Claims
- 1. A density meter for determining the density of at least one fluid within a pipe, said density meter comprising:
a first sound speed meter positioned at a first sensing region along said pipe which provides a first system effective sound speed signal; a second sound speed meter positioned at a second sensing region along said pipe which provides a second system effective sound speed signal; a signal processor, responsive to said first and said second system sound speed signals, which provides a density signal indicative of said density of said fluid pipe.
- 2. The apparatus of claim 1 wherein said first sensing region has a first cross sectional compliance and wherein said second sensing region has a second cross sectional compliance and wherein said first cross sectional compliance is substantially different from said second cross sectional compliance.
- 3. The apparatus of claim 1 wherein the compliance of said pipe is different in each of said sensing regions.
- 4. The apparatus of claim 1 further comprising a concentric shell positioned around each of said first and said second sound speed meters thereby isolating said first and said second sound meters from an outside environment.
- 5. The apparatus of claim 1, wherein said first and said second sound speed meters determine said first and said second system sound speeds from one-dimensional acoustic pressure waves traveling along said pipe.
- 6. The apparatus of claim 1 wherein said at least one of said first and said second sound speed meters comprises a fiber optic based sound speed meter.
- 7. The apparatus of claim 2 wherein said first or said second sensing region of said pipe comprises a non-circular cross sectional geometry.
- 8. The apparatus of claim 7 wherein said non-circular cross sectional geometry comprises an oval shape.
- 9. The apparatus of claim 2 further comprising an input line positioned between said first and said second sensing regions to provide a known quantity of a known substance into said fluid.
- 10. A method for measuring the density of a fluid within a pipe, the method comprising:
a) measuring a first effective system sound speed at a first sensing region along said pipe and providing a first effective system sound speed signal; b) measuring said a second effective system sound speed a second sensing region along said pipe and providing a second effective system sound speed signal; and c) calculating said density using said first and said second effective system sound speed signals.
- 11. The method of claim 10, wherein said calculating step (c) comprises:
d) subtracting said first and said second effective system sound speeds to obtain a difference related to a compliance difference between said two sensing regions.
- 12. The method of claim 10 wherein said measuring steps (a) and (b) comprise measuring a propagation velocity of a one-dimensional acoustic pressure wave traveling along said pipe.
- 13. The method of claim 10 wherein said step of measuring said first and said second effective system sound speeds comprises measuring a strain of the pipe.
CROSS REFERENCES TO RELATED APPLICATIONS
[0001] This application contains subject matter related to that disclosed in commonly owned co-pending U.S. patent applications, Ser. No., 09/344,094, entitled “Fluid Parameter Measurement in Pipes Using Acoustic Pressures”, filed Jun. 25, 1999, 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.