DIELECTRIC LIQUID-IMMERSED CORONA GENERATOR

• US 3,836,786 A
• Filed: 08/17/1972
• Issued: 09/17/1974
• 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): Edmundson, F. C.
• Application Number:
  US05/281,451
• Time in Patent Office: 761 Days
• Field of Search: 204/176 250/531-540
• US Class Current: 422/186.19
• CPC Class Codes: B01J 19/088 giving rise to electric discharges for heating purposes H05B7/00; for the production of ozone C01B13/11, H01T19/00
• 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
• CPC Class Codes: H01T 19/00 Devices providing for corona discharge for charging electrographic elements G03G15/02

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. In a corona generator comprising at least one corona generating cell including a pair of spaced-apart electrodes, and a gasket positioned between said electrodes adjacent the edges thereof for positioning said electrodes a predetermined distance apart and for forming an air-tight corona discharge chamber between interior facing surfaces of said electrodes and inside said gasket, said gasket having an outer edge that does not extend beyond said edges of said electrodes, the improvement comprising a housing, said at least one cell located inside said housing, and a quantity of dielectric liquid substantially filling said housing and surrounding said at least one cell and being in heat exchange relationship with an external surface of each of said electrodes and surrounding and being in contact with said edges of said electrodes, whereby said dielectric liquid provides a dielectric between said adjacent edges of said electrodes outside of said chamber to prevent edge sparking and also cools said electrodes.

2. The apparatus according to claim 1 wherein said dielectric liquid is transformer oil.

3. The apparatus according to claim 1 wherein said dielectric liquid is a liquid silicon composition.

4. The apparatus according to claim 1 wherein said gasket is formed from a fluorosilicon material and is a one-piece element.

5. The apparatus according to claim 4 wherein said dielectric liquid is transformer oil and wherein said electrodes are flat and parallel, and each of said inner surfaces have a hard, fired-on coating of porcelain enamel thereon less than 20 mils thick.

6. The apparatus according to claim 5 including a dielectric liquid filling said housing.

7. A dielectric liquid-immersed corona generator comprising:

a. a fluid-tight housing substantially filled with a dielectric liquid;

b. a heat exchanger;

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

d. a corona generator core positioned within said housing and including a plurality of separate, spaced-apart gas-tight corona generating cells, each cell comprising a pair of spaced-apart electrodes forming a corona discharge chamber between facing surfaces of said electrodes said electrodes each having its outer surface in heat exchange relationship with said dielectric liquid, a layer of dielectric material in said chamber and between said inner facing surfaces of said electrodes, a gasket positioned between said pair of electrodes adjacent the edges thereof and defining, along with said inner facing surfaces of said pair of electrodes, said corona discharge chamber therewithin said edges of said electrodes being in contact with and being surrounded with said dielectric liquid;

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 and ozone-containing gas from, said chambers; and

f. means for applying an a.c. voltage across the electrodes of each of said cells.

8. The apparatus according to claim 7 wherein said gasket is formed from a fluorosilicon material and is a one-piece element.

9. The apparatus according to claim 8 wherein said dielectric liquid is transformer oil and wherein said electrodes are flat and parallel, and each of said inner surfaces have a hard, fired-on coating of porcelain enamel thereon less than 20 mils thick.

10. The apparatus according to claim 8 wherein said dielectric is transformer oil.

11. The apparatus according to claim 8 wherein said dielectric liquid is a liquid silicon composition.

12. The apparaTus according to claim 7 wherein said gasket has an outer edge that does not extend beyond said edges of said electrodes.

13. The method for simultaneously preventing electrical discharge between the adjacent peripheries of a pair of spaced-apart electrodes of an airtight corona generating cell and cooling said cell, comprising immersing said entire cell in a dielectric liquid such that said liquid is in contact with and surrounds the outer surfaces of said electrodes and said peripheries of said electrodes for cooling said electrodes and for preventing edge sparking.

14. The method according to claim 13 including cooling said liquid.

15. The method according to claim 14 including providing a plurality of said cells in a housing, substantially filling said housing with said dielectric liquid, and circulating said dielectric liquid from said housing to a cooler and back to said housing.

16. The method according to claim 15 wherein said electrodes are 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.

17. The method according to claim 16 wherein each cell includes a gasket between each pair of electrodes of each cell adjacent the peripheries of said electrodes for setting the distance therebetween, and wherein an outer edge of said gasket does not extend beyond said peripheries of said electrodes.

18. The method according to claim 15 wherein said liquid is transformer oil.