Removable pipeline plug

Claim 1

In combination with a steam pipeline of a boiling water reactor, a removable pipeline plug assembly comprising: (a) a plug body, (b) two redundant annular members surrounding said body each having a deflated diameter less than and an inflated diameter greater than the interior pipeline dimensions, (c) two redundant annular arrays of hydraulic pistons extending radially from said body and alternating in the same plane, (d) rigid arcuate metal shoes radially and independently translatable by the respective pistons between retracted positions adapted to clear the pipeline interior and extended positions therebeyond, (e) pivotal mounting means permitting infinitely variable positioning of each shoe on its piston for self-adjusting substantially flush engagement with even out-of-round pipeline interiors, (f) a detachable tool for inserting and withdrawing the plug from a selected variable position within the pipeline with the inflatable member deflated and the shoes retracted, (g) hydraulic means for actuating the pistons and extending the shoes into engagement of substantially predetermined force with the pipeline interior to fix the plug within the pipeline, (h) pneumatic pressurizing means for inflating the inflatable member of the inserted plug into resilient forcible annular sealing contact with the pipeline interior, and (i) valved conduit means for introducing a pressurized test fluid through and forward of the plug body and for venting fluids back through the plug body.