Device and method designed for ultrasonically inspecting cylinders for longitudinal and circumferential defects and to measure wall thickness

• US 6,851,319 B2
• Filed: 09/26/2001
• Issued: 02/08/2005
• Est. Priority Date: 09/27/2000
• 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., Miller, William J., Ziola, Steven M.
• Primary Examiner(s): CHAPMAN JR, JOHN E
• Application Number:
  US09/965,672
• Publication Number:
  US 20020078751A1
• Time in Patent Office: 1,231 Days
• Field of Search: 736/22, 736/20, 736/21, 736/37, 736/38, 73/52
• US Class Current: 73/622
• CPC Class Codes: G01B 17/02 for measuring thickness
• CPC Class Codes: G01N 2291/02854 Length, thickness
• CPC Class Codes: G01N 2291/044 Internal reflections (echoes), e.g. on walls or defects
• CPC Class Codes: G01N 2291/048 Transmission, i.e. analysed material between transmitter and receiver
• CPC Class Codes: G01N 2291/105 two or more emitters, two or more receivers
• CPC Class Codes: G01N 2291/2634 cylindrical from outside
• CPC Class Codes: G01N 29/0618 synchronised with scanning, e.g. in real-time
• CPC Class Codes: G01N 29/28 providing acoustic coupling , e.g. water impedance matching G10K11/02

Abstract

Methods and apparatus for ultrasonically scanning cylinders are provided. The methods and apparatus employ as few as one ultrasonic sensor for full immersion scanning and defect detection. Self-centering fixturing spins the cylinder, reducing vibration, allowing for fast ultrasonic scans. To create the 45 degree angle beam shear waves for the circumferential scans, the ultrasonic sensor is offset from the centerline of the cylinder, creating the correct angle for excitation of the shear wave.

Claims

1. A container defect detection apparatus, comprising:

a fluid tank;

a rotatable cup mounted within the fluid tank, which rotatable cup is configured to receive a first region of a container;

a rotatable cap configured to receive a second region of the container;

an engagement mechanism which moves the rotatable cup or rotatable cap towards or away from each other to engage the container;

a drive train coupled to the rotatable cup or the rotatable cap, which drive train turns the rotatable cup or rotatable cap; and

,

an adjustable receiving/transmitting transducer positioned to mount proximal to the container.

2. The container defect apparatus of claim 1, wherein the cup comprises a centering ring.

3. The container defect apparatus of claim 1, wherein the cap comprises a rubber collar.

4. The container defect apparatus of claim 1, the drive train comprising:

a motor mounted outside of the fluid tank, which motor is coupled to a gearbox, which gear box is coupled to an output shaft, which output shaft passes through a bearing housing mounted in a wall of the fluid tank and into contact with the cap.

5. The container defect apparatus of claim 1, wherein the rotatable cap is shaped to mount over a cylinder valve.

6. The container defect apparatus of claim 1, wherein the rotatable cup is coupled to a tailstock assembly which comprises the engagement mechanism.

7. The container defect apparatus of claim 1, wherein the rotatable cup is coupled to a tailstock assembly which comprises the engagement mechanism, which engagement mechanism comprises a pneumatic cylinder which moves the rotatable cup into engagement with the container.

8. The container defect apparatus of claim 1, wherein the engagement mechanism comprises a pneumatic cylinder.

9. The container defect apparatus of claim 1, wherein:

the rotatable cup is housed in a tailstock;

the engagement mechanism comprises a slide upon which the tailstock moves towards or away from the drive train; and

, the drive train is coupled to the rotatable cap.

10. The container defect apparatus of claim 1, comprising a receiving transducer display coupled to the receiving transducer, which display displays an output of the receiving/transmitting transducer.

11. The container defect apparatus of claim 10, wherein the display is a computer screen and wherein the receiving transducer is coupled to a computer, which computer comprises instructions for detecting one or more signal from the receiving transducer.

12. The container defect apparatus of claim 10, wherein the display is a computer screen and wherein the receiving transducer is coupled to a computer, which computer comprises instructions for moving the receiving/transmitting transducer.

13. The container defect apparatus of claim 10, wherein the display is a computer screen and wherein the receiving transducer is coupled to a computer, which computer comprises instructions for directing one or more signal outputs from the receiving/transmitting transducer.

14. The container defect apparatus of claim 1, wherein the receiving/transmitting transducer is positioned above or below the centerline of the container when the container is mounted in the apparatus, to provide a 45 degree shear wave as the search tube holder and transducer is moved along a longitudinal axis of the container.

15. The container defect apparatus of claim 1, wherein the receiving/transmitting transducer is mounted on a search tube holder that holds the transducer at an angle to provide a 45 degree shear wave as the search tube holder and transducer is moved along a longitudinal axis of the container, when the container is mounted in the apparatus.

16. The container defect apparatus of claim 1, wherein the receiving/transmitting transducer is positioned normal to the container, when the container is mounted in the apparatus to provide a longitudinal wave as the search tube holder and transducer is moved along a longitudinal axis of the container.

17. The container defect apparatus of claim 1, wherein the receiving/transmitting transducer is height or angle adjustable with respect to the container, when the container is mounted in the apparatus.

18. The container defect apparatus of claim 1, wherein the receiving/transmitting transducer is mounted on a search tube.

19. The container defect apparatus of claim 18, wherein the search tube is coupled to a rotatable search tube holder.

20. The container defect apparatus of claim 19, wherein the rotatable search tube holder is coupled to an x-y-z translation mechanism which comprises an x-axis linear table, an x-axis motor which drives the search tube holder along the x-axis linear table, and x-axis encoder which tracks motion of the search tube holder along the x-axis linear table, a y-axis linear table, a y-axis motor which drives the search tube holder along the y-axis linear table, a y-axis encoder which tracks motion of the search tube holder along the y-axis linear table, a z-axis linear table, a z-axis motor which drives the search tube holder along the z-axis linear table, and a z-axis encoder which tracks motion of the search tube holder along the z-axis.

21. The container defect apparatus of claim 1, wherein the receiving/transmitting transducer is a right angle transducer.

22. The container defect apparatus of claim 1, wherein the fluid tank is partly filled with water.

23. The container defect apparatus of claim 1, further comprising a container mounted between the rotatable cap and the rotatable cup.

24. The container defect apparatus of claim 23, wherein the container is a cylinder comprising a cylinder valve in the second region, wherein the rotatable cap is a drive collar shaped to mount over the cylinder valve.

25. The container defect apparatus of claim 1, wherein the apparatus is portable.

26. The container defect apparatus of claim 1, wherein the apparatus further comprises system software for aligning the transmitting transducer with respect to the container, when the container is mounted in the apparatus or for analyzing a signal from the transmitting/receiving transducer.