SELF-PRIMING PUMP ASSEMBLY

The invention relates to a self-priming pump assembly which is a series connection of a liquid ring pump which operates as a rotating positive-displacement pump and a non-self-priming centrifugal pump, according to the preamble of claim 1. The invention develops the self-priming pump assembly of the generic type in such a way that the flow conditions for the flow of fluids to and in the return line are improved. This is achieved by virtue of the fact that the first connector opening (9a) has, in the meridian plane of the centrifugal pump (2), a bulge (33) which sectorally encloses a longitudinal axis (a3) of the first connector opening (9a), that the bulge (33) is oriented on one side and towards a rotational axis (a1) of the pump assembly (1), that the bulge (33) continuously widens the first connector opening (9a) towards the impeller plane directly or indirectly, and that the bulge (33) merges, at its end section which faces the impeller plane, by way of a transition surface (34) continuously into the late