VIBRATORY FLOW METER AND METHOD FOR CORRECTING FOR AN ENTRAINED PHASE IN A TWO-PHASE FLOW OF A FLOW MATERIAL

• US 20100170322A1
• Filed: 05/03/2007
• Published: 07/08/2010
• Est. Priority Date: 05/03/2007
• Status: Active Grant

• Current Assignee: Micro Motion Incorporated (Emerson Electric Company)
• Original Assignee: Mrico Motion Incorporated
• Inventors: Van Cleve, Craig Brainerd, Weinstein, Joel
• Granted Patent: US 8,448,491 B2
• Time in Patent Office: Days
• US Class Current: 73/1.160
• CPC Class Codes: G01F 1/74 Devices for measuring flow of a fluid or flow of a fluent solid material in suspension in another fluid
• CPC Class Codes: G01F 1/8413 means for influencing the flowmeter's motional or vibrational behaviour, e.g., conduit support or fixing means, or conduit attachments
• CPC Class Codes: G01F 1/8436 signal processing
• CPC Class Codes: G01F 1/8477 with multiple measuring conduits
• CPC Class Codes: G01F 15/024 involving digital counting

Abstract

A vibratory flow meter (100) for correcting for an entrained phase in a two-phase flow of a flow material is provided. The vibratory flow meter (100) includes a flow meter assembly (10) including a driver (104) and with the vibratory flow meter (100) being configured to generate a vibrational response for the flow material. The vibratory flow meter (100) further includes and meter electronics (20) coupled to the flow meter assembly (10) and receiving the vibrational response. The meter electronics (20) is configured to generate a measured two-phase density of the two-phase flow using the vibrational response, determine the computed drive power needed by a driver (104) of the flow meter assembly (10), and calculate a density compensation factor using a liquid density of a liquid component of the two-phase flow, an entrained phase density of an entrained phase component, the measured two-phase density, and the computed drive power.

Claims

1. A vibratory flow meter (100) for correcting for an entrained phase in a two-phase flow of a flow material, comprising a flow meter assembly (10) including a driver (104) and with the vibratory flow meter (100) being configured to generate a vibrational response for the flow material and further comprising meter electronics (20) coupled to the flow meter assembly (10) and receiving the vibrational response, with the vibratory flow meter (100) being characterized by:

the meter electronics (20) being configured to generate a measured two-phase density of the two-phase flow using the vibrational response, determine the computed drive power needed by a driver (104) of the flow meter assembly (10), and calculate a density compensation factor using a liquid density of a liquid component of the two-phase flow, an entrained phase density of an entrained component, the measured two-phase density, and the computed drive power.

2. The vibratory flow meter (100) of claim 1, with the meter electronics (20) being configured to multiply a drive voltage by a drive current in order to determine the computed drive power.

3. The vibratory flow meter (100) of claim 1, with the meter electronics (20) being configured to multiply a pickoff sensor voltage by a drive current in order to determine the computed drive power.

4. The vibratory flow meter (100) of claim 1, with the meter electronics (20) being configured to solve equation

5. The vibratory flow meter (100) of claim 1, with calculating the density compensation factor comprising solving equation

6. The vibratory flow meter (100) of claim 1, with the meter electronics (20) being further configured to combine the density compensation factor with the measured two-phase density to provide a compensated two-phase density.

7. The vibratory flow meter (100) of claim 1, with the meter electronics (20) being further configured to combine the density compensation factor with the measured two-phase density to provide a compensated two-phase density, determine a predicted drive power using the liquid density, the entrained phase density, the compensated two-phase density, and a power characteristic of the vibratory flow meter (100), and determine an accuracy of flow measurements of the vibratory flow meter (100) based on a difference between the predicted drive power value and the computed drive power.

8. The vibratory flow meter (100) of claim 7, with the meter electronics (20) being further configured to solve the equation,

9. The vibratory flow meter (100) of claim 7, with determining the accuracy further comprising generating an alarm indication if the computed drive power differs from the predicted drive power by more than a predetermined tolerance.

