Processing

Please wait...

Settings

Settings

1. CA2209789 - PROCESS AND APPARATUS FOR ULTRASOUND FLOW RATE MEASUREMENT

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters
CLAIMS:
1. An ultrasound method of measuring the rate of flow of a flowing medium, using a measuring tube and at least two pairs of ultrasound transducers arranged on the measuring tube forming a measuring path, in which the rate of flow of the flowing medium is determined from the velocities of the medium along at least two measuring paths, wherein the Reynolds' number of the flowing medium is measured continuously and the value for the rate of flow is corrected using the value for the Reynolds' number, wherein the
Reynolds' number is determined using the velocities of the medium along at least two measuring paths.
2. The method according to claim 1, characterized by the fact that the rate of flow is corrected using the value for the Reynolds' number and an error curve based on empirical data.
3. The method according to claim 1, characterized by the fact that the
Reynolds' number is determined using an arithmetical algorithm from the velocities of the medium along different measuring paths.
4. The method according to claim 3, characterized by the fact that the
Reynolds' number is determined based on ratios of said velocities along different measuring paths.
5. The method according to claim 3, characterized by the fact that the
Reynolds' number is determined based on subtractions of the velocities along different measuring paths.
6. An ultrasound method of measuring the rate of flow of a flowing medium, using a measuring tube and at least two pairs of ultrasound transducers arranged on the measuring tube forming a measuring path, in which the rate of flow of the flowing medium is determined from the velocities of the medium along at least two measuring paths, wherein the Reynolds' number of the flowing medium is measured continuously and the value for
the rated of flow is corrected using the value for the Reynolds' number, wherein the velocities of the flowing medium V1, V2, V3, V4 and V5 are determined along five different measuring paths 1 to 5, and wherein a turbulent flow for (V2+V4)/V3 > 1, 9 and a laminar flow for (V2+V4)/V3 < 1, 9 is assumed.
7. The method according to claim 6, wherein in the case of a turbulent flow, the
Reynolds' number is determined from the velocity ratios or differences in the sum of the velocities along measuring paths 2 and 4 (V2+V4) and the measuring paths 1 and
(V2+V5), and wherein in the case of a laminar flow it is determined from the velocity ratios or differences in the sum of the velocities along measuring paths 2 and 4 (V2+V4) and measuring path 3 (V3).
8. The method according to claim 7, wherein for a laminar flow, the Reynolds' number is determined from the velocity ratios as follows:
Re1 = 19100((V2 + V4)/V3)2-60200(V2 + V4)/V3 + 47700
9. The method according to claim 8, wherein for a turbulent flow, the
Reynolds' number is determined as follows from the velocity ratios:
Re t < 30000 Re t = 6500 + 39000((5,14(V2 + V4)/V1 +V5)-5,22)1/2
Re t > 20000 Re t = 5080000((V2 + V4)/(V1 + V5))2
- 108600000(V2 + V4)/(V1 + V5)+5833000
10. The method according to claim 8, wherein for laminar flow, the Reynolds' number is determined from the velocity difference as follows:
Re1 = A1((V2 + V4)-(V1 + V5)/2)2 + B1((V2 + V4)-(V1 + V5))/2+C1 where A1, B1 and C1 are determined empirically.
11. The method according to claim 8, wherein for a turbulent flow, the
Reynolds' number is determined as follows from the velocity differences:
Re t < 30000 Re t = A2((V2 + V4)-(V1 + V5)/2)2 + B2((V2 + V4) - (V1 + V5))/2 +
Re t > 20000 R t = A3((V2 + V4)-(V1 + V5)/2)2 + B3(V2 + V4)-(V1 + V5))/2+C3, where A2, B2, C2, A3, B3, and C3 are determined empirically.
12. The method according to claim 6, wherein in a calibration process, calibration flow profiles that are as undisturbed as possible are recorded from the velocities of the medium along the measuring paths for various rates of flow and Reynolds' numbers.
13. The method according to claim 12, wherein in a calibration process, at least one operating flow profile is recorded with the help of a device mounted and ready to operate that uses the method according to any one of claims 6 to 12.
