Patent ID: 6314795
Filing Date: 2001-11-13
Classification: G01M

Abstract:
A method of leak detection in a pipeline in which fluid can be conveyed along the pipeline by a pressure differential in the fluid established between a first and a second part of the pipeline, the method comprising the steps of:reducing the pressure differential;providing an opening in the pipeline between the first part and second part to allow access to the interior of the pipeline;introducing into the pipeline, by way of the opening, an initially loose fitting plug having an expandable periphery adapted for inflation by means of a flexible pipe connected to a first end of the plug, the expendable periphery formed integrally with a front section of the plug located at a second opposite end of the plug, the expansion of the expandable periphery leading to corresponding expansion of the front section of the plug;providing tracing means along the length of the flexible pipe whereby the path of the flexible pipe and the plug can be detected remotely, at least while within the pipeline;closing the opening in the pipeline to restore the ability of the pipeline to maintain the pressure differential between the first part and second part;allowing the plug to be driven along the pipeline by the fluid pressure differential established across the plug while limiting motion of the plug by means of the flexible pipe;inflating the expandable periphery of the plug so as to drive the expandable periphery (21) into fluid tight engagement with a wall of the pipeline so as to substantially block the flow of fluid along the pipeline from an upstream side of the plug to a downstream side and cause the plug to be locked in position within the pipeline;establishing either:whether fluid pressure in the pipeline upstream of the plug, remains constant, implying that no leakage exists upstream of the plug between the plug and the first part of the pipeline; orfalls, implying that a leak through the pipeline wall exists between the plug and the first part of the pipeline; andremotely detecting the position of the plug in the pipe via the tracing means while the plug is locked in position and relating that position of the plug to the position of the leak.