Electromagnetic Acoustic Transducer (EMAT)
Electromagnetic Acoustic Transducer (EMAT) technology is a non-destructive testing (NDT) method for inspection of pipelines and other structures without the need of a couplant material.
Traditionally, ultrasonic testing (UT) methods involve the use of piezoelectric transducers that rely on the conversion of electrical energy into mechanical vibrations to generate sound waves in a material. These sound waves then propagate through the material, and their reflections are used to detect defects or abnormalities. In case of gas carrying pipelines there is no liquid couplant for transmission of ultrasonic waves to and from the sensors.
EMAT technology overcomes this limitation by utilizing the electromagnetic interaction between the transducer and the material being tested. Instead of relying on mechanical coupling, EMATs use electromagnetic coils to generate and detect ultrasonic waves directly in the material being tested, such as the pipeline wall.
PIG trackers are installed in Inspection Tools to track their travel through the pipeline. The inspection team carries special receivers that are tuned to capture the signal from PIG trackers.
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Transmitter: Transmitter installed on the PIG emits electromagnetic wave of a particular frequency.
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Antenna & Receiver: The waves transmitted by the transmitter are sensed by antenna & receiver set. The passage of PIG from a location is indicated on the receiver screen.