"Exhaust Fan" outwardly discharge air in the process will cause indoor air pressure drops, indoor air becomes thin, the formation of a negative pressure zone, due to the pressure difference between the air flows into the indoor compensation. In practical applications, industrial plants, the fan is usually installed in the plant are concentrated on one side, the air inlet in the plant room on the other side, the air from the intake port to "Exhaust Fan" convection hair. In this process, the fan near the doors and windows remain closed, forcing air to flow into the inlet side of the shop windows compensation. Air lined up orderly by the air intake flow into the plant, from the plant flows from the "Exhaust Fan" discharge workshop. Ventilation thorough, efficient, and ventilation rate can be as high as 99%. Through specific engineering design, according to need to design ventilation speed and wind speed, any fever, harmful gases, dust, smoke can quickly discharged workshop, any poor ventilation problem could resolve once and for all. Turn the fan from a few seconds to reach the effect of ventilation.