Method and apparatus for predictive diagnosis of moving machine parts

• US 5,852,793 A
• Filed: 02/18/1997
• Issued: 12/22/1998
• Est. Priority Date: 02/18/1997
• Status: Expired due to Term

• Current Assignee: Astronics DME LLC (Astronics Corporation)
• Original Assignee: DME Company LLC (Milacron Holdings Corp.)
• Inventors: Cates, Harold, Rawlings, Eric, Board, David B.
• Primary Examiner(s): Trammell, James P.
• Assistant Examiner(s): Smithers, Matthew
• Application Number:
  US08/800,812
• Time in Patent Office: 672 Days
• Field of Search: 364/550, 364/551.01, 73/488, 73/577, 73/584, 73/593, 702/56, 702/183
• US Class Current: 702/56
• CPC Class Codes: F16C 19/527 related to vibration and noise
• CPC Class Codes: G01H 1/003 of rotating machines G01H1/10 takes precedence
• CPC Class Codes: G01M 13/028 Acoustic or vibration analysis
• CPC Class Codes: G01M 13/045 Acoustic or vibration analysis

Abstract

For automatically predicting machine failure a transducer sensor, such as piezoelectric crystal, is applied to a machine for sensing machine motion and structure-borne sound, including vibration friction, and shock waves. The structure-borne sound and motion sensed is converted to electrical signals which are filtered to leave only the friction and shock waves, which waves are processed, as by detecting the envelope and integrating beneath the envelope, resulting in a measure of friction and shock wave energy, i.e., stress wave energy. This measure is computed and processed for producing fault progression displays for periodic and aperiodic damage. This is accomplished in a personal computer, menu-driven environment.

Claims

1. A system for predicting failures in rotary and reciprocating machinery including bearings, gears, lubricants, and the like by communicating with a plurality of vibration, shock and friction sensing transducers attached to the machinery, said system comprising:

a signal receiving means for electrically communicating with the plurality of transducers to receive a corresponding number of electrical signals produced by the sensors and corresponding to vibration, friction, and shock waves produced in the machinery during operation;

an analog signal conditioner, in electrical communication with said signal receiving means, comprising means for filtering out signal components from the signals corresponding to vibration and passing only components of the signals corresponding to friction and shock waves and means for detecting envelopes of the signals in said frequency band;

digital processor means, in electrical communication with said analog signal conditioner, for converting analog signals to digital, for computing stress wave energy corresponding to said envelopes and for providing control and display logic to select transducing sensors to be monitored; and

control and display means, in electrical communication with said digital processor means, for dictating which transducers to monitor via said control and display logic and for dictating information to be displayed.

2. A system as recited in claim 1, wherein said filtering means includes a band pass filter.

3. A system as recited in claim 1, wherein said sensors comprise non-linear stress wave sensors that resonate above 10 khz.

4. A system as recited in claim 1, wherein said control and display means comprises:

a control processor means for reading and processing a medium of instruction code and a display means for displaying control processor selected information, said control processor means being in electrical communication with said digital processor means, and said display means, for selecting the signals to be processed by said digital processor means, for processing said stress wave energy computation and for controlling the display of said stress wave energy computation, respectively.

5. A system as recited in claim 4, wherein said signal receiving means comprises:

a multiplexer, in electrical communication with the transducers and said analog signal conditioner, for receiving the electrical signals from the transducers and transmitting at least one preselected signal, each said preselected signal being determined by said processor means.

6. A system as recited in claim 4, wherein said analog signal conditioner comprises:

a filtering means, in electrical communication with said multiplexer, for filtering frequencies in each said preselected signal corresponding to the friction and shock waves to arrive at a resultant signal for each said signal, said resultant signal being in a predetermined frequency range corresponding to said transducers.

7. A system as recited in claim 6, wherein said envelope detecting means comprises:

a demodulator means, in electrical communication with said digital processor means, for detecting envelopes in each said preselected signal and for producing a stress wave pulse train, said stress wave pulse trains being processed by said digital processor means for computing the stress wave energy.

8. A system as recited in claim 7, wherein said digital processor means comprises:

an integrator means, in electrical communication with said control processor means, for integrating said stress wave pulse trains to arrive at said stress wave energy computation.

9. A system as recited in claim 8, wherein said digital processor further means comprises:

a peak detection means, in electrical communication with said control processor means, for measuring peak amplitude levels of said stress wave pulse trains.

10. A system as recited in claim 4, wherein said medium of instruction code comprises:

means for selecting said transducers for digital processing by said digital processor means.

