Patent ID: 8555930
Filing Date: 2013-10-15
Classification: F16L,Y10T

Abstract:
1. An assembly of at least two coaxial pipes constituted in a main portion by an outer pipe and an inner pipe defining an annular space preferably containing lagging material, the assembly being constituted by assembling together unit elements of at least two coaxial pipes, comprising at least two coaxial pipe assembly unit elements, one of which has, at at least one end, a first junction part joined to a second junction part at the end of another said coaxial pipe assembly unit element, each of said first and second junction parts being a body of revolution defined as follows: in a radial direction relative to a longitudinal axis XX′ of symmetry of said part, it is defined by a cylindrical inner wall of substantially the same diameter as the intermediate portion of said inner pipe, and by a cylindrical outer wall of diameter substantially equal to the outside diameter of the intermediate portion of said outer pipe; and in said direction of the longitudinal axis XX′ the ends of said two non-welded-together inner second branches of said first and second junction parts are in metal-on-metal contact with each other under elastic deformation stress via their contact surface, which is a surface of revolution, between an outer first surface of revolution on the outer face of the inner second branch of the first junction part and an inner second surface of revolution on the inner face of the inner second branch of the second junction part, said inner second branch of the first junction part forming a male inner second branch situated inside the female inner second branch of the second junction part, wherein said inner second surface of revolution is of a shape that is different, but of the same axis of revolution as the outer first surface of revolution, such that said outer first surface of revolution and inner second surface of revolution present, when they are arranged coaxially and engaged in contact one against the other, an initial line of contact that is circular and that transforms into said contact surface after said elastic deformation stress resulting from the elastic deformation due to the shrinkage of the weld between the ends of said outer second branches of said two junction parts, so that said internal second cavities are leaktight relative to the inside of the inner pipe.