Electrode structures for electric treatment of fluids and filters using same

• US 3,980,541 A
• Filed: 05/06/1971
• Issued: 09/14/1976
• Est. Priority Date: 06/05/1967
• Status: Expired due to Term

• Current Assignee: Harry E. Aine
• Original Assignee: Harry E. Aine
• Inventors: Aine, Harry E.
• Primary Examiner(s): Tufariello, T. M.
• Application Number:
  US05/140,937
• Time in Patent Office: 1,958 Days
• Field of Search: 204/280, 204/290 R, 204/302, 204/186, 204/188, 204/284
• US Class Current: 204/554
• CPC Class Codes: B01D 17/06 Separation of liquids from each other by electricity
• CPC Class Codes: B01D 35/06 Filters making use of electricity or magnetism ultrafiltration, microfiltration B01D61/14; electrodialysis, electro-osmosis B01D61/42; devices comprising filters and magnetic separators B03C1/30
• CPC Class Codes: B03C 2201/02 Electrostatic separation of liquids from liquids
• CPC Class Codes: B03C 5/024 using high-gradient differential dielectric separation, i.e. using a dielectric matrix polarised by an external field

Abstract

Composite electrode structures are disclosed employing mutually opposed electrodes spaced apart to define a fluid treatment region through which a fluid is passed for treatment by an electric field established between the electrodes. Resistive electrodes serve to localize the effect of electrical shorts between the electrodes. Refractory electrodes and insulators permit operation in high temperature environments. Non-uniform sheet and/or filamentary electrodes are disclosed for producing a substantial non-uniformity in the electric field within the treatment region for producing forces on particles having no net charge. A floating electrode between driven electrodes allows formation of an induced electric field in the treatment region while reducing the possibility of electrical shorts. Paper electrodes and paper insulators permit fabrication of an inexpensive electrode structure. Moisture is removed from the treated fluid by loading either or both the insulator and electric structures with a hygroscopic electrolyte and passing a current through the electrolyte to convert the moisture into elemental oxygen and hydrogen.

Claims

1. In an electrical fluid treating apparatus for treating non-electrolytic fluids, first and second electrode means spaced apart to define at least a portion of a composite electrode structure having an electrical treatment region through which a stream of non-electrolytic fluid is to pass for treatment, insulator means for insulating said first electrode from said second electrode to permit an electrical field to be established between said electrodes in said treatment region, resistive means incorporated in at least one of said electrode means in such a manner that, in the presence of an electrical short between said electrodes through the non-electrolytic fluid to be treated in said treatment region, said resistive means drops the applied potential across said resistive means in a localized portion of said resistive electrode structure such that less than one-tenth of said treatment region is effectively shorted by said electrical short.

2. The apparatus of claim 1 including, contactor electrode means for contacting opposite sides of said composite electrode structure such that a short between said electrodes causes the shorting current to flow from one contactor electrode means to the other contactor electrode means through said resistive electrode from one side edge of the composite electrode structure to the opposing side edge of said composite electrode structure.

3. The apparatus of claim 1 wherein each of said first and second electrodes is sheet shaped and disposed with their broad sides in mutually opposed relation.

4. The apparatus of claim 3 including, contactor grid means disposed for making electrical contact to a side edge of at least one of said sheet shaped electrodes and being pervious to fluid flow therethrough into said electrical treatment region between the mutually opposed broad sides of said first and second electrodes.

5. The apparatus of claim 3 wherein said sheet shaped electrodes each comprise a web of insulative material coated with an electrically conductive material.

6. The apparatus of claim 3 wherein said sheet shaped electrodes are made of conductive paper.

7. The apparatus of claim 1 wherein said first and second electrodes are made of refractory material.

8. The apparatus of claim 7 wherein said refractory material is selected from the class consisting of ceramic, asbestos, carbon, glass and quartz.

9. The apparatus of claim 3 wherein each of said sheet shape first and second electrodes is perforated with a multitude of perforations to facilitate fluid flow therethrough.

