ZHANGHUANG blower features: spiral shape is 20. Or more fixed helical fashion. Into the exhaust shield casing spiral cut, smooth the top line of a triangular configuration of the rotor into the exhaust port, through the rotation of the rotor and sequentially opened. The fan inlet and outlet, unlike the old spiral Roots blower as open or closed at the moment, so the sound operation minimal, almost no exhaust pulsation. Because the rotor is the clover linear, so it is not like a spiral rotor, as a result of the axial displacement of the rotor slight contact with each other. Therefore, only to ensure that the gap between the rotor profile, do not like the way plus spiral rotor axial displacement, so that the gap is too big. This fan efficiency than the same size rotor helical fan better. Due to take special shape of the rotor, the rotor is easy to keep a gap between each other, so that efficiency is further improved. The use of precision CNC machine tools production rotor, and the accuracy of management has taken measures to improve, so there is no error between the performance of wind turbines. Further, the rotor has become an equilibrium state in the manufacturing process. Therefore, the rotor will not be as in the past the tiny residual imbalance. The machine is almost no vibration. Using the most advanced drive gear, so unfair life has been extended, and to achieve a low noise. The gears are made of special Cr-, Mo steel hardened properly, in strict accordance with JISI stage gear manufacturing precision grinding. Thus from gear harmful interference to the product completely ruled out. Output clean air, free of any oily dirt. Inside the enclosure do not need oil lubrication, and avoid using a bearing, gear oil mixed with the internal structure of the chassis design.