Abstract: A centrifugal pump with a volute and at least one stage with an associated impeller and removable diffuser assembly comprises: multiple diffuser segments, each diffuser segment comprising a central passage from an inner curvilinear surface to an outer curvilinear surface and a curvilinear leading engagement surface between a leading end of its curvilinear inner surface and its curvilinear outer surface; multiple curvilinear volute mounting surfaces within the volute, each curvilinear mounting surface receiving a corresponding diffuser segment to mount the diffuser segments in a generally annular pattern about the impeller to form the removable diffuser assembly, with the curvilinear inner surface of each diffuser segment proximate an outer periphery of the impeller and the curvilinear leading engagement surface of each diffuser segment engaging a trailing portion of the curvilinear outer surface of an adjacent one of the diffuser segments; and a volute connecting passage within the volute for coupling the cen