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AssigneeE-Cell Corporation
InventorsDavid Florian Tessier, Robert Glegg, John H. Barber
Estimating the term…
A method and apparatus is provided for inhibiting scaling in an electrodeionization system and, more particularly, for increasing tolerance to hardness in the feed water to an electrodeionization unit by inhibiting precipitation of scale-forming metallic cations contained in the feed water and thereby increasing efficiencies of the electrodeionization system. Water to be purified is passed through an electrodeionization unit in which the flow in the diluting compartment is countercurrent to the flow in the concentrating compartment. This is to impede the migration of scale-forming metallic cations from the diluting compartment, through the cation exchange membrane, into the concentrating compartment and towards the concentrating compartment side of the anion exchange membrane, thereby preventing scale formation on the anion exchange membrane. The electrodeionization unit may be further modified by dividing the concentrating compartments into first and second compartments by a porous diaphragm or ion-conducting membrane. The porous diaphragm or ion-conducting membrane effectively eliminates convective transport of scale-forming metallic cations from the cation exchange membrane side of the concentrating compartment to the anion exchange membrane side of the concentrating compartment, thereby inhibiting scale formation on the anion exchange membrane.
A method for inhibiting formation of scale in an electrodeionization unit for deionizing water having an anode compartment at one end of the unit, a cathode compartment at the opposite end of the unit, and a plurality of diluting compartments alternating with concentrating compartments positioned between the said anode and cathode compartments, comprising the steps of:
An electrodeionization unit for deionizing water having an anode compartment at one end of the unit, a cathode compartment at the opposite end of the unit, and a plurality of diluting compartments alternating with concentrating compartments between the said anode and cathode compartments, each of said diluting and concentrating compartments defined by anion and cation exchange membranes, at least one of said concentrating compartments further comprising a porous diaphragm or ion-conducting membrane for dividing said concentrating compartment into first and second compartments such that said first compartment is defined by an anion exchange membrane and said porous diaphragm or ion-conducting membrane and said second compartment is defined by said cation exchange membrane and said porous diaphragm or ion-conducting membrane wherein liquid in said first compartment is prevented from mixing with liquid in said second compartment and wherein ions can migrate between said first and second compartments through said porous diaphragm or ion-conducting membrane.
A method for inhibiting formation of scale in an electrodeionization unit for deionizing water having an anode compartment at one end of the unit, a cathode compartment at the opposite end of the unit, and a plurality of diluting compartments alternating with concentrating compartments between the said anode and cathode compartments, each of said diluting and concentrating compartments defined by anion and cation exchange membranes, at least one of said concentrating compartments further comprising a porous diaphragm or ion-conducting membrane for dividing said concentrating compartment into first and second compartments such that said first compartment is defined by an anion exchange membrane and said porous diaphragm or ion-conducting membrane and said second compartment is defined by said cation exchange membrane and said porous diaphragm or ion-conducting membrane wherein liquid in said first compartment is prevented from mixing with liquid in said second compartment and wherein ions can migrate between said first and second compartments through said porous diaphragm or ion-conducting membrane, comprising the steps of:
A method for inhibiting formation of scale in an electrodeionization unit for deionizing water having an anode compartment at one end of the unit, a cathode compartment at the opposite end of the unit, and a plurality of diluting compartments alternating with concentrating compartments positioned between the said anode and cathode compartments, comprising the steps of:
Dependencies are inferred from the claim text.