Plasma generation and processing with multiple radiation sources

• US 7,227,097 B2
• Filed: 05/07/2003
• Issued: 06/05/2007
• Est. Priority Date: 05/08/2002
• Status: Expired due to Fees

• Current Assignee: BTU International, Incorporated (Amtech Systems, Inc.)
• Original Assignee: BTU International, Incorporated (Amtech Systems, Inc.)
• Inventors: Kumar, Devendra, Kumar, Satyendra
• Primary Examiner(s): PASCHALL, MARK H
• Application Number:
  US10/430,415
• Publication Number:
  US 20040001295A1
• Time in Patent Office: 1,490 Days
• Field of Search: 219/121.5, 219/121.36, 219/121.55, 219/121.43, 219/121.4, 219/121.46, 219/121.57, 150/345.38, 150/345.41, 118/724
• US Class Current: 219/121.43
• CPC Class Codes: B01D 2258/01 Engine exhaust gases
• CPC Class Codes: B01D 2259/818 Employing electrical discharges or the generation of a plasma
• CPC Class Codes: B01D 53/92 of engine exhaust gases exhaust or silencing apparatus for internal combustion engines, machines or engines in general, having means for purifying, rendering innocuous or otherwise treating exhaust gases F01N3/00
• 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 19/126 Microwaves
• CPC Class Codes: B01J 2219/00063 of the reactants
• CPC Class Codes: B01J 2219/00193 Sensing a parameter
• CPC Class Codes: B01J 2219/002 inside the reactor
• CPC Class Codes: B01J 2219/00213 Fixed parameter value
• CPC Class Codes: B01J 2219/0024 other than of the reactor or heat exchange system
• CPC Class Codes: B01J 2219/0892 involving catalytically active material
• CPC Class Codes: B01J 2219/0894 Processes carried out in the presence of a plasma
• CPC Class Codes: B01J 2219/1269 Microwave guides
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C22B 4/005 using plasma jets smelting, remelting, refining of metals using a plasma as heat source C22B9/22; generating or handling plasma in general H05H1/00; gas-filled discharge tubes for processing materials in general H01J37/32
• CPC Class Codes: F01N 13/10 of exhaust manifolds with cooling jacket F01N3/046
• CPC Class Codes: F01N 2240/28 a plasma reactor
• CPC Class Codes: F01N 2610/08 with prior mixing of the substances with a gas, e.g. air
• CPC Class Codes: F01N 3/202 using microwaves
• CPC Class Codes: F01N 3/206 : Adding periodically or continuously substances to exhaust gases for promoting purification, e.g. catalytic material in liquid form, NOx reducing agents F01N3/2066 takes precedence
• CPC Class Codes: H01J 2237/0206 : Extinguishing, preventing or controlling unwanted discharges
• CPC Class Codes: H01J 2237/33 : characterised by the type of processing
• CPC Class Codes: H01J 2237/336 : Changing physical properties of treated surfaces
• CPC Class Codes: H01J 2237/338 : Changing chemical properties of treated surfaces
• CPC Class Codes: H01J 37/32009 : Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources plasma generation in general H05H1/24
• CPC Class Codes: H01J 37/32192 : Microwave generated discharge H01J37/32357, H01J37/32366, H01J37/32394, H01J37/32403 take precedence
• CPC Class Codes: H01J 37/32302 : Plural frequencies
• CPC Class Codes: H01J 37/32366 : Localised processing
• CPC Class Codes: H05B 2206/044 : Microwave heating devices provided with two or more magnetrons or microwave sources of other kind
• CPC Class Codes: H05B 6/6402 : Aspects relating to the microwave cavity
• CPC Class Codes: H05B 6/68 : for monitoring or control
• CPC Class Codes: H05B 6/806 : for laboratory use
• CPC Class Codes: H05H 1/46 : using applied electromagnetic fields, e.g. high frequency or microwave energy H05H1/26 takes precedence
• CPC Class Codes: H05H 1/461 : Microwave discharges
• CPC Class Codes: H05H 1/4652 : using inductive coupling means, e.g. coils
• CPC Class Codes: Y02B 40/00 : Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers
• CPC Class Codes: Y02T 10/12 : Improving ICE efficiencies

Abstract

Plasma-assisted methods and apparatus that use multiple radiation sources are provided. In one embodiment, a plasma is ignited by subjecting a gas in a processing cavity to electromagnetic radiation having a frequency less than about 333 GHz in the presence of a plasma catalyst, which may be passive or active. A controller can be used to delay activation of one radiation source with respect to another.

Claims

1. A radiation apparatus, comprising:

a radiation cavity;

a first radiation source for directing electromagnetic radiation having a frequency less than about 333 GHz into the cavity to facilitate formation of plasma in the cavity;

a second radiation source for directing electromagnetic radiation into the cavity;

a controller for sequentially activating the second radiation source after the first radiation source is activated; and

a detector that provides an indication of radiation absorption, and wherein the controller delays activation of the second radiation source until after the controller receives a signal from the detector that a predetermined absorption level has been reached.

2. The apparatus of claim 1, further comprising at least one additional radiation source, and wherein the controller is configured to activate the additional radiation source only after at least one of the first and second radiation sources is activated.