10. The apparatus of claim 3 wherein at least one of said sheet shaped first and second electrodes is corrugated with the mean peak-to-peak depth of said corrugations being greater than one-fourth of the mean spacing between said first and second sheet electrodes, and each corrugations being arranged relative to the opposed electrode surface such as to produce a substantial non-uniform electric field between opposed electrode surfaces.

11. The apparatus of claim 7 wherein said refractory material includes a carbon impregnated ceramic.

12. The apparatus of claim 3 including a strip of electrically conductive material disposed on at least one of said sheet shaped electrodes to render said strip portion of said electrode more electrically conductive than the adjacent regions of said sheet shaped electrode to facilitate making of electrical contact to said sheet shaped electrode.

13. The apparatus of claim 12 wherein said strip of electrically conductive material is disposed along at least one marginal side edge of said sheet shaped electrode.

14. The apparatus of claim 12 wherein said strip of electrically conductive material comprises a strip of carbon.

15. The apparatus of claim 9 wherein said perforations have a mean minor lateral dimension in the plane of said sheet electrode which is greater than one-fourth of the mean spacing between the opposed sheet electrodes.

16. The apparatus of claim 1 wherein said insulator means includes a sheet of insulative material interposed between said first and second sheet electrodes.

17. The apparatus of claim 16 wherein said sheet of insulative material is perforated.

18. The apparatus of claim 3 wherein said insulator means includes a fibrous web of insulative material interposed in the space between said first and second sheet electrodes.

19. The apparatus of claim 16 wherein said sheet of insulative material includes a sheet of paper.

20. The apparatus of claim 16 wherein said sheet of insulative material is refractory and selected from the class consisting of ceramic, glass, asbestos, and quartz.

21. The apparatus of claim 3 wherein said sheet shaped electrodes each comprise a web of insulative material coated with a conductive material selected from the class consisting of metallic salts, conductive polymers, carbon, and metals.

22. The apparatus of claim 1 including, third floating electrode means interposed between said first and second electrode means in spaced relation therefrom to define at least one fluid passageway therebetween, said third electrode means being disposed in electrically insulative and in change inducing relationship with said first and second electrode means such that an electrical potential applied across said first and second electrode means induces a charge distribution in said floating electrode means of opposite polarity to the charge distribution produced in said first and second electrode means in response to the applied potential, whereby an electrical treating field is produced in said fluid passageway between said third floating electrode means and at least one of said first and second electrode means.

23. The apparatus of claim 22 wherein said floating electrode means includes a plurality of floating electrode portions electrically isolated from each other.

24. The apparatus of claim 22 including second resistive means incorporated in said floating electrode means in such a manner that an electrical short between said floating electrode means and one of said other electrode means in said treatment region serves to drop the applied potential across said second resistive means such that less than one-tenth of said treatment region is effectively shorted by said short.

25. The apparatus of claim 22 wherein said first, second and third electrodes are made of an electrically conductive fibrous web.

41. The apparatus of claim 1 wherein, said first and second electrode means comprise filamentary conductive electrodes intertwined to define a composite electrode structure having an electrical treating region defined by the space between said intertwined electrode means and through which a stream of fluid is to pass for electrical treatment.

42. The apparatus of claim 41 wherein said first and second filamentary electrode means are twisted together.

26. In an electrical fluid treating apparatus for treating non-electrolytic fluids, means forming first and second electrodes spaced apart to permit a stream of non-electrolytic fluid to pass therebetween, means forming an insulative structure disposed in the space between said electrodes to permit a voltage to be established between said electrodes, the improvement wherein, said first and second electrodes are sheets of conductive paper interleaved with said insulative structure to form a composite electrode structure.

27. The apparatus of claim 26 wherein said first paper sheet conductive electrode includes a sheet of aluminum foil supported upon a paper web.

