Ultrasonic flow metering system

• US 6,487,916 B1
• Filed: 02/02/2000
• Issued: 12/03/2002
• Est. Priority Date: 02/02/2000
• Status: Expired due to Fees

• Current Assignee: Battelle Energy Alliance LLC (Battelle Memorial Institute)
• Original Assignee: Bechtel BWXT Idaho, LLC
• Inventors: Mauseth, Jason A., Gomm, Tyler J., Taylor, Steven C., Kraft, Nancy C., Phelps, Larry D.
• Primary Examiner(s): Fuller, Benjamin R.
• Assistant Examiner(s): ALLEN, ANDRE J
• Application Number:
  US09/496,787
• Time in Patent Office: 1,035 Days
• Field of Search: 738/61--619, 731/96
• US Class Current: 73/861.29
• CPC Class Codes: G01F 1/667 Arrangements of transducers for ultrasonic flowmeters; Circuits for operating ultrasonic flowmeters
• CPC Class Codes: G01F 1/86 Indirect mass flowmeters, e.g. measuring volume flow and density, temperature or pressure
• CPC Class Codes: G01N 2291/02818 Density, viscosity
• CPC Class Codes: G01N 2291/02836 Flow rate, liquid level
• CPC Class Codes: G01N 2291/056 Angular incidence, angular propagation
• CPC Class Codes: G01N 2291/103 one emitter, two or more receivers
• CPC Class Codes: G01N 2291/104 two or more emitters, one receiver
• CPC Class Codes: G01N 29/024 by measuring propagation velocity or propagation time of acoustic waves
• CPC Class Codes: G01N 29/4427 with stored values, e.g. threshold values

Abstract

A system for determining the density, flow velocity, and mass flow of a fluid comprising at least one sing-around circuit that determines the velocity of a signal in the fluid and that is correlatable to a database for the fluid. A system for determining flow velocity uses two of the inventive circuits with directional transmitters and receivers, one of which is set at an angle to the direction of flow that is different from the others.

Claims

1. A method for determining the flow velocity of a fluid comprising:

providing a fluid that flows in a given direction;

transmitting and receiving a first pulse perpendicular to said given direction across a first known distance within said fluid;

transmitting and receiving a second pulse at an oblique angle to said given direction, across a second known distance within said fluid;

determining respective velocities for said first and second pulses;

calculating the difference between said respective velocities;

using said difference to determine said flow velocity; and

comparing said flow velocity to a set-point flow velocity.

2. A method for determining the flow velocity of a fluid according to claim 1, wherein determining respective velocities for said first and second pulses comprises using a first sing-around circuit for said first pulse and a second sing-around circuit for said second pulse.

3. A method for determining the flow velocity of a fluid according to claim 1, wherein transmitting and receiving a second pulse is directed with an upstream directional component.

4. A method for determining the flow velocity of a fluid according to claim 1, wherein transmitting and receiving a second pulse is directed with a downstream directional component.

5. A method for determining the flow velocity of a fluid according to claim 1, wherein said fluid that flows is within a conduit.

6. A method for determining the flow velocity of a fluid according to claim 1, wherein transmitting and receiving comprises affixing a plurality of transmitters and respective receivers on said conduit.

7. A method for determining the flow velocity of a fluid according to claim 1, wherein transmitting and receiving comprises affixing a single transmitter and a plurality of receivers on said conduit.

8. A method of controlling a fluid flow system comprising:

providing a substantially linear conduit section having boundaries and a flowing fluid therein;

transmitting a first pulse perpendicular to said substantially linear conduit section between said boundaries across a first distance;

transmitting a second pulse at an oblique angle to said substantially linear conduit section between said boundaries across a second distance;

determining respective velocities for said first and second pulses through said fluid;

calculating the difference between said respective velocities;

using said difference to obtain a flow velocity;

comparing said flow velocity to a set-point flow velocity; and

optionally adjusting said flow velocity.

9. A method of controlling a fluid flow system according to claim 8, wherein transmitting comprises affixing a plurality of audio signal transmitters to said conduit and affixing a plurality of audio signal receivers to said conduit.

10. A method of controlling a fluid flow system according to claim 8, wherein said fluid flow system includes irrigation water.

