| 摘要 |
PURPOSE:To provide lightweight and highly rigid composite pipe as distributing water pipe or the like embedded in the ground and its manufacturing method without impairing its executability. CONSTITUTION:Lightweight and highly rigid composite pipe is obtained by forming a continuous spiral projecting bead on the inner surface of metal pipe and a projecting bead, which crosses said spiral projecting bead on the inner surface through the wall of the pipe by the predetermined angle, on the outer surface of the pipe and by covering its inner surface with resin. By spirally winding metal band plate, on one side of which continuous projecting bead is formed and, at the same time, on the other side of which projecting beads intersecting said continuous projecting bead by the predetermined angle is formed, and joining the abutting parts of the band plate, the metal pipe is produced. At the same time, by extruding molten resin in the resultant pipe so as to cover the inner surface of the pipe, the composite pipe having the above-mentioned structure can easily and continuously be manufactured. |
