The shell of FRP horn type negative pressure fan is made of composite glass steel, and both motor and fan blade are made of high quality aluminum alloy. This series of fans use the principle of negative pressure design. Themuggy and high temperature gas around the fan is quickly drained. The effect of axial flow fan shaft pumping in effective area. This series of fans have the advantages of light weight, smooth operation, low mechanical noise, easy aging, good corrosion resistance, easy installation and so on. The design of blinds on the back of the fan is designed to make use of the principle of air flow. The blinds can be opened and closed independently according to the operating state of the fan.