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TOFD – In-line Inspection Service for Cracking
A key feature of our technology portfolio is the Time-of-Flight Diffraction (TOFD) solution. The TOFD method is the only existing in-line inspection technology capable of detecting and quantitatively sizing cracks in girth welds, seam welds and cracks originating from installations welded externally to a pipeline.
Time-of-Flight Diffraction technology
TOFD uses pairs of sensors, one acting as a transmitter and the other as a receiver. Broadband longitudinal ultrasonic waves are emitted and the generated sound field profiles are recorded and evaluated. The shortest connection between the transmitter and receiver is the surface wave (lateral wave), while the longest sound path is via the real wall (back wall echo). If no further signals occur, the material is free of defects. If echoes occur between the two signals, defects are present in the inspected volume. The ultrasound impulse impinging the defect generates new ultrasound waves at its edges (diffraction waves). These propagate spherically and also reach the receiving sensor, generating a corresponding signal.
- Real-time collection of pipeline data enables immediate decision-making
- Quantitative sizing of crack depths and accurate high-resolution data
- Preliminary report of pipeline integrity delivered on-site
- Avoid unnecessary costly repairs or replacement