Ventilation of starting rotation device ventilation pipe is from Axial flow of swirl hole inner surface takes air leads to vacuum cavity, model existence of scale effect.
The young man, lost in the dark ventilation pipe, is trapped in a desperate world and lives in a dark night without daylight. Is there a lamp to navigate for you? Can you brush the shadows on your shadow?
But even if it is a ventilation pipe is also divided into several, there is a simple dust, smoke, exhaust pipe, but also have a special rule out harmful gas pipeline.