Abstract: A pipe-in-pipe assembly comprises a bundled infill structure occupying an annulus between inner and outer pipes (12, 26) of the assembly. The infill structure is formed of a plurality of elongate elements laid along the inner pipe comprising a mixture of reinforcing elements (16B) and insulating elements (16A). The reinforcing elements have greater mechanical resistance than the insulating elements to radial compression whereas the insulating elements provide greater thermal insulation than the reinforcing elements. Pluralities of the reinforcing elements are positioned together within the infill structure to form reinforcing formations, such as spacer formations, embedded between insulating regions of the infill structure that are defined by pluralities of the insulating elements.

Abstract: A thermally insulating undersea junction pipe providing a junction between two thermally insulating undersea pipe portions. The junction pipe having a rigid bent inner pipe and presenting a radius of curvature that is three to ten times its outside diameter and coated in a thermally insulating material. The junction pipe having an outer jacket surrounding the inner pipe, the jacket being made of flexible or semirigid material matching the bent shape of the inner pipe in coaxial manner The tubular wall of the outer jacket including structural reinforcing elements of annular or helical shape suitable for enabling the tubular wall of the outer jacket to be bent while keeping its cross-section substantially uniform. A quasi incompressible thermally insulating material in the form of a gel is disposed to completely filling the annular space between the inner pipe and the outer jacket.

Abstract: A thermally insulating undersea junction pipe providing a junction between two thermally insulating undersea pipe portions. The junction pipe having a rigid bent inner pipe and presenting a radius of curvature that is three to ten times its outside diameter and coated in a thermally insulating material. The junction pipe having an outer jacket surrounding the inner pipe, the jacket being made of flexible or semirigid material matching the bent shape of the inner pipe in coaxial manner The tubular wall of the outer jacket including structural reinforcing elements of annular or helical shape suitable for enabling the tubular wall of the outer jacket to be bent while keeping its cross-section substantially uniform. A quasi incompressible thermally insulating material in the form of a gel is disposed to completely filling the annular space between the inner pipe and the outer jacket.