A centrifugal pump is not a blower or fan and is unable to pump air. If the impeller is completely surrounded by air, it will invariably lose its prime. However, it can pass a small amount of air dispersed throughout the fluid. A priming chamber within the pump allows this small amount of air to pass through the pump gradually, directing it to the discharge line. Key to this technology is that the impeller must remain completely submerged and surrounded by the fluid. If the amount of air passing through the pump becomes too great, and the impeller becomes surrounded by too much air, the pump will lose its prime. In this way, air is pulled into the fluid path slowly and then exits the pump, and the resulting vacuum pulls the fluid up through the suction line. Eventually, all the air is evacuated from the suction line, and the pump is fully primed.