Ultrasonic measuring process for the wall thickness curve of a weld seam of a pipe

US5583292A · kind A · utility

Assignee

• Krautkramer GmbH & Co. · DE

Inventors

• Bernhard Karbach · Lechenich, DE
• Siegmar Schulz · Cologne, DE
• Peter Steinert · Kerpen, DE

Key dates

• Filing date: Sep 23, 1993
• Grant date: Dec 10, 1996
• Expiry date: Sep 23, 2013

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N2291/048
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An ultrasonic measuring process is disclosed for measuring the wall thickness variation in the region of the welding seam of a pipe. At least two testing heads are each acoustically coupled to the pipe by a water jet. The acoustic entry zones of the testing heads are moved together in relation to the pipe, parallel to the axis of the pipe. At least one of the testing heads is moved back and forth across the axis of the tube, crossing over the welding seam. The acoustic entry zone can be moved by modulation of a phased array. The second testing head either emits acoustic radiation into the pipe always outside the welding seam or also crosses the welding seam, but at different times than the first testing head. The signals of both testing heads are processed in a measurement value processing circuit such that simultaneously occurring measurement value deviations supply no output signal.