A plug inserted in a pipeline to stop the flow of oil while repairs are being made a specially designed plug inserted in a pipeline through the use of a tapping machine (q.v.). In making a pipeline repair, cutting out a short section of the pipe, for example, the pump is shut down and the line is drained as completely as possible. But when the pipe is cut some oil may still be draining from a higher level of the line. To block this drainage a stoppel or plug is put in. On small-diameter lines. 12-inch or smaller mud is packed in the end of the line to dim up the drainage, when the line is repaired the pump is started and the mud plug is pushed along inside the line. It disintegrates and will end up either in a storage tank or at a scraper trap. On large-diameter lines, an inflatable rubber sphere is inserted in the cut line and inflated with compressed air. The sphere effectively fills the line and makes a good dam. When the repair is made, pumping is resumed and the inflated sphere is pushed ahead to take-off point just as a batching sphere (q.v.).
