METHOD AND SYSTEM FOR PREDICTING ERRORS ON COMPONENTS OF ROTATING MACHINES BY THERMOGRAPHY

• US 20130169799A1
• Filed: 07/12/2011
• Published: 07/04/2013
• Est. Priority Date: 07/13/2010
• Status: Active Grant

• Current Assignee: PRÜFTECHNIK Dieter Busch GmbH
• Original Assignee: PRÜFTECHNIK Dieter Busch AG (Fortive Corp.)
• Inventors: Hoelzl, Roland
• Granted Patent: US 9,240,040 B2
• Time in Patent Office: Days
• US Class Current: 348/135
• CPC Class Codes: G01N 25/00 Investigating or analyzing materials by the use of thermal means G01N3/00 - G01N23/00 take precedence
• CPC Class Codes: G01N 25/72 Investigating presence of flaws
• CPC Class Codes: G06F 16/51 Indexing; Data structures therefor; Storage structures
• CPC Class Codes: G06F 18/22 Matching criteria, e.g. proximity measures
• CPC Class Codes: G06T 2207/10048 Infrared image
• CPC Class Codes: G06T 2207/30164 Workpiece; Machine component
• CPC Class Codes: G06T 7/0004 Industrial image inspection
• CPC Class Codes: G06T 7/001 using an image reference approach
• CPC Class Codes: H04N 23/63 by using electronic viewfinders
• CPC Class Codes: H04N 5/265 Mixing
• CPC Class Codes: H04N 5/33 Transforming infrared radiation cameras or camera modules for generating image signals from infrared radiation H04N23/20; circuitry of SSIS for transforming infrared radiation into image signals H04N25/20

Abstract

Computer-based detection of damage on machine components, such as misalignments and mechanical damage on bearings and clutches, is achieved using mathematical linkage of the temperatures of selected regions of thermography pictures. Photographs from the visible spectral range can be consulted in the computed-based detection.

Claims

1-17. -17. (canceled)

18. A method for determining the state of components of a machine by evaluation of thermography pictures, comprising the steps of:

comparing at least one first thermography picture to at least one reference thermography picture obtained previously,

assigning at least one first pixel group of pixels in the at least one first thermography picture and in the at least one reference thermography picture as at least one cold site,

wherein normalization of the at least one first thermography picture is performed with the result of a mathematical linkage of the temperatures of the at least one cold site in the at least one first thermography picture and in the at least one reference thermography picture, and

wherein after said normalization, at least one second pixel or group of pixels is identified in the at least one first thermography picture as at least one first hot site and compared to the at least one reference thermography picture and assigned to a certain machine component.

19. The method as claimed in claim 18, comprising the further step of drawing a conclusion about the state of the machine component which has been assigned to the first hot site.

20. The method as claimed in claim 18, wherein in the at least one first thermography picture and the at least one reference thermography picture, at least one second hot site is assigned to at least a respective third pixel or group of pixels whose temperature enables a conclusion about an operating parameter of the machine, and wherein the temperature of at least one second hot site is included in the mathematical linkage of the temperatures of the at least one cold site in the first thermography picture and the at least one reference picture.

21. The method as claimed in claim 18, wherein ambient temperature is included in the mathematical linkage of the temperatures of the at least one cold site in the first thermography picture and the at least one reference thermography picture.

22. The method as claimed in claim 18, wherein operating parameters of the machine are included in the mathematical linkage.

23. The method as claimed in claim 18, wherein the first thermography picture and the at least one reference thermography picture are superimposed before assignment of the pixel or groups of pixels to one of the cold and hot sites such that cold and hot sites coincide on the superimposed pictures.

24. The method as claimed in claim 23, wherein a picture from the visible spectral range is additionally superimposed in the superposition of the at least one first thermography picture and the at least one reference thermography picture.

25. The method as claimed in claim 23, wherein a sighting mark is considered in the superposition of the at least one first thermography picture and the at least one reference thermography picture.

26. The method as claimed in claim 25, wherein the sighting mark is produced with a laser beam.

27. The method as claimed in claim 25, wherein the sighting mark is produced by a reticle.

28. The method as claimed in claim 18, wherein at least one of a clutch which connects two shafts to one another and a rolling bearing is used as the machine component.

29. The method as claimed in claim 18, wherein a database stores reference values for at least one of cold and hot sites, operating parameters, ambient temperatures and state variables of the respective machine components and emissivities of the surfaces of the respective machine components.

30. The method as claimed in claim 29, wherein the database stores previously obtained thermography pictures and pictures from the visible spectral range.

31. The method as claimed in claim 30, wherein results of the mathematical linkage and the pictures which have been stored in the database are superimposed and the result of the superposition is displayed to a user as a result picture.

32. A system for determining the state of components of a machine by evaluation of thermography pictures, comprising:

a thermography camera for taking thermography pictures,

a computer system,

a database in which reference pictures taken by the thermography camera are stored,

software implemented on the computer system for carrying out normalization a temperature at one cold site and at least one hot site by a mathematical linkage comparison of at least one first thermography picture with a reference picture from the database, the result of the mathematical linkage of the temperatures, and

a display for displaying the result of the mathematical linkage.

33. The system as claimed in claim 32, further comprising a camera for taking visible spectral range images.

34. The system as claimed in claim 32, wherein the result of the mathematical linkage is displayed as at least one of a superposition of several thermography pictures and a superposition with a picture from the visible spectral range.