Spiral hollow wall winding tank making machine Diameter range: 2000-4000mm; Ring stiffness: SN4/SN8 Machine Constitute: 1,Single Screw Extruder 2,Die&Mould 3,Vacuum Calibration Tank 4,Cooling tank 5,Haul-off machine 6,Forming Machine 7,Cutting Machine 8,Stacker