?回风管

... return condensate 冷凝回水 return duct 回风管 return flow 回流 ...

?回流管

...回流管 backflow connection; bypass line trip; crossover; recirculatory pipe; reflux pipe; return conduit; return duct; return line; return pipe; return tube; runback 回流罐 reflux accumulator; reflux drum; return tank .

?回收空气管道

... Return Register（回收空气调节器）； Return Duct（回收空气管道） AIR CONDITIONER（空调）； ...