A centrifugal pump is of kinetic energy type - it imparts energy to a liquid by means of centrifugal force produced by a impeller, disk or other blade form. Centrifugal pumps are made in many shapes and sizes, and differ from one another both internally and externally to an appreciable degree. In spite of appearance, all centrifugal pumps use the same mechanical principle. Pumping action is obtained from an impeller driven by a shaft or magnetic coupling which is connected to a motor or some other driving device. The impeller rotates (cw or ccw direction of rotation) at a high rate of speed (usually 1725 or 3450 rpm), and the liquid being pumped flows from the eye (center) of the impeller to the outside (periphery) of the impeller by centrifugal action. As the liquid flows from the periphery of the impeller, it is guided to the discharge port of the pump by a volute shaped passage. All centrifugal pumps bring liquid in at the center of the impeller, and move it outward between the blades.
