Abstract:
A method including the following steps: assembling sections of metal tube end-to-end so as to form an inner tube having a continuous passage for circulation of fluid; positioning a thermally insulating sleeve around each section of metal tube, the thermally insulating sleeve comprising at least one longitudinal groove; introducing a continuous functional line into at least two longitudinal grooves in at least two adjacent sections of tube; and filling in each longitudinal groove in order to cover the continuous functional line.