Detection/salvage technique for saddle-shaped plate during stoppling operation of pipeline

The deformation of saddle-shaped plate or equipment fault will result in the submerging of saddle-shaped plate in pipeline in stoppling operation of pipeline. Therefore, a technical research on the detection/salvage method for the saddle-shaped plate was carried out. The salvage plan was composed of two steps in detection and salvage by means of detecting the locating the plate precisely. By comparison, the "visible detection+magnetizing" method was finalized. The high-pressure visible detection apparatus designed could accurately locate the distance and position of the plate shifted. The magnetic block was flexible enough to drag the plate out of the pipe. By a wide experimental study, the technique was appropriate for getting the plate with shifting length less than 1/3 pipe diameter. The technique was successfully applied in Dingyuan Gas Compressor Station, Westto-East Natural Gas Transmission Pipeline, saving the costs in pipe blowing-down for the salvage of saddle-shaped plate.