Fluid handling device for liquid hydrogen

A fluid handling device for liquid hydrogen, comprising:

• a swivel joint section rotatably connected to piping sections including an inboard arm, an outboard arm, and elbow piping, the piping sections having a vacuum dual pipe structure;
• wherein the swivel joint section further comprises:
• an outer ring that is connected with one of the piping sections, the outer ring being exposed to an ambient atmosphere,
• an inner ring that is connected with another of the piping sections, the outer ring and the inner ring being engaged with and rotatable with respect to each other, the inner ring having an interior passage being configured to be in contact with and permit a flow of the liquid hydrogen,
• a bearing disposed between the outer ring and the inner ring,
• a boundary relative-rotation section storing helium gas that is disposed between the outer ring and the inner ring, wherein a state is induced in which a local pressure within said boundary relative-rotation section is higher than a pressure of the ambient atmosphere, and
• a purge port disposed on the outer ring that is configured to permit the helium gas to be injected into the boundary relative-rotation section from outside of the fluid handling device,
• wherein the outer ring comprises a first outer section and a first inner section, with a first vacuum section disposed between the first outer section and the first inner section,
• wherein the inner ring comprises a second outer section and a second inner section, with a second vacuum section disposed between the second outer section and the second inner section,
• wherein the boundary relative-rotation section is disposed between the first inner section and the second outer section,
• wherein the second outer section and the second inner section of the inner ring are mirror-finished, and
• wherein a stacked-layer vacuum heat insulation section in which radiation shield sheets and spacers are stacked is provided between the second outer section and the second inner section of the inner ring.