11. A method of controlling a fluid flow system according to claim 8, wherein said fluid flow system includes a slurry.

12. A method of controlling a fluid flow system according to claim 8, wherein said fluid flow system includes a gas.

13. A method of controlling a fluid flow system according to claim 8, wherein said fluid flow system includes a combustion gas.

14. A method of controlling a fluid flow system according to claim 8, wherein said fluid flow system includes a plurality of sing-around circuits.

15. A system for measuring flow velocity of a fluid comprising:

a plurality of sing-around circuits, each said sing-around circuit including an acoustic transmitter, a receiver and a means for determining a settled sing-around frequency for each sing-around circuit, wherein said means for determining a settled sing-around frequency for each sing-around circuit comprises;

an amplifier in communication with said receiver;

a rectifier in communication with said amplifier; and

a gate circuit in communication with said rectifier; and

a means for calculating transit-time shift between at least two of said plurality of sing-around circuits, said means for calculating transit-time shift employing each said settled sing-around frequency.

16. A system for measuring flow of a fluid according to claim 15, further comprising a flowing fluid contained in a conduit.

17. A system for measuring flow of a fluid according to claim 16, wherein said flowing fluid contains water.

18. A system for measuring flow of a fluid according to claim 16, wherein said flowing fluid contains a slurry.

19. A system for measuring flow of a fluid according to claim 16, wherein said flowing fluid contains a gas.

20. A system for measuring flow of a fluid according to claim 16, further comprising an apparatus that employs said flowing fluid.

21. A system for measuring flow of a fluid according to claim 15, wherein said acoustic transmitter is ultrasonic.

22. A method of determining the percent solids of a slurry comprising:

providing a slurry in a conduit;

generating a pulse through said conduit across a known distance;

calculating the velocity of said pulse across said known distance; and

correlating said velocity to the percent solids in said slurry.

23. A method of determining the percent solids of a fluid according to claim 22, wherein correlating said velocity to the percent solids in said fluid comprises estimating the speed of sound for the fluid portion of said slurry.

24. A method of determining the percent solids of a fluid according to claim 22, wherein said pulse is generated by a sing-around circuit.

25. A method of determining the percent solids of a fluid according to claim 22, further comprising determining the flow velocity of said slurry.

26. A system for measuring the flow of a fluid comprising:

a first transmitter and a first receiver, said first transmitter and said first receiver being separated by a first distance;

a second transmitter and a second receiver, said second transmitter and said second receiver being separated by a second distance;

each of said first transmitter and receiver and said second transmitter and receiver comprising;

a trigger circuit including a signal rectifier;

means for determining the signal delay between said transmitter and said receiver, wherein said means for determining the signal delay between said transmitter and said receiver has an alternative digital signal filter connected to said trigger circuit; and

means for calculating the transit-time shift caused by the flow of said fluid.

27. A system for measuring the flow of a fluid according to claim 26, further comprising means for eliminating an errant signal generated by capacitive coupling between said transmitter and said receiver.

28. A system for measuring the flow of a fluid according to claim 26, wherein said trigger circuit further comprises:

a signal amplifier connected to said receiver;

said signal rectifier connected to said signal amplifier;

a signal converter connected to said signal rectifier; and

an alternative signal width adjuster connected to said signal converter.

29. A system for measuring the flow of a fluid according to claim 26, wherein said transmitter generates an audio signal in a frequency range from about 100 kHz to about 10 MHz.

30. A system for measuring the flow of a fluid according to claim 26, wherein said transmitter generates an audio signal with a frequency of about 1 MHz.

31. A system for measuring the flow of a fluid according to claim 26, wherein said transmitter generates a pulse with an initial pulse width in a range from about 0.1 microseconds to about 5 microseconds.

32. A system for measuring the flow of a fluid according to claim 26, wherein said trigger circuit has a signal amplifier with a gain between about 100 and about 10,000.

33. A system for measuring the flow of a fluid according to claim 26, wherein said square wave trigger circuit generates a square wave signal with a width of about 10 microseconds.

