We have developed a fully automated gluing station for the simultaneous installation of three optical fibers on a pipeline at the 9, 12 and 3 o’clock positions. The three sensing cables retrieve the pipeline dislocation based on stimulated Brillouin scattering, providing the operator with a graphical 3D view of pipeline movements.
The automatic gluing system allows reducing the cost of installation, while at the same time minimizing positioning errors of the fibers along the pipe. While advancing along the pipe, the station does the
A. cleanses the surface of the pipeline, to remove grease marks or anything that may affect the quality of the bonding between the pipe and the fibers, B. applies a layer of adhesive along the surface of the pipeline, C. disposes, with controllable tension, the three optical fibers along the pipeline.
D. applies a protective coating.
The fibers are unwind from three separate spools, each one including an optoelectronic circuit for optical continuity assessment. In case of break of the fiber, the operator is immediately warned by the alarm system. While advancing along the pipe, the station keeps the horizontal asset thanks to an automatic balance system composed by two servomotors and an electronics platform including two gyroscopes for pitch and roll stabilization.
In this paper, we report the results of tests performed along a 12 m length of straight 6’’ pipeline, featuring three optical fibers glued using the developed station. After application of controlled bends to the instrumented pipe, the optical interrogator OSD-1 manufactured by Optosensing provides the strains for the computation of pipeline displacement, on the assumption that the pipeline is free of sectional and torsional strains. Comparison between imposed and measured displacements allowed us to assess the accuracy of the pipeline monitoring approach.