ventilation, fans, aspirators, air handling units, AHU, Please take offer for your projects. ,The fans, which are called by various names according to their working principle, are preferred according to the program required by the closed areas. According to this; There are definitions such as aspirator, fan, bellows and blower. Air suction fans used in ventilation systems are beneficial in excluding bad air layers. Pressure ventilators are used to prevent air layers from spreading to closed spaces due to environmental effects. Before moving on to the fan types, it is necessary to pay attention to some points to be considered in the choice of these mechanisms.