| 摘要 |
PROBLEM TO BE SOLVED: To provide a double-layered piping material capable of making simple and small a component (or joint) to be separately used in a connection portion of a pipe.SOLUTION: A flange portion 3 is formed: by enlarging a diameter of an existing pipe, which has a metal layer a, inner layers b made of a thermoplastic resin and disposed on an inner side of the metal layer a, and outer layers made of a thermoplastic resin and disposed on an outer side of the metal layer a, to form an enlarged diameter portion to become a socket portion 2; by bending a leading end portion of the diametrically enlarged portion once outward; and by folding the diametrically enlarged portion into halves in a direction for the inner layers b to abut against each other. |
