... duct for ventilation purpose, diameter from 80-1500mm. The spiral duct forming machine ZHTF-1500I is used to produce the round rigid air ... hydraulic station: 8kgf/cm2Key words: spiral tubeformer, spiral duct forming machine, ventilationd duct machine, spiral tube former, spiral duct former, ventilationd duct machine, HVAC duct machine, air duct machine. Spiral duct forming machine