Method of visually inspecting turbine blades and optical inspection system therefor

• US 20060078193A1
• Filed: 10/08/2004
• Published: 04/13/2006
• Est. Priority Date: 10/08/2004
• Status: Active Grant

• Current Assignee: Siemens Energy Incorporated (Siemens AG)
• Original Assignee: Siemens Westinghouse Power Corporation
• Inventors: Twerdochlib, Michael, Lemieux, Dennis, Landi, William Alexander, Brummel, Hans-Gerd Johann, Masticola, Stephen Price
• Granted Patent: US 7,489,811 B2
• Time in Patent Office: Days
• US Class Current: 382/152
• CPC Class Codes: F05B 2230/80 Repairing, retrofitting or upgrading methods
• CPC Class Codes: F05B 2260/80 Diagnostics
• CPC Class Codes: G01N 21/8806 Specially adapted optical and illumination features
• CPC Class Codes: G01N 21/9515 Objects of complex shape, e.g. examined with use of a surface follower device measuring contours and curvatures G01B11/24
• CPC Class Codes: G01N 21/954 Inspecting the inner surface of hollow bodies, e.g. bores
• CPC Class Codes: G06T 7/0004 Industrial image inspection

Abstract

An optical inspection system is for visually inspecting the blades of a turbine at turning gear operation. The inspection system includes an imager for capturing images of the blades, an optical passage coupled to the imager and structured to provide maximum viewing area of the blades through an inspection port in the turbine and an illuminating assembly adapted to illuminate the blades while the imager captures images thereof. A method wherein the captured blade images are inspected for blade defects, is also disclosed.

Claims

1. An optical inspection system for visually inspecting a blade of a turbine, said turbine including an inspection port, said optical inspection system comprising:

an imager adapted to capture images of said blade while said turbine is at a turning gear operation;

a viewing device coupled to said imager and structured to permit said imager to view said blade through the inspection port of said turbine; and

an illuminating assembly adapted to illuminate said blade while said imager captures images thereof.

2. The optical inspection system of claim 1 further including a local monitoring computer;

wherein said imager is a computer-controlled camera; and

wherein said local monitoring computer is adapted to control said camera in order to automate the capturing of images of said blade and the inspection of said images for blade defects.

3. The optical inspection system of claim 1 wherein said viewing device includes a temperature-resistant window disposed between said imager and the inspection port of said turbine in order to permit viewing therethrough while shielding said imager.

4. The optical inspection system of claim 1 wherein said viewing device is an optical passage structured to maximize the amount of said blade which can be viewed through said inspection port, said optical passage including a first end, a second end and an intermediate portion therebetween;

wherein the first end of said optical passage is coupled to said inspection port; and

wherein said imager is coupled to the second end of said optical passage.

5. The optical inspection system of claim 4 wherein said optical passage further includes a high-speed shutter disposed proximate the second end thereof, adjacent said imager.

6. The optical inspection system of claim 4 further includes an image intensifier.

7. The optical inspection system of claim 4 wherein said illuminating assembly includes an illuminating device, a lens for concentrating light emitted from said illuminating device, and a deflector for directing the concentrated light onto said blade;

and wherein said illuminating assembly is coupled to the intermediate portion of said optical passage.

8. The optical inspection system of claim 7 wherein said illuminating device is selected from the group consisting of a flash and a continuous light source.

9. The optical inspection system of claim 7 wherein said deflector is a half-silvered mirror;

and wherein said half-silvered mirror is adjustable in order to deflect light emitted from said illuminating device onto said blade.

10. A method of visually inspecting a turbine during a turning gear operation comprising the steps of:

providing a turbine including a plurality of blades and an inspection port for viewing said plurality of blades, said blades being coupled to a rotating shaft;

providing an optical inspection system for visually inspecting at least one of said plurality blades through said inspection port, said optical inspection system including an imager, a viewing device coupled to said imager and adapted to capture images of said at least one of said plurality of said blades through said inspection port, and an illuminating assembly adapted to illuminate said at least one of said plurality of blades while said imager captures images thereof;

determining when said turbine is in said turning gear operation;

monitoring the position of the shaft of said turbine in order to determine when said at least one of said plurality of blades is in proper view for capturing images;

illuminating said at least one of said plurality of blade;

capturing images of said at least one of said plurality;

deconvolving the images; and

analyzing the images in order to determine whether or not any of said plurality of blades has a defect.

11. The method of claim 10 wherein said optical inspection system includes a local monitoring computer;

and wherein said local monitoring computer automates one or more of the steps of said method of visually inspecting a turbine during a turning gear operation.

12. The method of claim 11 wherein said step of analyzing the images for blade defects includes fusing previously acquired images of a blade with the most recently acquired image of the same blade.

13. The method of claim 11 wherein said step of analyzing the images for blade defects includes fusing turbine sensor data and turbine monitoring system output.

14. The method of claim 11 wherein said step of analyzing the images for blade defects includes alarming other monitoring systems when a defect is detected.

15. The method of claim 11 wherein said step of analyzing the images for blade defects includes selecting certain captured images for storage in a local storage bank.

16. The method of claim 15 including sending selected stored images to other monitoring and control systems.

17. The method of claim 15 including deleting selected images from said local storage bank when the images are no longer useful.

18. The method of claim 11 wherein said imager includes a bandpass filter;

and wherein said step of analyzing the images for blade defects includes the steps of changing the bandpass filter and capturing images with the different bandpass filter.

19. The method of claim 11 wherein said step of analyzing the images for blade defects includes subtracting images taken at different times or with different bandpass filters in order to detect changes in said blades.

20. The method of claim 11 wherein said step of illuminating the blades further includes the step of controlling functions of the illuminating assembly.

21. The method of claim 11 wherein said step of capturing the images further includes the step of controlling functions of the imager.