Positive displacement rotary pump and drive coupling therefor

Abstract

A progressing cavity, positive displacement rotary pump assembly for fluid or semi-fluid material. The assembly includes a rotary shaft with an associated drive motor and pump components including a tubular stator with an interior helical surface and an orbital rotor within the stator operably connected to the shaft and having an exterior helical surface. The helical rotor surface has one more thread than the helical stator surface which it engages, to define sealed pumping cavities that advance axially as the rotor rotates and orbits within the stator. The rotor is coupled to the shaft by a flexible torque tube with one end connected to the shaft and the other connected to an end of the rotor to transmit driving torque to the rotor and to flex sufficiently to accommodate orbital movement of the rotor.

I claim: 
     
       1. In a progressing-cavity, positive displacement rotary pump assembly including a rotary shaft and drive means therefor, a generally tubular stator coaxial with said rotary shaft and having a helically formed interior surface with n-1 threads, a rotor located within said stator and having a helically formed exterior surface engaging said interior surface of said stator to define therewith, sealed pumping cavities, said exterior rotor surface having n threads and a lead of n times the lead of said interior stator surface, the improvement which comprises: a flexible tubular member .Iadd.surrounding at least a portion of said shaft whereby said shaft extends through said flexible tubular member and through said rotor .Iaddend.for coupling said rotor to said shaft, one end of said member being rigidly connected to said shaft and the other end thereof being rigidly connected to said rotor to transmit driving torque to said rotor and to flex to accommodate orbital movement of said rotor during rotation thereof.   
     
     
       2. A submersible grinder pump for comminuting and pumping semi-fluid material from a reservoir, comprising: a stationary housing assembly,   a rotary shaft with a generally vertical axis,   a rotary drive means for said shaft operatively connected to the upper end thereof,   rotary grinding means operatively connected to the lower end of said shaft for grinding and comminuting said semi-fluid material,   a progressive-cavity, positive displacement helical pump including a generally tubular stator mounted to said housing and having an interior helical surface and a hollow rotor operatively connected to said shaft above said grinding means within said stator and having a double helical surface, and   a flexible torque tube extending through said rotor around said shaft, said tube being rigidly connected at one end to said shaft and at the other end to said rotor whereby said rotor is turned by said shaft while the rotor axis moves in an orbit about the shaft axis to define with said stator axially advancing pumping cavities for forcing fluid material from said grinder portion, under pressure from said reservoir.   
     
     
       3. In a progressing-cavity, positive displacement rotary pump assembly including a rotary shaft and drive means therefor, a generally tubular stator coaxial with said rotary shaft and having a helically formed interior surface, a .Iadd.hollow tubular .Iaddend.rotor located within said stator and having a helically formed exterior surface engaging said interior surface of sid stator to define therewith sealed pumping cavities, the improvement which comprises: a .Iadd.tubular .Iaddend.flexible member .Iadd.surrounding said shaft whereby said shaft extends through said flexible member and said rotor, .Iaddend.for coupling said rotor to said shaft, one end of said member being rigidly connected to said shaft and the other end thereof being rigidly connected to said rotor to transmit driving torque to said rotor and to flex to accommodate orbital movement of said rotor during rotation thereof.   
     
     
       4. A pump assembly as defined in claim 3 wherein .[.said rotor is tubular and.]. said flexible member is located within said rotor. .[.5. A pump assembly as defined in claim 3 wherein said rotor and said flexible member are tubular and said shaft extends through said rotor and said flexible 
     
     
        member..]. 6. A pump assembly as defined in claim .[.5.]. .Iadd.3 .Iaddend.wherein said shaft extends through and beyond said rotor and 
     
     
        wherein said flexible member is positioned entirely within said rotor. 7. A pump assembly as defined in claim 3 wherein .[.said rotor is tubular 
     
     
        and.]. said flexible member is formed integrally with said rotor. 8. A pump assembly as defined in claim 7 wherein the outer end of said shaft extending beyond said rotor is connected to a separate rotary load, said shaft being adapted to drive said rotor and said separate rotary load 
     
     
        simultaneously. 9. A pump assembly as defined in claim 7 wherein said flexible member is secured to said shaft adjacent the end of said rotor 
     
     
        furthest from said drive means for said shaft. 10. A pump assembly as defined in claim 9 wherein said rotary load is a mechanism for grinding and comminuting solid and semi-solid material contained in the product to be pumped.