Pipeline pig having gauging plate
AssigneeUnderground Location Services Limited
InventorTrevor C. Jones
Life of this patent
Estimating the term…
Abstract
A pipeline pig is equipped with a gauging plate which consists of a flexible disc having strain gauges secured thereto so as to be subject to deformation when the disc makes contact with an obstruction or deformation in the pipe wall. The strain gauges are connected in a bridge circuit which goes out of balance when the disc is deformed. The output of the bridge circuit is connected to means for producing an output signal when the disc is bent rapidly but not when it is bent slowly so as not to respond to slow deformation due to build-up of debris in front of the pig.
Claims12
A pipeline pig movable along a pipeline for detecting surface projections on the internal wall thereof which reduce the nominal internal cross-section of the pipeline by more than a predetermined amount comprising:
- a pig body
- a flexible disc of dimensions less by said predetermined amount than the nominal internal cross-section of the pipeline, said disc being mounted in its central region on said pig body so that the planar circular surfaces of said disc lie generally parallel to the cross-section of the pipeline;
- circular supporting means mounted on, and extending radially from, said pig body coaxially with said disc and having a radius larger than said disc for supporting said pig body in the pipeline with said disc substantially coaxial with the pipeline;
- a plurality of strain gauges secured to the peripheral region of said disc, said strain gauges being radially orientated outwardly with respect to the center of the disc;
- and
- circuit means coupled to the plurality of strain gauges and electrically responsive thereto for detecting bending of the peripheral region of said flexible disc responsive to striking internal surface projections.
Dependencies are inferred from the claim text.