What is a pump with an impeller spinning inside of a volute called?

A pump with an impeller spinning inside of a volute is classified as a centrifugal pump. This type of pump operates based on the principle of converting rotational kinetic energy, typically produced by a motor-driven impeller, into hydrodynamic energy, resulting in the movement of fluid. The fluid enters the pump at the center of the impeller and is propelled outward due to centrifugal force into the volute, which gradually increases in cross-sectional area to convert the high velocity of the fluid into pressure.

Centrifugal pumps are widely used in various applications, including water supply, waste treatment, and many industrial processes, due to their efficiency and ability to handle large volumes of fluid. The configuration of the impeller and volute is specifically designed to optimize the conversion of energy and ensure smooth fluid flow.

The other choices represent different types of pumps that do not operate based on the same principles. For example, gear pumps rely on rotating gears to move fluid, submersible pumps are designed to function underwater, and diaphragm pumps utilize a flexible diaphragm to create a pumping action. These designs and mechanisms differentiate them from the behavior and function of a centrifugal pump.