Tennessee Wastewater Operator Practice Exam

In centrifugal blowers, how is airflow and pressure created?

1. By a nozzle compressing air

2. By an impeller rotating and flinging air

3. By a fan pulling in ambient air

4. By constant speed rotation of the motor

The correct answer is: By an impeller rotating and flinging air

The correct answer highlights the mechanism by which centrifugal blowers generate airflow and pressure. Centrifugal blowers rely on an impeller, which is a rotating component that plays a critical role in the blower’s operation. As the impeller spins, it draws air into the blower and flings it outward due to centrifugal force. This action not only accelerates the air but also increases its pressure as it moves through the blower housing. The design of the impeller and the surrounding casing is such that it helps convert the kinetic energy gained from the spinning impeller into pressure energy, resulting in increased airflow at the outlet. Understanding the function of the impeller is key to grasping how centrifugal blowers operate efficiently in various applications, including wastewater treatment processes. This principle differentiates centrifugal blowers from other types, such as axial fans, which generate airflow based on different operational mechanics.