SETT OCH ANORDNING FOR ICKE-FORSTORANDE TESTNING AV EN FYSISK EGENSKAP HOS ETT LJUSABSORBERANDE ARBETSTYCKE

摘要

A method and device which measures the velocity of ultrasonic waves in a moving web is disclosed. The excitation source is a laser or other device which produces short intense light pulses and the detection system is either a piezoelectric transducer or a microphone. The latter obviates any need for physical contact with the web in order to carry out tests for strength parameters as the web is manufactured.