SYNTHETIC RESIN CORRUGATED PIPE HAVING A CONCAVE-CONVEX SURFACE

摘要

A SYNTHETIC RESIN CORRUGATED PIPE (P) INCLUDES A PIPE WALL (1) HAVING AN ANNULARLY- OR HELICALLY-SHAPED CONVEX-CONCAVE SURFACE. THE CONVEX-CONCAVE SURFACE HAS A PLURALITY OF CONVEX PORTIONS (2) HAVING A QUADRANGULAR CROSS-SECTIONAL SHAPE AND A PLURALITY OF CONCAVE PORTIONS (3) HAVING A CIRCULAR CROSS-SECTIONAL SHAPE.