"Axial Fan" blower pipe system refers to a fan unit of all piping and accessories in addition to the fan, a suction device, the sum of the discharge apparatus. Pipe fan performance curve is the total energy per unit volume of the gas from the suction space via line and accessories to the press room for the required cp (ie, total pressure) and delivery pipeline system flow rate Q of the curve. Usually suction space and room for both atmospheric pressure and the gas potential energy is usually ignored, the mathematical expression of the line performance curve is Pc = SpQ² (N / m).