Ultrasonic in-line inspection system with square transducers

An ultrasonic pipeline crack inspection system comprising:

• a housing configured to be positioned within an internal volume defined by a pipeline flowing a fluid and having a circular cross-section, the housing configured to travel axially within the internal volume along a longitudinal axis of the pipeline, the housing comprising:
• an elongate body with a circular cross-section smaller than the circular cross-section of the pipeline, and
• a plurality of slots on a circumferential surface of the elongate body, the plurality of slots comprising:
• a first set of slots positioned at a first axial length along a longitudinal axis of the housing, and
• a second set of slots positioned at a second axial length along the longitudinal axis of the housing, the second axial length different than the first axial length, the second set of slots offset angularly from the first set of slots relative to the longitudinal axis of the housing;
• a plurality of square cross-section ultrasonic transducers (UTs) positioned in the plurality of slots on the circumferential surface of the elongate body, each square cross-section UT oriented and configured to transmit an ultrasonic beam away from the circumferential surface of the elongate body and configured to receive a reflection of the ultrasonic beam;
• wherein the ultrasonic beam transmitted by each square cross-section UT includes an ultrasonic beam profile with a cylindrical focal spot comprising inward contractions and outward expansions, wherein each square cross-section UT is oriented such that a corresponding focal spot of each square cross-section UT forms in the wall of the pipeline;
• and
• a controller operatively coupled to the plurality of square cross-section UTs, the controller comprising:
• one or more processors, and
• a non-transitory computer-readable medium storing instructions which, when executed by the one or more processors, cause the one or more processors to perform operations comprising:
• causing each UT of the plurality of square cross-section UTs to transmit a respective ultrasonic beam through the fluid flowed through the pipeline towards a wall of the pipeline,
• receiving, through the fluid flowed through the pipeline, a respective reflection of each ultrasonic beam transmitted by each square cross-section UT, and
• processing each respective ultrasonic beam and each respective reflection of each ultrasonic beam to analyze a crack in the wall of the pipeline.