14. The method according to claim 13, wherein deviations between the calibration flow profiles and the operating flow profiles are corrected arithmetically.
15. The method according to claim 14, wherein for Reynolds' numbers greater than 100,000 to record the operating flow profile, rates of flow for the medium are set that correspond as much as possible to the rates of flow when the calibration flow profile is recorded, wherein the ratios between the individual velocities along the measuring paths of the calibration flow profile and the operating flow profile are determined, wherein with these ratios, the current measured velocities along the measuring paths are corrected, and wherein that with this correction, the measured velocities are also corrected with the ratios of the rates of flow when the calibration flow profiles are recorded and when the reference flow profiles are recorded.
16. The method according to claim 15, wherein the correction factors between the rates
of flow set during the recording of the calibration flow profile and the operating flow profile are determined using interpolation.
17. The method according to claim 14, wherein especially for Reynolds' numbers smaller than 100,000, the calibration profiles are measured and stored in dimensionless form for a large number of Reynolds' numbers, wherein the current measured velocities and the current rate of flow for a dimensionless current flow profile are processed, and wherein the dimensionless current flow profile is compared with the calibration flow profiles and corrected by using said comparison.
18. The method according to claim 17, wherein: the Reynolds' number in zero approximation is determined from the current flow profile; the average velocity is determined from the flow profile stored for the
Reynolds' number in zero approximation; the average velocity from the memory is compared with the current average velocity, if there is a deviation between the average velocities above a predetermined limit, a new current average velocity is assumed that deviates less from the average velocity from the memory; the Reynolds' number is determined in first approximation from the new currently determined velocity; the average velocity is determined again from the flow profile stored with the
Reynolds' number in first approximation; if there is a new deviation above the predetermined limit, a new current average velocity is again taken that deviates less from the average velocity from the memory; and otherwise, the last value for the Reynolds' number is used for further processing.
19. The method according to claim 6, wherein the viscosity of the medium is determined using the rate of flow, the diameter of the measuring tube and the Reynolds' number.
20. The method according to claim 19, wherein the medium is identified using the
viscosity and particularly other medium-dependent measured variables.
21. The method according to claim 20, wherein the ultrasound velocity and/or the ultrasound damping of the medium are determined as another medium dependent measured variable.
22. The method according to claim 6, wherein the rate of flow is corrected using the value for the Reynolds' number and an error curve based on empirical data.
23. The method according to claim 6, wherein the Reynolds' number is determined using the velocities of the medium along at least two measuring paths.
24. The method according to claim 23, wherein the Reynolds' number is determined using an arithmetical algorithm from the velocities of the medium along different measuring paths.
25. The method according to claim 24, wherein the Reynolds' number is determined based on ratios of said velocities along different measuring paths.
26. The method according to claim 24, wherein the Reynolds' number is determined based on subtractions of the velocities along different measuring paths.
27. An ultrasound method of measuring the rate of flow of a flowing medium, using a measuring tube and at least two pairs of ultrasound transducers arranged on the measuring tube forming a measuring path, in which the rate of flow of the flowing medium is determined from the velocities of the medium along at least two measuring paths, wherein the Reynolds' number of the flowing medium is measured continuously and the value for the rate of flow is corrected using the value for the Reynolds' number, wherein in a calibration process, calibration flow profiles that are as undisturbed as possible are recorded from the velocities of the medium along the measuring paths for various rates of flow and Reynolds' numbers.
28. The method according to claim 27, wherein the viscosity of the medium is determined using the rate of flow, the diameter of the measuring tube and the
Reynolds' number.
29. The method according to claim 28, wherein the medium is identified using the viscosity and particularly other medium-dependent measured variables.
30. The method according to claim 29, wherein the ultrasound velocity and/or the ultrasound damping of the medium are determined as another medium-dependent measured variable.
31. The method according to claim 27, wherein the rate of flow is corrected using the value for the Reynolds' number and an error curve based on empirical data.
