Apparatus having an array of piezoelectric film sensors for measuring parameters of a process flow within a pipe

• US 20040168523A1
• Filed: 11/12/2003
• Published: 09/02/2004
• Est. Priority Date: 11/12/2002
• Status: Abandoned Application

• Current Assignee: Cidra Sarl (Nordic Cultural & Educational Foundation)
• Original Assignee: Cidra Sarl (Nordic Cultural & Educational Foundation)
• Inventors: Kersey, Alan D., Fernald, Mark R., Bailey, Timothy J., Davis, Michael A., Loose, Douglas
• Application Number:
  US10/712,833
• Publication Number:
  US 20040168523A1
• Time in Patent Office: Days
• US Class Current: 73/861.01
• CPC Class Codes: G01F 1/666 by detecting noise and sounds generated by the flowing fluid
• CPC Class Codes: G01F 1/668 Compensating or correcting for variations in velocity of sound
• CPC Class Codes: G01F 1/7082 using acoustic detecting arrangements
• CPC Class Codes: G01F 1/712 using auto-correlation or cross-correlation detection means
• 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

Abstract

A apparatus 10,110,170 is provided that measures the speed of sound and/or vortical disturbances propagating in a single phase fluid flow and/or multiphase mixture to determine parameters, such as mixture quality, particle size, vapor/mass ratio, liquid/vapor ratio, mass flow rate, enthalpy and volumetric flow rate of the flow in a pipe, by measuring acoustic and/or dynamic pressures. The apparatus includes a spatial array of unsteady pressure sensors 15-18 placed at predetermined axial locations x₁-x_N disposed axially along the pipe 14. The pressure sensors 15-18 provide acoustic pressure signals P₁(t)-P_N(t) to a signal processing unit 30 which determines the speed of sound a_mix propagating through of the process flow 12 flowing in the pipe 14. The pressure sensors are piezoelectric film sensors that are mounted or clamped onto the outer surface of the pipe at the respective axial location.

Claims

1. An apparatus for measuring at least one parameter of a process flow flowing within a pipe, the apparatus comprising:

at least two pressure sensors clamped onto the outer surface of the pipe at different axial locations along the pipe, each of the pressure sensors providing a respective pressure signal indicative of a pressure disturbance within the pipe at a corresponding axial position, each of the pressure sensors comprising a piezoelectric film sensor; and

a signal processor, responsive to said pressure signals, which provides a signal indicative of at least one parameter of the process flow flowing within the pipe.

2. The apparatus of claim 1, wherein each of the pressure sensors further include a strap for attaching the piezoelectric film sensor thereto.

3. The apparatus of claim 1, wherein the process flow is one of a single phase fluid and a multi-phase mixture.

4. The apparatus of claim 2, wherein the piezoelectric film sensor is attached to the outer surface of the strap and/or the inner surface of the strap.

5. The apparatus of claim 2, wherein the strap is a metallic material.

6. The apparatus of claim 2, further includes a clamping device for attaching the ends of one of the pressure sensors to clamp the pressure sensor onto the pipe.

7. The apparatus of claim 2, wherein the pressure sensors are removably clamped to the pipe.

8. The apparatus of claim 2, wherein the pressure sensors are permanently clamped to the pipe.

9. The apparatus of claim 1, wherein the piezoelectric film sensor includes at least one of polyvinylchlorine fluoride (PDVF), polymer film and flexible PZT.

10. The apparatus of claim 1, wherein the piezoelectric film includes a pair of conductors disposed on opposing surfaces of the piezoelectric-film.

11. The apparatus of claim 10, wherein each the pair of conductors is a coating of silver ink.

12. The apparatus of claim 1, wherein the piezoelectric film extends around a substantial portion of the circumference of the pipe.

13. The apparatus of claim 1, wherein the piezoelectric film has a thickness greater than 8 mm.

14. The apparatus of claim 1, wherein the piezoelectric film has a thickness between 8 mm and 120 mm.

15. The apparatus of claim 1, further includes an electrical insulator between the piezoelectric film and the strap.

16. The apparatus of claim 1, wherein the pressure signals are indication of acoustic pressures propagating within the pipe.

17. The apparatus of claim 1, wherein the parameter of the fluid is one of steam quality or “

wetness”

, vapor/mass ratio, liquid/solid ratio, volumetric flow rate, mass flow rate, size of suspended particles, density, gas volume fraction, and enthalpy of the flow.

18. The apparatus of claim 1, wherein the signal processor determines the slope of an acoustic ridge in the k-w plane to determine a parameter of the process flow flowing in the pipe.

19. The apparatus of claim 1, wherein the pressure signals are indication of vortical disturbances within the fluid flow.

20. The apparatus of claim 19, wherein the parameter of the fluid is one of velocity of the process flow and the volumetric flow of the process fluid.

21. The apparatus of claim 1, wherein the signal processor determines the slope of a convective ridge in the k-w plane to determine the velocity of the fluid flowing in the pipe.

22. The apparatus of claim 1, wherein the signal processor determines the volumetric flow rate of the fluid flowing in the pipe in response to the velocity of the fluid.

23. The apparatus of claim 1, wherein the signal processor generates a flow velocity signal indicative of the velocity of the fluid flowing within the pipe by cross-correlating the pressure signals.

24. The apparatus of claim 1 wherein each sensor measures an acoustic pressure and provides a signal indicative of an acoustic noise within the pipe.

25. The apparatus of claim 1 further comprising at least three of said pressure sensors.

26. The apparatus of claim 1, wherein the pressure sensors are mounted to the outer surface of the pipe.

27. The apparatus of claim 26, wherein the pressure sensors are mounted to the outer surface of the pipe by an adhesive.