Pump casing

Abstract

A pump casing for a centrifugal pump, which comprises an inlet opening, a discharge outlet, 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. The transition surface has a cutwater having 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.

1 - 8 . (canceled) 
     
     
         9 . A pump casing for a centrifugal pump having a main pumping chamber, the pump casing comprising:
 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 being positioned 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; and   a cutwater formed at the transition surface, wherein when the transition surface is viewed from a line through a central axis of the casing, the line being parallel to a tangential line at the discharge outlet, the cutwater has a profiled section which comprises a removable protrusion connected to the transition surface.   
     
     
         10 . A pump casing according to  claim 9 , wherein the main pumping chamber is of generally volute shape. 
     
     
         11 - 18 . (canceled) 
     
     
         19 . A pump casing according to  claim 9 , wherein the pump casing is in the form of a liner for a pump having an outer housing. 
     
     
         20 - 26 . (canceled) 
     
     
         27 . A centrifugal pump having a pump casing with a main chamber therein, an inlet opening and a discharge outlet, and an impeller disposed within the main chamber and mounted for rotation on an impeller shaft, said pump casing further comprising 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 being 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, and further wherein, when viewed from a line through a central axis of the pump 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 that 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. 
     
     
         28 . The centrifugal pump according to  claim 27  wherein the pump casing is in the form of a liner disposed within an outer casing. 
     
     
         29 . (canceled) 
     
     
         30 . A centrifugal pump having a pump liner defining a main chamber therein, and having an inlet opening, a discharge outlet, and an impeller disposed within the main chamber and mounted for rotation on an impeller shaft, the pump liner further comprising two side parts which can be fitted together so that the pump liner comprises the main pumping chamber, an inlet to the main pumping chamber and a discharge outlet extending from the main pumping chamber, said main pumping chamber and said discharge outlet each having an inner peripheral surface, a transition portion having a transition surface between the inner peripheral surfaces of said pumping chamber and said discharge outlet, said transition portion including a cutwater wherein each of said side parts comprises a part of the main pumping chamber, the discharge outlet and the transition portion, and wherein each part of said transition portion has reinforcement associated therewith, said reinforcement including a projection on one of the parts of the transition portion and a co-operating recess on the other of the parts of the transition portion, the projection being receivable within the recess when the side parts are fitted together. 
     
     
         31 . A method of fitting a liner within a pump, comprising:
 providing a pump housing having an inlet opening arranged for the introduction of a flow of material into the pump housing during use, a discharge outlet positioned for extending from a main pumping chamber and arranged for the exit of a flow of material from a main pumping chamber and a transition surface extending between an inner surface for receiving the peripheral surface a main pumping chamber and an inner peripheral surface of the discharge outlet, the transition surface being arranged for separating an in use exit flow of material in the discharge outlet from an in use recirculation flow of material a main pumping chamber;   providing a pump liner configured for positioning within a pump housing, the pump liner having two side parts which are structured to be fitted together so that the pump liner comprises a main pumping chamber within a pump housing, an inlet to the main pumping chamber and a discharge outlet extending from the main pumping chamber, the main pumping chamber and the discharge outlet each having an inner peripheral surface, a transition portion having a transition surface between the inner peripheral surface of the main pumping chamber and the inner peripheral surface of the discharge outlet, the transition portion including a cutwater, and wherein each of the side parts of the pump liner comprises part of the main pump chamber, the discharge outlet and the transition portion, and wherein each part of the transition portion has reinforcement associated therewith;   positioning each of said pump liner side parts within the pump housing to align the inlet of the pump liner side parts with the inlet of the pump housing and arranging the discharge outlet of each side part in location with the discharge outlet of the pump housing; and   securing one side part of the pump liner to the other side part of the pump liner at the transition portion by engagement of the reinforcement arrangement associated with the transition portion of each side part of the pump liner.