Self-priming centrifugal pumps are ideal for pumping slightly contaminated liquids with or without solid parts. Self-priming pumps are used in systems where priming can sometimes be difficult and where a regular end suction centrifugal pump doesn’t work. Once the pump casing is filled with liquid, pumping air from the suction pipe is extremely simple. 

The rotation of the impeller draws the air present in the suction pipe into the pump casing. The air mixes with the liquid present in the pump casing. Liquid and air are transported to the discharge outlet. When all the air has been removed from the suction pipe, the pump draws in liquid.