​What are the differences in function and structure between stainless steel centrifugal fans?

What are the differences in function and structure between stainless steel centrifugal fans?

During operation, stainless steel centrifugal fans convert kinetic energy into potential energy. The high-speed rotating impeller accelerates the gas, then decelerates it while changing its flow direction, thereby converting kinetic energy into potential energy (pressure). In single-stage stainless steel centrifugal fans, gas enters the impeller axially, transitions to radial flow through the impeller, and then enters the diffuser. Within the diffuser, the gas changes direction, the duct cross-sectional area increases, and the gas flow slows down, thereby converting kinetic energy into pressure energy. The primary pressure increase occurs in the impeller, after which the diffusion process continues. In multi-stage stainless steel centrifugal fans, a counterflow device directs air into the next impeller to achieve higher pressures. The mechanism of stainless steel centrifugal fans is fundamentally similar to that of turbo compressors. However, due to lower gas flow rates and smaller pressure changes, the gas specific volume (i.e., gas behavior) need not be considered. They are treated as incompressible fluids. Stainless steel centrifugal fans can be manufactured for right-handed or left-handed operation. From the motor side: - Propeller rotates clockwise: This is termed a right-handed fan. - Propeller rotates counterclockwise: This is termed a left-handed fan. Construction of Stainless Steel Centrifugal Fans Stainless steel centrifugal fans consist of a casing, main shaft, impeller, bearing transmission mechanism, and motor. Housing: Constructed from steel plate for robustness and reliability. Available in integral and semi-open types; the semi-open design facilitates maintenance. Impeller: Composed of blades, an arc-shaped front plate, and a flat rear plate. Rotor: Achieves static and dynamic balance to ensure smooth rotation and superior performance. Drive Assembly: Consists of the main shaft, bearing housing, rolling bearings, and belt pulley (or coupling). Performance Characteristics of Stainless Steel Centrifugal Fans Centrifugal fans are inherently variable-flow, constant-pressure devices. At constant speed, their theoretical pressure-flow curve is linear; actual curves deviate due to internal losses. The pressure generated by stainless steel centrifugal fans is significantly affected by changes in inlet air temperature and density. For a specific inlet air condition, pressure decreases with lower air temperature (lower air density). For a given pressure-flow characteristic curve, there exists a corresponding power-flow characteristic curve. When operating at a fixed speed, the power requirement increases as the inlet air temperature decreases relative to the specified flow rate.