500 turbo exhaust fan installed in the forces of nature on the roof of the factory can be achieved very good results, because the plant often due to the operation of machine tools generate heat and smoke pollution, according to "thermal expansion and contraction," the principle of thermal expansion of air So the number of air molecules within a certain volume of fewer, relative density of hot air than cold air will be small, the hot air is lighter than colder, therefore, indoor hot air to rise, the cold air going down, so the heat or indoor smoke pollution will be gathered in the vicinity of the roof, so the indoor temperature is high, pressure, and with the rotation of the turbine on the roof and the diversion law, so the heat or indoor smoke pollution from the leaves of the gap will spin out of the room, when the hot air out after Interior will have low pressure, while the outdoor air at high pressure outside, so air will flow into the indoor, the heat is pumped to fill the space, and then to adjust the temperature, to the effect of decontamination smoke, so that clean indoor air becomes cool,