Apparatus and method for measuring multi-Phase flows in pulp and paper industry applications
View Patent ↗The consistency of a pulp slurry in a pipe 12 is determined using a pair of effective sound speeds a 1eff and a 2eff of the fluid/pipe system. The pair of effective system sound speed measurements are taken at two sensing regions X 1 , X 2 along the pipe wherein each of the sensing regions comprises a different system cross sectional area compliance. The pair of effective system sound speeds a 1eff and a 2eff are provided to signal processing logic 160 , which determines at least the composition of the fluid 12 flowing in the pipe 112 . The effective system sound speeds a 1eff and a 2eff may be provided by a pair of sound speed meters positioned at sensing regions X 1 , X 2 wherein the sound speed meters utilize a spatial array of acoustic pressure sensors placed at predetermined axial locations along the pipe 112 . One technique uses acoustic spatial array signal processing techniques with the direction of propagation of the acoustic signals along the longitudinal axis of the pipe 112.
1. A meter for determining the mass ratio of the solids of a multi-phase mixture flowing through a pipe, said meter comprising:
a first meter that measures the speed of sound propagating through the multi-phase mixture at a first sensing region along said pipe which provides a first effective sound speed signal;
a second meter that measures the speed of sound propagating through the multi-phase mixture at a second sensing region along said pipe which provides a second effective sound speed signal;
wherein said first sensing region along the pipe has a first compliance and said second sensing region along the pipe has a second compliance, and wherein said first compliance is different from said second compliance to change the speed of sound from the first sensing region to the second sensing region; and
a signal processor, responsive to the difference of said first and said second effective sound speed signals, that determines a parameter signal indicative of the mass ratio of solids of the multi-phase mixture within the pipe.
2. The meter of claim 1 , wherein said first and said second meters determine said first and said second effective sound speeds from acoustic pressure waves traveling axially through the multi-phase mixture flowing within the pipe.
3. The meter of claim 2 , wherein the acoustic pressure waves are provided by a passive acoustic source.
4. The meter of claim 2 , wherein the acoustic pressure waves are one dimensional.
5. The meter of claim 2 , wherein the acoustic pressure waves are inherently provided by the multi-phase mixture flowing through the pipe.
6. The meter of claim 1 , wherein the multi-phase mixture has at least three components, wherein one of the components is a gas.
7. The meter of claim 6 , wherein the signal processor determines the phase fraction of pulp of a pulp slurry having entrained gas.
8. The meter of claim 1 , wherein said first and said second sensing region of said pipe comprises different cross sectional geometry.
9. The meter of claim 8 , wherein at least one of said cross sectional geometry comprises a non-circular cross sectional geometry.
10. The meter of claim 1 , wherein the pipe at the first and second sensing regions have different cross sectional area compliance.
11. The meter of claim 1 , wherein the thickness of the wall of the first and second sensing regions of the pipe are different.
12. The meter of claim 1 , wherein one of the first and second sensing regions of the pipe is lined to provide different compliances.
13. The meter of claim 1 , wherein the first meter includes a first array of sensors for measuring acoustic pressure waves propagating through the multi-phase mixture, and wherein the second meter includes a second array of sensors for measuring acoustic pressure waves propagating through the multi-phase mixture.
14. The meter of claim 13 further comprising at least one concentric shell positioned around at least one of said first and said second array of sensors thereby acoustically isolating said first and second array of sensors from an outside environment.
15. The meter of claim 13 , wherein the sensors are disposed on the exterior of the pipe.
16. A meter for determining the mass ratio of solids of a multi-phase mixture flowing through a pipe, said meter comprising:
a first meter that measures the speed of acoustic pressure waves propagating through the multi-phase mixture at a first sensing region along said pipe which provides first sensed acoustic pressure signals;
a second meter that measures the speed of the acoustic pressure waves propagating through the multi-phase mixture at a second sensing region along said pipe which provides second sensed acoustic pressure signals;
wherein said first sensing region along the pipe has a first compliance and said second sensing region along the pipe has a second compliance, and wherein said first compliance is different from said second compliance to change the speed of sound from the first sensing region to the second sensing region; and
a signal processor, responsive to said first and said second sensed acoustic pressure signals, that determines the difference between a first effective sound speed signal and a second effective sound speed signal to determine a parameter signal indicative of the mass ratio of solids of the multi-phase mixture.
17. The meter of claim 16 , wherein the multi-phase mixture has at least three components, wherein one of the components is a gas.
18. The meter of claim 17 , wherein the signal processor determines the phase fraction of pulp of a pulp slurry having entrained gas.
19. The meter of claim 16 , wherein the signal processor determines said first and said second effective sound speeds from acoustic pressure waves traveling axially through the multi-phase mixture flowing within the pipe.
20. The meter of claim 19 , wherein the acoustic pressure waves are one dimensional.
21. The meter of claim 19 , wherein the acoustic pressure waves are inherently provided by the multi-phase mixture flowing through the pipe.
22. The meter of claim 16 , wherein said first and said second sensing regions of said pipe comprises different cross sectional geometry.
23. The meter of claim 22 , wherein at least one of said cross sectional geometry comprises a non-circular cross sectional geometry.
24. The meter of claim 16 , wherein the pipe at the first and second sensing regions have different cross sectional area compliance.
25. The meter of claim 16 , wherein the thickness of the wall of the first and second sensing regions of the pipe are different.
26. The meter claim 24 , wherein one of the first and second sensing regions of the pipe is lined.
27. The meter of claim 16 , wherein the acoustic pressure waves are provided by a passive acoustic source.
28. The meter of claim 27 , wherein the sensors are disposed on the exterior of the pipe.
29. A method for measuring the mass ratio of solids of a multi-phase mixture propagating through a pipe; the method comprising:
measuring a first effective sound speed at a first sensing region along said pipe and providing a first effective sound speed signal;
measuring said a second effective sound speed at a second sensing region along said pipe and providing a second effective sound speed signal;
wherein said first sensing region along the pipe has a first compliance and said second sensing region along the pipe has a second compliance, and wherein said first compliance is different from said second compliance to change the speed of sound from the first sensing region to the second sensing region;
determining a differential signal indicative of the difference between the first effective sound speed signal and the second effective sound speed signal; and
determining a parameter signal indicative of said mass ratio of solids in response to the differential signal.
30. The method of claim 29 , wherein the multi-phase mixture has at least three components, wherein one component is a gas.
31. The method of claim 30 , wherein the mass ratio of pulp of a pulp slurry having entrained gas is determined.
32. The method of claim 29 , wherein said first and said second meters determine said first and said second effective sound speeds from acoustic pressure waves traveling axially through the multi-phase mixture flowing within the pipe.
33. The method of claim 32 , wherein the acoustic pressure waves are one dimensional.
34. The method of claim 32 , wherein the acoustic pressure waves are inherently provided by the multi-phase mixture flowing through the pipe.
35. The method of claim 29 , wherein said steps of measuring said first and said second effective sound speeds comprises measuring a strain of the pipe.
36. The method of claim 29 , wherein the cross sectional shape of the first and second sensing regions are different.
37. The method of claim 29 , wherein the thickness of the wall of the first and second sensing regions of the pipe are different.
38. The method of claim 29 , wherein the measuring the first effective sound speed includes:
measuring acoustic pressure waves propagating through the multi-phase mixture using a first array of pressure sensors; and
wherein the measuring the second effective sound speed includes:
measuring acoustic pressure waves propagating through the multi-phase mixture using a second array of pressure sensors.