INSPECTION OF COATING CONDITION OF FOAMING LIQUID FOR TESTING LEAKAGE

PURPOSE:To enable accurate inspection even when an object to be inspected is large by using an elastic circular piezo-electric sensor incorporating a circular polymer piezo-electric element flexible to scan the surface of an object desired to test leakage. CONSTITUTION:A foaming liquid 7 for testing leakage is blown to the external surface of a weld part 5 via the inside of a circular part of an elastic circular piezo-electric sensor 13 incorporating a circular polymer piezo-electric element 20 flexible from a sprayer 14. Then, an ultrasonic wave is radiated to the weld part 5 from the sensor 13. If after a coating of the liquid 7, the ultrasonic wave reaches an internal wall surface 16 of a pressure container 1, from which it is reflected to the sensor 13. The presence of the reflected ultrasonic wave is detected with the sensor 13 and a detection signal is sent to an ultrasonic detector 23 to be displayed on a cathode ray tube 24 as internal echo. It is also observed with a TV camera 17. Elasticity imparted to the sensor 13 helps make the sensor 13 along a curved surface and a rugged part of the container 1.