28. In an electrofilter apparatus for removing particulate contaminates from an electrically resistive fluid, first and second sheet shaped electrodes spaced apart with their broad sides in mutually opposed relation to define a composite electrode structure having an electrical filtering region through which a stream of fluid is to pass for electric filter treatment, insulator means interposed in the space between said mutually opposed broad sides of said electrodes for insulatively supporting said first and second sheet electrodes from each other in spaced relation and to permit an electric field to be established between said electrodes in said treatment region, at least one of said sheet shaped electrodes being electrically non-uniform such as to produce a substantial non-uniformity in the electric field intensity established in said filter treatment region between said electrodes.

29. The apparatus of claim 28 wherein said electrical non-uniformity of said electrode comprises a substantial variation in the spacing between the mutually opposed broad sides of said first and second electrodes, whereby a substantial non-uniformity in the electric field intensity is produced in the electric filter treatment region.

30. The apparatus of claim 36 wherein said variation in the spacing between said first and second electrodes comprises a corrugation of said electrically non-uniform electrode with the peak-to-peak amplitude of the corrugation of said sheet electrode being greater than one-quarter of the mean spacing between said first and second electrodes.

31. The apparatus of claim 28 wherein said non-uniformity of said electrode comprises a repetitive discontinuity of said electrode structure in the plane of the sheet electrode such as to produce a substantial non-uniformity in the electric field intensity in the electric filter treatment region.

32. The apparatus of claim 31 wherein said discontinuity of said electrode structure comprises a periodic discontinuous pattern of said electrode, said periodic pattern having mean lateral dimensions in the plane of said sheet electrode sufficiently large such as to produce a substantial non-uniformity of the electric field in the electric treatment region between said sheet electrodes.

33. The apparatus of claim 28 wherein said insulative means includes a web of insulative material.

34. The apparatus of claim 33 wherein said web of insulative material includes a sheet of insulative paper.

35. The apparatus of claim 28 wherein said insulator means includes a sheet of insulative material interposed between said first and second electrode with each of its broad sides facing a broad side of said electrodes.

36. The apparatus of claim 35 wherein said insulator means includes a coating of insulative material coating one of said sheet members.

37. The apparatus of claim 28 wherein said non-uniform electrode includes a porous web structure at the surface thereof adjacent the electric filtering region for trapping particulate contaminants forced toward said non-uniform electrode.

38. The apparatus of claim 28 wherein said non-uniform electrode comprises an electrically conductive porous fibrous web.

39. The apparatus of claim 28 wherein said non-uniform electrode includes a sheet of conductive paper.

40. In an electrofilter apparatus for removing particulate contaminates from an electrically resistive fluid, first and second sheet shaped electrodes disposed in spaced apart relation with their broad sides in mutually opposed relation to define a composite electrode structure having an electric filtering region through which a stream of fluid is to pass for electric filter treatment, insulator means for insulatively supporting said first and second sheet electrodes in spaced relation and to permit an electrical field to be established between said electrodes in said treatment region, at least one of said sheet shaped electrodes being perforated according to a certain pattern of perforations, said perforations of said pattern being sufficiently large such as to produce a substantial non-uniformity of the electric field in the electric field treatment region between said sheet electrodes.

43. In a method for electrically treating a fluid stream the steps of:

spacing apart first and second electrode structures to define a composite electrode structure having an electrical treatment region through which a stream of dielectric fluid is to be passed for treatment;

insulating said first and second electrode structures to permit an electrical field to be established between said electrodes in said treatment region;

applying an electrical potential across said first and second electrodes for establishing an electrical field in the treatment region;

incorporating electrical resistance in at least one of said electrode structures in such a manner that, in the presence of an electrical short between said electrodes through the dielectric fluid to be treated in said treatment region, said electrical resistance drops the applied potential across said resistance in a localized portion of said electrode structure such that less than 1/10th of said treatment region is effectively shorted by said electrical short.

44. The method of claim 43 wherein said first and second electrode structures are sheet-shaped and disposed with their broad sides in mutually opposed relation, and including the step of corrugating at least one of said sheet-shaped first and second electrode structures with a mean peak-to-peak depth of said corrugations being greater than 1/4 of the mean spacing between said first and second sheet electrode structures, such corrugations being arranged relative to the opposed electrode surface such as to produce a substantial non-uniform electric field between opposed electrode surfaces.