ALD® Vertical inspection mode

In the ALD® vertical mode, the sensor is lowered underneath the survey vessel by mean of a wire line kept vertical by a clump weight (CW). The CW keeps the wire line vertical and the sensor oriented downwards. The POD is also fixed to the clump and data reaches the surface trough a soft cable fixed to the wire line.

This technique allows an accurate inspection of pipelines, flanges or valves without the need of divers or ROV. It is recommended for conditions where depth and current make critical the navigation of the towed fish. Suitable for a depth range of 30-150m. The vessel shall be equipped with a dynamic positioning system and a USBL.

Features

The system is mainly composed by an underwater acoustic sensor, a POD (underwater electronic unit), a transmission line, a receiving unit and a PC based processing and display software. The sensor and the transmission line are different depending on the inspection techniques while the other components are common to all applications: while the sensor is driven along the pipeline or positioned close to a flange or connection, the receiver puts the operator in condition of identifying an eventual leak signal.