer membrane, and anions in said feed water pass through said anion transfer membrane to said anode electrode while being blocked from passing through said cation transfer membrane, such that the feed water is separated into a desalted product water portion and a remaining portion;polarity reversing means for temporarily reversing the polarities of said electrodes so as to remove salts that accumulate on said cation transfer membrane and salts that accumulate on said anion transfer membrane;an electrically controlled feed pump for pumping feed water through said membrane stack;an electrically controlled flow control means for controlling the flow path of said product water portion and said remaining portion of said feed water after said portions exit from said membrane stack, anda direct current power source for supplying direct current to said electrodes, said polarity reversing means, said feed pump and said flow control means,said direct current power source producing an output voltage, and said system further comprising a first DC-DC voltage converter, connected to said direct current power source and to said feed pump, for supplying a voltage to said feed pump related to the output voltage produced by said direct current power source,adjustable means for manually adjusting said voltage supplied by said first converter to said feed pump so as to adjust the flow rate of feed water pumped to said membrane stack by said feed pump, said adjustable means comprising a potentiometer and a plurality of resistors connected to prevent linear power losses,a circuit board including switching controls for said system and microcontroller unit including a programmable microprocessor for transmitting signals to, and receiving signals from, said circuit board to control operation of said system, anda second DC-DC voltage converter, connected to said direct current power source, for supplying power to said circuit board and said microcontroller unit,said polarity reversing means comprising a relay for each electrical stage in said membrane stack, and said system further comprising a third DC-DC voltage converter connected to said direct current source, and including an output for each electrical stage and manual adjustment means for manually adjusting power supplied by said third converter, said manual adjustment means being connected to each said electrical stage through a said relay, and said manual adjustment means comprising a potentiometer and a plurality of resistors connected to prevent linear power losses.