Cut-off and leak-repairing device of air-bag-type pipeline

The utility model relates to a cut-off and leak-repairing device of an air-bag-type pipeline. The device comprises a screw thread pipe, a stop dog, a baffle, an air bag and a top rod. The screw thread pipe is installed at a pipeline welded junction needing to be welded, the stop dog is welded on the inner side wall of the pipeline opposite to the screw thread pipe, the baffle is inserted into the pipeline from the screw thread pipe, one end of the baffle is stuck on the stop dog, the air bag is provided with an external pipe with a gas filled tube valve, the air bag is crammed into the pipeline, and then the top rod is supported between the air bag and the baffle. According to the device, the air bag cut-off mode replaces an original mud cut-off mode, and the problems that a filter needs to be frequently cleaned, and container dredging labor intensity is large in the original mud cut-off mode are solved; and additionally, after leak-repairing operation of the device is carried out, the normal water injection