Rotary probe apparatus for detecting flaws in a test object
US4641092A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 5, 1983 |
| Grant date | Feb 3, 1987 |
| Priority date | — |
| Expiry date | Jul 5, 2003 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB21B38/00
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A flaw detection apparatus for detecting flaws at the outer surface of a product, such as a steel bar, wire or steel pipe, which is round in section and produced by the hot rolling, by use of a probe of non-contact type and rotating around the product to be inspected, the apparatus providing a means for suppressing vibrations of an object to be inspected, a means for measuring a distance (lift-off) between the object to be inspected and the probe, and a means for carrying out positional control on the basis of the detection result of the lift-off measurement so that the axis of rotation of probe is allowed to be coincident with the axis of object to be inspected. In a case of using the eddy current inspection for the flaw detection, two coils of standard comparison system are used and a mixed signal of a plurality of frequencies is applied to the coils so that a signal obtained by the probe coils suppresses the signal component caused by the lift-off variation and corrects the flaw signal caused by existence of the signal component, thereby eliminating the influence of lift-off variation and enabling measurement with high accuracy.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.