Device and method for determining at least one parameter of a medium

• US 8,618,817 B2
• Filed: 11/07/2007
• Issued: 12/31/2013
• Est. Priority Date: 11/08/2006
• Status: Active Grant

• Current Assignee: Technische Universitã¤T Darmstadt
• Original Assignee: Technische Universitã¤T Darmstadt
• Inventors: Jakoby, Rolf, Schuessler, Martin, Penirschke, Andreas, Maune, Holger
• Primary Examiner(s): Hollington, Jermele M
• Assistant Examiner(s): Rhodes-Vivour, Temilade S
• Application Number:
  US12/514,308
• Publication Number:
  US 20100148804A1
• Time in Patent Office: 2,246 Days
• Field of Search: 324/452, 324/453, 324/663, 324/667, 324/668, 324/71.1
• US Class Current: 324/663
• CPC Class Codes: G01F 1/662 Constructional details
• CPC Class Codes: G01F 1/74 Devices for measuring flow of a fluid or flow of a fluent solid material in suspension in another fluid
• CPC Class Codes: G01N 27/221 by investigating the dielectric properties using microwaves G01N22/00; measuring loss factors or dielectric constants per se G01R27/26
• CPC Class Codes: H01Q 15/0046 Theoretical analysis and design methods of such selective devices
• CPC Class Codes: H01Q 15/0086 said selective devices having materials with a synthesized negative refractive index, e.g. metamaterials or left-handed materials

Abstract

The invention relates to a device for determining at least one parameter of at least one medium, said medium being introducible into at least one measuring path. An electric and/or electromagnetic field can be partially coupled into or out of the medium by passing at least one electric and/or electromagnetic signal into the measuring path. The measuring path comprises at least one line arrangement having at least two elementary cells arranged along the measuring path, said elementary cells comprising at least one electric path from at least one input to at least one output and comprising at least one respective capacitative element. The electrical properties of the capacitative element can by be modified by the medium. The electric and/or the electromagnetic signal can be applied to the input of a first elementary cell and the output of the first elementary cell can be connected to the input of a second elementary cell. The capacitative element of the respective elementary cell is arranged in the electric path of the first and second elementary cell. At least one inductive element connects the first elementary cell and the second elementary cell to a ground. The invention also relates to a method for determining a parameter of a medium.

Claims

1. A device comprising:

a measuring path having a line system that includes at least two elementary cells situated along the measuring path, each elementary cell comprising an electrical path from at least one input to at least one output, wherein the elementary cells each comprise at least one capacitive element;

a generator for generating an electrical or electromagnetic signal that is supplied to the input of a first elementary cell, the output of the first elementary cell being connected to the input of a second elementary cell such that said first and second elementary cells are connected in series, and the capacitive element of the respective first and second elementary cells being situated in the electrical path of the first and second elementary cells, and in each case at least one inductive element connects the electrical path of the first elementary cell and the second elementary cell to an electrical ground; and

an evaluation device for analyzing an output signal of the measuring path,

wherein the evaluation device is configured to determine at least one parameter of a medium that is introduced into the measuring path such that an electrical property of the capacitive element of an elementary cell is modified by the medium, and

wherein an electromagnetic field is coupled into and/or out of the medium by introducing the electrical or electromagnetic signal into the measuring path.

2. The device according to claim 1, wherein a dimension of at least one elementary cell is smaller than a wavelength of the electrical or electromagnetic signal or a wavelength of the electromagnetic field.

3. The device according to claim 1, wherein the at least one parameter of the medium includes a relative dielectric constant, a relative permeability constant, a type of the medium, a density distribution or density of the medium, a distribution of the medium in the measuring path, a velocity of the medium in the measuring path, a quantity flow or mass flow of the medium through the measuring path, or a phase state of the medium.

4. The device according to claim 1, wherein the medium that is introduced into the measuring path has at least one form selected from a group consisting of a fluid form, a solid form, a gaseous form, and a two-phase form, including liquid-gaseous, liquid-liquid, liquid-solid, gaseous-solid, solid-solid, gaseous-gaseous, or liquid-gaseous-solid form.

5. The device according to claim 1, wherein the medium is movable relative to the line system.

6. The device according to claim 1, wherein the measuring path further includes at least one conducting unit for conducting the medium, and wherein the line system is provided on a surface of the conducting unit such that the electromagnetic field is injected into the medium.

7. The device according to claim 6, wherein the conducting unit has, at least in places, a cross-sectional shape that is circular, oval, elliptical, triangular, square, rectangular, or polygonal, or segments of these cross sections including a circular segment or ellipsoidal segment.

