Which type of pump typically does not require priming before use?

Rotary pumps are designed to create a continuous flow by using mechanical means to move the fluid, often relying on rotating elements such as gears or vanes. These pumps can operate effectively without the need for priming because they are capable of drawing fluid into the pump chamber as it operates, utilizing the action of the rotating components. This ability enables rotary pumps to handle fluids with varying viscosities and can self-prime in many instances.

In contrast, diaphragm pumps, reciprocating pumps, and centrifugal pumps typically require priming to remove air from the suction line and ensure that the pump is filled with liquid before it begins to operate. Without proper priming, these pumps may not generate adequate suction, leading to cavitation or other operational issues. This distinctive characteristic of rotary pumps distinguishes them from the other types mentioned, affirming their ability to function without prior priming in many applications.