Device for the non-destructive testing of ferromagnetic bodies and a process for producing values for adjusting the device into an initial state for testing determined by the respective test samples

US4750134A · kind A · utility

Assignee

• Nukem, LLC · DE

Inventors

• Gerhard Huschelrath · Laufach, DE
• Herbert Diehl · Leverkusen, DE

Key dates

• Filing date: Dec 9, 1985
• Grant date: Jun 7, 1988
• Expiry date: Dec 9, 2005

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N27/82
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

This invention provides for the non-destructive testing of a longitudinally displaceable ferromagnetic body for structural faults. This device sends a stationary magnetic field transversely across the body of the test piece. Changes in this magnetic field, due to structural defects of the test piece, are detected by the magnetic field detectors which are placed on the periphery of the test piece in alignment with the stationary magnetic field. The changes detected by the magnetic field detectors must be processed in order to be useful. This processing requires compensation for the varying strength of the magnetic field at the surface of each different magnetic field detector, compensation for unequal sensitivities of each individual magnetic field detector in detecting structural defects, and also compensating for the tolerances of circuits which are used in the previous compensations.