Device for thermal insulation of at least a submarine pipeline comprising a phase-change material confined in jackets

A device for thermally insulating at least one undersea pipe. The device comprises a thermally insulating covering surrounding the pipe, the covering being covered by an outer leak proof protective case, and the case being made of a flexible or semi rigid material suitable for remaining in contact with the outside surface of the insulating covering when it deforms. The device is characterized in that the insulating covering comprises a phase-change material confined in at least one container made of a flexible or semi rigid material that is deformable, and the container is disposed around the pipe.