The whole machine adopts CAD/CAM design, with low investment cost, high air volume, low noise, low energy consumption, stable operation, long service life and other characteristics, shutters automatically closed dustproof, waterproof, beautiful and generous, can be used as hair dryer, also can be used for ventilation, is the choice of modern workshop cooling and ventilation. Environmental protection and energy saving negative pressure fan will become the mainstream ventilation and cooling equipment.