Tank and manufacturing method for tank

1. A manufacturing method for manufacturing a tank, comprising:

a step of forming a structural body comprising a liner and a fiber reinforced resin layer placed on an outer periphery of the liner, the structural body including:

a cylindrical portion,

dome portions provided at opposite ends of the cylindrical portion in an axial direction of the cylindrical portion,

a mouth piece, and

a fusible plug valve attached to the mouth piece, the mouth piece and the fusible plug valve being provided in one of the dome portions;

a step of winding a heat insulating sheet around the fiber reinforced resin layer after the step of forming the structural body, the heat insulating sheet having notches in dome forming portions provided to correspond to the dome portions; and

a step of covering the dome portions with the dome forming portions of the heat insulating sheet, wherein a number of layers of the heat insulating sheet in one of the dome forming portions is smaller than a number of layers of the heat insulating sheet in an other of the dome forming portions.

2. The manufacturing method according to claim 1 , wherein:

the heat insulating sheet includes adhesive layers or adhesive agents on opposite surfaces of the dome forming portions;

the heat insulating sheet includes an adhesive layer or an adhesive agent on one surface of a region between the dome forming portions; and

after the step of winding the heat insulating sheet, the adhesive layers or the adhesive agents provided in the dome forming portions corresponding to the dome portions are exposed, and tank protectors are attached to the dome forming portions.

3. The manufacturing method according to claim 1 , wherein the number of layers of the heat insulating sheet in the one of the dome forming portions is one, and the number of layers of the heat insulating sheet in the other of the dome forming portions is two.

4. A tank comprising:

a structural body constituted by a liner and a fiber reinforced resin layer formed on an outer periphery of the liner, the structural body including:

a cylindrical portion,

dome portions provided at opposite ends of the cylindrical portion in an axial direction of the cylindrical portion,

a mouth piece, and

a fusible plug valve attached to the mouth piece, the mouth piece and the fusible plug valve being provided in one of the dome portions; and

a heat insulating layer placed on an outer side of the structural body, the heat insulating layer being formed by use of a heat insulating sheet, wherein the heat insulating sheet includes

dome forming portions covering the dome portions, the dome forming portions having notches, wherein a number of layers of the heat insulating sheet in one of the dome forming portions is smaller than a number of layers of the heat insulating sheet in an other of the dome forming portions, and

an intermediate portion provided as a region between the dome forming portions such that the intermediate portion is wound around the cylindrical portion of the structural body in a circumferential direction of the cylindrical portion.

5. The tank according to claim 4 , comprising tank protectors provided on outer sides of the dome portions.

6. The tank according to claim 4 , wherein the number of layers of the heat insulating sheet in the one of the dome forming portions is one, and the number of layers of the heat insulating sheet in the other of the dome forming portions is two.