The self-priming pump has the advantages of compact structure, convenient operation, stable operation, easy maintenance, high efficiency, long life, and strong self-priming ability. The advantages of centrifugal pumps are compact structure, wide range of flow and head, suitable for mildly corrosive liquids, multiple control options, uniform flow, stable operation, low vibration, no need for special shock absorption foundation, equipment installation, Maintenance and repair costs are low.