MANUFACTURE OF DOUBLE FLAT PIPE

摘要

PROBLEM TO BE SOLVED: To provide the manufacturing method of a double flat pipe, which can efficiently make the double flat pipe high in strength with little deformation in a simple manufacturing processes. SOLUTION: A flat elastic belt body 2 in a fusion condition is wound in a spiral shape over the outer circumference of a mandrel in such a way that its end peripheries are overlapped so as to be formed into a flat inner pipe part P1 , a plastic belt shaped molded body 3 having each flat part 3b, and each trough part 3a in a fusion condition, is wound over the outer circumference of the aforesaid inner pipe part P1 in a spiral shape in such a way that each trough part 3a is covered by each flat part 3b, and an intermediate corrugate pipe part P2 is integrally formed with a flat outer pipe part P3 , so that a double flat pipe P is thereby manufactured.