Compact, modular, integral pump or turbine with coaxial fluid flow

Abstract

A coaxial pump or turbine module directs working fluid past a rotor and through a flow path symmetrically distributed within an annulus formed between an outer module housing and an inner motor or generator coil housing. The inner housing can be cooled by working fluid in the flow path, or by a cooling fluid flowing between passages of the flow path. The flow path can extend over substantially a full length and rear surface of the inner housing. The rotor can be fixed to a rotating shaft, or rotate about a fixed shaft, which can be threaded into the motor and/or module housing. A plurality of the modules can be combined into a multi-stage apparatus, with rotor speeds independently controlled by corresponding variable frequency drives. The motor or generator can include radial or axial permanent magnets and/or induction coils. Embodiments include guide vanes and/or diffusers.

I claim: 
     
         1 . A sealless pump or turbine module having an integral motor or generator, the module comprising:
 an inlet located at a proximal end of the module, the inlet being on a central axis of the module;   an outlet located at a distal end of the module, the outlet being on a central axis of the module;   an outer housing surrounding the module;   a rotor suspended within the outer housing;   a motor within the outer housing configured to drive a rotation of the rotor, or a generator within the outer housing configured to be driven by the rotation of the rotor, the motor or generator comprising:   a stator within an inner housing, the stator comprising an electromagnet directed toward the rotor; and   a plurality of magnetic devices cooperative with the rotor and configured to pass in proximity to the electromagnet as the rotor rotates; and   a flow path symmetrically distributed about the inner housing;   the module being configured to direct a flow of working fluid from the inlet through the flow path to the outlet such that the working fluid is symmetrically distributed about the inner housing as it flows past the stator within the flow path.   
     
     
         2 . The module of  claim 1 , wherein the flow path is an annular flow path surrounding the inner housing. 
     
     
         3 . The module of  claim 1 , wherein the flow path comprises a plurality of flow passages arranged symmetrically about the inner housing. 
     
     
         4 . The module of  claim 1 , wherein the rotor is suspended by a rotatable shaft, and the rotor is fixed to the shaft. 
     
     
         5 . The module of  claim 1 , wherein the rotor is suspended by a fixed shaft, and the rotor is configured to rotate about the shaft. 
     
     
         6 . The module of  claim 5 , wherein the rotor is supported on the fixed shaft by a pair of bearings, one of which maintains an axial position of the rotor while the other of which provides radial support of the rotor. 
     
     
         7 . The module of  claim 5 , wherein the rotor is supported axially and radially on the fixed shaft by a single, one-way thrust bearing. 
     
     
         8 . The module of  claim 5 , wherein the rotor is supported on the fixed shaft by at least one bearing that is lubricated by the process fluid. 
     
     
         9 . The module of  claim 5 , wherein the fixed shaft is fixed to at least one of the inner housing and the module housing. 
     
     
         10 . The module of  claim 5 , wherein the fixed shaft is fixed to at least one of the inner housing and the module housing by threaded attachment. 
     
     
         11 . The module of  claim 1 , wherein the magnetic devices are permanent magnets. 
     
     
         12 . The module of  claim 1 , wherein the magnetic devices are squirrel cage coils. 
     
     
         13 . The module of  claim 1 , wherein the magnetic devices are fixed to the rotor. 
     
     
         14 . The module of  claim 1 , wherein the magnetic devices are fixed to a disk that is coaxial with the rotor and proximal to the rotor. 
     
     
         15 . The module of  claim 1 , wherein the flow path extends over at least 50% of a surface of the inner housing, and at least 90% of the working fluid that flows through the module from the inlet to the outlet is caused to flow through in direct thermal contact with the inner housing. 
     
     
         16 . The module of  claim 1 , wherein the module is configured to require all of the working fluid flowing from the inlet to the outlet to flow through the flow path. 
     
     
         17 . The module of  claim 1 , further comprising:
 thermal insulation interposed between the flow path and the inner housing; and   a cooling fluid path formed between the thermal insulation and the inner housing, the cooling fluid path being in thermal communication with the inner housing and configured to enable an exchange of heat between the inner housing and a cooling fluid flowing through the cooling fluid path.   
     
     
         18 . The module of  claim 1 , further comprising stationary guide vanes within the flow path through which electrical wiring is routed without exposing the electrical wiring to the working fluid. 
     
     
         19 . The module of  claim 1 , wherein the stator is configured to rotate independently of the rotor and in a direction that is opposite to a rotation of direction of the rotor. 
     
     
         20 . The module of  claim 1 , further comprising a diffuser that is cooperative with the rotor but is driven by a separate diffuser motor and is thereby able to rotate independently of the rotor. 
     
     
         21 . The module of  claim 1 , wherein the electromagnet of the stator is directed toward a radial periphery of the rotor, and the magnetic devices are fixed near the radial periphery of the rotor. 
     
     
         22 . The module of  claim 1 , wherein the electromagnet of the stator is directed toward a side of the rotor, and the magnetic devices are fixed to the side of the rotor or to a disk that is coaxial with and proximal to the side of the rotor. 
     
     
         23 . A multi-stage apparatus comprising a plurality of interconnected modules, each of said modules comprising:
 an inlet located at a proximal end of the module, the inlet being on a central axis of the module;   an outlet located at a distal end of the module, the outlet being on a central axis of the module;   an outer housing surrounding the module;   a rotor suspended within the outer housing;   a motor within the outer housing configured to drive a rotation of the rotor, or a generator within the outer housing configured to be driven by the rotation of the rotor, the motor or generator comprising:   a stator within an inner housing, the stator comprising an electromagnet directed toward the rotor; and   a plurality of magnetic devices cooperative with the rotor and configured to pass in proximity to the electromagnet as the rotor rotates; and   
       a flow path symmetrically distributed about the inner housing;
 each of said modules being configured to direct a flow of working fluid from the inlet through the flow path to the outlet such that the working fluid is symmetrically distributed about the inner housing as it flows past the stator within the flow path. 
 
     
     
         24 . The apparatus of  claim 23 , wherein at least two of the motors or generators of the modules can be independently controlled so as to cause the corresponding rotors to rotate at different rates. 
     
     
         25 . The apparatus of  claim 24 , wherein the two, independently controlled motors or generators are controlled by separate variable frequency drives. 
     
     
         26 . The apparatus of  claim 23 , wherein the modules are configured such that the apparatus as a whole is able to continue functioning as a pump or as a turbine despite failure of at least one of the modules included in the apparatus. 
     
     
         27 . The apparatus of  claim 23 , further comprising control electronics that provide shared support to at least two of the modules.