METHOD OF INTRATUBE ULTRASONIC DIAGNOSTICS OF CONDITION OF PIPE-LINE Russian patent published in 2000 - IPC

FIELD: non-destructive testing, flaw detection in main oil and gas pipe- line in process of their operation. SUBSTANCE: invention allows all types of flaws to be exposed with provision for ultrasonic probing over entire length of circumference of pipe-line wall with minimal number of electroacoustic converters. Method involves uninterrupted movement of flaw detector with electroacoustic converter along pipe-line wall, generation of pulses of ultrasonic vibrations by electroacoustic converter, contact-free transmission of pulses of ultrasonic vibrations through pumped over medium into pipe-line wall, excitation of ultrasonic vibrations in pipe-line wall, reflection of ultrasonic vibrations from inhomogeneities of material of pipe-line wall, transmission of reflected ultrasonic vibrations from pipe-line wall to electroacoustic converter, recording of reflected ultrasonic vibrations and determination of characters, sizes and locations of flaws in pipe-line wall by measurement results. Solid waveguide whose acoustic characteristic match those of pipe-line wall is used in this process. It is moved equidistantly from surface of pipe-line wall. While transmitting ultrasonic vibrations into pipe-line wall ultrasonic Lamb wave is excited in waveguide and pencil beam of ultrasonic Lamb wave oriented along waveguide and synchronized with Lamb wave in waveguide is formed in pipe-line wall. While transmitting ultrasonic vibrations reflected by inhomogeneity of material of wall into electroacoustic converter backward ultrasonic Lamb wave is scanned by waveguide and own ultrasonic Lamb wave whose amplitude-frequency characteristic is similar to amplitude-frequency characteristic of backward Lamb wave in pipe-line wall and is synchronized with it is generated in waveguide. Parameters of ultrasonic Lamb wave in waveguide are recorded by electroacoustic converter. EFFECT: improved authenticity of detection of all types of flaws in walls of pipe-line. 7 cl, 4 dwg