Patent ID: 8794675

Claim:
A coaxial pipe element comprising: an inner pipe; an outer pipe spaced from said inner pipe, thereby forming an annular space therebetween; and a sealed closure positioned at each end of said inner and outer pipes and annular space, each said sealed closure being constituted by a junction forging in the form of a body of revolution, each of said junction forgings being constituted as a single integral block for joining with another coaxial pipe element, each of said junction forgings comprising at least two first branches of revolution, in which an inner first branch of revolution is welded directly to one end of said inner pipe with a circular weld bead and an outer first branch is welded directly to the end of said outer pipe with a circular weld bead, said inner first branches of revolution being longer than said outer first branches by a length L, in the axial longitudinal direction of said coaxial pipe element, each of said junction forgings at each end of said pipe element being designed to be assembled at one end to the ends of said outer and inner pipes of said coaxial pipe element, and at an opposite end directly to another said junction forging, itself assembled by welding to the end of another or second unit comprising two coaxial pipes, wherein, all of said circular weld beads are located on the outside of the inner and outer pipes, and wherein each respective end of the outer pipe is connected to the respective sealed closure by a single weld and there are no intervening welds on the outer pipe.