Abstract: A centrifugal pump includes a volute and an impeller that are disposed in a pump chamber accessible through an access opening in the front wall of the pump's casing. The access opening is normally closed by a cover attachable to a front wall of the casing. The volute is attached to the cover by fasteners accessible from the outside of the cover so as to permit the cover and volute to be removed either as a unit or individually. The volute therefore is more easily accessed and removed than conventional pump volutes. In order to maximize self-priming and suction lift capability, the volute includes a discharge duct that converts substantially circular flow at the inlet of the discharge duct to substantially tangential flow at the outlet of the discharge duct, thereby maximizing the separation of air from the discharged liquid stream and minimizing the amount of entrained air in that portion of the discharged liquid stream that is recirculated to a recirculation inlet of the self-priming pump.