When the sending and exhausting shaft is ventilated, short duct flow may occurred between outlet and inlet, which will baffle air exchange in highway tunnel.
在竖井送排式通风时，排风口和送风口之间可能产生短道流动，这种短道流动会阻碍隧道内的空气交换。
2
Attaching it to the shaft of propeller with rotary duct will lead to a better result.
若在转动导管螺旋桨上加装PBCF，其效果更佳。
3
Equipped with a ladder into the air shaft, the drainage pipes, duct pressure, fire sprinkler pipe and power cables for safety into the ventilation shaft and exports;