Apparatus and method for microwave processing of liquids

• US 6,268,596 B1
• Filed: 08/24/1999
• Issued: 07/31/2001
• Est. Priority Date: 08/24/1999
• Status: Expired due to Fees

• Current Assignee: Lockheed Martin Energy Research Corporation (Martin Marietta Corporation)
• Original Assignee: UT-Battelle LLC
• Inventors: Fathi, Zakaryae, Lauf, Robert J., Tucker, Denise A.
• Primary Examiner(s): Leung, Philip H.
• Application Number:
  US09/379,850
• Time in Patent Office: 707 Days
• Field of Search: 219/687, 219/688, 219/689, 219/745, 219/746, 219/748, 219/749, 219/750, 219/751, 219/756, 219/762, 219/679, 219/686, 219/726, 422/21
• US Class Current: 219/687
• CPC Class Codes: H05B 6/74 Mode transformers or mode stirrers
• CPC Class Codes: H05B 6/782 wherein the material moved is food
• CPC Class Codes: H05B 6/802 for heating fluids methods of heating fluids in conventional microwave ovens H05B6/687

Abstract

A microwave heating apparatus designed to allow concentration of microwave power to a liquid sample to be processed, by use of a field-perturbing tool disposed within or proximate to the volume of liquid. Uniformity of processing is achieved by circulating the liquid past the tool during processing. The apparatus and method is particularly useful when used to excite a nonlinear process whereby greater overall process efficiency may be achieved.

Claims

1. An apparatus for microwave processing a liquid material comprising:

a microwave cavity;

a vessel for containing a liquid material, said vessel at least partially disposed within said cavity;

a microwave source disposed to direct microwaves into said cavity;

at least one field perturbing tool having a selected size, shape, and composition, said tool disposed to apply a controlled, localized concentration of microwave power to at least one selected portion of said liquid material; and

a means for controllably circulating said liquid material relative to said tool so that over time said concentration of microwave power is applied in turn to substantially all portions of said liquid material.

2. The apparatus of claim 1 wherein said field perturbing tool is integral with said means for controllably circulating said liquid material relative to said tool so that said concentration of microwave power is applied to substantially all portions of said liquid material.

3. The apparatus of claim 1 wherein said vessel further comprises an elongated tube, said tube being at least partially transparent to microwave power.

4. The apparatus of claim 1 wherein said tool comprises a plurality of electrically conductive objects.

5. The apparatus of claim 1 wherein said tool comprises at least one electrically conductive object and said vessel is at least partially transparent to microwave power.

6. The apparatus of claim 1 wherein said tool comprises at least one generally planar electrically conductive object, wherein a generally sharp edge of said object is contiguous with said liquid material.

7. The apparatus of claim 1 wherein said tool comprises at least one generally elongated electrically conductive object, wherein a generally sharp point of said object is contiguous with said liquid material.

8. The apparatus of claim 1 wherein said tool is biased at a selected electrical potential relative to ground.

9. The apparatus of claim 1 wherein said microwave processing is selected from the group consisting of chemical synthesis, sterilization, cracking, and polymerization.

10. The apparatus of claim 1 wherein said liquid material is selected from the group consisting of an essentially liquid material, an essentially liquid mixture, a mixture of liquid and solid materials, a mixture of dispersed solid materials in a liquid suspension, and a mixture of two or more immiscible liquids.

11. An apparatus for microwave processing a liquid material comprising:

a microwave cavity;

a vessel for containing a liquid material, said vessel at least partially disposed within said cavity, said vessel maintaining an internal pressure greater than or less than atmospheric;

a microwave source disposed to direct microwaves into said cavity;

at least one field perturbing tool having a selected size, shape, and composition, said tool disposed to apply a controlled, localized concentration of microwave power to at least one selected portion of said liquid material; and

,

a means for controllably circulating said liquid material relative to said tool so that over time said concentration of microwave power is applied in turn to substantially all portions of said liquid material.

12. The apparatus of claim 11 wherein said field perturbing tool is integral with said means for controllably circulating said liquid material relative to said tool so that said concentration of microwave power is applied to substantially all portions of said liquid material.

13. The apparatus of claim 11 wherein said vessel further comprises an elongated tube, said tube being at least partially transparent to microwave power.

14. The apparatus of claim 11 wherein said tool comprises a plurality of electrically conductive objects.

15. The apparatus of claim 11 wherein said tool comprises at least one electrically conductive object and said vessel is at least partially transparent to microwave power.

16. The apparatus of claim 11 wherein said tool comprises at least one generally planar electrically conductive object, wherein a generally sharp edge of said object is contiguous with said liquid material.

