Compact X-ray fluorescence spectrometer for real-time wear metal analysis of lubrucating oils

• US 5,982,847 A
• Filed: 10/27/1997
• Issued: 11/09/1999
• Est. Priority Date: 10/28/1996
• Status: Expired due to Term

• Current Assignee: X-Ray Optical Systems Incorporated (Veralto Corp.)
• Original Assignee: Utah State University
• Inventors: Nelson, Irina
• Primary Examiner(s): Porta, David P.
• Application Number:
  US08/958,415
• Time in Patent Office: 743 Days
• Field of Search: 378/44, 378/45, 378/46, 378/47, 378/48, 378/49, 378/84, 378/85, 250/505.1
• US Class Current: 378/47
• CPC Class Codes: G01N 23/221 by activation analysis
• CPC Class Codes: G01N 33/2858 Metal particles

Abstract

A compact X-ray fluorescence spectrometer system dedicated to in-line, real-time analysis of wear metal particles in a lubricant used in a lubricating system that comprises a sample chamber, an X-ray source assembly, and an X-ray detector assembly. The sample chamber is substantially composed of a non-metallic material and has a cylindrical shape. The sample chamber is adapted for in-line connection to the lubrication system of the machine such that the sample chamber provides a passageway through which the lubricant flows. The sample chamber has an X-ray transparent window formed therein that allows the passage of X-rays so that the presence of wear metal particles can be detected in the lubricant. A high intensity, relatively small spot incident X-ray source assembly is configured to provide a source of X-rays directed toward the sample chamber such that said X-rays pass through the window in the sample chamber and contact the lubricant flowing therethrough. The X-ray source assembly may comprise either an electron-beam excited X-ray tube associated with a collimating/focusing assembly or, alternatively, an X-ray laser source. The X-ray detector assembly is configured to detect the X-rays emitted from the lubricant flowing through the sample chamber. The X-ray detector assembly generates a signal reflecting the X-rays emitted by the lubricant and comprises a collimating/focusing assembly capable of wide angle collection of the X-rays emitted from the lubricant flowing though the sample chamber and a low-noise X-ray detector. The system also includes a computer system and associated software for processing the signal in order to determine the presence and amount of wear metal particles in said lubricant.

Claims

1. An apparatus for measurement of wear metal particles in a lubricant of a lubrication system of a machine, said apparatus comprising:

(a) a sample chamber means for providing a chamber to measure the presence and amount of wear metal particles in said lubricant, said sample chamber means adapted for in-line connection into the lubrication system so that said sample chamber means provides a passageway through which the lubricant flows, at least a portion of said sample chamber means allowing passage of X-rays into and out of said sample chamber means so that the presence of wear metal particles can be detected in the lubricant;

(b) source means for providing a source of said X-rays directed toward said sample chamber means so that said X-rays pass through said sample chamber means and contact the lubricant, and metal particles that the lubricant may contain, flowing therethrough;

(c) detector means for detecting said X-rays emitted by the lubricants and by metal particles that may be contained therein, as the lubricant and metal particles flow through said sample chamber means, said detector means generating a signal representing a quantitative measure of said X-rays emitted by the lubricant and said X-rays emitted by the metal particles; and

(d) means for processing said signal in order to determine the presence and amount of wear metal particles in the lubricant, thereby providing real-time identification and measurement of wear metal particles in the lubricant.

2. A compact apparatus as recited in claim 1, wherein said sample chamber means comprises a tubular sample chamber configured for in-line connection to said lubrication system, said sample chamber having a longitudinal axis substantially parallel to the flow of said lubricant therethrough.

3. A compact apparatus as recited in claim 1, wherein the lubricant flow through said sample chamber is substantially vertical.

4. A compact apparatus as recited in claim 2, wherein said sample chamber is concentrically attached to the lubrication system.

5. A compact apparatus as recited in claim 1, wherein said portion of said sample chamber means allowing passage of said X-rays into and out of said sample chamber means comprises an X-ray transparent material.

6. A miniature apparatus as recited in claim 5, wherein said x-ray transparent material is selected from the group consisting of beryllium, coated beryllium, polyimides, boron, and aluminum-coated polymers.

7. A miniature apparatus as recited in claim 1, wherein said sample chamber means comprises material selected from the group consisting of light metals, nylon, bakelite, or other plastic materials.

8. A compact apparatus as recited in claim 1, wherein said source means comprises an electron-beam excited X-ray tube and a collimating/focusing assembly.

9. A compact apparatus as recited in claim 1, wherein said source means comprises an X-ray laser source capable of providing high intensity X-rays to said sample chamber means.

