Patent ID: 7011244

Claim:
A centering insert device for centering two pipe elements for welding together end to end, the insert being suitable for being inserted inside said pipe elements in register with the ends of said pipe elements that are to be welded together, said centering insert device comprising a main body which extends longitudinally substantially along the axis of said pipe; said main body supporting a plurality of clamps each comprising a thrust block suitable for being actuated by a thruster device; said thrust blocks being capable of moving in translation in a radial direction relative to the longitudinal axis from a retracted position remote from the inside wall of said pipe to a position in which said thrust block comes into abutment against said pipe wall; said thrust blocks being disposed in a plurality of centering planes corresponding to section planes; there being at least three of said thrust blocks in each of said planes in a regular angular distribution about said longitudinal axis; the centering insert being characterized in that said clamps comprise independent clamps disposed in at least one end section plane, said thrust blocks of said independent clamps being suitable for moving in translation in said radial direction independently of one another and in non-uniform manner, the power of their respective thruster devices being limited so that when the first thrust blocks come into abutment against the inside wall of said pipe, they cease moving while the other thrust blocks in the same end section plane which are not yet in contact continue to move until they in turn come into abutment against said inside wall, said independent clamps of said end plane thus being suitable for being blocked against the inside wall of said pipe so as to freeze the shape of the pipe in its initial state at said end plane, without deforming the pipe.