METHOD AND SYSTEM FOR NON-DESTRUCTIVE RAIL INSPECTION

• US 20170176389A1
• Filed: 02/11/2015
• Published: 06/22/2017
• Est. Priority Date: 02/11/2014
• Status: Abandoned Application

• Current Assignee: Pure Technologies Limited (Xylem, Inc.)
• Original Assignee: Pure Technologies Limited (Xylem, Inc.)
• Inventors: PAULSON, Peter O.
• Application Number:
  US15/118,022
• Publication Number:
  US 20170176389A1
• Time in Patent Office: Days
• CPC Class Codes: B61K 9/10 for detecting cracks in rails or welds thereof
• CPC Class Codes: B61L 23/044 Broken rails
• CPC Class Codes: G01N 27/82 for investigating the presence of flaws
• CPC Class Codes: G01R 33/022 Measuring gradient

Abstract

The present invention relates to a method for identifying and locating a defect in a metal rail, and includes the steps of positioning a first magnetic sensor at a distance above a rail, the first magnetic sensor being configured to measure a magnetic field of the rail; advancing the sensor along a length of the rail; sampling magnetic field measurements; determining multiple magnetic field gradients over different pluralities of samples; identifying a defect in the rail based on a change in one or more of the magnetic field gradients; and determining a position of the defect at a particular distance from the magnetic sensor based on a degree of variation in the magnetic field gradients.

Claims

1. A method for identifying and locating a defect in a metal rail, the method comprising:

positioning a first magnetic sensor at a distance above a rail, the first magnetic sensor being configured to measure a magnetic field of the rail;

advancing the sensor along a length of the rail;

sampling magnetic field measurements;

determining multiple magnetic field gradients over different pluralities of samples;

identifying a defect in the rail based on a change in one or more of the magnetic field gradients; and

determining a position of the defect at a particular distance from the magnetic sensor based on a degree of variation in the magnetic field gradients.

2. The method of claim 1 wherein the defect is determined to be at a greater distance from the magnetic sensor based on significant variations in the magnetic field gradients.

3. The method of claim 1 wherein the defect is determined to be at a distance close to the magnetic sensor based on minor variations in the magnetic field gradients.

4. The method of claim 1 wherein the defect is determined to be at the particular distance from the magnetic sensor corresponding to the largest magnetic field gradient, the position being approximately equal to a distance between samples used to determine that magnetic field gradient.

5. The method of claim 1 wherein a rate of sampling of the magnetic field measurements and a rate of advancing of the sensor are controlled to produce a 1 mm distance between each sample.

6. The method of claim 5 wherein determining multiple magnetic field gradients over different pluralities of samples comprises determining magnetic field gradients based on samples at intervals up to and including a distance corresponding to a height of the rail.

7. The method of claim 5 wherein determining multiple magnetic field gradients over different pluralities of samples comprises:

determining a first magnetic field gradient based on samples at 1 mm intervals; and

determining a second magnetic field gradient based on samples at 50, 100, 150 or 200 mm intervals.

8. The method of claim 1 wherein an axis of sensitivity of the magnetic sensor is positioned parallel to the length of the rail.

9. The method of claim 1 wherein an axis of sensitivity of the magnetic sensor is positioned transverse to the length of the rail.

10. The method of claim 1 further comprising:

positioning a second magnetic sensor laterally adjacent the first magnetic sensor, the first and second sensors spaced apart up to a distance greater than a width of the rail; and

determining the multiple magnetic field gradients over different pluralities of samples from each of the first and second sensor.

11. The method of claim 10 further comprising:

identifying the defect on either side of the longitudinal axis of the rail adjacent to the first or second magnetic sensor based on a change in the magnetic field gradients from the first or second sensor.

12. The method of claim 1 wherein positioning the first magnetic sensor comprises positioning a first array of magnetic sensors arranged in a first plane.

13. The method of claim 12 further comprising:

positioning a second array of magnetic sensors, in a second plane, the second plane displaced a vertical distance above the first plane.

14. The method of claim 13 wherein the vertical distance is 1 inch.

15. The method of claim 13 wherein each of the first and second arrays of sensors comprises between 8 to 16 magnetic sensors.

16. The method of claim 13 wherein each of the first and second arrays of sensors is configured to measure the magnetic field across the entire width of the rail.

17. The method of claim 1 wherein the distance above the rail is about 12.5 mm.

18. The method of claim 1 further comprising magnetizing the rail before sampling the magnetic field.

19. The method of claim 1 further comprising magnetizing the rail after sampling the magnetic field.

20. The method of claim 1 wherein positioning the first magnetic sensor comprises positioning the first magnetic sensor at the distance above the rail and adjacent to a wheel of a vehicle travelling along the rail, the first magnetic sensor being configured to measure the magnetic field of the rail under load of the vehicle travelling along the rail.

21. A system for identifying and locating a defect in a metal rail, the system comprising:

a moveable sensor configured to measure a magnetic field of a metal rail;

a processor; and

a non-transitory computer readable media having instructions stored thereon which when executed cause the processor to;

sample the magnetic field measurements;

determine multiple magnetic field gradients over different pluralities of samples;

identify a defect in the rail based on a change in one or more of the magnetic field gradients; and

determine a position of the defect at a particular distance from the sensor based on a degree of variation in the magnetic field gradients.

22. The system of claim 21 further comprising an optical encoder configured to determine a location of the sensor along the length of the rail.

23. The system of claim 21 further comprising a global positioning system (GPS) module configured to determine a location of the sensor along the length of the rail

24. The system of claim 21 further comprising a tracking system configured to adjust a distance between the moveable sensor and the rail.

25. The system of claim 22 wherein the system comprises

a computer comprising the processor and the non-transitory computer readable media;

and

a vehicle comprising the moveable sensor, the moveable sensor being in communication with the computer.

26. The system of claim 25 wherein the moveable sensor is in wireless communications with the computer.

27. The system of claim 21 wherein the moveable sensor forms a first array, the array comprising a plurality of sensors arranged on a single plane.

28. The system of claim 26 wherein the magnetic sensors form a first array, the first array comprising a plurality of sensors arranged on a single plane.

29. The system of claim 28 further comprising:

providing a second array of magnetic sensors, the second array displaced a vertical distance above the first array, preferably the vertical distance is 1 inch.

30. The system of claim 28 wherein the first array comprises between 8 to 16 sensors.

31. The system of claim 21 wherein an axis of sensitivity of the magnetic sensor is parallel to a length of the rail.

32. A non-transitory computer readable medium having instructions stored thereon for identifying a defect in a metal rail, the instructions when executed cause a computer to:

sample magnetic field measurements, the measurements obtained along a length of the rail, the measurements obtained from a magnetic sensor positioned a distance above the rail;

determine multiple magnetic field gradients over different pluralities of samples;

identify a defect in the rail based on a change in one or more of the magnetic field gradients; and

determine a position of the defect at a particular distance along a height of the rail based on a degree of variation in the magnetic field gradients.