Gap inspection apparatus

• US 8,220,345 B2
• Filed: 04/13/2009
• Issued: 07/17/2012
• Est. Priority Date: 04/14/2008
• Status: Active Grant

• Current Assignee: General Electric Technology GmbH (GE Aerospace)
• Original Assignee: Alstom Technology Ltd. (Alstom SA)
• Inventors: Hugi, Niklaus, Mark, Bernhard, Isler, Philipp, Honold, Simon, Erni, Josef, Moser, Roland
• Primary Examiner(s): Williams, Hezron E
• Assistant Examiner(s): Redmann, Gregory J
• Application Number:
  US12/422,341
• Publication Number:
  US 20090256584A1
• Time in Patent Office: 1,191 Days
• Field of Search: 738/665
• US Class Current: 73/866.5
• CPC Class Codes: G01R 31/34 Testing dynamo-electric machines
• CPC Class Codes: H02K 11/20 for measuring, monitoring, testing, protecting or switching rectifiers H02K11/04; power electronics H02K11/33

Abstract

An apparatus for inspection of a gap between two surfaces, at least one of which is ferromagnetic, for example in a generator, includes a sensor platform (26) for one or more sensors (26a) and an elongated mount (23), which can be moved out, for the sensor platform (26). The mount (23) can be moved in and out of the gap through an access opening, can be moved out over the length of the gap and can be rolled up outside the gap by a drive (24). In its moved-out state, the mount (23) has a curvature in a lateral cross section. In addition, the mount (23) has a plurality of magnets (27) by which the mount (23) is brought into contact with a ferromagnetic surface. The magnets (27) are attached to the side of the mount (23) facing away from the ferromagnetic surface, ensuring that the mount (23) slides along a ferromagnetic surface. The apparatus allows inspection of gaps from a height of 4 mm and is distinguished by a simple and physically small design.

Claims

1. An apparatus for inspection of a gap between two surfaces, at least one surface of which is ferromagnetic, comprising:

a sensor platform with at least one sensor;

an elongated, movable, and rollable mount, the sensor platform being attached to the mount, wherein the mount is movable into and out of the gap through an access opening and over the length of the gap;

a plurality of magnets arranged on the mount, which magnets are distributed over the length of the mount and bring the mount into contact with said ferromagnetic surface when the mount is inserted into the gap, and wherein the magnets are attached to a surface of the mount facing away from the ferromagnetic surface; and

a roller, wherein the mount is supported by and at least partially rolled up on the roller.

2. The apparatus for inspection of a gap as claimed in claim 1, wherein the mount has a curved lateral cross-sectional shape.

3. The apparatus for inspection of a gap as claimed in claim 1, wherein the sensor platform comprises at least one magnet and at least one rolling or sliding element, and wherein the height of the at least one rolling or sliding element is greater than the height of the at least one magnet.

4. The apparatus for inspection of a gap as claimed in claim 1, further comprising:

a mounting or storage roller with a flat rolling surface onto which the mount can be rolled with a flat cross section and from which the mount can be rolled off; and

at least one pair of guide elements, wherein each pair of guide elements comprises an element with convex surfaces and an element with concave surfaces with the same curvature as said convex surfaces, and wherein the convex element is positioned relative to the concave element such that a convex-curved part of the convex element projects into a concave-curved part of the concave element, and the mount can be moved between the two guide elements.

5. The apparatus for inspection of a gap as claimed in claim 1, wherein the mount includes longitudinal sides, wherein the mount comprises a plurality of openings along said longitudinal sides which are separated from one another by a regular distance, and further comprising:

a transport roller with a plurality of studs configured and arranged to engage the openings on the mount.

6. The apparatus for inspection of a gap as claimed in claim 1, further comprising:

cables arranged along the mount configured and arranged to transmit measurement signals from the one or more sensors on the sensor platform to an opposite end of the mount.

7. The apparatus for inspection of a gap as claimed in claim 1, wherein the sensor platform comprises electronics configured and arranged to digitize the measurement signals and to transmit the measurement signals in accordance with a transmission protocol.

8. The apparatus for inspection of a gap as claimed in claim 7, further comprising:

a storage roller for the mount to roll on; and

a slipring on said storage roller configured and arranged to transmit the measurement signals from said opposite end of the mount to a signal processing apparatus.

9. The apparatus for inspection of a gap as claimed in claim 1, wherein the mount comprises at least one elongated strip formed of a flexibly elastic metal which, in a rolled-out state, has a curvature with a convex side and a concave side in lateral cross section.

10. The apparatus for inspection of a gap as claimed in claim 9, wherein, in the rolled-out state, the mount is subject to a rolling-in stress and is subject to a lateral bending stress, wherein the lateral bending stress is greater than the rolling-in stress.

11. The apparatus for inspection of a gap as claimed in claim 1, wherein, on the convex side, the mount has a strip or polymer coating which can slide on metal.

12. The apparatus for inspection of a gap as claimed in claim 11, wherein said polymer comprises polytetrafluoroethylene or polyethylene.

13. The apparatus for inspection of gap as claimed in claim 1, further comprising:

a motor configured and arranged to roll up the mount outside of the gap.

14. The apparatus for inspection of a gap as claimed in claim 13, further comprising:

a second drive configured and arranged to move the apparatus over the circumference of a rotor of a generator, the second drive being radially movable.

15. The apparatus for inspection of a gap as claimed in claim 1, wherein the sensor platform comprises at least one sensor configured and arranged for visual inspection or low-induction iron measurements.

16. The apparatus for inspection of a gap as claimed in claim 8, wherein the storage roller comprises a return spring.

17. The apparatus for inspection of a gap as claimed in claim 1, wherein the mount comprises depressions, and wherein the magnets are each attached in a depression with adhesive.

18. The apparatus for inspection of a gap as claimed in claim 1, wherein the sensor platform comprises at least one instrument configured and arranged to grip and transport objects in the gap.

19. The apparatus for inspection of a gap as claimed in claim 1, wherein the sensor platform comprises at least one magnet embedded in the sensor platform and a material which can slide covering the at least one magnet, or a surface of said at least one magnet lies in a plane of a surface of the sensor platform.

20. The apparatus for inspection of a gap as claimed in claim 19, wherein the sensor platform comprises at least one movable magnet and a recess, wherein the at least one movable magnet is in said recess such that the at least one magnet is movable in a direction perpendicular to the longitudinal direction of the mount.

21. The apparatus for inspection of a gap as claimed in claim 1, wherein the sensor platform comprises a pivotable minor.

22. The apparatus for inspection of a gap as claimed in claim 1, further comprising:

a guide rail configured and arranged to stabilize the mount.

23. The apparatus for inspection of a gap as claimed in claim 1, wherein the mount is configured and arranged to be rolled out into an open configuration and is stiff when in said open configuration.