To firmly join a spiral guide passage by previously embedding a heating wire in an outer peripheral edge part of the spiral guide passage or in the vicinity of mutually joining parts in a pipe main body part, and opposing the mutually joining parts of the outer peripheral edge part of the spiral guide passage and a main body part inner peripheral surface, and fusing the opposed parts by carrying an electric current to the heating wire.
An outside diameter of an outer peripheral edge part of a spiral guide passage 12 is set to a slightly smaller outside diametrical dimension having a clearance to be brought into contact in a spiral shape with an inner peripheral surface of a pipe main body part 11 or only to be filled up by expansion of resin at fusing time. A heating wire 121 is previously embedded over the whole circumference in the outer peripheral edge part of the spiral guide passage 12, and its end part is derived, and is formed as a terminal 121'. Next, the spiral guide passage 12 is inserted into the pipe main body part 11, and after the outer peripheral edge part of the spiral guide passage 12 is opposed to a part to be joined of an inner peripheral surface of the pipe main body part 11, an electric current is carried to the heating wire 121, and it is heated, and contact parts are fused on each other. Therefore, the spiral guide passage 12 can be firmly joined to the inner peripheral surface of the pipe main body part 11.
Nakagawa, Hirohide
Marushita, Yoshikazu
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