Apparatus for electrically detecting discontinuities in electrically nonconductive coatings on electrically conductive materials

Claim 1

AN APPARATUS FOR ELECTRICALLY INSPECTING A SUBSTANTIALLY NON-CONDUCTIVE INTERNAL COATING ON AN ELECTRICALLY CONDUCTIVE PIPE COMPRISING: A PIPE SUPPORT FOR SUPPORTING SAID PIPE DURING INSPECTION, A LANCE SUPPORT FRAME POSITIONED AXIALLY FROM THE END OF SAID PIPE SUPPORT AND COMPRISING A CANTILEVERED LANCE MOUNTED ON SAID LANCE SUPPORT FRAME, AN ELECTROLYTE RESERVOIR CONNECTED TO SAID LANCE SUPPORT FRAME AND ELECTRICALLY INSULATED THEREFROM, A SCANNING HEAD MOUNTED UPON SAID LANCE NEAR THE UNSUPPORTED END THEREOF AND COMPRISING AN ARCUATE MEMBER OF POROUS MATERIAL WETTED WITH AN ELECTROLYTE AND OF A SIZE TO RESILIENTLY CONTACT THE INTERNAL SURFACE OF SAID PIPE, A FLUID CONDUIT CONNECTING SAID RESERVOIR AND SAID ARCUATE MEMBER FOR CONTROLLABLY SUPPLYING ELECTROLYTE TO SAID ARCUATE MEMBER, AN INDICATOR CONNECTED IN SERIES WITH SAID PIPE AND SAID ARCUATE MEMBER TO FORM A CIRCUIT HAVING AN ELECTRICAL PORTENTIAL SUPPLIED THERETO WHEREBY CURRENT FLOWS THEREIN WHEN SAID ARCUATE MEMBER ENGAGES A HOLE IN SAID COATING, A POWDERED CARRIAGE MEANS ATTACHED TO SAID APPARATUS FOR EFFECTING RELATIVE RECIPROCAL AXIAL MOVEMENT OF SAID ARCUATE MEMBER THROUGH SAID PIPE.