downward ventilation system 从底板排出的通风系统
downward system of ventilation 下向通风系统
downward d ventilation 下向通风
downward displacement ventilation 传统置换通风
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The stope downward ventilation technique has been used under different conditions in many places of our country.
回采工作面下行通风在我国许多地方的不同条件下均有使用。
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However, when the fire happens, the downward ventilation can often cause the air disorder and air inversion easily.
但下行通风在发生火灾时往往会引起风流紊乱，容易造成风流逆转。
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