Pump assembly for a dishwashing appliance

Abstract

A dishwasher appliance includes a sump housing defining a sump for collecting wash fluid, the sump defining a recirculation chamber, a soil collection chamber, and a rotor housing positioned between the recirculation chamber and the soil collection chamber. A rotor assembly is positioned in the rotor housing and includes a concentric central hub and annular rotor magnet spaced apart to define a flow path between the recirculation chamber and the soil collection chamber. A plurality of helical vanes extend between the central hub and the annular rotor magnet and the annular rotor magnet is selectively rotated by a stator assembly positioned around the rotor housing outside of the sump.

What is claimed is: 
     
         1 . A dishwasher appliance defining a vertical direction, the dishwasher appliance comprising:
 a wash tub that defines a wash chamber;   a sump housing defining a sump for collecting wash fluid, the sump defining a recirculation chamber, a soil collection chamber, and a rotor housing positioned between the recirculation chamber and the soil collection chamber;   a rotor assembly rotatably mounted within the rotor housing; and   a stator assembly positioned around the rotor housing outside of the sump for selectively rotating the rotor assembly.   
     
     
         2 . The dishwasher appliance of  claim 1 , further comprising:
 a drive shaft defining an axial direction and a radial direction perpendicular to the axial direction;   a top bearing mounted within a wash pump housing; and   a bottom bearing mounted at a bottom of the sump housing.   
     
     
         3 . The dishwasher appliance of  claim 2 , wherein the rotor assembly comprises:
 a central hub coupled to the drive shaft;   an annular rotor magnet positioned concentrically around the central hub and defining a flow path through the rotor housing between the recirculation chamber and the soil collection chamber; and   a plurality of helical vanes that extend between the central hub and the annular rotor magnet.   
     
     
         4 . The dishwasher appliance of  claim 3 , wherein the plurality of helical vanes is three vanes. 
     
     
         5 . The dishwasher appliance of  claim 3 , the plurality of helical vanes within the flow path defines a void radio of less than 10 percent. 
     
     
         6 . The dishwasher appliance of  claim 2 , wherein the stator assembly is operable to rotate the drive shaft in a first direction during a wash cycle and in a second direction during a drain cycle, the second direction being opposite the first direction. 
     
     
         7 . The dishwasher appliance of  claim 2 , wherein the drive shaft extends parallel to the vertical direction defined by the dishwasher appliance. 
     
     
         8 . The dishwasher appliance of  claim 1 , further comprising:
 a wash pump housing defining an inlet; and   a wash pump impeller positioned within the wash pump housing and being coupled to a drive shaft for drawing wash fluid through the inlet from the recirculation chamber.   
     
     
         9 . The dishwasher appliance of  claim 8 , wherein the inlet faces down along the vertical direction. 
     
     
         10 . The dishwasher appliance of  claim 1 , wherein the soil collection chamber is positioned below the rotor assembly and the recirculation chamber is positioned above the rotor assembly. 
     
     
         11 . The dishwasher appliance of  claim 1 , further comprising:
 a discharge conduit fluidly coupled to the soil collection chamber.   
     
     
         12 . The dishwasher appliance of  claim 11 , further comprising:
 a check valve operably coupled to the discharge conduit to prevent a flow of wash fluid through the discharge conduit into the soil collection chamber.   
     
     
         13 . A pump assembly for a dishwashing appliance, the dishwashing appliance comprising a sump housing defining a sump for collecting wash fluid, the sump defining a recirculation chamber, a soil collection chamber, and a rotor housing positioned between the recirculation chamber and the soil collection chamber, the pump assembly comprising:
 a drive shaft defining an axial direction and a radial direction perpendicular to the axial direction;   a rotor assembly coupled to the drive shaft and being rotatably mounted within the rotor housing; and   a stator assembly positioned around the rotor housing outside of the sump for selectively rotating the rotor assembly.   
     
     
         14 . The pump assembly of  claim 13 , wherein the rotor assembly comprises:
 a central hub coupled to the drive shaft;   an annular rotor magnet positioned concentrically around the central hub and defining a flow path through the rotor housing between the recirculation chamber and the soil collection chamber; and   a plurality of helical vanes that extend between the central hub and the annular rotor magnet.   
     
     
         15 . The pump assembly of  claim 14 , wherein the plurality of helical vanes is three vanes. 
     
     
         16 . The pump assembly of  claim 14 , the plurality of helical vanes within the flow path defines a void radio of less than 10 percent. 
     
     
         17 . The pump assembly of  claim 13 , further comprising:
 a wash pump housing defining an inlet facing down along a vertical direction; and   a wash pump impeller positioned within the wash pump housing and being coupled to the drive shaft for drawing wash fluid through the inlet from the recirculation chamber.   
     
     
         18 . The pump assembly of  claim 13 , wherein the soil collection chamber is positioned below the rotor assembly and the recirculation chamber is positioned above the rotor assembly. 
     
     
         19 . The pump assembly of  claim 13 , further comprising:
 a discharge conduit fluidly coupled to the soil collection chamber.   
     
     
         20 . The pump assembly of  claim 19 , further comprising:
 a check valve operably coupled to the discharge conduit to prevent a flow of wash fluid through the discharge conduit into the soil collection chamber.