8. The device according to claim 6, wherein the conducting unit includes at least one of a dielectric and diamagnetic material, a synthetic material, and an elastically or plastically deformable material.

9. The device according to claim 6, wherein the medium is provided in or conducted through the conducting unit.

10. The device according to claim 9, further comprising a conveying unit that operates by one of hydraulic, pneumatic, magnetic, or gravitational means via which the medium is conducted through the conducting unit.

11. The device according to claim 6, wherein the conducting unit is movable relative to the line system.

12. The device according to claim 1, wherein the electrical or electromagnetic signal is a high-frequency signal that is introduced into the measuring path or a high-frequency electromagnetic radiation that is coupled into the medium.

13. The device according to claim 1, wherein at least one output of the generator is connected to at least one input of the electrical path of the first elementary cell using a coaxial cable, and wherein at least one conductor of the coaxial cable is connected to the electrical ground.

14. The device according to claim 6, wherein the line system includes at least one capacitive element comprising a first charging element and a second charging element in the form of at least one pair of capacitor plates, and wherein the first and second charging elements are situated on at least one side facing away from the medium, on a surface of the conducting unit that includes at least one of an electrically conductive material, a semiconductor material, and a polymeric material.

15. The device according to claim 14, wherein the electromagnetic field is generated between the first and the second charging element and wherein the electromagnetic field is generated between charging elements of different elementary cells.

16. The device according to claim 14, wherein the medium is situated between the first and second charging elements.

17. The device according to claim 14, wherein the first and second charging elements are situated opposite from one another in a parallel manner.

18. The device according to claim 14, wherein the first and second charging elements are offset relative to each other along at least one longitudinal axis of the conducting unit.

19. The device according to claim 1, wherein the line system further comprises a third elementary cell, the capacitive element of the third elementary cell being situated in the electrical path of the third elementary cell,

wherein at least one inductive element connects the electrical path of the third elementary cell to the electrical ground, wherein the third elementary cell is inserted between the first and second elementary cells such that an input of the electrical path of the third elementary cell is connected in series to the output of the electrical path of the first elementary cell in place of the second elementary cell, and wherein an output of the electrical path of the third elementary cell is connected in series to the input of the electrical path of the second elementary cell.

20. The device according to claim 19, wherein the device includes a plurality of third elementary cells, wherein an output of the electrical path of one third elementary cell is connected in series to an input of the electrical path of another third elementary cell.

21. The device according to claim 19, wherein at least two of the first, second, or third elementary cells or a combination thereof are periodically oriented toward one another.

22. The device according to claim 1, wherein at least one input of the evaluation device is connected to at least one output of the electrical path of the second elementary cell or at least one output of the generator using a coaxial cable, wherein at least one conductor of the coaxial cable is connected to the electrical ground.

23. The device according to claim 22, wherein an input of the evaluation device is connected to the input of the electrical path of the first elementary cell using coaxial cable, and wherein at least one conductor of the coaxial cable is connected to the electrical ground and/or the output of the electrical path of the second elementary cell is connected to the electrical ground.

24. The device according to claim 1, wherein the evaluation device compares an electrical or electromagnetic input signal that is present at the input of the electrical path of the first elementary cell with an electrical or electromagnetic output signal that is present at the output of the electrical path of the second elementary cell or with an electrical or electromagnetic signal that is present after passing at least partially through the line system.

25. The device according to claim 24, wherein the evaluation device detects at least one absolute value of an amplitude, at least one phase, or at least one phase angle, of the at least one electrical or electromagnetic input signal or of the at least one electrical or electromagnetic output signal.

26. The device according to claim 25, wherein at least one phase angle change between the at least one electrical or electromagnetic input signal and the at least one electrical or electromagnetic output signal is detected.

27. The device according to claim 1, wherein the evaluation device includes at least one processor unit and at least one visual or acoustic output device for outputting the determined parameter of the medium.

28. The device according to claim 1, wherein the evaluation device includes a first evaluation unit for determining a first parameter of the medium and a second evaluation unit for determining a second parameter of the medium.

29. The device according to claim 28, wherein the evaluation device further includes a third evaluation unit for determining a third parameter of the medium based on the first and second parameters of the medium.

30. The device according to claim 28, wherein the evaluation device further includes at least one transformation unit for transforming the electrical or electromagnetic output signal of the measuring path and at least one comparative signal determined by a comparison of the input signal of the measuring path with the electrical or electromagnetic output signal of the measuring path, and wherein the first evaluation unit and the second evaluation unit are operatively connected to the transformation unit, and the first evaluation unit and the second evaluation unit are connected to the measuring path via the transformation unit.

31. The device according to claim 1, wherein at least one input of an elementary cell and at least one output of at least one additional elementary cell are directly connected to one another in series.

