Flexible End Cap 

HDPE Butt Fusion End Cap. The working principle of the siphon drainage system depends on the special designof the rainwater hopper implement separation, So that the rain is flowing state in theriser, when the rain reached a certain capacity in the riser, siphonage is generated.In the process of rainfall, due to the continuous siphonage, the whole system is able toquickly rule out water from the roof. Butt Fusion Welding and Electrofusion Welding.