Demo: measuring the displacements of a pipelineelixandre
Distributed measurements of strain and temperature by means of optical fiber: measurement of pipeline shape.
Cementys is proud to demonstrate its new distributed Strain and Temperature monitoring technologies based on Raman and Brillouin Optical Backscattered Time Domain Reflectometries.
Distributed strain and temperature allow to measure the displacement of a pipeline under flexion. To do so, Cementys needs at least 1 meter of fiber laid down either helicoidally or following 3 straight line at 120° around the pipe. To present both methods, two 13 meters long pipelines are respectively equipped with 3 straight fibers at 120 and with an helicoidal fiber.
2 different interrogation boxes are used, measuring different physical effects: one for the Brillouin effect (sensitive to temperature and strain) and the other for the Raman effect (sensitive only to temperature). By combining information, we can deduce the variation of strain due to mechanical stresses and the absolute temperature of the pipe, with a measurement every 50cm.
The experimental measurements of the amplitude and the direction of bending deflection are done real-time. Fiber optic being capable of long range measurements, remote locations can be interrogated (up to 40 miles).
The SensoluxTM® cable containing 4 tight buffered fibers (2 singlemode and 2 multimode) allows such measurements. Once attached to the pipeline with epoxy glue or equivalent adhesive, all the mechanical strains and temperature changes seen by the structure are fully transmitted to the optical fibers, and so detected by the interrogators.
Eventually, this instrumentation gives information on the mechanical strains all along the structure in real time.