Mannesmann Aktiengesellschaft

Wolfgang Boettger

Heinz Schneider

Willi Weingarten

Friedhelm Schlawne

Electrically conductive work pieces such as steel tubes or pipes are tested by means of a transducer comprised of a row of magnetic pole pieces through which a dc flux pattern of alternating polarity and direction is set up along a line of pole extensions and through which bidirectional ac ultrasonic transmission takes place to discover defects which return ultrasonic pulses.

Nondestructive testing

An electrodynamic transducing device includes two staggerdly coils with a distance of staggering equal to a quarter of a wavelength of ultrasonic waves; unidirectional transmission characteristics of the transducer is obtained by feeding the two coils separately with HF current at a time difference of feeding of the respective two signals to be equal to a quarter of the wavelength such that a reinforcing ultrasonic signal is produced in the direction of the coil receiving said signal earlier in time and complete cancelation of acoustic waves obtains in the opposite direction, whereby in case of equal pitch of said coils the HF signals are of equal contour but of opposite polarity while in case of opposite winding pitch the signals not only have equal signal contour but also the same polarity.

Growing community of inventors

Duesseldorf, Germany

Wolfgang Boettger