10. A compact apparatus as recited in claim 1, wherein said detector means comprises:

(a) an X-ray detector configured to detect said X-rays emitted by the lubricant flowing through said sample chamber means; and

(b) a collimating/focusing assembly configured to deliver collimated/focused X-rays emitted by the lubricant to said X-ray detector.

11. A compact apparatus as recited in claim 2, wherein said source means and said detector means are positioned on opposite sides of an x-axis formed through the center of said portion of said sample chamber allowing passage of X-rays into and out of said sample chamber, said x-axis being that is substantially perpendicular to said longitudinal axis of said sample chamber, said source means being positioned at an angle β

from said x-axis, said detector means being positioned at an angle α

from said x-axis.

12. A compact apparatus as recited in claim 11, wherein:

(a) said source means is positioned at first distance from said longitudinal axis of said sample chamber; and

(b) said detector means is positioned at a second distance from said longitudinal axis of said sample chamber.

13. A compact apparatus as recited in claim 12, wherein said first distance and said second distance are equal.

14. A compact apparatus as recited in claim 12, wherein said first distance and said second distance are not equal.

15. An apparatus for measurement of wear metal particles in a lubricant of a lubrication system of a machine, said apparatus comprising:

(a) a tubular sample chamber having an in-line connection with the lubrication system so that said sample chamber provides a passageway through which the lubrication flows, said sample chamber having an X-ray transparent window formed therein allowing passage of X-rays so that the presence of wear metal particles can be detected in the lubricant, said sample chamber having a longitudinal axis substantially parallel to the flow of the lubricant therethrough;

(b) a high intensity X-ray source assembly, said assembly directing said X-rays toward said sample chamber so that said X-rays pass through said window in said sample chamber and contact the lubricant, and metal particles that the lubricant may contain, flowing therethrough;

(c) an X-ray detector, said X-ray detector configured to detect said X-rays emitted by the lubricant, and by metal particles that may be contained therein, as the lubricant and metal particles flow through said sample chamber means, said detector means generating a signal representing a quantitative measure of said X-rays emitted by the lubricant and said X-rays emitted by the metal particles, and said X-ray detector having an X-ray transparent window formed therein and having a collimating/focusing assembly configured to deliver collimated/focused X-rays to said X-ray transparent window of said X-ray detector; and

(d) a signal processor, said signal processor being adapted to process said signal in order to determine the presence and amount of wear metal particles in the lubricant, thereby providing real-time identification and measurement of wear metal particles in the lubricant.

16. An apparatus as recited in claim 15, wherein said X-ray transparent window comprises material selected from the group consisting of beryllium, coated beryllium, polyimides, boron, and aluminum-coated polymers.

17. A apparatus as recited in claim 16, wherein said X-ray transparent material is beryllium.

18. An apparatus as recited in claim 15, wherein said sample chamber is substantially composed of a material selected from the group consisting of nylon, bakelite, or other plastic materials.

19. A apparatus as recited in claim 15, wherein said X-ray source assembly comprises:

(a) an X-ray tube configured to emit said X-rays; and

(b) a collimating/focusing assembly configured to focus said X-rays emitted from said X-ray tube as a high intensity, relatively small spot on said sample chamber.

20. A apparatus as recited in claim 19, wherein said X-ray collimating/focusing assembly comprises a plurality of hollow capillary tubes.

21. A apparatus as recited in claim 20, wherein said capillary tubes are substantially composed of glass.

22. A apparatus as recited in claim 20, wherein said capillary tubes have a diameter in the range of about 5 microns to about 50 microns.

23. A apparatus as recited in claim 19, wherein said X-ray collimating/focusing assembly comprises a block having a plurality of holes formed therein, said block being substantially composed of a low-density, light metal.

24. A apparatus as recited in claim 23, wherein said block is substantially composed of aluminum.

25. A apparatus as recited in claim 15, wherein said source assembly comprises an X-ray laser source capable of providing high intensity X-ray beams to said window in said sample chamber.

26. An apparatus as recited in claim 15, wherein said X-ray detector comprises a low-noise detector.

27. A apparatus as recited in claim 26, wherein said low-noise X-ray detector comprises a lithium drifted silicon detector.

28. An apparatus as recited in claim 15, further comprising a calibration device, the calibration device comprising a calibration sample configured to be movably disposed over said window in said sample chamber.

29. A apparatus as recited in claim 28, wherein said calibration sample comprises a copper disk.

30. An apparatus as recited in claim 15, wherein said source assembly and said detector are positioned on opposite sides of an x-axis formed through the center of said X-ray transparent window of said sample chamber, said x-axis being substantially perpendicular to said longitudinal axis of said sample chamber, said source assembly being positioned at an angle β

from said x-axis, said detector being positioned at an angle α

from said x-axis.