11. A system as recited in claim 10 wherein said sensor selecting means further comprises:

a scanning means for selectively scanning through said transducers to be selected for digital processing by said digital processor means.

12. A system as recited in claim 10, wherein said medium of instruction code comprises:

means for computing stress wave energy measurements in said signals generated by said transducers.

13. A system for predicting failures in rotary and reciprocating machinery including bearings, gears, lubricants, and the like by communicating with a plurality of vibration, shock and friction sensing transducers attached to the machinery, said system comprising:

a signal receiving means for electrically communicating with the plurality of transducers to receive a corresponding number of electrical signals produced by the sensors and corresponding to vibration, friction, and shock waves produced in the machinery during operation;

an analog signal conditioner, in electrical communication with said signal receiving means, comprising means for filtering out signal components from the signals corresponding to vibration and passing only components of the signals corresponding to friction and shock waves and means for detecting envelopes of the signals in said frequency band;

digital processor means, in electrical communication with said analog signal conditioner, for converting analog signals to digital, for computing stress wave energy corresponding to said envelopes and for providing control and display logic to select transducing sensors to be monitored;

control and display means, in electrical communication with said digital processor means, for dictating which transducers to monitor via said control and display logic and for dictating information to be displayed; and

means for creating a histogram of said stress wave energy measurements over a selected period of time.

14. A system for predicting failures in rotary and reciprocating machinery, including bearings, gears, lubricants, and the like, said system comprising:

a plurality of stress wave sensor transducers for attachment to the machinery at selected points to produce a corresponding number of electrical signals corresponding to vibration, friction, and shock waves produced in the machinery during operation;

multiplexing means, in electrical communication with said transducers, for receiving said electrical signals from said transducers and transmitting at least one selected signal corresponding to at least one preselected transducer;

filtering means, in electrical communication with said multiplexing means, for filtering out frequencies corresponding to vibration and passing only friction and shock waves, said filtering means deriving a resultant signal for each said preselected signal, said resultant signal being in a predetermined frequency range corresponding to said transducers;

digital processor means, in electrical communication with said filtering means, for converting analog signals to digital, for computing stress wave energy corresponding to said envelopes and for providing control and display logic to select transducers to be monitored; and

control processing means, in electrical communication with said multiplexing means and said digital processing means for selecting said at least one selected signal, for communicating with said transducers and for displaying friction and shock wave energy measurements and envelope measurements.

15. A system as recited in claim 14, wherein said filtering means includes a band pass filter.

16. A system as recited in claim 14, wherein said sensors comprise non-linear stress wave sensors that resonate above 10 khz.

17. A system as recited in claim 14, wherein said control processing means comprises:

code means for reading and processing a medium of instruction code and a display means for displaying control processor selected information, said code means being in electrical communication with said display means, said control processing means processing said code means for selecting said signals to be processed by said digital processor means, for processing said stress wave energy computation and for controlling the display of said stress wave energy computation, respectively.

18. A system as recited in claim 17, further comprising:

a demodulator means, in electrical communication with said filtering means and said digital processor means, for producing a stress wave pulse train, said stress wave pulse trains being processed by said digital processor means for computing the stress wave energy.

19. A system as recited in claim 18, wherein said digital processor means comprises:

an integrator means, in electrical communication with said control processor means, for integrating said stress wave pulse trains to arrive at said stress wave energy computation.

20. A system as recited in claim 19, wherein said digital processor means further comprises:

a peak detection means, in electrical communication with said control processing means, for measuring peak amplitude levels of said stress wave pulse trains.

21. A system as recited in claim 20, wherein said plurality of transducers comprise piezoelectric crystal transducer sensors.

22. A system as recited in claim 17, wherein said medium of instruction code comprises:

means for selecting said transducers for digital processing by said digital processor means.

23. A system as recited in claim 22, wherein said transducer selecting means further comprises:

a scanning means for selectively scanning through said transducers to be selected for digital processing by said digital processor means.

24. A system as recited in claim 23, wherein said medium of instruction code comprises:

means for computing stress wave energy measurements in said signals generated by said transducers.

