... 1,vibrating sieve, 2,high speed mixer machine 3,cooling machine,4, plastic powder charger,5, conical double-screw extruder, 6,hadpiece, 7 ... ,double wall accordion pipe shaper,8, plastic pipe-expanding machine, 9,pilling bin ... chilling unit, 11,air compressing machine. It can be used to produce PVC PE plastic double-wall accordion pipes and plastic ...