This series pumps are with peripheral impeller containing numerous radial blades in its edge. Self-priming because the particular design of the pump body ensures the elimination of any air in the suction piping. The re-circulation of the pumped fluid induced by the particular shape of the pump body permits the self-priming effect, extracting and completely expelling any air in the suction piping. The fluid pressure increases progressively as it passes from the suction opening to the delivery opening, ensuring an even, non-pulsing flow and high pressures with particularly steep curves.