NCCER Millwright Practice Exam

The type of centrifugal fan that is suitable for equipment with long shafts is the _______ type

1. Backward-curved

2. Foward-curved

3. Radial

4. Axial

The correct answer is: Foward-curved

The most suitable type of centrifugal fan for equipment with long shafts is the forward-curved type. Forward-curved fans are designed with blades that curve in the same direction as the rotation of the impeller, which allows for a higher volume of air movement at lower pressure levels than other designs. This design minimizes the loading on the bearings and allows for smooth airflow, making it particularly beneficial for applications where long shafts might introduce additional challenges such as vibration or imbalance. These factors contribute to the reliability and efficiency of the fan in systems where long distances need to be covered, which is common in industries where space constraints are present or where extensive ducting systems are required. In contrast, other types of fans, while functioning well in various scenarios, may not perform as optimally in the specific context of long shafts. For instance, backward-curved fans, though efficient at handling high pressures, can produce significant torque and may not manage the dynamics of long shaft setups as effectively as forward-curved fans. Radial fans could introduce more bearing loads due to their operational characteristics, and axial fans typically move air more directly but are less efficient in situations requiring extensive ductwork. Thus, the forward-curved fan is the optimum choice in this scenario.