Stopper for sealing stepped bore under pressure fits into wider section of bore and transitional section between this and its narrow part and has central bore containing ball which presses it against bore

摘要

The stopper (2) for sealing a stepped bore which is under pressure fits into the wider section (6) of the bore and the transitional section (8) between this and its narrow part (7). The stopper has a central bore (4) containing a ball (3) which presses its walls against those of the bore. An Independent claim is included for a method of sealing a bore using the stopper.