Abstract:
A pump comprises a housing partially defining a cavity, an impeller arranged in cavity, the impeller including a first disk, and a vane arranged on the first disk, the impeller operative to rotate about a rotational axis, a first stator core arranged on the housing, windings arranged on the first stator core, and a first inlet defined by the housing, wherein the first inlet, the impeller, and the housing partially define a fluid flow path.

Description:
TECHNICAL FIELD 
       [0001]    The present disclosure relates to pumps, and particularly to an axial-flux induction motor driven centrifugal pump. 
       BACKGROUND 
       [0002]    Centrifugal pumps include a housing with an impeller that is driven by a prime mover to rotate in the housing. Fluid typically enters the pump impeller axially through a suction side intake and is accelerated to flow radially. The housing chamber acts as a diffuser that decelerates the flow of the fluid and increases the pressure of the fluid, which is discharged from an outlet on the pressure side of the pump. 
       SUMMARY 
       [0003]    According to an embodiment, a pump comprises a housing partially defining a cavity, an impeller arranged in cavity, the impeller including a first disk, and a vane arranged on the first disk, the impeller operative to rotate about a rotational axis, a first stator core arranged on the housing, windings arranged on the first stator core, and a first inlet defined by the housing, wherein the first inlet, the impeller, and the housing partially define a fluid flow path. 
         [0004]    According to another embodiment, a pump comprises a housing partially defining a cavity, an impeller arranged in cavity, the impeller including a first disk, a second disk, and a vane arranged between the first disk and the second disk, the impeller operative to rotate about a rotational axis, a first stator core arranged on the housing such that a portion of the first stator core partially defines the cavity, windings arranged on the first stator core, and a first inlet defined by the housing, wherein the first inlet, the impeller, and the housing partially define a fluid flow path. 
         [0005]    According to yet another embodiment, a pump comprises a housing partially defining a cavity, an impeller arranged in cavity, the impeller including a first disk, and a vane arranged on the first disk, the impeller operative to rotate about a rotational axis, a first stator core arranged on the housing such that a portion of the first stator core partially defines the cavity, windings arranged on the first stator core, and a first inlet defined by the housing, wherein the first inlet, the impellor, and the housing partially define a fluid flow path. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    Exemplary embodiments and features of the present disclosure will now be described by way of example only, and with reference to  FIGS. 1 to 6 , of which: 
           [0007]      FIG. 1  illustrates a cut-away view along the line A-A of  FIG. 2  of an exemplary embodiment of an axial-flux induction motor pump. 
           [0008]      FIG. 2  illustrates a side view of the pump of  FIG. 1 . 
           [0009]      FIG. 3  illustrates an alternate exemplary embodiment of a pump. 
           [0010]      FIG. 4  illustrates another alternate exemplary embodiment of a pump. 
           [0011]      FIG. 5  illustrates an example of a fluid flow path. 
           [0012]      FIG. 6  illustrates an alternate embodiment of a pump that includes two fluid inlets. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    Previous centrifugal pumps often included a prime mover such as an electric motor or engine that was coupled to the impeller via a drive shaft. Such pumps were large and heavy, and used bushings and seals that often needed maintenance. 
         [0014]    Some previous centrifugal pumps integrated the pump and motor where the impeller contained permanent magnets such that the impeller acted as the rotor for a brushless direct current (DC) motor. Such pumps produced high axial attractive forces (at zero current state) between the stator and impeller that caused difficulties in practical assembly of the pumps. The magnetic impeller attracted unwanted ferromagnetic debris. The pumps also used more complicated electronics to control the pump motor. 
         [0015]      FIG. 1  illustrates a cut-away view along the line A-A (of  FIG. 2 ) of an exemplary embodiment of an axial-flux induction motor pump  100 . The pump  100  is a centrifugal type pump having a fluid inlet  102  that communicates through a housing  104 . An impeller  106  is arranged in the housing  104  and is arranged to rotate around an axis of rotation  101 . The impeller includes vanes  108  arranged between a first disk  110  and a second disk  112  that secure the vanes  108 . An electrically conductive material  114  is arranged on the first disk  110 . A stator core  116  is arranged proximate to the conductive material  114 . Windings  118  are arranged on the stator core  116 . The stator core  116  and the conductive material  114  define a gap having a gap width (g). In the illustrated embodiment, the stator core  116  is arranged in the housing  104  such that an inner surface (active surface)  119  of the stator core  116  is proximate to the conductive material  114 . The stator core  116  passes through the housing  104  and partially defines the chamber  120  with the housing  104 . In the illustrated embodiment the stator core  116  contacts and partially defines the flow path of the fluid. 
