Siphon storm system and siphane drain member

摘要

To provide an elbow for allowing rain water to flow down smoothly.SOLUTION: An elbow 114 according to the invention is an elbow arranged at downstream side of a siphon rain gutter system equipped with eaves gutter and a siphon generation part having a cylindrical part for penetrating into a water collection port formed on a bottom surface of the eaves gutter and configured for generating a siphon phenomenon, the elbow comprises a bent pipe part and a receptacle provided at both ends of the bent pipe part, and in the bent pipe part seen in a cross section in a plane including a tube axis of the bent pipe part a radius of curvature of an internal wall surface of an inner peripheral side is greater than 64 mm and smaller than 100 mm.SELECTED DRAWING: Figure 4