3. The apparatus of claim 1, further comprising a plurality of additional radiation sources, and wherein the controller is configured to activate each of the plurality of additional radiation sources only after at least one of the first and second radiation sources is activated.

4. The apparatus of claim 1, wherein the controller delays activation of the second radiation source for a predetermined period following activation of the first radiation source.

5. The apparatus of claim 1, wherein the first radiation source is configured to generate radiation that is cross-polarized relative to radiation generated by the second radiation source.

6. The apparatus of claim 1, wherein each of the first radiation source and the second radiation source comprises at least one of a magnetron, a klystron, a gyrotron, a traveling-wave tube amplifier, and any other source of radiation.

7. The apparatus of claim 1, further comprising a catalyst located proximate the cavity, for cooperating with the radiation to cause the gas to form a plasma.

8. The apparatus of claim 7, wherein the catalyst is at least one of an active catalyst and a passive catalyst.

9. The method of claim 8, wherein the catalyst comprises at least one of metal, inorganic material, carbon, carbon-based alloy, carbon-based composite, electrically conductive polymer, conductive silicone elastomer, polymer nanocomposite, and an organic-inorganic composite.

10. The method of claim 9, wherein the catalyst is in the form of at least one of a nano-particle, a nano-tube, a powder, a dust, a flake, a fiber, a sheet, a needle, a thread, a strand, a filament, a yarn, a twine, a shaving, a sliver, a chip, a woven fabric, a tape, and a whisker.

11. The method of claim 10, wherein the catalyst comprises carbon fiber.

12. The method of claim 8, wherein the catalyst is in the form of at least one of a nato-particle, a nano-tube, a powder, a dust, a flake, a fiber, a sheet, a needle, a thread, a strand, a filament, a yarn, a twine, a shaving, a sliver, a chip, a woven fabric, a tape, and a whisker.

13. The apparatus of claim 1, further comprising an isolator for protectively separating the second radiation source from the first radiation source.

14. A plasma apparatus, comprising:

a chamber;

a conduit for supplying a gas to the chamber;

a plurality of radiation sources arranged to radiate electromagnetic radiation into the chamber;

a controller for delaying activation of all but a first of the plurality radiation sources until after a first radiation source is activated; and

a detector that provides an indication of radiation absorption, and wherein the controller delays activation of each one of the plurality of radiation sources until after the controller receives a signal from the detector that a predetermined absorption level has been reached.

15. The plasma apparatus of claim 14, wherein the controller delays activation of at least one of the plurality of radiation sources for a predetermined period following activation of the first radiation source and wherein each of the remaining plurality of radiation sources is successively activated at predetermined intervals.

16. The plasma apparatus of claim 14, wherein the first radiation source is configured to generate radiation that is cross-polarized relative to radiation generated by at least one of the plurality of radiation sources.

17. The plasma apparatus of claim 14, wherein each of the first radiation source and each one of the plurality radiation sources comprises at least one of a magnetron, a klystron, a gyrotron, a traveling-wave tube amplifier/oscillator, and any other source of radiation.

18. The plasma apparatus of claim 14, further comprising a catalyst located proximate the cavity, for cooperating with the radiation to cause the gas to form a plasma.

19. The plasma apparatus of claim 18, wherein the catalyst is at least one of an active catalyst and a passive catalyst.

20. The plasma apparatus of claim 19, wherein the catalyst comprises at least one of metal, inorganic material, carbon, carbon-based alloy, carbon-based composite, electrically conductive polymer, conductive silicone elastomer, polymer nanocomposite, and an organic-inorganic composite.

21. The plasma apparatus of claim 20, wherein the catalyst is in the form of at least one of a nanoparticle, a nano-tube, a powder, a dust, a flake, a fiber, a sheet, a needle, a thread, a strand, a filament, a yarn, a twine, a shaving, a sliver, a chip, a woven fabric, a tape, and a whisker.

22. The plasma apparatus of claim 21, wherein the catalyst comprises carbon fiber.

23. The plasma apparatus of claim 19, wherein the catalyst is in the form of at least one of a nanoparticle, a nano-tube, a powder, a dust, a flake, a fiber, a sheet, a needle, a thread, a strand, a filament, a yarn, a twine, a shaving, a sliver, a chip, a woven fabric, a tape, and a whisker.

24. The plasma apparatus of claim 19 wherein the plasma catalyst comprises an active plasma catalyst including at least one ionizing particle.

25. The plasma apparatus of claim 24, wherein the at least one ionizing particle comprises a beam of particles.

26. The plasma apparatus of claim 24, wherein the particle is at least one of an x-ray particle, a gamma ray particle, an alpha particle, a beta particle, a neutron, and a proton.

27. The plasma apparatus of claim 24, wherein the at least one ionizing particle is a charged particle.

28. The plasma apparatus of claim 24, wherein the ionizing particle comprises a radioactive fission product.

29. The plasma apparatus of claim 14, further comprising a plurality of isolators for protectively separating each one of the plurality of radiation sources from each other and from the first radiation source.

30. The plasma apparatus of claim 14, wherein the chamber is a waveguide.