Hollow member, manufacturing method therof, fluid distribution system using the hollow member, and forming apparatus of hollow member

A forming apparatus for forming a hollow material (W, W′) for a container by disposing individual material plates (W1, W2, W3, W4, W5) that are different in plate thickness or material between electrodes, joining the material plates (W1, W2, W3, W4, W5) mutually by mush seam welding to form a plate member (W0, W0′) that is partially different in plate thickness or material, bending the plate member (W0, W0′), disposing mutually opposing axial sides of the plate member (W0, W0′) between electrodes (21, 23), and joining the mutually opposing axial sides of the plate member (W0, W0′) together by mush seam welding, characterized by comprising:

• flat plate holding means (24) for holding individual material plates (W1, W2, W3, W4, W5) that are different in plate thickness or material so as to join the material plates (W1, W2, W3, W4, W5) by mush seam welding;
• bend forming means (25) for bending the joined plate member (W0, W0′);
• bent plate holding means (26) for holding the mutually opposing axial sides of the bent plate member (W0, W0′) so as to join the bent plate member (W0, W0′) by mush seam welding;
• a first electrode (22), being one electrode for mush seam welding provided in the flat plate holding means (24);
• a second electrode (23), being one electrode for mush seam welding provided in the bent plate holding means (26);
• a third electrode (21), being another common electrode for mush seam welding in collaboration with both the first and second electrodes (22, 23), respectively;
• and
• mush seam welding direction moving means (27) for moving the flat plate holding means (24) holding the plate member (W0, W0′) and the bent plate holding means (26) relatively close to and away from the other electrode (21) in the mush seam welding direction.