25. A system for predicting failures in rotary and reciprocating machinery, including bearings, gears, lubricants, and the like, said system comprising:

a plurality of stress wave sensor transducers for attachment to the machinery at selected points to produce a corresponding number of electrical signals corresponding to vibration, friction, and shock waves produced in the machinery during operation;

multiplexing means, in electrical communication with said transducers, for receiving said electrical signals from said transducers and transmitting at least one selected signal corresponding to at least one preselected transducer;

filtering means, in electrical communication with said multiplexing means, for filtering out frequencies corresponding to vibration and passing only friction and shock waves, said filtering means deriving a resultant signal for each said preselected signal, said resultant signal being in a predetermined frequency range corresponding to said transducers;

digital processor means, in electrical communication with said filtering means, for converting analog signals to digital, for computing stress wave energy corresponding to said envelopes and for providing control and display logic to select transducers to be monitored;

control processing means, in electrical communication with said multiplexing means and said digital processing means for selecting said at least one selected signal, for communicating with said transducers and for displaying friction and shock wave energy measurements and envelope measurements; and

means for creating a histogram of said stress wave energy measurements over a selected period of time.

26. A system for predicting failures in rotary and reciprocating machinery by receiving and processing electrical signals produced by a plurality of motion sensing transducers and indicative of vibration, friction and shock waves, said signals corresponding to vibration, friction, and shock waves produced in the machinery during operation, said machinery, including bearings, gears, lubricants, and the like, said system comprising:

multiplexing means, in electrical communication with said transducers, for receiving said electrical signals from said transducers and transmitting at least one selected signal corresponding to at least one preselected transducer;

filtering means, in electrical communication with said multiplexing means, for filtering out frequencies corresponding to vibration and passing only frequencies corresponding to friction and shock waves, said filtering means deriving a resultant signal for each said preselected signal, said resultant signal being in a predetermined frequency range corresponding to said transducers;

digital processor means, in electrical communication with said filtering means, for converting analog signals to digital, for computing stress wave energy corresponding to said envelopes and for providing control and display logic to select transducers to be monitored; and

control processing means, in electrical communication with said multiplexing means and said digital processing means for selecting said at least one selected signal, for communicating with said transducers and for displaying friction and shock wave energy measurements and envelope measurements.

27. A system as recited in claim 26, wherein said filtering means includes a band pass filter.

28. A system as recited in claim 26, wherein said sensors comprise non-linear stress wave sensors that resonate above 10 khz.

29. A system as recited in claim 26, wherein said control processing means comprises:

code means for reading and processing a medium of instruction code and a display means for displaying control processor selected information, said code means being in electrical communication with said display means, said control processing means processing said code means for selecting said signals to be processed by said digital processor means, for processing said stress wave energy computation and for controlling the display of said stress wave energy computation, respectively.

30. A system as recited in claim 29, further comprising:

a demodulator means, in electrical communication with said filtering means and said digital processor means, for producing a stress wave pulse train, said stress wave pulse trains being processed by said digital processor means for computing the stress wave energy.

31. A system as recited in claim 30, wherein said digital processor means comprises:

an integrator means, in electrical communication with said control processor means, for integrating said stress wave pulse trains to arrive at said stress wave energy computation.

32. A system as recited in claim 31, wherein said digital processor further means comprises:

a peak detection means, in electrical communication with said control processing means, for measuring peak amplitude levels of said stress wave pulse trains.

33. A system as recited in claim 32, wherein said medium of instruction code comprises:

means for selecting said transducers for digital processing by said digital processor means.

34. A system as recited in claim 33, wherein said sensor selecting means further comprises:

a scanning means for selectively scanning through said transducers to be selected for digital processing by said digital processor means.

35. A system as recited in claim 34, wherein said medium of instruction code comprises:

means for computing stress wave energy measurements in said signals generated by said transducers.

36. A system for predicting failures in rotary and reciprocating machinery by receiving and processing electrical signals produced by a plurality of motion sensing transducers and indicative of vibration, friction and shock waves, said signals corresponding to vibration, friction, and shock waves produced in the machinery during operation, said machinery, including bearings, gears, lubricants, and the like, said system comprising:

multiplexing means, in electrical communication with said transducers, for receiving said electrical signals from said transducers and transmitting at least one selected signal corresponding to at least one preselected transducer;

filtering means, in electrical communication with said multiplexing means, for filtering out frequencies corresponding to vibration and passing only frequencies corresponding to friction and shock waves, said filtering means deriving a resultant signal for each said preselected signal, said resultant signal being in a predetermined frequency range corresponding to said transducers;

digital processor means, in electrical communication with said filtering means, for converting analog signals to digital, for computing stress wave energy corresponding to said envelopes and for providing control and display logic to select transducers to be monitored;

control processing means, in electrical communication with said multiplexing means and said digital processing means for selecting said at least one selected signal, for communicating with said transducers and for displaying friction and shock wave energy measurements and envelope measurements; and

means for creating a histogram of said stress wave energy measurements over a selected period of time.