Tennessee Wastewater Operator Practice Exam

In centrifugal blower operation, what is the primary purpose of the impeller?

1. To filter air

2. To increase the pressure of the air

3. To reduce noise

4. To cool the system

The correct answer is: To increase the pressure of the air

The primary purpose of the impeller in a centrifugal blower is to increase the pressure of the air. The impeller works by drawing in air at the inlet and then rapidly spinning it, which converts the kinetic energy of the spinning blades into pressure energy. As the air is thrown outward due to the centrifugal force generated by the rotation of the impeller, it exits the blower with higher velocity and pressure compared to its intake. This increase in pressure is critical for applications that require air to be moved effectively against resistance, such as in aeration processes, conveying systems, or various other applications in wastewater treatment facilities. The efficiency of the impeller design and operation directly impacts the performance of the centrifugal blower, making it a vital component in achieving the desired air flow and pressure levels. Other options like filtering air, reducing noise, or cooling the system do not represent the primary function of an impeller. While components of a blower system might serve those purposes through separate mechanisms, the impeller’s main role revolves around pressure enhancement, which is essential for effective operation in many industrial processes.