Three Types of Impeller Designs for Cabinet-Type Centrifugal Fans
Generally speaking, the internal impeller design of cabinet-type centrifugal fans may vary depending on the specific application.
Currently, there are three commonly used impeller designs: forward-curved blades, backward-curved blades, and radial blades.
So, what are the characteristics of these three different structural types?
Let’s analyze this aspect. First, let’s examine the characteristics of centrifugal fan cabinets with forward-curved blades.
Relatively speaking, this type of machine operates at a slower speed. Currently, this type of unit is primarily used under operating conditions with high airflow and low static pressure.
The main advantages of this unit are low cost, low speed, a slender shaft, smaller bearings, and a wide operating range.
The second impeller configuration is known as the backward-curved blade. Compared to the former, this type of machine operates at a higher speed—approximately twice as fast.
Consequently, under given operating conditions, this type of centrifugal fan cabinet achieves higher efficiency, and its performance is notably superior.
The main advantages of this unit are its high operational efficiency and the absence of overload on the power curve. In other words, overload issues rarely occur during normal operation.
However, the disadvantages are also evident. Due to the high rotational speed of the impeller, a thicker shaft and larger bearings are required.
At the same time, there are high demands on balancing. Furthermore, this type of centrifugal fan cabinet unit is susceptible to fluctuations in static pressure.
One design is known as the radial blade. The term "radial blade" essentially indicates that its structure lies somewhere between the two types described above.
This cabinet-type centrifugal fan offers excellent strength and wear resistance. Typically, the blade’s exit angle is 90°.
