Helical electrodeionization apparatus

Abstract

A helical electrodeionization apparatus is adapted to purify aqueous liquids to effect the production of high purity water. An insulated net-separating wall is positioned between a pair of anion and cation exchange membranes to form a special membrane bag type flow unit I, each flow unit I is linked up with a group of slots on the side walls of central pipe, and is rolled up to form cylinder structure which centers on central pipe as the helical axis, a conductive crust is formed by winding metal strip or wire outside the cylinder. Ion exchange resin is filled up between the adjacent membrane bags to form flow unit II. The present invention has less pressure drop and needs less power, and is suited to multiple-device series operation. Preferably, daily maintenance and renewal of the resin is convenient, and production cost is lower.

1. A helical electrodeionization apparatus which comprises an anion exchange membrane ( 18 ) and a cation exchange membrane ( 19 ), a central pipe ( 11 ), a plurality of main component parts, an outer crust ( 5 ) and covers( 2 , 2 ′), wherein:
 said central pipe ( 11 ) is a metal pipe that acts as an electrode and also as a water distributing or gathering pipe;  
 said main component parts of said apparatus, which have a helical cylinder structure with said central pipe ( 11 ) as the helical axis, further comprising: 
 i. at least one set of rolled membrane bags that are formed by positioning a net-separating wall ( 20 ) between an anion exchange membrane ( 18 ) and a cation exchange membrane ( 19 ),  
 ii. metal strip or metal wire twined round the outside of said cylinder structure which forms a conductive crust, said conductive crust being used as another electrode;  
 
 a first flow unit ( 8 ) of said main component parts, including the flow passage in said membrane bag being fitted tightly and communicating with said central pipe ( 11 ) along the axial direction; and  
 a second flow unit ( 9 ) of said main component parts, including the flow passage between said adjacent membrane bags being formed by filling ion exchange resin.  
 
     
     
       2. The apparatus of  claim 1 , wherein said central pipe ( 11 ) is blocked in the middle, the upper half part operating as a water gathering pipe which has water gathering aperture ( 17 ) slotted in a side wall; the lower half part operating as a water distributing pipe which has water distributing aperture ( 16 ) slotted in the side wall; each set of water distributing and gathering aperture ( 16 , 17 ) being slotted on the same axial line. 
     
     
       3. The apparatus of  claim 1 , wherein said first flow unit ( 8 ) has a U-shape flow passage which is comprised of an anion exchange membrane ( 18 ) and a cation exchange membrane ( 19 ), three sides of said anion exchange membrane ( 18 ) and cation exchange membrane ( 19 ) sealed by sealing edge ( 21 ) to form a membrane bag structure, the other side opening; an insulated net-separating wall ( 20 ) being in the membrane bag, between said anion exchange membrane ( 18 ) and said cation exchange membrane ( 19 ), a guide band ( 22 ) positioned on the middle of said insulated net-separating wall ( 20 ) and kept fitting closely to the inner wall of said membrane bag to form the U-shape flow passage; the opening side of said membrane bag being fitted tightly to the central pipe ( 11 ) along the axial direction, meanwhile the two terminal of the U-shape flow passage linked up with the water distributing aperture ( 16 ) and water gathering aperture ( 17 ), respectively. 
     
     
       4. The apparatus of  claim 1 , wherein said first flow unit ( 8 ) can also be the flow passage in such a membrane bag: two sides of anion exchange membrane ( 18 ) and cation exchange membrane ( 19 ) sealed by sealing edge, the third side opening, whole or partial, as the entrance of concentrated water, the last side of the membrane bag being fitted tightly to the central pipe ( 11 ) along the axial direction and linked with water gathering aperture ( 17 ); water entering the membrane bag through the opening side directly, flowing into the central pipe ( 11 ) via water gathering aperture ( 17 ), and exiting. 
     
     
       5. The apparatus of  claim 1 , wherein the conductive crust ( 6 ) is wound with metal strip or metal wire. 
     
     
       6. A helical electrodeionization apparatus comprising: an anion exchange membrane; a cation exchange membrane; an axially extending conduit acting as a water distributing or gathering member; a first electrode; at least one rolled membrane bag formed by positioning an interface between the anion exchange membrane and the cation exchange membrane; a metal member extending about the outside of and separate of said at least one membrane bag to form a second electrode; a first flow unit including a flow passage in said membrane bag and communicating with said conduit along the axial direction; a second flow unit including a flow passage adjacent said at least one membrane bag; and a housing for the foregoing components. 
     
