Claims
- 1. An apparatus for industrial sensing applications for measuring at least one parameter of a mixture of at least one fluid in a pipe in an industrial fluid process, comprising:
a spatial array of at least two pressure sensors, disposed at different axial locations along the pipe, and each measuring an acoustic pressure associated with a background acoustic noise source within the pipe at a corresponding axial location, each of said sensors providing an acoustic pressure signal indicative of the background acoustic noise within the pipe at said axial location of a corresponding one of said sensors; and a signal processor, responsive to said pressure signals, which provides a signal indicative of a speed of sound of the mixture in the pipe.
- 2. The apparatus of claim 1 wherein said signal processor comprises logic which calculates a speed at which sound propagates along said spatial array.
- 3. The apparatus of claim 1 wherein said signal processor comprises logic which calculates a frequency based signal for each of said acoustic pressure signals.
- 4. The apparatus of claim 2 wherein said acoustic pressure signals each comprise a frequency based signal and wherein said signal processor comprises logic which calculates a ratio of two of said frequency based signals.
- 5. The apparatus of claim 1 comprising at least three of said sensors.
- 6. The apparatus of claim 1 comprising three of said sensors and wherein said signal processor comprises logic which simultaneously solves the following equations for said speed of sound:
- 7. The apparatus of claim 1 wherein said signal processor calculates said speed of sound of said mixture using the following relation:
- 8. The apparatus of claim 1 wherein said sensors are equally spaced, a Mach number of the mixture is small compared to one, and said signal processor calculates the speed of sound of the mixture using the following relation:
- 9. The apparatus of claim 1 wherein said sensors are equally axially spaced, a Mach number of the mixture is small compared to one, and said signal processor calculates the speed of sound of the mixture using the following relation:
- 10. The apparatus of claim 1 wherein the signal processor comprises logic which calculates a fluid composition of the mixture in the pipe.
- 11. The apparatus of claim 1 wherein said signal processor comprises logic which calculates a fluid composition of the mixture using the following relation:
- 12. The apparatus of claim 1 wherein said speed of sound is substantially determined by two fluids within the mixture.
- 13. The apparatus of claim 1 wherein said pressure sensors are fiber optic pressure sensors.
- 14. The apparatus of claim 1 wherein at least one of said pressure sensors measures a circumference-averaged pressure at said axial location of said sensor.
- 15. The apparatus of claim 1 wherein at least one of said pressure sensors measures pressure at more than one point around a circumference of the pipe said given axial location of said sensor.
- 16. The apparatus of claim 1 wherein at least one of said pressure sensors measures strain on the pipe.
- 17. A method for measuring at least one parameter of a mixture of at least one fluid in a pipe in an industrial fluid process, said method comprising:
measuring acoustic pressures within the pipe at at least two predetermined axial measurement locations along the pipe; and calculating a speed of sound of the mixture using said acoustic pressure measured at said axial measurement locations.
- 18. The method of claim 17 wherein said calculating step comprises calculating a speed at which sound propagates along said axial measurement locations.
- 19. The method of claim 17 wherein said calculating step comprises calculating a frequency based signals for said acoustic pressures.
- 20. The method of claim 17 wherein said calculating step comprises calculating a ratio of two of said frequency based signals.
- 21. The method of claim 17 wherein said measuring step comprises measuring acoustic pressure at at least three axial measurement locations along the pipe.
- 22. The method of claim 17 wherein said measuring step comprises measuring acoustic pressure at three axial measurement locations along the pipe and wherein said calculating step comprises simultaneously solving the following equations for the speed of sound:
- 23. The method of claim 17 wherein said calculating step calculates said speed of sound of the mixture using the following relation:
- 24. The method of claim 17 wherein said measurement locations are equally axially spaced, a Mach number of the mixture is small, and said calculating step calculates the speed of sound of the mixture using the following relation:
- 25. The method of claim 17 wherein said measurement locations are equally axially spaced, a Mach number of the mixture is small compared to one, and said calculating step calculates the speed of sound of the mixture using the following relation:
- 26. The method of claim 17 further comprising calculating a fluid composition of the mixture in the pipe.
- 27. The apparatus of claim 17 further comprising calculating a fluid composition of the mixture using the following relation:
- 28. The method of claim 17 wherein the speed of sound is substantially determined by two fluids within the mixture.
- 29. The method of claim 28 wherein said two fluids are: oil/water, oil/gas, or water/gas.
- 30. The method of claim 17 wherein said measuring step is performed by fiber optic pressure sensors.
- 31. The method of claim 17 wherein said measuring step is performed by fiber optic Bragg grating-based pressure sensors.
- 32. The method of claim 17 wherein said measuring step measures a circumference-averaged pressure at said axial location of said sensor.
- 33. The method of claim 17 wherein said measuring step measures pressure at more than one point around a circumference of the pipe at said axial location of said sensor.
- 34. An industrial process control system for controlling at least one parameter of an industrial fluid process, said system comprising:
a pipe having at least one fluid flowing therein; an apparatus for measuring at least one parameter of a mixture of said at least one fluid, said apparatus comprising:
a spatial array of at least two pressure sensors, disposed at different axial locations along said pipe, and each measuring an acoustic pressure associated with a background acoustic noise source within said pipe at a corresponding axial location, each of said sensors providing an acoustic pressure signal indicative of the background acoustic noise within said pipe at said axial location of a corresponding one of said sensors; and a signal processor, responsive to said pressure signals, which provides an output signal indicative of a speed of sound of the mixture in the pipe; and a control device receiving said output signal and capable of controlling said process parameter to a predetermined level.
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is an continuation-in-part of commonly owned co-pending U.S. patent application, Ser. No., 09/344,094, entitled “Fluid Parameter Measurement in Pipes Using Acoustic Pressures”, filed Jun. 25, 1999, which is a continuation-in part of Ser. No., 09/105,534, entitled “Fluid Parameter Measurement in Pipes Using Acoustic Pressures”, filed Jun. 26, 1998, now abandoned and contains subject matter related to that disclosed in commonly owned co-pending U.S. patent applications: Ser. No. 09/344,070, entitled “Measurement of Propagating Acoustic Waves in Compliant Pipes”, filed Jun. 25, 1999, Ser. No. 09/344,069, entitled “Displacement Based Pressure Sensor Measuring Unsteady Pressure in a Pipe”, filed Jun. 25, 1999 and Ser. No. 09/344,093, entitled “Non-Intrusive Fiber Optic Pressure Sensor for Measuring Unsteady Pressures within a Pipe”, filed Jun. 25, 1999, all of which are incorporated herein by reference.
Continuation in Parts (2)
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Number |
Date |
Country |
Parent |
09344094 |
Jun 1999 |
US |
Child |
10007749 |
Nov 2001 |
US |
Parent |
09105534 |
Jun 1998 |
US |
Child |
09344094 |
Jun 1999 |
US |