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Recently Issued U.S. Patents relating to Electrodeionization

U.S. Patent No. 7,338,600
Issued March 4, 2008
Title: Fractional deionization process
Assignee: Aquatech International Corporation 

A liquid treatment process is described for sequential removal of ionic species of progressively decreasing ionic strength without precipitation or "scaling." An aspect of the invention includes two or more electrodeionization operations within one or more electrodeionization stacks. The first electrodeionization operation is performed at a voltage calculated to remove strongly ionized species such as calcium and magnesium from the feed water without scaling. The product of the first electrodeionization operation is then subjected to a second electrodeionization operation. The second electrodeionization operation is performed at a voltage the same as the first electrodeionization operation, and is designed to remove more weakly ionized species such as silica and carbon dioxide, preventing scaling. More than two successive electrodeionization operations may be performed if desired. Multiple electrodeionization operations may occur in a single electrodeionization stack or in multiple electrodeionization stacks.

U.S. Patent No. 7,329,358
Issued: February 12, 2008
Title: Fractional deionization process
Assignee: Siemens Water Technologies

A system and process for treating water are described. Water may be purified by passing feed water through an electrochemical deionization device. The water may be suitable for cooking, washing, and beverage production. 

U.S. Patent No. 7,326,325 
Issued: February 5, 2008 
Title: Apparatus and method for connecting water treatment devices 
Assignee: Siemens Water Technologies

A method and apparatus for connecting water treatment devices is provided. Connecting brackets may allow for a multiple configurations of water treatment devices and can simplify the building of water treatment systems.

U.S. Patent No. 7,306,934 
Issued: December 11, 2007 
Title: Porous solid ion exchange wafer for immobilizing biomolecules 
Assignee: UChicago Argonne, LLC 

A porous solid ion exchange wafer having a combination of a biomolecule capture-resin and an ion-exchange resin forming a charged capture resin within said wafer. Also disclosed is a porous solid ion exchange wafer having a combination of a biomolecule capture-resin and an ion-exchange resin forming a charged capture resin within said wafer containing a biomolecule with a tag. A separate bioreactor is also disclosed incorporating the wafer described above.

U.S. Patent No. 7,306,709 
Issued: December 11, 2007 
Title: Spiral electrodeionization device with flow distribution profiling 
Assignee: GE Osmonics, Inc. (Minnetonka, MN)

EDI apparatus for demineralizing a liquid flow is assembled in a housing having a cylindrical shape, and includes two metal electrodes, and one or more leafs, each leaf comprising a pair of selectively ion-permeable membranes arranged parallel to each other and spaced apart by spacing elements that allow liquid to flow in the interstitial space between membranes, thus forming an arrangement of dilute and concentrate cells in a desired flow configuration. Spacing elements between membranes, as well as between leaves, can be formed of inert polymer material, ion exchange beads, ion exchange fibers, a combination of two or more these elements, or a porous media incorporating one or more of such elements as an intrinsic part. An inner or central electrode and an outer or perimeter electrode establish a generally uniform and radially-oriented electrical or ionic current between the inner and the outer electrodes, across the helical flow spaces defined by the membrane/spacer windings. One or both electrodes may include a pocket, and the adjacent flow cells lie parallel to the electrode and free of shadowing and field inhomogeneity around a full circumference of the electrode. Flow paths within the helical cells are defined by barrier seals, which may form a path-lengthening maze, while unfilled cell regions may disperse or collect flow within a cell and define pressure gradients promote directional flows. Impermeable barriers between membranes further prevent the feed and concentrate flows from mixing. In various embodiments, seals along or between portions of the flow path may define a multi-stage device, may define separate feed and/or concentrate flows for different stages, and/or may direct the feed and concentrate flows along preferred directions which may be co-current, counter-current or cross-current with respect to each other within the apparatus. 

U.S. Patent No. 7,279,083 
Issued: October 9, 2007 
Assignee: VWS (UK) Ltd
Title: Electrodeionisation apparatus 

An electrodeionisation apparatus comprising, successively: means defining an anode chamber, means defining one or more anion exchange chambers, means defining one or more mixed exchange chambers, means defining one or more cation exchange chambers, and means defining a cathode chamber, the anion, mixed and cation exchange chambers providing a flow path for water to be purified, is described. The present invention incorporates advantages of both separate resin bed and mixed resin bed technology.

U.S. Patent No. 7,264,737 
Issued: September 4, 2007 
Title: Control of water treatment system with low level boron detection 
Assignee: Ionics, Incorporated

A water treatment system and method including a membrane-based boron removal unit includes a boron analyzer for detecting the concentration of boron in a treatment stream. The boron removal unit can be a reverse osmosis (RO) or electrodeionization (EDI) treatment unit. A controller responds to the detected boron concentration to control an operation of the RO or EDI units. In an EDI system, the controller may adjust current or voltage supplied to match current to changes in ionic load and maintain a portion of the dilute cell in a substantially regenerated state. In an RO system, the controller may control the high pressure side flow rate, the brine blowdown rate, the product water permeation rate, pH, or feed rate of chemicals in response to the detected boron concentration value.