10. The vibratory flow meter (100) of claim 7, with determining the accuracy further comprising generating an alarm indication if the computed drive power is greater than the predicted drive power by more than a predetermined upper threshold, indicating an excessive entrained phase level and further indicating a needed change in flow conditions in the vibratory flow meter.

11. The vibratory flow meter (100) of claim 7, with determining the accuracy further comprising generating an alarm indication if the computed drive power is greater than the predicted drive power by more than a predetermined upper threshold, indicating an excessive gas bubble size and further indicating a needed change in flow conditions in the vibratory flow meter.

12. The vibratory flow meter (100) of claim 7, with determining the accuracy further comprising generating an alarm indication if the computed drive power is greater than the predicted drive power by more than a predetermined upper threshold, indicating an excessive solid entrained phase level and further indicating a needed change in flow conditions in the vibratory flow meter.

13. The vibratory flow meter (100) of claim 7, with determining the accuracy further comprising generating an alarm indication if the computed drive power is greater than the predicted drive power by more than a predetermined upper threshold.

14. The vibratory flow meter (100) of claim 7, with determining the accuracy further comprising refining the compensated two-phase density if the computed drive power is less than the predicted drive power by more than a predetermined lower threshold or if the computed drive power is greater than the predicted drive power by more than a predetermined upper threshold.

15. The vibratory flow meter (100) of claim 14, with refining the compensated two-phase density comprising reducing the density compensation factor by an amount proportional to a difference between the computed drive power and the predetermined lower threshold.

16. The vibratory flow meter (100) of claim 7, with determining the accuracy further comprising comparing the predicted drive power to the computed drive power, generating an alarm indication if the computed drive power is greater than the predicted drive power by more than a predetermined upper threshold, and refining the compensated two-phase density by reducing the density compensation factor by an amount proportional to a difference between the computed drive power and the predetermined lower threshold if the computed drive power is less than the predicted drive power by more than a predetermined lower threshold.

17. A method of correcting for an entrained phase in a two-phase flow of a flow material in a vibratory flow meter, the method comprising generating a measured two-phase density of the two-phase flow, with the method being characterized by:

determining the computed drive power needed by a driver of the vibratory flow meter; and

calculating a density compensation factor using a liquid density of a liquid component of the two-phase flow, an entrained phase density of an entrained component, the measured two-phase density, and the computed drive power.

18. The method of claim 17, with determining the computed drive power comprising multiplying a drive voltage by a drive current.

19. The method of claim 17, with determining the computed drive power comprising multiplying a pickoff sensor voltage by a drive current.

20. The method of claim 17, with determining the computed drive power comprising solving equation

21. The method of claim 17, with calculating the density compensation factor comprising solving equation

22. The method of claim 17, further comprising combining the density compensation factor with the measured two-phase density to provide a compensated two-phase density.

23. The method of claim 17, further comprising:

combining the density compensation factor with the measured two-phase density to provide a compensated two-phase density;

determining a predicted drive power using the liquid density, the entrained phase density, the compensated two-phase density, and a power characteristic of the vibratory flow meter; and

determining an accuracy of flow measurements of the vibratory flow meter based on a difference between the predicted drive power value and the computed drive power.

24. The method of claim 23, further comprising solving the equation,

25. The method of claim 23, with determining the accuracy further comprising generating an alarm indication if the computed drive power differs from the predicted drive power by more than a predetermined tolerance.

26. The method of claim 23, with determining the accuracy further comprising generating an alarm indication if the computed drive power is greater than the predicted drive power by more than a predetermined upper threshold, indicating an excessive entrained phase level and further indicating a needed change in flow conditions in the vibratory flow meter.

27. The method of claim 23, with determining the accuracy further comprising generating an alarm indication if the computed drive power is greater than the predicted drive power by more than a predetermined upper threshold, indicating an excessive gas bubble size and further indicating a needed change in flow conditions in the vibratory flow meter.

28. The method of claim 23, with determining the accuracy further comprising generating an alarm indication if the computed drive power is greater than the predicted drive power by more than a predetermined upper threshold, indicating an excessive solid entrained phase level and further indicating a needed change in flow conditions in the vibratory flow meter.

