SYSTEM FOR THE INTERNAL INSPECTION OF PIPELINES

SYSTEM FOR THE INTERNAL INSPECTION OF PIPELINES A system for the internal inspection of pipelines for carrying oil or gas, subsea or overland, includes an apparatus carrier, pressuredriven or self-propelled, carrying non-destructive examination apparatus moved through the pipeline to inspect the safety conditions of the pipeline wall material and surfaces. During its progression the carrier gradually deposits one or more expendable, thin optical fibres inside the pipeline. the fibres connect the carrier with a control station, situated outside the pipeline at the carrier launching end of the pipeline, through electro-optical signal converters installed in the carrier and in the control station. The system permits continuous on-line communication with the carrier over very long distances (1) for generating instant visual displays and permanent records of the stepby-step results of the inspection, (2) for controlling the functions of the non-destructive examination apparatus, and (3) for controlling the rate of progression of the carrier. Upon completion of the inspection the optical fibres are discarded inside the pipeline for later removal, if necessary, by a routine in-service cleaning operation.