The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 21, 2000
Filed:
Oct. 16, 1998
E-Cell Corporation, Guelph, CA;
Abstract
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.