Inustrial fans and blowers are valuable tools for moving air and materials required in a wide variety of manufacturing processes and industries, including cement, power, mining, coal treatment, pollution control, oil and gas, ethanol and steel. Ranging in size from just a couple of feet to 12 feet in diameter, fans are categorized into one of four types: centrifugal, axial, high temperature, or mixed flow. They are used for a myriad of applications, including to supply combustion air for burners, to move dirty air streams, remove particulates from exhaust streams, ventilate mine shafts, blow coal dust into power plant furnaces, recirculate process gases, or induce drafts in kilns used to manufacture cement and other materials. Due to the extreme environments in which they are often used, these fans are frequently subject to corrosive chemicals, high temperatures and abrasive air streams. Therefore, for reliable service they must be carefully engineered. The latest computer modeling technologies, such as finite element analysis and computational fluid dynamics, are often employed in the design process, in addition to laboratory model testing.