34. A system for measuring the flow of a fluid according to claim 26, further comprising a keep-alive circuit disposed between said receiver and said transmitter, said keep-alive circuit having a timing window in a range from about 0.1 to about 20 milliseconds.

35. A system for measuring the flow of a fluid according to claim 26, wherein said second pulse has a potential in a range from about 60 volts to about 220 volts.

36. A system for measuring the flow of a fluid according to claim 26, wherein elapsed time for one cycling of said system is measurable in a range from about 0.1 kHz to about 100 kHz.

37. A system for measuring the flow of a fluid according to claim 26, wherein said trigger circuit further comprises:

a signal amplifier connected to said receiver;

a signal rectified connected to said signal amplifier;

a signal converter connected to said signal rectifier; and

a alternative signal width adjuster connected to said signal converter, wherein said transmitter generates an audio signal in a frequency range from about 100 kHz to about 10 MHz, wherein said transmitter generates an audio signal with an attenuation between said transmitter and said receiver in excess of about 50%, wherein said transmitter generates a pulse with an initial pulse width in a range from about 0.1 microseconds to about 5 microseconds, wherein said signal amplifier has a gain between about 100 and about 10,000, wherein said trigger circuit generates a square wave signal with a width of about 10 microseconds, wherein said pulse has a potential in a range from about 60 volts to about 220 volts, and wherein elapsed time for one cycling of said system is measurable in a range from about 0.1 kHz to about 100 kHz.

38. A method of controlling a dynamic fluid-supply system comprising:

providing a first transmitter and a first receiver separated by first fixed distance and with a fluid therebetween;

transmitting a first pulse from said first transmitter;

receiving said first pulse across said first fixed distance to create a first receiver signal;

creating a first trigger signal;

using said first trigger signal to transmit a repeat pulse from said first transmitter;

determining the signal delay between said first transmitting and first receiving;

providing a second transmitter and a second receiver, separated by a second fixed distance and with said fluid therebetween, wherein said second transmitter and said second receiver are configured at a non-perpendicular angle to flow of said fluid;

transmitting a second pulse from said second transmitter;

receiving said second pulse across said second fixed distance to create a second receiver signal;

creating a second trigger signal;

using said second trigger signal to transmit a repeat pulse from said second transmitter;

determining the signal delay between said transmitting and said receiving; and

determining the transit-time shift between said second transmitter and said second receiver.

39. A method of controlling a dynamic fluid-supply system according to claim 38, wherein said first transmitter and said second transmitter are an integral unit.

40. A method of controlling a dynamic fluid-supply system according to claim 38, wherein transmitting comprises generating an audio signal in a frequency range from about 100 kHz to about 10 MHz, wherein said first pulse and said second pulse experience an attenuation between said transmitter and said receiver in excess of about 50%, wherein said first pulse and said second pulse each have an initial pulse width in a range from about 0.1 microseconds to about 5 microseconds, wherein said receiver signal is amplified for a gain between about 100 and about 10,000, wherein said receiver signal is converted into a square wave trigger signal with a width of about 10 microseconds, wherein said second pulse is generated from a source that has a potential in a range from about 60 volts to about 220 volts, and wherein elapsed time between said first pulse and second pulse is measurable in a range from about 0.1 kHz to about 100 kHz.

41. A method suitable for determining at least one flow parameter of a fluid having a direction of flow, the method comprising:

transmitting a first pulse through at least a portion of the fluid and across a first known distance, said first pulse traveling in a first orientation with respect to the direction of flow;

receiving said first pulse;

transmitting a second pulse through at least a portion of the fluid and across a second known distance, said second pulse traveling in second orientation with respect to the direction of flow;

receiving said second pulse;

measuring a Doppler shift between said first pulse and said second pulse; and

determining a velocity of the flow based at least in part upon said Doppler shift.

42. The method as recited in claim 41, wherein said transmitting a first pulse through at least a portion of the fluid and across a first known distance, said first pulse traveling in a first orientation with respect to the direction of flow comprises transmitting a first pulse through at least a portion of the fluid and across a first known distance, said first pulse traveling in a direction substantially perpendicular to the direction of flow.

