A pressure vessel includes a vessel body including a cylindrical-shaped straight body portion with a spiral-shaped projection portion formed at an outer peripheral surface of the straight body portion, and a covering portion that comprises a fiber bundle wrapped onto the outer peripheral surface of the straight body portion in a spiral pattern running parallel to the projection portion so as to cover the outer peripheral surface of the straight body portion.

A pressure vessel includes a vessel body including a cylindrical-shaped straight body portion with a spiral-shaped projection portion formed at an outer peripheral surface of the straight body portion, and a covering portion that comprises a fiber bundle wrapped onto the outer peripheral surface of the straight body portion in a spiral pattern running parallel to the projection portion so as to cover the outer peripheral surface of the straight body portion.

A helical winding unit of a filament winding apparatus includes guide members guiding fiber bundles F to a liner, a movement mechanism moving the guide members, and a rotation mechanism rotating the guide members. Each of the guide members includes two side walls and guide portions fixed between the two side walls. As the guide portions, a first guide portion having a first guide surface and a second guide portion having a second guide surface and provided downstream of the first guide portion are provided. In the height direction, the first guide surface is oriented to one side. The second guide surface is oriented to the other side in the height direction and provided on the other side of the first guide surface.

A helical winding unit of a filament winding apparatus includes guide members guiding fiber bundles F to a liner, a movement mechanism moving the guide members, and a rotation mechanism rotating the guide members. Each of the guide members includes two side walls and guide portions fixed between the two side walls. As the guide portions, a first guide portion having a first guide surface and a second guide portion having a second guide surface and provided downstream of the first guide portion are provided. In the height direction, the first guide surface is oriented to one side. The second guide surface is oriented to the other side in the height direction and provided on the other side of the first guide surface.

Multilayer structure for transporting hydrogen, including, from the inside, at least one sealing layer and at least one composite reinforcing layer, an innermost composite reinforcing layer being wound around an outermost adjacent sealing layer, the sealing layers of a composition predominantly of at least one semi-crystalline, long-chain polyamide thermoplastic polymer P1i (i=1 to n, n being the number of sealing layers), the Tf of which, as measured according to ISO 11357-3: 2013, is greater than 160° C., with the exception of one polyether block amide (PEBA), up to 50% by weight of impact modifier relative to the total weight of the composition and up to 1.5% by weight of plasticiser relative to the total weight of the composition, the composition being free of nucleating agent, and at least one of the composite reinforcing layers being of a fibrous material.

A multilayer structure for transporting hydrogen, including, from the inside, a sealing layer and at least one composite reinforcement layer, an innermost composite reinforcement layer being wound around the sealing layer, the sealing layer being a composition predominantly of: a polyamide thermoplastic polymer PA11, up to less than 15% by weight of impact modifier, up to 1.5% by weight of plasticizer relative to the total weight of the composition, the composition being devoid of nucleating agent and of polyether block amide (PEBA), and at least one of the composite reinforcement layers being a fibrous material in the form of continuous fibers, which is impregnated with a composition predominantly of at least one polymer P2j, (j=1 to m, m being the number of reinforcement layers), the structure being devoid of an outermost layer and adjacent to the outermost layer of a composite reinforcement layer made of a polyamide polymer.

A step of forming a low-angle helical layer on an outer surface of at least part of each liner dome portion and an outer surface of a liner cylindrical portion, a step of forming an inner hoop layer on an outer surface of the low-angle helical layer on the liner cylindrical portion, and a step of forming a mixed layer by alternately laminating a low-angle helical layer and an outer hoop layer on an outer surface of the inner hoop layer and low-angle helical layer on each liner dome portion. Then, on the liner cylindrical portion, 90% or more of the sum of the thickness of the inner hoop layer and the thickness of the outer hoop layer in the mixed layer is arranged within the range of 75% of the fiber reinforced plastics layer adjacent to the liner in a thickness direction of the fiber reinforced plastics layer.

A liner includes dome sections having outer surfaces along an uniform stress surface at both ends in an axial direction, and nozzles are mounted on the dome section by introducing nozzle flanges into pedestal sections of apexes of the dome sections. Then, ring-shaped caps having the same linear expansion coefficient as the liner and inner surfaces in a curved surface shape of outer surfaces of the dome sections and the nozzle flanges are mounted on boundary portions between the nozzle flanges and the pedestal sections. In forming a fiber layer after that, a helical winding layer is formed first by winding a fiber bundle disposed at the dome sections to cover the dome sections while including the nozzle flanges.

A liner includes dome sections having outer surfaces along an uniform stress surface at both ends in an axial direction, and nozzles are mounted on the dome section by introducing nozzle flanges into pedestal sections of apexes of the dome sections. Then, ring-shaped caps having the same linear expansion coefficient as the liner and inner surfaces in a curved surface shape of outer surfaces of the dome sections and the nozzle flanges are mounted on boundary portions between the nozzle flanges and the pedestal sections. In forming a fiber layer after that, a helical winding layer is formed first by winding a fiber bundle disposed at the dome sections to cover the dome sections while including the nozzle flanges.

A manufacturing method of a tank comprises winding a fiber on a liner by hoop winding. The winding comprises: forming an (N+1)-th layer such that a position closer to a center of the liner by a first predetermined distance along an axis line direction of the liner from an end in the axis line direction of an N-th layer is set to position of an end in the axis line direction of the (N+1)-th layer with respect to a direction perpendicular to the axis line direction; and winding the fiber on the N-th layer to provide one winding turn of the fiber, such that a pressing force of pressing the N-th layer in the axis line direction by the fiber is equal to or smaller than a total frictional force in an area in the N-th layer on an edge side in the axis line direction of a fiber winding position.