玻纤风管
the fine tuber pipe of glass
薄钢板焊接风管
the steel sheet welds the wind duct
长距离曲线顶管风险
long-distance curved pipe-jacking risk
超级风管特点
characteristic of super ventilation duct
超宽大截面风管
super-wide large section air duct
承压风管漏风量
pressurized duct air-leakage
大口径双层螺旋保温风管
large diameter two-layer spiral insulating air duc