32. The method according to claim 27, wherein the Reynolds' number is determined using the velocities of the medium along at least two measuring paths.
33. The method according to claim 32, wherein the Reynolds' number is determined using an arithmetical algorithm from the velocities of the medium along different measuring paths.
34. The method according to claim 33, wherein the Reynolds' number is determined based on ratios of said velocities along different measuring paths.
35. The method according to claim 33, wherein the Reynolds' number is determined based on subtractions of the velocities along different measuring paths.
36. The method according to claim 27, wherein in a calibration process, at least one operating flow profile is recorded with the help of a device mounted and ready to operate that uses the method according to any one of claims 27 to 35.
37. The method according to claim 36, wherein deviations between the calibration flow profiles and the operating flow profiles are corrected arithmetically.
38. The method according to claim 37, wherein for Reynolds' numbers greater than 100,000, to record the operating flow profile, rates of flow for the medium are set that correspond as much as possible to the rates of flow when the calibration flow profile is recorded, wherein the ratios between the individual velocities along the measuring paths of the calibration flow profile and the operating flow profile are determined, wherein with these ratios, the current measured velocities along the measuring paths are corrected, and wherein that with this correction, the measured velocities are also corrected with the ratios of the rates of flow when the calibration flow profiles are recorded and when the reference flow profiles are recorded, preferably wherein the correction factors between the rates of flow set during the recording of the calibration flow profile and the operating flow profile are determined using interpolation.
39. The method according to claim 37, wherein especially for Reynolds' numbers smaller than 100,000, the calibration profiles are measured and stored in dimensionless form for a large number of Reynolds' numbers, wherein the current measured velocities and the current rate of flow for a dimensionless current flow profile are processed, and wherein the dimensionless current flow profile is compared with the calibration flow profiles and corrected by using said comparison.
40. The method according to claim 39, wherein: the Reynolds' number is zero approximation is determined from the current flow profile; the average velocity is determined from the flow profile stored for the
Reynolds' number in zero approximation; the average velocity from the memory is compared with the current average velocity, if there is a deviation between the average velocities above a predetermined limit, a new current average velocity is assumed that deviates less from the average velocity from the memory;
the Reynolds' number is determined in first approximation from the new currently determined velocity; the average velocity is determined again from the flow profile stored with the
Reynolds' number in first approximation; if there is a new deviation above the predetermined limit, a new current average velocity is again taken that deviates less from the average velocity from the memory; and otherwise, the last value for the Reynolds' number is used for further processing.
41. An ultrasound method of measuring the rate of flow of a flowing medium, using a measuring tube and at least two pairs of ultrasound transducers arranged on the measuring tube forming a measuring path, in which the rate of flow of the flowing medium is determined from the velocities of the medium along at least two measuring paths, wherein the Reynolds' number of the flowing medium is measured continuously and the value for the rate of flow is corrected using the value for the Reynolds' number, wherein the viscosity of the medium is determined using the rate of flow, the diameter of the measuring tube and the Reynolds' number.
42. An ultrasound method of measuring the rate of flow of a flowing medium, using a measuring tube and at least two pairs of ultrasound transducers arranged on the measuring tube forming a measuring path, in which the rate of flow of the flowing medium is determined from the velocities of the medium along at least two measuring paths, wherein the Reynolds' number of the flowing medium is measured continuously and the value for the rate of flow is corrected using the value for the Reynolds' number, wherein the viscosity of the medium is determined using the rate of flow, the diameter of the measuring tube and the Reynolds' number, and wherein the medium is identified using the viscosity and particularly other medium-dependent measured variables.
43. The method according to claim 42, wherein the ultrasound velocity and/or the ultrasound damping of the medium are determined as another medium dependent measured variable.
44. The method according to claim 41 or 42, wherein the rate of flow is corrected using the value for the Reynolds' number and an error curve based on empirical data.
45. The method according to claim 44, wherein the Reynolds' number is determined using the velocities of the medium along at least two measuring paths.
46. The method according to claim 45, wherein the Reynolds' number is determined using an arithmetical algorithm from the velocities of the medium along different measuring paths.
