METHOD OF LOCATING DEFECTS IN WALLS OF OIL AND GAS PIPE LINES AND CHECKING EXTERNAL INSULATION FOR CONDITION Russian patent published in 1998 - IPC

FIELD: nondestructive testing systems; locating flaws in hard-to-get-at areas of pipe lines. SUBSTANCE: transmitting and receiving converters on base of piezoceramic elements are placed inside pipe lines at distance of no less than ten linear sizes of contact area of bearing roller with converter and surface under test; then acoustic signal at low resonance frequency is radiated by transmitting converter through acoustically aligned medium for condition of surrounding air medium, after which this acoustic signal is received at point where receiving converter is located through acoustically aligned medium and comparative analysis of change in amplitude and spectrum of received signal for air and real media is conducted. EFFECT: enhanced reliability of diagnosis. 2 cl, 5 dwg