17. The apparatus of claim 11 wherein said tool comprises at least one generally elongated electrically conductive object, wherein a generally sharp point of said object is contiguous with said liquid material.

18. The apparatus of claim 11 wherein said tool is biased at a selected electrical potential relative to ground.

19. The apparatus of claim 11 wherein said microwave processing is selected from the group consisting of chemical synthesis, sterilization, cracking, and polymerization.

20. The apparatus of claim 11 wherein said liquid material is selected from the group consisting of an essentially liquid material, an essentially liquid mixture, a mixture of liquid and solid materials, a mixture of dispersed solid materials in a liquid suspension, and a mixture of two or more immiscible liquids.

21. A method for microwave processing a liquid material comprising the steps of:

a. disposing said liquid material in a vessel;

b. disposing said vessel at least partially within a microwave cavity;

c. exposing said liquid material to microwaves from a microwave source disposed to direct microwaves into said cavity;

d. disposing at least one field perturbing tool having a selected size, shape, and composition to apply a controlled, localized concentration of microwave power to at least one selected portion of said liquid material; and

,

e. circulating said liquid relative to said tool whereby said concentration of microwave power is applied in turn to substantially all portions of said liquid material.

22. The method of claim 21 wherein said field perturbing tool is integral with said liquid material so that said concentration of microwave power is applied to substantially all portions of said liquid material.

23. The method of claim 21 further comprising circulating said liquid material between said vessel and an external reservoir.

24. The method of claim 21 wherein said vessel further comprises an elongated tube, said tube being substantially transparent to microwave power.

25. The method of claim 21 wherein said tool comprises a plurality of electrically conductive objects.

26. The method of claim 21 wherein said tool comprises at least one electrically conductive object and said vessel is at least partially transparent to microwave power.

27. The method of claim 21 wherein said tool comprises at least one generally planar electrically conductive object wherein a generally sharp edge of said tool is contiguous with said liquid material.

28. The method of claim 21 wherein said tool comprises at least one generally elongated electrically conductive object wherein a generally sharp point of said tool is contiguous with said liquid material.

29. The method of claim 21 wherein said tool is biased at a selected electrical potential relative to ground.

30. The method of claim 21 wherein said microwave processing is selected from the group consisting of chemical synthesis, sterilization, cracking, and polymerization.

31. The method of claim 21 wherein said liquid material is selected from the group consisting of a substantially fluid material, a substantially fluid mixture, a mixture of fluid and solid materials, a mixture of dispersed solid materials in a liquid suspension, and a mixture of two or more immiscible fluids.

32. A method for microwave processing a liquid material comprising the steps of:

a. disposing said liquid material in a vessel, said vessel maintaining an internal pressure greater than or less than atmospheric;

b. disposing said vessel at least partially within a microwave cavity;

c. exposing said liquid material to microwaves from a microwave source disposed to direct microwaves into said cavity;

d. disposing at least one field perturbing tool having a selected size, shape, and composition to apply a controlled, localized concentration of microwave power to at least one selected portion of said liquid material; and

,

e. circulating said liquid relative to said tool whereby said concentration of microwave power is applied in turn to substantially all portions of said liquid material.

33. The method of claim 32 wherein said field perturbing tool is integral with said liquid material so that said concentration of microwave power is applied to substantially all portions of said liquid material.

34. The method of claim 32 further comprising circulating said liquid material between said vessel and an external reservoir.

35. The method of claim 32 wherein said vessel further comprises an elongated tube, said tube being substantially transparent to microwave power.

36. The method of claim 32 wherein said tool comprises a plurality of electrically conductive objects.

37. The method of claim 32 wherein said tool comprises at least one electrically conductive object and said vessel is at least partially transparent to microwave power.

38. The method of claim 32 wherein said tool comprises at least one generally planar electrically conductive object wherein a generally sharp edge of said tool is contiguous with said liquid material.

39. The method of claim 32 wherein said tool comprises at least one generally elongated electrically conductive object wherein a generally sharp point of said tool is contiguous with said liquid material.

40. The method of claim 32 wherein said tool is biased at a selected electrical potential relative to ground.

41. The method of claim 32 wherein said microwave processing is selected from the group consisting of chemical synthesis, sterilization, cracking, and polymerization.

42. The method of claim 32 wherein said liquid material is selected from the group consisting of a substantially fluid material, a substantially fluid mixture, a mixture of fluid and solid materials, a mixture of dispersed solid materials in a liquid suspension, and a mixture of two or more immiscible fluids.