FIELD: machine building.
SUBSTANCE: procedure for fabrication of insulated unit "pipe-in-pipe" consists in following stages: in facilitating unit containing at least one internal pipe and external pipe surrounding at least one internal pipe creating circular space between external surface of at least one internal pipe and internal surface of external pipe. There is also at least one container located in circular space. It contains porous flexible volumetric compressed material of porous particles. It is compressed in the container and has the first volume less, than volume of not compressed material. The procedure also consists in change of at least one container to reduce compression of compressed material to the second volume exceeding the first volume, thus creating an insulating unit "pipe-in-pipe". There are also disclosed versions of the insulating unit "pipe-in-pipe".
EFFECT: improved heat insulation of pipelines.