     
       7. The apparatus of  claim 6  wherein the interface is a net separating wall. 
     
     
       8. The apparatus of  claim 6 , wherein said second electrode comprises a metal strip or metal wire forming a conductive crust. 
     
     
       9. The apparatus of  claim 6 , wherein said first flow unit is arranged to be a flow passage in said at least one membrane bag, said first flow unit includes an anion exchange membrane and a cation exchange membrane, said anion exchange membrane and cation exchange membrane being sealed by a sealing edge to form said membrane bag, said membrane bag including an insulated net- separating wall, an inner wall, an exposed side and an opening side, said insulated net - separating wall positioned in the membrane bag between said anion exchange membrane and said cation exchange membrane, said opening side being fitted tightly to said axially extending conduit along an axial direction, said exposed side being open for influx of concentrated water which is adapted to follow said flow passage into said axially extending conduit along an axial direction via said water distributing or gathering member.   
     
     
       10. The apparatus of  claim 6 , wherein said second electrode is wound with metal strip or metal wire. 
     
     
       11. The apparatus of  claim 6 , wherein said housing comprising an outer crust having a first end and a second end, said housing further comprising a first cover removably coupled to said first end and a second cover removably coupled to said second end. 
     
     
       12. The apparatus of  claim 6 , further comprising a cathode linked with said first electrode and an anode linked with said second electrode. 
     
     
       13. The apparatus of  claim 6  wherein said at least one rolled membrane bag is at least one set of rolled membrane bags formed by positioning an interface between the anion exchange membrane and the cation exchange membrane. 
     
     
       14. A helical electrodeionization apparatus comprising: an anion exchange membrane; a cation exchange membrane; an axially extending conduit acting as a water distributing or gathering member; a first electrode; at least one rolled membrane bag formed by positioning an interface between the anion exchange membrane and the cation exchange membrane; a metal member extending about the outside of said at least one membrane bag to form a second electrode; a first flow unit including a flow passage in said membrane bag and communicating with said conduit along the axial direction; a second flow unit filled with an ion exchange resin and including a flow passage adjacent said at least one membrane bag; and a housing for the foregoing components, wherein said first electrode is said axially extending conduit. 
     
     
       15. The apparatus of  claim 14  wherein said axially extending conduit is a metal pipe centrally extending within said housing. 
     
     
       16. A helical electrodeionization apparatus comprising: an anion exchange membrane; a cation exchange membrane; an axially extending conduit acting as a water distributing or gathering member, a first electrode; at least one rolled membrane bag formed by positioning an interface between the anion exchange membrane and the cation exchange membrane; a metal member extending about the outside of said at least one membrane bag to form a second electrode; a first flow unit including a flow passage in said membrane bag and communicating with said conduit along the axial direction; a second flow unit filled with an ion exchange resin and including a flow passage adjacent said at least one membrane bag; and a housing for the foregoing components, wherein said water distributing or gathering member is a water distributing member and a water gathering member. 
     
     
       17. The apparatus of  claim 16 , wherein said axially extending conduit comprises a slotted side wall and a blocking member defining an upper part and a lower part, wherein said upper part is the water gathering member and said lower part is the water distributing member, said water gathering member having a water gathering aperture in said slotted wall and said water distributing member having a water distributing aperture, said water gathering aperture and said water distributing member being aligned on the same axis. 
     
     
       18. The apparatus of  claim 16 , wherein said first flow unit includes a U- shape flow passage comprised of said anion exchange membrane and said cation exchange membrane, said anion exchange membrane and cation exchange membrane being sealed by a sealing edge to form said membrane bag, said membrane bag including a guide band, an inner wall, and an opening side, said guide band positioned substantially along the middle of said membrane bag and kept fitting close to said inner wall to form said U - shaped flow passage, said opening side fitted tightly to said axially extending conduit along an axial direction, said opening side linked with said water distributing member and said water gathering member.   
     
     
       19. A helical electrodeionization apparatus comprising: an anion exchange membrane; a cation exchange membrane; a central pipe acting as a water distributing or gathering member; a first electrode; at least one rolled membrane bag formed by positioning an interface between said anion exchange membrane and said cation exchange membrane; a metal member extending about the outside of and separate of said at least one membrane bag to form a second electrode; a first flow unit including a flow passage in said membrane bag and communicating; with said central pipe along the axial direction; a second flow unit including a flow passage adjacent said at least one membrane bag; and a housing for the foregoing components. 
     
