"Exhaust Fan" ventilation methods are discharge type, inhaled, and with three. Discharged into the formula from the natural gas inlet air, dirty air is discharged through the this fan; inhaled through the ventilation fans inhale fresh air, dirty air exhaust vent from nature; and the formula is by suction and exhaust ventilation fans to complete. Low investment costs "Exhaust Fan" has a large air volume, low noise, low energy consumption, stable operation, long life and high efficiency. Blinds can automatically shuts so as to achieve the dust, waterproof effect, elegant, modern plant cooling ventilation is the best choice. Environmentally friendly, energy-saving features of the "Exhaust Fan" will become the ventilation and cooling equipment market mainstream.