Centrifugal pump

A centrifugal pump comprising:

• a head part;
• a foot part;
• a plurality of pump stages, which are arranged axially between the head part and the foot part;
• a fastener;
• an outer casing which peripherally surrounds the pump stages, wherein an axial end of the outer casing is fastened on the head part and the other axial end of the outer casing on the foot part, wherein a mechanical connection between the head part and the foot part is formed by the outer casing, wherein the outer casing comprises an outer casing radius, the outer casing radius being constant in an area adjacent to at least one end of the outer casing, wherein the outer casing radius increases at the least one end, at least the fastener connecting the outer casing to the foot part, the fastener being located at a spaced location from the outer casing;
• and
• at least one ring, wherein the outer casing is connected with a positive fit at least one of to the foot part and to the head part by way of integrating the at least one ring, wherein the at least one ring is in contact with a fastener receiving structure and an outer surface of the at least one end, the fastener receiving structure being located radially outward of the outer casing, the fastener receiving structure comprising at least one opening, the at least one opening receiving at least a portion of the fastener.