US Patent 7712521 Device of a test plug

A device is described for a plug (12) for pressure testing of bore holes and the like in a formation or the like, and associated pipe (10) in which the plug is installed in a plug-carrying chamber (14), and the plug (12) seals the passage through the pipe by cooperating with sealing bodies (23, 25), with the underside of the plug (12) being arranged (rests) in a seat at the bottom of the chamber. The plug is characterized in that it comprises a number of layer-formed or tier-formed ring disc elements of a given thickness, on fitted on top of the other.