Page 309 - Pipeline Pigging Technology

Pipeline Pigging Technology

Fig.4. Probes staggered to provide full-sector coverage.
section being inspected from the sea as shown in Figs 9 and 10. In all cases,
detachable spoolpieces or launch traps were used to deploy the PIT.

2. The RTD PIT 6000

In order to inspect long off-loading pipelines in one run, preferably from
the shore, the PIT 6000 has been designed and is under construction. Basically
it uses the same design and construction as the PIT 2000, although as it is
almost impossible to increase the length of the 2000-m long conventional
cable, it was decided to replace all the copper signal wires in the "galvanic"
cable by glass-fibre technology. Experiments have shown that signal transmis-
sion for distances over 15,000m is feasible.
For signal transmission, the new cable consist of only a few glass fibres, and
is reinforced with aramide fibres to provide a tensile strength of 5000kg. The
cable, including a low-friction outer coating, has less than half the diameter

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