Flow Control
There are several means of controlling the flow rate of a fan, e.g., temporarily reducing the air or gas flow rate; these can be applied to both centrifugal and axial fans.
Speed Variation - All of the fan types described above can be used in conjunction with a variable speed driver. This might be an adjustable frequency AC controller, a DC motor and drive, a steam turbine driver, or a hydraulic variable speed drive unit ("fluid drive"). Flow control by means of variable speed is typically smoother and more efficient than by means of damper control. Significant power savings (with reduced cost of operation) are possible if variable speed fan drives are used for applications that require reduced flow operation for a significant portion of the system operating life.
Industrial Dampers - These devices also allow fan volumetric flow control during operation, by means of panels so as to direct gas flow or restrict the inlet or outlet areas.
There is a variety of types of dampers available:
Louvered Inlet Box Dampers
Radial Inlet Dampers
Variable Inlet Vane (VIV) Dampers
Vortex Dampers
Discharge Dampers
Read more about this topic: Industrial Fans
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