         [0016]    In the illustrated embodiment, the housing  104  may be formed from any suitable material such as, for example, a plastic or polymer material, a nonmagnetic material such as bronze, aluminium, titanium or ceramic, or a ferromagnetic material such as, for example steel or nickel. The first disk  110  is formed from a suitable ferromagnetic material such as, for example, steel, nickel, or another ferromagnetic alloy. The second disk  112  in the illustrated embodiment, may be formed from any suitable material such as, for example, a plastic or polymer material, or a metallic or ceramic material. In the illustrated embodiment, the second disk  112  may be formed from similar or dissimilar materials as the first disk  110 . 
         [0017]    The conductive material  114  arranged in contact with the first disk  110 , and may include a conductive material such as, for example, copper or silver. The stator core  116  may be a single phase or a poly-phase, and may be formed from, for example, a laminated or sintered powder ferromagnetic material. The windings  118  are formed from, for example, copper or aluminium wire that may be wound about the stator core  116 . 
         [0018]    In operation, the first disk  110  conducts both electric current and magnetic flux. Eddy currents induced in the first disk  110  interact with the stator magnetic field to produce electromagnetic torque. The torque is applied to the first disk  110 , which rotates the impeller  106  about the rotational axis  101 . The rotation of the impeller  106  draws fluid through the fluid inlet  102 , and increases the velocity and pressure of the fluid as the fluid flows radially outward. The fluid is discharged from the pump  100  via an outlet  202  (described below in  FIG. 2 ). 
         [0019]    Higher torque is achieved by increasing the current in the first disk  110  and the magnetic flux density in the gap  103  between the first disk  110  and the stator core  116 . The current in the first disk  110  may be increased by reducing the impedance for eddy currents in the first disk  110 . The impedance for eddy currents in the first disk  110  can be decreased by arranging a conductive material  114  having a relatively higher conductivity than the conductivity of the first disk  110  on an outer surface  105  of the first disk  110  such that the conductive material  114  is disposed between the first disk  110  and the stator core  116 . The conductive material  114  may include, for example, copper or silver, and may be, for example, arranged as a coating on the first disk  110  or may be fabricated by securing a disk of the conductive material  114  to the first disk  110 . The arrangement of the conductive material  114  on the disk  110  need not cover the entire outer surface  105  of the disk  110 . In alternate embodiments, for example, the conductive material  114  may be arranged as bands proximate to edges of the first disk  110 . Radial or skewed slots may also be arranged in the first disk  110  to reduce the impedance for eddy currents of the first disk  110  in other alternate embodiments. 
         [0020]      FIG. 2  illustrates a side view of the pump  100 . The windings  118  are shown arranged about the stator core  116 . In  FIG. 2  some of the windings  118  are not shown for clarity. In this regard, in the exemplary embodiment, the windings  118  are arranged axially about the axis of rotation  101  on the stator core  116 .  FIG. 2  illustrates the fluid outlet  202 , which is communicative with the chamber  120 . 
         [0021]      FIG. 3  illustrates an alternate exemplary embodiment of a pump  300 . The pump  300  is similar to the pump  100  (of  FIG. 1 ) described above. The pump  300  includes an additional stator core  116   b  and additional windings  118   b  arranged on a side of the impeller  106  opposing the stator core  116   a  and windings  118   a.  A disk  110   b  that is similar to the disk  110   a  is arranged proximate to the stator core  116   b.  A conductive material  114   b  is arranged on the second disk  110   b.  The operation of the pump  300  is similar to the operation of the pump  100  described above. 
         [0022]      FIG. 4  illustrates another alternate exemplary embodiment of a pump  400 . The pump  400  is similar to the pump  100  (of  FIG. 1 ) however; the stator core  116  is mounted on an outer surface  401  of the housing  104 . In other alternate embodiments, the pump  300  (of  FIG. 3 ) may include stator cores  116   a  and/or  116   b  arranged on the outer surface of the housing  104  of pump  300  in a manner similar to the pump  400 . 
         [0023]      FIG. 5  illustrates an example of the fluid flow path  501  of pump  500  similar to the pumps described above. In the illustrated embodiment the fluid flows through the inlet  102  and radially outward from the axis of rotation  101  of the impeller  106 . The fluid flows through the gap  103  partially defined by the housing  104 , the stator core  116  and the conductive material  114 . 
         [0024]      FIG. 6  illustrates an alternate embodiment of a pump  600  that includes two fluid inlets, a first fluid inlet  102  and a second fluid inlet  602  opposing the first fluid inlet  102 . The fluid flow path  601  is partially defined by the first fluid inlet  102  and the second fluid inlet  602 . The arrangement of the inlets  102  and  602  of  FIG. 6  may be used in any of the embodiments described above. 
         [0025]    The embodiments of a centrifugal pump described above offer a low cost, compact, high speed pump that may be used in a number of fluid systems. The pump avoids using permanent magnets, which attract unwanted ferromagnetic debris. The pump has low susceptibility to electromagnetic interference, and may be assembled easily. 
         [0026]    Although the figures and the accompanying description describe particular embodiments, it is to be understood that the scope of this disclosure is not to be limited to such specific embodiments, and is, instead, to be determined by the scope of the following claims.