Soil heating with a rotating electromagnetic field

• US 6,413,399 B1
• Filed: 05/19/2000
• Issued: 07/02/2002
• Est. Priority Date: 10/28/1999
• Status: Expired due to Fees

• Current Assignee: KAI Technologies, Inc.
• Original Assignee: KAI Technologies, Inc.
• Inventors: Kasevich, Raymond S.
• Primary Examiner(s): Phasge, Arun S.
• Application Number:
  US09/574,359
• Time in Patent Office: 774 Days
• Field of Search: 204/515, 204/600, 588/204, 405/131
• US Class Current: 204/515
• CPC Class Codes: A01B 47/00 Soil-working with electric potential applied between tools and soil
• CPC Class Codes: A01B 79/00 Methods for working soil
• CPC Class Codes: A01G 11/00 Sterilising soil by steam
• CPC Class Codes: A01G 7/04 Electric or magnetic or acoustic treatment of plants for promoting growth
• CPC Class Codes: A01M 21/046 by electricity
• CPC Class Codes: B09C 1/06 thermally
• CPC Class Codes: H05B 3/0004 Devices wherein the heating current flows through the material to be heated Circuit arrangements for heating by passing the current directly across the material to be heated H05B3/0023; granular, powdered or fluid material H05B3/60

Abstract

A soil remediation system heats contaminated soil by generating a rotating sub-surface electromagnetic field. The system includes three electrodes disposed 120 degrees apart on a remediation circle. These electrodes are excited by AC voltages with 120 degree phase differences relative to each other. This results in the generation of a sub-surface traveling wave that propagates in a circumferential direction.

Claims

1. A system for heating earthen material with a sub-surface rotating field, said system comprising:

a first electrode in electrical communication with said earthen material, said first electrode being driven by a first AC voltage and being disposed on a circumference of a circle;

a second electrode in electrical communication with said earthen material, said second electrode being driven by a second AC voltage having a 120 degree phase difference relative to said first AC voltage, said second electrode being disposed on said circumference 120 degrees from said first electrode; and

a third electrode in electrical communication with said earthen material, said third electrode being driven by a third AC voltage having a 120 degree phase difference relative to said second AC voltage, said third electrode being disposed on said circumference 120 degrees from said second electrode.

2. The system of claim 1 further comprising a neutral electrode in electrical communication with said first, second, and third electrodes.

3. The system of claim 2 wherein said neutral electrode is disposed at the center of said circle.

4. The system of claim 2 wherein said first electrode and said neutral electrode penetrate the surface of the earth to the same depth.

5. The system of claim 1 wherein said first electrode and said second electrode penetrate the surface of the earth to the same depth.

6. The system of claim 1 wherein said first electrode comprises an insulated section and an uninsulated section in electrical communication with said insulated section.

7. The system of claim 6 wherein said second electrode comprises an insulated section and an uninsulated section in electrical communication with said insulated section and said uninsulated section of said second electrode and said uninsulated section of said first electrode are at substantially the same depth below the surface of the earth.

8. The system of claim 6 wherein said first electrode comprises an insulating jacket movable along a longitudinal axis.

9. A method for heating earthen material, the method comprising the steps of:

inserting first, second, and third electrodes along the circumference of a circle; and

applying first, second, and third voltages to said first, second, and third electrodes respectively, thereby generating a sub-surface rotating electromagnetic field.

10. The method of claim 9 wherein said inserting step comprises the step of inserting said first, second, and third electrodes 120 degrees apart along said circle.

11. The method of claim 9 wherein said step of applying first, second, and third voltages comprises the steps of applying a phase difference of 120 degrees between said first voltage and said second voltage, and applying a phase difference of 240 degrees between said first voltage and said third voltage.

12. The method of claim 9 further comprising the step of positioning said first, second, and third electrodes to generate a heated zone having a specified geometry.

13. The method of claim 12 wherein said positioning step comprises the steps of selecting first, second, and third penetration depths for said first, second, and third electrodes.

14. The method of claim 9 further comprising the step of providing said first electrode with an insulated section having an insulated surface area and an uninsulated section having an uninsulated surface area, said uninsulated section being in electrical communication with said insulated section.

15. The method of claim 14 further comprising the step of adjusting said insulated surface area and said uninsulated surface area to form a heated zone having a prescribed geometry.

16. The method of claim 15 wherein said step of adjusting said insulated area and said uninsulated area comprises the step of adjusting an uninsulated length associated with said uninsulated section and adjusting an insulated length associated with said insulated section.

17. The method of claim 16 wherein said step of adjusting an uninsulated length comprises the step of translating an insulating jacket along a longitudinal axis of said first electrode.

18. A system for heating earthen material with a sub-surface rotating field, said system comprising

a heating element consisting of:

a first electrode in electrical communication with said earthen material, said first electrode being driven by a first AC voltage and being disposed on a circumference of a circle;

a second electrode in electrical communication with said earthen material, said third electrode being driven by a third AC voltage having a 120 degree phase difference relative to said second AC voltage, said third electrode being disposed on said circumference 120 degrees from said second electrode.

19. The system of claim 18 further comprising a neutral electrode in electrical communication with said first, second, and third electrodes.

20. The system of claim 19 wherein said neutral electrode is disposed at the center of said circle.

21. The system of claim 19 wherein said first electrode and said neutral electrode penetrate the surface of the earth to the same depth.

22. The system of claim 18 wherein said first electrode and said second electrode penetrate the surface of the earth to the same depth.

23. The system of claim 18 wherein said first electrode comprises an insulated section and an uninsulated section in electrical communication with said insulated section.

24. The system of claim 23 wherein said second electrode comprises an insulated section and an uninsulated section in electrical communication with said insulated section and said uninsulated section of said second electrode and said uninsulated section of said first electrode are at substantially the same depth below the surface of the earth.

25. The system of claim 23 wherein said first electrode comprises an insulating jacket movable along a longitudinal axis.