Which component is essential for creating a vacuum to lift liquids in a centrifugal pump?

The impeller is the critical component in a centrifugal pump that creates the necessary forces to lift liquids, including the creation of a vacuum when priming or operating under certain conditions. It operates by converting rotational energy into kinetic energy, which accelerates the liquid and pushes it outward. As the liquid moves from the center of the impeller to its outer edges, a drop in pressure occurs at the impeller's inlet, which can facilitate the development of a vacuum.

This vacuum effect is crucial for drawing fluid into the pump, especially when the pump is initially primed or when it is working with liquids at low levels. The design and functionality of the impeller directly influence the pump's ability to lift the liquid against gravity, making it essential for the overall operation.

Other components, such as the diffuser, motor, and casing, serve important roles in the pump’s operation but are not directly responsible for creating the vacuum. The diffuser helps convert kinetic energy from the impeller into pressure energy, while the motor provides the necessary power for the impeller to rotate. The casing acts as a housing that contains the fluid and supports the impeller's function. However, without the impeller's action in generating low pressure at the inlet, the vacuum necessary for liquid