Centrifugal pump

Abstract

A rotor (13) and a pump body (2) are arranged in a concentric manner around a rotor shaft (7), and a suction side scroll flow path (14) and a discharge side scroll flow path (15) formed in the pump body (2) communicate with each other via central flow paths (10b), (10a) formed in the pump body (2) and an impeller (9).

1 . A centrifugal pump that causes a radial gap-type electric motor to rotationally drive an impeller to suction a fluid from an outer circumference side of a pump body into a pump chamber and discharge the fluid from the pump chamber via the outer circumference side of the pump body, the centrifugal pump comprising:
 a base portion;   a rotor shaft having at least one end prevented from dropping off and supported by the base portion in a standing manner;   the impeller rotatably attached to the rotor shaft;   a rotor including a rotor magnet mounted to the impeller in a concentric fashion; and   the pump body in which a suction side scroll flow path that suctions the fluid from an outer circumference side of the impeller toward a radially central portion thereof, a discharge side scroll flow path that discharges the fluid from the radially central portion of the impeller toward the outer circumference side thereof, and a stator including a stator core having stator pole teeth formed and placed to face radially the rotor magnet are integrally mounted,   wherein the rotor and the pump body are placed in a concentric fashion around the rotor shaft, and the suction side scroll flow path and the discharge side scroll flow path formed in the pump body communicate with each other via central flow paths formed in the pump body and the impeller.   
     
     
         2 . The centrifugal pump according to  claim 1 , wherein the suction side scroll flow path includes a suction hole provided on an outer circumference surface of the pump body and a suction side scroll groove partitioned in such a manner that the fluid entering from the suction hole is guided toward a suction side central hole while revolving in a circumferential direction and formed in such a manner that a groove depth thereof becomes shallower as the groove depth goes from the suction hole toward the suction side central hole. 
     
     
         3 . The centrifugal pump according to  claim 2 , wherein the suction side scroll flow path is formed between the suction side scroll groove formed on one end portion in an axial direction of the pump body and a base portion superposed on the one end portion in the axial direction. 
     
     
         4 . The centrifugal pump according to  claim 1 , wherein the discharge side scroll flow path includes a discharge side central hole formed in such a way as to communicate with the suction side central hole via the central flow paths and a discharge side scroll groove partitioned in such a manner that the fluid is guided from the discharge side central hole to a discharge hole provided on an outer circumference surface of the pump body while revolving and formed in such a manner that a groove depth thereof becomes deeper as the groove depth goes from the discharge side central hole toward the discharge hole. 
     
     
         5 . The centrifugal pump according to  claim 4 , wherein the discharge side scroll flow path is formed between the discharge side scroll groove formed on the other end portion in the axial direction of the pump body and a base portion superposed on the other end portion in the axial direction. 
     
     
         6 . The centrifugal pump according to  claim 1 , wherein, on end surfaces in the axial direction of the pump body, a shallow groove and a deep groove are placed while being combined such that groove bottom portions thereof are close to each other in such a manner that a flow velocity of the fluid becomes uniform in the suction side scroll flow path and the discharge side scroll flow path. 
     
     
         7 . The centrifugal pump according to  claim 1 , wherein the impeller includes an annular portion, to which the rotor is mounted, and a blade portion, which is mounted to the rotor shaft, the annular portion and the blade portion being molded integrally with each other.