NON-DESTRUCTIVE EVALUATION OF PIPES AND TUBES USING MAGNETOSTRICTIVE SENSORS

• Main Authors: TELLER, CECIL M., II, KWUN, HEGEON
• Format: Patent
• Language: English; French
• Published: 19.09.1996
• Edition: 6
• Subjects: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; PHYSICS; TESTING

A method and apparatus for the inspection of ferromagnetic and nonferromagnetic pipes (14) or other cylindrical shell structures utilizing the magnetostrictive effect to detect defects within the structure. The invention constitutes an active testing application, wherein a transmitting coil element (16) generates a mechanical pulse (15) within a cylindrical shell structure through the magnetostrictive effect and a second coil (24) detects reflected mechanical waves (15) within the pipe, or a single sensor (10) functions as both transmitter and detector. The present invention also anticipates a passive monitoring application with a detection coil (16) that continuously monitors ferromagnetic or non-ferromagnetic cylindrical structures for mechanical or acoustic wave emissions (15). Non-ferromagnetic structures (14) are made amenable to inspection by attaching a layer of ferromagnetic material such as nickel on a wall of the structure by plating or bonding such material in a local area where the sensor is to be placed.