Dielectric liquid-immersed corona generator

• US 3,899,683 A
• Filed: 10/26/1973
• Issued: 08/12/1975
• Est. Priority Date: 01/04/1967
• Status: Expired due to Term

• Current Assignee: Atlantic Richfield Company Incorporated (BP PLC)
• Original Assignee: Frank E. Lowther
• Inventors: Lowther, Frank E.
• Primary Examiner(s): Mack, John H.
• Assistant Examiner(s): Weisstuch, Aaron
• Application Number:
  US05/409,802
• Time in Patent Office: 655 Days
• Field of Search: 250/530-542 204/176
• US Class Current: 422/186.2
• CPC Class Codes: B01J 2219/0849 Corona pulse discharge
• CPC Class Codes: C01B 13/11 by electric discharge
• CPC Class Codes: C01B 2201/12 Plate-type dischargers
• CPC Class Codes: C01B 2201/34 Composition of the dielectrics
• CPC Class Codes: C01B 2201/74 by liquid

Abstract

A plurality of air-tight corona generating cells of a corona generator are supported in a liquid-tight housing where they are immersed in a dielectric liquid such as transformer oil for preventing arcing between the edges of the two electrodes of each corona generating cell. The dielectric liquid is in heat exchange relationship with the external surface of each electrode and is circulated between a cooler and the housing for cooling the electrodes. A center support disc located between the electrodes of a cell unexpectedly increases the ozone yield.

Claims

1. A dielectric liquid-immersed corona generator comprising:

a. a fluid-tight housing;

b. a heat exchanger;

c. means for pumping a dielectric liquid from said housing to said heat exchanger and back to said housing;

d. a corona generator positioned within said housing and including a plurality of gas-tight corona generating cells, each cell comprising a pair of flat, solid, spaced-apart electrodes forming a corona discharge chamber between inner facing surfaces of said electrodes, a layer of dielectric material coated on the inner surface of each of said electrodes, a gasket positioned between said pair of electrodes adjacent the peripheries thereof and defining, along with said inner facing surfaces of said pair of electrodes, said corona discharge chamber therewithin, said gasket also determining the thickness of said corona discharge chamber and a spacer element positioned between each adjacent pair of cells and in contact with the external surface of the adjacent electrodes of the adjacent cells, said spacer elements including gas passageways therethrough, and including means for holding said cells and said spacer elements together;

e. a gas inlet and a gas outlet conduit extending through said housing and into gas communication with the corona discharge chamber of each of said cells for feeding oxygen-containing gas into the ozone-containing gas from, said chambers;

f. means including a solid electrical conductor connected to said electrodes for applying a voltage across the electrodes of each of said cells, and g. a disc centrally located in each of said discharge chambers and having a thickness substantially equal to that of said gasket for maintaining said electrodes flat and providing a more uniform air flow through said chamber.

2. The apparatus according to claim 1 wherein each of said discs includes two flat surfaces, each of which flat surfaces is in contact with a respective one of the inner facing surfaces of said pair of electrodes of each cell.

3. The apparatus according to claim 2 wherein said disc takes up approximately 1/100 of the volume of said chamber.

4. The apparatus according to claim 2 wherein said disc is made of the same material as that of said gasket.

5. A corona reactor core including a plurality of adjacent corona reactor cells each comprising a pair of flat, parallel, spaced-apart, dielectric-coated, electrodes, and means defining an airtight corona discharge chamber therebetween, means in contact with the external surface of each electrode for maintaining said electrodes flat and parallel at chamber pressures higher than ambIent, and means located inside of said chamber and in contact with the internal surface of each electrode for maintaining said electrodes flat at chamber pressures lower than ambient.

6. The apparatus according to claim 5 wherein each electrode has an internal dielectric-coated surface and an external heat exchange surface.

7. The apparatus according to claim 6 wherein said electrodes are relatively thin and are deflectable under chamber pressures higher than ambient, including a spacer element positioned between each adjacent pair of cells and in contact with the external surface of the adjacent electrodes of the adjacent cells, said spacer elements including gas passageways therethrough, and including means for holding said cells and said spacer elements together.

8. The apparatus according to claim 7 wherein said spacer elements are electrically conductive and provide electrical connection between said adjacent electrodes of said adjacent cells.

9. The apparatus according to claim 5 wherein said means for maintaining said electrodes flat at chamber pressures lower than ambient comprises a flat element substantially centrally located in said chamber and extending from one electrode to the other.

10. The apparatus according to claim 9 wherein said element is a right circular cylinder.

11. The apparatus according to claim 10 wherein said element takes up between about 1/30 - 1/200 of the volume of said chamber.

12. The apparatus according to claim 11 including a flat, one-piece gasket located between internal facing surfaces of said electrodes adjacent their peripheries and wherein said element has the same thickness and is formed of the same material as that of said gasket.

13. A corona reactor core including a plurality of adjacent corona reactor cells each comprising a pair of flat, parallel, spaced-apart, dielectric-coated, electrodes, and means defining an airtight corona discharge chamber therebetween, means for feeding a fluid into and out of said chamber, and means positioned in said chamber for making the fluid flow through said chamber smooth, laminar, and uniform.

14. The apparatus according to claim 13 wherein said electrodes are rectangular, wherein said feeding means includes spaced-apart, separate, inlet and outlet openings through at least one of said electrodes, and wherein said means comprises a single, right circular cylindrical element, centrally positioned in said chamber and extending between and in contact with both of said electrodes.

15. The apparatus according to claim 14 wherein said openings are on opposite sides of said element and wherein said means takes up between about 1/30 - 1/200 of the volume of said chamber.

16. A method for preventing electrical discharge between the adjacent peripheries of a pair of spaced-apart electrodes of an airtight corona generating cell, said electrodes including internal surfaces defining a corona generating chamber and external heat exchange surfaces, said method comprising immersing said cell in a dielectric liquid and surrounding said peripheries with said dielectric liquid, cooling said liquid whereby said liquid serves to simultaneously prevent said discharge and to cool said cell, providing a plurality of said cells in a housing, filling said housing with said dielectric liquid, and circulating said dielectric liquid from said housing to a cooler and back to said housing, said electrodes being flat and parallel and providing a stack of said cells spaced apart by spacer means contacting said external surfaces and providing liquid coolant passageways through said spacers, providing a gasket of fluorosilicon rubber material between each pair of electrodes of each cell adjacent the peripheries of said electrodes for setting the distance therebetween, and maintaining said electrodes flat by providing a disc centrally located between each pair of electrodes of each cell and having a thickness substantially equal to the thickness of each of said gaskets.