Expandable tube plug

Claim 1

In a heat exchanger tube plugging system of the type in which a radially expandable plug is inserted, in its unexpanded state, into one end of the heat exchanger tube, moved within the tube to a location adjacent the remote end thereof and, subsequently, rotated by means of a tool engaging the plug and extending outwardly from the one end of the tube to effect expansion of the plug and sealing of the tube, the improved tube plug comprising: a first metal cylindrical body having a longitudinal axis, first and second ends each perpendicular to the longitudinal axis and a threaded bore extending inwardly from the first end and coaxial with the body, the external diameter of the body being less than the internal diameter of the heat exchanger tube; a second metal cylindrical body having a longitudinal axis, first and second ends each perpendicular to the longitudinal axis and a through bore coaxial with the body, the external diameter of the second body being less than the internal diameter of the heat exchanger tube, the diameter of the through bore being slightly greater than the diameter of the threaded bore of the first body member; a compressible cylindrical sleeve having a longitudinal axis, first and second ends each perpendicular to the longitudinal axis and a coaxial through bore, the external diameter of the sleeve in its uncompressed state being less than the internal diameter of the heat exchanger tube, the diameter of the through bore of the sleeve in its uncompressed state being slightly greater than the diameter of the threaded bore of the first body member, the sleeve being positioned between the first and second body members with the axes of the bodies and the sleeve being colinear; a bolt having a head engageable by the tool and a threaded shank, the shank passing through the bores of the second body member and the sleeve and threading into the bore of the first body member, the head of the bolt bearing against the first end of the second body member; a metal disc having a knurled circumferential surface and a diameter approximately equal to the external diameter of the first body member; and means mounting the disc on the second end of the first body member for pivotal movement about an axis parallel to but offset from the longitudinal axis of the first body member, the arrangement being such that, upon initial rotation of the bolt when the plug is at the location adjacent the remote end of the tube, the metal disc engages the tube wall locking the first body member against rotation so that with continued rotation of the bolt, the bolt threads into the bore of the first body member to effect compression of the sleeve between the first and second body members forcing expansion of the sleeve outwardly into sealing engagement with the tube wall and inwardly into sealing engagement with the bolt shank preventing fluid movement therealong.