With three layer co-extrusion technology, advanced technique batch formula, co-extrusion die having spiral channel and rotating core at a uniform motion, the line may be used to produce core foamed pipe, PVC inner spiral core foam pipe and hollow wall inner spiral muffle draining pipe. This pipe has smaller specific gravity, about 0. 92~1. 0g / cm3 (fornon foamed PVC pipe, it is 1. 4g / cm3) ,
Good sound isolation effect. As water dropping along the inner spiral of pipe, therefore reducing noise. It is identified by specialists that PVC inner spiral foamed pipe will decrease noise 5~7 db than core foam pipe, decrease noise 7~15db than solid wall PVC rigid pipe, and hollow wall inner spiral muffle draining pipe decrease noise 20~30 db than solid wall PVC pipe.