Patent ID: 8747062

Claim:
A pump casing for a centrifugal pump, the pump casing including a main pumping chamber having: an inlet opening arranged for the introduction of a flow of material into the main pumping chamber during use; a discharge outlet extending from the main pumping chamber and arranged for the exit of a flow of material from the main pumping chamber during use; and a transition surface extending between an inner peripheral surface of the main pumping chamber and an inner peripheral surface of the discharge outlet, the transition surface arranged for separating an in use exit flow of material in the discharge outlet from an in use recirculation flow of material in the main pumping chamber; wherein when viewed from a line through a central axis of the casing, said line being parallel to a tangential line at the discharge outlet, said transition surface has a cutwater with a profiled section which comprises a protrusion which extends irregularly from an otherwise generally rounded arched or U-shaped transition surface and is configured such that, in use, the velocity and/or turbulence resulting from the in use flow of the material being pumped in the main pumping chamber is reduced.