Abstract: Resilient stoppers are temporarily compressed and are inserted into tubular conduits and then released to expand therein to stop fluid leakage therefrom. Tapered stoppers larger across than tubes to be plugged are inserted by a tapered hollow tool having a large end to receive a stopper and a smaller end inserted within a tubular conduit to be plugged. Application of pressure to the base of the stopper to force it through the tapered tool also compresses it to a temporarily lesser size. Upon leaving the tool end inside the tube, the stopper expands into non-slipping contact with the surrounding wall. Continued pressure, rather than sliding the stopper in the tube, backs the tool end away and out therefrom, leaving the stopper plugging the tube.

Abstract: Resilient stopper rings are inserted into a tubular conduit and are compressed endwise so as to expand outwardly against the conduit wall to block or stop flow or leakage of fluid from the conduit. In operation, axial spacing of stopper leading and trailing cylindrical end parts threaded together and sandwiching the rings is adjusted by a wrench to compress the rings to plug the conduit or alternatively to release the rings for removal of the stopper from the conduit.