Pipeline operators use a wide variety of methods, inspect and monitor the hundreds of thousands of miles of transmission pipeline now in operation worldwide. Such activities include right of way surveys, catholic protection surveys, leak detection surveys, leak detection programs, excavations to look for pipe corrosion or protective coating failures, hydrostatic tests, and the use of in-line inspection tools that travel through the pipe. Combinations of these procedures constitute an overall integrity assurance program of the pipeline operator.
Magnetic flux leakage (MFL) is the oldest and most commonly used in line inspection method for finding metal-loss regions in gas-transmission pipeline . MFL can reliably detect metal loss due to corrosion and, sometimes, gouging. In addition, while not designed for this purpose, MFL can sometimes find other metallurgical and geometric conditions.
The VEDAQ -FL is a PC- based, portable, high performance EMI system designed to inspect flow lines that are located above ground and NOT buried pipeline. The flow line is
inspected between the supports that hold the pipe off the ground. The mag coil, " buggy " and "detector heads " are split with a hinge (clamshell type) and can be removed
and installed on the pipeline without cutting the pipe. A travelling motorized " buggy " propels the detector head along the pipe , detecting 3D transverse flaws such as
pitting, cracks and corrosion, while the True- Wall magnetic wall system monitors the wall thickness, detecting larger areas of wall loss, i.e. corrosion..
Inspection data is displayed in "real time" on the laptop computer and the data is stored to the hard drive. The data can be copied or transmitted by wireless. Calibration of the system is recommended to be performed on a clean tube similar in size and weight as the pipe being inspected. Standards normally have 1/16 drill thru holes and a 5% or 10% wall loss, which should be sufficient to set the system up to detect typical pitting and corrosion in flow lines located above ground. |
