| 摘要 |
<p>PURPOSE: To increase a flattening pressure resistance strength by bonding a metal plate covered with synthetic resin along the inner periphery surface of the spiral ridge of a corrugated pipe of hard synthetic resin. CONSTITUTION: In a pipe wall 1 of a corrugated synthetic resin pipe formed in cylindrical shape, a recessed and projecting wall in spiral shape alternately with a ridge 2 and a bottom part 3 is formed. A flat metal plate 4 whose entire- periphery surface is covered with synthetic resin (preferably, the same material as the synthetic resin material for forming the pipe wall) is spirally wound on the inner-periphery surface of the ridge 2 of the pipe wall and is bonded to the pipe wall 1, thus increasing the coating thickness of the ridge 2 and extremely improving the pressure resistance strength against external force.</p> |
