Method and apparatus for inspecting conduits

An ultrasonic inspection method of inspecting an area of a conduit to detect a defect or a deposit, which comprises the steps of:

• a) positioning a probe inside said conduit, said probe comprising a pair of ultrasonic transceivers positioned on said probe such that said transceivers are on either side of and substantially equidistant from said area;
• b) directing a first ultrasonic pulse, from a first transceiver of said pair, at said area of the conduit, from a first direction axially forward of said area;
• and substantially simultaneously directing a second ultrasonic pulse, from a second transceiver of said pair, at said area of the conduit, from a second direction axially rearward of said area;
• c) receiving at said first transceiver reflected sound signals caused by reflection of said first ultrasonic pulse from said area;
• d) receiving at said second transceiver reflected sound signals caused by reflection of said second ultrasonic pulse from said area;
• e) plotting said reflected sound signals versus time, wherein a defect is distinguished from a deposit and identified by observing overlap of signal patterns produced by both said transceivers, indicating that said reflected sound is received at the same time by both said transceivers.