     
       20. The apparatus of  claim 19  wherein said interface is a net separating wall. 
     
     
       21. The apparatus of  claim 19 , wherein said first electrode is said central pipe. 
     
     
       22. The apparatus of  claim 19 , wherein said water distributing or gathering member is a water distributing member and a water gathering member. 
     
     
       23. An electrodeionization apparatus comprising: an anion exchange membrane; a cation exchange membrane; an axially extending conduit acting as a water distributing or gathering member; a first electrode; at least one rolled membrane bag formed by positioning an interface between the anion exchange membrane and the cation exchange membrane; a metal membrane extending about the outside of said at least one membrane bag to form a second electrode; a first flow unit including a U- shaped first flow passage in said membrane bag and communicating with said conduit along the axial direction; a second flow unit including a second flow passage adjacent said at least one membrane bag; and a housing for the foregoing components.   
     
     
       24. The apparatus of  claim 23 , wherein said U- shape flow passage is formed by said membrane bag, said membrane bag including a guide band, an inner wall, and an opening side, said guide band positioned substantially along the middle of said membrane bag and kept fitting close to said inner wall to form said U - shaped flow passage, said opening side fitted tightly to said axially extending conduit along the axial direction, said opening side linked with said water distributing member or said water gathering member.   
     
     
       25. An electrodeionization apparatus comprising: an anion exchange membrane; a cation exchange membrane; an axially extending conduit acting as a water distributing or gathering member; a first electrode; at least one rolled membrane bag formed by positioning an interface between the anion exchange membrane and the cation exchange membrane; a metal member extending about the outside of said at least one membrane bag to form a second electrode; a first flow unit including a flow passage in said membrane bag and communicating with said conduit along the axial direction; a second flow unit including a flow passage adjacent said at least one membrane bag; a radially extending water gathering unit communicating with said second flow unit along the radial direction; and a housing for the foregoing components. 
     
     
       26. The apparatus of  claim 25 , wherein said water gathering unit is a water gathering board. 
     
     
       27. An electrodeionization apparatus comprising: an anion exchange membrane; a cation exchange membrane; an axially extending conduit acting as a water distributing or gathering member; a first electrode; at least one rolled membrane bag formed by positioning an interface between the anion exchange membrane and the cation exchange membrane, said anion exchange membrane and cation exchange membrane being sealed by a sealing edge opposite said conduit to define said membrane bag; a metal member extending about the outside of said at least one membrane bag to form a second electrode; a first flow unit including a first flow passage in said membrane bag and communicating with said conduit along the axial direction; a second flow unit including a second flow passage adjacent said at least one membrane bag; a water gathering unit separate from said sealing unit and communicating with said second flow unit; and a housing for the foregoing components. 
     
     
       28. The apparatus of  claim 27 , wherein said water gathering unit extends radially from said axially extending conduit. 
     
     
       29. An electrodeionization apparatus comprising: an anion exchange membrane; a cation exchange membrane; an axially extending conduit acting as a water distributing or gathering member; a first electrode; at least one rolled membrane bag formed by positioning an interface between the anion exchange membrane and the cation exchange membrane; a metal member extending about the outside of said at least one membrane bag to form a second electrode; a first flow unit including a flow passage in said membrane bag and communicating with said conduit along the axial direction; a second flow unit including a flow passage adjacent said at least one membrane bag; a radially extending water distributing unit communicating with said second flow unit along the radial direction; and a housing for the foregoing components. 
     
     
       30. The apparatus of  claim 29 , wherein said water gathering unit is a water gathering board. 
     
     
       31. An electrodeionization apparatus comprising: an anion exchange membrane; a cation exchange membrane; an axially extending conduit acting as a water distributing or gathering member; a first electrode; at least one rolled membrane bag formed by positioning an interface between the anion exchange membrane and the cation exchange membrane; a metal member extending about the outside of said at least one membrane bag to form a second electrode; a first flow unit communicating with said conduit along the axial direction and including a first flow passage for circulating a first fluid in said at least one membrane bag towards said axially extending conduit; a second flow unit adjacent said at least one membrane bag and including a second flow passage for passing a second fluid in a direction substantially along the axial direction; and a housing for the foregoing components. 
     
     
       32. The apparatus of  claim 31 , wherein said first flow passage circulates the first fluid in said membrane bag both away from said axially extending conduit and towards said axially extending conduit.