Francis fan 1. Introduction SWF series mixed flow fans is the company developed its own, with domestic and international advanced level of a new generation of fans, whose main characteristic is the flow coefficient greater than the centrifugal fan, total pressure coefficient is higher than axial fans , smaller than centrifugal fans, the company produced mixed flow fans divided in two fiberglass materials and steel, steel for general ventilation and exhaust fans. 2. Widely used in industrial and mining enterprises, hotels, restaurant, museums, stadiums and other places ventilation, suitable for pipe pressurized air supply and exhaust ventilation and high-rise buildings. 3, the structural characteristics: 1) high-efficiency, high zone width: This fan uses advanced CAD software and the performance by the multi-objective optimization design and development of high-tech products indicates that the application oblique meridional flow acceleration method (also called mixed flow fan) pressure compared with the same machine number of high axial fans, air volume compared with the same machine number large centrifugal fan with high efficiency, high efficiency zone width and other characteristics. 2) compact, easy to install, reliable operation: The fan in the case of the same amount of wind, air pressure, the average ratio of axial or centrifugal size should be small, can be installed directly or vertical installation and duct connection, horizontal, also on the wall or stand mounted directly, while using Direct motor method, with the installation, operation, easy to use features. 3) Low noise: the fan volute is specially designed to greatly reduce the cochlear flow noise. Under the unit amount of wind, air pressure unit working conditions, than A sound level can be reduced 2-3dB (A), while in the case of low speed, get a higher fan pressure. In the mining industry, and senior civil ventilation system can replace the low-pressure centrifugal fan or replace the high-pressure axial fan silencer without using a large number of measures. Wide range of applications: This series of products at single-speed and two-speed two models can be based on different occasions, to change the angle of the wind turbine installation, change the number of leaves and conversion speed reaches its requirements. 4, the structure and composition: ① shell: high quality low-carbon steel (A3) roll welding. ② Impeller: high quality carbon steel blades after stamping and molding wheel coupling, impeller after rigorous static and dynamic balance correction and motor assembly. ③ Motor: Y series three-phase asynchronous motors, with small size, light weight, reliable operation, rugged, reliable, and low noise, the quality of products.