U.S. Patent No. 7,261,802 
Issued: August 28, 2007 
Title: EDI module with stabilizing DC current 
Assignee: Zhejiang Omex Enviromental Engineering Ltd.

A stabilizing DC current interface for an electro-deionization (EDI) water purifying module. Each EDI module comprises anionic/cationic membranes, a center pipe, nets/spacers in concentrate/dilute water chambers and an anode and cathode for coupling to the stabilizing DC current interface. Because a stabilized DC current is provided by the interface, the power to each EDI module is not influenced by water temperature, flow rate, water quality in the module, thereby providing a stabilized quality product water while saving energy. A plurality of EDI modules can be operated in electrical series using a DC current interface resulting in reduced DC power consumption. 

U.S. Patent No. 7,247,225 
Issued: July 24, 2007 
Title: Electrodeionization apparatus 
Assignee: Kurita Water Industries Ltd. 

An electrodeionization apparatus is provided, in which enough electric current flows even when voltage applied between the electrodes is low, thereby sufficiently performing deionization. A single first cation exchange membrane, a single anion exchange membrane, a single second cation exchange membrane are arranged between a cathode and an anode so that a concentration-cathode compartment, a desalting compartment, a concentrating compartment, and an anode compartment are formed, in this order, between the cathode and the anode. The concentration-cathode compartment and the anode compartment are filled with a cation exchange resin, respectively. The desalting compartment is filled with a mixture of the cation exchange resin and an anion exchange resin. Fed into the anode compartment is raw water or deionized water. Water from the anode compartment is sent to the concentrating compartment and the concentration-cathode compartment sequentially.

U.S. Patent No. 7,201,832 
Issued: April 10, 2007 
Title: Electrodeionization deionized water producing apparatus 
Assignee: Organo Corporation

In the electrodeionization deionized water producing apparatus, water is passed through a deionizing chamber(s) packed with an organic porous ion exchange material having a three-dimensional network structure to remove ionic impurities in the water, thereby producing deionized water. At the same time, a DC electric field is applied to the deionizing chamber(s) to discharge ionic impurities adsorbed on the organic porous ion exchange material outside the system, wherein the DC electric field is applied so that the ions to be discharged may electrophoretically move in the direction reverse to the flow of water through the organic porous ion exchange material.

U.S. Patent No. 7,173,066 
Issued: February 6, 2007 
Title: Ion exchanger 
Assignee: Organo Corporation

A porous ion exchanger includes an open cell structure including interconnected macropores and mesopores whose average diameter is in a range of 1 to 1000 .mu.m existing on walls of the macropores. Moreover, a total pore volume is in a range of 1 to 50 ml/g, ion exchange groups are uniformly distributed, and an ion exchange capacity is not less than 0.5 mg equivalent/g of dry porous ion exchanger. The porous ion exchanger can be used as an ion exchanger filled into a deionization module of an electrodeionization water purification device, solid acid catalyst, adsorbent, and filler for chromatography.

U.S. Patent No. 7,163,964 
Issued: January 16, 2007 
Title: Method for preparing an ion exchange media 
Assignee: Aquatech International Corporation 

This invention presents an ion exchange media including a plurality of cation exchange zones and anion exchange zones in flow paths that are contained in a substantially nonporous resin transport framework. During electrodeionization and other potential applications the ion exchange media of the invention prevents unfavorable water splitting at resin-membrane interfaces and encourages water splitting at resin--resin interfaces where the water splitting may be constructively used to regenerate the resin.

U.S. Patent No. 7,147,785 
Issued: December 12, 2006 
Title: Electrodeionization device and methods of use 
Assignee: USFilter Corporation 

The present invention generally relates to purification systems, and to sanitization and/or sealing of the purification system. The purification system includes an electrodeionization device which can comprise one or a plurality of stages. The electrodeionization device can be constructed with a resilient sealing member forming a water-tight seal between rigid thermally and dimensionally stable compartment spacers. The construction of the electrodeionization device may allow cycling of hot water and/or other liquids, which, in some cases, can improve efficiency and performance of the electrodeionization device. Moreover, the cycling of hot water and/or other liquids may be used to sanitize the electrodeionization device to at least a pharmaceutically acceptable condition and, preferably, in certain instances, to meet at least minimum requirements according to U.S. Pharmacopoeia guidelines by inactivating any microorganisms present within the electrodeionization device.

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