Method for the Detection of Errors in Pump Units

• US 20100082275A1
• Filed: 02/23/2008
• Published: 04/01/2010
• Est. Priority Date: 03/23/2007
• Status: Active Grant

• Current Assignee: Grundfos Management A/S (POUL DUE Jensen's FOND)
• Original Assignee: Grundfos Management A/S (POUL DUE Jensen's FOND)
• Inventors: Munk, Flemming, Borsting, Hakon
• Granted Patent: US 8,401,806 B2
• Time in Patent Office: Days
• US Class Current: 702/56
• CPC Class Codes: F04D 15/0066 by changing the speed, e.g. of the driving engine
• CPC Class Codes: F04D 15/0088 Testing machines
• CPC Class Codes: F04D 29/669 especially adapted for liquid pumps F04D29/18 takes precedence
• CPC Class Codes: F05D 2270/709 with neural networks

Abstract

A method is provided for detecting faults in a pump assembly having an electric motor, or faults in an electric motor, having at least one rotating shaft. A vibration signal is detected, the detected vibration signal is processed in a manner such that the influence of the current rotational speed of the shaft is eliminated, periodic signals are filtered out of the processed vibration signal, and the vibrational operating condition, in particular possible faults, is recognized by way of the periodic signals. Further, a pump assembly having an electric motor or an electric motor is provided in which this method is applied.

Claims

1-14. -14. (canceled)

15. A method for detecting faults in a pump assembly having an electric motor or faults in an electric motor, wherein the pump assembly or electric motor has at least one rotating shaft, the method comprising:

detecting a vibration signal in the pump or electric motor,

processing the detected vibration signal in a manner such that influence of a current rotational speed of the shaft is eliminated,

filtering out periodic signals of the processed vibration signal, and

recognizing a vibrational operating condition including any possible faults by way of the periodic signals.

16. The method according to claim 15, wherein the processed vibration signal is subjected to a Cepstral analysis and the vibrational operating condition is recognized by way of a Cepstral diagram produced by the Cepstral analysis.

17. The method according to claim 16, wherein a pattern recognition is carried out for recognizing the vibrational operating condition from the Cepstral diagram, wherein the pattern recognition particularly takes into account at which locations swings occur in the Cepstral diagram.

18. The method according to claim 16, wherein the vibrational operating condition is recognized by way of previously known patterns in the Cepstral diagram.

19. The method according to claim 16, wherein the recognition of the vibrational operating condition is effected in selected sections of the Cepstral diagram, particularly predefined sections.

20. The method according to claim 16, wherein the recognition of the vibrational operating condition is effected by way of the Cepstral diagram and by way of a neural network and/or fuzzy logic.

21. The method according to claim 16, wherein after the Cepstral analysis and before the recognition of the vibrational operating condition, a step of normalizing the Cepstral diagram takes place in a manner such that swings in the diagram are set in relation to background noises.

22. A pump assembly having an electric motor (23) or an electric motor (23), wherein the pump assembly or the electric motor has at least one rotating shaft and a fault detection system, the fault detection system comprising at least one vibration sensor (20, 22), an evaluation device connected to the vibration sensor (20, 22), wherein the evaluation device is provided with a processing module (2) designed for eliminating influence of a current rotational speed of the shaft from a vibration signal captured by the vibration sensor (20, 22), a filter module (4) designed for filtering periodic signals out of the vibration signal processed by the processing module, and a recognition module (7) designed for recognizing a vibrational operating condition by way of the periodic signals.

23. The pump assembly or electric motor according to claim 22, wherein the filter module comprises a Cepstral analysis module (4) is designed for carrying out a Cepstral analysis on the vibration signal processed by the processing module (2), and the recognition module (7) is designed for recognition of the vibrational operating condition by way of a Cepstral diagram produced by the Cepstral analysis module.

24. The pump assembly or electric motor according to claim 22, wherein the recognition module (7) comprises a fuzzy logic and/or a neural network.

25. The pump assembly or electric motor according to claim 23, wherein the evaluation device comprises a memory module in which characteristic patterns of a Cepstral diagram are stored for certain operating conditions, and the recognition module (7) is designed for recognizing the vibrational operating condition on the Cepstral diagram by way of the stored patterns.

26. The pump assembly or electric motor according to claim 22, wherein the vibration sensor (20, 22) is arranged on a mechanical structure (26) of the pump assembly or of the electric motor (23), in a terminal box (24), within an arrangement of electronic components and/or in a fluid conduit for a fluid to be delivered by the pump assembly.

27. The pump assembly or electric motor according to claim 22, further comprising a wireless signal transmission device for transmitting signals between the vibration sensor (20, 22) and the evaluation device.

28. The pump assembly or electric motor according to claim 23, wherein the evaluation device comprises a normalization module (6) designed for normalizing the Cepstral diagram produced by the Cepstral analysis module (4) in such a manner that swings in the Cepstral diagram are set in relation to background noises.