Noninvasive detection of corrosion, mic, and foreign objects in containers, using guided ultrasonic waves

• US 6,363,788 B1
• Filed: 07/11/2000
• Issued: 04/02/2002
• Est. Priority Date: 06/07/2000
• Status: Expired due to Term

• Current Assignee: Digital Wave Corporation (Hexagon Composites ASA)
• Original Assignee: Digital Wave Corporation (Hexagon Composites ASA)
• Inventors: Gorman, Michael R., Ziola, Steven M.
• Primary Examiner(s): Williams, Hezron
• Assistant Examiner(s): SAINT SURIN, JACQUES M
• Application Number:
  US09/613,705
• Time in Patent Office: 630 Days
• Field of Search: 735/70, 735/97, 735/99, 73/52, 735/87, 735/90, 732/90, 736/20, 736/22, 736/24, 736/43, 736/44, 735/98, 736/00
• US Class Current: 73/597
• CPC Class Codes: G01N 17/006 of metals
• CPC Class Codes: G01N 2291/011 Velocity or travel time
• CPC Class Codes: G01N 2291/015 Attenuation, scattering
• CPC Class Codes: G01N 2291/025 Change of phase or condition
• CPC Class Codes: G01N 2291/02854 Length, thickness
• CPC Class Codes: G01N 2291/0423 Surface waves, e.g. Rayleigh waves, Love waves
• CPC Class Codes: G01N 2291/0427 Flexural waves, plate waves, e.g. Lamb waves, tuning fork, cantilever
• CPC Class Codes: G01N 2291/044 Internal reflections (echoes), e.g. on walls or defects
• CPC Class Codes: G01N 2291/102 one emitter, one receiver
• CPC Class Codes: G01N 2291/2634 cylindrical from outside
• CPC Class Codes: G01N 2291/2695 Bottles, containers
• CPC Class Codes: G01N 29/041 on the surface of the material, e.g. using Lamb, Rayleigh or shear waves
• CPC Class Codes: G01N 29/348 with frequency characteristics, e.g. single frequency signals, chirp signals measuring frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04; measuring frequency or analysing frequency spectra G01R23/00
• CPC Class Codes: G01N 29/36 Detecting the response signal , e.g. electronic circuits specially adapted therefor

Abstract

Ultrasonic energy in the form of guided waves (plate waves or Lamb waves) is launched into the wall of a container. The guided wave propagates around the circumference of the container from a transmitting transducer to a receiving transducer. Analysis of the received waves determines the presence of corrosion pitting and MIC nodules on the container inner wall, as well as the existence of foreign objects in intimate contact with the container wall. The guided waves are created with wideband transducers excited at certain frequencies that depend on the material and geometry of the part being measured. The guided wave ultrasonic energy is maximized with a shaped tone burst pulse at the specified frequency rather than an electrical spike commonly used to excite transducers in standard ultrasonic search units. The energy and energy ratio of both the direct and wrap fields are measured and related to the container inner wall condition and the presence of any corrosion in the container or obstructions in intimate contact with the container wall.

Claims

1. A method for detecting container features, or materials attached to the container, by guided wrap wave ultrasound (GWWU), the method comprising:

(a.) placing a transmitting transducer and a receiving transducer at circumferential positions of a container;

(b.) generating guided waves using a shaped tone burst pulse at a specified frequency; and

,

(c.) measuring a direct field and/or wrap waves, thereby providing an indication of existence of corrosion and obstructions on the container inner wall, and foreign objects inside the container in contact with the container wall.

2. The method of claim 1, wherein the container comprises one or more of:

a dry pipe, a dry conduit, a dry tank, a dry barrel, a dry drum, a dry cylinder, and a dry plate.

3. The method of claim 1, wherein the container comprises one or more of:

a circular region, a conic region, and a cubic region.

4. The method of claim 1, wherein the container features, or materials attached to the container wall comprise one or more of:

corrosion on the inner wall of the container, MIC on the inner wall of the container, a foreign object attached to the inner wall and ice on the inner wall of the container.

5. The method of claim 4, wherein said corrosion comprises pitting or loss of wall material on the container inner wall.

6. The method of claim 4, wherein said MIC comprises microbiology-induced corrosion.

7. The method of claim 4, wherein said foreign objects is any slimy fluid or inner wall attachment.

8. The method of claim 1, wherein said transducer comprises a water-coupled wideband transducer, a dry-coupled wideband transducer, or an air-coupled wideband transducer.

9. The method of claim 1, wherein said guided waves are waves excited at a selected frequency and angle to maximize the direct field for selected container ODs and materials.

10. The method of claim 1, wherein said measuring includes recording and analyzing the direct field energy and wrap wave energy.

11. The method of claim 10, wherein the amplitude of a given phase point on the tone burst is selected or modulated.

12. The method of claim 1, wherein said direct field and/or wrap waves are the received signals due to guided wave propagation along the container.

