Forward Curved Vs Backward Curved Centrifugal Fan

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Forward curved vs backward curved centrifugal fan.

How does backward curved centrifugal fan work. The modern forward curved blades are designed with a scroll housing. The forward curved is parallel to the edge. A backward curved centrifugal fan is characterised by its cylindrical shape several large curved blades and a conical inlet nozzle.

Backward inclined the performance of the backward inclined wheel is similar to the forward curve however bi fans tend to be non overloading meaning their fan curves do not tend to increase hp as static pressure changes but cfm falls off. The centrifugal fans with forward curved blades 2l 90 o are designed due to the small dimensions and good static pressure characteristics of fans and such a recommendation refers to the fans. Flatter pressure curve and lower efficiency than the airfoil fan backward curved fan and backward inclined fan. The difference is the length of impeller rail and the edge.

2 forward curved blades provide a low noise level comparitive to backward curved blades because backward curved blades have high speed relatively to forward curved blades for same capacity range. 1 forward curved blades curve in the direction of the fan wheel s rotation on the other hand backward curved blades curve against the direction of the fan wheel s rotation. In most cases these fans are designed with external motors. Backward curved these wheels are extremely efficient more robustly built and very quiet.

Motor selection must take this into account. The name centrifugal fan is derived from the direction of flow and how the air exits the fan impeller radially from the outer circumference of the fan. Backward curved centrifugal fans. Forward curved centrifugal fans are more cost effective than backward curved centrifugal fans though and have become popular in industries like the medicinal industries since they don t accumulate chemicals and other debris on their blades.

The difference in flow direction between a forward and backward curved centrifugal fan is the direction that the air exits the impeller circumference. With a backward curved impeller the air exits in a radial direction whereas with a forward curved the air exits tangentially from the circumference of the fan. Pressure curve less steep than that of backward curved fans. Another important design feature is the position of the motor.

The forward curved type is generally are blowers and the backward curved type are induced draft fans. This reduces the level of noise.