Vibration analysis for predictive maintenance in machinery

• US 20040199348A1
• Filed: 05/24/2004
• Published: 10/07/2004
• Est. Priority Date: 07/09/2001
• Status: Active Grant

• Current Assignee: Shell Oil Company (Shell Plc)
• Original Assignee: Shell Oil Company (Shell Plc)
• Inventors: Hitchcock, Leith Patrick, Schmitz, Nicholas
• Granted Patent: US 7,099,782 B2
• Time in Patent Office: Days
• US Class Current: 702/92
• CPC Class Codes: G01H 1/003 of rotating machines G01H1/10 takes precedence
• CPC Class Codes: G01M 13/028 Acoustic or vibration analysis

Abstract

A method for detecting vibration signatures in a reversible drive is disclosed. The method includes the steps of acquiring digital data representative of vibrations in the reversible drive and identifying and grouping together portions of data in a plurality of groups. The identified portions of data relate to a particular direction of travel of the reversible drive and the plurality of groups relate to travel in different directions of the reversible drive. The method can include the further step of processing at least one of the groups of data using signal processing techniques. A system and computer program product for practicing the method for detecting vibration signatures in a reversible drive are also disclosed.

Claims

1. A method for detecting vibration signatures in a reversible drive, said method comprising the steps of:

acquiring digital data representative of vibrations in said reversible drive;

identifying portions of said data using a processor means; and

grouping together said identified portions of data in a plurality of groups;

wherein each of said identified portions of data relate to a particular direction of travel of said reversible drive and said plurality of groups relate to different directions of travel of said reversible drive.

2. The method of claim 1, wherein grouping together identified portions of data relating to a particular direction of travel is done by appending successive portions to an accumulation of previous data portions also relating to the particular direction..

3. The method of claim 1 wherein each successive sample of each of said one or more groups of identified portions of data corresponds to a successive sample position of said reversible drive.

4. The method of claims 1, wherein the reversible drive changes its direction of travel while the data is acquired.

5. The method of claim 1, wherein said identified portions of data are representative of substantially constant speed of operation of said reversible drive.

6. The method of claim 1, wherein said digital data includes data sampled at a variable sampling rate synchronized to the speed of said reversible drive.

7. The method of claim 1, wherein said digital data includes data sampled at a fixed time interval sampling rate.

8. The method of claim 7, further comprising the step of resampling said digital data, wherein each successive sample of the resampled digital data corresponds to a successive position of said reversible drive and the distance between each of said successive positions is a constant amount.

9. The method of claim 1, further comprising the step of processing at least one of said groups of identified portions of data to produce data representative of one or more vibration signatures.

10. The method of claim 9, wherein said processing step comprises one or more steps selected from the group consisting of:

accumulating the average, in the time domain, of the data comprising one of said groups;

accumulating the average, in the angle domain, of the data comprising one of said groups;

accumulating the average, in the frequency domain, of the data comprising one of said groups;

accumulating the average, in the orders domain, of the data comprising one of said groups;

computing a time synchronised average time waveform of the data comprising one of said groups;

computing a frequency spectrum of a time synchronised average of the data comprising one of said groups;

computing an order tracked frequency spectrum of the data comprising one of said groups;

computing the kurtosis of an accumulated time domain average;

computing the kurtosis of an accumulated angle domain average;

computing the kurtosis of a time synchronized average time waveform; and

computing a demodulated frequency spectrum of the data comprising one of said groups.

16. The method of claim 2 wherein each successive sample of each of said one or more groups of identified portions of data corresponds to a successive sample position of said reversible drive.

17. The method of claim 2 wherein the reversible drive changes its direction of travel while the data is acquired.

18. The method of claim 3 wherein the reversible drive changes its direction of travel while the data is acquired.

19. The method of claim 1 wherein the identified portions of data in the forward and reverse directions of travel are separated.

11. A system for detecting vibration signatures in a reversible drive, comprising:

transducer means for acquiring digital data representative of vibrations in said reversible drive;

processor means for identifying portions of said data; and

processor means for grouping together said identified portions of data in a plurality of groups;

wherein each of said identified portions of data relate to a particular direction of travel of said reversible drive and said plurality of groups relate to different directions of travel of said reversible drive.

12. A computer program product having a computer readable medium having a computer program recorded therein for detecting vibration signatures in a reversible drive, wherein said computer program product comprises:

computer program code means for acquiring digital data representative of vibrations in said reversible drive;

computer program code means for identifying portions of said data; and

computer program code means for grouping together said identified portions of data in a plurality of groups;

wherein each of said identified portions of data relate to a particular direction of travel of said reversible drive and said plurality of groups relate to different directions of travel of said reversible drive.

13. A method for detecting vibration signatures in a rotating and/or cyclic machinery, comprising the steps of:

acquiring digital data representative of vibrations in the machinery, wherein the data includes data acquired at different speeds of the machinery;

identifying portions of the data relating to a predetermined speed and acceleration range of the machinery and for identifying portions of the data outside the predetermined speed and acceleration range, wherein a processor means is used for identifying the portions of the data; and

grouping together the identified portions of data relating to the predetermined speed and acceleration range in a group relating to data in the predetermined speed and acceleration range, by appending successive portions to an accumulation of previous data portions also relating to the predetermined speed and acceleration range.

14. A system for detecting vibration signatures in a rotating and/or cyclic machinery comprising:

transducer means for acquiring digital data representative of vibrations in the machinery;

processor means for identifying portions of said data relating to a predetermined speed and acceleration range of the machinery and for identifying portions of the data outside the predetermined speed and acceleration range; and

processor means for grouping together said identified portions of data relating to the predetermined speed and acceleration range in a group relating to data in the predetermined speed and acceleration range by appending successive portions to an accumulation of previous data portions also relating to the predetermined speed and acceleration range.

15. A computer program product having a computer readable medium having a computer program recorded therein for detecting vibration signatures in a rotating and/or cyclic machinery said computer program product comprising:

computer program code means for acquiring digital data representative of vibrations in the machinery;

computer program code means for identifying portions of said data relating to a predetermined speed and acceleration range of the machinery and for identifying portions of the data outside the predetermined speed and acceleration range; and

computer program code means for grouping together said identified portions of data relating to the predetermined speed and acceleration range in a group relating to data in the predetermined speed and acceleration range by appending successive portions to an accumulation of previous data portions also relating to the predetermined speed and acceleration range.