Plasma-based de-icing
An electrical conductor and a gas-filled layer are located at or near the surface of an object being deiced. The conductor carries an AC voltage that generates an alternating electric field in the gas-filled layer. A conductive layer increases the electric field strength in the gas-filled layer between the electrical conductor and the conductive layer. The alternating electric field causes electric breakdown of gas and plasma-formation in the gas-filled layer. The plasma absorbs energy released during electric discharge through the plasma, which heats ice, causing it to melt. The alternating electric field typically has a field strength in a range of about from 1 to 100 kV/cm. The AC voltage typically has an amplitude in a range of about from 10 kV to 1300 kV, and a frequency in a range of about from 50 Hz to 1 MHz. The gas-filled layer includes a plasma-forming gas selected from, among others, air, nitrogen and argon.
1. A system for melting ice, comprising:
an electrical conductor for generating an AEF in response to an AC voltage;
a gas-filled layer proximate to the electrical conductor, the gas-filled layer containing a plasma-forming gas for forming a plasma in response to an AEF; and
a permanent outer shell, wherein the gas-filled layer is disposed between the electrical conductor and the permanent outer shell.
2. A system as in claim 1 , wherein the permanent outer shell comprises a conductive layer.
3. A system as in claim 1 , wherein ice on the permanent outer shell forms a conductive layer.
4. A system as in claim 1 , wherein the electrical conductor is a main conductor of a power transmission line.
5. A system as in claim 1 , further comprising:
an AC power source for applying an AC voltage to the electrical conductor.
6. A system as in claim 1 , further comprising:
an AC voltage in the electrical conductor that generates an AEF, which AEF causes electric breakdown in the gas-filled layer.
7. A system as in claim 6 , wherein the AC voltage has a frequency in a range of about from 50Hz to 1 MHz.
8. A system as in claim 6 , wherein the AC voltage has a voltage in a range of about from 10 kV to 1300 kV.
9. A system as in claim 1 , wherein the gas-filled layer comprises a gas selected from the group consisting of air, nitrogen and argon.
10. A system as in claim 1 , wherein the gas-filled layer has a thickness in a range of about from 0.5 to 10 mm.
11. A system as in claim 1 , wherein the permanent outer shell is electrically nonconductive.
12. A system as in claim 1 , wherein the permanent outer shell is electrically conductive.
13. A system as in claim 12 , further comprising a switch for electrically shorting the electrical conductor and the conductive permanent outer shell.
14. A system as in claim 1 , wherein the gas-filled layer comprises gas-containing balls.
15. A system as in claim 1 , wherein the permanent outer shell is a flexible band and wherein the gas-filled layer is contained within the flexible band.
16. A system for generating heat, comprising:
an electrical conductor for generating an AEF in response to an AC voltage;
a gas-filled layer proximate to the electrical conductor, the gas-filled layer containing a plasma-forming gas for forming a plasma in response to the AEF;
an AC power source for applying an AC voltage to the electrical conductor; and
a permanent outer shell, wherein the gas-filled layer is disposed between the electrical conductor and the permanent outer shell.
17. A system as in claim 16 , wherein the permanent outer shell comprises a conductive layer.
18. A system as in claim 16 , wherein the AC power source provides an AC voltage for generating an AEF having sufficient field strength to cause electric breakdown of gas in the gas-filled layer when a conductive layer is proximate to the electrical conductor.
19. A system as in claim 16 , wherein the AC power source provides an AC voltage for generating an AEF having a strength in a range of about from 1 to 100 kV/cm.
20. A system as in claim 16 , wherein the AC power source provides and AC voltage in a range of about front 10 kV to 1300 kV.
21. A system as in claim 16 , wherein the AC power source provides an AC voltage having a frequency in a range of about from 50 Hz to 1 MHz.
22. A method for melting ice, comprising a step of:
generating an AEF in a gas-filled layer proximate to the ice for causing electric breakdown of gas and the formation of plasma in the gas-filled layer, wherein the gas-filled layer is disposed between an electrical conductor and a permanent outer shell.
23. A method as in claim 22 , wherein the step of generating an AEF includes generating an AEF having a strength in a range of about from 1 to 100 kV/cm.
24. A method as in claim 22 , wherein the step of generating an AEF includes applying an AC voltage to an electrical conductor.
25. A method as in claim 24 , wherein applying an AC voltage to the electrical conductor includes applying a voltage in a range of about from 10 kV to 1300 kV.
26. A method as in claim 24 , wherein applying an AC voltage to the electrical conductor includes applying a voltage with a frequency in a range of about from 50 Hz to 1 MHz.
27. A method as in claim 24 , wherein the electrical conductor is a main conductor of a power transmission line.
28. A meted as in claim 22 , wherein ice on the permanent outer shell forms a conductive layer.
29. A method as in claim 22 , wherein the permanent outer shell comprises a conductive layer.
30. A method as in claim 29 , wherein the conductive layer includes a conductive metal-containing material.