29. The method of claim 23, with determining the accuracy further comprising generating an alarm indication if the computed drive power is greater than the predicted drive power by more than a predetermined upper threshold.

30. The method of claim 23, with determining the accuracy further comprising refining the compensated two-phase density if the computed drive power is less than the predicted drive power by more than a predetermined lower threshold or if the computed drive power is greater than the predicted drive power by more than a predetermined upper threshold.

31. The method of claim 30, with refining the compensated two-phase density comprising reducing the density compensation factor by an amount proportional to a difference between the computed drive power and the predetermined lower threshold.

32. The method of claim 23, with determining the accuracy further comprising:

comparing the predicted drive power to the computed drive power;

generating an alarm indication if the computed drive power exceeds the predicted drive power by more than a predetermined upper threshold; and

refining the compensated two-phase density by reducing the density compensation factor by an amount proportional to a difference between the computed drive power and the predetermined lower threshold if the computed drive power is less than the predicted drive power by more than a predetermined lower threshold.

33. A method of correcting for an entrained phase in a two-phase flow of a flow material in a vibratory flow meter, the method comprising generating a measured two-phase density of the two-phase flow, with the method being characterized by:

determining the computed drive power needed by a driver of the vibratory flow meter;

calculating a density compensation factor using a liquid density of a liquid component of the two-phase flow, an entrained phase density of an entrained component, the measured two-phase density, and the computed drive power;

combining the density compensation factor with the measured two-phase density to provide a compensated two-phase density;

determining a predicted drive power using the liquid density, the entrained phase density, the compensated two-phase density, and a power characteristic of the vibratory flow meter; and

determining an accuracy of flow measurements of the vibratory flow meter based on a difference between the predicted drive power value and the computed drive power.

34. The method of claim 33, with determining the computed drive power comprising multiplying a drive voltage by a drive current.

35. The method of claim 33, with determining the computed drive power comprising multiplying a pickoff sensor voltage by a drive current.

36. The method of claim 33, with determining the computed drive power comprising solving equation

37. The method of claim 33, with calculating the density compensation factor comprising solving equation

38. The method of claim 33, further comprising solving the equation,

39. The method of claim 33, with determining the accuracy further comprising generating an alarm indication if the computed drive power differs from the predicted drive power by more than a predetermined tolerance.

40. The method of claim 33, with determining the accuracy further comprising generating an alarm indication if the computed drive power is greater than the predicted drive power by more than a predetermined upper threshold, indicating an excessive entrained phase level and further indicating a needed change in flow conditions in the vibratory flow meter.

41. The method of claim 33, with determining the accuracy further comprising generating an alarm indication if the computed drive power is greater than the predicted drive power by more than a predetermined upper threshold, indicating an excessive gas bubble size and further indicating a needed change in flow conditions in the vibratory flow meter.

42. The method of claim 33, with determining the accuracy further comprising generating an alarm indication if the computed drive power is greater than the predicted drive power by more than a predetermined upper threshold, indicating an excessive solid entrained phase level and further indicating a needed change in flow conditions in the vibratory flow meter.

43. The method of claim 33, with determining the accuracy further comprising generating an alarm indication if the computed drive power is greater than the predicted drive power by more than a predetermined upper threshold.

44. The method of claim 33, with determining the accuracy further comprising refining the compensated two-phase density if the computed drive power is less than the predicted drive power by more than a predetermined lower threshold or if the computed drive power is greater than the predicted drive power by more than a predetermined upper threshold.

45. The method of claim 44, with refining the compensated two-phase density comprising reducing the density compensation factor by an amount proportional to a difference between the computed drive power and the predetermined lower threshold.

46. The method of claim 33, with determining the accuracy further comprising:

comparing the predicted drive power to the computed drive power;

generating an alarm indication if the computed drive power is greater than the predicted drive power by more than a predetermined upper threshold; and

refining the compensated two-phase density by reducing the density compensation factor by an amount proportional to a difference between the computed drive power and the predetermined lower threshold if the computed drive power is less than the predicted drive power by more than a predetermined lower threshold.