Tank for transporting liquefied gases by sea - incorporates fluid tightness and insulating barriers simply realised, necessitating only small sweeping nitrogen flow

摘要

A fluid-tight and thermally insulating tank for the transport by sea of liquefied gases, partic. liquefied natural gases having a high methane content, incorporates two successive fluid-tightness barriers. One, the primary barrier, is in contact with the product contained in the tank. The other, the secondary barrier is disposed between the primary barrier and the bearing structure of the ship. These two fluid-tightness barriers are alternated with two thermally insulating barriers. The secondary insulating barrier is constituted of a cellular material fixed against the structure of the ship. The primary insulating barrier is held elastically against the secondary fluid-tightness barrier. The primary and secondary fluid-thighness barriers are constituted by metal plates welded edge to edge by their raised edges being welded to the two faces of a welding flange. The primary insulating barrier is constituted of rigid sheets realised e.g. in wood between which the welding flanges pass. The cellular material of the secondary insulating barrier carriers grooves in which bands are inserted allowing the fixation of the welding flanges perpendicular to the plane of the cellular material.