Vibrating pig for measuring free spans, depth of cover
- Cambridge Univ. (United Kingdom). Engineering Dept.
Fast-moving ocean and river currents may generate large amplitudes of vibration in exposed and free-spanning pipelines leading to accelerated degradation of the pipeline. These currents are responsible for exposing the pipelines by shifting sand and mud on the sea floor. It is important to be able to locate exposed and spanning pipelines. For this purpose, external visual inspections are commonly carried out using submersible, remote-operated vehicles. These inspections can only take place during fair weather and where currents are not excessive. In some locations (fast-moving rivers, for example) it is not possible to inspect pipelines this way. A vibrating pig has been developed to identify variations in pipeline support by monitoring the variation along the pipeline of its response to transverse vibration. Vibration is generated inside the pig by using a rotating eccentric mass. Pipeline motion is measured with accelerometers mounted on board the pig. Variations in transverse pipeline motion are observed by the pig as it travels and these can be related to variations in pipeline support condition. As with conventional ultrasonic and magnetic-flux leakage (MFL) pigs, it is self-contained and free-swimming.
- OSTI ID:
- 438958
- Journal Information:
- Pipeline and Gas Journal, Vol. 223, Issue 8; Other Information: PBD: Aug 1996
- Country of Publication:
- United States
- Language:
- English
Similar Records
Corrosion pig minimizes shut down in German pipeline
Field experiences with intelligent pigs