47. The method according to claim 46, wherein the Reynolds' number is determined based on ratios of said velocities along different measuring paths.
48. The method according to claim 46, wherein the Reynolds' number is determined based on subtractions of the velocities along different measuring paths.
49. A device for using the ultrasound method of measuring the rate of flow for a flowing medium, the method using a measuring tube and at least two pairs of ultrasound transducers arranged on the measuring tube forming a measuring path, in which the rate of flow of the flowing medium is determined from the velocities of the medium along at least two measuring paths, wherein the Reynolds' number of the flowing medium is measured continuously and the value for the rate of flow is corrected using the value for the
Reynolds' number, the device comprising a measuring tube, at least two pairs of ultrasound transducers arranged on the measuring tube and forming a measuring path, a transducer that determines the velocities of the medium along the measuring paths from the signals of the pair of ultrasound transducers, and an adder that determines the rate of flow of the medium from the velocities of the medium along the measuring paths, wherein the device comprises a Reynolds' number meter continuously finding the
Reynolds' number and a flow corrector connected to the Reynolds' number meter and the adder, wherein there are a profile corrector and a profile meter one after the other between the transducer and the adder, and wherein the profile corrector has a switch at the input, an
operating flow profile memory connected behind the switch, a flow profile comparer connected behind the operating flow profile memory, a profile transducer at the output, and a calibration flow profile memory connected with its input behind an output of the switch and its output in front of one input of the flow profile comparer, wherein another output of the flow profile comparer is connected to another input of the switch, and wherein if the calibration flow profile and the operating flow profile are not identical, the switch, the operating flow profile memory and the flow profile comparer form a feedback loop.
50. The device according to claim 49, wherein the Reynolds' number meter includes a turbulent-laminar switch, connected in parallel to the turbulent-laminar switch, a laminar flow meter, a turbulent flow meter, a transitional flow meter, and an output operation amplifier connected with the output of the laminar-flow meter, the turbulentflow meter and the transition-flow meter.
51. The device according to claim 49, wherein it has a viscosity meter connected to the output of Reynolds' number meter and the output of the flow corrector.
52. The device according to claim 51, characterized by the fact that a medium identifier connected to the output of the viscosity meter and to at least one input with outputs of the transducer is provided for identifying the type of medium by comparing the viscosity and the ultrasound velocity and/or the ultrasound damping with stored values, and the transducer determines the ultrasound velocity or the ultrasound damping.
53. A device for using the ultrasound method of measuring the rate of flow for a flowing medium, the method using a measuring tube and at least two pairs of ultrasound transducers arranged on the measuring tube forming a measuring path, in which the rate of flow of the flowing medium is determined from the velocities of the medium along at least two measuring paths, wherein the Reynolds' number of the flowing medium is measured continuously and the value for the rate of flow is corrected using the value for the
Reynolds' number, the device comprising a measuring tube, at least two pairs of
ultrasound transducers arranged on the measuring tube and forming a measuring path, a transducer that determines the velocities of the medium along the measuring paths from the signals of the pair of ultrasound transducers, and an adder that determines the rate of flow of the medium from the velocities of the medium along the measuring paths, wherein the device comprises a Reynolds' number meter continuously finding the
Reynolds' number and a flow corrector connected to the Reynolds' number meter and the adder, wherein the Reynolds' number meter includes a turbulent-laminar switch, connected in parallel to the turbulent-laminar switch, a laminar flow meter, a turbulent flow meter, a transitional flow meter, and an output operation amplifier connected with the output of the laminar-flow meter, the turbulent-flow meter and the transition-flow meter.
54. The device according to claim 53, wherein it has a viscosity meter connected to the output of Reynolds' number meter and the output of the flow corrector.
55. The device according to claim 54, wherein a medium identifier connected to the output of the viscosity meter and to at least one input with outputs of the transducer is provided for identifying the type of medium by comparing the viscosity and the ultrasound velocity and/or the ultrasound damping with stored values, and the transducer determines the ultrasound velocity or the ultrasound damping.