Method and device for detecting a small leak in the submerged part of the lining of the wall of a liquid tank

摘要

An open dome-shaped enclosure 6 is disposed against the external surface of the lining 1, inside the liquid and in the zone to be monitored, by means of the periphery 10 of its opening fitted with a seal. A partial vacuum is created within the enclosure and a beam of ultrasonic waves is sent through the enclosure 6 at its upper part, then the ultrasonic beam is picked up and its attenuation after having passed through the enclosure 6 is measured. In the case of a leak, air bubbles passing through the lining 1 cause attenuation of the ultrasound. <IMAGE>