The old technology and equipment in the curve of columnar,plane and cambered coiled pipes for circular pipe-coiled pipes and half pipe-coiled pipes were very complicated.

• 原有的圆管盘管和半管盘管中的柱面螺旋盘管、平面盘管和曲面盘管的结构繁杂、弯制质量差以及弯制工艺工装造价昂贵。