32. The device according to claim 1, wherein the electrical or electromagnetic signal is supplied via at least one input or at least one output of at least one elementary cell, and an output signal is extracted at the same input or output of the at least one elementary cell.

33. The device according to claim 19, wherein at least one inductive element of the first, second, and/or third elementary cell includes at least one conductor.

34. The device according to claim 6, wherein the elementary cells are associated with the conducting unit along at least one longitudinal direction and/or at least one radial direction.

35. A method for determining at least one parameter of a medium by using a device according to claim 1, the method comprising:

introducing the medium into a measuring path that includes a capacitive element that interacts with the medium, wherein the at least one parameter is determined based on at least one change in at least one electrical property of the capacitive element;

supplying a high-frequency input signal to the measuring path to generate within the measuring path at least one zeroth-order and/or negative-order harmonic electromagnetic oscillation;

determining at least one amplitude, at least one phase angle change, and/or at least one phase angle of the oscillation after the input signal passes through the measuring path; and

determining the parameter of the medium based on the determined amplitude, phase angle, or phase angle change.

36. The method according to claim 35, wherein the input signal is supplied to a line system comprising a series connection of at least two elementary cells, each elementary cell having at least one capacitive element and at least one inductive element, wherein the capacitive elements of the at least two elementary cells are connected in series and the inductive elements of the at least two elementary cells connect the capacitive elements to an electrical ground.

37. The method according to claim 35, wherein an absolute value of an amplitude and/or phase angle between the current and voltage of the oscillation is determined, and wherein the parameter of the medium is determined by a time-based comparison of the input signal and an output signal of the measuring path or by a time-based comparison of a first electromagnetic oscillation without influence of the medium on the measuring path and a second electromagnetic oscillation with the influence of the medium on the measuring path.

38. The method according to claim 35, wherein pneumatically conveyed dust-like materials comprising an organic material, an inorganic material, liquids, bodily fluids, or a bulk material are used as the medium.

39. The method according to claim 35, further comprising transforming at least one of an output signal of the measuring path and a comparative signal into a transformed signal, wherein the comparative signal represents a phase difference and is obtained by comparing the input signal and the output signal of the measuring path.

40. The method according to claim 39, further comprising using a first evaluation unit to determine a first parameter of the medium based on at least one of the output signal of the measuring path, the input signal of the measuring path, the comparative signal, and the transformed signal.

41. The method according to claim 40, further comprising using a second evaluation unit to determine a second parameter of the medium based on at least one of the output signal of the measuring path, the input signal of the measuring path, the comparative signal, and the transformed signal.

42. The method according to claim 41, further comprising filtering at least one of the output signal of the measuring path, the input signal of the measuring path, the comparative signal, and the transformed signal using at least one filter unit included in the first evaluation unit or the second evaluation unit.

43. The method according to claim 42, wherein the first parameter is determined based on an average value of the output signal of the measuring path, the input signal of the measuring path, the comparative signal, the transformed signal, the filtered output signal of the measuring path, the filtered input signal of the measuring path, the filtered comparative signal, and/or the filtered transformed signal, and

wherein the second parameter is determined based on a maximum value of the output signal of the measuring path, the input signal of the measuring path, the comparative signal, the transformed signal, the filtered output signal of the measuring path, the filtered input signal of the measuring path, the filtered comparative signal, and/or the filtered transformed signal.

44. The method according to claim 41, further comprising using a third evaluation unit to determine a third parameter of the medium based on the first parameter and the second parameter.

45. The method according to claim 35, wherein the at least one parameter of the medium is a relative dielectric constant, a relative permeability constant, a type of the medium, a density distribution or density of the medium, a distribution of the medium in the measuring path, a velocity of the medium in the measuring path, a quantity flow or mass flow of the medium through the measuring path, or a phase state of the medium.

46. The method according to claim 43, wherein the maximum value is at least one of a maximum point of a function, a magnitude of a maximum value, and a number of maximum values, the maximum value being determined by at least one time-based derivation or a derivation according to a frequency.

47. The device according to claim 12, wherein the high-frequency signal is a microwave signal or millimeter wavelength signal, and the high-frequency electromagnetic radiation is microwave radiation or millimeter wavelength radiation.

48. The device according to claim 14, wherein the first and second charging elements are situated on opposite sides of the conducting unit.

49. The device according to claim 25, wherein the at least one phase angle change is detected between the voltage and current.

50. The device according to claim 28, wherein the first parameter of the medium is a density of the medium and the second parameter of the medium is a velocity of the medium.

51. The device according to claim 29, wherein the third parameter of the medium is a quantity flow or mass flow of the medium through the measuring path.