ZX series self-priming pump falls into the category of self-priming centrifugal pump,which has such advantages as compact structure, easy operation, stable running, easy maintenance, high efficiency, long life and strong self-priming capacity. The bottom valve needn't be mounte in the pipeline. It ′s only necessary to reserve a fixed quantity of guide liquid in the pump body before work. Therefore, it simplifies the pipeline system and also improves the labor conditions.