|Publication number||USRE40733 E1|
|Application number||US 10/359,060|
|Publication date||Jun 16, 2009|
|Filing date||Feb 5, 2003|
|Priority date||Mar 19, 1998|
|Also published as||US6190528|
|Publication number||10359060, 359060, US RE40733 E1, US RE40733E1, US-E1-RE40733, USRE40733 E1, USRE40733E1|
|Inventors||Xiang Li, Gou-Lin Luo|
|Original Assignee||Zhejiang Omex Environmental Engineering Ltd.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (33), Referenced by (2), Classifications (21), Legal Events (1)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This invention relates to novel electrodeionization apparatus adapted to transfer ions in a liquid under the influence of an electrical field. More specifically, this invention relates to a helical electrodeionization apparatus adapted to purify aqueous liquids to effect the production of high purity water.
Many techniques have been used to purify and isolate liquids or to obtain concentrated pools of specific ions or molecules from a liquid mixture, such as electrodialysis, liquid chromatography, membrane filtration and ion exchange, etc. At present, a well known process is electrodeionization (EDI). We also call it CDI (continuous deionization).
The first apparatus and method for treating liquids by electrodeionization was described by Kollsman in U.S. Pat. Nos. 2,689,826 and 2,815,320. Improved and advanced electrodeionization systems have been shown in U.S. Pat. Nos. 4,925,541, 4,931,160 and 5,316,637.
The typical structure of above-mentioned electrodeionization module is like a stacked mechanical sheet type, namely ion exchange membrane, separating wall and electrodes are processed to form a rectangle, and packed in sequence, ion exchange resin is filled up, and then is pressed to form a whole with mechanical method. It is difficult to maintain and clean the apparatus, especially one has to take apart the assembly to fill or renew the ion exchange resin. In general it needs special resin like fibre shape resin; moreover the water gathering structure of depletion compartment is more complex to process and it is easy to bring about leaking in the inner part of concentration compartments and depletion compartments.
The present invention provides a helical electrodeionization apparatus for producing highly purified water. It is a technical improvement to the above-mentioned stacked mechanical sheet type.
In one aspect, the present invention has a simple structure. It is easy to process.
In another aspect, the present invention has no special requirement for ion exchange resin. It is convenient to renew and supplement.
In yet another aspect, the present invention allows solution stream to flow smoothly when it is used. It has less of pressure drop and no leaking in operation.
This present invention provides an apparatus for producing highly purified water. The technical scheme to realize the present invention is the following:
The apparatus includes anion exchange membrane and cation exchange membrane, central pipe, main component parts, outer crust and cover.
The central pipe is a metal pipe to act as an electrode and also as water distributing and gathering pipe or water gathering pipe.
The main component parts of said apparatus which has a helical cylinder structure, with the central pipe as the helical axis. One or more than one set(s) of rolled membrane bag(s) that are formed by positioning a net-separating wall between a pair cf anion exchange membrane and cation exchange membrane is rolled up to form the cylinder structure; then twin metal strip or metal wire is wound the outside of said cylinder structure to constitute a conductive crust, so that the conductive crust can be used as another electrode.
The membrane bag(s) fits tightly to the central pipe along the axial direction so that the flow passage is communicating with the central pipe through the slotted aperture(s). Fill the ion exchange resin between the adjacent membrane bag(s) to form the flow passage for getting product water.
The structure of the present invention is much simpler, and it is suited to multiple-device series operation. Besides, daily maintenance and renewal of the resin is also more convenient than prior art.
These and other features, aspects, and advantages of the present invention will be better understood from the following drawings, description and appended claims.
Definition of the drawing's mark number:
The flow unit I 8 is an U-shape flow passage in a membrane bag structure (shown in FIG. 3): an anion exchange membrane 18 and a cation exchange membrane 19 build up a membrane bag. Three sides of said anion exchange membrane 18 and cation exchange membrane 19 are sealed by sealing edge 21, the other side is opening. An insulated net-separating wall 20 is in the membrane bag, namely between of said anion exchange membrane 18 and cation exchange membrane 19. A guide band 22 is positioned on the middle of said insulated net-separating wall 20 and kept fitting closely to the inner wall of the membrane bag to form the U-shape flow passage.
The opening side of the membrane bag fits tightly to the central pipe 11 along the axial direction, meanwhile the two terminal of the U-shape flow passage is linked up with water distributing aperture 16 and water gathering aperture 17, respectively.
One or more membrane bags are rolled up to form a cylinder structure which centers on central pipe 11 as the helical axis, according to the requirement of the product capacity.
The assembly mentioned above includes the main component parts of the present invention.
The main component parts are assembled in outer crust 5 with shell covers 2 at two terminals, outlet 1 and feed water inlet 3 are positioned at cover 2, inlet 15 and outlet 13 are positioned at the other cover 2′, anode 10 and cathode 14 which are linked up with conductive crust 6 and central pipe 11 respectively are positioned on the outer crust 5.
Insulated filler 7 is lined between outer crust 5 and conductive crust 6.
Water distributing board 4 and water gathering board 12 are lined between the shell covers 2,2′ and the cylinder structure; namely to construct the whole present invention.
In operation, pretreated water influx via the feed water inlet 3, through the flow unit II 9, and de-ionized water efflux through the outlet 13, that's the product water; concentrated water can be circulated, entering the apparatus from the inlet 15, passing through the flow unit I 8, and outgoing through the outlet 1.
To renew the ion exchange resin, remove the covers 2 and 2′, water distributing board 4 and water gathering board 12, feed water in the inlet 3 to thrust the ion exchange resin; then fill the new ion exchange resin. There is no special requirement for the ion exchange resin, even the general particle-type ion exchange resin.
According to the specification of the fed water, one apparatus of this invention can produce 1˜2 T namely 1000˜2000 liters high purity water per hour, while deionization ratio at 95%˜99%, power 0.3˜1.0 kw/h/T and utilization ratio of water 90%˜95%. For example, if the conductivity of fed water is 10 μs/cm, we can get the product water 1500 liters per hour and its conductivity is only 0.1 μs/cm. (see Table 1)
ratio of water
Said apparatus of this invention is suitable to process the pretreated water, such as the conductivity of water being lower than 500 μs/cm, especially lower than 100 μs/cm.
Said apparatus of this invention has exchangeability, namely you can change the fed water inlet for the product water outlet to meet your needs.
Said apparatus of this invention can be used in series, one stage or multi-stage.
Feed water enters the membrane bag through the opening side directly as the same time as through the ion exchange resin, then the water through the membrane bag flows into the central pipe 11 via water gathering aperture 17, and exits; the others pass through the ion exchange resin to be the product water. Therefore, only one feed water inlet is needed to be positioned at one cover of the outer crust 5. Product water outlet and concentrated water outlet are positioned at the other cover of the outer crust 5. The remaining structure is the same as mentioned above. Thus the structure is much simpler, but concentrated water cannot be used in circulation.
In short, we can find these advantages of the present invention as the following:
The present invention has been described in considerable detail with reference to certain preferred versions thereof, however other versions are possible. Therefore the spirit and scope of the appended claims should not be limited to the description of the preferred versions contained herein.
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|U.S. Classification||204/632, 204/633|
|International Classification||B01D61/46, C02F1/46, B01J47/08, C02F1/469, C02F1/42, B01D61/48|
|Cooperative Classification||C02F1/42, C02F2201/46115, C02F1/4604, B01D61/48, B01D61/46, C02F1/4695, B01D2313/086, B01D2313/146, B01J47/08|
|European Classification||C02F1/469D2, B01D61/48, B01D61/46, B01J47/08|