What type of pump is typically used as the priming pump for a centrifugal pump?

The use of a rotary pump as a priming pump for a centrifugal pump is based on the operational characteristics of both types of pumps. A rotary pump can effectively create a vacuum to evacuate air from the suction side of the centrifugal pump, allowing it to draw water in and establish the necessary suction. This is critical because a centrifugal pump relies on the presence of liquid in its impeller to function properly.

Rotary pumps, which include gear pumps and vane pumps, can move liquid through mechanical action driven by the rotating elements. They are effective in providing the initial flow required to fill the centrifugal pump with liquid, enabling it to start operating efficiently.

In contrast, a centrifugal pump does not have the capability to self-prime when air is present, which is why a priming pump, like a rotary pump, is essential for the initial startup. Positive-displacement pumps serve different functions and are used in applications requiring a consistent flow rate irrespective of pressure changes, while a fire pump is a term that encompasses various types of pumps used specifically for firefighting applications. Thus, the rotary pump stands out as the most suitable choice for the priming process of a centrifugal pump.