Abstract: An obstacle detecting pig for preliminary inspection of a section of a pipeline travels through the section and determines if there are any restrictions that exceed industry guidelines or that might damage other pigs that require the full bore of the pipe. In a first embodiment, a disk-shaped segmented resilient member (14) is mounted in the body of the pig. Its outside diameter is smaller by a spacing (21) than the inside diameter of the pipeline (15). The spacing is set at the maximum tolerable size of the obstacle encountered. The deformation of the member (14) is transmitted by a linkage (22) to a slider (16) activating a switch system signaling that an obstacle has been encountered. A non-resiliently deformable checkup disk (19) may be provided at the rear end of the pig, to double check that a no-signal passage through the pipe is not due to failure of the switching system.

Abstract: An obstacle detecting pig for preliminary inspection of a section of a pipeline travels through the section and determines if there are any restrictions that exceed industry guidelines or that might damage other pigs that require the full bore of the pipe. In a first embodiment, a disk-shaped segmented resilient member (14) is mounted in the body of the pig. Its outside diameter is smaller by a spacing (21) than the inside diameter of the pipeline (15). The spacing is set at the maximum tolerable size of the obstacle encountered. The deformation of the member (14) is transmitted by a linkage (22) to a slider (16) activating a switch system signaling that an obstacle has been encountered. A non-resiliently deformable checkup disk (19) may be provided at the rear end of the pig, to double check that a no-signal passage through the pipe is not due to failure of the switching system.