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。

youdao

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。

youdao

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;

进风立井装备梯子间、排水管、压风管、消防洒水管以及动力电缆等，为进风井兼安全出口；

youdao