Apparatus for electromagnetically testing the walls of pipelines

US4769598A · kind A · utility

Assignee

• Kopp AG International Pipeline Services · DE

Inventors

• Gunther Krieg · Karlsruhe, DE
• Hartmut Goedecke · Weilburg, DE

Key dates

• Filing date: Mar 14, 1986
• Grant date: Sep 6, 1988
• Expiry date: Mar 14, 2006

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N27/902
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Apparatus for electromagnetically testing pipeline walls of steel or the like ferromagnetic material which is equipped, for example with a magnetizing coil for leakage-flux measurements, can be extended for ultrasonic measurement which is inductively excited and inductively measured with regard to the travel time as far as a reflecting surface and back, in the disposed in one or more of the pole regions there is a high-frequency current coil for the transmission and/or reception of steep-edged waves which are inductively coupled at the wall of the pipeline. The associated method starts from a stationary magnetic field in which high-frequency current pulses are produced in order to initiate vibrations in the pipe wall through induced currents. The travel time of these vibrations to a reflecting point and back can be measured in order to obtain an indication regarding the intact thickness of the pipe wall.