24. The integrated system of claim 12, wherein the energy field detection module comprises an analog energy detector and an analog display.

13. An integrated system for detecting container features, or materials attached to the container, by guided wrap wave ultrasound (GWWU), the system comprising:

(a.) a transmitting transducer and a receiving transducer placed at circumferential positions of a container;

(b.) a guided wave generator which produces a shaped tone burst pulse at a specified frequency; and

,

(c.) an energy field detection module for measuring both a direct field and a wrap field, which measurement provides an indication of container features or materials inside the container.

14. The integrated system of claim 13, wherein the container comprises one or more of:

a dry pipe, a dry tank, a dry barrel, a dry drum, a dry cylinder, and a dry plate.

15. The integrated system of claim 13, wherein the container comprises one or more of:

a circular region, a conic region, and a cubic region.

16. The integrated system of claim 13, wherein the container features, or materials attached to the container wall comprise one or more of:

corrosion on the inner wall of the container, MIC on the inner wall of the container, a foreign object attached to the inner wall and ice on the inner wall of the container.

17. The integrated system of claim 13, comprising a computer or computer readable medium comprising an instruction set for controlling the transmitting transducer, or the guided wave generator.

18. The integrated system of claim 13, comprising a computer or computer readable medium comprising an instruction set for measuring the direct and wrap fields.

19. The integrated system of claim 13, comprising a computer or computer readable medium comprising an instruction set for measuring the direct and wrap fields and an additional instruction set for reporting the results of the measurement to a user.

20. The integrated system of claim 19, said instruction set comprising instructions for recording and analyzing the direct and wrap field energy.

21. The integrated system of claim 13, wherein said transducer comprises a water-coupled wideband transducer, a dry-coupled wideband transducer, or an air-coupled wideband transducer.

22. The integrated system of claim 13, wherein the energy field detection module comprises an analog to digital converter, which converter converts direct or leakage field energy into digital format data.

23. The integrated system of claim 22, the detection module comprising a digital display, which digital display provides a user-viewable display of information in the digital format data.

25. The integrated system of claim 13, the detection module comprising means for measuring the direct and leakage field.

26. A device for detecting container features, or materials attached to the container, by guided wrap wave ultrasound (GWWU), the device comprising:

(a.) a transmitting transducer and a receiving transducer configured to be placed at circumferential positions of a container;

(b.) a guided wave generator which produces a shaped tone burst pulse at a specified frequency; and

,

(d.) means for measuring a direct and wrap fields, thereby providing an indication of existence of corrosion and MIC on the container inner wall, and foreign objects inside the container in contact with the container wall.

27. The device of claim 26, wherein the container comprises one or more of:

a dry pipe, a dry tank, a dry barrel, a dry drum, a dry cylinder, and a dry plate.

28. The device of claim 26, wherein the container comprises one or more of:

a circular region, a conic region, and a cubic region.

29. The device of claim 26, wherein the container features, or materials attached to the containers comprise one or more of:

corrosion on the inner wall of the container, MIC on the inner wall of the container, ice on the inner wall of the container, or one or more foreign object or material attached to an inner wall of the container.

30. The device of claim 26, further comprising a computer or computer readable medium comprising an instruction set for measuring the direct and wrap fields and an additional instruction set for reporting the results of the measurement to a user.

31. The integrated system of claim 30, said instruction set comprising instructions for recording and analyzing the direct and wrap field energy.

32. The method of claim 31, wherein the amplitude of a given phase point on the tone burst is selected or modulated.

33. The device of claim 26, wherein said transducer comprises a water-coupled wideband transducer, a dry-coupled wideband transducer, or an air-coupled wideband transducer.

34. The device of claim 26, further comprising a computer with a plug-in arbitrary function generator and analysis/display software.

35. The device of claim 34 further comprising a 2-channel A/D converter.

36. The device of claim 34, wherein the arbitrary function generator generates a pulse at a user-defined frequency.

37. The device of claim 34, wherein the arbitrary function generator generates a pulse at a user-defined frequency and wherein an output of the arbitrary function generator is connected to a first channel input of the A/D converter.

38. The device of claim 26, further comprising a transmitting transducer coupling system, a receiving transducer coupling system, a RF amplifier, a RF receiver gain and filter circuitry, a computer with a plug-in arbitrary function generator, a 2-channel A/D converter, and an analysis/display software.

39. The device of claim 38, wherein the arbitrary function generator generates a pulse of user-defined frequency and wherein:

the output of the arbitrary function generator is connected to a first channel input of the A/D converter and to an input of the RF amplifier;

the RF amplifier output is connected to the transmitting transducer;

the receiving transducer is connected to an input of the RF receiver gain and filter circuitry;

the output of the RF receiver is connected to a second channel input of the A/D converter; and

,

the data analysis/display software controls signal generation, acquisition and display functions.