Patent ID: 6378722
Filing Date: 2002-04-30
Classification: B65D,F17C

Abstract:
Watertight and thermally insulating tank built into a bearing structure (1), particularly of a ship, said bearing structure (1) having a number of substantially flat faces (2) adjacent via their longitudinal edges and having a polygonal cross section, each pair of longitudinally adjacent faces (2) forming a dihedron (4), said tank comprising two successive watertightness barriers, one of them a primary watertightness barrier (43, 65, 62) in contact with the product contained in the tank, and the other a secondary watertightness barrier (14, 55, 30, 40) arranged between said primary watertightness barrier and the bearing structure (1), a primary thermally insulating barrier (12,13,24,27,28,29,37,38,51,54,71) being arranged between these two watertightness barriers and a secondary thermally insulating barrier (15,16,57,58,31,32,41) being arranged between said secondary watertightness barrier and the bearing structure (1), the secondary insulating and watertightness barriers and the primary insulating barrier being essentially formed of a collection of wall elements (9,10,56) juxtaposed on the bearing structure (1) over substantially its entire interior surface (8), said wall elements (9,10,56) being partially deformable in the direction of their thickness, said wall elements (9,10,56) being capable of supporting and of retaining the primary watertightness barrier, said primary watertightness barrier having substantially flat running metal strakes (62) made of thin sheet metal with a low coefficient of expansion, the longitudinal edges (61) of which are turned up toward the inside of the tank, each running strake (62) being assembled watertightly with at least one longitudinally adjacent running strake (62), the adjacent turned-up edges (61) of said running strakes (62) being welded to the two faces of a weld support (60) which is mechanically held on said wall elements (9), characterized in that said primary watertightness barrier comprises, on each side of the longitudinal solid angle of intersection (A) of at least one of said dihedra (4), a longitudinal row of corrugated corner strakes (65), each corner strake (65) having a first longitudinal edge (67), opposite said solid angle of intersection (A) of the dihedron, which is turned up toward the inside of the tank and welded to one face of a weld support (64) held mechanically on said wall elements (56), the longitudinal edge of a running strake (62) longitudinally adjacent to said corner strake (65) being welded to the other face of said weld support (64), each corner strake (65) comprising at least one corrugation (66) between its two longitudinal edges (67,68) so as to be capable of deforming transversely to elastically follow any deformation there might be of said wall elements (9,10,56) supporting said primary watertightness barrier, it being possible for said deformation to be brought about by the static (F) or dynamic pressure of the product contained in said tank and/or the thermal contraction.