Patent attributes
A pipeline pig includes a plurality of relief channels and a bypass channel extending therethrough. To regulate a speed of the pipeline pig, relief valves within the relief channels open when a differential pressure between upstream and downstream ends of the pipeline pig reaches a pre-selected minimum relief pressure. If the differential pressure reaches a pre-selected maximum relief pressure, such as when the pipeline pig encounters an obstruction, the relief valves close to allow the differential pressure to further increase to clear the obstruction. If the further increase in differential pressure is insufficient to clear the obstruction and the differential pressure reaches a pre-selected minimum bypass pressure, a bypass valve opens to permit fluid flow through the bypass channel while the relief valves are closed. Flow through the bypass channel operates to reduce turbulence and permit production through the pipeline if the pipeline pig becomes stuck and obstructs the pipeline.
