Canned motor pump and method for manufacturing such a motor pump

Abstract

The invention relates to a canned motor pump (P 1 ) comprising: a housing ( 10 ) including a body ( 11 ) and a motor casing ( 12 ); an electric motor ( 20 ) including a stator ( 30 ) and a rotor ( 40 ) arranged in the motor casing ( 12 ); a shaft ( 50 ), extending along a central axis (X 1 ), secured with the rotor ( 40 ) to rotate therewith about the central axis (X 1 ), and having a front end ( 52 ) located outside the motor casing ( 12 ), in the body ( 11 ) of the housing ( 10 ); and a wheel ( 60 ) located at the front end ( 52 ) of the shaft ( 50 ), secured with the shaft ( 50 ) to rotate therewith about the central axis (X 1 ) and having a hydraulic profile suitable for moving a fluid (F) in the body ( 11 ). The rotor ( 40 ), the shaft ( 50 ) and the wheel ( 60 ) form a rotary assembly (ER 1 ). Within the rotary assembly (ER 1 ), only the shaft ( 50 ) is supported by one or more bearings ( 80 ), thereby guiding the rotary assembly (ER 1 ) in rotation. The motor pump (P 1 ) is characterized in that the shaft ( 50 ) and the wheel ( 60 ) form, at least partially, a single-piece part ( 70 ). A method for manufacturing such a motor pump (P 1 ) is also described.

1 . Canned motor pump (P 1 ; P 2 ) comprising:
 a housing ( 10 ) comprising a body ( 11 ) and a motor casing ( 12 );   an electric motor ( 20 ) comprising a stator ( 30 ) and a rotor ( 40 ) arranged within the motor casing ( 12 );   a shaft ( 50 ) which extends along a central axis (X 1 ), which is secured to the rotor ( 40 ) in rotation about the central axis (X 1 ), and which has a front end ( 52 ) situated outside the motor casing ( 12 ), within the body ( 11 ) of the housing ( 10 ); and   a wheel ( 60 ) which is located at the front end ( 52 ) of the shaft ( 50 ), which is secured to the shaft ( 50 ) in rotation about the central axis (X 1 ), and which has a hydraulic profile suitable for moving a fluid (F) within the body ( 11 );   
       the rotor ( 40 ), the shaft ( 50 ) and the wheel ( 60 ) forming a rotary assembly (ER 1 ; ER 2 ); and within the rotary assembly (ER 1 , ER 2 ), only the shaft ( 50 ) is supported by one or more bearings ( 80 ;  8 ,  9 ), thus guiding the rotary assembly (ER 1 , ER 2 ) in rotation; wherein the shaft ( 50 ) and the wheel ( 60 ) constitute at least partly a unitary part ( 70 ). 
     
     
         2 . Canned motor pump (P 1 ; P 2 ) according to  claim 1 , wherein the shaft ( 50 ) and the wheel ( 60 ) integrally constitute a single unitary part ( 70 ). 
     
     
         3 . Canned motor pump (P 1 ; P 2 ) according to  claim 1 , wherein the wheel ( 60 ) comprises a central portion ( 61 ), which is located on the central axis (X 1 ), belongs to the unitary part ( 70 ), and has no attachment system. 
     
     
         4 . Canned motor pump (P 1 ; P 2 ) according to  claim 3 , wherein the central part ( 61 ) forms an inducer. 
     
     
         5 . Canned motor pump (P 1 ; P 2 ) according to  claim 3 , wherein the central portion ( 61 ) includes an extension to the blades ( 62 ) of the wheel ( 60 ). 
     
     
         6 . Canned motor pump (P 1 ) according to  claim 1 , wherein the canned motor pump (P 1 ) comprises a single bearing ( 80 ) supporting the shaft ( 50 ) radially to the central axis (X 1 ) for guide the rotary assembly (ER 1 ) in rotation, and which is located between the rotor ( 40 ) and the wheel ( 60 ) along the central axis (X 1 ). 
     
     
         7 . Canned motor pump (P 2 ) according to  claim 1 , wherein the canned motor pump (P 2 ) comprises a front bearing ( 8 ) and a rear bearing ( 9 ) supporting the shaft ( 50 ) radially to the central axis (X 1 ) for guiding the rotary assembly (ER 2 ) in rotation, the front bearing ( 8 ) being located between the rotor ( 40 ) and the wheel ( 60 ) along the central axis (X 1 ). 
     
     
         8 . Canned motor pump (P 1 ; P 2 ) according to  claim 1 , wherein the electric motor ( 20 ) is constructed according to synchronous motor technology with magnets at the rotor ( 40 ). 
     
     
         9 . Canned motor pump (P 1 ; P 2 ) according to  claim 1 , wherein the stator ( 30 ), comprising an electromagnetic core ( 31 ) and a winding ( 32 ) has an inner surface entirely enveloped in a non-metallic material, facing the rotor ( 40 ) and in contact with the fluid (F) circulating within the motor casing ( 12 ). 
     
     
         10 . Canned motor pump (P 1 ; P 2 ) according to  claim 9 , wherein the stator ( 30 ) is embedded in a sealed resin coating ( 33 ), at least along the inner surface. 
     
     
         11 . Canned motor pump (P 1 ; P 2 ) according to  claim 1 , wherein the canned motor pump (P 1 ; P 2 ) is a centrifugal pump, the hydraulic profile of the wheel ( 60 ) being suitable for the transmission of energy by the centrifugation of fluid (F). 
     
     
         12 . A method for manufacturing a canned motor pump (P 1 ; P 2 ) according to  claim 1 , wherein the shaft ( 50 ) and the wheel ( 60 ) are at least partially manufactured in the form of a unitary part ( 70 ), according to a technique of sand casting, metal mold casting or lost wax casting, sintering, welding, additive fabrication, or a combination of several techniques. 
     
     
         13 . A method for manufacturing a canned motor pump (P 1 ; P 2 ) according to  claim 12 , wherein the method comprises an operation of additive fabrication of the unitary part ( 70 ). 
     
     
         14 . A method of manufacturing a canned motor pump (P 1 ; P 2 ) according to  claim 12 , wherein the method comprises an operation of additive fabrication of at least a portion of a mold comprising a cavity corresponding to the unitary part ( 70 ), and then an operation of fabrication of the unitary part ( 70 ) within this mold.