31. A apparatus as recited in claim 30, wherein said angle β

and said angle α

are not equal.

32. A apparatus as recited in claim 30, wherein said angle β

and said angle α

are equal.

33. A apparatus as recited in claim 15, wherein:

(a) said source assembly is laterally positioned at a first distance from said longitudinal axis of said sample chamber on the same side as said X-ray transparent window in said sample chamber; and

(b) said detector is laterally positioned at a second distance from said longitudinal axis of said sample chamber on the same side as said X-ray transparent window in said sample chamber.

34. A compact apparatus as recited in claim 33, wherein said first distance and said second distance are equal.

35. A apparatus as recited in claim 33, wherein said first distance and said second distance are not equal.

36. A miniaturized apparatus for measurement of wear metal particles in a lubricant of a lubrication system of a machine, said apparatus comprising:

(a) a non-metallic, cylindrical sample chamber having an in-line connection with the lubrication system of the machine so that said sample chamber provides a passageway through which the lubrication flows, said sample chamber having an X-ray transparent beryllium window formed therein allowing passage of X-rays so that the presence of wear metal particles can be detected in the lubricant, said sample chamber having a longitudinal axis substantially parallel to and concentric with the flow of the lubricant therethrough;

(b) a high intensity incident X-ray source assembly configured to provide a source of X-rays directed toward said sample chamber so that said X-rays pass through said window in said sample chamber and contact the lubricant, and metal particles that the lubricant may contain, flowing therethrough, said X-ray source assembly comprises;

(i) a monochromatic, single anode X-ray tube configured to emit X-rays, said X-ray tube having an X-ray transparent window formed therein;

(ii) a collimating/focusing assembly configured to collimate/focus said X-ray emitted from said X-ray tube as a high intensity, relatively small spot on said beryllium window in said sample chamber.

(c) an X-ray detector configured to detect said X-rays emitted by the lubricant, and by metal particles that may be contained therein, as the lubricant and metal particles flow through said sample chamber, said X-ray detector assembly generating a signal representing a quantitative measure of said X-rays emitted by the lubricant and said X-rays emitted by the metal particles, said X-ray detector assembly comprising;

(i) a low-noise lithium drifted silicon X-ray detector configured to detect said X-rays emitted by the lubricant, and by metal particles that may be contained therein, flowing through said sample chamber, said X-ray detector having an X-ray transparent window formed therein;

(ii) a collimating/focusing assembly capable of wide angle collection of the X-rays emitted by the lubricant, and by metal particles that may be contained therein, flowing through said sample chamber and to deliver collimated/focused X-rays to said window in said X-ray detector; and

(d) means for processing said signal in order to determine the presence and amount of wear metal particles in the lubricant, thereby providing real-time identification and measurement of wear metal particles in the lubricant.

37. A apparatus as recited in claim 36, wherein said X-ray tube comprises a pure-metal rhodium anode target.

38. A apparatus as recited in claim 36, wherein said beryllium window in said sample chamber is substantially circular.

39. A apparatus as recited in claim 36, wherein said sample chamber, said X-ray source assembly, and said X-ray detector assembly are miniaturized.

40. A apparatus as recited in claim 36, wherein said means for processing said signal from said X-ray detector to determine the presence and amount of wear metal particles in the lubricant comprises a computer system and associated software programs.

41. A method for using a compact apparatus for measurement of wear metal particles in a lubricant of a lubrication system of a machine, comprising the steps of:

(a) providing energy in the form of high intensity X-rays from an X-ray source assembly to a non-metallic sample chamber having an in-line connection to the lubrication system of the machine and through which the lubrication flows, said sample chamber having an X-ray transparent window formed therein allowing passage of X-rays so that said X-rays pass through said window in said sample chamber and contact the lubricant flowing therethrough to excite the lubricant at an atomic/molecular level;

(b) detecting said X-rays emitted from the lubricant flowing through said sample chamber using a low-noise X-ray detector assembly, said X-ray detector assembly generating a signal reflecting said X-rays emitted from the lubricant in the form of spontaneously emitted fluorescence X-rays;

(c) interpreting said signal received from said detector assembly to provide a real-time identification and measurement of the chemical composition of metal particles in the lubricant.

42. A method as recited in claim 41, further comprising the step of collimating/focusing said X-rays emitted by an X-ray tube using a collimating/focusing assembly thereby delivering a high-intensity, relatively small spot incident X-ray on said X-ray transparent window formed in said sample chamber prior to said detecting step.

43. A method as recited in claim 41, further comprising prior to said detecting step collimating or focusing said X-rays emitted from the lubricant using a collimating/focusing assembly in said X-ray detector assembly such that a collimated/focused high intensity X-ray reaches said X-ray detector assembly.