Progressing cavity pump/motor

Abstract

A progressing cavity pump/motor includes a stator ( 12 ) having a metal interior surface ( 14 ) and one or more spiraling internal lobes ( 16 ). The rotor ( 18 ) has a metal exterior surface ( 20 ) and one or more spiraling external lobes ( 22 ) for cooperating with the stator to form progressing cavities between the stator and the rotor during rotation of the rotor. At least one of the stator interior surface and the rotor exterior surface include a plurality of spaced grooves ( 30 ) in the respective surface, such that fluid flowing to a gap between the stator and the rotor is disrupted by the spaced grooves to reduce fluid leakage between the stator and the rotor.

What is claimed is: 
     
         1 . A progressing cavity pump/motor, comprising:
 a stator having an interior surface and two or more spiraling internal lobes;   a rotor having an external surface and one or more spiraling external lobes, the rotor cooperating with the stator to form progressing cavities between the stator and the rotor during rotation of the rotor; and   at least one of the stator interior surface and the rotor exterior surface having a plurality of spaced grooves in the respective surface and spaced substantially along the length of the respective stator interior surface or rotor exterior surface, such that fluid flowing through a gap between the stator and the rotor is disrupted by the spaced grooves to reduce fluid leakage between the stator and the rotor.   
     
     
         2 . A progressing cavity pump/motor as defined in  claim 1 , wherein each of the plurality of spaced grooves is substantially parallel to a centerline of the respective spiraling lobe. 
     
     
         3 . A progressing cavity pump/motor as defined in  claim 1 , wherein at least one of the plurality of spaced grooves is a stepped groove having a first portion with shallower depth than a second portion. 
     
     
         4 . A progressing cavity pump/motor as defined in  claim 1 , wherein at least one of the plurality of spaced grooves has a curvilinear cross-sectional configuration. 
     
     
         5 . A progressing cavity pump/motor as defined in  claim 1 , wherein grooves are provided in sets of two or more differently configured grooves, with a respective surface spaced between groove sets. 
     
     
         6 . A progressing cavity pump/motor as defined in  claim 1 , wherein a surface spacing between grooves or sets of grooves is from 0.1 to 1.2 inches. 
     
     
         7 . A progressing cavity pump/motor as defined in  claim 1 , wherein the plurality of spaced grooves are formed on the interior surface of the stator. 
     
     
         8 . A progressing cavity pump/motor as defined in  claim 1 , wherein each of the plurality of grooves has a groove depth from the respective surface of from 0.001 inches to 0.100 inches. 
     
     
         9 . A progressing cavity pump/motor, comprising:
 a stator formed having an interior surface and two or more spiraling internal lobes;   a rotor having an external surface and one or more spiraling external lobes, the rotor cooperating with the stator to form progressing cavities between the stator and the rotor during rotation of the rotor; and   at least one of the stator interior surface and the rotor exterior surface having a plurality of spaced grooves in the respective surface, each of the plurality of spaced grooves being substantially parallel to a centerline of the respective spiraling lobe, such that fluid flowing to a gap between the stator and the rotor is disrupted by the spaced grooves to reduce fluid leakage between the stator and the rotor.   
     
     
         10 . A progressing cavity pump/motor as defined in  claim 9 , wherein at least one of the plurality of spaced grooves is a stepped groove having a first portion with shallower depth than a second portion. 
     
     
         11 . A progressing cavity pump/motor as defined in  claim 9 , wherein at least one of the plurality of spaced grooves has a curvilinear cross-sectional configuration. 
     
     
         12 . A progressing cavity pump/motor as defined in  claim 9 , wherein each of the plurality of grooves has a groove depth from the respective surface of from 0.001 inches to 0.100 inches. 
     
     
         13 . A progressing cavity pump/motor as defined in  claim 9 , wherein a surface spacing between grooves or sets of grooves is 0.1 to 1.2 inches. 
     
     
         14 . A progressing cavity pump/motor as defined in  claim 9 , wherein the plurality of spaced grooves are formed on the interior surface of the stator. 
     
     
         15 . A progressing cavity pump/motor as defined in  claim 9 , wherein the plurality of spaced grooves are formed on the exterior surface of the rotor. 
     
     
         16 . A stator for a progressing cavity pump/motor including a rotor having a substantially rigid external surface and one or more spiraling external lobes, the rotor cooperating with the stator to form progressing cavities between the stator and the rotor during rotation of the rotor, the stator comprising:
 the stator having a substantially rigid interior surface and two or more spiraling internal lobes; and   the stator interior surface having a plurality of spaced grooves, such that fluid flowing through a gap between the stator and the rotor is disrupted by the spaced grooves to reduce fluid leakage between the stator and the rotor.   
     
     
         17 . A stator as defined in  claim 16 , wherein each of the plurality of spaced grooves is substantially parallel to a centerline of a stator spiraling lobe. 
     
     
         18 . A stator as defined in  claim 16 , wherein at least one of the plurality of spaced grooves is a stepped groove having a first portion with shallower depth than a second portion. 
     
     
         19 . A stator as defined in  claim 16 , wherein each of the plurality of grooves has a groove depth from the respective surface of from 0.001 inches to 0.100 inches. 
     
     
         20 . A stator as defined in  claim 16 , wherein at least one of the plurality of spaced grooves has a curvilinear cross-sectional configuration.