43. The method as recited in claim 41, wherein said transmitting a second pulse through at least a portion of the fluid and across a second known distance, said second pulse traveling in second orientation with respect to the direction of flow comprises transmitting a second pulse through at least a portion of the fluid and across a second known distance, said second pulse traveling in a direction oblique to the direction of flow.

44. The method as recited in claim 41, further comprising correlating said velocity of the flow to a percentage of solids present in the flow.

45. The method as recited in claim 41, wherein measuring a Doppler shift facilitates determination of velocities of said first and second pulses.

46. The method as recited in claim 45, wherein determining a velocity of the flow based at least in part upon said Doppler shift comprises calculating a difference between said velocities of said first and second pulses and using said difference to facilitate determination of said velocity of the flow.

47. The method as recited in claim 41, wherein determining a velocity of the flow based at least in part upon said Doppler shift is achieved using the equation:

$=\frac{\left(d_1<br><br>J_1-d_0<br><br>J_0\right)}{\cos <br><br>\left({\mathrm{\Theta <br><br>}}_1\right)}$

wherein,

V_f is said velocity of the flow;

d₀ is said first known distance;

d₁ is said second known distance;

f₀ is a frequency of said first pulse;

f₁ is a frequency of said second pulse; and

cosine Θ

₁ is a cosine of an angle cooperatively defined by said second orientation and the direction of flow of the fluid.

48. The method as recited in claim 41, wherein at least one of said first pulse and said second pulse is in a frequency range of about 100 kHz to about 10 mHz.

49. The method as recited in claim 41, wherein at least one of said first pulse and said second pulse has a frequency of about 1 mHz.

50. The method as recited in claim 41, wherein at least one of said first pulse and said second pulse has an initial pulse width in a range of about 0.1 microseconds to about 5.0 microseconds.

51. The method as recited in claim 41, wherein at least one of said first pulse and said second pulse has a potential in a range of about 60 volts to about 220 volts.

52. In a fluid system including a conduit through which a fluid flows, a method suitable for managing flow in the fluid system, the method comprising:

transmitting a first pulse through at least a portion of the fluid and across a first known distance, said first pulse traveling in a first orientation with respect to the direction of flow;

receiving said first pulse;

transmitting a second pulse through at least a portion of the fluid and across a second known distance, said second pulse traveling in second orientation with respect to the direction of flow;

receiving said second pulse;

measuring a Doppler shift between said first pulse and said second pulse; and

determining a velocity of the flow based at least in part upon said Doppler shift;

comparing said velocity of the flow to a set-point velocity; and

optionally adjusting at least said velocity of the flow.

53. The method as recited in claim 52, wherein said first orientation comprises a direction substantially perpendicular to the direction of flow.

54. The method as recited in claim 52, wherein said second orientation comprises a direction oblique to the direction of flow.

55. The method as recited in claim 52, wherein measuring a Doppler shift facilitates determination of velocities of said first and second pulses.

56. The method as recited in claim 55, wherein determining a velocity of the flow based at least in part upon said Doppler shift comprises calculating a difference between said velocities of said first and second pulses and using said difference to facilitate determination of said velocity of the flow.

57. The method as recited in claim 52, wherein determining a velocity of the flow based at least in part upon said Doppler shift is achieved using the equation:

$=\frac{\left(d_1<br><br>J_1-d_0<br><br>J_0\right)}{\cos <br><br>\left({\mathrm{\Theta <br><br>}}_1\right)}$

wherein,

V_f is said velocity of the flow;

d₀ is said first known distance;

d₁ is said second known distance;

f₀ is a frequency of said first pulse;

f₁ is a frequency of said second pulse; and

cosine Θ

₁ is a cosine of an angle cooperatively defined by said second orientation and the direction of flow of the fluid.

58. A method suitable for determining the percent solids in a slurry containing a solid portion and a fluid portion, the method comprising:

generating a pulse;

transmitting said pulse through at least a portion of the slurry and across a first known distance;

calculating a velocity of said pulse; and

correlating said velocity to a percentage of solids present in said slurry.

59. The method as recited in claim 58, wherein correlating said velocity to a percentage of solids present in said slurry comprises estimating a speed of sound through the fluid portion of said slurry.

60. The method as recited in claim 58, further comprising determining a flow velocity of the slurry.