Ultrasonic flow meter system

1. An ultrasonic flow meter system comprising:

transducers arranged with respect to a conduit to define at least one chordal path through fluid flowing in the conduit;

at least one transmitting transducer and receiving transducer pair on the chordal path for generating a transit time signal;

at least one receiving transducer positioned to receive scattered energy from any angle from point locations in the fluid to generate a range gated Doppler signal;

a processing subsystem for exciting the at least one transmitting transducer and responsive to the transit time signal and the range gated Doppler signal and configured to generate a velocity profile and a mean velocity of the fluid flowing in the conduit;

in which the receiving transducers output transit time and Doppler shift signals to the processing subsystem;

in which the processing subsystem is configured to:

measure transit times of the transit time signals and determine a sound speed of the fluid;

calculate average velocity of the fluid along at least one transit time path using the measured transit times and the sound speed;

determine point locations in the fluid and measure point velocities at the point locations; and

in which the point locations are predetermined by using the sound speed.

2. The system of claim 1 in which the processing subsystem is configured to measure Doppler shift to compute velocity at the point locations.

3. The system of claim 2 in which the processing subsystem is configured to generate a velocity profile from the velocities at the point locations.

4. The system of claim 3 in which the velocity profile is a three-dimensional velocity profile.

5. The system of claim 3 in which the processing subsystem is configured to correct the average velocity of the fluid along the at least one transit time path to determine mean flow rate.

6. The system of claim 5 in which the processing subsystem is configured to correct the average velocity of the fluid along the at least one transit time path using the velocity profile.

7. The system of claim 5 further including means for displaying the mean flow rate.

8. An ultrasonic flow meter system comprising:

two transmitting transducer and receiving transducer pairs arranged with respect to a conduit to define two chordal paths through fluid flowing in the conduit;

at least one transmitting transducer and receiving transducer pair arranged on the conduit to define a diameter path and for generating a transit time signal;

at least one receiving transducer positioned to receive scattered energy from any angle from point locations in the fluid to generate a range gated Doppler signal;

a processing subsystem for exciting the transmitting transducer and responsive to the transit time signal and the range gated Doppler signal;

said processing subsystem being configured to:

measure transit time of the transit time signal and determine a sound speed of the fluid;

calculate average velocity of the fluid along at least one transit time path using the measured transit time and the sound speed;

predetermine the point locations in the fluid and measure point velocities at the point locations;

measure Doppler shift to compute velocity at the point locations;

generate a velocity profile from the velocities at the point locations; and

correct the average velocity of the fluid along the at least one transit time path to determine mean flow rate.

9. The system of claim 8 in which the average velocity of the fluid is calculated using the measured transit time and sound speed.

10. The system of claim 8 in which the point locations are determined using the sound speed.

11. The system of claim 8 in which the average velocity of the fluid along the at least one transit time path is corrected using the velocity profile.

12. The system of claim 8 in which the velocity profile is a three-dimensional profile.

13. An ultrasonic flow meter method comprising:

arranging transducers with respect to a conduit to define at least one chordal path through fluid flowing in the conduit;

generating a transit time signal from at least one transmitting transducer and receiving transducer pair on the chordal path;

generating a range gated Doppler signal from at least one receiving transducer positioned to receive scattered energy from any angle from point locations in the fluid;

exciting the transmitting transducer;

generating a velocity profile and a mean velocity of the fluid flowing in the conduit from the transit time signal and the range gated Doppler signal;

in which the receiving transducers output transit time and Doppler shift signals;

measuring transit time of the transit time signal and determining a sound speed of the fluid;

calculating average velocity of the fluid along at least one transit time path;

calculating the average velocity of the fluid using the measured transit time and the sound speed;

determining point locations in the fluid and measuring point velocities at the point locations; and

predetermining the point locations by using the sound speed.

14. The method of claim 13 including measuring Doppler shift to compute velocity at the point locations.

15. The method of claim 14 including generating a velocity profile from the velocities at the point locations.

16. The method of claim 15 in which the velocity profile is a three-dimensional velocity profile.

17. The method of claim 15 including correcting the average velocity of the fluid along the at least one transit time path and determining mean flow rate.

18. The method of claim 17 including correcting the average velocity of the fluid along the at least one transit time path using the velocity profile.

19. The method of claim 17 further including means for displaying the mean flow rate.

20. The method of claim 19 further including means for displaying the sound speed of the fluid.

21. An ultrasonic flow meter method comprising:

arranging two transmitting transducer and receiving transducer pairs with respect to a conduit to define two chordal paths through fluid flowing in the conduit;

arranging at least one transmitting transducer and receiving transducer pair on the conduit to define a diameter path and for generating a transit time signal;

positioning at least one of the receiving transducers to receive scattered energy from any angle from point locations in the fluid to generate a range gated Doppler signal;

exciting the at least one transmitting transducer;

measuring transit time of the transit time signal and determining a sound speed of the fluid;

calculating average velocity of the fluid along at least one transit time path using the measured transit time and the sound speed;

predetermining the point locations in the fluid and measuring point velocities at the point locations;

measuring Doppler shift from the range gated Doppler signal to compute velocity at the point locations;

generating a velocity profile from the velocities at the point locations; and

correcting the average velocity of the fluid along the at least one transit time path and determining mean flow rate.

22. The method of claim 21 including calculating the average velocity of the fluid using the measured transit time and sound speed.

23. The method of claim 21 including predetermining the point locations using the sound speed.

24. The method of claim 21 including correcting the average velocity of the fluid along the at least one transit time path using the velocity profile.

25. The method of claim 21 in which the velocity profile is a three-dimensional profile.

26. An ultrasonic flow meter system comprising:

transducers arranged with respect to a conduit to define at least one chordal path through fluid flowing in the conduit;

at least one transmitting transducer on the chordal path for generating a transit time signal;

at least one receiving transducer positioned to receive scattered ultrasonic signal carrying Doppler information from any point locations in the fluid;

a processing subsystem responsive to the transit time signal and the scattered signal;

wherein the receiving transducers output transit time and the scattered Doppler shift signals to the processing subsystem;

the processing subsystem being configured to measure transit times of the transit time signals and determine a sound speed of the fluid and calculate average velocity of the fluid along at least one transit time path using the measured transit times the processing subsystem further configured to determine point locations in the fluid by using the sound speed of the fluid and perform ranged gated Doppler measurement to obtain flow profile of the conduit by measuring point velocities at the point locations;

wherein the average velocity of the fluid in the conduit is calculated using the calculated velocity and the flow profile.

27. The system of claim 26 in which the processing subsystem is configured to measure Doppler shift to compute velocity at the point locations.

28. The system of claim 27 in which the processing subsystem is configured to generate a velocity profile from the velocities at the point locations.

29. The system of claim 28 in which the velocity profile is a three-dimensional velocity profile.

30. The system of claim 28 in which the processing subsystem is configured to correct the average velocity of the fluid along the at least one transit time path to determine mean flow rate.

31. The system of claim 30 in which the processing subsystem is configured to correct the average velocity of the fluid along the at least one transit time path using the velocity profile.

32. The system of claim 30 further including means for displaying the mean flow rate.