Howden Standard/configured fans Mixed Flow Fans

Mixed Flow Fans The mixed flow (or axial impulse) fan is a cost-effective alternative to an axial flow fan in situations where capital cost and resistance to erosion are as important as power consumption. Key benefits A mixed flow fan combines the features of an axial and a centrifugal fan, although the impeller looks more like fixed bladed axial type. Efficiency can match other types of fan, within its optimum operating envelope. Impeller design is robust and the plate blades are ideal for handling dust laden gases at elevated temperatures. Fan performance is less degraded by erosion or corrosion, and the blades are easily weld repaired. Standard features The impeller consists of curved steel plate blades, which are welded to a conical hub. This simple robust impeller is ideal for handling dust-laden gases at elevated temperatures. Impulse bladed mixed flow fans are controlled by inlet radial vane controls similar to those used with centrifugal fans. This form of control is extremely effective, and allows rapid changes in fan output in response to process demands. The inherently low velocities within the impeller result in low wear rates in dusty environments. As the aerodynamic performance of the fan is not sensitive to wear on the blade profile, the fan output is not noticeably degraded by erosion or corrosion, and the fan will maintain high operational efficiencies over a long period of time without the need to replace the blades. Optional features If required, the fan can be supplied with a passive stabilizing chamber which modifies the fan performance characteristic, and eliminates the stall characteristic. The aerodynamic design of the stabilizing chamber can be adjusted to allow the available pressure at low flow to be controlled to suit specific process requirements.